38888 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Parts 141 and 142

[WH–FRL–6707–2]

RIN 2040–AB75

National Primary Drinking Water

Regulations; Arsenic and Clarifications

to Compliance and New Source

Contaminants Monitoring

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Notice of proposed rulemaking.

SUMMARY: The Environmental Protection

Agency (EPA) is proposing a drinking

water regulation for arsenic, as required

by the 1996 amendments to the Safe

Drinking Water Act (SDWA). The

proposed health-based, non-enforceable

goal, or Maximum Contaminant Level

Goal (MCLG), for arsenic is zero, and the

proposed enforceable standard, or

maximum contaminant level (MCL), for

arsenic is 0.005 mg/L. EPA is also

requesting comment on 0.003 mg/L,

0.010 mg/L and 0.020 mg/L for the MCL.

EPA is listing technologies that will

meet the MCL, including affordable

compliance technologies for three

categories of small systems serving less

than 10,000 people. This proposal also

includes monitoring, reporting, public

notification, and consumer confidence

report requirements and State primacy

revisions for public drinking water

programs affected by the arsenic

regulation.

In addition, in this proposal the

Agency is clarifying compliance for

State-determined monitoring after

exceedances for inorganic, volatile

organic, and synthetic organic

contaminants. Finally, EPA is proposing

that States will specify the time period

and sampling frequency for new public

water systems and systems using a new

source of water to demonstrate

compliance with the MCLs. The

requirement for new systems and new

source monitoring will be effective for

inorganic, volatile organic, and

synthetic organic contaminants.

DATES: EPA must receive public

comments, in writing, on the proposed

regulations by September 20, 2000. EPA

will hold a public meeting on this

proposed regulation this summer. EPA

will publish a notice of the meeting,

providing date and location, in the

Federal Register, as well as post it on

EPA’s Office of Ground Water and

Drinking Water web site at http://

www.epa.gov/safewater.

ADDRESSES: You may send written

comments to the W–99–16 Arsenic

Comments Clerk, Water Docket (MC–

4101); U.S. Environmental Protection

Agency; 1200 Pennsylvania Ave., NW,

Washington, DC 20460. Comments may

be hand-delivered to the Water Docket,

U.S. Environmental Protection Agency;

401 M Street, SW; EB–57; Washington,

DC 20460; (202) 260–3027 between 9

a.m. and 3:30 p.m. Eastern Time,

Monday through Friday. Comments may

be submitted electronically to owdocket@epamail.epa.gov. See

SUPPLEMENTARY INFORMATION for file

formats and other information about

electronic filing and docket review. The

proposed rule and supporting

documents, including public comments,

are available for review in the Water

Docket at the above address.

FOR FURTHER INFORMATION CONTACT:

Regulatory information: Irene Dooley,

(202) 260–9531, email:

dooley.irene@epa.gov. Benefits: Dr. John

B. Bennett, (202) 260–0446, email:

bennett.johnb@epa.gov General

information about the regulation: Safe

Drinking Water Hotline, phone: (800)

426–4791, or (703) 285–1093, email:

hotline.sdwa@epa.gov.

SUPPLEMENTARY INFORMATION:

Regulated Entities

A public water system, as defined in

40 CFR 141.2, provides water to the

public for human consumption through

pipes or other constructed conveyances,

if such system has ‘‘at least fifteen

service connections or regularly serves

an average of at least twenty-five

individuals daily at least 60 days out of

the year.’’ A public water system is

either a community water system (CWS)

or a non-community water system

(NCWS). A community water system, as

defined in § 141.2, is ‘‘a public water

system which serves at least fifteen

service connections used by year-round

residents or regularly serves at least

twenty-five year-round residents.’’ The

definition in § 141.2 for a non-transient,

non-community water system

[NTNCWS] is ‘‘a public water system

that is not a [CWS] and that regularly

serves at least 25 of the same persons

over 6 months per year.’’ EPA has an

inventory totaling over 54,000

community water systems and

approximately 20,000 non-transient,

non-community water systems

nationwide. Entities potentially

regulated by this action are community

water systems and non-transient, noncommunity water systems. The

following table provides examples of the

regulated entities under this rule.

TABLE OF REGULATED ENTITIES

Category Examples of potentially regulated entities

Industry ............................................................... Privately owned/operated community water supply systems using ground water or mixed

ground water and surface water.

State, Tribal, and Local Government ................. State, Tribal, or local government-owned/operated water supply systems using ground water

or mixed ground water and surface water.

Federal Government ........................................... Federally owned/operated community water supply systems using ground water or mixed

ground water and surface water.

The table is not intended to be

exhaustive, but rather provides a guide

for readers regarding entities likely to be

regulated by this action. This table lists

the types of entities that EPA is now

aware could potentially be regulated by

this action. Other types of entities not

listed in this table could also be

regulated. To determine whether your

facility is regulated by this action, you

should carefully examine the

applicability criteria in §§ 141.11 and

141.62 of the rule. If you have any

questions regarding the applicability of

this action to a particular entity, consult

Irene Dooley, the regulatory information

person listed in the FOR FURTHER

INFORMATION CONTACT section.

Additional Information for Commenters

Please submit an original and three

copies of your comments and enclosures

(including references). To ensure that

EPA can read, understand, and therefore

properly respond to comments, the

Agency would prefer that comments

cite, where possible, the paragraph(s) or

sections in the notice or supporting

documents to which each comment

refers. Commenters should use a

separate paragraph for each issue

discussed. Electronic comments must be

submitted as a WordPerfect 5.1, WP6.1

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38889

or WP8 file or as an ASCII file avoiding

the use of special characters. Comments

and data will also be accepted on disks

in WP5.1, WP6.1 or WP8, or ASCII file

format. Electronic comments on this

Notice may be filed online at many

Federal Depository Libraries.

Commenters who want EPA to

acknowledge receipt of their comments

should include a self-addressed,

stamped envelope. No facsimiles (faxes)

will be accepted.

Availability of Docket

The docket for this rulemaking has

been established under number W–99–

16, and includes supporting

documentation as well as printed, paper

versions of electronic comments. The

docket is available for inspection from

9 a.m. to 4 p.m., Monday through

Friday, excluding legal holidays, at the

Water Docket; EB 57; U.S. EPA; 401 M

Street, SW; Washington, D.C. For access

to docket materials, please call (202)

260–3027 to schedule an appointment.

Abbreviations Used in This Proposed

Rule

>—greater than

≥—greater than or equal to

<—less than

≤—less than or equal to

§ —Section

ACWA—Association of California Water

Agencies

AA—activated alumina

As (III)—trivalent arsenic. Common

inorganic form in water is arsenite

As (V)—pentavalent arsenic. Common

inorganic form in water is arsenate

ATSDR—Agency for Toxic Substances

and Disease Registry, U.S. Department

of Health & Human Services

ASTM—American Society for Testing

and Materials

ASV—anodic stripping voltammetry

AWQC—Ambient Water Quality

Criterion

AWWA—American Water Works

Association

BAT—best available technology

BFD—Blackfoot disease

BOD—biochemical oxygen demand

BOSC—Board of Scientific Counselors,

ORD

CASRN—Chemical Abstracts Service

registration number

CCA—chromated copper arsenate

CCR—consumer confidence report

CDC—Centers for Disease Control and

Prevention

CFR—Code of Federal Regulations

CPI—Consumer Price Index

CSFII—Continuing Survey of Food

Intakes by Individuals

CV—coefficient of variation=standard

deviation divided by the mean × 100

CWS—community water system

CWSS—Community Water System

Survey

DBPs—disinfection byproducts

DBPR—Disinfectants/Disinfection Byproducts Rule

DMA—Di-methyl arsinic acid, cacodylic

acid, (CH3)2HAsO2

DSMA—Disodium methanearsonate

DWSRF—Drinking Water State

Revolving Fund

DNA—Deoxyribonucleic acid

EB—East Tower Basement

EDL—Estimated Detection Limit

EDR—Electrodialysis Reversal

e.g.—such as

EJ—Environmental Justice

EO—Executive Order

EPA—U.S. Environmental Protection

Agency

FDA—Food and Drug Administration

FR—Federal Register

FTE—full-time equivalents (employees)

GDP—Gross Domestic Product

GFAA—Graphite Furnace Atomic

Absorption

GHAA—Gaseous Hydride Atomic

Absorption

GI—gastrointestinal

gw—ground water

HRRCA—Health Risk Reduction and

Cost Analysis

IARC—International Agency for

Research on Cancer

ICP–MS—Inductively Coupled Plasma

Mass Spectroscopy

i.e.—that is

ICP–AES—Inductively Coupled PlasmaAtomic Emission Spectroscopy

IESWTR—Interim Enhanced Surface

Water Treatment Rule

IOCs—inorganic contaminants

IRFA—Initial Regulatory Flexibility

Analysis

IRIS—Integrated Risk Information

System

IX—Ion exchange

K—thousands

kg—kilogram, which is one thousand

grams

L—Liter, also referred to as lower case

‘‘l’’ in older citations

LC50—The concentration of a chemical

in air or water which is expected to

cause death in 50% of test animals

living in that air or water

LCP—laboratory certification program

LD50—The dose of a chemical taken by

mouth or absorbed by the skin which

is expected to cause death in 50% of

the test animals so treated

LOAEL—Lowest-observed-adverseeffect level

LS—lime softening

LT2ESWTR—Long-Term 2 Enhanced

Surface Water Treatment Rule

M—millions

m3—Cubic meters

MCL—maximum contaminant level

MCLG—maximum contaminant level

goal

MDL—method detection limit

Metro—Metropolitan Water District of

Southern California

mg—Milligrams—one thousandth of

gram, 1 milligram = 1,000 micrograms

mg/kg—milligrams per kilogram

mg/m3—Milligrams per cubic meter

microgram (μg)—One-millionth of gram

(3.5 × 10¥8 oz., 0.000000035 oz.)

μg/L—micrograms per liter

M/DBP—Microbial/Disinfection Byproduct

MMA—Mono-methyl arsenic, arsonic

acid, CH3H2AsO3

MOS—margin of safety

MSMA—Monosodium methanearsonate

NAOS—National Arsenic Occurrence

Survey

NAS—National Academy of Sciences

NAWQA—National Ambient Water

Quality Assessment, USGS

NCI—National Cancer Institute

NCWS—non-community water system

NDWAC—National Drinking Water

Advisory Council

NELAC—National Environmental

Laboratory Accreditation Council

NIRS—National Inorganic and

Radionuclide Survey

NIST—National Institute of Standards

and Technology

NOAEL—No-observed-adverse-effect

level

NODA—notice of data availability

NOEL—No-observed-effect level

NPDWR—National Primary Drinking

Water Regulation, OGWDW

NRC—National Research Council, the

operating arm of NAS

NTNCWS—non-transient noncommunity water system

NTTAA—National Technology Transfer

and Advancement Act of 1995

NWIS—National Water Information

System

O&M—operational and maintenance

OGWDW—Office of Ground Water and

Drinking Water

PBMS—Performance-Based

Measurement System

PE—performance evaluation, studies to

certify laboratories for EPA drinking

water testing

P.L.—Public Law

PNR—Public notification rule

POD—point of departure

POE—Point-of-entry treatment devices

POU—Point-of-use treatment devices

ppb—Parts per billion. Also, μg/L or

micrograms per liter

ppm—Parts per million. Also, mg/L or

milligrams per liter

PQL—Practical quantitation level

PRA—Paperwork Reduction Act

PT—performance testing

PWS—Public water systems

PWSS—Public Water Systems

Supervision

RCRA—Resource Conservation and

Recovery Act

38890 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

REFs—relative exposure factors

RFA—Regulatory Flexibility Act

RfD—Reference dose

RIA—Regulatory Impact Analysis

RMCL—Recommended Maximum

Contaminant Level

RO—reverse osmosis

RWS—Rural Water Survey

SAB—Science Advisory Board

SBA—Small Business Administration

SBREFA—Small Business Regulatory

and Enforcement Flexibility Act, SBA

SDWA—Safe Drinking Water Act of

1974, as amended

SDWIS—Safe Drinking Water

Information System

SER—Small Entity Representative for

SBREFA

SISNOSE—Substantial impact on a

significant number of small entities,

SBREFA

SM—Standard Methods for the

Examination of Water and Wastewater

SMRs—Standardized mortality ratios,

comparing deaths in test areas to

deaths in unexposed areas

SSCTs—Small System Compliance

Technologies

STP–GFAA—Stabilized Temperature

Platform Graphite Furnace Atomic

Absorption

SW—Office of Solid Waste publication

or test method

SW–846—Solid Waste publication #846,

Test Methods for Solid and Hazardous

Waste

TC—toxicity characteristic

TDS—total dissolved solids

TNC—transient, non-community

TOC—total organic carbon

μg—Microgram, 1000 micrograms = 1

milligram

UMRA—Unfunded Mandates Reform

Act

U.S.—United States

USDA—U.S. Department of Agriculture

USGS—U.S. Geological Survey

USPHS—U.S. Public Health Service

VSL—Value of Statistical Life

WESTCAS—Western Coalition of Arid

States

WHO—World Health Organization

WITAF—Water Industry Technical

Action Fund

WS—water supply

WTP—Willingness to pay

Table of Contents

I. Summary of Regulation

II. Background

A. What is the Statutory Authority for the

Arsenic Drinking Water Regulation?

B. What is arsenic?

C. What are the sources of arsenic

exposure?

1. Natural Sources of Arsenic

2. Industrial Sources of Arsenic

3. Dietary Sources

4. Environmental Sources

D. What is the regulatory history for

arsenic?

1. Earliest U.S. Arsenic Drinking Water

Standards

2. EPA’s 1980 Guidelines

3. Research and Regulatory Work

E. EPA’s Arsenic Research Plan

III. Toxic Forms and Health Effects of Arsenic

A. What are the toxic forms of arsenic?

B. What are the effects of acute toxicity?

C. What cancers are associated with

arsenic?

1. Skin Cancer

2. Internal Cancers

D. What non-cancer effects are associated

with arsenic?

E. What are the recent developments in

health effects research?

1. Funding of Health Effects Research

2. Expert Panel on Arsenic Carcinogenicity

3. NAS Review of EPA’s Risk Assessment

4. May 1999 Utah Mortality Study

5. 1999 Review of health effects

6. Study of Bladder and Kidney Cancer in

Finland

F. What did the National Academy of

Sciences/National Research Council

report?

1. The National Research Council and its

Charge

2. Exposure

3. Essentiality

4. Metabolism and Disposition

5. Human Health Effects and Variations in

Sensitivity

6. Modes of Action

7. Risk Considerations

8. Risk Characterization

IV. Setting the MCLG

A. How did EPA approach it?

B. What is the MCLG?

C. How will a health advisory protect

potentially sensitive subpopulations?

D. How will the Clean Water Act criterion

be affected by this regulation?

V. EPA’s Estimates of Arsenic Occurrence

A. What data did EPA evaluate?

B. What databases did EPA use?

C. How did EPA estimate national

occurrence of arsenic in drinking water?

D. What are the national occurrence

estimates of arsenic in drinking water for

community water systems?

E. How do EPA’s estimates compare with

other recent national occurrence

estimates?

F. What are the national occurrence

estimates of arsenic in drinking water for

non-transient, non-community water

systems?

G. How do arsenic levels vary from source

to source and over time?

H. How did EPA evaluate co-occurrence?

1. Data

2. Results of the Co-occurrence Analysis

(US EPA, 1999f)

VI. Analytical Methods

A. What section of SDWA requires the

Agency to specify analytical methods?

B. What factors does the Agency consider

in approving analytical methods?

C. What analytical methods and method

updates are currently approved for the

analysis of arsenic in drinking water?

D. Will any of the approved methods for

arsenic analysis be withdrawn?

E. Will EPA propose any new analytical

methods for arsenic analysis?

F. Other Method-Related Items

1. The Use of Ultrasonic Nebulization with

ICP–MS

2. Performance-Based Measurement

System

G. What are the estimated costs of analysis?

H. What is the practical quantitation limit?

1. PQL determination

2. PQL for arsenic

I. What are the sample collection, handling

and preservation requirements for

arsenic?

J. Laboratory Certification

1. Background

2. What Are the Performance Testing

criteria for arsenic?

3. How often is a laboratory required to

demonstrate acceptable PT performance?

4. Externalization of the PT Program

(formerly known as the PE Program)

VII. Monitoring and Reporting Requirements

A. What are the existing monitoring and

compliance requirements?

B. How does the Agency plan to revise the

monitoring requirements?

C. Can States grant monitoring waivers?

D. How can I determine if I have an MCL

violation?

E. When will systems have to complete

initial monitoring?

F. Can I use grandfathered data to satisfy

the initial monitoring requirement?

G. What are the monitoring requirements

for new systems and sources?

H. How does the Consumer Confidence

Report change?

I. How will public notification change?

VIII. Treatment Technologies

A. What are the Best Available

Technologies (BATs) for arsenic? What

are the issues associated with these

technologies?

B. What are the likely treatment trains?

How much will they cost?

C. How are variance and compliance

technologies identified for small

systems?

D. When are exemptions available?

E. What are the small systems compliance

technologies?

F. How does the Arsenic Regulation

overlap with other regulations?

IX. Costs

A. Why does EPA analyze the regulatory

burden?

B. How did EPA prepare the baseline

study?

1. Use of baseline data

2. Key data sources used in the baseline

analysis for the RIA?

C. How were very large system cost

derived?

D. How did EPA develop cost estimates?

E. What are the national treatment costs of

different MCL options?

1. Assumptions affecting the development

of the decision tree

2. Assumptions affecting unit cost curves

X. Benefits of Arsenic Reduction

A. Monetized Benefits of Avoiding Bladder

Cancer

1. Risk reductions: The Analytic Approach

2. Water Consumption

3. Monte Carlo Analysis

4. Relative Exposure Factors

5. NRC Risk Distributions

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38891

6. Estimated Risk Reductions

B. ‘‘What if?’’ scenario for lung cancer risks

C. Evaluation of Benefits

1. Fatal Risks and Value of a Statistical Life

(VSL)

2. Nonfatal Risks and Willingness to Pay

(WTP)

D. Estimates of Quantifiable Benefits of

Arsenic Reduction

F. NDWAC Working Group (NDWAC,

1988) on Benefits

XI. Risk Management Decisions: MCL and

NTNCWSs

A. What is the Proposed MCL?

1. Feasible MCL

2. Principal Considerations in Analysis of

MCL Options

3. Findings of NRC and Consideration of

Risk Levels

4. Non-monetized Health Effects

5. Sources of Uncertainty

6. Comparison of Benefits and Costs

7. Conclusion and Request for Comment

B. Why is EPA proposing a total arsenic

MCL?

C. Why is EPA proposing to require only

monitoring and notification for

NTNCWSs?

1. Methodology for analyzing NTNCWS

risks

2. Results

XII. State Programs

A. How does arsenic affect a State’s

primacy program?

B. When does a State have to apply?

C. How are Tribes affected?

XIII. HRRCA

A. What are the requirements for the

HRRCA?

B. What are the quantifiable and nonquantifiable health risk reduction

benefits?

C. What are the Quantifiable and NonQuantifiable Costs?

D. What are the Incremental Benefits and

Costs?

E. What are the Risks of Arsenic Exposure

to the General Population and Sensitive

Subpopulations?

F. What are the Risks Associated with CoOccurring Contaminants?

G. What are the Uncertainties in the

Analysis?

XIV. Administrative Requirements

A. Executive Order 12866: Regulatory

Planning and Review

B. Regulatory Flexibility Act (RFA), as

amended by the Small Business

Regulatory Enforcement Fairness Act of

1996 (SBREFA), 5 U.S.C. 601 et seq.

1. Overview

2. Use of Alternative Small Entity

Definition

3. Initial Regulatory Flexibility Analysis

a. Number of Small Entities Affected

b. Reporting, Recordkeeping and Other

Requirements for Small Systems

4. Small Business Advocacy Review

(SBAR) Panel Recommendations

C. Unfunded Mandates Reform Act (UMRA)

1. Summary of UMRA Requirements

a. Authorizing legislation

b. Cost-benefit analysis

c. Financial Assistance

d. Estimates of future compliance costs and

disproportionate budgetary effects

e. Macroeconomic effects

f. Summary of EPA’s consultation with

State, local, and tribal governments and

their concerns

g. Nature of State, local, and Tribal

government concerns and how EPA

addressed these concerns

h. Regulatory Alternatives Considered

2. Impacts on Small Governments

D. Paperwork Reduction Act (PRA)

E. National Technology Transfer and

Advancement Act (NTTAA)

F. Executive Order 12898: Environmental

Justice

G. Executive Order 13045: Protection of

Children from Environmental Health

Risks and Safety Risks

H. Executive Order 13132: Federalism

I. Executive Order 13084: Consultation and

Coordination with Indian Tribal

Governments

J. Request for Comments on Use of Plain

Language

XV. References

List of Tables

Table V–1. Summary of Arsenic Data Sources

Table V–2. Regional Exceedance Probability

Distribution Estimates

Table V–3. Statistical Estimates of Number of

Ground Water CWSs with Average

Arsenic Concentrations in Specified

Ranges

Table V–4. Statistical Estimates of Number of

Surface Water CWSs with Average

Arsenic Concentrations in Specified

Ranges

Table V–5. Comparison of CWSs from EPA,

NAOS, and USGS Estimates Exceeding

Arsenic Concentrations

Table V–6. Statistical Estimates of Number of

Ground Water NTNCWSs with Average

Arsenic Concentrations in Specified

Ranges

Table V–7. Statistical Estimates of Number of

Surface Water NTNCWSs with Average

Arsenic Concentrations in Specified

Ranges

Table V–8. Correlation of Arsenic with

Sulfate and Iron (surface and ground

waters)

Table V–9. Correlation of Arsenic with Radon

(ground water)

Table VI–1. Approved Analytical Methods

(and Method Updates) for Arsenic (CFR

141.23)

Table VI–2. Estimated Costs for the Analysis

of Arsenic in Drinking Water

Table VI–3. Acceptance Limits and PQLs for

Other Metals (in order of decreasing

PQL)

Table VII–1. Comparison of Sampling,

Monitoring, and Reporting Requirements

Table VII–2. Treatment in-place at small

water systems (US EPA, 1999e and US

EPA, 1999m)

Table VII–3. Table Identifying Regulatory

Changes

Table VII–4. Table Listing Deleted Sections

Table VIII–1. Best Available Technologies

and Removal Rates

Table VIII–2. Treatment Technology Trains

Table VIII–3. Annual Costs of Treatment

Trains (Per household)

Table VIII–4. Affordable Compliance

Technology Trains for Small Systems

Table VIII–5. Affordable Compliance

Technology Trains for Small Systems

Table IX–1. Summary of General Baseline

Categories of Affected Entities

Table IX–2. List of Large Water Systems that

Serve More Than 1 Million People

Table IX–3. Total Annual Costs for Large

Systems for (serving more than 1 million

people)

Table IX–4. Systems Needing to Add PreOxidation

Table IX–5. Percent of Systems with

Coagulation-Filtration and LimeSoftening in Place

Table IX–6. Waste Disposal Options

Table IX–7. Ground Water: Arsenic and

Sulfate

Table IX–8. Surface Water: Arsenic and

Sulfate

Table IX–9. Ground Water: Arsenic and Iron

Table IX–10. Surface Water: Arsenic and Iron

Table IX–11. National Annual Treatment

Costs (Dollars in Millions)

Table IX–12. Total Annual Costs per

Household (Dollars)

Table IX–13. Incremental National Annual

Costs (Dollars in Millions)

Table IX–14. Incremental Annual Costs per

Household (Dollars)

Table X–1. Source of Water Consumed

Table X–2a. Bladder Cancer Incidence Risks 1

for High Percentile U.S. Populations

Exposed At or Above MCL Options,

After Treatment 2 (Community Water

Consumption Data 3)

Table X–2b. Bladder Cancer Incidence Risks1

for High Percentile U.S. Populations

Exposed At or Above MCL Options,

After Treatment 2 (Total Water

Consumption Data 3)

Table X–3a. Percent of Exposed Population

At 10 ndash;4 Risk or Higher for

Bladder Cancer Incidence1 After

Treatment 2 (Community Water

Consumption Data 3)

Table X–3b. Percent of Exposed Population

At 10 ndash;4 Risk or Higher for

Bladder Cancer Incidence1 After

Treatment 2 (Total Water Consumption

Data 3)

Table X–4a. Mean Bladder Cancer Incidence

Risks 1 for U.S. Populations Exposed At

or Above MCL Options, after Treatment 2

(Community Water Consumption Data 3)

Table X–4b. Mean Bladder Cancer Incidence

Risks 1 for U.S. Populations Exposed At

or Above MCL Options, after Treatment 2

(Total Water Consumption Data 3)

Table X–5. Lifetime Avoided Medical Costs

For Survivors (preliminary estimates,

1996 dollars 1)

Table X–6. Mean Bladder Cancer Incidence

Risks 1 for U.S. Populations Exposed At

or Above MCL Options, after Treatment 2

(Composite of Tables X–5a and X–5b)

Table X–7. Estimated Costs and Benefits from

Reducing Arsenic in Drinking Water

($millions, 1999)

Table XI–1. Estimated Costs and Benefits

from Reducing Arsenic in Drinking

Water (In 1999 $ millions)

Table XI–2. Exposure Factors Used in the

NTNC Risk Assessment

Table XI–3. Composition of Non-Transient,

Non-Community Water Systems

(Percentage of Total NTNC Population

Served by Sector)

38892 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

Table XI–4. Upper Bound School Children

Risk Associated with Current Arsenic

Exposure in NTNC Water Systems

Table XI–5. Non-Transient Non-Community

Benefit Cost Analysis

Table XI–6. Sensitive Group Evaluation

Lifetime Risks

Table XIII–1. Risk Reduction from Reducing

Arsenic in Drinking Water

Table XIII–2. Mean Bladder Cancer Risks and

Exposed Population

Table XIII–3. Estimated Costs and Benefits

from Reducing Arsenic in Drinking

Water (in 1999 $ millions)

Table XIII–4. Estimated Annualized National

Costs of Reducing Arsenic Exposures (in

1999 $ millions)

Table XIII–5. Estimated Annual Costs per

Household 1 (in 1999 $)

Table XIII–6. Summary of the Total Annual

National Costs of Compliance with the

Proposed Arsenic Rule Across MCL

Options (in 1997 $ millions)

Table XIII–7. Estimates of the Annual

Incremental Risk Reduction, Benefits,

and Costs of Reducing Arsenic in

Drinking Water ($millions, 1999)

Table XIV–1. Profile of the Universe of Small

Water Systems Regulated Under the

Arsenic Rule

Table XIV–2. Average Annual Cost per CWS

by Ownership

Table XIV–3. Average Compliance Costs per

Household for CWSs Exceeding MCLs

Table XIV–4. Average Compliance Costs per

Household for CWSs Exceeding MCLs as

a Percent of Median Household Income

Table XIV–5. Hour Burden per Activity for

Public Water Systems

Table XIV–6. Hour Burden per Activity for

States and Tribes

I. Summary of Regulation

EPA is proposing an arsenic

regulation for community water

systems, which are systems that provide

piped water to at least fifteen service

connections used by year-round

residents or regularly serves at least

twenty-five year-round residents. This

proposal will require non-transient,

non-community water systems

(NTNCWS) to monitor for arsenic and

report exceedances of the MCL. The

proposed health-based, non-enforceable

goal, or Maximum Contaminant Level

Goal (MCLG), is zero, based on EPA’s

revised risk characterization.

EPA evaluated the analytical

capability and laboratory capacity,

likelihood of water systems choosing

treatment technologies for several sizes

of systems based on source water

properties, and the national occurrence

of arsenic in water supplies to

determine the proposed Maximum

Contaminant Level (MCL). Furthermore,

the Agency analyzed the quantifiable

and nonquantifiable costs and health

risk reduction benefits likely to occur at

the treatment levels considered, and the

effects on sensitive subpopulations.

Based on the determination that the

costs for the feasible MCL do not justify

the benefits, EPA is proposing an MCL

of 0.005 mg/L and requesting comment

on 0.003 mg/L, 0.010 mg/L, and 0.020

mg/L. The treatment technologies for

large systems are primarily coagulation/

filtration and lime softening, while EPA

expects that small systems (serving less

than 10,000 people) will be able to use

ion exchange, activated alumina, reverse

osmosis, nanofiltration, and

electrodialysis reversal. The effective

date will be five years after the final rule

comes out for community water systems

serving 10,000 people or less, and three

years after promulgation for all other

community water systems. EPA is

proposing that States applying to adopt

the revised arsenic MCL may use their

most recently approved monitoring and

waiver plans or note in their primacy

application any revisions to those plans.

The Agency is clarifying the

procedure used for determining

compliance after exceedances for

inorganic, volatile organic, and

synthetic organic contaminants in this

proposal. Finally, EPA is proposing in

this proposal that States will specify the

time frame which new systems and

systems using a new source of water

have to demonstrate compliance with

the MCL’s including initial sampling

frequencies and compliance periods for

new systems and systems that use a new

source of water for inorganic, volatile

organic, and synthetic organic

contaminants.

II. Background

A. What Is the Statutory Authority for

the Arsenic Drinking Water Regulation?

Section 1401 of the Safe Drinking

Water Act (SDWA) requires a ‘‘primary

drinking water regulation’’ to specify a

maximum contaminant level (MCL) if it

is economically and technically feasible

to measure the contaminant and include

testing procedures to insure compliance

with the MCL and proper operation and

maintenance. In addition, section

1401(1)(D)(i) requires EPA to establish

the minimum quality of untreated, or

raw, water taken into a public water

system. A national primary drinking

water regulation (NPDWR) that

establishes an MCL also lists the

technologies that are feasible to meet the

MCL, but systems are not required to

use the listed technologies (section

1412(b)(3)(E)(i)). As a result of the 1996

amendments to SDWA, when issuing a

NPDWR, EPA will also list affordable

technologies for small systems serving

10,000 to 3301, 3300 to 501, and 500 to

25 that achieve compliance with the

MCL or treatment technique. EPA can

list modular (packaged) and point-ofentry and point-of-use treatment units

for the three small system sizes, as long

as the units are maintained by the

public water system or its contractors.

Home units must contain mechanical

warnings to notify customers of

problems (section 1412(b)(4)(E)(ii)). In

section 1412(b)(12)(A) of SDWA, as

amended August 6, 1996, Congress

directed EPA to propose a national

primary drinking water regulation for

arsenic by January 1, 2000 and issue the

final regulation by January 1, 2001. At

the same time, Congress directed EPA to

develop a research plan by February 2,

1997 to reduce the uncertainty in

assessing health risks from low levels of

arsenic and conduct the research in

consultation with the National Academy

of Sciences, other Federal agencies, and

interested public and private entities.

The amendments allowed EPA to enter

into cooperative agreements for

research.

Section 1412(a)(3) requires EPA to

propose a maximum contaminant level

goal (MCLG) simultaneously with the

national primary drinking water

regulation. The MCLG is defined in

section1412(b)(4)(A) as ‘‘the level at

which no known or anticipated adverse

effects on the health of persons occur

and which allows an adequate margin of

safety.’’ Section 1412(b)(4)(B) specifies

that each national primary drinking

water regulation will specify a

maximum contaminant level (MCL) as

close to the MCLG as is feasible, with

two exceptions added in the 1996

amendments. First, the Administrator

may establish an MCL at a level other

than the feasible level if the treatment

to meet the feasible MCL would increase

the risk from other contaminants or the

technology would interfere with the

treatment of other contaminants

(section1412(b)(5)). Second, if benefits

at the feasible level would not justify

the costs, EPA may propose and

promulgate an MCL ‘‘that maximizes

health risk reduction benefits at a cost

that is justified by the benefits (section

1412(b)(6)).’’

When proposing an MCL, EPA must

publish, and seek public comment on,

the health risk reduction and cost

analyses (HRRCA) of each alternative

maximum contaminant level considered

(section 1412(b)(3)(C)(i)). This includes

the quantifiable and nonquantifiable

benefits from reductions in health risk,

including those from removing cooccurring contaminants (not counting

benefits resulting from compliance with

other proposed or final regulations),

costs of compliance (not counting costs

resulting from other regulations), any

increased health risks (including those

from co-occurring contaminants) that

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38893

may result from compliance,

incremental costs and benefits of each

alternative MCL considered, and the

effects on sensitive subpopulations (e.g.,

infants, children, pregnant women,

elderly, seriously ill, or other groups at

greater risk). EPA must analyze the

quality and extent of the information,

the uncertainties in the analysis, and the

degree and nature of the risk.

The 1996 amendments also require

EPA to base its action on the best

available, peer-reviewed science and

supporting studies and to present health

effects information to the public in an

understandable fashion. To meet the

latter obligation, EPA must specify,

among other things, the methodology

used to reconcile inconsistencies in the

scientific data for the final regulation

(section 1412(b)(3)(B)(v)).

Section 1451(a) allows EPA to

delegate primary enforcement

responsibility to federally recognized

Indian Tribes, providing grant and

contract assistance, using the

procedures applied to States. Section

1413(a)(1) allows EPA to grant States

primary enforcement responsibility for

NPDWRs when EPA has determined

that the State has adopted regulations

that are no less stringent than EPA’s.

States must adopt comparable

regulations within two years of EPA’s

promulgation of the final rule, unless a

two-year extension is justified. State

primacy also requires, among other

things, adequate enforcement (including

monitoring and inspections) and

reporting. EPA must approve or deny

State applications within 90 days of

submission (section 1413(b)(2)). In some

cases, a State submitting revisions to

adopt a national primary drinking water

regulation has enforcement authority for

the new regulation while EPA action on

the revision is pending (section

1413(c)).

B. What Is Arsenic?

Arsenic is an element that occurs

naturally in rocks, soil, water, air,

plants, and animals. Arsenic is a

metalloid, which exhibits both metallic

and nonmetallic chemical and physical

properties. The primary valence states

for arsenic are 0, ¥3, +3 and +5.

Although arsenic is found in nature to

a small extent in its elemental form (0

valence), it occurs most often as

inorganic and organic compounds in

either the As (III) (+3) or As (V) (+5)

valence states. The trivalent forms of

inorganic arsenic [As (III) (e.g., arsenite,

H3AsO3)] and the pentavalent forms [As

(V) (e.g., arsenate, H2AsO4

¥, HAsO4

2¥)]

are inorganic species which tend to be

more prevalent in water than the

organic arsenic species (Irgolic, 1994;

Clifford and Zhang, 1994). The

dominant inorganic species present in

water is largely a function of the pH and

the oxidizing/reducing conditions

which affects the need for pretreatment

and removal effects. Arsenates are more

likely to occur in aerobic surface waters

and arsenites are more likely to occur in

anaerobic ground waters.

C. What Are the Sources of Arsenic

Exposure?

1. Natural Sources of Arsenic

There are numerous natural sources

as well as human activities that may

introduce arsenic into food and drinking

water. The primary natural sources

include geologic formations (e.g., rocks,

soil, and sedimentary deposits),

geothermal activity, and volcanic

activity. Arsenic and its compounds

comprise 1.5–2% of the earth’s crust

(Welch, personal communication).

While concentrations of arsenic in the

earth’s crust vary, the average

concentrations are generally reported to

range from 1.5 to 5 mg/kg. Arsenic is a

major constituent of many mineral

species in igneous and sedimentary

rocks. It is commonly present in the

sulfide ores of metals including copper,

lead, silver, and gold. There are over

100 arsenic-containing minerals,

including arsenic pyrites (e.g., FeAsS),

realgar (AsS), lollingite (FeAs2, Fe2As3,

Fe2As5), and orpiment (As2S3).

Geothermal water can be a source of

inorganic arsenic in surface water and

ground water. Welch et al. (1988)

identified fourteen areas in the Western

United States where dissolved arsenic

concentrations ranged from 80 to 15,000

μg/L. In addition, natural emissions of

arsenic are associated with forest fires

and grass fires. Volcanic activity

appears to be the largest natural source

of arsenic emissions to the atmosphere

(ATSDR, 1998). Arsenic compounds,

both inorganic and organic, are also

found in food.

2. Industrial Sources of Arsenic

Major present and past sources of

arsenic include wood preservatives,

agricultural uses, industrial uses,

mining and smelting. The human

impact on arsenic levels in water

depends on the level of human activity,

the distance from the pollution sources,

and the dispersion and fate of the

arsenic that is released. The production

of chromated copper arsenate (CCA), an

inorganic arsenic compound and wood

preservative, accounts for

approximately 90% of the arsenic used

annually by industry in the United

States (USGS, 1998; USGS, 1999). CCA

is used to pressure treat lumber, which

is typically used for the construction of

decks, fences, and other outdoor

applications. In addition to wood

preservatives, the other EPA-registered

use of inorganic arsenic is for sealed ant

bait. In the past, agricultural uses of

arsenic included pesticides, herbicides,

insecticides, defoliants, and soil

sterilants. Inorganic arsenic pesticides

are no longer used for agricultural

purposes; the last agricultural

application was voluntarily canceled in

1993 (58 FR 64579, US EPA, 1993b).

Organic forms of arsenic are

constituents of some agricultural

pesticides that are currently used in the

U.S. Monosodium methanearsonate

(MSMA) is the most widely applied

organoarsenical pesticide, which is used

to control broadleaf weeds and is

applied to cotton (Jordan et al., 1997).

Small amounts of disodium

methanearsonate (DSMA, or cacodylic

acid) are also applied to cotton fields as

herbicides. The Food and Drug

Administration regulates other organic

arsenicals (e.g., roxarsone and arsanilic

acid) used as feed additives for poultry

and swine for increased rate of weight

gain, improved feed efficiencies,

improved pigmentation, and disease

treatment and prevention. These

additives undergo little or no

metabolism before excretion (NAS,

1977; Moody and Williams, 1964;

Aschbacher and Feil, 1991).

Arsenic and arsenic compounds

(arsenicals) are used for a variety of

industrial purposes, including:

electrophotography, catalysts,

pyrotechnics, antifouling paints,

pharmaceutical substances, dye and

soaps, ceramics, alloys (automotive

solder and radiators), battery plates,

optoelectronic devices, semiconductors,

and light emitting diodes in digital

watches (Azcue and Nriagu, 1994). In

addition, burning of fossil fuels,

combustion of wastes, mining and

smelting, pulp and paper production,

glass manufacturing, and cement

manufacturing can result in emissions

of arsenic to the environment (US EPA,

1998). Arsenic has been identified as a

contaminant of concern at 916 of the

1,467 National Priorities List

(Superfund) hazardous waste sites

(ATSDR, 1998).

3. Dietary Sources

Because arsenic is naturally

occurring, the entire population is

exposed to low levels of arsenic through

food, water, air, and contact with soil.

The National Research Council report

(NRC, 1999) described in sections III.C.

and III.E.3. provides Food and Drug

Administration (FDA) ‘‘market basket’’

data for total arsenic intake by age

38894 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

group. NRC assumed that, for fish and

seafood, inorganic arsenic is 10% of the

total arsenic and that other food

contains entirely inorganic arsenic.

These assumptions are probably high

and conservative for public health

protection to avoid underestimating the

contributions from food. Table 3–5 in

the 1999 NRC report characterizes

inorganic arsenic intake from food in

the U.S. as being 1.3 μg/day for infants

under one year old, 4.4 μg/day for 2-year

olds, almost 10 μg/day for 25–30 yearold males, with a maximum of 12.5 μg/

day for 60–65 year-old males (females

had lower arsenic intake in every age

group). MacIntosh et al. (1997)

estimated that 785 adults had a mean

inorganic arsenic consumption of 10.22

μg/day, with a standard deviation of

6.54 μg/day and a range of 0.36–123.84

μg/day based on semi-quantitative food

surveys.

Likewise, the 2 L/day assumption of

adult drinking water intake used to

develop the MCLG does not represent

intake by the average person; rather it

represents intake of a person in the 90th

percentile. (See Section X.B.1.a. for a

description of water consumption for

the general population.)

4. Environmental Sources

Internal exposure after skin contact

with water or soil containing arsenic or

inhalation of arsenic from air is believed

to be low. Studies of inorganic arsenic

absorption from skin from cadavers

estimated 0.8% uptake from soil and

1.9% uptake from water over a 24-hour

period (Wester et al., 1993). EPA’s

arsenic health assessment document for

the Clean Air Act (US EPA, 1984) cited

respiratory arsenic as being about 0.12

μg/day from a daily ventilation rate of

20 m3 using a 1981 national average

arsenic air concentration of 0.006 μg/m3.

Assuming 30 percent absorption, the

daily amount of arsenic from breathing

would be 0.03 μg, so air is a minor

source of arsenic (50 FR 46936 at 46960;

US EPA, 1985b). At this time, EPA is

basing health risks on estimates of

arsenic exposure from food and water.

The Centers for Disease Control and

Prevention (CDC) is initiating a study of

arsenic intake from bathing. EPA

requests comment on whether available

data on skin absorption and inhalation

indicate that these are significant

exposure routes that should be

considered in the risk assessment.

D. What is the Regulatory History for

Arsenic?

Regulation of arsenic has been the

subject of scientific debate that has

lasted for decades despite research and

scientific review. The controversy has

affected policy and regulatory decisions

for arsenic in drinking water from low,

environmental exposure.

1. Earliest U.S. Arsenic Drinking Water

Standards

In 1942 the U.S. Public Health Service

first established an arsenic drinking

water standard for interstate water

carriers at 0.05 mg arsenic per liter (mg/

L, or 50 μg/L), as measured with a

colorimetric method. The report did not

cite any reason for choosing that level,

but it defined ‘‘safety of water supplies’’

as ‘‘the danger, if any, is so small that

it cannot be discovered by available

means of observation (US Public Health

Service 1943).’’ In 1946, the Surgeon

General of the U.S. Public Health

Service noted that the American Water

Works Association had accepted the

1942 drinking water standards,

including the arsenic standard (U.S.

Public Health Service 1946). In 1962

(U.S. Public Health Service 1962) the

U.S. Public Health Service issued more

stringent drinking water standards for

arsenic of 0.01 mg/L (10 μg/L) for a

water supply in 42 CFR 72.205(b)(1) and

0.05 mg/L in 42 CFR 72.205(b)(2) as

grounds for rejection of a water supply,

as measured by the current edition of

Standard Methods for the Examination

of Water and Wastewater per 42 CFR

72.207(a).

The Safe Drinking Water Act of 1974

amended the Public Health Service Act

and specified that EPA set primary and

secondary drinking water standards. On

December 24, 1975 (40 FR 59566 at

59570; US EPA, 1975), EPA issued a

National Interim Primary Drinking

Water Regulation for arsenic in

§ 141.23(b) of 0.05 mg/L (50 μg/L),

effective 18 months later (§ 141.6).

Commenters recommended an MCL of

100 μg/L, saying there were no observed

adverse health effects (40 FR 59566 at

59576; US EPA, 1975). EPA noted longterm chronic effects at 300–2,750 μg/L,

but observed no illnesses in a California

study at 120 μg/L. Drinking 2 liters of

water a day containing arsenic at 50 μg/

L would provide approximately 10% of

total ingested arsenic from food and

water, estimated to be 900 μg/day. The

section on arsenic noted that arsenic has

been believed to be a carcinogen

‘‘[s]ince the early nineteenth century

* *; however evidence from animal

experiments and human experience has

accumulated to strongly suggest that

arsenicals do not produce cancer. One

exception is a report from Taiwan

* * *. The text goes on to note

occupational skin and lung cancer from

arsenic dust and skin cancer in England

from drinking water with 12 mg/L. (US

EPA, 1976 Appendix A).

2. EPA’s 1980 Guidelines

Scientific data at the time the 1980

Ambient Water Quality Guidelines were

formulated did not support a safe or

‘‘threshold’’ concentration for

carcinogens, so EPA’s public health

policy was

‘‘that the recommended concentration for

maximum protection of human health is

zero. In addition, the Agency presented a

range of concentrations corresponding to

incremental cancer risks of 10¥7 to 10¥5

(one additional case of cancer in populations

ranging from ten million to 100,000,

respectively) * * * [that did not necessarily

represent] an Agency judgement on an

‘acceptable’ risk level (45 FR 79318 at 79323,

US EPA, 1980).’’

In the November 28, 1980 Federal

Register document, using its then

current risk assessment approach

(assumed toxicity increased as a natural

logarithm linear function across

species), EPA set the Clean Water Act

surface water quality criterion for

arsenic at 2.2 nanograms (ng/L) (0.0022

μg/L) at an increased cancer risk of

10¥6. The criterion was to prevent skin

cancer in humans drinking

contaminated water and eating aquatic

organisms from those water bodies (45

FR 79318 at 79326). The 1980 Federal

Register notice indicated that drinking

water standards consider a range of

factors, including health effects,

technological and economic feasibility

of removal, and monitoring capability.

On the other hand the Clean Water Act

criteria of section 304(a)(1) ‘‘have no

regulatory significance under the

SDWA.’’ The Clean Water Act section

304(a)(1) criteria are more similar to the

health-based goals of the recommended

maximum contaminant levels (now

referred to as MCLGs), than to MCLs;

and differences in mandates ‘‘may result

in differences between the two

numbers.’’ (45 FR 79318 at 79320; US

EPA, 1980). In 1992, the Clean Water

Act criterion was recalculated based on

the updated cancer risk assessment in

EPA’s Integrated Risk Information

System (IRIS) database, to a level of

0.018 μg/L for arsenic at a 10¥6 cancer

risk (57 FR 60848; US EPA, 1992c).

3. Research and Regulatory Work

The 1980 National Academy of

Science (NAS) Volume III of ‘‘Drinking

Water and Health’’ report encouraged

EPA to research whether arsenic is

essential for humans, as demonstrated

in four studies of mammalian species.

The 1983 NAS Volume V report

projected that 0.05 mg/kg of total

arsenic may be a desirable level for

people, and 25 to 50 μg a day may be

required (as cited in 50 FR 46936 at

46960; US EPA, 1985b).

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38895

In 1983, EPA requested comment on

whether the arsenic MCL should

consider carcinogenicity, other health

effects, and nutritional requirements,

and whether MCLs are necessary for

separate valence states (e.g., arsenite vs.

arsenate) (48 FR 45502 at 45512; US

EPA, 1983). On November 13, 1985,

EPA proposed (50 FR 46936; US EPA,

1985b) a recommended maximum

contaminant level (RMCL), a nonenforceable health goal now known as

an MCLG, of 50 μg/L based on the 1983

NAS conclusion that 50 μg/L balanced

toxicity and possible essentiality and

provided ‘‘a sufficient margin of safety’’

(50 FR 46936 at 46960). EPA also

requested comment on alternate RMCLs

of 100 μg/L based on noncarcinogenic

effects (calculated from an animal study

and an uncertainty factor of 1000) and

0 μg/L based on carcinogenicity (50 FR

46936 at 46961). EPA chose not to base

the proposed RMCL on the animal study

because each dose group had only four

Rhesus monkeys. Also, at that time,

studies had ‘‘not detected increased

risks via drinking water in the USA’’ (50

FR 46936 at 46960). The 1985 proposed

drinking water regulation preamble

noted the 1980 excess cancer risk values

derived from the ambient water quality

criteria were based on skin cancer using

the 1968 Tseng et al. study (50 FR 46936

at 46961).

The June 19, 1986 amendments to the

Safe Drinking Water Act (SDWA; Public

Law 99–339) converted the 1975 interim

arsenic standard to a National Primary

Drinking Water Regulation (section

1412(a)(1)), subject to revision by 1989

(section 1412(b)(1)). Review of the

arsenic risk assessment issues caused

the Agency to miss the 1989 deadline

for proposing a revised NPDWR. As a

result of a citizen suit to enforce the

deadline, EPA entered into a consent

decree providing deadlines for issuing

the arsenic rule.

In 1988, EPA’s Risk Assessment

Forum issued the Special Report on

Ingested Inorganic Arsenic: Skin Cancer;

Nutritional Essentiality (EPA/625/3–87/

013), in part, to evaluate the validity of

applying skin cancer data from

Taiwanese studies (published in 1968

and 1977) in dose-response assessments

in the U.S. As described in the report,

the maximum likelihood estimate of risk

ranged from 3 × 10¥5 to 7 × 10¥5 for

a 70-kilogram person consuming 2 liters

of water per day contaminated with 1 μg

of arsenic per liter. Calculated at the 50

μg/L standard, the U.S. lifetime risk of

skin cancer ranged from 1 × 10¥3 to 3

× 10¥3, which means one to three skin

cancers would occur in a group of one

thousand people drinking water

containing arsenic at 50 μg/L. Existing

studies could not determine whether

arsenic was an essential nutrient.

After reviewing the scientific

evidence for carcinogenicity, EPA’s

Science Advisory Board (US EPA, 1989a

and b) stated in its August 1989 and

September 1989 reports that (1) the

animal studies suggesting arsenic is an

essential nutrient are not definitive; (2)

the skin changes seen in hyperkeratosis

may not always result in skin cancer; (3)

the 1968 Taiwan data demonstrate that

high doses of ingested arsenic can cause

skin cancer; (4) the Taiwan study is

inconclusive to determine cancer risk at

levels ingested in the United States

(U.S.); and (5) As (III) levels below 200–

250 μg per day may be detoxified. SAB

recommended that EPA set the MCL

using a non-linear dose-response (at

some low dose, arsenic would not be

toxic). The SAB report recommended

that EPA revise the risk assessment

based on dose of arsenic to target tissues

(the concentration of arsenic that

damages tissues, rather than the

concentration in water) and consider

detoxification.

The SAB also reviewed EPA’s April

12, 1991 Arsenic Research

Recommendations (US EPA, 1991c).

The final report provided SAB’s

recommendations (US EPA, 1992a) and

‘‘identified research needed to resolve

major uncertainties about inorganic

arsenic cancer risk’’ to evaluate if work

could be done in three to five years. It

noted that ‘‘important work can be done

within the time available. Although the

results from this work will not

completely resolve any issue, * * * the

results will likely significantly improve

the Agency’s ability to evaluate the risk.

* * * through improved knowledge of

arsenic metabolism and * * * as a

carcinogen.’’ The report reflected

uncertainty as to whether or not EPA

could obtain enough data to regulate

arsenic using a non-linear model, which

needed more information on how

arsenic induces cancer. The group noted

that it would take longer than five years

to develop an animal model to help

understand the toxicity of arsenic. SAB

recommended four short-term studies:

(a) Investigation of chromosome

damage, arsenic metabolites, and the

times cells are most susceptible to

arsenic, (b) study of human liver

capacity to add methyl groups to

arsenic, (c) identifying the species in

urine in several populations to look for

evidence of saturation of methylation

enzymes, and (d) comparing methylated

arsenic excreted in the U.S., Taiwan,

Mexico, and Argentina to consider the

effect of nutritional or genetic

differences on methylation capacity.

However, if time were not a factor, SAB

ranked developing an animal model of

arsenic-induced cancer as the first

priority.

In 1993 SAB reviewed EPA’s draft

‘‘Drinking Water Criteria Document on

Inorganic Arsenic (US EPA, 1993a).’’ In

1995, SAB reviewed the analytical

methods, occurrence estimate, treatment

technologies, and approach for

assigning costs in the regulatory impact

analysis (US EPA, 1995). Besides

highlighting previous SAB reviews of

1989, 1992, and 1994 on health effects,

the 1995 report recommended changes

to the practical quantitation limit

approach, use of occurrence data,

review of technologies, and support for

the decision tree, with some

reservations.

EPA held internal workgroup

meetings throughout 1994, addressing

risk assessment, treatment, analytical

methods, arsenic occurrence, exposure,

costs, implementation issues, and

regulatory options. EPA decided in early

1995 to defer the arsenic regulation in

order to better characterize health

effects and assess cost-effective removal

technologies for small utilities.

The 1996 amendments to SDWA

included a new statutory deadline for

the arsenic regulations, as discussed in

section II.A.

E. EPA’s Arsenic Research Plan

EPA held a workshop in March 1994

entitled ‘‘Workshop on Developing an

Epidemiology Research Strategy for

Arsenic in Drinking Water.’’ The cover

letter to the final report (US EPA,

1997b), dated April 14, 1997, notes that

EPA has been using the

recommendations to direct its research

directions. The report listed ten projects

and seventeen conclusions on exposure,

endpoints, study design and statistical

power, population selection, feasibility

of conducting a study in the U.S.,

international studies, importance of

developing biomarkers to measure

health effects of arsenic, and animal

studies.

In 1995, the Water Industry Technical

Action Fund (WITAF) ( funded by the

American Water Works Association,

National Association of Water

Companies, Association of Metropolitan

Water Agencies, National Rural Water

Association, and National Water

Resources Association), the AWWA

Research Foundation, and the

Association of California Water

Agencies (ACWA) sponsored an Expert

Workshop on Arsenic Research Needs

in Ellicott City, MD, May 31–June 2,

1995. The final report (AWWA et al.,

1995) identified research projects in

mechanisms, epidemiology, toxicology,

and treatment. It identified ten high

38896 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

priority projects which would need over

$3 million to fund, eleven medium

priority projects needing over $6

million, and ten low priority projects

costing over $9 million, that totaled over

$19 million in research needs.

Congress recognized the importance

of health effects research in regulating

arsenic, as demonstrated by the 1996

statutory requirement to develop a

research plan within 180 days ‘‘in

support of drinking water rulemaking to

reduce the uncertainty in assessing

health risks associated with exposure to

low levels of arsenic * * * (section

1412(b)(12)(A)(ii)). In the research plan

EPA recognized that ‘‘[t]he research

needs are broader than those that EPA

can address alone, and it is anticipated

that other entities will be involved in

conducting some of the needed research

(US EPA, 1998a).’’ (See section III.E.1.

on industry-funded research and the

arsenic research plan (at www.epa.gov/

ORD/WebPubs/final/arsenic.pdf) for

EPA-funded projects.) In December

1996, EPA submitted its draft research

plan for peer review by its Board of

Scientific Counselors’ (BOSC) Ad Hoc

Committee, and the committee met in

January 1997. The February 1998

Arsenic Research Plan addressed the

June 1997 comments from BOSC.

Major areas covered in the research

plan included studies to:

• Improve our qualitative and

quantitative assessment of the human

toxicity of arsenic;

• Understand mechanisms of arsenic

toxicity that may aid in extension of the

observed human findings when

extrapolation is required;

• Measure exposures of the US

population to arsenic from various

sources (particularly diet) to allow

better definition of cumulative

exposures to arsenic;

• Refine treatment technologies that

may better remove arsenic from water

supplies;

• Improve methods for analyzing and

monitoring arsenic in drinking water.

EPA also set priorities in the plan and

identified projects that met the short

term and long term criteria:

Short Term Criteria

1. Will the research improve the

scientific basis for risk assessments

needed for proposing a revised arsenic

MCL by January 1, 2000?

2. Will the research improve the

scientific basis for risk management

decisons needed for proposinig a

revised arsenic MCL by January 1, 2000?

Long Term Criteria

1. Will the research improve the

scientific basis for risk assessment and

risk management decisions needed to

review and develop future MCLs

beyond the year 2000?

2. Is the research essential to

improving our scientific understanding

of the health risks of arsenic?

The research plan included the

following priority topics for research

under the five major areas of

investigation supporting drinking water

rulemaking:

Exposure Analysis

• Arsenic speciation and

preservation: Improvements in

analytical methods to support water

treatment decisions.

• Measurement of background

exposures to arsenic in U.S. population,

particularly inorganic arsenic intake in

the U.S. diet.

• Development and evaluation of

biomarkers (e.g., species of arsenic in

urine) of exposures.

• Development of standard reference

material for arsenic in water, food,

urine, tissues.

Cancer Effects

• Further study of internal cancers

associated with arsenic exposures.

• Dose response data on

hyperkeratosis as a likely precursor to

skin cancer.

• Research on factors influencing

human susceptibility including age,

genetic characteristics and dietary

patterns.

• Metabolic and pharmacokinetic

studies that can identify dose dependent

metabolism.

• Mechanistic studies for arsenicinduced genotoxicity and

carcinogenicity.

Noncancer Effects

• Development of human doseresponse data for hyperkeratosis,

cardiovascular disease, neurotoxicity

and developmental effects.

• Development of additional health

effects and hazard identification data on

other non-cancer endpoints such as

diabetes and hematologic effects.

Risk Management Research

• Identification of limitations of

treatment technologies and impacts on

water quality.

• Development of treatment

technologies for small water systems.

• Development of data on cost and

performance capabilities of various

treatment options.

• Consideration of residuals

management issues, including disposal

options and costs.

Risk Assessment/Characterization

• Development of risk

characterizations to provide interim

support to States and local

communities.

• Development of predictive tools

and statistical models for assessing

bioavailability, interactions and doseresponse as better mass balance data

become available.

• Comprehensive assessment of

exposure levels and incorporation of

data into risk estimates for better

characterization of actual risks

associated with arsenic exposure.

• Comprehensive assessment of

arsenic mode of action provide a greater

understanding of biological mechanisms

and factors that may impact the shape

of a dose response curve.

• Comprehensive assessment of noncancer risks and consideration of

appropriate modeling tools for

quantitative estimation of non-cancer

risks.

• Comprehensive assessment of

human dose-response data for

hyperkeratosis, cardiovascular disease,

neurotoxicity and developmental

effects.

III. Toxic Forms and Health Effects of

Arsenic

A. What Are the toxic Forms of Arsenic?

Arsenic exists in several forms which

vary in toxicity and occurrence.

Accordingly, for this proposed

regulation, it is important to consider

those forms that can exert toxic effects

and to which people may be exposed.

For example, the metallic form of

arsenic (0 valence) is not absorbed from

the stomach and intestines and does not

exert adverse effects. On the other hand,

a volatile compound such as arsine

(AsH3) is toxic, but is not present in

water or food. Moreover, the primary

organic forms (arsenobetaine and

arsenocholine) found in fish and

shellfish seem to have little or no

toxicity (Sabbioni et al., 1991).

Arsenobetaine quickly passes out of the

body in urine without being

metabolized to other compounds

(Vahter, 1994). Arsenite (+3) and

arsenate (+5) are the most prevalent

toxic forms of inorganic arsenic that are

found in drinking water. However,

recovery of identified arsenic species in

vegetables, grains and oils has been

limited and difficult, so little is known

about types of species in these foods

(NRC, 1999).

In animals and humans, inorganic

pentavalent arsenic is converted to

trivalent arsenic that can be methylated

(i.e., chemically bonded to a methyl

group, which is a carbon atom linked to

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three hydrogen atoms) to mono-methyl

arsenic (MMA) and di-methyl arsinic

acid (DMA), which are organic

arsenicals. The primary route of

excretion for arsenic metabolites is in

the urine. Studies indicate that the

organic arsenicals MMA and DMA were

hundreds of times less likely to produce

genetic changes in animal cells than

inorganic arsenicals. Moreover, many

studies reported organic arsenicals to be

less reactive in tissues, to kill less cells,

and to be more easily excreted in urine

(NRC, 1999).

B. What Are the Effects of Acute

Toxicity?

Inorganic arsenic can exert toxic

effects after acute (short-term) or

chronic (long-term) exposure. From

human acute poisoning incidents, the

LD50 of arsenic has been estimated to

range from 1 to 4 mg/kg (Vallee et al.,

1960, Winship, 1984). This dose would

correspond to a lethal dose range of 70

to 280 mg for 50% of adults weighing

70 kg. At nonlethal, but high acute

doses, inorganic arsenic can cause

gastroenterological effects, shock,

neuritis (continuous pain) and vascular

effects in humans (Buchanan, 1962).

Such incidents usually occur after

accidental exposures. However,

sometimes high dose acute exposures

may be self-administered. For example,

inorganic arsenic is a component of

some herbal medicines and adverse

effects have been reported after use. In

one report of 74 cases (Tay and Seah,

1975), the primary signs were skin

lesions (92%), neurological (i.e., nerve)

involvement (51%), and

gastroenterological, hematological (i.e.,

blood) and renal (i.e., kidney) effects (19

to 23%). Although acute or short-term

exposures to high doses of inorganic

arsenic can cause adverse effects, such

exposures do not occur from public

water supplies in the U.S. at the current

MCL of 50 μg/L. EPA’s proposed

drinking water regulation addresses the

long-term, chronic effects of exposure to

low concentrations of inorganic arsenic

in drinking water.

C. What Cancers Are Associated With

Arsenic?

Inorganic arsenic is a multi-site

human carcinogen by the drinking water

route. Asian, Mexican and South

American populations with exposures

to arsenic in drinking water generally at

or above several hundred micrograms

per liter are reported to have increased

risks of skin, bladder, and lung cancer.

The current evidence also suggests that

the risks of liver and kidney cancer may

also be increased following exposures to

inorganic forms of arsenic. The weight

of evidence for ingested arsenic as a

causal factor of carcinogenicity is much

greater now than a decade ago, and the

types of cancer occurring as a result of

ingesting inorganic arsenic have even

greater health implications for U.S. and

other populations than the occurrence

of skin cancer alone. (Until the late

1980s skin cancer had been the cancer

classically associated with arsenic in

drinking water.) Epidemiologic studies

(e.g., of people) provide direct data on

arsenic risks from drinking water at

exposure levels much closer to those of

regulatory concern than environmental

risk assessments based on animal

toxicity studies.

1. Skin Cancer

Early reports linking inorganic arsenic

contamination of drinking water to skin

cancer came from Argentina (Neubauer,

1947, reviewing studies published as

early as 1925) and Poland (Geyer, 1898,

as reported in Tseng et al., 1968).

However, the first studies that observed

dose-dependent effects of arsenic

associated with skin cancer came from

Taiwan (Tseng et al., 1968; Tseng,

1977). These studies focused EPA’s

attention on the health effects of

ingested arsenic. Physicians physically

examined over 40,000 residents from 37

villages and 7500 residents exposed to

0.017 mg/L arsenic ( reference group).

The study population was divided into

three groups based on exposure to

inorganic arsenic (0 to 0.29, 0.30 to 0.59

and ≥0.60 mg of inorganic As/Liter)

measured at the village level. A doseand age-related increase of arsenicinduced skin cancer among the villagers

was noted. No skin cancers were

observed in the low arsenic reference

areas. The 1999 NRC report noted that

the ‘‘primary limitation of this study

* * * was the lack of detail’’ reported,

such as grouping individuals into

‘‘broad exposure groups’’ (rather than

grouping into 37 village exposures).

This limits the usefulness of these

studies. However, these Tseng reports

and other corroborating studies such as

those by Albores et al. (1979) and

Cebrian et al. (1983) on drinking water

exposure and exposures to inorganic

arsenic in medicines (Cuzick et al.,

1982) and in pesticides (Roth, 1956) led

the EPA, using skin cancer as the

endpoint, to classify inorganic arsenic

as a human carcinogen (Group A) by the

oral route (US EPA, 1984).

2. Internal Cancers

Exposure to inorganic arsenic in

drinking water has also been associated

with the development of internal

cancers. ‘‘No human studies of

sufficient statistical power or scope

have examined whether consumption of

arsenic in drinking water at the current

MCL results in an increased incidence

of cancer or noncancer effects (NRC,

1999, pg. 7).’’

Chen et al. (1985) used standardized

mortality ratios (SMRs) to evaluate the

association between ingested arsenic

and cancer risk in Taiwan. (SMRs, ratios

of observed to expected deaths from

specific causes, are standardized to

adjust for differences in the age

distributions of the exposed and

reference populations.) The authors

found statistically significant increased

risks of mortality for bladder, kidney,

lung, liver and colon cancers. A

subsequent mortality study in the same

area of Taiwan found significant doseresponse relationships for deaths from

bladder, kidney, skin, and lung cancers

in both sexes and from liver and

prostate cancer for males. They also

found increases in peripheral and

cardiovascular diseases but not in

cerebrovascular accidents (Wu et al.,

1989). There are several corroborating

reports of the increased risk of cancers

of internal organs from ingested arsenic

including two from two South American

countries. In Argentina, significantly

increased risks of death from bladder,

lung and kidney cancer were reported

(Hopenhayn-Rich et al., 1996; 1998). In

a population of approximately 400,000

in northern Chile, Smith et al. (1998)

found significantly increased risks of

bladder and lung cancer mortality.

There have only been a few studies of

inorganic arsenic exposure via drinking

water in the U.S., and most have not

considered cancer as an endpoint.

People have written EPA asking that the

new MCL be set considering that these

U.S. studies have not seen increases in

cancers at the low levels of arsenic

exposure in U.S. drinking water.

Optimally, low-exposure arsenic studies

involve long-term residency (20–40

years with known drinking water

arsenic exposure), access to health

records, populations large enough to

detect statistically significant increases

in cancers and other health endpoints,

and limited use of multiple sources of

water (bottled, filtered, beverages, food

prepared outside the home).

Recently, Lewis et al. (1999)

conducted a mortality study of a

population in Utah whose drinking

water contained relatively low

concentrations of arsenic (averaged 18–

191 μg/L). They reported no significant

increase in bladder or lung mortality.

They did report a statistically significant

dose-response for an increased risk of

prostate cancer mortality. Smoking is an

established risk factor for bladder and

lung cancer, and inorganic arsenic

38898 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

behaves as a comutagen even though it

is not mutagenic alone (NRC, 1999, pg.

200). It is possible that inorganic arsenic

potentiates other risk factors for these

cancers. This potential role is consistent

with the NRC, 1999 view that arsenic’s

mode of action may be to interfere with

cell ‘‘housekeeping’’ functions that

normally repair genetic damage and

ensure that damaged cells die

(programmed cell death) rather than

reproduce (see section III.D.2. below).

D. What Non-Cancer Effects Are

Associated With Arsenic?

A large number of adverse

noncarcinogenic effects have been

reported in humans after exposure to

drinking water highly contaminated

with inorganic arsenic. The earliest and

most prominent changes are in the skin,

e.g., hyperpigmentation and keratoses

(calus-like growths). Other effects that

have been reported include alterations

in gastrointestinal, cardiovascular,

hematological (e.g., anemia),

pulmonary, neurological,

immunological and reproductive/

developmental function (ATSDR, 1998).

The most common symptoms of

inorganic arsenic exposure appear on

the skin and occurr after 5–15 years of

exposure equivalent to 700 μg/day for a

70 kg adult, or within 6 months to 3

years at exposures equivalent to 2,800

μg/day for a 70 kg adult (pg. 131 NRC,

1999). They include alterations in

pigmentation and the development of

keratoses which are localized primarily

on the palms of the hands, the soles of

the feet and the torso. The presence of

hyperpigmentation and keratoses on

parts of the body not exposed to the sun

is characteristic of arsenic exposure

(Yeh, 1973, Tseng, 1977). The same

alterations have been reported in

patients treated with Fowler’s solution

(1% potassium arsenite; Cuzick et al.,

1982), used for asthma, psoriasis,

rheumatic fever, leukemia, fever, pain,

and as a tonic (WHO 1981 and NRC

1999).

Chronic exposure to inorganic arsenic

is often associated with alterations in

gastroenterological (GI) function. For

example, noncirrhotic hypertension is a

relatively specific, but not commonly

found manifestation in inorganic

arsenic-exposed individuals and may

not become a clinical observation until

the patient demonstrates GI bleeding

(Morris et al., 1974; Nevens et al., 1990).

Physical examination may reveal spleen

and liver enlargement, and

histopathological examination of tissue

specimens may demonstrate periportal

fibrosis (Morris et al., 1974; Nevens et

al., 1990; Guha Mazumder et al., 1997).

There have been a few reports of

cirrhosis after inorganic arsenic

exposure, but the authors of these

studies did not determine the subjects’

alcohol consumption (NRC 1999).

Development of peripheral vascular

disease (hardening of the arteries to the

arms and legs, that can cause pain,

numbness, tingling, infection, gangrene,

and clots) after inorganic arsenic

exposure has also been reported. In

Taiwan, blackfoot disease (BFD, a severe

peripheral vascular insufficiency which

may result in gangrene of the feet and

other extremities) has been the most

severe manifestation of this effect. Tseng

(1977) reported over 1,000 cases of BFD

in the arsenic study areas of Taiwan.

Less severe cases of peripheral vascular

disease have been described in Chile

(Zaldivar et al., 1974) and Mexico

(Cebrian, 1987). In a Utah study,

increased SMRs for hypertensive heart

disease were noted in both males and

females after exposure to inorganic

arsenic-contaminated drinking water

(Lewis et al., 1999). These reports link

exposure to inorganic arsenic effects on

the cardiovascular system.

Studies in Taiwan (Lai et al., 1994)

and Bangladesh (Rahman et al., 1998)

found an increased risk of diabetes

among people consuming arseniccontaminated water. Two Swedish

studies found an increased risk of

mortality from diabetes among those

occupationally exposed to arsenic

(Rahman and Axelson, 1995; Rahman et

al., 1998).

Although peripheral neuropathy

(numbness, muscle weakness, tremors,

ATSDR 1998) may be present after

exposure to short-term, high doses of

inorganic arsenic (Buchanan, 1962; Tay

and Seah, 1975), there are no studies

that definitely document this effect after

exposure to levels of less than levels

(<50 μg/L) of inorganic arsenic in

drinking water. Hindmarsh et al. (1977)

and Southwick et al. (1983) have

reported limited evidence of peripheral

neuropathy in Canada and the U.S.,

respectively, but it was not reported in

studies from Taiwan, Argentina or Chile

(Hotta, 1989, as cited by NRC 1999).

There have been a few, scattered

reports in the literature that inorganic

arsenic can affect reproduction and

development in humans (Borzysonyi et

al., 1992; Desi et al., 1992; Tabacova et

al., 1994). After reviewing the available

literature on arsenic and reproductive

effects, the National Research Council

panel (NRC 1999) wrote that ‘‘nothing

conclusive can be stated from these

studies.’’

Based on the studies mentioned in

this section, it is evident that inorganic

arsenic contamination of drinking water

can cause dermal and internal cancers,

affect the GI system, alter cardiovascular

function, and increase risk of diabetes,

based on studies of people exposed to

drinking water well above the current

arsenic MCL. EPA’s MCL is chosen to be

protective of the general population

within an acceptable risk range, not at

levels at which adverse health effects

are routinely seen (see section III.F.7. on

risk considerations).

E. What Are the Recent Developments in

Health Effects Research?

1. Funding of Health Effects Research

As mentioned earlier in section II.A.,

Congress recognized that we needed

more research to determine the health

effects at low levels of arsenic (below

the observed health effects and below 50

μg/L). On December 6, 1996, EPA issued

a Federal Register notice (61 FR 64739;

US EPA, 1996e) asking for public

comment on four arsenic health

research topics to fund research projects

with $2 million from EPA

appropriations and $1 million in funds

raised by water industry groups (US

EPA, 1996d). In addition, the Office of

Research and Development’s (ORD’s)

Board of Scientific Counselors (BOSC)

peer reviewed the draft research topics

and the arsenic research plan. In the fall

of 1997, EPA and the industry partners

funded their respective choices for

arsenic research, after having the

applications peer reviewed. EPA issued

three grants for the following research:

Dose Response of Skin Keratoses and

Hyper-Pigmentation, Arsenic

Glutathione Interactions and Skin

Cancer, and Cellular Redox Status. The

water industry groups awarded two

contracts, studying Contribution of

Arsenic From Dietary Sources and

Tumor Studies in Mice.

2. Expert Panel on Arsenic

Carcinogenicity

As part of the Integrated Risk

Information System (IRIS) update effort,

EPA sponsored an ‘‘Expert Panel on

Arsenic Carcinogenicity: Review and

Workshop’’ in May 1997 (US EPA,

1997d). The panel evaluated existing

data to comment on arsenic’s

carcinogenic mode of action and the

effect on dose-response extrapolations.

The panel noted that arsenic

compounds have not formed DNA

adducts (i.e., bound to DNA) nor caused

point mutations. Trivalent inorganic

forms inhibit enzymes, but arsenite and

arsenate do not affect DNA replication.

The panel discussed several modes of

action, concluding that arsenic

indirectly affects DNA, inducing

chromosomal changes. The panel

thought that arsenic-induced

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chromosomal abnormalities could

possibly come from errors in DNA

repair and replication that affect gene

expression; that arsenic may increase

DNA hypermethylation and oxidative

stress; that arsenic may affect cell

proliferation (cell death appears to be

nonlinear); and that arsenic may act as

a co-carcinogen. Arsenite causes cell

transformation but not mutation of cells

in culture. It also induces gene

amplification (multiple copies of DNA

sequences) in a way which suggests

interference with DNA repair or cell

control instead of direct DNA damage.

The panel noted that all identified

modes of action support a nonlinear

dose-response curve, that few data

supports any one mode as most

important, and that more than one mode

of action may be operating. At low doses

the slope of the dose response would

decrease, and at very low doses ‘‘might

effectively be linear but with a very

shallow slope, probably

indistinguishable from a threshold.’’

In terms of implications for the risk

assessment, the panel noted that risk per

unit dose estimates from human studies

can be biased either way. For the

Taiwanese study, the ‘‘* * * biases

associated with the use of average doses

and with the attribution of all increased

risk to arsenic would both lead to an

overestimation of risk (US EPA, 1997d,

page 31).’’ While health effects are most

likely observed in people getting high

doses, the effects are assigned to the

average dose of the exposure group.

Thus, risk per unit dose estimated from

the average doses would lead to an

overestimation of risk (US EPA, 1997d,

page 31).

3. NAS Review of EPA’s Risk

Assessment

In 1997, at EPA’s request, the National

Academy of Sciences’ (NAS)

Subcommittee on Arsenic of the

Committee on Toxicology of the

National Research Council (NRC) met.

Their charge was to review EPA’s

assessments of arsenic. The NAS/NRC

Subcommittee finished their work in

March 1999 (The report can be viewed

from the National Academy Press

website: www.nap.edu/books/

0309063337/html/index.html). The

detailed discussion of their work is in

section III.F. In general, the NRC report

confirms and extends concerns about

human carcinogenicity of drinking

water containing arsenic and offers

perspective on dose-response issues and

needed research. For the decisions in

this regulation, the EPA has relied upon

the NRC report as presenting the best

available, peer reviewed science as of its

completion and has augmented it with

more recently published, peer reviewed

information. Further work on the risk

assessment will also be done before the

final rule is issued to analyze the risks

of internal cancers. The NRC provided

risk numbers for bladder cancer using

the Agency’s approach. The NRC report

noted that ‘‘some studies have shown

that excess lung cancer deaths attributed

to arsenic are 2–5 fold greater than the

excess bladder cancer deaths. * * *

(NRC, 1999, pg. 8).’’ The NRC

recommended that EPA analyze risks of

internal cancers both separately and

combined. Peer-reviewed quantitative

analysis of lung tumor risk is expected

to be available for consideration in the

final rulemaking. Meanwhile, this

proposal, in a ‘‘what if’’ analysis

(discussed in section X.B), estimates the

potential monetary benefits that would

result if the lung cancer and bladder

cancer risks were the same, which

would be the case if the excess lung

cancer deaths actually were 2- to 5-fold

greater than the excess bladder cancer

deaths.

4. May 1999 Utah Mortality Study

EPA scientists conducted an

epidemiological study of 4,058

Mormons exposed to arsenic in drinking

water in seven communities in Millard

County, Utah (Lewis et al., 1999). The

151 samples from their public and

private drinking water sources had

arsenic concentrations ranging from 4 to

620 μg/L with seven mean (arithmetic

average) community exposure

concentrations of 18 to 191 μg/L and all

seven community exposure medians

(mid-point of arsenic values) <200 μg/L.

Observed causes of death in the study

group (numbering 2,203) were

compared to those expected from the

same causes based upon death rates for

the general white male and female

population of Utah. Several factors

suggest that the study population may

not be representative of the rest of the

United States. The Mormon church, the

predominant religion in Utah, prohibits

smoking and consumption of alcohol

and caffeine. Utah had the lowest

statewide smoking rates in the U.S. from

1984 to 1996, ranging from 13 to 17%.

Mormon men had about half the cancers

related to smoking (mouth, larynx, lung,

esophagus, and bladder cancers) as the

U.S. male population from 1971 to 1985

(Lyon et al., 1994). The Utah study

population was relatively small (∼4,000

persons) and primarily English,

Scottish, and Scandinavian in ethnic

background.

While the study population males had

a significantly higher risk of prostate

cancer mortality, females had no

significantexcess risk of cancer

mortality at any site. Millard County

subjects had higher mortality from

kidney cancer, but this was not

statistically significant. Both males and

females in the study group had less risk

of bladder, digestive system and lung

cancer mortality than the general Utah

population. The Mormon females had

lower death rates from breast and female

genital cancers than the State rate.

These decreased death rates were not

statistically significant.

Although deaths due to hypertensive

heart disease were roughly twice as high

as expected in both sexes, increases in

death did not relate to increases in dose,

calculated as the years of exposure

times the median arsenic concentration.

The Utah data indicate that heart

disease should be considered in the

evaluation of potential benefits of U.S.

regulation. Vascular effects have also

been reported as an effect of arsenic

exposure in studies in the U.S. (Engel et

al. 1994), Taiwan (Wu et al., 1989) and

Chile (Borgono et al., 1977). The overall

evidence indicating an association of

various vascular diseases with arsenic

exposure supports consideration of this

endpoint in evaluation of potential

noncancer health benefits of arsenic

exposure reduction.

5. 1999 Review of Health Effects

Tsai et al. (1999) estimated

standardized mortality ratios (SMR’s)

for 23 cancer and non-cancer causes of

death in women and 27 causes of death

in men in an area of Taiwan with

elevated arsenic exposures (Tsai, et al.,

1999). The SMRs in this study are an

expression of the ratio between deaths

that were observed in an area with

elevated arsenic levels and those that

were expected to occur, compared to

both the mortality of populations in

nearby areas without elevated arsenic

levels and to the national population.

Drinking water (250–1,140 μg/L) and

soil (5.3–11.2 mg/kg) in the Tsai (1999)

population study had high arsenic

content. There are, of course, possible

differences between the population and

health care in Taiwan and the United

States; and arsenic levels in the U.S. are

not generally as high as they were in the

study area of Taiwan. However, the

study gives an indication of the types of

health effects that may be associated

with arsenic exposure via drinking

water. The study reports a high

mortality rate (SMR > 3) for both sexes

from bladder, kidney, skin, lung, and

nasal cavity cancers and for vascular

disease. Females also had high

mortalities for laryngeal cancer.

The SMRs calculated by Tsai (1999)

used the single cause of death noted on

the death certificates. Many chronic

38900 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

diseases, including some cancers, are

not generally fatal. Consequently, the

impact indicated by the SMR in this

study may underestimate the total

impact of these diseases. The causes of

death reported in this study are

consistent with what is known about the

adverse effects of arsenic. Tsai et al.

(1999) identified ‘‘bronchitis, liver

cirrhosis, nephropathy, intestinal

cancer, rectal cancer, laryngeal cancer,

and cerebrovascular disease’’ as

possibly ‘‘related to chronic arsenic

exposure via drinking water,’’ which

had not been reported before. In

addition, people in the study area were

observed to have nasal cavity and larynx

cancers not caused by occupational

exposure to inhaled arsenic.

6. Study of Bladder and Kidney Cancer

in Finland

Kurttio et al. (1999) conducted a casecohort design study of 61 bladder and

49 kidney cancer cases and 275 controls

to evaluate the risk of these diseases

with respect to arsenic drinking water

concentrations. In this study the median

exposure was 0.1 μg/L, the maximum

reported was 64 μg/L, and 1% of the

exposure was greater than 10 μg/L. The

authors reported that very low

concentrations of arsenic in drinking

water were significantly associated with

being a case of bladder cancer when

exposure occurred 2–9 years prior to

diagnosis. Arsenic exposure occurring

greater than 10 years prior to diagnosis

was not associated with bladder cancer

risk. Arsenic was not associated with

kidney cancer risk even after

consideration of a latency period.

F. What Did the National Academy of

Sciences/National Research Council

Report?

1. The National Research Council and

Its Charge

Due to controversy surrounding the

risk assessment of inorganic arsenic,

EPA asked the National Research

Council (NRC) to do the following: (1)

Review EPA’s characterization of

potential human health risks from

ingestion of inorganic arsenic in

drinking water; (2) review the available

data on the carcinogenic and

noncarcinogenic effects of inorganic

arsenic; (3) review the data on the

metabolism, kinetics and mechanism(s)/

mode(s) of action of inorganic arsenic;

and (4) identify research needs to fill

data gaps. To accomplish this task, NRC

convened a panel of scientific experts

with backgrounds in chemistry,

toxicology, genetics, epidemiology,

nutrition, medicine, statistics and risk

assessment. In addition to the general

expertise of the panel members, many

had conducted research on inorganic

arsenic. NRC identified the thirteen

scientists with ‘‘diverse perspectives

and technical expertise’’ that peer

reviewed the draft report. The report

noted that ‘‘EPA did not request, nor did

the subcommittee endeavor to provide,

a formal risk assessment for arsenic in

drinking water (NRC, 1999).’’

2. Exposure

Arsenic is naturally occurring and

ubiquitously distributed in the earth’s

surface. Because of this, the general

population is exposed to low levels of

arsenic through the food supply. The

NRC report provides FDA market basket

data for inorganic arsenic intake by age

group which, along with similar data for

water intake, will permit

communication of total exposure

estimates of the general population by

age group. The assumption is made in

the FDA data that, for fish and seafood,

inorganic arsenic is 10% of total arsenic.

This 10% assumption is acknowledged

to be conservative and has been adopted

for public health protection so as not to

underestimate the contribution from

fish and seafood. Likewise, the 2 L/day

assumption of adult drinking water

intake does not represent intake by the

average person; rather it represents

intake of a person in the 90th percentile.

3. Essentiality

The NRC report examined the

question of essentiality of arsenic in the

human diet. It found no information on

essentiality in humans and only data in

experimental animals suggesting growth

promotion (arsenicals are fed to

livestock for this reason). Inorganic

arsenic has not been found to be

essential for human well-being or

involved in any required biochemical

pathway. Given this and the fact that

arsenic occurs naturally in food,

consideration of essentiality is not

necessary for public health decisions

about water.

4. Metabolism and Disposition

Data from humans show that

inorganic arsenic is readily absorbed

and transported through the body. It has

a half-life in the body of approximately

four days and is primarily excreted in

the urine. If a human is exposed to the

inorganic arsenate form (+5 valence),

the arsenite will be reduced to arsenite

(+3). Some of the arsenite will be

sequentially methylated to form

monomethylarsonic acid (MMA) and

dimethylarsinic acid (DMA). This

methylation process decreases acute

toxicity and facilitates excretion from

the body. Individuals and populations

vary in their metabolism of arsenic.

Such variations may be due to genetic

differences, species and dose of

inorganic arsenic ingested, nutrition,

disease and possibly other factors.

Whether these methylated products

(MMA and DMA) play a role in the

development of cancer and noncancer

endpoints is unknown at the present

time (NRC, 1999). The NRC report

recommended that experiments be

conducted on the factors affecting

interspecies differences in inorganic

arsenic toxicity including use of human

tissue when available.

5. Human Health Effects and Variations

in Sensitivity

The NRC panel concluded that there

is sufficient evidence that chronic

ingestion of inorganic arsenic causes

bladder, lung and skin cancers and

adverse noncancer effects on the

cardiovascular systems, mainly from

studies exposed to ‘‘several hundred

micrograms per liter. Few data address

the degree of cancer risk at lower

concentrations of ingested arsenic (NRC,

1999, pg. 130).’’ The Utah study (Lewis

et al., 1999), published after the NRC

report, indicates that cardiovascular

effects can occur at lower exposures

than those seen in the studies available

for the NRC report. At the present time,

the NRC report indicates that there is

insufficient evidence to judge whether

inorganic arsenic can affect

reproduction or development in

humans. However, inorganic arsenic can

pass through the placenta (Concha et al.,

1998), and developmental toxicity needs

investigation. In animal studies,

intraperitoneal (injection into the

abdominal cavity) administration of

inorganic arsenic can cause

malformations, and oral dosing has been

reported to alter fetal growth and

viability. The NRC report recommended

additional studies to characterize the

dose-response curve for inorganic

arsenic-induced cancer and noncancer

health endpoints. They also stated that

the reported beneficial effects of

inorganic arsenic in animals should be

carefully monitored. In addition, the

potential effects of inorganic arsenic on

human reproduction should be

investigated.

There are many factors (genetics, diet,

metabolism, health and sex) that may

affect a human’s response to inorganic

arsenic exposure. For example,

reduction in methylation of inorganic

arsenic methylation can cause humans

to retain more arsenic in their tissues.

The retention of a greater arsenic load

could place a person at a greater risk.

The NRC report (1999) recommended

that various factors that have the ability

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38901

to alter a human’s response to inorganic

arsenic exposure be carefully examined.

Specifically, these studies should focus

on the extent of human variability with

respect to metabolism, tissue deposition

and excretion under different

environmental conditions.

Humans are variable in their

metabolic processing of inorganic

arsenic, and internal dose will vary from

person to person because of this as well

as because of diet, nutritional status,

lifestyle, and health status. Human

variability also exists in response

characteristics (susceptibility). The full

quantitative extent of this variability is

not known. For instance, men are more

susceptible than women to bladder

cancer throughout the world even

though bladder cancer rates vary from

region to region. We do not know

whether arsenic may have a greater

effect at different ages (e.g., infants v.s.

adults).

6. Modes of Action

Knowledge of a ‘‘mode of action’’

means that data are available to describe

the key events at the cellular and/or

subcellular level that lead to the

development of the cancer or noncancer

endpoint. A number of potential modes

of carcinogenic action have been

proposed for arsenic, with varying

degrees of supporting data. The key

events in the cancer process caused by

arsenic exposure are not known.

Nevertheless, the data are sufficient to

support the conclusion of the NRC

report and the EPA 1997 expert panel

workshop report that: ‘‘Arsenic

exposure induces chromosomal

abnormalities without direct reaction

with DNA (US EPA, 1997d).’’

There is strong evidence against a

mode of action for inorganic arsenic

involving direct reaction with DNA.

One of the hallmarks of direct DNA

reactivity is multi-species carcinogenic

activity. For arsenic, long-term

bioassays for carcinogenic activity in

rats, mice, dogs, and monkeys have been

uniformly negative (Furst, 1983). The

kinds of genetic alterations seen in both

in vivo and in vitro studies of arsenic

effects are at the level of loss and

rearrangement of chromosomes; these

are results of errors of ‘‘cellular

housekeeping’’ either in DNA repair or

in chromosome replication. The NRC

and EPA expert panel (US EPA, 1997d)

reports examined several lines of

evidence for various modes of action

that might be operative. These included

changes in DNA methylation patterns

that could change gene expression and

repair, oxidative stress, potentiation of

effects of mutations caused by other

agents, cell proliferative effects, and

interference with normal DNA repair

processes. Further examination in both

of these reports of dose-response shapes

associated with these effects led to the

conclusion that they involve processes

that have either thresholds of dose at

which there would be no response or

sublinearity of the dose response

relationship (response decreasing

disproportionately as dose decreases).

The NRC report concluded: ‘‘For

arsenic carcinogenicity, the mode of

action has not been established, but the

several modes of action that are

considered plausible (namely, indirect

mechanisms of mutagenicity) would

lead to a sublinear dose-response curve

at some point below the point at which

a significant increase in tumors is

observed. * * * However, because a

specific mode (or modes) of action has

not yet been identified, it is prudent not

to rule out the possibility of a linear

response.’’

The NRC report noted that in certain

in vitro studies of human and animal

cells, genotoxic effects have been shown

to occur at submicromolar

concentrations of arsenite that are

similar to concentrations found in urine

of humans ingesting water at the current

MCL. This emphasizes the potentially

low margin of exposure (health effects

observed at concentrations eight times

above the MCL) for arsenic in water at

the current MCL.

For noncancer effects, inhibition of

cellular respiration in mitochondria by

arsenic may be the focal point of its

toxicity. In addition, inorganic arsenic

causes oxidative stress that could play

a role in the development of adverse

health effects. The NRC report (1999)

recommended that biomarkers of

inorganic arsenic exposure and cancer

appearance be thoroughly studied. Such

data might better characterize the doseresponse effects of inorganic arsenic at

lower exposure levels. For noncancer

effects, a greater understanding of

arsenic’s effects on cellular respiration

and subsequent effects of methylation

and oxidative stress are needed (NRC,

1999).

NRC recommended several mode of

action studies, using biomarkers, to help

predict the shape of the dose-response

curve for cancer and non-cancer

endpoints. NRC concluded that ‘‘

* * *Additional epidemiological

evaluations are needed to characterize

the dose-response relationship for

arsenic-associated cancer and noncancer endpoints, especially at low

doses.’’

7. Risk Considerations

The NRC study used the results of

epidemiological, (i.e., human) studies;

research on the mode of action, and

information about factors affecting

sensitivity to arsenic to project to risks

to the U.S. population. The numerical

estimation of risk in the NRC report has

several features to consider. The range

of drinking water levels associated with

health endpoints in the available studies

is generally hundreds of ppb which is,

however, within a factor of 10 of the

existing standard of 50 ppb. Because of

uncertainty about the shape of the doseresponse relationship below this range

of observed responses, the NRC report

used the approach of the 1996 EPA

proposed carcinogen risk assessment

guidelines (US EPA, 1996b). For the

male bladder cancer deaths which were

emphasized in the report, NRC used a

lower limit on the dose associated with

a 1% (1 in 100) cancer response, and the

LED01 is estimated to be ∼400 ppb. This

is a point of departure for extrapolating

to exposure levels outside the range of

observed data based on inference.

Consistent with the proposed revisions

to the Guidelines for Cancer Risk

Assessment, the report shows both a

linear extrapolation and a margin of

exposure extrapolation (difference

between the point of departure and

selected exposure). Because current data

on potential modes of action are

supportive of sub-linear extrapolations,

the linear approach could overestimate

risk at low doses. However, EPA

believes that within the several-fold

range (10x) just below the point of

departure, this should make little

difference. EPA’s scientists note that it

makes an increasing difference as dose

decreases, and the difference results in

an overestimate of risk at lower

exposures. With a straight-line

extrapolation from the point of

departure, the report estimated risk to

be 1.0 to 1.5 × 10¥3 at the current MCL

of 50 ppb and the margin of exposure

to be less than 8.

As described further in section X.A.,

EPA used parts of NRC’s risk analysis

and applied U.S. water consumption,

weights, and estimate of population

exposed to arsenic to model the U.S.

population risk. In selecting the

proposed MCL, EPA considered the

uncertainties of the quantitative doseresponse assessment for inorganic

arsenic’s health effects, particularly the

possible nonlinearity of the doseresponse and multiple cancer risks.

Given the current outstanding questions

about human risk at low levels of

exposure, decisions about safe levels are

public health policy judgments.

8. Risk Characterization

In 1983 the National Academy of

Sciences (NAS, 1983) defined risk

38902 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

assessment as containing four steps:

hazard identification, dose-response

assessment, exposure assessment, and

risk characterization. Risk

characterization is the process of

estimating the health effects based on

evaluating the available research,

extrapolating to estimate health effects

at exposure levels, and characterizing

uncertainties. In risk management,

regulatory agencies such as EPA

evaluate alternatives and select the

regulatory action. Risk management

considers ‘‘political, social, economic,

and engineering information’’ using

value judgments to consider ‘‘the

acceptability of risk and the

reasonableness of the costs of control

(NAS, 1983).’’

Unlike most chemicals, there is a

large data base on the effects of arsenic

on humans. Inorganic arsenic is a

human poison, and oral or inhalation

exposure to the chemical can induce

many adverse health conditions in

humans. Specifically oral exposure to

inorganic arsenic in drinking water has

been reported to cause many different

human illnesses, including cancer and

noncancer effects, as described in

Section III. The NRC panel (1999)

reviewed the inorganic arsenic health

effects data base. The panel members

concluded that the studies from Taiwan

provided the current best available data

for the risk assessment of inorganic

arsenic-induced cancer. (There are

corroborating studies from Argentina

and Chile.) They obtained more detailed

Taiwanese internal cancer data and

modeled the data using the multistage

Weibull model and a Poisson regression

model. Three Poisson data analyses

showed a 1% response level of male

bladder cancer at approximately 400 μg

of inorganic arsenic/L. The 1% level

was used as a Point of Departure (POD)

for extrapolating to exposure levels

outside the range of observed data.

For an agent that is either acting by

reacting directly with DNA or whose

mode of action has not been sufficiently

characterized, EPA’s public health

policy is to assume that dose and

response will be proportionate as dose

decreases (linearity of the extrapolated

dose-response curve). This is a science

policy approach to provide a public

health conservative assessment of risk.

The dose-response relationship is

extrapolated by taking a straight line

from the POD rather than by attempting

to extend the model used for the

observed range. This approach was

adopted by the NRC report which

additionally noted that using this

approach for arsenic data provides

results with alternative models that are

consistent at doses below the observed

range whereas extending the alternative

models below the observed range gives

inconsistent results. Drawing a straight

line from the POD to zero gives a risk

of 1 to 1.5 per 1,000 at the current MCL

of 50 μg/L. Since some studies show

that lung cancer deaths may be 2- to 5-

fold higher than bladder cancer deaths,

the combined cancer risk could be even

greater. The NRC panel also noted that

the MCL of 50 μg/L is less than 10-fold

lower than the 1% response level for

male bladder cancer. Based on its

review, the consensus opinion of the

NRC panel was that the current MCL of

50 μg/L does not meet the EPA’s goal of

public-health protection. Their report

recommended that EPA lower the MCL

as soon as possible.

IV. Setting the MCLG

A. How Did EPA Approach It?

For the decisions in this regulation,

the EPA has relied upon the NRC report

as presenting the best available, peer

reviewed science as of its completion

and has augmented it with more

recently published, peer reviewed

information. EPA used the 1999 NRC

report and other published scientific

papers to characterize the potential

health hazards of ingested inorganic

arsenic. As NRC (1999) noted, DMA

may enhance the carcinogenicity of

other chemicals, but more data are

needed. Based on current knowledge,

the organic forms of arsenic in fish and

shellfish do not appear to present a

significant risk to humans. The overall

weight of evidence indicates that the

inorganic arsenate and arsenite forms

found in drinking water are responsible

for the adverse health effects of ingested

arsenic. EPA focused its risk assessment

on the carcinogenic effects of inorganic

arsenic (the forms found in drinking

water sources).

A factor that could modify the degree

of individual response to inorganic

arsenic is its metabolism. There is

ample evidence (NRC, 1999) that the

quantitative patterns of inorganic

arsenic methylation vary considerably

and that the extent of this variation is

unknown. It is certainly possible that

the metabolic patterns of people affect

their response to inorganic arsenic.

There are studies underway in

humans and experimental animals

under the EPA research plan and other

sponsorships. Over the next several

years these will provide better

understanding of the mode(s) of

carcinogenic action of arsenic,

metabolic processes that are important

to its toxicity, human variability in

metabolic processes, and the specific

contributions of various food and other

sources to arsenic exposure in the U.S.

These are important issues in projecting

risk from the observed data range in the

epidemiologic studies to lower

environmental exposures experienced

from U.S. drinking water.

Until further research is completed,

questions will remain regarding the

dose-response relationship at low

environmental levels. The several

Taiwan studies have strengths in their

long-term observation of exposed

persons and coverage of very large

populations (>40,000 persons).

Additionally, the collection of

pathology data was unusually thorough.

Moreover, the populations were quite

homogeneous in terms of lifestyle.

Limitations in exposure information

exist that are not unusual in such

studies. In ecological epidemiology

studies of this kind, the exposure of

individuals is difficult to measure

because their exposure from water and

food is not known. This results in

uncertainties in defining a doseresponse relationship. The studies in

Chile and Argentina are more limited in

extent, (e.g., years of coverage, number

of persons, or number of arsenic

exposure categories analyzed), but

provide important findings which

corroborate one another and those of the

Taiwan studies.

These epidemiological studies

provide the basis for assessing potential

risk from lower concentrations of

inorganic arsenic in drinking water,

without having to adjust for crossspecies toxicity interpretation.

Ordinarily, the characteristics of human

carcinogens can be explored and

experimentally defined in test animals.

Dose-response can be measured, and

animal studies may identify internal

transport, metabolism, elimination, and

subcellular events that explain the

carcinogenic process. Arsenic presents

unique problems for quantitative risk

assessment because there is no test

animal species in which to study its

carcinogenicity. While such studies

have been undertaken, it appears that

test animals, unlike humans, do not

respond to inorganic arsenic exposure

by developing cancer. Their metabolism

of inorganic arsenic is also

quantitatively different than humans.

Inorganic arsenic does not react directly

with DNA. If it did, it would be

expected to cause similar effects across

species and to cause response in a

proportionate relationship to dose.

Moreover, its metabolism, internal

disposition, and excretion are different

and vary across animal and plant

species and humans—in test studies and

in nature.

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38903

Until more is known, EPA will take a

traditional, public health conservative

approach to considering the potential

risks of drinking water containing

inorganic arsenic. EPA recognizes that

the traditional approach may

overestimate risk, as explained in the

next section.

B. What Is the MCLG?

EPA concludes that exposure to

inorganic arsenic induces cancer in

humans. It also is associated with

adverse noncancer effects such as

hypertension (NRC, 1999). The NRC

report stated that ‘‘Data on the modes of

action for carcinogenicity can help to

predict the shape of cancer doseresponse curves below the level of

direct observation of tumors. * * * For

arsenic carcinogenicity * * * modes of

action that are considered most

plausible (namely, indirect mechanisms

of mutagenicity) lead to a sublinear

dose-response at some point below the

level at which a significant increase in

tumors is observed. However, because a

specific mode (or modes) of action has

not been identified at this time, it is

prudent not to rule out the possibility of

a linear response (NRC 1999, pgs. 213–

214).’’ The expert panel report (US EPA,

1997d, pg. 31) stated: ‘‘* * * for each of

the modes of action regarded as

plausible, the dose-response would

either show a threshold or would be

nonlinear. * * * [H]owever, ‘‘the dose

response for arsenic at low doses would

likely be truly nonlinear—i.e., with a

decreasing slope as the dose decreased.

However, at very low doses such a curve

might effectively be linear but with a

very shallow slope, probably

indistinguishable from a threshold.’’ In

the absence of a known mode of

action(s), EPA has no basis for

determining the shape of a sublinear

dose-response curve for inorganic

arsenic. As a result, consistent with EPA

public health policy, EPA will continue

to use a linear dose-response curve for

inorganic arsenic effects. Using a linear

type of a dose-response curve, EPA is

proposing an MCLG of zero. The Agency

welcomes comments on setting a

nonzero MCLG and submission of data

supporting a nonzero MCLG.

C. How Will a Health Advisory Protect

Potentially Sensitive Subpopulations?

The NRC report was inconclusive

about the health risks to pregnant

woman, developing fetus, infants,

lactating women, and children. When

the Agency completes this rulemaking,

it intends to issue a health advisory on

arsenic in drinking water, in order to

decrease risk to sensitive

subpopulations prior to the

implementation of the new MCL. The

effective date of a revised MCL will be

three to five years after the final rule is

issued (2004–2006).

A health advisory is a non-regulatory

document that supports water providers

in their independent decisions on

actions to take regarding water

contaminants and their communication

with the general public. In the health

advisory on arsenic the Agency intends

to address a precautionary step to

protect infants. This step would be to

avoid using water containing high levels

of arsenic to make up infant formula.

The reason for this precaution is that

epidemiologic studies indicate that

arsenic in drinking water (Lewis et al.,

1999) affects the cardiovascular system.

While there are no studies of effects of

arsenic on human infants, both the

cardiovascular system and brain (and its

vascular system) continue to develop

after birth (Thompson, P.M et al. 2000);

thus, the effects discussed in this notice

on the cardiovascular system raise a

concern about potential effects of

arsenic on infant development. In large

part, causes of cerebrovascular incidents

(stroke) in children are not understood

except for certain, known associations

with organic diseases and genetic

diseases. Congenital and acquired heart

disease are the most common cause of

stroke in children. The current toxicity

data on arsenic do not contradict this

precautionary view.

D. How Will the Clean Water Act

Criterion Be Affected by This

Regulation?

EPA is also working to harmonize the

human health arsenic criteria for the

Clean Water Act (CWA) and the SDWA.

The major reason for the present

difference (discussed in section II.D.)

between the MCL and the Ambient

Water Quality Criterion (AWQC) was

the result of using separate bases for

determining the two standards. The

AWQC for arsenic was derived from the

risk assessment for arsenic-induced skin

cancer, while the current SDWA MCL,

adopted in 1975 as a National Interim

Primary Drinking Water Regulation,

evolved from the U.S. Public Health

Service standard dating back to the

1940s. The Agency will use the

conclusions of the NRC (1999) report to

form the human health basis for both

the AWQC and the MCL. However, the

CWA and SDWA statutes require that

the Agency consider different factors

during the derivation of a standard. For

example, SDWA requires that the

Agency consider: (1) Cost/benefit

analyses, including sizes of the public

water systems, (2) the level of arsenic

that can be analyzed by laboratories on

a routine basis, [i.e., the practical

quantitation limit (PQL)] and (3)

treatment techniques for removing the

chemical from the water. On the other

hand, the CWA requires the EPA to

consider water and fish consumption

(including amount of fish eaten, percent

lipid in the fish and the

bioaccumulation factor for the chemical

in the fish), but not cost/benefits,

analytical or treatment techniques.

Accordingly, developing a AWQC under

the CWA may produce a standard that

differs from the MCL derived under the

SDWA even though both standards are

based on the same health endpoint. The

Agency will begin work on a new

AWQC for arsenic after promulgating

the MCL for arsenic.

V. EPA’s Estimates of Arsenic

Occurrence

One of the key components in the

development of the proposed arsenic

rule is the analysis of arsenic occurrence

in public water supplies, both

community water systems (CWS) and

non-transient, non-community, water

systems (NTNCWS). EPA’s national

occurrence assessment of arsenic

provides a basis for estimating:

(1) The number of systems expected

to exceed various arsenic levels;

(2) the number of people exposed to

the different levels of arsenic; and

(3) the variability in arsenic levels in

water systems among the wells and/or

entry points to the distribution system.

EPA uses the estimate of the total

number of systems and populations

affected in the United States in its costbenefit analysis. EPA is seeking

comment on its analysis of arsenic

occurrence in the U.S., as well as

requesting additional data.

A. What Data Did EPA Evaluate?

For previous occurrence analyses EPA

used four older national arsenic

databases: (1) The National Inorganic

and Radionuclide Survey (NIRS),

conducted from 1984 to 1986, for

ground water CWSs; (2) a 1976–1977

National Organic Monitoring Survey

(NOMS); (3) a 1978–1980 Rural Water

Survey (RWS); and (4) the 1978

Community Water System Survey

(CWSS) for surface water CWSs.

However, these older databases have

several limitations. First, the surveys of

surface water systems will not reflect

changes in raw water sources which

occurred in the last twenty years.

Second, filtration treatment added to

comply with the Surface Water

Treatment Rule (110 54 FR 27486, June

29, 1989) would tend to decrease

arsenic exposure, through incidental

arsenic removal. Finally, most of the

38904 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

data were censored (reported as less

than the analytical test method

detection level or reporting limit, e.g.,

‘‘not detected’’ or ‘‘<5 μg/L’’). NIRS,

CWSS, and RWS, respectively, had

93%, 97%, and 90% censored data. This

limits the estimation of low level

occurrence of arsenic and makes it

statistically difficult to extrapolate

occurrence with the limited amount of

non-censored data. The EPA Science

Advisory Board recommended that EPA

abandon the older data when sufficient

new data become available because of

the high percentage of censored data in

the older surveys and the difficulty of

using highly censored data sets to

estimate occurrence (US EPA, 1995).

Therefore, with improved analytical

techniques for detecting arsenic at lower

levels, as low as 0.5 μg/L, and the lower

reporting limits in the new data

received by EPA, the Agency focused

the data evaluation on post-1980 data

sources for estimating national

occurrence.

Since 1992, EPA OGWDW has

received arsenic databases from other

EPA offices, States, public water

utilities, and associations. EPA

combined the compliance monitoring

data obtained from States into the ‘‘25

States’’ database. The Agency evaluated

the databases listed in Table V–1. (Note

that EPA’s database, the Safe Drinking

Water Information System (SDWIS),

only records violations of the current

arsenic MCL, so it is censored at 50 μg/

L.) A more detailed description of the

databases and evaluations are presented

in the EPA document titled ‘‘Arsenic

Occurrence in Public Drinking Water

Supplies,’’ (US EPA, 2000b).

TABLE V–1.—SUMMARY OF ARSENIC DATA SOURCES

Data source Reporting level

(μg/L) Number of CWSs Source water Water type

25 States1 .............. <1 to 10 ................ >19,000 ................ Surface, Ground .................................. finished.

Metro 2 .................... 1 ............................ 140 ........................ Surface, Ground .................................. raw & finished.

NAOS3 ................... 0.5 ......................... <517 ..................... Surface, Ground .................................. raw & predicted finished.

USGS4 ................... 1 ............................ not available

(20,000 sites).

Ground ................................................. raw.

ACWA5 .................. 0.1 to 1 ................. 180 (1,500 samples).Surface, Ground .................................. finished.

WESTCAS6 ........... not available ......... not available ......... Ground ................................................. finished.

1Arsenic compliance monitoring data from community water systems (CWSs) from Alabama, Alaska, Arizona, Arkansas, California, Illinois, Indiana, Kentucky, Kansas, Maine, Michigan, Minnesota, Missouri, Montana, Nevada, New Hampshire, New Jersey, New Mexico, North Carolina,

North Dakota, Ohio, Oklahoma, Oregon, Texas, and Utah. 2 Metropolitan Water District of Southern California (MWDSC, or Metro) 1992–1993 national survey of 140 CWSs serving more than 10,000

people. 3 1996 National Arsenic Occurrence Survey (NAOS) funded by the Water Industry Technical Action Fund (WITAF), which includes the following

organizations: American Water Works Association, National Association of Water Companies, Association of Metropolitan Water Agencies, National Rural Water Association, and National Water Resources Association. 4 U.S. Geological Survey (USGS) ambient (raw water) ground water from approximately 20,000 wells throughout the U.S. used for various purposes, including public supply, research, agriculture, industry and domestic supply. 5 1993 survey from 180 water agencies, utilities, and cities in southern California, conducted by the Association of California Water Agencies

(ACWA). 6 1997 Western Coalition of Arid States (WESTCAS) Research Committee Arsenic Occurrence Study which aggregated arsenic data (e.g., median arsenic value for county, city, or provider) from Arizona, New Mexico, and Nevada.

B. What Databases Did EPA Use?

EPA evaluated the databases for

representativeness, accuracy and

coverage of community water systems in

the U.S. EPA determined that the

compliance monitoring data from the 25

States (‘‘25-States database’’) would

establish the most accurate and

scientifically defensible national

occurrence and exposure distributions

of arsenic in public ground water and

surface water supplies. Figure V.1

shows the coverage of these States in the

U.S. The 25-States database provides

more finished water arsenic data, from

over 19,000 ground and surface water

CWSs, than the other national

databases. EPA is interested in finished

water data, rather than raw water data,

because it indicates the current arsenic

levels in water systems after treatment

and reflects their customers’ level of

exposure to arsenic. The 25-States

database provides system and

individual arsenic data for a significant

number of CWSs in each State. The

arsenic data can be linked directly to

specific water systems by their

identification code to obtain additional

information in SDWIS, such as

population served, system type (e.g.,

CWS, NTNCWS), source type (e.g.,

ground water, surface water, purchased

water, ground water under the

influence), and location. For this reason,

EPA chose to use the compliance

monitoring data from the States of

California, Nevada, New Mexico, and

Arizona, rather than the data about

these States from ACWA and

WESTCAS.

Most of the 25-States data had

reporting limits of less than 2 μg/L. In

addition, the database includes multiple

samples from the water systems over

time and from multiple sources within

the systems. The multiple samples

provide for a more accurate estimate of

the arsenic levels in the systems, than

a survey with one sample per system.

The arsenic compliance monitoring data

provides point-of-entry or well data

within systems from eight States, which

is used for intrasystem variability

analysis (discussed in Section V.G).

Intrasystem variability analysis provides

an understanding of the variation of

arsenic levels within a system, from

well to well or entry point to entry

point.

EPA also received arsenic data from

Florida, Idaho, Iowa, Louisiana,

Pennsylvania, and South Dakota;

however EPA did not include these

States in the database. These States

either provided data that (1) could not

be linked to CWSs; (2) did not indicate

if the results were censored or noncensored; (3) were all zero, without

providing the analytical/reporting limit;

or (4) rounded results to the nearest ten

μg/L.

EPA used the USGS and NAOS

databases and their occurrence

estimates for comparison purposes. In

addition, EPA used the NAOS approach

to partitioning of the U.S. for its

analysis.

We combined State data sets with

different data naming conventions, and

the database development and data

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38905

conditioning process is described in

Appendix D–3 of the occurrence

support document (US EPA, 2000b).

Appendix D–1 identifies who provided

the data and data provided for each

State in the 25-State database. Appendix

D–2 lists the data names we used to

develop the national database. We

assumed that the data represented

compliance sampling, and some States

have reportedly provided source water

data and compliance data. If you are

aware of errors in our data set, please let

us know. Also, additional data would

reduce the uncertainty of our national

occurrence estimate. We encourage

commenters to submit arsenic

compliance monitoring data sets either

from States not already in our data set,

more recent data that were not included

in the described data sets, or a more

official version of compliance data. We

will use this information to obtain a

more representative national occurrence

estimate for the final rule.

BILLING CODE 6560–50–P

38906 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

BILLING CODE 6560–50–C

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38907

C. How Did EPA Estimate National

Occurrence of Arsenic in Drinking

Water?

EPA derived the national estimates of

arsenic occurrence in three steps: (1)

Estimate system means; (2) estimate

State distribution of system means; and

(3) estimate national distributions of

system means.

As discussed in section V.B, EPA

determined that the 25-States database

would be used for estimating national

occurrence. EPA calculated a system

average for each water system in its

database. When the database provided 5

or more detected (greater than the

reporting limit) arsenic samples in a

system, we used the method of

‘‘regression on order statistics’’ (Helsel

and Cohn, 1988) to extrapolate values

for the non-detected observations, then

calculated the arithmetic mean. When

there were 1 to 4 detected values, we

substituted half the reporting limit for

each non-detected value (less than the

reporting limit) and calculated an

arithmetic average. When there were no

detected values (all samples had nondetected values), we set the arsenic

system average as a non-detect at the

mode (most frequently occurring) of the

reporting limits. As a result, each

system has a calculated system mean,

either a non-detected or detected value.

In order to estimate the distribution of

systems means in a State, EPA

aggregated the system means into a

single distribution and derived separate

estimates of percentage of systems with

average arsenic values greater than 2, 3,

5, 10, 15, 20, 25, 30, 40, and 50 μg/L

(referred to as exceedance estimates).

We developed separate estimates for

ground water and surface water systems.

Within each State, EPA fit a lognormal

distribution to the population of

estimated system means, and used the

fitted distribution to estimate

exceedance probabilities. However,

when fitting the lognormal distribution,

EPA excluded system means which

were estimated to be less than their

reporting limit, since these require more

extrapolation below the reporting limit

and were judged to be less reliable. EPA

also did not make exceedance estimates

below the most frequently occurring

reporting limit or censoring point in

each of the States.

To estimate the national distribution

of system means, EPA grouped the

States into the seven regions developed

in the NAOS (Frey and Edwards, 1997).

Frey and Edwards derived a natural

occurrence factor by weighting

detection, number of data points, and

higher arsenic values from data in the

USGS WATSTORE water quality

database and the Metro survey. Then

they grouped States into seven regions

based on the calculated natural

occurrence factors. Figure V.1 is a map

of the U.S. with the NAOS regions. With

this regional grouping of States, EPA

developed separate regional estimates

for surface water and ground water

systems. In a separate analysis, EPA

found the national result from using the

NAOS regions to be similar to grouping

States into different regions, based on a

preliminary examination of generally

related exceedance probabilities.

EPA derived each regional estimate by

using exceedance estimates from the

States with compliance monitoring data

in the region, weighted by the number

of community water systems in those

specific States. For example, we used

the exceedance estimates from Montana

and North Dakota, weighted by the

number of community water systems in

those States, to derive the North Central

region estimate. Within each region, we

estimated the percentages of systems

with average arsenic values greater than

2, 3, 5, 10, 15, 20, 25, 30, 40, and 50 μg/

L. We then weighted the regional

exceedance estimates, by the total

number of community water systems in

each region (including the number of

community water systems in the States

without compliance monitoring data) to

obtain national estimates of percentages

of systems with average arsenic values

greater than 2, 3, 5, 10, 15, 20, 25, 30,

40, and 50 μg/L.

EPA believes that separate estimates

are not justified for different system

sizes. A graphical analysis (‘‘box and

whisker’’ plots) of the occurrence

distributions suggests that in some

regions, systems in different size

categories do have different mean

concentrations. However the differences

in means are much smaller than the

variability of the observed

concentrations. Moreover, the

differences do not vary with system size

in a consistent way. For example, for

ground water systems, arsenic

concentrations in the New England

Region (NAOS Region 1) decrease as

system size increases, while in the MidAtlantic and South Central regions

(NAOS Regions 2 and 5), arsenic

concentrations increase as system size

increases. In the four remaining regions,

no systematic patterns are evident. For

these reasons, and because additional

stratification decreases the precision of

the estimates, EPA has not developed

separate estimates for different system

sizes.

The method of substitution that EPA

used for non-detected concentrations

(described above) is different from the

method that water systems use for

determining compliance with the MCL:

We substituted positive values for nondetects, while for purposes of

compliance, non-detected

concentrations are treated as zero.

Therefore, our estimates of occurrence

will be higher on average than those

found by water systems monitoring for

compliance with the MCL. As a result

we might overestimate both the costs

and benefits of the proposed MCL.

However we believe that our estimate of

occurrence is justified, for two reasons.

First, it is more accurate (less biased).

Second, as the detection limits of

analytical methods continue to improve

(i.e., lower than 1 μg/L), the difference

between the two substitution methods

will be small and will occur in the range

below the MCL.

D. What Are the National Occurrence

Estimates of Arsenic in Drinking Water

for Community Water Systems?

Arsenic is found in both ground water

and surface water sources. Figure V.1

presents the regions of the United States

referred to in this discussion. Table V–

2 data indicate that higher levels of

arsenic tend to be found in ground

water sources (e.g., aquifers) than in

surface water sources (e.g., lakes, rivers).

The 25-States finished water data also

indicate that the North Central, Midwest

Central, and New England regions of the

United States tend to have low to

moderate (2–10 μg/L) ground water

arsenic levels, while the Western region

tends to have higher levels of ground

water arsenic (>10 μg/L) than the other

regions. Systems in the other regions of

the U.S. may have high levels of arsenic

(hot spots), while many systems and

portions of the States in the listed

regions may not have any detected

arsenic in their drinking water.

38908 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

TABLE V–2.—REGIONAL EXCEEDANCE PROBABILITY DISTRIBUTION ESTIMATES

Region

Percent of systems exceeding arsenic concentrations (μg/L) of:

2 3 5 10 15 20 25 30 40 50

Ground Water Systems

New England .................................................... 29 21 21 7 4 3 2 2 1 0.7

Mid Atlantic ....................................................... ............ ............ *0.3 *1 0.3 0.1 0.06 0.03 0.009 0.003

South East ........................................................ 2 1 0.5 0.2 0.1 0.07 0.05 0.04 0.02 .01

Midwest ............................................................ 28 21 14 6 4 2 2 1 .8 0.5

South Central ................................................... 27 19 10 4 2 1 0.8 0.5 0.3 0.2

North Central .................................................... 29 21 13 6 4 2 2 1 0.9 0.6

West ................................................................. 42 31 25 12 7 5 4 3 2 1

Surface Water Systems

New England .................................................... 11 *8 *9 1.0 0.6 0.4 0.3 0.3 0.2 0.1

Mid Atlantic ....................................................... ............ ............ *0.1 *0.1 0.01 0.001 0 0 0 0

South East ........................................................ 0.8 0.2 0.03 0.001 0 0 0 0 0 0

Midwest ............................................................ 4 3 1 0.4 0.2 0.1 0.1 0.07 0.05 0.03

South Central ................................................... 9 4 1 0.3 0.1 0.08 0.05 0.03 0.02 0.01

North Central .................................................... 20 10 4 0.8 0.2 0.1 0.05 0.02 0.008 0.003

West ................................................................. 19 13 7 3 2 1 0.8 0.6 0.4 0.3

*Estimates at these regions and levels are inconsistent, in that the estimated % exceedances at lower values are smaller than the estimates at

higher values. This inconsistency occurs because fewer States were used to estimate % exceedances at lower levels. EPA did not attempt to resolve the inconsistency, but combined the regional distribution into a national distribution which is consistent.

The estimates of the number of CWSs

expected to exceed different arsenic

levels is based on the distribution of

average arsenic concentrations in water

systems. Using the data from the 25-

States database, EPA estimates that

5.4% of ground water CWSs and 0.7%

of surface CWSs have average arsenic

levels above 10 μg/L. Similarly, 12.1%

and 2.9% of ground water CWSs and

surface water CWSs, respectively, have

average arsenic levels above 5 μg/L.

Tables V–3 and V–4 provide estimates

by system size category. The percentage

of systems that have average arsenic

levels within a specific range does not

vary across the system size categories.

For example, 2.3% of ground water

systems in each of the five system size

categories have average arsenic levels in

the range of >10 μg/L to 15 μg/L.

Therefore, the arsenic exceedance

estimates have the same distribution in

any system size. These estimates of

percent (or probability) of systems that

have average arsenic levels within a

specific range are multiplied by the

number of systems in each size category

to derive the number of systems in

Table V–3 and V–4.

TABLE V–3.—STATISTICAL ESTIMATES OF NUMBER OF GROUND WATER CWSS WITH AVERAGE ARSENIC

CONCENTRATIONS IN SPECIFIED RANGES

System size (population served)

Number of systems with average arsenic concentrations in specified ranges (μg/L; 43,749 systems total)

<2.0 >2.0 to

3.0

>3.0 to

5.0

>5.0 to

10.0

>10.0 to

15.0

>15.0 to

20.0

>20.0 to

30.0

>30.0 to

50.0 >50.0

25 to 500 ...................................... 21,325 2,158 2,268 1,960 674 314 287 188 129

501 to 3,300 ................................. 7,616 771 810 700 241 112 103 67 46

3,301 to 10,000 ............................ 1,811 183 193 167 57 27 24 16 11

10,001 to 50,000 .......................... 933 94 99 86 29 14 13 8 6

>50,000 ........................................ 154 16 16 14 5 2 2 1 1

Total ...................................... 31,840 3,221 3,386 2,927 1,006 468 429 280 192

(% of systems) ...................... (72.8%) (7.4%) (7.7%) (6.7%) (2.3%) (1.1%) (1.0%) (0.6%) (0.4%)

Note: Totals may not add up due to rounding of the number of systems to the nearest whole number. Systems serving fewer than 25 people

are not included in this table. The estimates in this table do not take into account most treatment in place; in particular most of the systems in

the ‘‘>50.0’’ column will have treated for arsenic in order to reduce their concentration below 50 μg/L. See text for more details.

In Tables V–3 and V–4, the estimated

numbers of systems with mean

concentrations above 50 μg/L do not

represent the number of systems which

are believed to be out of compliance

with the current MCL of 50 μg/L; nor do

they represent actual systems at all.

Rather, they are statistical

extrapolations above 50 μg/L, based

primarily on data below 50 μg/L. Since

most data below 50 μg/L comes from

systems which have not treated for

arsenic, the ‘‘>50.0’’ columns in Tables

V–3 and V–4 do not take into account

most treatment currently in place.

Therefore, the ‘‘>50.0’’ columns

represent the estimated number of

systems which would have mean

arsenic concentrations above 50 μg/L if

they had not treated for arsenic. By

comparison with Tables V–3 and V–4,

during the three-year period from

September 1994 through August 1997,

EPA recorded a total of 14 samples from

10 public water systems in which

arsenic concentrations exceeded 50 μg/

L.

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38909

TABLE V–4.—STATISTICAL ESTIMATES OF NUMBER OF SURFACE WATER CWSS WITH AVERAGE ARSENIC

CONCENTRATIONS IN SPECIFIED RANGES

System size (population served)

Number of systems with average arsenic concentrations in specified ranges (μg/L; 10,683 systems total)

<2.0 >2.0 to

3.0

>3.0 to

5.0

>5.0 to

10.0

>10.0 to

15.0

>15.0 to

20.0

>20.0 to

30.0

>30.0 to

50.0 >50.0

25 to 500 ...................................... 2,794 122 94 69 11 4 4 2 2

501 to 3,300 ................................. 3,308 144 111 82 13 5 4 3 2

3,301 to 10,000 ............................ 1,656 72 56 41 6 3 2 1 1

10,001 to 50,000 .......................... 1,384 60 47 34 5 2 2 1 1

> 50,000 ....................................... 477 21 16 12 2 1 1 0 0

Total ...................................... 9,622 419 323 239 37 15 13 8 7

(% of systems) ...................... (90.1%) (3.9%) (3.0%) (2.2%) (0.4%) (0.1%) (0.1%) (0.1%) (0.1%)

Note: Totals may not add up due to rounding of the number of systems to the nearest whole number. Systems serving fewer than 25 people

are not included in this table. The estimates in this table do not take into account most treatment in place; in particular most of the systems in

the ‘‘>50.0’’ column will have treated for arsenic in order to reduce their concentration below 50 μg/L. See text for more details.

E. How Do EPA’s Estimates Compare

With Other Recent National Occurrence

Estimates?

In addition to EPA’s national

occurrence results presented in section

V.D., two additional studies recently

developed national occurrence

estimates for arsenic in drinking water:

the NAOS study (Frey and Edwards,

1997), and the USGS study of arsenic

occurrence in ground water (USGS,

2000). The databases that supported the

NAOS and USGS estimates are briefly

described in section V.A., ‘‘What data

did EPA evaluate?’’ Each of these

occurrence estimates was developed in

a slightly different manner. Whereas

EPA’s occurrence estimates are based on

compliance monitoring data from more

than 19,000 CWSs in 25 states, the

NAOS occurrence estimates are based

on a stratified random sampling from

representative groups defined by source

type, system size, and geographic

location. The NAOS database contains

435 predicted finished water arsenic

data points (derived from raw water

arsenic concentrations and treatment

information), from more than 400 CWSs.

The USGS analysis is based on arsenic

ambient (untreated, or raw water)

ground water data, providing 17,496

samples for 1,528 counties (with 5 or

more data points) in the United States

(out of a total of 3,222 counties). USGS

derived exceedance estimates for each

county by calculating the percentage of

data points in each county exceeding

specific concentrations, from 1 μg/L to

50 μg/L. Then USGS associated the

percentages for each county with the

number of CWSs that use ground water

in these counties, which was based on

data derived from SDWIS. This

information was aggregated for all of the

appropriate counties to derive the

national estimates for ground water

CWSs. USGS did not have estimates for

surface water CWSs.

TABLE V–5.—COMPARISON OF CWSS FROM EPA, NAOS, AND USGS ESTIMATES EXCEEDING ARSENIC

CONCENTRATIONS

% CWS exceeding

EPA GW

&SW

(percent)

NAOS

GW &

SW (percent)

EPA GW

(percent)

USGS

GW (percent)

2 μg/L ............................................................................................................................................... 24.1 21.7 27.2 25.0

5 μg/L ............................................................................................................................................... 10.3 11.5 12.1 13.6

10 μ/L ............................................................................................................................................... 4.5 4.5 5.4 7.6

Table V–5 compares the EPA, NAOS,

and USGS estimates of the percent of

samples exceeding various arsenic

concentrations. At a concentration of 2

μg/L, the EPA national exceedance

estimate for both surface water and

ground water CWSs (24.1 percent) is

higher than the NAOS estimate (21.7

percent). At 5 μg/L, the EPA and NAOS

predicted exceedance probabilities are

relatively similar (10.3 and 11.5 percent,

respectively). These two estimates are

the same at 10 μg/L (4.5 percent). For

ground water CWSs, the USGS and EPA

estimates are also relatively similar. At

2 μg/L, the EPA national ground water

exceedance estimate (27.2 percent) is

slightly higher than the USGS estimate

(25.0 percent). At 5 and 10 μg/L, the

USGS exceedance estimates (13.6

percent and 7.6 percent, respectively)

are slightly higher than the EPA

estimates (12.1 percent and 5.4 percent).

This comparison of exceedance

probabilities suggests that EPA’s arsenic

occurrence projections based on

compliance monitoring data are

relatively close to the NAOS and USGS

projections through the range of this

comparison. In addition, the USGS

estimates are expected to be slightly

higher than the EPA estimates for

ground water, because they are based on

raw water arsenic levels (untreated).

F. What Are the National Occurrence

Estimates of Arsenic in Drinking Water

for Non-Transient, Non-Community

Water Systems?

The 25-States database contains data

for non-transient, non-community water

systems (NTNCWSs) in 15 States (two

additional States only provided data

from two systems). NTNCWSs are

public water systems that regularly

serve at least 25 of the same persons

more than 6 months a year. Most

NTNCWSs serve less than 3,300 people

(99.5%) and use ground water (96%).

EPA calculated basic statistics for

ground water CWSs and NTNCWSs in

each of these States. EPA compared the

data and found that arsenic

distributions in NTNCWSs are quite

38910 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

similar to arsenic distributions in CWSs.

In general, the means, standard

deviations, and level of censoring for

CWSs in a particular State are very close

to the levels observed in NTNCWSs in

that State. In some States, mean levels

are slightly higher in CWSs than in

NTNCWSs, whereas in others, mean

levels are slightly lower in CWSs. There

is no clear pattern and the differences

are relatively minor, suggesting that any

differences are due to random variation,

rather than systematic underlying

differences between NTNCWSs and

CWSs. As a result, the occurrence

distributions for CWSs were used to

derive the occurrence distributions for

NTNCWS systems. If the NTNCWSs

data from the 15 States were used to

derive the estimates, there would have

been less spatial coverage of United

States, which would have resulted in

more uncertainty in the estimate. The

NTNCWSs estimates are presented in

Tables V–6 and V–7.

As in the case of Tables V–3 and V–

4, the estimated numbers of systems in

Tables V–6 and V–7 with mean

concentrations above 50 μg/L do not

represent the number of systems which

are believed to be out of compliance

with the current MCL of 50 μg/L; nor do

they represent actual systems at all.

Rather they represent the estimated

number of systems which would have

mean arsenic concentrations above 50

μg/L if they had not treated for arsenic.

By comparison with Tables V–6 and V–

7, during the three-year period from

September 1994 through August 1997,

EPA recorded a total of 14 samples from

10 public water systems in which

arsenic concentrations exceeded 50 μg/

L.

TABLE V–6.—STATISTICAL ESTIMATES OF NUMBER OF GROUND WATER NTNCWSS WITH AVERAGE ARSENIC

CONCENTRATIONS IN SPECIFIED RANGES

System size (population served)

Number of systems with average arsenic concentrations in specified ranges (μg/L; 19,293 systems total)

<2.0 >2.0 to

3.0

>3.0 to

5.0

>5.0 to

10.0

>10.0 to

15.0

>15.0 to

20.0

>20.0 to

30.0

>30.0 to

50.0 >50.0

25 to 500 ...................................... 12,088 1,223 1,285 1,111 382 178 163 106 73

501 to 3,300 ................................. 1,902 192 202 175 60 28 26 17 11

3,301 to 10,000 ............................ 43 4 5 4 1 1 1 0 0

10,001 to 50,000 .......................... 8 1 1 1 0 0 0 0 0

> 50,000 ....................................... 0 0 0 0 0 0 0 0 0

Total ...................................... 14,041 1,421 1,493 1,291 444 206 189 123 85

(% of systems) ...................... (72.8%) (7.4%) (7.7%) (6.7%( (2.3%) (1.1%) (1.0%) (0.6%) (0.4%)

Note: Totals may not add up due to rounding of the number of systems to the nearest whole number. Systems serving fewer than 25 people

are not included in this table. The estimates in this table do not take into account most treatment in place; in particular most of the systems in

the ‘‘>50.0’’ column will have treated for arsenic in order to reduce their concentration below 50 μg/L. See text for more details.

TABLE V–7.—STATISTICAL ESTIMATES OF NUMBER OF SURFACE WATER NTNCWSS WITH AVERAGE ARSENIC

CONCENTRATIONS IN SPECIFIED RANGES

System size (population served)

Number of systems with average arsenic concentrations in specified ranges (‘‘μg/L; 764 systems total)

<2.0 >2.0 to

3.0

>3.0 to

5.0

>5.0 to

10.0

>10.0 to

15.0

>15.0 to

20.0

>20.0 to

30.0

>30.0 to

50.0 >50.0

25 to 500 ...................................... 502 22 17 12 2 1 1 0 0

501 to 3,300 ................................. 163 7 5 4 1 0 0 0 0

3,301 to 10,000 ............................ 18 1 1 0 0 0 0 0 0

10,001 to 50,000 .......................... 4 0 0 0 0 0 0 0 0

50,000 .......................................... 2 0 0 0 0 0 0 0 0

Total ......................................

(% of systems) ...................... 688

(90.1%)

30

(3.9%)

23

(3.0%)

17

(2.2%)

3

(0.4%)

1

(0.1%)

1

(0.1%)

1

(0.1%)

0

(0.1%)

Note: Totals may not add up due to rounding of the number of systems to the nearest whole number. Systems serving fewer than 25 people

are not included in this table. The estimates in this table do not take into account most treatment in place; in particular most of the systems in

the ‘‘>50.0’’ column will have treated for arsenic in order to reduce their concentration below 50 μg/L. See text for more details.

G. How Do Arsenic Levels Vary From

Source To Source and Over Time?

EPA analyzed the variability of

arsenic concentrations within a system,

from well to well or entry point to entry

point (sampling point). This analysis

allows EPA to estimate the number of

sampling points in a system that may be

above the proposed MCL and to

improve estimation of the treatment

costs for systems with multiple

sampling points. The result of the

intrasystem analysis is a constant

coefficient of variation (CV), which is

one of the inputs to the cost-benefit

computer modeling. EPA analyzed six

of the eight States that provided

intrasystem data: California, Utah, New

Mexico, Oklahoma, Illinois and Indiana.

Arkansas and Alabama were not

analyzed because these States had very

little occurrence of arsenic and almost

all of the arsenic values were below the

detection limit. After statistical analysis

of 127 systems with five or more

sampling points, EPA derived an

arithmetic average CV of 0.64 or 64%.

The EPA document titled ‘‘Arsenic

Occurrence in Public Drinking Water

Supplies,’’ presents this statistical

analysis (US EPA, 2000b).

USGS examined its raw water arsenic

data to assess the variability of arsenic

levels over time and to determine

whether there are temporal trends

(USGS, 2000). Data came from about 350

wells with 10 or more arsenic analyses

collected over different time periods.

These wells were used for various

purposes, such as public supply,

research, agriculture, industry, and

domestic supply, and encompassed

non-potable and potable water quality.

USGS conducted a regression analysis

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38911

of arsenic concentration and time for

each well and found that most of the

wells had little or no change in

concentration over time (low ‘‘rsquared’’ values when arsenic

concentrations were regressed with

time). Arsenic levels for most of the

wells probably do not consistently

increase or decrease over time. In

addition, USGS found that well depth

had no relationship to temporal

variability. To determine the extent of

the temporal variability, EPA analyzed

the CVs for the mean arsenic level in the

wells. More than 100 wells had a CV

and standard deviation of zero. Most of

these wells consistently had arsenic

concentrations below the detection limit

of 1 μg/L. EPA examined the CVs for the

other wells in relation to the mean

arsenic level and found a relatively

constant CV on the lognormal scale. The

geometric mean of the CVs, excluding

CVs of zero, is 0.39 or 39%. The report

(USGS, 2000) listed several factors that

may contribute to this variability,

including natural variability in

geochemistry or source of

contamination, sampling technique, and

changes in pumping over time.

H. How Did EPA Evaluate CoOccurrence?

Sections 1412(b)(3)(C)(i)(II), (III) and

(VI) of the SDWA, as amended in 1996,

require EPA to take into account

activities under preceding rules which

may have impacts on each new

successive rule. To fulfill this need EPA

began the analysis of the co-occurrence

of drinking water contaminants. The

information on co-occurrence will be

used to determine the level of overlap

in regulatory requirements. For

example, this will include cases where

treatment technologies applied for one

regulation may resolve monitoring and/

or additional treatment needs for

another regulation or where water

utilities may incur costs for installing

multiple treatments to address other cooccurring substances. This information

may also be used to show where specific

levels of one contaminant may interfere

with the treatment technology for

another.

1. Data

For the co-occurrence analysis, EPA

relied on data from the National Water

Information System (NWIS), a U.S.

Geological Survey (USGS) database. The

NWIS database was used for several

reasons:

• It contains both ground and surface

water data;

• It is national in scope, representing

raw water samples from approximately

40,000 observation stations across the

U.S.; and

• It provides latitude/longitude

coordinates for monitoring stations,

which can be used in subsequent

analyses to associate with Public Water

Supply Systems.

NWIS contains a water quality data

storage retrieval system developed by

the USGS Water Resources Division.

NWIS is a distributed water database;

data can be processed over a network of

computers at USGS offices throughout

the U.S. The system comprises the

Automated Data Processing System, the

Ground Water Site Inventory System,

the Water-Quality System, and the

Water-Use Data System. NWIS does not

represent Public Water Supply Systems

directly but can be associated with them

because it provides latitude/longitude

coordinates for monitoring stations.

Using the NWIS data, arsenic was

analyzed with 18 other constituents.

The other constituents included:

Sulfate, radon, radium, uranium, nitrate,

antimony, barium, beryllium, cadmium,

chromium, cyanide, iron, manganese,

mercury, nickel, nitrite, selenium,

thallium, hardness, and total dissolved

solids. An additional set of ancillary

parameters were selected for use as

indicators of the hydrogeologic and

geochemical conditions that could

influence the co-occurrence of specific

constituents. These ancillary parameters

included: turbidity, conductance,

dissolved oxygen, pH, alkalinity, well

depth, and depth below land.

2. Results of the Co-occurrence Analysis

(US EPA, 1999f)

Dissolved arsenic was observed to

have 5442 detected counts and total

arsenic was observed to have 1273

detected counts in the database at the

minimal threshold level of 2 μg/L. The

national co-occurrence estimates

derived from the USGS NWIS data

revealed several correlations between

arsenic/sulfate and arsenic/iron at the

threshold levels chosen by EPA as likely

to affect treatment (see section VIII.).

First, a significant correlation was

observed between dissolved arsenic and

sulfate in surface water and ground

water samples at the national level. The

analysis of the surface and ground water

data from EPA Regions 1, 2, 4, 5, 6, 7,

8, 9 and 10 show 339 co-occurrence

frequency counts of the data above the

threshold values of dissolved arsenic >5

μg/L and sulfate >250 mg/L (Table V–8).

For total arsenic and sulfate there are

143 co-occurrence frequency counts for

the same threshold levels. There was no

significant co-occurrence of arsenic and

sulfate in EPA Region 3. Secondly, a

correlation was observed between

dissolved arsenic and iron and total

arsenic and iron in surface and ground

waters from EPA Regions 1, 2, 4, 5, 7,

8 and 9 (Table V–8). There are 562 cooccurrence frequency counts of the data

above the threshold levels of dissolved

arsenic >5 μg/L and iron >300 μg/L.

There are 542 co-occurrence frequency

counts of the data above the threshold

values of total arsenic >5 μg/L and iron

>300 μg/L. There was no significant cooccurrence of arsenic and iron in EPA

Regions 3, 6 and 10.

TABLE V–8.—CORRELATION OF ARSENIC WITH SULFATE AND IRON (SURFACE AND GROUND WATERS)

EPA regions Arsenic types (threshold levels >5 μg/L) Correlation elements and their threshold level Frequency

counts

1, 2, 4, 5, 6, 7,

8, 9, 10.

Dissolved Arsenic ......................................................... Sulfate (>250 mg/L) ...................................................... 339

Total Arsenic ................................................................. Sulfate (>250 mg/L) ...................................................... 143

1, 2, 4, 5, 7, 8, 9 Dissolved Arsenic ......................................................... Iron (>300 μg/L) ............................................................ 562

Total Arsenic ................................................................. Iron (>300 μg/L) ............................................................ 542

The results also show some cooccurring pairs of arsenic with radon.

This appears to occur in EPA Regions 5

and 6 for ground water. However, the

co-occurrence of arsenic and radon at

levels of concern is not significant

(Table V–9). At present, the analysis

does not show significant co-occurring

pairs between arsenic and radon in

surface water in any EPA region. The

impact from the co-occurrence of

arsenic and radon is not a concern on

a national level because there was no

significant co-occurring pairs in EPA

Regions 1, 2, 3, 4, 7, 8, 9, and 10. EPA

requests comments on whether the

NWIS database and this analysis is

appropriate to use to represent coVerDate 11<MAY>2000 20:37 Jun 21, 2000 Jkt 190000 PO 00000 Frm 00025 Fmt 4701 Sfmt 4702 E:\FR\FM\22JNP2.SGM pfrm01 PsN: 22JNP2
38912 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

occurrence of arsenic with other

constituents.

TABLE V–9.—CORRELATION OF ARSENIC WITH RADON (GROUND WATER)

EPA

regions Arsenic types and threshold levels (μg/L)

Radon and

threshold

levels(pci/l)

Frequency

counts

5 and 6 ..... Dissolved 2≤5 ........................................................................................................................................... 100≤300 58

300≤1000 140

Dissolved 5≤10 ......................................................................................................................................... 100≤300 124

300≤1000 101

Total 2≤5 ................................................................................................................................................... 0≤100 2

100≤300 2

Total 5≤10 ................................................................................................................................................. 0≤100 1

100≤300 1

VI. Analytical Methods

A. What Section of SDWA Requires the

Agency To Specify Analytical Methods?

Section 1401 of SDWA directs EPA to

promulgate national primary drinking

water regulations (NPDWRs) which

specify either MCLs or treatment

techniques for drinking water

contaminants (42 U.S.C. 300g–1). EPA is

required to set an MCL ‘‘if, in the

judgement of the Administrator, it is

economically and technologically

feasible to ascertain the level of a

contaminant in water in public water

systems’’ (SDWA section 1401(1)(C)(i)).

Alternatively, ‘‘if, in the judgement of

the Administrator, it is not

economically or technologically feasible

to so ascertain the level of such

contaminant,’’ the Administrator may

identify known treatment techniques,

which sufficiently reduce the

contaminant in drinking water, in lieu

of an MCL (SDWA section

1401(1)(C)(ii)). In addition, the NPDWRs

are required to include ‘‘criteria and

procedures to assure a supply of

drinking water which dependably

complies with such maximum

contaminant levels; including accepted

methods for quality control and testing

procedures to insure compliance with

such levels * * *’’ (SDWA section

1401(1)(D))

B. What Factors Does the Agency

Consider in Approving Analytical

Methods?

In deciding whether an analytical

method is economically and

technologically feasible to determine the

level of a contaminant in drinking

water, the Agency considers the

following factors:

• Is the method sensitive enough to

address the level of concern (i.e., the

MCL)?

• Does the method give reliable

analytical results at the MCL? What is

the precision (or reproducibility) and

the bias (accuracy or recovery)?

• Is the method specific? Does the

method identify the contaminant of

concern in the presence of potential

interferences?

• Is the availability of certified

laboratories, equipment and trained

personnel sufficient to conduct

compliance monitoring?

• Is the method rapid enough to

permit routine use in compliance

monitoring?

• What is the cost of the analysis to

water supply systems?

C. What Analytical Methods and

Method Updates Are Currently

Approved for the Analysis of Arsenic in

Drinking Water?

EPA approved analytical methods and

method updates for the analysis of

arsenic in drinking water in previous

rulemakings. EPA took the factors listed

in section VI.B into consideration when

it approved these methods and updates.

The methods and updates, listed in

Table VI–1, are based on atomic

absorption, atomic emission and mass

spectroscopy methodologies and have

been used for compliance monitoring of

arsenic at the 0.05 mg/L MCL by State,

Federal and private laboratories for

many years. In this section on the

discussion of analytical methods, and in

the sections discussing the consumer

confidence rule and public notification,

EPA uses the mg/L units of measure, the

units used in the regulatory language.

Note that EPA’s drinking water

analytical methods refer to mg/L instead

of μg/L, and milligrams are 1,000 times

larger than micrograms.

TABLE VI–1.—APPROVED ANALYTICAL METHODS (AND METHOD UPDATES) FOR ARSENIC (CFR 141.23)

Methodology Reference method 1

MDL 2 or

EDL 3

(mg/L)

Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP–AES) ...................................................... 200.7 (EPA)

3120B (SM)

0.008

3 0.050

Inductively Coupled Plasma Mass Spectroscopy (ICP–MS) ICP–MS with Selective Ion Monitoring ............ 200.8 (EPA) 0.0014 4 (0.0001)

Stabilized Temperature Platform Graphite Furnace Atomic Absorption (STP–GFAA) STP–GFAA with Multiple Depositions.200.9 (EPA) 0.0005 5 (0.0001)

Graphite Furnace Atomic Absorption (GFAA) ................................................................................................. 3113B (SM)

D–2972–93C (ASTM)

3 0.001

3 0.005

Gaseous Hydride Atomic Absorption (GHAA) ................................................................................................. 3114B (SM)

D–2972–93B (ASTM)

3 0.0005

3 0.001

1The reference methods approved for measuring arsenic in drinking water are cited in 40 CFR 141.23. The reference methods include:

EPA = ‘‘Methods for the Determination of Metals in Environmental Samples—Supplement I’’, EPA/600/R–94–111, US EPA, May 1994. (US

EPA, 1994b)

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38913

SM = Standard Methods for the Examination of Water and Wastewater, 18th and 19th eds., Washington, D.C., 1992 and 1995. (APHA, 1992

and 1995 respectively). The 19th edition of SM was approved in the December 1, 1999 final methods rule (64 FR 67450, US EPA 1999j).

ASTM = Annual Book of ASTM Standards: Waster and Environmental Technology,’’ Vol. 11.01 and 11.02, American Society for Testing and

Materials, 1994 and 1996. (ASTM, 1994 and 1996). The 1996 edition of ASTM was approved in the December 1, 1999 final methods rule (64 FR

67450, US EPA 1999j). 2 MDL = Method Detection Limit = ‘‘the minimum concentration of a substance that can be measured and reported with 99% confidence that

the analyte concentration is greater than zero.’’ (40 CFR Part 136 Appendix B). 3EDL = Estimated Detection Limit (EDL) is defined as either the MDL or a concentration of a compound in a sample yielding a peak in the

final extract with a signal to noise ratio of 5, whichever value is greater. Although the ASTM GFAA method (D–2972–93C) has a reported EDL of

0.005 mg/L, this method is similar to other GFAA methods. EPA believes D–2972–93C is capable of detection limits similar to other GFAA methods. 4 In 1994 (59 FR 62456; US EPA, 1994c), the Agency approved the use of the updated ‘‘Methods for the Determination of Metals in Environmental Samples—Supplement I,’’ (US EPA, EPA/600/R–94/111, 1994). The revised manual allows the use of selective ion monitoring with ICP–

MS. The determined MDL for the direct analysis of arsenic in aqueous samples was 0.1 μg/L. 5 In 1994 (59 FR 62456; US EPA, 1994c), the Agency approved the use of the updated ‘‘Methods for the Determination of Metals in Environmental Samples—Supplement I,’’ (US EPA, EPA/600/R–94/111, 1994). The revised manual allows the use of multiple depositions with STP–

GFAA. The determined MDL for arsenic using multiple deposition with STP–GFAA is 0.1 μg/L.

D. Will Any of the Approved Methods

for Arsenic Analysis Be Withdrawn?

EPA believes all of the analytical

methods listed in Table VI–1, with the

exception of EPA Method 200.7 and SM

3120B, are technically and economically

feasible for compliance monitoring of

arsenic in drinking water at the

proposed MCL of 0.005 mg/L. EPA is

proposing to withdraw approval for EPA

Method 200.7 and SM 3120B because

the detection limit for the first ICP–AES

method, 0.008 mg/L, and the estimated

detection limit for the second ICP–AES

method, 0.050 mg/L, are inadequate to

reliably determine the presence of

arsenic at the proposed MCL of 0.005

mg/L. Analysis of the Water Supply

(WS) studies used to derive the PQL

(Analytical Methods Support Document,

US EPA, 1999l) indicates that ICP–AES

technology was rarely used for low level

arsenic analysis. Therefore, the Agency

believes the removal of the methods that

use ICP–AES technologies will not have

an impact on laboratory capacity.

Even at the MCL options of 0.003,

0.010 mg/L, and 0.020 mg/L, the Agency

would still withdraw both EPA Method

200.7 and SM 3120B. At these MCL

options, these methods are still

inadequate for compliance monitoring

of arsenic in drinking water.

E. Will EPA Propose Any New

Analytical Methods for Arsenic

Analysis?

The Agency conducted a literature

search to identify additional analytical

methods which are capable of

compliance monitoring of arsenic at the

proposed MCL of 0.005 mg/L

(Analytical Methods Support Document,

US EPA, 1999l). A large majority of the

analytical techniques identified from

the literature search were from EPA’s

Office of Solid Waste SW–846 methods

manual, which can be accessed online

at www.epa.gov/epaoswer/hazwaste/

test/index.html. Of the Solid Waste

methods, the Agency evaluated:

• SW–846 Method 6020 (ICP–MS,

MDL = 0.0004 mg/L; US EPA, 1994d);

• SW–846 Method 7060A (GFAA,

MDL = 0.001 mg/L; US EPA, 1994e);

• SW–846 Method 7062 (GFAA, MDL

= 0.001 mg/L; US EPA, 1994f);

• SW–846 Method 7063 (Anodic

Stripping Voltammetry-ASV, MDL =

0.0001 mg/L; US EPA, 1996d);

In addition to the SW–846 method,

the Agency also reviewed:

• EPA Method 1632 (a wastewater

GHAA method with an MDL = 0.000002

mg/L or 0.002 μg/L; US EPA 1996a); and

• EPA Method 200.15 (an ICP–AES

with ultrasonic nebulization as part of

the written method, MDL = 0.003 mg/

L or 0.002 mg/L; US EPA, 1994a).

Although the SW–846 methods and

the EPA 1632 wastewater method are

capable of reaching the detection limits

needed at the proposed arsenic MCL,

most of these techniques (with the

exception of the method using ASV

technology) are similar to methods that

have already been approved for the

analysis of arsenic in drinking water.

The Agency does not believe approval

of these methods for drinking water

would provide additional analytical

benefits. Moreover, the addition of the

SW–846 methods could complicate the

laboratory certification process because

SW–846 methods are not mandatory

procedures, but rather guidance. At this

time, laboratories are certified at

different times for different EPA

programs. Therefore, laboratories

certified for both drinking water

methods and Office of Solid Waste

methods may need to be certified

separately under both programs to use

SW–846 methods for drinking water.

While SW–846 Method 7063 (using

ASV technology) is not similar to any

technique approved thus far, this

method will not be approved for the

measurement of arsenic in drinking

water because it only detects dissolved

arsenic as opposed to total arsenic.

Today’s proposal would regulate total

arsenic in drinking water not dissolved

arsenic. The techniques currently

approved for drinking water measure

total arsenic (arsenic species in the

dissolved and suspended fractions of a

water sample). A preliminary total

metals digestion would be necessary

with the ASV technique in order to

determine the total arsenic

concentration in a drinking water

sample.

The Agency also reviewed but does

not propose to approve EPA Method

200.15, an ICP–AES method which

requires the use of ultrasonic

nebulization to introduce the sample

into the plasma. To provide uniform

signal response using EPA Method

200.15, it is necessary for arsenic to be

in the pentavalent state. The addition of

hydrogen peroxide to the mixed acid

solutions of samples and standards prior

to ultrasonic nebulization is necessary

to convert all of the arsenic species to

the pentavalent state. Although EPA

Method 200.15 is capable achieving a

MDL of 0.003 mg/L using direct analysis

and a MDL of 0.002 mg/L using a total

recoverable digestion and a 2-fold

concentration, these levels of detection

are still insufficient for compliance

monitoring at the proposed MCL of

0.005 mg/L.

At the MCL options of 0.010 mg/L and

0.020 mg/L, the Agency would approve

the use of EPA Method 200.15 but only

with the use of a total recoverable

digestion and a 2-fold concentration

(MDL = 0.002 mg/L). At an MCL option

of 0.003 mg/L, EPA method 200.15

would not be approved.

F. Other Method-Related Items

1. The Use of Ultrasonic Nebulization

with ICP–MS

In the September 3, 1998 Analytical

Methods for Drinking Water

Contaminants Proposed Rule (63 FR

47907; US EPA 1998d), EPA proposed

the use of ultrasonic nebulization with

EPA Method 200.7 (ICP–AES) and EPA

Method 200.8 (ICP–MS). Because EPA

Method 200.7 and SM 3120B will be

withdraw for the analysis of arsenic in

drinking water under the proposed MCL

of 0.005 mg/L, ultrasonic nebulization

as a modification would not be allowed.

38914 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

Even with the modification of ultrasonic

nebulization, the ICP–AES method is

not capable of compliance monitoring

for arsenic at the proposed MCL of 0.005

mg/L. EPA Method 200.8 (ICP–MS)

would still be allowed for compliance

monitoring at the proposed MCL of

0.005 mg/L. The use of ultrasonic

nebulization can enhance transport

efficiency and lower the detection limits

for ICP–MS by approximately 5 to 10

fold. The final methods update rule was

published in the Federal Register on

December 1, 1999 (64 FR 67450; US

EPA 1999j).

2. Performance-Based Measurement

System

On October 6, 1997, EPA published a

Notice of the Agency’s intent to

implement a Performance Based

Measurement System (PBMS) in all of

its programs to the extent feasible (62

FR 52098; US EPA, 1997e). EPA is

currently determining how to adopt

PBMS into its drinking water program,

but has not yet made final decisions.

When PBMS is adopted into the

drinking water program, its intended

purpose will be to increase flexibility in

laboratories in selecting suitable

analytical methods for compliance

monitoring, significantly reducing the

need for prior EPA approval of drinking

water analytical methods. Under PBMS,

EPA will modify the regulations that

require exclusive use of Agencyapproved methods for compliance

monitoring of regulated contaminants in

drinking water regulatory programs.

EPA will probably specify ‘‘performance

standards’’ for methods, which the

Agency would derive from the existing

approved methods and supporting

documentation. A laboratory would be

free to use any method or method

variant for compliance monitoring that

performed acceptably according to these

criteria. EPA is currently evaluating

which relevant performance

characteristics under PBMS should be

specified to ensure adequate data

quality for drinking water compliance

purposes. After PBMS is implemented,

EPA may continue to approve and

publish compliance methods for

laboratories that choose not to use

PBMS. After EPA makes final

determinations about the

implementation of PBMS in programs

under the Safe Drinking Water Act, the

Agency would then provide specific

instruction on the specified

performance criteria and how these

criteria would be used by laboratories

for compliance monitoring of SDWA

analytes.

G. What Are the Estimated Costs of

Analysis?

To obtain cost information on the

analysis of arsenic in drinking water,

the Agency collected price information

from a random telephone survey of

seven commercial laboratories, which

were certified in drinking water

analysis, and from price lists posted on

the Internet (Analytical Methods

Support Document, US EPA, 1999l).

Table VI–2 summarizes the results of

this survey, including the specific

methodology and the associated cost

range. The actual costs of performing an

analysis may vary with laboratory, the

analytical technique selected, and the

total number of samples analyzed by a

laboratory. The estimated cost range is

only for the analysis of arsenic and does

not include shipping and handling

costs. The Agency solicits comments

from the public on the cost estimates

listed in Table VI–2.

TABLE VI–2.—ESTIMATED COSTS FOR THE ANALYSIS OF ARSENIC IN DRINKING WATER 1

Methodology

Estimated

cost

range ($)

Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP–AES) ................................................................................................... 15 to 25.

Inductively Coupled Plasma Mass Spectroscopy (ICP–MS) ....................................................................................................................... 10 to 15.

Stabilized Temperature Platform Graphite Furnace Atomic Absorption (STP–GFAA) ............................................................................... 15 to 50.

Graphite Furnace Atomic Absorption (GFAA) ............................................................................................................................................. 15 to 50.

Gaseous Hydride Atomic Absorption (GHAA) ............................................................................................................................................. 15 to 50.

1Analytical Methods Support Document (US EPA, 1999l).

H. What Is the Practical Quantitation

Limit?

Method detection limits (MDLs) and

practical quantitation levels (PQLs) are

two performance measures used by

EPA’s drinking water program to

estimate the limits of performance of

analytic chemistry methods for

measuring contaminants in drinking

water. As cited in Table VI–1, EPA

defines the MDL as ‘‘the minimum

concentration of a substance that can be

measured and reported with 99%

confidence that the analyte

concentration is greater than zero (40

CFR part 136, appendix B).’’ MDLs can

be operator, method, laboratory, and

matrix specific. MDLs are not

necessarily reproducible within a

laboratory or between laboratories on a

daily basis due to the day-to-day

analytical variability that can occur and

the difficulty of measuring an analyte at

very low concentrations. In an effort to

integrate this analytical chemistry data

into regulation development, EPA’s

OGWDW uses the PQL to estimate or

evaluate the minimum, reliable

quantitation level that most laboratories

can be expected to meet during day-today operations. EPA’s Drinking Water

program defined the PQL as ‘‘the lowest

concentration of an analyte that can be

reliably measured within specified

limits of precision and accuracy during

routine laboratory operating conditions

(50 FR 46906, November 13, 1985).’’

1. PQL Determination

A PQL is determined either through

the use of interlaboratory studies or, in

absence of sufficient information,

through the use of a multiplier of 5 to

10 times the MDL. The inter-laboratory

data is obtained from water supply (WS)

performance evaluation (PE) studies that

are conducted twice a year by EPA to

certify drinking water laboratories (now

referred to as the Performance Testing or

PT program). In addition to certification

of drinking water laboratories, WS

studies also provide:

• Large-scale evaluation of analytical

methods;

• A database for method validation;

• Demonstration of method

utilization by a large number of

laboratories; and

• Data for PQL determinations.

Using graphical or linear regression

analysis of the WS data, the Agency sets

a PQL at a concentration where at least

75% of the laboratories (generally EPA

and State laboratories) could perform

within an acceptable level of precision

and accuracy. This method of deriving

a PQL was used in the past for

inorganics such as antimony, beryllium,

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38915

cyanide, nickel and thallium (57 FR

31776 at 31800; US EPA, 1992b).

2. PQL for Arsenic

In 1994, EPA derived a preliminary

PQL for arsenic based on data collected

by the Agency from WS studies 20

through 33 (WS 31 was excluded

because the spiked samples were mixed

incorrectly). In response to concerns

from the water utility industry, the

results of this derivation and a separate

evaluation conducted by the American

Water Works Association (AWWA) were

reviewed by the EPA Science Advisory

Board (SAB) in 1995. The SAB noted

that the acceptance limits of + 40% used

by EPA to derive the PQL in 1994 were

wider than those for other SDWA metal

contaminants. The acceptance limits

and PQLs for several SDWA metals are

shown in Table VI–3. The SAB

recommended that EPA set the PQL

using acceptance limits similar to those

used for other inorganics.

TABLE VI–3.—ACCEPTANCE LIMITS AND PQLS FOR OTHER METALS (IN ORDER OF DECREASING PQL)

Contaminant

Acceptance

limit 1

(percent)

PQL (mg/L) 2

Barium ............................................................................................................................................................................ ±15 0.15

Chromium ...................................................................................................................................................................... ±15 0.01

Selenium ........................................................................................................................................................................ ±20 0.01

Antimony ........................................................................................................................................................................ ±30 0.006

Thallium ......................................................................................................................................................................... ±30 0.002

Cadmium ........................................................................................................................................................................ ±20 0.002

Beryllium ........................................................................................................................................................................ ±15 0.001

Mercury .......................................................................................................................................................................... ±30 0.0005

1Acceptance limits for the listed inorganics are found at CFR 141.23 (k) (3)(ii).

2The PQL for antimony, beryllium and thallium was published in 57 FR 31776 at 31801 (July 17, 1992; US EPA, 1992b). The PQL for barium,

cadmium, chromium, mercury and selenium was published in 66 FR 3526 at 3459 (January 30, 1991; US EPA, 1991a).

Subsequent to SAB’s

recommendation, EPA derived a new

PQL for arsenic (Analytical Methods

Support Document, US EPA, 1999l).

The process employed by the Agency to

determine the new PQL utilized:

• Data from six voluntary, low-level

(<0.006 mg/L of arsenic) WS studies;

• Acceptance limits similar to other

low-level inorganics; and

• Linear regression analysis to

determine the point at which 75% of

EPA Regional and State laboratories fell

within the chosen acceptance range.

The derivation of the PQL for arsenic

was consistent with the process used to

determine PQLs for other metal

contaminants regulated under SDWA

and took into consideration the

recommendations from the SAB. Using

acceptance limits of + 30% and linear

regression analysis of WS studies 30

through 36 (excluding 31) yielded a PQL

of 0.00258 mg/L. The Agency rounded

up to derive a PQL for arsenic of 0.003

mg/L at the ± 30% acceptance limit.

While the PQL represents a stringent

target for laboratory performance, the

Agency believes most laboratories, using

appropriate quality assurance and

quality control procedures, will achieve

this level on a routine basis.

I. What Are the Sample Collection,

Handling and Preservation

Requirements for Arsenic?

The manner in which samples are

collected, handled and preserved is

critical to obtaining valid data. Specific

sample collection, handling and

preservation procedures for SDWA

analytes are outlined in the ‘‘Manual for

the Certification of Laboratories

Analyzing Drinking Water’’ (US EPA,

1997a). For metals such as arsenic, the

certification manual specifies the

following:

• Nitric acid (HNO3 at pH< 2) as the

preservative;

• A maximum sample holding time of

6 months;

• And a sample size of 1 liter,

collected in an appropriately cleaned

plastic or glass container, is suggested.

Currently, arsenic does not have an

entry for preservation, collection, and

holding time. EPA is proposing in this

rule, to revise the table following

§ 141.23(k)(2) to add ‘‘arsenic, Conc.

HNO3 to pH < 2, P or G, and 6 months.’’

EPA requests comment on the

appropriateness of this revision.

While 40 CFR 141.23(a)(4) allows

compositing of up to 5 samples from the

same PWS, the detection limit required

for compositing must be 1⁄5 of the MCL.

Also, compositing for inorganic samples

must be done in the laboratory. Samples

should only be held if the laboratory

detection limit is adequate for the

number of samples being composited. In

any case, the composite is not to exceed

five samples. EPA is adding the test

methods and detection limits for the

approved arsenic analytical methods to

the table following § 141.23(a)(4)(i).

J. Laboratory Certification

1. Background

The ultimate effectiveness of today’s

regulation depends upon the ability of

laboratories to reliably analyze arsenic

at the proposed MCL. The existing

drinking water laboratory certification

program (LCP), which was established

by States with guidance and

recommendations from EPA, requires

that only certified laboratories analyze

compliance samples. External checks of

a laboratory’s ability to analyze samples

of regulated contaminants within

specific limits is the one means of

judging laboratory performance and

determining whether or not to grant

certification. Under a performance

testing (PT) program (formerly known as

the performance evaluation or PE

program), laboratories are required to

successfully analyze PT samples

(contaminant concentrations are

unknown to the laboratory being

reviewed) that are prepared by

appropriate third parties. Successful

participation in a PT program is a

prerequisite for a laboratory to achieve

certification and to remain certified for

analyzing drinking water compliance

samples. Achieving acceptable

performance in these studies of

unknown test samples provides some

indication that the laboratory is

following proper practices.

Unacceptable performance may be

indicative of problems that could affect

the reliability of the compliance

monitoring data.

2. What Are the Performance Testing

Criteria for Arsenic?

The Agency has historically identified

acceptable performance using one of

two different approaches:

(a) Regressions from the performance

of preselected laboratories (using 95

percent confidence limits), or

38916 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

(b) Specified accuracy requirements.

Acceptance limits based on specified

accuracy requirements are developed

from past PE study data. EPA has

traditionally preferred to use the second

(‘‘true value’’) approach because it is the

better indicator of performance and

provides laboratories with a fixed target.

Under this approach, each laboratory

demonstrates its ability to perform

within pre-defined limits. Laboratory

performance is evaluated using a

constant ‘‘yardstick’’ independent of

performance achieved by other

laboratories participating in the same

study. A fixed criterion based on a

percent error around the ‘‘true’’ value

reflects the experience obtained from

numerous laboratories and includes

relationships of the accuracy and

precision of the measurement to the

concentration of the analyte. It also

assumes little or no bias in the

analytical methods that may result in

average reporting values different from

the reference ‘‘true’’ value.

In today’s rulemaking, the Agency is

proposing that the laboratory

certification criteria for arsenic be set at

an acceptance limit of + 30 % at > 0.003

mg/L in § 141.23(k)(3)(ii). Analysis of

water supply data indicate that

laboratory capacity at this level should

be sufficient for compliance monitoring.

At this level, 75 % of EPA Regional and

State laboratories and 62 % of non-EPA

laboratories were capable of achieving

acceptable results. As discussed in the

Analytical Methods Support Document,

(US EPA, 1999l), setting an acceptance

limit of ±20% would have decreased

laboratory capacity. EPA requests

comment on setting the acceptance limit

at the upper range of SAB’s

recommendation.

3. How Often is a Laboratory Required

To Demonstrate Acceptable PT

Performance?

EPA requires that a PT (PE) sample for

chemical contaminants be successfully

analyzed at least once a year using each

method which is used to report

compliance monitoring results. For

arsenic this would require that the

laboratory successfully analyze a PT

(PE) sample using the method which is

used to report the results for compliance

monitoring. Additional guidance on the

minimum quality assurance

requirements, conditions of laboratory

inspections and other elements of

laboratory certification requirements for

laboratories conducting compliance

monitoring measurements are detailed

in the Manual for the Certification of

Laboratories Analyzing Drinking Water,

Criteria and Procedures Quality

Assurance (US EPA, 1997a), which can

be downloaded via the Internet at

‘‘http://www.epa.gov/ogwdw000/

certlab/labindex.html.’’

4. Externalization of the PT Program

(Formerly Known as the PE Program)

Due to resource limitations, on July

18, 1996 EPA proposed options for the

externalization of the PT studies

program (61 FR 37464; US EPA, 1996c).

After evaluating public comment, in the

June 12, 1997 final notice EPA (62 FR

32112; US EPA, 1997c):

‘‘decided on a program where EPA would

issue standards for the operation of the

program, the National Institute of Standards

and Technology (NIST) would develop

standards for private sector PE (PT) suppliers

and would evaluate and accredit PE

suppliers, and the private sector would

develop and manufacture PE (PT) materials

and conduct PE (PT) studies. In addition, as

part of the program, the PE (PT) providers

would report the results of the studies to the

study participants and to those organizations

that have responsibility for administering

programs supported by the studies.’’

EPA has addressed this topic in public

stakeholders meetings and in some

recent publications, including the

Federal Register notices mentioned in

this paragraph. More information about

laboratory certification and PT (PE)

externalization can be accessed at the

OGWDW laboratory certification

website under the drinking water

standards heading (www.epa.gov/

safewater).

VII. Monitoring and Reporting

Requirements

The currently applicable monitoring

requirements for arsenic are different

than the other inorganic contaminants

(IOCs). First of all, arsenic’s MCL and

compliance requirements are found in

§ 141.11, instead of in § 141.62(b).

Monitoring, compliance, and reporting

requirements for arsenic are also

different than the standardized

monitoring framework for the grouped

IOCs (which does not include radon).

EPA is proposing to move arsenic to the

standardized monitoring framework for

IOCs (antimony, asbestos, barium,

beryllium, cadmium, chromium,

cyanide, fluoride, mercury, nickel,

nitrate, nitrite, selenium, and thallium),

including the State reporting and

compliance requirements. Table VII–1

presents a comparison of the existing

and proposed arsenic requirements, in

abbreviated form. For a full picture of

the regulations, you must look at the

regulatory language.

In addition, EPA is proposing to

clarify the regulatory language for

sampling to determine compliance for

inorganics, volatiles and synthetic

organic contaminants.

TABLE VII–1.—COMPARISON OF SAMPLING, MONITORING, AND REPORTING REQUIREMENTS

[This table is not complete for compliance purposes, but provides an overview for readers.]

Requirement Current rule Proposed rule

Compliance with § 141.11(a) .............................. MCL only applies to CWS and compliance is

calculated using § 141.23.

Would link compliance with 50 μg/L with

§ 141.23(l) and would not add NTNCWS.

Compliance with § 141.11(b) .............................. MCL is 0.05 mg/L ............................................ MCL will remain 50 μg/L for CWS serving

10,000 or less until 5 years after publication

of final rule, and be effective for larger systems 3 years after publication of final rule.

New lower MCL in § 141.62.

NTNCWS will be subject to sampling, monitoring and reporting 3 years after publication of final rule, but not subject to increased monitoring after exceedances, nor

to MCL violations.

Monitoring frequency .......................................... Groundwater § 141.23(a)(1) One sample at

each entry point to the distribution system

(sampling point).

No change to § 141.23(a)(1).

Surface water § 141.23(a)(2) One sample at

every entry point to the distribution system

(sampling point).

No change to § 141.23(a)(2).

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38917

TABLE VII–1.—COMPARISON OF SAMPLING, MONITORING, AND REPORTING REQUIREMENTS—Continued

[This table is not complete for compliance purposes, but provides an overview for readers.]

Requirement Current rule Proposed rule

Compositing inorganics ...................................... § 141.23(a)(4) may composite up to 5 samples in the lab; detection limit <1⁄5 of the

MCL.

Adding approved arsenic analytical methods

and detection limits to the table following

§ 141.23(a)(4)(i).

Composite >1⁄5 MCL ........................................... § 141.23(a)(4)(i) take follow-up samples within

14 days of each sampling point in the composite.

Same but § 141.23(a)(4)(i) table will list MCL

and detection limits for arsenic.

Compositing by system size ............................... § 141.23(a)(4)(ii) State may permit

compositing at sampling points within a system serving >3,300 people.

No change to § 141.23(a)(4)(ii).

§ 141.23(a)(4)(ii) State may permit

compositing among different systems, 5-

sample limit, systems serving <3,300 people.

No change to § 141.23(a)(4)(ii).

Resampling composites ..................................... § 141.23(a)(4)(iii) Can use duplicates of the

original sample instead, must be analyzed

and reported to State within 14 days of collection.

No change to § 141.23(a)(4)(iii).

Compliance with § 141.11 CWSs have same requirements, but arsenic monitoring would

move from § 141.23(l) to § 141.23(c).

§ 141.23(l)(1) CWS surface water yearly ......... § 141.23(c)(1) surface water one sample per

compliance point annually.

§ 141.23(l)(2) CWS ground water every three

years..

§ 141.23(c)(1) groundwater one sample at

each sampling point during each compliance period.

Monitoring waivers § 141.23(c) .......................... None currently available for arsenic. ............... § 141.23(c)(2) System may apply to the State.

§ 141.23(c)(3)Must take at least one sample

during waiver, which cannot exceed one

compliance period (9 years).

Minimum data for waivers: Surface water

Ground water All results <MCL. New water

source needs three rounds of monitoring.

.......................................................................... § 141.23(c)(4) at least 3 years. At least 3

rounds of monitoring. At least one sample

must be taken after January 1, 1990.

Once MCL exceeded sampling .......................... § 141.23(m) Supplier must report to State

within 7 days and initiate three additional

samples at the same sampling point within

a month.

§ 141.23(c)(7) exceed MCL as calculated in

(i), go to quarterly monitoring next quarter.

§ 141.31(d) within 10 days of giving public

notice, contact primacy agency.

§ 141.203(b) Tier 2 public notice no later

than 30 days after learning of violation and

repeat every 3 months or at least once a

year if allowed by primacy agency.

Compliance based on less than required number of samples.Not currently specified. .................................... § 141.23(i)(1) for IOCs, § 141.24(f)(15)(i) for

VOCs, and §§ 141.24(h)(11)(i) and (ii) for

SOCs will average based on # samples collected.

Average that determines violation. .....................

State notice ........................................................

Public notice .......................................................

§ 141.23(n) When the 4 analyses, rounded to

the same number of significant figures as

the MCL exceeds the MCL, supplier must

notify the State § 141.31 and give notice to

the public § 141.32. Monitoring frequency

determined by the State must continue until

< MCL in two consecutive samples or until

a variance, exemption, or enforcement action schedule becomes effective.

§ 141.23(i)(5) arsenic will be reported to the

nearest 0.001 mg/L. § 141.23(i)(1) monitoring > annually, running annual average

at sampling point. If less samples taken

than required, compliance is based on average of samples. Any sample below method

detection limit is assigned zero for calculation.

Sampling frequency after MCL compliance

monitoring begun.

...................................................................... § 141.23(i)(2) monitoring annually or less

often if sampling point > MCL.

Confirmation sample .......................................... None currently specified for arsenic ................ If State requires a confirmation sample, then

compliance based on average of the two

samples. If State specifies additional monitoring, compliance based on running annual

average. If less samples taken than required, compliance is based on average of

samples.

Increased monitoring frequency ......................... ...................................................................... § 141.23(f)(1) State may require one within

two weeks.

§ 141.23(c)(8) State can decrease monitoring

after a minimum of 2 quarters for ground

water and 4 quarters for surface water

<MCL.

38918 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

TABLE VII–1.—COMPARISON OF SAMPLING, MONITORING, AND REPORTING REQUIREMENTS—Continued

[This table is not complete for compliance purposes, but provides an overview for readers.]

Requirement Current rule Proposed rule

§ 141.23(f)(1) If >MCL, State can require a

confirmation sample within two weeks.

§ 141.23(f)(3) Average used to determine

compliance with (i). States can delete results with obvious sampling errors.

§ 141.23(g) State may require more frequent monitoring.

New system and new sources ........................... Only mentions waiver eligibility in

§ 141.23(c)(4).

§ 141.23(c)(9) IOCs, § 141.24(f)(22) VOCs,

§ 141.24(h)(20 SOCs, Compliance demonstrated within State-specified time and

sampling frequencies.

Subpart O Consumer Confidence Reports for

CWS.

>50 μg/L annual report § 141.153(d)(6) length

of violation, potential health effects using

Appendix C, actions taken. 25–50 μg/L informational statement per § 141.154(b).

Lowers MCL & adds MCLG to Appendices A

& B to Subpart O–effective 30 days after

final arsenic rule is published, before compliance with lower MCL is in place.

Subpart Q Public Notification for PWS .............. >50 μg/L CWSs Tier 2 annual report

§ 141.203 required October 31, 2000 (if

they are in jurisdictions where the program

is directly implemented by EPA) or on the

date a primacy State adopts the new requirements (not to exceed May 6, 2002)..

§ 141.203(b) Tier 2 public notice no later than

30 days after learning of violation and repeat every 3 months or at least once a year

if allowed by primacy agency.

§ 141.31(d) within 10 days of giving public notice, contact primacy agency.

>5 μg/L CWSs & add NTNCWS to Table 1 of

§ 141.203 to require Tier 2 annual report

§ 141.203 after effective date of arsenic

MCL (3–5 yrs).

A. What Are the Existing Monitoring

and Compliance Requirements?

The arsenic monitoring requirements

appear in 40 CFR 141.23(a). Surface

water systems must collect routine

samples annually and ground water

systems must collect a routine sample

every three years. However, § 141.11(a)

currently only requires community

water systems (CWS) to monitor for

arsenic. EPA understands that some

States also require their non-transient

non-community water systems

(NTNCWS) to collect samples for the

analysis of arsenic as well. Under the

proposal, CWSs would continue to be

allowed to composite samples as

specified in § 141.23(a)(3); however, the

one-fifth arsenic MCL will no longer be

10 μg/L (It will be 1 μg/L).

Sections 141.23(l) through (q) are

currently used to determine compliance

for arsenic. That is, if arsenic is detected

at a concentration greater than the

maximum contaminant level (MCL), the

community water system must collect 3

additional samples within one month at

the entry point to the distribution

system that exceeded the MCL

(§ 141.23(n)). If the average of the four

analyses performed, rounded to one

significant figure, exceeds the MCL, the

system must notify the State; and the

system must provide public notice

(§ 141.23(n)). After public notification,

the monitoring continues at the

frequency designated by the State until

the MCL ‘‘has not been exceeded in two

successive samples or until [the State

establishes] a monitoring schedule as a

condition to a variance, exemption or

enforcement action (§ 141.23(n)).’’

Monitoring waivers are not permitted to

exclude a system from the sampling

requirements under § 141.23(l)–(q)

which currently apply to arsenic.

B. How Does the Agency Plan To Revise

the Monitoring Requirements?

The Agency is proposing to require

CWS and NTNCWSs to monitor for

arsenic using § 141.23(c). This will

make the arsenic monitoring

requirements consistent with the

inorganic contaminants (IOC’s)

regulated under the standardized

monitoring framework. EPA is

proposing that NTNCWSs monitor and

report arsenic results to the State and

public, as a Tier 2 notice in subpart Q,

Public Notification. However, the

Agency is proposing that NTNCWSs not

be required to meet the MCL, unlike the

other inorganics listed in § 141.62(b).

EPA’s analysis for not requiring

NTNCWSs to comply with the MCL is

based on the cost-benefit analysis

discussed later in section XI.C. of this

preamble.

If arsenic exceeds the MCL, the CWS

will be triggered into quarterly

monitoring for that sampling point ‘‘in

the next quarter after the violation

occurred (§ 141.23(c)(7).’’ The State may

allow the system to return to the routine

monitoring frequency when the State

determines that the system is reliably

and consistently below the MCL.

However, the State cannot make a

determination that the system is reliably

and consistently below the MCL until a

minimum of 2 consecutive ground water

or 4 consecutive surface water samples

have been collected (§ 141.23(c)(8)). All

systems must comply with the sampling

requirements, unless a waiver has been

granted in writing by the State

(§ 141.23(c)(6)).

As shown in Table VI–1, the approved

methods can measure to 0.001 mg/L or

below. In order to use the analytical

power of the methods, EPA is proposing

that arsenic data be reported to the

nearest 0.001 mg/L. Therefore, a result

of 0.0055 mg/L would be rounded to

0.006 mg/L, and 0.0145 mg/L would be

rounded to 0.014 mg/L (Figures ending

in ‘‘5’’ rounded down to end on an even

digit and up to an even digit.). During

the writing of this regulation, some

people had asked whether data above

0.01 mg/L could be rounded to one

significant figure because the MCL is

being proposed with one significant

figure. EPA is issuing a clarification to

arsenic reporting in § 141.23(i) to

indicate that arsenic results will be

reported to the nearest 0.001 mg/L. The

significance for compliance purposes

will be that values between 0.010 mg/

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38919

L and 0.014 mg/L will be averaged to

the nearest 0.001 mg/L, and the yearly

average will more closely reflect the

values measured. EPA requests

comment on these clarifications to

reporting requirements.

C. Can States Grant Monitoring

Waivers?

As proposed, States will be able to

grant a 9-year monitoring waiver to a

system (§ 141.23(c)(3)). Waivers of

arsenic sampling requirements must be

based on all analytical results from

previous sampling and a vulnerability

assessment or the assessment from an

approved source water assessment

program (provided that the assessments

were designed to collect all of the

necessary information needed to

complete a vulnerability assessment for

a waiver). States issuing waivers must

consider the requirements in 40 CFR

141.23(c)(2)–(6). In order to qualify for

a waiver, there must be three previous

samples from a sampling point (annual

for surface water and three rounds for

groundwater) with analytical results

reported below the proposed MCL (i.e.,

the reporting limit must be < 0.005 mg/

L). The use of grandfathered data

collected after January 1, 1990 that is

consistent with the analytical

methodology and detection limits of the

proposed regulation may be used for

issuing sampling point waivers. The

existing § 141.23(l)–(q) regulations do

not permit the use of monitoring

waivers. However, a State could now

use the analytical results from the three

previous compliance periods (1993–

1995, 1996–1998, and 1999–2001) to

issue ground water sampling point

waivers. Surface water systems must

collect annual samples so a State could

use the previous 3 years sampling data

(1999, 2000, and 2001) to issue

sampling point waivers. One sample

must be collected during the nine-year

compliance cycle that the waiver is

effective, and the waiver must be

renewed every nine years. Vulnerability

assessments must be based on a

determination that the water system is

not susceptible to contamination and

arsenic is not a result of human activity

(i.e., it is naturally occurring).

Although the approved analytical

methods can measure to 0.005 mg/L, not

all States have required systems to

report arsenic results below 50 μg/L. In

this case, the States would not have

adequate data to grant waivers until

enough data are available to make the

determinations. EPA has compliance

monitoring data from 25 States at 10 μg/

L and below. On the other hand, one

State submitted data to EPA rounded to

tens of μg/L, so some States may not be

able to grant waivers until the data are

reported below the proposed MCL.

EPA believes that some States may

have been regulating arsenic under the

standardized inorganic framework being

proposed today. If so, those States will

have to ensure that existing monitoring

waivers have been granted using data

reported below the new proposed MCL.

Otherwise States will have to notify the

systems of the new lower reporting

requirements that need to be met to

qualify for a waiver for the proposed

MCL.

D. How Can I Determine if I Have an

MCL Violation?

For this proposal, violations of the

arsenic MCL would be determined

under § 141.23(f)–(i). If a system

samples more frequently than annually

(e.g., quarterly), the system would be in

violation if the running annual average

at any sampling point exceeds the MCL

or if any one sample would cause the

annual average to be exceeded

(§ 141.23(i)(1)). If a system conducts

sampling at an annual or less frequent

basis, the system would be in violation

if one sample (or the average of the

initial and State-required confirmation

sample(s)), at any sampling point

exceeds the MCL (§ 141.23(i)(2).

However, States can require more

frequent monitoring per § 141.23(g) for

systems sampling annually or less often.

Therefore, the Agency is proposing to

clarify this section for situations for

IOCs in § 141.23(i)(2)) and the

corresponding sections for volatile and

synthetic organic contaminants

(§§ 141.24(f)(15)(ii) and

141.24(h)(11)(ii), respectively. This

proposal clarifies compliance for

contaminants subject to §§ 141.23(i)(2)),

141.24(f)(15)(ii), and 141.24(h)(11)(ii) by

pointing out that compliance will be

based on the running annual average of

the initial MCL exceedance and

subsequent State-required confirmation

samples. These confirmation samples

may be required at State-specified

frequencies (e.g., quarterly or some

other frequency depending on sitespecific conditions).

In addition, the clarifications to

§§ 141.23(i)(2)), (141.24(f)(15)(ii) and

141.24(h)(11)(ii) address calculation of

compliance when a system fails to

collect the required number of samples.

Compliance (determined by the average

concentration) would be based on the

total number of samples collected. The

Agency expects systems will conduct all

required monitoring. However, some

systems have purposely not collected

the required number of quarterly

samples, and in doing so some avoided

reporting an MCL violation. While these

systems all incurred monitoring and

reporting violations for the uncollected

samples, some systems divided the sum

of the samples taken by four, which

lowered the annual average reported to

below the MCL, avoiding an MCL

violation. The Agency requests

comment on this clarification of

exceedances determined under a Statedetermined monitoring frequency.

For purposes of calculating MCL

annual averages, § 141.23(i)(1) continues

to set all non-detects equal to a value of

zero. However, the Agency realizes that

some States use the detection limit or a

fraction of the detection limit to

calculate an average.

E. When Will Systems Have To

Complete Initial Monitoring?

The rule becomes effective 3 years

after promulgation (about January 1,

2004) for large PWS (serving over

10,000). This will require all GW and

SW systems serving over 10,000 to

complete the initial round of monitoring

by December 31, 2004. However, States

may allow systems, on a case-by-case

basis, 2 additional years to comply with

the MCL if capital improvements are

necessary.

The Agency is proposing a national

finding that capital improvements are

necessary for public water systems

serving less than 10,000, on the basis

that existing treatments are not expected

to be effective in arsenic removal. Table

VII–2 shows the percentage of small

systems with no treatment in place as

well as the percentage of systems which

currently have in place technologies

that can remove arsenic. The data shows

that capital improvements would be

necessary for many systems. The rule

would be effective 5 years after

promulgation (about January 1, 2006) for

systems serving under 10,000. This

would require these small GW systems

to complete the initial round of

monitoring by the December 31, 2007

(’05–’07 compliance period), and small

SW systems to complete the initial

round of monitoring by December 31,

2006. EPA is requesting comment on

whether it is appropriate to make a

national finding that systems serving

less than 10,000 people will need the

two additional years to add capital

improvements in order to comply with

the proposed MCL. The alternative

would require States to issue individual

two-year extensions for these small

systems.

38920 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

TABLE VII–2.—TREATMENT IN-PLACE AT SMALL WATER SYSTEMS (US EPA, 1999E AND US EPA, 1999M)

System size

Percent of systems with no

treatment in

place

Percent of systems with ion exchange in placePercent of systems with coagulation/filtration in

place

Percent of systems with lime

softening in

place

Percent of systems with reverse osmosis

in place

GW SW GW SW GW SW GW SW GW SW

25–100 ............................................................. 50 7 1.7 0 1.7 21.7 2.6 4.3 0 0

101–500 ........................................................... 25 6 1.4 0 4.1 53.3 2.7 8.9 0.5 0

501–1K ............................................................. 25 0 2.9 0 2.4 73.0 2.4 18.9 0 0

1K–3.3K ............................................................ 27 0 1.6 0 2.7 76.4 2.7 16.4 0.4 0

3.3K–10K .......................................................... 26 0 2.1 0 8.1 85.3 3.3 7.4 0.6 0

References: Geometries and Characteristics of Public Water Systems, August 1999, (US EPA, 1999e) Drinking Water Baseline Handbook,

February 24,1999, (US EPA, 1999m)

The regulatory changes affected by the revised arsenic MCL are summarized in Table VII–3.

TABLE VII–3.—TABLE IDENTIFYING REGULATORY CHANGES

CFR citation Topic or subpart

§ 141.23(a)(4) ....................... Sample compositing allowed by the State.

141.23(a)(4)(i) ...................... Detection limit for arsenic.

141.23(a)(5) .......................... Frequency of monitoring for arsenic determined in § 141.23(c).

141.23(c) .............................. Standard inorganic monitoring framework, with State waivers possible.

141.23(f)(1) ........................... Confirmation sampling may be required by the State.

141.23(g) .............................. More frequent monitoring may be required by the State.

141.23(i)(5) ........................... Compliance determination reporting.

141.23(k)(1) .......................... Approved methodology.

141.23(k)(2) .......................... Container, preservation, and holding time.

141.23(k)(3)(ii) ...................... Acceptance limit for certified laboratories.

141.62(b)(16) ........................ MCL for arsenic.

141.62(c) .............................. BATs for arsenic.

141.26(d) .............................. Small system compliance technologies (SSCTs).

141.154(b) ............................ Requires CWS to report exceedances of new MCL in CCR before lower MCL is effective, removing 25–50 μg/L

informational statement requirement.

Appendix A to Subpart O of

141.

Converting lower MCL compliance values for CCRs and listing MCLG.

Appendix B to Subpart O of

141.

Changes MCLG and MCL values effective 30 days after MCL is final.

PN, Subpart Q, Table 1 to

§ 141.203.

Add NTNCWS exceeding MCL (not a violation) to Tier 2 reporting.

Appendix A to Subpart Q of

141.

Public notification regulatory citations revised.

Appendix B to Subpart Q of

141.

Standard Health Effects Language unchanged; revise MCLG, MCL.

In order to prevent the arsenic MCL

of 5 μg/L from becoming effective

immediately, EPA is proposing to delete

the reference to § 141.11(a) in § 141.6(c),

which provides effective dates. While

examining § 141.6(c) for sections that

affect arsenic, we found several sections

that do not exist. Therefore, EPA is

proposing to remove the reference to the

following sections in § 141.6(c) listed in

Table VII–4:

TABLE VII–4.—TABLE LISTING

DELETED SECTIONS

CFR section Topic or reason

141.11(a) ............... New arsenic MCL would

be effective immediately.

141.11(e) ............... Section 141.11(e) does

not exist

TABLE VII–4.—TABLE LISTING

DELETED SECTIONS—Continued

CFR section Topic or reason

141.14(a)(1) .......... Section 141.14 does not

exist.

141.14(b)(1)(i) ....... Section 141.14 does not

exist.

141.14(b)(2)(i) ....... Section 141.14 does not

exist.

141.14(d) ............... Section 141.14 does not

exist.

141.24(a)(3) .......... Section 141.24(a) is reserved.

The Agency requests comment on

whether these deletions to § 141.6(c) are

necessary and appropriate.

F. Can I use Grandfathered Data To

Satisfy the Initial Monitoring

Requirement?

Ground water systems may use

grandfathered data collected after Jan 1,

2002 to satisfy the sampling

requirements for the 2002—2004

compliance period. However, the

detection limit must be less than the

revised MCL. If the grandfathered data

is used to comply with the 2002–2004

compliance period and the analytical

result is between the current MCL and

the revised MCL, then that system will

be in violation of the revised MCL on

the effective date of the rule. If the

system chooses not to use the

grandfathered data, then it must collect

another sample by December 31, 2004 to

demonstrate compliance with the

revised MCL.

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38921

G. What Are the Monitoring

Requirements for New Systems and

Sources?

The current regulations only address

new systems and sources in the waiver

provisions of § 141.23(c)(4), so the

proposal specifically adds monitoring

requirements for these systems for

inorganic, volatile organic, and

synthetic organics contaminants. All

new systems or systems that use a new

source of water that begin operation

after the effective date of this rule would

have to demonstrate compliance with

the MCL within a period of time

specified by the State. The State would

also specify sampling frequencies to

ensure a system can demonstrate

compliance with the MCL. This

requirement would be effective for all

inorganic, volatile organic, and

synthetic organic contaminants

regulated in § 141.23 and § 141.24. The

Agency recognizes that many States

have established requirements for new

systems and new sources, and these are

part of the approved State primacy

programs. Therefore EPA believes that

recognizing State-determined

compliance will be the most effective

way to regulate new systems and

sources. EPA requests comment on this

proposed clarification.

H. How Does the Consumer Confidence

Report Change?

On August 19, 1998, EPA issued

subpart O, the final rule requiring

community water systems to provide

annual reports on the quality of water

delivered to their customers (63 FR

44512; US EPA, 1998e). The first

Consumer Confidence Reports (CCRs)

were required by October 19, 1999. The

next reports are due by July 1, 2000, for

calendar year 1999 data and every July

1 after that (§ 141.152(a)). In general,

reports must include information on the

health effects of contaminants only if

there has been a violation of an MCL or

a treatment technique. For such

violations specific ‘‘health effects

language’’ in subpart O must be

included verbatim in the report. The

arsenic health effects language is

currently required when arsenic levels

exceed 50 μg/L.

In addition, the Agency decided to

require more information for certain

contaminants because of concerns

raised by commenters. One of these

contaminants was arsenic. As explained

in the preamble to the final rule (63 FR

44512 at 44514; US EPA, 1998e) because

of concerns about the adequacy of the

current MCL, EPA decided that systems

that detect arsenic between 0.025mg/L

and the current MCL must include some

information regarding arsenic

(§ 141.154(b)). This informational

statement is different from the health

effects language required for an

exceedance of the MCL. EPA noted that

the requirement would be deleted upon

promulgation of a revised MCL.

Another issue which affects handling

of arsenic in the CCR is the provision in

the statute which authorized the

Administrator to require inclusion of

language describing health concerns for

‘‘not more than three regulated

contaminants’’ other than those detected

at levels which constitute a violation of

an MCL (section 1414(c)(4)(B)(vi)).

Based on stakeholder and commenter

input, the Agency decided in the final

CCR rule that it would use this authority

in future rulemaking to require health

effects language when certain MCLs are

promulgated or revised. The health

effects language of Subpart O would

have to be included in reports of

systems detecting a contaminant above

the level of the new or revised MCL,

prior to the effective date of the MCL,

although technically the systems are not

in violation of the regulations. The

Agency used this authority in the

promulgation of the Disinfectants and

Disinfection Byproducts for one

contaminant, Total Trihalomethanes on

December 16, 1998 (63 FR 69390). The

Agency is now proposing to use this

same authority to require inclusion of

the health effects language in reports of

systems which detect arsenic above the

level of the revised MCL upon

promulgation of these regulations. The

Agency believes that it is important to

provide this information to customers

immediately. The systems have the

flexibility to place this information in

context and explain to customers that

there is no on-going violation.

Furthermore, the health advisory EPA is

planning to issue in the near future will

provide consumers with information

about obtaining sources with lower

arsenic prior to the effective date of the

5 μg/L arsenic MCL. EPA asks for

comment on whether the consumer

confidence report should notify

customers of arsenic health effects

starting with the report issued by July 1,

2002 for calendar year 2001.

After the promulgation date of the

revised arsenic MCL and before the

effective date, community water systems

that detect arsenic above 5 μg/L but

below 50 μg/L would include the

arsenic health effects language. Those

systems that detect arsenic above 50 μg/

L would include the health effects

language and also report violations as

required by § 141.153(d)(6).

I. How Will Public Notification Change?

On May 4, 2000, EPA issued the final

Public Notification Rule (PNR) for

Subpart Q (US EPA 2000c) to revise the

minimum requirements public water

systems must meet for public

notification of violations of EPA’s

drinking water standards and other

situations that pose a risk to public

health from the drinking water. Water

systems must begin to comply with the

new PNR regulations on October 31,

2000 (if they are in jurisdictions where

the program is directly implemented by

EPA) or on the date a primacy State

adopts the new requirements (not to

exceed May 6, 2002). EPA’s arsenic

drinking water regulation affects public

notification requirements and amends

the PNR as part of its rulemaking.

The PNR divides the public notice

requirements into three tiers, based on

the seriousness of the violation or

situation. Tier 1 is for violations and

situations with significant potential to

have serious adverse effects on human

health as a result of short-term

exposure. Notice is required within 24

hours of the violation. Tier 2 is for other

violations and situations with potential

to have serious adverse effects on

human health. Notice is required within

30 days, with extensions up to three

months at the discretion of the State or

primacy agency. Tier 3 is for all other

violations and situations requiring a

public notice not included in Tier 1 and

Tier 2. Notice is required within 12

months of the violation, and may be

included in the consumer confidence

report at the option of the water system.

Today’s proposal will require

community water systems (CWS) to

provide a Tier 2 public notice for

arsenic MCL violations and to provide

a tier 3 public notice for violations of

the monitoring and testing procedure

requirements. Today’s proposal would

also require NTNCWS to provide a Tier

2 notice for exceedances of the MCL. As

later explained in section XI.C., the

Agency believes that overall risks from

water ingested from NTNCWS cannot

justify the costs of treatment. EPA

believes that most States will, using

their authority as described in

§ 141.203(b), require NTNCWS to issue

repeat notices on a yearly basis rather

than every three months. EPA requests

comment on the implementation of

arsenic public notification requirements

by the effective date of the arsenic MCL

and on the Tier 2 public notice

requirement for quarterly repeat notices

for continuing exceedances of the

arsenic MCL for NTNCWS.

38922 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

VIII. Treatment Technologies

Section 1412(b)(4)(E) of the Safe

Drinking Water Act states that each

NPDWR which establishes an MCL shall

list the technology, treatment

techniques, and other means which the

Administrator finds to be feasible for

purposes of meeting the MCL.

Technologies are judged to be a best

available technology (BAT) when the

following criteria are satisfactorily met:

• The capability of a high removal

efficiency;

• A history of full scale operation;

• General geographic applicability;

• Reasonable cost;

• Reasonable service life;

• Compatibility with other water

treatment processes; and

• The ability to bring all of the water

in a system into compliance.

In order to fulfill this requirement set

forth by SDWA, EPA has identified

BATs in Section VIII.A. Their removal

efficiencies and a brief discussion of the

major issues surrounding the usage of

each technology are also given in

section VIII.A. Likely treatment trains,

of which the BAT will be the integral

part, are identified in section VIII. B.

The costs associated with these

treatment trains are also provided. More

details about the treatment technologies

and costs can be found in ‘‘Technologies

and Costs for the Removal of Arsenic

From Drinking Water’’ (US EPA,1999i).

Section 1412(b)(4)(E)(ii) of the Act

also states that EPA shall list any

affordable small systems compliance

technologies that are feasible for the

purposes of meeting the MCL. The

general process by which EPA identifies

compliance, and if necessary, variance

technologies is described in section

VIII.C. The Agency, for the revised

arsenic regulation, is not proposing any

variance technologies. Compliance

technologies for arsenic are identified in

section VIII.E. More details about the

technologies and affordability

determinations can be found in

‘‘Compliance Technologies for Arsenic’’

(US EPA,1999g).

Section VIII.F briefly discusses how

other rules, presently being developed

by the Agency, may impact the arsenic

rule, or how the arsenic rule may impact

these other regulations.

A. What Are the Best Available

Technologies (BATs) for Arsenic? What

Are the Issues Associated With These

Technologies?

EPA reviewed several technologies as

BAT candidates for arsenic removal: ion

exchange, activated alumina, reverse

osmosis, nanofiltration, electrodialysis

reversal, coagulation assisted

microfiltration, modified coagulation/

filtration, modified lime softening,

greensand filtration, conventional iron

and manganese removal, and several

emerging technologies. The Agency

proposes that, of the technologies

capable of removing arsenic from source

water, only the technologies in Table

VIII–1 fulfill the requirements of the

SDWA for BAT determinations for

arsenic. The maximum percent removal

that can be reasonably obtained from

these technologies is also shown in the

table. These removal efficiencies are for

arsenic (V) removal.

TABLE VIII–1.—BEST AVAILABLE

TECHNOLOGIES AND REMOVAL RATES

Treatment technology

Maximum

percent

removal 1

Ion Exchange ................................ 95

Activated Alumina ......................... 90

Reverse Osmosis ......................... >95

Modified Coagulation/Filtration ..... 95

Modified Lime Softening ............... 80

Electrodialysis Reversal ............... 85

1The percent removal figures are for arsenic (V) removal.

In water, the most common valence

states of arsenic are As (V), or arsenate,

and As (III), or arsenite. As (V) is more

prevalent in aerobic surface waters and

As (III) is more likely to occur in

anaerobic ground waters. In the pH

range of 4 to 10, As (V) species

(H2AsO4¥and H2AsO4

2¥) are negatively

charged, and the predominant As (III)

compound (H3AsO3) is neutral in

charge. Removal efficiencies for As (V)

are much better than removal of As (III)

by any of the technologies evaluated,

because the arsenate species carry a

negative charge and arsenite is neutral

under these pH conditions. To increase

the removal efficiency when As (III) is

present, pre-oxidation to the As (V)

species is necessary.

Pre-oxidation. As (III) may be

converted through pre-oxidation to As

(V) using one of several oxidants. Data

on oxidants indicate that chlorine,

potassium permanganate, and ozone are

effective in oxidizing As (III) to As (V).

Pre-oxidation with chlorine may create

undesirable concentrations of

disinfection by-products and membrane

fouling of subsequent treatments such as

reverse osmosis. EPA has completed

research on the chemical oxidants for

As (III) conversion, and is presently

investigating ultraviolet light

disinfection technology (UV) and solid

oxidizing media. For point-of-use and

point-of-entry (POU/POE) devices,

central chlorination may be required for

oxidation of As (III).

Coagulation/Filtration (C/F) is an

effective treatment process for removal

of As (V) according to laboratory and

pilot-plant tests. The type of coagulant

and dosage used affects the efficiency of

the process. Within either high or low

pH ranges, the efficiency of C/F is

significantly reduced. Below a pH of

approximately 7, removals with alum or

ferric sulfate/chloride are similar. Above

a pH of 7, removals with alum decrease

dramatically (at a pH of 7.8, alum

removal efficiency is about 40%). Other

coagulants are also less effective than

ferric sulfate/chloride. Disposal of the

arsenic-contaminated coagulation

sludge may be a concern especially if

nearby landfills are unwilling to accept

such a sludge.

Lime Softening (LS), operated within

the optimum pH range of greater than

10.5 is likely to provide a high

percentage of As removal. However, if

removals greater than 80% are required,

it may be difficult to remove

consistently at that level by LS alone.

Systems using LS may require

secondary treatment to meet that goal

(e.g., addition of an ion exchange unit

as a polishing step). As with C/F,

disposal of arsenic-contaminated sludge

from LS may be an issue.

Coagulation/Filtration and Lime

Softening are technologies primarily

used for large systems. Package plants

may make it more affordable for small

systems to employ these technologies.

Package plants are pre-engineered (i.e.,

the process engineering for the package

plants has been done by the

manufacturer). What remains for the

water system’s engineer to design is the

specifics of the on-site application of the

equipment. However, these technologies

still require well trained operators. If it

is not possible to keep a trained operator

at the plant, an off-site contract operator

may be able to monitor the process with

a telemetry device. Because of these

complexities, these technologies are not

likely to be installed solely for arsenic

removal. However, if they are already in

place, modification of these two

technologies to achieve higher arsenic

removal efficiencies is a viable option.

Activated Alumina (AA) is effective

in treating water with high total

dissolved solids (TDS). However, the

capacity of activated alumina to remove

arsenic is very pH sensitive. High

removals can be achieved at high pHs,

but at shorter run lengths. The use of

chemicals for pH adjustment and bed

regeneration, storage of sulfuric acid

and sodium hydroxide, and process

oversight increase operator

responsibilities and the need for

advanced training. (Decisions on the

certification of water operators will be

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38923

made at the State and local levels).

Operators may have to add an acid to

lower pH to an optimal range and then

afterwards increase the pH to avoid

corrosion. Sodium hydroxide and

sulfuric acid are required in the

regeneration process. Selenium,

fluoride, chloride, sulfate, and silica, if

present at high levels, may compete for

adsorption sites. Suspended solids and

precipitated iron can cause clogging of

the AA bed. Systems containing high

levels of these constituents may require

pretreatment or periodic backwashing.

AA is highly selective towards As (V),

and this strong attraction results in

regeneration problems, possibly

resulting in 5 to 10 percent loss of

adsorptive capacity after each run. As a

result, AA may not be efficient in the

long term. In addition, activated

alumina produces highly concentrated

waste streams, which can contain

approximately 30,000 mg/L of total

dissolved solids (TDS) content. Because

of the high content of TDS in the waste

stream, disposal of the brine must be

taken into consideration.

The safety issue of handling corrosive

and caustic chemicals associated with

this technology may make it

inappropriate for small systems.

Therefore, in estimating national costs,

it was assumed that small systems

would not adjust pH and would not

regenerate on site. Costs were estimated

assuming systems operated a nonoptimal pH and operation on a ‘‘throwaway’’ basis. Regenerating the media offsite instead of disposing of spent media

is another possibility.

Ion Exchange (IX) can effectively

remove arsenic as well. It is

recommended as a BAT primarily for

small, ground water systems with low

sulfate and TDS, and as a polishing step

after filtration. Sulfate, TDS, selenium,

fluoride, and nitrate compete with

arsenic for binding sites and can affect

run length. Column bed regeneration

frequency is a key factor in calculating

costs. Recent research indicates that ion

exchange may be practical up to

approximately 120 mg/L of sulfate

(Clifford 1994). Passage through a series

of columns could improve removal and

decrease regeneration frequency. As

with AA, suspended solids and

precipitated iron can cause clogging of

the IX bed. Systems containing high

levels of these constituents may require

pretreatment. Suspended solids and

precipitated iron may also be removed

by backwashing.

Ion exchange also produces a highly

concentrated waste by-product stream,

and the disposal of this brine must be

considered. Brine recycling can reduce

the amount of waste for disposal and

lower the cost of operation. Recent

research showed that the brine

regeneration solution could be reused as

many as 20 times with no impact on

arsenic removal provided that some salt

was added to the solution to provide

adequate chloride levels for

regeneration (Clifford 1998).

Reverse Osmosis (RO) can provide

removal efficiencies of greater than 95

percent when operating pressure is ideal

(e.g., pounds per square inch, psi).

Water rejection (on the order of 20–

25%) may be an issue in water-scarce

regions. If RO is used by small systems

in the western U. S., water recovery will

likely need to be optimized due to the

scarcity of water resources. Water

recovery is the volume of water

produced by the process divided by the

influent stream (product water/influent

stream). Increased water recovery can

lead to increased costs for arsenic

removal. Since the ability to blend with

an MCL of 5 μg/L would be limited, the

entire stream may have to be treated.

Therefore, most of the alkalinity and

hardness would also be removed. In that

case, to avoid corrosion problems and to

restore minerals to the water, posttreatment corrosion control may be

necessary. Discharge of reject water or

brine may also be a concern.

Electrodialysis Reversal (EDR) can

produce effluent water quality

comparable to reverse osmosis. EDR

systems are fully automated, require

little operator attention, and do not

require chemical addition. EDR systems,

however, are typically more expensive

than nanofiltration and reverse osmosis

systems. These systems are often used

in treating brackish water to make it

suitable for drinking. This technology

has also been applied in the industry for

wastewater recovery. The technology

typically operates at a recovery of 70 to

80 percent. Few studies have been

conducted to exclusively evaluate this

process for the removal of arsenic, but

a removal of approximately 85% can be

expected (US EPA, 1999i).

Other Technologies

Coagulation Assisted Microfiltration.

The coagulation process described

previously can be linked with

microfiltration to remove arsenic. The

microfiltration step essentially takes the

place of a conventional gravity filter.

The University of Houston recently

completed pilot studies at Albuquerque,

New Mexico on iron coagulation

followed by a direct microfiltration

system. The results of this study

indicated that iron coagulation followed

by microfiltration is capable of

removing arsenic (V) from water to yield

concentrations which are consistently

below 2 μg/L. Critical operating

parameters are iron dose, mixing energy,

detention time, and pH (Clifford, 1997).

However, since a full-scale operation

history is one of the requirements to list

a technology as a BAT, it is not

presently being listed as one. It could be

designated as such in the future if the

technology meets that requirement.

Oxidation/Filtration (including

greensand filtration) has an advantage

in that there is not as much competition

with other ions. However, the process

has not been used very much for arsenic

removal. In addition, similar to

activated alumina, greensand filtration

may require pH adjustment to optimize

removal, which may be difficult for

small systems. This technology is not

recommended for high removals. The

maximum removal percentage was

assumed to be 50% when estimating

national costs. The presence of iron in

the source water is critical for arsenic

removal. If the source water does not

contain iron, oxidizing and filtering the

water will not remove arsenic. In

developing national cost estimates, it

was assumed that systems would opt for

this type of technology only if more

than 300 μg/L of iron was present.

Oxidation/Filtration is not being listed

as a BAT because it does not meet the

requirement of a high removal

efficiency. However, since it is a

relatively inexpensive technology, it

may be appropriate for those systems

that do not require much arsenic

removal and have high iron in their

source water.

Emerging Technologies

There are several emerging

technologies for arsenic removal;

however, these require more testing

before they can be designated as a BAT.

Iron-based media products include the

following. Iron oxide coated sand

removes arsenic using adsorption; the

sand also doubles as a filtration media.

The technology has only been tested at

the bench-scale level and may have a

high cost associated with it. Granular

ferric hydroxide also employs an

adsorption process and is being used in

a number of full scale plants in

Germany. Costs may be an issue with

this technology as well. Iron filings are

essentially a filter technology, initially

developed for arsenic remediation.

Though quite effective at remediation,

this technology may have limited use as

a drinking water treatment technology;

the technology performs well when

treating high influent arsenic levels

typical of remediation, but needs to be

proven in treating lower influent levels

expected in raw drinking water to a

finished level at the proposed MCL.

38924 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

Sulfur-modified iron appears to remove

total organic carbon (TOC) and

disinfection byproducts (DBPs) as well

as arsenic. However, it has only been

tested at the bench scale. ADI Group,

Inc.’’s proprietary process also has an

iron-based media that has been installed

in a number of locations.

Nanofiltration is of interest because it

can be operated at lower pressures than

reverse osmosis, which translate into

lower operation and maintenance costs.

However, when nanofiltration is

operated at realistic recoveries, the

removal efficiency appears to be low.

Electrodialysis Reversal (EDR),

although easier to operate than reverse

osmosis and nanofiltration, does not

appear to be competitive with respect to

costs and process efficiency.

Waste Disposal

Waste disposal will be an important

issue for both large and small plants.

Costs for waste disposal have been

added to the costs of the treatment

technologies (in addition to any preoxidation and corrosion control costs),

and form part of the treatment trains

that are listed in Section VIII.B. A

sufficient volume of receiving water

would be needed in order to directly

discharge the contaminated brine stream

from membrane technologies.

Otherwise, operators may have to pretreat to meet Clean Water Act permit

requirements prior to discharge. If the

plant is discharging to a sanitary sewer

because of the membranes, there may be

a very high salinity in the discharge as

well as high levels of arsenic that might,

without pretreatment, exceed local

sewer use regulations. Ion exchange and

activated alumina treatment brines will

be even more concentrated (on the order

of 30,000 TDS), and more than likely

will require pre-treatment prior to

discharge to either a receiving body of

water or the sanitary sewer.

Disposal of solid treatment residuals

would be problematic if they fail the

toxicity characteristic (TC) of the

Resource Conservation and Recovery

Act (RCRA). If they fail the TC, the

residuals are regulated as hazardous

waste because of the concentration of

arsenic. For the purposes of the national

cost estimate, it was assumed that solid

residuals would be disposed of at

nonhazardous landfills.

B. What Are the Likely Treatment

Trains? How Much Will They Cost?

Likely treatment trains are shown in

Table VIII–2. These trains represent a

wide variety of solutions a facility may

consider when complying with the

proposed arsenic MCL. Not all solutions

may be viable for a given system. For

example, only those systems with

coagulation/filtration in-place will be

able to modify their existing treatment

system. The treatment trains include

BATs, waste disposal, and when

necessary, pre-oxidation and corrosion

control.

Table VIII–2 also contains two ‘‘nontreatment’’ options which may be

appropriate if the source water is of very

poor quality. ‘‘Regionalization’’ refers to

connecting with another system and

purchasing water, and ‘‘alternate

source’’ refers to finding a new source

of water (e.g. drilling a new well).

However, since arsenic is a naturally

occurring contaminant, it may be

ubiquitous at a particular site, so

drilling another well may not improve

the situation.

TABLE VIII–2.—TREATMENT TECHNOLOGY TRAINS

Train

No. Treatment technology trains

1 ........................ Regionalization.

2 ........................ Alternate Source.

3 ........................ Add pre-oxidation [if not in-place] and modify in-place Lime Softening.

4 ........................ Add pre-oxidation [if not in-place] and modify in-place Coagulation/Filtration.

5 ........................ Add pre-oxidation [if not in-pace] and add Anion Exchange and add POTW waste disposal and add corrosion control [if >90%

removal required]. Sulfate level at 25 mg/l.

6 ........................ Add pre-oxidation [if not in-place] and add Anion Exchange and add POTW waste disposal and add corrosion control [if

>90% removal required]. Sulfate level at 150 mg/l.

7 ........................ Add pre-oxidation [if not in-place] and add Anion Exchange and add evaporation pond/non-hazardous landfill waste disposal

and add corrosion control [if >90% removal required]. Sulfate level at 25 mg/l.

8 ........................ Add pre-oxidation [if not in-place] and add Anion Exchange and evaporation pond/non-hazardous landfill waste disposal and

add corrosion control [if >90% removal required]. Sulfate level at 150 mg/l.

9 ........................ Add pre-oxidation [if not in-place] and add Activated Alumina and add non-hazardous landfill (for spent media) waste disposal. pH at 7.

10 ...................... Add pre-oxidation [if not in-pace] and add Reverse Osmosis and add direct discharge waste disposal and add corrosion control [if >90% removal required].

11 ...................... Add pre-oxidation [if not in-place] and add Reverse Osmosis and add POTW waste disposal and add corrosion control [if

>90% removal required].

12 ...................... Add pre-oxidation [if not in-place] and add Reverse Osmosis and add chemical precipitation/non-hazardous landfill and add

corrosion control [if >90% removal required].

13 ...................... Add pre-oxidation [if not in-place] and add Coagulation Assisted Microfiltration and add mechanical dewatering/non-hazardous

landfill waste disposal.

14 ...................... Add pre-oxidation [if not in-place] and add Coagulation Assisted Microfiltration and add non-mechanical dewatering/non-hazardous landfill waste disposal.

15 ...................... Add pre-oxidation [if not in-place] and add Oxidation/Filtration (Greensand) and add POTW for backwash stream.

16 ...................... Add pre-oxidation [if not in-place] and add Anion Exchange and add chemical precipitation/non-hazardous landfill waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 25 mg/l.

17 ...................... Add pre-oxidation [if not in-place] and add Anion Exchange and add chemical precipitation/non-hazardous landfill waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 150 mg/l.

18 ...................... Add pre-oxidation [if not in-place] and add Activated Alumina and add POTW/non-hazardous landfill waste disposal. pH at 7.

19 ...................... Add pre-oxidation [if not in-place] and add POE Activated Alumina.

20 ...................... Add pre-oxidation [if not in-place] and add POU Reverse Osmosis.

21 ...................... Add pre-oxidation [if not in-place] and add POU Activated Alumina.

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38925

Costs for each of these treatment

trains are given in Table VIII–3. These

costs are a function of system size. Some

individual systems may experience

household costs higher than those

estimated in this table. The preoxidation costs and corrosion control

costs are given separately for each

system size category because they will

only be incurred by some of the

systems. In estimating national costs, it

was assumed that only systems without

pre-oxidation in-place would add the

necessary equipment. It is expected that

no surface water systems will need to

install pre-oxidation for arsenic

removal. Based on Table IX–4, it is

expected that fewer than 50% of the

ground water systems may need to

install pre-oxidation for arsenic

removal. Ground water systems without

pre-oxidation should determine if preoxidation is necessary by determining if

the arsenic is present as As (III) or As

(V). Groundwater systems with

predominantly As (V) will probably not

need pre-oxidation to meet the MCL.

Similarly, costs for corrosion control

were only added to systems that used

ion exchange or reverse osmosis to

remove more than 90% of the arsenic in

the raw water. It is expected that fewer

than 1% of the affected systems will

need to install corrosion control due to

installation of arsenic treatment. For ion

exchange, different treatment trains

were used for two levels of sulfate. As

sulfate affects regeneration frequency,

the high sulfate treatment train is more

expensive than the low sulfate treatment

train.

TABLE VIII–3.—ANNUAL COSTS OF TREATMENT TRAINS (PER HOUSEHOLD)*

Treatment train

Size

25–100

(dollars)

101–500

(dollars)

501–1000

(dollars)

1001–

3300

(dollars)

3301–

10K

(dollars)

10K–50K

(dollars)

50K–

100K

(dollars)

100K–1M

(dollars)

1 ....................................................................... $ 1347 $ 202 $ 77 $ 25 $ 8 $ 2 $ 1 $ 0

2 ....................................................................... 96 14 5 2 1 0 0 0

3 ....................................................................... 750 138 70 40 30 26 22 18

4 ....................................................................... 462 82 40 22 49 60 38 18

5 ....................................................................... 519 146 90 106 73 55 44 39

6 ....................................................................... 883 248 160 160 78 60 49 44

7 ....................................................................... 629 226 153 154 108 84 71 58

8 ....................................................................... 1227 469 333 290 197 165 135 88

9 ....................................................................... 384 227 201 182 168 152 144 143

10 ..................................................................... 2136 800 555 429 300 256 225 206

11 ..................................................................... 2136 800 555 429 300 256 225 206

12 ..................................................................... 2819 892 572 409 293 237 204 186

13 ..................................................................... 1282 293 195 125 72 50 32 18

14 ..................................................................... 1218 281 187 117 80 54 35 21

15 ..................................................................... 558 156 102 72 55 42 37 31

16 ..................................................................... 1008 222 121 128 86 58 46 40

17 ..................................................................... 1050 246 115 114 96 66 52 45

18 ..................................................................... 427 243 212 192 177 161 153 152

19 ..................................................................... 467 427 408 388 367 342 327 298

20 ..................................................................... 325 289 272 254 236 214 202 178

21 ..................................................................... 377 334 314 292 271 245 230 202

pre-ox** ............................................................ 416 66 26 9 4 2 1 1

corros** ............................................................ 63 17 11 6 5 3 3 3

*These costs are based on a discount rate of 7%.

**The costs for treatment trains 1–21 do not include pre-oxidation or corrosion control costs. For systems that need to add pre-oxidation or corrosion control, the costs for these additional treatments should be added to those of the trains shown in the table.

C. How Are Variance and Compliance

Technologies Identified for Small

Systems?

Section 1415(e)(1) of SDWA allows

States to grant variances to small water

systems (i.e., systems having fewer than

10,000 customers) in lieu of complying

with an MCL if EPA determines that

there are no nationally affordable

compliance technologies for that system

size/water quality combination. The

system must then install an EPA-listed

variance treatment technology (section

1412(b)(15)) that makes progress toward

the MCL, if not necessarily reaching it.

To list variance technologies, three

showings must be made:

(1) EPA must determine, on a national

level, that there are no compliance

technologies that are affordable for the

given small system size category/source

water quality combination.

(2) If there is no nationally affordable

compliance technology, then EPA must

identify a variance technology that may

not reach the MCL but that will allow

small systems to make progress toward

the MCL (it must achieve the maximum

reduction affordable). This technology

must be listed as a small systems

variance technology by EPA in order for

small systems to be able to rely on it for

regulatory purposes.

(3) EPA must make a finding on a

national level, that use of the variance

technology would be protective of

public health and establish.

Primacy States must then make a sitespecific determination for each system

as to whether or not the system can

afford to meet the MCL based on Statedeveloped affordability criteria. If the

State determines that compliance is not

affordable for the system, it may grant

a variance, but it must establish terms

and conditions, as necessary, to ensure

that the variance is adequately

protective of human health.

In the Agency’s draft national-level

affordability criteria published in the

August 6, 1998 Federal Register (US

EPA, 1998h), EPA discussed the

affordable treatment technology

determinations for the contaminants

regulated before 1996. The nationallevel affordability criteria were derived

as follows. First an ‘‘affordability

threshold’’ (i.e., the total annual

household water bill that would be

considered affordable) was calculated.

In developing this threshold value, EPA

considered the percentage of median

38926 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

household income spent by an average

household on comparable goods and

services such items as housing (28%),

transportation (16%), food (12%),

energy and fuels (3.3%), telephone

(1.9%), water and other public services

(0.7%), entertainment (4.4%) and

alcohol and tobacco (1.5%).

Another of the key factors that EPA

used to select an affordability threshold

was cost comparisons with other risk

reduction activities for drinking water.

Section 1412(b)(4)(E)(ii) of the SDWA

identifies both Point-of-Entry and Pointof-Use devices as options for

compliance technologies. EPA

examined the projected costs of these

options. EPA also investigated the costs

associated with supplying bottled water

for drinking and cooking purposes. The

median income percentages that were

associated with these risk reduction

activities were: Point-of-Entry (>2.5%),

Point-of-Use (2%) and bottled water

(>2.5%). The complete rationale for

EPA’s selection of 2.5% as the

affordability threshold is described in

Variance Technology Findings for

Contaminants Regulated Before 1996

(US EPA, 1998f).

Based on the foregoing analysis, EPA

developed an affordability criteria of

2.5% of median household income, or

about $750, for the affordability

threshold (US EPA 1998f). The median

water bill for households in each small

system category was then subtracted

from this threshold to determine the

affordable level of household

expenditures for new treatment. This

difference is referred to as the ‘‘available

expenditure margin.’’ Based on EPA’s

1995 Community Water System Survey,

median water bills were about $250 per

year for small system customers. Thus,

an average available expenditure margin

of up to $500 per year was considered

affordable for the contaminants

regulated before 1996. However, EPA

expects the available expenditure

margin may be lower than $500 per

household per year for the arsenic rule

because EPA believes that water rates

are currently increasing faster than

median household income. Thus, the

‘‘baseline’’ for annual water bills will

rise as treatment is installed for

compliance with regulations

promulgated after 1996, but before the

arsenic rule is promulgated.

To account for this, EPA intends to

adjust its calculation of the baseline for

the affordability criteria as follows. The

national median annual household

water bills for each size category will be

adjusted by averaging the total national

costs for the size category over all of the

systems within the size category. In

other words, the costs incurred by these

rules at the affected water systems will

be averaged over all of the systems in

that size category. A revised available

expenditure margin will be calculated

by subtracting the new baseline from the

affordability threshold. The affordable

technology determinations will be made

by comparing the projected costs of

treatment against the lower available

expenditure margin. If the projected

costs of all treatment technologies for a

given system size/source water quality

exceed the revised available

expenditure margin, then variance

technologies could be considered for

those systems. EPA requests comment

on this method of accounting for new

regulations in its affordability criteria.

Applying the affordability criterion to

the case of arsenic in drinking water,

EPA has determined that affordable

technologies exist for all system size

categories and has therefore not

identified a variance technology for any

system size or source water combination

at the proposed MCL. (See Table IX–12,

Total Annual Costs per Household.) In

other words, annual household costs are

projected to be below the available

affordability threshold for all system

size categories for the proposed MCL.

EPA solicits comment on its

determination in this case as well as its

affordability criteria more generally.

EPA recognizes that individual water

systems may have higher than average

treatment costs, fewer than average

households to absorb these costs, or

lower than average incomes, but

believes that the affordability criteria

should be based on characteristics of

typical systems and should not address

situations where costs might be

extremely high or low or excessively

burdensome. EPA believes that there are

other mechanisms that may address

these situations to a certain extent, such

as rates for disadvantaged communities

and grants. For instance, many utilities

extend special ‘‘lifeline’’ rates to

disadvantaged communities.

EPA also notes that high water costs

are often associated with systems that

have already installed treatment to

comply with a NPDWR. Such treatment

facilities may also facilitate compliance

with future standards. EPA’s approach

to establishing the national-level

affordability criteria did not incorporate

a baseline for in-place treatment

technology. Assuming that systems with

high baseline water costs would need to

install a new treatment technology to

comply with a NPDWR may thus

overestimate the actual costs for some

systems.

To investigate this issue, EPA

examined a group of five small surface

water systems with annual water bills

above $500 per household per year

during the derivation of the nationallevel affordability criteria. All of these

systems had installed disinfection and

filtration technologies to comply with

the surface water treatment rule. If these

systems exceeded the revised arsenic

standard, modification of the existing

processes would be much more costeffective than adding a new technology

to comply with the arsenic rule. These

systems have already made the

investment in treatment technology and

that is reflected in the current annual

household water bills.

In addition, systems that meet criteria

established by the State could be

classified as disadvantaged

communities under section 1452(d) of

the SDWA. They can receive additional

subsidization under the Drinking Water

State Revolving Fund (DWSRF)

program, including forgiveness of

principal. Under DWSRF, States must

provide a minimum of 15% of the

available funds for loans to small

communities and have the option of

providing up to 30% of the grant to

provide additional loan subsidies to the

disadvantaged systems, as defined by

the State.

As previously noted in today’s

proposal, some technologies can

interfere with treatment in-place or

require additional treatment to address

side effects which will increase costs

over the arsenic treatment technology

base costs. (An example is corrosion

control for lead and copper, which may

need to be adjusted to accommodate

other treatment). While EPA tries to

account for such interferences in its cost

estimates for each new compliance

technology, it is not possible to

anticipate all the site specific issues

which may arise. However, EPA has

included a discussion of the cooccurrence of radon, sulfate, and iron in

this proposal. EPA will also provide

guidance identifying cost-effective

treatment trains for ground water

systems that need to treat for both

arsenic and radon after the arsenic rule

is finalized.

EPA encourages small systems to

discuss their infrastructure needs for

complying with the arsenic rule with

their primacy agency to determine their

eligibility for DWSRF loans, and if

eligible, to ask for assistance in applying

for the loans.

D. When Are Exemptions Available?

Under section 1416(a), the State may

exempt a public water system from any

MCL and/or treatment technique

requirement if it finds that (1) due to

compelling factors (which may include

economic factors), the system is unable

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38927

to comply or develop an alternative

supply, (2) the system was in operation

on the effective date of the MCL or

treatment technique requirement, or, for

a newer system, that no reasonable

alternative source of drinking water is

available to that system, (3) the

exemption will not result in an

unreasonable risk to health, and (4)

management or restructuring changes

cannot be made that would result in

compliance with this rule. Under

section 1416(b), at the same time it

grants an exemption the State is to

prescribe a compliance schedule and a

schedule for implementation of any

required control measures. The final

date for compliance may not exceed

three years after the NPDWR effective

date except that the exemption can be

renewed for small systems for limited

time periods.

E. What Are the Small Systems

Compliance Technologies?

Section 1412(b)(4)(E)(ii) of SDWA, as

amended in 1996, requires EPA to issue

a list of technologies that achieve

compliance with MCLs established

under the Act that are affordable and

applicable to typical small drinking

water systems. These small public water

systems categories are: (1) Population of

more than 25 but less than 500; (2)

Population of more than 500, but less

than 3,300; and (3) Population of more

than 3,300, but less than 10,000. Owners

and operators may choose any

technology or technique that best suits

their conditions, as long as the MCL is

met.

Of the treatment trains identified in

section VIII.B., the ones identified in

Table VIII–4 are deemed to be affordable

for systems serving 25–500 people and

the ones identified in Table VIII–5 are

deemed to be affordable for systems

serving 501–3,300 and 3,301–10,000

people, as their annual costs are below

the affordability threshold (US EPA,

1999g). Because affordable compliance

technologies are available, the Agency

does not propose to identify any

variance technologies. EPA requests

comments on the affordable compliance

technology determinations for the three

size categories and the determination

that there will be no variance

technologies. Centralized compliance

treatment technologies include ion

exchange, activated alumina, modified

coagulation/filtration, modified lime

softening, and oxidation/filtration (e.g.

greensand filtration) for source waters

high in iron. In addition, point-of-use

(POU) and point-of-entry (POE) devices

are also compliance technology options

for the smaller systems. EPA is aware

that very few water systems have had

experience with centrally managed POU

or POE options in the past. EPA requests

comments on implementation issues

associated with a centrally managed

POU or POE option for arsenic. The

non-treatment alternatives are especially

relevant for small systems. EPA is

proposing to add the abbreviations

‘‘POU’’ and ‘‘POE’’ to the definitions in

§ 141.2 and asks for comment on the

utility of adding them.

TABLE VIII–4.—AFFORDABLE COMPLIANCE TECHNOLOGY TRAINS FOR SMALL SYSTEMS WITH POPULATION 25–500

Train No. Treatment technology trains

3 ...................................................... Add pre-oxidation [if not in-place] and modify in-place Lime Softening

4 ...................................................... Add pre-oxidation [if not in-place] and modify in-place Coagulation/Filtration

5 ...................................................... Add pre-oxidation [if not in-place] and add Anion Exchange and add POTW waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 25 mg/l.

6 ...................................................... Add pre-oxidation [if not in-place] and add Anion Exchange and add POTW waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 150 mg/l.

7 ...................................................... Add pre-oxidation [if not in-place] and add Anion Exchange and add evaporation pond/non-hazardous

landfill waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 25 mg/l.

8 ...................................................... Add pre-oxidation [if not in-place] and add Anion Exchange and evaporation pond/non-hazardous landfill

waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 150 mg/l.

9 ...................................................... Add pre-oxidation [if not in-place] and add Activated Alumina and add non-hazardous landfill (for spent

media) waste disposal. pH at 7.

15 .................................................... Add pre-oxidation [if not in-place] and add Oxidation/Filtration (Greensand) and add POTW for backwash

stream.

16 .................................................... Add pre-oxidation [if not in-place] and add Anion Exchange and add chemical precipitation/non-hazardous

landfill waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 25 mg/l.

17 .................................................... Add pre-oxidation [if not in-place] and add Anion Exchange and add chemical precipitation/non-hazardous

landfill waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 150 mg/l.

18 .................................................... Add pre-oxidation [if not in-place] and add Activated Alumina and add POTW/non-hazardous landfill waste

disposal. pH at 7.

19 .................................................... Add pre-oxidation [if not in-place] and add POE Activated Alumina.

20 .................................................... Add pre-oxidation [if not in-place] and add POU Reverse Osmosis.

21 .................................................... Add pre-oxidation [if not in-place] and add POU Activated Alumina.

TABLE VIII–5.—AFFORDABLE COMPLIANCE TECHNOLOGY TRAINS FOR SMALL SYSTEMS WITH POPULATIONS 501–3,300

AND 3,301 TO 10,000

Train No. Treatment technology trains

3 ...................................................... Add pre-oxidation [if not in-place] and modify in-place Lime Softening

4 ...................................................... Add pre-oxidation [if not in-place] and modify in-place Coagulation/Filtration

5 ...................................................... Add pre-oxidation [if not in-place] and add Anion Exchange and add POTW waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 25 mg/l.

6 ...................................................... Add pre-oxidation [if not in-place] and add Anion Exchange and add POTW waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 150 mg/l.

7 ...................................................... Add pre-oxidation [if not in-place] and add Anion Exchange and add evaporation pond/non-hazardous

landfill waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 25 mg/l.

8 ...................................................... Add pre-oxidation [if not in-place] and add Anion Exchange and evaporation pond/non-hazardous landfill

waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 150 mg/l.

38928 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

TABLE VIII–5.—AFFORDABLE COMPLIANCE TECHNOLOGY TRAINS FOR SMALL SYSTEMS WITH POPULATIONS 501–3,300

AND 3,301 TO 10,000—Continued

Train No. Treatment technology trains

9 ...................................................... Add pre-oxidation [if not in-place] and add Activated Alumina and add non-hazardous landfill (for spent

media) waste disposal. pH at 7.

10 .................................................... Add pre-oxidation [if not in-place] and add Reverse Osmosis and add direct discharge waste disposal and

add corrosion control [if >90% removal required].

11 .................................................... Add pre-oxidation [if not in-place] and add Reverse Osmosis and add POTW waste disposal and add corrosion control [if >90% removal required].

12 .................................................... Add pre-oxidation [if not in-place] and add Reverse Osmosis and add chemical precipitation/non-hazardous

landfill and add corrosion control [if >90% removal required].

13 .................................................... Add pre-oxidation [if not in-place] and add Coagulation Assisted Microfiltration and add mechanical

dewatering/non-hazardous landfill waste disposal.

14 .................................................... Add pre-oxidation [if not in-place] and add Coagulation Assisted Microfiltration and add non-mechanical

dewatering/non-hazardous landfill waste disposal.

15 .................................................... Add pre-oxidation [if not in-place] and add Oxidation/Filtration (Greensand) and add POTW for backwash

stream.

16 .................................................... Add pre-oxidation [if not in-place] and add Anion Exchange and add chemical precipitation/non-hazardous

landfill waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 25 mg/l.

17 .................................................... Add pre-oxidation [if not in-place] and add Anion Exchange and add chemical precipitation/non-hazardous

landfill waste disposal and add corrosion control [if >90% removal required]. Sulfate level at 150 mg/l.

18 .................................................... Add pre-oxidation [if not in-place] and add Activated Alumina and add POTW/non-hazardous landfill waste

disposal. pH at 7.

19 .................................................... Add pre-oxidation [if not in-place] and add POE Activated Alumina.

20 .................................................... Add pre-oxidation [if not in-place] and add POU Reverse Osmosis.

21 .................................................... Add pre-oxidation [if not in-place] and add POU Activated Alumina.

Centralized treatment is not always a

feasible option. When this is the

situation, home water treatment devices

can be effective and affordable

compliance options for small systems in

meeting the proposed arsenic MCL.

Home water treatment can consist of

either whole-house (point-of-entry) or

single faucet (point-of-use) treatment.

Whole-house, or POE treatment, is

necessary when exposure to the

contaminant by modes other than

consumption is a concern; this is not the

case with arsenic. Single faucet, or POU

treatment, is preferred when treated

water is needed only for drinking and

cooking purposes. POU devices are

especially applicable for systems that

have a large flow and only a minor part

of that flow directed for potable use.

POE/POU options include reverse

osmosis, activated alumina, and ion

exchange processes. POU systems are

easily installed and can be easily

operated and maintained. In addition,

these systems generally offer lower

capital costs and may reduce

engineering, legal, and other fees

associated with centralized treatment

options.

Allowing the usage of POU devices is

one of the new elements of the Safe

Drinking Water Act; on June 11, 1998,

EPA issued a Federal Register notice

(US EPA, 1998i) to withdraw the

prohibition on the use of POU devices

as compliance technologies. The SDWA

stipulates that POU/POE treatment

systems ‘‘shall be owned, controlled and

maintained by the public water system,

or by a person under contract with the

public water system to ensure proper

operation and compliance with the MCL

or treatment technique and equipped

with mechanical warnings to ensure

that customers are automatically

notified of operational problems.’’

Using POU/POE devices introduces

some new issues. Adopting a POU/POE

treatment system in a small community

requires more record-keeping to monitor

individual devices than does central

treatment. POU/POE systems require

special regulations regarding customer

responsibilities and water utility

responsibilities. Use of POU/POE

systems does not reduce the need for a

well-maintained water distribution

system. On the contrary, increased

monitoring may be necessary to ensure

that the treatment units are operating

properly.

Water systems with high influent

arsenic concentrations (i.e., greater than

1 mg/L) may have difficulty meeting the

proposed MCL when POU/POE devices

are used. As a result, influent arsenic

concentration and other source water

characteristics must be considered when

evaluating POU/POE devices for arsenic

removal.

EPA assumed that systems would

more likely opt to use POU AA or RO

(and not IX), and POE AA (and not IX

nor RO), when developing national cost

estimates (refer to Table VIII–4).

Activated alumina and ion exchange

units face a breakthrough issue. If the

media or resin is not replaced and/or

regenerated on time, there is a potential

for significantly reduced arsenic

removal. Activated alumina units have

the advantage of longer run lengths and

the option to use the media once and

throw it away. However, if POE ion

exchange units are regenerated on time,

they would also be an effective

treatment technology. Units with

automatic regeneration are thus viable

options. POE IX and RO units also have

a potential for creating corrosion control

problems. With ion exchange POE units,

a reduction in pH can be expected

initially with new resin, but the pH

reduction should subside over time.

F. How Does the Arsenic Regulation

Overlap With Other Regulations?

Several Federal rules are under

development regarding treatment

requirements that may relate to the

treatment of arsenic for this drinking

water rule. The following briefly

describes each rule, the impact the

Arsenic Rule may have on that rule,

and/or how each rule may impact the

arsenic standard. The Arsenic Rule is

expected to be promulgated in a similar

time frame as the Ground Water Rule,

the Radon Rule, and the Microbial and

Disinfection By-Product Rule (Final

December, 1998). In addition, the

disposal of residuals may be affected by

the hazardous waste regulations of the

Resource Conservation and Recovery

Act (RCRA).

Ground Water Rule (GWR). The goals

of the GWR are to: (1) Provide a

consistent level of public health

protection; (2) prevent waterborne

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38929

microbial disease outbreaks; (3) reduce

endemic waterborne disease; and (4)

prevent fecal contamination from

reaching consumers. EPA has the

responsibility to develop a ground water

rule which not only specifies the

appropriate use of disinfection, but also

addresses other components of ground

water systems to assure public health

protection. This general provision is

supplemented with an additional

requirement that EPA develop

regulations specifying the use of

disinfectants for ground water systems

as necessary. To meet these

requirements, EPA worked with

stakeholders to develop a Ground Water

Rule proposal (US EPA, 2000d) and

plans to issue a final rule by late Fall

2000.

The GWR will result in more systems

using disinfection. Under the GWR, a

system has options other than

disinfection (e.g., protecting source

water). However, if a system does add

a disinfection technology, it may

contribute to arsenic pre-oxidation. This

largely depends on the type of

disinfection technology employed. If a

system chooses a technology such as

ultraviolet radiation, it may not affect

arsenic pre-oxidation. However, if it

chooses chlorination, it will contribute

to arsenic pre-oxidation. As discussed

previously, arsenic pre-oxidation from

As (III) to As (V) will enhance the

removal efficiencies of the technologies.

In addition, systems may use membrane

filtration for the GWR. In that case,

depending on the size of the membrane,

some arsenic removal can be achieved.

Thus, the GWR is expected to alleviate

some of the burden of the Arsenic Rule.

Radon. In the 1996 Amendments to

the SDWA, Congress (section

1412(b)(13)) directed EPA to propose an

MCLG and NPDWR for radon by

August, 1999 (proposed on December

21, 1999, US EPA 1999n) and finalize

the regulation by August, 2000 (section

1412(b)(13)). Like the Ground Water

Rule, the Radon Rule will also be

finalized before the Arsenic Rule.

Systems may employ aeration to comply

with the radon rule. Aeration alone,

however, will not likely be sufficient to

oxidize arsenic (III) to arsenic (V).

However, if systems do aerate, they may

be required by State regulations to also

disinfect. The disinfection process may

oxidize the arsenic, depending on the

type of disinfection employed.

Ultraviolet disinfection may not assist

in arsenic oxidation (still under

investigation by US EPA), whereas

chemical disinfection or oxidation is

likely to. Thus, the Radon Rule is

expected to alleviate some of the burden

of the Arsenic Rule.

Microbial and Disinfection By-product

Regulations. To control disinfection and

disinfection byproducts and to

strengthen control of microbial

pathogens in drinking water, EPA is

developing a group of interrelated

regulations, as required by the SDWA.

These regulations, referred to

collectively as the Microbial

Disinfection By-product (M/DBP) Rules,

are intended to address risk trade-offs

between the two different types of

contaminants.

EPA proposed a Stage 1 Disinfectants/

Disinfection By-products Rule (DBPR)

and Interim Enhanced Surface Water

Treatment Rule (IESWTR) in July 1994.

EPA issued the final Stage 1 DBPR and

IESWTR in November, 1998.

The Agency has finalized and is

currently implementing a third rule, the

Information Collection Rule, that will

provide data to support development of

subsequent M/DBP regulations. These

subsequent rules include a Stage 2

DBPR and a companion Long-Term 2

Enhanced Surface Water Treatment Rule

(LT2ESWTR).

The IESWTR will primarily affect

large surface water systems, so EPA

does not expect much overlap with

small systems treating for arsenic.

However, the Stage 1 DBPR will affect

both large and small sized systems and

may overlap with small systems treating

for arsenic. In addition, the Stage 2

DBPR and possibly the LT2ESWTR

would have significance as far as arsenic

removal is concerned. For systems

removing DBP precursors, systems may

use nanofiltration. The use of

nanofiltration would also be relevant for

removing arsenic, and as a result, would

ease some burden when systems

implement these later rules.

Hazardous Waste. The current

toxicity characteristic (TC) regulatory

level for designating arsenic as a

hazardous waste under the Resource

Conservation and Recovery Act (RCRA)

is 5 mg/L and is listed in 40 CFR

261.24(a). It is important to differentiate

between the toxicity characteristic and

the toxicity characteristic leaching

procedure (TCLP). The TCLP is the

method by which a waste is evaluated

to determine if it exceeds the toxicity

characteristic. It is also important to

note that while the toxicity

characteristic was based on multiplying

the current drinking water MCL by a

factor of 100, the TC is not directly

linked to the drinking water MCL. Thus,

lowering the drinking water MCL does

not mean that the toxicity characteristic

would be lowered. A separate RCRA

rulemaking would be required to lower

the toxicity characteristic regulatory

level. The drinking water standards for

several inorganic contaminants have

been lowered without any lowering of

the toxicity characteristic. For example,

the cadmium MCL was lowered from 10

μg/L to 5 μg/L in 1991, but the TC for

cadmium still remains at 1.0 mg/L. The

drinking water standard for lead was

revised from an MCL of 50 μg/L to an

action level of 15 μg/L. Both drinking

water standards were lowered in 1991.

The TC for lead remains at 5 mg/L. The

studies summarized below show that

arsenic residuals should be below the

current TC of 5 mg/L and could be

disposed in a non-hazardous landfill.

In one study, sludges from four

different water treatment plants were

evaluated. (Bartley et al. 1992). There

are data from two lime softening plants,

one plant with both lime softening and

coagulation/filtration processes, and one

arsenic removal plant utilizing

coagulation/filtration. The raw water

arsenic in the tow lime softening plants

and the one plant using both lime

softening and coagulation/filtration

were below 0.001 mg/L. The arsenic

removal plant was removing arsenic

from 1.1 mg/L to 0.42 mg/L using ferric

sulfate coagulation. The product water

was blended with water from another

source to comply with the MCL. The

TCLP extracts ranged from 0.007 to

0.039 mg/L, which is considerably

below the current criterion for being

designated a hazardous waste under

RCRA.

In another study, TCLP tests were

performed using the activated alumina

from two activated alumina plants

(Wang et al., 2000). Both plants had

similar setups (one is referred to as CS,

the other is referred to as BES). Both

systems consist of four tanks of

activated alumina with two parallel sets

of two tanks in series. The first set of

tanks are used as roughing filters and

the second set of tanks are used as

polishing filters. The units were not

regenerated, but replaced. For the CS

system, the influent arsenic

concentration ranged from 0.053 to

0.087 mg/L with an average of 0.062 mg/

L. The effluent arsenic concentration

was consistently below 0.005 mg/L.

When the activated alumina media was

removed from the roughing filters, three

samples were taken. All three samples

had arsenic TCLP test results of less

than 0.05 mg/L. Again, these results

were well below the regulatory limit.

The influent arsenic concentration of

the activated alumina plant referred to

as BES ranged from 0.021 to 0.076 mg/

L, with an average of 0.049 mg/L.

Effluent levels were also less than 0.005

mg/L. When the media was removed

from the two roughing filters, TCLP tests

were taken. The results were <0.05 mg/

38930 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

L and 0.066 mg/L. Again, the results

were below the regulatory limit.

Another study examined residuals

produced by anion exchange and

coagulation-microfiltration (Clifford,

1997). Experiments were performed at

the University of Houston-US EPA

Drinking Water Research Facility, a 10

ft x 40 ft customized trailer containing

various unit processes, including ion

exchange and coagulationmicrofiltration, and a small analytical

lab. The mobile research facility was set

up at the West Mesa Pump Station in

Albuquerque, NM. The mean arsenic

concentration in the source water was

0.021 mg/L.

Ion exchange was field tested, and the

media was regenerated. This initial

waste stream was a brine from the

regeneration process. The brine in the

ion exchange process was reused 15

times. The average arsenic

concentration in the product was below

0.002 mg/L during the 15 cycles. The

process produced a highly concentrated

spent brine, with arsenic concentrations

reaching 26.6 mg/L. It should be noted

that the arsenic concentration in the

brine would be lower if the brine was

not used as many times. After 6 months

of storage, the arsenic concentration

reduced to 11.3 mg/L. The arsenic was

then precipitated out of the brine using

iron, resulting in a brine with

approximately 0.037 mg/L of arsenic.

The precipitated sludge was then

subjected to the TCLP extraction

procedure. The TCLP extract had an

average arsenic concentration of 0.270

mg/L. This is below the current

threshold for being designated a

hazardous waste.

Coagulation-microfiltration was also

field tested. Arsenic removal to below

0.002 mg/L could be achieved; 12,000

gallons of water were filtered over 3

days. The backwash water, which is the

process waste, had less than 0.5%

solids. According to the TCLP Method

1311, for a liquid waste containing less

than 0.5% solids, the liquid portion of

the waste after filtration, is defined as

the TCLP extract. About 20 backwash

samples were collected, filtered, and

analyzed for arsenic. The average

concentration in the backwash water

after filtration was 0.0026 mg/L and

thus could be disposed as a

nonhazardous waste. Additionally, the

simulated sludge was subjected to the

TCLP leaching procedure. The arsenic

concentration in the TCLP extract was

0.0218 mg/L, which is also considerably

lower than the regulatory limit.

The University of Colorado performed

a series of tests of various arsenic

treatment solid residuals using the

TCLP test (Amy et al, 1999). The arsenic

treatment processes included

conventional plants utilizing lime

softening, alum and ferric chloride

coagulation, activated alumina, and

membranes. The results of this analysis

for the conventional plant residuals are

presented in Table VIII–6. The data

indicates that all the plants would pass

the current TCLP test although the data

from the iron coagulation plant do

approach the limit.

TABLE VIII–6.—TCLP RESULTS FOR CONVENTIONAL PLANT ARSENIC RESIDUALS

Utility ID Type of utility TCLP extract

Arsenic (mg/L)

F, coagulation sludge ............................................................. Lime softening ........................................................................ 0.0009

F, softening sludge ................................................................. Lime softening ........................................................................ 0.0039

F, filter sludge ......................................................................... Lime softening ........................................................................ 0.0014

G ............................................................................................. Lime softening ........................................................................ 0.002

J .............................................................................................. Lime softening ........................................................................ 0.0284

L .............................................................................................. Alum coagulation .................................................................... 0.0093

C ............................................................................................. Fe/Mn removal ....................................................................... 0.0444

O ............................................................................................. Iron coagulation ...................................................................... 1.5596

Table VIII–7 is a summary of TCLP

data on liquid residuals prepared by the

University of Colorado for activated

alumina regenerant and a reverse

osmosis reject water precipitated with

ferric chloride. The activated alumina

regenerant solution was neutralized to a

pH of 6, which caused the aluminum to

precipitate and adsorb the arsenic. The

membrane reject water was treated with

ferric chloride to remove the arsenic and

the resulting ferric hydroxide residual

was tested. The data indicates that solid

residuals generated from the alumina

regenerant and membrane residuals

would pass the TCLP test.

TABLE VIII–7.—TCLP TEST RESULTS

FOR ACTIVATED ALUMINA AND MEMBRANE RESIDUALS

Sample

TCLP

extract

as (mg/L)

Activated Alumina Column

Regenerant ........................... 0.0242

TABLE VIII–7.—TCLP TEST RESULTS

FOR ACTIVATED ALUMINA AND MEMBRANE RESIDUALS—Continued

Sample

TCLP

extract

as (mg/L)

Membrane Filter Reject Residuals .......................................... 0.0179

All of the previous data is from

residuals produced by central treatment.

There is no TCLP data on spent

activated alumina from POU or POE

devices. The TCLP results of spent

activated alumina media from POU and

POE devices were simulated by

assuming a worst-case scenario for 6-

month and one year replacement

frequencies (Kempic, 2000). To

determine the amount of arsenic that

could potentially leach into the

extraction fluid during the toxicity

characteristic leaching procedure, it was

assumed that the influent arsenic

concentration was 0.050 mg/L and that

the activated alumina column adsorbed

all of the arsenic. The first assumption

represents the upper bound for influent

concentrations since it is the current

maximum contaminant level (MCL) for

arsenic. The second assumption means

that there would be no leakage or any

breakthrough of arsenic through the

column, which is not realistic. To

calculate the total adsorbed arsenic

mass, it was assumed that the POU unit

treated 24 liters per day. This is the

upper bound consumption used in the

replacement frequency calculations.

Two other assumptions were made to

simulate the worst-case scenarios. In the

TCLP, the solid phase is extracted with

an amount of extraction fluid equal to

20 times the weight of the solid phase.

The dry media mass was used for the

solid phase for this calculation rather

the wet media mass. It was also

assumed that all of the adsorbed arsenic

would leach into the extraction fluid,

which is not realistic. The estimates for

the worst-case scenarios are provided in

Table VIII–8.

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38931

TABLE VIII–8.—TCLP PROJECTIONS

FOR ACTIVATED ALUMINA WORSTCASE SIMULATIONS

Replacement frequency

Max TCLP

Conc.

(mg/L)

POU & 6-months ...................... 2.6

POE & 6-months ...................... 0.8

POU & Annual .......................... 10.4

POE & Annual .......................... 3.2

The projections for three of the worstcase scenarios were below the TC of 5

mg/L. The worst-case maximum TCLP

concentration for annual replacement

for a POU activated alumina device was

above the TC. However, despite this

projection, activated alumina waste

should be non-hazardous. The most

unrealistic assumption was that all of

the arsenic adsorbed onto the alumina

would leach into the extraction fluid.

The TCLP uses weak acetic acid (0.57%)

at pH 5 for the extraction fluid. The

optimal pH for arsenic adsorption onto

activated alumina is between pH 5.5

and 6.0. Therefore, arsenic should be

retained on the activated alumina at this

pH. In fact, adsorbed arsenic is

extremely difficult to remove under any

conditions. A strong base (4% NaOH) is

typically used to regenerate activated

alumina. Arsenic is so strongly adsorbed

to the activated alumina that only 50 to

70% of the arsenic is eluted during

regeneration. Therefore, it is extremely

unlikely that the spent activated

alumina from POU and POE units

would be considered hazardous.

All of the TCLP data from solid

residuals were below the current TC of

5 mg/L. The arsenic concentrations in

TCLP extracts from alum coagulation,

activated alumina, lime softening, iron/

manganese removal, and coagulationmicrofiltration residuals were below

0.05 mg/L, which is two orders of

magnitude lower than the current TC

regulatory level. The TCLP data for iron

coagulation was mixed—the residuals

from the arsenic removal plant were

below 0.05 mg/L, but the residuals from

another iron coagulation plant were

above 1 mg/L. For anion exchange, the

TCLP data on the precipitated brine

stream was 0.27 mg/L. As was noted,

this was a highly concentrated brine

stream which had been used for fifteen

regenerations. Arsenic concentrations in

the precipitate would be lower if the

brine was used for fewer regeneration

cycles. Based on this data, EPA does not

believe that drinking water treatment

plant residuals would be classified as

hazardous waste. The TCLP data also

indicate that most residuals could meet

a much lower TC regulatory level. EPA

requests comment on whether it is

appropriate to assume that all residuals

can be disposed at a non-hazardous

landfill.

IX. Costs

A. Why Does EPA Analyze the

Regulatory Burden?

EPA is responsible for issuing

regulations that improve the quality of

the nation’s drinking water and reduce

the risk of illness from exposure to

harmful contaminants via drinking

water supplied by public water systems

(PWSs). As part of the regulatory

development process, the Agency is

required to analyze the regulatory cost

and burden imposed on all regulated

and affected entities and the benefits

associated with the regulation. The

Regulatory Impact Analysis (RIA)

document is the principal summary of

these analyses. Assessing the impacts of

proposed SDWA regulations is a

complex process, involving many

analyses specified by various federal

mandates. In particular, EPA must

conduct analyses for the following

mandates:

• 1996 Safe Water Drinking Act

(SDWA) Amendments

• Paperwork Reduction Act (PRA)

• Regulatory Flexibility Act (RFA)

• Small Business Regulatory

Enforcement Fairness Act (SBREFA)

• Unfunded Mandates Reform Act

(UMRA)

• Executive Order (EO) 12866,

‘‘Regulatory Planning and Review’’

• EO 12989, ‘‘Federal Actions to

Address Environmental Justice in

Minority Populations and LowIncome Populations’’

• EO 13045, ‘‘Protection of Children

from Environmental Health Risks and

Safety Risks.’’

Executive Order 12866 describes the

requirements for and content of the

national cost-benefit analyses. Section

1412(b)(3)(C) of SDWA, as amended in

1996, directs EPA to seek comment on

a health risk reduction and cost analysis

(HRRCA) that will be issued with

proposed MCLs. The HRRCA must

identify quantifiable and

nonquantifiable costs and health

benefits of each MCL considered,

including the incremental costs and

benefits of each MCL considered. In

addition, the HRRCA must identify

benefits resulting from reducing cooccurring contaminants and exclude

costs that will result from other

proposed or final regulations. The

Paperwork Reduction Act (PRA)

requires federal agencies to document

the cost and labor burden associated

with data collection, recordkeeping, and

reporting requirements of proposed

regulations. The Regulatory Flexibility

Act (RFA), as amended by the Small

Business Regulatory Enforcement

Fairness Act (SBREFA), mandates that

federal agencies consider the impact

imposed on small businesses,

governments, and non-profit

organizations. The objective of these

mandates is to provide regulatory relief

to small entities affected by SDWA

regulations by identifying alternative or

lower-cost compliance options. Finally,

the Unfunded Mandates Reform Act

(UMRA) seeks to assess the burden and

costs of federal regulations to local and

State governments, while Executive

Order 12989 on environmental justice

instructs federal agencies to evaluate the

impact of proposed regulations on

minority and low-income populations.

Executive Order 13045 requires EPA to

state how the regulation addresses risks

for children.

An RIA attempts to estimate the

possible outcomes in terms of costs and

benefits of various levels of regulation.

At the most basic level, an RIA is built

on estimates of the distribution of

arsenic occurrence among the various

water systems, the costs of treatment

technologies, and predictions of

responses by systems above the

regulatory level under consideration.

Because actual compliance monitoring

at the proposed MCL has not been

required of all systems at the time of

proposal development, projections are

based on statistical estimates. EPA

believes that the current estimates

include appropriate conservative

assumptions and on average actual costs

are not likely to exceed the estimates.

One conservative assumption is that

equipment useful life is identical to

financing life. The Agency has a long

term effort in progress to better

characterize how much this issue will

affect cost estimations.

To be complete, accurate, and

consistent, these analyses should be

based on a single, integrated set of data

and information that defines the

baseline characteristics or conditions of

the regulated community prior to

implementation of the regulation. The

regulated community is primarily the

water supply industry and State, local,

and tribal governments. However, it is

the customers of public water systems,

especially community water systems,

that ultimately incur the cost burden

and realize the intended health benefits

of these regulations. Therefore, the

baseline study identifies and, where

possible, quantifies the universe (e.g.,

characteristics of water suppliers, their

customers, and governmental entities) to

38932 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

be used in the regulatory impact

analysis (RIA).

The current RIA applied national

occurrence information in the modeling

effort as described earlier in section V.G.

EPA requests comment on its analyses

for developing cost projections,

including household costs, as well as

additional cost information. Most

previous RIAs conducted for the

drinking water program assumed that all

the water going into a system was the

same concentration. Actually, many

water systems (especially those serving

more than 500 people) have multiple

points where water enters the

distribution system. Each of these entry

points generally will have a different

level of arsenic. Consequently, water

systems tend to be impacted by

regulations in stages that increase with

decreasing regulatory level. Because

costs are spread across the entire

system, individual household

expenditures will vary according to

regulatory level. Past RIAs were unable

to incorporate this information, and for

costing purposes, all entry points to the

distribution system required treatment.

The arsenic RIA is the first drinking

water chemical RIA to incorporate

monte carlo simulation of intra-system

occurrence variability into the cost and

benefits estimation. This simulation

permits more accurate characterization

of the relative household impacts of

various alternatives. Several other

changes have also been incorporated

into the cost and benefit estimates for

the arsenic RIA:

Very Large Systems—Very large water

systems, those serving more than a

million people, can contribute a

significant portion to estimates of

overall costs and benefits at select

regulatory levels. On the other hand,

because there are so few of these

systems and given that they are of

complex configuration, statistically

based estimates of arsenic occurrence

(especially at low levels of arsenic

incidence) introduce very large

uncertainty into the RIA. EPA addressed

this issue by developing individually

tailored estimates through the use of

generally available occurrence

information and Information Collection

Rule data. Estimates were provided to

the utilities and they were offered the

opportunity to correct errors in the

Agency assessment. While these

estimates are a considerable

improvement over past ones, it is

important to keep in mind that they are

merely projections and that individual

compliance costs could actually still

vary by a wide margin depending upon

rule timing, interactions with other

treatment or capital budget priorities,

regulatory commission decisions, or

actual compliance sampling results.

Inventory Based Modeling—Past RIAs

have generally developed benefit and

cost estimates by estimating impacts for

single representative community water

systems within a limited number of

size-based classes. Such an approach

introduces a slight positive bias to total

national cost estimates. This RIA has

gone beyond the past approach in the

modeling of community water system

and non-transient non-community water

system impacts. This RIA uses a monte

carlo approach to simulate application

of occurrence information to the actual

SDWIS inventory. Through repeated

simulations and assignments, the model

is able to develop the most robust

[statistically defensible] estimates of

actual exposure levels and to better

characterize the spread in household

costs.

B. How Did EPA Prepare the Baseline

Study?

EPA identified baseline

characteristics as the first step in

standardizing baseline profiles and

information for use across all Agency

drinking water RIAs and related

analyses. The Agency has several efforts

underway to develop improved

technical approaches for cost and

benefit analyses, including developing

characteristic engineering unit costs of

treatment plants, assessing financial and

operational capacity, and considering

the low-cost best available treatment

(BAT) options for small systems. Then,

EPA reviewed the analytical procedures,

and data requirements needed to

conduct the analyses.

Table IX–1 provides an overview of

the overall approach for identifying and

classifying specific baseline

characteristics. This matrix organizes

the baseline characteristics according to

the various entities likely to be affected

by SDWA regulations and the different

categories of data analysis inputs. The

affected entities include:

• State and Tribal Governments:

Agencies at the State or local level

(including certain Tribes and Alaskan

Native Villages) responsible for

implementing, administering, and

enforcing drinking water programs, and

other programs potentially affected by

Federal drinking water mandates.

• Public Water Suppliers: Utilities

and other entities that provide potable

water to 25 or more persons, 15 or more

service connections (includes

community and transient/non-transient

non-community water systems).

• Customers: All entities that

purchase drinking water from public

water systems (including residential,

commercial, industrial, wholesale,

governmental, agricultural, and other

users).

The corresponding categories of data

analysis inputs shown in Table IX–1

include:

1. Technical/Operational:

Characteristics relating to capital assets

and operational processes, labor skills

and training, and other variable inputs.

2. Managerial/Organizational:

Characteristics relating to ownership,

control and authority, organizational

structure and management approach.

3. Financial/Economic:

Characteristics relating to monetary

factors, opportunity costs, and benefits.

4. Socio-Economic/Demographic:

Composition and characteristics of

affected entities (who, where, how

much) and demographic trends.

Data to describe all the baseline

conditions shown in Table IX–1 are

contained in a comprehensive EPA

document designed to be applicable to

all drinking water regulatory impact

analyses, ‘‘The Baseline Handbook.’’ It

is data from this document which is

used in Chapter 4 of the RIA for

Arsenic.

1. Use of Baseline Data

Uses of baseline data include the

following analyses:

National and Sub-National Benefits,

Costs, and Economic Impact

Analyses:

• Occurrence Analysis

• Exposure/Risk Assessment

• Model Plants/System Configuration

• Unit Engineering Cost Analysis

• Compliance Decision Tree Analysis

• Financial Analysis

• Government Implementation

• Reporting, Recordkeeping, and

Monitoring Costs

• Valuation of Health Benefits

• Non-Health Benefits Assessment

• Economic Impact Assessment

Small Entity Impact Analyses:

• Small Entity Definition

• Reporting and Recordkeeping

Requirements for Small Entities

• Financial Analysis for Small

Entities

• Socio-Economic Analysis for Small

Entities

• Regulatory Alternatives Analysis

Other Special Analyses:

• Health Risks to Sensitive

Subpopulations

• Affordability Analyses

• Government Budgetary Effects

These broad analytical requirements

reflect the overlapping nature of the

required analyses pursuant to the

relevant statutory and administrative

mandates. For example, various

mandates, including EO 12866, SDWA,

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38933

UMRA, and PRA, require national cost

and benefit analyses.

2. Key Data Sources Used in the

Baseline Analysis for the RIA?

A number of different data sources

were employed in the development of

the tables included Chapter 4 of the

arsenic RIA. The key data sources used

included:

1995 Community Water System Survey

(CWSS). This database was compiled by EPA

from a survey conducted in 1995 to profile

the operational and financial characteristics

of community water systems of all source,

size, and ownership types.

WATER STATS, The Water Utility

Database. This database was compiled by the

American Water Works Association from a

1996 survey of its member utilities. Data on

water system operations and finances were

collected in two stages. The first stage

involved a comprehensive census of the

largest water utilities (i.e., those serving

50,000 or more persons). A second stage data

collection involved a statistical sample of

smaller water utilities.

Safe Drinking Water Information System

(SDWIS). This database serves as the U.S.

EPA’s comprehensive database of public

water system regulatory compliance and

violation information. SDWIS contains the

Agency’s inventory of all public water

supplies, both community and

noncommunity systems and the populations

they serve.

Survey on State Program Staffing/Funding

for FY–97. The Association of State Drinking

Water Administrators (ASDWA) conducted a

survey of State drinking water programs to

solicit estimates on the number of staff (i.e.,

full-time equivalents, FTEs) involved in

drinking water regulatory implementation

and enforcement activities by program area,

as well as estimates of drinking water

program revenues/funding and expenditures

by major account categories.

1990 Census of Population. Data from the

1990 Census of Population was used in

conjunction with water system data to

develop estimates for various demographic

characteristics of households and

communities served by public water systems.

TABLE IX–1.—SUMMARY OF GENERAL BASELINE CATEGORIES OF AFFECTED ENTITIES

Affected entity

Baseline characteristics

1: Technical & operational 2: Managerial & organizational 3: Economic & financial 4: Socioeconomic & demographic

A: State Government ......... A1.1 PWS Inspections &

Sanitary Surveys.

A2.1 Program Staffing ....

A2.2 Laboratory Capacity/Facilities.

A2.3 Division of Authority/Jurisdiction.

A3.1 Program Expenditures.

A3.2 Program Funding/

Revenues.

A4.1 State PWS Profile.

B: Public Water Suppliers B1.1 Water Sources/Intakes.

B1.2 Source Contamination/Protection.

B1.3 Physical Configuration.

B1.4 Plant Condition .......

B1.5 Plant Flow/Capacity

B1.6 Treatment/Waste

Processes In-Place.

B1.7 Storage Capacity ...

B1.8 Distribution System

B1.9 Residence Time .....

B1.1 Monitoring/Laboratory.

B2.1 Ownership/Organizational Structure.

B2.2 Plant Operation/Operators.

B3.1 Operating Expenses

B3.2 Operating Revenues.

B3.3 Non-Operating Expenses.

B3.4 Assets & Liabilities

B3.5 Rate Structures/

User Burden.

B3.6 Capital Investment

Expenditure.

B4.1 PWS Type.

B4.2 PWS Size/Customer Base.

B4.3 PWS Source Water.

B4.4 Geographic Location.

C: Customers .................... C1.1 POU/POE Systems

In Use.

C2.1 Alternative Water

Use.

C2.2 Public Attitudes/

Perceptions.

C3.1 Residential Income

C3.2 Nonresidential Income.

C3.3 Residential Water

Costs.

C3.4 Nonresidential

Water Costs.

C3.5 Cost of Drinking

Water Alternatives.

C3.6 Medical Costs ........

C3.7 Non-Medical Costs

C3.8 Community Financial Information.

C4.1 Population Profile.

C4.2 Customer Water

Use.

C. How Were Very Large System Costs

Derived?

EPA must conduct a thorough costbenefit analysis, and provide

comprehensive, informative, and

understandable information to the

public about its regulatory efforts. As

part of these analyses, EPA evaluated

the regulatory costs of compliance for

very large systems, who would be

subject to the new arsenic drinking

water regulation. The nation’s 25 largest

drinking water systems (i.e., those

serving a million people or more)

supply approximately 38 million people

and generally account for about 15 to 20

percent of all compliance-related costs.

Accurately determining these costs for

future regulations is critical. As a result,

EPA has developed compliance cost

estimates for the arsenic and radon

regulations for each individual system

that serves greater than 1 million

persons. These cost estimates help EPA

to more accurately assess the cost

impacts and benefits of the arsenic

regulation. The estimates also help the

Agency identify lower cost regulatory

options and better understand current

water systems’ capabilities and

constraints.

The system costs were calculated for

the 24 public water systems that serve

a retail population greater than 1

million persons and one public water

38934 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

system that serves a wholesale

population of 16 million persons. Table

IX–2 lists these 25 public water systems.

The distinguishing characteristics of

these very large systems include:

(1) A large number of entry points

from diverse sources;

(2) mixed (i.e., ground and surface)

sources;

(3) Occurrence not conducive to

mathematical modeling;

(4) Significant levels of wholesaling;

(5) Sophisticated in-place treatment;

(6) Retrofit costs dramatically

influenced by site-specific factors; and

(7) Large amounts of waste

management and disposal which can

contribute substantial costs.

TABLE IX–2.—LIST OF LARGE WATER SYSTEMS THAT SERVE MORE THAN 1 MILLION PEOPLE

PWS ID # Utility name

1 ....................................................... AZ0407025 Phoenix Municipal Water System.

2 ....................................................... CA0110005 East Bay Municipal Utility District.

3 ....................................................... CA1910067 Los Angeles—City Dept. of Water and Power.

4 ....................................................... CA1910087 Metropolitan Water District of Southern California.

5 ....................................................... CA3710020 San Diego—City of.

6 ....................................................... CA3810001 San Francisco Water Department.

7 ....................................................... CA4310011 San Jose Water Company.

8 ....................................................... CO0116001 Denver Water Board.

9 ....................................................... FL4130871 Miami-Dade Water And Sewer Authority—Main System.

10 ..................................................... GA1210001 City of Atlanta.

11 ..................................................... IL0316000 City of Chicago.

12 ..................................................... MA6000000 Massachusetts Water Resource Authority.

13 ..................................................... MD0150005 Washington Suburban Sanitation Commission.

14 ..................................................... MD0300002 Baltimore City.

15 ..................................................... MI0001800 City of Detroit.

16 ..................................................... MO6010716 St. Louis County Water County.

17 ..................................................... NY5110526 Suffolk County Water Authority.

18 ..................................................... NY7003493 New York City Aqueduct System.

19 ..................................................... OH1800311 City of Cleveland.

20 ..................................................... PA1510001 Philadelphia Water Department.

21 ..................................................... PR0002591 San Juan Metropolitano.

22 ..................................................... TX0570004 Dallas Water Utility.

23 ..................................................... TX1010013 City of Houston—Public Works Department.

24 ..................................................... TX150018 San Antonio Water System.

25 ..................................................... WA5377050 Seattle Public Utilities.

Generic models cannot incorporate all

of these considerations; therefore, indepth characterizations and cost

analyses were developed utilizing

several existing databases and surveys.

The profile for each system contains

information such as design and average

daily flows, treatment facility diagrams,

chemical feed processes, water quality

parameters, system layouts, and intake

and aquifer locations. System and

treatment data were obtained from the

following sources:

(1) The Information Collection Rule

(1997);

(2) The Community Water Supply

Survey (1995);

(3) The Association of Metropolitan

Water Agencies Survey (1998);

(4) The Safe Drinking Water

Information System (SDWIS); and

(5) The American Water Works

Association WATERSTATS Survey

(1997).

While these sources contained much

of the information necessary to perform

cost analyses, the Agency was still

missing some of the detailed arsenic

occurrence data in these large water

systems. Where major gaps existed,

especially in groundwater systems,

occurrence data obtained from the

States of Texas, California, and Arizona,

the Metropolitan Water District of

Southern California Arsenic Study

(1993), the National Inorganic and

Radionuclides Study (EPA, 1984), and

utilities were used. Based on data from

the studies, detailed costs estimates

were derived for each of the very large

water systems.

Cost estimates were generated for

each system at several MCL options.

The total capital costs and operational

and maintenance (O & M) costs were

calculated using the profile information

gathered on each system, conceptual

designs (i.e., vendor estimates and RS

Means), and modified EPA cost models

(i.e., Water and WaterCost models). The

models were modified based on the

general cost assumptions developed in

the Phase I Water Treatment Cost

Upgrades (EPA, 1998).

Preliminary cost estimates were sent

to all of the systems for their review.

Approximately 30% of the systems

responded by submitting revised

estimates and/or detailed arsenic

occurrence data. Based on the

information received, EPA revised the

cost estimates for those systems. Based

on the results, the majority of the very

large systems will not have capital or

O&M expenditures for complying with a

MCL of 5 μg/L (Table IX–3). More

detailed costs estimates for each very

large water system can be found in the

water docket.

TABLE IX–3.—TOTAL ANNUAL COSTS

FOR LARGE SYSTEMS FOR (SERVING

MORE THAN 1 MILLION PEOPLE)

MCL option

(μg/L)

Number

systems

treating

Cost

[$millions] 1

3 ........................ 3 $16–18

5 ........................ 3 11–12

10 ...................... 3 6.6–7.47

20 3 2.6–2.7

1The lower number shows costs annualized

at 3%; the higher number shows costs

annualized at 7% capital costs. The 7% rate

represents the standard discount rate preferred by OMB for benefit-cost analyses of

government programs and regulations.

D. How Did EPA Develop Cost

Estimates?

EPA developed national cost

estimates by using the occurrence data,

unit cost curves, and a decision tree.

The occurrence data provides a measure

of the number of systems that would

need to install treatment in each size

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38935

category (the occurrence data was

described in Section V). The unit cost

curves provide a measure of how much

a technology will cost to install. Unit

cost curves are continuous functions;

they are a function of system size and

provide an estimated cost for all design

and average flows. The costs for a

treatment train for the average flow in

each size category were given

previously in Table VIII–3. The unit cost

curves can be found in ‘‘Technologies

and Costs for the Removal of Arsenic

From Drinking Water’’ (US EPA, 1999i).

EPA then developed a decision tree,

which is a prediction of what treatment

technology trains facilities would likely

install to comply with options

considered for the revised arsenic

standard. A brief discussion of this

decision tree follows. A copy of the full

300+ page flowchart and supporting

documentation can be found in

‘‘Decision Tree for the Arsenic

Rulemaking Process’’ (US EPA, 1999d).

The following figure is a brief

representation of this flowchart. As

shown in the flowchart, EPA considered

the impact of (1) MCL option and

influent arsenic concentration; (2)

system size; (3) regional effects (water

scarcity); (4) source water type (that is,

ground water or surface water); (5)

existing treatment in-place; (6) waste

disposal issues and costs; and (7) cooccurrence of iron and sulfate, to

estimate what systems are likely to

install.

Ultimately, the decision tree was

expressed in decision matrices, in

which EPA assigned probabilities as to

how often each of the treatment trains

in Table VIII–2 will likely be used. EPA

developed a different decision matrix

for the eight system size categories, for

three different removal efficiencies

(<50%, 50–90% and >90%), and for two

source waters (ground and surface). In

general, to the extent possible (e.g.,

based on source water quality), EPA

assumed that systems would employ the

least-cost technology that can meet the

MCL option.

BILLING CODE 6560–50–P

38936 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

BILLING CODE 6560–50–C

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38937

MCL option. EPA developed a

decision tree that accounted for

treatment technology limitations, and

only assigned non-zero probabilities in

the matrices to those technologies

capable of reaching each MCL option.

The maximum removal percentages are

given in Table VIII–1. For instance,

since greensand filtration is only

assumed capable of removing 50% of

the influent arsenic, for an influent level

of 20 μg/L, the technology is assumed to

be capable of only producing product

water with 10 μg/L of arsenic. Therefore,

for an MCL option of 5 μg/L, no usage

was assumed for greensand filtration at

a 20 μg/L level of influent arsenic.

System size. The decision tree also

depends on system size. For instance,

small systems are assumed to operate

activated alumina on a throw-away

basis, and thus the probability of using

a treatment train that employs on-site

regeneration is assumed to be zero. The

converse is true for large systems; nonzero probabilities are assumed only for

those trains that employ regeneration

on-site.

Water scarcity. Water scarcity was

also taken under consideration when

developing the decision tree. It was

assumed that this issue would adversely

affect the selection of reverse osmosis,

since the technology rejects a significant

portion of the influent water. However,

the costs for reverse osmosis treatment

trains are much higher than others (refer

to Table VIII–3), and systems would

likely opt for other, less expensive,

treatment options. For the range of MCL

options considered, it was assumed that

ion exchange would be capable of

delivering the required removal

efficiencies. Thus, water scarcity,

though considered in the decision tree,

did not affect percentages assigned to

reverse osmosis.

Source water type. Source water type

is also a factor in the decision tree. It

affects the unit cost curves; one set of

curves were developed for surface

water, and another was developed for

ground water. The treatment-in-place

data and co-occurrence data (as shown

below) are sorted by source water type.

Also, certain technologies are

considered appropriate for one source

water type, but not the other. For

instance, greensand filtration is

considered relevant only for ground

waters.

Existing treatment in-place.

Treatments that may already exist at

facilities were taken into account in the

decision tree. It was assumed that

systems would need to pre-oxidize, if

they weren’t doing so already. Table IX–

4 shows the number of systems that

were assumed to require addition of preoxidation (Source: US EPA,1999e).

TABLE IX–4.—SYSTEMS NEEDING TO

ADD PRE-OXIDATION

System size

Percent of

ground

water systems

Percent of

surface

water systems

25–100 .............. 54 9

101–500 ............ 30 4

501–1K ............. 24 0

1,001–3.3K ....... 24 0

3,301–10K ........ 27 3

10,001–50K ...... 13 1

50,001–100K .... 41 2

100,001–1 M ..... 16 0

It was also assumed that those

systems that had coagulation/filtration

in place, or lime softening in place,

would modify those treatments to

optimize for arsenic removal, since it is

a relatively inexpensive option. The

percent of systems with these treatments

in place is given in Table IX–5 (Source:

US EPA,1999e). However, for higher

removals (>90%), it was assumed that

only half of the systems would be able

to achieve the desired removal with a

modification. For those systems, an

additional cost of a polishing step, such

as ion exchange, was added.

TABLE IX–5.—PERCENT OF SYSTEMS WITH COAGULATION-FILTRATION AND LIME-SOFTENING IN PLACE

System size

Percent of

ground water

systems with

CF in place

Percent of surface water

systems with

CF in place

Percent of

ground water

systems with

LS in place

Percent of surface water

systems with

LS in place

25–100 ............................................................................................................. 2 22 3 4

101–500 ........................................................................................................... 4 53 3 9

501–1K ............................................................................................................. 2 73 2 19

1,001–3.3K ....................................................................................................... 3 76 3 16

3,301–10K ........................................................................................................ 8 85 3 7

10,001–50K ...................................................................................................... 4 92 5 8

50,001–100K .................................................................................................... 4 85 3 5

100,001–1 M .................................................................................................... 5 94 10 5

Waste disposal issues and costs.

Waste disposal of arsenic contaminated

sludges and brines was also factored

into the decision tree, and waste costs

were added to the treatment trains. The

waste disposal options for each of the

technologies considered are given in

Table IX–6. For ion exchange and

activated alumina, it was assumed that

the waste streams would be too

concentrated to discharge directly. For

these technologies, it was assumed that

some of the smallest systems would be

able to take advantage of evaporation

ponds, but that this option would be

cost prohibitive in medium and large

systems. It was assumed that most

systems would opt for either chemical

precipitation or discharge to a sanitary

sewer. EPA also assumed that systems

would dispose of spent activated

alumina media in non-hazardous

landfills. Costs for reverse osmosis are

prohibitive (In Table VIII–3, Annual

Costs of Treatment Trains, compare

lines 11, 12, and 13 against other

technologies), but if used, EPA assumed

the relatively large amount of reject

water would be discharged directly

(because it would not be as concentrated

as ion exchange and activated alumina

waste streams), to a sanitary sewer or by

chemical precipitation. For coagulation

assisted microfiltration, modified

coagulation filtration, and modified

lime softening, EPA assumed the waste

would be discharged to non-hazardous

landfills after the sludge is mechanically

or non-mechanically dewatered. For

greensand filtration, it was assumed that

the spent media would be disposed of

in a non-hazardous landfill.

38938 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

TABLE IX–6.—WASTE DISPOSAL OPTIONS

Treatment tech

POTW

waste disposalEvap pond Non-haz

landfill

Direct dischargeChemical

precip

Mech

dewater

Non-mech

dewater

Ion Exchange ........................................... ✔✔ ✔

Activated Alumina .................................... ✔✔✔ ✔

Reverse Osmosis ..................................... ✔ ✔✔

Coag Assisted Micro-filtration .................. ✔ ✔✔

Greensand ............................................... ✔

Modify CF ................................................. ✔ ✔✔

Modify LS ................................................. ✔ ✔✔

Co-occurrence of iron and sulfate.

EPA also factored into the decision tree

co-occurrence data on iron and sulfate

(shown in Tables IX–7 to IX–10, Source:

US EPA,1999f ). Co-occurrence of

sulfate in water adversely affects the

performance of ion exchange, and

increases operation and maintenance

costs. Three sulfate-level treatment

trains were costed for ion exchange: one

low-level, one mid-level and one highlevel. The percentages in Tables IX–7 to

IX–8 were used as ceilings in national

cost estimates and limited the number

of systems that could be placed in the

decision matrices in the low-level and

mid-level sulfate ranges. For example,

the co-occurrence data shows that the

maximum number of systems that can

be costed at the low-level sulfate

treatment train for an influent level of

arsenic between 10 and 20 μg/L is 35%.

If more systems were to be placed in the

decision matrices under ion exchange,

no more than 39% were assumed to face

a sulfate level between 25 and 120 mg/

L. Any more systems assigned to ion

exchange in the decision matrices were

assumed to face high sulfate levels.

TABLE IX–7.—GROUND WATER: ARSENIC AND SULFATE

Influent arsenic

Likelihood of sulfate

(percent)

<25 mg/L 25–120 mg/

L >120 mg/L

<10 μg/L ................................................................................................................................................... 48 33 19

10–20 μg/L ............................................................................................................................................... 35 39 26

>20 μg/L ................................................................................................................................................... 33 38 30

TABLE IX–8.—ARSENIC WATER: ARSENIC AND SULFATE

Influent arsenic

Likelihood of sulfate

(percent)

<25 mg/L 25–120 mg/

L >120 mg/L

<10 μg/L ................................................................................................................................................... 28 32 40

10–20 μg/L ............................................................................................................................................... 20 30 51

>20 μg/L ................................................................................................................................................... 12 28 60

TABLE IX–9.—GROUND WATER: ARSENIC AND IRON

Influent arsenic

Likelihood of sulfate

(percent)

<300 μg/L >300 μg/L

<10 μg/L ........................................................................................................................................................................... 82 18

10–20 μg/L ....................................................................................................................................................................... 81 19

>20 μg/L ........................................................................................................................................................................... 71 29

TABLE IX–10.—SURFACE WATER:

ARSENIC AND IRON

Influent arsenic

Likelihood of sulfate

(percent)

<300 μg/L >300 μg/L

<10 μg/L ........... 91 9

10–20 μg/L ........ 92 8

>20 μg/L ........... 90 10

Co-occurrence of iron in water

improves the performance of greensand

filtration. Greensand is relatively

inexpensive for small systems to use,

but not as effective as other treatment

technologies. It was assumed that

systems would opt for greensand

filtration only if the level of iron was

greater than 300 μg/L. EPA used the cooccurrence data in Tables IX–9 to IX–10

to determine the ceiling on the number

of systems that could use greensand

filtration in the decision matrices.

E. What Are the National Treatment

Costs of Different MCL Options?

Under the proposed option of 5 μg/L,

the Agency estimates that annual

treatment costs to community water

systems will be $374 million per year.

If required to treat at the proposed level,

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38939

treatment costs to non-community nontransient systems would be $15 million

per year. National annual costs for the

MCL options considered (3, 5, 10, and

20 μg/L) are provided in Table IX–11.

TABLE IX–11.—NATIONAL ANNUAL TREATMENT COSTS

[Dollars in millions]

MCL option

(μg/L)

Community

water systems

Non-community Non-transient systems

Total treatment costs

3 ................................................................................................................................................... $639 $25 $664

5 ................................................................................................................................................... 374 15 389

10 ................................................................................................................................................. 160 6 166

20 ................................................................................................................................................. 59 2 61

Total annual costs per household are

given in Table IX–12. Due to economies

of scale, costs per household are higher

in the smaller size categories, and lower

in the larger size categories. For the

proposed option of 0.005 μg/L, costs are

expected to be $364 per household for

systems serving 25–100 people, and

$254 per household for systems serving

101–500 people. Costs per households

in systems larger than those are

substantially lower: from $104 to $21

per household. Costs per household do

not vary dramatically across MCL

options. This is because of the fact that

once a system installs a treatment

technology to meet an MCL target, costs

do not vary significantly based upon the

removal efficiency it will be operated

under. Costs are, however, somewhat

lower at less stringent MCL options.

This is because it was assumed that

some systems would blend water at

these options, and treat only a portion

of the flow.

TABLE IX–12.—TOTAL ANNUAL COSTS PER HOUSEHOLD

[Dollars]

System size 3 μg/L 5 μg/L 10 μg/L 20 μg/L

25–100 ............................................................................................................. $368 $364 $357 $349

101–500 ........................................................................................................... 259 254 246 238

501–1K ............................................................................................................. 106 104 98 93

1K–3.3K ........................................................................................................... 64 60 57 52

3.3K–10K ......................................................................................................... 44 41 37 33

10K–50K .......................................................................................................... 36 33 29 25

50K–100K ........................................................................................................ 30 27 23 19

100K–1M .......................................................................................................... 23 21 18 15

Incremental costs are given in Tables

IX–13 and IX–14. Incremental costs

refer to the dollars that must be spent to

obtain the next, more stringent, level of

control. The national and household

costs under 20 μg/L refer to the amount

that must be spent to reach 20 μg/L

starting from the baseline of 50 μg/L.

The dollar value under 10 μg/L

represents the cost differential between

20 μg/L and 10 μg/L. The values under

5 μg/L and 3 μg/L were derived

similarly.

TABLE IX–13.—INCREMENTAL NATIONAL ANNUAL COSTS

[Dollars in millions]

MCL option

(μg/L)

Community

water systems

Non-community non-transient water

systems

Total

20 ................................................................................................................................................. $59 $2 $61

10 ................................................................................................................................................. 101 4 105

5 ................................................................................................................................................... 214 9 223

3 ................................................................................................................................................... 265 19 275

TABLE IX–14.—INCREMENTAL ANNUAL COSTS PER HOUSEHOLD

[Dollars]

System size 20 μg/L 10 μg/L 5 μg/L 3 μg/L

25–100 ............................................................................................................. $349 $8 $7 $4

101–500 ........................................................................................................... 238 8 8 5

501–1K ............................................................................................................. 93 5 6 2

1K–3.3K ........................................................................................................... 52 5 3 4

3.3K–10K ......................................................................................................... 33 4 4 3

38940 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

TABLE IX–14.—INCREMENTAL ANNUAL COSTS PER HOUSEHOLD—Continued

[Dollars]

System size 20 μg/L 10 μg/L 5 μg/L 3 μg/L

10K–50K .......................................................................................................... 25 4 4 3

50K–100K ........................................................................................................ 19 4 4 3

100K–1M .......................................................................................................... 15 3 3 2

In the process of analyzing treatment

technologies and developing cost

estimates, EPA held several meetings

with stakeholders to obtain input on

assumptions made. Several of the key

assumptions agreed to by stakeholders

are given below.

1. Assumptions Affecting the

Development of the Decision Tree

• EPA assumed that ion exchange

usage would be prohibited above 120

mg/L of sulfate and 500 mg/L of TDS.

• EPA assumed that greensand

filtration would be used only if iron in

the raw water was above 300 μg/L.

• EPA assumed that systems would

pre-oxidize, when existing chlorination

or other oxidants are not already

present.

• EPA assumed that systems would

not likely use POE–RO nor POE–IX

because of corrosion control problems.

Also, with IX, if the resin is not replaced

and/or regenerated on time, there is a

potential for arsenic peaking. EPA

assumed that systems will most likely

use POE–AA.

• The breakthrough issue also exists

with POU–IX. POU–AA has the

advantage of a longer run length. EPA

assumed that systems would use either

POU–AA or POU–RO.

2. Assumptions Affecting Unit Cost

Curves

• There are significant safety and

operating efficiency risks to small

systems when adjusting downward.

This pH adjustment would require

much more oversight than most small

systems will have. EPA, in calculating

unit costs for activate alumina assumed

that systems would not adjust pH

downward; thus, AA will be operated at

a sub-optimal pH.

• There is a danger of operating

technologies such as ion exchange near

breakthrough. EPA incorporated a safety

factor, and used 80% of the MCL as the

target when calculating costs for all

technologies.

• EPA assumed that small systems

would not regenerate Activated

Alumina on site—AA will likely be

operated on a ‘‘throw-away’’ basis.

• For modifying coagulation/

filtration, EPA considered the cost of a

new chemical feed system when

switching to iron. EPA costed out

switching coagulants for high removals.

For lower removals, EPA costed out

optimizing alum usage.

• EPA assumed 75% for RO recovery.

• For Activated Alumina, EPA

assumed that there will not be any

systems with raw water in the optimal

range for arsenic removal (pH between

5.5–6.0).

• For iron-coagulation-microfiltration EPA assumed systems would

apply a stronger iron dose rather than

adjusting to optimum pH.

• For ion exchange, one or more

regenerations per day is not

problematic. Regeneration in Ion

Exchange can be done automatically.

EPA examined cost models on

regeneration frequency, volume of waste

generated and considered computerautomation for regeneration.

X. Benefits of Arsenic Reduction

The benefits associated with

reductions of arsenic in drinking water

arise from a reduction in the risk of

adverse human health effects, and a

corresponding decrease in the number

of expected cases and premature deaths

of people experiencing these effects.

The various adverse health effects

associated with arsenic are known with

different levels of certainty. Presently

some can be quantified and some

cannot. The best characterized benefits

can be both quantified and monetized

(i.e., a dollar value is attached to the

expected decrease in number of cases),

while other benefits may be only known

well enough to describe. The latter are

known as qualitative benefits. The Safe

Drinking Water Act (SDWA)

amendments of 1996 require that EPA

fully consider both quantifiable and

non-quantifiable benefits that result

from drinking water regulations.

The first step in the benefits

evaluation process is to consider the

adverse health effects that may be

expected to decrease with a reduction in

the concentrations of arsenic in drinking

water. Arsenic has many health effects,

both cancer and non-cancer. Section III.

discusses these health effects.

As discussed in section VIII.A.,

treatment for arsenic removal may add

or remove other contaminants. Using

chlorine or other oxidants may increase

risk from disinfection by-products. On

the other hand, treatments put in place

for arsenic may incidentally reduce the

risk from other co-occurring

contaminants.

A. Monetized Benefits of Avoiding

Bladder Cancer

Reducing arsenic levels in tap water

will reduce the risks of suffering the

adverse health effects described in the

previous sections. In 1999 the National

Research Council examined several risk

distributions for male bladder cancer in

42 villages in Taiwan with arsenic

ranging from 10 to 934 μg/L, grouping

arsenic exposure by village. Previous

scientific studies analyzed risk using

less specific exposure categories, which

can obscure ‘‘the true shape of the dose

response curve (NRC 1999, page 273).’’

Risk assessments for other adverse

health effects have not been as

thoroughly addressed.

To monetize bladder cancer benefits,

EPA calculated the number of cases

potentially avoided based on the NRC

bladder cancer risk analyses. The cases

are evaluated in terms of the economic

benefits associated with avoiding the

cancer cases.

In addition to the monetized benefits

of avoiding bladder cancer, EPA has

chosen to monetize the potential

benefits of avoided lung cancer, using a

‘‘What If’’ analysis based on statements

in the NRC report (see section X.B for

applying the ‘‘what-if’’ scenario to lung

cancer).

1. Risk Reductions: The Analytic

Approach

EPA applied the 1999 NRC bladder

cancer risk assessment to U.S. males

and females. The following sections

explain how we calculated risk

reductions for populations exposed to

MCL options of 3 μg/L and above. The

approach for this analysis included five

components. First, EPA used data from

the recent EPA water consumption

study. This study is described in section

X.A.2. Second, Monte Carlo simulations

(section X.A.3) were used to develop

relative exposure factors (section X.A.4).

Third, arsenic occurrence estimates

were used to identify the population

exposed to levels above 3 μg/L. Fourth,

NRC risk distributions were chosen for

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38941

the analysis. Fifth, EPA developed

estimates of the risks faced by exposed

populations using Monte Carlo

simulations, using the relative exposure

factors, occurrence, and NRC risk

distributions mentioned above. These

components of the analysis are

described in the following sections.

2. Water Consumption

EPA recently updated its estimates of

personal (per capita) daily average

estimates of water consumption

(‘‘Estimated per Capita Water

Consumption in the United States,’’

EPA 2000a). The estimates used data

from the combined 1994, 1995, and

1996 Continuing Survey of Food Intakes

by Individuals (CSFII), conducted by the

U.S. Department of Agriculture (USDA).

The CSFII is a complex, multistage area

probability sample of the entire U.S. and

is conducted to survey the food and

beverage intake of the U.S. Estimates of

water consumed include direct water,

indirect water and total water (Table X–

1). ‘‘Direct’’ water is tap water

consumed directly as a beverage.

‘‘Indirect’’ water is defined as water

added to foods and beverages during

final preparation at home or by food

service establishments such as school

cafeterias and restaurants. For the

purpose of the report, indirect water did

not include ‘‘intrinsic’’ water which

consists of water found naturally in

foods (biological water) and water

added by commercial food and beverage

manufactures (commercial water).

‘‘Total’’ water refers to combined direct

and indirect water consumption.

TABLE X–1.—SOURCE OF WATER CONSUMED

Source Direct

(drinking)

Indirect (from

food and

beverages)

Bottled water

Community Tap ........................................................................................................................... X X

Well Tap ....................................................................................................................................... X X

Total ............................................................................................................................................. X X X

Per capita water consumption

estimates are reported by source.

Sources include community/tap water,

bottled water, and water from other

sources, including water from

household wells and rain cisterns, and

household and public springs. For each

source, the mean and percentiles of the

distribution of average daily per capita

consumption are reported. The

estimates are based on an average of 2

days of reported consumption by survey

respondents.

The estimated mean daily average per

capita consumption of community/tap

water by individuals in the U.S.

population is 1 liter/person/day. For

total water, which includes bottled

water, the estimated mean daily average

per capita consumption is 1.2 liters per/

person/day. These estimates of water

consumption are based on a sample of

15,303 individuals in the 50 States and

the District of Columbia. The sample

was selected to represent the entire

population of the U.S. based on 1990

census data.

The estimated 90th percentile of the

empirical distribution of daily average

per capita consumption of community/

tap water for the U.S. population is 2.1

liters/person/day; the corresponding

number for daily average per capita

consumption of total water is 2.3 liters/

person/day. In other words, current

consumption data indicate that 90

percent of the U.S. population

consumes up to approximately 2 liters/

person/day, which is the amount many

federal agencies use as a standard

consumption value.

Water consumption estimates for

selected subpopulations in the U.S. are

described in the analysis, including per

capita water consumption by source for

gender, region, age categories, economic

status, race, and residential status and

separately for pregnant women,

lactating women, and women in

childbearing years. The water

consumption estimates by age were

used in the computation of the relative

exposure factors discussed in the

section X.A.4.

These water consumption numbers

differ somewhat from previous

estimates reported in earlier studies.

The mean per capita daily intake of total

tap water, as estimated from the 1977–

78 USDA’s Nationwide Food

Consumption Survey, was 1.193 liters/

person/day (reported by Ershow and

Cantor in 1989). Based on the 1977–78

study, the estimated percentile

corresponding to 2 liters per day

consumed is the 88th.

3. Monte Carlo Analysis

Monte Carlo analysis is a technique

for analyzing problems where there are

a large number of combinations of input

values that are too large to calculate for

every possible result. A random number

generator is used to generate numbers

that correspond to assumptions about

the distribution or likelihood of various

input values. For each set of random

input values a single outcome is

calculated. As the simulation runs, the

outcome is recalculated for each new set

of input values and continues until a

stopping criterion is reached. The

accuracy of this technique, like other

statistical techniques, depends on the

accuracy of the underlying assumptions

about the distribution of input values; it

does not resolve the uncertainty behind

the assumptions. For the risk

distributions calculated in this report,

the simulations were carried out 2,000

times. For each simulation, a relative

exposure factor, occurrence estimate,

and individual risk estimate were

calculated. These calculations resulted

in estimates of the risks faced by

populations exposed to arsenic

concentrations in their drinking water.

The underlying risk distribution are

described in the following sections.

4. Relative Exposure Factors

EPA used models to integrate the new

drinking water consumption study

information into the benefits analysis.

We used distributions for both

community/tap water and total water

consumption because the community

water/tap water estimates may

underestimate actual tap water

consumption. In this analysis, we

combined the water consumption data

with data on population weight from the

U.S. Census. The weight data included

a mean and a distribution of weight for

male and females on a year-to-year basis

throughout a lifetime. Monte Carlo

analysis generated male and female

relative exposure factors (REFs) for each

of the broad age categories used in the

water consumption study. Lifetime male

and female relative exposure factors

were then estimated, where the factors

show the sensitivity of exposure to an

individual weighing 70 kilograms and

consuming 2 liters of water per day.

These life-long REFs can be directly

multiplied by the average drinking

water consumption to provide estimates

of individual lifetime consumption

38942 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

practices. The REFs provide a means to

incorporate information on various age

groups, for example children, into the

analysis, as weight and water

consumption vary among age groups.

The means and variances of the REFs

derived from this analysis were: for

community water consumption (0.60,

0.37 males; 0.64, 0.36 females), for total

water consumption (0.73, 0.39 males;

0.79, 0.37 females).

5. NRC Risk Distributions

While the NRC’s work did not

constitute a formal risk analysis, they

did examine many statistical issues

(e.g., measurement errors, age-specific

probabilities, body weight, water

consumption rate, comparison

populations, mortality rates, choice of

model) and provided a starting point for

additional EPA analyses. The report

noted that ‘‘poor nutrition, low

selenium concentrations in Taiwan,

genetic and cultural characteristics, and

arsenic intake from food’’ were not

accounted for in their analysis (NRC,

1999, pg. 295).

In its 1999 report, ‘‘Arsenic in

Drinking Water,’’ the NRC analyzed

bladder cancer risks using data from

Taiwan. In addition, NRC examined

evidence from human epidemiological

studies in Chile and Argentina, and

concluded that risks of bladder and lung

cancer were comparable to those ‘‘in

Taiwan at comparable levels of

exposure (NRC 1999, page 7).’’ The NRC

also examined the implications of

applying different mathematical

procedures to the newly available

Taiwanese data for the purpose of

characterizing bladder cancer risk.

These risk distributions are based on

bladder cancer mortality data in

Taiwan, in a section of Taiwan where

arsenic concentrations in the water are

very high by comparison to those in the

U.S. It is also an area of very low

incomes and poor diets, and the

availability and quality of medical care

is not of high quality, by U.S. standards.

In its estimate of bladder cancer risk, the

Agency assumed that within the

Taiwanese study area, the risk of

contracting bladder cancer was

relatively close to the risk of dying from

bladder cancer (that is, that the bladder

cancer incidence rate was equal to the

bladder cancer mortality rate). At the

time the study data were collected the

chances of surviving were probably poor

for individuals diagnosed with bladder

cancer. We do not have data, however,

on the rates of survival for bladder

cancer in the Taiwanese villages in the

study and at the time of data collection.

We do know that the relative survival

rates for bladder cancer in developing

countries overall ranged from 23.5% to

66.1% in 1982–1992 (‘‘Cancer Survival

in Developing Countries,’’ International

Agency for Research on Cancer, World

Health Organization, Publication No.

145, 1998). We also have some

information on annual bladder cancer

mortality and incidence for the general

population of Taiwan in 1996. The ageadjusted annual incidence rates of

bladder cancer for males and females,

respectively, were 7.36 and 3.09 per

100,000, with corresponding annual

mortality rates of 3.21 and 1.44 per

100,000 (correspondence from Chen to

Herman Gibb, January 3, 2000).

Assuming that the proportion of

males and females in the population is

equal, these numbers imply that the

mortality rate for bladder cancer in the

general population of Taiwan, at

present, is 45%. Since survival rates

have most likely improved over the

years since the original Taiwanese

study, this number represents a lower

bound on the survival rate for the

original area under study (that is, one

would not expect a higher rate of

survival in that area at that time). This

has implications for the bladder cancer

risk estimates from the Taiwan data. For

this estimate we have made the

assumption that all bladder tumors in

the study area in Taiwan were fatal. If

there were any persons with bladder

cancer who recovered and died from

some other cause, then our estimate

underestimated risk; that is, there were

more cancer cases than cancer deaths.

Based on the above discussion, we think

bladder cancer incidence could be no

more than 2 fold bladder cancer

mortality; and that an 80% mortality

rate would be plausible. In the benefits

analysis we include estimates using an

assumed mortality rate ranging from

80% to 100%.

In the U.S. approximately one out of

four individuals who is diagnosed with

bladder cancer actually dies from

bladder cancer. The mortality rate for

the U.S. is taken from a cost of illness

study recently completed by EPA (US

EPA, 1999a). For those diagnosed with

bladder cancer at the average age of

diagnosis (70 years), the probability for

dying of that disease during each year

post-diagnosis were summed over a 20-

year period to obtain the value of 26

percent. Mortality rates for U.S. bladder

cancer patients have decreased overall

by 24 percent from 1973 to 1996.

In the NRC report, Table 10–11 shows

excess risk estimates based on the

Taiwanese male bladder cancer, using a

Poisson regression model; a risk at the

current MCL of 50 μg/L is in the range

of 1 to 1.347 per 1,000. Table 10–12

presents excess lifetime risk estimates

for bladder cancer in males calculated

using EPA’s 1996 proposed revisions to

the cancer guidelines (US EPA 1996b).

EPA selected four of these distributions

as representative of the risks and

uncertainty involved (selecting

relatively high and relatively low

estimates). These distributions (mean

1.049, 95% upper confidence limit

1.347; mean 0.731, 95% upper

confidence limit 0.807; mean 1.237,

95% upper confidence limit 1.548; and

mean 1.129, 95% upper confidence

limit 1.229), were used in the EPA

Monte Carlo simulations. All of these

risk distributions are linear in the mean,

and thus may be conservative

assumptions, as the NRC report

suggested the true relationship may be

sublinear. If the true relationship is

sublinear, i.e., lower than the straight

line from 50 μg/L to zero, the true risks

at levels below 50 μg/L are being

overestimated. Other factors which

might lower the true risk include the

use of grouped data, the high Taiwanese

dietary intake of arsenic, and the

amount of selenium in the Taiwanese

diet.

NRC concluded that the present MCL

in drinking water of 50 μg/L does not

achieve EPA’s goal for public health and

requires downward revision. EPA did

not request nor did NRC recommend a

specific new MCL level.

6. Estimated Risk Reductions

Estimated risk reductions for bladder

cancer at various MCL levels were

developed using Monte Carlo

simulations. The inputs to the

simulations were the distributions of

relative risk factors (described in section

X.A.4.), distributions of occurrence for

arsenic levels at 3 μg/L and above, and

bladder cancer risk distributions from

the National Research Council report.

The relative risk factor and occurrence

distributions represent primarily

population and occurrence variability,

while the cancer risk distributions

represent primarily uncertainty about

the true risk. Thus the combined

distributions reflect both variability and

uncertainty. These combined

distributions provide our best estimate

of the actual risks faced by the exposed

population, including the percentiles of

the population facing various levels of

risk.

Estimated risk reductions for bladder

cancer at various MCL levels are shown

in Tables X–2a and X–2b. Table X–2a

uses data on community water

consumption from the new EPA study;

Table X–2b uses data on total water

consumption from the study.

Populations at or above 10 ¥4 risk levels

are shown in Tables X–3a and X–3b.

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38943

The after treatment occurrence

distributions were assumed to reflect

treatment to 80% of the MCL level. The

latter assumption is made since water

systems tend to treat below the MCL

level in order to provide a margin of

safety.

As shown in Table X–2a, bladder

cancer risks at the 90th percentile of

water intake, for the various MCL

options under consideration, range from

a multiple of 10¥5 at 3 μg/L (4–6 ×

10¥5) to a multiple of 10¥4 at 20 μg/L

(1.2–2.4 × 10¥4). At 5 μg/L , the 90th

percentile level is 6–11 × 10¥5; at 10 μg/

L the 90th percentile is 1.0–1.7 × 10¥4.

Table X–2b presents similar

information. The risk estimates in Table

X–2b are somewhat higher than those in

Table X–2a because total water

consumption is higher than community

water consumption. Since there is

uncertainty about these numbers, it is

assumed that the range 1–1.5 × 10¥4

represents a risk level of essentially

10¥4. It is then assumed that risks above

1.5 × 10¥4 represent risks greater than

10¥4. Table X–3a gives information

about percentages of the exposed

populations and the number of people

exposed at 10¥4 risk levels and above,

and, using the stated definition for an

over 10¥4 risk level, above 10¥4. The

numbers in this table show that at an

MCL of 3 μg/L, only a small number (not

quantifiable) face a risk level of greater

than 10¥4. At an MCL of 5 μg/L, about

0.3 to 0.8 million face such risk levels,

at an MCL of 10 μg/L, 0.8 to 4 million,

and at an MCL of 20 μg/L, about 2.4 to

6.4 million would be at such levels.

Table X–3b gives similar information

using total water consumption data. The

mean bladder cancer risks for the

exposed population at the various MCL

options, after treatment, are shown in

Tables X–4a and X–4b. These mean

risks are used in the computation of the

number of cases avoided, used later in

the benefits evaluation section.

TABLE X–2A.—BLADDER CANCER INCIDENCE RISKS 1 FOR HIGH PERCENTILE U.S. POPULATIONS EXPOSED AT OR ABOVE

MCL OPTIONS, AFTER TREATMENT 2 (COMMUNITY WATER CONSUMPTION DATA 3)

MCL (μg/L) 85th 90th 95th

3 ............................................................................................................... 3.2–5.4 × 10¥5 4–6 × 10¥5 4.3–7.5 × 10¥5

5 ............................................................................................................... 5.3–9.3 × 10¥5 6–11 × 10¥5 7.5–13.0 × 10¥5

10 ............................................................................................................. .88–1.49 × 10¥4 1.0–1.7 × 10¥4 1.26–2.12 × 10¥4

20 ............................................................................................................. 1.2–1.96 × 10¥4 1.4—2.4 × 10¥4 1.9–3.2 × 10¥4

1See Sections III.C. and D. for a description of other health effects, and Section X.B. for ‘‘What-if?’’ estimates of magnitude for lung cancer

risks. 2The bladder cancer risks presented in this table provide our ‘‘best’’ estimates at this time. Actual risks could be lower, given the various uncertainties discussed, or higher, as these estimates assume a 100% mortality rate. An 80% mortality rate is used in the computation of upper

bound benefits. 3 Discussed in Section X.A.2.

TABLE X–2B.—BLADDER CANCER INCIDENCE RISKS 1 FOR HIGH PERCENTILE U.S. POPULATIONS EXPOSED AT OR ABOVE

MCL OPTIONS, AFTER TREATMENT 2 (TOTAL WATER CONSUMPTION DATA 3)

MCL (μg/L) 85th 90th 95th

3 ............................................................................................................... 3.8–6.4 × 10¥5 4–7 × 10¥5 5–8.7 × 10¥5

5 ............................................................................................................... 6.3–10.5 × 10¥5 7–12 × 10¥5 8.5–14.5 × 10¥5

10 ............................................................................................................. 1.02–1.8 × 10¥4 1.2–2.0 × 10¥4 1.39–2.56 × 10¥4

20 ............................................................................................................. 1.4–2.34 × 10¥4 1.7–2.8 × 10¥4 2.17–3.56 × 10¥4

1See Sections III.C. and D. for a description of other health effects, and Section X.B. for ‘‘What-if?’’ estimates of magnitude for lung cancer

risks. 2The bladder cancer risks presented in this table provide our ‘‘best’’ estimates at this time. Actual risks could be lower, given the various uncertainties discussed, or higher, as these estimates assume a 100% mortality rate. An 80% mortality rate is used in the computation of upper

bound benefits. 3 Discussed in Section X.A.2.

TABLE X–3A.—PERCENT OF EXPOSED POPULATION AT 10¥4 RISK OR HIGHER FOR BLADDER CANCER INCIDENCE 1 AFTER

TREATMENT 2 (COMMUNITY WATER CONSUMPTION DATA 3)

MCL (μg/L)

Percent at

10¥4 risk or

higher

Population at

10¥4 risk or

higher (millions)

Percent over

10¥4 *

Population

over 10¥4

(millions)

3 ....................................................................................................................... <1–2.6 <0.3–0.7 <1 ‡

5 ....................................................................................................................... 1.5–12 0.4–3.2 <1–3 <0.3–0.8

10 ..................................................................................................................... 11–34 2.9–9.1 3–15 0.8–4

20 ..................................................................................................................... 19.5–41 5.2–11 9–24 2.4–6.4

1See Sections III.C. and D. for a description of other health effects, and Section X.B. for ‘‘What-if?’’ estimates of magnitude for lung cancer

risks. 2The percents presented in this table provide our ‘‘best’’ estimates at this time. Actual percents could be lower, given the various uncertainties

discussed, or higher, as these estimates assume a 100% mortality rate. An 80% mortality rate is used in the computation of upper bound benefits.3 Discussed in Section X.A.2.

* Where over 10¥4 means 1.5 × 10¥4 or above.

‡ Too low to calculate.

38944 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

1 If ‘‘X’’ is the probability of contracting bladder

cancer, then 0.26X is the probability of mortality

from bladder cancer. If lung cancer deaths are 2 to

5 times as high as bladder cancer, then they are, on

average, 3.5 times as high and the average

probability of mortality from lung cancer would be

3.5 times 0.26X, or 0.91X. Since we also know that

there is a 88% mortality rate from lung cancer, then

if the probability of contracting lung cancer is ‘‘Y,’’

the probability of mortality from lung cancer can

also be represented as 0.88Y. Setting the two ways

of deriving the probability of mortality from lung

cancer equal, or 0.91X = 0.88Y, one can solve for

Y (Y= (0.91/0.88) X). Thus Y is approximately equal

to X, and the rate of contracting lung cancer is

approximately the same as the rate of contracting

bladder cancer.

TABLE X–3B.—PERCENT OF EXPOSED POPULATION AT 10¥4 RISK OR HIGHER FOR BLADDER CANCER INCIDENCE 1 AFTER

TREATMENT 2 (TOTAL WATER CONSUMPTION DATA 3)

MCL (μg/L)

Percent at

10¥4 risk or

higher

Population at

10¥4 risk or

higher (millions)

Percent over

10¥4 *

Population

over 10¥4

(millions)

3 ....................................................................................................................... <1–3 <0.3–0.8 <1 ‡

5 ....................................................................................................................... 3–18 0.8–4.8 <1–4 0.3–1.1

10 ..................................................................................................................... 16–50 4.3–13.4 4–23 1.1–6.2

20 ..................................................................................................................... 26–53 7–14.2 13–33 3.5–8.9

1See Sections III.C. and D. for a description of other health effects, and Section X.B. for ‘‘What-if?’’ estimates of magnitude for lung cancer

risks. 2The percents presented in this table provide our ‘‘best’’ estimates at this time. Actual percents could be lower, given the various uncertainties

discussed, or higher, as these estimates assume a 100% mortality rate. An 80% mortality rate is used in the computation of upper bound benefits.3 Discussed in Section X.A.2.

* Where over 10¥4 means 1.5 × 10¥4 or above.

‡ Too low to calculate.

TABLE X–4A.—MEAN BLADDER CANCER INCIDENCE RISKS 1 FOR U.S.

POPULATIONS EXPOSED AT OR

ABOVE MCL OPTIONS, AFTER

TREATMENT 2 (COMMUNITY WATER

CONSUMPTION DATA 3)

MCL

(μ/L)

Mean exposed population risk

3 ................................ 2.1–3.6 × 10¥5

5 ................................ 3.6–6.1 × 10¥5

10 .............................. 5.5–9.2 × 10¥5

20 .............................. 6.9–11.6 × 10¥5

1See Sections III.C. and D. for a description

of other health effects, and Section X.B. for

‘‘What-if?’’ estimates of magnitude for lung

cancer risks. 2The bladder cancer risks presented in this

table provide our ‘‘best’’ estimates at this time.

Actual risks could be lower, given the various

uncertainties discussed, or higher, as these

estimates assume a 100% mortality rate. An

80% mortality rate is used in the computation

of upper bound benefits. 3 Discussed in Section X.A.2.

TABLE X–4B.—MEAN BLADDER CANCER INCIDENCE RISKS 1 FOR U.S.

POPULATIONS EXPOSED AT OR

ABOVE MCL OPTIONS, AFTER

TREATMENT 2 (TOTAL WATER CONSUMPTION DATA 3)

MCL

(μ/L)

Mean exposed population risk

3 ................................ 2.6–4.5 × 10¥5

5 ................................ 4.4–7.5 × 10¥5

10 .............................. 6.7–11.4 × 10¥5

20 .............................. 8.4–13.9 × 10¥5

1See Sections III.C. and D. for a description

of other health effects, and Section X.B. for

‘‘What-if?’’ estimates of magnitude for lung

cancer risks. 2The bladder cancer risks presented in this

table provide our ‘‘best’’ estimates at this time.

Actual risks could be lower, given the various

uncertainties discussed, or higher, as these

estimates assume a 100% mortality rate. An

80% mortality rate is used in the computation

of upper bound benefits. 3 Discussed in Section X.A.2.

B. ‘‘What if?’’ Scenario for Lung Cancer

Risks

The NRC report ‘‘Arsenic in Drinking

Water’’ states that ‘‘some studies have

shown that excess lung cancer deaths

attributed to arsenic are 2–5 fold greater

than the excess bladder cancer deaths

(NRC, 1999, pg. 8).’’ Two-to-five fold

greater would be 3.5 fold greater on

average. Also in the U.S. the mortality

rate from bladder cancer is 26% and the

mortality rate of lung cancer is 88%.

This suggests that if the risk of

contracting lung cancer were identical

to the risk of contracting bladder cancer,

one would expect 3.4 times the number

of deaths from lung cancer as from

bladder cancer. Since these numbers are

essentially the same, it seems reasonable

to assume that the risk of contracting

lung cancer is essentially the same as

the rate of contracting bladder cancer,1

in the context of this ‘‘what-if’’ scenario.

If the risk of contracting lung cancer

from arsenic in drinking water is

approximately equal to the risk of

contracting bladder cancer, then the

combined risk estimates of contracting

either bladder or lung cancer would be

approximately double the risk estimates

presented in the previous tables.

EPA anticipates that a peer-reviewed

quantification of lung cancer risk from

arsenic exposure may be available

between the time of proposal and

promulgation. If so, EPA will make this

information available for public

comment through a Notice of Data

Availability (NODA) and consider the

analysis and public comment for the

final rulemaking.

C. Evaluation of Benefits

The evaluation stage in the analysis of

risk reductions involves estimating the

value of reducing the risks. Background

information on the economic concepts

that provide the foundation for benefits

valuation, and the methods that are

typically used by economists to

monetize the value of risk reductions,

such as wage-risk, cost of illness, and

contingent valuation studies are

provided in the RIA. The following

sections describe the use of these

techniques to estimate the value of the

risk reductions attributable to the

regulatory options for arsenic in

drinking water. Described first is the

approach for valuing the reductions in

fatal risks; described next is the

approach for valuing the reductions in

nonfatal risks.

The benefits calculated for this

proposal are assumed to begin to accrue

on the effective date of the rule and are

based on a calculation referred to as the

‘‘value of a statistical life’’ (VSL),

currently estimated at $5.8 million. The

VSL is an average estimate derived from

a set of 26 studies estimating what

people are willing to pay to avoid the

risk of premature mortality. Most of

these studies examine willingness to

pay in the context of voluntary

acceptance of higher risks of immediate

accidental death in the workplace in

exchange for higher wages. This value is

sensitive to differences in population

characteristics and perception of risks

being valued.

For the present rulemaking analysis,

which evaluates reduction in premature

mortality due to carcinogen exposure,

some have argued that the Agency

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38945

2Some of the key sources of bias include the

characteristics of the averted risks (whether they are

voluntary or involuntary, ordinary or catastrophic,

delayed or immediate, natural or man-made, etc.);

the demographic characteristics of the group

affected (e.g., age, income); the lag between

exposure and diagnosis or incidence of the disease

(latency) as well as between incidence and death;

the baseline health status (i.e., whether a person is

currently in good health) of affected individuals;

and the presence of altruism (i.e., individual’s

willingness to pay to reduce risks incurred by

others) (US EPA, 1997f).

should consider an assumed time lag or

latency period in these calculations.

Latency refers to the difference between

the time of initial exposure to

environmental carcinogens and the

onset of any resulting cancer. Use of

such an approach might reduce

significantly the present value estimate.

EPA is interested in receiving comments

on the extent to which the presentation

of more detailed information on the

timing of cancer risk reductions would

be useful in evaluating the benefits of

the proposed rule.

Latency is one of a number of

adjustments or factors that are related to

an evaluation of potential benefits

associated with this rule, how those

benefits are calculated, and when those

economic benefits occur. Other factors

which may influence the estimate of

economic benefits associated with

avoided cancer fatalities include (1) a

possible ‘‘cancer premium’’ (i.e., the

additional value or sum that people may

be willing to pay to avoid the

experiences of dread, pain and

suffering, and diminished quality of life

associated with cancer-related illness

and ultimate fatality); (2) the

willingness of people to pay more over

time to avoid mortality risk as their

income rises; (3) a possible premium for

accepting involuntary risks as opposed

to voluntary assumed risks; (4) the

greater risk aversion of the general

population compared to the workers in

the wage-risk valuation studies; (5)

‘‘altruism’’ or the willingness of people

to pay more to reduce risk in other

sectors of the population; and (6) a

consideration of health status and life

years remaining at the time of premature

mortality. Use of certain of these factors

may significantly increase the present

value estimate. EPA therefore believes

that adjustments should be considered

simultaneously. The Agency also

believes that there is currently neither a

clear consensus among economists

about how to simultaneously analyze

each of these adjustments nor is there

adequate empirical data to support

definitive quantitative estimates for all

potentially significant adjustment

factors. As a result, the primary

estimates of economic benefits

presented in the analysis of this

proposed rule rely on the unadjusted

estimate. However, EPA solicits

comment on whether and how to

conduct these potential adjustments to

economic benefits estimates together

with any rationale or supporting data

commenters wish to offer. Because of

the complexity of these issues, EPA will

ask the Science Advisory Board (SAB)

to conduct a review of these benefits

transfer issues associated with economic

valuation of adjustments in mortality

risks. Consistent with the

recommendations of the SAB, and

subject to resolution of any technical

problems, EPA will attempt to develop

and present an estimate of the latency

structure as a part of the analysis of the

final rule, with prior solicitation of

comment, if appropriate.

1. Fatal Risks and Value of a Statistical

Life (VSL)

To estimate the monetary value of

reduced fatal risks (i.e., risks of

premature death from cancer) predicted

under different regulatory options, value

of a statistical life (VSL) estimates are

multiplied by the number of premature

fatalities avoided. VSL does not refer to

the value of an identifiable life, but

instead to the value of small reductions

in mortality risks in a population. A

‘‘statistical’’ life is thus the sum of small

individual risk reductions across an

entire exposed population.

For example, if 100,000 people would

each experience a reduction of 1/

100,000 in their risk of premature death

as the result of a regulation, the

regulation can be said to ‘‘save’’ one

statistical life (i.e., 100,000 × 1/100,000).

If each member of the population of

100,000 were willing to pay $20 for the

stated risk reduction, the corresponding

value of a statistical life would be $2

million (i.e., $20 × 100,000). VSL

estimates are appropriate only for

valuing small changes in risk; they are

not values for saving a particular

individual’s life.

Of the many VSL studies, the Agency

recommends using estimates from 26

specific studies that have been peer

reviewed and extensively reviewed

within the Agency (US EPA, 1997f).

These estimates, which are derived from

wage-risk and contingent valuation

studies, range from $0.7 million to $16.3

million and approximate a Wiebull

distribution with a mean of $5.8 million

(in 1997 dollars). To value the changes

in fatal risks associated with the arsenic

regulation, the mean estimate of $5.8

million is used.

Use of these estimates to value the

averted risks of premature death

associated with the regulatory options

for arsenic is an example of the benefit

transfer technique, since the subject of

most of the studies (i.e., job-related

risks) differs from the fatal cancer risks

averted by the regulatory options.

Applying these studies results in several

sources of potential bias (see latency

discussion in section X.C.); however,

quantitative adjustments to address

these biases generally have not been

developed or adequately tested and may

be counterbalancing.2 EPA notes the

uncertainties in the cost-benefit

analyses, as required by section

1412(b)(3)(C)(i)(VII) of SDWA, and

requests comment on alternate

approaches.

2. Nonfatal Risks and Willingness To

Pay (WTP)

Estimates of the willingness to pay to

avoid treatable, nonfatal cancers are the

ideal economic measures used for

evaluation of the reduction in nonfatal

risks. However this information is not

available for bladder cancer.

Willingness to pay (WTP) data to avoid

chronic bronchitis is available, however,

and has been used before by EPA (the

microbial/disinfection by-product

(MDBP) rulemaking) as a surrogate to

estimate the WTP to avoid non-fatal

bladder cancer. The use of such WTP

estimates is supported in the SDWA, as

amended, at section 1412(b)(3)(C)(iii):

‘‘The Administrator may identify valid

approaches for the measurement and

valuation of benefits under this

subparagraph, including approaches to

identify consumer willingness to pay for

reductions in health risks from drinking

water contaminants.’’ The WTP central

tendency estimate of $536,000, to avoid

chronic bronchitis, is used to monetize

the benefits of avoiding non-fatal

bladder cancers (Viscusi et al., 1991).

EPA has also developed cost of illness

estimates for bladder cancer, as reported

in Table X–5. These estimates of direct

medical costs are derived from a study

conducted by Baker et al., (as cited in

US EPA, 1997f) which uses data from a

sample of Medicare records for 1974–

1981. These data include the total

charges for inpatient hospital stays,

skilled nursing facility stays, home

health agency charges, physician

services, and other outpatient and

medical services. EPA combined these

data with estimates of survival rates and

treatment time periods to determine the

average costs of initial treatment and

maintenance care for patients who do

not die of the disease.

38946 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

TABLE X–5.—LIFETIME AVOIDED MEDICAL COSTS FOR SURVIVORS (PRELIMINARY ESTIMATES, 1996 DOLLARS 1)

Type of cancer Date data

collected Number of cases studied Estimated survival rate Mean value per nonfatalcase 2

Bladder .................................... 1974–1981 5% of 1974 Medicare patients

(sample from national statistics).

26 percent (after 20 years) ..... $179,000 (for typical individual

diagnosed at age 70)

1These costs increase by 2.8 percent when inflated to 1997 dollars, based on the consumer price index for the costs of medical commodities

and services. 2 Undiscounted costs.

Source: US EPA, 1999a.

D. Estimates of Quantifiable Benefits of

Arsenic Reduction

Benefits estimates for avoided cases of

bladder cancer were calculated using

mean population risk estimates at

various MCL levels. Table X–6 gives the

mean populations risk estimates used,

which are a composite of the mean

population risk estimates discussed

earlier. Lifetime risk estimates were

converted to annual risk factors, and

applied to the exposed population to

determine the number of cases avoided.

These cases were divided into fatalities

and non-fatal cases avoided, based on

survival information. The avoided

premature fatalities were valued based

on the VSL estimates discussed earlier,

as recommended by EPA current

guidance for cost/benefit analysis. The

avoided non-fatal cases were valued

based on the willingness to pay

estimates for the avoidance of chronic

bronchitis. The upper bound estimates

have been adjusted upwards to reflect

an 80% mortality rate, which is a

plausible mortality rate for the area of

Taiwan during the Chen study.

The ‘‘What if?’’ scenario for lung

cancer benefits (described in section

X.B.) was used to estimate potential

benefits for avoided cases of lung

cancer. This scenario is based on the

statement in the NRC report ‘‘Arsenic in

Drinking Water’’ that ‘‘some studies

have shown that excess lung cancer

deaths attributed to arsenic are 2–5 fold

greater than the excess bladder cancer

deaths (NRC, 1999, pg. 8).’’ It was

shown in section X.D that the statement

implies (if it were accurate for the U.S.),

that, because of the relative U.S.

mortality rates for bladder and lung

cancer, the rate of contracting lung

cancer could be essentially the same as

the rate of contracting bladder cancer.

This would double the number of

cancer cases avoided, for both low and

high estimates. The potential monetized

benefits for lung cancer would be

several times higher than those for

bladder cancer, due to the higher

number of fatalities involved with lung

cancer.

Another way of considering the

addition of lung cancer effects would be

to estimate the potential benefits from

avoided cases of lung cancer using the

2–5 times range for fatalities (that is,

taking the expected number of bladder

cancer fatalities and multiplying them

by 2 and then 5 to obtain a range of lung

cancer fatalities, and then factoring in

non-fatal cases).

Benefits (and costs) are assumed to

accrue on the effective date of the rule.

Table X–7 displays the results.

TABLE X–6.–MEAN BLADDER CANCER INCIDENCE RISKS 1 FOR U.S. POPULATIONS EXPOSED AT OR ABOVE MCL OPTIONS,

AFTER TREATMENT 2 (COMPOSITE OF TABLES X–5A AND X–5B)

MCL (μg/L) Mean exposed

population risk

3 ............................................................................................................................................................................................... 2.1¥4.5×10¥ 5

5 ............................................................................................................................................................................................... 3.6¥7.5×10¥ 5

10 ............................................................................................................................................................................................. 5.5¥11.4×10¥ 5

20 ............................................................................................................................................................................................. 6.9¥13.9×10¥ 5

1See Sections III.C. and D. for a description of other health effects, and Section X.B. for ‘‘What-if?’’ estimates of magnitude for cancer risks. 2The bladder cancer risks presented in this table provide our ‘‘best’’ estimates at this time. Actual risks could be lower, given the various uncertainties discussed, or higher, as these estimates assume a 100% mortality rate. An 80% mortality rate is used in the computation of upper

bound benefits.

TABLE X–7.—ESTIMATED COSTS AND BENEFITS FROM REDUCING ARSENIC IN DRINKING WATER

[Millions, 1999]

Arsenic level (μg/l)

Total national

costs to

CWSs 1

Total national

costs to CWSs

and

NTNCWSs 2

Total bladder

cancer health

benefits 3

‘‘What if’’ scenario 4 and potential non-quantified benefits

‘‘What If’’ lung

cancer health

benefits estimates

Potential non-quantifiable health benefits

3 ...................................... $643.1–753 $644.6–756.3 $43.6–104.2 5(79)$47.2–448 6(213.4)• Skin Cancer.

• Kidney Cancer.

• Cancer of the Nasal Passages.

5 ...................................... 377.3–441.8 378.9–444.9 31.7–89.9 5(64.3)35–384

6(173.4)

• Liver Cancer.

• Prostate Cancer.

10 .................................... 163.3–191.8 164.9–194.8 17.9–52.1 5(37)19.6–224 6(100)• Cardiovascular Effects.

• Pulmonary Effects.

• Immunological Effects.

• Neurological Effects.

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38947

TABLE X–7.—ESTIMATED COSTS AND BENEFITS FROM REDUCING ARSENIC IN DRINKING WATER—Continued

[Millions, 1999]

Arsenic level (μg/l)

Total national

costs to

CWSs 1

Total national

costs to CWSs

and

NTNCWSs 2

Total bladder

cancer health

benefits 3

‘‘What if’’ scenario 4 and potential non-quantified benefits

‘‘What If’’ lung

cancer health

benefits estimates

Potential non-quantifiable health benefits

20 .................................... 61.6–72.9 63.2–77.1 7.9–29.8 5(19.8)8.8–128

6(53.4)

• Endocrine Effects.

• Reproductive and Developmental Effects.

1 Costs include treatment, monitoring, O&M, and administrative costs to CWSs and State costs for administration of water programs. The lower

number shows costs annualized at a consumption rate of interest of 3%, EPA’s preferred approach. The higher number shows costs annualized

at 7%, which represents the standard discount rate preferred by OMB for benefit-cost analyses of government programs and regulations. 2 Costs include treatment, monitoring, O&M, administrative costs to CWSs; monitoring and administrative costs to NTNCWSs; and State costs

for administration of water programs. 3The upper bound estimate includes an adjustment to account for a possible mortality risk of 80%. It is possible that this risk could have been

below 80%, which would lead to increased benefits. The actual risk depends on the survival rate for bladder cancer in the area of Taiwan studied

by Chen, which is unknown. 4These estimates are based on the ‘‘what if’’ scenario for lung cancer, where the risks of a fatal lung cancer case associated with arsenic are

assumed to be 2–5 times that of a fatal bladder cancer case. 5The number in parentheses indicates the bladder cancer health benefits assuming an 80% mortality rate for bladder cancer in the area of the

Chen study, and starting from the midpoint of the benefits range when mortality and incidence are assumed equivalent. 6The number in parentheses is the midpoint of the range and corresponds to an assumption that the risk of fatal lung cancer is 3.5 times the

risk of fatal bladder cancer.

F. NDWAC Working Group (NDWAC,

1998) on Benefits

The National Drinking Water

Advisory Council (NDWAC)

recommends that:

(1) EPA should focus its benefits

analysis efforts primarily on assessing

effects on human health, defining these

effects as clearly as possible and using

the best available data to value them. It

is also recommended that EPA should

also consider, where appropriate, taste

and odor improvements, reduction of

damage to water system materials,

commercial water treatment cost

reductions, benefits due to source water

protection (e.g., ecological benefits and

non-use benefits), and benefits derived

from the provision of information on

drinking water quality (e.g., a

household’s improved ability to make

informed decisions concerning the need

to test or filter tap water);

(2) EPA should devote substantial

efforts to better understanding the

health effects of drinking water

contaminants, including the types of

effects, their severity, and affected

sensitive subpopulations. Better

information is also needed on exposures

and the effects of different exposure

levels, particularly for contaminants

with threshold effects. These efforts

should pay particular attention to

obtaining improved information

concerning impacts on children and

other sensitive populations;

(3) EPA should clearly identify and

describe the uncertainties in the benefits

analysis, including descriptions of

factors that may lead the analysis to

significantly understate or overstate

total benefits. Factors that may have

significant but indeterminate effects on

the benefits estimates should also be

described;

(4) EPA should consider both

quantified and non-quantified benefits

in regulatory decision-making. The

information about quantified and nonquantified (qualitative) benefits should

be presented together in a format, such

as a table, to ensure that decisionmakers consider both kinds of

information;

(5) EPA should consider incremental

benefits and costs, total benefits and

costs, the distribution of benefits and

costs, and cost-effectiveness in

regulatory decision-making. This

information should be presented

together in a format, such as a table, to

ensure its consideration by decisionmakers;

(6) Whenever EPA considers

regulation of a drinking water

contaminant, it should evaluate and

consider, along with water treatment

requirements to remove a contaminant,

source water protection options to

prevent such a contaminant from

occurring. The full range of benefits of

those options should be considered.

XI. Risk Management Decisions: MCL

and NTNCWSs

A. What Is the Proposed MCL?

EPA is proposing an arsenic MCL of

5 μg/L and soliciting comments on

options of 3μg/L, 10 μg/L, and 20 μg/L.

EPA is also asking that commenters

provide their rationale and any

supporting data or information for the

option they prefer.

The SDWA generally requires that

EPA set the MCL for each contaminant

as close as feasible to the MCLG, based

on available technology and taking costs

to large systems into account. The 1996

amendments to the SDWA added the

requirement that the Administrator

determine whether or not the

quantifiable and nonquantifiable

benefits of an MCL justify the

quantifiable and nonquantifiable costs

based on the Health Risk Reduction and

Cost Analysis (HRRCA) required under

section 1412(b)(3)(C). The 1996 SDWA

amendments also provided new

discretionary authority for the

Administrator to set an MCL less

stringent than the feasible level if the

benefits of an MCL set at the feasible

level would not justify the costs (section

1412(b)(6)). This proposal to establish

an MCL for arsenic of 5 μg/L is the first

time EPA has invoked this new

authority.

In conducting this analysis, EPA

considered all available scientific

information concerning the health

effects of arsenic, including various

uncertainties in the interpretation of the

results. As discussed in more detail

below, an array of health endpoints of

concern were considered in this

analysis. For some of these, the risk can

currently be quantified (i.e., expressed

in numerical terms); and for some, it

cannot. Similarly, there are a variety of

health and other benefits attributable to

reductions in levels of arsenic in

drinking water, some of which can be

monetized (i.e., expressed in monetary

terms) and others that cannot yet be

monetized. All were considered in this

analysis. The array of factors taken into

account in making risk management

decisions for arsenic underscore the

difficulty of recommending the most

appropriate regulatory level. A detailed

38948 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

discussion of each of the principal

factors considered follows.

1. Feasible MCL

Because arsenic is a carcinogen with

no established mode of action, EPA is

proposing that the MCLG be set at zero.

To establish the MCL, EPA must first

determine the level which is as close to

this level as feasible. EPA has

determined that 3 μg/L is

technologically feasible for large

systems based on peer-reviewed

treatment information and the practical

quantitation level achievable with

available analytical methods.

2. Principal Considerations in Analysis

of MCL Options

In addition to the feasible MCL of 3

μg/L, the Agency evaluated MCL

options of 5 μg/L, 10 μg/L, and 20 μg/

L. EPA considered the health effects

associated with arsenic, the risk levels

to the population for these health effects

that would remain after

implementation, and the costs and

benefits of the different options (both

those that could be monetized and/or

quantified now and those that could

not). The Agency’s assessment centered

on the health risk posed by arsenic in

drinking water as well as on the benefits

and costs imposed by the options

evaluated. These options were then

analyzed, taking into consideration the

uncertainties involved in each of these

factors. EPA solicits public comment on

all the factors it considered in making

this decision.

Estimates of risk levels to the

population remaining after the

regulation is in place provide a

perspective on the level of public health

protection and benefits. The SDWA

clearly places a particular focus on

public health protection afforded by

MCLs. For instance, where EPA decides

to use its discretionary authority after a

determination that the benefits of an

MCL would not justify the costs, section

1412(b)(6)(A) requires EPA to set the

MCL at a level that ‘‘maximizes health

risk reduction benefits at a cost that is

justified by the benefits.’’

The SDWA requires the Agency to

consider both quantifiable and

nonquantifiable health risk reduction

benefits (quantifiable benefits can

include both those that are monetizable

and those that are not). Nonmonetizable benefits range from those

about which some quantitative

information is known (such as skin

cancer), and those which are more

qualitative in nature (such as some of

the non-cancer health effects associated

with arsenic). If additional potential

benefits that are presently not

monetized (see Table XI–1) could be

estimated at some future point, the

benefits might increase further.

(Important assumptions inherent in

EPA’s benefits estimates, including the

value of a statistical life and willingness

to pay are discussed in section X.C.)

EPA considered the relationship of

the monetized benefits to the monetized

costs for each option. While equality of

monetized benefits and costs is not a

requirement under section

1412(b)(6)(A), this relationship is still a

useful tool in comparing costs and

benefits. However, EPA believes that

reliance on a simple arithmetic analysis

of whether monetized benefits outweigh

monetized costs is inconsistent with the

HRRCA’s instruction to consider both

quantifiable and non-quantifiable costs

and benefits. The Agency therefore

believes it is necessary to also examine

the qualitative and non-monetized

benefits and consider these benefits in

establishing the MCL.

3. Findings of NRC and Consideration of

Risk Levels

The Agency based its evaluation of

the risk posed by arsenic at the MCL

options of 3 μg/L, 5 μg/L, 10 μg/L and

20 μg/L on national and international

research, the bladder cancer risk

analysis provided by the National

Research Council (NRC) report issued

by the National Academy of Sciences

(NRC 1999), and the NRC’s qualitative

statements of overall risk of combined

cancers. The Agency is relying heavily

on the findings of the NRC for a number

of reasons. In carrying out its charge, the

NRC assembled an independent body of

preeminent scientists from several

disciplines. This committee examined

and carefully analyzed more

information than has been available

before, and NRC had the draft report

peer reviewed by thirteen other

individuals with ‘‘diverse perspectives

and technical expertise (NRC 1999b).’’

EPA decided, in 1996, to charge the

NRC with evaluating EPA’s two risk

assessments for arsenic and considering

the most current national and

international research on arsenic. The

NRC determined that the current MCL

of 50 μg/L is not adequately protective

and should be revised downward as

soon as possible. The NRC conducted a

number of statistical analyses in making

this determination. The report also

recommended that EPA conduct

separate analyses for ‘‘bladder, lung,

and other internal cancers,’’ as well as

consider the combined impact of these

various health effects.

Given the release date of the NRC

report (March 1999) relative to the

timing of the proposed rule and the

additional analyses needed to

definitively quantify all endpoints of

concern, EPA chose to use NRC’s

bladder cancer analysis to quantify and

monetize the bladder cancer risk for the

proposed rule. NRC provided

quantitative risk factors for bladder

cancer, that, when combined with key

risk characterization scenarios by EPA

and qualitative benefits, yield risks and

benefits associated with various

possible MCL options. The NRC report

also noted that lung cancer deaths due

to arsenic could be 2 to 5 times higher

than bladder cancer deaths, considering

the frequency and incidence of cancers

projected from international studies.

However, the report did not provide a

numeric risk-based quantification

analysis for this judgment similar to that

provided for bladder cancer. As noted in

section X.E., EPA approximated the

potential benefits of avoiding arsenicrelated lung cancer by assuming that the

probability of incidence of lung cancer

is approximately equal to that of bladder

cancer. One can then use the death rate

associated with lung cancer (88% for

lung cancer as compared to 26% for

bladder cancer) to derive benefits and to

consider the implications of this health

endpoint on risk. The risk factors

associated with various MCL options

increase under this ‘‘What If’’ analysis,

with 10 μg/L being on the upper end or

just outside of the Agency’s 1 × 10¥4

risk range and more stringent MCL

options being more solidly under this

risk ceiling.

EPA anticipates that a peer reviewed

quantification of lung cancer risk from

arsenic exposure may be available

between the time of proposal and

promulgation. If so, EPA will make this

information available for public

comment through a Notice of Data

Availability (NODA) and consider the

analysis and public comment for the

final rulemaking.

Individual risk varies widely

depending on susceptibility, amount of

drinking water consumption, dietary

levels of arsenic, years of exposure, and

other factors. Consequently, any single

MCL does not provide the same level of

protection to all individuals. While not

required by statute, the Agency has

historically set protectiveness levels

within a risk range of 10¥4 to 10¥6. EPA

has sought to ensure that drinking water

standards were established at levels

such that less than 10% of the exposed

population faced a risk that exceeded

the chosen risk level. This conclusion is

based on a recognition of its

responsibility to protect public health,

together with its obligation to consider

a range of risk management factors

when establishing regulatory levels.

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38949

4. Non-Monetized Health Effects

There are a number of important nonmonetized benefits that EPA considered

in its analysis. Chief among these are

certain health impacts known to be

caused by arsenic (such as skin cancer).

A number of epidemiologic studies

conducted in several countries (e.g.,

Taiwan, Japan, England, Hungary,

Mexico, Chile, and Argentina) report an

association between arsenic in drinking

water and skin cancer in exposed

populations. Studies conducted in the

U.S. have not demonstrated an

association between inorganic arsenic in

drinking water and skin cancer.

However, these studies may not have

included enough people in their design

to detect these types of effects.

There were also a large number of

other health effects associated with

arsenic, discussed in section III, and

listed in Table XI.1, which are not

monetized, due to lack of appropriate

quantitative data. These health effects

include other cancers such as prostate

cancer and cardiovascular, pulmonary,

neurological and other non-cancer

endpoints.

Other benefits not monetized for this

proposal include customer peace of

mind from knowing drinking water has

been treated for arsenic and reduced

treatment costs for currently

unregulated contaminants that may be

co-treated with arsenic. To the extent

that reverse osmosis is used for arsenic

removal, these benefits could be

substantial. Reverse osmosis is the

primary point of use treatment, and it is

expected that very small systems will

use this treatment to a significant extent.

5. Sources of Uncertainty

Among the non-quantifiable factors

EPA considered in choosing the

proposed MCL was Congress’ intent that

EPA ‘‘reduce * * * [scientific]

uncertainty’’ in promulgating the

arsenic regulation, reflected in the

1412(b)(12) arsenic research plan

provisions and the legislative history for

the arsenic provision (S. Rep. 104–169,

104th Cong., 1st Sess. at 39–40).

All assessments of risk are

characterized by an amount of

uncertainty. Some of this can be

reduced by collecting more data or data

of a different sort; for other types of

uncertainty, improved data or

assessment methods can allow one to

define the degree to which an estimate

is likely to be above or below the ‘‘true’’

risk. For the arsenic risk assessment,

there are some definable sources of

uncertainty. These include (but aren’t

limited to) the following: choice of

endpoint and population; uncertainty

about the exact exposure of individuals

in the study population; issues on

applying data from rural Taiwanese to

the heterogenous population of the U.S.;

the inability to know precisely how a

chemical causes cancer in humans (the

mode of action, which affects judgments

as to the shape of the chemical’s dose

response curve at low doses); choice of

mathematical modeling procedures.

Congress established a dual path for

arsenic in SDWA: on the one hand, EPA

is to issue a proposed MCL in 41⁄2 years;

on a parallel track EPA is to develop a

long-term research plan, complete the

required consultations and peer

reviews, complete the research, and

fully consider the research results.

While the plan has been developed and

research is underway, not all research

results will be available for the final

rule. However, EPA did obtain through

the NRC study the most authoritative

review of existing scientific information

available. This review examined the

areas of uncertainty listed above.

EPA considered uncertainty about

arsenic’s mode of action and the shape

of the dose response curve below the

observable range of data. EPA is

proposing an MCLG of zero. This

decision is supported by the NRC’s

findings that the dose-response

relationship at low doses is uncertain

and that a conservative, default

assumption of linearity is advisable. (An

assumption of linearity in the doseresponse relationship implies that there

is no ‘‘safe’’ level that can be identified

at which no health effects are expected

to occur.) However, the Agency also

notes the NRC’s conclusion that ‘‘* * *

a sublinear dose-response curve in the

low dose range is predicted, although

linearity cannot be ruled out.’’ (NRC,

1999, pg. 6). EPA believes the NRC

study’s articulation of uncertainty about

the shape of the dose-response curve

below the observed health effect range

is an important qualitative

consideration and, given Congress’

concern about scientific ‘‘uncertainty’’

in setting the arsenic level, guides EPA

to a default assumption of linearity.

The choice of one endpoint for risk

assessment is a judgment call. While

this choice is guided by the best

available science, it introduces

uncertainty. Basing the risk assessment

on incidence of bladder tumors will

underestimate the combined risk of all

arsenic-induced health effects. Section

XI.A.4. discusses how assessments of

other tumor types and health endpoints

would result in a higher estimate of

arsenic risk.

Another source of uncertainty is in

the application of data from one human

population to another. EPA believes that

the differences in dietary contributions

of arsenic that NRC identified in the

Taiwan study population and the U.S.

are important to consider and a source

of uncertainty in interpreting the

results. NRC estimated that daily

inorganic arsenic intake from food in

the U.S. ranges from 1.3 μg/day for

infants, to 4.5 μg/day for males 14–16

years old and 5.2 μg/day for females 14–

16 years old, to a maximum of 12.5 μg/

day for 60–65 year-old males and 9.7 μg/

day for 60–65 year old females. On the

other hand, NRC cited a study (Schoof

et al., 1998) that estimated the

Taiwanese obtain 31 μg/day of inorganic

arsenic from yams and 19 μg/day from

rice, ‘‘for a total of 50 μg/day within a

range of estimates of 15–211 μg/day

(NRC, 1999, pg. 51).’’ NRC noted (p. 24)

that ‘‘Limited data on dietary arsenic

intake in the blackfoot-disease region

now available suggest that arsenic

intake from food is higher in Taiwan

than in the United States.’’ NRC noted

that EPA previously observed that

arsenic intake from sources other than

drinking water would overestimate the

unit risk calculated from the Taiwan

study (US EPA 1988, pg. 86). The report

noted that improved quantification of

arsenic in Taiwanese food might affect

the risk assessment for arsenic in

drinking water in the U.S. (NRC 1999,

pg. 6).

In addition, the NRC report discussed

laboratory animal studies that indicated

that selenium reduced the toxicity of

arsenic. While there is no direct

evidence for humans, NRC noted that

‘‘Selenium status there [in Taiwan]

should be considered a moderator of

arsenic toxicity and taken into account

when the Taiwanese data are applied to

populations with adequate selenium

intakes (NRC, 1999, pg. 240).’’ The NRC

report cited studies comparing urinary

selenium concentrations and blood

serum selenium concentrations; these

were lower for the Taiwanese by

comparison to other study populations

including people in the U.S.

NRC noted that the ‘‘model choice can

have a major impact on estimated lowdose risks when the analysis is based on

epidemiological data (NRC 1999, pg.

294).’’ NRC noted that EPA’s 1988 risk

assessment used the multistage Weibull

model to estimate a lifetime skin cancer

risk of 1 × 10¥3 for U.S. males exposed

to arsenic at 50 μg/L. In their report NRC

discussed the implications (both in a

general sense and specifically for the

Tseng data) of using data from an

ecological study, and of using grouped

data. They also reported the results of

applying both a multistage Weibull and

a Poisson model. When they re-assorted

data into varying exposure groups, there

38950 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

was a strong effect on the fitted Weibull

model. NRC concluded: ‘‘Thus the fact

that grouping does have a strong effect

provides evidence of additional

measurement error in the arsenic

concentrations being assigned at the

village level (NRC, 1999, pg. 284).’’ NRC

used median village arsenic

concentrations to represent exposure

levels. The Expert Panel (US EPA,

1997d) noted that biases from using

average doses for groups leads to

overestimation of risk.

‘‘* * * [D]espite a distribution of doses in

the population, those individuals exhibiting

effects would tend also to be those who

received the highest doses; because of this,

deriving an average dose based on affected

individuals would to some extent bias risk

estimates upward. Similarly attribution of the

total excess risk in the population to arsenic

exposure alone could also be expected to

inflate the estimate of risk if the population

is also characterized by other risk factors

such as smoking, excess exposure to sunlight,

nutritional status, and so on (US EPA, 1997d,

pg. 31).’’

The Poisson model with a quadratic term

for age and a linear term for exposure fit as

well as the multistage Weibull model, and

had less variability in risks from regrouping

the exposure intervals. Results from the NRC

Poisson model estimations were used in the

EPA analysis of bladder cancer risks.

NRC noted that ‘‘Ecological studies in

Chile and Argentina have observed risks of

lung and bladder cancer of the same

magnitude as those reported in the studies in

Taiwan at comparable levels of exposure.’’

This observation increases confidence in the

risk estimates based on the Tseng data. That

these populations are different in terms of

ethnic background, dietary patterns, and

potential for other exposures also decreases

the level of concern about generalized

applicability of the Taiwanese data for risk

assessment.

EPA considered these various uncertainties

associated with interpretation of the health

effects of arsenic in making risk management

decisions and in selecting an appropriate

regulatory level. The Agency requests

comment on whether we have properly

weighed the uncertainties which

overestimate and underestimate risk of the

proposed MCL.

There is also a measure of uncertainty

about the costs associated with various

possible regulatory levels. EPA has provided

its best estimates of the costs, but recognizes

that a number of stakeholders have

performed independent analyses suggesting

that the costs may be higher than those

estimated by EPA. EPA requests comment on

its cost estimates and any additional

information commenters may have on

possible costs of the rule.

6. Comparison of Benefits and Costs

The monetized costs and monetized

benefits of the proposed rule, and the

methodologies used to calculate them, are

discussed in detail in sections IX, X, and XIII

of this preamble and in the HRRCA. Overall

estimates of monetized costs and monetized

benefits associated with various MCL options

are provided in Table XI–1. There are also

many health effects which have not been

monetized, as is also shown in Table XI–1.

TABLE XI–1.—ESTIMATED COSTS AND BENEFITS FROM REDUCING ARSENIC IN DRINKING WATER

[In 1999 $ millions]

Arsenic level

(μg/L)

Total national

costs to

CWSs 1

Total national

costs to CWSs

and

NTNCWSs 2

Total bladder

cancer health

benefits 3

‘‘What if’’ scenario 4 and potential non-quantified benefits

‘‘What if’’ lung

cancer health

benefits estimates

Potential non-quantifiable health benefits

3 ...................................... 643.1–753 644.6–756.3 43.6–104.2 5 (79)47.2–448

6 (213.4)

• Skin Cancer.

• Kidney Cancer.

• Cancer of the Nasal Passages.

5 ...................................... 377.3–441.8 378.9–444.9 31.7–89.9 5 (64.3)35–384

6 (173.4)

• Liver Cancer.

• Prostate Cancer.

• Cardiovascular Effects.

10 .................................... 163.3–191.8 164.9–194.8 17.9–52.1 5 (37)19.6–224 6 (100)• Pulmonary Effects.

• Immunological Effects.

• Neurological Effects.

20 .................................... 61.6–72.9 63.2–77.1 7.9–29.8 5 (19.8)8.8–128

6 (53.4)

• Endocrine Effects.

• Reproductive and Developmental Effects.

1 Costs include treatment, monitoring, O&M, and administrative costs to CWSs and State costs for administration of water programs. The lower

number shows costs annualized at a consumption rate of interest of 3%, EPA’s preferred approach. The higher number shows costs annualized

at 7%, which represents the standard discount rate preferred by OMB for benefit-cost analyses of government programs and regulations. 2 Costs include treatment, monitoring, O&M, administrative costs to CWSs; monitoring and administrative costs to NTNCWSs; and State costs

for administration of water programs. 3The upper bound estimate includes an adjustment to account for a possible mortality risk of 80%. It is possible that this risk could have been

below 80%, which would lead to increased benefits. The actual risk depends on the survival rate for bladder cancer in the area of Taiwan studied

by Chen, which is unknown. 4These estimates are based on the ‘‘what if’’ scenario for lung cancer, where the risks of a fatal lung cancer case associated with arsenic are

assumed to be 2–5 times that of a fatal bladder cancer case. 5The number in parentheses indicates the bladder cancer health benefits assuming an 80% mortality rate for bladder cancer in the area of the

Chen study, and starting from the midpoint of the benefits range when mortality and incidence are assumed equivalent. 6The number in parentheses is the midpoint of the range and corresponds to an assumption that the risk of fatal lung cancer is 3.5 times the

risk of fatal bladder cancer.

7. Conclusion and Request for Comment

In summary, based on the NRC report,

EPA agrees that the current MCL of 50

μg/L is too high and must be made more

protective of human health. Because

EPA is proposing an MCLG for arsenic

of 0, the MCL must be set as close as

feasible to the MCLG, unless EPA

invokes its discretionary authority to set

a different MCL at a level where the

costs are justified by the benefits. EPA

believes that the feasible level for

arsenic is 3 μg/L. Today, EPA is

proposing that the arsenic MCL be set at

5 μg/L.

EPA believes that setting the MCL at

3 μg/L, the feasible level in this case,

may not be justified at this time, given

the uncertainty regarding the

relationship between the monetized

benefits and the monetized costs at that

level, the current uncertainty of the nonmonetized benefits, and the degree of

scientific uncertainty regarding the

dose-response curve for an MCL at that

level (affected by differences in

nutrition and arsenic from food).

Because there is a substantial possible

imbalance between currently estimated

monetized costs and benefits at the

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38951

feasible level of 3 μg/L, and a lack of

certainty concerning the non-monetized

costs and potential non-monetized

benefits, EPA is proposing a standard

other than the feasible level, using its

discretionary authority in section

1412(b)(6). (See Senate Rep. 104–169,

104th Cong., 1st Sess. at 33). The statute

requires that a level proposed or

promulgated using this discretionary

authority be one which maximizes

health risk reduction at a level where

the costs are justified by the benefits.

EPA believes that the 5 μg/L MCL best

meets this statutory test. EPA solicits

comment on this finding, as described

in more detail below.

As discussed earlier in section

XI.A.4., EPA believes that there are a

number of not yet quantified adverse

health effects that pose a significant risk

to public health. While the relationship

of actual monetized benefits to

monetized costs at 5 μg/L, $31.7–$89.9

million for bladder cancer benefits (plus

possible lung cancer benefits of $35–

$384 million based on the ‘‘What If’’

scenario) vs. $378.9–444.9 million in

costs, is uncertain. EPA believes the

range of benefits supports that level,

especially when there may potentially

be substantial non-monetized benefits

factored into the analysis. EPA believes

that, given the guidance of the NRC

report, these potential non-monetized

benefits, including a number of noncancer health effects (see Table XI–1),

are substantial enough to strike a

reasonable balance between benefits and

costs. Strict parity of monetized costs

and monetized benefits is not required

to find that the benefits of a particular

MCL option are justified under the

statutory provisions of § 1412(b)(6). In

addition, at 5 μg/L, the remaining risks

(of bladder cancer) to the exposed

population after the rule’s

implementation are well within the

10¥4 range, which is protective of

public health. As a result, EPA finds

that the actual risk levels (including

risks of potential non-monetized health

effects) at 5 μg/L are high enough to

justify this MCL, and it is therefore the

level which maximizes health

protection at a level where the costs are

justified.

As discussed earlier, EPA has, as a

matter of policy typically established

MCLs for cancer-causing contaminants

to ensure that the risks of excess cancer

deaths represented by exposure to

drinking water at the MCL over the

course of a lifetime are within a range

of one in 10,000 to one in 1,000,000.

EPA believes that this range is

reasonably protective of public health

consistent with the goals of the Safe

Drinking Water Act. In using its

statutory discretion under section

1412(b)(6)(A) to set a standard less

stringent than the feasible level that

maximizes health risk reduction at a

cost that is justified by the benefits, EPA

is proposing that it should choose a

level that falls within the aforementioned target risk range. EPA is

proposing to stay within this risk range

even if the monetized benefits of a

standard set at the upper end of the

range are below the costs, as may be the

case with this rule. EPA believes that

important factors in this evaluation are

the considerable non-quantifiable

benefits that may be attributable to the

proposed MCL. EPA also notes, as

discussed earlier, that Congress did not

direct EPA to ensure strict equality of

monetizable costs and benefits in

applying its discretionary authorities

under section 1412(b)(6)(A). EPA

requests comments on its proposed use

of the new authority under section

1412(b)(6)(A) of the SDWA.

The risk assessment for bladder

cancer indicates that a standard set at 10

μg/L would fall at the upper end of the

target risk range, with 5 μg/L more

solidly within that risk range. However,

there are two important sets of

considerations when using available

health effects information and studies to

help determine the appropriate level for

a proposed new standard. On the one

hand, multiple health endpoints are of

concern in ensuring that the standard is

adequately protective. As noted earlier,

the NRC expresses concern about lung

cancer and other health endpoints and

indicated that excess lung cancer deaths

from arsenic in drinking water could be

2–5 times the level of bladder cancer

deaths. If these other risks were fully

quantified, the total risk at 10 μg/L

might be well above 1 × 10¥4 (the upper

end of the risk range), given that the

quantified risk of bladder cancer alone

appears to be at approximately this

level.

On the other hand, there is

uncertainty in the quantification of

bladder cancer risk (as well as other

health endpoints) and this risk estimate

includes a number of conservative

assumptions, as discussed previously.

These include the assumptions of using

a linear dose-response function; the fact

that the dose-response data from the

Taiwan epidemiologic study are based

upon grouped occurrence information

from wells used by the study

population; and the possibility that the

study population was more susceptible

to arsenic in drinking water (as

compared to the U.S. population) due to

the relatively high dietary intake and

dietary deficiencies in other elements (e.g.,

selenium) that might mitigate the results

of arsenic. Thus, the risk of bladder

cancer alone might be well below

current estimates which represent EPA’s

best estimate at this time using currently

available data and standard

methodologies. The proposed MCL

attempts to balance these countervailing

considerations in establishing a level

that is protective of public health.

Given these competing sources of

uncertainty, EPA believes it is

appropriate to propose a standard at 5

μg/L, because at this level it is more

likely that the total risk would be within

the target range than at a higher

standard. However, between now and

promulgation of the final rule, EPA will

work to resolve as much of this

uncertainty as possible, both in terms of

quantifying risk of additional health

endpoints (e.g., lung cancer) and in

terms of reexamining conservative

assumptions in the risk estimate. EPA

requests comment on its proposed level

of 5 μg/L and on its rationale for

selecting this level. In selecting the final

level of the standard, EPA will evaluate,

in light of comments received and any

new scientific information, its proposed

way of using its discretionary authority

under section 1412(b)(6)(A) and the

total risk, costs, and benefits associated

with each of the levels of the standard

under consideration.

EPA requests comment on other

potential MCLs and which of the MCLs

and rationales presented here best fits

the statutory framework. First, EPA is

requesting comment on setting the MCL

at 10 μg/L. The monetized costs of

$164.9–$194.8 million, and monetized

benefits of $17.9–$52.1 million for

bladder cancer (plus possible lung

cancer benefits of $19.6–$224 based on

the ‘‘What If’’ scenario) are closer at 10

μg/L. The risk levels (of bladder cancer)

to the exposed population are within

the 10¥4 risk range, and the

uncertainties already discussed in

Section XI.A.6. may be a basis for

inferring lower expected possible nonmonetized benefits than assumed for the

MCL option of 5 μg/L.

EPA is also requesting comment on an

MCL option of 20 μg/L. Some

stakeholders favor an MCL in this range

and cite, as justification for such a level,

their belief that if all uncertainties are

taken into consideration, risk estimates

would be within the Agency’s risk range

of range of 1 × 10¥6 to 1 × 10¥4. As can

be seen from Table XI–1, costs are

considerably reduced at this level, since

far fewer CWSs would be impacted (i.e.,

occurrence of arsenic, without

treatment, is already below this level for

many systems). Approximately 1,200

CWSs would be projected to incur costs

of approximately $63–$77 million to

38952 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

comply with an MCL of 20 μg/L.

Benefits would also be considerably

lower than for other options, at $7.9–

$29.8 million for bladder cancer (plus

possibly $8.8–$128 million for lung

cancer, based on the ‘‘What If’’

scenario). EPA’s principal concern with

an MCL option in this range is that it

may not be sufficiently protective after

consideration of all health endpoints of

concern. In other words, when the

effects of bladder cancer, lung cancer,

and skin cancer are considered, together

with the various non-quantifiable

endpoints such as circulatory system

impacts, an MCL option of 20 μg/L

could result in an unacceptably high

risk, well outside of the risk range of 1

× 10¥6 to 1 × 10¥4. As noted above, in

using its statutory discretion to set a

standard above the feasible level, EPA is

proposing not to set a standard that

exceeds this target risk range. However,

EPA solicits comment on an MCL

option of 20 μg/L along with any

supporting rationale that commenters

wish to offer.

EPA is also requesting comment on

setting the MCL at 3 μg/L. As explained

in section XI.A.1., this is the level as

close to the MCLG as is feasible. It is

also the level at which the risks are most

solidly within the 10¥4 risk range of the

three MCLs considered. If EPA were to

set the MCL at this level, EPA would not

use its discretionary authority to set the

MCL at a less stringent level based on

costs and benefits. The Agency

estimates that the likelihood that actual

monetized benefits of $43.6–$104.2

million for bladder cancer (plus possible

lung cancer benefits of $47.2–$448

million based on the ‘‘What If’’

scenario), are close to monetized costs

of $644.6–$756.3 million is less certain

than at 5 μg/L. (See Table XI–1.) While

EPA believes that benefits may be

substantially less than monetized costs

for the feasible level, the feasible level

would be the most protective of the

options presented here and would

conservatively account for the

uncertainties about the severity of

various health effects endpoints and

their potential additive impacts.

Finally, Congress indicated interest in

assuring that EPA considered impacts of

an MCL decision on people served by

large systems who could afford

protective MCLs and an MCL of 3 would

respond to this interest. Section

1412(b)(6)(B), however, provides that

the interests of people served by large

systems are to be considered along with

benefits and costs to systems not

expected to get small system variances.

Because this proposal does not include

small system variance technologies (i.e.,

affordable technologies for small

systems at the proposed MCL have been

identified), the interests of persons

served by large and small systems are

being considered together and the

provisions of section 1412(b)(6)(B) do

not apply in this case.

B. Why Is EPA Proposing a Total

Arsenic MCL?

The previous drinking water standard

for arsenic of 0.05 mg/L was based on

total arsenic. Total arsenic includes the

dissolved and undissolved arsenic

species present in drinking water and

makes no distinction between inorganic

or organic species. Consistent with the

previous standard for arsenic, today’s

proposed regulation of 0.005 mg/L will

be based on total arsenic. From an

occurrence and analytical methods

standpoint, the Agency believes it is

inappropriate to make a regulatory

distinction between inorganic and

organic arsenic forms in drinking water.

According to Irgolic (1994) and as

mentioned in section II.B, the inorganic

arsenic species (As III and As V) are

present in drinking water, and organic

arsenic compounds are rarely found in

water supplies. Furthermore, inorganic

As V (arsenate) is more prevalent in

drinking water supplies than inorganic

As III (arsenite), which tends to occur in

anaerobic waters. If organic species are

present in drinking water,

methylarsonic acid (MMA) and

dimethylarsonic acid (DMA) are the

predominant organic forms. These

organic species, when present, can

result from the leaching of arseniccontaining herbicides or from the

conversion of the inorganic forms to the

organic forms in the presence of

microbial activity. In arsenic-rich

ground water wells from Taiwan,

methylated compounds were not

present above concentrations of 1 μg/L.

No DMA or MMA was detected in the

ground water samples from six districts

in West Bengal, India (Chatterjee et

al.,1995). Regarding surface water,

Anderson and Bruland (1991) reported

that organic species (DMA and MMA)

accounted for 1 to 59% of the total

arsenic concentration from fourteen lake

and river samples taken in California.

As Irgolic pointed out in his review of

the Anderson and Bruland study, the

level of the organic arsenic found in

these surface water samples were in the

low nanomolar (nM or nm/L) range.

After converting the reported units from

nm/L to μg/L, analysis of the Anderson

and Bruland data indicate that only two

of the fourteen water samples exceeded

a concentration of 1 μg/L of organic

arsenic (DMA and MMA combined).

There is currently no EPA approved

method for arsenic analysis in drinking

water that distinguishes inorganic

arsenic species from organic arsenic

forms. The method would need to meet

the criteria listed in section VI.B. and

would require interlaboratory studies

for validation. The estimated costs of

such an analytical method could range

from $150 to $250 per analysis. In

addition, laboratory capacity for this

type of method would most likely be

limited at this time.

Few toxicity studies exist for organic

arsenicals. The NRC report noted that

methylated arsenic has less

developmental toxicity than inorganic

arsenic. Concentrations of DMA

administered that decreased fetal weight

produced over 50% maternal mortality

in studies with rats and mice (Rogers et

al., 1981 as reported in NRC, 1999);

hamsters had no developmental toxicity

from exposure to MMA nor DMA

(Willhite, 1981, as reported in NRC,

1999). NRC noted that EPA has two

unpublished studies of rats fed MMA

which had some increase in thyroid

tumors, but no effect on mice. In

addition, MMA and DMA produced

mutations in cells at concentrations over

one thousand times higher than the

concentrations of inorganic arsenite and

arsenate (Moore et al., 1997 as reported

in NRC, 1999). It takes roughly ten times

more DMA than arsenite to cause

chromosome changes in a human cell

line (Oya-Ohata et al., 1996, as reported

in NRC, 1999).

Because of the limited occurrence of

organic arsenic species in water and the

lack of a suitable and widely available

analytical method for inorganic arsenic,

the Agency believes compliance with

the proposed arsenic standard of 0.005

mg/L should be based on total arsenic.

EPA requests comments on setting the

MCL based on total arsenic and any data

or established analytical methods that

would support setting an MCL based on

inorganic arsenic.

C. Why Is EPA Proposing To Require

Only Monitoring and Notification for

NTNCWSs?

In this rulemaking, the Agency is

soliciting comment on an approach

which would not extend coverage of the

rule to Non-Transient Non-Community

(NTNC) water systems, but would

instead create an intermediate level of

control for these systems (monitoring

and notification requirements). The

suggested approach would recognize the

lower level of risk generally posed to

individuals by these systems.

Simultaneously, it would provide a

mechanism for the public to be

adequately informed in those situations

where unusual concentrations of NTNC

systems, customer overlap, and high

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38953

3Throughout this discussion, exposures and risks

were only considered for populations potentially

addressable by regulation, i.e., systems with present

arsenic levels in excess of 3 μg/L.

4For example, airports constitute only about a

hundred of the NTNC water systems. Washington’s

Reagan National and Dulles, Dallas/Fort Worth,

Seattle/Tacoma, and Pittsburgh airports are the five

largest of the airports. SDWIS reports that these five

airports serve about 300,000 people. In actuality,

Bureau of Transportation Statistics suggest that they

serve about eleven million passengers per year.

Examination of this information and other BTS

statistics suggests that these airports serve closer to

seven million unique individuals over the course of

a year and that exposure occurs on an average of

ten times per year per individual customer, not 270

times.

local arsenic water concentrations

caused risk levels to more closely

approach community water system

levels.

There are approximately 20,000

NTNCs water systems regulated under

the Safe Drinking Water Act. By

definition, these systems do not serve

over 25 people as year round residents,

as would be the case for a community

water system. However, they must serve

at least 25 of the same people for over

six months out of the year, or they

would be classified as Transient NonCommunity (TNC) water systems. It is

generally an important distinction since

the Agency has not applied regulations

for contaminants with chronic health

effects to TNC water systems, while it

often has regulated NTNC systems

similar to community water systems

when addressing the risks posed by

chronic contaminants.

In the case of arsenic, the existing

regulation does not apply to NTNC

systems. While it is feasible to control

arsenic in NTNC water systems,

extending regulation to these systems

needs to be considered in light of the

new SDWA requirement to determine

whether the benefits extending coverage

to this category would justify the costs

and whether such regulation would

provide a reasonable opportunity for

health risk reduction. As discussed

elsewhere in the preamble, this analysis

requires a balancing of both quantitative

and non-quantitative factors. Based on

the modeling to be discussed, the

ninetieth percentile lifetime risk of

contracting bladder cancer posed to an

individual consuming water from a

NTNC water system, even in their

present untreated state, does not exceed

one in 100,000. 3 As a consequence,

costs per each bladder cancer case

avoided at the proposed MCL would

approach the fifty million dollar mark if

coverage of the rule were extended to

NTNCs. This level is well above the

range of historical environmental risk

management decisions.

These much lower risk levels result

because most individuals served by

NTNC systems are expected to receive

only a small portion of their lifetime

drinking water exposure from such

systems. For example, even with twelve

years of perfect attendance at schools

served by NTNC water systems, the

water consumed by an individual

student is estimated to represent less

than five percent of lifetime

consumption.

On the other hand, there are some

segments of the NTNC water system

population where exposure is a more

significant portion of the total lifetime

exposure. Manufacturing and other

workers, although they represent only

five percent of the population served by

NTNC systems, could receive twenty to

forty percent of their lifetime exposure

at work. Nevertheless, as manufacturing

workers represent a small portion of the

NTNC population, overall risks among

the NTNC population are small.

Another factor of potential concern is

the extent to which users of the different

NTNC water systems overlap. It is

conceivable that some areas in the

country exist where individuals are

subjected to arsenic exposure at a

number of different non-community

systems (e.g., day care center plus

school plus factory, etc.). In such

circumstances, individuals would be

exposed to proportionately higher risks

if the water systems all had elevated

arsenic levels. For some individuals, the

exposure could approach levels

observed in corresponding community

water systems. This concern is

alleviated by the fact that NTNC systems

generally serve only a very small

portion of the total population. For

example, over ninety-five percent of all

school children are served by

community water systems. Only a small

percentage are served by NTNC water

systems and, of that group, only about

twelve percent (or less than one half of

one percent of the overall student

population) would be expected to have

arsenic in their water above the

proposed regulatory level). Likewise,

less than 0.1 percent of the work force

population receive water from an NTNC

water system. With such low portions of

the total population exposed to any

particular type of NTNC system, the

overall likelihood of multiple exposure

cases in the NTNC population should

also be small. The groups have been

treated independently for this analysis.

Comment and data are solicited to

support any alternative treatments of the

exposure data.

Finally, although the Agency does not

believe there is sufficient evidence to

support unusual sensitivity on the part

of children, they generally do consume

more water on a weight adjusted basis.

For this reason, NTNC systems which

were likely to pose the greatest exposure

risk to children were separately

examined and their higher relative

doses considered in the modeling effort.

All of these factors contributed to the

Agency’s evaluation of whether or not to

extend regulation to NTNC water

systems for arsenic and are discussed

further in the results section.

1. Methodology for Analyzing NTNCWS

Risks

Determination of system and

individual exposure factors—In the

past, the Agency has directly used

SDWIS population estimates for

assessing the risks posed to users of

NTNC water systems. In other words, it

was assumed that the same person

received the exposure on a year round

basis. Under this approach it was

generally assumed that all NTNC users

were exposed for 270 days out of the

year and obtained fifty percent of their

daily consumption from these systems.

TNC users were assumed to use the

system for only ten days per year.

With the recent completion of

‘‘Geometries and Characteristics of

Public Water Systems (US EPA,

1999e),’’ however, the Agency has

developed a more comprehensive

understanding of NTNC water systems.

These systems provide water in due

course as part of operating another line

of business. Many systems are classified

as NTNC, rather than TNC, water

systems solely because they employ

sufficient workers to trigger the ‘‘25

persons served for over six months out

of the year’’ requirement. Client

utilization of these systems is actually

much less and more similar to exposure

in TNC water systems. For instance, it

is fairly implausible that highway rest

areas along interstate highways serve

the same population on a consistent

basis (with the exception of long

distance truckers). Nevertheless, there

are highway rest areas in both NTNC

and TNC system inventories. The

‘‘Geometries’’ report suggests that

population figures reported in SDWIS

which have been used for past risk

assessments generally appear to reflect

the number of workers in the

establishment coupled with peak day

customer utilization.

Under these conditions use of the

SDWIS figures for population greatly

overestimates the actual individual

exposure risk for most of the exposed

population and also significantly

underestimates the number of people

exposed to NTNC water.4 Adequately

characterizing individual and

38954 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

5For example, travel industry statistics provide

information on total numbers of hotel stays,

vacancy rates, traveller age ranges, and average

duration of stay. These figures can be combined

with the SDWIS peak day population estimates to

allocate daily population among workers, customers

and vacancies. The combination of these factors

provides an estimate of the number of independent

customer cycles experienced in a year.

6For example, school kid water consumption was

weighted to reflect consumption between ages 6

and 18, while factory worker consumption was

weighted over ages 20 to 64.

population risks necessitates some

adjustments to the SDWIS population

figures. For chronic contaminants, such

as arsenic, health data reflect the

consequences of a lifetime of exposure.

Consequently, risk assessment requires

the estimation of the portion of total

lifetime drinking water consumption

that any one individual would receive

from a particular type of water system.

In turn, one needs to estimate the

appropriate portions for daily, days per

year, and years per lifetime

consumption. These estimates need to

be prepared for both the workers at the

facility and the ‘‘customers’’ of the

facility.

This adjustment was accomplished

through a comprehensive review of

government and trade association

statistics on entity utilization by the

U.S. Department of Commerce’s

Standard Industrial Classification (SIC)

code. These figures, coupled with

SDWIS information relating to the

portion of a particular industry served

by non-community water systems, made

possible the development of two

estimates needed for the risk

assessment: customer cycles per year

and worker per population served per

day. These numbers are required to

distinguish the more frequent and

longer duration exposure of workers

from that of system customers.5 A more

detailed characterization of the

derivation of these numbers is

contained in the docket. Table XI–2

provides the factors used in the NTNC

risk assessment to account for the

intermittent nature of exposure.

Comment is solicited on the

appropriateness of the various factors.

Once the population adjustment

factors were derived, it was possible to

determine the actual population served

by NTNC water systems. Table XI–3

provides a breakout of these figures by

type of establishment. Although not

included in Table XI–3, there are other

equally important characteristics to note

about these systems. With notable

exceptions (such as the airports in

Washington, DC and Seattle), the

systems generally serve a fairly small

population on any given day. In fact, 99

percent of the systems serve less than

3300 users on a daily basis. This means

that water production costs will be

relatively high on a per gallon basis.

Risk calculation—Calculations of

individual risk were prepared for each

industrial sector. Even within a given

sector, however, risk varies as a function

of an individual’s relative water

consumption, body weight,

vulnerability to arsenic exposure, and

the water’s arsenic concentration.

Computationally, risks were estimated

by performing Monte Carlo modeling, as

was done in the community water

system risk estimation, with two

exceptions. First, each realization in a

given sector was multiplied by the

portion of lifetime exposure factor

presented in Table XI–2 to reflect the

decreased consumption associated with

the NTNC system. Secondly, relative

exposure factors were limited to age

specific ratings where appropriate.6 For

example, in the case of school children,

water consumption rates and weights

for six to eighteen year olds were used.

TABLE XI–2.—EXPOSURE FACTORS USED IN THE NTNC RISK ASSESSMENT

NTNCWS

Number of

cycles per

yr

Worker/pop/

day

Worker fraction dailyWorker

days/yr

Worker

exposure

years

Customer

fraction

daily

Days of use/

yr

Customer exposure years

Water wholesalers ....... 1.00 0.000 0.25 270 70

Nursing homes ............. 1.00 0.230 0.50 250 40 1.00 365 10

Churches ...................... 1.00 0.010 0.50 250 40 0.50 52 70

Golf/country clubs ........ 4.50 0.110 0.50 250 40 0.50 52 70

Food retailers ............... 2.00 0.070 0.50 250 40 0.25 185 70

Non-food retailers ........ 4.50 0.090 0.50 250 40 0.25 52 70

Restaurants .................. 2.00 0.070 0.50 250 40 0.25 185 70

Hotels/motels ............... 86.00 0.270 0.50 250 40 1.00 3.4 40

Prisons/jails .................. 1.33 0.100 0.50 250 40 1.00 270 3

Service stations ............ 7.00 0.060 0.50 250 40 0.25 52 54

Agricultural products/

services .................... 7.00 0.125 0.50 250 40 0.25 52 50

Daycare centers ........... 1.00 0.145 0.50 250 10 0.50 250 5

Schools ........................ 1.00 0.073 0.50 200 40 0.50 200 12

State parks ................... 26.00 0.016 0.50 250 40 0.50 14 70

Medical facilities ........... 16.40 0.022 0.50 250 40 1.00 6.7 10.3

Campgrounds/RV ......... 22.50 0.041 0.50 180 40 1.00 5 50

Federal parks ............... 26.00 0.016 0.50 250 40 0.50 14 70

Highway rest areas ...... 50.70 0.010 0.50 250 40 0.50 7.2 70

Misc. recreation service 26.00 0.016 0.50 250 40 1.00 14 70

Forest Service .............. 26.00 0.016 1.00 250 40 1.00 14 50

Interstate carriers ......... 93.00 0.304 0.50 250 40 0.50 2 70

Amusement parks ........ 90.00 0.180 0.50 250 10 0.50 1 70

Summer camps ............ 8.50 0.100 1.00 180 10 1.00 7 10

Airports ......................... 36.50 0.308 0.50 250 40 0.25 10 70

Military bases ............... 1.000 0.50 250 40

Non-water utilities ........ 1.000 0.50 250 40

Office parks .................. 1.000 0.50 250 40

Manufacturing: Food .... 1.000 0.50 250 40

Manufacturing: Nonfood ........................... 1.000 0.50 250 40

Landfills ........................ 1.000 1.00 250 40

Fire departments .......... 1.000 1.00 250 40

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38955

7Community ground water occurrence

information was used since NTNC systems are

almost exclusively supplied by ground water

sources. Further, as there was no depth dependence

of arsenic levels observed in the community

information, it is believed that the data are an

adequate approximation.

TABLE XI–2.—EXPOSURE FACTORS USED IN THE NTNC RISK ASSESSMENT—Continued

NTNCWS

Number of

cycles per

yr

Worker/pop/

day

Worker fraction dailyWorker

days/yr

Worker

exposure

years

Customer

fraction

daily

Days of use/

yr

Customer exposure years

Construction ................. 1.000 1.00 250 40

Mining ........................... 1.000 1.00 250 40

Migrant labor camps .... 1.000 1.00 250 40

TABLE XI–3.—COMPOSITION OF NON-TRANSIENT, NON-COMMUNITY WATER SYSTEMS

[Percentage of total NTNC population served by sector]

Schools ......................... 9.7 Medical Facilities .......... 8 Interstate Carriers ......... 7.1 Campgrounds ............... 1.3

Manufacturing ............... 2.7 Restaurants .................. 0.9 State Parks ................... 8.6 Misc Recreation ............ 1.8

Airports ......................... 26.1 Non-food Retail ............ 1.6 Amusement Parks ........ 17.7 Other ............................. 3.5

Office Parks .................. 0.6 Hotels/Motels ................ 9.2 H’way Rest Area .......... 1.0

To illustrate the process, it was conservatively assumed that a child would attend only NTNC served schools for

all twelve years. Further, it was assumed that a child would get half of their daily water consumption at school

(for an average first grader this would correspond to roughly nine ounces of water per school day). Finally, it was

assumed that the child would have perfect attendance and attend school for 200 days per year. Table XI–4 provides

a sample output for the upper bound individual risk distribution to school children resulting from exposure to the

range of untreated arsenic observed in community ground water systems 7 as well as an estimate based on more moderate

assumptions of four ounces per day and 150 days attendance for four years. Upper and lower bound risk distributions

were prepared for both workers and ‘‘customers’’ at all types of NTNC water systems and are contained in the docket.

TABLE XI–4.—UPPER BOUND SCHOOL CHILDREN RISK ASSOCIATED WITH CURRENT ARSENIC EXPOSURE IN NTNC

WATER SYSTEMS

[Risks are per 10,000 students. i.e., × 10¥4]

Moderate exposure scenarioUpper bound

scenario

Mean Lifetime Risk .............................................................................................................................................. 0.0087 0.079

90th Percentile Lifetime Risk ............................................................................................................................... 0.019 0.17

Lifetime Bladder Cancers in Student Population ................................................................................................ 0.5 4.5

Note: This table does not include potential non-quantified lung or skin cancers.

The distribution of population risks

overall was determined as part of the

same simulation by developing sector

weightings to reflect the total portion of

the NTNC population served by each

sector. Population weighted

proportional sampling of the individual

sectors provided an overall distribution

of risk among those exposed at NTNC

systems.

2. Results

It is important to note that the results

presented in the discussion of NTNC

benefits are based on the currently

quantified health endpoint for arsenic

related bladder cancer. As noted

elsewhere in Section X of today’s

proposal, there are a number of health

end points that have not yet been

quantified and which could provide a

rationale for extending coverage to

NTNCs—in the event that a substantial

portion of the consumers of water from

such systems fall outside the 1 in 10,000

risk range frequently used by the

Agency as a benchmark for such

decisions. (Any additional data

quantifying such endpoints would made

available for public comment in a

Notice of Data Availability.)

Table XI–5 presents a summary of the

Benefit Cost Analysis for all NTNC

systems. As can be seen from a review

of the Table, regulation of arsenic in

NTNC water systems provides only very

limited opportunity for national risk

reduction. Table XI–6 presents risk

figures for three particular sets of

individuals: children in daycare centers

and schools, and construction workers.

Construction and other strenuous

activity workers comprise an extremely

small portion of the population served

by NTNC systems (less than 0.1%), but

face the highest relative risks of all

NTNC users (90th percentile risks of 0.7

to 1.6 × 10¥4 lifetime risk).

Nevertheless, there is considerable

uncertainty about these exposure

numbers. It is quite likely that they

overestimate consumption and may be

revised downward by subsequent

analysis (Any additional data

quantifying such endpoints would made

available for public comment in a

Notice of Data Availability.). The risks

for children are much lower with an

upper bound, 90th percentile estimate

of 1.7 × 10¥5 lifetime risk.

What is not possible to determine

from the analysis of NTNC systems is

the extent to which there is overlap of

individual exposure between the

various sectors. As mentioned earlier,

NTNC establishments generally

constitute a small portion of their SIC

sectors. This fact and the observation

that NTNC populations would only

serve about one percent of the total

population if all of the sectors with

significant exposure (greater than five

percent of lifetime) if they were

38956 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

8This is considerably less than the estimated

rural population in the U.S. which is the smallest

group among which users of these systems would

conceivably be distributed.

mutually exclusive, 8 provide some

support for treating the SIC groups

independently. However, it is equally

plausible that there are communities

where one individual might go from an

NTNC day care center to a series of

NTNC schools and then work in an

NTNC factory.

The Agency is concerned about the

potential for local issues to arise with

respect to combined arsenic exposures.

In the rare community where all ground

water is contaminated with the highest

levels of arsenic, risks could be outside

of the Agency’s traditionally allowable

realm. Further, different levels of

protection being provided by schools

served by community water systems

versus those served by NTNC systems

could be seen as posing equity

considerations for rural communities.

For all of these reasons, the Agency does

not believe it is appropriate to

completely exempt NTNC systems from

arsenic regulation. On the other hand, it

does not believe an adequate basis exists

to prescribe a standard.

The Agency is proposing to take a

somewhat different approach with

respect to NTNC water systems than

previously practiced. We are proposing

that NTNC water systems be subject to

arsenic monitoring requirements

applicable to community water systems.

When an individual NTNC system has

arsenic present in excess of the MCL for

community systems, it would be

required to post a notice to customers as

described in Section VII.I. of this rule.

The Agency believes that this approach

will provide localities with high arsenic

concentrations the opportunity to limit

their consumption of water from these

systems. Because the NTNC is not the

sole source of water available to these

consumers as would be the case with a

community water system, they would

have the ability to use bottled water, or

in the case of schools for instance, to

install voluntary treatment to reduce

their exposure.

The Agency requests comment on this

approach for addressing NTNC water

systems as well as on two other possible

approaches: exempting NTNC systems

entirely from coverage under this rule or

extending coverage to NTNC systems in

the same manner as CWSs. EPA requests

an accompanying rationale and any data

commenters wish to submit as part of

their comments on this topic. The

Agency may decide, as part of the final

rule, to incorporate any of these three

approaches without further opportunity

for comment (except where a NODA

may be issued to provide the public

with additional new information not

taken into consideration for today’s

rulemaking).

TABLE XI–5.—NON-TRANSIENT NON-COMMUNITY BENEFIT COST ANALYSIS

[All risk values are per 10,000-i.e., 10¥4]

MCL option

Untreated 10 5 3

Lower

bound

Upper

bound

Lower

bound

Upper

bound

Lower

bound

Upper

bound

Lower

bound

Upper

bound

Mean Individual Risk ........................................ 0.019 0.042 0.012 0.026 0.0077 0.017 0.0046 0.01

90th Percentile Individual ................................. 0.037 0.08 0.027 0.058 0.017 0.037 0.01 0.022

Annual Bladder Cancers .................................. 0.427 0.95 0.265 0.583 0.16 0.36 0.101 0.215

Cancer Cases Avoided .................................... 0 0 0.162 0.367 0.267 0.59 0.326 0.735

Benefit Million Dollars ...................................... 0 0 0.31 0.70 0.51 1.1 0.62 1.4

Cost Million Dollars .......................................... ................ 0 ................ 6.121 ................ 14.69 ................ 25.21

Note: This table does not include potential non-quantified lung cancer benefits.

TABLE XI–6.—SENSITIVE GROUP EVALUATION LIFETIME RISKS

Group Mean risk 90th percentile

risk

Forest Service, Construction and Mining Workers ...................................................................................... 3.2–7×10¥5 7.2–16×10¥5

School Children ........................................................................................................................................... 3.8–7.9×10¥6 0.84–1.7×10¥5

Day Care Children ....................................................................................................................................... 3.4–6.8×10¥6 0.74–1.5×10¥5

XII. State Programs

A. How Does Arsenic Affect a State’s

Primacy Program?

States must revise their programs to

adopt any part of today’s rule which is

more stringent than the approved State

program. Primacy revisions must be

completed in accordance with 40 CFR

142.12, and 142.16. States must submit

their revised primacy application to the

Administrator for approval. State

requests for final approval must be

submitted to the Administrator no later

than 2 years after promulgation of a new

standard unless the State requests and is

granted an additional 2-year extension.

For revisions of State programs,

§ 142.12 requires States to submit,

among other things, ‘‘[a]ny additional

materials that are listed in § 142.16 of

this part for a specific EPA regulation,

as appropriate (§ 142.12(c)(1)(ii)).’’

Based on comments from stakeholders

at the arsenic in drinking water

regulatory development meetings held

prior to proposal, EPA believes that the

information required in § 142.16(e) is

not required for States revising the MCL

for arsenic. Although that section refers

to applications that adopt requirements

of §§ 141.11, 141.23, 141.32, and 141.62,

EPA believes that existing State

programs which contain the

standardized monitoring framework for

inorganic contaminants (40 CFR 141.23)

can ensure all CWSs monitor for

arsenic. Therefore, EPA is proposing to

clarify that § 141.16(e) applies only to

new contaminants, not revisions of

existing contaminants regulations. The

Agency requests comment on whether

this is an appropriate change.

EPA believes that the requirements in

§ 142.12(c) will provide sufficient

information for EPA review of the State

revision. The side-by-side comparison

of requirements required in

§ 142.12(c)(1)(i) will only consist of

sections revised to adopt the changes

required for the arsenic regulation and

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38957

any other revisions requested by the

State. In addition, the Attorney

General’s statement required in

§ 142.12(c)(1)(iii) will certify that the

revised regulations will be effective and

enforceable. The Agency requests

comment on whether any other

documentation is necessary to approve

revisions to State programs enforcing

the new arsenic regulation.

The Agency is proposing to add

§ 142.16(j) to clarify primacy

requirements relating to monitoring

plans and waiver procedures for

revisions of existing monitoring

requirements such as arsenic. Section

142.16(j) clarifies that the State simply

needs to inform the Agency in their

application of any changes to the

monitoring plans and waiver

procedures. Alternatively, a State may

indicate in the primacy application that

they will use the existing monitoring

plans and waiver criteria approved for

primacy under the National Primary

Drinking Water Standards for other

contaminants (for example, i.e. the

Phase II/V rules). This information may

be provided in the primacy application

crosswalk which identifies revisions to

the State primacy program.

B. When Does a State Have To Apply?

To maintain primacy for the Public

Water Supply (PWS) program and to be

eligible for interim primacy enforcement

authority for future regulations, States

must adopt today’s rule, when final. A

State must submit a request for approval

of program revisions that adopt the

revised MCL and implementing

regulations within two years of

promulgation unless EPA approved an

extension per § 142.12(b). Interim

primacy enforcement authority allows

States to implement and enforce

drinking water regulations once State

regulations are effective and the State

has submitted a complete and final

primacy revision application. To obtain

interim primacy, a State must have

primacy with respect to each existing

NPDWR. Under interim primacy

enforcement authority, States are

effectively considered to have primacy

during the period that EPA is reviewing

their primacy revision application.

C. How Are Tribes Affected?

Currently, no federally recognized

Indian tribes have primacy to enforce

any of the drinking water regulations.

EPA Regions implement the rules for all

Tribes under section 1451(a)(1) of

SDWA. Tribes must submit a primacy

application to have oversight for the

inorganic contaminants (i.e., the Phase

II/V rule) to obtain the authority for the

revised arsenic MCL. Tribes with

primacy for drinking water programs are

eligible for grants and contract

assistance (section 1451(a)(3)). Tribes

are also eligible for grants under the

Drinking Water State Revolving Fund

Tribal set aside grant program

authorized by section 1452(i) for public

water system expenditures.

XIII. HRRCA

A. What Are the Requirements for the

HRRCA?

Section 1412(b)(3)(C) of the 1996

Amendments requires EPA to prepare a

Health Risk Reduction and Cost

Analysis (HRRCA) in support of any

NPDWR that includes an MCL.

According to these requirements, EPA

must analyze each of the following

when proposing a NPDWR that includes

an MCL: (1) Quantifiable and nonquantifiable health risk reduction

benefits for which there is a factual

basis in the rulemaking record to

conclude that such benefits are likely to

occur as the result of treatment to

comply with each level; (2) quantifiable

and non-quantifiable health risk

reduction benefits for which there is a

factual basis in the rulemaking record to

conclude that such benefits are likely to

occur from reductions in co-occurring

contaminants that may be attributed

solely to compliance with the MCL,

excluding benefits resulting from

compliance with other proposed or

promulgated regulations; (3)

quantifiable and non-quantifiable costs

for which there is a factual basis in the

rulemaking record to conclude that such

costs are likely to occur solely as a

result of compliance with the MCL,

including monitoring, treatment, and

other costs, and excluding costs

resulting from compliance with other

proposed or promulgated regulations;

(4) the incremental costs and benefits

associated with each alternative MCL

considered; (5) the effects of the

contaminant on the general population

and on groups within the general

population, such as infants, children,

pregnant women, the elderly,

individuals with a history of serious

illness, or other subpopulations that are

identified as likely to be at greater risk

of adverse health effects due to exposure

to contaminants in drinking water than

the general population; (6) any

increased health risk that may occur as

the result of compliance, including risks

associated with co-occurring

contaminants; and (7) other relevant

factors, including the quality and extent

of the information, the uncertainties in

the analysis, and factors with respect to

the degree and nature of the risk.

This analysis summarizes EPA’s

estimates of the costs and benefits

associated with various arsenic levels.

Summary tables are presented that

characterize aggregate costs and

benefits, impacts on affected entities,

and tradeoffs between risk reduction

and compliance costs. This analysis also

summarizes the effects of arsenic on the

general population as well as any

sensitive subpopulations and provides a

discussion on the uncertainties in the

analysis and any other relevant factors.

B. What Are the Quantifiable and NonQuantifiable Health Risk Reduction

Benefits?

Arsenic ingestion has been linked to

a multitude of health effects, both

cancerous and non-cancerous. These

health effects include cancer of the

bladder, lungs, skin, kidney, nasal

passages, liver, and prostate. Arsenic

ingestion has also been attributed to

cardiovascular, pulmonary,

immunological, neurological, endocrine,

and reproductive and developmental

effects. A complete list of the arsenicrelated health effects reported in

humans is shown in Table X–1. Current

research on arsenic exposure has only

been able to define scientifically

defensible risks for bladder cancer.

Because there is currently a lack of

strong evidence on the risks of other

arsenic-related health effects noted

above, the Agency has based its

assessment of the quantifiable health

risk reduction benefits solely on the

risks of arsenic induced bladder

cancers. It is important to note that if

the Agency were able to quantify

additional arsenic-related health effects,

the quantified benefits estimates may be

significantly higher than the estimates

presented in this analysis.

The quantifiable health benefits of

reducing arsenic exposures in drinking

water are attributable to the reduced

number of fatal and non-fatal cancers,

primarily of the bladder. Table XIII–1

shows the health risk reductions

(number of total bladder cancers

avoided and the proportions of fatal and

non-fatal bladder cancers avoided) at

various arsenic levels.

38958 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

TABLE XIII–1.—RISK REDUCTION FROM REDUCING ARSENIC IN DRINKING WATER 1

Arsenic level 2(μg/L)

Risk reduction

(total bladder

cancers avoided per year)

Risk reduction

(fatal bladder

cancers avoided per year)

Risk reduction

(non-fatal

bladder cancers avoided

per year)

3 ................................................................................................................................................... 22–42 5.7–10.9 16.3–31.1

5 ................................................................................................................................................... 16–36 4.2–9.4 11.8–26.6

10 ................................................................................................................................................. 9–21 2.3–5.5 296

6.7–15.5

20 ................................................................................................................................................. 4–12 1–3 3–9

1The number of bladder cancer cases avoided provide our ‘‘best’’ estimates at this time. The actual number of cases could be lower, given the

various uncertainties discussed, or higher, as these estimates assume a 100% mortality rate. An 80% mortality rate is used in the computation of

upper bound benefits.

The above ranges of total, fatal, and

non-fatal bladder cancer cases are based

on a range of mean bladder cancer risks

for exposed populations at or above

arsenic levels of 3, 5, 10, and 20 μg/L

as shown in Table XIII–2. For example,

if we multiply the risk range at 3 μg/L

(2.1 × 10¥5 to 4.5 × 10¥5) by the

population exposed at 3 μg/L (26.6

million), we find that the total cancers

avoided at this arsenic level range from

22 to 42 bladder cancers per year, when

subtracted from the number of bladder

cancers per year at the baseline (50 μg/

L). Fatal bladder cancer cases are

determined through the relationship

(EPA, 1999a) that approximately 26

percent of the total bladder cancer cases

avoided at each level result in fatalities.

Non-fatal bladder cancer cases are

calculated by subtracting the total

number of cancers from the number of

fatal cancer cases.

TABLE XIII–2.—MEAN BLADDER CANCER RISKS AND EXPOSED POPULATION1

Arsenic level (μg/L) Mean exposed

population risk 2

Total bladder cancer cases avoided

per year 3

Baseline (50 μg/L):

3 ............................................................................................................................................................ 2.1¥4.5×10¥5 22–42

5 ............................................................................................................................................................ 3.6¥7.5×10¥5 16–36

10 .......................................................................................................................................................... 5.5¥11.4×10¥5 9–21

20 .......................................................................................................................................................... 6.9¥13.9×10¥5 4–12

1The population exposed at 3 μg/L or greater is approximately 26.6 million. 2The bladder cancer risks presented in this table provide our ‘‘best’’ estimates at this time. Actual risks could be lower, given the various uncertainties discussed, or higher, as these estimates assume a 100% mortality rate. An 80% mortality rate is used in the computation of upper

bound benefits. 3Total bladder cancer cases avoided could be higher, depending on the survival rate for bladder cancer in the study area of Taiwan for the duration of the study.

The Agency has developed monetized

estimates of the health benefits

associated with the risk reductions from

arsenic exposures. The SDWA, as

amended, requires that a cost-benefit

analysis be conducted for each NPDWR,

and places a high priority on better

analysis to support rulemaking. The

Agency is interested in refining its

approach to both the cost and benefit

analysis, and in particular recognizes

that there are different approaches to

monetizing health benefits.

The approach used in this analysis for

the measurement of health risk

reduction benefits is the monetary value

of a statistical life (VSL) applied to each

fatal cancer avoided. Estimating the VSL

involves inferring individuals’ implicit

tradeoffs between small changes in

mortality risk and monetary

compensation. In this analysis, a central

tendency estimate of $5.8 million

(1997$) is used in the monetary benefits

calculations. This figure is determined

for the VSL estimates in 26 studies

reviewed in EPA’s recent draft guidance

on benefits assessment (US EPA, 1997f).

It is important to recognize the

limitations of existing VSL estimates

and to consider whether factors such as

differences in the demographic

characteristics of the populations and

differences in the nature of the risks

being valued have a significant impact

on the value of mortality risk reduction

benefits. Also, medical care or lost-time

costs are not separately included in the

benefits estimates for fatal cancers, since

it is assumed that these costs are

captured in the VSL for fatal cancers.

For non-fatal cancers, willingness to

pay (WTP) data to avoid chronic

bronchitis is used as a surrogate to

estimate the WTP to avoid non-fatal

bladder cancers. The use of such WTP

estimates is supported in the SDWA, as

amended, at section 1412(b)(3)(C)(iii):

‘‘The Administrator may identify valid

approaches for the measurement and

valuation of benefits under this

subparagraph, including approaches to

identify consumer willingness to pay for

reductions in health risks from drinking

water contaminants.’’

A WTP central tendency estimate of

$536,000 (in 1997 $) is used to monetize

the benefits of avoiding non-fatal

cancers (Viscusi et al., 1991). The fatal,

non-fatal, and non-quantifiable health

benefits are summarized in Table XIII–

3. As expected, the quantified bladder

cancer benefits increase as arsenic levels

decrease.

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38959

TABLE XIII–3.—ESTIMATED COSTS AND BENEFITS FROM REDUCING ARSENIC IN DRINKING WATER

[In 1999 $ millions]

Arsenic level (μg/L)

Total national

costs to

CWSs 1

Total national

costs to CWSs

and

NTNCWSs 2

Total bladder

cancer health

benefits 3

‘‘What if’’ scenario 4 and potential non-quantified benefits

‘‘What if’’ lung

cancer health

benefits estimates

Potential non-quantifiable health benefits

3 ...................................... 643.1–753 644.6–756.3 43.6–104.2 5 (79)47.2–448

6 (213.4)

• Skin Cancer.

• Kidney Cancer.

• Cancer of the Nasal Passages.

5 ...................................... 377.3–441.8 378.9–444.9 31.7–89.9 5 (64.3)35–384

6 (173.4)

• Liver Cancer.

• Prostate Cancer.

• Cardiovascular Effects.

10 .................................... 163.3–191.8 164.9–194.8 17.9–52.1 5 (37)19.6–224 6 (100)• Pulmonary Effects.

• Immunological Effects.

20 .................................... 61.6–72.9 63.2–77.1 7.9–29.8 5 (19.8)8.8–128

6 (53.4)

• Neurological Effects.

• Endocrine Effects.

• Reproductive and Developmental Effects.

1 Costs include treatment, monitoring, O&M, and administrative costs to CWSs and State costs for administration of water programs. The lower

number shows costs annualized at a consumption rate of interest of 3%, EPA’s preferred approach. The higher number shows costs annualized

at 7%, which represents the standard discount rate preferred by OMB for benefit-cost analyses of government programs and regulations. 2 Costs include treatment, monitoring, O&M, administrative costs to CWSs; monitoring and administrative costs to NTNCWSs; and State costs

for administration of water programs. 3The upper bound estimate includes an adjustment to account for a possible mortality risk of 80%. It is possible that this risk could have been

below 80%, which would lead to increased benefits. The actual risk depends on the survival rate for bladder cancer in the area of Taiwan studied

by Chen, which is unknown. 4These estimates are based on the ‘‘what if’’ scenario for lung cancer, where the risks of a fatal lung cancer case associated with arsenic are

assumed to be 2–5 times that of a fatal bladder cancer case. 5The number in parentheses indicates the bladder cancer health benefits assuming an 80% mortality rate for bladder cancer in the area of the

Chen study, and starting from the midpoint of the benefits range when mortality and incidence are assumed equivalent. 6The number in parentheses is the midpoint of the range and corresponds to an assumption that the risk of fatal lung cancer is 3.5 times the

risk of fatal bladder cancer.

Reductions in arsenic exposures may

also be associated with non-quantifiable

benefits. EPA has identified several

potential non-quantifiable benefits

associated with regulating arsenic in

drinking water. In addition to the nonquantifiable benefits noted in Table

XIII–3, these benefits may include any

customer peace of mind from knowing

that their drinking water has been

treated for arsenic. Also, using reverse

osmosis to remove arsenic from

drinking water may also reduce other

contaminants such as sulfate, nitrate,

and iron due to the high removal

efficiency of this treatment technology.

C. What Are the Quantifiable and NonQuantifiable Costs?

The costs of reducing arsenic to

various levels are summarized in Table

XIII–4, which shows that, as expected,

aggregate arsenic mitigation costs

increase with decreasing arsenic levels.

Total national costs range from $646

million per year at 3 μg/L to $65 million

per year at 20 μg/L.

TABLE XIII–4.—ESTIMATED ANNUALIZED NATIONAL COSTS OF REDUCING ARSENIC EXPOSURES

[In 1999 $ millions]

Arsenic level (μg/L) Costs to

CWSs 1

Total national

costs to

CWSs 2

Total national

costs to CWSs

and

NTNCWSs 3

Total cost per fatal bladder

cancer case avoided 4

3 ................................................................................................... 639–746.4 643.1–753 644.6–756.3 59–113 (69.4–132.7)

5 ................................................................................................... 374–436 377.3–441.8 378.9–444.9 40–91 (47–106)

10 ................................................................................................. 160–187 163.3–191.8 164.9–194.8 30.2–70.5 (35.4–84.7)

20 ................................................................................................. 59–68 61.6–72.9 63.2–77.1 20.3–60.7 (26–77.1)1.

1 Costs include treatment and O&M costs only. The lower number shows costs annualized at 3 percent; the higher number shows costs

annualized at 7%. The 7% rate represents the standard discount rate preferred by OMB for benefit-cost analyses of government programs and

regulations. 2 Costs include treatment, monitoring, O&M, and administrative costs to CWSs and State costs for administration of water programs. Costs

annualized at 3 and 7 percent. 3 Costs include treatment, monitoring, O&M, administrative costs to CWSs; monitoring and administrative costs to NTNCWSs; and State costs

for administration of water programs. Costs annualized at 3 and 7 percent. 4 Range based on range of fatal bladder cancer cases avoided per year shown in Table XIII.1. The range of costs per fatal bladder cancer

avoided could be one-half of the value presented, depending on the mortality rate for bladder cancer in the study area of Taiwan for the duration

of the study. A plausible estimate for that mortality rate is 80%.

The cost impact of reducing arsenic in

drinking water at the household level

was also assessed. Table XIII–5

examines the cost per household for

each system size category. As shown in

the table, costs per household decrease

as system size increases. Costs per

household also do not vary significantly

across arsenic levels. This is because

38960 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

costs do not vary significantly with

removal efficiency; once a system

installs a treatment technology to meet

an MCL, costs based upon the removal

efficiency that the treatment technology

will be operated under remain relatively

flat. Per household costs are, however,

somewhat lower at less stringent arsenic

levels. This is due to the assumption

that some systems would blend water at

these levels and treat only a portion of

the flow.

TABLE XIII–5.—ESTIMATED ANNUAL COSTS PER HOUSEHOLD 1 (IN 1999 $) AND (NUMBER OF HOUSEHOLDS AFFECTED)

System size 3 μg/L 5 μg/L 10 μg/L 20 μg/L

25–100 ............................................................................................................. $368

(93,900)

$364

(58,600)

$357

(27,000)

$349

(10,000)

101–500 ........................................................................................................... $259

(366,900)

$254

(229,000)

$246

(103,000)

$238

(41,000)

501–1,000 ........................................................................................................ $106

(356,000)

$104

(223,000)

$98

(102,000)

$93

(41,000)

1,001–3,300 ..................................................................................................... $64 2 (1)$60

(626,000)

$57

(290,000)

$52

(118,000)

3,301–10,000 ................................................................................................... $44 2 (1.6)$41

2 (1)

$37

(478,000)

$33

(196,000)

10,001–50,000 ................................................................................................. $36 2 (3.25)$33 2 (2.1)$29

(998,000

$25

(406,000)

50,001–100,000 ............................................................................................... $30 2 (1.4)$27 2 (0.9)$23

(465,000)

$19

(189,000)

100,001–1 million ............................................................................................. $23 2 (3.1)$21 2 (1.8)$18

(937,000)

$15

(365,000)

1 Costs include treatment and O&M costs to CWSs only.

2 Million.

Costs per household are higher for

households served by smaller systems

than larger systems for two reasons.

First, smaller systems serve far fewer

households than larger systems and,

consequently, each household must bear

a greater percentage share of the capital

and O&M costs. Second, smaller

systems tend to have higher influent

arsenic concentrations that, on a percapita or per-household basis, require

more expensive treatment methods (e.g.,

a higher percentage removal efficiency)

to comply with an MCL.

Table XIII–6 summarizes the

estimates of total national costs of

compliance with the proposed MCL

options of 3, 5, and 10, and 20 μg/L.

This table is divided into two major

groupings; the first grouping displays

the estimated costs to Community Water

Systems (CWSs) and the second

grouping displays the estimated costs to

Non-Transient Non-Community Water

Systems (NTNCWSs). The State costs

presented in Table XIII–6 were

developed as part of the analyses to

comply with the Unfunded Mandates

Reform Act (UMRA) and also the

Paperwork Reduction Act (PRA).

Additional information on State costs is

provided in Section XIV of this

preamble.

TABLE XIII–6.—SUMMARY OF THE TOTAL ANNUAL NATIONAL COSTS OF COMPLIANCE WITH THE PROPOSED ARSENIC

RULE ACROSS MCL OPTIONS

[In 1997 $ millions] 1

Costs CWS NTNCWS

Cost of capital 3 percent 7 percent 3 percent 7 percent

3 μg/L

Treatment ......................................................................................................... 639.2 746.4 * (25.2) * (30.5)

Monitoring, Reporting & Recordkeeping .......................................................... 2.2 2.9 0.95 1.1

State & EPA Administrative Costs .................................................................. 2.2 3.7 1.1 2.2

Total Costs ............................................................................................... 643.6 753.0 * 1.2 (27.3) * 3.3 (33.8)

5 μg/L

Treatment ......................................................................................................... 373.9 436.0 * (14.7) * (17.8)

Monitoring, Reporting & Recordkeeping .......................................................... 1.9 2.7 0.92 1.1

State & EPA Administrative Costs .................................................................. 1.8 3.1 1.0 2.0

Total Costs ............................................................................................... 377.8 441.8 * 1.2 (16.6) * 3.1 (20.9)

10 μg/L

Treatment ......................................................................................................... 160.4 186.7 * (6.1) * (7.4)

Monitoring, Reporting & Recordkeeping .......................................................... 1.8 2.5 0.90 1.1

State & EPA Administrative Costs .................................................................. 1.5 2.6 0.93 1.9

Total Costs ............................................................................................... 163.7 191.8 * 1.8 (7.9) *3.0 (10.3)

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38961

TABLE XIII–6.—SUMMARY OF THE TOTAL ANNUAL NATIONAL COSTS OF COMPLIANCE WITH THE PROPOSED ARSENIC

RULE ACROSS MCL OPTIONS—Continued

[In 1997 $ millions] 1

Costs CWS NTNCWS

Cost of capital 3 percent 7 percent 3 percent 7 percent

20 μg/L

Treatment ......................................................................................................... 58.9 68.3 * (2.1) * (2.6)

Monitoring, Reporting & Recordkeeping .......................................................... 1.7 2.4 2.0 2.3

State & EPA Administrative Costs .................................................................. 1.3 2.3 0.91 1.9

Total Costs ............................................................................................... 61.9 72.9 * 2.9 (5.1) * 4.2 (6.7)

1Totals may not add due to rounding.

* Costs in parentheses include treatment costs if NTNCWS had to comply with the MCL.

D. What Are the Incremental Benefits and Costs?

Table XIII–7 summarizes the incremental benefits and costs associated with arsenic exposure reduction.

TABLE XIII–7.—ESTIMATES OF THE ANNUAL INCREMENTAL RISK REDUCTION, BENEFITS, AND COSTS OF REDUCING

ARSENIC IN DRINKING WATER

[$millions, 1999]

Arsenic level 20 μg/L 10 μg/L 5 μg/L 3 μg/L

Incremental Risk Reduction, Fatal Bladder Cancers Avoided Per Year ......... 1–3 1.3–2.5 1.9–3.9 1.5–1.5

Incremental Risk Reduction, Non-Fatal Bladder Cancers Avoided Per Year 3–9 3.7–6.5 5.1–11.1 4.5–4.5

Annual Incremental Monetized Benefits 1 ........................................................ 7.9–29.8 10–22.3 13.8–37.8 11.9–14.3

Annual Incremental Costs 2 ............................................................................. 63.2 101.7 214 265.7

1The incremental upper bound benefits estimates presented in this table have been adjusted upwards to reflect an 80% mortality rate, which is

a plausible mortality rate for the area of Taiwan during the Chen study. 2 Costs include treatment, monitoring, O&M, and administrative costs to CWSs; monitoring and administrative costs to NTNCWSs and State

costs.

E. What Are the Risks of Arsenic

Exposure to the General Population and

Sensitive Subpopulations?

The SDWA, as amended, includes

specific provisions in section

1412(b)(3)(C)(i)(V) to assess the effects

of the contaminant on the general

population and on groups within the

general population such as children,

pregnant women, the elderly,

individuals with a history of serious

illness, or other subpopulations that are

identified as likely to be at greater risk

of adverse health effects due to exposure

to contaminants in drinking water than

the general population. The NRC Report

concluded that there is insufficient

scientific information to permit separate

cancer risk estimates for potential

subpopulations such as pregnant

women, lactating women, and children

and that factors that influence

sensitivity to or expression of arsenicassociated cancer and noncancer effects

need to be better characterized. Despite

the inconclusive nature of the effects on

subpopulations, EPA is planning to

issue a health advisory for arsenic in

early 2000. See section IV.C of this

preamble for further information on the

health advisory.

F. What Are the Risks Associated With

Co-Occurring Contaminants?

The SDWA, as amended, requires

EPA to take into account the activities

under preceding rules that may have

impacts on future rules. To address this

requirement, EPA analyzed the cooccurrence of arsenic with other

drinking water contaminants (EPA,

1999f). The results of this analysis help

determine the level of overlap in

regulatory requirements (cost of

technology that can remove more than

one contaminant) and also indicate

where specific levels of one

contaminant may interfere with the

treatment technology for another. This

analysis indicates that there is some cooccurrence of arsenic with sulfate, iron,

and radon. Co-occurrence can also

indicate the likelihood for increased, or

in this case, decreased risks due to

arsenic and selenium.

As discussed in section XI.A.5. of the

preamble, animal studies suggest that

selenium reduces the toxicity of arsenic,

and people in Taiwan have much lower

levels of selenium in their blood and

urine than people in China, the U.S.,

and Canada. Deficient selenium intake

is linked to heart problems, and

excessive intake can lead to thick brittle

nails and changes in the nervous

system. The U.S. recommends a daily

dietary intake of 55 μg/day for females

and 70 μg/day for males. The WHO

lower limit of safe ranges are 30 (for

females) and 40 (for males) μg/day

(NRC, 1990). EPA’s study of cooccurrence of arsenic (at 2, 5, 10, 20,

and > 20 μg/L) and selenium above 50

μg/L levels found no significant

correlations between arsenic and

selenium. EPA believes that, in general,

the U.S. population does not experience

selenium toxicity which would be

reduced by the presence of arsenic and

that there is sufficient selenium in the

American diet to reduce the toxicity of

arsenic. The Agency requests data and

comments on whether selenium

decreases arsenic toxicity on a regional

basis. Section V of this preamble

summarizes the results of EPA’s arsenic

co-occurrence analysis.

G. What Are the Uncertainties in the

Analysis?

The models used to estimate arsenicrelated cancer risks, risk reduction, and

monetary benefits take many inputs

which are both uncertain and highly

variable. The benefits estimates that

have been discussed in this preamble

were derived using point estimates of

38962 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

the monetary surrogates for fatal and

non-fatal bladder cancers. The value of

statistical life (VSL) has been

approximated by a single-value estimate

of $5.8 million, and willingness-to-pay

(WTP) to avoid non-fatal bladder cancer

has been modeled as a constant with a

value of $536,000. These are the central

tendency values derived by EPA, based

on studies from the economic literature

and previous regulatory analyses (US

EPA 1997f, Viscusi et al., 1991).

Because the VSL is much larger than the

WTP value, the VSL value dominates

the total monetary benefits calculation.

The studies that have been reviewed

by EPA (US EPA 1997f) have developed

a wide range of VSL values, from

$700,000 to $16.3 million. This implies

that the monetized benefits of reduced

bladder cancer risks could take a wide

range of values, depending upon the

VSL that is chosen.

Additional sources of uncertainty in

this analysis are also found in the NRC

Report. Such uncertainties include the

shape of the dose-response curve, the

contribution of arsenic exposure from

food, and the choice of model when

conducting arsenic risk assessment.

These sources of uncertainties are

discussed in further detail in section XI.

of today’s document.

XIV. Administrative Requirements

A. Executive Order 12866: Regulatory

Planning and Review

Under Executive Order 12866,

‘‘Regulatory Planning and Review’’ (58

FR 51735, October 4, 1993), the Agency

must determine whether the regulatory

action is ‘‘significant’’ and therefore

subject to OMB review and the

requirements of the Executive Order.

The Order defines ‘‘significant

regulatory action’’ as one that is likely

to result in a rule that may:

(1) Have an annual effect on the

economy of $100 million or more or

adversely affect in a material way the

economy, a sector of the economy,

productivity, competition, jobs, the

environment, public health or safety, or

State, local, or tribal governments or

communities;

(2) Create a serious inconsistency or

otherwise interfere with an action taken

or planned by another agency;

(3) Materially alter the budgetary

impact of entitlements, grants, user fees,

or loan programs or the rights and

obligations of recipients thereof; or

(4) Raise novel legal or policy issues

arising out of legal mandates, the

President’s priorities, or the principles

set forth in the Executive Order.

Pursuant to the terms of Executive

Order 12866, it has been determined

that this rule is a ‘‘significant regulatory

action’’. As such, this action was

submitted to OMB for review. Changes

made in response to OMB suggestions or

recommendations will be documented

in the public record.

B. Regulatory Flexibility Act (RFA), as

Amended by the Small Business

Regulatory Enforcement Fairness Act of

1996 (SBREFA), 5 U.S.C. 601 et seq.

1. Overview

The RFA generally requires an agency

to prepare a regulatory flexibility

analysis of any rule subject to notice

and comment rulemaking requirements

under the Administrative Procedure Act

or any other statute unless the Agency

certifies that the rule will not have a

significant economic impact on a

substantial number of small entities.

Small entities include small businesses,

small organizations, and small

governmental jurisdictions.

2. Use of Alternative Small Entity

Definition

The RFA provides default definitions

for each type of small entity. It also

authorizes an agency to use alternative

definitions for each category of small

entity, ‘‘which are appropriate to the

activities of the agency’’ after proposing

the alternative definition(s) in the

Federal Register and taking comment (5

U.S.C. 601(3)–(5)). In addition to the

above, to establish an alternative small

business definition, agencies must

consult with SBA’s Chief Counsel for

Advocacy.

EPA is proposing the Arsenic Rule

which contains provisions which apply

to small PWSs serving fewer than

10,000 persons. This is the cut-off level

specified by Congress in the 1996

Amendments to the Safe Drinking Water

Act for small system flexibility

provisions. Because this definition does

not correspond to the definitions of

‘‘small’’ for small businesses,

governments, and non-profit

organizations, EPA requested comment

on an alternative definition of ‘‘small

entity’’ in the preamble to the proposed

Consumer Confidence Report (CCR)

regulation (63 FR 7605 at 7620,

February 13, 1998, US EPA 1998j).

Comments showed that stakeholders

supported the proposed alternative

definition. EPA also consulted with the

SBA Office of Advocacy on the

definition as it relates to small business

analysis. In the preamble to the final

CCR regulation (63 FR 44511, August

19, 1998, US EPA, 1998e), EPA stated its

intent to establish this alternative

definition for regulatory flexibility

assessments under the RFA for all

drinking water regulations and has thus

used it in this proposed rulemaking.

3. Initial Regulatory Flexibility Analysis

In accordance with section 603 of the

RFA, EPA prepared an initial regulatory

flexibility analysis (IRFA) that examines

the impact of the proposed rule on small

entities along with regulatory

alternatives that could reduce that

impact. The IRFA is available for review

in the docket and is summarized below.

The RFA requires EPA to address the

following when completing an IRFA:

(1) Describe the reasons why action by

the Agency is being considered;

(2) State succinctly the objectives of,

and legal basis for, the proposed rule;

(3) Describe, and where feasible,

estimate the types and number of small

entities to which the proposed rule will

apply;

(4) Describe the projected reporting,

record keeping, and other compliance

requirements of the rule, including an

estimate of the classes of small entities

that will be subject to the requirements

and the type of professional skills

necessary for preparation of reports or

records;

(5) Identify, to the extent practicable,

all relevant Federal rules that may

duplicate, overlap, or conflict with the

proposed rule; and

(6) Describe any significant

alternatives to the proposed rule that

accomplish the stated objectives of

applicable statutes while minimizing

any significant economic impact of the

proposed rule on small entities.

EPA has considered and addressed all

of the previously described

requirements. The following is a

summary of the IRFA. The first and

second requirements are discussed in

section I.A. of this Preamble. The third

and fourth requirements are

summarized as follows. The fifth

requirement is discussed under section

VIII.F. of this Preamble in a subsection

addressing potential interactions

between the arsenic rule and upcoming

and existing rules affecting community

water systems. The sixth requirement,

regulatory alternatives, is detailed in

section XIII.

a. Number of Small Entities Affected.

The number of small entities subject to

today’s rule is shown in Table XIV–1

below.

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38963

TABLE XIV–1.—PROFILE OF THE UNIVERSE OF SMALL WATER SYSTEMS REGULATED UNDER THE ARSENIC RULE

Water system type

System size category

<100 101–500 501–1,000 1,001–3,300 3,301–10,000

Publicly-Owned:

CWS .............................................................................. 1,729 5,795 3,785 6,179 3,649

NCWS ........................................................................... 1,783 3,171 1,182 361 29

Privately-Owned:

CWS .............................................................................. 13,640 11,266 2,124 1,955 654

NCWS ........................................................................... 8,178 4,162 902 411 56

Total Systems:

CWS .............................................................................. 15,369 17,061 5,909 8,134 4,303

NCWS ........................................................................... 9,961 7,333 2,084 772 85

Total ....................................................................... 25,330 24,394 7,993 8,906 4,388

Source: Safe Drinking Water Information System (SDWIS), December 1998 freeze.

b. Reporting, Recordkeeping and

Other Requirements for Small Systems.

The proposed arsenic rule continues to

require small systems to maintain

records and to report arsenic

concentration levels at the point-ofentry to the water system’s distribution

system. Small systems are also required

to provide arsenic information in the

Consumer Confidence Report or other

public notification if the system exceeds

the MCL. Arsenic monitoring and

reporting will be required annually for

surface water (and mixed surface and

ground water systems) or once every

three years for ground water systems,

unless the small system obtains a

monitoring waiver from the State,

demonstrating compliance with the

proposed MCL. Other existing

information and reporting requirements,

such as Consumer Confidence Reports

and public notification requirements,

will be revised to include the lower

arsenic MCL (see sections VII. H. and I.).

As is the case for other contaminants,

required information on system arsenic

levels must be provided by affected

systems and is not considered to be

confidential. The professional skills

necessary for preparing the reports are

the same skill level required by small

systems for current reporting and

monitoring requirements for other

drinking water standards.

The classes of small entities that are

subject to the proposed arsenic rule

include public water systems serving

less than 10,000 people.

4. Small Business Advocacy Review

(SBAR) Panel Recommendations

As required by section 609(b) of the

RFA, as amended by SBREFA, EPA also

conducted outreach to small entities

and convened a Small Business

Advocacy Review Panel to obtain advice

and recommendations of representatives

of the small entities that potentially

would be subject to the rule’s

requirements.

EPA identified 22 representatives of

small entities that were most likely to be

subject to the proposal. In December,

1998, EPA prepared and distributed to

the small entity representatives (SERs)

an outreach document on the arsenic

rule titled ‘‘Information for Small Entity

Representatives Regarding the Arsenic

in Drinking Water Rule’’ (US EPA,

1998g).

On December 18, 1998, EPA held a

small entity conference call from

Washington D.C. to provide a forum for

small entity input on key issues related

to the planned proposal of the arsenic

in drinking water rule. These issues

included, but were not limited to issues

related to the rule development, such as

arsenic health risks, treatment

technologies, analytical methods, and

monitoring. Fifteen SERs from small

water systems participated on the call

from the following States: Alabama,

Arizona, California, Georgia,

Massachusetts, Montana, Nebraska, New

Hampshire, New Jersey, Utah, Virginia,

Washington, and Wisconsin.

Efforts to identify and incorporate

small entity concerns into this

rulemaking culminated with the

convening of a SBAR Panel on March

30, 1999, pursuant to section 609 of

RFA/SBREFA. The four-person Panel

was headed by EPA’s Small Business

Advocacy Chairperson and included the

Director of the Standards and Risk

Management Division within EPA’s

Office of Ground Water and Drinking

Water, the Administrator of the Office of

Information and Regulatory Affairs with

the Office of Management and Budget,

and the Chief Counsel for Advocacy of

the SBA. For a 60-day period starting on

the convening date, the Panel reviewed

technical background information

related to this rulemaking, reviewed

comments provided by the SERs, and

met on several occasions. The Panel also

conducted its own outreach to the SERs

and held a conference call on April 21,

1999 with the SERs to identify issues

and explore alternative approaches for

accomplishing environmental

protection goals while minimizing

impacts to small entities. Consistent

with the RFA/SBREFA requirements,

the Panel evaluated the assembled

materials and small-entity comments on

issues related to the elements of the

IRFA. A copy of the June 4, 1999 Panel

report is included in the docket for this

proposed rule (US EPA, 1999c).

Today’s notice incorporates all of the

recommendations on which the Panel

reached consensus, except for a number

of recommendations on information to

include in small system guidance. The

small system guidance materials will be

provided before or soon after the final

rule is published in the Federal

Register. EPA is committed to

addressing the following Panel

recommendations regarding guidance

for small systems: highlight the various

waste disposal options and the

necessary technical and procedural

steps for small CWSs to follow in

exploring these alternatives; provide

specific recommendations and technical

information relative to the use of POU

devices; provide guidance to State and

local authorities on waste disposal

issues relative to the use of these

devices; and provide information to

assist in making treatment decisions to

address multiple contaminants in the

most cost-effective manner. The Panel

also recommended that EPA provide

guidance identifying cost-effective

treatment trains for ground water

systems that need to treat for both

arsenic and radon in the proposed rule.

However, treatment trains cannot be

accurately identified until after the

radon and arsenic standards are

finalized because these standards would

affect which treatment technologies are

appropriate. Since the co-occurrence of

38964 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

arsenic and radon seems to be

statistically significant in only two EPA

regions, the impact from this cooccurring pair is not significant on a

national level. However, for the regions

which are impacted, there is the

potential that aeration treatment

technology that may be used to mitigate

radon may also help to mitigate arsenic.

Aeration technology can oxidize the

soluble form of arsenic to the insoluble

form. This would reduce the cost of

arsenic mitigation by making it easier to

remove arsenic. EPA will address this

recommendation further in the small

system guidance materials.

The following is a summary of the rest

of the Panel recommendations and

EPA’s response to these

recommendations, by subject area:

Treatment Technologies, Waste

Disposal, and Cost Estimates: The Panel

recommended the following: further

develop the preliminary treatment and

waste disposal cost estimates; fully

consider these costs when identifying

affordable compliance technologies for

all system size categories; and provide

information to small water systems on

possible options for complying with the

MCL, in addition to installing any listed

compliance technologies.

In response to these

recommendations, the treatment section

of the preamble (see section VIII.A.) and

the Treatment and Cost document (US

EPA, 1999i) describe the development

of final cost estimates for treatment and

waste disposal, including the request for

comment on its projected household

costs; how EPA identified the affordable

compliance technologies, including the

consideration of cost (section VIII.B.);

and information has been added to the

treatment section about options for

complying with the MCL other than

installing compliance technologies,

such as selecting to regionalize (see

section VIII.B.).

Regarding POU devices, the Panel

recommended the following: continue

to promote the use of POU devices as

alternative treatment options for very

small systems where appropriate;

account for all costs, including costs

that may not routinely be explicitly

calculated; and consider liability issues

from POU/POE devices when evaluating

their appropriateness as compliance

technologies; and investigate waste

disposal issues with POE devices.

In response to these

recommendations, the treatment section

of the preamble: includes an expanded

description regarding available POU

compliance treatment technologies and

conditions under which POU treatment

may be appropriate for very small

systems (see section VIII.D.); describes

the components which contribute to the

POU cost estimates (see section VIII.D.);

and clarifies that water systems will be

responsible for POU operation and

maintenance to prevent liability issues

from customers maintaining equipment

themselves (see section VIII.D.). In

addition, EPA does not recommend

reverse osmosis as a POE treatment

technology due to the evaluation of

corrosion control issues (see section

VIII.D.).

Relevance of Other Drinking Water

Regulations: The Panel recommended

the following: include discussion of the

co-occurrence of arsenic and radon in

the proposed rule for arsenic; take

possible interactions among treatments

for different contaminants into account

in costing compliance technologies and

determining whether they are nationally

affordable for small systems; and

encourage systems to be forwardlooking and test for the multiple

contaminants to determine if and how

they would be affected by the upcoming

rules.

In response, the co-occurrence section

of the preamble includes a discussion

on the co-occurrence analysis of radon

and arsenic (see section V.H.), and the

treatment section of the preamble has

been expanded to describe the

relationship of treatment for arsenic

with other drinking water rules and how

this issue was taken into account in cost

estimates (see section VIII.F.). The

preamble encourages systems to

consider other upcoming rules when

making future plans on monitoring or

treatment (see section VIII.E.).

Small Systems Variance Technologies

and National Affordability Criteria: The

Panel recommended the following:

include a discussion of the issues

surrounding appropriate adjustment of

its national affordability criteria to

account for new regulatory

requirements; consider revising its

approach to national affordability

criteria to address the concern that the

current cumulative approach for

adjusting the baseline household water

bills is based on chronological order

rather than risk, to the extent allowed by

statutory and regulatory requirements;

and examine the data in the 1995

Community Water Supply Survey to

determine if in-place treatment

baselines can be linked with the current

annual water bill baseline in each of the

size categories for the proposed rule.

In response to these recommendation,

the treatment section of the preamble

(VIII.C.) includes an expanded

discussion about the national

affordability criteria and adjusting it to

account for new regulations;

information and rationale have been

added to explain the national

affordability approach (see section

VIII.C.). The 1995 Community Water

System Survey (US EPA, 1997g) does

not provide sufficient data to link inplace treatment baselines with annual

water bill baselines.

Monitoring and Arsenic Species: The

Panel recommended that EPA consider

allowing States to use recent

compliance monitoring data to satisfy

initial sampling requirements or to

obtain a waiver and that EPA continue

to explore whether or not to make a

regulatory distinction between organic

and inorganic arsenic based on

compliance costs and other

considerations. In response, the

monitoring section of the preamble and

the proposed regulatory language

describe the allowance of monitoring

data that meet analytical requirements

and have reporting limits sufficiently

below the revised MCL and collected

after 1990. The MCL section of the

preamble contains information and

rationale to support EPA’s decision to

base the MCL on total arsenic (see

section XI).

Considerations in setting the MCL:

The Panel recommended the following:

in performing its obligations under

SDWA, take cognizance of the scientific

findings, the large scientific

uncertainties, the large potential costs

(including treatment and waste disposal

costs), and the fact that this standard is

scheduled for review in the future; give

full consideration to the provisions of

the Executive Order 12866 and to the

option of exercising the new statutory

authority under SDWA sections

1412(b)(4)(C) and 1412(b)(6)(A) in the

development of the arsenic rule; and

fully consider all of the ‘‘risk

management’’ components of its

rulemaking effort to ensure that the

financial and other impacts on small

entities are factored into its decisionmaking processes. The Panel also

recommended that EPA take into

account both quantifiable and nonquantifiable costs and benefits of the

standard and the needs of sensitive subpopulations, and give due consideration

to the impact of the rule upon small

systems.

In response to all these

recommendations, EPA describes in

detail the factors that were considered

in setting in the MCL and provides the

rationale for this selection (see section

XI).

Applicability of proposal: The Panel

recommended that EPA carefully

consider the appropriateness of

extending the scope of the rule to NonTransient, Non-Community Water

Systems (NTNCWSs). In response, the

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38965

9Costed as proposed, using the 3 percent and 7

percent discount rate cost-of-capital values in Table

X–8, in 1999 $ with NTNCWS monitoring and

reporting, but not required to comply with the MCL.

If NTNCWS were to comply with the MCL, their

treatment costs would bring the annualized cost to

$394.4 million.

10Source: table XII–6, in 1997 $.

11Source: Table X–7.

proposed MCL for arsenic does not

apply to NTNCWSs and the MCL

section of the preamble describes the

basis for this decision, including the

incremental costs and benefits

attributable to coverage of these water

systems (see section XI.C.).

Other Issues: The Panel recommended

that EPA encourage small systems to

discuss their infrastructure needs for

complying with the arsenic rule with

their primacy agency to determine their

eligibility for DWSRF loans, and if

eligible, to ask for assistance in applying

for the loans. In response, the UMRA

section XIV.C. has been expanded to

discuss funding options for small

systems, and guidance will be written to

encourage systems to be proactive in

communicating with their primacy

agency.

Regarding health effects, the Panel

recommended the following: Further

evaluate the Utah study and its

relationship to the studies on which the

NRC report was based and give it

appropriate weight in the risk

assessment for the proposed arsenic

standard; and examine the NRC

recommendations in the light of the

uncertainties associated with the

report’s recommendations, and any new

data that may not have been considered

in the NRC report. In response to these

recommendations, the benefits and MCL

sections (sections X and XI) describe the

quantitative and non-quantitative

benefits evaluation and use of research

data.

We invite comments on all aspects of

the proposal and its impacts on small

entities.

C. Unfunded Mandates Reform Act

(UMRA)

Title II of the Unfunded Mandates

Reform Act of 1995 (UMRA), Public

Law 104–4, establishes requirements for

Federal agencies to assess the effects of

their regulatory actions on State, local,

and tribal governments and the private

sector. Under UMRA section 202, EPA

generally must prepare a written

statement, including a cost-benefit

analysis, for proposed and final rules

with ‘‘Federal mandates’’ that may

result in expenditures to State, local,

and tribal governments, in the aggregate,

or to the private sector, of $100 million

or more in any one year. Before

promulgating an EPA rule, for which a

written statement is needed, section 205

of the UMRA generally requires EPA to

identify and consider a reasonable

number of regulatory alternatives and

adopt the least costly, most costeffective or least burdensome alternative

that achieves the objectives of the rule.

The provisions of section 205 do not

apply when they are inconsistent with

applicable law. Moreover, section 205

allows EPA to adopt an alternative other

than the least costly, most cost-effective

or least burdensome alternative if the

Administrator publishes with the final

rule an explanation on why that

alternative was not adopted.

Before EPA establishes any regulatory

requirements that may significantly or

uniquely affect small governments,

including tribal governments, it must

have developed, under section 203 of

the UMRA, a small government agency

plan. The plan must provide for

notifying potentially affected small

governments, enabling officials of

affected small governments to have

meaningful and timely input in the

development of EPA regulatory

proposals with significant Federal

intergovernmental mandates and

informing, educating, and advising

small governments on compliance with

the regulatory requirements.

1. Summary of UMRA Requirements

EPA has determined that this rule

contains a Federal mandate that may

result in expenditures of $100 million or

more for State, local, and Tribal

governments, in the aggregate, and the

private sector in any one year.

Accordingly, EPA has prepared, under

section 202 of the UMRA, a written

statement addressing the following

areas:

(1) Authorizing legislation;

(2) cost-benefit analysis including an

analysis of the extent to which the costs

to State, local, and tribal governments

will be paid for by the Federal

government;

(3) estimates of future compliance

costs and disproportionate budgetary

effects;

(4) macro-economic effects; and

(5) a summary of EPA’s consultation

with State, local, and tribal

governments, a summary of their

concerns, and a summary of EPA’s

evaluation of their concerns.

A summary of this analysis follows

and a more detailed description is

presented in EPA’s Regulatory Impact

Analysis (RIA) of the Arsenic Rule (US

EPA, 2000e) which is included in the

docket for this proposed rulemaking.

a. Authorizing legislation. Today’s

proposed rule is proposed pursuant to

section 1412(b)(13) of the 1996

amendments to the SDWA which

requires EPA to propose and promulgate

a national primary drinking water

regulation for arsenic, establishes a

statutory deadline of January 1, 2000, to

propose this rule, and establishes a

statutory deadline of January 1, 2001, to

promulgate this rule.

b. Cost-benefit analysis. Section XIII.

of this Preamble, describing the

Regulatory Impact Analysis (RIA) and

Health Risk Reduction and Cost

Analysis (HRRCA) for arsenic, contains

a detailed cost-benefit analysis in

support of the arsenic rule. Today’s

proposed rule is expected to have a total

annualized cost of approximately $379

to 445 million.9 This total annualized

cost includes the total annual

administrative costs of State, local, and

tribal governments, in aggregate, less

than 1% of the cost, and total annual

treatment (CWS only, as proposed),

monitoring, reporting, and record

keeping impacts on public water

systems, in aggregate, of approximately

$376.7 to 439.8 million.10 Treatment

costs estimates are presented in Sections

IX.D. and E. of this Preamble, and

administrative costs are discussed in

section 9 of the RIA (US EPA, 2000e).

The RIA includes both qualitative and

monetized benefits for improvements in

health and safety. EPA estimates the

proposed arsenic rule will have annual

monetized benefits for bladder cancer of

approximately $43.6 to 104.2 million if

the MCL were to be set at 3 μg/L, $31.7

to 89.9 million if set at 5 μg/L, $17.9 to

52 million if set at 10 μg/L, and $7.9 to

29.8 million if set at 20μg/L (EPA also

estimates possible lung cancer benefits

based on the ‘‘What If’’ scenario of $47–

448 million at 3 μg/L, $35–384 million

at 5 μg/L, $19.6–224 million at 10 μg/

L, and $8.8–128 million at 20 μg/L.).11

The monetized health benefits of

reducing arsenic exposures in drinking

water are attributable to the reduced

incidence of fatal and non-fatal bladder

cancers. Under baseline assumptions

(no control of arsenic exposure <50 μg/

L), 10–17 fatal bladder cancers and 29–

48 non-fatal bladder cancers per year are

associated with arsenic exposures

through CWSs. At a arsenic level of 3

μg/L, an estimated 5.7 to 10.9 fatal

bladder cancers and 22 to 42 non-fatal

bladder cancers per year are prevented.

At a level of 5 μg/L, an estimated 4 to

9 fatal bladder cancers and 16 to 36 nonfatal bladder cancers per year are

prevented. At a level 10 μg/L, 2 to 6 fatal

and 9 to 21 non-fatal bladder cancers

per year are prevented. At a level 20 μg/

L, 1 to 3 fatal and 3 to 9 non-fatal

bladder cancers per year are prevented.

38966 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

In addition to quantifiable benefits,

EPA has identified several potential

non-quantifiable benefits associated

with reducing arsenic exposures in

drinking water. These potential benefits

are difficult to quantify because of the

uncertainty surrounding their

estimation. Non-quantifiable benefits

may include any peace-of-mind benefits

specific to reduction of arsenic risks that

may not be adequately captured in the

Value of Statistical Life (VSL) estimate.

State, local and Tribal governments

will incur a range of administrative

costs with the MCL options in

complying with the arsenic rule.

Administrative costs associated with

water mitigation can include costs

associated with program management,

inspections, and enforcement activities.

EPA estimates the total annual costs of

administrative activities for compliance

with the MCL to be approximately $2.8

million.

c. Financial Assistance. Various

Federal programs exist to provide

financial assistance to State, local, and

tribal governments to administer and

comply with this and other drinking

water rules. The Federal government

provides funding to States that have a

primary enforcement responsibility for

their drinking water programs through

the Public Water Systems Supervision

(PWSS) Grants program. Additional

funding is available from other

programs administered either by EPA or

other Federal agencies. These include

the Drinking Water State Revolving

Fund (DWSRF) and Housing and Urban

Development’s Community

Development Block Grant Program. For

example, the SDWA authorizes the

Administrator of the EPA to award

capitalization grants to States, which in

turn can provide low cost loans and

other types of assistance to eligible

public water systems. The DWSRF

assists public water systems with

financing the costs of infrastructure

needed to achieve or maintain

compliance with SDWA requirements.

Each State will have considerable

flexibility to determine the design of its

program and to direct funding toward

its most pressing compliance and public

health protection needs. States may

also, on a matching basis, use up to ten

percent of their DWSRF allotments for

each fiscal year to assist in running the

State drinking water program.

Under PWSS Program Assistance

Grants, the Administrator may make

grants to States to carry out public water

system supervision programs. States

may use these funds to develop primacy

programs. States may ‘‘contract’’ with

other State agencies to assist in the

development or implementation of their

primacy program. However, States may

not use program assistance grant funds

to contract with regulated entities (i.e.,

water systems). PWSS Grants may be

used by States to set-up and administer

a State program which includes such

activities as: public education, testing,

training, technical assistance,

developing and administering a

remediation grant and loan or incentive

program (excludes the actual grant or

loan funds), or other regulatory or nonregulatory measures.

d. Estimates of future compliance

costs and disproportionate budgetary

effects. To meet the requirement in

section 202 of the UMRA, EPA analyzed

future compliance costs and possible

disproportionate budgetary effects of the

MCL options. The Agency believes that

the cost estimates, indicated previously

and discussed in more detail in Section

XIII.B of today’s Preamble accurately

characterize future compliance costs of

the proposed rule.

With regard to the disproportionate

impacts, EPA considered available data

sources in analyzing the

disproportionate impacts upon

geographic or social segments of the

nation or industry. No rationale for

disproportionate impacts by geography

were identified. EPA will prepare a

small entity compliance guide, a

monitoring/analytical manual, and a

small systems technology manual that

will assist the public and private sector.

To fully consider the potential

disproportionate impacts of this

proposed rule, this analysis also

developed three other measures:

(1) Reviewing the impacts on small

versus large systems;

(2) reviewing the costs to public

versus private water systems; and

(3) reviewing the household costs for

the proposed rule.

The first measure, the national

impacts on small versus large systems,

is shown in Section IX, Table IX–12,

Total Annual Costs per Household.

Small systems are defined as those

systems serving 10,000 people or less

and large systems are those systems that

serve more than 10,000 people. The

higher compliance costs to small

systems is primarily due to the greater

number of small systems as opposed to

large systems (i.e., there are 39,420

small systems versus 1,443 large

systems).

The second measure of

disproportionate impacts evaluated is

the relative total costs to public versus

private water systems, by size. Table

XIV–2 presents the total annualized

costs for public and private systems by

system size category for the 3 μg/L, 5 μg/

L, 10 μg/L, and 20 μg/L arsenic levels.

The costs are comparable for public and

private systems across system sizes for

all options. This pattern may be due in

large part to the limited number of

treatment options assumed to be

available to either public or private

systems to remove arsenic.

TABLE XIV–2.—AVERAGE ANNUAL COST PER CWS BY OWNERSHIP

System size

Treatment and monitoring

costs

Total cost

Public Private All systems

MCL = 3 μg/L

<100 ......................................................................................................................................................... $9,475 $7,354 $7,559

101–500 ................................................................................................................................................... 25,228 18,570 20,588

501–1,000 ................................................................................................................................................ 34,688 31,645 33,474

1,001–3,300 ............................................................................................................................................. 60,929 51,097 58,189

3,301–10,000 ........................................................................................................................................... 135,573 111,396 131,197

10,001–1,000,000 .................................................................................................................................... 578,591 547,969 573,423

>1,000,000 ............................................................................................................................................... 3,885,713 .................... 3,885,713

MCL = 5 μg/L

<100 ......................................................................................................................................................... 9,720 7,212 7,450

101–500 ................................................................................................................................................... 24,560 18,223 20,198

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38967

TABLE XIV–2.—AVERAGE ANNUAL COST PER CWS BY OWNERSHIP—Continued

System size

Treatment and monitoring

costs

Total cost

Public Private All systems

501–1,000 ................................................................................................................................................ 34,124 30,697 32,778

1,001–3,300 ............................................................................................................................................. 57,277 48,198 54,666

3,301–10,000 ........................................................................................................................................... 124,552 102,005 120,399

10,001–1,000,000 .................................................................................................................................... 518,647 459,930 508,640

>1,000,000 ............................................................................................................................................... 2,669,474 .................... 2,669,474

MCL = 10 μg/L

<100 ......................................................................................................................................................... 9,453 7,135 7,350

101–500 ................................................................................................................................................... 23,584 17,675 19,551

501–1,000 ................................................................................................................................................ 32,271 29,160 31,048

1,001–3,300 ............................................................................................................................................. 53,357 44,785 50,921

3,301–10,000 ........................................................................................................................................... 113,338 91,244 109,278

10,001–1,000,000 .................................................................................................................................... 458,340 415,520 450,835

>1,000,000 ............................................................................................................................................... 1,395,498 .................... 1,395,498

MCL = 20 μg/L

<100 ......................................................................................................................................................... 9,121 6,950 7,157

101–500 ................................................................................................................................................... 22,778 16,954 18,738

501–1,000 ................................................................................................................................................ 30,493 27,668 29,376

1,001–3,300 ............................................................................................................................................. 48,399 41,625 46,501

3,301–10,000 ........................................................................................................................................... 99,872 79,128 95,983

10,001–1,000,000 .................................................................................................................................... 394,742 334,737 384,868

>1,000,000 ............................................................................................................................................... 921,121 .................... 921,121

* Costs were calculated at a commercial interest rate and include system treatment, monitoring, and administrative costs; note that systems

serving over 1 million people are public surface water systems.

The third measure, household costs,

can also be used to gauge the impact of

a regulation and to determine whether

there are disproportionately high

impacts in particular segments of the

population. A detailed analysis of

household cost impacts by system size

is presented in the RIA (US EPA 2000e).

The costs for households served by

public and private water systems are

presented in Table XIV–3. As expected,

cost per household increases as system

size decreases. Cost per household is

higher for households served by smaller

systems than larger systems for two

reasons. First, smaller systems serve far

fewer households than larger systems

and, consequently, each household

must bear a greater percentage share of

the system’s costs. Second, smaller

systems tend to have higher influent

arsenic concentrations that, on a percapita or per-household basis, require

more expensive treatment methods to

achieve the target arsenic level.

There is a moderate difference in

annual cost per household for the 3 μg/

L, 5 μg/L, 10 μg/L, and 20 μg/L levels

for each size category. However, the

costs per household are higher for

private systems than for public systems.

For public systems, the cost per

household ranges from $24.73 to

$341.78 per year at 5 μg/L and from

$22.03 to $329.17 per year at 10 μg/L.

For private systems, the ranges are

$21.91 to $369.21 per year, and $19.06

to $363.08 per year, respectively.

TABLE XIV–3.—AVERAGE COMPLIANCE COSTS PER HOUSEHOLD FOR CWSS EXCEEDING MCLS

System size

Groundwater Surface water

Public Private Public Private

MCL = 3 μg/L

<100 ................................................................................................................................. $338.44 $374.86 328.94 $385.61

101–500 ........................................................................................................................... 218.59 285.61 135.98 183.96

501–1,000 ........................................................................................................................ 108.63 112.60 45.44 46.72

1,001–3,300 ..................................................................................................................... 62.17 83.24 21.13 27.91

3,301–10,000 ................................................................................................................... 44.67 62.96 18.34 22.94

10,001–1,000,000 ............................................................................................................ 31.29 31.29 26.49 22.81

>1,000,000 ....................................................................................................................... .................... .................... 2.70 ....................

MCL = 5 μg/L

<100 ................................................................................................................................. 341.78 369.21 323.48 330.05

101–500 ........................................................................................................................... 213.11 280.76 135.22 182.65

501–1,000 ........................................................................................................................ 106.00 108.40 44.86 46.35

1,001–3,300 ..................................................................................................................... 58.31 77.54 20.07 26.57

3,301–10,000 ................................................................................................................... 40.60 57.25 16.89 21.54

10,001–1,000,000 ............................................................................................................ 28.12 28.63 24.73 21.91

38968 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

TABLE XIV–3.—AVERAGE COMPLIANCE COSTS PER HOUSEHOLD FOR CWSS EXCEEDING MCLS—Continued

System size

Groundwater Surface water

Public Private Public Private

>1,000,000 ....................................................................................................................... .................... .................... 1.73 ....................

MCL = 10 μg/L

<100 ................................................................................................................................. 329.17 363.09 317.80 325.64

101–500 ........................................................................................................................... 203.40 273.04 132.74 180.88

501–1,000 ........................................................................................................................ 99.45 102.19 42.98 44.48

1,001–3,300 ..................................................................................................................... 53.70 71.97 18.62 25.49

3,301–10,000 ................................................................................................................... 36.30 50.41 14.68 18.55

10,001–1,000,000 ............................................................................................................ 24.09 24.47 22.03 19.06

>1,000,000 ....................................................................................................................... .................... .................... 0.89 ....................

MCL = 20 μg/L

<100 ................................................................................................................................. 320.13 352.42 310.11 324.84

101–500 ........................................................................................................................... 195.99 262.01 132.68 179.93

501–1,000 ........................................................................................................................ 93.27 96.63 42.26 44.04

1,001–3,300 ..................................................................................................................... 48.03 66.12 18.20 24.87

3,301–10,000 ................................................................................................................... 31.38 44.14 13.35 17.53

10,001–1,000,000 ............................................................................................................ 20.27 20.39 19.96 ....................

>1,000,000 ....................................................................................................................... .................... .................... 0.55 ....................

*Costs to households were calculated at a commercial interest rate and include system treatment, monitoring, and administrative costs; note

that systems serving over 1 million people are public surface water systems.

TABLE XIV–4.—AVERAGE COMPLIANCE COSTS PER HOUSEHOLD FOR CWSS EXCEEDING MCLS AS A PERCENT OF

MEDIAN HOUSEHOLD INCOME

System size

Groundwater Surface water

Public Private Public Private

MCL = 3 μg/L

<100 ................................................................................................................................. 0.85 0.95 0.83 0.85

101–500 ........................................................................................................................... 0.55 0.72 0.34 0.46

501–1,000 ........................................................................................................................ 0.27 0.28 0.11 0.12

1,001–3,300 ..................................................................................................................... 0.16 0.21 0.05 0.07

3,301–10,000 ................................................................................................................... 0.11 0.16 0.05 0.06

10,001–1,000,000 ............................................................................................................ 0.08 0.08 0.07 0.06

>1,000,0000 ..................................................................................................................... .................... .................... 0.01 ....................

MCL = 5 μg/L

<100 ................................................................................................................................. 0.86 0.93 0.82 0.83

101–500 ........................................................................................................................... 0.54 0.71 0.34 0.46

501–1,000 ........................................................................................................................ 0.27 0.27 0.11 0.12

1,001–3,300 ..................................................................................................................... 0.15 0.20 0.05 0.07

3,301–10,000 ................................................................................................................... 0.10 0.14 0.04 0.05

10,001–1,000,000 ............................................................................................................ 0.07 0.07 0.06 0.06

>1,000,0000 ..................................................................................................................... .................... .................... 0.00 ....................

MCL = 10 μg/L

<100 ................................................................................................................................. 0.83 0.92 0.80 0.82

101–500 ........................................................................................................................... 0.51 0.69 0.33 0.46

501–1,000 ........................................................................................................................ 0.25 0.26 0.11 0.11

1,001–3,300 ..................................................................................................................... 0.14 0.18 0.05 0.06

3,301–10,000 ................................................................................................................... 0.09 0.13 0.04 0.05

10,001–1,000,000 ............................................................................................................ 0.06 0.06 0.06 0.05

>1,000,0000 ..................................................................................................................... .................... .................... 0.00 ....................

MCL = 20 μg/L

<100 ................................................................................................................................. 0.81 0.89 0.78 0.82

101–500 ........................................................................................................................... 0.49 0.66 0.33 0.45

501–1,000 ........................................................................................................................ 0.24 0.24 0.11 0.11

1,001–3,300 ..................................................................................................................... 0.12 0.17 0.05 0.06

3,301–10,000 ................................................................................................................... 0.08 0.11 0.03 0.04

10,001–1,000,000 ............................................................................................................ 0.05 0.05 0.05 0.00

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38969

TABLE XIV–4.—AVERAGE COMPLIANCE COSTS PER HOUSEHOLD FOR CWSS EXCEEDING MCLS AS A PERCENT OF

MEDIAN HOUSEHOLD INCOME—Continued

System size

Groundwater Surface water

Public Private Public Private

>1,000,0000 ..................................................................................................................... .................... .................... 0.00 ....................

* Costs to household were calculated at a commercial interest rate and include system treatment, monitoring, and administrative costs; median

household income in May 1999 was $39,648 from the 1998 annual median household income from the Census.

To further evaluate the impacts of

these household costs, the costs per

household were compared to median

household income data for each systemsize category. The result of this

calculation, presented in Table XIV–4

for public and private systems, indicate

a household’s likely share of

incremental costs in terms of its

household income. For all system sizes,

household costs as a percentage of

median household income are less than

one percent for households served by

either public or private systems. Similar

to the cost per household results on

which they are based, household

impacts exhibit little variability across

arsenic levels.

e. Macroeconomic effects. As required

under UMRA § 202, EPA is required to

estimate the potential macro-economic

effects of the regulation. These types of

effects include those on productivity,

economic growth, full employment,

creation of productive jobs, and

international competitiveness. Macroeconomic effects tend to be measurable

in nationwide econometric models only

if the economic impact of the regulation

reaches 0.25 percent to 0.5 percent of

Gross Domestic Product (GDP). In 1998,

real GDP was $7,552 billion so a rule

would have to cost at least $18 billion

annually to have a measurable effect. A

regulation with a smaller aggregate

effect is unlikely to have any

measurable impact unless it is highly

focused on a particular geographic

region or economic sector. The macroeconomic effects on the national

economy from the arsenic rule should

be negligible based on the fact that,

assuming 100 percent compliance with

an MCL, the total annual costs are

approximately $756 million at the 3 μg/

L level, $445 million at the 5 μg/L level,

about $195 million at the 10 μg/L level,

and at the 20 μg/L level, about $77

million (at a 7 percent discount rate),

and the costs are not expected to be

highly focused on a particular

geographic region or industry sector.

f. Summary of EPA’s consultation

with State, local, and tribal governments

and their concerns. Under UMRA

section 204, EPA is to provide a

summary of its consultation with

elected representatives (or their

designated authorized employees) of

affected State, local, and Tribal

governments in this rulemaking. EPA

initiated consultations with

governmental entities and the private

sector affected by this rulemaking

through various means. This included

five stakeholder meetings announced in

the Federal Register and open to any

one interested in attending in person or

by phone, and presentations at meetings

of the American Water Works

Association (AWWA), the Association

of State Drinking Water Administrators

(ASDWA), the Association of California

Water Agencies (ACWA), and the

Association of Metropolitan Water

Agencies (AMWA). Participants in

EPA’s stakeholder meetings also

included representatives from the

National Rural Water Association,

AMWA, ASDWA, AWWA, ACWA,

Rural Community Assistance Program,

State departments of environmental

protection, State health departments,

State drinking water programs, and a

Tribe. EPA also made presentations at

Tribal meetings in Nevada, Alaska, and

California. To address the proposed

rule’s impact on small entities, the

Agency consulted with representatives

of small water systems and convened a

Small Business Advocacy Review Panel

in accordance with the Regulatory

Flexibility Act (RFA) as amended by the

Small Business Regulatory Enforcement

Fairness Act (SBREFA). Two of the

small entity representatives were

elected officials from local governments.

EPA also invited State drinking water

program representatives to participate in

a number of workgroup meetings. In

addition to these consultations, EPA

participated in and gave presentations at

AWWA’s Technical Workgroup for

Arsenic. State public health department

and drinking water program

representatives, drinking water districts,

and ASDWA participated in the

Technical Workgroup meetings. Finally

EPA presented the benefits analysis to

State and Tribal health and

environmental agencies.

The public docket for this proposed

rulemaking contains meeting summaries

for EPA’s five stakeholder meetings on

arsenic in drinking water, written

comments received by the Agency, and

provides details about the nature of

State, local, and Tribal government’s

concerns. A summary of State, local,

and Tribal government concerns on this

proposed rulemaking is in the next

section.

In order to inform and involve Tribal

governments in the rulemaking process,

EPA staff attended the 16th Annual

Consumer Conference of the National

Indian Health Board on October 6–8,

1998 in Anchorage, Alaska. Over nine

hundred attendees representing Tribes

from across the country were in

attendance. During the conference, EPA

conducted two workshops for meeting

participants. The objectives of the

workshops were to present an overview

of EPA’s drinking water program, solicit

comments on key issues of potential

interest in upcoming drinking water

regulations, and to solicit advice in

identifying an effective consultative

process with Tribes for the future.

EPA, in conjunction with the Inter

Tribal Council of Arizona (ITCA), also

convened a Tribal consultation meeting

on February 24–25, 1999, in Las Vegas,

Nevada to discuss ways to involve

Tribal representatives, both Tribal

council members and tribal water utility

operators, in the stakeholder process.

Approximately twenty-five

representatives from a diverse group of

Tribes attended the two-day meeting.

Meeting participants included

representatives from the following

Tribes: Cherokee Nation, Nezperce

Tribe, Jicarilla Apache Tribe, Blackfeet

Tribe, Seminole Tribe of Florida, Hopi

Tribe, Cheyenne River Sioux Tribe,

Menominee Indian Tribe, Tulalip

Tribes, Mississippi Band of Choctaw

Indians, Narragansett Indian Tribe, and

Yakama Nation.

The major meeting objectives were to:

(1) identify key issues of concern to

Tribal representatives;

(2) solicit input on issues concerning

current OGWDW regulatory efforts;

(3) solicit input and information that

should be included in support of future

drinking water regulations; and

38970 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

(4) provide an effective format for

Tribal involvement in EPA’s regulatory

development process.

EPA staff also provided an overview

on the forthcoming arsenic rule at the

meeting. The presentation included the

health concerns associated with arsenic,

EPA’s current position on arsenic in

drinking water, the definition of an

MCL, an explanation of the difference

between point-of-use and point-of-entry

treatment devices, and specific issues

for Tribes. The following questions were

posed to the Tribal representatives to

begin discussion on arsenic in drinking

water:

(1) What are the current arsenic levels

in your water systems?

(2) What are Tribal water systems

affordability issues in regard to arsenic?

(3) Does your Tribe use well water,

river water or lake water?

(4) Purchase water from another

drinking water utility?

The summary for the February 24–25,

1999 meeting was sent to all 565

Federally recognized Tribes in the

United States.

EPA also conducted a series of

workshops at the Annual Conference of

the National Tribal Environmental

Council which was held on May 18–20,

1999 in Eureka, California.

Representatives from over 50 Tribes

attended all, or part, of these sessions.

The objectives of the workshops were to

provide an overview of forthcoming

EPA regulations affecting water systems;

discuss changes to operator certification

requirements; discuss funding for Tribal

water systems; and to discuss

innovative approaches to regulatory cost

reduction. Meeting summaries for EPA’s

Tribal consultations are available in the

public docket for this proposed

rulemaking.

g. Nature of State, local, and Tribal

government concerns and how EPA

addressed these concerns. State and

local governments raised several

concerns, including the high costs of the

rule to small systems; the burden of

revising the State primacy program; the

high degree of uncertainty associated

with the benefits; the high costs of

including Non-Transient NonCommunity Water Systems (NTNCWSs).

EPA modified regulations governing the

revision of State primacy in order to

decrease the burden of the new arsenic

regulation in response to State concerns

that EPA minimize paperwork and

documentation of existing programs that

would manage the arsenic regulation.

Section XI. asks for comment on

alternate MCL options, based partly on

the high costs of the rule for small

systems and uncertainty associated with

the risks.

Tribal representatives were generally

supportive of regulations which would

ensure a high level of water quality, but

raised concerns over funding for

regulations. With regard to the

forthcoming proposed arsenic rule,

many Tribal representatives saw the

health benefits as highly desirable, but

felt that unless additional funds were

made available, implementing the

regulation would be difficult for many

Tribes.

EPA understands the State, local, and

tribal government concerns with the

above issues. The Agency believes the

options for small systems, proposed for

public comment in this rulemaking, will

address stakeholder concerns pertaining

to small systems and will help to reduce

the financial burden to these systems.

Small systems compliance technologies

and associated costs were listed in

section VIII.E. Regionalization, the

process by which a small system can

connect with another system and

purchase water, is a non-treatment

option that could be considered for

small systems. The costs for

regionalization by system size are

presented as Treatment Train #1 in

Table VIII–3 of section VIII.B. Sections

XII.C address tribal SRF and grant

funding.

Non-Transient Non-Community Water

Systems (NTNCWSs) are only required

to monitor and report exceedances of

the MCL. A detailed discussion of the

exposure to arsenic in NTNCWSs is

shown in section V.F. of this Preamble.

EPA has conducted a preliminary

analysis on exposure and risks to

NTNCWSs and is soliciting public

comment on this preliminary analysis.

An analysis of the potential benefits and

costs of arsenic in drinking water for

NTNCWSs is summarized in the

preamble and included in the docket for

this proposed rulemaking (US EPA

2000e).

The Agency is basing this regulation

on the risks to the general population

and is not excluding any particular

segments of the population. For a more

complete discussion on the risks of

arsenic in drinking water and air, see

section II.C. of this Preamble.

h. Regulatory Alternatives

Considered. As required under section

205 of the UMRA, EPA considered

several regulatory alternatives in

developing an MCL for arsenic in

drinking water. In preparation for this

consideration, the Regulatory Impact

Analysis and Health Risk Reduction and

Cost Analysis (HRRCA) for Arsenic

evaluated arsenic levels of 3 μg/L, 5 μg/

L, 10 μg/L, and 20 μg/L.

The Regulatory Impact Analysis and

HRRCA also evaluated national costs

and benefits of States choosing to

reduce arsenic exposure in drinking

water. For further discussion on the

regulatory alternatives considered in

this proposed rulemaking, see section

XIII. of this Preamble. EPA examined a

range of regulatory alternatives that

could be employed to achieve the

objectives of this rule and chose what it

believes is the least burdensome such

alternative. The regulatory approach

embodied in this rule includes a

proposed MCL that relies on the use of

the Administrator’s discretionary

authority under section 1412(b)(6) of the

SDWA to set a less stringent level than

the feasible level. The exercise of these

authorities in this manner is expected to

reduce overall burden on regulated

entitities (as compared to the burden of

a more stringent level) but still

maximize health risk reduction. (See

section XI.A for a more complete

discussion of the rationale for the

exercise of these authorities.) In terms of

coverage of the rule, we are proposing

that only CWSs be fully covered by the

rule, driven, in part by consideration of

the burden associated with not covering

NTNCWSs in view of the minimal

health risk reduction that would be

achieved. The proposed approach is

also based upon an analysis and listing

of least cost treatment alternatives

(including use of point of use treatment

devices) that are collectively expected to

reduce regulatory burden. Finally,

today’s proposal includes an approach

to monitoring and reporting that

involves a framework that provides for

reduced regulatory burden where

arsenic levels are low. Also, see EPA’s

Regulatory Impact Analysis for Arsenic

(US EPA 2000e).

2. Impacts on Small Governments

In developing this rule, EPA

consulted with small governments

pursuant to section 203 of the UMRA to

address impacts of regulatory

requirements in the rule that might

significantly or uniquely affect small

governments. In preparation for the

proposed arsenic rule, EPA conducted

analysis on small government impacts

and included small government officials

or their designated representatives in

the rule making process. EPA conducted

stakeholder meetings on the

development of the arsenic rule which

gave a variety of stakeholders, including

small governments, the opportunity for

timely and meaningful participation in

the regulatory development process.

Groups such as the National Association

of Towns and Townships, the National

League of Cities, and the National

Association of Counties participated in

the proposed rulemaking process.

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38971

Through such participation and

exchange, EPA notified potentially

affected small governments of

requirements under consideration and

provided officials of affected small

governments with an opportunity to

have meaningful and timely input into

the development of the regulatory

proposal. See section XIV.B.6.a. for a

summary of the Small Business Review

Panel consultations.

In addition, EPA will educate, inform,

and advise small systems, including

those run by small governments, about

the arsenic rule requirements. One of

the most important components of this

process is the Small Entity Compliance

Guide, required by the Small Business

Regulatory Enforcement Fairness Act of

1996 shortly after the rule is

promulgated. This plain-English guide

will explain what actions a small entity

must take to comply with the rule. Also,

the Agency is developing fact sheets

that concisely describe various aspects

and requirements of the arsenic rule.

D. Paperwork Reduction Act (PRA)

The information collection

requirements in this proposed rule have

been submitted for approval to the

Office of Management and Budget

(OMB) under the Paperwork Reduction

Act, 44 U.S.C. 3501 et seq. An

Information Collection Request (ICR)

document has been prepared by EPA

(ICR, No. 1948.01) and a copy may be

obtained from Sandy Farmer by mail at

Collection Strategies Division; U.S.

Environmental Protection Agency

(2822); 1200 Pennsylvania Ave., NW,

Washington, DC 20460, by email at

farmer.sandy@epamail.epa.gov, or by

calling (202) 260–2740. A copy may also

be downloaded off the Internet at http:/

/www.epa.gov/icr.

Two types of information will be

collected under the proposed arsenic

rule. First, information on CWSs and

NTNCWSs and their arsenic levels

reported under 50 μg/L will enable the

States and EPA to evaluate compliance

with the lower MCL. This information,

most of which consists of monitoring

results, corresponds to arsenic

information already collected from

water systems. Arsenic monitoring and

reporting will continue annually for

surface water systems or once every

three years for ground water systems,

unless the MCL is exceeded or a State

grants a waiver (see section VII). Other

existing information and reporting

requirements, such as Consumer

Confidence Reports (US EPA, 1998j) and

the public notification requirements (US

EPA, 2000c), will be amended to reflect

the lower MCL for arsenic. As proposed,

NTNCWSs will not be required to

comply with the MCL because of the

low exposure levels as explained in

section XI.C. However, EPA is requiring

NTNCWSs to report to the State and

public when it exceeds the MCL

through public notification

requirements. As is the case for other

contaminants, required information on

system arsenic levels must be provided

by affected systems and is not

considered to be confidential. EPA

believes the information needs

discussed previously, on compliance

with the MCL programs, are essential to

achieving the arsenic-related health risk

reductions anticipated by EPA under

the proposed rule.

EPA has estimated the burden

associated with the specific record

keeping and reporting requirements of

the proposed rule in an accompanying

Information Collection Request (ICR),

which is available in the public docket

for this proposed rulemaking. Burden

means the total time, effort, or financial

resources expended by persons to

generate, maintain, retain, or disclose or

provide information to or for a Federal

agency. This includes the time needed

to review instructions; develop, acquire,

install, and utilize technology and

systems for the purposes of collecting,

validating, and verifying information,

processing and maintaining

information, and disclosing and

providing information; adjust the

existing procedures to comply with any

previously applicable instructions and

requirements; train personnel to be able

to respond to a collection of

information; search data sources;

complete and review the collection of

information; and transmit or otherwise

disclose the information.

The ICR for the proposed rule covers

the information collection, reporting

and record-keeping requirements for the

three-year period following

promulgation of the Arsenic Rule. There

are several activities that PWSs must

perform in preparation for compliance

with the revised Arsenic Rule in the

first three years. Start-up activities

include reading the final rule to become

familiar with the requirements and

training staff to perform the required

activities. The number of hours required

to perform each activity varies by

system size. The total start-up burden

per system for systems serving less than

10,000 people is estimated to be 24

hours; the total start-up burden per

system for systems serving more than

10,000 people is estimated to be 40

hours. The total hour burden for the

74,607 PWSs (including NTNCWS)

covered by this rule is estimated to be

1,847,784 hours, or an annual average of

615,928 hours. There are no monitoring,

record-keeping, reporting or equipment

costs for PWSs during the first threeyear period. EPA expects States to incur

only nominal information collection,

reporting or record-keeping costs during

the first three years. (For estimates of

the cost of information collection,

reporting and record-keeping over a 20-

year period, see ICR No. 1948.01)

An agency may not conduct or

sponsor, and a person is not required to

respond to, a collection of information

unless it displays a currently valid OMB

control number. The OMB control

numbers for EPA’s regulations are listed

in 40 CFR part 9 and 48 CFR Chapter

15.

Comments are requested on the

Agency’s need for this information, the

accuracy of the provided burden

estimates, and any suggested methods

for minimizing respondent burden,

including through the use of automated

collection techniques. Send comments

on the ICR to the Director, Collection

Strategies Division; U.S. Environmental

Protection Agency (2822); 1200

Pennsylvania Ave., NW, Washington,

DC 20460; and to the Office of

Information and Regulatory Affairs,

Office of Management and Budget, 725

17th St., NW, Washington, DC 20503,

marked ‘‘Attention: Desk Officer for

EPA.’’ Include the ICR number in any

correspondence. Since OMB is required

to make a decision concerning the ICR

between 30 and 60 days after June 22,

2000, a comment to OMB is best assured

of having its full effect if OMB receives

it by July 24, 2000. The final rule will

respond to any OMB or public

comments on the information collection

requirements contained in this proposal.

E. National Technology Transfer and

Advancement Act (NTTAA)

Section 12(d) of the National

Technology Transfer and Advancement

Act of 1995 (NTTAA), (Public Law 104–

113, section 12(d), 15 U.S.C. 272 note),

directs EPA to use voluntary consensus

standards in its regulatory activities

unless to do so would be inconsistent

with applicable law or otherwise

impractical. Voluntary consensus

standards are technical standards (e.g.,

material specifications, test methods,

sampling procedures, business

practices, etc.) that are developed or

adopted by voluntary consensus

standard bodies. The NTTAA directs

EPA to provide to Congress, through

OMB, explanations when the Agency

decides not to use available and

applicable voluntary consensus

standards.

EPA’s process for selecting analytical

methods is consistent with section 12(d)

of the NTTAA. EPA performed a

38972 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

literature search to identify analytical

methods from industry, academia,

voluntary consensus standard bodies

and other parties that could be used to

reliably measure total arsenic in

drinking water at the proposed MCL of

0.005 mg/L. Today’s proposed

rulemaking allows the use of analytical

methods which are described in the

‘‘Annual Book of ASTM Standards’’

(American Society for Testing and

Materials, 1994 and 1996) and in

‘‘Standards for the Examination of

Water and Wastewater’’ (APHA, 1992

and 1995). The four methods published

by these consensus organizations

include SM 3113B, SM 3114B, ASTM

2972–93B and ASTM 2972–93C. These

methods were all approved for arsenic

analysis in previous methods-related

rulemakings for the MCL of 0.050

mg/L. Along with the review of other

analytical methods, EPA also reevaluated these consensus methods for

the new arsenic standard. The Agency

believes these methods will still be

reliable for compliance monitoring at

the proposed MCL of 0.005 mg/L.

Additional information on these

methods are shown in section VI. C. and

F. of today’s preamble. One consensus

method, SM 3120B, will be withdrawn

in today’s rulemaking. As discussed in

section VI.D., SM 3120B will be

withdrawn because the detection limit

for this method is inadequate to reliably

determine the presence of arsenic at the

proposed MCL of 0.005 mg/L.

Although no other methods were

identified from the literature search,

EPA welcomes comments on this aspect

of today’s proposed rulemaking and

specifically invites the public to identify

potentially-applicable voluntary

consensus standards, explain why such

standard should be considered for

inclusion with this regulation, and to

provide the necessary information from

inter-laboratory studies on detection

limits, accuracy, recovery and precision.

F. Executive Order 12898:

Environmental Justice

Executive Order 12898 ‘‘Federal

Actions To Address Environmental

Justice in Minority Populations and

Low-Income Populations,’’ (59 FR 7629,

February 16, 1994) establishes a Federal

policy for incorporating environmental

justice into Federal agency missions by

directing agencies to identify and

address disproportionately high and

adverse human health or environmental

effects of its programs, policies, and

activities on minority and low-income

populations. The Agency has

considered environmental justicerelated issues concerning the potential

impacts of this action and has consulted

with minority and low-income

stakeholders by convening a stakeholder

meeting via video conference

specifically to address environmental

justice issues.

As part of EPA’s responsibilities to

comply with Executive Order 12898, the

Agency held a stakeholder meeting via

video conference on March 12, 1998, to

highlight components of pending

drinking water regulations and how

they may impact sensitive subpopulations, minority populations, and

low-income populations. Topics

discussed included treatment

techniques, costs and benefits, data

quality, health effects, and the

regulatory process. Participants

included national, State, tribal,

municipal, and individual stakeholders.

EPA conducted the meeting by video

conference call between eleven cities.

This meeting was a continuation of

stakeholder meetings that started in

1995 to obtain input on the Agency’s

Drinking Water programs. The major

objectives for the 1998 meeting were:

(1) Solicit ideas from Environmental

Justice (EJ) stakeholders on known

issues concerning current drinking

water regulatory efforts;

(2) Identify key issues of concern to EJ

stakeholders; and

(3) Receive suggestions from EJ

stakeholders concerning ways to

increase representation of EJ

communities in OGWDW regulatory

efforts.

In addition, EPA developed a plainEnglish guide specifically for this

meeting to assist stakeholders in

understanding the multiple and

sometimes complex issues surrounding

drinking water regulations. A meeting

summary for the March 12, 1998

Environmental Justice stakeholders

meeting (US EPA, 1998b) is available in

the public docket for this proposed

rulemaking.

During the presentation of separate

cities’ discussions, several arsenic

issues came up. In Region 6 one

stakeholder thought that test results for

arsenic (discussed in ppb and μg/L)

were hard to understand, and the health

effects appear to be complicated. Region

6 participants had concerns about the

toxic effects on mothers, individuals

with different metabolisms, and

individuals with poor nutrition. One of

the stakeholders expressed a concern

that the government was not protecting

poorer communities against pollution.

In Region 7, one stakeholder lives in an

area that purchases water which has to

be monitored. The area has a shrinking

population that is increasing in age and

immune conditions. Although there are

pesticides in the water and air, it would

not be economically practical to

consolidate to a regional drinking water

system. One member of an Indian tribe

said Tribes tend to have more diabetes

than the rest of the country, and

diabetes seemed to be linked to arsenic

exposure. In Region 8 a stakeholder

wanted affordable or equally protective

treatment options. A Region 8

participant asked for disclosure of

environmental contamination. Region 9

reported some individual monitoring

difficulties. Stakeholders wanted better

access to funding sources. Stakeholders

in Region 9 had concerns about the

immuno-compromised, young children,

and pregnant women. Some

stakeholders wanted standard setting to

address regional needs, include local

governments in the standard setting,

more technical assistance and training,

and more stakeholder involvement.

Tribes and large cities with low income

families may be burdened with more of

the risk.

The Agency considered equity-related

issues concerning the potential impacts

of this action. There is no factual basis

to indicate that minority and low

income communities are more (or less)

exposed to arsenic in drinking water.

The occurrence information suggests

there is no difference between the

percent of systems likely to be impacted

in small communities versus larger

ones. Further, arsenic in drinking water

is primarily natural in origin (rather

than related to contamination events)

and a systematic bias based on

socioeconomic factors would not be

expected to occur. A key issue of

concern is the potential for an uneven

distribution of risk reduction benefits

across water systems and society.

The public is invited to comment on

EPA’s analysis of environmental justice

and, specifically, to recommend

additional methods to address

environmental justice concerns with the

approach for treating arsenic in drinking

water.

G. Executive Order 13045: Protection of

Children from Environmental Health

Risks and Safety Risks

Executive Order 13045, ‘‘Protection of

Children from Environmental Health

Risks and Safety Risks,’’ (62 FR 19885

April 23, 1997) applies to any rule that:

(1) is determined to be ‘‘economically

significant’’ as defined under Executive

Order 12866, and (2) concerns an

environmental health or safety risk that

EPA has reason to believe may have a

disproportionate effect on children. If

the regulatory action meets both criteria,

the Agency must evaluate the

environmental health or safety effects of

the planned rule on children, and

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38973

explain why the planned regulation is

preferable to other potentially effective

and reasonably feasible alternatives

considered by the Agency.

This proposed rule is not subject to

the Executive Order because the Agency

does not have reason to believe the

environmental health risks or safety

risks addressed by this action present a

disproportionate risk to children.

Nonetheless, we have evaluated the

environmental health or safety effects of

arsenic in drinking water on children.

The results of this evaluation are

contained in section III.F.5. of this

Preamble. Copies of the documents used

to evaluate the environmental health or

safety effects of arsenic in drinking

water on children have been placed in

the public docket for this proposed

rulemaking.

The public is invited to submit or

identify peer-reviewed studies and data,

of which EPA may not be aware, that

assessed results of early life exposure to

arsenic via ingestion.

H. Executive Order 13132: Federalism

Executive Order 13132, entitled

‘‘Federalism’’ (64 FR 43255, August 10,

1999), requires EPA to develop an

accountable process to ensure

‘‘meaningful and timely input by State

and local officials in the development of

regulatory policies that have federalism

implications.’’ ‘‘Policies that have

federalism implications’’ is defined in

the Executive Order to include

regulations that have ‘‘substantial direct

effects on the States, on the relationship

between the national government and

the States, or on the distribution of

power and responsibilities among the

various levels of government.’’

Under section 6 of Executive Order

13132, EPA may not issue a regulation

that has federalism implications, that

imposes substantial direct compliance

costs, and that is not required by statute,

unless the Federal government provides

the funds necessary to pay the direct

compliance costs incurred by State and

local governments, or EPA consults with

State and local officials early in the

process of developing the proposed

regulation. EPA also may not issue a

regulation that has federalism

implications and that preempts State

law, unless the Agency consults with

State and local officials early in the

process of developing the proposed

regulation.

If EPA complies by consulting,

Executive Order 13132 requires EPA to

provide to the Office of Management

and Budget (OMB), in a separately

identified section of the preamble to the

rule, a federalism summary impact

statement (FSIS). The FSIS must include

a description of the extent of EPA’s

prior consultation with State and local

officials, a summary of the nature of

their concerns and the agency’s position

supporting the need to issue the

regulation, and a statement of the extent

to which the concerns of State and local

officials have been met. Also, when EPA

transmits a draft final rule with

federalism implications to OMB for

review pursuant to Executive Order

12866, EPA must include a certification

from the agency’s Federalism Official

stating that EPA has met the

requirements of Executive Order 13132

in a meaningful and timely manner.

EPA has concluded that this proposed

rule will have federalism implications.

This rule will impose substantial direct

compliance costs on State and local

governments, and the Federal

government will not provide the funds

necessary to pay those costs.

Accordingly, EPA provides the

following FSIS as required by section

6(b) of Executive Order 13132.

EPA consulted with State and local

officials early in the process of

developing the proposed regulation to

permit them to have meaningful and

timely input into its development.

Summaries of the meetings have been

included int public record for this

proposed rulemaking. EPA consulted

extensively with State, local, and tribal

governments. For example, we held four

public stakeholder meetings in

Washington, D.C. (two meetings); San

Antonio, Texas; and Monterey,

California. Invitations to stakeholder

meetings were extended to the National

Association of Counties, The National

Governors’ Association, the National

Association of Towns and Townships,

the National League of Cities, and the

National Conference of State Legislators.

In addition, several elected officials

were part of the Small Business

Advocacy Review Panel convened by

EPA (as required by section 609(b) of

the Regulatory Flexibility Act).

Consultation has not ended, however,

but will be an on-going transactional

process. EPA officials presented a

summary of the rule to the National

Governor’s Association in a meeting on

May 24, 2000. In addition, we

scheduled a one-day stakeholders’

meeting for the trade associations that

represent elected officials on May 30,

2000 to discuss and solicit comment on

this and other upcoming contaminant

rules. EPA will continue to seek input

from its State and local government

partners.

Several key issues were raised by

stakeholders regarding the arsenic rule

provision, many of which were related

to reducing burden and maintaining

flexibility. The Office of Water was able

to reduce burden and increase flexibility

in a number of areas in response to

these comments. More specifically,

elected officials expressed overall

concerns about: (1) Factors considered

in setting of the MCL and (2) the

treatment technologies, their associated

costs and waste disposal costs. Specific

issues regarding the setting of the MCL

included:

• The treatment costs associated with

a lower drinking water standard;

• Concerns about affordability for

lower income areas;

• Asking the Agency to delay setting

a standard below 25 μg/L until the

development of affordable technologies;

and

• A lack of evidence for health effects

data below 50 μg/L.

Specific concerns regarding the

treatment technologies, their associated

costs and waste disposal costs included:

• The difficulty of using oxidation/

filtration for arsenic removal when

concentrations are <25 μg/L (even after

the addition of iron salts and pH

adjustment);

• The waste disposal costs created

from the use of ion exchange;

• The more intensive need for

operator oversight and the amount of

sludge generated using coagulation

filtration and lime softening at a high

pH;

• The difficulty in finding and the

expense associated with activated

alumina;

• The expense associated with

reverse osmosis, nano-filtration and preoxidation.

The Agency responded to these

concerns in several ways. We are very

sensitive to the potential costs of

treatment for a lower drinking water

standard and have examined an array of

treatment options (especially those that

are most appropriate for small systems)

in order to identify the least cost,

affordable options that systems may use

to comply with a new standard. We

therefore do not believe that it is

necessary to delay promulgating a rule

with an MCL below 25 μg/L pending

identification of such technologies, as

one of the comments suggests. We have

also included higher MCL options than

the proposed MCL in the preamble for

comment, due in large part to concerns

expressed by elected officials and other

stakeholders about the treatment costs

associated with a low MCL. These

issues are discussed in more detail in

the sections VIII. (treatment) and XI.

(regarding choice of the MCL). We also

share the concerns of elected officials in

connection with the affordability of a

new rule for lower income areas and

38974 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

have identified special programs and

avenues that may be pursued to provide

relief for such areas (see section VIII.C.).

In response to the comment that there

is a lack of evidence for health effects

below 50 μg/L, we note that the National

Academy of Sciences’’ National

Research Council has categorically

determined, based on their review of the

most recent data and information

concerning the health effects of arsenic,

that the current standard of 50 μg/L is

not protective and should be revised

downward as soon as possible (NRC,

1999). This topic is discussed in more

detail in section III.

In response to concerns about specific

treatment technologies, their associated

costs and waste disposal costs, EPA

identifies several treatment technologies

in section VIII. Section VIII. A.

identifies the BATs for arsenic removal

and section VIII.B. identifies

technologies which are considered

affordable. The Agency agrees with the

statement that oxidation/filtration is not

an appropriate technology to treat

arsenic to low levels. For this reason, it

is not considered a BAT. The Agency

also agrees that wastes are created using

ion exchange. Section VIII. addresses

the use of brine recycling in reducing

wastes and waste disposal costs. In

addition, regionalization or finding a

new water source (section VIII.) are

alternative non-treatment options to

consider to avoid treatment and the

costs and disposal issues associated

with treatment. The Agency agrees with

the concern that coagulation/filtration is

more operator intensive but this

technology and pH modifications are

only considered if this treatment

process is already in place. In regards to

the amount of sludge produced, the

additional amount of sludge generated

due to the removal of arsenic is minor.

The Agency disagrees that activated

alumina is expensive and difficult to

find. As shown in Table VIII–3,

activated alumina is one of the cheaper

treatment technologies. The Agency

agrees that reverse osmosis, nanofiltration and the need for pre-oxidation

are expensive treatment options. In

these cases, a PWS should consider one

of the more affordable treatment options

shown in section VIII.B.

I. Executive Order 13084: Consultation

and Coordination with Indian Tribal

Governments

Under Executive Order 13084,

‘‘Consultation and Coordination with

Indian Tribal Governments,’’ 63 FR

27655 (May 19, 1998) EPA may not

issue a regulation that is not required by

statute, that significantly or uniquely

affects the communities of Indian Tribal

governments, and that imposes

substantial direct compliance costs on

those communities, unless the Federal

government provides the funds

necessary to pay the direct compliance

costs incurred by the Tribal

governments, or EPA consults with

those governments. If EPA complies by

consulting, Executive Order 13084

requires EPA to provide the Office of

Management and Budget, in a separately

identified section of the preamble to the

rule, a description of the extent of EPA’s

prior consultation with representatives

of affected Tribal governments, a

summary of the nature of their concerns,

and a statement supporting the need to

issue the regulation. In addition,

Executive Order 13084 requires EPA to

develop an effective process permitting

elected officials and other

representatives of Indian Tribal

governments ‘‘to provide meaningful

and timely input in the development of

regulatory policies on matters that

significantly or uniquely affect their

communities.’’

EPA has concluded that this rule may

significantly affect communities of

Indian Tribal governments. It will also

impose substantial direct compliance

costs on such communities, and the

Federal government will not provide the

funds necessary to pay the direct costs

incurred by the Tribal governments in

complying with the rule. In developing

this rule, EPA consulted with

representatives of Tribal governments

pursuant to Executive Order 13084.

Summaries of the meetings have been

included in the public docket for this

proposed rulemaking. EPA’s

consultation, the nature of the

governments’ concerns, and EPA’s

position supporting the need for this

rule are discussed in sections XIV.C.1.f.

and g. of this Preamble.

J. Request for Comments on Use of Plain

Language

Executive Order 12866 and the

President’s memorandum of June 1,

1998, require each agency to write all

rules in plain language. We invite your

comments on how to make this

proposed rule easier to understand. For

example:

• Have we organized the material to

suit your needs?

• Are the requirements in the rule

clearly stated?

• Does the rule contain technical

language or jargon that isn’t clear?

• Would a different format (grouping

and order of sections, use of headings,

paragraphing) make the rule easier to

understand?

• Would more (but shorter) sections

be better?

• Could we improve clarity by adding

tables, lists, or diagrams?

• What else could we do to make the

rule easier to understand?

XV. References

The following references are referred

to in this notice and are included in the

public docket together with other

correspondence and information. The

public docket is available as described

at the beginning of this notice. All

public comments received on the

proposal are included in the public

docket.

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Water Regulations; Volatile Synthetic

Organic Chemicals; Proposed Rule. Federal

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1989, from SAB to EPA. Ad Hoc Work

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US EPA. 1991a. National Primary Drinking

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Regulations Implementation; National

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US EPA. 1991b. Arsenic IRIS File; Arsenic,

Inorganic. February 1991. Used for 1992

National Toxics Rule, December 22, 1992,

57 FR 60848.

US EPA. 1991c. Arsenic Research

Recommendations memorandum dated

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Chair of the Arsenic Research

Recommendation Workgroup, Health

Effects Research Laboratory.

US EPA. 1992a. Science Advisory Board

Report: Review of the Office of Research

and Development’s Arsenic Research

Recommendations. Washington, DC.

Science Advisory Board. EPA–SAB–DWC–

92–018. May 1992.

US EPA. 1992b. National Primary Drinking

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Chemicals and Inorganic Chemicals; Final

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31776. July 17, 1992.

US EPA. 1992c. Water Quality Standards;

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1992.

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and T. Stevens. The Inorganic Chemical

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Residuals. EPA/600/SR–92–117,

Cincinnati.

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Criteria Document on Inorganic Arsenic.

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1993.

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US EPA. 1994a. EPA Method 200.15,

Determination of Metals and Trace

Elements in Water By Ultrasonic

Nebulization Inductively Coupled PlasmaAtomic Emission Spectrometry. Methods

for the Determination of Metals in

Environmental Samples—Supplement I,

Rev 1.2. EPA/600/R–94–111. May 1994.

US EPA. 1994b. Methods for the

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Samples—Supplement I. EPA/600/R–94–

111, NTIS PB 94–184942.

US EPA. 1994c. National Primary and

Secondary Drinking Water Regulations:

Analytical Methods for Regulated Drinking

Water Contaminants; Final Rule. Federal

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US EPA. 1994d. SW–846 Method 6020,

Inductively Coupled Plasma-Mass

Spectrometry. Test Methods for Evaluating

Solid Waste: Physical/Chemical Methods.

Third Edition, September 1994 Update II.

US EPA. 1994e. SW–846 Method 7060A,

Arsenic (Atomic Absorption, Furnace

Technique). Test Methods for Evaluating

Solid Waste: Physical/Chemical Methods.

Third Edition, September 1994 Update II.

US EPA. 1994f. SW–846 Method 7062,

Antimony and Arsenic (Atomic

Absorption, Borohydride Reduction). Test

Methods for Evaluating Solid Waste,

Physical/Chemical Methods. Third Edition,

September 1994 Update II.

US EPA. 1995. Science Advisory Board

Report: Review of Issues Related to the

Regulation of Arsenic in Drinking Water.

Washington, DC. Science Advisory Board.

EPA–SAB–DWC–95–015. July 19, 1995.

US EPA. 1996a. EPA Method 1632, Inorganic

Arsenic In Water by Hydride Generation

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Carcinogenic Risk Assessment; Notice.

Federal Register. Vol 61, No. 79, p. 17960.

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US EPA. 1996c. Performance Evaluation

Studies Supporting Administration of the

Clean Water Act and the Safe Drinking

Water Act. Federal Register. Vol. 61, No.

139, p. 37464. July 18, 1996.

US EPA. 1996d. SW–846 Method 7063,

Arsenic in Aqueous Samples and Extracts

by Anodic Stripping Voltammetry (ASV).

Test Methods for Evaluating Solid Wastes,

Physical/Chemical Methods. Third Edition,

December 1996, Update III.

US EPA. 1996e. Investigator-Initiated Grants

on Health Effects of Arsenic. Federal

Register. Vol 61, No. 236, p. 64739.

December 6, 1996.

US EPA. 1997a. Manual for the Certification

of Laboratories Analyzing Drinking Water.

EPA 815/B–97/001.

US EPA. 1997b. March 1994 Workshop on

Developing an Epidemiology Research

Strategy for Arsenic in Drinking Water.

Prepared for EPA’s National Health and

Environmental Effects Research Laboratory

by SRA Technologies. April 14, 1997.

US EPA 1997c. Performance Evaluation

Studies Supporting Administration of the

Clean Water Act and the Safe Drinking

Water Act. Federal Register. Vol. 62, No.

113, p. 32112. June 12, 1997.

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US EPA. 1997d. National Center for

Environmental Assessment. Report on the

Expert Panel on Arsenic Carcinogenicity:

Review and Workshop. Lexington, MA.

Prepared by the Eastern Research Group

under contract to US EPA. August 1997.

US EPA. 1997e. Performance Based

Measurement System. Federal Register.

Vol. 62, No. 193, p. 52098. October 6, 1997.

US EPA. 1997f. Benefits and Costs of the

Clean Air Act. 1970–1990. Clean Air Act

§ 812. Report Prepared for U.S. Congress by

US EPA Office of Air and Radiation.

Chapter 6. October. EPA 410–R–97–002.

US EPA. 1997g. Community Water System

Survey, Volume I: Overview and Volume

II: Detailed Survey Result Tables and

Methodology Report. EPA 815–R–97–001a

and EPA 815–R–97–001b. January, 1997.

US EPA. 1998a. Research Plan for Arsenic in

Drinking Water. Office of Research and

Development, National Center for

Environmental Assessment. EPA/600/R–

98/042. www.epa.gov/ORD/WebPubs/final/

arsenic.pdf February 1998.

US EPA. 1998b. Environmental Justice

Stakeholders Meeting March 12, 1998

Meeting Summary.

US EPA. 1998c. Locating and Estimating Air

Emissions From Sources of Arsenic and

Arsenic Compounds. Research Triangle

Park, NC. Office of Air Quality Planning

and Standards. EPA–454–R–98–013. June

1998.

US EPA 1998d. National Primary Drinking

Water Regulations: Analytical Methods for

Regulated Drinking Water Contaminants;

Final and Proposed Rule. Federal Register.

Vol. 63, No. 171, p. 47097. September 3,

1998.

US EPA. 1998e. National Primary Drinking

Water Regulations: Consumer Confidence

Reports. Final Rule. Federal Register. Vol.

63, No. 160, p. 44512. August 19, 1998.

US EPA. 1998f. Variance Technology

Findings for Contaminants Regulated

Before 1996. Office of Water. EPA 815–R–

98–003. September 1998.

US EPA. 1998g. Information for Small Entity

Representatives Regarding the Arsenic in

Drinking Water Rule. December 3, 1998.

US EPA. 1998h. Announcement of Small

System Compliance Technology Lists for

Existing National Primary Drinking Water

Regulations and Findings Concerning

Variance Technologies. Notice of Lists of

Technologies and Upcoming Release of

Guidance and Supporting Documents.

Federal Register. Vol. 63, No. 153, p.

42032 at 43045. August 6, 1998.

US EPA. 1998i. Removal of the Prohibition

on the Use of Point of Use Devices for

Compliance with National Primary

Drinking Water Regulation, Federal

Register notice (63 FR 31934). June 11,

1998.

US EPA. 1998j. National Primary Drinking

Water Regulations: Consumer Confidence

Reports. Proposed Rule. Federal Register.

Vol. 63, No. p. 7605. February 13, 1998.

US EPA. 1999a. Cost of Illness Handbook.

Office of Pollution Prevention and Toxics.

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September, 1999.

US EPA. 1999b. National Primary Drinking

Water Regulations: Public Notification

Rule, Proposed Rule. Federal Register. Vol.

64, No. 92, p. 25964. May 13, 1999.

US EPA. 1999c. Report of the Small Business

Advocacy Review Panel on EPA’s Planned

Proposal of the National Primary Drinking

Water Regulation for Arsenic. Cover memo

to the Administrator and the report. June

4, 1999.

US EPA. 1999d. Decision Tree for the

Arsenic Rulemaking Process. Washington,

DC. Office of Ground Water and Drinking

Water. 404 pp. July 1999.

US EPA. 1999e. Geometries and

Characteristics of Public Water Systems.

Prepared by Science Applications

International Corporation under contract

with EPA OGWDW. August 15, 1999.

US EPA. 1999f. Co-Occurrence of Drinking

Water Contaminants. Prepared by Science

Applications International Corporation

under contract 68–C6–0059 for EPA

OGWDW. September 30, 1999.

US EPA. 1999g. Small Systems Compliance

Technology List for the Arsenic Rule.

Prepared by ICI under contract 68–C6–

0039. November, 1999.

US EPA. 1999h. Small Systems Compliance

Technology List for the Arsenic Rule.

Prepared by ICI under contract 68–C6–

0039. November, 1999.

US EPA. 1999i. Technologies and Costs for

the Removal of Arsenic from Drinking

Water. Washington, DC. Office of Ground

Water and Drinking Water. 386 pp.

November, 1999.

US EPA. 1999j. National Primary Drinking

Water Regulations: Analytical Methods for

Chemical and Microbiological

Contaminants and Revisions to Laboratory

Certification Requirements; Final Rule.

Federal Register. Vol. 64, No. 230, p.

67450. December 1, 1999.

US EPA. 1999k. Arsenic Risk

Characterization, Part 1. Prepared by ISSI

Consulting Group, Inc. for EPA Office of

Water, Office of Standards and

Technology. December 22, 1999.

US EPA. 1999l. Analytical Methods Support

Document for Arsenic in Drinking Water.

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International Corporation under contract

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Management Division. December, 1999.

US EPA. 1999m. Drinking Water Baseline

Handbook. Prepared by International

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US EPA. 1999n. National Primary Drinking

Water Regulations: Radon-222, Proposed

Rule. Federal Register. Vol. 64, No. 211, p.

59246. EPA 815–z–99–006. November 2,

1999.

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Regulatory Compliance Costs for the 25

Largest Public Water Systems (With

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1996 Continuing Survey of Food Intakes by

Individuals. Office of Water, Office of

Standards and Technology. EPA–822–00–

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May 2000.

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List of Subjects

40 CFR Part 141

Environmental protection, Chemicals,

Indians—lands, Intergovernmental

relations, Reporting and recordkeeping

requirements, Water supply.

40 CFR Part 142

Environmental protection,

Administrative practice and procedure,

Chemicals, Indians—lands, Reporting

and recordkeeping requirements, Water

supply.

Dated: May 24, 2000.

Carol M. Browner,

Administrator.

For reasons set out in the preamble,

the Environmental Protection Agency

proposes to amend 40 CFR parts 141

and 142 as follows:

PART 141—NATIONAL PRIMARY

DRINKING WATER REGULATIONS

1. The authority citation for part 141

continues to read as follows:

Authority: 42 U.S.C. 300f, 300g–1, 300g–2,

300g–3, 300g–4, 300g–5, 300g–6, 300j–4,

300j–9, and 300j–11.

Subpart A—General

§ 141.2 [Amended]

2. Section 141.2 is amended by

revising the definition heading for

‘‘Point-of-entry treatment device’’ to

read ‘‘Point-of-entry treatment device

(POE)’’ and revising the definition

heading for ‘‘Point-of-use treatment

device’’ to read ‘‘Point-of-use treatment

device (POU)’’.

3. Section 141.6 is amended by:

a. In paragraph (a) by revising the

reference ‘‘(a) through (i)’’ to read ‘‘(a)

through (k)’’.

b. Revising paragraph (c).

c. Adding paragraphs (j) and (k).

The revisions and additions read as

follows:

§ 141.6 Effective dates.

* * * * *

(c) The regulations set forth in

§§ 141.11(d); 141.21(a), (c) and (i);

141.22(a) and (e); 141.23(a)(3) and (a)(4);

141.23(f); 141.24(e) and (f); 141.25(e);

141.27(a); 141.28(a) and (b); 141.31(a),

(d) and (e); 141.32(b)(3); and 141.32(d)

shall take effect immediately upon

promulgation.

* * * * *

(j) The arsenic MCL listed in § 141.62

is effective [THREE YEARS AFTER

PUBLICATION DATE OF THE FINAL

RULE]. Compliance with the arsenic

MCL listed in § 141.62 is required for

community water systems serving

10,000 people or less on [DATE 5

YEARS AFTER PUBLICATION DATE

OF THE FINAL RULE], and for all other

community water systems on [DATE 3

YEARS AFTER PUBLICATION DATE

OF THE FINAL RULE] for

§§ 141.23(a)(4), (a)(4)(i), (a)(5), (c), (f)(1),

(g), (i), (k)(1), (k)(2), and (k)(3)(ii);

141.62(b)(16) and (c); 141.203, and

revisions to arsenic in Appendices A

and B of Subpart Q of this part for the

public notification rule. However, the

reporting date for the arsenic MCL listed

in Appendix A of Subpart O of this part

of the consumer confidence rule

requirements and the arsenic reporting

requirements in § 141.154(b) are

[THIRTY DAYS AFTER PUBLICATION

DATE OF THE FINAL RULE]. Nontransient non-community water systems

will be subject to the sampling,

monitoring, and reporting requirements

of §§ 141.23(a), 141.23(c)(1)–(6),

141.23(f), 141.23(g), 141.23(k), 141.203,

and 141.209 for arsenic exceeding the

MCL listed in § 141.62 [DATE 3 YEARS

AFTER PUBLICATION DATE OF THE

FINAL RULE].

(k) Compliance with §§ 141.23(c)(9),

141.24(f)(15)(ii), 141.24(f)(22) and

141.24(h)(20) regulations for inorganics

and organics other than total

trihalomethanes and sampling

frequencies for new systems and new

sources of water is required on [DATE

3 YEARS AFTER PUBLICATION DATE

OF THE FINAL RULE].

Subpart B—[Amended]

4. Section 141.11 is amended by

revising the second sentence of

paragraph (a) and revising paragraph (b)

to read as follows:

§ 141.11 Maximum contaminant levels for

inorganic chemicals.

(a) * * * The analyses and

determination of compliance with the

0.05 milligrams per liter maximum

contaminant level for arsenic use the

requirements of § 141.23(l).

(b) The maximum contaminant level

for arsenic is 0.05 milligrams per liter

for community water systems serving

10,000 people or less until [DATE 5

YEARS AFTER PUBLICATION DATE

OF THE FINAL RULE], and for all other

community water systems until [DATE

3 YEARS AFTER PUBLICATION DATE

OF THE FINAL RULE]. Non-transient

non-community water systems will be

subject to sampling, monitoring and

reporting requirements for arsenic as of

[DATE 3 YEARS AFTER PUBLICATION

DATE OF THE FINAL RULE]; however,

they will not be subject to

§§ 141.23(c)(7) and (8) and

141.62(b)(16).

* * * * *

Subpart C—[Amended]

5. Section 141.23 is amended by:

a. Adding a new entry for ‘‘Arsenic’’

in alphabetical order to the table in

paragraph (a)(4)(i) and footnotes 6 and

7.

b. Adding ‘‘arsenic,’’ before ‘‘barium,’’

in paragraph (a)(5).

c. Adding ‘‘arsenic,’’ before ‘‘barium,’’

in paragraph (c) introductory text.

d. Adding paragraph (c)(9).

e. Revising the words ‘‘asbestos,

antimony,’’ to read ‘‘antimony, arsenic,

asbestos,’’ in paragraph (f)(1).

f. Adding ‘‘arsenic,’’ before

‘‘asbestos,’’ in paragraph (i)(1).

g. Adding one sentence at the end of

paragraph (i)(1).

h. Revising paragraph (i)(2).

i. Add paragraph (i)(5).

j. Revise ‘‘arsenic’’ entry in the table

in paragraph (k)(1).

k. Adding ‘‘arsenic,’’ before

‘‘asbestos,’’ in paragraph (k)(2)

introductory text.

l. In the table to paragraph (k)(2) by

adding in alphabetical order a new entry

for ‘‘Arsenic’’.

m. Adding ‘‘arsenic,’’ before

‘‘asbestos,’’ in paragraph (k)(3)

introductory text.

n. Adding in alphabetical order a new

entry for ‘‘Arsenic’’ to the table in

paragraph (k)(3)(ii).

The revisions and additions read as

follows:

§ 141.23 Inorganic chemical sampling and

analytical requirements.

(a) * * *

(4) * * *

(i) * * *

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38979

DETECTION LIMITS FOR INORGANIC CONTAMINANTS

Contaminant MCL (mg/l) Methodology Detection

Limit (mg/l)

*******

Arsenic ................................................ 0.005 Atomic Absorption; Furnace ........................................................................... 0.001

Atomic Absorption; Platform–Stabilized Temperature ................................... 6 0.0005

Atomic Absorption; Gaseous Hydride ............................................................ 0.001

ICP-Mass Spectrometry ................................................................................. 7 0.0014

*******

*******

6The MDL reported for EPA Method 200.9 (Atomic Absorption; Platform—Stabilized Temperature) was determined using a 2x concentration

step during sample digestion. The MDL determined for samples analyzed using direct analysis (i.e., no sample digestion) will be higher. Using

multiple depositions, EPA 200.9 is capable of obtaining a MDL of 0.0001 mg/L. 7 Using selective ion monitoring, EPA Method 200.8 (ICP–MS) is capable of obtaining a MDL of 0.0001 mg/L.

* * * * *

(c) * * *

(9) All new systems or systems that

use a new source of water that begin

operation after [EFFECTIVE DATE OF

THE FINAL RULE] must demonstrate

compliance with the MCL within a

period of time specified by the State.

The system must also comply with the

initial sampling frequencies specified by

the State to ensure a system can

demonstrate compliance with the MCL.

Routine and increased monitoring

frequencies shall be conducted in

accordance with the requirements in

this section.

* * * * *

(i) * * *

(1) * * * If a system fails to collect

the required number of samples,

compliance (average concentration) will

be based on the total number of samples

collected.

(2) For systems which are monitoring

annually, or less frequently, the system

is out of compliance with the maximum

contaminant levels for antimony,

arsenic, asbestos, barium, beryllium,

cadmium, chromium, cyanide, fluoride,

mercury, nickel, selenium or thallium if

the level of a contaminant is greater

than the MCL. If confirmation samples

are required by the State, the

determination of compliance will be

based on the annual average of the

initial MCL exceedance and any Staterequired confirmation samples. If a

system fails to collect the required

number of samples, compliance (average

concentration) will be based on the total

number of samples collected.

* * * * *

(5) Arsenic sampling results will be

reported to the nearest 0.001 mg/L.

* * * * *

(k) * * *

(1) * * *

Contaminant and methodology 13 EPA ASTM 3 SM 4 Other

*******

Arsenic 14:

ICP—Mass Spectrometry ......................................................................................... 2 200.8

Atomic Absorption; Platform ..................................................................................... 2 200.9

Atomic Absorption; Furnace ..................................................................................... ................ D–2972–93C 3113B.

Hydride Atomic Absorption ....................................................................................... ................ D–2972–93B 3114B.

*******

2 ‘‘Methods for the Determination of Metals in Environmental Samples—Supplement I’’, EPA/600/R–94/111, May 1994. Available at NTIS,

PB95–125472. 3Annual Book of ASTM Standards,1994 and 1996, Vols. 11.01 and 11.02, American Society for Testing and Materials. The previous versions

of D1688–95A, D1688–95C (copper), D3559–95D (lead), D1293–95 (pH), D1125–91A (conductivity) and D859–94 (silica) are also approved.

These previous versions D1688–90A, C; D3559–90D, D1293–84, D1125–91A and D859–88, respectively are located in the Annual Book of

ASTM Standards,1994, Vols. 11.01. Copies may be obtained from the American Society for Testing and Materials, 100 Barr Harbor Drive, West

Conshohocken, PA 19428. 4 18th and 19th editions of Standard Methods for the Examination of Water and Wastewater,1992 and 1995, respectively, American Public

Health Association; either edition may be used. Copies may be obtained from the American Public Health Association, 1015 Fifteenth Street NW,

Washington, DC 20005.

* * * * * **

13Because MDLs reported in EPA Methods 200.7 and 200.9 were determined using a 2X preconcentration step during sample digestion,

MDLs determined when samples are analyzed by direct analysis (i.e.,no sample digestion) will be higher. For direct analysis of cadmium and arsenic by Method 200.7, and arsenic by Method 3120 B sample preconcentration using pneumatic nebulization may be required to achieve lower

detection limits. Preconcentration may also be required for direct analysis of antimony, lead, and thallium by Method 200.9; antimony and lead by

Method 3113 B; and lead by Method D3559–90D unless multiple in-furnace depositions are made. 14 If ultrasonic nebulization is used in the determination of arsenic by Methods 200.7, 200.8, or SM 3120 B, the arsenic must be in the pentavalent state to provide uniform signal response. For methods 200.7 and 3120 B, both samples and standards must be diluted in the same mixed

acid matrix concentration of nitric and hydrochloric acid with the addition of 100 μL of 30% hydrogen peroxide per 100ml of solution. For direct

analysis of arsenic with method 200.8 using ultrasonic nebulization, samples and standards must contain one mg/L of sodium hypochlorite.

*******

(2) * * *

38980 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

Contaminant Preservative 1 Container 2 Time 3

*******

Arsenic ......................... Conc HNO3 to pH <2 ........................................................................... P or G ........................ 6 months.

* * * * * **

1When indicated, samples must be acidified at the time of collection to pH <2 with concentrated acid or adjusted with sodium hydroxide to pH

> 12. When chilling is indicated the sample must be shipped and stored at 4°C or less. 2P = plastic, hard or soft; G=glass, hard or soft.

3 In all cases samples should be analyzed as soon after collection as possible. Follow additional (if any) information on preservation, containers or holding times that is specified in method.

* * * * * * *

(3) * * *

(ii) * * *

Contaminant Acceptance limit

*******

Arsenic ............................................................................... ±30 at ≥0.005 mg/l

*******

* * * * *

6. Section 141.24 is amended by:

a. Adding one sentence to the end of

paragraph (f)(15)(i).

b. Removing the last sentence of

paragraph (f)(15)(ii) and adding in its

place two new sentences.

c. Adding paragraph (f)(22).

d. Adding a sentence to the end of

paragraph (h)(11)(i).

e. Removing the last sentence of

paragraph (h)(11)(ii) and adding in its

place two new sentences.

f. Adding paragraph (h)(20).

The revisions and additions read as

follows:

§ 141.24 Organic chemicals other than

total trihalomethanes, sampling and

analytical methods.

* * * * *

(f) * * *

(15) * * *

(i) * * * If a system fails to collect the

required number of samples,

compliance (average concentration) will

be based on the total number of samples

collected.

(ii) * * * If confirmation samples are

required by the State, the determination

of compliance will be based on the

annual average of the initial MCL

exceedance and any State-required

confirmation samples. If a system fails

to collect the required number of

samples, compliance (average

concentration) will be based on the total

number of samples collected.

* * * * *

(22) All new systems or systems that

use a new source of water that begin

operation after [DATE THREE YEARS

AFTER PUBLICATION DATE OF

FINAL RULE] must demonstrate

compliance with the MCL within a

period of time specified by the State.

The system must also comply with the

initial sampling frequencies specified by

the State to ensure a system can

demonstrate compliance with the MCL.

Routine and increased monitoring

frequencies shall be conducted in

accordance with the requirements in

this section.

* * * * *

(h) * * *

(11) * * *

(i) * * * If a system fails to collect the

required number of samples,

compliance (average concentration) will

be based on the total number of samples

collected.

(ii) * * * If confirmation samples are

required by the State, the determination

of compliance will be based on the

annual average of the initial MCL

exceedance and any State-required

confirmation samples. If a system fails

to collect the required number of

samples, compliance (average

concentration) will be based on the total

number of samples collected.

* * * * *

(20) All new systems or systems that

use a new source of water that begin

operation after [DATE THREE YEARS

AFTER PUBLICATION OF THE FINAL

RULE] must demonstrate compliance

with the MCL within a period of time

specified by the State. The system must

also comply with the initial sampling

frequencies specified by the State to

ensure a system can demonstrate

compliance with the MCL. Routine and

increased monitoring frequencies shall

be conducted in accordance with the

requirements in this section.

Subpart F—[Amended]

7. In § 141.51(b) , the table is amended

by adding in alphabetical order an entry

for Arsenic to read as follows:

§ 141.51 Maximum contaminant level goals

for inorganic contaminants.

* * * * *

(b) * * *

Contaminant MCLG (mg/l)

*****

Arsenic ...................... zero

*****

Subpart G—[Amended]

8. Section 141.60 is amended by

adding paragraph (b)(4) to read as

follows:

§ 141.60 Effective dates.

* * * * *

(b) * * *

(4) The compliance date for

§ 141.62(b)(16) is [DATE 5 YEARS

AFTER PUBLICATION DATE OF THE

FINAL RULE] for community water

systems serving 10,000 people or less,

and [DATE 3 YEARS AFTER

PUBLICATION DATE OF THE FINAL

RULE] for all other community water

systems.

9. Section 141.62 is amended by:

a. Revising the second sentence of

paragraph (b).

b. Adding entry ‘‘(16)’’ to the table in

paragraph (b).

c. Adding an entry and footnote for

‘‘Arsenic’’ in alphabetical order to the

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38981

table in paragraph (c) and revising the

table heading.

d. Adding paragraph (d).

The revisions and additions read as

follows:

§ 141.62 Maximum contaminant levels for

inorganic contaminants.

* * * * *

(b) * * * The maximum contaminant

level specified in paragraphs (b)(1) and

(b)(16) of this section only apply to

community water systems. * * *

Contaminant MCL (mg/l)

*****

(16) Arsenic ............... 0.005

(c) * * *

BAT FOR INORGANIC COMPOUNDS LISTED IN SECTION 141.62(B)

Chemical name BAT(s)

*******

Arsenic 4 .................................................................................................... 1, 2, 5, 6, 7, 9

* * * * * * *

4BATs for Arsenic V. Pre-oxidation may be required to convert Arsenic III to Arsenic V.

(d) The Administrator, pursuant to section 1412 of the Act, hereby identifies in the following table the affordable

technology, treatment technique, or other means available to systems serving 10,000 persons or fewer for achieving

compliance with the maximum contaminant level for arsenic:

SMALL SYSTEM COMPLIANCE TECHNOLOGIES (SSCTS) 1 FOR ARSENIC 2

Small System Compliance Technology Affordable for listed small system

categories 3

Activated Alumina (centralized) ............................................................................................................................. All size categories

Activated Alumina (Point-of-Entry) 4 ...................................................................................................................... All size categories

Activated Alumina (Point-of-Use) 4 ........................................................................................................................ All size categories

Coagulation/Filtration ............................................................................................................................................. 501–3,300, 3,301–10,000

Coagulation-assisted Microfiltration ....................................................................................................................... 501–3,300, 3,301–10,000

Ion Exchange ......................................................................................................................................................... All size categories

Lime Softening ....................................................................................................................................................... 501–3,300, 3,301–10,000

Oxidation/Filtration 5 ............................................................................................................................................... All size categories

Reverse Osmosis (centralized) ............................................................................................................................. 501–3,300, 3,301–10,000

Reverse Osmosis (Point-of-Use) 4 ......................................................................................................................... All size categories

1Section 1412(b)(4)(E)(ii) of the SDWA specifies that SSCTs must be affordable and technically feasible for small systems.

2SSCTs for Arsenic V. Pre-oxidation may be required to convert Arsenic III to Arsenic V.

3The Act (ibid.) specifies three categories of small systems: (i) those serving 25 or more, but fewer than 501, (ii) those serving more than 500,

but fewer than 3,301, and (iii) those serving more than 3,300, but fewer than 10,001. 4When POU or POE devices are used for compliance, programs to ensure proper long-term operation, maintenance, and monitoring must be

provided by the water system to ensure adequate performance. 5For use only when the removal efficiency needed to reach an MCL is less than 50%.

Subpart O—[Amended]

10. Section 141.154 is amended by

revising paragraph (b) to read as follows:

§ 141.154 Required additional health

information.

* * * * *

(b) Beginning [30 DAYS AFTER

PUBLICATION DATE OF THE FINAL

RULE], community water systems that

detect arsenic above 0.005 mg/L must

make a good faith effort, as described in

§ 141.155(b) to provide to its customers

an annual report that contains the

information specified in § 141.153 for

arsenic.

* * * * *

11. The table in Appendix A,

published at 65 FR 26024 on May 4,

2000 and effective June 5, 2000, is

amended by revising the entry for

arsenic to read as follows:

Appendix A to Subpart O.—Regulated

Contaminants

* * * * *

38982 Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules

Contaminant (units)

Traditional

MCL

in mg/L

To convert

for CCR,

multiply by

MCL in

CCR units MCLG Major sources in drinkingwater Health effects language

*******

Inorganic contaminants:

*******

Arsenic (ppb) .......... 0.005 1000 5 0 Erosion of natural deposits;

Runoff from orchards; Runoff from glass and electronics production wastes.

Some people who drink water

containing arsenic in excess

of the MCL over many

years could experience skin

damage or problems with

their circulatory system, and

may have an increased risk

of getting cancer.

*******

Key:

*******

ppb = parts per billion, or micrograms per liter (μg/l) *******

Subpart Q—[Amended]

12. Section 141.203(a), published at

65 FR 26036 on May 4, 2000, and

effective June 5, 2000, is amended by

adding entry (4) in numerical order to

Table 1 to read as follows:

§ 141.203 Tier 2 Public Notice—Form,

manner, and frequency of notice.

(a) * * *

TABLE 1 TO § 141.203.—VIOLATION CATEGORIES AND OTHER SITUATIONS REQUIRING A TIER 2 PUBLIC NOTICE

*******

(4) Non-transient non-community water systems exceeding the arsenic MCL.

* * * * *

13. Appendix A to Subpart Q,

published at 65 FR 26040 on May 4,

2000, effective June 5, 2000, is amended

in the table by revising the entry for ‘‘2.

Arsenic’’ under B. Inorganic Chemicals

(IOCs), revising endnote 1 and adding

endnotes 18 and 19 to read as follows:

Appendix A to Subpart Q of Part 141.—

NPDWR Violations and Other

Situations Requiring Public Notice1

Contaminant

MCL/MRDL/TT violations 2 Monitoring & testing procedure violations

Tier of public notice required

Citation Tier of public notice required

Citation

*******

B. Inorganic Chemicals (IOCs)

*******

2. Arsenic ..................................................................................................... 2 18 141.62(b) 3 19 141.23(a), (c)

*******

Appendix A—Endnotes

1. Violations and other situations not listed

in this table (e.g., reporting violations and

failure to prepare Consumer Confidence

Reports), do not require notice, unless

otherwise determined by the primacy agency.

Primacy agencies may, at their option, also

require a more stringent public notice tier

(e.g., Tier 1 instead of Tier 2 or Tier 2 instead

of Tier 3) for specific violations and

situations listed in this Appendix, as

authorized under § 141.202(a) and

§ 141.203(a).

2. MCL—Maximum contaminant level,

MRDL—Maximum residual disinfectant

level, TT—Treatment technique.

* * * * *

18. The arsenic MCL citations apply [DATE

5 YEARS AFTER PUBLICATION DATE OF

THE FINAL RULE] for community water

systems serving 10,000 people or less and

[DATE 3 YEARS AFTER PUBLICATION

DATE OF THE FINAL RULE] for all other

community water systems and non-transient

non-community water systems. Until then,

the citations are § 141.11(b) and § 141.23(n).

19. The arsenic Tier 3 violation MCL

citations apply [DATE 5 YEARS AFTER

PUBLICATION DATE OF THE FINAL RULE]

for community water systems serving 10,000

people or less and [DATE 3 YEARS AFTER

PUBLICATION DATE OF THE FINAL RULE]

for all other community water systems. Until

then, the citations are § 141.23(a,l).

14. Appendix B to Subpart Q

published at 65 FR 26043 on May 4,

2000, effective June 5, 2000, is amended

in the table by revising entry ‘‘9.

Arsenic’’ and adding footnote 23 to read

as follows:

Appendix B to Subpart Q of Part 141.—

Standard Health Effects Language for Public

Notification

Federal Register / Vol. 65, No. 121 / Thursday, June 22, 2000 / Proposed Rules 38983

Contaminant MCLG1

mg/L MCL2 mg/L Standard health effects language for public notification

*******

9. Arsenic 23 ........................................ 0 0.005 Some people who drink water containing arsenic in excess of the MCL

over many years could experience skin damage or problems with thier

circulatory system, and may have an increased risk of getting cancer.

*******

Appendix B—Endnotes

1. MCLG—Maximum contaminant level

goal.

2. MCL—Maximum contaminant level.

* * * * *

23. These arsenic values apply [DATE 5

YEARS AFTER PUBLICATION DATE OF

THE FINAL RULE] for community water

systems serving 10,000 people or less and

[DATE 3 YEARS AFTER PUBLICATION

DATE OF THE FINAL RULE] for all other

community water systems and non-transient

non-community water systems. Until then,

the MCL is 0.050 mg/L and there is no

MCLG.

PART 142—NATIONAL PRIMARY

DRINKING WATER REGULATIONS

IMPLEMENTATION

1. The authority citation for part 142

continues to read as follows:

Authority: 42 U.S.C. 300f, 300g–1, 300g–2,

300g–3, 300g–4, 300g–5, 300g–6, 300j–4,

300j–9, and 300j–11.

Subpart B—Primary Enforcement

Responsibility

2. In § 142.16, revise paragraph (e)

introductory text and add paragraphs (j)

and (k) to read as follows:

§ 142.16 Special primacy requirements.

* * * * *

(e) An application for approval of a

State program revision which adopts the

requirements specified in §§ 141.11,

141.23, 141.24, 141.40, 141.61 and

141.62 for a newly regulated

contaminant must contain the following

(in addition to the general primacy

requirements enumerated elsewhere in

this part, including the requirement that

State regulations be at least as stringent

as the federal requirements):

* * * * *

(j) An application for approval of a

State program revision which adopts the

requirements specified in §§ 141.11,

141.23, 141.24, 141.32, 141.40, 141.61

and 141.62 for an existing regulated

contaminant must contain the following

(in addition to the general primacy

requirements enumerated elsewhere in

this part, including the requirement that

State regulations be at least as stringent

as the federal requirements):

(1) If a State chooses to issue waivers

from the monitoring requirements in

§§ 141.23, 141.24, and 141.40, the State

shall describe the procedures and

criteria which it will use to review

waiver applications and issue wavier

determinations. The State shall provide

the same information required in

paragraphs (e)(1)(i) and (ii) of this

section. States may update their existing

waiver criteria or use the requirements

submitted under the National Primary

Drinking Water Regulations for the

inorganic and organic contaminants

(i.e., Phase II/V rule) in paragraph (e) of

this section. States may simply note in

their application any revisions to

existing waiver criteria or note that the

same procedures to issue waivers will

be used.

(2) A monitoring plan by which the

State will assure all systems complete

the required monitoring with the

regulatory deadlines. States may update

their existing monitoring plan or use the

same monitoring plan submitted under

the National Primary Drinking Water

Regulations for the inorganic and

organic contaminants (i.e. Phase II/V

rule) in paragraph (e) of this section.

States may simply note in their

application any revisions to an existing

monitoring plan or note that the same

monitoring plan will be used. The State

must demonstrate that the monitoring

plan is enforceable under State law.

(k) States establish the initial

monitoring requirements for new

systems and new sources. States must

explain their initial monitoring

schedules and how these monitoring

schedules ensure that public water

systems and sources that begin

operation after [DATE THIRTY DAYS

AFTER PUBLICATION OF THE FINAL

RULE] comply with MCL’s and

monitoring requirements. States must

also specify the time frame in which

new systems will demonstrate

compliance with the MCLs.

4. In § 142.62(b), the table is amended

by revising the table heading and adding

arsenic in alphabetical order to the list

of contaminants to read as follows:

§ 142.62 Variances and exemptions from

the maximum contaminant levels for

organic and inorganic chemicals

* * * * *

(b) * * *

BAT FOR INORGANIC COMPOUNDS LISTED IN § 141.62(B) 1

Chemical name BAT(s)

*******

Arsenic ...................................................................................................... 1, 2, 5, 6, 7, 9

*******

* * * * *

Key to BATs in Table

1 = Activated Alumina

2 = Coagulation/Filtration (not BAT for

systems < 500 service connections)

* * * * *

5 = Ion Exchange

6 = Lime Softening (not BAT for systems <

500 service connections)

7 = Reverse Osmosis

* * * * *

9 = Electrodialysis

* * * * *

[FR Doc. 00–13546 Filed 6–21–00; 8:45 am]

BILLING CODE 6560–50–P