Monday,

January 22, 2001

Part VIII

Environmental

Protection Agency

40 CFR Parts 9, 141, and 142

National Primary Drinking Water

Regulations; Arsenic and Clarifications to

Compliance and New Source

Contaminants Monitoring; Final Rule

6976 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Parts 9, 141 and 142

[WH–FRL–6934–9]

RIN 2040–AB75

National Primary Drinking Water

Regulations; Arsenic and Clarifications

to Compliance and New Source

Contaminants Monitoring

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Final rule.

SUMMARY: Today EPA is establishing a

health-based, non-enforceable

Maximum Contaminant Level Goal

(MCLG) for arsenic of zero and an

enforceable Maximum Contaminant

Level (MCL) for arsenic of 0.01 mg/L (10

μg/L). This regulation will apply to nontransient non-community water

systems, which are not presently subject

to standards on arsenic in drinking

water, and to community water systems.

In addition, EPA is publishing

clarifications for monitoring and

demonstration of compliance for new

systems or sources of drinking water.

The Agency is also clarifying

compliance for State-determined

monitoring after exceedances for

inorganic, volatile organic, and

synthetic organic contaminants. Finally,

EPA is recognizing the State-specified

time period and sampling frequency for

new public water systems and systems

using a new source of water to

demonstrate compliance with drinking

water regulations. The requirement for

new systems and new source

monitoring will be effective for

inorganic, volatile organic, and

synthetic organic contaminants.

DATES: This rule is effective March 23,

2001, except for the amendments to

§§ 141.23(i)(1), 141.23(i)(2),

141.24(f)(15), 141.24(h)(11),

141.24(h)(20), 142.16(e), 142.16(j), and

142.16(k) which are effective January

22, 2004.

The compliance date for requirements

related to the clarification for

monitoring and compliance under

§§ 141.23(i)(1), 141.23(i)(2),

141.24(f)(15), 141.24(f)(22),

141.24(h)(11), 141.24(h)(20), 142.16(e),

142.16(j), and 142.16(k) is January 22,

2004. The compliance date for

requirements related to the revised

arsenic standard under §§ 141.23(i)(4),

141.23(k)(3), 141.23(k)(3)(ii), 141.51(b),

141.62(b), 141.62(b)(16), 141.62(c),

141.62(d), and 142.62(b) is January 23,

2006. For purposes of judicial review,

this rule is promulgated as of January

22, 2001.

ADDRESSES: Copies of the public

comments received, EPA responses, and

all other supporting documents are

available for review at the U.S. EPA

Water Docket (4101), East Tower B–57,

401 M Street, SW, Washington DC

20460. For an appointment to review

the docket, call 202–260–3027 between

9 a.m. and 3:30 p.m. and refer to Docket

W–99–16.

FOR FURTHER INFORMATION CONTACT: The

Safe Drinking Water Hotline, phone:

(800) 426–4791, or (703) 285–1093, email: hotline.sdwa@epa.gov for general

information about, and copies of, this

document and the proposed rule. For

technical inquiries, contact: Jeff Kempic,

(202) 260–9567, e-mail:

kempic.jeffrey@epa.gov for treatment

and costs, and Dr. John B. Bennett, (202)

260–0446, e-mail:

bennett.johnb@epa.gov for benefits.

SUPPLEMENTARY INFORMATION:

Regulated Entities

A public water system (PWS), 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 regulated entities

Industry ........................................... Privately owned/operated community water supply systems using ground water, surface 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, surface

water, or mixed ground and surface water.

Federal Government ....................... Federally owned/operated community water supply systems using ground water, surface 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

the general information contact listed in

the section listing contacts for further

information.

Abbreviations used in this rule

<—less than

≤—less than or equal to

>—greater than

≥—greater than or equal to

±—plus or minus

§ —section

σ—σ, Greek letter, in statistics

represents standard deviation

μg—Microgram, one-millionth of a gram

(3.5 × 10¥8 of an ounce)

μg/L—micrograms per liter

AA—Activated alumina

AIC—Akaike Information Criterion

ACWA—Association of California Water

Agencies

AMWA—Association of Metropolitan

Water Agencies

APHA—American Public Health

Association

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 6977

ARARs—Applicable or relevant and

appropriate requirements

As (III)—Trivalent arsenic. Common

inorganic form in water is arsenite

As (V)—Pentavalent arsenic. Common

inorganic form in water is arsenate

ASDWA— Association of State Drinking

Water Administrators

AsH3—Arsine

ASTM—American Society for Testing

and Materials

ATSDR—Agency for Toxic Substances

and Disease Registry, U.S. Department

of Health & Human Services

AWWA—American Water Works

Association

AWWARF—American Water Works

Association Research Foundation

BAT—Best available technology

BV—Bed volume

CCR—Consumer Confidence Report

CERCLA—Comprehensive

Environmental Response,

Compensation, and Liability Act

administered by EPA for hazardous

substances

C/F—Modified coagulation/filtration

CFR—Code of Federal Regulations

CSFII—Continuing Survey of Food

Intakes by Individuals

CWA—Clean Water Act administered by

EPA for surface waters of the U.S.

CWS—Community water system

CWSS—Community Water System

Survey

DMA—Dimethyl arsinic acid, cacodylic

acid, (CH3)2HAsO2

DNA—Deoxyribonucleic acid

DWSRF—Drinking Water State

Revolving Fund

EA—Economic analysis

EDR—Electrodialysis reversal

EEAC—Environmental Economics

Advisory Committee

e.g.—exempli gratia, Latin for ‘‘for

example’’

EPA—U.S. Environmental Protection

Agency

et al.—et alia, Latin for ‘‘and others’’

FACA—Federal Advisory Committee

Act

FR—Federal Register

FRFA—Final Regulatory Flexibility

Analysis

FSIS—Federalism Summary Impact

Statement

GDP—Gross Domestic Product

GFAA—Graphite furnace atomic

absorption

GHAA—Gaseous hydride atomic

absorption

GI—Gastrointestinal

GW—Ground water

GWR—Ground Water Rule

HRRCA—Health Risk Reduction and

Cost Analysis

ICP–AES—Inductively coupled plasmaatomic emission spectroscopy

ICP–MS—Inductively coupled plasma

mass spectroscopy

ICR—Information collection request

i.e.—id est, Latin for ‘‘that is’’

IOCs—Inorganic contaminants

ISCV—Intra-system coefficient of

variation

IX—Ion exchange

L—Liter, also referred to as lower case

‘‘l’’ in older citations

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

LS—Modified lime softening

LT1/FBR—Long Term 1 Enhanced

Surface Water Treatment and Filter

Backwash Recycling Rule

MCL—Maximum contaminant level

MCLG—Maximum contaminant level

goal

MDL—Method detection limit

mg—Milligrams, one-thousandth of a

gram, 1 milligram=1,000 micrograms

mg/kg—Milligrams arsenic per kilogram

body weight or soil weight

mg/L—Milligrams per liter

MHI—Mean household income

MMA—Monomethyl arsenic, arsonic

acid, CH3H2ASO3

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 for EPA

NIRS—National Inorganic and

Radionuclide Survey done by EPA

NODA—Notice of Data Availability

NOMS—National Organic Monitoring

Survey done by EPA

NPDES—National Pollutant Discharge

Elimination System for CWA

NPDWR—National primary drinking

water regulation

NR—Not reported

NRC—National Research Council, the

operating arm of NAS

NTNCWS—Non-transient noncommunity water system

NTTAA—National Technology Transfer

and Advancement Act

NWIS—National Water Information

System of USGS

OGWDW—Office of Ground Water and

Drinking Water in EPA

OMB—Office of Management and

Budget

PE—Performance evaluation, studies to

certify laboratories for EPA drinking

water testing

pH—Negative log of hydrogen ion

concentration

PNR—Public Notification Rule

POE—Point-of-entry treatment devices

POTWs—Publicly owned treatment

works, treat wastewater

POU—Point-of-use treatment devices

ppb—Parts per billion

ppm—Parts per million

PQL—Practical quantitation level

PRA—Paperwork Reduction Act

psi—Pounds per square inch

PT—Performance testing

PUC—Public utilities commission

PWS—Public water systems

QALYs—Quality adjusted life years

RCRA—Resource Conservation and

Recovery Act

REF—Relative exposure factors

RFA—Regulatory Flexibility Act

RIA—Regulatory Impact Analysis

RO—Reverse osmosis

RUS—Rural Utilities Service

RWS—Rural Water Survey

SAB—Science Advisory Board

SBAR—Small Business Advocacy

Review

SBREFA—Small Business Regulatory

Enforcement Fairness Act

SD—Standard deviation

SDWA—Safe Drinking Water Act

SDWIS—Safe Drinking Water

Information System

SEER—Surveillance, Epidemiology, and

End Results

SM—Standard Method for Examination

of Water and Wastewater

SMF—Standardized monitoring

framework

SMRs—Standardized mortality ratios

SO4—Sulfate

SOCs—Synthetic organic contaminants

STP–GFAA—Stabilized temperature

platform graphite furnace atomic

absorption

SW—Surface water

TBLLs—Technically based local limits

TC—Toxicity Characteristic, RCRA

hazardous waste

TCLP—Toxicity Characteristic Leaching

Procedure, tests for hazardous waste

TDS—Total dissolved solids

TMF—Technical, managerial, financial

capacity

TOC—Total organic carbon

UMRA—Unfunded Mandates Reform

Act

URTH—Unreasonable risk to health

U.S.—United States

USDA—US Department of Agriculture

USGS—US Geological Survey

UV—Ultraviolet

VOCs—Volatile organic contaminants

VSL—Value of statistical life

VSLY—Value of statistical life year

WHO—World Health Organization

WS—Water supply

WTP—Willingness-to-pay

Table of Contents

I. Background and Summary of the Final

Rule

A. What Did EPA Propose?

B. Overview of the Notice of Data

Availability (NODA)

C. Does This Regulation Apply to My Water

System?

6978 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

D. What are the Final Drinking Water

Regulatory Standards for Arsenic

(Maximum Contaminant Level Goals and

Maximum Contaminant Levels)?

E. Will There be a Health Advisory?

F. What are the Best Available Technologies

For Removing Arsenic From Drinking

Water?

1. BAT technologies

2. Preoxidation

3. Factors affecting listing technologies

4. Other technologies evaluated, but not

designated as BAT

5. Waste disposal

G. Treatment Trains Considered For Small

Systems

1. Can my water system use point-of-use

(POU), point-of-entry (POE), or bottled

water to comply with this regulation?

2. What are the affordable treatment

technologies for small systems?

3. Can my water system get a small system

variance from an MCL under today’s

rule?

H. Can My System Get a General Variance or

Exemption from the MCL Under Today’s

Rule?

I. What Analytical Methods are Approved for

Compliance Monitoring of Arsenic and

What are the Performance Testing

Criteria for Laboratory Certification?

1. Approved analytical methods

2. Performance testing criteria for

laboratory certification

J. How Will I Know if My System Meets the

Arsenic Standard?

1. Sampling points and grandfathering of

monitoring data

2. Compositing of samples

3. Calculation of violations

4. Monitoring and compliance schedule

K. What do I Need To Tell My Customers?

1. Consumer Confidence Reports

a. General requirements

b. Special informational statement

2. Public Notification

L. What Financial Assistance Is Available for

Complying With This Rule?

M. What is the Effective Date and

Compliance Date for the Rule?

N. How Were Stakeholders Involved in the

Development of This Rule?

II. Statutory Authority

III. Rationales for Regulatory Decisions

A. What is the MCLG?

B. What is the Feasible Level?

1. Analytical measurement feasibility

2. Treatment

C. How Did EPA Revise Its National

Occurrence Estimates?

1. Summary of occurrence data and

methodology

2. Corrections and additions to the data

3. Changes to the methodology

4. Revised occurrence results

D. How Did EPA Revise Its Risk Analysis?

1. Health risk analysis

a. Toxic forms of arsenic

b. Effects of acute toxicity

c. Non-cancer effects associated with

arsenic.

d. Cancers associated with arsenic

e. How does arsenic cause cancer?

f. What is the quantitative relationship

between exposure and cancer effects that

may be projected for exposures in the

U.S.?

g. Is it appropriate to assume linearity for

the dose-response assessment for arsenic

at low doses given that arsenic is not

directly reactive with DNA?

2. Risk factors/bases for upper- and lowerbound analyses

a. Water consumption

b. Relative Exposure Factors

c. Arsenic occurrence

d. Risk distributions

e. Estimated risk reductions

f. Lower-bound analyses

g. Cases avoided

3. Sensitive subpopulations

4. Risk window

E. What are the Costs and Benefits at 3, 5, 10,

and 20 μg/L?

1. Summary of cost analysis

a. Total national costs

b. Household costs

2. Summary of benefits analysis

a. Primary analysis

b. Sensitivity analysis on benefits valuation

c. SAB recommendations

d. Analytical approach

e. Results

3. Comparison of costs and benefits

a. Total national costs and benefits

b. National net benefits and benefit-cost

ratios

c. Incremental costs and benefits

d. Cost-per-case avoided

4. Affordability

F. What MCL Is EPA Promulgating and What

Is the Rationale for This Level?

1. Final MCL and overview of principal

considerations

2. Consideration of health risks

3. Comparison of benefits and costs

4. Rationale for the final MCL

a. General considerations

b. Relationship of MCL to the feasible level

(3 μg/L)

c. Reanalysis of proposed MCL and

comparison to final MCL

d. Consideration of higher MCL options

e. Conclusion

IV. Rule Implementation

A. What are the Requirements for Primacy?

B. What are the Special Primacy

Requirements?

C. What are the State Recordkeeping

Requirements?

D. What are the State Reporting

Requirements?

E. When does a State Have to Apply for

Primacy?

F. What are Tribes Required To Do Under

This Regulation?

V. Responses to Major Comments Received

A. General Comments

1. Sufficiency of information and adequacy

of procedural requirements to support a

final rule

2. Suggestions for development of an

interim standard

3. Public involvement and opportunity for

comment

4. Relation of MCL to the feasible level

5. Relationship of MCL to other regulatory

programs

6. Relation of MCL to WHO standard

7. Regulation of non-transient noncommunity water systems (NTNCWSs)

8. Extension of effective date for large

systems

B. Health Effects of Arsenic

1. Epidemiology data

2. Dose-response relationship

3. Suggestions that EPA await further

health effects research

4. Sensitive subpopulations

5. EPA’s risk analysis

6. Setting the MCLG and the MCL

C. Occurrence

1. Occurrence data

2. Occurrence methodology

3. Co-occurrence

D. Analytical Methods

1. Analytical interferences

2. Demonstration of PQL (includes

acceptance limits)

3. Acidification of samples

E. Monitoring and Reporting Requirements

1. Compliance determinations

2. Monitoring of POU devices

3. Monitoring and reporting for NTNCWSs

4. CCR health language and reporting date

5. Implementation guidance

6. Rounding analytical results

F. Treatment Technologies

1. Demonstration of technology

performance

2. Barriers to technology application

3. Small system technology application

4. Waste generation and disposal

a. Anion exchange

b. Activated alumina

c. Reverse osmosis

5. Emerging technologies

G. Costs

1. Disparity of costs

a. What is EPA’s response to major

comments on the decision tree for the

proposed rule?

b. What is EPA’s response to comments on

system level costs?

c. What is EPA’s response to comments

that state the report ‘‘Cost Implications of

a Lower Arsenic MCL’’ (Frey et al.,

2000), be used as a basis for reflecting

more realistic national costs than EPA’s

estimates?

2. Affordability

3. Combined cost of new regulations

4. Projected effects of the new standard on

other regulatory programs.

H. Benefits of Arsenic Reduction

1. Timing of benefits accrual (latency)

2. Use of the Value of Statistical Life (VSL)

3. Use of alternative methodologies for

benefits estimation

4. Comments on EPA’s consideration of

nonquantifiable benefits

5. Comments on EPA’s assumption of

benefits accrual prior to rule

implementation

I. Risk Management Decision

1. Role of uncertainty in decision making

2. Agency’s interpretation of benefits

justify costs provision

3. Alternative regulatory approaches

4. Standard for total arsenic vs. speciesspecific standards

J. Health Risk Reduction and Cost Analysis

(HRRCA)

1. Notice and comment requirement

2. Conformance with SDWA requirements

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 6979

VI. Administrative and Other 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.

C. Unfunded Mandates Reform Act (UMRA)

of 1995

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, Tribal, and local

governments

g. Nature of State, Tribal, and local

government concerns and how EPA

addressed these concerns

h. Regulatory alternatives considered

i. Selection of the regulatory

alternative

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 Orders 13084 and 13175:

Consultation and Coordination with

Indian Tribal Governments

J. Plain Language

K. Congressional Review Act

L. Consultations with the Science

Advisory Board, National Drinking

Water Advisory Council, and the

Secretary of Health and Human

Services

M. Likely Effect of Compliance With the

Arsenic Rule on the Technical,

Financial, and Managerial Capacity

of Public Water Systems

VI. References

List of Tables

Table I.F–1.—Best Available Technologies

and Removal Rates

Table I.G–1.—Treatment Technology Trains

Table I.G–2.—Baseline Values for Small

Systems Categories

Table I.G–3.—Available Expenditure Margin

for Affordable Technology

Determinations

Table I.G–4.—Design and Average Daily

Flows Used for Affordable Technology

Determinations

Table I.G–5.—Affordable Compliance

Technology Trains for Small Systems

with population 25–500

Table I.G–6.—Affordable Compliance

Technology Trains for Small Systems

with populations 501–3,300 and 3,301 to

10,000

Table I.I–1.—Approved Analytical Methods

(40 CFR 141.23) for Arsenic at the MCL

of 0.01 mg/L

Table III.C–1.—Summary of Occurrence

Databases for the Proposed and Final

Rules

Table III.C–2.—Alaska PWS Inventories:

Baseline Handbook and Corrected

Table III.C–3.—National Occurrence

Exceedance Probability Estimates

Table III.C–4.—Parameters of Lognormal

Distributions Fitted to National

Occurrence Distributions

Table III.C–5.—Regional Occurrence

Exceedance Probability Estimates

Table III.C–6.—Statistical Estimates of

Numbers of Systems with Average

Finished Arsenic Concentrations in

Various Ranges

Table III.C–7.—Estimated Intra-System

Coefficients of Variation

Table III.C–8.—Comparison of National

Arsenic Occurrence Estimates

Table III.D–1.—Life-Long Relative Exposure

Factors

Table III.D–2(a).—Cancer Risks for U.S.

Populations Exposed At or Above MCL

Options, after Treatment1,2 (Without

Adjustment for Arsenic in Food and

Cooking Water)

Table III.D–2(b).—Cancer Risks for U.S.

Populations Exposed At or Above MCL

Options, after Treatment1,2 (With

Adjustment for Arsenic Exposure in

Food and Cooking Water)

Table III.D–2(c).—Cancer Risks for U.S.

Populations Exposed At or Above MCL

Options, after Treatment1 (Lower Bound

With Food and Cooking Water

Adjustment, Upper Bound Without Food

and Cooking Water Adjustment)

Table III.D–3.—Annual Total (Bladder and

Lung) Cancer Cases Avoided from

Reducing Arsenic in CWSs and

NTNCWS

Table III.E–1.—Total Annual National

System and State Compliance Costs

Table III.E–2.—Mean Annual Costs per

Household

Table III.E–3.—Estimated Benefits from

Reducing Arsenic in Drinking Water

Table III.E–4.—Sensitivity of the Primary

VSL Estimate to Changes in Latency

Period Assumptions, Income Growth,

and Other Adjustments

Table III.E–5.—Sensitivity of Combined

Annual Bladder and Lung Cancer

Mortality Benefits Estimates to Changes

in VSL Adjustment Factor Assumptions

Table III.E–6.—Sensitivity of Combined

Annual Bladder and Lung Cancer

Mortality Benefits Estimates to Changes

in VSL Adjustment Factor Assumptions

Table III.E–7.—Estimated Annual Costs and

Benefits from Reducing Arsenic in

Drinking Water

Table III.E–8 Summary of National Annual

Net Benefits and Benefit-Cost Ratios,

Combined Bladder and Lung Cancer

Cases

Table III.E–9 Estimates of the Annual

Incremental Risk Reduction, Costs, and

Benefits of Reducing Arsenic in Drinking

Water

Table III.E–10. Annual Cost Per Cancer Case

Avoided for the Final Arsenic Rule—

Combined Bladder and Lung Cancer

Cases

TABLE V.F–4.1 Treatment Trains in Final

Versus Proposed Arsenic Rule Decision

Tree

Table V.F–4.2 New or Revised Treatment

Trains

Table VI.B–1. Profile of the Universe of Small

Water Systems Regulated Under the

Arsenic Rule

I. Background and Summary of the

Final Rule

A. What Did EPA Propose?

On June 22, 2000, the Federal

Register published EPA’s proposed

arsenic regulation for community water

systems and non-transient noncommunity water systems (65 FR 38888;

EPA, 2000i). EPA proposed a healthbased, non-enforceable goal, or

Maximum Contaminant Level Goal

(MCLG), of zero micrograms per liter

(μg/L) and a Maximum Contaminant

Level (MCL) of 5 μg/L. The Agency also

requested comment on alternate MCL

levels of 3 μg/L, 10 μg/L, and 20 μg/L.

(In the proposed rule EPA expressed

arsenic concentration in milligrams per

liter (mg/L) or parts per million, which

matches the units of the former and

current standard for arsenic. Except as

noted, the Agency will refer to arsenic

concentration in micrograms per liter

(μg/L) in this preamble.)

EPA based the June 2000 proposal on

extensive analysis including a careful

consideration of the following issues: a

nonzero MCLG; occurrence of arsenic in

public water systems; our approach for

estimating national occurrence and cooccurrence; acceptance limits used to

establish the practical quantitation level

(PQL); rounding of measured values for

compliance purposes; extending

compliance by two years for systems

serving under 10,000 people in order to

add capital improvements; dates for

reporting changes in the consumer

confidence reports and public

notification; appropriateness of the

national affordability criteria; affordable

technologies for small systems;

implementation issues for point-of-use

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

treatments; appropriateness of nonhazardous residual costing; our overall

analysis of costs; adjusting benefits

estimates (e.g., for factors such as

latency); our approach for considering

uncertainties that affected risk; use of

the authority to set an MCL at a level

other than the feasible MCL; expression

of the MCL as total arsenic; approaches

to regulation of NTNCWSs; State

program revisions; selenium levels as an

attenuation factor in arsenic toxicity;

impacts on small entities; use of

consensus analytical methods; methods

to address environmental justice

concerns; and comments on use of plain

6980 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

language. We asked commenters to

submit data and comments on these

issues, as well as any other issues raised

in the proposal.

The proposal reflected several types

of technical evaluations, including

analytical methods performance and

laboratory capacity; the likelihood of

different size water systems choosing

treatment technologies based on source

water characteristics; and the national

occurrence of arsenic in drinking water

supplies. Furthermore, the Agency

assessed the quantifiable and

nonquantifiable costs and health risk

reduction benefits likely to occur at the

treatment levels considered, and the

effects of arsenic on sensitive

subpopulations.

The proposed MCL was consistent

with the Agency’s use of the new

benefit/cost provisions of the Safe

Drinking Water Act (SDWA), as

amended in 1996 (see section II. of this

preamble for additional information

about this provision). EPA proposed 3

μg/L as the feasible MCL, after

considering treatment costs and

efficiency under field conditions as well

as considering the appropriate

analytical methods. Because EPA

determined that the benefits of

regulating arsenic at the feasible level

would not justify the costs, the Agency

proposed an MCL of 5 μg/L, while

requesting comment on MCL options of

3 μg/L (the feasible level), 10 μg/L, and

20 μg/L.

We based our estimates of large

system compliance costs primarily on

costs for coagulation/filtration and lime

softening, although we consider several

other technologies to be appropriate as

best available technology (BAT)

technologies. (See Table I.F–1.) For

small-system (systems serving 10,000

people and less) compliance costs, we

considered the costs for ion exchange,

activated alumina, reverse osmosis, and

nanofiltration. EPA proposed extending

the effective date to five years after the

final rule issuance for small community

water systems and maintaining the

effective date at three years after

promulgation for all other community

water systems. EPA proposed 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. EPA proposed

that NTNCWSs monitor for arsenic and

report exceedances of the MCL.

The Agency also clarified the

procedure used for determining

compliance after exceedances for

inorganic, volatile organic, and

synthetic organic contaminants in

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

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

EPA proposed that new systems and

systems using a new source of water be

required to demonstrate compliance

with the MCLs using State-specified

time frames. The clarified new source

and new system compliance regulations

require that States establish initial

sampling frequencies and compliance

periods for inorganic, volatile organic,

and synthetic organic contaminants in

§§ 141.23(c)(9), 141.24(f)(22), and

141.24(h)(20), respectively.

B. Overview of the Notice of Data

Availability (NODA)

In the proposed rule, EPA quantified

the risk reduction and benefits of

avoiding bladder cancer and noted that

a peer-reviewed quantification of lung

cancer risk from arsenic exposure would

probably be available in time to

consider for the final rule (65 FR 38888

at 38899; EPA, 2000i). Relying upon a

discussion in the National Research

Council (NRC) report (NRC, 1999, pg. 8)

about the qualitative risks of lung cancer

(65 FR 38888 at 38944; 2000i), EPA

provided a ‘‘What-If’’ estimate of lung

cancer benefits (65 FR 38888 at 38946,

2000i) in the proposed rule. On October

20, 2000, the Federal Register published

EPA’s Notice of Data Availability

(NODA) containing a revised risk

analysis for bladder cancer and new risk

information concerning lung cancer (65

FR 63027; EPA, 2000m), and identified

a correction to Table 4 on October 27,

2000 (65 FR 64479; EPA, 2000n). The

NODA also provided information

concerning the availability of cost

curves used to develop the costs

published in the proposal.

EPA used new risk information for

lung and bladder cancer from a peerreviewed article written by Morales et

al. (2000). In the NODA, EPA explained

that the authors used several alternative

statistical models to estimate cancer

risk. EPA explained its reasons for

selecting ‘‘Model 1’’ with no

comparison population for further

analysis. We used daily water

consumption (EPA, 2000c) reported by

gender, region, age, economic status,

race, and separately for pregnant

women, lactating women, and women

in childbearing years combined with

weight data to derive exposure factors

for the U.S. We used these exposure

factors, our occurrence estimate (EPA

2000g) of populations exposed to

arsenic at different concentrations, and

the risk distributions from the Morales

et al. (2000) paper in Monte Carlo

simulations to estimate the upper bound

of risks faced by the U.S. population.

The NODA compared the bladder

cancer risks derived for the proposal

against the bladder cancer risks derived

from the Morales et al. (2000) study.

EPA also derived lung cancer risks

using the same approach and the risk

model contained in the Morales et al.

(2000) study.

EPA also used the newly calculated

risks to estimate a lower bound risk in

the U.S. This calculation took into

account the amount of additional

arsenic people in Taiwan were likely to

have ingested from water used in food

preparation. EPA showed the effects on

risks for the U.S. population at both the

mean and 90th percentile levels for

various arsenic levels in drinking water.

Based on the revised risk assessment,

we updated our assessment of the

relative risk of lung cancer as compared

to bladder cancer. The NODA indicated

that instead of being 2 to 5 times as

many fatal lung cancer cases as bladder

cancer cases (as was cited in NRC’s

Executive Summary, NRC, 1999, pg. 8 as

a qualitative estimate), the combined

risk of excess lung and bladder cancer

were thought to be only about twice that

of bladder cancer risk. EPA noted that,

while the new risks were higher than

the bladder cancer risk in the proposal,

the monetized benefits of lung cancer

would fall within the lung cancer

benefits range estimated using the

‘‘What-If’’ analysis (e.g., $19.6 million—

$224 million yearly for an MCL of 10

μg/L) in the proposal (65 FR 38888 at

38959; EPA, 2000m).

In the NODA, EPA also explained that

the docket for the proposed rule had the

November 1999 version (EPA, 1999o) of

‘‘Technologies and Costs for the

Removal of Arsenic from Drinking

Water’’ rather than the April 1999

version of the document that was the

primary source for the treatment

technology cost equations used to

generate the national cost estimate. The

national cost estimate was presented in

the ‘‘Proposed Arsenic in Drinking

Water Rule Regulatory Impact Analysis’’

(EPA, 2000h). The NODA therefore

announced the availability of the

‘‘Technologies and Costs for the

Removal of Arsenic from Drinking

Water,’’ dated April 1999 (EPA,1999b).

The NODA also noted that commenters

interested in reproducing the waste

disposal curves should consult the

‘‘Small Water System Byproducts

Treatment and Disposal Cost

Document’’ (EPA, 1993a) and ‘‘Water

System Byproducts Treatment and

Disposal Document (EPA, 1993b).’’ In

addition to placing these documents in

the docket, the NODA also specified

that an electronic copy of the treatment

technology and waste disposal

equations used in the development of

the RIA could be found in the docket.

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 6981

EPA made the April 1999 version of the

document, ‘‘Technologies and Costs for

the Removal of Arsenic from Drinking

Water’’ (EPA,1999b) available on its

arsenic webpage.

The cost methodology and cost

estimates were clearly stated and

explained in the proposal for public

review and consideration. Through a

technical oversight, we incorrectly

attributed the source for the cost curves

to the November version of the

document placed in the docket (EPA,

1999o). As a result, people could not

replicate the precise analysis we did,

should a commenter desire to do so.

More specifically, although the inputs,

assumptions, and model methodology

were clearly explained, we incorrectly

cited the sources of an intermediate step

of deriving specific cost curves from

those assumptions. Based upon the

proposal’s detailed discussion of inputs,

assumptions and associated

methodology, EPA believes the public

was fully able to review, understand,

and comment on the Agency’s estimate

of potential impacts. EPA discusses the

cost curves further in section III.E.1 of

this preamble.

C. Does This Regulation Apply to My

Water System?

The final regulation on arsenic in

drinking water promulgated today

applies to all CWSs and NTNCWSs. The

regulation not only establishes an MCLG

and MCL for arsenic, but also lists

feasible technologies and affordable

technologies for small systems that can

be used to comply with the MCL.

However, systems are not required to

use the listed technologies in order to

meet the MCL.

D. What are the Final Drinking Water

Regulatory Standards for Arsenic

(Maximum Contaminant Level Goals

and Maximum Contaminant Levels)?

In today’s rule, the MCLG is 0 μg/L,

and the enforceable MCL is 0.01 mg/L,

which is the same as 10 micrograms per

liter (μg/L) or 10 parts per billion (ppb).

EPA based the MCL on total arsenic,

because drinking water contains almost

entirely inorganic forms, and the

analytical methods for total arsenic are

readily available and capable of being

performed by certified laboratories at an

affordable cost.

E. Will There be a Health Advisory?

A health advisory for arsenic is not

part of today’s rulemaking. EPA will be

considering whether or not to issue a

health advisory after evaluating the

recommendations of the Science

Advisory Board (SAB) (EPA, 2000q).

The purpose of an advisory would be to

provide useful information to water

providers between issuance and

implementation of this rule.

F. What are the Best Available

Technologies For Removing Arsenic

From Drinking Water?

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

Drinking Water Act states that each

National Primary Drinking Water

Regulation (NPDWR) which establishes

an MCL shall list the technology,

treatment techniques, and other means

that 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:

(1) The capability of a high removal

efficiency;

(2) A history of full-scale operation;

(3) General geographic applicability;

(4) Reasonable cost based on large and

metropolitan water systems;

(5) Reasonable service life;

(6) Compatibility with other water

treatment processes; and

(7) The ability to bring all of the water

in a system into compliance.

EPA identified BATs in this section

using the listed criteria. Their removal

efficiencies and a brief discussion of the

major issues surrounding the usage of

each technology are also given in this

section. More details about the

treatment technologies and costs can be

found in ‘‘Technologies and Costs for

the Removal of Arsenic From Drinking

Water’’ (EPA, 2000t).

1. BAT technologies

EPA reviewed several technologies as

BAT candidates for arsenic removal,

e.g., 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 determined

that, of the technologies capable of

removing arsenic from source water,

only the technologies in Table I.F–1

fulfill the requirements of SDWA for

BAT determinations for arsenic. The

maximum percent of arsenic removal

that can be reasonably obtained from

these technologies is also shown in the

table. These removal efficiencies are for

arsenic (V) removal.

TABLE I.F–1.— BEST AVAILABLE

TECHNOLOGIES AND REMOVAL RATES

Treatment Technology

Maximum

Percent Removal 1

Ion Exchange (sulfate ≤ 50 mg/

L) ........................................... 95

Activated Alumina ..................... 95

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

Modified Coagulation/Filtration 95

Modified Lime Softening (pH >

10.5) ...................................... 90

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

Oxidation/Filtration (20:1

iron:arsenic) .......................... 80

1The percent removal figures are for arsenic (V) removal. Pre-oxidation may be

required.

2. Preoxidation

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 minus; and H2AsO4

2 minus;)

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, preoxidation to the As (V) species is

necessary.

As (III) may be converted through preoxidation 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 byproducts 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 POU and POE

devices, central chlorination may be

required for oxidation of As (III).

3. Factors affecting listing technologies

Ion Exchange (IX) can effectively

remove arsenic using anion exchange

resins. It is recommended as a BAT

primarily for sites with low sulfate

because sulfate is preferred over arsenic.

Sulfate will compete for binding sites

resulting in shorter run lengths. Due to

much shorter run lengths than activated

alumina, anion exchange must be

6982 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

regenerated because it is not cost

effective to dispose of the resin after one

use. Column bed regeneration frequency

is a key factor in the cost of the process

and affects the volume of waste

produced by the process. The proposed

rule preamble noted that anion

exchange may be practical up to

approximately 120 mg/L of sulfate

(Clifford, 1994). The upper-bound

sulfate concentration for the final rule is

50 mg/L. The selection of this upper

bound is based on several factors,

including cost and the ability to dispose

of the brine stream.

The proposed rule listed three

mechanisms to dispose of the brine

stream used for regeneration. The

options were: sanitary sewer,

evaporation pond, and chemical

precipitation. Many comments on the

proposed rule were based on the

assumption that the waste streams

generated would be considered

hazardous waste. Waste streams

containing less than 0.5% solids are

evaluated against the toxicity

characteristic directly to determine if

the waste is hazardous. Arsenic in the

regeneration brine will likely exceed 5

mg/L for most systems with arsenic

above 10 μg/L and sulfate below 50 mg/

L. Since the brine stream would likely

be considered hazardous, EPA

eliminated the evaporation pond and

the chemical precipitation options from

the decision tree as options for disposal

of anion exchange wastes. The Agency

retained discharge to a sanitary sewer

because domestic sewage and any

mixture of domestic sewage and other

wastes that pass through a sewer system

to a publicly owned treatment works

(POTW) for treatment is excluded from

consideration as solid waste (40 CFR

261.4). Domestic sewage means

untreated sanitary wastes that pass

through a sewage system. Discharges

meeting the previously stated criteria

are excluded from regulation as

hazardous waste. However, these

assumptions were reviewed to

substantially reduce projections of brine

wastes going to POTWs from those that

were used in support of the proposed

rule.

Discharge to a sanitary sewer can be

limited by technically based local limits

(TBLLs) for arsenic or total dissolved

solids. Since anion exchange is

regenerated more frequently than

activated alumina, the total dissolved

solids increase can be significant. Many

comments indicated that significant

increases in total dissolved solids would

be unacceptable, especially in the

Southwest where water resources are

scarce. Salt is used for regeneration of

anion exchange resins. The upper

bound of 50 mg/L sulfate for anion

exchange is based on projected

increases of total dissolved solids using

the quantity of salt needed for

regeneration and the frequency of

regeneration (based on sulfate). The

sulfate upper bound for the final rule is

significantly lower than the upper

bound from the proposed rule. Due to

the potential for an increase in total

dissolved solids, anion exchange would

be favored in areas other than the

Southwest where the volume of brine is

very small relative to the total volume

of wastewater being treated at the

POTW. Systems that need to treat only

a few entry points or can blend a

significant portion of the water to meet

the MCL may produce a smaller brine

stream to allow the brine to be

discharged to a POTW. Water systems

should check with the POTW to ensure

that the brine stream will be accepted

before selecting this option.

Activated Alumina (AA) is an

effective arsenic removal technology;

however, the capacity of activated

alumina to remove arsenic is very pH

sensitive. High removals can be

achieved over a broad range of pH, but

shorter run lengths will be observed at

higher pH. Activated alumina can be

operated in one of two ways. The

activated alumina can either be

disposed of or regenerated after the

media is exhausted. Under the

regeneration option, strong acids and

bases are used to remove arsenic from

the media so that it can be used again

to remove arsenic. Because arsenic is

strongly adsorbed to the media, only

about 50–70% of the adsorbed arsenic is

removed. The brine stream produced by

the regeneration process then requires

disposal. The proposed rule listed

discharge to a sanitary sewer as the

disposal mechanism for the brines.

Many comments on the proposed rule

noted that TBLLs for arsenic or total

dissolved solids might restrict discharge

of brine streams to the sanitary sewer.

Since activated alumina run lengths

(i.e., number of bed volumes (BV) per

run) are much longer than anion

exchange, the arsenic concentrations in

the brine stream would likely be much

higher. Regeneration of activated

alumina media is not recommended for

larger systems because: (1) Disposal of

the brine may be difficult, (2) the

regeneration process is incomplete

which reduces subsequent run lengths,

and (3) for most systems it will be

cheaper to replace the media rather than

regenerate it. The option of replacing

the spent media with new media is

called disposable activated alumina.

The disposable activated alumina

option can be operated both at the

optimal pH of 6 and at higher natural

water pH values. It is expected that

larger systems would adjust pH to take

advantage of the longer run lengths.

EPA developed several disposable

activated alumina options for the final

rule. Two options were based on

operating the process at the natural pH

of the water (no pH adjustment). These

options are intended primarily for

smaller systems, although larger systems

may also be able to operate at the

natural pH if it is low enough to get

sufficiently long run lengths. Two

options where the pH was adjusted to

pH 6 were also examined. The longer

run length is based on using sulfuric

acid to lower the pH. However, sulfate

can compete for adsorption sites with

arsenic. It was recommended that

hydrochloric acid be used to obtain a

longer run length (Clifford et al., 1998).

When pH is adjusted to pH 6, posttreatment corrosion control will be

necessary.

In our analysis, we assumed that

spent media could be safely disposed of

in a non-hazardous landfill. The

preamble to the proposed rule described

results from testing of activated alumina

media used to remove arsenic in

drinking water systems with arsenic

above 50 μg/L. The results from the

Toxicity Characteristic Leaching

Procedure (TCLP) on these samples was

typically less that 50 μg/L. 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 (5000 μg/L) and is listed in 40

CFR 261.24(a). The TC regulatory level

is one hundred times higher than the

results from the activated alumina

samples.

Reverse Osmosis (RO) can provide

removal efficiencies of greater than 95%

when operating pressure is ideal. Water

rejection (on the order of 20–25%) may

be an issue in water-scarce regions and

may prompt systems employing RO to

seek greater levels of water recovery.

Water recovery is the volume of

drinking water produced by the process

divided by the influent stream (product

water/influent stream). Increased water

recovery is often more expensive, since

it can involve recycling of water through

treatment units to allow more efficient

separation of solids from water. This

can also produce more concentrated

solid wastes. However, the waste stream

will generally not be as concentrated as

anion exchange brines, so it should be

easier to dispose of. Based on the cost

of the process, it is unlikely that reverse

osmosis would be installed solely for

arsenic removal. Blending a treated

portion with an untreated portion and

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 6983

still meeting the MCL would make

reverse osmosis more cost effective. If

blending is not an option, posttreatment corrosion control would be

necessary. Since a large portion of the

water is wasted, water quantity could be

an issue, especially in the Western U.S.

It should be noted that while reverse

osmosis is listed as a BAT, it was not

used to develop national costs because

other options are more cost effective and

have much smaller waste streams.

Modified Coagulation/Filtration (C/F)

is an effective treatment process for

removal of As (V) according to

laboratory, pilot-plant, and full-scale

tests. The type of coagulant and dosage

used affects the efficiency of the

process. 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. Systems may

need to lower pH or add more coagulant

to achieve higher removals.

Modified Lime Softening (LS),

operated within the optimum pH range

of greater than 10.5 is likely to provide

a high percentage of As removal.

Systems operating lime softening at

lower pH will need to increase the pH

to achieve higher removals of arsenic.

Coagulation/Filtration and Lime

Softening are unlikely to be installed

solely for arsenic removal. Systems

considering installation of one of these

technologies should design the process

to operate in the optimal pH range if

high removal efficiencies are needed for

compliance.

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 and typically

operates at a recovery of 70 to 80%.

Since a large portion of the water is

wasted, water quantity could be an

issue, especially in the Western U.S. It

should be noted that while

electrodialysis reversal is listed as a

BAT, it was not used to develop

national costs because other options are

more cost effective and have much

smaller waste streams.

Oxidation/Filtration (including

greensand filtration) has an advantage in

that there is not as much competition

with other ions. Arsenic is coprecipitated with the iron during iron

removal. Sufficient iron needs to be

present to achieve high arsenic

removals. One study recommended a

20:1 iron to arsenic ratio (Subramanian

et al., 1997). Removals of approximately

80% were achieved when iron to

arsenic ratio was 20:1. When the iron to

arsenic ratio was lower (7:1), removals

decreased below 50%. 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. When the arsenic is present as

As(III), sufficient contact time needs to

be provided to convert the As(III) to

As(V) for removal by the oxidation/

filtration process. An additional preoxidation step is not required for this

process as long as there is sufficient

contact time. In developing national

cost estimates, EPA assumed that

systems would opt for this type of

technology only if more than 300 μg/L

of iron was present. The Agency

assumed a removal percentage of 50%

when estimating national costs because

the 20:1 ratio could not be verified due

to limitations in the co-occurrence

database. However, EPA assumed a

removal percentage of 80% as part of a

sensitivity analysis. At proposal EPA

indicated that oxidation filtration was

not being listed as BAT because it has

a low removal efficiency, which might

not be appropriate for an MCL of 5.

However, the Agency also noted that

this technology may be appropriate for

systems that do not require high arsenic

removal and had high iron in their

source water. Because this is an

inexpensive technology that is

particularly effective for high-iron, lowarsenic waters, EPA is listing oxidation/

filtration as a BAT with a footnote that

the iron-to-arsenic ratio must be at least

20:1. Systems with greater than 300 μg/

L of iron will also see benefits in the

aesthetic quality of the water as the iron

can be reduced below the secondary

standard. EPA’s inclusion of oxidation/

filtration as a BAT in today’s final rule

is based upon further evaluation of all

available information and studies as

well as on public comments.

4. Other technologies evaluated, but not

designated as BAT

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 that are consistently

below 2 μg/L. Critical operating

parameters are iron dose, mixing energy,

detention time, and pH (Clifford, 1997).

Coagulation and microfiltration as

separate processes have both been

installed full scale, but the combined

coagulation/microfiltration process does

not have a full-scale operation history.

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. EPA

used this option in developing the

national cost estimate because we

believe coagulation/microfiltration is an

appropriate technology that will be used

by certain water systems to comply with

this rule, even though it is not currently

listed as BAT for the reasons mentioned.

Granular ferric hydroxide is a

technology that may combine very long

run length without the need to adjust

pH. The technology has been

demonstrated for arsenic removal full

scale in England (Simms et al., 2000). A

pilot-scale study for activated alumina

was also conducted on that water and

showed run lengths much longer than

observed in pilot-scale studies in the

United States. Due to the lack of

published data showing performance for

a range of water qualities, granular ferric

hydroxide was not designated a BAT. In

addition, there is little published

information on the cost of the media, so

it is difficult to evaluate cost. Granular

ferric hydroxide is being investigated in

several ongoing studies and may be an

effective technology for removing

arsenic. Systems may wish to

investigate it and other adsorption

technologies such as modified activated

alumina and other iron-based media.

Many of these other new adsorptive

media are also being investigated in

several ongoing studies.

5. Waste disposal

Waste disposal will be an important

issue for both large and small drinking

water plants. Costs for waste disposal

have been added to the costs of the

treatment technologies (in addition to

any pre-oxidation and corrosion control

costs), and form part of the treatment

trains that are listed in Tables I.G–1,

I.G–5, and I.G–6.

The preamble to the proposed rule

summarized toxicity characteristic

leaching procedure (TCLP) data on

residuals from different arsenic removal

6984 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

technologies. The arsenic

concentrations in TCLP extracts from

alum coagulation, activated alumina,

lime softening, iron/manganese

removal, and coagulation-microfiltration

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 were

mixed—the residuals from an arsenic

removal plant were below 0.05 mg/L,

but the residuals from another iron

coagulation plant were above 1 mg/L.

However, this is still below the TC

regulatory level of 5 mg/L. Based on

these 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. Options where the

brine stream could be hazardous were

eliminated from the final decision tree.

For the purposes of the national cost

estimate, it was assumed that solid

residuals would be disposed of at

nonhazardous landfills.

G. Treatment Trains Considered For

Small Systems

1. Can my water system use point-of-use

(POU), point-of-entry (POE), or bottled

water to comply with this regulation?

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 or equal to

500; (2) population of more than 500,

but less than or equal to 3,300; and (3)

population of more than 3,300, but less

than or equal to 10,000. Owners and

operators may choose any technology or

technique that best suits their

conditions, as long as the MCL is met.

The technologies examined for BAT

determinations were also evaluated as

small system compliance technologies.

Several other alternatives that are solely

small system options were also

evaluated as compliance technologies.

Central treatment is not the only option

available to small systems. One of the

provisions included in the SDWA

Amendments of 1996 allows the use of

POU and POE devices as compliance

technologies for small systems. 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 maintenance

and compliance with the MCL or treatment

technique and equipped with mechanical

warnings to ensure that customers are

automatically notified of operational

problems (§ 1412(b)(4)(E)).

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

such as at many NTNCWSs. 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. However, there will

be higher administrative costs

associated with POU and POE options.

For POU options, the trade-off is lower

treatment cost since only 1% of the

water is treated, but higher

administrative and monitoring costs

occur. Centrally managed POU options,

even with the higher monitoring and

administrative costs, are less expensive

than central treatment for populations

up to 150 to 250 people depending upon

the technology and number of

households.

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 may

require special regulations regarding

customer responsibilities as well as

water utility responsibilities. The water

system or person under contract to the

system is responsible for maintaining

the devices in customers’ homes. This

responsibility cannot be delegated to the

customer. Use of POU/POE systems

does not reduce the need for a wellmaintained water distribution system.

Increased monitoring may be necessary

to ensure that the treatment units are

operating properly. Monitoring POU/

POE systems is also more complex

because compliance samples need to be

taken after each POU or POE unit rather

than at the entry point to the

distribution system to be reflective of

treatment.

EPA examined three technologies as

POU and POE devices for the proposed

rule. EPA assumed that systems would

more likely choose to use POU activated

alumina (AA) or reverse osmosis (RO),

and POE AA in the proposed rule. POU

and POE ion exchange (IX) and POE RO

were considered, but not included as

compliance technologies in the

proposed rule. Activated alumina and

ion exchange units face a breakthrough

issue. If the activated alumina is not

replaced on time, there is a potential for

significantly reduced arsenic removal.

However, if the anion exchange resin is

not replaced or regenerated on time, the

previously removed arsenic can be

driven off the resin by sulfate. Tap water

arsenic concentrations can be higher

than the source water. This is called

chromatographic peaking. Due to the

potential for chromatographic peaking

and run lengths that would typically be

less than six months, anion exchange

was not listed as a compliance

technology in the proposed rule. POE

ion exchange also may present problems

with total dissolved solids since the

resin would need to be regenerated.

Since all sites within the system would

need treatment, the total dissolved

solids increase from a centrally

managed POE ion exchange system

would be similar to that from a central

treatment ion exchange system. EPA did

not list POE RO units as compliance

technologies because it could create

corrosion control problems. In addition,

water recovery would be no higher than

central treatment, so water quantity

issues associated with central treatment

reverse osmosis would be applicable to

POE RO.

The proposed rule included POE AA

as a small system compliance

technology. Arsenic removal by AA is

very sensitive to the pH. The finished

water pH will typically be higher than

the optimal pH of 6 to meet the

corrosion control requirements of the

lead and copper rule. A finished water

pH for many systems would be in the

range of pH 7 to pH 8. Using data on

activated alumina run length and pH, it

was determined that viable run lengths

were likely only when the finished

water pH was at or below pH 7.5

(Kempic, 2000). Even in this pH range,

the media may need to be replaced more

frequently than once a year, which

would make the option very expensive

especially compared to the POU AA

option. The run length data used for this

analysis were from a site with very little

competing ions (Simms and Azizian,

1997). Studies at other sites with higher

levels of competing ions have much

lower run lengths (Clifford et al., 1998).

Based on the limited finished water pH

range where POE AA might be effective

and the fact that the POU media needs

replacing much less frequently due to

lower water demand, POE AA has not

been listed as a compliance technology

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 6985

in the final rule. POE devices utilizing

media that are less sensitive to pH

adjustment may be listed as compliance

technologies in the future once data on

their performance are generated.

The effect of pH was also examined

on POU AA. Under the POU AA option,

the volume of water requiring treatment

is much smaller. The unit will be

installed at the kitchen tap and only the

water being used for cooking and

consumption is being treated for arsenic

removal. Since the ratio of the daily

volume of water being treated to the size

of the unit is much smaller, POU units

can be operated for longer periods of

time before the media needs to be

replaced. The replacement frequency

assumed for the costs is every six

months. Viable run lengths for the POU

option were greater than one year up to

pH 8 (Kempic, 2000). This analysis

assumed a large daily usage volume of

24 liters per day. The average

consumption per person per day is just

over 1 liter. Even if competing ions

reduced the run length significantly,

systems with tap water at or below pH

8 should meet the MCL of 10 μg/L using

a six-month replacement frequency for

the media. POU AA is a compliance

technology when the tap water pH is at

or below pH 8.

POU RO was listed as a compliance

technology in the proposed rule and it

is being listed as a compliance

technology in the final rule as well.

Several comments indicated that water

rejection would be an issue with POU

devices. Since only about 1% of the

total water used in the household is

being treated, POU RO is unlikely to

create water quantity problems. If the

water rejection rate was 10:1, this would

only increase the total household water

demand by about 10 percent. Where

availability of additional water is

limited, systems may want to consider

other alternatives to meet the MCL.

In order to be consistent with 1996

SDWA Amendments, EPA issued a

Federal Register notice on June 11, 1998

(EPA, 1998f) that deleted the

prohibition on the use of POU devices

as compliance technologies. This

prohibition was in 40 CFR 141.101. This

section now states that public water

systems shall not use bottled water to

achieve compliance with an MCL.

Bottled water may be used on a

temporary basis to avoid unreasonable

risk to health. Therefore, bottled water

cannot be used as a compliance

technology for the arsenic rule.

Likely treatment trains are shown in

Table I.G–1. These trains represent a

wide variety of solutions, including

BATs, that small systems 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, preoxidation and corrosion control. While

systems could install lime softening at

pH > 10.5 or optimized coagulation/

filtration solely for arsenic removal,

EPA does not view this as a likely

option. Reverse osmosis and

electrodialysis reversal are also not

included in this table because other

options are more cost effective for

arsenic removal and do not reject a large

volume of water like these two

technologies. RO and EDR may be costeffective options if removal of other

contaminants is needed and water

quantity is not a concern.

TABLE I.G–1.— TREATMENT TECHNOLOGY TRAINS FOR CONSIDERATION BY SMALL SYSTEMS IN COMPLYING WITH FINAL

RULE INCLUDING BATS

Train # Treatment Technology Trains for Consideration by Small Systems

1 ........................ Add pre-oxidation [if not in-place] and modify in-place Lime Softening (pH > 10.5) and modify corrosion control.

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

3 ........................ Add pre-oxidation [if not in-place] and add Anion Exchange and add POTW waste disposal. Sulfate level ≤ 20 mg/L.

4 ........................ Add pre-oxidation [if not in-place] and add Anion Exchange and add POTW waste disposal. Sulfate level: 20 mg/L < sulfate ≤

50 mg/L.

5 ........................ Add pre-oxidation [if not in-place] and add Coagulation Assisted Microfiltration with corrosion control and add mechanical

dewatering/non-hazardous landfill waste disposal.

6 ........................ Add pre-oxidation [if not in-place] and add Coagulation Assisted Microfiltration with corrosion control and add non-mechanical

dewatering/non-hazardous landfill waste disposal.

7 ........................ Add Oxidation/Filtration (Greensand) (20:1 iron: arsenic) and add POTW for backwash stream.

8 ........................ Add pre-oxidation [if not in-place] and add Activated Alumina and add non-hazardous landfill (for spent media) waste disposal. pH 7 ≤ pH < pH 8.

9 ........................ Add pre-oxidation [if not in-place] and add Activated Alumina and add non-hazardous landfill (for spent media) waste disposal. pH 8 ≤ pH ≤ pH 8.3.

10 ...................... Add pre-oxidation [if not in-place] and add Activated Alumina with pH adjustment (to pH 6) and corrosion control and add

non-hazardous landfill (for spent media) waste disposal. Run length = 23,100 BV.

11 ...................... Add pre-oxidation [if not in-place] and add Activated Alumina with pH adjustment (to pH 6) and corrosion control and add

non-hazardous landfill (for spent media) waste disposal. Run length = 15,400 BV.

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

13 ...................... Add pre-oxidation [if not in-place] and add POU Activated Alumina. (Finished water pH ≤ pH 8.0)

Pre-oxidation costs are given as a

separate component because they will

be incurred only by some systems. In

estimating national costs, it was

assumed that only systems without preoxidation in place would need to add

the necessary equipment. It is expected

that no surface water systems will need

to install pre-oxidation for arsenic

removal and 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 ascertain if preoxidation is necessary by determining if

the arsenic is present as As (III) or As

(V). Ground water systems with

predominantly As (V) will probably not

need pre-oxidation to meet the MCL.

2. What are the affordable treatment

technologies for small systems?

The 13 treatment trains listed in Table

I.G–1 were compared against the

national-level affordability criteria to

determine the affordable treatment

trains. The Agency’s national-level

affordability criteria were published in

the August 6, 1998 Federal Register

(EPA, 1998h). In this notice, EPA

discussed the procedure for affordable

6986 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

treatment technology determinations for

the contaminants regulated before 1996.

The preamble to the proposed arsenic

rule described the derivation of the

national-level affordability criteria (65

FR 38888 at 38926; EPA, 2000i). A very

brief summary follows: First an

‘‘affordability threshold’’ (i.e., the total

annual household water bill that would

be considered affordable) was

calculated. The total annual water bill

includes costs associated with water

treatment, water distribution, and

operation of the water system. In

developing the threshold of 2.5%

median household income, EPA

considered the percentage of median

household income spent by an average

household on comparable goods and

services and on cost comparisons with

other risk reduction activities for

drinking water such as households

purchasing bottled water or a home

treatment device. 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’’

(EPA, 1998l).

The Variance Technology Findings

document also describes the derivation

of the baselines for median household

income, annual water bills, and annual

household consumption. Data from the

Community Water System Survey

(CWSS) were used to derive the annual

water bills and annual water

consumption values for each of the

three small system size categories. The

Community Water System Survey data

on zip codes were used with the 1990

Census data on median household

income to develop the median

household income values for each of the

three small-system size categories. The

median household-income values used

for the affordable technology

determinations are not based on the

national median income. The value for

each size category is a national median

income for communities served by small

water systems within that range. Table

I.G–2 presents the baseline values for

each of the three small-system size

categories. Annual water bills and

median household income are based on

1995 estimates.

TABLE I.G–2.—BASELINE VALUES FOR SMALL SYSTEMS CATEGORIES

System size category

(population served)

Annual household consumption

(1000 gallons/yr)

Annual water bills

($/yr)

Median household income

($)

25–500 ......................................................................................... 72 $211 $30,785

501–3,300 .................................................................................... 74 184 27,058

3,300–10,000 ............................................................................... 77 181 27,641

For each size category, the threshold

value was determined by multiplying

the median household income by 2.5%.

The annual household water bills were

subtracted from this value to obtain the

available expenditure margin. Projected

treatment costs will be compared

against the available expenditure margin

to determine if there are affordable

compliance technologies for each size

category. The available expenditure

margin for the three size categories is

presented in Table I.G–3.

TABLE I.G–3.—AVAILABLE EXPENDITURE MARGIN FOR AFFORDABLE

TECHNOLOGY DETERMINATIONS

System size category

(population

served)

Available expenditure

margin

($/household/year)

25–500 .............. 559

501–3,300 ......... 492

3,301–10,000 .... 510

The size categories specified in

SDWA for affordable technology

determinations are different than the

size categories typically used by EPA in

the Economic Analysis. A weighted

average procedure was used to derive

design and average flows for the 25–500

category using design and average flows

from the 25–100 and 101–500

categories. A similar approach was used

to derive design and average flows from

the 501–1000 and 1001–3300 categories

for the 501–3300 category. The Variance

Technology Findings document (EPA,

1998l) describes this procedure in more

detail. Table I.G–4 lists the design and

average flows for the three size

categories.

TABLE I.G–4.— DESIGN AND AVERAGE DAILY FLOWS USED FOR AFFORDABLE TECHNOLOGY DETERMINATIONS

System size category

(population served)

Design flow

(mgd)

Average flow

(mgd)

25–500 ......................................................................................................................................................... 0.058 0.015

501–3,300 .................................................................................................................................................... 0.50 0.17

3,301–10,000 ............................................................................................................................................... 1.8 0.70

Capital and operating and

maintenance costs were derived for each

treatment train using the flows listed

previously and the cost equations in the

Technology and Cost Document. Several

conservative assumptions were made to

derive the costs. The influent arsenic

concentration was assumed to be 50 μg/

L, which was the MCL for arsenic prior

to this rule. The treatment target was 8

μg/L, which is 80% of the MCL. Thus,

little blending could be performed to

reduce costs. Capital costs were

amortized using the 7% interest rate

preferred by OMB for benefit-cost

analyses of government programs and

regulations rather than a 3% interest

rate.

The annual system treatment cost in

dollars per year was converted into a

rate increase using the average daily

flow. The annual water consumption

values listed in Table I.G–2 were

multiplied by 1.15 to account for water

lost due to leaks. Since the water lost to

leaks is not billed, the water bills for the

actual water used were adjusted to cover

this lost water by increasing the

household consumption. The rate

increase in dollars per thousand gallons

used was multiplied by the adjusted

annual consumption to determine the

annual cost increase for the household

for each treatment train. Several

comments on affordability presented

household cost increases that were

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 6987

derived by dividing the annual system

cost by the number of households. That

is an inappropriate method because

residential customers would not only be

paying for the water that they use, but

also all the water used by nonresidential customers of the system..

Of the 13 treatment trains in Table

I.G–1, the ones identified in Table I.G–

5 are deemed to be affordable for

systems serving 25–500 people as the

annual household cost was below the

available expenditure margin. The two

trains using coagulation-assisted

microfiltration are not affordable for this

size category. All 13 treatment trains are

deemed to be affordable for systems

serving 501–3,300 and 3,301–10,000

people and are presented in Table I.G–

6. 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, POU and POE

devices are also compliance technology

options for the smaller systems.

TABLE I.G–5.— AFFORDABLE COMPLIANCE TECHNOLOGY TRAINS FOR SMALL SYSTEMS WITH POPULATION 25–500

Train No. Treatment Technology Trains

1 ........................ Add pre-oxidation [if not in-place] and modify in-place Lime Softening (pH > 10.5) and modify corrosion control.

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

3 ........................ Add pre-oxidation [if not in-place] and add Anion Exchange and add POTW waste disposal. Sulfate level ≤ 20 mg/L.

4 ........................ Add pre-oxidation [if not in-place] and add Anion Exchange and add POTW waste disposal. Sulfate level: 20 mg/L < sulfate ≤

50 mg/l.

7 ........................ Add Oxidation/Filtration (Greensand) (20:1 iron: arsenic) and add POTW for backwash stream.

8 ........................ Add pre-oxidation [if not in-place] and add Activated Alumina and add non-hazardous landfill (for spent media) waste disposal. pH 7 ≤pH < pH 8.

9 ........................ Add pre-oxidation [if not in-place] and add Activated Alumina and add non-hazardous landfill (for spent media) waste disposal. pH 8 ≤ pH ≤ pH 8.3.

10 ...................... Add pre-oxidation [if not in-place] and add Activated Alumina with pH adjustment (to pH 6) and corrosion control and add

non-hazardous landfill (for spent media) waste disposal. Run length = 23,100 BV.

11 ...................... Add pre-oxidation [if not in-place] and add Activated Alumina with pH adjustment (to pH 6) and corrosion control and add

non-hazardous landfill (for spent media) waste disposal. Run length = 15,400 BV.

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

13 ...................... Add pre-oxidation [if not in-place] and add POU Activated Alumina. (Finished water pH ≤ pH 8.0)

TABLE I.G–6.— AFFORDABLE COMPLIANCE TECHNOLOGY TRAINS FOR SMALL SYSTEMS WITH POPULATIONS 501–3,300

AND 3,301 TO 10,000

Train No. Treatment Technology Trains

1 ........................ Add pre-oxidation [if not in-place] and modify in-place Lime Softening (pH > 10.5) and modify corrosion control.

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

3 ........................ Add pre-oxidation [if not in-place] and add Anion Exchange and add POTW waste disposal. Sulfate level ≤ 20 mg/L.

4 ........................ Add pre-oxidation [if not in-place] and add Anion Exchange and add POTW waste disposal. Sulfate level: 20 mg/L < sulfate ≤

50 mg/l.

5 ........................ Add pre-oxidation [if not in-place] and add Coagulation Assisted Microfiltration with corrosion control and add mechanical

dewatering/non-hazardous landfill waste disposal.

6 ........................ Add pre-oxidation [if not in-place] and add Coagulation Assisted Microfiltration with corrosion control and add non-mechanical

dewatering/non-hazardous landfill waste disposal.

7 ........................ Add Oxidation/Filtration (Greensand) (20:1 iron: arsenic) and add POTW for backwash stream.

8 ........................ Add pre-oxidation [if not in-place] and add Activated Alumina and add non-hazardous landfill (for spent media) waste disposal. pH 7 ≤pH < pH 8.

9 ........................ Add pre-oxidation [if not in-place] and add Activated Alumina and add non-hazardous landfill (for spent media) waste disposal. pH 8 ≤ pH ≤ pH 8.3.

10 ...................... Add pre-oxidation [if not in-place] and add Activated Alumina with pH adjustment (to pH 6) and corrosion control and add

non-hazardous landfill (for spent media) waste disposal. Run length = 23,100 BV.

11 ...................... Add pre-oxidation [if not in-place] and add Activated Alumina with pH adjustment (to pH 6) and corrosion control and add

non-hazardous landfill (for spent media) waste disposal. Run length = 15,400 BV.

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

13 ...................... Add pre-oxidation [if not in-place] and add POU Activated Alumina. (Finished water pH ≤ pH 8.0)

3. Can My Water System Get a Small

System Variance From an MCL Under

Today’s Rule?

Section 1415(e)(1) of SDWA allows

States to grant variances to small water

systems (i.e., systems having 10,000

customers or less) 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.

EPA has determined that affordable

technologies exist for all three system

size categories and has therefore not

identified a variance technology for any

system size or source water quality

combination. Small system variances

are not available for the final arsenic

MCL.

H. Can My System Get a General

Variance or Exemption From the MCL

Under Today’s Rule?

General variances may be granted in

accordance with section 1415(a)(1)(A) of

SDWA and EPA’s regulations. General

variances are available to public water

systems that have installed or agree to

install the BAT but, due to source water

quality, are or will be unable to comply

with the national primary drinking

water standard. The general variance

6988 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

provisions of SDWA are narrowly

focused on addressing those rare

circumstances where some unusual

characteristic of the source water

available to a system will result in less

effective performance of the BAT.

Exemptions may be granted in

accordance with section 1416(a) of

SDWA and EPA’s regulations.

Exemptions are designed to provide a

system facing compelling

circumstances, such as economic

hardship, additional time to come into

compliance.

Under section 1415(a)(1)(A) of the

SDWA, a State that has primary

enforcement responsibility (primacy), or

EPA as the primacy agency, may grant

variances from MCLs to those public

water systems of any size that cannot

comply with the MCLs because of

characteristics of the water sources. The

primacy agency may grant general

variances to a system on condition that

the system install the best available

technology, treatment techniques, or

other means, and provided that

alternative sources of water are not

reasonably available to the system. At

the time this type of variance is granted,

the State must prescribe a schedule for

compliance with its terms and may

require the system to implement

additional control measures.

Furthermore, before EPA or the State

may grant a general variance, it must

find that the variance will not result in

an unreasonable risk to health (URTH)

to the public served by the public water

system.

Under section 1413(a)(4), States that

choose to issue general variances must

do so under conditions, and in a

manner, that are no less stringent than

section 1415. Of course, a State may

adopt standards that are more stringent

than the EPA’s standards. EPA specifies

BATs for general variance purposes.

EPA may identify as BAT different

treatments under section 1415 for

variances other than the BAT under

section 1412 for MCLs. The BAT

findings for section 1415 may vary

depending on a number of factors,

including the number of persons served

by the public water system, physical

conditions related to engineering

feasibility, and the costs of compliance

with MCLs. In this final rule, EPA is not

specifying different BAT for variances

under section 1415(a).

Under section 1416(a), EPA or a State

may exempt a public water system from

any requirements related to an MCL or

treatment technique of an NPDWR if it

finds that: (1) Due to compelling factors

(which may include a variety of

‘‘compelling’’ factors, including

economic factors such as qualification

of the PWS as serving a disadvantaged

community), the PWS is unable to

comply with the requirement or

implement measure to develop an

alternative source of water supply; (2)

the exemption will not result in an

URTH; (3) the PWS was in operation on

the effective date of the NPWDR, or for

a system that was not in operation by

that date, only if no reasonable

alternative source of drinking water is

available to the new system; and (4)

management or restructuring changes

(or both) cannot reasonably result in

compliance with the Act or improve the

quality of drinking water.

If EPA or the State grants an

exemption to a public water system, it

must at the same time prescribe a

schedule for compliance (including

increments of progress or measures to

develop an alternative source of water

supply) and implementation of

appropriate control measures that the

State requires the system to meet while

the exemption is in effect. Under section

1416(b)(2)(A), the schedule prescribed

shall require compliance as

expeditiously as practicable (to be

determined by the State), but no later

than 3 years after the compliance date

for the regulations established pursuant

to section 1412(b)(10). For public water

systems serving 3,300 people or less and

needing financial assistance for the

necessary improvements, EPA or the

State may renew an exemption for one

or more additional two-year periods, but

not to exceed a total of six years, if the

system establishes that it is taking all

practicable steps to meet certain

requirements specified in the statute.

Thus, the maximum possible duration

of a small systems exemption is nine

years beyond the 5-year compliance

schedule specified in today’s rule.

A public water system shall not be

granted an exemption unless it can

establish that either: (1) The system

cannot meet the standard without

capital improvements that cannot be

completed prior to the date established

pursuant to section 1412(b)(10); (2) in

the case of a system that needs financial

assistance for the necessary

implementation, the system has entered

into an agreement to obtain financial

assistance pursuant to section 1452 or

any other Federal or State program; or

(3) the system has entered into an

enforceable agreement to become part of

a regional public water system.

EPA believes that exemptions will be

an important tool to help States address

the number of systems needing financial

assistance to achieve compliance with

the arsenic rule (and other rules) with

the available supply of financial

assistance. About 2,300 CWSs and about

1,100 NTNCWSs will need to install

treatment to achieve compliance with

today’s final rule. CWSs and not-forprofit NTNCWSs are eligible for

assistance from the Drinking Water State

Revolving Fund (DWSRF). Between its

inception in Federal Fiscal Year 1997

and June 2000, the DWSRF program has

provided assistance to about 1,100

systems. Given the many competing

demands being placed on financial

assistance programs, the ability to

extend the period of time available for

a system to receive financial assistance

will provide important flexibility for

States and systems. Exemptions provide

an opportunity to extend the period of

time during which a system can achieve

compliance, thus providing needy

systems with additional time to qualify

for financial assistance. Under today’s

action, all systems have 5 years to

achieve compliance. Exemptions for an

additional 3 years can be made available

to qualified systems. For those qualified

systems serving 3,300 persons or less,

up to 3 additional 2-year extensions to

the exemption are possible, for a total

exemption duration of 9 years. When

added to the 5 years provided for

compliance by the rule, this allows up

to 14 years for small systems serving up

to 3,300 people to achieve compliance.

EPA will issue guidance in the near

future on considerations involved in

granting exemptions under the arsenic

rule, including making findings of no

URTH where exemptions are offered.

I. What Analytical Methods are

Approved for Compliance Monitoring of

Arsenic and What are the Performance

Testing Criteria for Laboratory

Certification?

1. Approved Analytical Methods

Today’s rule lists four analytical

technologies that are approved for

compliance determinations of arsenic at

the MCL of 0.01 mg/L (see Table I.I–1).

As noted in the June 22, 2000 proposed

rule (65 FR 38888, EPA, 2000i), the

methods listed in Table I.I–1 are the

same analytical technologies that were

approved for arsenic when the MCL was

0.05 mg/L, with the exception of the

methods that use Inductively Coupled

Plasma Atomic Emission Spectroscopy

(ICP–AES) measurement technology.

EPA is withdrawing two ICP–AES

methods (EPA Method 200.7 and SM

3120B) because their detection limits

(0.008 mg/L and 0.050 mg/L

respectively) are too high to reliably

determine compliance with an MCL of

0.01 mg/L. In the June 2000 proposed

rule, EPA noted that the ICP–AES

methods were rarely used to obtain

laboratory certification when analyzing

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 6989

low level challenge samples for arsenic.

Therefore, we believe withdrawal of the

availability of the ICP–AES methods for

compliance determinations of arsenic in

drinking water will not affect laboratory

capacity. EPA did not receive any

adverse comment on the proposal to

withdraw approval of these two

methods, and today’s final rule amends

the CFR to effect this withdrawal.

TABLE I.I–1.—APPROVED ANALYTICAL METHODS (40 CFR 141.23) FOR ARSENIC AT THE MCL OF 0.01 MG/L

Methodology Reference method

Inductively Coupled Plasma Mass Spectroscopy (ICP–MS) .................................................................................................. 200.8 (EPA)

Stabilized Temperature Platform Graphite Furnace Atomic Absorption (STP–GFAA) ........................................................... 200.9 (EPA)

Graphite Furnace Atomic Absorption (GFAA) ......................................................................................................................... 3113B (SM) D–2972–

93C (ASTM)

Gaseous Hydride Atomic Absorption (GHAA) ......................................................................................................................... 3114B (SM) D–2972–

93B (ASTM)

2. Performance Testing Criteria for

Laboratory Certification

For purposes of drinking water

laboratory certification, the Agency

specifies pass/fail (acceptance) limits for

a successful analysis of the required

annual challenge sample, i.e., a

performance evaluation (PE) or

performance testing (PT) sample. These

acceptance limits have been historically

derived using one of two different

approaches:

(a) Variable acceptance limits uniquely

derived for each PE study from a regression

analysis of the performance of all laboratories

that participate in that PE-study, or

(b) Fixed acceptance limits derived from a

regression analysis of the laboratory PE

sample analysis results in several PE studies.

Variable acceptance limits are

analogous to ‘‘grading on a curve’’

which means that the pass/fail limit can

vary from PE study to study depending

on the quality and experience of the

laboratories participating in the study.

These limits are specified in the CFR as

plus or minus two sigma (2 ) where

sigma is the standard deviation of the

analytical results reported in the PE

study. EPA specifies variable acceptance

limits when a method or measurement

technology is new enough that an

insufficient number of experienced

laboratories have participated in the PE

studies or when only a few PE studies

have been conducted.

EPA prefers the fixed acceptance

limits approach because it is the better

indicator of laboratory performance

averaged over time and several different

concentrations of the target analyte.

Fixed limits also provide the same pass/

fail benchmark in each PE study. As

discussed in the proposed rule, EPA has

a large base of PE-study data from which

to derive a practical quantitation limit

(PQL) and a fixed PE-study acceptance

limit for arsenic. Thus, as proposed in

the June 2000 rule, today’s final rule

amends § 141.23(k)(3)(ii) to specify an

acceptance limit of ±30% in PE (now

known as PT) samples spiked with

arsenic at the PQL of 0.003 mg/L or

greater. For a brief discussion of the

derivation of the PQL for arsenic, see

section III.B.1, What is the feasible

level?

J. How Will I Know if My System Meets

the Arsenic Standard?

This section summarizes changes to

the arsenic monitoring and compliance

determination requirements. The

Agency is also changing the methods

used by a system to determine if it is in

violation of an MCL for all of the

regulated inorganic contaminants

(IOCs), synthetic organic contaminants

(SOCs), and volatile organic

contaminants (VOCs). See section I.J.3.

for more information regarding violation

determinations.

1. Sampling Points and Grandfathering

of Monitoring Data

In today’s rule, the Agency is moving

the requirements associated with

arsenic into § 141.23(c) making it

consistent with the requirements for

IOCs regulated under the standardized

monitoring framework. All CWS and

NTNCWSs must monitor for arsenic at

each entry point to the distribution

system. In some cases, § 142.11(1)

allows States to establish regulations

that ‘‘vary from comparable regulations

set forth in part 141 of this chapter, and

demonstrate that any different State

regulation is at least as stringent as the

comparable regulation contained in part

141.’’ Using this authority, States may

allow systems to collect samples at an

alternative location (e.g., the first point

of drinking water consumption in the

distribution system) if the State justifies

in its primacy program that the

alternative location is equally or more

protective. States could implement the

change in sampling location once the

primacy package is approved.

The MCL compliance elements of the

rule become effective in 2006. Some

ground water systems will collect

samples to comply with the sampling

requirements for all regulated IOCs

(including arsenic) in 2005 in

accordance with the State monitoring

plan. This sampling event will satisfy

the monitoring requirements for the

2005–2007 compliance period, but the

revised arsenic MCL will not become

effective until 2006. Ground water

systems may use grandfathered data

collected after January 1, 2005 to satisfy

the sampling requirements for the 2005–

2007 compliance period. The

grandfathered data must report results

from analytical methods approved for

use by this final rule (e.g., the method

detection limit must be substantially

less than the revised MCL of 10 μg/L).

Data collected using unacceptably high

detection levels (e.g. using ICP–AES

technology) will not be eligible for

grandfathering. If the grandfathered data

are used to comply with the 2005–2007

compliance period and the analytical

result is greater than 10 μg/L, that

system will be in violation of the

revised MCL on the effective date of the

rule. If systems do not use grandfathered

data, then surface water systems must

collect a sample by December 31, 2006

and ground water systems must collect

a sample by December 31, 2007 to

demonstrate compliance with the

revised MCL.

2. Compositing of Samples

Compositing of samples is allowed

under the standardized monitoring

framework. The States that allow

compositing of samples use the

methodology in the Phase II/V

regulations as specified in

§ 141.23(a)(4). In today’s rule, CWSs and

NTNCWSs will still be allowed to

composite samples; however, if arsenic

is detected above one-fifth of the revised

MCL (2 μg/L), then a follow-up sample

must be taken within 14 days at each

sampling point included in the

composite as described in § 141.23(a)(4).

Compliance determinations must be

based on the follow up sample result.

Water systems may composite samples

(temporally and spatially) until a

6990 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

contaminant (arsenic or any other

contaminant regulated in the Phase II/V

regulations) is detected. Once a

contaminant has been detected in a

composited sample at concentrations

greater than one-fifth of the MCL, the

system(s) must discontinue the practice

of compositing samples for all future

monitoring.

3. Calculation of Violations

In today’s rule, the Agency is

clarifying the compliance determination

section for the IOCs (including arsenic),

the SOCs, and the VOCs in §§ 141.23(i),

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

respectively.

Systems will determine compliance

based on the analytical result(s)

obtained at each sampling point. If any

sampling point is in violation of an

MCL, the system is in violation. For

systems monitoring more than once per

year, compliance with the MCL is

determined by a running annual average

at each sampling point. Systems

monitoring annually or less frequently

whose sample result exceeds the MCL

for any inorganic contaminant in

§ 141.23(c), or whose sample results

exceeds the trigger level for any organic

contaminant listed in § 141.24(f) or

§ 141.24(h), must revert to quarterly

sampling for that contaminant the next

quarter. Systems are only required to

conduct quarterly monitoring at the

entry point to the distribution system at

which the sample was collected and for

the specific contaminant that triggered

the system into the increased

monitoring frequency. Systems triggered

into increased monitoring will not be

considered in violation of the MCL until

they have completed one year of

quarterly sampling. If any sample result

will cause the running annual average to

exceed the MCL at any sampling point

(i.e., the analytical result is greater than

four times the MCL), the system is out

of compliance with the MCL

immediately. Systems may not monitor

more frequently than specified by the

State to determine compliance unless

they have applied to and obtained

approval from the State. If a system does

not collect all required samples when

compliance is based on a running

annual average of quarterly samples,

compliance will be based on the

running annual average of the samples

collected. If a sample result is less than

the method detection limit, zero will be

used to calculate the annual average.

States have the discretion to delete

results of obvious sampling or analytic

errors.

States still have the flexibility to

require confirmation samples for

positive or negative results. States may

require more than one confirmation

sample to determine the average

exposure over a 3-month period.

Confirmation samples must be averaged

with the original analytical result to

calculate an average over the 3-month

period. The 3-month average must be

used as one of the quarterly

concentrations for determining the

running annual average. The running

annual average must be used for

compliance determinations.

The rule requires that monitoring be

conducted at all entry points to the

distribution system. However, the State

has discretion to require monitoring and

determine compliance based on a caseby-case analysis of individual drinking

water systems. The Agency cannot

address all of the possible outcomes that

may occur at a particular water system;

therefore, EPA encourages drinking

water systems to inform State regulators

of their individual circumstances. Some

systems have implemented elaborate

plans including targeted, increased

monitoring that is more representative

of the average annual contaminant

concentration to which individuals are

being exposed (some States use a timeweighted or flow-weighted averaging

approach to determine compliance).

Some States require that systems

collect samples from wells that only

operate for one month out of the year

regardless of whether they are operating

during scheduled sampling times. The

State may determine compliance based

on several factors including, but not

limited to, the quantity of water

supplied by a source, the duration of

service of the source, and contaminant

concentration.

4. Monitoring and Compliance Schedule

Systems must begin complying with

the clarified monitoring and compliance

determination provisions of today’s rule

effective January 22, 2004 for inorganic,

volatile organic, and synthetic organic

contaminants. These requirements

clarify that for §§ 141.23(i)(2),

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

compliance will be determined based on

the running annual average of the initial

MCL exceedance and any subsequent

State-required confirmation samples. In

addition, the clarifications address

calculation of compliance when a

system fails to collect the required

number of samples. Compliance

(determined by the average

concentration) will be based on the total

number of samples collected. Some

systems have purposely not collected

the required number of quarterly

samples and only incurred monitoring

and reporting violations for the

uncollected samples. Any systems that

avoid required sampling will calculate

MCL violations by dividing the summed

samples by the actual number of

samples taken. This clarification did not

change §§ 141.23(i)(1) and

141.24(h)(11)(i) which allow systems to

use zero for all non-detects when

calculating MCL violations. In addition,

if any one sample would cause the

annual average to be exceeded, the

system is out of compliance

immediately.

Also in today’s rule, the Agency is

moving the arsenic monitoring and

compliance requirements from

§§ 141.23(l) to (q) to the standardized

monitoring framework in § 141.23 for

other IOCs. States may grant systems

nine-year monitoring waivers using the

conditions in § 141.23(c) for arsenic.

The criteria for developing a State

waiver program were published in the

Phase II/V rules, and as noted in section

IV.B. of this rule, the Agency is not

modifying the waiver criteria in today’s

rulemaking. However, the revised

arsenic rule is not effective until January

23, 2006 (see section I.M. for a more

detailed discussion regarding the

effective date of the rule.). States and

utilities supported moving arsenic into

the standardized monitoring framework.

To use compliance data after the

effective date of the 10 μg/L MCL,

systems must use an approved method

with a method detection limit

substantially less than the revised

arsenic MCL of 10 μg/L. This means that

after December 31, 2006 and December

31, 2007 all surface water systems and

groundwater systems, respectively, may

not use analytical methods using the

ICP–AES technology, because the

detection limits for these methods are 8

μg/L or higher. This restriction means

that two ICP–AES methods that were

approved when the MCL was 50 μg/L

may not be used for compliance

determinations at the revised MCL of 10

μg/L. The two methods are EPA Method

200.7 and SM 3120B. Prior to 2005,

systems may have compliance samples

analyzed with these less sensitive

methods. However, EPA advises

systems to have compliance samples

analyzed and reported at the laboratory

minimum detection limit.

If sampling demonstrates that arsenic

exceeds the MCL, a CWS will be

triggered into quarterly monitoring for

that sampling point ‘‘in the next quarter

after the violation occurred.’’ 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

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 6991

minimum of two consecutive ground

water, or four consecutive surface water

samples, have been collected

(§ 141.23(c)(8)).

The Agency is not promulgating a

reduced monitoring approach similar to

the revised radionuclides final rule

published on December 7, 2000 (65 FR

76708; EPA, 2000p). As noted above, all

systems have to collect IOC samples

once a year or once every three years,

depending on the source water, unless

they have a waiver. The Agency believes

that very few States issue waivers for

IOCs because the analysis is relatively

inexpensive and most IOCs are naturally

occurring elements that may be found in

concentrations above the method

detection limit. Therefore, the majority

of systems must collect routine samples

for the regulated IOCs; and most of the

methods used for analysis of these

contaminants will measure arsenic as

well as antimony, beryllium, cadmium,

chromium, copper, and nickel.

K. What do I Need to tell My Customers?

1. Consumer Confidence Reports

a. General requirements. In 1998, EPA

promulgated the Consumer Confidence

Report Rule (CCR) (codified at 40 CFR

part 141, subpart O), a final rule

requiring community water systems to

issue annual water quality reports to

their customers (63 FR 44512; EPA,

1998i). The reports are due each year by

July 1, and provide a snapshot of water

quality over the preceding calendar

year. The reports include information

on levels of detected contaminants and

if the system has violated an MCL or a

treatment technique, must also include

information on the potential health

effects of contaminants from appendix

A to subpart O. When they have such

violations, systems must also include in

their report an explanation of the

violation and remedial measures taken

to address it. The arsenic health effects

language is currently required when

arsenic levels exceed 25 μg/L, one-half

the existing MCL of 50 μg/L, required

under § 141.154(b).

EPA is today retaining the health

effects language for arsenic issued with

the final CCR Rule and updating

appendix A to subpart O to include the

MCL and MCLG as revised in this rule,

together with special arsenic-specific

reporting requirements.

In addition to the standard reporting

of arsenic detects and arsenic MCL

violations, EPA is today finalizing a

requirement (proposed at § 141.154(b);

finalized at § 141.154(f)) that CWSs that

detect arsenic between the revised and

existing MCL (i.e., above 10 μg/L and up

to and including 50 μg/L) prior to the

effective date for compliance with the

revised MCL, include the CCR Rule

health effects language in their reports.

This action is required even though,

technically, the systems are not in

violation of the regulations. This

requirement will be effective for the five

years after promulgation, when systems

are not yet required to comply with the

revised MCL. Then, beginning January

23, 2006, systems out of compliance

must report violations of the revised

arsenic MCL under § 141.153(d)(6) to

the public.

Based on stakeholder and commenter

input, the Agency decided in the final

CCR Rule that it would use authority

granted in SDWA section

1414(c)(4)(B)(vi) to require inclusion of

health effects language for arsenic

exceedances before the compliance date.

That section allows the Administrator to

require inclusion of health effects

language for ‘‘not more than three

regulated contaminants’’ other than

those found to violate an MCL. The

Agency used this authority for total

trihalomethanes in the Stage 1

Disinfectants and Disinfection

Byproducts Rule (63 FR 69390). The

Agency is now using this same authority

for arsenic, because it believes that it is

important to provide customers with the

most current understanding of the risk

presented by this contaminant as soon

as possible after establishing a new

standard. This provision provides

systems the flexibility to put this health

effects information into context and to

explain to customers that the system is

complying with existing standards.

EPA modified the language it

proposed on June 22, 2000 to reflect the

MCL promulgated today and to clarify

what language a system must include in

its report. Systems subject to

§ 141.154(f) must begin including the

arsenic health effects language in the

report due by July 1, 2002.

b. Special informational statement. In

addition, in the CCR Rule, the Agency

decided to require that CCRs include

additional information about certain

contaminants, one of which was arsenic.

As explained in the preamble to the

CCR Rule (63 FR 44512 at 44514; EPA,

1998i), because of commenters’

concerns about the adequacy of the

current MCL, EPA decided that systems

that detect arsenic between 25 μg/L and

the current MCL must include some

information regarding the arsenic

standard (§ 141.154(b)). This

informational statement is different

from the health effects language

required for an MCL violation. EPA

noted in the CCR rule and in the arsenic

proposal that the informational

statement requirement would be deleted

upon promulgation of a revised MCL.

In view of the fact that EPA is today

finalizing an MCL somewhat higher

than the technologically feasible MCL,

and that some commenters expressed

concern about the risk that a higherthan-feasible MCL might present to

certain consumers, EPA is today

retaining and revising an existing

§ 141.154(b) requirement that systems

which find arsenic below the MCL must

provide additional information to their

customers. EPA believes that consumers

should be aware of the uncertainties

surrounding the risks presented even by

very low levels of arsenic. While EPA

addressed many of the sources of

uncertainty in its risk analysis of arsenic

in support of the final rule, several

sources of uncertainty remain. Chief

among these is the mode of action (i.e.,

the shape of the dose-response curve).

EPA continues to research the effects of

arsenic (according to an arsenic research

plan required by the 1996 SDWA

Amendments and submitted to

Congress) and should have a better

understanding of these effects as the

relevant research is completed. EPA

believes that this uncertainty adequately

justifies retaining the existing

requirement to provide consumers with

information about low levels of arsenic.

The existing § 141.154(b) requirement

is today updated in two ways. First, the

arsenic level that triggers the additional

information is reset from 25 μg/L (half

the existing MCL) to 5 μg/L (half the

revised MCL). In the preamble to the

CCR Rule, we explained that ‘‘[many]

commenters agreed that half the MCL

would be an appropriate threshold for

requiring additional risk-related

information.’’ EPA continues to believe

that half the MCL is an appropriate

trigger for special information about

certain contaminants. Beginning with

the report due by July 1, 2002, CWSs

that find arsenic above 5 μg/L and up to

and including 10 μg/L must include

§ 141.154(b) special health information

about arsenic in their consumer

confidence reports.

Second, the suggested text of the

special information is updated. Rather

than stating that ‘‘EPA is reviewing the

drinking water standard for arsenic

. . .,’’ the statement announces clearly

that the consumer’s water meets EPA’s

new standard while also noting the costbenefit trade-off involved in setting that

standard. The suggested text further

notes that there are uncertainties

(described in section III.F of this notice)

surrounding the risks of low levels of

arsenic. Systems retain the flexibility, as

defined in the existing requirement, to

6992 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

adjust this language in consultation

with the Primacy Agency.

2. Public Notification

On May 4, 2000, EPA issued the final

Public Notification Rule (PNR) to revise

the minimum requirements that public

water systems must meet for public

notification of violations of EPA’s

drinking water standards (65 FR 25982;

EPA, 2000e). Water systems must begin

to comply with the revised 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 drinking water regulation

on arsenic affects public notification

requirements and amends the PNR as

part of its rulemaking.

Today’s final rule will require CWSs

and NTNCWSs 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. The new

arsenic MCL will become effective

January 23, 2006. CWSs and NTNCWSs

must provide public notification to

consumers for any violations after the

effective date of the revised arsenic

MCL. The PNR requires owners and

operators of public water systems to

give notice to persons they serve for all

violations when they are operating

under a variance or exemption (or

violate conditions of the variance or

exemption).

L. What Financial Assistance is

Available for Complying With This

Rule?

There are two major sources of

Federal financial assistance available for

water systems: the Drinking Water State

Revolving Fund (DWSRF) and the Water

and Waste Disposal Loan and Grant

Program of the Rural Utilities Service

(RUS) of the U. S. Department of

Agriculture.

The 1996 SDWA Amendments

authorized (i.e., approved spending)

$9.6 billion for the DWSRF program. To

date, Congress has appropriated (i.e.,

provided) $4.2 billion, which includes

$825 million for the program in Fiscal

Year 2001. By the end of September

2000, States had been awarded $3.2

billion in capitalization grants and, from

that, had provided more than $2.8

billion in assistance to eligible drinking

water systems. The Federal

capitalization grant, together with State

matching funds, is currently making

available about $1 billion per year.

States have considerable discretion in

designing their DWSRF program, and

have the option of offering special

assistance to systems that the State

considers to be disadvantaged. Special

assistance may include principal

forgiveness, a negative interest rate, an

interest rate lower than that charged to

non-disadvantaged systems, and

extended repayment periods of up to 30

years. Federal law allows DWSRF

assistance to be provided to water

systems of both public ownership and

private ownership, although some States

are unable or choose not to provide

assistance to privately owned systems.

EPA recognizes that public water

systems and States face a significant

challenge in implementing new

requirements that are needed to ensure

the continued provision of safe drinking

water. While the DWSRF program is

proving to be a significant source of

funding, it cannot be viewed as the only

source of funding. It will take a

concerted effort on the part of Federal,

State and local governments, private

business, and utilities to address the

significant infrastructure needs

identified by public water systems. In

order to ensure that the DWSRF

program is used to focus attention on

the highest priority needs, all States

must give priority to those drinking

water infrastructure improvement

projects that will have the greatest

public health benefit or ensure

compliance with SDWA. State DWSRF

programs are currently making loans

available to the highest ranked projects

on their lists and are also using a

portion of the grants to support other

important drinking water program

activities.

The RUS program is focused on

providing a safe, reliable water supply

and wastewater treatment to residents of

rural America. The program offers a

combination of low interest loans and

grants to systems serving rural areas and

cities and towns of up to 10,000 persons

and which are publicly owned

(including Native American systems) or

operated as not-for-profit corporations.

In recent years the RUS program has

typically offered assistance totaling

about $1.3 billion per year, about 60%

of which is directed to drinking water

projects. Thus, about $780 million per

year is available for rural drinking water

systems from this program. Together

with the approximately $1 billion per

year being made available through the

DWSRF, this results in a total of about

$1.78 billion per year of Federal

financial assistance available for

drinking water.

Other Federal financial assistance

programs exist that may help systems

with SDWA compliance related

expenditures. However, these other

programs are not generally as large or

focused on drinking water as are the

DWSRF and RUS programs. EPA’s

Environmental Financial Advisory

Board has developed a ‘‘Guidebook of

Financial Tools’’ (EPA, 1999c), which

offers a comprehensive summary of

public and private programs and

mechanisms for paying for drinking

water and other environmental systems.

The handbook is available through

EPA’s web site at: http://www.epa.gov/

efinpage/guidbk98/index.htm.

The Federal financial assistance

programs described previously clearly

face numerous, competing demands on

their resources. EPA’s 1995 Drinking

Water Infrastructure Needs Survey

(EPA, 1997a) identified a total 20-year

need for all systems of $138.4 billion.

The single largest category of need

(accounting for over half of the total

need) is installation and rehabilitation

of transmission and distribution

systems. Treatment needs constitute the

second largest category of need,

accounting for over 1⁄4 of total needs.

Storage and source rehabilitation and

development constitute the remaining

major categories of needs. Thus, systems

seeking financial assistance for

installation of arsenic treatment are

competing for resources with systems

seeking assistance for compliance with

other rules and with systems seeking

resources for basic infrastructure repair

and replacement. In seeking to meet

these numerous and competing needs,

the Agency recognizes the importance of

priority setting for financial assistance

programs. Systems having the financial

capability to secure funding through the

capital markets should do so, leaving

the Federal financial assistance

programs to assist the truly needy

systems. Since the demand for

assistance will likely outstrip the supply

of assistance, States may wish to

consider exemptions, which will

provide additional time for systems to

secure financial assistance.

M. What is the Effective Date and

Compliance Date for the Rule?

In the proposed rule, EPA made a

finding that all small systems (i.e.,

systems serving 10,000 people or less)

would be granted a 2-year capital

improvement extension which extends

the MCL effective date for purposes of

compliance with the new MCL to

January 23, 2006. EPA proposed the 2-

year capital improvement extension for

small systems because of the time

required for systems to plan, finance,

design and construct new treatment

systems.

Large systems were not provided this

additional time because of the greater

resources these systems have to perform

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 6993

capital improvements in a timely

manner. However, upon consideration

of information submitted by

commenters, EPA has determined that

large systems will also require an

additional 2 years to complete the

capital improvements necessary to

comply with the arsenic MCL. While

large systems (i.e., systems serving more

than 10,000 people) do have greater

resources to implement capital

improvements, (e.g., engineering and

construction management staff to

manage the projects), these systems

generally also have more entry points to

the distribution system that will require

treatment.

A number of treatment technologies

are listed as BAT for the proposed rule:

ion exchange, activated alumina, reverse

osmosis, modified coagulation/

filtration, modified lime softening and

electrodialysis reversal. There are also

several emerging technologies for

arsenic removal, such as nanofiltration

and granular ferric hydroxide. To ensure

cost effective compliance with the

arsenic MCL, systems will need to

evaluate their treatment technology

options as a first step. This planning

step may include pilot studies with

potential treatment systems, or it may be

limited to an evaluation of the raw

water characteristics. Systems choosing

to conduct pilot testing may take a year

or more to contract with vendors and to

perform pilot testing.

Once the planning step is completed

systems must design and construct the

treatment systems. Design and

permitting of the treatment systems can

take an additional year, and

construction of the treatment system can

take another year. Because systems will

also need time to: obtain funding, obtain

local government approval of the

project, or acquire the land necessary to

construct these technologies, it is likely

that most large systems will need

additional time beyond the three-year

effective date for compliance with the

new MCL that EPA proposed.

Based upon these considerations, EPA

determined, in accordance with section

1412(b)(10) of SDWA, that the

compliance date for the new arsenic

MCL, regardless of system size, will be

5 years from the date of promulgation of

the standard. See section I.H. for more

information regarding variance and

exemptions.

N. How Were Stakeholders Involved in

the Development of This Rule?

EPA met extensively with a broad

range of groups during the development

of the arsenic proposal, both at EPAsponsored meetings and at other

organizations’ meetings. The Federal

Register published notices about EPA’s

arsenic meetings, and we made

conference call lines available for those

who chose not to attend in person. In

addition, EPA notified people about

regulatory actions via the three Federal

Register notices (proposal, notice of

data availability, and correction notice),

by mail and e-mail. Over 600 people

asked to be on the mailing list during

the regulatory development period.

EPA held arsenic stakeholders

meetings September 11–12, 1997 in

Washington, DC; February 25, 1998 in

San Antonio, Texas; May 5, 1998 in

Monterey, California; June 2–3, 1999 in

Washington, DC; and August 9, 2000 in

Reno, Nevada. For each of these

meetings we invited representatives of

States, tribal groups, associations,

utilities and environmental groups. The

docket for the proposed rule (W–99–16)

contains the meeting discussion papers,

agendas, participants lists, presentation

materials, and executive meeting

summaries. All the meeting materials,

except the presentations and attendance

list, are also available on EPA’s arsenic

in drinking water web page,

www.epa.gov/safewater/arsenic.html.

EPA also presented sessions on

drinking water regulations (including

arsenic) at the National Indian Health

Board Annual Conference in Anchorage,

Alaska in September 1998. The Intertribal Council of Arizona hosted a

consultation for EPA with Tribes

February 24–25, 1999 in Las Vegas, NV

at which an overview of the proposed

arsenic regulation was presented. EPA

also conducted a series of workshops at

the Annual Conference of the National

Tribal Environmental Council May 18–

20, 1999 in Eureka, California. The

Council distributed materials and

gathered comments on EPA’s drinking

water regulations from all recognized

Tribal governments.

In addition to the general stakeholder

meetings, EPA also had targeted

meetings with States’ representatives. In

May 1999, State regulatory

representatives from California, Nevada,

Michigan, Illinois, Texas, Indiana, New

Mexico, and Louisiana joined EPA in a

discussion on the development of the

cost of compliance decision tree. In

August 1999, State regulatory

representatives from Illinois, Indiana,

New Mexico, and Texas joined EPA

workgroup members in a discussion of

the NRC study use, review of the

occurrence work, treatment technology

update, and regulatory changes. The

interaction from these meetings with

State colleagues improved the

regulatory language and the preamble.

In May 2000, EPA presented a

summary of the rule to the National

Governors’ Association. In May 2000,

EPA held a dialogue in Washington, DC

with State officials and the associations

that represent elected officials.

Presentations on arsenic and other

drinking water rules under development

were given to representatives of the

National Association of Towns and

Townships, National Governors’

Association, National Association of

Counties, National League of Cities,

Association of State Drinking Water

Administrators, Environmental Council

of the States, Florida Department of

Environmental Protection, Drinking

Water Section, Association of State and

Territorial Health Officials, and the

International City/County Management.

The purpose of the dialogue was to

consult on the expected compliance and

implementation costs of these rules for

State, county, and local governments

and gain a better understanding of the

views of representatives of State,

county, and local governments and their

elected officials. The meeting materials

are in the docket for the proposed rule.

In addition to the various special

meetings and discussions mentioned

previously, EPA representatives

delivered arsenic regulatory

development presentations at a variety

of meetings held by other organizations.

These included the American Water

Works Association (AWWA) Inorganic

Contaminants Meetings in February,

1998 in San Antonio, TX and in

February, 2000 in Albuquerque, NM;

meetings of the Association of State

Drinking Water Administrators

(ASDWA) in February and October

1998, March and October 1999, and in

October 2000; meetings of the

Association of Metropolitan Water

Agencies (AMWA) in January and

March 1998; and a meeting of the

Association of California Water

Agencies in March 1998. EPA also gave

several technical presentations and

regulatory updates at the AWWA annual

meetings as well as at the AWWA Water

Quality and Technology Conferences in

1998, 1999, and 2000. EPA participated

in the Society of Toxicology arsenic

workshop in Philadelphia, PA in March

2000. Finally, EPA co-sponsored and

participated in the four International

Conferences on Arsenic Exposure and

Health Effects in July 1993, June 1995,

July 1998, and June 2000.

After the proposal was published in

the Federal Register, EPA notified all

persons on its electronic mailing list for

the arsenic rule of its availability and

sent information. The Regulatory Impact

Analysis went on the arsenic web page

a week after the proposal publication.

Similarly, EPA also notified the

individuals and organizations on this

6994 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

mailing list about the NODA and the

correction notice.

II. Statutory Authority

Section 1401 of SDWA requires a

‘‘primary drinking water regulation’’ to

specify a MCL if it is economically and

technically feasible to measure the

contaminant and to include testing

procedures to insure compliance with

the MCL and proper operation and

maintenance. An 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 must also list affordable

technologies that achieve compliance

with the MCL or treatment technique for

three categories of small systems: those

serving 10,000 to 3301 persons, 3300 to

501 persons, and 500 to 25 persons. EPA

can list modular (packaged) and POE

and POU 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 NAS, other

Federal agencies, and interested public

and private entities. The amendments

allowed EPA to enter into cooperative

agreements for research. On October 27,

2000, Public Law 106–377, the bill

which included Fiscal Year 2001

appropriations for EPA, amended the

statutory deadline to direct EPA to

promulgate a final arsenic standard by

no later than June 22, 2001.

Section 1412(a)(3) requires EPA to

propose an MCLG simultaneously with

the NPDWR. The MCLG is defined in

section 1412(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 NPDWR will specify an 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 (section

1412(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

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. As

required by the statute, EPA issued a

HRRCA for arsenic (EPA, 2000i) as

section XIII of the June 22, 2000 arsenic

proposal (65 FR 38888 at 38957).

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 this

obligation, EPA must specify, among

other things,

peer-reviewed studies known to the

Administrator that support, are directly

relevant to, or fail to support any estimate of

public health effects and the methodology

used to reconcile inconsistencies in the

scientific data (section1412(b)(3)(B)(v)).

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

States primary enforcement

responsibility (primacy) 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

granted. 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 an

NPDWR has primacy enforcement

authority for the new regulation while

EPA action on the revision is pending

(section 1413(c)). Section 1451(a) allows

EPA to grant primacy enforcement

responsibility to Federally recognized

Indian Tribes, providing grant and

contract assistance, using the

procedures applied to States.

III. Rationales for Regulatory Decisions

A. What Is the MCLG?

The proposed rule suggested that an

MCLG of zero be established for arsenic

in view of the fact that we are currently

unable to specify a safe threshold level

due to uncertainty about the mode of

action for arsenic. Today’s rule

establishes a final MCLG for arsenic of

zero. After full consideration of public

comments, EPA continues to believe

that the most scientifically valid

approach, given the lack of critical data,

is to use the linear approach to assessing

the mode of action. This approach

results in an MCLG of zero. In the

proposal and the NODA, EPA noted that

the available data point to several

potential carcinogenic modes of action

for arsenic (EPA also requested

additional data on the mode of action).

However, which mode(s) of action is

operative is unknown. For this reason,

while the Agency recognizes that the

dose-response relationship may be

sublinear, the data do not provide any

basis upon which EPA could reasonably

construct this relationship. Thus, EPA

has no basis upon which to depart from

its assumption of linearity. The NRC

report noted that available data that

could help determine the shape of the

dose-response curve are inconclusive

and do not meet EPA’s stated criteria for

departure from the default assumption

of linearity (NRC, 1999). See section

III.D.1 for a thorough discussion of the

dose-response assessment.

Because the postulated mode of action

for arsenic cannot specifically be

described and the key events are

unknown, the Agency lacks sufficient

available, peer-reviewed information to

estimate quantitatively a non-linear

mode of action. The Agency has thus

decided not to depart from the

assumption of linearity in selecting an

MCLG of zero.

B. What Is the Feasible Level?

1. Analytical Measurement Feasibility

In the development of a drinking

water regulation, EPA derives a

practical quantitation limit (PQL) to

estimate or evaluate the minimum,

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 6995

reliable quantitation level

(concentration) that most laboratories

can be expected to meet during day-today operations. The PQL accounts for

the limits of current measurement

technologies and the laboratories that

use the methods written around these

analytical technologies. The PQL was

defined in a November 13, 1985 rule (50

FR 46906, EPA, 1985b) as ‘‘the lowest

concentration of an analyte that can be

reliably measured within specified

limits of precision and accuracy during

routine laboratory operating

conditions.’’ A PQL is determined either

through use of interlaboratory studies

or, in absence of sufficient studies,

through the use of a multiplier of 5 to

10 times the method detection limit

(MDL). Interlaboratory data are obtained

from water supply (WS) studies that are

conducted by EPA to certify drinking

water laboratories. The WS studies

require a candidate laboratory to

measure the concentration of the target

analyte within specified limits (e.g.,

±30%) of the amount spiked into a PE

(now called PT) challenge sample.

Using graphical or linear regression

analysis of the WS data, the Agency sets

a PQL at a concentration where at least

75% of experienced laboratories

(generally EPA and State laboratories)

could perform within this acceptable

limit for accuracy, e.g., ±30%.

As discussed in the June 22, 2000

proposed rule for arsenic, the Agency

determined that the PQL (i.e., the

feasible level of measurement) for

arsenic in drinking water is 0.003 mg/

L with an acceptance limit of ±30%. The

derivation of the PQL for arsenic is

consistent with the process used to

determine PQLs for other metal

contaminants regulated under SDWA

and takes into consideration the

recommendations from EPA’s SAB

(EPA, 1995). Using acceptance limits of

±30% and linear regression analysis of

six recent WS studies, EPA derived a

PQL of 0.00258 mg/L for arsenic, which

was rounded to 0.003 mg/L at the ±30%.

While the PQL represents a relatively

stringent target for laboratory

performance, based on the WS data used

to derive the PQL for arsenic, the

Agency believes most laboratories

(using appropriate quality assurance

and quality control procedures) can

achieve this level on a routine basis.

2. Treatment Feasibility

EPA has determined that 3 μg/L is

technologically feasible for large

systems based on peer-reviewed

treatment information. EPA has listed

seven BATs for arsenic in the final rule.

They are: ion exchange when sulfate

≤50 mg/L, activated alumina, reverse

osmosis, modified coagulation/

filtration, modified lime softening at pH

>10.5, electrodialysis reversal, and

oxidation/filtration when the iron to

arsenic ratio is at least 20:1. Bench, pilot

and full-scale data were examined to

determine the capabilities of the

treatment processes. The treatment

performance data are summarized in

‘‘Technologies and Costs for the

Removal of Arsenic from Drinking

Water’’ (EPA, 2000t).

C. How Did EPA Revise its National

Occurrence Estimates?

1. Summary of Occurrence Data and

Methodology

Our data and methodology for

estimating arsenic occurrence are

substantially the same as in the

proposed rule (65 FR 38888 at 38903;

EPA, 2000i). The data and methodology

are described in detail in (EPA, 2000r).

Following is a summary of our method.

All of the elements of this summary are

the same as in the proposed rule, except

where noted.

Our occurrence database consists of

arsenic compliance monitoring samples

of finished drinking water, submitted

voluntarily by drinking water agencies

in 25 States. The 25 States are

distributed throughout the U.S., with at

least one located in each of the seven

geographic regions that we used in our

analysis (65 FR 38888 at 38906; EPA,

2000i; EPA, 2000r). In some States we

used data only from a subset of years in

which detection limits were lowest. For

each PWS in our database, we estimated

the mean arsenic concentration over

time in finished water, by first ‘‘filling

in’’ non-detected concentrations, using

one of two statistical methods (EPA,

2000r), then averaging the detected and

filled-in observations from that system.

Next, we collected the system mean

estimates into State distributions, then

merged the State distributions into

regional and then national distributions.

In combining the regional distributions

into a national distribution, we

weighted each region by the total

number of systems in the region, not

just the number of systems in the States

in our database. This procedure has the

same effect as assigning the regional

distributions to the 25 States for which

we have no observations in our

database.

In addition to the distributions of

system means, we estimated nationwide

intra-system coefficients of variation

(ISCV). For a given water system, the

ISCV quantifies the variation of mean

arsenic levels at the system’s entry

points to the distribution system (i.e.,

sampling points of individual wells and

treatment points) around the overall

system mean. We estimated a separate

ISCV for each ground water (gw) CWS,

surface water (sw) CWS, and, unlike in

the proposed rule, ground water

NTNCWS. Each of these ISCVs is

assumed to be constant throughout the

U.S.

2. Corrections and Additions to the Data

Some public commenters asked

whether our data might have errors in

the classification of water samples as

treated or untreated. If that were the

case, then including untreated samples

in our database could cause us to

overestimate occurrence in finished

water. In order to determine whether

and to what extent these problems exist,

we solicited additional data sets from

drinking water agencies in six States

(Alabama, California, Illinois, New

Mexico, North Carolina, and Texas)

from whom we already had data in our

draft data set. All six States responded

to our request by submitting additional

data, including additional identifiers of

untreated observations, as well as some

new observations not contained in our

draft data base. In California, once the

newly identified untreated observations

were removed from the data set, the

number of surface water observations

decreased from 2,488 in the draft data

set to 1,280 in the final data set. For

ground water, on the other hand, the

number of samples in California

increased from 5,622 to 9,494. The

increase resulted in part from the

additional data, and in part because we

changed our methodology, as we

describe below, to include samples from

both treated and untreated ground water

in our ground water estimates. Changes

in the other five States were of smaller

size.

We also updated our data set from

Utah. The latest data from Utah include

more observations and covers the years

1980 to 1999. The total number of

observations from Utah in our data set

increased from 2,447 to 4,684.

Table III.C–1 compares the number of

observations, systems, and States in our

database, by system type and source

water type, in the proposed and final

rules. Note that our complete database

is larger than shown in Table III.C–1,

but in some States we excluded data

from some years in which analytical

detection limits were highest. Table

III.C–1 counts only the data from the

years that we used to estimate

occurrence.

6996 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

TABLE III.C–1.—SUMMARY OF OCCURRENCE DATABASES FOR THE PROPOSED AND FINAL RULES

System type Source water

Proposed rule Final rule

# of

observations

# of

systems

# of

States

# of

observations

# of

systems

# of

States

CWS ...................................... GW ........................................ 44,502 15,640 25 53,307 15,931 25

CWS ...................................... SW ........................................ 15,892 2,360 25 16,212 2,228 25

NTNCWS .............................. GW ........................................ * 6,420 * 4,662 * 18 7,045 4,382 17

NTNCWS .............................. SW ........................................ * 420 * 150 * 14 * 409 * 118 * 15

All .......................................... All .......................................... 67,234 22,812 25 76,973 22,659 25

* Data not used in estimating occurrence.

We also updated our baseline

inventory of the public water systems in

the U.S. and the populations they serve,

by type of system, type of source water,

and State. We use this inventory to

estimate the numbers of systems and

people affected by different MCL

options, by multiplying the number of

people or systems in a given category by

the estimated fraction of systems in that

category with mean arsenic greater than

the levels of interest. In the proposed

rule, the occurrence and regulatory

impact analyses used different sets of

baseline estimates: occurrence took

baseline estimates from EPA’s 4th

quarter 1997 Safe Drinking Water

Information System (SDWIS) database,

while the proposal’s regulatory impact

analysis (RIA) used 4th quarter 1998

SDWIS. The result, as some public

commenters pointed out, was that the

proposed rule contained two

inconsistent sets of estimates of the

numbers of people and systems affected

by different MCL options (65 FR 38888;

EPA, 2000i, Table V–3; EPA, 2000h,

Exhibit 4–11). The two estimates of total

numbers of systems affected at various

MCLs differed by up to 27%. We

corrected this inconsistency by

adopting, with one modification, the

baseline inventory in EPA’s Drinking

Water Baseline Handbook (EPA, 2000b)

throughout this preamble and all

supporting documents for the final rule.

The inventory in the Baseline Handbook

is taken from EPA’s 4th quarter 1998

SDWIS database, or the same that was

used in the proposed RIA. The only

modification we made to the inventory

was in Alaska where the Baseline

Handbook lists zero NTNCWS and zero

population served by NTNCWS.

Following public comment from the

Alaska Department of Environmental

Conservation, we corrected the

inventory of NTNCWS in Alaska. The

Baseline Handbook and corrected

Alaska inventories are shown in Table

III.C–2.

TABLE III.C–2.—ALASKA PWS INVENTORIES: BASELINE HANDBOOK AND CORRECTED

System type Source water

Baseline handbook Corrected

No. of systems Population

served No. of systems Populationserved

CWS .................................................. GW ................................................... 508 227,874 344 175,367

CWS .................................................. SW .................................................... 160 317,155 121 260,792

NTNCWS .......................................... GW ................................................... 0 0 161 51,909

NTNCWS .......................................... SW .................................................... 0 0 35 56,013

All ...................................................... All ...................................................... 668 545,029 661 544,081

The revised estimates of numbers of

systems affected at different arsenic

concentrations are shown in Table III.C–

6. Since the proposed and final

Economic Analysis use the same set of

baseline estimates (except for the small

correction in Alaska), changes in Table

III.C–6 compared to the proposed RIA

(EPA, 2000h, Exhibit 4–11) are due to

changes in the occurrence estimates in

Table III.C–3, which follows. Changes in

Table III.C–6 compared to the proposed

occurrence analysis (65 FR 38888; EPA,

2000i, Table V–3) are due to changes in

occurrence estimates and also correction

of the baseline.

3. Changes to the Methodology

In September 1999, EPA sponsored a

peer review of our occurrence data and

methodology by three independent

experts in geochemistry and statistics.

In response to that review and public

comments, we have made minor

revisions to our methodology for

estimating occurrence in two ways since

the proposed rule.

First, we now estimate the occurrence

distribution for ground water NTNCWSs

separately from CWSs. In the proposed

rule, we used the CWSs distribution as

a surrogate for NTNCWSs, for both

ground and surface water systems. We

now estimate occurrence in ground

water NTNCWSs separately, using the

same method as for CWSs, as described

previously. For ground water NTNCWSs

we have data from 17 States, compared

to 25 States for CWSs, so there are on

average fewer States with data in each

region. Moreover we have no data about

NTNCWSs from any States in the

Southeast region (Alabama, Florida,

Georgia, Mississippi, and Tennessee).

We therefore used the occurrence

distribution for ground water CWSs as

a surrogate for ground water NTNCWSs

in the Southeast. The revised

occurrence estimates for ground water

NTNCWSs are shown in Table III.C–3.

We still do not estimate a separate

occurrence distribution for surface

water NTNCWSs. For surface water

NTNCWSs, we did not believe that the

118 systems for which data were

provided for NTNCWSs formed as

strong a basis for estimating occurrence

as the much larger CWS surface water

data base, especially in the

concentration range of interest. In

addition, there is less reason to believe

that surface water NTNCWSs will differ

from surface water CWSs. We thus

believe the surface water CWS estimates

provide the soundest basis for

estimating impacts given the types of

data available.

Second, we have improved our

method for estimating intra-system

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 6997

variability. In the proposed rule, we

estimated the ISCV by measuring the

total amount of variability of arsenic

concentrations around the system mean

within each system. The problem with

that approach is that it fails to

distinguish between-source variability

(variability of sampling-point means

around the system mean) from withinsource variability (variability of

observations at each sampling point

around the sampling-point mean).

Within-source variability includes

variations in concentrations through

time at a source, and analytical

variability caused by imprecision of the

analytical methods used to measure

arsenic in water samples. The ISCV is

intended to describe only betweensource variability within a system.

Following the recommendations of the

peer review, we corrected our model of

intra-system variation to include

separate terms for between-source and

within-source variability. As a result,

our estimates of the ISCVs decreased,

since we separate out the within-source

variability. The revised ISCV estimates

are shown in Table III.C–7.

A third change to our methodology is

that, for ground water systems, we now

include observations on both treated

and untreated ground water in our

analysis. With the exception of iron

removal technologies, most treatment in

ground water systems has little effect on

arsenic, so one might expect arsenic

concentrations to be similar in treated

and untreated samples. This turns out to

be the case in our data: estimates that

included untreated samples were either

slightly higher or lower than estimates

with only treated samples. We therefore

decided to include both treated and

untreated samples in our ground water

occurrence estimates. For surface water

estimates, we still use only samples

from treated water.

4. Revised Occurrence Results

Table III.C–3 shows our revised

estimates of the national distribution of

arsenic occurrence, by system type and

source water type. The distributions are

stated in terms of ‘‘exceedance

probabilities,’’ that is, the fraction of

systems with mean arsenic equal to or

greater than the given concentration, in

finished water. The ‘‘weighted point

estimate’’ is the combination of State

distributions into a national

distribution, as described previously.

We consider the weighted point

estimate to be our best estimate. The

‘‘lognormal fit’’ is the result of fitting a

lognormal distribution to the weighted

point estimates. The lognormal fit is an

approximation to the weighted point

estimate, which we use in our cost and

benefit analyses (sections III.E and III.F).

The lognormal approximation simplifies

the simulation studies that we use to

derive costs and benefits, by allowing

each distribution to be summarized in

terms of only two parameters. Table

III.C–4 lists the parameters of the fitted

lognormal distributions.

TABLE III.C–3.—NATIONAL OCCURRENCE EXCEEDANCE PROBABILITY ESTIMATES

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

3 5 10 20 50

Ground Water CWS

Weighted point estimate ...................................................... 19.9 12.1 5.3 2.0 0.43

95% confidence interval 1 .................................................... [19.3,21.9] [11.7,13.0] [5.2,5.9] [1.9,2.3] [0.38,0.52]

Lognormal fit ........................................................................ 19.7 12.0 5.3 2.0 0.43

Surface Water CWS

Weighted point estimate ...................................................... 5.6 3.0 0.80 0.32 0.10

95% confidence interval 1 .................................................... [4.8,20.6] [1.8,9.7] [0.52,1.6] [0.13,0.82] [0.02,0.59]

Lognormal fit ........................................................................ 5.6 3.0 1.1 0.37 0.067

Ground Water NTNCWS

Weighted point estimate ...................................................... 24.2 15.6 5.3 2.1 0.47

95% confidence interval 1 ....................................................

Lognormal fit ........................................................................ 23.4 14.2 6.1 2.2 0.42

1Brackets indicate confidence intervals which were computed for the proposed rule and have not been updated. No confidence intervals were

computed for NTNCWS.

TABLE III.C–4.—PARAMETERS OF LOGNORMAL DISTRIBUTIONS FITTED TO NATIONAL OCCURRENCE DISTRIBUTIONS

System type Source water Log-mean 1 Log-SD 2

CWS ............................................................................. GW ................................................................................ ¥0.25 1.58

CWS ............................................................................. SW ................................................................................ ¥1.68 1.74

NTNCWS ...................................................................... GW ................................................................................ 0.03 1.47

1 Log-mean = mean of natural logarithm of arsenic concentrations (μg/L). 2 Log-SD = standard deviation of natural logarithm of arsenic concentrations (μg/L).

Table III.C–3 lists separate

distribution estimates for ground and

surface water CWS and for ground water

NTNCWSs. As we said previously, we

believe surface water CWSs provide a

more sound basis for estimation.

For CWSs, the estimates in Table

III.C–3 have changed only slightly since

the proposed rule. For ground water

CWSs, the largest change is an increase

at 10 μg/L from 5.3% exceedance to

5.4%. For surface water CWSs, the

largest change is a decrease at 3 μg/L

from 6.0% in the proposed rule to 5.6%

in Table III.C–3. This decrease is as

expected, since, as we explained

previously, our revised database

excludes some observations on

untreated water that were included in

the draft database. Our surface water

6998 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

occurrence estimates did increase

slightly at 5 μg/L, however, as Table

III.C–8 shows.

For ground water NTNCWSs, our

estimated exceedance probabilities

increased from 19.9% to 24.2% at 3 μg/

L, and from 12.1% to 15.6% at 5 μg/L.

The estimates at higher concentrations

changed by at most 0.1% point. The

estimates changed because we now

estimate a separate distribution for

ground water NTNCWSs, as we

described previously.

The confidence intervals listed in

Table III.C–3 were computed for the

proposed rule, using a computationally

intensive resampling procedure, as

described in (EPA, 2000r). Since our

data set and point estimates have

changed only minimally for the final

rule, we did not recompute the

confidence intervals.

Table III.C–5 shows occurrence

distributions in seven geographic

regions presented in the proposal and

developed by Frey and Edwards (1997).

(The States and names of these

geographic regions in Table III.C–5 are

based directly on the authors’

designations.) As in the proposed rule,

we find concentrations to be generally

highest in the West, and generally

lowest in the Southeast and MidAtlantic. In regions where analytical

reporting limits in our database were

mostly higher than 3 μg/L or 5 μg/L, we

did not attempt to estimate occurrence

at the lowest concentrations. These

cases are indicated by dashes in Table

III.C–5. In some regions, we were able

to estimate occurrence in fewer States at

the lowest concentrations, and this

sometimes led to inconsistencies in our

estimates. For example, for New

England surface water CWSs, we

estimated occurrence at 3 μg/L using

only Maine, and at 5 μg/L using Maine,

New Hampshire, and New Jersey. The

introduction of more States at higher

concentrations led to inconsistent

estimates of 6.2% and 11.7% of New

England surface water CWSs with

arsenic exceeding 3 μg/L and 5 μg/L,

respectively. We did not try to resolve

these inconsistencies at the regional

level, but note that the national

occurrence distributions, listed in Table

III.C–3, are consistent.

TABLE III.C–5.—REGIONAL OCCURRENCE EXCEEDANCE PROBABILITY ESTIMATES

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

3 5 10 20

Ground Water CWS

Mid-Atlantic ...................................................................................................... (2) *0.4 0.7 0.0

Midwest ............................................................................................................ 21.2 13.8 6.2 2.4

New England ................................................................................................... 21.7 20.8 7.0 2.9

North Central ................................................................................................... 21.3 13.1 6.0 2.4

South Central ................................................................................................... 18.6 9.7 3.6 1.1

Southeast ......................................................................................................... 0.9 0.4 0.1 0.0

West ................................................................................................................. 31.5 25.2 12.5 5.0

Surface Water CWS

Mid-Atlantic ...................................................................................................... (2) 0.1 0.0 0.0

Midwest ............................................................................................................ 3.0 1.6 0.7 0.3

New England ................................................................................................... 1 6.2 11.7 1.0 0.4

North Central ................................................................................................... 9.1 3.2 0.6 0.1

South Central ................................................................................................... 3.8 0.9 0.2 0.1

Southeast ......................................................................................................... 0.2 0.1 0.0 0.0

West ................................................................................................................. 12.7 8.2 3.4 1.4

Ground Water NTNCWS

Mid-Atlantic ...................................................................................................... (2) (2) 1.4 0.5

Midwest ............................................................................................................ 26.2 17.1 8.2 3.3

New England ................................................................................................... (2) (2) 2.1 0.6

North Central ................................................................................................... 29.8 22.8 15.0 9.3

South Central ................................................................................................... 24.0 14.4 5.9 1.9

Southeast ......................................................................................................... 0.9 0.4 0.1 0.0

West ................................................................................................................. 34.3 21.9 10.5 4.2

1Estimate is inconsistent with estimate at the next higher concentration. See text for explanation.

2 Means not enough data to form an estimate. See text for explanation.

Table III.C–6 shows our estimates of

the numbers of systems with mean

finished arsenic concentrations in

various ranges, by system type and size.

As in the proposed rule, we find no

evidence of any consistent difference in

mean arsenic among systems of different

sizes. We conclude that the occurrence

distributions shown in Table III.C–3

apply to all categories of system size. In

Table III.C–6, therefore, the estimated

numbers of systems are computed by

multiplying the baseline inventory of all

systems of the given size and type, by

the corresponding probability of falling

within the given range, computed from

Table III.C–3 and shown in the ‘‘% of

systems’’ rows. The estimates for surface

water NTNCWSs were computed by

applying the occurrence distribution for

surface water CWSs to the baseline

inventory of surface water NTNCWSs.

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 6999

TABLE III.C–6.—STATISTICAL ESTIMATES OF NUMBERS OF SYSTEMS WITH AVERAGE FINISHED ARSENIC CONCENTRATIONS

IN VARIOUS RANGES

System size (population served)

Number of systems with mean arsenic concentration (μg/L) in the

range of:

>3 to 5 >5 to 10 >10 to 20 >20

Ground Water CWS

25 to 500 .......................................................................................................... 2,272 1,980 961 584

501 to 3,300 ..................................................................................................... 811 706 343 208

3,301 to 10,000 ................................................................................................ 192 167 81 49

10,001 to 50,000 .............................................................................................. 95 83 40 24

>50,000 ............................................................................................................ 15 13 6 4

All ..................................................................................................................... 3,384 2,949 1,432 870

% of systems ................................................................................................... 7.8% 6.8% 3.3% 2.0%

Surface Water CWS

25 to 500 .......................................................................................................... 76 68 14 10

501 to 3,300 ..................................................................................................... 92 81 17 12

3,301 to 10,000 ................................................................................................ 47 41 9 6

10,001 to 50,000 .............................................................................................. 41 36 8 5

>50,000 ............................................................................................................ 15 13 3 2

All ..................................................................................................................... 270 239 51 34

% of systems ................................................................................................... 2.5% 2.2% 0.5% 0.3%

Ground Water NTNCWS

25 to 500 .......................................................................................................... 1,440 1,713 545 348

501 to 3,300 ..................................................................................................... 230 274 87 56

3,301 to 10,000 ................................................................................................ 5 6 2 1

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

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

All ..................................................................................................................... 1,677 1,995 635 405

% of systems ................................................................................................... 8.6% 10.3% 3.3% 2.1%

Surface Water NTNCWS

25 to 500 .......................................................................................................... 14 13 3 2

501 to 3,300 ..................................................................................................... 5 4 1 1

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

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

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

All ..................................................................................................................... 20 17 4 2

% of systems ................................................................................................... 2.5% 2.2% 0.5% 0.3%

Numbers do not add up to totals in some cases due to rounding.

Our proposed and final estimates of

intra-system coefficients of variation are

shown in Table III.C–7. The revised

estimates are lower, since, as we

described previously, we now better

separate out within-source (time and

analytical) variability from the

variability of source means within a

system. The ISCV estimate for ground

water NTNCWSs also has changed

because we now estimate it separately

from that of ground water CWSs.

TABLE III.C–7.—ESTIMATED INTRA-SYSTEM COEFFICIENTS OF VARIATION (ISCV)

System type Source water

Proposed rule Final rule

ISCV (percent) ISCV (percent) 95% confidence

interval

CWS ...................................................... GW ......................................................... 62.9 37.1 [33.1,40.8]

CWS ...................................................... SW ......................................................... 68.4 52.6 [31.4,69.6]

NTNCWS ............................................... GW ......................................................... 62.9 25.2 [9.6,34.7]

Table III.C–8 compares our proposed

and final national occurrence estimates

to estimates from three other studies:

the National Arsenic Occurrence Survey

(NAOS) (Frey and Edwards, 1997),

National Inorganics and Radionuclides

Survey (NIRS) (Wade Miller Associates,

1992), and U.S. Geological Survey

(USGS) (USGS, 2000). All of the studies

in Table III.C–8 evaluated drinking

water except for USGS, which evaluated

ambient ground water, some of which

came from non-drinking water sources.

Wade Miller used surface water

estimates from the 1978 Community

Water System Survey, which we

consider now to be out of date, so those

estimates are not shown. Note that Frey

and Edwards (1997) found significantly

different occurrence distributions for

small and large systems, so the NAOS

7000 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

estimates are reported separately for

small and large systems. The NAOS

included samples from all 50 States, but

it was a much smaller study (468

samples, compared to about 77,000 in

our database), and it analyzed

unfinished water samples. Frey and

Edwards (1997) applied estimated

efficiencies for the treatments known to

be in place at the sampling locations, to

predict the concentrations in finished

water.

TABLE III.C–8.—COMPARISON OF NATIONAL ARSENIC OCCURRENCE ESTIMATES

Study Type of water System types Population served

% of systems with mean arsenic exceeding concentrations (μg/L) of:

2 3 5 10 20

Ground Water Systems

EPA-proposed .............. raw + finished .............. CWS ............................ all ................................. 27.2 19.9 12.1 5.4 2.1

EPA-final ...................... raw + finished .............. CWS ............................ all ................................. 27.3 19.9 12.1 5.3 2.0

NAOS-small ................. finished 1 ...................... PWS ............................ ≤ 10,000 ....................... 23.5 NR 12.7 5.1 NR

NAOS-large .................. finished 1 ...................... PWS ............................ > 10,000 ....................... 28.8 NR 15.4 6.7 NR

NIRS ............................. finished ........................ CWS ............................ all ................................. 17.4 11.9 6.9 2.9 1.1

USGS ........................... raw ............................... PWS ............................ all ................................. 25.0 NR 13.6 7.6 3.1

Surface Water Systems

EPA-proposed .............. finished ........................ CWS ............................ all ................................. 9.9 6.0 2.9 0.8 0.3

EPA-final ...................... finished ........................ CWS ............................ all ................................. 9.8 5.6 3.0 0.8 0.3

NAOS-small ................. finished 1 ...................... PWS ............................ ≤ 10,000 ....................... 6.2 NR 1.8 0.0 NR

NAOS-large .................. finished 1 ...................... PWS ............................ > 10,000 ....................... 7.5 NR 1.3 0.6 NR

NR = not reported.

1Predicted from raw water, using estimated efficiency of treatment in place.

Table III.C–8 shows that our proposed

and final occurrence estimates are only

slightly different, with the possible

exception of surface water occurrence

estimates at 3 μg/L, where our estimate

decreased from 6.0% to 5.6%

exceedance for the final rule. The

difference is explained by the

identification and exclusion of samples

of untreated water from our database for

the final rule, as we described

previously. For ground water, our

estimates fall within the range reported

in the other three studies. For surface

water, our estimates are somewhat

higher than those of the NAOS.

D. How Did EPA Revise its Risk

Analysis?

1. Health Risk Analysis

a. Toxic forms of arsenic. Humans are

exposed to many forms of arsenic that

have different toxicities. 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). Little is known about the

various arsenic species in vegetables,

grains, and oils (NRC, 1999). Arsenite

(+3) and arsenate (+5) are the most

prevalent toxic forms of inorganic

arsenic found in drinking water. In

general, the inorganic forms of arsenic

have been considered to be more toxic

than the organic forms. In toxicity tests,

the inorganic forms were reported to be

more toxic than the organic forms (NAS,

1977) and the trivalent form was more

toxic than the pentavalent one (Szinicz

and Forth, 1988).

In animals and humans, inorganic

pentavalent arsenic is converted to

trivalent arsenic that is methylated (i.e.,

chemically bonded to a methyl group,

which is a carbon atom linked to three

hydrogen atoms) to monomethyl arsenic

(MMA) and dimethyl arsinic acid

(DMA), which are organic arsenicals.

The primary route of excretion for these

four forms of arsenic is in the urine. The

organic arsenicals MMA and DMA were

once thought to be much less toxic than

inorganic arsenicals. 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). However, recent work has

shown that the assumption that organic

forms that arise during the metabolism

of inorganic arsenic are less toxic than

inorganic forms may not be correct

(Aposhian et al., 2000; Petrick et al.,

2000). One reason for this was that

earlier toxicity tests were conducted

using pentavalent MMA and DMA

because it was believed that trivalent

MMA(III) and DMA(III) were too

transient to be found in urine. Recently,

MMA(III) was isolated in human urine

(Aposhian et al., 2000). Tests have

demonstrated that MMA(III) is more

toxic to hepatocytes (i.e., liver cells) that

inorganic trivalent arsenic (Petrick et

al., 2000; Styblo et al., 2000). These

reports indicate that the metabolism of

inorganic arsenic is not necessarily a

detoxification process. As yet, it is not

known which form of arsenic

participates in the key events within

cells that disrupt cell growth control

and initiate or influence tumor

formation. The SAB noted that ‘‘[i]t is

not possible to consider contributions of

different forms of arsenic to the overall

response based on the data that are

available today’’ (EPA, 2000q).

b. 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

arsenic per kilogram (kg) of body weight

(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

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7001

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 U.S. public

water supplies in compliance with the

current MCL of 50 μg/L. EPA’s drinking

water regulation addresses the longterm, chronic effects of exposure to low

concentrations of inorganic arsenic in

drinking water.

c. Non-cancer effects associated with

arsenic. A large number of adverse

noncarcinogenic effects has 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 occur 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 (NRC, 1999, pg.

131). They include alterations in

pigmentation and the development of

keratoses that 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; NRC, 1999).

Chronic exposure to inorganic arsenic

is often associated with alterations in

gastrointestinal(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 standardized mortality ratios

(SMRs) for hypertensive heart disease

were noted in both males and females

after exposure to inorganic arseniccontaminated drinking water (Lewis et

al., 1999). These reports link exposure

to inorganic arsenic effects on the

cardiovascular system. 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 another

study in the U.S. (Engel et al., 1994), in

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

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 <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; Hopenhayn-Rich et al., 2000).

After reviewing the available literature

on arsenic and reproductive effects, the

NRC (1999) wrote that ‘‘nothing

conclusive can be stated from these

studies.’’ Regarding the HopenhaynRich study, the majority of the SAB

panel (EPA, 2000q) concluded that

while:

it is generally reasonable to consider that

children are generally at greater risk for a

toxic response to any agent in water because

of their greater drinking water consumption

(on a unit-body weight basis), [the SAB does

not] believe that this study demonstrates

such a heightened sensitivity or

susceptibility to arsenic.

The EPA agrees with this conclusion.

d. Cancers 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

hundreds of 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 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

(human studies) 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.

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 (Tseng et al., 1968). However,

the first studies that observed dosedependent 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.

7002 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

Physicians administered physical

examinations to the study group of over

40,000 residents from 37 villages, as

well as to a reference group of 7500

residents reported to be exposed to a

median level of 0 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

arsenic per liter (mg/L) measured at the

village level. A dose- and age-related

increase of arsenic-induced skin cancer

among the villagers was noted. No skin

cancers were observed in the low

arsenic reference areas. In both the EPA

1988 report on skin cancer and the 1999

NRC report, it was noted that grouping

individuals into broad exposure groups

(rather than grouping into village

exposures) limited the usefulness of

these studies for quantitative doseresponse estimation. 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 (EPA, 1984).

Internal cancers. Exposure to

inorganic arsenic in drinking water has

also been associated with the

development of internal cancers. Chen

et al. (1985) used 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

prostrate 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 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. The

best U.S. study currently available is

that of Lewis et al. (1999) who

conducted a mortality study of a

population in Utah whose drinking

water contained relatively low

concentrations of arsenic. 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

median (mid-point in range) community

exposure concentrations of 14 to 166

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. While the study

population males had a significantly

higher risk of prostate cancer mortality,

females had no significant excess 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.

Tsai et al. (1999) estimated SMRs 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. 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 et al. (1999)

population study had high arsenic

content. 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 et al.

(1999) used the single cause of death

noted on the death certificates. Many

chronic 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.

A small cohort study in Japan of

persons exposed to arsenic in drinking

water provides evidence of the

association of cancer and arsenic among

persons exposed for 5 years to 1000

μg/L or more and followed for 33 years

after cessation of exposure. The

strongest association was for lung and

bladder cancer, similar to results in

studies in Taiwan and South America

(Tsuda et al., 1995).

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

bladder cancer when exposure occurred

two to nine years prior to diagnosis.

Arsenic exposure occurring greater than

10 years prior to diagnosis was not

associated with bladder cancer risk.

This raises a question about the

significance of the finding about

exposures two to nine years since one

would expect earlier exposure to have

had an effect given the Tsuda et al.

(1995) study summarized previously.

The two internal cancers consistently

seen and best characterized in

epidemiologic studies are those of lung

and bladder. EPA considers the studies

summarized before as confirmation of

its long-standing view that arsenic is a

known human carcinogen. This rule

relies on assessment of lung and bladder

cancers for its quantitative risk

estimates in support of the MCL. EPA

recognizes that other internal cancers as

well as skin cancer are important.

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7003

Nonetheless, some issues with other

cancer endpoints led to their being

considered qualitatively rather than

quantitatively. EPA has considered skin

and liver cancer qualitatively for the

following reasons: (1) The skin cancer

endpoint is difficult to analyze because,

in the U.S., it is considered curable; and

(2) the liver cancer endpoint is likely to

have been influenced in Taiwan by the

prevalence there of viral hepatitis which

is a factor in liver cancer.

How does arsenic cause cancer? EPA

sponsored an ‘‘Expert Panel on Arsenic

Carcinogenicity: Review and

Workshop’’ in May 1997 (EPA, 1997e).

The panel evaluated existing data to

comment on arsenic’s carcinogenic

mode of action and the effect on doseresponse extrapolations. The panel

noted that arsenic compounds have not

formed deoxyribonucleic acid (DNA)

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

point mutations. Thus, indications are

that the mode of action does not involve

direct reaction with DNA. 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

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 that suggests

interference with DNA repair or cell

control instead of direct DNA damage.

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 (i.e., reduced

animal fats in the diet would

underestimate risk). 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 (EPA, 1997e, 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 (EPA, 1997e, page

31). On the other hand, basing risk

estimates on one or two tumor sites may

underestimate risk as compared to

summing risks for all related health

endpoints.

There is much research underway

about the mode of action for arsenic. In

order to understand the shape of the

dose-response relationship in the range

of exposure typical of the U.S., that is

significantly below the range of

observation of epidemiologic studies,

one needs to identify which one or more

of the possible modes of action is

operative. If this can be elucidated, it

will become possible to study and

quantify the key events within cells that

influence cell growth control and how

they may quantitatively relate to

eventual tumor incidence. Until then

the shape of the dose-response

relationship and whether there is any

threshold cannot be known.

f. What is the quantitative

relationship between exposure and

cancer effects that may be projected for

exposures in the U.S.? The Agency

chose to make its quantitative estimates

of risk based on the Chen et al. (1988;

1992) and Wu et al. (1989) Taiwan

studies. This choice was endorsed by

the NRC and EPA’s SAB (EPA, 2000q;

NRC, 1999). The database from Taiwan

has the following advantages: mortality

data were drawn from a cancer registry;

arsenic well water concentrations were

measured for each of the 42 villages;

there was a large, relatively stable study

population that had life-time exposures

to arsenic; there are limited measured

data for the food intake of arsenic in this

population; age- and dose-dependent

responses with respect to arsenic in the

drinking water were demonstrated; the

collection of pathology data was

unusually thorough; and the

populations were quite homogeneous in

terms of lifestyle.

EPA recognizes that there are

problems with the Taiwan study that

introduce uncertainties to the risk

analysis such as: the use of median

exposure data at the village level; the

low income and relatively poor diet of

the Taiwanese study population (high

levels of carbohydrates, low levels of

protein, selenium and other essential

nutrients); and high exposure to arsenic

via food and cooking water. These are

discussed more thoroughly in the

following paragraphs. The available

studies from Taiwan are ecological

studies and have exposure uncertainties

that are recognized. Ecological studies

are problematic as bases for quantitative

risk assessment. Errors in assigning

persons to exposures are difficult to

avoid. Moreover, all confounding factors

that may have contributed to risk may

not be adequately accounted for. These

uncertainties have to be remembered

since they lead to uncertainty in the

quantitative dose-response relationship

estimated in the observed range of data

and in any extrapolation to estimate the

potential risk at exposures significantly

below the observed range. There is not

a way to take all confounding factors

into account quantitatively. (see section

III.F.)

Notwithstanding these concerns, the

Taiwan epidemiological studies provide

the basis for assessing potential risk

from lower concentrations of inorganic

arsenic in drinking water, without

having to adjust for cross-species

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 do not respond to inorganic

arsenic exposure in a way that makes

them useful as a model for human

cancer assessment. Their metabolism of

inorganic arsenic is also quantitatively

different than humans.

There are issues with the

extrapolation of the dose-response from

the observed range of exposure in

Taiwan to estimate Taiwan cancer risk

below the observed data range and

application of the same risk estimate to

U.S. populations. The following issues

have been addressed:

• The Taiwan population ingested

more arsenic in food and via cooking

with contaminated water than is typical

for the U.S. population. This is because

the staples of the Taiwan diet were rice

and sweet potatoes. Rice and sweet

potatoes are high in arsenic and both

staples absorb water upon cooking. EPA

did a sensitivity analysis of the effect of

exposure to arsenic through water used

in preparing food in Taiwan. EPA also

analyzed the effect of exposure to

arsenic through food.

• The Taiwan data on exposure were

uncertain because the association of

individuals with contaminated wells

was made by grouping persons in a

village and assuming they had a lifetime

of exposure to the median of the

concentration of arsenic measured in

the wells serving that village. Wells

within each village had varying arsenic

levels so that people using certain wells

had much higher exposures than others

in the same village. Not all wells serving

all villages were measured. However, all

villagers were assigned a single median

7004 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

concentration for exposure. In addition,

moves made from village to village were

not accounted for. When villages with

only one arsenic measurement were

removed from the data set (on the theory

that the exposure data were too

uncertain), or when village means

instead of medians were used for the

exposure estimates, there was no

statistically significant change in the

estimated point of departure, using

Model 1 of Morales et al. (2000).

• The Taiwan population was a rural

population that was not well nourished,

having deficits of selenium, possibly

methionine or choline (methyl donors),

zinc and other essential nutrients. This

malnourishment is not typical of the

U.S. population, although some U.S.

populations may have one or another of

the same deficits. The Taiwanese

population may also have some genetic

differences from the general U.S.

population. These issues cannot be

quantitatively accounted for. However,

deficits in selenium in the diet, in

particular, are a known risk factor for

cancer and indicate possible

overestimation of risk when the Taiwan

data are applied. EPA has qualitatively

taken this into account. (See section

III.F.)

• The Utah study (Lewis et al., 1999)

did not find any excess bladder or lung

cancer risk after exposure to arsenic at

concentrations of 14 to 166 μg/L. An

important feature of the study is that it

estimated excess risk by comparing

cancer rates among the study

population, in Millard County, Utah to

background rates in all of Utah. But the

cancer rates observed among the study

population, even those who consumed

the highest levels of arsenic, were lower,

in many cases significantly lower, than

in all of Utah. This is evidence that

there are important differences between

the study and comparison populations

besides their consumption of arsenic.

One such difference is that Millard

County is mostly rural, while Utah as a

whole contains some large urban

populations. Another difference is that

the subjects of the Utah study were all

members of the Church of Jesus Christ

of Latter Day Saints, who for religious

reasons have relatively low rates of

tobacco and alcohol use. For these

reasons, the Agency believes that the

comparison of the study population to

all of Utah is not appropriate for

estimating excess risks. An alternative

method of analysis is to compare cancer

rates only among people within the

study population who had high and low

exposures. The Agency performed such

an analysis on the Utah data, using the

statistical technique of Cox proportional

hazard regression (US EPA, 2000x; Cox

and Oakes, 1984). The results showed

no detectable increased risk of lung or

bladder cancers due to arsenic, even

among subjects exposed to more than

100 μg/L on average. On the other hand,

the excess risk could also not be

distinguished statistically from the

levels predicted by model 1 of Morales

et al. (2000). What these results show is

that the Utah study is not powerful

enough to estimate excess risks with

enough precision to be useful for the

Agency’s arsenic risk analysis.

Furthermore, the SAB noted that

‘‘(a)lthough the data provided in

published results of the Lewis, et al.,

1999 study imply that there was no

excess bladder or lung cancer in this

population, the data are not in a form

that allows dose-response to be assessed

dependably’’ (EPA, 2000q). The

indications of Lewis et al. study have

been taken into account in the

judgments of the impact of scientific

uncertainties on the final MCL.

g. Is it appropriate to assume linearity

for the dose-response assessment for

arsenic at low doses given that arsenic

is not directly reactive with DNA?

Independent scientific panels (EPA,

2000q; NRC, 1999; EPA, 1997e; EPA,

1988) who have considered the Taiwan

study have raised the caution that using

the Taiwan study to estimate U.S. risk

at lower levels may result in an overly

conservative estimation of U.S. risk. The

independent panels have each said that

below the observed range of the high

level of contamination in Taiwan the

shape of the dose-response relationship

may prove to be sublinear when there is

adequate data to characterize the mode

of action. If so, an assumption that the

effects seen per dose increment remain

the same from high to low levels of dose

may overstate the U.S. risk. In

evaluating the benefits of alternative

MCLs, EPA weighed both the qualitative

and quantitative uncertainties about risk

magnitude (see section III.F.)

The use of a linear procedure to

extrapolate from a higher, observed data

range to a lower range beyond

observation is a science policy approach

that has been in use by Federal agencies

for four decades. Its basis is both science

and policy. The policy objectives are to

avoid underestimating risk in order to

protect public health and be consistent

and clear across risk assessments. The

science components include its

applicability to generally available data

sets (animal tests and human studies)

and its basis in the fact that cancer is a

consequence of genetic changes coupled

with the assumption that direct reaction

with DNA is a basic mode of action for

chemicals causing important genetic

changes (Cogliano et al., eds., 1999).

The linear approach is intended to

identify a level of risk that is an upper

limit on what the risk might be. There

are two biological situations in which

the linear approach can be a particularly

uncertain estimate of risk. One is when

the metabolism and toxicokinetics of the

agent being assessed cause a nonlinear

relationship between the dose of the

active form and the dose of the applied

form of the agent. If this is not

quantitatively dealt with in the dose

part of the dose-response estimation, the

linear extrapolation will have added

uncertainties. In the case of arsenic, it

is known that metabolism and

toxicokinetics are complex, but the

active form(s) is not known. The

resulting complexities of estimating

dose cannot, therefore, be accounted for

in dose-response modeling.

The other situation is when the mode

of action of the agent is indirect; that is,

when there is not a one-to-one reaction

between the active form of the agent and

DNA, but, instead, the active form

affects other cell components or

processes that, in turn, causes genetic

change. In such cases, the rates of these

secondary processes are limiting, not

the dose of the active form. With few

exceptions, the rates of these secondary

processes are thought not to be a linear

function of applied dose. In the case of

arsenic, it is known that arsenic does

cause genetic changes in short-term

tests, but these are indirect genetic

changes (not one-to-one reactions

between arsenic and DNA).

If there are both complex

toxicokinetics and secondary effects, the

upper-limit risk estimate from the linear

approach provides may be overly

conservative. However, there simply are

not sufficient data to quantify the effect

of these two features of arsenic on risk.

While some commenters assert that the

Agency can simply use models that

have sublinear structures to address the

issue of secondary nature of effects, the

Agency does not agree. There are no

data on the effects of arsenic that may

be precursors to cancer. Without such

biological data, the exercise of blindly

applying models has no anchor, in

EPA’s judgment. Such modeled

extrapolations could take numerous

shapes and there is no way to decide

how shallow or steep the curve would

be or where on the dose gradient the

zero risk level might be, given the

hundreds of possibilities. There are also

certain modes of action that do not

involve DNA reactivity, but are thought

to be linear in dose response, such as

effects on growth-control signals within

cells. Since we do not know what the

mode of action of arsenic is, we cannot

in fact rule out linearity. Therefore, in

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7005

accordance with the 1986 cancer

guidelines, and subsequent guidance

discussed later, the Agency cannot

reasonably use anything other than a

linear mode of action to estimate the

upper bound of risk associated with

arsenic exposure. Nevertheless, the

uncertainties about both of these facets

(the toxicokinetics and secondary

effects) of risk estimation have been

taken into account qualitatively in the

Agency’s final decision as a perspective

on the linear dose-response estimation

(see section III.F.).

The Agency considered mode-ofaction information as a basis for

departing from the assumption of

linearity and in the process, developed

a framework for judging the adequacy of

mode of action data (EPA, 1996a). This

framework has been reviewed and

supported by the SAB (EPA, 1997f; EPA,

1999g). The framework was applied to

the assessment of chloroform (EPA,

2000d).

In order to decide whether a

particular mode of action is operative

for an agent, the database on mode of

action must be rich and able to both

describe the sequence of key events in

the putative mode of action and

demonstrate it experimentally. The

elements of the framework analysis

include:

• Summary description of postulated

mode of action (the postulated sequence

of cellular/physiological events leading

to cancer must be described.)

• Identification of key events (the

specific events that are key to

carcinogenesis must described in order

to be experimentally examined.)

• Strength, consistency, specificity of

association (the experimental

observation of the key events and their

relationship to tumor development must

be described.)

• Dose-response relationship (the

dose-response relationship between the

key events and tumor incidence must be

described and evaluated.)

• Temporal relationship (the key

events must be shown to precede tumor

development.)

• Biological plausibility and

coherence (the postulated mode of

action and the data must be in accord

with general, accepted scientific

evidence about the causes of cancer.)

• Other modes of action (alternative

modes of action that are suggested must

be examined and their contribution, if

any, described.)

• Conclusion (an overall conclusion

is made as to whether the postulated

mode of action is accurate given the

results of evaluation of the evidence

under the previous elements.)

• Human relevance, including

subpopulations (if the evidence of mode

of action of carcinogenicity is from

animal studies, its human relevance is

examined.)

In the case of chloroform, there was

sufficient information to describe key

events and undertake mode of action

analysis. In the case of arsenic, the

postulated mode of action cannot be

specifically described, the key events

are unknown, and no analysis of the

remaining elements of the mode of

action framework can be made. Several

possible influences of arsenic on the

carcinogenic process have been

postulated, but there are insufficient

experimental data either to show that

any one of the possible modes is the

influence actually at work or to test the

dimensions of its influence as the

framework requires.

For chloroform there are extensive

data on metabolism that identify the

likely active metabolite. The key

events—cell toxicity followed by

sustained cell proliferation and

eventually tumor effects—have been

extensively studied in many

experiments. The key events have been

empirically demonstrated to precede

and consistently be associated with

tumor effects. In sum, a very large

number of studies have satisfied the

requirements of the framework analysis.

By contrast, the arsenic database fails to

even be able to satisfy the first element

of the framework; the key events are

unknown. While there are a number of

possible modes of action implied by

existing data, none of them has been

sufficiently studied to be analyzed

under the Agency’s framework. For this

reason the comparison of the ‘‘best

available, peer reviewed data’’ for

arsenic and chloroform shows quite

different results. There are not sufficient

data on arsenic to describe a mode of

action as there were for chloroform.

This was also the conclusion of the SAB

review of arsenic (EPA, 2000q).

Overall, the NRC and SAB reports

agreed that the best available science

provides no alternative to use of a linear

dose-response process for arsenic

because a specific mode (or modes) of

action has not been identified. Unlike

chloroform, the Agency lacks sufficient

available, peer-reviewed information on

arsenic to estimate quantitatively a nonlinear mode of action. The Agency thus

has decided not to depart from the

assumption of linearity in selecting an

MCLG of zero.

2. Risk factors/bases for upper- and

lower-bound analyses

EPA calculated upper- and lowerbound risk estimates for the U.S.

population exposed to arsenic

concentrations. The approach for this

analysis included five components.

First, we developed relative exposure

factor distributions, which incorporate

data from the recent EPA water

consumption study with age, sex, and

weight data. Second, the Agency

calculated the arsenic occurrence

distributions for the population exposed

to arsenic levels above 3 μg/L. Third, we

chose risk distributions for bladder and

lung cancer for the analysis from

Morales et al. (2000). Fourth, EPA

developed estimates of the projected

bladder and lung cancer risks faced by

exposed populations using Monte-Carlo

simulations, bringing together the

relative exposure factor, occurrence, and

risk distributions. These simulations

resulted in upper bound estimates of the

risks faced by U.S. populations exposed

to arsenic concentrations at or above 3

μg/L in their drinking water. Finally,

EPA made adjustments to the lowerbound risk estimates to reflect exposure

to arsenic in cooking water and in food

in Taiwan. A more detailed description

of the risk methodology is provided in

Appendix B of the Economic Analysis

(EPA, 2000o).

a. Water consumption. EPA recently

updated its estimates of per capita daily

average water consumption (EPA,

2000c). 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, multi-stage area

probability sample of the entire U.S. and

is conducted to survey the food and

beverage intake of the U.S. 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

7006 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

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 the 90th percentile of daily

average per capita consumption of total

water is 2.3 liters/person/day. In other

words, current consumption data

indicate that 90% of the U.S. population

consumes approximately 2 liters/

person/day, or less.

Water consumption estimates for

selected subpopulations in the U.S. are

described in the CSFII, 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 and sex

were used in the computation of the

relative exposure factors discussed later.

b. Relative Exposure Factors. Lifetime

male and female relative exposure

factors (REFs) for each of the broad age

categories used in the water

consumption study were calculated,

where the life-long REFs indicate the

sensitivity of exposure to an individual

relative to the sensitivity of exposure of

an ‘‘average’’ person weighing 70

kilograms and consuming 2 liters of

water per day, a ‘‘high end’’ water

consumption estimate according to the

EPA water consumption study referred

to previously (EPA, 2000c). In these

calculations, EPA combined the water

consumption data with data on

population weight from the 1994

Statistical Abstract of the U.S.

Distributions for both community tap

water and total water consumption were

used because the community tap water

estimates may underestimate actual tap

water consumption. The weight data

included a mean and a distribution of

weight for male and females on a yearto-year basis. The means and standard

deviations of the life-long REFs derived

from this analysis are shown in Table

III.D–1.

TABLE III.D–1.—LIFE-LONG RELATIVE EXPOSURE FACTORS

Community water consumption data Total water consumption data

Male .................. Mean = 0.60 ..............................................................................

s.d. = 0.61 .................................................................................

Mean = 0.73

s.d. = 0.62

Female ............. Mean = 0.64 ..............................................................................

s.d. = 0.6 ...................................................................................

Mean = 0.79

s.d. = 0.61

c. Arsenic occurrence. EPA recently

updated its estimates of arsenic

occurrence, and calculated separate

occurrence distributions for arsenic

found in ground water and surface

water systems. These occurrence

distributions were calculated for

systems with arsenic concentrations of 3

μg/L or above. Arsenic occurrence

estimates are described in more detail in

section III.C.

d. Risk distributions. 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 had

comparable risks to those ‘‘in Taiwan at

comparable levels of exposure’’ (NRC,

1999). The NRC also examined the

implications of applying different

statistical analyses to the newly

available Taiwanese data for the

purpose of characterizing bladder

cancer risk. 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 the June 22, 2000

proposed rule, EPA calculated bladder

cancer risks and benefits using the

bladder cancer risk analysis from the

NRC report (NRC, 1999). We also

estimated lung cancer benefits in a

‘‘What If’’ analysis based on the

statement in the 1999 NRC report 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).

In July, 2000, a peer reviewed article

by Morales et al. (2000) was published,

which presented additional analyses of

bladder cancer risks as well as estimates

of lung and liver cancer risks for the

same Taiwanese population analyzed in

the NRC report. EPA summarized and

analyzed the new information from the

Morales et al. (2000) article in a NODA

published on October 20, 2000 (65 FR

63027; EPA, 2000m). Although the data

used were the same as used by the NRC

to analyze bladder cancer risk in their

1999 publication, Morales et al. (2000)

considered more dose-response models

and evaluated how well they fit the

Taiwanese data for both bladder cancer

risk and lung cancer risk. Ten risk

models were presented in Morales et al.

(2000) used with and without one of

two comparison populations. After

consultation with the primary authors

(Morales and Ryan), EPA chose Model

1 with no comparison population for

further analysis.

EPA believes that the models in

Morales et al. (2000) without a

comparison population are more

reliable than those with a comparison

population. Models with no comparison

population estimate the arsenic doseresponse curve only from the study

population. Models with a comparison

population include mortality data from

a similar population (in this case either

all of Taiwan or part of southwestern

Taiwan) with low arsenic exposure.

Most of the models with comparison

populations resulted in dose-response

curves that were supralinear (higher

than a linear dose response) at low

doses. The curves were ‘‘forced down’’

near zero dose because the comparison

population consists of a large number of

people with low risk and low exposure.

EPA believes, based on discussions with

the authors of Morales et al. (2000), that

models with a comparison population

are less reliable, for two reasons. First,

there is no basis in data on arsenic’s

carcinogenic mode of action to support

a supralinear curve as being biologically

plausible. To the contrary, the

conclusion of the NRC panel (NRC,

1999) was that the mode of action data

led one to expect dose responses that

would be either linear or less than linear

at low dose. However, the NRC

indicated that available data are

inconclusive and ‘‘ * * * do not meet

EPA’s 1996 stated criteria for departure

from the default assumption of

linearity.’’ (NRC, 1999)

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7007

Second, models that include

comparison populations assume that the

study and comparison populations are

the same in all important respects

except for arsenic exposure. Yet Morales

et al. (2000) agree that ‘‘[t]here is reason

to believe that the urban Taiwanese

population is not a comparable

population for the poor rural population

used in this study.’’ Moreover, because

of the large amount of data in the

comparison populations, the model

results are sensitive to assumptions

about this group. Evidence that supports

these arguments are that the risks in the

comparison groups are substantially

lower than in similarly exposed

members of the study group and the

shape of the estimated dose-response

changes sharply as a result. For these

reasons, EPA believes that the models

without comparison populations are

more reliable than those with them. Of

the models that did not include a

comparison population, EPA believes

that Model 1 best fits the data, based on

the Akaike Information Criterion (AIC),

a standard criterion of model fit, applied

to Poisson models. In Model 1, the

relative risk of mortality at any time is

assumed to increase exponentially with

a linear function of dose and a quadratic

function of age.

Morales et al. (2000) reported that two

other models without comparison

populations also fit the Taiwan data

well: Model 2, another Poisson model

with a nonparametric instead of

quadratic age effect, and a multi-stage

Weibull (MSW) model. Under Model 2,

the points of departure for male and

female bladder and lung cancer are from

1% to 11% lower than under Model 1,

but within the 95% confidence bounds

from Model 1. Model 2 therefore implies

essentially the same bladder and lung

cancer risks as Model 1. Under the

MSW model, compared to Model 1,

points of departure are 45% to 60%

higher for bladder cancer and for female

lung cancer, and 38% lower for male

lung cancer. EPA did not consider the

MSW model for further analysis,

because this model is more sensitive to

the omission of individual villages

(Morales et al., 2000) and to the

grouping of responses by village (NRC,

1999), as occurs in the Taiwanese data.

However, if the MSW model were

correct, it would imply a 14% lower

combined risk of lung and bladder

cancers than Model 1, among males and

females combined.

Considering all of these results, the

Agency decided that the more

exhaustive statistical analysis of the

data provided by Morales et al. (2000),

as analyzed by EPA, would be the basis

for the new risk calculations for the

final rule (with further consideration of

additional risk analyses) and other

pertinent information. The Agency

views the results of the alternative

models described above as an additional

uncertainty which was considered in

the decision concerning the selection of

the final MCL (see section III.F. of

today’s preamble).

e. Estimated risk reductions.

Estimated risk reductions for bladder

and lung cancer at various MCL levels

were developed using Monte-Carlo

simulations. Monte-Carlo analysis is a

technique for analyzing problems where

there are a large number of

combinations of input values which

makes it impossible to calculate every

possible result. A random number

generator is used to select input values

from pre-defined distributions. For each

set of random numbers, a single

scenario’s result is calculated. As the

simulation runs, the model is

recalculated for each new scenario that

continues until a stopping criteria is

reached. These simulations combined

the distributions of relative exposure

factors (REFs), occurrence at or above 3

μg/L, and risks of bladder and lung

cancer taken from the Morales et al.

(2000) article. The simulations resulted

in upper-bound estimates of the actual

risks faced by populations exposed to

arsenic concentrations at or above 3 μg/

L in their drinking water.

f. Lower-bound analyses. Two

adjustments were made to the risk

distributions resulting from the

simulations described previously,

reflecting uncertainty about the actual

arsenic exposure in the Taiwan study

area. First, the Agency made an

adjustment to the lower bound risk

estimates to take into consideration the

effect of exposure to arsenic through

water used in preparing food in Taiwan.

The Taiwanese staple foods were dried

sweet potatoes and rice (Wu et al.,

1989). Both the 1988 EPA ‘‘Special

Report on Ingested Inorganic Arsenic’’

report (EPA,1988) and the 1999 NRC

report assumed that an average

Taiwanese male weighed 55 kg and

drank 3.5 liters of water daily, and that

an average Taiwanese female weighed

50 kg and drank 2 liters of water daily.

Using these assumptions, along with an

assumption that Taiwanese men and

women ate one cup of dry rice and two

pounds of sweet potatoes a day, the

Agency re-estimated risks for bladder

and lung cancer, using one additional

liter water consumption for food

preparation (i.e., the water absorbed by

hydration during cooking). This

adjustment was discussed and used in

the October 20, 2000 NODA (65 FR

63027; EPA, 2000m).

Second, an adjustment was made to

the lower-bound risk estimates to take

into consideration the relatively high

arsenic concentration in the food

consumed in Taiwan as compared to the

U.S. The food consumed daily in

Taiwan contains about 50 μg of arsenic,

versus about 10 μg in the U.S. (NRC,

1999, pp. 50–51). Thus the total

consumption of inorganic arsenic (from

food preparation and drinking water) is

considered, per kilogram of body

weight, in the process of these

adjustments. To carry them out, the

relative contribution of arsenic in the

drinking water that was consumed as

drinking water, on a μg arsenic per

kilogram body weight per day (μg/kg/

day) basis, was compared to the total

amount of arsenic consumed in drinking

water, drinking water used for cooking,

and in food, on a μg/kg/day basis.

Other factors contributing to lower

bound uncertainty include the

possibility of a sub-linear dose-response

curve below the point of departure. The

NRC noted ‘‘Of the several modes of

action that are considered most

plausible, a sub-linear dose response

curve in the low-dose range is

predicted, although linearity cannot be

ruled out.’’ (NRC, 1999). The recent

Utah study (Lewis et al., 1999),

described in section V.G.1(b), provides

some evidence that the shape of the

dose-response curve may well be sublinear at low doses. Because sufficient

mode of action data were not available,

an adjustment was not made to the risk

estimates to reflect the possibility of a

sub-linear dose-response curve.

Additional factors contributing to

uncertainty include the use of village

well data rather than individual

exposure data, deficiencies in the

Taiwanese diet relative to the U.S. diet

(selenium, choline, etc.), and the

baseline health status in the Taiwanese

study area relative to U.S. populations.

The Agency did not make adjustments

to the risk estimates to reflect these

uncertainties because applicable peerreviewed, quantitative studies on which

to base such adjustments were not

available.

Estimated risk levels for bladder and

lung cancer combined at various MCL

levels are shown in Tables III.D–2(a-c).

The risk estimates without adjustments

for exposure uncertainty through

cooking water and food are shown Table

III.D–2 (a). These estimates incorporate

occurrence data, water consumption

data, and male and female risk

estimates. Lower bounds show estimates

using community water consumption

data; upper bounds show estimates

using total water consumption data.

Table III.D–2 (b) shows estimated risk

7008 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

levels for bladder and lung cancer

combined at various MCL levels with

adjustments for exposure uncertainty

through cooking water and food. These

estimates incorporate occurrence data,

water consumption data, and male risk

estimates, with lower bounds reflecting

community water consumption data and

upper bounds reflecting total water

consumption data. There are no

adjustments for other factors which

contribute to uncertainty, such as the

use of village well data as opposed to

individual exposure data. Tablet III.D–2

(c) is a combination of Table III.D–2(a)

and Table III.D–2 (b), with the lower

bounds taken from Table III.D–3 (b), and

the upper bounds taken from Table

III.D–2 (a). Thus Table III.D–2(c) reflects

the range of estimates before and after

the exposure uncertainty adjustments

for cooking water and for food, along

with the incorporation of water

consumption data, occurrence data, and

cancer risk estimates. These estimates

were used to estimate the range of

potential cases avoided at the various

MCL levels.

The lower-bound risk estimates in

Tables III.D–2(a-c) reflect the following:

—The community (tap) water

consumption from the EPA water

consumption study (EPA, 2000c)

—The occurrence distributions of

arsenic in U.S. ground and surface

water systems

—Male risk estimates from Morales et

al. (2000)

—Arsenic exposure from cooking water

in Taiwan

—Arsenic exposure from food in

Taiwan

The upper-bound risk estimates in

Tables III.D–2(a-c) reflect the following:

—The total water consumption

estimates from the EPA water

consumption study (EPA, 2000c)

—The occurrence distributions of

arsenic in U.S. ground and surface

water systems

—Male and female risk estimates from

Morales et al. (2000)

TABLE III.D–2(a).—CANCER RISKS FOR U.S. POPULATIONS EXPOSED AT OR ABOVE MCL OPTIONS, AFTER

TREATMENT 1,2

[without adjustment for arsenic in food and cooking water]

MCL

(μg/L)

Mean exposed

population risk

90th percentile exposed

population risk

3 ............................................................................................................................................... 0.93 –1.25 × 10¥4 1.95 –2.42 × 10¥4

5 ............................................................................................................................................... 1.63 –2.02 × 10¥4 3.47 –3.9 × 10¥4

10 ............................................................................................................................................. 2.41 –2.99 × 10¥4 5.23 –6.09 × 10¥4

20 ............................................................................................................................................. 3.07 –3.85 × 10¥4 6.58 –8.37 × 10¥4

1Actual risks could be lower, given the various uncertainties discussed, or higher, as these estimates assume that the probability of illness

from arsenic exposure in the U.S. is equal to the probability of death from arsenic exposure among the arsenic study group. 2The estimated risks are male and female risks combined.

TABLE III.D–2(B).—CANCER RISKS FOR U.S. POPULATIONS EXPOSED AT OR ABOVE MCL OPTIONS, AFTER

TREATMENT 1, 2

[without adjustment for arsenic in food and cooking water]

MCL

(μg/L)

Mean exposed

population risk

90th percentile exposed

population risk

3 ............................................................................................................................................... 0.11 –0.13 × 10¥4 0.22 –0.26 × 10¥4

5 ............................................................................................................................................... 0.27 –0.32 × 10¥4 0.55 –0.62 × 10¥4

10 ............................................................................................................................................. 0.63 –0.76 × 10¥4 1.32 –1.54 × 10¥4

20 ............................................................................................................................................. 1.1 –1.35 × 10¥4 2.47 –2.89 × 10¥4

1Actual risks could be lower, given the various uncertainties discussed, or higher, as these estimates assume that the probability of illness

from arsenic exposure in the U.S. is equal to the probability of death from arsenic exposure among the arsenic study group. 2The estimated risks are for males.

TABLE III.D–2(c).—CANCER RISKS FOR U.S. POPULATIONS EXPOSED AT OR ABOVE MCL OPTIONS, AFTER TREATMENT 1,2

[lower bound with food and cooking water adjustment, upper bound withough food and cooking water adjustment]

MCL

(μg/L)

Mean exposed

population risk

90th percentile exposed

population risk

3 ............................................................................................................................................... 0.11 –1.25 × 10¥4 0.22 –2.42 × 10¥4

5 ............................................................................................................................................... 0.27 –2.02 × 10¥4 0.55 –3.9 × 10¥4

10 ............................................................................................................................................. 0.63 –2.99 × 10¥4 1.32 –6.09 × 10¥4

20 ............................................................................................................................................. 1.1 –3.85 × 10¥4 2.47 –8.37 × 10¥4

1Actual risks could be lower, given the various uncertainties discussed, or higher, as these estimates assume that the probability of illness

from arsenic exposure in the U.S. is equal to the probability of death from arsenic exposure among the arsenic study group.

g. Cases avoided. The lower and

upper bound risk estimates from Table

III.D–2(c) were applied to the exposed

population to generate cases avoided for

CWSs serving less than a million

customers. Because the actual arsenic

occurrence was known for the very large

systems (those serving over a million

customers), their system-specific arsenic

occurrence distributions could be

directly computed. The system-specific

arsenic distributions allowed direct

calculation of avoided cancer cases. The

process, described in detail in the

Economic Analysis (EPA, 2000o),

utilizes the same risk estimates from

Morales et al. (2000) that were used in

deriving the number of cases avoided in

smaller CWSs. Cases avoided for

NTNCWSs were also computed

separately, utilizing factors developed to

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7009

account for the intermittent nature of

the exposure. These factors are

described in the Economic Analysis.

An upper-bound adjustment was

made to the number of bladder cancer

cases avoided to reflect a possible lower

mortality rate in Taiwan than was

assumed in the risk assessment process

described earlier. We also made this

adjustment in the June 22, 2000

proposal. In the Taiwan study area,

information on arsenic-related bladder

and lung cancer deaths was reported. In

order to use these data to determine the

probability of contracting bladder and

lung cancer as a result of exposure to

arsenic, a probability of mortality, given

the onset of arsenic-induced bladder

and lung cancer among the Taiwanese

study population, must be assumed. The

study area in Taiwan is a section where

arsenic concentrations in the water are

very high by comparison to those in the

U.S., and an area of low incomes and

poor diets, where 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 probability of

contracting bladder cancer was

relatively close to the probability of

dying from bladder cancer (i.e., that the

bladder cancer incidence rate was equal

to the bladder cancer mortality rate).

We do not have data on the rates of

survival for bladder cancer in the

Taiwanese villages in the study 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 (WHO, 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 (i.e., 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. 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 previous

discussion, we think bladder cancer

incidence could be no more than twofold bladder cancer mortality; and that

an 80% mortality rate would be

plausible. Thus, we have adjusted the

upper bound of cases avoided, which is

used in the benefits analysis, to reflect

a possible mortality rate for bladder

cancer of 80 percent. Because lung

cancer mortality rates are quite high,

about 88% in the U.S. (EPA, 1998n), the

assumption was made that all lung

cancers in the Taiwan study area

resulted in fatalities.

The total number of bladder and lung

cases avoided at each MCL is shown in

Table III.D–3. These cases avoided

include CWSs and NTNCWSs cases.

The number of bladder and lung cancer

cases avoided ranges from 57.2 to 138.3

at an MCL of 3 μg/L, 51.1 to 100.2 at an

MCL of 5 μg/L, 37.4 to 55.7 at an MCL

of 10 μg/L, and 19.0 to 19.8 at an MCL

of 20 μg/L. The cases avoided were

divided into premature fatality and

morbidity (i.e., illness) cases based on

U.S. mortality rates. 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 (EPA,

1999j). 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 was 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% from 1973 to 1996. For lung

cancer, mortality rates are much higher.

The comparable mortality rate for lung

cancer in the U.S. is 88% (EPA, 1998n).

TABLE III.D–3.—ANNUAL TOTAL (BLADDER AND LUNG) CANCER CASES AVOIDED FROM REDUCING ARSENIC IN CWSS

AND NTNCWS

Arsenic level (μg/L)

Reduced

mortality

cases1

Reduced

morbidity

cases1

Total cancer

cases

avoided

3 ............................................................................................................................................................... 32.6–74.1 24.6–64.2 57.2–138.3

5 ............................................................................................................................................................... 29.1–53.7 22.0–46.5 51.1–100.2

10 ............................................................................................................................................................. 21.3–29.8 16.1–25.9 37.4–55.7

20 ............................................................................................................................................................. 10.2–11.3 8.5–8.8 19.0–19.8

1Based on U.S. mortality rates given in the text.

3. Sensitive Subpopulations

The 1996 SDWA amendments include

specific provisions in section

1412(b)(3)(C)(i)(V) that require EPA to

assess the effects of a contaminant not

just on the general population but on

groups within the general population

such as infants, children, pregnant

women, the elderly, individuals with a

history of serious illness, or other

subpopulations 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 subcommittee

noted that there is a marked variation in

susceptibility to arsenic-induced toxic

effects that may be influenced by factors

such as genetic polymorphisms

(especially in metabolism), life stage at

which exposures occur, sex, nutritional

status, and concurrent exposures to

other agents or environmental factors.

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. EPA

agrees with the NRC that there is not

enough information to make risk

conclusions on any specific

subpopulations.

4. Risk Window

EPA has historically considered 10¥4

to 10¥6 as a target risk range protective

of public health in its drinking water

program. However, the risk-range

7010 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

represents a policy goal for EPA, and is

not a statutory factor in setting an MCL.

Note that the procedure EPA uses to

estimate such risks provides an upperbound estimate. In the case of arsenic,

EPA performed a benefit-cost analysis as

required by the statute. This analysis is

discussed in more detail in section III.F.

E. What Are the Costs and Benefits at 3,

5, 10, and 20 μg/L?

In accordance with section 1412

(b)(3)(C) of SDWA, EPA must analyze

the costs and benefits of a proposed

NPDWR. To comply with this provision,

EPA included the complete analysis in

the proposed rule. Also, in accordance

with Executive Order 12866, Regulatory

Planning and Review, EPA must

estimate the costs and benefits of the

arsenic rule in an Economic Analysis in

conjunction with publishing the final

rule. EPA has prepared an Economic

Analysis to comply with the

requirements of this Order. This section

provides a summary of the information

from the Arsenic Economic Analysis

(EPA, 2000o).

1. Summary of Cost Analysis

National cost estimates of compliance

with the arsenic rule were derived from

estimates of utility treatment costs,

monitoring and reporting costs, and

start-up costs for both CWS and

NTNCWSs. Utility treatment costs were

derived using occurrence data,

treatment train unit costs, and decision

trees. The occurrence data provide a

measure of the number of systems that

would need to install treatment in each

size category. The treatment train unit

cost estimates provide a measure of how

much a technology will cost to install.

Decision trees vary by system size and

are used as a prediction of the treatment

technology trains facilities would likely

install to comply with options

considered for the revised arsenic

standard. Detailed descriptions of the

methodologies used in determining the

costs of this rule are found in the

‘‘Technologies and Cost for Removal of

Arsenic in Drinking Water’’ document

(EPA, 2000t) and also the ‘‘Arsenic

Economic Analysis’’ (EPA, 2000o), both

of which are in the docket for this final

rulemaking.

a. Total national costs. Under the

MCL of 10 μg/L, the Agency estimates

that total national costs to CWSs are

$172.3 million (1999 dollars) annually

at a 3% discount rate. This total

national cost includes annual treatment

costs ($169.6 million), annual

monitoring and administrative costs

($1.8 million), and annual State costs

($0.9 million). Assuming a 7% discount

rate, total national costs to CWSs are

estimated at $196.6 million annually.

Total national costs to NTNCWSs are

estimated at $8.1 million annually at a

3% discount rate. This includes annual

treatment costs ($7.0 million), annual

monitoring and administrative costs

($0.9 million), and annual State costs

($0.1 million). Total national costs to

NTNCWSs, assuming a 7% discount

rate, are estimated at $9.1 million

annually.

Table III.E–1 shows the total national

cost breakdown for the arsenic MCL and

also for three other arsenic levels

considered in the proposed rule.

Expected system costs include treatment

costs, monitoring costs, and

administrative costs of compliance.

State costs include monitoring and

administrative costs of implementation.

As expected, aggregate arsenic

compliance costs increase with

decreasing arsenic MCL levels as more

systems are affected.

TABLE III.E–1.—TOTAL ANNUAL NATIONAL SYSTEM AND STATE COMPLIANCE COSTS

[$ millions, 1999]

Discount rate

CWS NTNCWS Total

3 percent 7 percent 3 percent 7 percent 3 percent 7 percent

MCL = 3 μg/L

System Costs ................................................................... $668.1 $759.5 $28.2 $31.0 $696.3 $790.4

Treatment ......................................................................... 665.9 756.5 27.2 29.6 693.1 786.0

Monitoring/Administrative ................................................. 2.2 3.0 1.0 1.4 3.2 4.4

State Costs ...................................................................... 1.4 1.6 0.1 0.2 1.5 1.7

Total 1 ........................................................................ 669.4 761.0 28.3 31.1 697.8 792.1

MCL = 5 μg/L

System Costs ................................................................... 396.4 451.1 17.3 18.9 413.5 470.2

Treatment ......................................................................... 394.4 448.3 16.3 17.6 410.6 466.1

Monitoring/Administrative ................................................. 2.0 2.8 1.0 1.3 2.9 4.1

State Costs ...................................................................... 1.1 1.3 0.1 0.2 1.2 1.4

Total 1 ........................................................................ 397.5 452.5 17.3 19.1 414.8 471.7

Final MCL = 10 μg/L

System Costs ................................................................... 171.4 195.5 7.9 8.9 179.4 204.4

Treatment ......................................................................... 169.6 193.0 7.0 7.6 176.7 200.6

Monitoring/Administrative ................................................. 1.8 2.5 0.9 1.3 2.7 3.8

State Costs ...................................................................... 0.9 1.0 0.1 0.2 1.0 1.2

Total 1 ........................................................................ 172.3 196.6 8.1 9.1 180.4 205.6

MCL = 20 μg/L

System Costs ................................................................... 62.4 71.4 3.5 4.1 65.9 75.5

Treatment ......................................................................... 60.7 69.0 2.6 2.8 63.3 71.8

Monitoring/Administrative ................................................. 1.7 2.4 0.9 1.3 2.6 3.7

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7011

TABLE III.E–1.—TOTAL ANNUAL NATIONAL SYSTEM AND STATE COMPLIANCE COSTS—Continued

[$ millions, 1999]

Discount rate

CWS NTNCWS Total

3 percent 7 percent 3 percent 7 percent 3 percent 7 percent

State Costs ...................................................................... 0.7 0.8 0.1 0.2 0.9 1.0

Total 1 ........................................................................ 63.2 72.3 3.6 4.2 66.8 76.5

1Total may not match detail due to rounding.

b. Household costs. Table III.E–2

shows mean annual costs per household

for those households that are served by

systems that may need to treat under

today’s rule. As discussed in Table

III.C–6 of today’s preamble and Table 8–

2 of the Economic Analysis, of the

approximately 74,000 systems that are

covered by today’s rule, EPA estimates

that only about 3,433 of these systems

will require treatment. Table III.E–2

refers only to the households served by

systems expected to need treatment. The

average household cost increase

resulting from today’s rule is $31.85.

However, due to economies of scale,

costs per household are higher in the

smaller size categories, and lower in the

larger size categories. For today’s rule

(10 μg/L), costs are expected to be

$326.82 per household for systems

serving <100 people, and $162.50 per

household for systems serving 101–500

people. Costs per households in systems

larger than those are substantially lower:

From $70.72 to $0.86 per household. As

shown in Table III.E–2, the costs per

household do not vary dramatically

across MCL options although Table

III.E–1 shows that total national costs

are significantly different. This

divergence is attributable to the total

number of households affected by each

MCL level and not the cost of treatment.

For example, approximately eleven

million households would be affected

by an MCL of 3 μg/L compared to

approximately three million affected by

the today’s final rule MCL of 10 μg/L.

In addition, the household costs change

relatively little among MCL options

because while each progressively lower

MCL option brings in a larger number of

systems subject to the rule, the majority

of those systems generally need only

minimal removal of arsenic. This fact

offsets, to an extent, the increased costs

as a result of more systems covered at

lower MCL options. A more detailed

discussion of household costs can be

found in Chapter 6 of the ‘‘Arsenic

Economic Analysis’’ document (EPA,

2000o).

TABLE III.E–2.—MEAN ANNUAL COSTS PER HOUSEHOLD

[in 1999 dollars] 1

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

<100 ................................................................................................................................. $317.00 $318.26 $326.82 $351.15

101–500 ........................................................................................................................... 166.91 164.02 162.50 166.72

501–1,000 ........................................................................................................................ 74.81 73.11 70.72 68.24

1,001–3.300 ..................................................................................................................... 63.76 61.94 58.24 54.36

3.301–10,000 ................................................................................................................... 42.84 40.18 37.71 34.63

10,001–50,000 ................................................................................................................. 38.40 36.07 32.37 29.05

50,001–100,000 ............................................................................................................... 31.63 29.45 24.81 22.63

100,001–1,000,000 .......................................................................................................... 25.29 23.34 20.52 19.26

>1,000,000 ....................................................................................................................... 7.41 2.79 0.86 0.15

All categories ................................................................................................................... 41.34 36.95 31.85 23.95

1Only households served by those systems expected to install treatment.

2. Summary of Benefits Analysis

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, and neurological,

endocrine effects. A complete list of the

arsenic-related health effects reported in

humans is discussed in section III. D of

this preamble. Current research on

arsenic exposure has only been able to

provide enough information to conduct

a quantitative assessment of bladder and

lung cancers. The other health effects

and possible non-health benefits remain

unquantified in this analysis but are

discussed qualitatively. It is important

to note that if the Agency were able to

quantify additional arsenic-related

health effects and non-health effects, the

quantified benefits estimates may be

significantly higher than the estimates

presented in this analysis. In addition,

the SDWA amendments of 1996 require

that EPA fully consider both

quantifiable and non-quantifiable

benefits that result from drinking water

regulations and has done this for today’s

arsenic rule.

a. Primary analysis. Quantifiable

benefits. Although arsenic in drinking

water has been associated with

numerous health effects (see section

III.D), the quantified benefits that result

from today’s rule are associated only

with reductions in arsenic-related

bladder and lung cancers. A complete

discussion of risk assessment

methodology and assumptions can be

found in Chapter 5 of the ‘‘Arsenic

Economic Analysis’’ document (EPA,

2000o).

The quantified benefits for today’s

rule for both CWSs and NTNCWSs

range from $140 million to $198 million

and consider both lower- and upperbound risk levels. Specifically, the

benefits to the CWSs are approximately

$138.2 million to $193.2 million and

$1.4 million to $4.5 million for

NTNCWSs. Table III.E–3 shows the

complete range of quantified benefits for

the other MCL levels considered by the

Agency. Section III.D.2. of this preamble

explains the derivation of the upperand lower-bound estimates

7012 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

In order to monetize the benefit from

the bladder and lung cancers cases

avoided, the Agency used two different

values. First, a value of statistical life

(VSL) estimate was applied to those

cancer cases that result in a mortality.

EPA assumed a 26% mortality rate for

bladder cancer and an 88% mortality

rate for lung cancer (EPA, 1999j; EPA,

1998n). The current VSL value used by

the Agency is $6.1 million, in 1999

dollars. This value of $6.1 million does

not reflect any adjustments to account

for national real income growth that

occurred subsequent to the completion

of the wage-risk studies on which EPA’s

VSL estimate is derived. Were the

Agency to adjust the VSL to account for

this growth in real income, the VSL

would be approximately $6.77 million

(assuming a 1.0 income elasticity).

Second, a willingness-to-pay value

(WTP) is used to monetize the cancer

cases that do not result in a mortality.

The WTP value for avoiding a non-fatal

cancer is not currently available;

therefore, the Agency used a WTP

estimate to reduce a case of chronic

bronchitis as a proxy. The use of this

value may understate the true benefit if

the WTP to avoid a nonfatal cancer is

greater than the WTP to avoid a case of

chronic bronchitis. The mean value of

this WTP estimate is $607,000 (in 1999

dollars). A complete discussion of the

VSL and WTP values and how they are

calculated can be found in Chapter 5 for

the ‘‘Arsenic Economic Analysis’’

document (EPA, 2000o).

—Non-quantifiable benefits. There are a

number of important non-quantified

benefits that EPA considered in its

analysis. Chief among these are

certain health impacts known to be

caused by arsenic, though, while they

may be substantial, the extent to

which these impacts occur at levels

below 50 μg/L is unknown. These

additional health effects include

cancers, other than bladder and lung

cancers, as well as non-cancer health

effects. In addition, EPA has

identified non-health benefits that

may result from today’s rule, which

are discussed next.

EPA was not able to quantify many of

the health effects potentially associated

with arsenic due to data limitations.

These health effects include other

cancers such as skin and prostate cancer

and non-cancer endpoints such as

cardiovascular, pulmonary, and

neurological impacts. These health

effects and the relevant studies linking

these health effects to arsenic in

drinking water are discussed in section

III.D. of today’s rule. For example, 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.

Other potential benefits not quantified

or monetized in today’s rule include

reduced uncertainty about becoming ill

from consumption of arsenic in drinking

water and the ability for some treatment

technologies to eliminate multiple

contaminants. The reduced uncertainty

concept depends on several factors

including consumer’s degree of risk

aversion, their perceptions about the

drinking water quality (degree to which

they will be affected by the regulatory

action), and the expected probability

and severity of human heath effects

associated with arsenic contamination

of drinking water. Another nonquantified benefit is the effect on those

systems that install treatment

technologies that can address multiple

contaminants. For example, membrane

systems, such as reverse osmosis, can be

used for arsenic removal but can also

remove many other contaminants that

EPA is in the process of regulating or

considering regulating. Therefore, by

installing a reverse osmosis system, a

system may not have to make any

additional changes to comply with these

future regulations.

TABLE III.E–3.—ESTIMATED BENEFITS FROM REDUCING ARSENIC IN DRINKING WATER

[$ millions 1999]

Arsenic level

(μg/L)

Total quantified

health benefits 1 Potential non-quantified health benefits includes reductions in:

3 ........................ $213.8–$490.9 • Skin Cancer.

5 ........................ $191.1–$355.6 • Kidney Cancer.

10 ...................... $139.6–$197.7 • Cancer of the Nasal Passages.

20 ...................... $66.2–$75.3 • Liver Cancer.

• Prostate Cancer.

• Cardiovascular Effects.

• Pulmonary Effects.

• Immunological Effects.

• Neurological Effects.

• Endocrine Effects.

1Benefits from reduction in bladder and lung cancer. The range represents both a lower and upper bound risk as discussed in section III. D. of

this preamble.

b. Sensitivity analysis on benefits

valuation. For the final rulemaking

analysis, some commenters have argued

that the Agency should consider an

assumed time lag or latency period in its

benefits calculations. The term

‘‘latency’’ can be used in different ways,

depending on the context. For example,

health scientists tend to define latency

as the period beginning with the initial

exposure to the carcinogen and ending

when the cancer is initially manifested

(or diagnosed), while others consider

latency as the period between

manifestation of the cancer and death.

Latency, in this case, refers to the

difference between the time of initial

exposure to environmental carcinogens

and the actual mortality. Use of such an

approach might reduce significantly the

present value of health risk reduction

benefits estimates.

In the proposed arsenic rule, the

Agency included qualitative language

on the latency issue, including

descriptions of other adjustments which

may influence the estimate of economic

benefits associated with avoided cancer

fatalities. The Agency also agreed to ask

the SAB to conduct a review of the

benefits’ transfer issues and possible

adjustment factors associated with

economic valuation of mortality risks. A

summary of the SAB’s

recommendations is shown in the

following section.

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7013

c. SAB recommendations. EPA

brought this issue before the

Environmental Economics Advisory

Committee (EEAC) of EPA’s SAB in a

meeting held on February 25, 2000 in

Washington, DC. The SAB submitted a

final report on its findings and

recommendations to EPA on July 27,

2000. The Panel’s report made a number

of recommendations on the adjustment

factors and benefit-cost analysis in

general. A copy of the final SAB report

(EPA, 2000j) is in the record for this

rulemaking.

The SAB Panel noted that benefit-cost

analysis, as described in the Agency’s

Guidelines for Preparing Economic

Analysis (EPA, 2000k), is not the only

analytical tool nor is efficiency the only

appropriate criterion for social decision

making. The SAB Panel also stated that

it is important to carry out such

analyses in an unbiased manner with as

much precision as possible. In its report,

the SAB recommended that the Agency

continue to use a wage-risk-based VSL

as its primary estimate; any appropriate

adjustments that are made for timing

(e.g., latency) and income growth

should be part of the Agency’s main

analysis while any other proposed

adjustments should be accounted for in

sensitivity analyses to show how results

would change if the VSL were adjusted

for some of the major differences in the

characteristics of the risk and of the

affected populations. The SAB

recommended including only

adjustments for latency and income

growth in the main analysis because it

did not believe any of the other

proposed adjustments were adequately

supported in the literature at the present

time. Specifically, the SAB report

recommended that (1) Health benefits

brought about by current policy

initiatives (i.e., after a latency period)

should be discounted to present value

using the same rate that is used to

discount other future benefits and costs

in the primary analysis; and any other

proposed adjustments should be

accounted for in a sensitivity analysis

including adjustments to the VSL for a

‘‘cancer premium,’’ voluntariness and

controllability, altruism, risk aversion,

and ages of the affected population. No

adjustment should be made to the VSL

to reflect health status of persons whose

cancer risks are reduced. (2) Estimates

of VSLs accruing in future years should

be adjusted in the primary analysis to

reflect anticipated income growth, using

a range of income elasticities.

After considering the SAB’s

recommendations, EPA has developed a

sensitivity analysis of the latency

structure and associated benefits for the

arsenic rule, as described in the next

section and in the Economic Analysis

for the final rule. This analysis consists

of health risk reduction benefits that

reflect adjustments for discounting,

incorporation of a range of latency

period assumptions, adjustments for

growth in income, and incorporation of

other factors such as voluntariness and

controllability. Although the SAB

recommended accounting for latency in

a primary benefits analysis, the Agency

believes that, in the absence of any

sound scientific evidence on the

duration of particular latency periods

for arsenic related cancers, discounted

benefits estimates for arsenic are more

appropriately accounted for in a

sensitivity analysis. Sensitivity analyses

are generally reserved for examining the

effects of accounting for highly

uncertain factors, such as the estimation

of latency periods, on health risk

reduction benefits estimates.

Defining a latency period is highly

uncertain because the length of the

latency period is often poorly

understood by health scientists. In some

cases, information on the progression of

a cancer is based on animal studies, and

extrapolation to humans is complex and

uncertain. Even when human studies

are available, the dose considered may

differ significantly from the dose

generally associated with drinking water

contaminants (e.g., involve a high level

of exposure over a short time period,

rather than a long term, low level of

exposure). The magnitude of the dose,

may in turn, affect the resulting latency

period. Information on latency may be

unavailable in many cases or, if

available, may be highly uncertain and

vary significantly across individuals.

The Agency recognizes, however, that

despite significant uncertainty in the

latency period associated with arsenic

exposure through drinking water, it is

unlikely that all cancer reduction

benefits would be realized immediately

upon exposure reduction. To the extent

that there are delays due to latency in

the realization of these benefits,

monetized cancer reduction benefits

would be discounted; although, as

discussed above, this may be offset by

other adjustments.

d. Analytical approach. For the

latency sensitivity analysis, the health

benefits have been broken into separate

treatments of morbidity and mortality.

The mortality component of the total

benefits is examined in this analysis

because a cancer latency period (i.e., the

time period between initial exposure to

environmental carcinogens and the

actual fatality) impacts arsenic-related

fatalities to a greater extent than arsenicrelated morbidity. For purposes of this

analysis, the Agency examined the

impacts of various latency period

assumptions, adjustments for income

growth, and incorporation of other

adjustments such as a voluntariness and

controllability, on bladder and lung

cancer fatalities associated with arsenic

in drinking water (EPA, 2000k).

Because the latency period for arsenic

related bladder and lung cancers is

unknown, EPA has assumed a range of

latency periods from 5 to 20 years.

While both lung and bladder cancer

have relatively long, average latencies,

the lower end of the latency period is

substantially less. As can be seen by

inspection of the Surveillance,

Epidemiology, and End Results (SEER)

data of the National Cancer Institute,

significant incidence of both cancers

occurs in individuals in the 15–19 year

old age groups (NCI, 2000). This

strongly indicates a short latency period

for whatever the cause of the cancer

may have been.

Moreover, the mode of action for

arsenic is suspected to be one that

operates at a late stage of the cancer

process that may advance the

expression of cancers initiated by other

causes (sometimes referred to as

‘‘promoting out’’ the cancerous effect).

Therapeutic treatment with the drug

cyclophosphamide, which causes cell

toxicity, has been seen to induce

bladder cancer in as little as 7 months

to 15 years in affected patients. This was

of course a high dose treatment, but the

example serves to illustrate the ability of

an agent to advance the development of

cancer.

For these reasons, we believe latency

periods of 5, 10, and 20 years serve as

reasonable approximations, in the

absence of definitive data on arsenicinduced cancers, of the latency periods

for the sensitivity analysis.

Table III.E–4 shows the sensitivity of

the primary analysis VSL estimate ($6.1

million, 1999 dollars) to changes in

latency period assumptions and also

with the incorporation of an adjustment

to reflect changes in WTP based on real

income growth and other adjustment

factors. As is shown in Table III.E–4, the

adjusted VSL is greater than the primary

VSL ($6.77 million versus $6.1 million)

at an income elasticity of 1.0, with

adjustments for income growth only.

Assuming a 3% discount rate, the

lowest adjusted VSL value ($3.44

million) is yielded over a 20-year

latency period that includes discounting

and income growth only (income

elasticity = 0.22). Assuming a 7%

discount rate, the highest adjusted VSL

is also $6.77 million (adjusted for

income growth only (income elasticity =

1.0)). The lowest adjusted VSL is $1.61

million (discounted over 20 years).

7014 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

TABLE III.E–4.— SENSITIVITY OF THE PRIMARY VSL ESTIMATE TO CHANGES IN LATENCY PERIOD ASSUMPTIONS, INCOME

GROWTH, AND OTHER ADJUSTMENTS

[$ millions, 1999]

Adjustment factor

Latency period (Years)

5 10 20

3% Discount Rate

Primary Analysis (No VSL Adjustment) ......................................................................................................... 6.1 6.1 6.1

Adjusted for Income Growth: 1

elasticity = 0.22 ....................................................................................................................................... 6.22 6.22 6.22

elasticity = 1.0 ......................................................................................................................................... 6.77 6.77 6.77

Adjusted for Income Growth 1 and Discounting:

elasticity = 0.22 ....................................................................................................................................... 5.37 4.63 3.44

elasticity = 1.0 ......................................................................................................................................... 5.84 5.04 3.75

Adjusted for Income Growth,1 Discounting, and 7% Increase for Voluntariness and Controllability;

elasticity = 0.22 ....................................................................................................................................... 5.74 4.95 3.69

elasticity = 1.0 ......................................................................................................................................... 6.25 5.39 4.01

Break-Even for Other Characteristics (as a percentage of the primary VSL estimate);

elasticity = 0.22 ....................................................................................................................................... 6 percent 19 percent 40 percent

elasticity = 1.0 ......................................................................................................................................... ¥2 percent12 percent 34 percent

7% Discount Rate

Primary Analysis (No VSL Adjustment) ......................................................................................................... 6.1 6.1 6.1

Adjusted for Income Growth:1

elasticity = 0.22 ....................................................................................................................................... 6.22 6.22 6.22

elasticity = 1.0 ......................................................................................................................................... 6.77 6.77 6.77

Adjusted for Income Growth 1 and Discounting:

elasticity = 0.22 ....................................................................................................................................... 4.44 3.16 1.61

elasticity = 1.0 ......................................................................................................................................... 4.83 3.44 1.75

Adjusted for Income Growth, 1 Discounting, and 7% Increase for Voluntariness and Controllability:

elasticity = 0.22 ....................................................................................................................................... 4.75 3.38 1.72

elasticity = 1.0 ......................................................................................................................................... 5.17 3.68 1.87

Break-Even for Other Characteristics (as a percentage of the primary VSL estimate):

elasticity = 0.22 ....................................................................................................................................... 22 percent 45 percent 72 percent

elasticity = 1.0 ......................................................................................................................................... 15 percent 40 percent 69 percent

1This adjustment reflects the change in WTP based on real income growth from 1990 to 1999.

The first row of both the 3% and 7%

discount rate panels in Table III.E–4

shows the VSL used in the primary

analysis. Because this value has not

been adjusted for discounting over an

assumed and unknown latency period,

this value does not deviate from the

original $6.1 million used in the

primary benefits analysis. The second

and third rows of both the 3 and 7

percent panels show the adjustments to

the primary VSL to account for changes

in WTP for fatal risk reductions

associated with real income growth

from 1990 to 1999. As real income

grows, the WTP to avoid fatal risks is

also expected to increase at a rate

corresponding to the income elasticity

of demand, as discussed below. This

income growth, from the years 1990 to

1999, accounts for the differences in

incomes of the VSL study population

versus the population affected by the

arsenic rule. This does not include any

income adjustments over a latency

period because of methodological issues

that have not yet been resolved.

However, pending the resolution of

these issues, EPA may include an

adjustment for income growth over a

latency period in future analyses, as

recommended by the SAB.

The fourth and fifth rows of both the

3% and 7% panels illustrates the

impacts of adjusting the primary VSL

for discounting and WTP changes based

on real income growth over a range of

assumed latency periods. As is shown

in Table III.E–4, this value decreases

from $5.84 million assuming a five-year

latency period to $3.75 million

assuming a 20-year latency period (at a

3% discount rate and income elasticity

of 1.0). At a 7% discount rate, this value

decreases from $4.83 million to $1.75

million.

The sixth and seventh rows of the 3%

and 7% panels illustrate the effects of

incorporating a 7% increase for

voluntariness and controllability. The

7% adjustment is based on a study by

Cropper and Subramanian (1999) that

indicates individuals may place a

slightly higher Willingness to Pay

(WTP) on risks where exposure is

neither voluntary nor controllable by

the individual.

In adjusting for WTP changes based

on real income growth, EPA used a

range of income elasticities from the

economics literature. Income elasticity

is the % change in demand for a good

(in this case, WTP for fatal risk

reductions) for every 1% change in

income. For example, an income

elasticity of 1.0 implies that a 10 percent

higher income level results in a 10%

higher WTP for fatal risk reductions. In

a recent study (EPA, 2000l), EPA

reviewed the literature related to the

income elasticity of demand for the

prevention of fatal health impacts.

Based on data from cross-sectional

studies of wage premiums, a range of

elasticity estimates for serious health

impacts was developed, ranging from a

lower-end estimate of 0.22 to an upperend estimate of 1.0.

There are several other characteristics

that differ between the VSL estimates

used in the primary analysis and an

ideal estimate specific to the case of

cancer risks from arsenic. These might

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7015

include a cancer premium, differences

in risk aversion, altruism, age of the

individual affected, and a morbidity

component of the VSL mortality

estimate. Very little empirical

information is available on the impact

that these characteristics have on VSL

estimates so they are not accounted for

directly in this sensitivity analysis. A

more complete discussion of the other

characteristics identified by economists

as having a potential impact on

willingness to pay to reduce mortality

risks can be found in chapter seven of

the Agency’s ‘‘Guidelines for Preparing

Economic Analyses’’ (EPA 2000k),

which is available in the docket for this

final rulemaking.

However, it is possible to use a

different type of analysis to address the

question: what would the impact on

VSL of these additional characteristics

need to be to produce the $6.1 million

VSL used in the primary benefits

analysis? (See primary benefits analysis

in section III.E.2.a of today’s rule.) The

last two rows of the 3% and 7% panels

of Table III.E–4 attempt to answer this

question in percentage terms. For

example, at a 3% discount rate over a

10-year latency period, income elasticity

of 1.0, and a 7% adjustment for

controllability and voluntariness, a

factor of 12% (as shown in the bottom

row of the 3% panel of Table III.E–4)

indicates that if accounting for these

characteristics would increase VSL by

more than 12% then the primary

analysis will tend to understate the

value of risk reductions. If accounting

for these characteristics would not

increase VSL by at least 12%, then the

primary analysis may overstate benefits

(a negative % indicates that the primary

analysis understates benefits unless the

combined impact of these additional

characteristics actually reduces VSL

estimates).

Some researchers believe that the

value of some of these characteristics

will substantially add to the unadjusted

VSL (one study suggests that a cancer

premium alone may be worth an

additional 100% of primary VSL value

(Revesz, 1999)). Some researchers also

believe that some of these

characteristics have a negative effect on

VSL, suggesting that some of these

factors offset one another. Until we

know more about these various factors

we cannot explicitly make adjustments

to existing VSL estimates. The SAB

noted in its report that these

characteristics require more empirical

research prior to incorporation into the

Agency’s primary benefits analysis, but

could be explored as part of a sensitivity

analysis.

e. Results. Table III.E–5 illustrates the

impacts of changes in VSL adjustment

factor assumptions on the estimated

benefits for the range of fatal bladder

and lung cancer cases avoided in the

final arsenic rule, assuming a 3%

discount rate. The results of this

analysis at a 7% discount rate are given

in Table III.E–6. These results were

calculated by applying the adjusted VSL

from Table III.E–4 to the lower- and

upper-bound estimates of fatal bladder

and lung cancer cases avoided as shown

in Table III.E–3 in section III.D.2 of

today’s rule. For purposes of this

sensitivity analysis, EPA presented

combined bladder and lung cancer cases

avoided in Tables III.E–5 and III.E–6.

Health risk reduction benefits

attributable to reduced arsenic levels in

both CWSs and NTNCWSs are

presented in these tables as well.

It is important to note that the

monetized benefits estimates shown in

this section reflect quantifiable benefits

only. As shown in section III.E.2.a, there

may be a number of nonquantifiable

benefits associated with regulating

arsenic in drinking water. Were EPA

able to quantify some of the currently

nonquantifiable health effects and other

benefits associated with arsenic

regulation, monetized benefits estimates

would be higher than what is shown in

the table. A more complete discussion

of how risks from arsenic in drinking

water and the corresponding health

benefits were calculated is provided in

the ‘‘Arsenic Economic Analysis’’ (EPA,

2000o), which is available in the docket

for this final rulemaking.

TABLE III.E–5.—SENSITIVITY OF COMBINED ANNUAL BLADDER AND LUNG CANCER MORTALITY BENEFITS ESTIMATES TO

CHANGES IN VSL ADJUSTMENT FACTOR ASSUMPTIONS

[$ millions, 1999, 3% discount rate] 1

Arsenic Level (μg/L) 3 5 10 20

5-Year Latency Period Assumption

Primary Analysis (No VSL Adjustment) ........................................................................... 199–452 176–328 130–182 62–69

Adjusted for Income Growth 2

E = 0.22 .................................................................................................................... 203–461 181–334 133–186 63–70

E = 1.0 ...................................................................................................................... 221–502 197–364 144–202 69–77

Adjusted for Income Growth2 and Discounting:

E = 0.22 .................................................................................................................... 175–398 156–288 114–160 55–61

E = 1.0 ...................................................................................................................... 190–433 170–314 124–174 60–66

Adjusted for Income Growth,2 Discounting, and 7% Increase for Voluntariness and

Controllability:

E = 0.22 .................................................................................................................... 187–425 167–308 122–171 59–65

E = 1.0 ...................................................................................................................... 204–463 182–336 133–186 64–71

10-Year Latency Period Assumption

Primary Analysis (No VSL Adjustment) ........................................................................... 199–452 176–328 130–182 62–69

Adjusted for Income Growth: 2

E = 0.22 .................................................................................................................... 203–461 181–334 133–186 63–70

E = 1.0 ...................................................................................................................... 221–502 197–364 144–202 69–77

Adjusted for Income Growth,2 and Discounting:

E = 0.22 .................................................................................................................... 151–343 135–249 99–138 47–52

E = 1.0 ...................................................................................................................... 164–373 147–271 107–150 51–57

Adjusted for Income Growth,2 Discounting, and 7% Increase for Voluntariness and

Controllability:

E = 0.22 .................................................................................................................... 161–367 144–266 105–148 50–56

E = 1.0 ...................................................................................................................... 176–399 157–289 115–161 55–61

7016 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

TABLE III.E–5.—SENSITIVITY OF COMBINED ANNUAL BLADDER AND LUNG CANCER MORTALITY BENEFITS ESTIMATES TO

CHANGES IN VSL ADJUSTMENT FACTOR ASSUMPTIONS—Continued

[$ millions, 1999, 3% discount rate] 1

Arsenic Level (μg/L) 3 5 10 20

20-Year Latency Period Assumption

Primary Analysis (No VSL Adjustment) ........................................................................... 199–452 176–328 130–182 62–69

Adjusted for Income Growth: 2

E = 0.22 .................................................................................................................... 203–461 181–334 133–186 63–70

E = 1.0 ...................................................................................................................... 221–502 197–364 144–202 69–77

Adjusted for Income Growth 2 and Discounting:

E = 0.22 .................................................................................................................... 112–255 100–185 73–103 35–39

E = 1.0 ...................................................................................................................... 122–278 109–201 80–112 38–42

Adjusted for Income Growth,2 Discounting, and 7% Increase for Voluntariness and

Controllability:

E = 0.22 .................................................................................................................... 120–273 107–198 79–110 38–42

E = 1.0 ...................................................................................................................... 131–297 117–215 85–119 41–45

1The lower- and upper-bound benefits estimates correspond to the lower- and upper-bound risk estimates and cancer cases avoided as

shown in section III.D.2 of this preamble. 2This adjustment reflects the change in WTP based on real income growth from 1990 to 1999. E = income elasticity.

TABLE III.E–6.—SENSITIVITY OF COMBINED ANNUAL BLADDER AND LUNG CANCER MORTALITY BENEFITS ESTIMATES TO

CHANGES IN VSL ADJUSTMENT FACTOR ASSUMPTIONS

[$ millions, 1999, 7% discount rate] 1

Arsenic Level (μg/L) 3 5 10 20

5-Year Latency Period Assumption

Primary Analysis (No VSL Adjustment) ........................................................................... 199–452 178–328 130–182 62–69

Adjusted for Income Growth: 2

E = 0.22 .................................................................................................................... 203–461 181–334 133–186 63–70

E = 1.0 ...................................................................................................................... 221–502 197–364 144–202 69–77

Adjusted for Income Growth,2 and Discounting:

E = 0.22 .................................................................................................................... 145–329 129–238 95–132 45–50

E = 1.0 ...................................................................................................................... 157–358 141–259 103–144 50–55

Adjusted for Income Growth,2 Discounting, and 7% Increase for Voluntariness and

Controllability:

E = 0.22 .................................................................................................................... 155–352 138–255 102–142 49–54

E = 1.0 ...................................................................................................................... 168–383 150–278 110–154 53–58

10-Year Latency Period Assumption

Primary Analysis (No VSL Adjustment) ........................................................................... 199–452 178–328 130–182 62–69

Adjusted for Income Growth: 2

E = 0.22 .................................................................................................................... 203–461 181–334 133–186 63–70

E = 1.0 ...................................................................................................................... 221–502 197–364 144–202 69–77

Adjusted for Income Growth 2 and Discounting:

E = 0.22 .................................................................................................................... 103–234 92–170 67–94 32–36

E = 1.0 ...................................................................................................................... 112–255 100–185 73–103 35–39

Adjusted for Income Growth,2 Discounting, and 7% Increase for Voluntariness and

Controllability:

E = 0.22 .................................................................................................................... 110–251 98–182 72–101 35–38

E = 1.0 ...................................................................................................................... 120–273 107–198 78–110 38–42

20-Year Latency Period Assumption

Primary Analysis (No VSL Adjustment) ........................................................................... 199–452 178–328 130–182 62–69

Adjusted for Income Growth: 2

E = 0.22 .................................................................................................................... 203–461 181–334 133–186 63–70

E = 1.0 ...................................................................................................................... 221–502 197–364 144–202 69–77

Adjusted for Income Growth 2 and Discounting:

E = 0.22 .................................................................................................................... 53–119 47–86 34–48 16–18

E = 1.0 ...................................................................................................................... 57–130 51–94 37–52 18–20

Adjusted for Income Growth,2 Discounting, and 7% Increase for Voluntariness and

Controllability:

E = 0.22 .................................................................................................................... 56–127 50–92 37–51 18–20

E = 1.0 ...................................................................................................................... 61–139 54–100 40–56 19–21

1The lower- and upper-bound benefits estimates correspond to the lower- and upper-bound risk estimates and cancer cases avoided as

shown in section III.D.2 of this preamble. 2This adjustment reflects the change in WTP based on real income growth from 1990 to 1999. E = income elasticity.

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7017

As shown in Tables III.E–5 and III.E–

6, the highest range of adjusted benefits

estimates at the 10 μg/L MCL ($144–

$202 million) are yielded when benefits

are adjusted for changes in WTP based

on real income growth only with an

income elasticity of 1.0. The lowest

adjusted benefits estimates at the 10 μg/

L MCL ($73–$103 million at 3%, $34–

$48 million at 7%) are yielded under

the assumption of a 20-year latency

period that includes adjustments for

discounting and WTP changes based on

real income growth (income elasticity =

0.22). These results indicate the high

degree of sensitivity of benefits

estimates to different assumptions of a

latency period, discount rate, and

income elasticity and also the inclusion

of adjustments for income growth and

voluntariness and controllability.

3. Comparison of Costs and Benefits

This section presents a comparison of

quantifiable total national costs and

benefits for each of the arsenic

regulatory options considered. Three

separate analyses are considered,

including a direct comparison of

aggregate national costs and benefits, a

summary of benefit-cost ratios and net

benefits, and the results of a costeffectiveness analysis of each regulatory

option.

a. Total national costs and benefits.

Table III.E–7 shows the annual costs

and benefits associated with the 10 μg/

L MCL and also with three other arsenic

levels considered in the proposed rule.

Both costs and benefits increase as

arsenic levels decrease. Costs increase

over decreasing arsenic levels because

of the increasing number of systems that

must treat to lower arsenic levels.

Benefits estimates increase as arsenic

levels decrease due to the greater

number of both fatal and non-fatal

cancer cases avoided at lower arsenic

levels. Additionally, other potential

non-quantifiable health benefits are

summarized in Table III.E–7.

TABLE III.E–7 ESTIMATED ANNUAL COSTS AND BENEFITS FROM REDUCING ARSENIC IN DRINKING WATER

[1999, $ millions]

Arsenic

level

(μg/L)

Total national

costs to CWSs

and NTNCSs 1

Total bladder

cancer health

benefits 2

Total lung cancer health

benefits 2

Total combined cancer

health benefits 2

Potential nonquantifiable health benefits

3 ........... 697.8–792.1 58.2–156.4 155.6–334.5 213.8–490.9 Skin Cancer; Kidney Cancer; Cancer of the Nasal Passages;

Liver Cancer; Prostate Cancer; Cardiovascular Effects; Pulmonary Effects; Immunological Effects; Neurological Effects;

Endocrine Effects.

5 ........... 414.8–471.7 52.0–113.3 139.1–242.3 191.1–355.6

10 ......... 180.4–205.6 38.0–63.0 101.6–134.7 139.6–197.7

20 ......... 66.8–76.5 20.1–21.5 46.1–53.8 66.2–75.3

1 Costs include treatment, monitoring, O&M, and administrative costs to CWSs and NTNCWSs 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. 2The lower- and upper-bound bladder, lung, and combined cancer benefits estimates correspond to the lower- and upper-bound risk estimates

and cancer cases avoided as shown in section III.D.2 of this preamble; these estimates include both mortality and morbidity.

b. National net benefits and benefitcost ratios. Table III.E–8 describes the

quantifiable net benefits and the benefitcost ratios under various regulatory

levels for both CWSs and NTNCWSs at

3% and 7% discount rates. The net

benefits and benefit-cost ratios do not

include any of the potential

nonquantifiable health benefits that are

listed in the previous table. As shown

in Table III.E–8, under both the lowerand upper-bound estimates of avoided

lung and bladder cancer cases, the net

benefits decrease as the arsenic rule

MCL options become increasingly more

stringent. Similarly, the benefit-cost

ratios decrease with each more stringent

MCL option. Costs outweigh the

quantified benefits for the lower-bound

benefits estimates under all four MCL

options. Benefit-cost ratios are equal to

or greater than 1.0 for the upper-bound

benefits estimates (at both 3% and 7%

discount rates) for arsenic levels of 10

μg/L and 20 μg/L.

TABLE III.E—8. SUMMARY OF NATIONAL ANNUAL NET BENEFITS AND BENEFIT-COST RATIOS, COMBINED BLADDER AND

LUNG CANCER CASES

[1999, $ millions]123

Arsenic level (μg/L)

3 5 10 20

3% Discount Rate

Lower Bound ......................................... Net Benefits .......................................... (484.0) (223.7) (40.8) (0.6)

B/C Ratio .............................................. 0.3 0.5 0.8 1.0

Upper Bound ......................................... Net Benefits .......................................... (206.8) (59.2) 17.3 8.5

B/C Ratio .............................................. 0.7 0.9 1.1 1.1

7% Discount Rate

Lower Bound ......................................... Net Benefits .......................................... (578.3) (280.6) (66.0) (10.3)

B/C Ratio .............................................. 0.3 0.4 0.7 0.9

Upper Bound ......................................... Net Benefits .......................................... (301.1) (116.1) (7.9) (1.2)

7018 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

TABLE III.E—8. SUMMARY OF NATIONAL ANNUAL NET BENEFITS AND BENEFIT-COST RATIOS, COMBINED BLADDER AND

LUNG CANCER CASES—Continued

[1999, $ millions]123

Arsenic level (μg/L)

3 5 10 20

B/C Ratio .............................................. 0.6 0.8 1.0 1.0

1 Costs include treatment, monitoring, O&M, and administrative costs to CWSs and NTNCWSs 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. 2The lower- and upper-bound bladder, lung, and combined cancer benefits estimates correspond to the lower- and upper-bound risk estimates

and cancer cases avoided as shown in section III.D.2 of this preamble; unquantified benefits are not included. 3 Numbers in parentheses indicate negative numbers.

c. Incremental costs and benefits.

Incremental costs and benefits are those

that are incurred or realized in reducing

arsenic exposures from one level to the

next more stringent level (e.g., from 20

μg/L to 10 μg/L). Estimates of

incremental costs are useful in

developing estimates of the costeffectiveness of successively more

stringent requirements.

Table III.E–9 shows the incremental

total national risk reduction, arsenic

mitigation costs, and monetized health

benefits for the various arsenic levels

valued using discount rates of three and

seven percent.

TABLE III.E–9—ESTIMATES OF THE ANNUAL INCREMENTAL RISK REDUCTION, COSTS, AND BENEFITS OF REDUCING

ARSENIC IN DRINKING WATER

[$ millions, 1999]

Benefit-cost element

Arsenic level (μg/L)

20 10 5 3

Incremental Risk Reduction:

Fatal Cancers Avoided per Year 1 ............................................................................ 10.2–11.3 11.1–18.5 7.8–23.9 3.5–20.4

Incremental Risk Reduction:

Non-Fatal Cancers Avoided per Year 1 .................................................................... 8.5–8.8 7.6–17.1 5.9–20.6 2.6–17.7

Annual Incremental Monetized Benefits 2 ........................................................................ $66.2–$75.3 $73.4–

$122.4

$51.5–

$157.9

$22.7–

$135.4

Annual Incremental Costs (3%) 3 ..................................................................................... $66.8 $113.6 $234.4 $283.0

Annual Incremental Costs (7%) 3 ..................................................................................... $76.5 $129.1 $266.0 $320.5

1Total fatal and non-fatal cancer cases avoided are discussed in section III.D.2 of this preamble.

2The lower- and upper-bound combined cancer benefits estimates correspond to the lower- and upper-bound risk estimates and cancer cases

avoided as shown in section III.D.2 of this preamble. 3 Costs include treatment, monitoring, O&M, and administrative costs to CWSs and NTNCWSs and State costs for administration of water

programs.

d. Cost-per-case avoided. Cost-percase avoided is a commonly used

measure of the economic efficiency with

which regulatory options are meeting

the intended regulatory objectives.

Table III.E–10 shows the results of an

analysis in which the average national

cost of achieving each unit of reduction

in cases of bladder and lung cancer

avoided, was calculated. The average

annual cost per case avoided was

computed at each MCL option for both

3% and 7% discount rates.

As shown in Table III.E–10, the cost

per bladder and lung cancer case

avoided ranges from $4.8 million down

to $3.2 million at the 10 μg/L MCL,

assuming a 3% discount rate. At a 7%

discount rate, the cost per bladder and

lung cancer case avoided ranges from

$5.5 million down to $3.7 million at the

10 μg/L MCL. As expected, the cost per

bladder and lung cancer case avoided

decreases with increasing arsenic levels.

This is due to lower compliance costs at

higher levels for the standard.

TABLE III.E–10.—ANNUAL COST PER

CANCER CASE AVOIDED FOR THE

FINAL ARSENIC RULE—COMBINED

BLADDER AND LUNG CANCER CASES

$ millions, 1999]

Arsenic

level (μg/L)

Lower-bound

estimate 1

Upper-bound

estimate 1

3 % Discount Rate

3 ................ 12.2 5.0

5 ................ 8.1 4.1

10 .............. 4.8 3.2

20 .............. 3.5 3.4

7 % Discount Rate

3 ................ 13.8 5.7

5 ................ 9.2 4.7

10 .............. 5.5 3.7

TABLE III.E–10.—ANNUAL COST PER

CANCER CASE AVOIDED FOR THE

FINAL ARSENIC RULE—COMBINED

BLADDER AND LUNG CANCER

CASES—Continued

$ millions, 1999]

Arsenic

level (μg/L)

Lower-bound

estimate 1

Upper-bound

estimate 1

20 .............. 4.0 3.9

1The lower- and upper-bound cost per cancer case avoided corresponds to the range of

combined cancer benefits estimates as shown

in Table III.E–3.

4. Affordability

As noted previously, section

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

requires EPA, when promulgating a

national primary drinking water

regulation which establishes a

maximum contaminant level (MCL), to

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7019

list technology (considering source

water quality) that achieves compliance

with the MCL and is affordable for

systems in three specific population size

categories: 25–500, 501–3300, and

3301–10,000. If, for any given size

category/source water quality

combination, an affordable compliance

technology cannot be identified, section

1412(b)(15)(A) requires the Agency to

list a variance technology. Variance

technologies may not achieve full

compliance with the MCL but they must

achieve the maximum contaminant

reduction that is affordable considering

the size of the system and the quality of

the source water. In order for the

technology to be listed, EPA must

determine that this level of contaminant

reduction is protective of public health.

A determination of national level

affordability is concerned with

identifying, for each of the given size

categories, some central tendency or

typical circumstance relating to their

financial abilities. The metric EPA

selected for this purpose is the median

household income (MHI) for

communities of the specified sizes. The

household is thus the focus of the

national-level affordability analysis.

EPA considers treatment technology

costs affordable to the typical household

if they represent a percentage of MHI

that appears reasonable when compared

to other household expenditures. This

approach is based on the assumption

that the affordability to the median

household served by the CWS can serve

as an adequate proxy for the

affordability of technologies to the

system itself. The national-level

affordability criteria have two major

components: current annual water bills

(baseline) and the affordability

threshold (total % of MHI directed to

drinking water). Current annual water

bills were derived directly from the

1995 Community Water System Survey.

Based on 1995 conditions, 0.75–0.78%

of MHI is being directed to water bills

for systems serving fewer than 10,000

persons.

The fundamental, core question in

establishing national-level affordability

criteria is: what is the threshold beyond

which drinking water would no longer

be affordable for the typical household

in each system size category? Based

upon careful analysis EPA believes this

threshold to be 2.5% of MHI. In

establishing this threshold, the Agency

considered baseline household

expenditures (as documented in the

1995 Consumer Expenditure Survey,

Bureau of Labor Statistics) for piped

water relative to expenditure

benchmarks for other household goods,

including those perceived as substitutes

for piped water treated to higher

standards, such as bottled water and

point-of-use and point-of-entry devices.

Based on these considerations, EPA

concluded that current household water

expenditures are low enough, relative to

other expenditures, to support the cost

of additional risk reductions. The

detailed rationale for the selection of

2.5% MHI as the affordability threshold

is provided in the guidance document

entitled ‘‘Variance Technology Findings

for Contaminants Regulated Before

1996.’’ The difference between the

affordability threshold and current

water bills is the available expenditure

margin. This represents the dollar

amount by which the water bill of the

typical (median) household could

increase before exceeding the

affordability threshold of 2.5% of MHI.

By definition, the MHI is the income

value exactly in the middle of the

income distribution. The median is a

measure of central tendency; its purpose

is to help characterize the nature of a

distribution of values. In the case of

income, which tends not to be evenly

distributed, the median is a much better

indicator of central tendency than the

mean, or arithmetic average, that could

be significantly skewed by a few large

values. The Agency recognizes that

there will be half the households in

each size category with incomes above

the median, and half the households

with incomes below the median. The

objective of a national-level affordability

analysis is to look across all the

households in a given size category of

systems and determine what is

affordable to the typical, or ‘‘middle of

the road’’ household.

The Agency recognizes that baseline

costs change over time as water systems

comply with new regulations and

otherwise update and improve their

systems. To take account of this upward

movement in the baseline, the Agency

plans to adjust the baseline it employs

in its calculation in two ways. First,

actual changes in the baseline will be

measured approximately every 5 years

by the Community Water System

Survey. These changes will reflect not

only the increased costs resulting from

EPA drinking water rules, but also any

changes resulting from other factors that

could affect capital or operating and

maintenance costs. Second, to the extent

practical and appropriate during the

period between Community Water

System Surveys, the baseline will be

adjusted to reflect the cost of rules

promulgated during that period.

MHI also changes from year to year,

generally increasing in constant dollar

terms. For example, since 1995 MHI has

increased (in 1999$) by 9.6%. Thus, to

determine the available expenditure

margin (the difference between the

affordability threshold and the baseline)

for each successive rule, adjustments

would need to be made in both the

baseline and the MHI.

Given the narrow and specific

purpose for which the national-level

affordability criteria are used, the

Agency is not adjusting either the

baseline or the MHI for its analysis for

the final arsenic rule. As noted

previously, MHI has increased by 9.6%.

The rules, which have been

promulgated since the baseline was

developed, are the Interim Enhanced

Surface Water Treatment Rule, the Stage

1 Disinfectants and Disinfection

ByProducts Rule, the revised

Radionuclides Rule, the Consumer

Confidence Report Rule and the revised

Public Notification Rule. The Interim

Enhanced Surface Water Treatment Rule

applies only to systems serving greater

than 10,000 persons, so it has

essentially no impact on the baseline

costs for smaller systems. The Stage 1

Disinfectants and Disinfection

ByProducts Rule does apply to small

systems, and it has an impact on only

12% of the nearly 68,200 ground water

systems serving < 10,000 persons; and

on 70% of the nearly 5200 surface water

systems serving < 10,000 persons. The

revised Radionuclides Rule has limited

impact since it, for the most part,

reaffirmed long-standing MCLs. The

Consumer Confidence Rule and revised

Public Notification Rule result in no

capital expenditures and only very

modest administrative costs.

The Agency believes that, for

purposes of assessing national-level

affordability of the arsenic rule, the

unadjusted baseline and unadjusted

MHI are appropriate. Making

adjustments to these two factors would

not materially alter the outcome of the

analysis.

The distinction between nationallevel affordability criteria and

affordability assessments for individual

systems cannot be over-emphasized.

The national-level affordability criteria

serve only to guide EPA on the listing

of an affordable compliance technology

versus a variance technology for a given

system size/source water combination

for a given contaminant. In the case of

arsenic, EPA has determined that

nationally affordable technologies exist

for all system size categories and has

therefore not identified a variance

technology for any system size/source

water combination. This means that

EPA believes that the typical household

in each system size category can afford

the costs associated with the listed

compliance technologies. EPA

7020 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

recognizes that individual water

systems may serve a preponderance of

households with incomes well below

the median or may face unusually high

treatment costs due to some unusual

local circumstance.

SDWA provides a number of tools

that States can use to address

affordability concerns for these

individual water systems. Two of these

tools are financial assistance under the

Drinking Water State Revolving Fund

(DWSRF) and extended compliance

time-frames under an exemption. SDWA

allows States to provide special

assistance to water systems that the

State determines to be disadvantaged,

using State-developed affordability

criteria. This special assistance may

include forgiveness of principal, a

negative interest rate, an interest rate

lower than that charged to nondisadvantaged systems, and extended

repayment periods of up to 30 years. To

date, about half of the States have

implemented disadvantaged community

programs as part of their DWSRF.

Almost one quarter of all loans made

under the DWSRF have been made to

systems classified as disadvantaged by

the States.

In addition to special financial

assistance through the DWSRF, as

discussed previously, systems facing

affordability concerns may also be

eligible for extended time to achieve

compliance under the terms of a Stateissued exemption or may receive

assistance under the Rural Utilities

Service (RUS) program of the United

States Department of Agriculture (see

section I.L). Together with the

approximately $1 billion per year being

made available through the DWSRF, this

results in a total of about $1.78 billion

per year of Federal financial assistance

available for drinking water.

Decisions that a drinking water

system makes about how to allocate its

costs to users and how to design rates

can also have a significant effect on

affordability for low-income

households. A traditional declining

block rate structure would be regressive

and might result in the households with

the least income subsidizing excessive

water use by more affluent households.

Numerous alternative rate designs are

possible that are more progressive. Of

particular interest in addressing

affordability concerns is lifeline rates.

Lifeline rates are a rate structure

applicable to qualified residential

customers that includes a specified

block of water use priced below the

standard charge for the customer class.

Such rates are primarily designed to aid

the poor in obtaining some minimum

level of service at an affordable price.

The basic organizational or

institutional structure of the drinking

water system is another very important

factor that influences the affordability of

water service. The key issue here is the

extent to which a given organizational

or institutional structure is capable of

achieving economic and operational

efficiency. An especially important

element of this efficiency relates to the

degree to which a system seeks to work

together with other systems. Systems

that effectively work together, perhaps

by combining management, will realize

lower overall costs compared to the

same systems working independently.

F. What MCL Is EPA Promulgating and

What Is the Rationale for This Level?

1. Final MCL and Overview of Principal

Considerations

EPA is today promulgating a final

arsenic MCL of 10 μg/L. EPA’s selection

of this MCL is based on the SDWA

statutory requirements for establishing

an MCL and reflects the Agency’s

detailed evaluation and careful

consideration of thousands of pages of

comments. As part of this process, we

have evaluated new data and analysis

on occurrence, unit treatment costs,

small system impacts, treatment

technology availability, waste disposal

options, and uncertainties regarding

exposure and health effects data. Based

on this new information, the Agency has

revisited technical analyses,

calculations, and judgments underlying

the proposed MCL of 5 μg/L. As

discussed in section III.E. in this

preamble, the Agency has conducted a

thorough revaluation of costs and has

carefully considered substantial new

analysis on this subject submitted by

commenters. In addition, EPA has

completed a detailed reassessment of

the risks of arsenic in drinking water,

and has made significant adjustments to

provide a more quantitative evaluation

of major sources of uncertainty

discussed at proposal and emphasized

by commenters from a number of

different perspectives.

Today’s rule, with a final MCL of 10

μg/L, reflects the application of several

provisions under SDWA, the first of

which 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

SDWA amendments also require that

the Administrator determine whether or

not the quantifiable and nonquantifiable

benefits of an MCL justify the

quantifiable and nonquantifiable costs.

This determination is to be based on the

Health Risk Reduction and Cost

Analysis (HRRCA) required under

section 1412(b)(3)(C). The HRRCA must

include consideration of seven analyses:

(1) The quantifiable and

nonquantifiable benefits from treatment

to the new MCL;

(2) The quantifiable and non

quantifiable benefits resulting from

reductions of co-occurring

contaminants;

(3) The quantifiable and

nonquantifiable costs resulting directly

from the MCL;

(4) The incremental costs and

benefits at the new MCL and

alternatives considered;

(5) The health risks posed by the

contaminant, including risks to

vulnerable populations;

(6) Any increased risk resulting from

compliance, including risks associated

with co-occurring contaminants; and

(7) Any other relevant factor,

including the uncertainties in the

analyses and the degree and nature of

risk.

Finally, the 1996 SDWA amendments

provide 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)) based on the HRRCA

analysis. Today’s rule establishing an

MCL of 10 μg/L for arsenic is the second

time EPA has invoked this new

authority. (The first such time was in

the final rule for uranium, which was

published on December 7, 2000; EPA,

2000p.)

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 and the various comments offered

concerning these levels in response to

the proposed rule. EPA has determined

that a final MCL of 10 μg/L more

appropriately meets the relevant

statutory criteria referred to above,

particularly after considering the

following: Available information

relating to the various health effects

associated with arsenic; new analysis

regarding the projected risk to the

population of adverse health effects that

would remain after implementation; the

revised costs and benefits of the various

options; the incremental costs and

benefits; and the uncertainties in the

benefit-cost and risk analyses. A

summary of the results of the Agency’s

reanalysis of these various factors

follows.

2. Consideration of Health Risks

The fifth and seventh HRRCA

analyses focus on the health risks to be

addressed by a new MCL. Estimates of

risk levels to the population remaining

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7021

after the regulation is in place provide

a perspective on the level of public

health protection and associated

benefits. 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) requires EPA to set the MCL

at a level that ‘‘maximizes health risk

reduction benefits at a cost that is

justified by the benefits.’’ (EPA does not

believe the sixth HRRCA analysis,

consideration of increased risk likely to

result from compliance is a significant

factor in connection with selection of a

final MCL; rather, we believe that many

of the appropriate technologies for

reducing arsenic will reduce many other

co-occurring inorganic contaminants as

well thereby decreasing, rather than

increasing risk.)

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 a number of considerations,

including the bladder cancer risk

analysis developed by the National

Research Council (NRC) of the National

Academy of Sciences (NRC, 1999); the

NRC’s qualitative assessment of other

possible adverse health effects; the lung

cancer risk analysis developed by

Morales et al. (2000); and findings of

other relevant national and international

studies. This information included, but

was not limited to, findings from

epidemiological studies in South

America cited in the NRC report (NRC,

1999) and a study of a population

exposed to high levels of arsenic in

Millard County, Utah conducted by

Lewis, et al. (1999).

Among the factors EPA considered in

choosing the final MCL was Congress’

intent that EPA ‘‘reduce * * *

[scientific] uncertainty’’ in promulgating

the arsenic regulation reflected in

section 1412(b)(12) arsenic research

plan provisions and the legislative

history on the arsenic provision (S. Rep.

104–169, 104th Cong., 1st Sess. at 39–

40). The uncertainties in the analyses of

costs, benefits and risks are also a factor

required to be considered in the

HRRCA. All assessments of risk are

characterized by an amount of

uncertainty. Some of this uncertainty

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 several definable sources of

uncertainty that were taken into

account. These include, but are not

limited to, the following:

• Uncertainty about the exact

exposure of individuals in the study

population to arsenic in drinking water,

water used in cooking, and food;

• Uncertainties associated with

applying data from a population in rural

Taiwan to the heterogenous population

of the U.S. (including differences in

health status and diet between the

Taiwanese and the U.S. population);

and

• Uncertainties concerning precisely

how a chemical causes cancer in

humans (the mode of action) that affects

assessments of the extent and severity of

health effects at low doses.

Section III.D. of the preamble to

today’s final rule provides a detailed

explanation of how these uncertainties

associated with the risk analysis were

taken into account in developing a

revised estimate of the risk of arsenic in

drinking water. Based on comments and

available information, the Agency has

focused, in particular, on the first

uncertainty bullet, and made two

adjustments to its risk analysis to reduce

uncertainty and more accurately apply

data from the Taiwan study to the U.S.

population. EPA has revised its

quantified estimate of the risks of

arsenic in drinking water to adjust for

exposure to arsenic in both cooking

water and food in the Taiwanese study

and has also developed a risk range for

the combined effects of bladder and

lung cancer to reflect the scope of

uncertainty underlying these estimates.

Thus, one of the previously listed

uncertainties has specifically been taken

into account quantitatively, while others

continue to be considered in a

qualitative sense.

In EPA’s judgment, use of a risk range

more clearly supports a qualitative

consideration and recognition of the

uncertainties that are inherent in any

risk analysis that substantially relies

upon epidemiological information. EPA

believes that the health risk analysis

presented in section III.D. of today’s rule

comprises a plausible range of likely

risk associated with various

concentrations of arsenic in drinking

water. As just suggested, we do not

believe it is appropriate to select a

central or ‘‘best estimate’’ of the risk,

due to the uncertainties associated with

the underlying health effects studies

and the various plausible assumptions

used in considering these uncertainties

for our risk analysis. This revised

analysis of risks was used in

recalculating the benefits attributable to

reducing arsenic in drinking water from

its present levels. EPA also recognizes

that the latter two bulleted sources of

uncertainty may operate to reduce the

risk estimates if it were possible to

account for them quantitatively.

3. Comparison of Benefits and Costs

Under HRRCA analyses one and two,

the Agency must consider both

quantifiable and nonquantifiable health

risk reduction benefits. Benefits

considered in our analysis include those

about which quantitative information is

known and can be monetized as well as

those which are more qualitative in

nature (such as some of the non-cancer

health effects potentially associated

with arsenic) and which cannot

currently be monetized. Important

assumptions inherent in EPA’s revised

analysis of the benefits estimates

include the value of a statistical life and

willingness to pay to avoid illness.

These assumptions and various

adjustment factors considered for our

benefits analysis are explained in detail

in section III.E. of this preamble.

EPA considered the relationship of

the monetized benefits to the monetized

costs for each the regulatory levels it

considered. While strict equality of

monetized benefits and costs is not a

requirement under section

1412(b)(6)(A), this relationship is an

important consideration in the

regulatory development process. The

monetized costs and monetized benefits

of this final rule, and the methodologies

used to calculate them, are discussed in

detail in section III. E. of this preamble

and in the arsenic Economic Analysis.

EPA believes, however, that reliance

on only an arithmetic analysis of

whether monetized benefits outweigh

monetized costs is inconsistent with the

statute’s instruction to consider both

quantifiable and nonquantifiable costs

and benefits. The Agency therefore

examined and considered qualitative

and non-monetized benefits in

establishing the final MCL, as well as

other factors discussed previously.

These benefits are associated with

avoiding certain adverse health impacts

known to be caused by arsenic at higher

concentrations, which may also be

associated with low level

concentrations, and include skin and

prostate cancer as well as

cardiovascular, pulmonary, neurological

and other non-cancer effects. (These

health effects are discussed in Section

III.D. of this preamble.)

Other potential benefits not

monetized for today’s final rule include

customer peace of mind from knowing

drinking water has been treated for

arsenic and reduced treatment costs for

contaminants that may be co-treated

with arsenic. (For example, increased

use of coagulation and micro filtration

7022 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

by surface water systems will offer

benefits with respect to removal of

microbial contaminants and disinfection

byproducts.)

HRRCA analyses three and four

require EPA to consider the costs of

compliance with the rule and the

incremental costs and benefits. EPA has

also revised the cost of compliance

estimates associated with the various

possible regulatory levels considered for

today’s final rulemaking. The central

estimate of costs has risen modestly

since the proposed rule based on our

further analysis of the information and

data provided by commenters. However,

in response to comments, we have also

performed a sensitivity analysis that

addresses a number of variables in our

analysis and which indicates that the

costs of compliance could exceed our

central estimate by as much as 22%.

In comparing monetized costs and

benefits, we conducted several types of

analyses, including:

• Comparison of total national costs

and benefits (Table III.E–7);

• Analysis of incremental costs and

benefits (comparing one regulatory

option to another) (Table III.E–9);

• Estimates of net benefits (Table

III.E–8); and

• Examination of benefit-cost ratios

(Table III.E–8).

Detailed descriptions of our analyses

appear in section III.E. of this preamble

and in the Economic Analysis

supporting today’s rule. Our

consideration of these analyses in

support of the rationale for the final

MCL is discussed below.

4. Rationale for the Final MCL

The rationale for the final MCL

promulgated with today’s rule is based

on the HRRCA analyses outlined

previously and the statutory criteria for

setting an alternative (higher than

feasible) MCL under section 1412(b)(6).

These analyses include:

• A revised risk analysis of arsenic in

drinking water;

• A revised analysis of total costs;

• A revised analysis of total benefits;

• A comparison of costs and benefits

using various metrics at various MCL

options (including incremental costs

and benefits); and

• Other pertinent factors (including

uncertainties and the degree and nature

of risk).

In the proposed rule, EPA indicated a

preference for a standard at 5 μg/L, but

solicited comment on MCL options of 3

μg/L, 10 μg/L, and 20 μg/L, depending

upon how uncertainties were addressed

in the risk analysis as well in the

calculation of costs and benefits.

However, EPA also noted that, between

the time of proposal and promulgation

of the final rule, it would work to

resolve as much of this uncertainty as

possible. As described earlier, the

principal revised analyses conducted

since the rule was proposed and

considered in our selection of the final

MCL include: A revised analysis of the

uncertainties of the health effects that

has generated a revised risk range for

the various MCL options considered; a

revised range of benefits associated with

our current estimates of the risks; and a

revised analysis of costs, including

uncertainty and sensitivity analyses.

These revised analyses allow an

updated comparison of the costs and

benefits for the various regulatory

options considered.

a. General considerations. As

explained in section III.E. of today’s

preamble, both our benefits and cost

estimates involve ranges, rather than

point estimates, due to a variety of

factors. Thus, our consideration of costs

and benefits involved an examination

and comparison of these ranges. As can

be seen from Table III.E–7, both total

costs and benefits increase as one

examines progressively lower (i.e., more

stringent) regulatory options compared

to higher options. However, the benefits

and costs do not increase

proportionately across the range of

regulatory options as shown by a

comparison of net benefits (defined as

costs minus benefits). Progressively

more stringent regulatory options

become considerably more expensive,

from a cost standpoint, than the

corresponding increases in benefits, as

reflected in decreasing net benefits. (see

Table III.E–8.)

b. Relationship of MCL to the feasible

level (3 μg/L). The MCL must be set as

close as feasible to the MCLG, unless

EPA invokes its discretionary authority

under section 1412(b)(6) of SDWA to set

an alternative MCL, which must then be

set at a level that maximizes health risk

reduction benefits at a cost that is

justified by the benefits. As explained

earlier in this preamble, the MCLG is

zero and the feasible level is 3 μg/L. The

Agency believes that there are several

important considerations in examining

the feasible level. In comparing the

benefits and the costs at this level (see

Table III.E–7), we note that it has the

highest projected total national costs

(relative to the other MCL options

considered). In addition, while the

benefits are highest at this level relative

to the other MCL options, both the net

benefits and the benefit/cost disparity at

the feasible level are the least favorable

of the regulatory options considered.

For these reasons, we believe benefits of

the feasible level do not justify the costs.

Almost all commenters agreed with this

conclusion in the proposal.

c. Reanalysis of proposed MCL and

comparison to final MCL. Based on

substantial public comment, EPA has

reexamined the proposed MCL of 5 μg/

L. In comparing this level to 10 μg/L, we

note that both the net benefits and the

benefit-cost relationships are less

favorable for 5 μg/L as compared to 10

μg/L. Total national costs at 5 μg/L are

also approximately twice the costs of an

MCL of 10 μg/L. At 10 μg/L, EPA notes

that the lung and bladder cancer risks to

the exposed population after the rule’s

implementation are within the Agency’s

target risk range for drinking water

contaminants of 1 × 10 ¥6 to 1 × 10 ¥4

or below. EPA recognizes that there is

uncertainty in this quantification of

cancer risk (as well as other health

endpoints) and this risk estimate

includes a number of assumptions, as

discussed previously. EPA did not

directly rely on the risk range in

selecting the final MCL, since it is not

part of the section 1412(b)(6) criteria;

however, it is an important

consideration, because it has a direct

bearing on our estimates of the benefits

of the rule.

d. Consideration of higher MCL

options. EPA does not believe an MCL

less stringent 10 μg/L is warranted from

the standpoint of benefit-cost

comparison. While total national costs

associated with 20 μg/L are the lowest

of the regulatory options considered,

benefits are also the lowest of these

options. Both regulatory options of 10

μg/L and 20 μg/L have relatively

favorable benefit-cost relationships

relative to lower regulatory options but

are not significantly different from one

another based on this comparison

metric. However, the incremental,

upper-bound benefits at 10 μg/L are

more than twice those of 20 μg/L; and

10 μg/L is clearly the more protective

level. Thus, we do not believe that an

MCL of 20 μg/L would ‘‘maximize

health risk reduction benefits’’ as

required for an MCL established

pursuant to section 1412(b)(6).

e. Conclusion. 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 section

1412(b)(6) of SDWA. However, EPA

believes that, based on comparisons of

cost and benefits (using the various

benefit-cost comparison tools

discussed), the monetized benefits of a

regulatory level of 10 μg/L best justify

the costs. In addition, as discussed in

section III.D. and elsewhere in today’s

preamble, our further qualitative

consideration of the various sources of

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7023

uncertainty in our understanding of

arsenic since the proposal (e.g., such as

that surrounding the mode of action),

has led us to conclude that our estimate

of risk (for the risks we have quantified)

is most likely an upper bound of risks

and that the higher MCL of 10 μg/L is

appropriate. Finally, as discussed in

section III.E. of this preamble EPA

believes that there are a number of not

yet quantified adverse health effects and

potentially substantial non-monetized

benefits at 10 μg/L that increase the

overall benefits at this level.

In summary, based on our reanalysis

of costs, benefits, and health risk

reduction, and factoring in the

uncertainties in these analyses and the

degree and nature of risk, EPA believes

the final MCL of 10 μg/L represents the

level that best maximizes health risk

reduction benefits at a cost that is

justified by the benefits and that the

other regulatory options considered in

the proposed rule do not satisfy the

statutory requirements of section

1412(b)(6) of SDWA. We are therefore

exercising our discretionary authority

under the statute to establish an MCL at

a level higher than the feasible level and

setting that level at 10 μg/L.

IV. Rule Implementation

A. What Are the Requirements for

Primacy?

States must revise their programs to

adopt any part of today’s rule that 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. A State’s

request 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.’’ Today’s rule does not

require States to submit information in

§ 142.16(e) for primacy revisions

associated with the revised arsenic

MCL. The final rule notes that

§ 142.16(e) primacy revision

information will only be required for

new contaminants, not revisions of

existing regulated contaminants.

B. What Are the Special Primacy

Requirements?

Today’s rule adds special primacy

requirements in § 142.16(j) and

§ 142.16(k) to the State special primacy

requirement section. Section 142.16(j)

clarifies that for an existing regulated

contaminant such as arsenic, States 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 (NPDWRs) for

organic and inorganic contaminants (the

Phase II/V rules). Alternatively, the

State may inform the Agency in its

application of any changes to the

monitoring plans and waiver

procedures.

Section 142.16(k) requires States to

establish initial monitoring

requirements for new systems and new

sources. Many States already have

developed monitoring programs for new

systems and for systems that are using

new sources of water. To meet the

requirements of § 142.16(k), States that

have existing requirements may simply

explain to EPA in their primacy revision

package their monitoring schedule and

how the State can ensure that all new

systems and new sources will comply

with the existing MCLs and monitoring

requirements. Some States may wish to

explain that monitoring for new systems

is established on a case-by-case basis.

States should explain the factors that are

considered as case-by-case

determinations are made.

When a State develops or modifies an

initial monitoring program for new

systems and new sources, it should

ensure that the program reflects the

contaminant(s) of concern for that State,

known contaminant use, historical data,

and vulnerability. Because of varying

contaminant uses and sources, some

contaminants occur at higher levels in

some regions of the country than in

other regions. Additionally, the

concentrations of some contaminants

are known to show clear seasonal peaks,

while others remain constant

throughout the year. For example, some

States may be concerned with atrazine

and require multiple samples during a

specified vulnerable period (e.g., May

1–July 31), while another State may

only require one sample for the entire

year. Alternatively, another State may

be concerned about trichloroethylene

and require four quarterly samples.

C. What Are the State Recordkeeping

Requirements?

The standard record keeping

requirements for States under SDWA

apply to the arsenic rule (§ 142.14).

Today’s rule does not modify or require

additional recordkeeping requirements.

States with primacy must keep all

records of current monitoring

requirements and the most recent

monitoring frequency decision

pertaining to each contaminant,

including the monitoring results and

other data supporting the decision, and

the State’s findings based on the

supporting data and any additional

bases for such decision. These records

must be kept in perpetuity or until a

more recent monitoring frequency

decision has been issued.

D. What are the State Reporting

Requirements?

Currently, States with primary

enforcement responsibility must report

to EPA information under § 142.15

regarding violations, variances and

exemptions, and enforcement actions

and general operations of State public

water supply programs. Today’s rule

does not modify or require additional

reporting requirements. The State

reporting requirements that will apply

to the arsenic standard are the same as

all other regulated inorganic

contaminants.

E. When Does a State Have To Apply for

Primacy?

To maintain primacy for the Public

Water Supply Supervision (PWSS)

program and to be eligible for interim

primacy enforcement authority for

future regulations, States must adopt

today’s final rule. A State must submit

a request for approval of program

revisions that adopt the revised MCL

and implement regulations within two

years of promulgation, unless EPA

approves 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.

F. What Are Tribes Required To Do

Under This Regulation?

Currently, the Navajo Nation is the

only Tribe with primacy for all the

National Primary Drinking Water

Regulations, and it will be subject to the

same requirements as a State. There are

no other Federally recognized Indian

tribes with primacy to enforce any of the

drinking water regulations. EPA’s

Regions have responsibility for

implementing the rules for all Tribes

except the Navajo Nation under section

1451(a)(1) of SDWA. To obtain primacy

authority for the revised arsenic MCL,

Tribes must submit a primacy

7024 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

application to regulate inorganic

contaminants (i.e., the Phase II/V rule).

V. Responses to Major Comments

Received

A. General Comments

1. Sufficiency of Information and

Adequacy of Procedural Requirements

To Support a Final Rule

A number of commenters challenged

EPA’s basis for promulgating a final

rule, arguing that (1) there was

insufficient technical information

provided with the proposed rule, (2)

various expert technical evaluations

were not adequately considered, or (3)

procedural requirements (e.g.,

Unfunded Mandates Reform Act

(UMRA), Small Business Regulatory and

Enforcement Flexibility Act (SBREFA))

have not been fully satisfied. EPA

respectfully disagrees, and we believe

that the record of our actions is

sufficient to support a final rulemaking.

Other portions of the preamble to

today’s rule explain the technical

evaluations performed in support of the

proposed rule and the revised analyses

conducted, based on comments and

information submitted in response to

the proposal. EPA recognizes that

various questions about different

aspects of this rulemaking have been the

subject of an array of analyses and

reports by various investigators. This

area of investigation has also been

dynamic, and there will undoubtedly be

additional analyses after promulgation

of the final rule that the Agency will

need to consider in light of the

requirement to periodically review (and

revise as appropriate) all final drinking

water regulations as provided by section

1412(b)(9) of SDWA. However, we

believe that we have fully and

appropriately considered all available

and relevant information for the final

rulemaking and do not need to

repropose as several commenters

suggest. We also believe that we have

fully satisfied the procedural

requirements of the pertinent statutory

and Executive Order requirements.

Section VI. of the preamble to today’s

final rule discusses these procedural

requirements in more detail.

2. Suggestions for Development of an

Interim Standard

Several commenters advocated an

interim standard in view of the

uncertainties associated with the health

effects data, the costs of compliance

with the final rule, and concerns over

the interpretation of the ‘‘antibacksliding’’ provision of SDWA related

to review and revision of existing

standards (section 1412(b)(9)). While

EPA appreciates these concerns, we do

not believe that they provide a sufficient

basis for concluding that an interim

standard be set. We agree with the

recommendation of the National

Academy of Sciences that there is

sufficient information available now to

develop a new lower drinking water

standard for arsenic. We further believe

that available information is sufficient

to support a final, rather than an

interim, standard. Finally, there is

simply no authority in SDWA to

establish an interim standard that does

not comply with sections 1412(b)(4) and

1412(b)(6). However, we are committed

to reviewing and revising, if

appropriate, the final standard every six

years (or sooner, if pertinent new

information becomes available). In so

doing, we must ensure that the revised

standard provides for ‘‘equal or greater

protection to the health of persons’’ as

compared to the standard it replaces.

3. Public Involvement and Opportunity

for Comment

Some commenters questioned

whether the extent of public

involvement in the development of

today’s rule was sufficient. Some

commenters also suggested that the

Agency use a negotiated rulemaking

process for the final rule pursuant to the

Federal Advisory Committee Act

(FACA). EPA believes that public

involvement throughout the

development of this rule, has been

extensive and far-reaching. As discussed

in section I.N. earlier in this preamble,

during the period 1996–2000, EPA

conducted a number of Agency

workgroup meetings on arsenic and

advertised six stakeholder meetings

(held in five locations) in the Federal

Register. Five States also provided

written comments on implementation

issues during the workgroup process.

Representatives of eight Federal

agencies, 19 State offices, 16

associations representing the breadth of

the public water system community, 13

corporations, 14 consulting engineering

companies, two environmental

organizations, three members of the

press, 37 public utilities and cities, four

universities, and one Indian tribe

attended the stakeholder meetings on

arsenic. EPA presented an overview of

the arsenic rulemaking to over 900

Tribal representatives in 1998 and

provided more detailed information in

1999 to 25 Tribal council members and

water utility operators from 12 Indian

tribes. In addition, EPA provided

updates on our rulemaking activities at

national and regional meetings of

various groups and trade associations.

We also participated in the American

Water Works Association’s (AWWA)

technical workgroup meetings. As part

of the Small Business Regulatory and

Enforcement Flexibility Act (SBREFA)

process, EPA also received valuable

input from discussions with small entity

representatives during SBREFA

consultations for the arsenic rule. EPA

obtained recommendations from the

National Drinking Water Advisory

Council (NDWAC) on the rule as a

whole as well as on our approach

benefits analysis and small systems

affordability. We also posted discussion

papers produced for our stakeholder

interactions on the EPA Office of

Ground Water and Drinking Water

(OGWDW) Internet site and sent them

directly to participants at stakeholder

meetings and others who expressed

interest. EPA also received over 1,100

comments on the June 22, 2000

proposed rule. EPA took these

comments into consideration in

developing today’s final rule.

EPA agrees that the FACA-negotiated

rulemaking process has been an

effective one in the past for other

complex rulemakings. However, EPA

does not believe that a negotiated

rulemaking at this point is consistent

with the deadlines set by Congress for

this rulemaking. We would point out,

however, that the Agency has taken a

number of active steps to ensure broadbased stakeholder involvement, as

described previously, and has solicited

expert points of view outside the

Agency. Some of these actions included

a charge to the National Academy of

Sciences (NAS) to fully explore the most

current health effects issues. A charge

was also given to EPA’s Science

Advisory Board (SAB) to review key

aspects of the proposed rule and EPA’s

underlying rationale. EPA believes that

this combination of actions ensured that

full and complete stakeholder

involvement occurred, and that further

negotiations would be unnecessary.

4. Relation of MCL to the Feasible Level

Several commenters questioned the

feasible level of 3 μg/L contained in the

proposed rule. Commenters believed

that EPA has not accurately assessed the

capabilities of laboratories to achieve

the practical quantitation level (PQL) or

of treatment technologies to reliably and

consistently treat down to the feasible

level. EPA disagrees and still believes

that 3 μg/L is feasible from the

standpoints of both analytical methods

and treatment technologies. EPA

discusses these issues in more detail in

section III.B. of the preamble to today’s

final rule. Many of the comments on the

proposed rule were concerned by the

close proximity of the proposed

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7025

standard (5 μg/L) to the proposed

feasible level (3 μg/L). However,

comments regarding whether or not the

proposed standard of 5 μg/L is feasible

are not particularly germane to the

setting of the final standard, which is

well above any level identified by most

commenters as being feasible.

5. Relationship of MCL to Other

Regulatory Programs

Many commenters expressed

concerns about the possible impact of a

new revised drinking water standard for

arsenic on other regulatory standards for

arsenic. In particular, several

commenters recommended that EPA

consider the prospective costs of future

Comprehensive Environmental

Response, Compensation and Liability

Act (CERCLA) site clean-up actions,

RCRA hazardous waste management

costs, or national permit discharge

elimination system (NPDES) permits to

the extent that a new arsenic in drinking

water standard leads to more stringent

regulatory actions under those

respective statutes. EPA disagrees and

notes that SDWA specifically excludes

from consideration under the HRRCA

such prospective, ancillary costs in

developing a drinking water standard

(see section 1412(b)(3)(C) of SDWA).

6. Relation of MCL to WHO Standard

Several commenters on the proposed

rule expressed a concern that the

drinking water standard in the U.S.

should be no more stringent than the

standard developed for the World

Health Organization (WHO). This

comment dealt primarily with the

proposed level of 5 μg/L and does not

apply to the final MCL of 10 μg/L,

which is identical to the WHO standard.

However, while the thrust of the

comment is now moot, EPA notes that

the basis for the final MCL and the

WHO standard are different. EPA’s

standard is based on consideration of all

of the risk management factors required

to be evaluated under SDWA (e.g., risk,

costs, benefits, treatment technology

and analytical method capabilities,

small systems affordability, etc.) while

the WHO standard is based solely on

health effects, without regard to any

implementation considerations. Further,

the health basis for the WHO standard

is primarily an assessment of arsenicinduced skin cancer, whereas there are

a number of health endpoints of concern

in EPA’s analysis including lung and

bladder cancer. In summary, the two

levels (the WHO standard and EPA’s

final MCL) happen to be the same but

a possible future change in the WHO

standard would not necessarily require

a revision to EPA’s MCL, for the reasons

just discussed.

7. Regulation of Non-Transient NonCommunity Water Systems (NTNCWSs)

Several commenters objected to the

approach outlined in the proposed rule

for addressing NTNCWSs (monitoring

and reporting only) and pointed out the

need for consistency in coverage of

NTNCWSs in EPA’s rules. These

commenters noted that the rules

originally promulgated in 1976 (arsenic

and radionuclides) have not required

coverage of NTNCWSs, whereas more

recently promulgated rules have. In

addition, EPA’s proposed radon rule

suggested not covering NTNCWSs and

the recently promulgated radionuclides

rule did not require coverage of

NTNCWSs, but instead deferred this

issue for future resolution. EPA agrees

that the outcomes of its recent decisions

with respect to coverage of NTNCWSs

have been different. However, we

considered the merits of each

rulemaking on a case-by-case basis

using a consistent set of criteria, namely

the cost/benefit analysis required under

section 1412(b)(4).

For the proposed arsenic rule, EPA

carefully examined the risks posed by

NTNCWSs and concluded preliminarily

that the risks were such that, without

coverage, consumers of water from

NTNCWSs were projected to be within

the target risk range. EPA acknowledges,

however, that there is uncertainty

associated with its information about

exposure patterns for consumers of

water from NTNCWSs and the

demographics of these facilities. Thus,

our understanding of the health risks

(and associated possible benefits of

removal) to consumers of water from

NTNCWSs is uncertain. In the case of

arsenic, EPA believes the additional

uncertainty in the overall risk analysis

argues against any finding at this point

that these systems are substantially

different in terms of exposure than

community water systems. EPA also

believes the decision to cover these

facilities in today’s rule is supported by

consideration of the risks to certain

subpopulations within the general

population, such as children who

consume water at day care facilities or

schools that are served by NTNCWSs.

Concerns were also expressed about

whether commenters were provided

with sufficient information about the

costs of full coverage. These

commenters noted that EPA could not,

without violating the notice and

comment provisions of the

Administrative Procedure Act, move to

full coverage of these facilities in the

final rule. EPA disagrees with this

comment. The proposal clearly

indicated that full coverage of

NTNCWSs was an option on which

comment was being requested and the

supporting documents provided

complete information about the costs of

full coverage. (EPA, 2000h, see Table 6–

9).

8. Extension of Effective Date for Large

Systems

Commenters were generally

supportive of EPA’s proposed national

determination (pursuant to section

1412(b)(10) of SDWA) that water

systems covered by the rule, serving less

than 10,000 persons, and needing to

make capital improvements to comply

with the new standard would need more

than 3 years from the time of rule

promulgation to accomplish this. Thus,

the proposed rule suggested allowing a

two-year extension for compliance with

the new standard, beyond the three

years provided after the promulgation

date. However, several commenters

suggested that this finding and the

additional two years for compliance

should be applicable to all systems,

including those serving more than

10,000 persons, since extensive

planning, design, and new equipment

will also generally be needed by larger

systems in a similar situation to comply

with the new standard. EPA was

persuaded by these comments, and has,

as part of the implementation

requirements for today’s final rule,

elected to apply this two-year extension

to all facilities covered by today’s rule.

B. Health Effects of Arsenic

1. Epidemiology Data

Many commenters were critical of the

Taiwan epidemiologic study as a basis

for EPA decision making, quantitative

dose-response assessment, extrapolation

of the dose-response from the observed

range of exposure, and application of

the same risk estimate to the U.S.

population. No commenters challenged

the EPA conclusion that this study and

the other epidemiologic studies together

show that arsenic is carcinogenic to

humans. Some supported the risk

analysis in the proposed rule and the

notice of data availability (NODA)

because it is relatively risk averse;

others had criticisms.

The following issues were raised

about the use of the Taiwan risk

assessment to represent U.S. risk:

Arsenic exposure from food and via

cooking with contaminated water in

Taiwan is higher than is typical for the

U.S. population; exposure groupings

were made at the village level and were

assigned the median of the

7026 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

concentration of arsenic measured in

the wells serving that village; not all

wells serving all villages were measured

and well concentrations varied

seasonally; the Taiwan population was

a rural population that was not well

nourished, having deficits of selenium,

possibly methionine or choline (methyl

donors), zinc and other essential

nutrients; and the Taiwan population

may have unknown differences in

genetic polymorphisms from the U.S.

population. Similar concerns were

raised about the South American

studies.

Commenters also cited studies in the

U.S. (Lewis et al., 1999, Utah

population) and Europe (Buchet et al.,

1999; Kurttio et al., 1999) as support for

the position that the risks from the

Taiwan study overestimated the risks in

the U.S.

Many commenters were convinced

that the Lewis et al. (1999) study of a

U.S. population is the best study to use

in estimating U.S. risk. Since the Utah

study did not observe cancer outcomes

that one would expect if risks were as

large as the Taiwan or South American

studies suggest, these commenters

believe that risks estimates from studies

of populations outside of the U.S.

overestimate U.S. risks.

Scientists generally agree that high

doses of arsenic are associated with

various cancer and noncancer health

effects in humans. Epidemiology studies

in humans demonstrate that arsenic

induces skin and internal (e.g., bladder

and lung) cancers and non-cancer

effects such as skin keratoses and

vascular abnormalities when ingested in

drinking water at high doses.

The epidemiologic investigations that

have been most thorough in

investigating the exposure and effects

on humans of ingesting ground water

contaminated with arsenic are those of

populations in Taiwan (Chen et al.,

1985; 1988; 1992; Wu et al., 1989),

Argentina (Hopenhayn-Rich et al., 1996;

1998), Chile (Smith et al., 1998), and the

U.S. (Lewis et al., 1999). All of these

and other, smaller studies have been

considered in the Agency’s

deliberations on this rule.

The studies from Taiwan, Chile,

Argentina and the U.S. employed the

proper endpoints, selected correct study

groups and grouped the people into

discrete exposure groups. They also

used acceptable methods and accounted

for some known confounders. These

studies, due to their relative sizes,

varied in their statistical power to detect

differences. The Utah study (Lewis et

al., 1999) contained 4,000 people while

the Taiwan study had approximately

40,000 people and the two South

American studies each had over 200,000

people. All of these epidemiology

studies were ecological and

retrospective studies. The Taiwan and

South American studies had no

individual exposure data. The Utah

study associated persons with wells that

had measured concentrations though

exposure was calculated based on both

level of arsenic and length of exposure.

The Utah study followed exposed

individuals to discern causes of later

disease through carefully kept church

records.

The Agency chose to make its

quantitative estimates of risk based on

the Taiwan study. This choice was

endorsed by the EPA Science Advisory

Board (SAB, 2000q; NRC, 1999). The

database from Taiwan has the following

advantages: Mortality data were drawn

from a cancer registry; arsenic well

water concentrations were measured for

each of the 42 villages; there was a large,

relatively stable study population that

had life-time exposures to arsenic; there

are limited measured data for the food

intake of arsenic in this population; ageand dose-dependent responses with

respect to arsenic in the drinking water

were demonstrated; the collection of

pathology data was unusually thorough;

and the populations were quite

homogeneous in terms of lifestyle.

Studies in Argentina and Chile also

showed lung and bladder risk of similar

magnitude at comparable levels of

exposure. EPA recognizes that there are

problems with the Taiwan study that

introduce uncertainties to the risk

analysis such as: the ecological study

design; the use of median exposure data

at the village level; the low income and

relatively poor diet of the Taiwanese

study population (high levels of

carbohydrates, low levels of protein,

selenium and other essential nutrients);

and high exposure to arsenic via food

and cooking water.

As urged by many commenters, the

Agency has considered and made

adjustments in its dose-response

assessment to reflect the quantitative

effect of the high Taiwanese exposure to

arsenic via food and cooking water. The

Agency made an adjustment to the

lower bound risk estimates to take into

consideration the effect of exposure to

arsenic through water used in preparing

food in Taiwan. In addition, an

adjustment was made to the lower

bound risk estimates to take into

consideration the relatively high arsenic

concentration in the food consumed in

Taiwan as compared to the U.S. We also

considered several additional factors

qualitatively in our final decision. These

included the effect of the median well

exposure data from the Taiwan study

and the effects of nutritional factors

such as selenium and methyl donors.

However, we did not feel that there

were sufficient data to account for these

factors quantitatively.

The U.S. population cannot be

considered to be made up entirely of

well-nourished, genetically uniform

persons. People of the Asian and Pacific

Islander group make up about 4%

(approximately 11 million) of the more

than 270 million people in the U.S.

(U.S. Census Bureau, 2000). In addition,

there is a significant portion of the U.S.

population living in poverty with poor

nutrition. Thus, the Agency continues to

believe that the Taiwan study is

appropriate as a basis for risk

assessment. The fact that the whole of

the Taiwanese population was

nutritionally vulnerable is a factor that

the Agency has considered qualitatively

as an uncertainty in risk assessment that

may on average lead to overestimation

of risk when applied to the U.S.

The Utah study (Lewis et al., 1999)

did not find any excess bladder or lung

cancer risk after exposure to arsenic at

concentrations of 14 to 166 μg/L. An

important feature of the study is that it

estimated excess risk by comparing

cancer rates among the study population

in Millard County, Utah to background

rates in all of Utah. But the cancer rates

observed among the study population,

even those who consumed the highest

levels of arsenic, were significantly

lower than in all of Utah. This is

evidence that there are important

differences between the study and

comparison populations besides their

consumption of arsenic. One such

difference is that Millard County is

mostly rural, while Utah as a whole

contains some large urban populations.

Another difference is that the subjects of

the Utah study were all members of the

Church of Jesus Christ of Latter Day

Saints, who for religious reasons have

relatively low rates of tobacco and

alcohol use. For these reasons, the

Agency believes that the comparison of

the study population to all of Utah is

not appropriate for estimating excess

risks. An alternative method of analysis

is to compare cancer rates only among

people within the study population who

had high and low exposures. The

Agency performed such an analysis on

the Utah data, using the statistical

technique of Cox proportional hazard

regression (U.S. EPA, 2000x; Cox and

Oakes, 1984). The results showed no

detectable increased risk of lung or

bladder cancers due to arsenic, even

among subjects exposed to more than

100 μg/L on average. On the other hand,

the excess risk could also not be

distinguished statistically from the

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7027

levels predicted by model 1 of Morales

et al. (2000). These results show that the

Utah study is not powerful enough to

estimate excess risks with enough

precision to be useful for the Agency’s

quantitative arsenic risk analysis.

Furthermore, the SAB noted that

‘‘(a)lthough the data provided in

published results of the Lewis, et al.,

1999 study imply that there was no

excess bladder or lung cancer in this

population, the data are not in a form

that allows dose-response to be assessed

dependably’’ (EPA, 2000q). Other

studies in the U.S. (Morton et al., 1976;

Valentine et al., 1992; Wong et al., 1992)

and Europe (Buchet et al., 1999; Kurttio

et al., 1999) were also considered in

EPA’s evaluation of the risk from

arsenic. However, these studies were

not sufficient to develop a doseresponse relationship.

2. Dose-Response Relationship

Numerous comments were received

about the quantitative estimation of

potential cancer risks to U.S.

populations from drinking water

exposure to arsenic. Concerns were

raised about the extrapolation of the

dose (exposure)—response relationship

observed in a study of cancer incidence

in an arseniasis-endemic area of Taiwan

with high levels of arsenic in water

(Chen et al., 1988; Wu et al., 1989; Chen

et al., 1992) to estimate potential

response in the U.S. to arsenic in water

at lower levels.

Some commenters asked whether it is

appropriate to assume a linear dose

response for arsenic given that arsenic

does not appear to be directly reactive

with DNA. Other commenters urged

strict adherence to the linear approach,

and recommended choosing an MCL

that is below the 1/10,000 level of

estimated risk based on that approach.

Some commenters also noted that

independent scientific panels (EPA,

2000q; NRC, 1999; EPA, 1997e; EPA,

1988) who have considered the Taiwan

study have raised the caution that using

the Taiwan study to estimate U.S. risk

at lower levels may result in an overly

conservative estimation of U.S. risk. The

independent panels have each said that

below the observed range of the high

level of contamination in Taiwan the

shape of the dose-response relationship

is likely to be sublinear. Thus, an

assumption that the effects seen per

dose increment remain the same from

high to low levels of dose may overstate

the U.S. risk. Some commenters have

urged that the Agency model the doseresponse relationship as a sublinear one,

rather than as a linear one as in the

proposal and NODA for the rule. These

commenters consider adherence to the

linear model as a failure of the Agency

to use the best available, peer-reviewed

science as required by SDWA.

After consideration of the arguments

made by the commenters, the Agency

continues to believe that the best

approach, given the uncertainties

associated with the available data, is to

use the linear approach to set the MCLG

for arsenic. In the proposal and the

NODA, EPA discussed the fact that the

available data on arsenic’s carcinogenic

mode of action point to several potential

modes of action, but which one is

operative is unknown. For this reason,

the data do not support use of an

alternative to linearity. The Agency

recognizes that the dose-response

relationship may be sublinear. The

Agency has considered both a linear

extrapolation and a nonlinear approach

in the selection of an MCL in this final

rule. (see section III.D.1.g. and the

comment response document for a

thorough discussion of the Agency’s

position on the dose-response

assessment for arsenic.)

3. Suggestions That EPA Await Further

Health Effects Research

Several commenters expressed the

opinion that EPA should delay setting a

standard for arsenic until more research

studies have been completed. These

commenters focused on research areas

such as health effects (especially at low

doses), the mode of action, and the

dose-response curve. Other commenters

questioned EPA’s support of new

research and tracking of ongoing

research.

Since developing the Arsenic

Research Plan as required by the 1996

SDWA amendments, EPA and

stakeholders have established a

substantial research program.

Significant research has been

completed, and further research is

underway. EPA is tracking the progress

of ongoing research and will make

research results available to the public.

EPA is committed to issuing the arsenic

regulation based on best available

science and believes that the research

currently available is sufficient to do so.

EPA believes that the research

underway may provide important new

data for future rulemakings on arsenic.

However, EPA does not believe that a

determination on the arsenic MCL must

be delayed until this research is

complete. Indeed, the U.S. Court of

Appeals for the District of Columbia

Circuit found that EPA:

cannot reject the ‘‘best available’’ evidence

simply because of the possibility of

contradiction in the future by evidence

unavailable at the time of action—a

possibility that will always be present’’ and

that ‘‘[a]ll scientific conclusions are subject

to some doubt; future hypothetical findings

always have the potential to resolve the

doubt. What is significant is Congress’s

requirement that the action be taken on the

basis of the best available evidence at the

time of rulemaking. The word ‘‘available’’

would be senseless if construed to mean

‘‘expected to be available at some future

date’’ (Chlorine Chemistry Council v. EPA,

206 F.3d 1286, 1290–91 (D.C. Cir. 2000)).

In the future, as part of the 6-year

review process, the Agency will

evaluate new data to determine if the

MCLG and/or MCL promulgated in

today’s regulation should be revised.

Research pertaining to arsenic in the

drinking water is a priority for the EPA.

In addition, EPA supports and

encourages other organizations to

sponsor new epidemiology and

toxicology studies on arsenic. The

nature of scientific research is that as

each study attempts to address or

resolve a particular issue, it also raises

more questions for investigation. EPA

recognizes that even when the ongoing

set of studies are complete, more are

likely to follow. Uncertainty is inherent

in science; at no point will ‘‘all’’

research be finished and ‘‘all’’ questions

be answered.

4. Sensitive Subpopulations

Some commenters encouraged EPA to

set the arsenic standard as low as

possible to protect vulnerable

populations. These commenters felt that

EPA should consider human

development and reproduction and

variously defined vulnerable

populations as persons with immune,

cardiovascular, and nervous system

disorders, children, low-income people,

Native Americans, diabetics, and

geriatric populations.

The 1996 SDWA amendments include

specific provisions in section

1412(b)(3)(C)(i)(V) that require EPA to

assess the effects of a 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. The

NRC subcommittee (NRC, 1999) noted

that there is a marked variation in

susceptibility to arsenic-induced toxic

effects which may be influenced by

factors such as genetic polymorphisms

(especially in metabolism), life stage at

which exposures occur, sex, nutritional

status, and concurrent exposures to

other agents or environmental factors.

EPA shares the view of the NRC report

7028 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

which 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. The EPA

agrees with NRC that there is not

enough information to make risk

conclusions regarding any specific

subpopulations. However, EPA believes

it is appropriate to consider effects on

infants due to their greater consumption

of water per body weight and is

considering whether to issue a health

advisory that will address this issue.

A study of a population in Chile

exposed to about 800 μg/L in its

drinking water for a period of years

showed significant association with this

exposure and fetal and infant mortality

that declined to background when the

water was treated to remove arsenic.

This study was cited by a commenter as

indicating more general sensitivity of

fetuses and infants. The dose was one

that had a range of significant arsenic

toxicity effects on the adult population.

It is logical that fetuses of mothers so

exposed would be affected and infants

would have received several times the

adult exposure per kg body weight and,

consequently, more toxicity. This study

does not indicate disproportionate

effects on fetuses or infants at low

doses. Once the water was treated the

effects declined to background

(Hopenhayn-Rich et al., 2000).

5. EPA’s risk analysis

Several commenters felt that EPA did

not follow the NRC recommendations

that ‘‘the final calculated risk should be

supported by a range of analyses over a

fairly broad feasible range of

assumptions’’, misinterpreted the NRC

report, or relied solely on the NRC

report and thus did not do an

appropriate risk assessment for arsenic.

Others viewed the NRC report as lacking

peer review or as being politically

motivated.

The SAB (EPA, 2000q, pgs. 2–3)

discussed EPA’s use of the NRC report.

In the cover letter to the Administrator

they stated:

* * * The NRC also noted a number of

factors that likely differ between the

Taiwanese study population and the U.S.

population and which might influence the

validity of arsenic cancer risk estimates in

the United States. Even though the Agency

did its own risk characterization (i.e., they

combined the NRC risk factors with U.S.

exposure information and arsenic occurrence

distributions to obtain a range of risks for use

in their benefits analysis), they chose not to

quantitatively take any of these factors into

account at this time.

The Panel agrees with conclusions reached

by the NRC in its 1999 report on arsenic,

especially their conclusion that ‘‘there is

sufficient evidence from human

epidemiological studies * * * that chronic

ingestion of inorganic arsenic arsenic [sic]

causes bladder and lung, as well as skin

cancer.’’ The NRC also stated that currently

the Taiwanese data are the best available for

quantifying risk * * *. We note, however,

that this Panel does not believe that

resolution of all these factors can nor must

be accomplished before EPA promulgates a

final arsenic rule in response to the current

regulatory deadlines. However, resolution of

the critical factors * * *. in time for the next

evaluation cycle for the arsenic regulation

should be considered as a goal.

In closing the cover letter to the

Administrator, the SAB stated:

Specifically, the majority of the Panel

members felt that there is adequate basis for

the Agency to consider use of its

discretionary authority under the Safe

Drinking Water Act of 1996 to consider MCLs

other than the proposed 5 μg/L.

* * * The ultimate risk number derived

from the Taiwanese study has proven very

sensitive to the decision about the

appropriateness of the comparison

population. This of course, has important

implications for the use of the data to

estimate risk in the U.S. Also a study in Utah

suggests that some U.S. populations may be

less susceptible to the development of

cancer, than those in Taiwan * * *. Also, a

recently published study suggests that the

incremental increases in lung and bladder

cancers observed in the Taiwan study are of

roughly the same magnitude, rather than the

NRC’s inference of a potentially two- to fivefold greater rate of lung cancer relative to

bladder cancer.

As noted by the NRC, the mechanisms

associated with arsenic-induced cancer most

likely have a sublinear character, which

implies that linear models, such as those

used by the Agency, overestimate risk * * *.

Nonetheless, the Panel agrees with the NRC

that available data do not yet meet EPA’s new

criteria for departing from linear

extrapolation of cancer risk.

The NRC Subcommittee on Arsenic in

Drinking Water explored a number of

model approaches using the Taiwan

epidemiology data for bladder cancer.

Although there are indications that the

dose-response relationship for arsenic

may be nonlinear at low doses, a

convincing biological argument for

selecting a nonlinear model is not yet

available. Thus, according to EPA’s draft

1996 guidelines and consistent with the

1986 guidelines, EPA determined that a

point of departure approach was most

appropriate to estimate low-dose risks.

EPA agreed with NRC’s choice of the

Poisson model. In the NODA, based on

the Morales et al. study (2000), EPA

conducted a re-analysis of the bladder

and lung cancer data using a Poisson

model with no comparison population

to estimate points of departure for each

health endpoint. In addition to the reanalysis of bladder and lung cancer risk,

EPA did a sensitivity analysis of the

effect of exposure to arsenic through

water used in preparing food in Taiwan.

In response to comments received on

the proposed rule and the NODA, EPA

has also analyzed the effect of exposure

to arsenic through food and considered

the effect of village level exposure data.

In summary, EPA’s final risk calculation

is supported by analyses of the effect of

various assumptions and uncertainties

on the risk estimate and reflects the best

available science.

EPA believes that it has done a

thorough risk analysis on arsenic.

Arsenic health risks have remained a

high priority at EPA for over 20 years,

and EPA scientists have closely

followed all scientific developments.

EPA established four independent

scientific panels to evaluate arsenic

health risks (EPA, 2000q; NRC, 1999;

EPA, 1997e; EPA, 1988) and provided a

sense of the views of the broader

scientific community. EPA participated

in conducting one of the major cancer

mortality studies available on arsenic

(Lewis et al., 1999). In the proposed rule

and NODA, EPA used the 1999 NRC

report’s analysis of the Taiwan data as

well as other published scientific papers

to characterize the potential health

hazards of ingested arsenic. The NRC

report represents a thorough

examination of the best available, peer

reviewed science through the late 1990s.

Other studies that were important in

EPA’s analysis were the Utah study

(Lewis et al., 1999) and the Morales et

al. (2000) study. In selecting the

proposed MCL, EPA considered the

uncertainties of the quantitative doseresponse assessment, particularly the

possible nonlinearity of the doseresponse. EPA also considered the

unquantifiable risks from arsenic such

as noncancer effects. In response to

commenters, EPA expanded its analysis

of the Utah study (U.S. EPA, 2000x) and

delved further into the uncertainties in

the Taiwan data. The Agency made an

adjustment to the lower-bound risk

estimates to take into consideration the

effect of exposure to arsenic through

water used in preparing food in Taiwan.

In addition, an adjustment was made to

the lower-bound risk estimates to take

into consideration the relatively high

arsenic concentration in the food

consumed in Taiwan as compared to the

U.S. EPA also investigated the effect of

the ecological exposure data on its risk

estimates. When villages with only one

arsenic measurement were removed

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7029

from the data set (on the theory that the

exposure data was too uncertain), or

when village means instead of medians

were used for the exposure estimates,

there was no statistically significant

change in the estimated point of

departure, using Model 1 of Morales et

al. (2000). In summary, EPA believes

that it has completed a thorough risk

analysis on arsenic that used the best

available, peer reviewed science.

The NRC subjected their draft report

to a very rigorous external peer review

using its own procedures that are well

established and generally acknowledged

as being independent and objective. The

SAB also reviewed the NRC report and

EPA’s risk analysis, which was, in part,

based on the NRC report. In addition,

the public was provided an opportunity

to comment on the EPA risk analysis as

a part of the arsenic proposal and

NODA.

EPA disagrees that the NRC report

was politically motivated. The NRC

Subcommittee on Arsenic in Drinking

Water was composed of 16 highly

respected scientific experts. EPA

believes that this panel produced an

impartial analysis of the data available

on the toxicity of arsenic.

6. Setting the MCLG and the MCL

Some commenters were confused

about the difference between MCLGs

and MCLs, how EPA sets MCLGs and

MCLs based on legal, scientific, and

policy principles, and the relationship

between the MCLG and costs and

benefits. Other commenters were

concerned about a perceived ‘‘antibacksliding’’ provision for MCLGs and

MCLs in SDWA.

In accordance with SDWA, standards

set for contaminants consist of two

components, a maximum contaminant

level goal (MCLG) and a national

primary drinking water regulation

(NPDWR) (section 1412(b)(1)(A)), which

specifies either ‘‘a maximum

contaminant level (MCL) for such

contaminant which is generally set as

close to the maximum contaminant

level goal as is feasible’’ (section

1412(b)(4)(B)) or a treatment technique

if ‘‘it is not economically or

technologically feasible to ascertain the

level of the contaminant’’ (section

1412(b)(7)(A)).

SDWA defines an MCLG 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)(A)). MCLGs for all

carcinogens are set at zero unless

adequate scientific data support a higher

MCLG. In accordance with the SDWA,

the MCLG is based on the best available

peer reviewed science. An MCLG is a

goal, not a regulatory limit that the

Agency expects to be attained by water

systems.

The MCLG must be proposed

simultaneously with a national primary

drinking water regulation (section

1412(a)(3)), which specifies a maximum

contaminant level (MCL) as close to the

MCLG as technically feasible. The MCL

is the enforceable standard. SDWA

allows EPA to make an exception to

setting the MCL as close to the MCLG

as is feasible where the ‘‘Administrator

determines * * * that the benefits of a

maximum contaminant level * * *

would not justify the costs of complying

with the level.’’ In this case, 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)). This

exception was used to set the MCL for

arsenic. EPA found that at the feasible

level of 3 μg/L, the benefits of

compliance did not justify the costs.

The Agency determined that an MCL of

10 μg/L maximizes the health risk

reduction benefits at a cost that is

justified by the benefits (see preamble

discussion of the risk management

decision that was made for arsenic in

section III.F.)

Some commenters argued that EPA

sets the MCL within a risk-range of 10¥4

to 10¥6 without proper regard to the

statutory requirements discussed above.

This is not the case. As noted in the

proposal, EPA has historically

considered this risk range as protective

of public health, and accordingly has

sought to ensure that drinking water

standards are within this risk range.

However, the risk-range represents a

policy goal for EPA, and is not a

statutory factor in setting an MCL. In the

case of arsenic, EPA did the benefit-cost

analysis required by the statute. Having

found that the benefits of an MCL at the

feasible level were not justified by the

costs, EPA set the MCL at 10 μg/L. This

MCL maximizes health risk reduction

benefits at a cost that is justified by the

benefits.

EPA is required to review and revise

as appropriate, each national primary

drinking water regulation, at least every

6 years. Revisions to current regulations

‘‘shall maintain, or provide for greater

protection of the health of persons’’

(section 1412(b)(9)). When new

scientific data become available, the

Agency may reevaluate the MCLG and

MCL.

C. Occurrence

The principal concerns raised by the

commenters and our responses are as

follows:

1. Occurrence data

Several commenters expressed

concern that EPA estimated occurrence

using data from only 25 States and that

the national estimate was thus not as

robust as it should have been. Many of

these commenters suggested that EPA

should request data from all States/more

systems before issuing the final rule.

It is true that we based our occurrence

estimate on data from only 25 States.

However, we believe that we have

compiled the most comprehensive and

accurate occurrence estimate possible

with currently available data, and that

this estimate adequately supports our

various analyses and final decisions.

For our occurrence analysis, we relied

on data submitted voluntarily by State

drinking water agencies. In doing so, we

collected the largest available database

on arsenic in drinking water, consisting

of almost 77,000 observations from more

than 26,600 public water systems in 25

States. We received but did not use data

from six States (Florida, Idaho, Iowa,

Louisiana, Pennsylvania, and South

Dakota), because the data either could

not be linked to PWSs; did not indicate

if results were censored; were all zero;

did not provide analytical or reporting

limits; or were rounded to the nearest 10

μg/L.

In response to our request in the

proposed rule for additional occurrence

data, we received additional data from

several States. However, in each case,

the submitted data either corresponded

closely to observations already in our

data set (California, New Mexico, Utah),

or were of the wrong kind or insufficient

quantity to use in our estimation (Iowa,

Maryland, Nebraska, Oklahoma,

Vermont, West Virginia).

Of the States from whom we did not

receive usable data, we believe that

many do not have databases of the kind

and quality that we would need for our

occurrence analysis. We therefore could

not have obtained such information

from other States without requiring, in

some instances, new monitoring to be

undertaken and new data to be

compiled.

In forming our occurrence estimate,

we did not ignore States for which we

have no suitable data. We accounted for

these States by assigning regional

occurrence distributions to them. Our

resulting national estimates compare

relatively closely with those developed

by the utility industry and by the U.S.

Geological Survey (EPA, 2000r).

Some commenters indicated EPA

should not use data from the U.S.

Geological Survey’s National Ambient

Water Quality Assessment (NAWQA) or

EPA’s NIRS, SDWIS, or Rural Water

7030 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

Survey (RWS) to estimate occurrence. In

forming our occurrence estimates, we

used arsenic concentrations drawn only

from our 25-State arsenic compliance

monitoring database. We did not use

observations from NAWQA, SDWIS,

RWS, NAOS, NIRS, NOMS, Community

Water System Survey (CWSS) or any

other surveys or studies. As the

preamble of the proposed rule (65 FR

38888 at 38903) states, we used National

Organic Monitoring Survey (NOMS),

RWS, and the 1978 CWSS in previous

arsenic occurrence analyses, but did not

use them for the present analysis

because of their age and relatively high

detection limits. The only information

we used from SDWIS was the type and

size of particular systems, and the

numbers of systems and population

served in different categories of systems.

We used NAWQA, NAOS and NIRS

only for comparison to our finished

results.

2. Occurrence Methodology

Some commenters stated their belief

that EPA had underestimated national

occurrence because they believe that

EPA did not have enough data with

which to develop the estimate.

Commenters also believed that, since

the national occurrence is

underestimated, noncompliance/cooccurrence are also underestimated.

We do not agree that we have

underestimated arsenic occurrence. We

have the largest existing database of

arsenic in drinking water, with almost

77,000 observations from more than

26,600 public water systems in 25

States. We did not ignore States for

which we have no data, but accounted

for them by assigning regional

occurrence distributions to them. Our

data and methodology have been

approved by an independent expert peer

review panel. Our occurrence estimates

are close to those of the NAOS and

USGS.

Some commenters believe EPA’s

occurrence methodology is inconsistent

with the way compliance is determined

and that EPA should use a running

annual average for estimating

noncompliance.

We acknowledged in the proposed

rule (65 FR 38888 at 38907) that our

method of estimating occurrence is

different from the method used for

determining compliance with the MCL.

Our method usually gives higher

estimates, because we substitute nonzero values for non-detects, while under

the regulatory definition of compliance,

non-detects are assumed to equal zero.

We believe our method is the best one

despite the difference, for two reasons.

First, our goal is to characterize arsenic

occurrence as accurately as possible.

Given a sound characterization of

system-mean occurrence and of intrasystem and intra-source variability, the

numbers of systems and points of entry

expected to fail the regulatory definition

of compliance at some MCL option can

be determined. The reverse calculation,

on the other hand, is generally not

possible. Second, as analytical methods

improve and detection limits decrease,

the difference between the two methods

will decrease.

To the extent that our estimates

disagree with those used for

determining compliance, our estimates

will be higher and thus will cause us to

slightly overestimate the costs

associated with any MCL option. Our

estimates of benefits, on the other hand,

should not be biased one way or the

other by our occurrence estimate, since

health risks are mainly determined by

mean exposure over time, which we

accurately characterize. The same

would not be true if we used the

regulatory definition of non-detects,

which underestimates mean occurrence.

Commenters also pointed out that

occurrence estimates in different parts

of the rule and support documents are

inconsistent. Although the analysis is

internally consistent, apparent

inconsistencies in the numbers arise

from three sources: System versus site

considerations, year of the SDWIS

inventory, and use of best point or

regressed estimates. With respect to the

first point, because most large ground

water systems have multiple entry

points, some systems which have

average concentrations below the MCL

will still have impacted entry points. As

a consequence, the number of impacted

systems is much larger than the number

of systems with mean concentrations

above the MCL. In the proposal, this

difference amounted to several hundred

systems.

In connection with the second point,

year of the SDWIS inventory, it is not

unusual for there to be a change from

year to year in the inventory of

hundreds of water systems. This results

from restructuring and consolidations,

among other factors. In the final rule

and supporting documents, we have

tried to address this issue by

consistently using a single set of

baseline estimates, taken from EPA’s

Drinking Water Baseline Handbook

(EPA, 2000b). Regardless, this factor is

only responsible for a one or two

percent variation in the impact estimate,

and is not of sufficient significance to

impact the decision making process.

The third issue relates to the

representation of the mean system

arsenic occurrence. In many tables,

mean arsenic concentrations are

presented which reflect our best point

estimates. Nevertheless, the best

estimate of national cost impacts derives

from use of a best fit equation which

incorporates all of the data. We have

used these regressed fits in the

development of the costs and benefits.

The two sets of estimates are described

in section III.C.4.

3. Co-Occurrence

Some commenters believe EPA has

underestimated the co-occurrence of

arsenic with radon.We agree that, based

on the NWIS data, most systems with

arsenic greater than 10 μg/L will also

have radon greater than 300 pCi/L.

However, only about 8% of all systems

exceed both standards. Moreover, about

85% of such systems (again based on

NWIS) have radon in the range of 300

to 1000 pCi/L, where incidental removal

of radon will be most effective. We

expect, for example, that systems with

300 to 1000 pCi/L of radon will be more

likely to treat for arsenic by coagulation

and microfiltration, which removes

most radon incidentally by aeration.

Therefore, we believe that the impact of

co-occurrence of radon and arsenic will

be small.

Some commenters believed that EPA

did not evaluate the effect of different

sulfate levels in its decision tree. We did

evaluate several ranges of

concentrations of sulfate and arsenic

against each other (see 65 FR 38888 at

38938). The sulfate concentration ranges

included 0 to 25, 25 to 120, 120 to 250,

250 to 500, and >500 mg/L. The arsenic

concentration ranges included 0 to 2, 2

to 5, 5 to 10, 10 to 20, and >20 μg/L.

For these ranges, there was no apparent

change in co-occurrence of sulfate and

arsenic as the concentrations increased.

However, the Agency took the cooccurrence of arsenic and sulfate and

the impact on anion exchange

technology into consideration in the

decision tree at sulfate levels of <20, 20

to 90, 90 to 120, and >120 mg/L. The

revised decision tree for today’s final

rule only applies anion exchange when

sulfate levels are less than 50 mg/L.

Some commenters expressed their

belief that NWIS is inadequate to

estimate national co-occurrence of

arsenic and radon and that NWIS data

should be verified as representative of

PWS water use by requesting data from

States. It is true that NWIS includes

samples from non-drinking water

supplies. NWIS is, however, the largest

and best data base available for studying

co-occurrence with over 40,000 ambient

water samples. To the extent that nondrinking water samples affect our

estimates, they should cause us to

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7031

overestimate occurrence and therefore

also co-occurrence. We realize that

NWIS may not reflect conditions in any

given State or water system; we use it

only for deriving national estimates.

D. Analytical Methods

1. Analytical Interferences

Commenters expressed concern about

the potential for matrix interferences in

the analysis of arsenic at low levels. A

potential for chloride interference when

using ICP–MS with samples containing

high levels of chloride was specifically

noted by commenters. A commenter

also stated that some investigators had

reported arsenic results in drinking

water samples that differed depending

on the valence state of the arsenic in the

sample (i.e., As (III) or (V)) when using

methods that used GHAA technology.

The Agency agrees that interferences

may be encountered when determining

arsenic using the methods proposed in

the June 2000 rule (including the GHAA

technique). However, the Agency

disagrees that the interferences are

unexpected or impede compliance with

the arsenic MCL of 0.01 mg/L. Four

different measurement technologies are

approved for the analysis of arsenic: AA

furnace, AA-Platform, GHAA and ICP–

MS with respective MDLs of 0.001 mg/

L, 0.0005 mg/L, 0.001 mg/L, and 0.0014

mg/L. These technologies have been

used for compliance determinations of

arsenic for many years. The methods

written around each of these

technologies identify potential

interferences and contain corrective

procedures. In particular, the ICP–MS

method warns of potential interferences

from chloride and provides instructions

to eliminate this problem.

2. Demonstration of PQL (Includes

Acceptance Limits)

Several commenters agreed with the

±30% acceptance limit and the 0.003

mg/L PQL derived and proposed for

arsenic. Other commenters expressed

concerns that the PQL was not correctly

derived or that the acceptance limits

were too broad.

A commenter stated that the Agency

should set the PQL at 5 to 10 times the

method detection limits of 0.001mg/L

which would result in a PQL range of

0.005 to 0.010 mg/L. As previously

explained in section III.B.1 of this

preamble, EPA only uses the MDL

multiplier approach to derive a PQL

when there is insufficient

interlaboratory data to statistically

derive a PQL. For arsenic, the Agency

had ample WS data to derive a PQL

using the interlaboratory approach.

Several commenters were concerned

that the ‘‘PQL study is not realistic and

does not account for matrix interference

in real drinking water samples.’’ In

addition, some commenters stated that

the ‘‘PQL should be set at a level that

is achievable by laboratories on a

routine basis.’’ EPA disagrees that the

PQL for arsenic is unrealistic, or that it

has been set at a level that is

unachievable on a routine basis. As

explained in section III.B.1 of this

preamble, EPA used the interlaboratory

data from six recent WS studies to

derive the arsenic PQL. The WS studies

utilize reagent grade water (i.e., blank

water free of interferences) for the PEsamples that are analyzed in the WS

study. Use of reagent water to prepare

a test sample conforms with an accepted

and longstanding practice in which a

method developer validates an

analytical method in blank water before

looking for possible inaccuracies from

matrix effects when the method is

applied to a sample matrix (e.g., a

compliance drinking water sample).

Reagent water is used as an initial

benchmark for method development

and testing, because it is interferencefree and can be readily produced in any

competent laboratory. A lab

subsequently identifies and corrects for

matrix effects by comparing its

performance on reagent water to the

results on the matrix (contaminated

drinking water) or spiked matrix (clean

drinking water spiked with arsenic)

sample.

All of the methods approved for

SDWA and Clean Water Act (CWA)

compliance monitoring require that

laboratories demonstrate acceptable

performance in reagent grade water

before drinking water samples are

tested. A study conducted by Eaton

(Eaton, 1994) found that the type of

matrix and the analytical method used

had no significant effect on the

derivation of their PQL. This study

included drinking waters with high total

dissolved solids and total organic

carbon, and arsenic concentrations that

ranged from 0.001 to 0.010 mg/L. Thus,

EPA disagrees with the comment that

the PQL would be significantly different

if derived in various drinking waters

instead of in reagent water.

The Agency also believes that the

derived PQL of 0.003 mg/L is realistic

and is achievable on a routine basis. The

derivation of the PQL for arsenic is

consistent with the longstanding

process used to determine PQLs for

other metal contaminants regulated

under SDWA. In deriving the PQL for

arsenic, the Agency took into

consideration the issue of laboratory

capability, laboratory capacity, and the

ability of laboratories to achieve a

quantitation level on a routine basis.

The PQL for arsenic was derived from

data collected in WS studies in which

PE-samples were prepared with reagent

water spiked with low concentrations,

<0.006 mg/L, of arsenic. These studies

were conducted from 1992 to 1995. The

number of EPA Regional and State

laboratories that participated in each

study ranged from 26 to 45 laboratories.

Using acceptance limits of ±30% a

linear regression analysis of this data

yielded a PQL of 0.00258 mg/L. The

Agency rounded up to derive the

proposed PQL of 0.003 mg/L (3 μg/L)

with a ±30% acceptance limit. Over

75% of the EPA Regional and State

laboratories were able to report arsenic

concentrations within ±30% of 3 μg/L.

In addition, 62% of non-EPA

laboratories that participated in these

same WS studies were equally

successful. The number of non-EPA

laboratories in these WS studies ranged

from 360 to 619 laboratories, which

means that the number of laboratories

that successfully analyzed the low

concentration arsenic PE-samples

ranged from 223 to 384. This data

indicate that neither laboratory capacity

nor capability will be a problem at a

PQL of 3 μg/L ±30%. EPA, therefore,

believes that competent laboratories are

available, and with the use of the

quality control instructions in the

compliance methods will routinely

achieve this level of performance.

Several commenters felt the

acceptance limit of ±30% is too wide.

The ±30% acceptance limit was based

on a recommendation from the SAB.

The SAB recommendation was to

choose an acceptance limit similar to

that set for other regulated metals (EPA,

1995). These limits range from ±15% for

barium, beryllium, and chromium to

±30% for mercury and thallium

(§ 141.23(k)(3)). EPA chose the upper

(i.e., wider) limit on this range to ensure

that a sufficient number of laboratories

could be certified for arsenic

determinations (the number of

laboratories that can achieve the

accuracy acceptance limit increases as

the limit is widened). Several

commenters agreed with the proposed

±30% acceptance limit, because they

shared EPA concerns about insufficient

laboratory capacity if this limit was

narrowed.

3. Acidification of samples

A commenter stated that the Agency

needed to clarify that a sample can be

collected in the field without

acidification, and that acidification of

the sample can be done later at the

laboratory. The commenter believes that

delaying acidification does not affect the

compliance determination and that a

7032 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

laboratory is a better place in which to

handle acids. The Agency agrees with

this comment and had previously

clarified in a final rule (64 FR 67450;

December 1, 1999; see page 67452, item

11 and page 67456, item 3; EPA, 1999p),

that acidification of samples may be

conducted in the field or laboratory

with acidification at the laboratory

being the better and safer choice. In the

1999 rule, EPA noted that this change

would be affected by amending footnote

one to the table at § 141.23(k)(2) to read

as follows:

For cyanide determinations samples must

be adjusted with sodium hydroxide to pH >

12 at the time off collection. When chilling

is indicated the sample must be shipped and

stored at 4EC or less. Acidification of nitrate

or metals samples may be with a

concentrated acid or a dilute (50% by

volume) solution of the applicable

concentrated acid. Acidification of samples

for metals analysis is encouraged and

allowed at the laboratory rather than at the

time of sampling provided the shipping time

and other instructions in Section 8.3 of EPA

Methods 200.7 or 200.8 or 200.9 are

followed.

Although the June 2000 proposal

inadvertently omitted this footnote,

today’s final rule contains the correct

footnote.

Another commenter believed that

because the proposed sample

preservation requirement for arsenic

was new and supposedly untested, data

collected under the previous

requirements might not be comparable

to data resulting from the new sample

preservation requirement. These are not

new analytical requirements. The

commenter may have been misled by

the statement in the preamble to the

June 2000 arsenic proposal that EPA

proposed to add a ‘‘new’’ requirement to

the preservation and holding time table

at § 141.23(k)(2). It is only new in the

sense that EPA has codified the

requirements in today’s rule. Arsenic

compliance data collected in the past

and the arsenic data discussed in the

June 2000 proposal were collected using

these preservation and holding time

conditions.

E. Monitoring and Reporting

Requirements

1. Compliance Determinations

Most of the comments regarding

compliance determinations requested

the Agency to provide further

clarification on this issue. Many

commenters specifically asked EPA to

specify whether samples collected

quarterly as a result of an MCL violation

are defined as compliance samples or

confirmation samples. In today’s final

rule, the Agency has provided further

clarification in the regulatory language

to eliminate any misinterpretation.

The Agency defines quarterly samples

as compliance samples that must be

used to determine compliance.

Confirmation samples are any samples

that the State requires that go beyond

the minimum Federally required

samples defined in the following

paragraph.

Systems will determine compliance

based on the compliance samples

obtained at each sampling point. If any

sampling point is in violation of an

MCL, the system has a MCL violation.

For systems monitoring more than once

per year, compliance with the MCL is

determined by a running annual average

at each sampling point. Systems

monitoring annually or less frequently

whose sample result exceeds the MCL

for inorganic contaminants in

§ 141.23(c), or whose sample result

exceeds the trigger level for organic

contaminants listed in §§ 141.24(f) or

141.24(h) must revert to quarterly

sampling in the next quarter. The

system will not be considered in

violation of the MCL until it has

completed one year of quarterly

compliance sampling. If any sample

result will cause the running annual

average to exceed the MCL at any

sample point (i.e., the analytical result

is greater than four times the MCL), the

system is out of compliance with the

MCL immediately. Systems may not

monitor more frequently than specified

by the State to determine compliance

unless it has applied to and obtained

approval from the State. If a system does

not collect all required samples when

compliance is based on a running

annual average of quarterly samples,

compliance will be based on the

running annual average of the samples

collected. If a sample result is less than

the detection limit, zero will be used to

calculate the annual average. States

have the discretion to delete results of

obvious sampling or analytic errors.

States still have the flexibility to

require confirmation samples for

positive or negative results. States may

require more than one confirmation

sample to determine the average

exposure over a 3-month period.

Confirmation samples must be averaged

with the original analytical result to

calculate an average over the 3-month

period. The 3-month average must be

used as one of the quarterly

concentrations for determining the

running annual average. The running

annual average must be used for

compliance determinations.

Some commenters requested rule

language that clearly specifies how to

determine compliance and others

requested approval of scientific

methodologies that more accurately

reflect the average annual contaminant

exposure. Today’s rule requires that

monitoring be conducted at all entry

points to the distribution system.

However, the State has discretion to

require monitoring and determine

compliance based on a case-by-case

analysis of individual drinking water

systems.

The Agency cannot in this rule

address all of the possible outcomes that

may occur at a particular water system;

therefore, EPA encourages drinking

water systems to inform State regulators

of their individual circumstances. Some

systems have implemented elaborate

plans including targeted, increased

monitoring that is much more

representative of the average annual

mean contaminant concentration to

which individuals are being exposed.

(Some States determine compliance

based on a time or flow weighted

average.) In many cases, the State can

demonstrate that compliance is being

calculated based on scientific methods

that are more representative of the true

contaminant concentration that

individuals are being exposed to over a

year, but it substantially increases the

sampling and analytical costs.

Some States require that systems

collect samples from wells that only

operate for 1 month out of the year

regardless of whether they are operating

during scheduled sampling times. The

State may determine compliance based

on several factors including, but not

limited to, the quantity of water

supplied by a source, the duration of

service of the source, and contaminant

concentration.

2. Monitoring of POU Devices

Several commenters indicated that

there will be many implementation

problems with POU devices. EPA agrees

that some issues such as scheduling and

access for routine maintenance of POU

devices, liability, and monitoring may

be difficult but believes they can be

alleviated with sufficient planning. The

Agency will be providing POU

operation and maintenance guidance for

small systems after publication of the

final rule. In general, EPA believes that

POU systems can be easily installed,

maintained, and monitored for removal

efficacy.

EPA believes that it is feasible for

public water systems to own, control,

and maintain POE/POU devices for

arsenic MCL compliance either directly

or through a contract with a qualified

party. This approach, however, requires

more recordkeeping to monitor

individual devices than does centralized

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7033

treatment. Both POU AA and RO can be

obtained with mechanical warnings to

ensure that customers are notified of

operational problems. In the case of

activated alumina, such warnings

include shut-off valves that are triggered

prior to the adsorptive capacity of the

media being exhausted, based on the

volume of water treated. Reverse

osmosis POU devices come with total

dissolved solids detectors that activate

warning lights when membrane

integrity is compromised.

Systems having high arsenic

concentrations in the finished water that

choose to achieve compliance using

POU treatment would shift from

monitoring at a central location to

monitoring at the POU devices. As is the

case with any system that installs

treatment to lower contaminant

concentrations to levels below the MCL,

the monitoring frequency is part of the

compliance agreement between the

Primacy Agency and the system. The

compliance agreement must require

monitoring that is as protective as

monitoring for systems using

centralized treatment and may not be

less frequent than the routine

monitoring required in today’s rule (i.e.,

annual samples for surface water

systems and one sample every three

years for ground water systems). The

Primacy Agency will be responsible for

negotiating the monitoring schedule

with the system for POU devices and

may amend the compliance agreement

with the system to increase or reduce

the monitoring frequency to an alternate

schedule depending upon maintenance,

public responses, the implementation of

the service agreement, and the initial

monitoring results. For purposes of

forecasting national compliance costs,

EPA assumed that all POU devices

would be monitored for arsenic with

one sample taken the first year

following installation, samples taken

annually in subsequent years, and

replacement of the filter cartridge at

each POU site every 6 months.

3. Monitoring and Reporting for

NTNCWSs

Most commenters disagreed with

EPA’s approach of requiring NTNCWSs

to monitor and provide public

notification. Instead, the majority of

commenters indicated that EPA should

either require full coverage or not

regulate NTNCWSs. In today’s rule

making, EPA is requiring NTNCWSs to

comply with the arsenic regulation,

including the monitoring and reporting

requirements associated with arsenic in

§ 141.23, the MCL listed in § 141.62, and

the public notification requirements

(NTNCWSs are subject to the same

requirements as those of CWSs). EPA

acknowledges that there is uncertainty

associated with its information about

exposure patterns for consumers of

water from NTNCWSs and the

demographics of these facilities. Thus,

our understanding of the health risks to

consumers of water from NTNCWSs is

uncertain. In the case of arsenic,

however, EPA believes the additional

uncertainty in the overall risk analysis

supports the decision to treat these

facilities the same as CWSs. EPA also

believes the decision to cover these

facilities is underscored by

consideration of the risks to children

who consume water at day care facilities

or schools that are served by NTNCWSs.

4. CCR Health Language and Reporting

Date

Comments received on EPA’s

proposed consumer confidence

reporting (CCR) requirements were

equally split. Some commenters

supported EPA’s proposal to include

health effects language in CCRs if a

system detects arsenic above the revised

MCL prior to the effective date. Others

disagreed with the proposal because

they believed providing this information

prior to the effective date would be

confusing to consumers and would not

allow sufficient time to inform

consumers about the risks associated

with arsenic. These dissenting

commenters generally felt that it would

be more useful for systems to provide

notice to consumers that the MCL has

been revised and systems will be

required to comply by the effective date

of the revision.

The Agency believes that it is

important to provide customers with the

most current understanding of the risk

presented by arsenic as soon as possible

after establishing the new standard. In

today’s rule, community water systems

that detect arsenic between the revised

and existing MCL must include health

effects language in their consumer

confidence reports prior to the effective

date of the revised MCL. The Agency

does not believe that inclusion of this

information will be unnecessarily

confusing to consumers because, under

the CCR rule systems have the flexibility

to place this information in context.

EPA expects that affected systems will

include not only the health effects

language but also an explanation that

the current MCL has been revised and

the system is not in violation because

the new standard has not yet taken

effect.

EPA is finalizing an MCL somewhat

higher than the technologically feasible

MCL. Since some commenters

expressed concern about the risk that a

higher-than-feasible MCL might present

to certain consumers, EPA is requiring

systems that detect arsenic at

concentrations greater than 5 μg/L and

up to and including 10 μg/L to provide

additional information to their

customers. EPA believes that consumers

should be aware of the uncertainties

surrounding the risks presented by very

low levels of arsenic. While EPA

addressed many of the sources of

uncertainty in its risk analysis of arsenic

in support of the final rule, several

sources of uncertainty remain and will

be considered in the future in the

context of the periodic review and

revision, if appropriate, of drinking

water regulations as required by section

1412(b)(9) of SDWA.

5. Implementation Guidance

EPA appreciates the fact that the final

rule will place a new implementation

burden on many water systems,

particularly small systems. This is

particularly true of small ground water

systems that heretofore have not been

obliged to install, operate, and maintain

a treatment facility. EPA also

understands that new or more

sophisticated treatment technologies

will have obvious implications in terms

of operator capacity. EPA has addressed

this issue in several ways, and does not

believe that it is an impediment to

promulgating this new MCL. In brief,

some of the ways these implementation

concerns have been addressed are as

follows. EPA has identified a number of

affordable small system treatment

technologies that are based on

consideration of the capabilities of small

system operators. Systems will have the

latitude to choose the type of treatment

technology that is most cost effective

and appropriate (from an operation and

maintenance standpoint) for their

particular situation. EPA also plans to

publish implementation guidance for

small systems within 60 days of

publication of the final rule that will

provide helpful information to aid small

systems in both selecting and operating

small treatment technologies. EPA has

exercised its statutory authority under

section 1412(b)(10) of SDWA to provide

an additional 2 years for small systems

to comply with this rule (for a total of

5 years). Individual small systems may

apply for exemptions with extensions

that can provide for a total of an

additional 9 years to comply with the

requirements of this rule. Finally, EPA

notes that the final rule provides more

‘‘buffer’’ between the feasible level (3

μg/L) and the MCL of 10 μg/L as

compared to the proposed level of 5 μg/

L. Thus, treatment facilities that

experience operation difficulties would

7034 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

have more latitude in terms of the

timing and type of corrective measures

that would need to be taken than would

be the case with a more stringent final

MCL. For all of the above reasons, EPA

does not believe that there are any

insurmountable implementation

problems associated with the final MCL

for arsenic.

6. Rounding Analytical Results

Today’s rule requires that data be

reported to the nearest 0.001 mg/L (3

significant figures). Some commenters

felt that the rounding approach

described in the proposed rule would

significantly impact State programs. The

proposed rule solicited comment on an

approach requiring all values greater

than or equal to 6 to be rounded up and

all values less than or equal to 4 to be

rounded down (i.e. a value of 0.0056

mg/L would be rounded to 0.006 mg/L).

Results ending in 5 would round the

third significant digit to the closest

‘‘even’’ number. Therefore, a result of

0.0155 mg/L would be rounded to 0.016

mg/L, and 0.0145 mg/L would be

rounded to 0.014 mg/L. Some

commenters supported EPA’s rounding

approach. Other commenters indicated

that implementing this revision would

affect State data management operations

and would require staff training.

The Agency recognizes that

implementing a revision to the existing

rounding guidance may impact State

database and computer programs. In

today’s final rule, the Agency is

encouraging States to continue using the

rounding scheme that EPA

recommended in the ‘‘Water Supply

Guidance #72’’, dated April 6, 1981.

EPA stated in this guidance that:

All MCLs contained in the National Interim

Primary Drinking Water Regulations are

expressed in the number of significant digits

permitted by the precision and accuracy of

the specified analytical procedures. Data

reported to the State or EPA should be in a

form containing the same number of

significant digits as the MCL. In calculating

data for compliance purposes, it is necessary

to round-off by dropping the digits that are

not significant. The last significant digit

should be increased by one unit if the digit

dropped is 5, 6, 7, 8, or 9. If the digit is 0,

1, 2, 3, or 4 do not alter the preceding

number.

For example, analytical results for

arsenic of 0.0105 mg/L would round off

to 0.011 mg/L while a result of 0.0104

mg/L would round off to 0.010 mg/L.

F. Treatment Technologies

1. Demonstration of Technology

Performance

Many comments on the proposed

arsenic rule (EPA, 2000i) expressed the

concern that the treatment options that

EPA designated as BAT for compliance

with the arsenic MCL have not been

adequately demonstrated in full-scale

operation for arsenic removal.

Commenters noted that there are

relatively few arsenic treatment

facilities in the U.S., and these facilities

are generally small and were designed

for an arsenic MCL of 50 μg/L. Although

many of the treatment options

designated as BAT are widely used for

other water treatment objectives,

commenters stated that the limited

application of these technologies to

arsenic removal, especially in large

plants, creates uncertainty as to their

efficacy and feasibility for this purpose.

Commenters alleged that this situation

makes it difficult for water systems to

determine appropriate compliance

technology choices and raises questions

regarding the validity of EPA’s estimates

of costs for compliance with the arsenic

MCL.

EPA notes that SDWA section 1412(b)(4)(E)

states: [E]ach national primary drinking

water regulation which establishes a

maximum contaminant level shall list the

technology, treatment technique, and other

means which the Administrator finds to be

feasible for purposes of meeting such

maximum contaminant level.

SDWA defines feasible in section

1412(b)(4)(D) as follows:

For the purposes of this subsection, the

term ‘‘feasible’’ means feasible with the use

of the best technology, treatment techniques,

and other means which the Administrator

finds, after examination for efficacy under

field conditions and not solely under

laboratory conditions, are available (taking

cost into consideration).

Thus, SDWA requires EPA to list

feasible compliance treatment options

based on demonstration of efficacy

under field conditions and taking cost

into consideration.

For compliance with the arsenic MCL,

EPA judged technologies to be a best

available technology when the following

criteria were satisfactorily met:

• The capability of a high removal

efficiency;

• A history of full scale operation;

• General geographic applicability;

• Reasonable cost;

• Reasonable service life;

• Compatible with other water

treatment processes; and

• The ability to bring all of the water

in a system into compliance.

After reviewing a number of

technologies, EPA identified the

following as BAT for arsenic removal:

ion exchange, activated alumina, reverse

osmosis, modified coagulation/

filtration, modified lime softening,

electrodialysis reversal, and oxidation/

filtration. EPA believes that all of these

treatment options meet the SDWA

criteria of demonstrated efficacy under

field conditions and, further, meet the

additional criteria listed above which

EPA has historically used to identify

BAT. Studies which support this

assessment are described in

‘‘Technologies and Costs for Removal of

Arsenic from Drinking Water’’ (EPA,

2000t). Consequently, identification of

these technologies as BAT is

appropriate.

EPA recognizes that application of the

arsenic BAT treatment options to fullscale plants where they are optimized

specifically for arsenic removal is

limited. This is especially true in regard

to large plants. Nevertheless, as stated

previously, it is appropriate for EPA to

identify these technologies as BAT

because they have been demonstrated to

be effective for arsenic removal under

field conditions. Moreover, all of the

technologies listed as BAT have an

established history of successful

application at full scale in water

treatment plants for related treatment

objectives, specifically including the

removal of inorganic contaminants

(EPA, 2000t). Ion exchange is applied in

both municipal and POE/POU treatment

for softening (i.e., removal of calcium

and magnesium), as well as for removal

of nitrate, arsenic, chromium, radium,

uranium, and selenium. Activated

alumina is used in water treatment

plants to remove contaminants such as

fluoride, arsenic, selenium, silica, and

natural organic matter. Reverse osmosis

has traditionally been employed to

desalinate brackish water and sea water.

Electrodialysis reversal systems are

often used in treating brackish water to

make it suitable for drinking, and have

also been applied for wastewater

recovery. Oxidation followed by

filtration is utilized extensively in

public water systems for removal of iron

and manganese. Lime softening is

widely applied for reducing calcium,

magnesium, and other metals in large

water treatment systems. Most surface

water systems use coagulation/filtration

processes for particulate removal, and a

growing number of systems have

modified these processes to increase

removal of dissolved constituents,

primarily TOC and certain metals.

EPA believes that the successful

application of the arsenic BAT

treatment options for the removal of

contaminants other than arsenic is

relevant to their ability to remove

arsenic in full-scale plants. The physical

and chemical mechanisms operative in

these technologies for the removal of

hardness, sodium, fluoride, TOC and

other dissolved species are analogous to

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7035

the mechanisms by which these

technologies remove arsenic. In

addition, none of these technologies

have characteristics that would make

them ineffective or infeasible at large

scale or under long-term operation. The

specific conditions under which

optimized performance is achieved may

differ somewhat between removal of

arsenic and removal of other

contaminants, just as they may differ

from plant to plant based on water

matrix and other treatment processes in

use. However, because it has been

shown that these technologies can

remove arsenic under field conditions,

and because these technologies have an

established history of use for the

removal of inorganic contaminants in

full-scale systems, EPA believes it is

appropriate and technically justified to

conclude that they can be successfully

used for arsenic removal in full-scale

plants.

2. Barriers to Technology Application

EPA received many comments on the

proposed arsenic rule (EPA, 2000i) that

described challenges that systems

would face in applying the technologies

identified by EPA for compliance with

the arsenic MCL. Among such

challenges asserted by comments were

the following: the cost and availability

of adequately trained, certified

operators, especially in small systems;

hazards associated with the shipping,

handling, and storage of chemicals,

especially in regard to wells located in

residential areas; and the infeasibility of

water loss from treatment processes in

arid regions. Note that comments

dealing with residuals handling and

disposal are addressed subsequently in

section V.F.4 of this preamble.

In regard to water treatment plant

operators, EPA believes that operator

competency is critical for the protection

of public health and the maintenance of

safe, optimal, and reliable performance

of water treatment and distribution

facilities. Pursuant to SDWA section

1419(a), EPA has developed guidelines

for the certification and recertification

of the operators of community and

nontransient noncommunity public

water systems. These guidelines require

that all operating personnel who make

process control/system integrity

decisions about water quality or

quantity that affect public health must

be properly certified by the State. EPA

recognizes and has considered that the

treatment technologies, which systems

will install to comply with the arsenic

MCL, may add complexity to existing

treatment works or may be applied to

previously untreated ground water.

These situations will necessitate

additional operator training to ensure

that treatment processes are properly

operated, and systems will incur

additional costs associated with

operator labor.

EPA believes there will be sufficient

numbers of adequately trained and

certified operators available to public

water systems. Operator training

programs are available throughout the

U.S. through home study courses,

classroom settings, and in-plant

training. Current and new water

treatment operators can obtain the

training necessary to operate any of the

treatment technologies considered for

compliance with the arsenic MCL. EPA

is developing a grants program pursuant

to SDWA section 1419(d) to reimburse

training and certification costs for

operators employed by community

water systems and nontransient,

noncommunity water systems serving

3,300 or fewer people. This funding will

reduce the compliance burden on these

small systems, thereby increasing the

likelihood that the systems will be able

to reliably operate and maintain new

treatment. Today’s rule offers five years

between promulgation and the time

systems must be in compliance. An

exemption can provide three additional

years to achieve compliance, and this

exemption may be renewed for up to six

years for small systems. The Agency

believes this amount of time will offer

ample opportunity for States’ operator

training and certification programs to

prepare operators.

EPA’s Operator Certification

Guidelines require that a certified

operator be responsible, in charge, and

available to all community and

nontransient, noncommunity water

systems. However, this does not mean a

certified operator must be on site at

every treatment facility 24 hours a day,

7 days a week. The treatment

technologies do not necessarily require

constant supervision of operators.

Depending upon State requirements,

regional certified operators could travel

from facility to facility on a regular basis

to oversee the efforts of the non-certified

operators provided the certified operator

was also available to the system on an

on-call basis. Systems must consider

their operational constraints in selecting

treatment technologies and in

establishing appropriate operational

controls.

EPA has accounted for additional

labor costs associated with the operation

of treatment technologies for

compliance with the arsenic MCL. The

Agency’s analyses of additional costs

are described in ‘‘Technologies and

Costs for Removal of Arsenic from

Drinking Water’’ (EPA, 2000t). The labor

rates used to develop operation and

maintenance costs are conservative

estimates based on loaded rates for

certified operators in large and small

systems.

Concerns expressed by commenters

on the storage, handling, and

application of chemicals used in arsenic

treatment centered on hazards to the

public health and safety if an accidental

release occurred. These comments

hinged on the fact that ground water

systems may have wells located in

residential and high population-density

areas. Several commenters asserted that

the risks from chemical application in

these areas may outweigh the hazards

associated with potentially elevated

arsenic concentrations. Among the

chemicals of concern are chlorine for

pre-oxidation, and acids and bases for

pH adjustment.

While EPA understands the nature of

this concern, EPA does not believe that

chemical usage for compliance with the

arsenic MCL poses a significant risk.

Systems using chemicals should employ

established safety and emergency

response procedures, along with

effective operator training and

certification. Measures that can be taken

to alleviate potential problems with

chemical handling and storage include:

review chemical documentation to

check quantity and quality; visually

inspect chemicals and conduct

appropriate verification tests; label and

secure unloading points; verify adequate

receiving tank capacity; inspect

chemical containers for any damage or

evidence of leaks; specify delivery at

scheduled times; specify equipment

necessary for safe handling and transfer

of chemicals; and supervise unloading

with trained personnel (Casale and

LeChevallier, 2000).

Many community water systems

currently disinfect with chlorine. This

includes many small systems and

ground water systems with wells in

residential areas. Small systems and

ground water systems typically apply

chlorine as hypochlorite that carries

relatively little risk. Liquified chlorine

gas is generally cheaper and is used by

many large systems. The use of chlorine

gas involves certain risks associated

with accidental leakage. However, these

risks are well understood and are

managed through high standards of

equipment specification, operation and

management procedures, and training of

personnel (Porter et al., 2000).

Systems using activated alumina may

lower the pH of the feedwater in order

to increase process efficiency, and

subsequently raise the pH to stabilize

the water. EPA believes that most large

systems have a sufficient level of

7036 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

technical expertise to modify pH

without difficulty. However, EPA

recognizes that very small systems may

lack the operator capacity to

successfully rely on pH modification as

a component of a treatment process. In

estimating costs for compliance with the

arsenic MCL, EPA assumed that most

very small systems using activated

alumina would not adjust the raw water

pH. These plants would run under lessthan-optimal conditions but would still

meet the arsenic MCL. Furthermore, for

small systems and for other systems that

may lack the technical expertise to

adjust pH, other treatment options are

available. Because of the number and

flexibility of treatment options available

to systems, along with the training and

certification of operators, EPA believes

that hazards to the public as a result of

arsenic treatment will be minimal.

In regard to concerns with water

scarcity, EPA notes that of the

technologies listed in the proposed rule

as BAT, only reverse osmosis (RO) and

electrodialysis reversal (EDR) produce

reject water in a quantity likely to make

them undesirable in arid regions. While

EDR and RO were listed as BAT in the

proposed rule, they were not used in the

final national cost estimate because

other options are more cost effective and

do not reject a large volume of water

like these two technologies. Thus, we

did not assume that any systems would

chose EDR and assumed that RO would

only be used by a small fraction of small

systems and only in POU devices. POU

devices treat only a small fraction of the

household water, so that any water loss

is minimized. Consequently, EPA does

not believe that commenters’ concerns

about water scarcity alter EPA’s

projections of systems’ ability to comply

with the arsenic MCL. Moreover, in

today’s rule EPA has established the

MCL for arsenic at 10 ppb. At this level,

it would be possible for many systems

to use RO or EDR in a split-stream

mode, treating a portion of the water,

and blending treated and untreated

water to achieve compliance. This

option would enable systems to

significantly reduce the amount of reject

water produced were they to select

these technologies.

In cases where the available water

resources are limited, systems may

select technologies like activated

alumina, anion exchange, and

coagulation assisted microfiltration

where water loss is limited to a few

percent or less. As discussed in

‘‘Technologies and Costs for Removal of

Arsenic from Drinking Water’’ (EPA,

2000t), the principal water losses

associated with anion exchange and

activated alumina result from the

rinsing of the beds after regeneration

and, in some limited cases, backwashing

for removal of solids. In normal

operating conditions, EPA expects this

waste water to amount to a small

percentage of the total water produced.

3. Small System Technology

Application

A number of commenters raised

concerns over the small system

compliance technologies described in

the proposal. Many of these comments

questioned the ability of small systems

to apply these technologies. EPA has

carefully considered these comments

and responses to the significant issues

are provided below (see section I.G. for

a discussion of the affordable small

system compliance technologies under

today’s final rule).

The most significant issues raised by

comments addressed the application of

Point-of-Use/Point-of-Entry (POU/POE)

treatment in small systems. Comments

cited requirements for preoxidation for

activated alumina (AA) units as reasons

why the POU/POE devices would not be

desirable. EPA notes that many small

systems have disinfection treatment

systems in place that could act as

preoxidation for POE/POU units.

Comments also raised concerns

regarding the brine or concentrate

stream generated by reverse osmosis

(RO) POU/POE units. Commenters

questioned whether the systems would

waste precious water in arid areas. EPA

believes systems in arid areas are more

likely to select activated alumina (AA)

or another centralized treatment

technology. Commenters also raised

concern over the disposal of the

concentrate from these units into sewer

or septic systems. In response, EPA

believes it would be highly unlikely for

the concentrate stream to pose problems

because only about 1% of the household

water is treated, thereby minimally

influencing the quality of the sewage

discharged from the household. Finally,

commenters questioned the ability of

small systems to maintain POE/POU

devices which are installed in private

homes. EPA believes it is feasible for

public water systems to own, control,

and maintain POE/POU devices for

arsenic MCL compliance either directly

or through a contract with a qualified

party. While EPA recognizes that access

to homes for maintenance may be an

issue for some systems, we believe that

such access would be permitted in

others, especially if significant cost

savings could be achieved.

4. Waste Generation and Disposal

Many comments stated that EPA did

not adequately consider problems with

waste generation and disposal when

evaluating which technologies would be

most appropriately used for achieving

compliance. Commenters expressed

particular concern with anion exchange,

activated alumina, and reverse osmosis

because wastes generated from these

processes, depending upon their

operating and site specific conditions,

could be hazardous or difficult to

dispose of. Comments indicated that

many utilities would have difficulty in

achieving compliance with the

proposed rule while also maintaining

compliance with other environmental

laws and regulations (e.g., RCRA and

CWA). Commenters questioned EPA’s

analysis for the proposed rule that

indicated that no RCRA hazardous

wastes would need to be disposed in the

decision tree.

Arsenic treatment technologies

produce three different types of wastes:

Brines, sludges and spent media.

Depending upon arsenic concentration

and the characteristics of the waste,

each of these wastes can pose disposal

challenges and has the potential for

being classified as hazardous.

Arsenic wastes are defined as

hazardous if their toxicity characteristic

(TC) exceeds 5 mg/l of arsenic. The

Toxicity Characteristic Leaching

Procedure (TCLP) is a method by which

waste is evaluated to determine if it

exceeds the TC. If waste is < 0.5% dryweight solids, then the liquid is defined

as the TCLP extract and concentrations

in it are compared against the TC level

to determine if it is hazardous. If the

waste is ≥ 0.5 % dry-weight solids, then

a TCLP that conservatively simulates

leaching from a landfill is used to

determine if the TC level would be

exceeded. EPA considered TC and TCLP

results from residuals produced by the

treatment technologies under

consideration and selected only those

technologies that would not produce a

hazardous waste.

Upon the review of public comments

and further analysis, EPA agrees with

comments that some of the treatment

train technologies in the decision tree of

the proposed rule could have created

hazardous wastes under certain

operational circumstances. Thus, EPA

has narrowed its selection of available

technologies in the decision tree for the

final rule as indicated in Table V.F–4.1.

EPA believes that the treatment options

included in Table V.F–4.1 can address

all treatment challenges without

creating hazardous wastes, while being

able to achieve compliance with the

final rule. EPA has revised its national

costs upward to reflect the changes in

the decision tree. These costs are

described in more detail in this

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7037

preamble and in support documents for

this rule (EPA, 2000o and EPA, 2000t).

More specific rationale for the

changes in the treatment train

technologies considered in the decision

tree are discussed in the following

paragraphs and in the ‘‘Technology and

Cost Document’’ (EPA, 2000t).

a. Anion exchange. When anion

exchange resins are cleaned, they create

a regeneration brine. Influent sulfate

and arsenic concentrations, regeneration

level, and rinse volume influence the

resultant brine concentration levels of

arsenic. EPA conducted modeling to

determine the feasible operating

conditions and source water arsenic and

sulfate concentrations under which

anion exchange could effectively

remove arsenic without creating an

arsenic brine that exceeded an arsenic

concentration of 5 mg/L. Based on this

analysis (EPA, 2000t), EPA determined

brine arsenic concentrations could

exceed 5 mg/L when: (a) Arsenic

influent levels exceed 15 μg/L and

sulfate concentrations exceed 25 mg/L,

and (b) when arsenic influent levels

exceed 25 μg/L and sulfate

concentrations ranged between 25 and

90 mg/L. Based on this analysis, EPA

eliminated landfills and evaporation

ponds from the final decision tree for

the conditions indicated in Table V.F–

4.1.

As part of its proposed and final

decision tree evaluation, EPA assumed

that brine streams with < 0.5% solids

could potentially be disposed of through

domestic sewage or mixtures of

domestic sewage to POTWs regardless

of the TC, since this is excluded from

regulation under RCRA. Piping the brine

directly to the POTW without passing

through the sewer system does not meet

the exclusion, nor does trucking the

brine to the POTW. Even though brine

disposal via sewage to POTWs is not

restricted by RCRA, EPA recognizes that

brine disposal can be restricted by the

POTW’s pretreatment programs. POTWs

may establish Technically Based Local

Limits (TBLLs) for arsenic to control:

arsenic concentrations in POTW

biosolids, arsenic concentration in the

POTW discharge, or total dissolved

solids (TDS) in the POTW discharge.

Many comments indicated that

significant increases in total dissolved

solids would make brine disposal to a

POTW unacceptable, especially in the

Southwest where water resources are

scarce. Even under the lowest

regeneration level of 5.1 lb/ft3 assumed

in EPA’s analysis, TDS increases would

likely be prohibited by POTWs when

influent sulfate concentrations exceed

90 mg/L, and limited to POTWs where

brine volume is very small compared to

total volume for sulfate concentrations

between 25 and 90 mg/L. Therefore, as

described in section I.F., EPA modified

the compliance decision tree to assume

systems with sulfate concentrations

greater than 50 mg/L would not select

anion exchange as a treatment

technology. In its final decision tree,

EPA assumed that drinking water plants

with sulfate concentrations of less than

20 mg/l and with a regeneration

frequency of 1500 bed volumes, or with

sulfate concentrations between 20 and

50 mg/l and a regeneration frequency of

700 bed volumes, might use anion

exchange with waste disposal via

sewage to POTWs and be able to comply

with local TBLLs. In the final decision

tree less than 10% of the systems are

assumed to use anion exchange versus

over 50% of the systems being assumed

to use this technology under the

proposal.

b. Activated alumina. The proposed

rule considered activated alumina with

regeneration and listed discharge to a

sanitary sewer as the disposal

mechanism for the brines. Many

comments on the proposed rule noted

that TBLLs for arsenic or total dissolved

solids might restrict discharge of brine

streams to the sanitary sewer. Under

today’s final rule (see section I.F.),

regeneration of activated alumina media

is not recommended for a number of

reasons, including the difficulty of

disposing of the brines. In the final

decision tree, EPA assumes disposal of

spent AA media (either from central

treatment or POU) to landfills as the

waste disposal method for AA. EPA

believes that spent AA media will be

nonhazardous because the TCLP test is

conducted using weak acid at a pH of

5 which is near the optimal pH for

adsorption of arsenic onto AA (Kempic,

2000). Wang et al. (2000) evaluated AA

spent media from two small systems

having treating influent arsenic

concentrations of > 50 μg/l and found

TCLP with arsenic concentrations of

0.07 mg/L or less, well below the TCLP

limit of 5 mg/L. Some public comments

indicated concern that the TCLP test

conditions at the pH of 5 may not reflect

conditions at landfills which may have

higher pHs. In response, EPA notes that

the TCLP is the defining test specified

in 40 CFR 261.24 for determining

whether a waste is TC hazardous, and

it applies regardless of the actual

management of the waste unless some

exemption applies.

In the final decision tree, EPA has

revised the treatment train assumptions

for AA to be operated in series (i.e., two

treatment units in sequence rather than

as singular units as was considered

under the proposal) under various pH

conditions (see Table V.F–4.2).

Operation in series will allow longerrun times and more cost-efficient

disposal of spent media. The range of

pH conditions is assumed in

consideration of public comments that

some utilities will prefer to operate

without pH adjustment, thereby

minimizing oversight and the

‘‘footprint’’ of land needed for the

treatment facilities (since no additional

chemical feed or storage facilities are

needed). While pH adjustment to low

levels will optimize AA removal of

arsenic, this may not be an option for

certain facilities depending upon land

availability. Therefore, EPA considers a

wide range of pH conditions of AA in

the series mode.

c. Reverse osmosis. Except for POU

treatment, EPA did not use reverse

osmosis in the decision tree of either the

proposed or final rule (EPA, 2000h);

EPA, 2000o). The concentrate stream

from POU devices can be disposed of

through discharge into domestic

wastewater and thereby be exempt from

RCRA regulation. It would also be

highly unlikely for the concentrate

stream to pose problems with TBLLs

because only about 1% of the household

water is treated, thereby minimally

influencing the quality of the sewage

reaching the POTW. Therefore, the

decision tree to the final rule includes

POU reverse osmosis.

TABLE V.F–4.1.—TREATMENT TRAINS IN FINAL VERSUS PROPOSED ARSENIC RULE DECISION TREE

Treatment train: treatment & residuals management combination

National cost estimate assumes will be selected by

systems in Reason for change

Proposed rule Final rule

Regionalization ........................................................ NO ................................. NO ................................. N/A

Alternate Source ...................................................... NO ................................. NO ................................. N/A

Modify Lime Softening ............................................. YES ............................... YES ............................... N/A

7038 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

TABLE V.F–4.1.—TREATMENT TRAINS IN FINAL VERSUS PROPOSED ARSENIC RULE DECISION TREE—Continued

Treatment train: treatment & residuals management combination

National cost estimate assumes will be selected by

systems in Reason For Change

Proposed rule Final rule

Modify Coagulation/Filtration ................................... YES ............................... YES ............................... N/A

Anion Exchange (25 mg/L sulfate) & POTW discharge.YES ............................... YES ............................... Treatment name revised—Anion Exchange (<20 mg/L sulfate).

Anion Exchange (150 mg/L sulfate) & POTW discharge.NO ................................. NO ................................. N/A

Anion Exchange (25 mg/L sulfate) & Evaporation

Pond, Landfill.

YES ............................... NO ................................. Brine stream may be hazardous

waste. Commenter issue—EPA

evaluation.

Anion Exchange (150 mg/L sulfate) & Evaporation

Pond, Landfill.

NO ................................. NO ................................. N/A

Activated Alumina (16500 Bed Volumes) & Landfill YES ............................... REVISED ....................... Revised approach uses multiple columns in series operation.

Activated Alumina (3000 Bed Volumes) & Landfill NO ................................. NO ................................. N/A

Reverse Osmosis & direct discharge ...................... NO ................................. NO ................................. N/A

Reverse Osmosis & POTW discharge .................... NO ................................. NO ................................. N/A

Reverse Osmosis & Chemical Precipitation, Landfill.NO ................................. NO ................................. N/A

Coagulation Microfiltration & Mech. Dewatering,

Landfill.

YES ............................... YES ............................... N/A

Coagulation Microfiltration & Non-Mech.

Dewatering, Landfill.

YES ............................... YES ............................... N/A

Oxidation Filtration & POTW discharge .................. YES ............................... YES ............................... N/A

Anion Exchange (25 mg/L sulfate) & Chem Precipitation, Landfill.YES ............................... NO ................................. Brine stream may be hazardous

waste. Commenter issue—EPA

evaluation.

Anion Exchange (150 mg/L sulfate) & Chem Precipitation, Landfill.YES ............................... NO ................................. Brine stream may be hazardous

waste. Commenter issue—EPA

evaluation.

Activated Alumina (16500 BV) & POTW ................. NO ................................. NO ................................. N/A

Activated Alumina (3000 BV) & POTW ................... NO ................................. NO ................................. N/A

Anion Exchange (90 mg/L sulfate) & POTW .......... YES ............................... REVISED ....................... Lower sulfate concentration selected

to minimize total dissolved solids

increase. Commenter issue—EPA

evaluation.

Anion Exchange (90 mg/L sulfate) & Evaporation

Pond, Landfill.

YES ............................... NO ................................. Brine stream may be hazardous

waste. Commenter issue—EPA

evaluation.

Point-of-Entry Activated Alumina ............................. YES ............................... NO ................................. Run length only exceeds six months

when finished water pH <7.5

Point-of-Use Reverse Osmosis ............................... YES ............................... YES ............................... N/A

Point-of-Use Activated Alumina ............................... YES ............................... YES ............................... N/A

TABLE V.F–4.2.—NEW OR REVISED

TREATMENT TRAINS

Treatment Train Revision

Activated Alumina

(pH7-pH8) & Landfill.

Series Operation.

Activated Alumina

(pH8–8.3) & Landfill.

Series Operation.

Activated Alumina

(pH adjusted to

pH6—23,100 Bed

Volumes) & Landfill.

Series Operation.

Activated Alumina

(pH adjusted to

pH6—15,400 Bed

Volumes) & Landfill.

Series Operation.

Anion Exchange (20–

50 mg/L sulfate) &

POTW.

Use 700 Bed Volumes as Run

Length.

5. Emerging Technologies

A number of comments state that

several of the emerging technologies

discussed in the proposal (e.g., granular

ferric hydroxide, see section I.F) are

likely to be the most cost effective

treatment option for systems,

particularly small systems. These

comments state that systems may not

select these emerging technologies

because they have not been listed as

BAT. In response, EPA must clarify that

systems are not required to use BAT to

achieve compliance with the MCL. A

system may use any technology that is

accepted by the State primacy agency

provided the technology achieves

compliance with the MCL. However, if

a system is unable to meet the MCL with

its chosen technology, the system will

not be eligible for a variance unless the

installed technology is listed as BAT.

Other comments indicated that there

will not be sufficient time for further

testing of these emerging technologies

prior to the effective date of the MCL.

EPA notes that because of the capital

improvements required for compliance

with the MCL, the effective date of

today’s rule is 5 years from the date of

promulgation for all system sizes. This

should provide systems with adequate

time for testing of the emerging

technologies. Moreover, States may, as

described in section I.H, provide small

systems with up to an additional nine

years to comply through exemptions.

G. Costs

1. Disparity of Costs

Many public comments stated that

EPA substantially underestimated costs

for implementing the proposed rule.

Comments pertained to national cost or

regional cost estimates and system level

cost estimates. Commenters stated that

EPA’s national cost estimates were low

because: (a) The decision tree led to an

over selection of technologies with low

associated costs, and (b) the system

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7039

level costs associated with the selected

technologies were low. Elaboration of

public comment concerns and EPA’s

response in each of these categories

follows. Also, since many public

comments referred to the report ‘‘Cost

Implications of a Lower Arsenic MCL’’

(Frey et al., 2000) as a basis for their

comments, EPA analyzed the report in

detail. As noted below, the Agency

disagrees with the approach Frey et al.

(2000) used to produce the cost

estimates in this report.

a. What is EPA’s response to major

comments on the decision tree for the

proposed rule? Commenters indicated

that EPA’s decision tree did not

adequately recognize constraints in

technology selection including

feasibility of waste disposal, concerns

with compliance with other EPA

regulations (e.g., RCRA and CWA), land

availability, complexity of operation

and availability of skill level

(particularly for small systems), and

excess use of water in water scarce

areas. Particular concern was raised by

the extent to which EPA predicted that

anion exchange would be used given

concerns with sulfate and total

dissolved solids, chromatographic

peaking (possible rapid breakthrough of

arsenic at above influent concentration

levels due to competition from other

ions), and handling of regeneration

process streams and disposal of wastes

(some of which may be hazardous).

Commenters also suggested that EPA

over predicted the use of greensand

filtration since it only removes a limited

amount of arsenic at low iron

concentrations. Comments suggested

that EPA should consider much greater

use of activated alumina in the spent

media replacement mode with disposal

to landfills because of facility of

operation and low costs. Comments also

suggested use of reverse osmosis and

nano-filtration in areas unlikely to have

a water scarcity problem. Although

central treatment with reverse osmosis

was listed as one of the possible

compliance technologies under the

proposed rule, it was not used in the

EPA’s decision tree.

In preparing the cost estimate for the

proposed rule, EPA predicted

compliance outcomes by considering:

(1) Technologies already in place, (2)

feasibility of application of the

technology, and (3) least cost of

technology. Given all available

information at the time of proposal, EPA

developed its decision tree. EPA

received many informative comments

pertaining to the feasibility of various

treatment technologies considered. EPA

agrees with public comments that some

of the waste disposal options considered

with anion exchange under the

proposed rule could create hazardous

wastes (see V.F.4. of this preamble). To

address this concern EPA has

eliminated the following treatment

trains from its final decision tree: Anion

exchange with chemical precipitation

and disposal of waste to landfills, and

anion exchange with discharge to

evaporation ponds and disposal of

waste to landfills.

EPA agrees with public comments

that activated alumina is likely to be

used by many more systems than EPA

predicted in the proposal. In response to

comments, EPA revised the treatment

train assumptions for AA to be operated

in series under various pH conditions.

Operation in series will allow longer

run times and more cost-efficient

disposal of spent media. The range of

pH conditions is assumed in

consideration of public comments that

some utilities will prefer to operate

without pH adjustment, thereby

minimizing oversight and the

‘‘footprint’’ needed for the treatment

facilities. While pH adjustment to pH

6.0 will optimize AA removal of arsenic,

this may not be an option for certain

facilities depending upon available land

and expertise. Thus, EPA recognizes

higher operational costs for AA for a

substantial number of systems operating

at less than optimal pH.

Research (Subramanian et al., 1997)

indicates that oxidation filtration

(greensand filtration) achieved about

80% removal of arsenic when the iron

to arsenic ratio was 20:1 but less than

50% removal when the iron to arsenic

ratio was 7:1. In developing national

cost estimates, EPA assumed that

systems would opt for this type of

technology only if more than 300 μg/L

of iron was present in the source water

and no more than 50% arsenic removal

was needed to achieve the MCL. EPA

believes that its applicability

assumptions for greensand filtration are

conservative and therefore continues to

support its usage in the decision tree for

the final rule. Greensand filtration is a

relatively inexpensive technology that

may be appropriate for those systems

that do not require much arsenic

removal and have high iron in their

source water. However, in the decision

tree for the final rule, EPA lowered the

expected use of greensand filtration to

systems serving less than 3,300 (versus

in systems serving less than 10,000

under the proposed rule) and reduced

its usage by about 1⁄3 (EPA, 2000h; EPA,

2000h). This drop is mainly attributed

to the change in the MCL and fewer

systems having arsenic at levels

between 5 μg/L and 10 μg/L than

between 10 and 20 μg/L. The ranges 5–

10 μg/L and 10–20 μg/L reflect the

arsenic concentration ranges that

systems would have to fall within to be

able to consider greensand, if only 50%

removal efficiency is assumed.

EPA continues to believe that reverse

osmosis, while a very effective

technology for removing arsenic, is not

likely to be used as a centralized

treatment option (even in areas of ample

water supply) because of higher costs

relative to other treatment options. EPA

did not consider nanofiltration a likely

compliance technology because of high

costs relative to other technologies and

decreased removal efficiency when

operated to constrain production of

waste streams.

b. What is EPA’s response to

comments on system level costs? Under

the proposed rule EPA only included

activated alumina (AA) costs for small

systems. A number of comments

indicated that EPA should revise its

decision tree to include AA and

associated costs for all system sizes

because AA is more economical than

anion exchange. After considering the

information provided by these

comments, EPA expanded estimates of

the use of AA in the decision tree for the

final rule. EPA also revised its decision

tree and developed costs for four

different types of AA treatment for all

system sizes—two for unadjusted pH

and two where the pH has been adjusted

to the optimal pH of 6. (The effects of

these changes in the decision tree

analysis are described in section V.G.1).

The main change between the design

used for the proposed rule versus the

final rule is that smaller columns

containing the activated alumina are

operated in series rather than as a single

column. This will provide greater

utilization of the media before disposal

and is more consistent with the designs

used by commenters in evaluating

disposable activated alumina. EPA’s

new AA costs specify different unit cost

equations and flow boundary conditions

for small versus large systems. Also,

EPA has included new operating and

maintenance (O&M) costs for waste

disposal of spent AA media. The effect

of all these changes is, in general, to

decrease capital costs but to increase

O&M costs and to increase overall AA

system level costs within a particular

size category. Despite these increases in

costs for AA, AA is by far the most used

technology among ground water systems

in the final decision tree. The ‘‘Arsenic

Technologies and Costs’’ (T&C)

document (EPA, 2000t) for the final rule

describes in detail the basis for the unit

costs used for each of the new types of

AA treatment.

7040 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

Several comments indicated that

EPA’s cost estimates were calculated for

flow rates outside of their boundary

conditions and thus the accuracy of

many of the unit costs are in error. EPA

analyzed the data provided by these

comments and revised the cost

equations used to estimate unit costs for

the final rule. We modified cost

equations and flow boundary conditions

for AA, modified coagulation filtration,

modified lime softening, anion

exchange, coagulation microfiltration,

and POU treatment. Most of the unit

costs increased relative to those used for

the proposed rule. The T&C document

(EPA, 2000t) describes the basis for the

unit costs used for the final rule.

A number of comments stated that

EPA’s cost estimates should include

pre-oxidation costs with AA in ground

waters since many systems may not

already be disinfecting. EPA must

clarify that the cost estimates included

prechlorination costs for any system

that did not have existing disinfection

treatment. For ground water systems,

13% to 54% (depending upon system

size) of systems predicted to use AA

were assumed to add pre-oxidation.

Several comments indicated that

EPA’s cost estimates for the proposal

did not include corrosion control costs.

However, the corrosion control costs

were included as a component of the

unit costs for the following

technologies: modified lime softening,

modified coagulation filtration,

coagulation assisted microfiltration, and

activated alumina options operating at

the optimal pH. EPA believes that

through appropriate use of corrosion

control, systems will be able to comply

with the lead and copper rule and meet

the arsenic MCL.

c. What is EPA’s response to

comments that state the report ‘‘Cost

Implications of a Lower Arsenic MCL’’

(Frey et al., 2000), be used as a basis for

reflecting more realistic national costs

than EPA’s estimates? A number of

comments noted that the report ‘‘Cost

Implications of a Lower Arsenic MCL’’

(Frey et al., 2000), ‘‘the Cost

Implications Report,’’ or ‘‘the report,’’

provides best-case national estimated

annualized costs of $1,460 million at the

5 μg/L arsenic MCL option and $605

million at the 10 μg/L MCL option.

Many comments stated that EPA’s

national cost estimates were

unrealistically low based upon the Cost

Implications Report.

EPA appreciates the substantial level

of information available from the Cost

Implication Report in regard to

evaluation of technological feasibility

for arsenic removal. This report was one

of several sources that influenced EPA

to predict much less use of anion

exchange and much greater use of

activated alumina in the decision tree

for the final rule. However, EPA

believes that some parts of the report’s

analysis contributed to overestimating

national cost estimates. These issues

include differences in flow rate

assumptions, unit costs, and national

estimates for arsenic occurrence,

summarized below. A more detailed

analysis is available in EPA’s Response

to Comment Document for the final rule.

Flow rate assumptions. Flow rate

assumptions are used with engineering

cost models to estimate system level

treatment costs for various technologies

considered appropriate for achieving

compliance. If flow rates are

overestimated, system level treatment

and national costs will be

overestimated. EPA uses design flow

rates to estimate capital costs and

average flow rates to estimate

operational and maintenance costs.

The Cost Implications Report (Frey et

al., 2000) uses significantly higher flow

rates than EPA (EPA, 2000h; EPA,

2000o) for conducting national cost

impact analysis for alternative arsenic

MCLs. For most population categories of

systems ranging between 3301 and 1

million people, AWWARF used flow

rates that were 2–4 times higher than

EPA’s assumptions. Based on EPA’s

analysis of the Cost Implication Report

it appears that the report used more

system size categories than EPA and

transferred flow rates for larger-system

size categories into smaller-system size

categories. EPA believes that differences

in the flow rate assumptions would

produce an estimate of at least $400

million per year higher than an estimate

using EPA’s flow rates for the proposed

arsenic MCL option of 5 μg/L.

Since the release of the Cost

Implications Report, the authors revised

their analysis to include different flow

rates (Frey et al., October 2000), ‘‘the

Updated Cost Implications Report.’’ The

updated report based its new flow rates

on the equations provided in the

Proposed Arsenic in Drinking Water

Rule Regulatory Impact Analysis (EPA,

2000h). The flow rates for ground water

systems were based on the population/

flow equations for publicly owned

ground water systems and the authors

selected the midpoint in each

population category (e.g., using a flow of

systems serving 550,000 persons to

estimate costs for systems serving

between 100,000 and 1 million people).

In the Updated Cost Implications Report

the authors state that:

[T]he cost response to the difference in

flow rates is mixed due to the large flow

increases in the two largest population

categories (100,0000 to 1 million and > 1

million) versus the decreases in the other

flow categories (5,000 to 100,000).

EPA believes that the revised analysis

with the new flow rates in the Updated

Cost Implications Report still

overestimates costs. First, the revised

design and average flows are only larger

for ground water systems with

populations greater than 1 million

people. Second, estimating flow rates

for systems within a category using the

population midpoint assumptions in the

revised analysis continues to cause cost

overestimates because many more

systems in each population size

category occur in the lower part of the

range than the upper part of the range.

For example, EPA’s data indicate that,

in the flow category of ground water

systems serving 100,000 to 1 million

people, one-half of the systems have

populations under 173,000 people (EPA,

December 1997 Freeze of Safe Drinking

Water Information System) and that the

mean population among systems is

248,000 people (EPA, 2000a). In its cost

estimates, EPA considers the

distribution of flow rates within each

size category for estimating system level

cost contributions to the national impact

(EPA, 2000h; EPA, 2000o). Third, Table

4.6 of the Cost Implication Report (Frey

et al., 2000) provides a distribution of

ground water systems nationally by

system size and arsenic concentration,

and indicates there are no ground water

systems serving more than 1,000,000

projected to have arsenic concentrations

that exceed 5 μg/L. Since no ground

water systems serving more than

1,000,000 people need to treat for MCL

options of 5 μg/L or higher, the national

costs given in the revised report due to

the revised flow rate assumptions in all

categories should be lower for MCL

options at or above 5 μg/L.

On a related issue, EPA believes that

the operation and maintenance cost

equations for anion exchange, activated

alumina, coagulation/microfiltration,

and nanofiltration in the Cost

Implication Report (Frey et al., 2000)

were based on design flow rather than

average flow. Using the operational and

maintenance cost equations based on

design flow rather than average flow

significantly increases cost estimates,

particularly for smaller systems (EPA’s

analysis indicates that for systems with

a design flow of 1 M.D., the total

annualized costs would increase by

about 25% and for systems with a

design flow of 10 M.D., the total

annualized costs would increase by

about 5%).

Unit Cost assumptions: The Cost

Implication Report (Frey et al., 2000)

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7041

develops unit cost equations for a

technology type based on a wide range

of operating conditions, some of which

may not be very cost effective (e.g.,

anion exchange with sulfate

concentrations ranging from 25 to 150

mg/l). Because of their recognized lack

of cost effectiveness for particular

situations, the technologies have limited

application in the national compliance

forecast, even in situations with sulfate

concentrations less than 25 mg/L. This

costing approach tends to overestimate

costs for systems with favorable site

specific conditions. On the other hand,

EPA developed cost equations for

technology types within an operating

range for which the technology can most

cost effectively operate (e.g., anion

exchange with sulfate concentrations of

less than 25 mg/L) and used these

equations for the limited number of

systems that would meet the

constraints. Utilities would not likely

choose technologies unless they were

favorable to use and thus only those

conditions at which the technology is

used should be costed, in our view.

EPA believes that the Cost Implication

Report case study costs for activated

alumina were significantly

overestimated due to the vessel costs.

The vendor quote used for vessel costs

is for a complete activated alumina

system, including the costs for vessels,

media, pipes and valves, chemical feed

and storage, start-up, shipping and

contingencies. The vendor quote

presents budget prices for three design

flows and different size vessels are used

for each design flow. The vessel sizes

are listed with the budget price, along

with many additional costs, which may

have been a source of confusion. Since

activated alumina is the most used

technology in the compliance forecast in

the Cost Implications Report, double

counting full system costs for activated

alumina will significantly affect

national cost estimates, particularly for

smaller systems.

Arsenic occurrence assumptions. The

occurrence distributions based on the

Frey and Edwards (1997) National

Arsenic Occurrence Survey (NAOS)

change throughout Chapter 4 of the Cost

Implication Report. The national

compliance costs are based on the

occurrence distribution with the highest

number of systems above the MCL

options, but no basis is given for this

selection. EPA believes that the arsenic

occurrence distribution used in the

report for the compliance forecast

analysis significantly overestimates the

distribution of arsenic occurrence above

20 μg/L and this significantly biases

costs upward.

2. Affordability

Many commenters expressed concern

that their system, or many households

served by their system, would be unable

to afford to comply with the proposed

arsenic standard and that the DWSRF

would be incapable of providing

significant assistance. Concerns relating

to costs and burden contributed to the

Agency’s decision to promulgate a

standard of 10 μg/L rather than the

proposed standard of 5 μg/L. The

Agency’s decision to promulgate a

standard of 10 μg/L significantly

reduces the impacts on small systems.

At the proposed standard of 5 μg/L,

about 6,500 community water systems

would have needed to install treatment.

At the promulgated standard of 10 μg/

L, about 2,800 small community water

systems (and 1100 NTNCWS) will need

to install treatment. Total capital costs

for the promulgated standard are 57%

lower (for both community water

systems and NTNCWS) than they would

have been for the proposed standard.

Although the number of systems

needing to treat at the promulgated

standard is well under one half of the

number that would have needed to treat

at the proposed standard, the household

level impact for those systems needing

to treat is about the same.

The Agency believes that affordability

of drinking water at the household level

is a function of two key variables: price

of the water and the ability of the

household to pay. Each of these two key

variables is, in turn, a function of a

number of other variables. A

comprehensive and meaningful analysis

of affordability for an individual system

must include a complete assessment of

all of the variables that influence both

price and ability to pay. These variables

are highly site specific. That is why the

framework for addressing affordability

concerns in SDWA consists of two

distinct parts: (1) A national level

affordability analysis focused on

assessing what would be affordable

(from a national perspective) for typical

systems in a size class, and (2) Statelevel analysis, using State-developed

criteria, to assess affordability for any

specific system.

The price of drinking water (the

actual charge imposed on the household

for its water service) reflects the

complex interplay of many variables.

These variables include the water

system’s full cost of doing business,

subsidies or other forms of financial

assistance that offset some of the

system’s costs, and the allocation of

costs by the water system to its users

and the rate design employed by the

water system. The system’s cost of

providing service is influenced by many

different factors, e.g., the quality of the

source water available to the system, the

type of treatment employed and the skill

of its operation, and the basic

organizational or institutional structure

of the water system. Systems that

effectively work together, perhaps by

combining management, will realize

lower overall costs compared to the

same systems working independently.

Section I.L discusses Federal financial

assistance which is available to help

systems comply with arsenic and other

drinking water standards. Section III.E.4

further discusses issues considered by

EPA in assessing the affordability of the

arsenic rule.

One commenter submitted a study

which concludes that establishing a new

arsenic MCL at a level of 5 μg/L (or

lower) will raise serious concerns about

the affordability of water service for a

majority of affected ground water

systems. The Agency reviewed the

study and notes a number of significant

deficiencies in its assumptions and

general methodology. The Agency

disagrees with the commenter’s

selection of $50 per household per year

as affordable on the basis of

expenditures on lottery tickets and with

the commenter’s selection of $100 per

household/year as posing ‘‘serious

affordability concerns’’ on the basis of it

representing some percentage of

expenditures on health care or

telephone service. The Agency notes

that the Consumer Expenditure Survey,

compiled by the Bureau of Labor

Statistics, offers a broad overview of

expenditure patterns across households

of various incomes. The Consumer

Expenditure Survey’s data do not

necessarily support the contention that

an increase in water bills would force a

low-income household to trade off

health care or some other ‘‘essential’’

expenditure to pay the water bill.

Clearly, however, individual household

circumstances vary greatly and certain

individual households may face

difficult choices. Another important

consideration is that assessing

expenditure trade offs by low-income

households must fully account for all

the assistance such households can

receive, including subsidized housing,

medical care through Medicaid, food

stamps, and so on. Simply looking at a

low-income household on the basis of

its cash income can overlook important

assistance available. The commenter

also assumes that if a regulation

increases the cost of water by 0.5% of

median household income in a

community, it might raise an

affordability concern. The commentor

7042 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

justifies this value by asserting that such

an increase would be more than a 50%

increase in the water bill for a typical

household. The Agency finds this

argument unconvincing. For a

household with the median income, the

water bill would represent about 0.9%

of income. It is widely acknowledged

that water has been historically

underpriced. Thus, saying that no more

than a 50% increase would be

affordable is to accept the historic

underpricing as appropriate. The

commenter also assumes the cost

estimates that EPA believes are

significantly overestimated are correct.

Thus, the commenter’s conclusion that

establishing a low arsenic standard will

raise serious concerns about the

affordability of water service for a

majority of affected ground water

systems is unsupported. The subsequent

conclusion that existing variance and

grant programs would not be adequate

to alleviate affordability concerns is

likewise unsupported. (See section I.H.

of today’s preamble for a discussion of

variances and exemptions and section

I.L. for a discussion of financial

assistance available for complying with

this rule.)

A number of commenters indicated

that they did not agree with EPA’s

approach for assessing national level

affordability. Affordability is a complex

concept. Numerous different approaches

have been developed for assessing

affordability of drinking water and/or

wastewater service. Many of these

approaches are summarized in the

Agency’s publication ‘‘Information for

States on Developing Affordability

Criteria for Drinking Water’’ (EPA,

1998a). It is essential that the specific

purpose for which any affordability

criterion is developed be clearly

understood. EPA’s national affordability

criteria are developed and applied for a

very narrow and specific purpose.

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

amended, requires EPA to list

technology (considering source water

quality) that achieves compliance with

the MCL and is affordable for systems in

three specific population size categories:

25–500, 501–3300, and 3301–10,000

when promulgating a national primary

drinking water regulation which

establishes an MCL. If, for any given

size category/source water quality

combination, an affordable compliance

technology cannot be identified, section

1412(b)(15)(A) requires the Agency to

list a variance technology. Variance

technologies may not achieve full

compliance with the MCL but they must

achieve the maximum contaminant

reduction that is affordable considering

the size of the system and the quality of

the source water. In order for the

technology to be listed, EPA must

determine that this level of contaminant

reduction is protective of public health.

Thus, EPA developed national

affordability criteria for the narrow and

specific purpose of determining whether

or not an affordable compliance

technology exists, from a national

perspective, for the specified size

categories of systems, considering the

quality of source waters available to

them. The key point at issue here is

what EPA should consider ‘‘affordable’’

from a national perspective. EPA does

not define national level affordability in

terms of what would be affordable to the

least affluent water systems. Likewise,

EPA does not define national level

affordability in terms of what would be

affordable to the most affluent water

systems. Rather, a determination of

national level affordability is concerned

with identifying, for each of the given

size categories, some central tendency

or typical circumstance relating to their

financial wherewithal.

The metric EPA selected for this

purpose is the median household

income for communities of the specified

sizes. Some commenters expressed

concern that EPA was using the national

median household income (across all

sizes of systems) in making judgments

on national-level affordability. The

Agency wishes to clarify that this was

not the case. We used median

household income for communities of

the specified size categories, as

documented in EPA’s August 6, 1998

Federal Register notice (EPA, 1998h).

The household is thus the focus of the

national-level affordability analysis.

EPA considers treatment technology

costs affordable to the typical household

if they represent a percentage of MHI

that appears reasonable when compared

to other household expenditures. This

approach is based on the assumption

that the affordability to the median

household served by the CWS can serve

as an adequate proxy for the

affordability of technologies to the

system itself. The national-level

affordability criteria have two major

components: current annual water bills

(baseline) and the affordability

threshold (total % of MHI directed to

drinking water). Current annual water

bills were derived directly from the

1995 Community Water System Survey.

Based on 1995 conditions, 0.75–0.78%

of MHI is being directed to water bills

for systems serving fewer than 10,000

persons.

The fundamental, core question in

establishing national-level affordability

criteria is: what is the threshold beyond

which drinking water would no longer

be affordable for the typical household

in each system size category? Based

upon careful analysis, EPA believes this

threshold to be 2.5% of MHI. In

establishing this threshold, the Agency

considered baseline household

expenditures (as documented in the

1995 Consumer Expenditure Survey,

Bureau of Labor Statistics) for piped

water relative to expenditure

benchmarks for other household goods,

including those perceived as substitutes

for higher quality piped water such as

bottled water and POU/POE devices.

Based on these considerations, EPA

concluded that current household water

expenditures are low enough, relative to

other expenditures, to support the cost

of additional risk reductions. The

detailed rationale for the selection of

2.5% MHI as the affordability threshold

is provided in the guidance document

entitled ‘‘Variance Technology Findings

for Contaminants Regulated Before

1996’’ (EPA, 1998l). The difference

between the affordability threshold and

current water bills is the available

expenditure margin. This represents the

dollar amount by which the water bill

of the typical (median) household could

increase before exceeding the

affordability threshold of 2.5% of MHI.

The Agency recognizes that baseline

costs change over time as water systems

comply with new regulations and

otherwise update and improve their

systems. MHI also changes from year to

year, generally increasing in constant

dollar terms. For example, since 1995

MHI has increased (in 1999$) by 9.6%.

Thus, to determine the available

expenditure margin (the difference

between the affordability threshold and

the baseline) for each successive rule,

adjustments would need to be made in

both the baseline and the MHI. The

Agency believes that, for purposes of

assessing national-level affordability of

the arsenic rule, the unadjusted baseline

and unadjusted MHI are appropriate.

Making adjustments to these two factors

would not materially alter the outcome

of the analysis, since both the baseline

and the MHI would increase, and not by

dramatically differing percentages. Thus

the difference between the two would

not significantly change.

By definition, the MHI is the income

value exactly in the middle of the

income distribution. The median is a

measure of central tendency; its purpose

is to help characterize the nature of a

distribution of values. The Agency

recognizes that there will be half the

households in each size category with

incomes above the median, and half the

households with incomes below the

median. The objective of a nationallevel affordability analysis is not to

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7043

determine what is affordable to the

poorest household in the U.S. Nor is it

to determine what the richest household

in the U.S. could afford. Rather, it is to

look across all the households in a given

size category of systems and determine

what is affordable to the typical, or

‘‘middle of the road’’ household.

The distinction between nationallevel affordability criteria and

affordability assessments for individual

systems cannot be over-emphasized.

The national-level affordability criteria

serve only to guide EPA on the listing

of an affordable compliance technology

versus a variance technology for a given

system size/source water combination

for a given contaminant. In the case of

arsenic, EPA determined that nationally

affordable technologies exist for all

system size categories and has therefore

not identified a variance technology for

any system size/source water

combination. This means that EPA

believes that the typical household in

each system size category can afford the

costs associated with the listed

compliance technologies. EPA

recognizes that individual water

systems may serve a preponderance of

households with incomes well below

the median, or may face unusually high

treatment costs due to some unusual

local circumstance. As discussed more

fully in sections I.H, I.L, and III.F.4,

there are a number of tools available to

address affordability concerns for these

individual water systems. The major

tools are financial assistance (lowinterest loans and grants); extended

compliance time-frames under a Stateissued exemption; life-line and other

types of rate structures that systems may

use; and, restructuring of system

management and operations through

partnerships among systems.

3. Combined Cost of New Regulations

A number of commenters expressed

concern about the cumulative cost to

water systems of new drinking water

regulations. The Agency recognizes this

concern and acknowledges that there is

a small percentage of systems faced with

co-occurrence and for whom there will

be multiple treatment requirements.

However, for such systems, the Agency

notes that installation of treatment for

one contaminant (such as arsenic, in

this case) may often reduce the amount

of treatment needed to remove many

types of subsequently regulated

contaminants, since the initial treatment

will likely remove at least some of the

subsequently regulated contaminant;

particularly, certain types of inorganic

contaminants.

The most common cumulative impact

will be that associated with initial

monitoring. Most systems will need to

conduct at least some limited initial

monitoring for most regulated

contaminants. However, for the vast

majority of systems that will not detect

the contaminant at levels of concern,

subsequent monitoring will be limited

and infrequent, with monitoring

variances available for up to once every

nine years.

4. Projected Effects of the New Standard

on Other Regulatory Programs

Several commenters felt that EPA has

underestimated the costs of the

proposed rule by failing to fully

consider the possible costs of a new,

lower drinking water standard on other

regulatory programs, particularly

hazardous waste. EPA disagrees and

does not believe that certain ancillary

costs identified by commenters should

be considered in the cost of compliance

analysis nor should they be a factor

considered in establishing the MCL. For

instance, the prospective costs of future

CERCLA site clean-up actions are not

among the factors that SDWA requires

EPA to consider in establishing an MCL.

Moreover, there are a host of sitespecific factors taken in account in any

CERCLA site clean-up situation beyond

the clean-up standard itself (which may

be an MCL under the CERCLA

requirement to consider ‘‘applicable or

relevant and appropriate requirements’’

(ARARs)). In the case of RCRA, EPA

notes that the arsenic in drinking water

final rulemaking does not necessarily

trigger a revision of the Toxicity

Characteristic standard under RCRA.

Thus, there are not necessarily any new

costs to entities affected by RCRA

requirements as a result of this

rulemaking. In any case, SDWA section

1412(b)(3)(C)(i)(III) specifically excludes

consideration of such costs from other

regulatory programs in the development

of drinking water standards.

H. Benefits of Arsenic Reduction

Significant comments on the benefits

analysis for the proposed arsenic rule

addressed the topics of the timing of

health benefits accrual (latency); the use

of the Value of Statistical Life (VSL) as

a measure of health benefits; the use of

alternative methodologies for benefits

estimation; the Agency’s consideration

of non-quantifiable benefits in its

regulatory decision-making process; the

Agency’s analysis of incremental costs

and benefits of the proposed arsenic

rule; and, the Agency’s assumption that

health risk reduction benefits will begin

to accrue at the same time costs begin

to accrue.

1. Timing of Benefits Accrual (Latency)

Some commenters argued that EPA

should have discounted its health

benefits for the arsenic rule over a

cancer latency period. As noted in the

proposed rule, EPA committed to taking

this issue before the Science Advisory

Board (SAB) for its advice and

recommendations.

EPA brought this issue before the SAB

in a meeting held on February 25, 2000

in Washington, DC (65 FR 5638,

February 4, 2000; EPA, 2000a). The SAB

submitted a final report on their

findings and recommendations to us on

July 27, 2000 (EPA, 2000j). This final

report was made available on the EPA

website at www.epa.gov/sab/

eeacf013.pdf.

The SAB Panel noted that benefit-cost

analysis, as described in the Agency’s

Guidelines [for economic analysis], is

not the only analytical tool nor is

efficiency the only appropriate criterion

for social decision making, but notes

that it is important to carry out such

analyses in an unbiased manner with as

much precision as possible. In its report,

the SAB recommended that the Agency

continue to use a wage-risk based VSL

as its primary estimate; any appropriate

adjustments that are made for timing

and income growth should be part of the

Agency’s main analysis while any other

proposed adjustments should be

accounted for in sensitivity analyses to

show how results would change if the

VSL were adjusted for some of the major

differences in the characteristics of the

risk and of the affected populations.

Specifically, the SAB report

recommended that: (1) Health benefits

brought about by current policy

initiatives (i.e., after a latency period)

should be discounted to present value

using the same rate that is used to

discount other future benefits and costs

in the primary analysis; (2) adjustments

to the VSL for a ‘‘cancer premium’’

should be made as part of a sensitivity

analysis; (3) adjustments to the VSL for

voluntariness and controllability should

be made as part of a sensitivity analysis;

(4) altruism should be addressed in a

sensitivity analysis and separately from

estimation of the value of a statistical

cancer fatality and the circumstances

under which altruism can be included

in a benefit-cost analysis are restrictive;

(5) estimates of VSLs accruing in future

years should be adjusted in the primary

analysis to reflect anticipated income

growth, using a range of income

elasticities; (6) adjustments to the VSL

for risk aversion should be made in a

sensitivity analysis; (7) it is theoretically

appropriate to calculate WTP for

individuals whose ages correspond to

7044 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

those of the affected population, but that

more research should be conducted in

this area; and (8) no adjustment should

be made to the VSL to reflect health

status of persons whose cancer risks are

reduced.

Consistent with the recommendations

of the SAB, EPA developed a sensitivity

analysis of the latency structure and

associated benefits for arsenic, a

summary of which is shown in Section

III.E of the final preamble. This analysis

consists of health-risk reduction benefits

which reflect adjustments for

discounting, incorporation of a range of

latency period assumptions,

adjustments for growth in income, and

incorporation of other factors such as a

voluntariness and controllability.

Although the SAB recommended

accounting for latency in a primary

benefits analysis, the Agency believes

that, in the absence of any sound

scientific evidence of latency periods for

arsenic related cancers, discounted

benefits estimates for arsenic are more

appropriately accounted for in a

sensitivity analysis. Sensitivity analyses

are generally reserved for examining the

effects of accounting for highly

uncertain factors, such as latency

periods, on health risk reduction

benefits estimates.

2. Use of the Value of Statistical Life

(VSL)

Some commenters felt that the Value

of Statistical Life (VSL) used by EPA in

its analysis of benefits for the arsenic

rule was incorrect. EPA disagrees with

these commenters for several reasons.

First, the VSL used by the Agency in its

benefits analysis is based on the most

current data available. The VSL, as

recommended by Agency guidance and

EPA’s SAB, is derived from a statistical

distribution of the values found in 26

wage-risk studies, which were chosen as

the best such studies available from a

larger body of studies. This examination

of studies was undertaken by EPA’s

Office on Air and Radiation in the

course of its Clean Air Act retrospective

analysis. EPA believes the VSL estimate

($6.1 million, 1999 dollars) to be the

best estimate at this time and is

recommending that this value be used

by the various program offices within

the Agency. This estimate may,

however, be updated in the future as

additional information becomes

available to assist the Agency in refining

its VSL estimate. The VSL estimate is

consistent with current Agency

economic analysis guidance, which was

reviewed by EPA’s SAB.

Also, the use of the VSL for benefits

valuation is consistent with

recommendations from EPA’s SAB,

which discussed this issue in their

meeting on February 25, 2000 in

Washington, DC. The SAB’s report on

their findings and recommendations

from the February meeting stated that:

despite limitations of the VSL estimates,

these seem to offer the best available basis at

present for considering the value of fatal

cancer risk reduction. We therefore

recommend that the Agency continue to use

a wage-risk-based VSL as its primary

estimate, including appropriate sensitivity

analyses to reflect the uncertainty of these

estimates (EPA, 2000j).

In addition, some commenters

disagreed with EPA’s valuation of a

human life. EPA disagrees with these

commenters because the VSL does not

represent the value of an actual human

life. Rather, the VSL represents the

value of people’s willingness to pay for

small changes in the risk of a fatality.

3. Use of Alternative Methodologies for

Benefits Estimation

Several commenters suggested that

the Agency use a Quality Adjusted Life

Years (QALYs) or a Life Years approach

in its valuation of health benefits for the

arsenic rule. EPA disagrees with these

commenters because the current

economic literature does not support

these methodologies and EPA believes

these approaches are not sufficient for

use in economic analyses.

The use of alternative methodologies,

such as Quality Adjusted Life Years

(QALYs) and a Life-Years approach, has

been extensively discussed both within

EPA and also before the Environmental

Economics Advisory Committee (EEAC)

of EPA’s SAB. The QALY method

allows information on life expectancy

and quality of life to be combined into

a single number for benefits valuation

purposes. QALYs involve rating each

year of life on a scale from zero to one,

where one represents perfect health and

zero represents the worst possible

health state. Because patients

themselves, or sometimes citizens of the

community, are responsible for ‘‘rating’’

each year, these quality-of-life tradeoffs

are highly subjective and may not be

very meaningful. Regarding the use of

QALYs, the SAB committee stated that

‘‘there are no published studies that

show that persons with physical

limitations or chronic illnesses are

willing to pay less to increase their

longevity than persons without these

limitations. People with physical

limitations appear to adjust to their

conditions, and their WTP to reduce

fatal risks is therefore not affected. The

EEAC suggests that no adjustments be

made to the VSL to reflect the health

status of persons whose cancer risks are

reduced, unless additional research

documents such effects’’ (EPA, 2000j).

A Life-Years approach involves use of

a Value of Statistical Life Year (VSLY)

measure. The VSLY measure values lifeyears that would be lost if an individual

were to die prematurely. The

relationship between the value of risk

reductions and expected life years

remaining is complex; current research

does not provide a definitive way of

developing estimates of VSLY that are

sensitive to such factors as current age,

latency of effect, life years remaining,

and social valuation of risk reduction.

While age adjustments may be desirable

from a theoretical standpoint, in the

absence of such information, the

mainstream economics literature does

not support developing VSLY estimates.

The SAB’s Environmental Economics

Advisory Committee (EEAC), in its

report, confirmed this finding. The use

of VSLY for valuing life-years lost was

found by the EEAC to not have a

sufficient theoretical and empirical

basis for making any adjustments at this

time. While the EEAC agreed that the

theoretically appropriate method is to

calculate WTP for individuals whose

ages correspond to those of the affected

population, the Committee

recommended that more research be

conducted on this topic before the

Agency makes any adjustments for age

in its estimates of health risk reduction

benefits.

Therefore, because of the limitations

enumerated above, EPA disagrees with

the use of the VSLY as a measure of

benefits. This position has also been

incorporated in the Agency’s Guidelines

for Preparing Economic Analyses (EPA,

2000n). The Agency’s economic analysis

guidelines were reviewed and approved

by the Regulatory Policy Council and

are considered when the Agency makes

economic policy determinations.

At this time, current Agency policy is

to use VSL estimates for the

monetization of health risk reduction

benefits. As noted already, this policy is

also consistent with recommendations

from the EPA’s SAB, which discussed

this issue in a meeting held on February

25, 2000 in Washington, DC.

4. Comments on EPA’s Consideration of

Nonquantifiable Benefits

Some commenters felt that EPA did

not fully consider nonquantifiable

benefits in their decision-making

process. EPA respectfully disagrees with

these commenters. SDWA requires that

the Agency take into consideration any

potential quantifiable and

nonquantifiable benefits associated with

regulating arsenic in drinking water. To

this end, the Agency displayed

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7045

quantifiable costs and benefits and

nonquantifiable benefits in the same

table in the proposal (see Table XI–1 of

the proposed rule), so that quantifiable

and nonquantifiable benefits were given

equal consideration in the

determination of a regulatory level. In

selecting a proposed MCL of 5 μg/L, the

Agency based its risk management

decision on both the quantifiable

bladder and lung cancer benefits and

also on the significant amount of

nonquantifiable benefits associated with

regulating arsenic in drinking water. In

addition, EPA has provided analysis

and considered the nonquantified

benefits in the same manner for the final

rule.

By definition, nonquantifiable

benefits cannot be measured and were

not measured in the benefit-cost

analysis for the arsenic rule. EPA

attempted to consider these potential

benefits in both the proposed and final

rule since the Agency believes they

might occur. Such nonquantifiable

benefits may include skin cancer,

kidney cancer, cancer of the nasal

passages, liver cancer, prostate cancer,

cardiovascular effects, pulmonary

effects, immunological effects,

neurological effects, endocrine effects,

and customer peace-of-mind benefits

from knowing their drinking water has

been treated for arsenic.

As stated in section 1412(b)(4)(C) of

the SDWA, ‘‘* * * the Administrator

shall publish a determination as to

whether the benefits of the maximum

contaminant level justify, or do not

justify, the costs based on the analysis

conducted under paragraph (3)(C).’’

Paragraph (3)(C) contains the

description of the seven Health Risk

Reduction and Cost Analysis elements

that the Agency must consider. These

seven elements include quantifiable and

nonquantifiable heath risk reduction

benefits, quantifiable and

nonquantifiable health risk reduction

benefits from reducing co-occurring

contaminants, quantifiable and

nonquantifiable costs, incremental costs

and benefits, effects of the contaminant

on the general population as well as on

any sensitive sub-populations, possible

increased health risks, and uncertainties

in the analysis of any of these elements.

5. Comments on EPA’s Assumption of

Benefits Accrual Prior to Rule

Implementation

As noted by some commenters, EPA

does not make a benefits adjustment for

the period prior to rule compliance.

EPA does not make this adjustment for

two reasons. First, EPA assumes that

costs accrue during the same period and

does not adjust these costs to account

for a phasing in of the rule. Therefore,

the analysis treats benefits and costs in

exactly the same manner. Second, the

Agency anticipates that many systems

will begin installing treatment prior to

the compliance date. This will ensure

they are in compliance on the date that

the rule takes effect. As treatment is

installed to meet the compliance date,

benefits will begin to accrue to those

served by these systems.

I. Risk Management Decision

1. Role of Uncertainty in Decision

Making

Several commenters questioned the

proposed MCL on the basis of the

uncertainties associated with aspects of

the technical analyses supporting this

rulemaking. Most of these comments

dealt with the Agency’s analysis of the

health effects of arsenic. Section V.B. of

today’s preamble responds to these

comments in more detail, and thus, only

a relatively brief response to these

comments, as they affect the risk

management decision, is offered here.

The uncertainties pointed out by

commenters, together with the

considerable costs of compliance with a

new, lower standard, led several

commenters to suggest that the Agency

promulgate a significantly higher MCL

than was proposed.

In response, EPA believes that several

considerations are important. First, we

note that humans are more sensitive to

arsenic than laboratory animals. Thus,

assessments of the health effects of

arsenic necessarily rely, in part, on

studies in which human populations

have been exposed to relatively high

levels (where demonstrable effects can

be clearly seen and distinguished) and

in which extrapolations to safe levels

can be performed, and very low

probabilities of adverse effects are

projected. Uncertainties are inherent in

any such analysis and would attach to

similar kinds of contaminants (for

which humans are more sensitive than

animals and where no animal model

exists). Second, EPA has more fully

considered the various uncertainties to

which many commenters refer and has

striven to account for them either

qualitatively and quantitatively. Third,

the Agency requested and has carefully

considered the advice of the National

Research Council of the National

Academy of Sciences and the Drinking

Water Committee of the Science

Advisory Board on these issues as a part

of our deliberations leading to a final

MCL. In summary, we believe that our

analysis of the health risks of arsenic in

drinking water is fully supportive of the

final MCL and is based upon the best

available science. While we

acknowledge that uncertainties in our

understanding of the health effects of

arsenic remain, we believe there is

sufficient information to support today’s

promulgated standard.

2. Agency’s Interpretation of Benefits

Justify Costs Provision

Many commenters offered a variety of

points of view on EPA’s cost-benefit

analysis and on its interpretation of the

provision of SDWA allowing the

Administrator to set a level higher than

the feasible level if the benefits of a

standard do not justify the costs (section

1412(b)(6) of SDWA). EPA appreciates

the many comments on its cost-benefit

analysis, but respectfully disagrees with

those comments that suggest its analysis

is fundamentally flawed and does not

support the proposed or final rule.

Assessment of cost and benefits in cases

where not all information can be

precisely known, as is the case here, is

a challenging exercise. Sections V.G.

and V.H. of this preamble to the final

rule provide a more detailed response to

the various cost and benefit estimation

comments received. In summary, we

believe these costs and benefits have

been correctly calculated, within the

limits of available data and information,

and that they adequately support both

the proposed and final rule. Consistent

with our statutory requirements, we

have carefully considered costs and

benefits analysis in proposing and

promulgating a final rule that includes

an MCL higher than the feasible level.

Based on our further analysis of a

variety of factors, including the costs

and benefits, and after consideration of

the various comments, we have decided

to establish the final MCL at a higher

level than proposed. As discussed in

detail in section III.F. of this preamble,

the Agency believes that, at an MCL of

10 μg/L, the benefits justify the costs. In

our deliberations, we examined total

national costs and benefits, incremental

costs and benefits across various

optional regulatory levels, and

household costs for various system size

categories. However, it is important to

recognize that the Agency is also

required to comply with the statutory

requirement to ‘‘maximize health risk

reduction.’’ Thus, while evaluation of

costs and benefits is a key consideration

in the exercise of the discretionary

authorities under section 1412(b)(6) of

the SDWA, the decision criteria used in

developing a final MCL also has an

important risk reduction component.

Some commenters also stated their

belief that the benefits must exceed the

costs in order for a particular standard

to be ‘‘justified’’ in accordance with

7046 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

section 1412(b)(6) of SDWA. EPA

disagrees and believes, for several

reasons, that the benefits of the final

standard do justify the costs. First, in

connection with this rulemaking, EPA

notes that there are a number of nonmonetizable benefits that limit the value

of a strict numeric comparison of costs

and benefits. Second, EPA has

calculated a range of monetizable

benefits and believes that a portion of

the range of benefits do, in fact,

‘‘overlap’’ the costs. Finally, EPA notes

that Congressional report language

clarifies the intent of section 1412(b)(6)

and indicates that benefits do not need

to strictly equal or exceed costs in order

for a particular regulatory standard

associated with those costs to be

justified. (see S. Rep. 104–169, 104th

Cong., 1st Sess. at 33.)

3. Alternative Regulatory Approaches

A number of commenters suggested

that EPA tailor the arsenic drinking

water standard in light of local or

regional considerations. Market-based

and seasonal standards were suggested

in this regard. EPA understands these

comments and the desire of these

commenters to exercise flexibility in

local or Regional decision-making in

order to reflect information about local

arsenic occurrence patterns, local public

health priorities, available resources, or

other pertinent factors. EPA notes that

SDWA does provide for local and

Regional flexibility in the

implementation of new standard in a

variety of ways. State decisions on use

of State Revolving Loan Funds and

Public Water System Supervision grant

funds should be based upon local needs,

local priorities, and available local

funds. In addition, States may provide

variances to qualifying systems under

section 1415(a) of SDWA. States may

also grant exemptions to qualifying

water systems to provide additional

time to comply with a new standard

(with an opportunity for extensions) to

help address the kinds of situations that

many commenters are concerned about.

However, SDWA does not provide a

basis for establishing regional, local, or

further-tailored drinking water

standards as these commenters suggest.

Rather, SDWA is designed to ensure

uniform levels of public health

protection across the country (except as

specifically provided for in variances

from the standard). In addition, certain

Executive Orders such as Executive

Order Number 12898 (Environmental

Justice) reinforce this SDWA

requirement and are specifically

designed to ensure that disadvantaged

communities are not protected at levels

that are less than those afforded

nationally. Thus, EPA disagrees with

the suggestion that the level of the final

standard be altered to address local or

regional considerations, or otherwise

tailored, except as specifically provided

for by SDWA.

4. Standard for Total Arsenic vs.

Species-Specific Standards

Several commenters expressed

concern that an arsenic in drinking

water standard based on total arsenic

may unfairly penalize many drinking

water systems, since these commenters

felt that only inorganic forms of arsenic

are considered to be toxic. Thus, the

argument goes: the portion of a

compliance sample that is comprised of

organic arsenic would unfairly ‘‘count

against’’ the utility when determining

whether or not the concentration of

arsenic in the sample exceeds the MCL.

EPA believes, based on our

understanding of occurrence patterns of

arsenic, that source waters

overwhelmingly contain inorganic

arsenic. However, EPA also believes that

there is a recent body of scientific

evidence that indicates organic arsenic

may also be toxic. Thus, it is important

to know the total amount of arsenic

present—both inorganic and organic.

Allowing for only the relative

concentration of inorganic arsenic to be

measured in compliance samples would

impose an additional expense and

would only account for a portion of the

potentially toxic arsenic present. EPA

does not believe such an approach is

appropriate for the reasons discussed

and instead believes the final MCL

should be expressed as total arsenic.

J. Health Risk Reduction and Cost

Analysis (HRRCA)

1. Notice and Comment Requirement

Several commenters stated that EPA

was required to publish the HRRCA for

public comment prior to proposing the

arsenic regulation. EPA respectfully

disagrees with these commenters.

SDWA section 1412(b)(3)(C) states that

‘‘when proposing any national primary

drinking water regulation that includes

a maximum contaminant level, the

Administrator shall, with respect to a

maximum contaminant level that is

being considered in accordance with

paragraph (4) and each alternative

maximum contaminant level that is

being considered pursuant to paragraph

(5) or (6)(A), publish, and seek comment

on, and use for purposes of paragraphs

(4), (5), and (6) an analysis of * * *’’ the

quantifiable and nonquantifiable health

risk reduction benefits, the quantifiable

and nonquantifiable health risk

reduction benefits from reducing cooccurring contaminants, the quantifiable

and nonquantifiable costs, the

incremental costs and benefits, the

effects of the contaminant on the general

population as well as on any sensitive

subpopulations, any possible increased

health risks, and uncertainties in the

analysis of any of the above factors.

The above section of the statute

provides for the publication of the

HRRCA for any contaminant, except

radon in drinking water, concurrently

with the proposed regulation. Had

Congress intended for the arsenic

HRRCA to be published in advance of

the proposal, the statute would have

specifically provided for that, as it did

in the case of radon. Section

1412(b)(13)(C) refers to the specific

requirements for radon in drinking

water. In this section of the statute,

Congress required the Agency to publish

the HRRCA for radon in drinking water

six months in advance of the proposal.

In the proposed arsenic rule, the

Agency provided an analysis of the

costs, benefits, and other HRRCA

requirements, which was shown in

Section XIII of the preamble to the

proposed rule. The public was provided

a 90-day comment period in which to

submit comments on all aspects of the

proposed rule, including costs, benefits,

and HRRCA requirements.

2. Conformance With SDWA

Requirements

Some commenters felt that EPA did

not meet the statutory requirements for

conducting a HRRCA in section

1412(b)(3)(C)(i) and did not analyze the

incremental costs and benefits

associated with each alternative

maximum contaminant level considered

in conformance with SDWA

requirements. EPA has met these

requirements by conducting a HRRCA

and an incremental analysis which are

described in section XIII.D. of the

preamble for the proposed rule. The

HRRCA requirements, incremental

costs, and incremental benefits are also

discussed in the Economic Analysis of

the proposed rule.

Some commenters also noted that

EPA’s incremental cost-benefit analysis

lacked significant detail. The Agency

addressed these concerns by adding

more text to the incremental analysis

section in the preamble for the final

rule.

Several other commenters stated that

the proper interpretation of SDWA is to

use only an incremental analysis to

determine if the benefits justify the

costs. EPA respectfully disagrees with

this interpretation because section

1412(b)(4)(C) of SDWA states ‘‘***

the Administrator shall publish a

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7047

determination as to whether the benefits

of the maximum contaminant level

justify, or do not justify, the costs based

on the analysis conducted under

paragraph (3)(C).’’ Paragraph (3)(C)

contains the description of the seven

Health Risk Reduction and Cost

Analysis elements that the Agency must

consider. These seven elements include

quantifiable and nonquantifiable health

risk reduction benefits, quantifiable and

nonquantifiable health risk reduction

benefits from reducing co-occurring

contaminants, quantifiable and

nonquantifiable costs, incremental costs

and benefits, effects of the contaminant

on the general population as well as on

any sensitive subpopulations, possible

increased health risks, and uncertainties

in the analysis of any of these elements.

The Agency must consider all seven

elements, not just incremental benefits

and costs, when making a determination

as to whether the benefits of the

proposed rule justify the costs.

VI. Administrative and Other

Requirements

A. Executive Order 12866: Regulatory

Planning and Review

Under Executive Order 12866, (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:

• 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;

• Create a serious inconsistency or

otherwise interfere with an action taken

or planned by another agency;

• Materially alter the budgetary

impact of entitlements, grants, user fees,

or loan programs or the rights and

obligations of recipients thereof, or;

• 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’’ because it will have annual

costs of more than $100 million. As

such, this action was reviewed by OMB.

Changes made in response to OMB

suggestions or recommendations are

documented in the public record. EPA

prepared an Economic Analysis (EA)

pursuant to Executive Order 12866 and

a revised version of the EA is in the

docket for this rule (EPA, 2000o).

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.

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.

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 the Small Business

Administration’s (SBA) Chief Counsel

for Advocacy.

For purposes of assessing the impacts

of today’s rule on small entities, EPA

considered small entities to be PWSs

serving fewer than 10,000 persons. In

accordance with the RFA requirements,

EPA proposed using this alternative

definition in the Federal Register (63 FR

7620, February 13, 1998), requested

comment, consulted with the SBA, and

finalized the alternative definition in

the Consumer Confidence Reports

regulation (63 FR 44511, August 19,

1998). As stated in that final rule, the

alternative definition would be applied

to this regulation as well.

In accordance with section 603 of the

RFA, EPA prepared an initial regulatory

flexibility analysis (IRFA) for the

proposed rule and convened a Small

Business Advocacy Review Panel to

obtain advice and recommendations of

representatives of the regulated small

entities in accordance with section

609(b) of the RFA. A detailed discussion

of the Panel’s advice and

recommendations is found in the Panel

Report (EPA 1999e). A summary of the

Panel’s recommendations is presented

at (65 FR 38963, June 22, 2000). All

Panel’s recommendations directly

applicable to this rulemaking are

included in this final rule.

As required by section 604 of the

RFA, EPA also prepared a final

regulatory flexibility analysis (FRFA) for

today’s final rule. The FRFA in

combination with today’s preamble,

addresses the issues raised by public

comments on the IRFA, which was part

of the proposal of this rule. The FRFA

is available for review in the docket,

(EPA 2000w) and is summarized below.

The RFA requires EPA to address the

following when completing an FRFA:

(1) A succinct statement of the need

for, and objectives of, the rule;

(2) A summary of the significant

issues raised by the public comments on

the IRFA, a summary of the assessment

of those issues, and a statement of any

changes made to the proposed rule as a

result of those comments;

(3) A description of the reporting,

recordkeeping, and other compliance

requirements of the rule, including an

estimate of the classes of small entities

which will be subject to the rule and the

type of professional skills needed to

prepare the report or record;

(4) A description of the types and

number of small entities to which the

rule will apply, or an explanation why

no estimate is available; and

(5) a description of the steps taken to

minimize the significant impact on

small entities consistent with the stated

objectives of the applicable statutes,

including a statement of the factual,

policy, and legal reasons why EPA

selected the alternative the final rule

and why the other significant

alternatives to the rule that were

considered which affect the impact on

small entities were rejected.

The following is a summary of the

FRFA. The first requirement is

discussed in section II. and III.D.1 of

this preamble. The second, third, fourth

and fifth requirements are summarized

as follows.

a. Comments on the IRFA.

Commenters on the IRFA raised a

number of issues, largely concerned

with the potential cost of the rule. In the

proposed arsenic rule and the RIA

supporting the proposal (EPA 2000h),

EPA estimated the costs for small

systems for the four arsenic MCL

regulatory options and requested

comment on the IRFA. Some

commenters felt that EPA had

underestimated the costs for small

systems to comply with the arsenic

proposal. In response to the comments,

the Agency re-evaluated the economic

effects on small entities after

publication of the proposal (as

discussed in greater detail in Section

III.). EPA updated its assessment for the

FRFA based on comments and the final

regulatory decisions, i.e., the final MCL

level, full coverage of NTNCWS, and

updated costs of compliance, including

waste disposal costs.

7048 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

b. Reporting, Recordkeeping and

Other Requirements for Small Systems.

The arsenic rule continues to require

small systems to maintain records and

to report arsenic concentration levels at

the point-of-entry to the water system’s

distribution system. NTNCWSs are

added to the systems that must meet the

MCL for arsenic by this rulemaking.

Small systems are also required to

provide arsenic information in the

Consumer Confidence Report or other

public notification if the system exceeds

specific arsenic finished water

concentrations including 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 and a reporting requirement when

one half of the MCL is exceeded (see

section V.E.). 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.

c. Number of Small Entities Affected.

The number of small entities subject to

today’s rule is shown in Table VI.B–1

below.

TABLE VI.B–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.

EPA’s FRFA estimates that the

economic impact of the final rule will

not be significant for the vast majority

of small systems. Of the 71,011 small

entities potentially affected by the

Arsenic Rule, 94% are expected to incur

average annualized costs of less than

$40. This average reflects total costs for

systems that will not need to modify or

install treatment to meet the MCL and

mostly reflects monitoring costs. This

equates to approximately 0.001% of

average annual revenue. The remaining

6%, 3,907 systems, estimated to need

additional or modified treatment to

meet the MCL are expected to incur

average annualized costs of

approximately $20,816, or 0.70% of

average annual revenue. Although EPA

has worked with small communities to

minimize the burden of compliance

with this rule, the Agency anticipates

that several hundred systems may

nevertheless experience costs in excess

of 3% of annual revenues. As noted

below, financial assistance and

exemptions (providing additional time)

are available for small systems for

compliance.

d. Minimizing small system impact

and the final MCL. As discussed in more

detail in section I.L. of this preamble,

EPA notes that $1.7 billion is available

each year through the SRF and RUS

program to support necessary capital

improvements to ensure compliance.

SDWA also provides small systems

additional time to comply through a

provision for exemptions. Systems

serving fewer than 3,300 persons can

apply for an exemption from the State

(SDWA section 1416(b)(3)) that can

provide up to an additional nine years

to comply (for a total of 14 years from

the effective date of the rule). EPA

discusses in section III.F. of this

preamble the decisions to select the

final MCL. EPA is preparing a small

entity compliance guide to help small

entities comply with this rule as

required by Section 212 of SBREFA.

This guide will be available for small

systems within a few months of the

promulgation date of this rule. Small

systems may obtain a copy of the guide

from EPA’s web site, www.epa.gov/

safewater.

C. Unfunded Mandates Reform Act

(UMRA) of 1995

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, Tribal,

and local governments and the private

sector. Under UMRA section 202, EPA

generally must prepare a written

statement, including a benefit-cost

analysis, for proposed and final rules

with ‘‘Federal mandates’’ that may

result in expenditures by State, Tribal,

and local 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 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

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7049

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.

EPA has determined that this rule

contains a Federal mandate that may

result in expenditures of $100 million or

more for State, Tribal, and local

governments, in the aggregate, or the

private sector in any one year. A

detailed description of this analysis is

presented in EPA’s Economic Analysis

of the arsenic rule (EPA, 2000o) which

is included in the Office of Water docket

for this rule. Accordingly, EPA has

prepared under section 202 of the

UMRA a written statement which is

summarized below.

a. Authorizing legislation. Today’s

rule is issued pursuant to section

1412(b)(13) of the 1996 amendments to

SDWA that 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,

(and subsequently amended to June 22,

2001) to promulgate this rule.

b. Cost-benefit analysis. Section III. of

this preamble, describing the Economic

Analysis (EA) (EPA, 2000o), health risk

analysis and the cost and benefit

analysis for arsenic, contains a detailed

analysis in support of the arsenic rule.

Today’s final rule is expected to have a

total annualized cost of approximately

$181 million (Exhibit 6–9, EPA, 2000o).

This total annualized cost includes the

total annual administrative costs of

State, Tribal, and local governments, in

aggregate, less than 1% of the cost, and

total annual treatment, monitoring,

reporting, and record keeping impacts

on public water systems, in aggregate, of

approximately $1.3 million. EPA

estimates the total annual costs of

administrative activities for compliance

with the MCL to be approximately $2.7

million.

The EA includes both qualitative and

monetized benefits for improvements in

health and safety. EPA estimates the

final arsenic rule will have total annual

monetized benefits for bladder and lung

cancer of approximately $140 to 198

million for the MCL of 10 μg/L. The

monetized health benefits of reducing

arsenic exposures in drinking water are

attributable to the reduced incidence of

fatal and non-fatal bladder and lung

cancers. At an arsenic level of 10 μg/L,

an estimated 21 to 30 fatal bladder and

lung cancers and 12 to 26 non-fatal

bladder and lung cancers per year are

prevented.

In addition to quantifiable benefits,

EPA has identified several potential

non-quantifiable benefits associated

with reducing arsenic exposures in

drinking water. These potential benefits

include health effects that are difficult

to quantify because of the uncertainty

surrounding their estimation. Nonquantifiable benefits may also 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.

c. Financial Assistance. Section III of

this preamble describes the various

Federal programs available to provide

financial assistance to State, Tribal, and

local 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) Grant 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.

Also, the Rural Utilities Service (RUS)

of the United States Department of

Agriculture (USDA) operates a Water

and Waste Disposal Loan and Grant

Program. This program provides lowinterest loans and grants to public

entities and not-for-profit corporations

serving populations of 10,000 or fewer

persons.

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 an

arsenic MCL of 10 μg/L to the extent

reasonably feasible. The Agency

believes that the cost estimates,

indicated previously and discussed in

more detail in section III of today’s rule,

accurately characterize future

compliance costs of the 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. While the percentage

of systems impacted varies from region

to region, no area has impacts

substantial enough to create a

disproportionate burden. For the

proposal, EPA did identify (Table V–2,

p. 38908) that there are a larger

percentage of systems in the Western

and New England regions, whose

drinking water quality currently would

exceed the MCL for arsenic. For such

regions, total compliance, therefore,

may be incrementally costlier than for

systems in regions where a smaller

percentage currently exceed the arsenic

MCL. However, even this difference is

not considered by EPA to represent a

disproportionate impact.

To estimate the potential

disproportionate impacts on social

segments of this rule, this analysis also

developed three other measures:

(1) Reviewing the impacts on small

versus large CWSs;

(2) Reviewing the costs to public

versus private CWSs; and

(3) reviewing the household costs for

the rule.

Table 6–11 of the EA (EPA, 2000o)

shows that the total treatment costs for

small CWSs (serving fewer than 10,000

persons) is less than the total treatment

for large CWSs; therefore, there is no

disproportionate impact on small

systems versus large systems. Table 8–

29 of the EA shows that there is not a

disproportionate impact when

comparing costs for public CWSs to

costs for private CWSs of the same size.

Public systems have slightly higher

costs than public CWSs. Table 8–30 of

the EA show household costs by system

size. Cost per household increases as

system size decreases. Cost per

household is higher for households

served by smaller systems than larger

systems. These values are expected 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 per-capita or per-household

basis, require more expensive treatment

methods to achieve the target arsenic

level.

Moreover, even if there were a

disproportionate impact associated with

the final MCL, EPA does not have any

authority to tailor the regulation to

provide regional or ownership relief.

Finally, as previously noted, EPA

adopted a 10 μg/L arsenic MCL rather

than the proposed (5 μ/L) or feasible

level (3 μg/L) of arsenic MCL in part

because of the benefit cost issues raised

by commenters. This should serve to

mitigate the costs of the rule to some

degree. EPA also provided delayed

compliance deadlines for all systems

7050 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

which should also reduce the economic

effect on systems with higher ground

water arsenic levels.

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.

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% to 0.5% 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 macro-economic

effects on the national economy from

the arsenic rule should be negligible

based on the fact that, assuming 100%

compliance, the total annual costs are

approximately $181 million, 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, Tribal, and local

governments. In developing the

proposed rule, EPA consulted with

small governments pursuant to its plan

established under section 203 of the

UMRA to address impacts of regulatory

requirements in the rule that might

significantly or uniquely affect small

governments. Consistent with the

intergovernmental consultation

provisions of section 204 of UMRA, EPA

held, prior to proposal, consultations

with the governmental entities affected

by this rule. EPA held four public

meetings for stakeholders prior to

proposal and an additional meeting after

proposal. The Agency convened a Small

Business Advocacy Review (SBAR)

Panel in accordance with the Regulatory

Flexibility Act (RFA) as amended by the

Small Business Regulatory Enforcement

Fairness Act (SBREFA) to address small

entity concerns, including small local

governments. EPA consulted with small

entity representatives prior to convening

the Panel to get their input on the

arsenic rule. Two of the small entities

represented small governments. A

detailed description of the SBREFA

process can be found in the docket of

this rulemaking (EPA, 1999e). EPA also

made presentations at Tribal meetings

in Nevada, Alaska, and California. In

addition, EPA made 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.

g. Nature of State, Tribal, and local

government concerns and how EPA

addressed these concerns. In general,

comments on the proposed UMRA

discussion continued to cite costs and

funding for compliance as concerns.

EPA has further revised the costs for

this final rule based on comments and

continues to believe that there are

affordable technologies (see section

III.E.). Cost was one of the issues EPA

considered in deciding to exercise its

discretionary authority under section

1412(b)(6) of SDWA to propose that the

MCL be set a level higher than the

feasible level in the proposed rule of 5

μg/L and to set the final level of 10 μg/

L. Commenters asked that funding be

increased to the Drinking Water State

Revolving Fund (DWSRF) or somehow

fully fund compliance with the

proposed requirements. While the

DWSRF program is proving to be a

significant source of funding, it cannot

be viewed as the only source of funding.

There are strategies other than Federal

funding (such as system bundling) for

meeting the arsenic rule. Federal, State

and local governments, private business

and utilities will need to work in

partnership to help address the

significant infrastructure needs for

complying with today’s rule.

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 (EPA,

2000h) and Health Risk Reduction and

Cost Analysis (HRRCA) for the proposed

arsenic rule (EPA, 2000i, see section

XIII.) evaluated arsenic levels of 3 μg/L,

5 μg/L, 10 μg/L, and 20 μg/L. (see

section III. of the proposed rule for more

discussion of the regulatory alternatives

considered.)

i. Selection of the regulatory

alternative. As explained in section

III.F. of today’s preamble, the Agency

selected an MCL of 10 μg/L which is the

most cost-effective alternative since it

maximizes benefits.

D. Paperwork Reduction Act (PRA)

The Office of Management and Budget

(OMB) has approved the information

collection requirements contained in

this rule under the provisions of the

Paperwork Reduction Act, 44 U.S.C.

3501 et seq, and has assigned OMB

control number 2040–0231.

Under this rule, respondents to the

monitoring, reporting, and

recordkeeping requirements include the

owners and operators of community

water systems and State officials that

must report data to the Agency.

Monitoring for arsenic is required at

each entry point to the distribution

system. States will have discretion in

grandfathering existing data for

determining initial monitoring baselines

for the currently regulated

contaminants.

EPA has estimated the burden

associated with the specific information

collection, record keeping and reporting

requirements of the proposed rule in the

accompanying Information Collection

Request (ICR). The ICR for today’s final

rule compares the current requirements

to the revised requirements for

information collection, reporting and

record-keeping. The States and the

PWSs must perform start-up activities in

preparing to comply with the arsenic

rule. Start-up activities include reading

the final rule to become familiar with

the requirements and training staff to

perform the required activities.

For PWSs, the number of hours

required to perform each activity may

vary by system size. This rule applies to

community water systems and nontransient non-community water

systems. There are approximately

74,607 PWSs and 56 States and

territories considered in this ICR.

During the first three years after

promulgation of this rule, the average

burden hours per respondent per year is

estimated to be 8 hours for PWSs and

915 hours for States. During this period,

the total burden hour per year for the

approximately 74,663 respondents

covered by this rule is estimated to be

667,179 hours to prepare to comply

with this final arsenic rule. The average

number of responses per year by PWSs

is 49,738. The average number of

responses for the States is expected to

be 75 per year during the first three-year

period. The average burden hours per

response for PWSs is 4. The average

burden hours per response for States is

229. Total annual labor costs during this

first 3-year period are expected to be

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7051

about $9.9 million per year for PWSs.

The information collected is not

confidential.

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 ways to comply with any

previously applicable instructions and

requirements; train personnel to collect

information; search data sources;

complete and review the collection of

information; and transmit or otherwise

disclose the information.

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.

EPA is amending the table in Chapter 9

of currently approved ICR control

numbers issued by OMB for various

regulations to list the information

requirements contained in this final

rule.

E. National Technology Transfer and

Advancement Act (NTTAA)

Section 12(d) of the National

Technology Transfer and Advancement

Act of 1995 (NTTAA), (Pub. L. No. 104–

113, section12(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) 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.

Today’s rule does not establish any

technical standards; thus, NTTAA does

not apply to this rule. However, it

should be noted that systems complying

with this rule need to use previously

approved technical standards already

included in § 141.23. As discussed in

the proposed rule for arsenic (65 FR

38888) and in today’s final rule (section

I.F.1.), one consensus method (SM

3120B) and one EPA method (EPA

200.7), are withdrawn by this rule

because the method detection limits for

these methods are inadequate to reliably

determine the presence of arsenic at the

MCL of 10 μg/L. After the removal of

these methods, the four remaining

analytical methods currently approved

for compliance monitoring of arsenic in

drinking water are published by

consensus organizations. The four

methods published by these consensus

organizations include SM 3113B, SM

3114B, ASTM 2972–93B and ASTM

2972–93C. These methods 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).

F. Executive Order 12898:

Environmental Justice

Executive Order 12898 establishes a

Federal policy for incorporating

environmental justice into Federal

agencies’ 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 justice

related issues concerning the potential

impacts of this action and consulted

with minority and low-income

stakeholders.

On March 12, 1998, the Agency held

a stakeholder meeting to address various

components of pending drinking water

regulations and how they may impact

sensitive sub-populations, 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 meetings by video

conference call between 11 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 March 12, 1998

meeting were:

• Solicit ideas from stakeholders on

known issues concerning current

drinking water regulatory efforts;

• Identify key issues of concern to

stakeholders, and;

• Receive suggestions from

stakeholders concerning ways to

increase representation of communities

in EPA 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 regulation.

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

explain why the planned regulation is

preferable to other potentially effective

and reasonably feasible alternatives

considered by the Agency.

This final 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.

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,

imposes substantial direct compliance

costs, and 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 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

7052 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

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 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 in the docket for this proposed

rulemaking. EPA consulted extensively

with State, Tribal, and local

governments. For example, EPA held

four public stakeholder meetings in

Washington, D.C. (two meetings); San

Antonio, Texas; and Monterey,

California. An additional public

stakeholder meeting was held after the

proposal was published in Reno,

Nevada. A summary of this meeting is

included in the docket of this

rulemaking. 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). EPA

officials presented a summary of the

rule to the National Governor’s

Association in a meeting on May 24,

2000. In addition, EPA scheduled a oneday 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.

Several issues were raised by

stakeholders (including elected officials)

regarding the arsenic rule provisions,

most of which were related to reducing

burden and maintaining flexibility. The

Office of Water was able to reduce

burden and increase flexibility for the

proposal in a number of areas in

response to these comments (see section

XIV.G. of the proposed rule).

Commenters on the proposed rule

continued to request a reduction of

burden and increased flexibility as well

as to question the need for the rule.

Section V. of this preamble and the

Comment Response Document (EPA,

2000u) discuss the comments and EPA’s

response in detail. The Agency

exercised its discretionary authority

under section 1412(b)(6) of SDWA to

propose that the MCL be set at a level

higher than the feasible level in the

proposed rule and, in the final rule, to

move from the proposed level of 5 μg/

L to 10 μg/L.

I. Executive Orders 13084 and 13175:

Consultation and Coordination With

Indian Tribal Governments

On November 6, 2000, the President

issued Executive Order 13175 (65 FR

67249) entitled, ‘‘Consultation and

Coordination with Indian Tribal

Governments.’’ Executive Order 13175

took effect on January 6, 2001, and

revokes Executive Order 13084 (Tribal

Consultation) as of that date. EPA

developed this final rule, however,

during the period when Executive Order

13084 was in effect; thus, EPA

addressed tribal considerations under

Executive Order 13984.

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, significantly or uniquely

affects the communities of Indian Tribal

governments, and 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 or uniquely affect

communities of Indian tribal

governments. It may 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 this rule. In developing

the rule, EPA consulted with Tribal

governments to permit them to have

meaningful and timely input into its

development.

In order to inform and involve Tribal

governments prior to proposing the

arsenic rule, EPA staff attended the 16th

Annual Consumer Conference of the

National Indian Health Board on

October 6–8, 1998, convened a Tribal

consultation meeting on February 24–

25, 1999, and conducted a series of

workshops at the Annual Conference of

the National Tribal Environmental

Council on May 18–20, 1999. Tribal

representatives were generally

supportive of an arsenic standard that

ensures a high level of water quality, but

raised concerns over funding for

regulations. With regard to the 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. Comments

submitted on the proposed arsenic rule

repeated the concern that Tribes might

not be able to afford to meet the arsenic

requirements.

The Agency believes that the

requirements of this final rulemaking

are affordable nationally, including

Tribal PWSs. As discussed in section

I.G. of this preamble, EPA has

developed and applied a national

affordability criterion to the projected

costs of compliance of this rule for small

systems (those serving less than 10,000

persons). Using this approach, EPA has

identified affordable compliance

technologies that small systems

(including Tribal PWSs) may use to

comply with today’s final rule.

J. Plain Language

Executive Order 12866 and the

President’s memorandum of June 1,

1998 require each agency to write its

rules in plain language. Readable

regulations help the public find

requirements quickly and understand

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7053

them easily. They increase compliance,

strengthen enforcement, and decrease

mistakes, frustration, phone calls,

appeals, and distrust of government. Of

the several techniques typically utilized

for writing readably, using a question

and answer format, and using the word,

‘‘you’’ for whoever must comply, do the

most to improve the look and sound of

a regulation. The preamble for today’s

final rule uses the first principle and

was developed using a plain language

question and answer format. Today’s

final rule language does not use these

principles since the rule only modifies

or adds to existing regulatory language

that is in the previous regulatory

language format. EPA received

comments on the use of plain language.

Commenters suggested that the Agency

had not clearly explained certain terms

for example, ‘‘dose-response’’ and

‘‘parts per billion.’’ The comments were

centered around technical and scientific

issues and terms that are often difficult

to discuss in a plain language format.

EPA considered these comments in

writing the section of this final rule to

which those comment apply. EPA made

every effort to write this preamble to the

final rule in as clear, concise, and

unambiguous manner as possible.

K. Congressional Review Act

The Congressional Review Act, 5

U.S.C. 801 et seq., as added by the Small

Business Regulatory Enforcement

Fairness Act of 1996, generally provides

that before a rule may take effect, the

agency promulgating the rule must

submit a rule report, which includes a

copy of the rule, to each House of the

Congress and to the Comptroller General

of the United States. EPA will submit a

report containing this rule and other

required information to the U.S. Senate,

the U.S. House of Representatives, and

the Comptroller General of the United

States prior to publication of the rule in

the Federal Register. A major rule

cannot take effect until 60 days after it

is published in the Federal Register.

This action is a ‘‘major rule’’ as defined

by 5 U.S.C. 804(2). This rule will be

effective March 23, 2001.

L. Consultations With the Science

Advisory Board, National Drinking

Water Advisory Council, and the

Secretary of Health and Human Services

In accordance with section 1412 (d)

and (e) of SDWA, the Agency discussed

or submitted possible arsenic rule

requirements to the Science Advisory

Board (SAB), National Drinking Water

Advisory Council (NDWAC), and to the

Secretary of Health and Human Services

and requested comment from the

Science Advisory Board (SAB) on the

arsenic rule.

On March 13th and 14th, 2000 in

Washington DC, the Agency met with

the Science Advisory Board during

meetings open to the public where

several of the Agency’s Drinking Water

Rules were discussed. A copy of the

SAB’s comments may be found in the

docket. SAB provided substantive

comments on the proposed arsenic rule

which are discussed in sections V.B.

and V.F. of this preamble.

In addition, the National Drinking

Water Advisory Council was consulted

on this rulemaking on several occasions

throughout the rule’s development (e.g.,

November 1999 in Baltimore, Maryland;

April 2000 in San Francisco, CA;

November 2000 in Arlington, VA). The

summary of the deliberations and

recommendations of the Council may be

found in the docket for this rule.

The Agency coordinated with the

Department of Health and Human

Services in several ways.

Representatives of the Centers for

Disease Control and Prevention (CDC),

the Agency for Toxic Substances and

Disease Registry (ATSDR), and the Food

and Drug Administration (FDA) were

invited to the Agency’s stakeholder

meetings on the arsenic rulemaking and

on the mailing list for updates. We

provided FDA staff with summaries of

the meetings, meeting materials, and a

briefing paper. In addition, the Agency

maintained contact with CDC

representatives on the status of CDCfunded research on skin adsorption that

could have a bearing on the Agency’s

deliberations. EPA commented on and

monitored the progress of the updated

‘‘Toxicological Profile for Arsenic’’

issued by ATSDR. Finally, we provided

ongoing progress reports on the

Agency’s arsenic in drinking water

rulemaking activities to representatives

of FDA relative to the timing of bottled

water regulations that need to follow the

promulgation of the Agency’s final rule.

M. Likely Effect of Compliance With the

Arsenic Rule on the Technical,

Financial, and Managerial Capacity of

Public Water Systems

Section 1420(d)(3) of SDWA as

amended requires that, in promulgating

a NPDWR, the Administrator shall

include an analysis of the likely effect

of compliance with the regulation on

the technical, financial, and managerial

capacity of public water systems. The

following summarizes the analysis

performed to fulfill this statutory

obligation. (EPA, 2000v)

Overall water system capacity is

defined in guidance (EPA, 1998g) as the

ability to plan for, achieve, and

maintain compliance with applicable

drinking water standards. Capacity has

three components: technical,

managerial, and financial. Technical

capacity is the physical and operational

ability of a water system to meet SDWA

requirements. Technical capacity refers

to the physical infrastructure of the

water system, including the adequacy of

source water and the adequacy of

treatment, storage, and distribution

infrastructure. It also refers to the ability

of system personnel to adequately

operate and maintain the system and to

otherwise implement requisite technical

knowledge. Managerial capacity is the

ability of a water system to conduct its

affairs in a manner enabling the system

to achieve and maintain compliance

with SDWA requirements. Managerial

capacity refers to the system’s

institutional and administrative

capabilities. Financial capacity is a

water system’s ability to acquire and

manage sufficient financial resources to

allow the system to achieve and

maintain compliance with SDWA

requirements.

The arsenic rule establishes five

requirements that may impact the TMF

capacity of PWSs:

(1) Compliance with MCL revised to

10 μg/L from 50 μg/L (40 CFR 141.62);

(2) Revised arsenic monitoring

schedule [(modified to join the standard

monitoring framework (SMF) used for

other inorganic contaminants (IOCs)]

(§ 141.23(c))—includes requirement for

public notification of MCL exceedance,

but not Consumer Confidence Report

(CCR) requirements (§ 141.154);

(3) New source monitoring (§ 141.24);

(4) Removal of EPA Method 200.7 and

SM 3120 from list of approved

analytical methods to demonstrate

compliance (§ 141.23); and

(5) Inclusion of arsenic health effects

language in CCRs (§ 141.154).

The arsenic rule applies to all CWSs

(54,370 systems) and NTNCWSs (20,255

systems)—74,625 systems in all (EPA,

2000b). However, many systems will not

be affected by the new arsenic

requirements. Table VI.M–1 provides a

complete listing of the requirements and

a description of the type and number of

systems affected by each requirement.

7054 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

TABLE VI.M–1.—REQUIREMENTS OF THE ARSENIC RULE AND NUMBER OF SYSTEMS AFFECTED

Requirement

Affected systems 1

Description

Number

CWSs NTNCWSs Total

Compliance with revised MCL (10 μg/L) ........................................ Systems with As ≥ 10 μg/L ........ 3,024 1,080 4,104

Revised monitoring schedule .......................................................... CWSs with As between 3 μg/L

(PQL) and 50 μg/L and all

NTNCWSs.

10,590 20,255 30,845

New source monitoring ................................................................... Systems that develop a new

source to meet the revised

MCL.

∼0 ∼ 0 <100

Removal of specified analytical methods ....................................... All CWSs that currently use

banned methods.

<100 N/A <100

Inclusion of health effects language in CCR .................................. CWSs with As ≥5–25 μg/L ........ ∼4,000 N/A ∼4,000

1Estimates derive from actual system impacts projected in cost benefit analysis. Will differ from system-level figures discussed earlier in preamble. Reflect all systems having impacts, including those partially impacted.

Those systems whose current

source(s) will not meet the revised MCL

must either develop a new source,

install new treatment processes, or

enhance their existing treatment

processes. (The impact of developing a

new source are included in the analysis

of the new source requirement.) The

installation, operation, and maintenance

of new treatment technologies will

require a substantial enhancement of

these systems’ technical capacity.

Specifically, source water adequacy will

be reduced (marginal sources may no

longer be viable), the system will be

required to greatly enhance its

infrastructure (particularly its treatment

processes) to meet the technical

challenge posed by the revised MCL,

and system operators will require

correspondingly greater technical

expertise to successfully operate new

and more advanced treatment processes.

The impacts to the managerial

capacity of systems affected by the

revised arsenic MCL are not anticipated

to be as great as the technical and

financial challenges. Nonetheless, many

system managers will need to review the

implications of the revised MCL and

may need to hire a more highly certified

operator or provide additional training

for the existing operator.

In addition, systems will need to rely

upon and improve their interactions

with the service community and

technical/financial assistance providers.

System management will need to

explain the following issues: (1) The

reason why the arsenic standard was

revised, (2) the safety of the water that

the system provides, and (3) the reason

for new or higher fees. These activities

are in addition to the inclusion of the

health effects language in the CCR and

therefore will impact the managerial

capacity of a system.

The impacts of the arsenic rule

requirements to the technical capacity

of systems are closely tied to financial

impacts. Systems that must install

additional treatment processes or

upgrade their current treatment

processes may face significant costs.

These costs may be especially difficult

for many of the affected systems to

absorb since many of them are relatively

small (i.e., serving less than 3,300

customers), and therefore typically have

a smaller revenue base and fewer

households over which they may

distribute the additional costs. The rule

specifically allows the use of centrally

managed POU-treatment devices to

achieve compliance with the revised

arsenic MCL. However, the installation,

operation, maintenance, and

management of these devices still

represents a substantial expense for

small systems.

To obtain funding from either public

or private sources, systems will need to

demonstrate sound financial accounting

and budgeting practices, and the ability

to repay their debts. As a result, many

of the smallest systems that do not

currently charge explicitly for water

service (e.g., mobile home parks, camp

grounds, etc.) may need to begin to bill

their customers. Those systems that

already charge for water service will

likely need to increase their rates

(sometimes requiring approval of the

local public utilities commission

(PUC)), and improve their

recordkeeping procedures.

EPA anticipates that the revised

monitoring and reporting framework

will have a relatively limited impact on

system capacity even though some

CWSs will no longer be eligible for

reduced monitoring and others will no

longer be able to composite. NTNCWSs

will be required to monitor for arsenic

for the first time. To comply with this

requirement system management will

need to ensure that staff understand the

new requirements, that monitoring

records are properly maintained, and

that the appropriate reports are

provided to the State primacy agency

and EPA. In addition, systems will face

a slight increase in monitoring costs that

may require systems to adjust their

budgeting practices and fee structures.

Nonetheless, since most systems are

already familiar with the SMF for IOCs,

the impact to capacity is minimal.

There will be a substantial impact on

capacity for those systems that must

develop a new source to meet the

revised MCL. In addition to the

monitoring requirements specified in

the arsenic proposal, these systems will

expend substantial effort and money to

ensure that their new source(s) will

consistently provide reliable production

of high quality water.

Removing two currently approved

analytical methods should not have a

large impact on system capacity. Since

similarly priced alternative methods are

available, it was estimated that there

would be little to no impact to the

managerial and financial capacity of

systems that currently rely on this

method (or whose laboratory relies on

this method). A system may need to

ensure that the systems’ laboratory uses

an approved method and may need to

ensure that the operator is aware of the

change in approved analytical methods.

The requirement for affected systems

(those with arsenic levels above half the

revised MCL) to immediately begin

incorporating health affects language

into their CCRs will principally impact

the managerial capacity of systems.

Specifically, systems will need to: (1)

incorporate information about arsenic

into their CCRs; (2) explain to the

service community the reason why they

are including such information; (3)

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7055

explain the health implications of

current arsenic levels; and potentially,

(4) explain how the system anticipates

meeting the revised MCL. Moreover,

affected systems will also need to

prepare to respond to customer queries

regarding the new arsenic information

and the system’s compliance status.

The arsenic rule will have a

substantial impact on the capacity of the

4,100 CWSs and NTNCWSs that must

reduce arsenic levels or develop new

sources to meet the revised MCL.

However, while the impact to these

systems is significant, only five percent

of all systems regulated under the

Arsenic Rule (4,104 of 74,625) will be

affected by this requirement. The new

monitoring and reporting requirements,

removal of approved analytical

methods, and inclusion of health effects

language in the CCR are expected to

impact the capacity of approximately an

additional 26,000 systems to a small

degree. About 31,000 systems (i.e., 40%

of regulated systems) are expected to

experience minimal impact on their

capacity as a result of the arsenic rule.

VI. References

Agency for Toxic Substances and

Disease Registry. 1998. Draft

Toxicological Profile for Arsenic.

Prepared for the US Department of

Health and Human Services by the

Research Triangle Institute.

Albores, A., M.E. Cebrian, I. Tellez

and B. Valdez. 1979. Comparative Study

of Chronic Hydroarsenicism in Two

Rural Communities in the Region

Lagunra of Mexico. [in Spanish]. Bol.

Oficina Sanit. Panam. 86:196–205.

American Public Health Association

(APHA). 1992 and 1995. Standard

Methods for the Examination of Water

and Wastewater. 18th Edition, American

Public Health Association,1015

Fifteenth Street N.W., Washington, DC

20005.

American Society for Testing and

Materials (ASTM). 1994 and 1996.

Annual Book of ASTM Standards. Vol.

11.01 and 11.02, American Society for

Testing and Materials, 1916 Race Street,

Philadelphia, PA 19103.

Aposhian, H.V., E.S. Gurzau, X.C. Le,

A. Gurzau, S.H. Healy, X. Lu, M. Ma,

R.A. Zakharyan, R.M. Maiorino, R.C.

Dart, M.G. Tircus, D. Gonzalez-Remariz,

D.L. Morgan, D. Avram, D. and M.M.

Aposhian. 2000. Occurrence of

monomethylarsonous acid in urine of

humans exposed to inorganic arsenic.

Chemical Research Toxicology 13:693–

697.

Borgono, J.M, P. Vincent, H.

Venturino, and A. Infante. 1977. Arsenic

in the Drinking Water of the City of

Antofagasta: Epidemiological and

Clinical Study before and after the

Installation of a Treatment Plant.

Environmental Health Perspectives

19:103–105. August, 1997.

Borzsonyi, M., A. Berecsky, P.

Rudnai, M. Csanady and A. Horvath.

1992. Epidemiological Studies on

Human Subjects Exposed to Arsenic in

Drinking Water in Southeast Hungary.

Archives of Toxicology. 66:77–78.

Buchanan, W.D. 1962. Toxicity of

Arsenic Compounds. Amsterdam,

Elsevier Scientific Publishers. pp v–viii.

Buchet, J.P. and D. Lison. 1998.

Mortality by cancer in groups of the

Belgium population with a moderately

increases intake of arsenic. International

Archives Occupational Environmental

Health 71:125–130.

Carmignani, M., P. Boscolo and A.

Iannaccone. 1983. Effects of chronic

exposure to arsenate on the

cardiovascular function of rats. British

Journal Industrial Medicine 40:280–284.

Casale, R. and M. LeChevallier. 2000.

Contaminants in Drinking Water

Treatment Chemicals: A Survey of the

American Water Works System.

Proceedings American Water Works

Association Water Quality Technology

Conference. Salt Lake City, UT.

November 5–9.

Cebrian, M. 1987. Some Potential

Problems in Assessing the Effects of

Chronic Arsenic Exposure in North

Mexico [preprint extended abstract].

New Orleans, LA, American Chemical

Society.

Cebrian, M. E., A. Albores, M. Aguilar

and E. Blakely. 1983. Chronic Arsenic

Poisoning in the North of Mexico.

Human Toxicology. 2:121–133.

Chen, C.J., Y.C. Chuang, T.M. Lin, and

H.Y. Wu. 1985. Malignant neoplasms

among residents of a blackfoot diseaseendemic area in Taiwan: high arsenic

artesian well water and cancers. Cancer

Research. 45:5895–5899.

Chen, C.J., M., Wu, S.S. Lee, J.D.

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Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7059

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Number 24. February 4, 2000. Page

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17, 2000.

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10, 2000.

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May 2000.

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and Clarifications to Compliance and

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EEAC–00–013. July 27, 2000.

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and Clarifications to Compliance and

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DWC–1–001. December 12, 2000.

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Rule on the Technical, Managerial, and

Financial Capacity of Public Water

Systems. December 29, 2000.

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and Costs for the Removal of Arsenic

from Drinking Water. December 2000.

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Comments Document. December 2000.

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Largest Public Water Systems (With

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Arsenic Rule. December 29, 2000.

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Arsenic-Related Bladder and Lung

Cancer Mortality in Millard County,

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List of Subjects

40 CFR Part 9

Reporting and recordkeeping

requirements.

40 CFR Part 141

Environmental protection, Chemicals,

Indian lands, Incorporation by

reference, Intergovernmental relations,

Radiation protection, Reporting and

recordkeeping requirements, Water

supply.

40 CFR Part 142

Environmental protection,

Administrative practice and procedure,

Chemicals, Indian lands,

Intergovernmental relations, Radiation

protection, Reporting and recordkeeping

requirements, Water supply.

Dated: January 16, 2001.

Carol M. Browner,

Administrator.

For reasons stated in the preamble,

the Environmental Protection Agency

amends 40 CFR parts 9, 141 and 142 as

follows:

PART 9—OMB APPROVALS UNDER

THE PAPERWORK REDUCTION ACT

1. The authority citation for part 9

continues to read as follows:

Authority: 7 U.S.C. 135 et seq., 136–136y;

15 U.S.C. 2001, 2003, 2005, 2006, 2601–2671;

21 U.S.C. 331j, 346a, 348; 31 U.S.C. 9701; 33

U.S.C. 1251 et seq., 1311, 1313d, 1314, 1318,

1321, 1326–1330, 1324, 1344, 1345 (d) and

(e), 1361; E.O. 11735, 38 FR 21243, 3 CFR,

1971–1975 Comp. p. 973; 42 U.S.C. 241,

242b, 243, 246, 300f, 300g, 300g–1, 300g–2,

300g–3, 300g–4, 300g–5, 300g–6, 300j–1,

300j–2, 300j–3, 300j–4, 300j–9, 1857 et seq.,

6901–6992k, 7401–7671q, 7542, 9601–9657,

11023, 11048.

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7061

2. Amend the table in § 9.1 by

removing the entry for 141.23–141.24

and adding new entries for 141.23(a)–

(b), 141.23 (c), and 141.23(d)–141.24 to

read as follows:

§ 9.1 OMB approvals under the Paperwork

Reduction Act.

* * * * *

40 CFR citation OMB control

No.

*****

National Prmary Drinking Water Regulations

*****

141.23A(a)–(b) .......................... 2040–0090

141.23(c) ................................... 2040–0231

141.23(d)–141.24 ..................... 2040–0090

*****

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—[Amended]

§ 141.2 [Amended]

2. In 40 CFR 141.2 revise the

definition heading for ‘‘Point-of-entry

treatment device’’ to read ‘‘Point-ofentry treatment device (POE)’’, and

revise the definition heading for ‘‘Pointof-use treatment device’’ to read ‘‘Pointof-use treatment device (POU)’’.

3. Amend § 141.6 by revising

paragraphs (a) and (c), and adding

paragraphs (j) and (k) to read as follows:

§ 141.6 Effective dates.

(a) Except as provided in paragraphs

(b) through (k) of this section, and in

§ 141.80(a)(2), the regulations set forth

in this part shall take effect on June 24,

1977.

* * * * *

(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 maximum contaminant

levels (MCL) listed in § 141.62 is

effective for the purpose of compliance

on January 23, 2006.

Requirements relating to arsenic set

forth in §§ 141.23(i)(4), 141.23(k)(3)

introductory text, 141.23(k)(3)(ii),

141.51(b), 141.62(b), 141.62(b)(16),

141.62(c), 141.62(d), and 142.62(b)

revisions in Appendix A of subpart O

for the consumer confidence rule, and

Appendices A and B of subpart Q for

the public notification rule are effective

for the purpose of compliance on

January 23, 2006. However, the

consumer confidence rule reporting

requirements relating to arsenic listed in

§ 141.154(b) and (f) are effective for the

purpose of compliance on March 23,

2001.

(k) Regulations set forth in

§§ 141.23(i)(1), 141.23(i)(2),

141.24(f)(15), 141.24(f)(22),

141.24(h)(11), 141.24(h)(20), 142.16(e),

142.16(j), and 142.16(k) are effective for

the purpose of compliance on January

22, 2004.

Subpart B—[Amended]

4. Amend § 141.11 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.

(b) The maximum contaminant level

for arsenic is 0.05 milligrams per liter

for community water systems until

January 23, 2006.

* * * * *

Subpart C—[Amended]

5. Amend § 141.23 by:

a. Adding a new entry for ‘‘Arsenic’’

in alphabetical order to the table in

paragraph (a)(4)(i) and adding endnotes

6, 7 and 8,

b. Revising paragraphs (a)(5) and (c)

introductory text,

c. Adding paragraph (c)(9),

d. Revising paragraphs (f)(1), (i)(1),

and (i)(2),

e.–h. Adding paragraph (i)(4),

i. Revising the entries for arsenic in

the table in paragraph (k)(1),

j. Revising paragraph (k)(2)

introductory text,

k. Adding a new entry for ‘‘Arsenic’’

in alphabetical order to the table to

paragraph (k)(2) and revising footnote 1,

l. Revising the last sentence in

paragraph (k)(3) introductory text, and

m. Adding a new entry for ‘‘Arsenic’’

in alphabetical order 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) * * *

DETECTION LIMITS FOR INFORGANIC CONTAMINANTS

Contaminant MCL (mg/l) Methodology Detection Limit

(mg/l)

*******

Arsenic ................... 6 0.01 Atomic Absorption; Furnace .................................................................................................... 0.001

Atomic Absorption; Platform—Stabilized Temperature ........................................................... 7 0.0005

Atomic Absorption; Gaseous Hydride ..................................................................................... 0.001

ICP-Mass Spectrometry ........................................................................................................... 8 0.0014

*******

*****

6The value for arsenic is effective January 23, 2006. Unit then, the MCL is 0.05 mg/L.

7The MDL reported for EPA method 200.9 (Atomic Absorption; Platform—Stablized Temperature) was determined using a 2x concentration

step during sample digestion. The MDL determined for samples analyzed using direct analyses (i.e., no sample digestion) will be higher. Using

multiple depositions, EPA 200.9 is capable of obtaining MDL of 0.0001 mg/L. 8 Using selective ion monitoring, EPA Method 200.8 (ICP–MS) is capable of obtaining a MDL of 0.0001 mg/L.

* * * * *

(5) The frequency of monitoring for

asbestos shall be in accordance with

paragraph (b) of this section: the

frequency of monitoring for antimony,

arsenic, barium, beryllium, cadmium,

chromium, cyanide, fluoride, mercury,

nickel, selenium and thallium shall be

in accordance with paragraph (c) of this

section; the frequency of monitoring for

nitrate shall be in accordance with

paragraph (d) of this section; and the

7062 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

frequency of monitoring for nitrite shall

be in accordance with paragraph (e) of

this section.

* * * * *

(c) The frequency of monitoring

conducted to determine compliance

with the maximum contaminant levels

in § 141.62 for antimony, arsenic,

barium, beryllium, cadmium,

chromium, cyanide, fluoride, mercury,

nickel, selenium and thallium shall be

as follows:

* * * * *

(9) All new systems or systems that

use a new source of water that begin

operation after January 22, 2004 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.

* * * * *

(f) * * *

(1) Where the results of sampling for

antimony, arsenic, asbestos, barium,

beryllium, cadmium, chromium,

cyanide, fluoride, mercury, nickel,

selenium or thallium indicate an

exceedance of the maximum

contaminant level, the State may require

that one additional sample be collected

as soon as possible after the initial

sample was taken (but not to exceed two

weeks) at the same sampling point.

* * * * *

(i) * * *

(1) For systems which are conducting

monitoring at a frequency greater than

annual, compliance with the maximum

contaminant levels for antimony,

arsenic, asbestos, barium, beryllium,

cadmium, chromium, cyanide, fluoride,

mercury, nickel, selenium or thallium is

determined by a running annual average

at any sampling point. If the average at

any sampling point is greater than the

MCL, then the system is out of

compliance. If any one sample would

cause the annual average to be

exceeded, then the system is out of

compliance immediately. Any sample

below the method detection limit shall

be calculated at zero for the purpose of

determining the annual average. 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.

* * * * *

(4) 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:

Inductively Coupled Plasma 15 .................................................... 2 200.7 ........................ 15 3120B

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, PB

95–125472.

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. 15After January 23, 2006 analytical methods using the ICP–AES technology, may not be used because the detection limits for these methods

are 0.008 mg/L or higher. This restriction means that the two ICP–AES methods (EPA Method 200.7 and SM 3120 B) approved for use for the

MCL of 0.05 mg/L may not be used for compliance determinations for the revised MCL of 0.01 mg/L. However, prior to 2005 systems may have

compliance samples analyzed with these less sensitive methods.

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7063

* * * * *

(2) Sample collection for antimony,

arsenic, asbestos, barium, beryllium,

cadmium, chromium, cyanide, fluoride,

mercury, nickel, nitrate, nitrite,

selenium, and thallium under this

section shall be conducted using the

sample preservation, container, and

maximum holding time procedures

specified in the table below:

ContaminantPreservative 1Container 2 Time 3

*****

Arsenic Conc

HNO3 to

pH <2.

P or G 6 months

*****

1For cyanide determinations samples must

be adjusted with sodium hydroxide to pH 12 at

the time off collection. When chilling is indicated the sample must be shipped and stored

at 4°C or less. Acidification of nitrate or metals

samples may be with a concentrated acid or a

dilute (50% by volume) solution of the applicable concentrated acid. Acidification of samples

for metals analysis is encouraged and allowed

at the laboratory rather than at the time of

sampling provided the shipping time and other

instructions in Section 8.3 of EPA Methods

200.7 or 200.8 or 200.9 are followed. 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) * * * To receive certification to

conduct analyses for antimony, arsenic,

asbestos, barium, beryllium, cadmium,

chromium, cyanide, fluoride, mercury,

nickel, nitrate, nitrite and selenium and

thallium, the laboratory must:

* * * * *

(ii) * * *

Contaminant Acceptance limit

*****

Arsenic ............. ±30 at ≥0.003 mg/L

*****

* * * * *

6. Amend § 141.24 by:

a. Adding a new sentence to the end

of paragraph (f)(15) introductory text,

b. Revising paragraphs (f)(15)(i) and

(f)(15)(ii) and adding new paragraphs

(f)(15)(iii) through (f)(15)(v),

c. Adding paragraph (f)(22),

d. Adding a new sentence to the end

of paragraph (h)(11) introductory text,

e. Revising paragraphs (h)(11)(i) and

(h)(11)(ii) and adding new paragraphs

(h)(11)(iii) through (h)(11)(v), and

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) * * * If one sampling point is in

violation of an MCL, the system is in

violation of the MCL.

(i) For systems monitoring more than

once per year, compliance with the MCL

is determined by a running annual

average at each sampling point.

(ii) Systems monitoring annually or

less frequently whose sample result

exceeds the MCL must begin quarterly

sampling. The system will not be

considered in violation of the MCL until

it has completed one year of quarterly

sampling.

(iii) If any sample result will cause the

running annual average to exceed the

MCL at any sampling point, the system

is out of compliance with the MCL

immediately.

(iv) If a system fails to collect the

required number of samples,

compliance will be based on the total

number of samples collected.

(v) If a sample result is less than the

detection limit, zero will be used to

calculate the annual average.

* * * * *

(22) All new systems or systems that

use a new source of water that begin

operation after January 22, 2004 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)* * * If one sampling point is in

violation of an MCL, the system is in

violation of the MCL.

(i) For systems monitoring more than

once per year, compliance with the MCL

is determined by a running annual

average at each sampling point.

(ii) Systems monitoring annually or

less frequently whose sample result

exceeds the regulatory detection level as

defined by paragraph (h)(18) of this

section must begin quarterly sampling.

The system will not be considered in

violation of the MCL until it has

completed one year of quarterly

sampling.

(iii) If any sample result will cause the

running annual average to exceed the

MCL at any sampling point, the system

is out of compliance with the MCL

immediately.

(iv) If a system fails to collect the

required number of samples,

compliance will be based on the total

number of samples collected.

(v) If a sample result is less than the

detection limit, zero will be used to

calculate the annual average.

* * * * *

(20) All new systems or systems that

use a new source of water that begin

operation after January 22, 2004 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. Amend the table in § 141.51(b) by

adding a new entry for ‘‘Arsenic’’ in

alphabetical order and adding a new

endnote to read as follows:

§ 141.51 Maximum contaminant level goals

for inorganic contaminants.

* * * * *

(b) * * *

Contaminant MCLG (mg/L)

*****

Arsenic .......................... zero 1

* * * **

1This value for arsenic is effective January

23, 2006. Until then, there is no MCLG.

Subpart G—[Amended]

8. Amend § 141.60 by adding

paragraph (b)(4) to read as follows:

§ 141.60 Effective dates.

* * * * *

(b) * * *

(4) The effective date for

§ 141.62(b)(16) is January 23, 2006.

9. Amend § 141.62 by:

a. Revising the first sentence of

paragraph (b) introductory text,

b. Adding a new entry ‘‘(16)’’ for

arsenic to the table in paragraph (b),

c. Adding a new entry for ‘‘Arsenic’’

in alphabetical order, adding new

endnotes 4 and 5, adding a new item 12

and revising items 2 and 6 to list of

‘‘Key to BATs in Table’’ and revising the

heading to the table in paragraph (c),

d. Adding paragraph (d).

The revisions and additions read as

follows:

§ 141.62 Maximum Contaminant Levels for

inorganic contaminants.

* * * * *

(b) The maximum contaminant levels

for inorganic contaminants specified in

7064 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

paragraphs (b) (2)–(6), (b)(10), and (b)

(11)–(16) of this section apply to

community water systems and nontransient, non-community water

systems. * * *

* * * * *

Contaminant MCL (mg/L)

*****

(16) Arsenic ................... 0.01

(c) * * *

BAT FOR INORGANIC COMPOUNDS LISTED IN SECTION

141.62(B)

Chemical Name BAT(s)

*****

Arsenic 4 ........................ 1, 2, 5, 6, 7, 9, 12 5

*****

*****

4BATs for Arsenic V. Pre-oxidation may be

required to convert Arsenic III to Arsenic V. 5To obtain high removals, iron to arsenic

ratio must be at least 20:1.

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

* * * * *

12 = Oxidation/Filtration

* * * * *

(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-Use) 4 ........................................................... All size categories.

Coagulation/Filtration 5 .............................................................................. 501–3,300, 3,301–10,000.

Coagulation-assisted Microfiltration .......................................................... 501–3,300, 3,301–10,000.

Electrodialysis reversal 6 ........................................................................... 501–3,300, 3,301–10,000.

Enhanced coagulation/filtration ................................................................ All size categories

Enhanced lime softening (pH> 10.5) ........................................................ All size categories.

Ion Exchange ............................................................................................ All size categories.

Lime Softening 5 ....................................................................................... 501–3,300, 3,301–10,000.

Oxidation/Filtration 7 .................................................................................. All size categories.

Reverse Osmosis (centralized) 6 .............................................................. 501–3,300, 3,301–10,000.

Reverse Osmosis (Point-of-Use) 4 ........................................................... All size categories.

1Section 1412(b)(4)(E)(ii) of 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. 5 Unlikely to be installed solely for arsenic removal. May require pH adjustment to optimal range if high removals are needed.

6Technologies reject a large volume of water—may not be appropriate for areas where water quantity may be an issue. 7To obtain high removals, iron to arsenic ratio must be at least 20:1.

Subpart O—[Amended]

10. Amend § 141.154 by revising

paragraph (b) and adding paragraph (f)

to read as follows:

§ 141.154 Required additional health

information.

* * * * *

(b) Ending in the report due by July

1, 2001, a system which detects arsenic

at levels above 0.025 mg/L, but below

the 0.05 mg/L, and beginning in the

report due by July 1, 2002, a system that

detects arsenic above 0.005 mg/L and up

to and including 0.01 mg/L:

(1) Must include in its report a short

informational statement about arsenic,

using language such as: While your

drinking water meets EPA’s standard for

arsenic, it does contain low levels of

arsenic. EPA’s standard balances the

current understanding of arsenic’s

possible health effects against the costs

of removing arsenic from drinking

water. EPA continues to research the

health effects of low levels of arsenic,

which is a mineral known to cause

cancer in humans at high concentrations

and is linked to other health effects such

as skin damage and circulatory

problems.

(2) May write its own educational

statement, but only in consultation with

the Primacy Agency.

* * * * *

(f) Beginning in the report due by July

1, 2002 and ending January 22, 2006, a

community water system that detects

arsenic above 0.01 mg/L and up to and

including 0.05 mg/L must include the

arsenic health effects language

prescribed by Appendix A to Subpart O.

11. Amend Appendix A to Subpart O

by revising the entry for arsenic under

‘‘Inorganic contaminants:’’ and adding

an endnote to read as follows:

Appendix A to Subpart O—Regulated

Contaminants

Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations 7065

Contaminant

(units)

Traditional

MCL

in mg/L

To

convert

for

CCR,

multiply

by

MCL in

CCR units MCLG

Major Sources

in

drinking water

Health effects language

*******

Inorganic contaminants:

*******

Arsenic (ppb) .............. 1 0.01 1000 1 10 1 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.

*******

* * * * *

1. These arsenic values are effective

January 23, 2006. Until then, the MCL is 0.05

mg/L and there is no MCLG.

Subpart Q—[Amended]

12. Amend Appendix A to Subpart Q

by:

a. Revising the entry for ‘‘2. Arsenic’’

under ‘‘B. Inorganic Chemicals (IOCs)’’,

b. Redesignating endnotes 8 through

17 as endnotes 10 through 19 in the

table and at the end of the table, and

c. Adding endnotes 8 and 9.

The revisions and additions read as

follows:

Appendix A to Subpart Q—NPDWR

Violations and Other Situations

Requiring Public Notice 1

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 8 141.62(b) 3 9 141.23(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.

* * * * *

8. The arsenic MCL citations are effective

January 23, 2006. Until then, the citations are

§ 141.11(b) and § 141.23(n).

9. The arsenic Tier 3 violation MCL

citations are effective January 23, 2006. Until

then, the citations are § 141.23(a), (l).

* * * * *

13. Amend Appendix B to Subpart Q

by:

a. Revising entry ‘‘9. Arsenic’’ under

‘‘C. Inorganic chemicals (IOCs)’’,

b. Redesignating endnotes 11 through

21 as endnotes 12 through 22 in the

table and at the end of the table, and

c. Adding endnote 11.

The revisions and additions read as

follows:

Appendix B to Subpart Q—Standard

Health Effects Language for Public

Notification

Contaminant MCLG 1 mg/L MCL 2 mg/L Standard health effects language for public notification

*******

9. Arsenic 11 ...................................... 0 0.01 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.

7066 Federal Register / Vol. 66, No. 14 / Monday, January 22, 2001 / Rules and Regulations

Contaminant MCLG 1 mg/L MCL 2 mg/L Standard health effects language for public notification

*******

Appendix B—Endnotes

1. MCLG–Maximum contaminant level

goal.

2. MCL–Maximum contaminant level.

* * * * *

11. These arsenic values are effective

January 23, 2006. Until then, the MCL is 0.05

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—[Amended]

2. Amend § 142.16 by revising

paragraph (e) introductory text,

reserving paragraph (i), and adding

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, 141.32, 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):

* * * * *

(i) [reserved]

(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

paragraph (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 16(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 ensure all systems complete

the required monitoring by 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 16(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 comply with MCL’s

and monitoring requirements. States

must also specify the time frame in

which new systems will demonstrate

compliance with the MCLs.

3. Amend the table in § 142.62(b) by

adding a new entry for ‘‘Arsenic’’ in

alphabetical order, adding new

endnotes 4 and 5, adding a new item 12

to list of ‘‘Keys to BATs in Table’’ and

revising the heading to the table in

paragraph (b) 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)

Chemical name BAT(s)

*****

Arsenic 4 ............ 5 1, 2, 5, 6, 7, 9, 12

*****

*****

4BATs for Arsenic V. Pre-oxidation may be

required to convert Arsenic III to Arsenic V. 5To obtain high removals, iron to arsenic

ratio must be at least 20:1.

* * * * *

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

* * * * *

12 = Oxidation/Filtration

* * * * *

[FR Doc. 01–1668 Filed 1–19–01; 8:45 am]

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