federal register

Tuesday

November 2, 1999

Part II

Environmental

Protection Agency

40 CFR Parts 141 and 142

National Primary Drinking Water

Regulations; Radon-222; Proposed Rule
59246 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Parts 141 and 142

[WH–FRL–6462–8]

RIN 2040–AA94

National Primary Drinking Water

Regulations; Radon-222

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Notice of proposed rulemaking.

SUMMARY: In this action, the

Environmental Protection Agency (EPA)

is proposing a multimedia approach to

reducing radon risks in indoor air

(where the problem is greatest), while

protecting public health from the

highest levels of radon in drinking

water. Most radon enters indoor air from

soil under homes and other buildings.

Only approximately 1–2 percent comes

from drinking water. The Agency is

proposing a Maximum Contaminant

Level Goal (MCLG) and National

Primary Drinking Water Regulations

(NPDWR) for radon-222 in public water

supplies. Under the framework set forth

in the 1996 amendments to the SDWA,

EPA is also proposing an alternative

maximum contaminant level (AMCL)

and requirements for multimedia

mitigation (MMM) programs to address

radon in indoor air. Public water

systems (PWS) are defined in the Safe

Drinking Water Act (SDWA). This

proposed rule applies to community

water systems (CWS), a subset of PWSs.

Under the proposed rule, CWSs may

comply with the AMCL if they are in

States that develop an EPA-approved

MMM program or, in the absence of a

State program, develop a State-approved

CWS MMM program. This approach is

intended to encourage States, Tribes,

and CWSs to reduce the health risk of

radon in the most cost-effective way.

The Agency is also proposing a

maximum contaminant level (MCL) for

radon-222, to apply to CWSs in nonMMM States that choose not to

implement a CWS MMM program. The

proposal also includes monitoring,

reporting, public notification, and

consumer confidence report

requirements for radon-222 in drinking

water.

DATES: EPA must receive public

comments, in writing, on the proposed

regulations by January 3, 2000.

ADDRESSES: You may send written

comments to the Radon-222, W–99–08

Comments Clerk, Water Docket (MC–

4101); U.S. Environmental Protection

Agency; 401 M Street, SW., Washington,

DC 20460. Comments may be handdelivered to the Water Docket, U.S.

Environmental Protection Agency; 401

M Street, SW., East Tower Basement,

Washington, DC 20460. Comments may

be submitted electronically to

owdocket@epamail.epa.gov. Electronic

comments must be submitted as an

ASCII, WP6.1, or WP8 file avoiding the

use of special characters and any form

of encryption. Electronic comments

must be identified by the docket number

W–99–08. Comments and data will also

be accepted on disks in WP6.1, WP8, or

ASCII format. Electronic comments on

this action may be filed online at many

Federal Depository libraries.

Please submit a copy of any references

cited in your comments. Facsimiles

(faxes) cannot be accepted. EPA would

appreciate one original and three copies

of your comments and enclosures

(including any references). Commenters

who would like EPA to acknowledge

receipt of their comments should

include a self-addressed, stamped

envelope.

The proposed rule and supporting

documents, including public comments,

are available for review in the Water

Docket at the address listed previously.

The Docket also has several of the key

supporting documents electronically

available as PDF files. For information

on how to access Docket materials,

please call (202) 260–3027 between 9

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

Monday through Friday.

FOR FURTHER INFORMATION CONTACT: For

general information on radon in

drinking water, contact the Safe

Drinking Water Hotline, phone (800)

426–4791. The Safe Drinking Water

Hotline is open Monday through Friday,

excluding Federal holidays, from 9 a.m.

to 5:30 p.m. Eastern Time. For technical

inquiries regarding the proposed

regulations, contact Sylvia Malm, Office

of Ground Water and Drinking Water,

U.S. Environmental Protection Agency

(mailcode 4607), 401 M Street, SW,

Washington DC, 20460. Phone: (202)

260–0417. E-mail:

malm.sylvia@epa.gov. For inquiries

regarding the proposed multimedia

mitigation program, contact Anita

Schmidt, Office of Radiation and Indoor

Air, U.S. Environmental Protection

Agency, (mailcode 6609J), 401 M Street,

S.W, Washington, DC, 20460. Phone:

(202) 564–9452. E-mail:

schmidt.anita@epa.gov. For general

information on radon in indoor air,

contact the Radon Hotline at 1–800–

SOS–RADON (1–800–767–7236).

SUPPLEMENTARY INFORMATION:

Potentially Regulated Entities

Potentially regulated entities include

community water systems using ground

water or mixed ground and surface

water.

The following table lists potentially

regulated entities. This 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 of that

could potentially be regulated by this

action. Other entities not listed in the

table could also be regulated. To

determine whether your organization is

affected by this action, you should

carefully examine the proposed

applicability criteria in section 40 CFR

parts 141.20(b)(1) and Section IV of the

preamble. If you have questions

regarding the applicability of this action

to a particular entity, consult Sylvia

Malm who is listed in the preceding FOR

FURTHER INFORMATION CONTACT section.

Category Examples of potentially regulated entities

Industry .......... Privately owned/operated

community water supply

systems using ground

water or mixed ground

water and surface water.

State, Tribal,

and Local

Government.

State, Tribal, or local government-owned/operated

water supply systems

using ground water or

mixed ground water and

surface water.

Federal Government.Federally owned/operated

community water supply

systems using ground

water or mixed ground

water and surface water.

Abbreviations Used in This Proposal

AMCL: Alternative Maximum

Contaminant Level

BAT: Best Available Technology

BEIR: Committee on the Biological

Effects of Ionizing Radiation. The

Committee on Health Risks of

Exposure on Radon that conducted

the National Research Council

Biological Effects of Ionizing

Radiation (BEIR) VI Study (NAS

1999a). The committee is formed by

the Radiation Effect Research/

Commission on Life Sciences/

National Research Council/National

Academy of Sciences.

CFR: Code of Federal Regulations

CWS: Community Water System

EF: Equilibrium Factor

EPA: U.S. Environmental Protection

Agency

FR: Federal Register

GAC: Granular Activated Carbon
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59247

HRRCA: Health Risk Reduction and

Cost Analysis

IOC: Inorganic Contaminant

LSC: Liquid Scintillation Counting

MCL: Maximum Contaminant Level

MCLG: Maximum Contaminant Level

Goal

MMM: Multimedia Mitigation

NAS: National Academy of Sciences

NAS Radon in Drinking Water

Committee: The Committee on Risk

Assessment of Exposure to Radon of

the Drinking Water that conducted the

National Research Council Risk

Assessment of Radon in Drinking

Water Study (NAS 1999b). The

committee is formed by the Board of

Radiation Effect Research of the

Commission on Life Sciences of the

National Research Council, National

Academy of Sciences.

NELAC: National Environmental

Laboratory Accreditation Conference

NIST: National Institute of Standards

and Technology

NIRS: National Inorganics and

Radionuclides Survey

NPDWR: National Primary Drinking

Water Regulation

NPRM: Notice of Proposed Rulemaking

NTNC: Non-Transient, Non-Community

OGWDW: Office of Ground Water and

Drinking Water

OMB: Office of Management and Budget

PBMS: Performance-Based

Measurement System

PE: Performance Evaluation

PT: Proficiency Testing

POE: Point-of-Entry

POU: Point-of-Use

PRA: Paperwork Reduction Act

PWS: Public Water System

pCi/L: Picocuries per Liter

RFA: Regulatory Flexibility Act

SAB: Science Advisory Board

SBA: Small Business Administration

SBO: Small Business Ombudsman

SBREFA: Small Business Regulatory

Enforcement and Fairness Act

SDWA: Safe Drinking Water Act

SDWIS: Safe Drinking Water

Information System

SIRG: State Indoor Radon Grant

SSCT: Small Systems Compliance

Technology

SSVT: Small Systems Variance

Technology

SMF: Standardized Monitoring

Framework

UMRA: Unfunded Mandates Reform Act

URTH: Unreasonable Risks to Health

WL: Working Level

WLM: Working Level Month

Table of Contents

I. Summary: What Does Today’s Proposed

Rulemaking Mean for My Water System?

A. Why is EPA Proposing to Regulate

Radon in Drinking Water?

B. What is Radon?

C. What are the Health Concerns from

Radon in Air and Water?

D. Does this Regulation Apply to My Water

System?

E. How Will this Regulation Protect Public

Health?

F. How Will the Multimedia Mitigation

(MMM) Program Work?

G. What are the Proposed Limits for Radon

in Drinking Water?

H. What is the Proposed Best Available

Technology (BAT) for Treating Radon in

Drinking Water?

I. What Analytical Methods are

Recommended?

J. Where and How Often Must I Test My

Water for Radon?

K. May I Use Point-of-Use (POU) Devices,

Point-of-Entry (POE) Devices, or Bottled

Water to Comply with this Regulation?

L. May I Get More Time or Use a Cheaper

Treatment? Variances and Exemptions

M. What are State Primacy, Record

Keeping, and Reporting Requirements?

N. How are Tribes Treated in this

Proposal?

Statutory Requirements and Regulatory

History

II. What Does the Safe Drinking Water Act

Require the EPA to Do When Regulating

Radon in Drinking Water?

A. Withdraw the 1991 Proposed Regulation

for Radon

B. Arrange for a National Academy of

Sciences Risk Assessment.

C. Set an MCLG, MCL, and BAT for Radon222

D. Set an Alternative MCL (AMCL) and

Develop Multimedia Mitigation (MMM)

Program Plan Criteria

E. Evaluate Multimedia Mitigation

Programs Every Five Years

III. What Actions Has EPA Taken on Radon

in Drinking Water Prior to This

Proposal?

A. Regulatory Actions Prior to 1991

B. The 1991 NPRM

C. 1994 Report to Congress: Multimedia

Risk and Cost Assessment of Radon

D. 1997 Withdrawal of the 1991 NPRM for

Radon-222

E. 1998 SBREFA Small Business Advocacy

Review Panel for Radon

F. 1999 HRRCA for Radon in Drinking

Water

Requirements

IV. To Which Water Systems Does this

Regulation Apply?

V. What is the Proposed Maximum

Contaminant Level Goal (MCLG) for

Radon?

A. Approach to Setting the MCLG

B. MCLG for Radon in Drinking Water

VI. What Must a State or Community Water

System Have In Its Multimedia

Mitigation Program Plan?

A. What are the Criteria?

B. Why Will MMM Programs Get Risk

Reduction Equal or Greater Than

Compliance with the MCL?

C. Implementation of an MMM Program in

Non-Primacy States

D. Implementation of the MMM Program in

Indian Country

E. CWS Role in State MMM Programs

F. Local CWS MMM Programs in NonMMM States and State Role in Approval

of CWS MMM Program Plans

G. CWS Role in Communicating to

Customers

H. How Did EPA Develop These Criteria?

I. Background on the Existing EPA and

State Indoor Radon Programs

VII. What are the Requirements for

Addressing Radon in Water and Radon

in Air? MCL, AMCL and MMM

A. Requirements for Small Systems Serving

10,000 People or Less

B. Requirements for Large Systems Serving

More Than 10,000 People

C. State Role in Approval of CWS MMM

Program Plans

D. Background on Selection of MCL and

AMCL

E. Compliance Dates

VIII. What are the Requirements for Testing

for and Treating Radon in Drinking

Water?

A. Best Available Technologies (BATs),

Small Systems Compliance Technologies

(SSCTs), and Associated Costs

B. Analytical Methods

C. Laboratory Approval and Certification

D. Performance-Based Measurement

System (PBMS)

E. Proposed Monitoring and Compliance

Requirements for Radon

IX. State Implementation

A. Special State Primacy Requirements

B. State Record Keeping Requirements

C. State Reporting Requirements

D. Variances and Exemptions

E. Withdrawing Approval of a State MMM

Program

X. What Do I Need to Tell My Customers?

Public Information Requirements

A. Public Notification

B. Consumer Confidence Report

Risk Assessment and Occurrence

XI. What is EPA’s Estimate of the Levels of

Radon in Drinking Water?

A. General Patterns of Radon Occurrence

B. Past Studies of Radon Levels in Drinking

Water

C. EPA’s Most Recent Studies of Radon

Levels in Ground Water

D. Populations Exposed to Radon in

Drinking Water

XII. What Are the Risks of Radon in Drinking

Water and Air?

A. Basis for Health Concern

B. Previous EPA Risk Assessment of Radon

in Drinking Water

C. NAS Risk Assessment of Radon in

Drinking Water

D. Estimated Individual and Population

Risks

E. Assessment by National Academy of

Sciences: Multimedia Approach to Risk

Reduction

Economics and Impacts Analysis

XIII. What is the EPA’s Estimate of National

Economic Impacts and Benefits?

A. Safe Drinking Water Act (SDWA)

Requirements for the HRRCA

B. Regulatory Impact Analysis and Revised

Health Risk Reduction and Cost Analysis

(HRRCA) for Radon
59248 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

C. Baseline Analysis

D. Benefits Analysis

E. Cost Analysis

F. Economic Impact Analysis

G. Weighing the Benefits and Costs

H. Response to Significant Public

Comments on the February 1999 HRRCA

XIV. Administrative Requirements

A. Executive Order 12866: Regulatory

Planning and Review

B. Regulatory Flexibility Act (RFA)

C. Unfunded Mandates Reform Act

(UMRA)

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 on Federalism

I. Executive Order 13084: Consultation and

Coordination with Indian Tribal

Governments

J. Request for Comments on Use of Plain

Language

Stakeholder Involvement

XV. How has the EPA Provided Information

to Stakeholders in Development of this

NPRM?

A. Office of Ground Water and Drinking

Water Website

B. Public Meetings

C. Small Entity Outreach

D. Environmental Justice Initiatives

E. AWWA Radon Technical Work Group

Background

XVI. How Does EPA Develop Regulations to

Protect Drinking Water?

A. Setting Maximum Contaminant Level

Goal and Maximum Contaminant Level

B. Identifying Best Available Treatment

Technology

C. Identifying Affordable Treatment

Technologies for Small Systems

D. Requirements for Monitoring, Quality

Control, and Record Keeping

E. Requirements for Water Systems to

Notify Customers of Test Results if Not

in Compliance

F. Approval of State Drinking Water

Programs to Enforce Federal Regulations

XVII. Important Technical Terms

XVIII. References

Appendix I to the Preamble: What are the

Major Public Comments on the 1991 NPRM

and How has the EPA Addressed Them in

this Proposal?

A. General Issues

B. Statutory Authority and Requirements

C. Radon Occurrence

D. Radon Exposure and Health Effects

E. Maximum Contaminant Level

F. Analytical Methods

G. Treatment Technologies and Cost

H. Compliance Monitoring

I. Summary: What Does Today’s

Proposed Rulemaking Mean for My

Water System?

A. Why Is EPA Proposing To Regulate

Radon in Drinking Water?

The proposed National Primary

Drinking Water Regulation (NPDWR) for

radon in drinking water is based on a

multimedia approach designed to

achieve greater risk reduction by

addressing radon risks in indoor air,

with public water systems providing

protection from the highest levels of

radon in their ground water supplies.

The framework for this proposal is set

out in the Safe Drinking Water Act as

amended in 1996 (SDWA), which

provides for a multimedia approach for

addressing the public health risks from

radon in drinking water and radon in

indoor air from soil. This statutorybased framework reflects the

characteristics uniquely specific to

radon among drinking water

contaminants: that the relative costeffectiveness of reducing risk from

exposure to this contaminant is

substantially greater for a non-drinking

water source of exposure—indoor air—

than it is from drinking water.

Accordingly, SDWA directs the

Environmental Protection Agency (EPA)

to promulgate a maximum contaminant

level (MCL) for radon in drinking water,

but also to make available a higher

alternative maximum contaminant level

(AMCL) accompanied by a multimedia

mitigation (MMM) program to address

radon risks in indoor air. Further, in

setting the MCL, EPA is to take into

account the costs and benefits of

programs that control radon in indoor

air (SDWA 1412(b)(13)(E)).

B. What Is Radon?

Radon’s Physical Properties

Throughout this preamble, ‘‘radon’’

refers to the specific isotope radon-222.

Radon is a naturally occurring gas

formed from the radioactive decay of

uranium-238. Low concentrations of

uranium and its other decay products,

specifically radium-226, occur widely in

the earth’s crust, and thus radon is

continually being generated, even in

soils in which there is no man-made

radioactive contamination. Radon is

colorless, odorless, tasteless, chemically

inert, and radioactive. A portion of the

radon released through radioactive

decay moves through air or water-filled

pores in the soil to the soil surface and

enters the air, while some remains

below the surface and dissolves in

ground water (water that collects and

flows under the ground’s surface).

Because radon is a gas, when water

that contains radon is exposed to the air,

the radon will tend to be released into

the air. Therefore, radon is usually

present in only low amounts in rivers

and lakes. If ground water is supplied to

a house, radon in the water will tend to

be released into the air of the house via

various water uses. Thus presence of

radon in drinking water supplies leads

to exposure via both oral route

(ingesting water containing radon) and

inhalation route (breathing air

containing both radon and radon decay

products released from water used in

the house such as for cooking and

washing).

Radon itself also decays, emitting

ionizing radiation in the form of alpha

particles, and transforms into decay

products, or ‘‘progeny’’ radioisotopes. It

has a half-life of about four days and

decays into short-lived progeny. Unlike

radon, the progeny are not gases, and

can easily attach to and be transported

by dust and other particles in air. The

decay of progeny continues until stable,

non-radioactive progeny are formed. At

each step in the decay process, radiation

is released.

C. What Are the Health Concerns From

Radon in Air and Water?

National and international scientific

organizations have concluded that

radon causes lung cancer in humans.

The primary risk is lung cancer from

radon entering indoor air from soil

under homes. Tap water is a smaller

source of radon in air; however,

breathing radon released to air from

household water uses also increases the

risk of lung cancer, and consumption of

drinking water containing radon

presents a smaller risk of internal organ

cancers, primarily stomach cancer.

In most cases, radon in soil under

homes is the biggest source of exposure

and radon from tap water will be a small

source of radon in indoor air.

The U.S. Surgeon General has warned

that indoor radon (from soil) is the

second leading cause of lung cancer

(USEPA 1988b). The National Academy

of Sciences (NAS 1999a) estimates that

radon from soil causes about 15,000 to

22,000 (using two different approaches)

lung cancer deaths each year in the U.S.

If you smoke and your home has high

indoor radon levels, your risk of lung

cancer is especially high. EPA and the

U.S. Surgeon General recommend

testing all homes below the third floor.

The NAS report mandated by the

1996 SDWA identifies the same unit

risk associated with radon in drinking

water compared with previous EPA

analyses. Based on the NAS risk

assessment and an updated EPA
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59249

occurrence analysis, the Agency

estimates that uncontrolled levels of

radon in public drinking water supplies

cause 168 fatal cancers each year in the

U.S. However, radon in domestic

drinking water generally contributes a

very small part (about 1–2 percent) of

total radon exposure from indoor air.

The NAS estimated that about 89

percent of the fatal cancers caused by

radon in drinking water were due to

lung cancer from inhalation of radon

released to indoor air, and about 11

percent were due to stomach cancer

from consuming water containing radon

(NAS 1999b).

D. Does This Regulation Apply to My

Water System?

The regulation for radon in drinking

water and the multimedia approach

proposed in this action would apply to

all community public water systems

(CWSs) that use ground water or mixed

ground and surface water. The proposed

regulation would not apply to nontransient non-community (NTNC)

public water supplies, nor to transient

public water supplies.

E. How Will This Regulation Protect

Public Health?

Given the much greater potential for

risk reduction in indoor air and years of

experience with radon mitigation

programs, EPA expects that greater

overall risk reduction will result from

this proposal than from an approach

which solely addresses radon in public

drinking water supplies. The proposed

regulation for radon in drinking water is

intended to promote a more costeffective multimedia approach to reduce

radon risks, particularly for small

systems with limited resources, and to

reduce the highest levels of radon in

drinking water. This determination to

have a strong and effective multimedia

radon program to address radon in

indoor air is consistent with the SDWA

framework for multimedia radon

programs and the SDWA expectation

that EPA would give significant weight

to the risk findings of the NAS report,

which confirm the health risks of radon

in drinking water, and the much greater

risks from radon in indoor air arising

from soil under homes.

F. How Will the Multimedia Mitigation

(MMM) Program Work?

The multimedia mitigation (MMM)

program is modeled on the National

Indoor Radon Program implemented by

EPA, States and others. That program

has achieved substantial risk reduction

through voluntary public action since

the release of the original ‘‘A Citizen’s

Guide to Radon’’ in 1986 (USEPA 1986,

1992b) and the U.S. Surgeon General’s

recommendation in 1988 that all homes

be tested and elevated levels be

reduced. The program has been

successful in achieving indoor radon

risk reduction through a variety of

program strategies, which form the basis

for EPA’s proposed multimedia

mitigation program plan criteria. Based

on the estimated number of existing

homes fixed and the number of new

homes built radon-resistant since the

national program began in 1986, EPA

estimates that under existing Federal

and State indoor radon programs, a total

of more than 2,500 lives will be saved

through indoor radon risk reduction

efforts expected to take place through

the year 2000. Every year the rate of

lives saved increases as more existing

houses with elevated radon levels are

fixed and as more new houses are built

radon-resistant. For the year 2000, EPA

estimates that the rate of radon-related

lung cancer deaths that will be avoided

from mitigation of existing homes and

from homes built radon-resistant (in

high radon areas) will be about 350 lives

saved per year (USEPA 1999i).

The MMM/AMCL approach is

intended to provide a more costeffective alternative to achieve radon

risk reduction, by allowing States (or

community water systems) to address

radon in indoor air from the soil source,

while reducing the highest levels of

radon in drinking water. It is EPA’s

expectation that most States will

develop State-wide multimedia

mitigation programs as the most costeffective approach. Most of the States

currently have indoor radon programs

that are addressing radon risk from soil,

and can be used as the foundation for

development of MMM program plans.

EPA expects that State indoor radon

programs will implement MMM

programs under agreements with the

State drinking water programs. The

regulatory expectation of community

water systems serving 10,000 persons or

less is that they meet the alternative

maximum contaminant level (AMCL)

and be associated with an approved

MMM program plan—either developed

by the State and approved by EPA or

developed by the CWS and approved by

the State. Tribal CWS MMM programs,

as well as those in States and Territories

that do not have drinking water

primacy, will be approved by EPA. The

same general criteria for State MMM

program plans would apply to CWSs in

developing local MMM programs in

States that do not have such a program,

albeit with a local perspective on such

criteria and commensurate with the

unique attributes of small CWSs. EPA

expects that MMM program strategies

for CWSs will be less comprehensive

than those of State MMM programs, and

will need to reflect the local character

of the community served by the CWS.

Strong public participation in the

development of the CWS MMM program

plans will help to ensure this, as well

as community support for the MMM

program. Figures I.1 and I.2 provide a

conceptual model for the MCL, AMCL,

and MMM programs for small and large

systems.

BILLING CODE 6560–50–P
59250 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59251

BILLING CODE 6560–50–C
59252 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

To meet the requirements of SDWA,

the risk reduction benefits expected to

be achieved by MMM programs are to be

equal to or greater than risk reduction

benefits that would be achieved by

CWSs complying with the MCL. Under

SDWA, this means that if all States

implemented MMM programs they

would be expected to result in about 62

cancer deaths averted annually, equal to

what would be achieved with universal

compliance with the MCL at 300 pCi/L.

Unlike health risk reduction benefits

gained through water treatment, which

remain constant from one year to the

next, the rate of health benefits from

reducing indoor radon is cumulative;

that is, it steadily increases every year

with every additional existing home that

is mitigated and with every new home

built radon-resistant. Therefore, MMM

programs will use and build on the

indoor radon program framework to

achieve ‘‘equal or greater’’ risk

reduction, rather than focusing efforts

on precisely quantifying ‘‘equivalency’’

to the much more limited risk reduction

expected to occur if community water

systems complied with the MCL.

G. What Are the Proposed Limits for

Radon in Drinking Water?

The proposed regulation provides that

States may adopt State-wide MMM

programs and the alternative maximum

contaminant level (AMCL) of 4000 pCi/

L. This is the most effective approach

for radon risk reduction and the one

EPA expects the majority of States to

adopt. If a State has an EPA-approved

MMM program plan, CWSs in that State

may comply with the AMCL. In the

absence of an approved State MMM

program plan the regulatory expectation

for small CWSs (those serving 10,000 or

fewer) is that they comply with a level

of 4000 pCi/L in drinking water, and

develop and implement a Stateapproved local MMM program plan to

reduce indoor radon risks arising from

soil and rock under homes and

buildings. Small CWSs may also choose

to comply with the MCL of 300 pCi/L

(and not develop a local MMM

program.)

The AMCL/MMM approach is EPA’s

regulatory expectation for small CWSs

because an MMM program and

compliance with the AMCL is a much

more cost-effective way to reduce radon

risk than compliance with the

maximum contaminant level (MCL) of

300 pCi/L. (While EPA believes that the

MMM approach is preferable for small

systems in a non-MMM State, small

CWSs may, at their discretion, choose

the option of meeting the MCL instead

of developing a local MMM program).

Large CWSs (serving a population of

more than 10,000) must either comply

with the proposed MCL or comply with

the AMCL and implement a Stateapproved CWS MMM program plan (in

the absence of an approved State MMM

program plan).

If a State has an approved MMM

program plan, the standard for radon in

drinking water that the State would

adopt in order to obtain primacy would

be 4000 pCi/L.

Under the proposed requirements, an

MMM program plan must address four

criteria:

1. Public involvement in development

of the MMM program plan

2. Quantitative goals for existing homes

fixed and new homes built radonresistant

3. Strategies for achieving goals

4. Plan to track and report results

CWSs must monitor for radon in

drinking water according to the

requirements described in Section VIII

of this preamble, and report their results

to the State. If the State determines that

the radon level in a CWS is below 300

pCi/L, the system need only continue to

meet monitoring requirements and is

not covered by the requirements

described in Section VI of this

preamble, regarding MMM programs.

H. What Is the Proposed Best Available

Technology (BAT) for Treating Radon in

Drinking Water?

Proposed BAT for Radon Under Section

1412 of the SDWA

High-performance aeration, as

described in Section VIII.A of this

preamble, is the BAT for all systems.

For systems serving 10,000 persons or

fewer, the BAT is high-performance

aeration and the Small Systems

Compliance Technologies, as described

in Section VIII.A.

Proposed BAT for Radon Under Section

1415 of the SDWA

BAT for purposes of variances is the

same as BAT under Section 1412 of the

Act.

I. What Analytical Methods Are

Recommended?

EPA is proposing Liquid Scintillation

Counting (Standard Method 7500–Rn)

and de-emanation (‘‘Lucas Cell’’) as the

approved methods. The Liquid

Scintillation Counting method

designated ‘‘D 5072–92’’ by the

American Society for Testing and

Materials (ASTM) is being proposed as

an alternate method.

J. Where and How Often Must I Test My

Water for Radon?

All CWSs that use ground water must

monitor for radon. If your system relies

on ground water or uses ground water

to supplement surface water during lowflow periods, you must monitor for

radon. If you are required to monitor for

radon you must collect samples for

analysis at each entry point to the

distribution system, after treatment and

storage. Initially all CWSs using ground

water must monitor for radon at each

entry point to the distribution system

quarterly for one year. (See Section VII.E

for discussion of compliance dates). If

the results of analyses show that the

average of all first year samples at any

sample site is above the MCL/AMCL,

you must continue monitoring quarterly

at that sampling site until the average of

four consecutive quarterly samples is

below the MCL/AMCL. If the results of

analyses show that the average of all

first year samples at each sample site is

below the MCL/AMCL, you may reduce

monitoring to once a year at State

discretion at each sample site. If the

results indicate that the average of the

four quarterly samples are close to the

MCL/AMCL (as discussed next), the

State may require you to continue

monitoring quarterly.

The State may allow you to reduce

monitoring for radon to a frequency of

once every three-years, if the average

from four consecutive quarterly samples

is less than 1⁄2 the MCL/AMCL and the

State determines that your system is

reliably and consistently below the

MCL/AMCL. However, if a sample

collected while monitoring annually or

less frequently exceeds the radon MCL/

AMCL, the monitoring frequency must

be increased to quarterly until the

average of 4 consecutive quarterly

samples is less than the MCL/AMCL.

The State may require the collection of

a confirmation sample(s) to verify the

result of the initial sample. In the case

of reduced monitoring, if the analytical

results from any sampling point are

found to exceed 1⁄2 the MCL/AMCL, the

State may require you to collect a

confirmation sample at the same

sampling point. The results of the initial

sample and the confirmation sample(s)

will be averaged and the resulting

average will be used to determine

compliance. States may, at their

discretion, disregard samples that have

obvious sampling errors.

If, after initial monitoring, the State

determines that it is highly unlikely that

radon levels in your system will be

above the MCL/AMCL, the State may

grant a waiver reducing monitoring

frequency to once every nine years. In

granting the waiver, the State must take

into consideration factors such as the

geological area of the source water and

previous analytical results which

demonstrate that radon levels do not
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59253

occur above the MCL/AMCL. If you are

granted a waiver, it remains in effect for

a nine year period.

If you monitor for radon after

proposal of this rule, you may use the

data, at the State’s discretion, toward

satisfying the initial sampling

requirements for radon. Your

monitoring program and the methods

used to analyze for radon must satisfy

the regulations set out in the proposal.

K. May I Use Point-of-Use (POU)

Devices, Point-of-Entry (POE) Devices,

or Bottled Water To Comply With This

Regulation?

POE aeration or granular activated

carbon (GAC) would be allowable for

use to achieve compliance with MCLs.

While these POE technologies are not

considered BAT for large systems, they

are considered small system compliance

technologies (SSCTs), and thus may

serve as BAT under Sections 1412 and

1415 of the Act for systems serving

10,000 persons or fewer. Since POU

devices are used to treat water at a

single tap, radon will be released at

unacceptable levels from the other nontreated taps, including the shower head.

For this reason, POU devices do not

adequately address radon risks and will

not be allowed to be used for

compliance purposes. Likewise,

although bottled water reduces

ingestion risk from radon, it does not

reduce radon-related inhalation risks

from household water. For this reason,

compliance determinations based on

bottled water consumption cannot be

used.

L. May I Get More Time or Use a

Cheaper Treatment? Variances and

Exemptions

Variances and Exemptions (Section

1415.a of the SDWA)

States and Tribes with primary

enforcement responsibility (‘‘primacy’’)

may issue a variance under Section

1415(a)(1)(A) of the Act to a CWS that

cannot comply with an MCL because of

source water characteristics on

condition that the system install the best

available technology. Under Section

1416 of the Act, primacy entities may

exempt a CWS from an NPDWR due to

‘‘compelling factors’’, subject to the

restrictions described in the Act.

Primacy entities may require systems to

implement additional interim control

measures such as installation of

additional centralized treatment or POE

devices for each customer as measures

to reduce the health risk before granting

a variance or exemption. The primacy

entity must find that the variance or

exemption will not pose an

‘‘unreasonable risk to health’’, as

determined by the State or other

primacy entity. Guidance for estimating

‘‘unreasonable risk to health’’ (URTH)

values for contaminants, including

radon, is being developed by EPA and

will result in an upcoming publication

(a draft of the guidance is expected in

the Fall of 1999). Preliminary

information regarding URTH values may

be found elsewhere (Orme-Zavaleta

1992, USEPA 1998f). States must

require CWSs to provide POE devices or

other means, as appropriate to the risks

present (i.e., no POU or bottled water for

volatile contaminants, such as radon), to

reduce exposure below unreasonable

risk to health values before granting a

variance or exemption.

‘‘Small Systems Variances’’ (Section

1415(e) of the SDWA)

For NPDWRs proposed after the 1996

Amendments to the Act, EPA is

required to evaluate the affordability

and technical feasibility of treatment

technologies for use as compliance

technologies for small systems. Three

categories of small systems will be

considered: those serving: (1) 25–500,

(2) 501–3,300, and (3) 3,301–10,000

persons. If EPA determines that source

water conditions exist for one or more

small water system size categories such

that typical small systems within a

given category will not be able to afford

and/or implement a technology capable

of achieving compliance, then EPA will

designate applicable ‘‘small systems

variance technologies’’ (SSVTs) capable

of achieving contaminant levels that are

‘‘protective of public health’’. Primacy

entities may issue small systems

variances to eligible CWSs that install

and properly maintain a listed SSVT.

For a small system to be eligible for a

small systems variance, the primacy

entity must determine that the system

cannot afford to comply through

installing treatment, finding an alternate

source of water, or restructuring/

consolidating.

EPA has determined that affordable

and technically feasible technologies

exist for radon removal for all classes of

small systems. Under the 1996 SDWA,

if EPA lists at least one small systems

compliance technology for a given

system size category for all source water

qualities, then it may not list any small

systems variance technologies for that

size category, i.e., small systems

compliance technologies and variance

technologies are mutually exclusive. For

this reason, no small system will be

eligible for a small systems variance for

radon under the SDWA (Section

1415(e)). Small systems may be eligible

for general variances (under Section

1415.a of the Act) and/or exemptions on

a case by case basis. It is also important

to emphasize that the presumptive

regulatory expectation for small systems

is an MMM program (in the absence of

a State MMM program) and compliance

with the AMCL of 4000 pCi/L. Thus, for

the vast majority of small systems (those

with radon levels below 4000 pCi/L),

compliance with this proposed rule will

not involve any treatment of drinking

water.

M. What Are State Primacy, Record

Keeping, and Reporting Requirements?

The proposed Radon Rule requires

States to adopt several regulatory

requirements, including public

notification requirements, MCL/AMCL

for radon, and the requirements of

Subpart R in the proposed rule. In

addition, States and eligible Indian

tribes will be required to adopt several

special primacy requirements for the

Radon Rule. The proposed rule includes

additional reporting requirements for

MMM program plans. The proposed

rule also requires States to keep specific

records in accordance with existing

regulations. These requirements are

discussed in more detail in Section IX

of this preamble.

N. How Are Tribes Treated in This

Proposal?

The proposal provides Tribes the

option of seeking ‘‘treatment in the same

manner as a State’’ for the purposes of

assuming enforcement responsibility for

a CWS program, and developing and

implementing an MMM program (see

Section VI.C). If a Tribe chooses not to

implement an EPA-approved MMM

program, any tribal CWS may develop

an MMM plan for EPA approval, under

the same criteria described in Section

VI.A.

Statutory Requirements and Regulatory

History

II. What Does the Safe Drinking Water

Act Require the EPA To Do When

Regulating Radon in Drinking Water?

The 1996 Amendments to the Safe

Drinking Water Act (PL 104–182)

establish a new charter for public water

systems, States, Tribes, and EPA to

protect the safety of drinking water

supplies. (For an overview of the

general requirements for all drinking

water regulations, see Section XVI of

this preamble). Among other mandates,

Congress amended Section 1412 of the

SDWA to direct EPA to take the

following actions regarding radon in

drinking water.
59254 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

A. Withdraw the 1991 Proposed

Regulation for Radon

Congress specified that EPA should

withdraw the drinking water standards

proposed for radon in 1991 (see

discussion in Section III.D).

B. Arrange for a National Academy of

Sciences Risk Assessment

The amendments in Section

1412(b)(13)(B) require EPA to arrange

for the National Academy of Sciences

(NAS) to conduct an independent risk

assessment for radon in drinking water

and an assessment of the health risk

reduction benefits from various

mitigation measures to reduce radon in

indoor air.

C. Set an MCLG, MCL, and BAT for

Radon-222

Congress specified in Section 1412

(b)(13) that EPA should propose a new

MCLG and NPDWR for radon-222 by

August, 1999. EPA is also required to

finalize the regulation by August, 2000.

As a preliminary step, EPA was required

to publish a radon health risk reduction

and cost analysis (HRRCA) for possible

radon MCLs for public comment by

February, 1999. As required by SDWA,

this analysis addressed: (1) Health risk

reduction benefits that come directly

from controlling radon; (2) health risk

reduction benefits likely to come from

reductions in contaminants that occur

with radon; (3) costs; (4) incremental

costs and benefits associated with each

MCL considered; (5) effects on the

general population and on groups

within the general population likely to

be at greater risk; (6) any increased

health risk that may occur as the result

of compliance; and (7) other relevant

factors, including the quality and extent

of the information, the uncertainties in

the analysis, and factors with respect to

the degree and nature of the risk.

D. Set an Alternative MCL (AMCL) and

Develop Multimedia Mitigation (MMM)

Program Plan Criteria

The amendments in Section

1412(b)(13)(F) introduced two new

elements into the radon in drinking

water rule: (1) An Alternative Maximum

Contaminant Level (AMCL), and (2)

radon multimedia mitigation (MMM)

programs. If the MCL established for

radon in drinking water is more

stringent than necessary to reduce the

contribution to radon in indoor air from

drinking water to a concentration that is

equivalent to the national average

concentration of radon in outdoor air,

EPA is required to simultaneously

establish an AMCL. The AMCL would

be the standard that would result in a

contribution of radon from drinking

water to radon levels in indoor air

equivalent to the national average

concentration of radon in outdoor air. If

an AMCL is established, EPA is to

publish criteria for State multimedia

mitigation (MMM) programs to reduce

radon levels in indoor air. Section VI of

this preamble describes what a State or

public water system must have in their

multimedia mitigation program plan.

E. Evaluate Multimedia Mitigation

Programs Every Five Years

Once the MMM programs are

established, EPA must re-evaluate them

no less than every five years (Section

1412(b)(13)(G)). EPA may withdraw

approval of programs that are not

expected to continue to meet the

requirement of achieving equal or

greater risk reduction.

III. What Actions Has EPA Taken on

Radon in Drinking Water Prior to This

Proposal?

A. Regulatory Actions Prior to 1991

Section 1412 of the SDWA, as

amended in 1986, required the EPA to

publish Maximum Contaminant Level

Goals (MCLGs) and to promulgate

NPDWRs for contaminants that may

cause an adverse effect on human health

and that are known or anticipated to

occur in public water supplies. On

September 30, 1986, EPA published an

advance notice of proposed rulemaking

(ANPRM) (51 FR 34836) concerning

radon-222 and other radionuclides. The

ANPRM discussed EPA’s understanding

of the occurrence, health effects, and

risks from these radionuclides, as well

as the available analytical methods and

treatment technologies, and sought

additional data and public comment on

EPA’s planned regulation.

EPA’s Science Advisory Board (SAB)

reviewed the ANPRM and the four draft

criteria documents that supported it

prior to publication of the ANPRM in

the Federal Register. EPA subsequently

revised the criteria documents and

resubmitted them to the SAB for review

during the summer of 1990. EPA then

revised the criteria documents based on

this additional round of SAB review and

presented a summary of the SAB

comments and the Agency’s responses

in a 1991 Notice of Proposed

Rulemaking (NPRM).

B. The 1991 NPRM

On July 18, 1991 (56 FR 33050), EPA

proposed a NPDWR for radon and the

other radionuclides addressed in the

1986 ANPRM. The 1991 notice, which

built on and updated the information

assembled for the 1986 ANPRM,

proposed an MCLG, an MCL, BAT, and

monitoring, reporting, and public

notification requirements for radon in

public water supplies. The proposed

MCLG was zero, the proposed MCL was

300 pCi/L, and the proposed BAT was

aeration. Under the proposed rule, all

CWSs and NTNCWSs relying on ground

water would have been required to

monitor radon levels quarterly at each

point of entry to the distribution system.

Compliance monitoring requirements

were based on the arithmetic average of

four quarterly samples. The 1991

proposed rule required systems with

one or more points of entry out of

compliance to treat influent water to

reduce radon levels below the MCL or

to secure water from another source

below the MCL.

The proposed rule was accompanied

by an assessment of regulatory costs and

economic impacts, as well as an

assessment of the risk reduction

associated with implementation of the

MCL. EPA estimated the following

potential impacts from the 1991

proposed MCL:

• An estimated lifetime cancer risk of

about two cancers for every 10,000

persons exposed to radon in drinking

water.

• Avoidance of about 80 cancer cases

per year.

• About 27,000 public water systems

affected.

• A total annual cost of about $180

million.

The Agency received substantial

comments on the proposal and its

supporting analyses from States, water

utilities, and other stakeholder groups.

EPA has included in Appendix I of this

preamble a summary of major public

comments on the 1991 NPRM and how

EPA subsequently addressed those

comments.

C. 1994 Report to Congress: Multimedia

Risk and Cost Assessment of Radon

In 1992, Congress directed EPA to

report on the multimedia risks from

exposure to radon, the costs to control

this exposure, and the risks from

treating to remove radon. EPA’s 1994

Report to Congress (USEPA 1994a)

estimates the risk, fatal cancer cases,

cancer cases avoided and costs for

mitigating radon in water and in indoor

air. The Report found that cancer risks

from radon in both air and water are

high. While radon risk in air typically

far exceeds that in water, the cancer risk

from radon in water is higher than the

cancer risk estimated to result from any

other currently regulated drinking water

contaminant.

EPA conducted a quantitative

uncertainty analysis of the risks

associated with exposure to radon in
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59255

drinking water. This analysis, reviewed

by EPA’s SAB at the direction of

Congress, found that:

• People are exposed to waterborne

radon in three ways: (1) From ingesting

radon dissolved in water; (2) from

inhaling radon gas released from water

during household use; and (3) from

inhaling radon progeny derived from

radon released from water.

• The estimated total U.S. cancer

fatalities per year from unregulated

waterborne radon via all three routes of

exposure were 192, with a range from

about 51 to 620.

• The estimated annual cost was $272

million.

The 1994 Report to Congress noted

that the regulated industry estimated

considerably higher costs than EPA for

a 300 pCi/L MCL. For example, in

October 1991 the American Water

Works Association (AWWA) estimated

national costs at $2.5 billion/year (for

discussion of this issue, see Section G

of the Appendix to this preamble). The

final part of the report included the

SAB’s comments on each analysis

presented and an EPA discussion of the

issues raised by the SAB.

D. 1997 Withdrawal of the 1991 NPRM

for Radon-222

As required by the SDWA as

amended, EPA withdrew the MCLG,

MCL, and monitoring, reporting, and

public notification requirements

proposed in 1991 for radon-222 on

August 6, 1997 (62 FR 42221). No other

provision of the 1991 proposal was

affected by this withdrawal.

E. 1998 SBREFA Small Business

Advocacy Review Panel for Radon

In 1998, EPA convened a Small

Business Advocacy Review Panel to

address the radon rule, in accordance

with the Regulatory Flexibility Act

(RFA) as amended by the Small

Business Regulatory Enforcement

Fairness Act (SBREFA). The Panel of

representatives from EPA, the Office of

Management and Budget’s Office of

Information and Regulatory Affairs, and

the Small Business Administration’s

Office of Advocacy reviewed technical

background information related to this

rulemaking, and reviewed comments

provided by small business and

government entities affected by this

rule. The Panel made recommendations

in a final report to the Administrator

which included a discussion of how the

Agency could accomplish its

environmental goals while minimizing

impacts to small entities. For additional

details, see Section XIV.B of this

proposal.

F. 1999 HRRCA for Radon in Drinking

Water

EPA published the Health Risk

Reduction and Cost Analysis required

by the SDWA on February 26, 1999 (64

FR 9559), and took public comment for

45 days. EPA held a one-day public

meeting in Washington, D.C. on March

16, 1999, to present the HRRCA and the

latest MMM framework, and discuss

stakeholder questions and issues. For

details of the contents of the HRRCA

and EPA’s response to significant public

comment, see Section XIII of this

preamble.

Requirements

IV. To Which Water Systems Does This

Regulation Apply?

The SDWA directs EPA to develop

national primary drinking water

regulations (NPDWRs) that apply to

public water systems (PWSs). The

statute defines a PWS as a system that

provides water to the public for human

consumption if such system has at least

15 service connections or regularly

serves at least 25 individuals (Section

1401(4)(A)). EPA’s regulations at 40 CFR

141.2 define different types of PWSs. A

community water system (CWS) serves

at least 15 service connections used by

year round residents or regularly serves

at least 25 year-round residents. A noncommunity system does not serve yearround residents; rather, it (1) regularly

serves at least 25 of the same persons

over 6 months of the year (a ‘‘nontransient’’ system such as a restaurant or

church) or (2) does not serve at least 25

of the same persons over 6 months of

the year (a ‘‘transient’’ system such as a

campground or service station).

The regulation for radon in drinking

water and the multimedia approach for

reduction of radon in indoor air (MMM

program) proposed in this notice applies

only to CWSs that use ground water or

mixed ground and surface water (see

following discussion regarding ‘‘mixed’’

supplies). The proposed regulation does

not apply to transient water systems

because most people who use such

facilities do so only occasionally (e.g.,

travelers). There is no evidence that

such short-term exposure to radon

would cause acute illness. The data on

which health risks from radon were

determined for this rulemaking reflect

long-term exposure (see chapter 3 of the

RIA (USEPA 1999f) HRRCA section that

discusses calculation of risk). And, as

discussed next in the context of nontransient non-community systems, even

workers at transient facilities who

regularly drink the water would be

expected to have much less exposure

than persons served by community

water systems. For these reasons, the

proposed rule does not cover transient

systems.

The proposed regulation also does not

apply to non-transient non-community

(NTNC) water systems. EPA has

determined that the risks posed to

persons served by NTNC systems (such

as factories, hospitals, and schools with

their own drinking water wells) are

substantially less than the risks to

persons served by community water

systems.

The Agency recently completed a

preliminary analysis of radon

occurrence (using data provided by six

States), exposure and risk at NTNC

public water systems. Results from this

preliminary analysis indicate that even

though radon concentrations are likely

to be about 60 percent higher at NTNC

locations than at locations served by a

community water system, the lifetime

average risk to individuals who work or

attend school in buildings served by a

groundwater-based NTNC system is

probably about 17 percent of the average

risk to a worker (and 6.7 percent of the

average risk to a student) exposed in a

home served by a community ground

water system. The reason that risks are

lower in the NTNC setting than the

residential setting is that people who are

exposed at NTNC locations spend a

smaller fraction of their lifetime there

than in the home. Further, in the

particular case of students most do not

spend their entire school years in the

same school. EPA also notes that there

is limited data in this area, and more

information is needed on how water is

used in NTNC facilities and on the

contribution NTNC water use makes to

radon inhalation risk. In addition, the

overall population served by NTNC

PWSs is relatively small (5.2 million vs.

89.7 million in homes served by CWSs

using ground water (USEPA 1999b)).

EPA acknowledges that the SDWA

applies to all public water systems.

However, EPA believes that limiting the

applicability of the radon rule to

community water systems where the

risk from radon exposure is the greatest

meets a major goal of Congress in

enacting the 1996 amendments to the

Act-to focus regulations on the most

significant problems. In the Conference

Report adopting the 1996 amendments,

Congress finds that ‘‘more effective

protection of public health requires—a

Federal commitment to set priorities

that will allow scarce Federal, State, and

local resources to be targeted toward the

drinking water problems of greatest

public health concerns. ‘‘ H. Rep. 104–

182, Sec. 3. Moreover, Congress

specifically directed EPA in setting the

NPDWRs for radon to take into
59256 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

consideration the costs and benefits of

control programs for radon from other

sources. EPA has used this authority in

this proposal to set the MCL at 300 pCi/

L and to encourage small systems to

implement the MMM program and

comply with the AMCL. In both

circumstances, EPA took into account

the fact that programs to control radon

in indoor air promise greater benefits at

considerably less cost. EPA believes this

cost-effectiveness factor is also relevant

in determining the applicability of the

radon rule. EPA’s preliminary analysis

of the risk associated with exposure to

radon from NTNC systems is that it is

much less than the risk from exposure

from CWSs. For this reason, EPA has

determined that it is not cost-effective to

regulate these systems.

However, it is important to note that

this analysis is based on limited

occurrence and exposure data. In

particular, relatively little is known

about the transfer factor for release of

radon from water into indoor air at

NTNC locations, or about the

equilibrium factor affecting the amount

of radon in indoor air at such locations.

The calculations done by EPA to date

have assumed that certain values for

these parameters at NTNC locations are

similar to those in homes, although the

data are limited.

The EPA is soliciting comment on the

proposal to exclude NTNC PWSs from

the radon regulation. EPA is soliciting

comments on the Agency’s preliminary

analysis of radon exposure in NTNC

PWSs, as well as any additional data on

key parameters, including data on the

release of radon from drinking water in

the types of buildings (e.g., restaurants,

factories, churches, etc.) supplied by

NTNC PWSs, and occurrence of radon

in NTNC PWSs. If information by

commenters shows a greater

opportunity for risk reduction than

identified in its initial analysis, EPA

may make the final radon rule

applicable to NTNC PWSs without

further public comment.

With regard to systems using mixed

ground and surface water, current

regulations require that all systems that

use any amount of surface water as a

source be categorized as surface water

systems. This classification applies even

if the majority of water in a system is

from a ground water source. Data

currently in SDWIS does not identify

how many of these mixed systems exist

although this information would help

the Agency to better understand

regulatory impacts. To the extent that

systems correctly classified by SDWIS

as surface water systems also use

ground water that may exceed the MCL/

AMCL for radon, the costs and benefits

of the current proposal will be

underestimated.

EPA is investigating ways to identify

how many mixed systems exist and how

many mix their ground and surface

water at the same entry point or at

separate entry points within the same

distribution systems. For example, a

system may have several plants/entry

points that feed the same distribution

system. One of these entry points may

mix and treat surface water with ground

water prior to its entry into the

distribution system. Another entry point

might use ground water exclusively for

its source while a different entry point

would exclusively use surface water.

However, all three entry points would

supply the same system classified in

SDWIS as surface water.

One method EPA could use to address

this issue would be to analyze

Community Water System Survey

(CWSS) data then extrapolate this

information to SDWIS to obtain a

national estimate of mixed systems.

CWSS data, from approximately 1,900

systems, breaks down sources of supply

at the level of the entry point to the

distribution system and further

subdivides flow by source type. The

Agency could use the national estimate

of mixed systems to regroup surface

water systems for certain impact

analyses when regulations only impact

one type of source. The Agency requests

comment on this methodology and its

applicability for use in regulatory

impact analyses.

V. What Is the Proposed Maximum

Contaminant Level Goal for Radon?

A. Approach To Setting the Maximum

Contaminant Level Goal (MCLG)

Under Section 1412(b)(4) of the

SDWA, the EPA must establish

maximum contaminant level goals

(MCLG) at the level at which no known

or anticipated adverse effects on the

health of persons occur, and which

allow an adequate safety margin.

Section 1412(b)(13) requires the

Administrator to set an MCLG for radon

in drinking water.

B. MCLG for Radon in Drinking Water

As described in Section XII of this

preamble, radon is a documented

human carcinogen, classified by EPA as

a Group A carcinogen (i.e., there is

sufficient evidence of a causal

relationship between exposure to radon

and lung cancer in humans). Radon is

classified as a known human carcinogen

based on data from epidemiological

studies of underground miners. This

finding is supported by a consensus of

opinion among national and

international health organizations. The

carcinogenicity of radon has been well

established by the scientific community,

including the Biological Effects of

Ionizing Radiation (BEIR VI) Committee

of the National Academy of Sciences

(NAS 1999a), the National Institute of

Environmental Health Sciences, U.S.

Department of Health and Human

Services, the World Health

Organization’s International Agency for

Research on Cancer (IARC 1988), the

International Commission on

Radiological Protection (ICRP 1987),

and the National Council on Radiation

Protection and Measurement (NCRP

1984). In addition, the Centers for

Disease Control, the American Lung

Association, the American Medical

Association, the American Public

Health Association and others have

recognized radon as a significant public

health problem.

Based on the well-established human

carcinogenicity of radon, and of ionizing

radiation in general, the Agency is

proposing an MCLG of zero for radon in

drinking water. This decision is also

supported by the NAS’ current

recommendation for a linear nonthreshold relationship between

exposure to radon and cancer in

humans. In the BEIR VI report (NAS

1999a), the NAS concluded that there is

good evidence that a single alpha

particle (high-linear energy transfer

radiation) can cause major genomic

changes in a cell, including mutation

and transformation that potentially

could lead to cancer. They noted that

even if substantial repair of the genomic

damage were to occur, ‘‘the passage of

a single alpha particle has the potential

to cause irreparable damage in cells that

are not killed.’’ Given the convincing

evidence that most cancers originate

from damage to a single cell, the

committee went on to conclude that

‘‘On the basis of these [molecular and

cellular] mechanistic considerations,

and in the absence of credible evidence

to the contrary, the committee adopted

a linear non-threshold model for the

relationship between radon exposure

and lung-cancer risk. However, the BEIR

VI committee recognized that it could

not exclude the possibility of a

threshold relationship between

exposure and lung cancer risk at very

low levels of radon exposure.’’ The NAS

committee on radon in drinking water

(NAS 1999b) reiterated the finding of

the BEIR VI committee’s comprehensive

review of the issue, that a ‘‘mechanistic

interpretation is consistent with linear

non-threshold relationship between

radon exposure and cancer risk’’. The

committee noted that the ‘‘quantitative
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59257

estimation of cancer risk requires

assumptions about the probability of an

exposed cell becoming transformed and

the latent period before malignant

transformation is complete. When these

values are known for singly hit cells, the

results might lead to reconsideration of

the linear no-threshold assumption used

at present.’’ EPA recognizes that

research in this area is on-going but is

basing its regulatory decisions on the

best currently available science and

recommendations of the NAS that

support use of a linear non-threshold

relationship. For additional information

on this issue see Section XII.C.3.

‘‘Biologic Basis of Risk Estimation’’ of

this preamble.

VI. What Must a State or Community

Water System Have in Its Multimedia

Mitigation Program Plan?

Today’s proposed rule provides States

(as defined in Section 1401 of the

SDWA) with alternatives for controlling

radon exposure. States can develop a

MMM program for the reduction of the

higher risk of radon in indoor air

together with an alternative MCL

(AMCL) of 4000 pCi/L to address the

highest levels of exposure from radon in

drinking water. If a State does not

choose this option, the community

water systems (CWS) in that State must

develop and implement local MMM

program plans or comply with an MCL

of 300 pCi/L. See Section VII for

information on the regulatory

expectations for CWSs.

A. What Are the Criteria?

1. Overview

EPA has identified four criteria that

State MMM program plans are required

to meet to be approved by EPA. MMM

program plans developed by Indian

tribes will be reviewed by EPA,

according to these same criteria. CWSs

developing local MMM programs are

also subject to these criteria. These four

criteria are: public participation, setting

quantitative goals, strategies for

achieving goals, and a plan to track and

report results.

The criteria are based on a number of

factors. Foremost, the criteria reflect the

elements found in successful voluntary

action programs for radon in indoor air

that have been underway for more than

a decade. It is estimated that at the end

of the year 2000, voluntary programs to

test homes and mitigate elevated radon

levels in indoor air and to encourage the

construction of ‘‘radon-resistant’’ new

homes will have saved some 2500 lives;

and, there is much more that can be

done. In the 1999 BEIR VI report (NAS

1999a), NAS concluded that 5,000 to

7,000 cancer cases (using two different

methods) could be avoided annually if

all homes were below EPA’s voluntary

radon action level of 4 pCi/L of air.

Incorporating these program elements

into the criteria required for the MMM

programs builds on successful efforts

and can be expected to result in an even

greater number of lives saved as more

States adopt programs and existing

programs are strengthened and

expanded.

EPA has developed criteria that allow

considerable flexibility for those

developing and expanding programs.

EPA was urged by States and other

stakeholders to avoid prescribing the

specific elements of the MMM program

in a ‘‘one size fits all’’ approach. States

and CWSs adopting MMM programs

will be required to set quantitative goals

for mitigating elevated levels of radon in

indoor air of existing homes and

building radon-resistant new homes,

and to initiate strategies to promote and

increase these activities. However, there

are requirements that will be new to

many of the State indoor radon

programs. Those adopting MMM

programs will be required to involve the

public in a number of important (and

on-going) ways, and to track and report

results from the implementation of the

programs. With these additional

elements, both the affected public and

EPA will be able to assess the success

of the MMM programs. Stakeholder

input and EPA’s experience with the

national voluntary program and the

State indoor radon programs led EPA to

conclude that these criteria will provide

the basis for a program that meets the

statutory directive for equal or greater

risk reduction benefits.

The Agency also considered equityrelated issues concerning the potential

impacts of MMM program

implementation. There is no factual

basis to indicate that minority and low

income or other communities are more

or less exposed to radon in drinking

water than the general public. However,

some stakeholders expressed more

general concerns about equity in radon

risk reduction that could arise from the

MMM/AMCL framework outlined in

SDWA. One concern is the potential for

an uneven distribution of risk reduction

benefits across water systems and

society. Under the proposed framework

for the rule, customers of CWSs

complying with the AMCL could be

exposed to a higher level of radon in

drinking water than if the MCL were

implemented, though this level would

not be higher than the background

concentration of radon in ambient air.

However, these CWS customers could

also save the cost, through lower water

rates, of installing treatment technology

to comply with the MCL. Under the

proposed regulation, CWSs and their

customers have the option of complying

with either the AMCL (associated with

a State or local MMM program) or the

MCL. EPA believes it is important that

these issues and choices be considered

in an open public process as part of the

development of MMM program plans.

Therefore, EPA has incorporated

requirements into the proposed rule that

provide a framework for consideration

of equity concerns with the MMM/

AMCL. First, the proposed rule includes

requirements for public participation in

the development of MMM program

plans, as well as for notice and

opportunity for public comment. EPA

believes that the requirement for public

participation will result in State and

CWS program plans that reflect and

meet their different constituents’ needs

and concerns and that equity issues can

be most effectively dealt with at the

State and local levels with the

participation of the public. In

developing their MMM program plans,

States and CWSs are required to

document and consider all significant

issues and concerns raised by the

public. EPA expects and strongly

recommends that States and CWSs pay

particular attention to addressing any

equity concerns that may be raised

during the public participation process.

In addition, EPA believes that providing

CWS customers with information about

the health risks of radon and on the

AMCL and MMM program option will

help to promote understanding of the

health risks of radon in indoor air, as

well as in drinking water, and help the

public to make informed choices. To

this end, EPA is requiring CWSs to alert

consumers to the MMM approach in

their State in consumer confidence

reports issued between publication of

the final radon rule and the compliance

dates for implementation of MMM

programs. This will include information

about radon in indoor air and drinking

water and where consumers can get

additional information.

EPA is encouraging the States to elect

to develop and implement State-wide

MMM program plans. Since almost all

States currently have State indoor radon

programs, EPA considers the States to

be best positioned to develop strong

MMM program plans that, when

implemented, will be expected to

achieve equal or greater radon risk

reduction when compared to

compliance with the MCL. For example,

a State-wide plan can take into account

the within-State variations in indoor

radon potential, the differences in radon
59258 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

levels in drinking water, the

experienced coalitions and cooperative

partners that have been working to

promote public action on indoor radon,

the technical expertise of State drinking

water and indoor radon programs, and

many other factors. EPA expects that the

States will be best positioned to develop

MMM program plans that are robust and

credible in terms of the level of public

participation in the development and

review process, the goals that are to be

achieved from implementation of

MMM, and the program strategies to be

used.

In the development of State MMM

program plans meeting EPA’s criteria

and in the implementation of the State’s

MMM program plan, EPA expects and

strongly recommends that the State’s

programs responsible for drinking water

and for indoor radon coordinate and

collaborate on their efforts. This is

particularly important because of the

uniqueness of the MMM/AMCL

approach which addresses radon risk

reduction in drinking water and in

indoor air in a multimedia manner that

is outside the normal regulatory

structure for drinking water. Both

programs have important

responsibilities and roles in making the

AMCL and MMM program approach

successful in achieving optimal radon

risk reduction. To this end, EPA has

included as a special primacy

requirement (see Section 142.16 of the

proposed rule) that States include in

their primacy revision application for

the AMCL a description of the extent

and nature of coordination between the

State’s interagency programs (i.e.,

indoor radon and drinking water

programs) on development and

implementation of the MMM program

plan, including the level of resources

that will be made available for

implementation and coordination

between these agencies.

CWSs developing local MMM

program plans are also subject to these

criteria. CWS MMM program plans

developed in the absence of a State

program are deemed to be approved by

EPA if they meet the same criteria and

are approved by the State. States

without a MMM program, as a special

condition of primacy (see Section

142.16 of the proposed rule), will be

required to review and approve local

CWS MMM program plans and to

submit their process for approving such

plans to EPA. The Agency considered

an approach under which it would

directly review and approve CWS MMM

program plans. However, for several

reasons, EPA is proposing that States

review local MMM program plans. EPA

believes that responsibility for such

reviews is an appropriate and natural

extension of the States’ primacy

responsibilities for oversight and

enforcement of drinking water

regulations. State review and approval

of local MMM program plans will

ensure that all elements of the radon

rulemaking—both the MMM program as

well as implementation of the AMCL/

MCL—are enforced through the State,

rather than separating elements of the

rule between the Federal and State

governments. Dividing responsibility in

such a way may complicate

implementation of both elements of the

radon rule and be confusing to both

CWSs and the public. EPA also believes

that the States are best positioned to

assist CWSs, especially small systems,

in the development of local MMM

programs plans to review and approve

local plans that meet the four criteria.

States have a direct and ongoing

regulatory relationship with CWSs as a

part of their primacy authorities, as well

as a major responsibility for public

health related policy and programs in

the State. In addition, States are aware

of and sensitive to local public health

needs and concerns, as well as other

issues, that may need to be considered

in the development and implementation

of local MMM programs. For all these

reasons, EPA is proposing an approach

today that would require the States to

review and approve local MMM

program plans in accordance with the

same criteria used in EPA’s review of

State MMM program plans. However,

EPA solicits comments on other

approaches, such as EPA review and

approval of local MMM program plans

or other options intermediate between

sole State or sole Federal responsibility.

EPA anticipates, and recommends,

that States would assist CWSs in

developing their local MMM program

plans and would approve program plans

that meet the criteria and that reflect

local radon implementation issues as

discussed in Section VI.F. In non-MMM

States, EPA is also including as a special

primacy requirement that States include

in their primacy revision application for

the MCL a description of the extent and

nature of coordination between

interagency programs (i.e., indoor radon

and drinking water programs) on

development and implementation of the

State’s review and approval process for

CWS MMM program plans, including

the level of resources will be made

available for implementation and

coordination between these agencies.

2. Criteria for MMM Program Plans

The following four criteria are

required for approval of State MMM

program plans by EPA. Local MMM

program plans developed by community

water systems are deemed to be

approved by EPA if they meet these

criteria (as appropriate for the local

level) and are approved by the State.

The term ‘‘State’’, as referenced next,

includes States, Indian tribes and

community water systems. EPA is

requesting comment on each of the

criteria for approval of State, and CWS,

MMM program plans. In particular, EPA

is requesting comment on whether the

criteria need to be more or less

stringent, and the supporting rationale

for EPA’s consideration of other

potentially credible approaches.

(a) Description of Process for

Involving the Public. (1) States are

required to involve community water

system customers, and other sectors of

the public with an interest in radon,

both in drinking water and in indoor air,

in developing their MMM program plan.

The MMM program plan must include:

A description of processes the State

used to provide for public

participation in the development of

its MMM program plan, including the

components identified in the

following paragraphs b, c, and d;

A description of the nature and extent

of public participation that occurred,

including a list of groups and

organizations that participated;

A summary describing the

recommendations, issues, and

concerns arising from the public

participation process and how these

were considered in developing the

State’s MMM program plan; and,

A description of how the State made

information available to the public to

support informed public

participation, including information

on the State’s existing indoor radon

program activities and radon risk

reductions achieved, and on options

considered for the MMM program

plan along with any analyses

supporting the development of such

options.

(2) Once the draft program plan has

been developed, the State must provide

notice and opportunity for public

comment on the draft plan prior to

submitting it to EPA.

(b) Quantitative Goals. (1) States are

required to establish and include in

their plans quantitative goals, to

measure the effectiveness of their MMM

program, for the following:

(i) Existing houses with elevated

indoor radon levels that will be

mitigated by the public; and,

(ii) New houses that will be built

radon-resistant by home builders.

EPA is proposing to require

establishing quantitative goals in these
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59259

two areas because they represent the

most direct link to the risk reduction

benefits that are the ultimate objective

of the MMM programs. In addition, EPA

analyses indicate that it is very costeffective to test and mitigate existing

homes with elevated indoor radon

levels. It is also very cost-effective to

build new homes radon-resistant,

especially in higher radon potential

areas. In the existing indoor radon

program, EPA has been encouraging the

States to promote testing and mitigation

in all areas of a State. EPA has also

encouraged the States to focus on their

activities to promote radon-resistant

new construction on the highest radon

potential areas (Zone 1) where building

homes radon-resistant is most costeffective. However, it is also costeffective to build homes in medium

potential areas (Zone 2), as well as in

‘‘hot’’ spots found in most lower radon

potential areas (Zone 3).

EPA recognizes the States’ (and

CWSs’) need for flexibility in designing

MMM programs reflecting their needs

and circumstances, in particular the

extent to which opportunities are

available for risk reduction in mitigation

of existing homes with elevated indoor

radon levels or in construction of new

homes built radon-resistant. Some

States, in particular those with a

preponderance of lower radon potential

areas (and for CWSs in lower radon

potential areas), may find it preferable

to focus more heavily on testing and

mitigation of existing housing than on

radon-resistant new construction.

EPA is requesting comment on

whether there are alternative goals that

achieve radon risk reduction and the

rationale for those goals. EPA is also

soliciting comments on the goals

outlined in paragraph (b), in particular

on the appropriateness of the goals and

whether the goals need to be more or

less stringent.

(2) These goals must be defined

quantitatively either as absolute

numbers or as rates. If goals are defined

as rates, a detailed explanation of the

basis for determining the rates must be

included.

EPA is proposing to provide this

option, in part, because opportunities

available for risk reduction in mitigation

of existing homes with elevated indoor

radon levels or in construction of new

homes built radon-resistant may vary

between States and within States. In

addition, the level of new home

construction may vary from year to year

in different parts of a State or in a local

jurisdiction. In this situation, it may be

more appropriate to set goals for radonresistant new construction as a rate,

rather than absolute numbers, to

account for this variability. This may be

especially true for CWS developing

local MMM program plans where no

new home construction is currently

taking place but may in the future.

(3) States are required to establish

goals for promoting public awareness of

radon health risks, for testing of existing

homes by the public, for testing and

mitigation of existing schools, and for

construction of new public schools to be

radon-resistant, or to include an

explanation of why goals were not

established in these program areas.

EPA is proposing that States have this

option of defining goals as absolute

numbers or as rates because, while

awareness of radon health risks is a

necessary element and a first step in

getting the public to take action on

indoor radon, public awareness, in and

of itself, does not constitute radon

exposure reduction. It does, however,

help to facilitate informed choice by the

public regarding radon testing and

mitigation. Since the level of awareness

on the health effects of radon is already

high in many States, EPA is proposing

to give flexibility to the States on this

goal. In the case of radon in schools,

many States have undertaken a range of

activities to address radon in schools

and some have done extensive testing,

in some cases passing State legislation

requiring the State to test public

schools. Therefore, EPA is proposing to

give States the option of setting these

goals for schools. Although this

approach provides flexibility in goal

setting, EPA strongly encourages those

States which do not have high levels of

public awareness on radon and where

there has been limited testing of public

schools across the State to set goals in

these areas. EPA is soliciting comment

on whether States should be required to

set quantitative goals in all or some of

these areas in paragraph (b)(3).

(c) Implementation Plans. (1) States

are required to include in their MMM

program plan implementation plans

outlining the strategic approaches and

specific activities the State will

undertake to achieve the quantitative

goals identified in paragraphs (b)(1) and

(b)(2). This must include

implementation plans in the following

two key areas:

(i) Promoting increased testing and

mitigation of existing housing by the

public through public outreach and

education and during residential real

estate transactions.

(ii) Promoting increased use of radonresistant techniques in the construction

of new homes.

(2) If a State has included goals for

promoting public awareness of radon

health risks; promoting testing of

existing homes by the public; promoting

testing and mitigation of existing

schools; and promoting construction of

new public schools to be radon

resistant, then the State is required to

submit a description of the strategic

approach that will be used to achieve

the goals.

(3) States are required to provide the

overall rationale and support for why

their proposed quantitative goals

identified in paragraphs (b)(1) and

(b)(2), in conjunction with their program

implementation plans, will satisfy the

statutory requirement that an MMM

program be expected to achieve equal or

greater risk reduction benefits to what

would have been expected if all public

water systems in the State complied

with the MCL.

(d) Plans for Measuring and Reporting

Results. (1) States are required to

include in the MMM plan submitted to

EPA a description of the approach that

will be used to assess the results from

implementation of the State MMM

program, and to assess progress towards

the quantitative goals in paragraphs

(b)(1) and (b)(2). This specifically

includes a description of the

methodologies the State will use to

determine or track the number of

existing homes with elevated levels of

radon in indoor air that are mitigated

and the number or the rate of new

homes built radon-resistant. This must

also include a description of the

approaches, methods, or processes the

State will use to make the results of

these assessment available to the public.

(2) If a State includes goals in

paragraph (b)(3) for promoting public

awareness of radon health risks; testing

of existing homes by the public; testing

and mitigation of existing schools; and,

construction of new public schools to be

radon-resistant; the State is required to

submit a description of how the State

will determine or track progress in

achieving each of these goals. This must

also include a description of the

approaches, methods, or processes the

State will use to make these results

available to the public.

B. Why Will MMM Programs Get Risk

Reduction Equal or Greater Than

Compliance With the MCL?

The National Indoor Radon Program

implemented by EPA, States and others,

has achieved substantial risk reduction

through voluntary public action since

the release of the original ‘‘A Citizen’s

Guide to Radon’’ in 1986 (USEPA 1986)

(updated: USEPA 1992b) and the U.S.

Surgeon General’s recommendation in

1988 (US EPA, 1988b) that all homes be

tested and elevated radon levels be

reduced. The program has been
59260 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

successful in achieving voluntary risk

reduction on indoor radon through a

variety of program strategies. It is

important to keep in perspective the

comparatively large potential for risk

reduction that can be achieved if all

existing homes with indoor radon levels

at or above EPA’s voluntary action level

for indoor radon of 4 pCi/L in the U.S.

were mitigated (approximately 6 million

homes). In addition there is the

potential for significant risk reduction

potential if the approximately 1 million

new homes built annually in the U.S.

were built radon-resistant. Based on the

estimated number of existing homes

fixed and the number of new homes

built radon-resistant since the national

program began in 1986, EPA estimates

that a total of more than 2,500 lives will

be saved through voluntary indoor

radon risk reduction efforts expected to

take place up through the year 2000.

Every year the rate of lives saved

increases as more existing houses with

elevated radon levels are fixed and as

more new houses are built radonresistant. On average this rate of lives

that will be saved from these risk

reduction actions increases by about 30

additional lives per year. EPA estimates

that for the year 2000, the rate of radonrelated lung cancer deaths that will be

avoided from mitigation of existing

homes and from homes built radonresistant in high radon areas will be

about 350 lives saved per year (USEPA

1999i).

Under the radon provision of SDWA,

if all States adopted the AMCL, all State

MMM programs together must be

expected to result in at minimum about

62 cancer deaths averted annually;

equal to what would be achieved with

universal compliance with the MCL.

Unlike these health risk reduction

benefits which remain constant from

one year to the next, the rate of health

benefits from reducing radon in indoor

air, as noted previously, steadily

increases every year with every

additional existing home that is

mitigated and with every new home

built radon-resistant. This steady

incremental risk reduction offered by

mitigation of existing homes with

elevated indoor radon and building

homes radon-resistant, especially during

real estate transactions and through

builder and consumer education and

State and local adoption of radonresistant building codes, holds the

potential for substantial long-term risk

reduction. NAS in their 1999 BEIR VI

Report, concluded that up to one third

(i.e., 5,000 to 7,000) of their estimated

15,000 to 22,000 annual radon-related

lung cancer deaths in the U.S. could be

avoided if all homes were below EPA’s

voluntary radon action level of 4 pCi/L

of air (NAS 1999a). This does not

include the risk reduction that is

achieved from new homes built radonresistant. The one million new homes

on average being built every year

represent a significant radon risk

reduction opportunity. Therefore, a

critical element for MMM is to utilize

and build on the indoor radon program

framework to achieve ‘‘equal or greater’’

risk reduction rather than focusing

efforts on precisely quantifying the

much more limited risk reduction that

will not occur in community water

systems complying with the AMCL (i.e.,

the difference in the risk reduction

between the MCL and the AMCL).

C. Implementation of an MMM Program

in Non-Primacy States

A State that does not have primary

enforcement responsibility for the

Public Water System Program under

Section 1413 of the SDWA (‘‘primacy’’)

and where EPA administers the CWS

program may still develop a State-wide

MMM program plan. EPA would not

expect to develop an MMM program

plan where the State elects not to

develop a State-wide MMM program

plan. Accordingly, CWSs in such

jurisdictions would be required to

comply with the more stringent MCL or

develop local MMM program plans for

approval by EPA.

The SDWA authorizes all States to

develop and submit a MMM program

plan to mitigate radon levels in indoor

air for approval by the Administrator

under Section 1412(b)(13)(G). EPA is

proposing that States that do not have

primacy may submit a plan to EPA that

meets the criteria of 40 CFR 141.302. If

the State’s plan is approved, the State

would be subject to all reporting and

compliance requirements of 40 CFR

141.303. Community water systems in

States with approved MMM programs

would comply with the AMCL of 4000

pCi/L, and would be subject to the

requirements for monitoring and

analytical methods in 40 CFR 141.20.

EPA would continue to administer

compliance with the MCL/AMCL, and

with monitoring and methods

requirements.

D. Implementation of the MMM Program

in Indian Country

Under this proposal, States can

develop State-wide MMM programs for

the reduction of radon in indoor air, and

community water systems in such States

can then comply with an AMCL of 4000

pCi/L (rather than an MCL of 300 pCi/

L). Under Section 1451 of the SDWA,

the Administrator of EPA is authorized

to treat Indian Tribes in the same

manner as States. The proposal provides

tribes the option of seeking ‘‘treatment

in the same manner as a State’’ for the

purposes of assuming enforcement

responsibility for a community water

system program, and developing and

implementing an MMM program. If a

tribe does not choose to implement an

MMM program, any tribal CWS may

develop an MMM program plan for EPA

approval, under the same criteria

described previously.

EPA is proposing to amend the

‘‘treatment as a State’’ regulations to

allow tribes to be treated in the same

manner as States for purposes of

carrying out the MMM program. Under

this proposal, a tribe would not need to

demonstrate that it qualified for

treatment in the same manner as a State

for any other purpose other than the

MMM provisions. Tribes may want to

seek treatment in the same manner as a

State for this limited purpose to the

extent that radon is a significant

problem on tribal lands because the

MMM program provides an opportunity

to focus resources on reducing the

higher risk exposure—indoor air—and

addressing radon in drinking water at

the highest levels of exposure. EPA is

proposing to amend the treatment in the

same manner as State regulations (40

CFR 142.72 and 40 CFR 142.78) to

obtain treatment as a State status solely

for the purpose of implementing the

MMM authorities. Tribes can, of course,

always apply to be treated in the same

manner as a State for primacy over the

Public Water Supply Program under 40

CFR 142.72.

A tribe applying for authority to

develop and implement an MMM

program plan that has met the criteria

under 40 CFR 142. 72 to be treated in

the same manner as a State for any

purpose will not need to reestablish that

it meets the first two criteria (40 CFR

142.72 (a) and (b)) and needs to provide

only information in 40 CFR 142.76 that

is necessary to demonstrate that the

criteria in 40 CFR 142.72 (c) and (d) are

met for the MMM program plan. A tribe

whose application for authority to carry

out the MMM program is approved must

develop and implement a MMM

program plan in accordance with 40

CFR 141.302 and 141.303.

E. CWS Role in State MMM Programs

EPA anticipates that CWSs, especially

small systems, would have a limited

role in State-wide MMM programs. For

example, States may develop

information brochures on radon that

could be distributed locally by CWSs.

EPA expects that States will want to

consult with CWSs, small and large, in
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59261

making a determination about the

nature and scope of the role, if any, of

CWSs in implementing a State-wide

MMM program. During EPA’s

stakeholder process, many States and

CWSs agreed that States were best

positioned to design and implement

effective State-wide MMM programs

and that it was not apparent what role

CWSs might take in such a program.

However, CWSs do have important

responsibilities for communicating

information on radon to their customers

(see Section VI.G).

F. Local CWS MMM Programs in NonMMM States and State Role in Approval

of CWS MMM Program Plans

The regulatory expectation of small

community public water systems

(CWSs) is that they meet the AMCL and

be associated with a MMM programeither developed by the State and

approved by EPA or developed by the

CWS and approved by the State. EPA

strongly recommends that States choose

to develop and implement State-wide

MMM programs as the most costeffective approach to manage the health

risks from radon. In those cases where

States do not elect to do a State-wide

MMM program, CWSs would need to

notify the State of its intention to

develop and submit a local MMM

program plan to the State (4 years after

publication of the final rule in the

Federal Register). EPA believes that, in

all cases, the regulatory burden of

complying with AMCL and

implementing a MMM program will be

considerably less than complying with

the more stringent regulatory level for

radon in drinking water. EPA believes

that the MMM/AMCL is the appropriate

standard for CWSs, especially for small

systems, because it results in greater

radon risk reduction and makes better

use of limited resources. EPA believes

that the four criteria for plan approval

can be applied to CWS local MMM

program plans (as appropriate for the

local level), commensurate with the

unique attributes of these CWSs and

their service areas. As previously

discussed in more detail, these four

criteria are: public participation, setting

quantitative goals, strategies for

achieving goals, and a plan to track and

report results.

In general, EPA expects that CWSs

would be able to meet the four criteria

by carrying out a wide range of diverse

activities, many of which are well

within the expertise of CWSs. However,

small CWSs would not necessarily be

expected to perform some of the

activities entirely on their own. In

carrying out certain activities, small

CWSs would be expected to seek help

from others in order to build upon and

take advantage of existing CWS and

State networks. The existing State

indoor radon programs, for example,

operate in large measure through a

network of State and local partners such

as the American Lung Association, the

National Association of Counties, the

National Environmental Health

Association, the National Safety

Council, consumer advocacy groups,

non-government organizations, and

other local and county governmental

organizations. CWSs should be able to

use the same networks and their

capabilities, and State radon in indoor

air programs should help facilitate these

contacts. The following provides some

additional perspective on the four

criteria relative to CWS MMM programs.

Public Participation: Thorough public

participation is certainly within the

capability of CWSs. Systems are often

required in the course of CWS activities,

such as operation, maintenance, water

bill collection, violation notification,

and planning for new facilities, to

involve, communicate with, inform, and

in other ways interact with the public.

Thus, these systems already engage, to

a significant degree, in public outreach

and communication. EPA expects that

such expertise can readily be directed

toward the particular public

participation requirements associated

with MMM programs. Public

participating during development of

local MMM plans will help ensure

greater local support for and

implementation of the CWS MMM

programs.

Quantitative Goals: EPA notes that the

quantitative goals that CWSs, especially

small CWSs, typically will need to

establish may be rather modest

compared to those that would be

expected for State-wide programs. The

level of risk reduction needed to ensure

‘‘equal or greater’’ risk reduction be

achieved (as if the MCL were being met)

from a local MMM program plan is a

function of and takes into account

factors such as the size of the

population served, level of radon in

drinking water, and most importantly,

the needs and goals of the community.

Strategies for Achieving Goals: EPA

recognizes that promoting public action

in the areas of new homes built radonresistant and mitigation of existing

homes with elevated levels of radon in

indoor air will be entirely new ventures

for CWSs. However, EPA believes

CWSs, including small CWSs, will be

capable of conducting various activities

designed to promote testing and

mitigation of existing homes with

elevated levels of radon in indoor air

and building of new homes to be radonresistant. Such activities include public

education programs, provision of radon

test kits, establishing networks with

local health and government officials to

gain their support and involvement in

MMM implementation, meeting with

community leaders, customers, local

real estate and home building officials

and organization, utilizing existing

information distribution network

employed by CWSs, and other types of

activities to promote public action on

indoor radon. EPA expects that MMM

program strategies for CWSs will be less

comprehensive and far reaching than

those of State MMM programs, and will

need to reflect the local character of the

community served by the CWS.

Tracking and Reporting of Results:

EPA recognizes that assessing or

tracking progress towards meeting these

goals also represents a new

responsibility for CWSs. However,

CWSs may be able to build upon their

experience and networks for

communicating with customers and

identifying their needs or concerns and

find ways to collect information about

actions taking place in the community.

To track homes built or modified to be

radon resistant, CWSs may be able to

obtain needed information from various

local and State programs and offices and

other organizations in its network. CWS

may also choose to employ contractor

support or consultant services to obtain

this information or to help track other

MMM related activities. EPA also

expects the States to provide assistance

to CWSs in developing their tracking

and assessment approach based on State

experience in determining the results of

their State indoor radon programs. EPA

recognizes that CWSs’ options for

tracking results may be more limited

than those available to the States, and

that States should consider such

limitations in their five-year review of

local programs.

CWSs may find it useful to combine

efforts with adjacent CWSs for purpose

of developing and implementing joint

MMM programs, thereby broadening

their combined expertise, local

infrastructure and institutional bases,

and network of partners. EPA also

expects that privately-owned, as well as

publicly owned, CWSs can avail

themselves of these same kinds of

networks, partnership, and consultant

services. Private systems will generally

also be well connected to the municipal

entities in the jurisdictions in which

they operate.

The report of the Small Business

Advocacy Review Panel included a

discussion of the concept of a ‘‘model

MMM program’’ for small systems

which would not be required but could
59262 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

provide a workable option for small

systems. It might address potential

concerns of the smallest systems that

anticipate they may lack the resources

and expertise to develop an MMM

program. As discussed subsequently in

Section VI. H., EPA has concerns in

general about the appropriateness and

applicability of a ‘‘one-size-fits-all’’

approach for MMM programs. A model

approach, even for small CWSs, would

not address the unique, site-specific

needs of different CWSs and their

associated communities. EPA is

requesting public comment on the

concept of a model MMM program for

CWSs.

As noted previously, EPA is strongly

recommending that States choose to

develop and implement State-wide

MMM programs as the most costeffective approach to manage the health

risks from radon which would preclude

the need for water systems to develop

such programs on their own. EPA also

believes the States which choose not to

do an MMM program have an important

role, and are the best positioned, to

assist CWSs in development of local

MMM program plans. EPA will also be

providing guidance to assist CWSs,

including small CWSs, in the

development of local MMM programs.

This section has discussed the manner

in which the four criteria could be

applied to CWSs in non-MMM States.

EPA is requesting comment on

approaches to applying these criteria to

CWSs, especially the smallest CWSs, in

view of the capabilities of these systems

and their ability to get assistance from

others. EPA is also requesting comment

on options that may be available to

CWSs, particularly, small systems, to

develop and implement an MMM

program plan.

In summary, EPA recognizes that

CWSs do not have the same institutional

base and infrastructure, legislative

authority, proportionate resource base,

or indoor radon program experience as

States on which to base development of

a local MMM program plan. However,

EPA believes that the four criteria for

approval are equally applicable to both

States and CWSs, and can be applied to

CWSs (particularly small CWSs) in a

manner that recognizes and accounts for

these differences. As discussed

previously, the manner in which these

criteria are addressed by CWSs in local

MMM program plans, and the level and

scope of effort, will necessarily differ

from that embodied in State plans.

States should consider these differences

in evaluating CWS MMM program plans

and in their five-year review of CWS

MMM program implementation. EPA

believes that States, in particular, are

best positioned to assist CWSs,

especially small systems, in the

development of local MMM programs

that satisfy the four criteria, and expects

them to provide such assistance. In

evaluating CWS plans, States should

exercise flexibility in their review and

approval process, especially for small

CWSs, recognizing that they will not

have the same institutional and resource

base or experience and may need to

obtain assistance from others.

The Agency expects that most systems

in non-MMM States with radon levels

between 4,000 pCi/L and 300 pCi/L will

develop and submit MMM program

plans. However, the Agency recognizes

that some CWSs in non-MMM States

may elect not to develop a MMM

program plan for a variety of reasons. In

these cases, certain options are available

to small CWSs. They may consider

working with one or more other systems

for the purposes of developing and

implementing an MMM program plan,

in order to take advantage of greater

institutional capabilities. If a system

does not develop an MMM program

plan on its own or together with other

systems, the system must comply with

the MCL of 300 pCi/L through any

available means (e.g., blending, use of

alternate sources, and treatment).

From a risk communication

standpoint, EPA wishes to convey to

customers of small CWSs that its

regulatory expectation for these systems

is that they meet the AMCL and

implement an MMM program. However,

CWSs can choose to meet the MCL

rather than take the MMM approach. If

a CWS opts for the MMM/AMCL

approach but is unable to develop and

successfully implement a Stateapproved MMM program plan, it may be

required as part of an enforcement

order, to meet the MCL rather than

comply with the MMM/AMCL. The

Agency requests comment on this

approach for small system MMM

programs.

The SDWA provides that EPA will

approve local water system MMM

program plans and EPA has developed

the criteria to be used for approving

MMM program plans, as discussed in

(A). EPA will review and approve State

MMM program plans. CWS MMM

program plans that address the criteria

and are approved by the State are

deemed approved by EPA. The

proposed rule requires States that do not

have a State-wide MMM program, as a

condition of primacy for the radon

regulation, to review MMM program

plans submitted by CWSs and to

approve plans meeting the four criteria

for MMM program plans discussed in

Section VI.A. of this, including

providing notice and opportunity for

public comment on CWS MMM

program plans. EPA solicits comment

on this approach to reviewing and

approving local MMM plans. Under

SDWA, MMM program plans submitted

by CWSs are to be subject to the same

criteria and conditions as State MMM

program plans. EPA believes that the

States are best positioned to assist

CWSs, especially small systems, in the

development and review of local MMM

program plans that meet the four

criteria, and to have public health

oversight of the progress of the

implementation of these local radon risk

reduction programs. EPA encourages

those States not choosing to develop a

State-wide MMM program plan to

exercise flexibility in their review and

approval of local MMM program plans,

especially for small CWSs, recognizing

that CWSs will not have the same

institutional base, nor the State’s

program experience on indoor radon, on

which to base to local development of

a MMM program plan. EPA expects that

the State drinking water programs and

indoor radon programs will work

collaboratively in assisting CWSs that

elect to develop and implement local

CWS MMM program plans and comply

with the AMCL. In non-primacy states,

EPA will review and approve local CWS

MMM program plans and oversee

compliance with the AMCL if the state

chooses not to do a state-wide MMM

program plan. MMM program plans

developed by Indian Tribes or tribal

community water systems will be

reviewed by EPA. The specific

requirements of a CWS in a State with

a State-wide MMM program are

addressed in Section VI.E. CWSs may

choose to meet the MCL.

For those CWSs (both large and small)

in non-MMM States that develop local

MMM program plans, the State would

review the MMM program at least once

every 5 years and provide progress

reports to the EPA in keeping with the

statutory requirements of the SDWA and

this Section. (States may also establish

interim reporting requirements for the

CWS under a MMM program to help

ensure adequate progress toward the

goals set forth in the local MMM

program plan.) Failure of a CWS to

develop its MMM program plan by the

required regulatory deadline or failure

of a CWS to implement its approved

MMM program plan (5 years and 51⁄2

years, respectively after the final rule is

published) would be a violation of this

regulation unless the CWS is complying

with the MCL. It is expected that a CWS

would be given time to correct any

violations relating to its MMM program
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59263

through an appropriate enforcement

action.

G. CWS Role in Communicating to

Customers

At a minimum, CWSs have important

responsibilities for communicating

information on radon to their customers.

Under the requirements of the

Consumer Confidence Rule (CCR),

CWSs will be required to provide key

information on the health effects of

radon should the level of radon in

drinking water exceed the MCL (or

AMCL in States with MMM programs).

Today’s action also updates the

standard CCR rule requirements and

adds special requirements that reflect

the multimedia approach of this rule.

The intent of these provisions is to

assist in clearer communication of the

relative risks of radon in indoor air from

soil and from drinking water, and to

encourage public participation in the

development of the State or CWS MMM

program plans. Today’s action also

proposes to require CWSs to add

information to the mandatory yearly

report which would inform their

customers on how to get involved in

developing their State or local CWS

MMM program plan. This information

would include a brief educational

statement on radon risks, explaining

that the principal radon risk comes from

radon in indoor air, rather than drinking

water, and for that reason, radon risk

reduction efforts may be focused on

indoor air rather than drinking water.

This information will also note that

many States and systems are in the

process of creating programs to reduce

exposure to radon, and encourage

readers to call for more information.

This information would be provided

every year until the compliance date for

implementation of State MMM

programs (or CWS local MMM programs

in States without a State-wide MMM

program. (See Section X of this

preamble for more information on CCR

and public notice requirements for

radon). EPA is also planning to develop

public information materials on radon

in drinking water and indoor air as

‘‘tools’’ to assist CWSs, as well as the

States, Indian tribes, and others, with

the risk communication issues

associated with the MCL, AMCL, and

MMM.

H. How Did EPA Develop These

Criteria?

EPA obtained extensive stakeholder

input in developing the regulatory

criteria for State MMM program plans.

Stakeholders participating in this

process represented many diverse

groups and organizations with an

interest in radon, both from the

perspective of radon in drinking water

and of radon in indoor air. This

included State drinking water and State

radon program representatives,

municipal and privately owned public

water system suppliers, local

government officials, environmental

groups, and organizations representing

State health officials, county

governments, public interest groups,

and others.

As part of the process of getting

stakeholder input on development of

MMM guidelines and criteria, EPA

presented several conceptual framework

options for MMM for discussion and

consideration. Three preliminary

approaches were discussed: (1) To set

specific numerical targets in mitigations

of existing houses and houses built

radon-resistant (as surrogates for lives

saved) for each State to meet; (2) to set

a level of effort that States must

demonstrate would be achieved under

their MMM plan; and (3) to set

minimum core indoor radon program

elements required for all plans.

Under the first approach, specific

targets to achieve ‘‘equal’’ risk reduction

could be set using a variety of

approaches and tools and based on a

number of factors, such as the level of

radon in the drinking water, the number

of people served by that system, and

other factors. It would also require

allocating among the States the total

number of lives saved nationally by

universal compliance with the MCL

(estimated to be about 62 lives saved

yearly). The allocation of lives saved by

States would likely lead to some State

targets being fractions of a life saved

yearly, depending on the number of

systems, radon levels, and people

served. Many stakeholders thought that

significant attention would need to be

paid to the risk communication

challenges of communicating this

approach to the public. Although some

stakeholders thought this approach

might be workable, others did not

consider it universally applicable or

workable and that it might preclude

flexibility and innovation.

The second approach, ‘‘level of

effort’’, would focus more on a plan for

implementation of risk reduction

strategies using a point system where

different risk reduction strategies (such

as public education, radon-resistant new

construction code adoption, etc.) would

be assigned a specific number of points

based on potential to achieve health risk

reduction. The number of State-specific

points that a MMM program plan would

have to meet to be approved would

require determining the number of

systems complying with the AMCL

rather than the MCL, the radon levels in

their drinking water, and population

served. This approach would give States

flexibility in choosing the combination

of indoor radon risk reduction strategies

that best meets the needs of that State

by giving them a menu of approaches

from different categories of strategies

with different assigned points. There are

two difficulties in implementing this

approach that would need to be

addressed. First, it may be difficult to

assign in advance a specific quantified

value for different strategies in terms of

a numerical outcome in risk reduction

(i.e., in lives saved or in existing homes

mitigated or houses built radonresistant). EPA requested the National

Academy of Sciences (NAS), as part of

its assessment of radon in drinking

water, to ‘‘prepare an assessment of the

health risk reduction benefits associated

with various mitigation measures

[described in SDWA] to reduce radon

levels in indoor air.’’ Although the NAS

included some review of the States’

experience with public education and

risk communication, they did not

include a quantitative assessment of the

‘‘health risk reduction benefits’’

associated with specific ‘‘mitigation

measures’’ referred to by SDWA.

Second, risk communication research

has shown, and many stakeholders

agreed, that a variety of strategies must

be employed simultaneously when

trying to get voluntary public actions on

preventive health and safety measures.

It is often difficult to single out or

characterize, for example, the number of

people who take voluntary health risk

reduction actions because of viewing a

particular televised public service

announcement separate from other

messages, activities, communications,

and efforts being implemented by

society to reduce that particular public

health risk.

Setting specific State risk reduction

targets or a level of effort point system

were considered in part to address

language in the SDWA radon provision

that State plans approved by EPA are

expected to achieve health risk

reduction benefits ‘‘equal to or greater

than the health risk reduction benefits

that would be achieved if each public

water system in the State complied with

the maximum contaminant level

[MCL]* * *.’’ As some stakeholders

noted, there are complexities associated

with determining risk reduction targets

(e.g., in pCi/L) for indoor radon needed

to substitute or ‘‘make-up’’ for some

very small level of risk reduction that

would not occur if systems comply with

the AMCL. Careful attention would

need to be paid to ensuring that this
59264 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

approach did not produce the

unintended effect of narrowly focusing

or limiting the risk reduction goals of

MMM program plans. Some States and

other stakeholders were concerned that

a complex approach, that may be

difficult to communicate to the public,

could hamper voluntary public action

currently taking place on indoor radon.

Some States thought that they may have

the data and/or tools that would permit

such an approach.

The third conceptual approach was to

require MMM program plans to include

a set of core program elements, without

targets or points, to be determined by

EPA. This would require a set of basic

program elements that each State MMM

program plan would have to incorporate

to be approved by EPA. In addition, the

States could choose to add additional

program elements from a menu of

strategies to be provided by EPA. An

example of implementation of a core

program element might be that each

State would have to adopt radonresistant new construction standards

into their State and local building codes,

or require testing and mitigation firms to

register with the State and report

numbers of radon tests and mitigations

conducted. Many stakeholders were

concerned that this approach might not

provide sufficient flexibility needed by

the States to reflect their particular

needs, including the scope of the radon

in drinking water and indoor radon

problem, and the varying extent to

which the States have been addressing

their indoor radon problem through

their existing State radon programs.

EPA is soliciting public comment on

these three alternative conceptual

frameworks for MMM program plans

that were examined through the

stakeholder process and is also

requesting public comment on other

potential frameworks and rationale for

why and how these would achieve

increased radon risk reduction.

While stakeholders had differing

views of the three conceptual

approaches presented by EPA for

discussion purposes, a number of

mutual concerns and issues integral to

formulation of a conceptual framework

for MMM were identified. The following

set of broad issues and concerns raised

by stakeholders were considered in the

development of the required criteria that

EPA is proposing.

A uniform approach, that is, a ‘‘one

size fits all’’ approach to MMM might

not provide States with the flexibility

they need to custom tailor their plans to

their needs. Every State is different in

terms of the extent and magnitude of the

indoor radon problem, the nature of the

existing State indoor radon program, the

levels of radon in public water supplies,

and many other factors.

Because the SDWA framework for

radon permits States to choose to adopt

either the MCL or AMCL/MMM option,

some stakeholders believed that States

might be less inclined to adopt the

MMM/AMCL approach if it were

considered too complex and difficult to

implement and communicate to the

public. The approach needs to be simple

and straightforward, provide flexibility

to accommodate the variety of needs in

different States, and encourage

innovation at the State and local level.

MMM will be most effective if it is

built on and consistent with the

foundation and infrastructure of the

existing State indoor radon programs.

States are better positioned than public

water suppliers to achieve radon risk

reduction under MMM programs. Most

States currently have a voluntary radon

program. Some States noted the need for

some consistency between the criteria

and objectives for MMM program plans

and the goals, priorities, and EPA’s

existing State Indoor Radon Grant

(SIRG) program guidance.

States and other stakeholders raised

concerns about the potential

relationship between MMM and the

current State indoor radon programs.

Stakeholders strongly encouraged EPA

to carefully identify and consider the

potential for negative impacts of MMM

requirements on current State efforts on

indoor radon. In particular there were

concerns that attention and resources

might be diverted to the MMM program.

States might choose not to do a MMM

program if the effectiveness or

infrastructure of their current indoor

radon program might be reduced, or if

it does not help States meet the goals of

their voluntary programs. This would be

counter-productive if it resulted in

reduced efforts and diminished

infrastructure of a State’s voluntary

program already achieving indoor radon

risk reduction.

Some States felt it was important to

have extensive public debate and

examination of any program proposed

by the State in order to get public

support for the AMCL and MMM

approach.

A number of stakeholders noted the

need for MMM programs to have

definable endpoints or goals, show how

these endpoints will be attained, and

describe how results will be

determined. Some States indicated the

importance of demonstrating to the

public that the program is achieves

radon risk reduction.

Stakeholders noted that the level of

risk reduction that can be achieved by

focusing resources and effort on radon

in indoor air is significantly greater than

what can be achieved by universal

compliance with the MCL. MCL-based

risk reduction targets would also be

significantly smaller than the risk

reduction already being achieved.

Therefore it is important to focus on the

greater risk reduction potential for

radon in indoor air, and on

enhancement of indoor radon programs,

rather than focus on the smaller risk

reduction potential from radon in water.

In developing and deciding on

proposed criteria, EPA took into account

these stakeholder views and concerns,

as well as EPA’s goals for MMM and the

current approach used by EPA and the

States to get indoor radon risk

reduction. This information and

experience taken together led to the

proposed MMM criteria that are based

upon three elements: (1) Involve the

public in development of MMM; (2)

track the level of indoor radon risk

reduction that occurs; and, (3) build on

the existing framework of State indoor

radon programs.

First, stakeholders suggested that

extensive public participation in the

development of a State MMM program

plan is important. One important

approach is to involve various segments

of the public, from community water

system customers to key public health

and other organizations, the business

community, local officials, and many

others. The public needs to be informed

about and participate in the MMM

development process to ensure that the

goals and other elements of the plan

will be publicly supported, responsive

to the needs of the various stakeholders,

and meet public and State goals for

reducing indoor radon. Such a process

may also result in increased public

awareness and voluntary action to

reduce the levels of indoor radon.

Stakeholder involvement can help

States clearly define goals and design

the process and strategies for meeting

these goals. EPA recognizes that there

are a variety of non-quantitative and

quantitative approaches, tools, and

types of information that can be used to

develop goals, but public input is very

important to this process. The public

involvement in development and

examination of plans will help to get

support and buy-in from all

stakeholders to a set of goals, program

strategies, and results measurement, and

thus, helps to ensure program success.

Second, a successful MMM program

plan needs to include a provision for

determining progress on reducing the

public’s exposure to indoor radon, and

for reporting back to the public. In the

case of indoor radon, risk reduction

results can be evaluated by tracking or
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59265

in some way determining the level of

existing home mitigation and new

homes built radon-resistant. A few

States already track this information

closely. Many do not. EPA believes that

there are a variety of approaches

currently being used, such as

statistically-based surveys; State

requirements for tracking testing and

mitigation by radon testing and

mitigation companies; voluntary

agreement by builders to provide

information on construction of radonresistant homes; and other approaches.

EPA also recognizes the importance of

providing States the flexibility to craft

new and innovative approaches for

tracking and assessing progress.

Through implementation of a State-wide

MMM/AMCL approach, States may be

able to provide new incentives and

opportunities for gathering the

information the State will need to

demonstrate to the public, and EPA, that

progress is being made in getting public

action to reduce radon risks.

Third, building MMM on the

framework of existing State indoor

radon programs takes advantage of the

existing programs already working to get

public action on indoor radon. Nearly

every State currently has a program with

existing policies, public outreach and

education programs, partner networks

and coalitions, and other infrastructure.

States have used the State Indoor Radon

Grant (SIRG) funds available under Title

III of the Toxics Substances Control Act

(TSCA) to develop a variety of radon

strategies, including distributing

information materials to educate the

public, maintaining radon hotlines,

conducting training programs, providing

technical assistance, operating

certification programs for the radon

industry, setting up regulatory

requirements for industry reporting of

testing and mitigation, conducting

surveys (testing) of homes and schools,

working with local governments in

high-risk areas to establish incentive

programs for radon-resistant new

construction, and many other activities.

Many of these activities are consistent

with the findings of the National

Academy of Sciences. They found three

factors were most important for

motivating the public to test and fix

their home: (1) A radon awareness

campaign; (2) promoting the widespread

voluntary testing by the public of indoor

radon levels; and (3) educating the

public about mitigation and ensuring

the availability of qualified contractors.

The reinforcement and augmentation of

these types of efforts through MMM

programs is expected to result in

increased levels of testing and

mitigation of existing homes by the

public and of homes being built to be

radon-resistant.

The ‘‘mitigation measures’’ set forth

in the 1996 SDWA are similar to those

being used in the existing national and

State radon programs. Section 1412

(b)(13)(G)(ii) provides that State MMM

programs may rely on a variety of

‘‘mitigation measures’’ including

‘‘public education, testing, training,

technical assistance, remediation grants

and loans and incentive programs, or

other regulatory or non-regulatory

measures’’. These represent many of the

same strategies that are integral to the

indoor radon program strategy, as well

as those outlined in the 1988 Indoor

Radon Abatement Act.

The risk reduction achieved to date

through the national and State radon

programs has been achieved primarily

through a non-regulatory approach. The

SIRG guidance for implementing a

program also outlines and recommends

indoor radon program priorities,

encourages States to develop narrative

descriptions of how they intend to

address the priority areas, and

encourages the establishment of goals

for awareness, testing and mitigation of

homes and schools, and radon-resistant

new construction. Under SIRG, the

States are required to submit a list of

their activities and workplans for each

project that will be done under the

grant. While EPA’s SIRG guidance

requires a list of program activities, it is

not currently a Federal requirement

under the Indoor Radon Abatement Act

of 1988 or under SIRG that State indoor

radon programs to: (a) publicly set goals

for awareness, testing, mitigation and

new construction; (b) develop and

implement a strategic plan for action

through real estate transactions, new

home construction, testing and fixing

schools, and getting the public to test

and fix their homes; (c) develop and

implement approaches to track and

measure the results of their strategic

plans and activities and report those

results to the public; and (d) directly

involve the public in the development

of the States’ program goals and

strategic plans. EPA is proposing that, in

order to have an approved MMM

program plan, States now be required to

take these steps.

EPA believes this augmentation of

State programs required under the

criteria will result in an increased level

of risk reduction. States will develop

their plans with direct public

participation in setting goals, develop

strategic plans in key areas, and develop

approaches for tracking and measuring

results against goals. EPA also expects

that substantial and constructive public

participation in the development

process of the State’s MMM program

plan is likely to result in a program that

meets the public’s needs and concerns

on an important public health issue, as

well as in greater public awareness of

the health effects of radon and in

increased voluntary action by the public

to address their risks from indoor radon.

Given EPA’s estimate of the expected

increase in the yearly rate of lung cancer

deaths avoided from the current

voluntary program, EPA expects that

State MMM program plans meeting

these four criteria will achieve equal, or

much more likely, greater health risk

reduction benefits.

I. Background on the Existing EPA and

State Indoor Radon Programs

Implementation of EPA’s current

national strategy to reduce public health

risks from radon in indoor air has

focused on using a decentralized

management and risk communication

approach in partnership with States,

local governments and a network of

national organizations; a continuum of

risk reduction strategies; and, a strong

focus on key priorities. Reduction of

indoor radon levels has the potential to

yield very large risk reduction benefits

through pursuit of a wide range of

approaches including the availability of

relatively inexpensive testing,

mitigation, and new construction

techniques to reduce the risk from

indoor radon. National, State, and local

efforts continue to proactively

encourage the public to test and fix their

homes, promote action on radon in

association with real estate transactions,

and promote the construction of new

homes with radon-resistant techniques

through institutional changes such as

local adoption of new construction

standards and codes.

Prior to 1985 the federal government

and only a few States had initiated

activities to address indoor radon

problems. The initial foundation and

scope of State programs was determined

by the different needs of the States. For

example, some Western States

developed programs to assist citizens

living on or near uranium mines or mill

tailings sites. When very high levels of

radon in homes in the area known as the

Reading Prong in the Northeastern U.S.

were discovered in late 1984, the

Agency began to develop and to

implement a coordinated national radon

program. Some Eastern States situated

over the Reading Prong began to

develop strong programs in response to

homes being found with radon levels in

the hundreds and thousands of pCi/L of

air. However, there was no coordinated

government program, or testing and
59266 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

mitigation industry, to address the risks

posed by radon and only a very small

fraction of the public was even aware of

the problem.

Since then, there has been significant

progress in the nation’s program to

promote voluntary public action to

reduce the health risks from radon in

indoor air. EPA’s non-regulatory Radon

Program has established a partnership

between federal, State, local and private

organizations, as well as private

industry, working together on numerous

fronts to promote voluntary radon risk

reduction. This partnership initially

focused programs on increasing public

awareness of the problem and providing

the public with the necessary resources,

including a range of technical guidance

and information, to enable them to

reduce their health risks through

voluntary actions across the nation.

Congress endorsed this strategy and

strengthened the indoor radon program

through the Superfund Amendments

and Reauthorization Act of 1986, and

again in 1988 through passage of the

Indoor Radon Abatement Act. The

Superfund Amendments and

Reauthorization Act of 1986 (SARA)

authorized EPA to conduct a national

assessment of radon in residences,

schools, and workplaces. The 1988

Indoor Radon Abatement Act (IRAA), an

amendment to the Toxic Substances

Control Act. established the overall

long-term goal of reducing indoor radon

levels to ambient outdoor levels,

required the development and

promotion of model standards and

techniques for radon-resistant

construction, and established the State

Indoor Radon Grant program (SIRG).

IRAA also directed EPA to study radon

levels in the U.S., evaluate mitigation

methods to reduce indoor radon,

establish proficiency programs for radon

detection devices and services, develop

training centers, provide the public with

information about radon, and assist

States to develop and implement

programs to address indoor radon.

Recognizing the importance of

working in partnership with the States

and leading national organizations, EPA

developed a decentralized system for

informing the public about the health

risks from radon, consisting primarily of

State and local governments and key

national organizations, with their state

and local affiliates, who serve as sources

of radon information and support

activities to the public. EPA has worked

with the States to help establish and

enhance effective State indoor radon

programs and develop basic State

capabilities needed for assisting the

public in reducing their risk from

indoor radon. EPA developed and

transferred technical guidance on radon

measurement and mitigation to the

States, the private sector, and the

public.

A key initiative in this effort to build

State Radon Programs has been the State

Indoor Radon Grant (SIRG) Program,

which provides funding to help States

develop and operate effective and selfsustaining radon programs. As of

August 1999, forty-five States are

currently participating in the SIRG

program. These grants have been

instrumental in establishing State radon

programs or in helping States expand

their radon programs more quickly than

they otherwise could have.

EPA, the States and national and local

partners are using a mixture of diverse

strategies that range from the more

flexible, such as providing information

to the public to encourage the public to

act, to more prescriptive, such as

providing incentives that give some

advantage for taking action, or to

adopting policies and requirements that

mandate certain actions. As a result,

many initiatives are underway today

both to actively encourage and motivate

homeowners to test and fix their homes

as well as to institutionalize risk

reduction through testing and mitigation

during real estate transactions and

through construction of new homes to

be radon-resistant.

EPA and the States, working with key

national and local organizations, have

developed a wide range of channels for

delivering information to their

members, affiliates and other target

audiences. Many organizations have

their own ‘‘hotlines,’’ journals,

brochures, newsletters, press releases,

radio and television programs, national

conferences, and offer training and

continuing education programs. These

partners collaborate to urge public

action on radon though a wide variety

of strategies including information,

motivation, incentives, and state and

local mandates. The public receives a

consistent message on radon from EPA,

the States, and a number of other key,

respected, and credible sources. Each

target audience, like physicians or

school nurses or local government

officials, becomes in turn a source of

information for new target audiences

like their patients and local

constituents. This approach is

comparable to that used to encourage

people to take various other voluntary

preventive measures to reduce their risk

of various health and safety risks. Some

of the national organizations that EPA

and the States work with include the

American Lung Association, the

National Association of City and County

Health Officials, the National Parent

Teacher Association, the Asian

American and Pacific County Health

Officials, the Association of State and

Territorial Health Officials, the National

Environmental Health Association, the

National Association of County

Officials, the Consumer Research

Council of Consumer Federation of

America, the National Safety Council,

and many others.

Many of the publicly available

information materials are specialized

and designed to encourage specific

actions by certain groups, e.g.,

physicians, homebuilders, real estate

agents, home inspectors, home buyers

and sellers, and many others. As a

result, for example, many home builders

are voluntarily using radon resistant

new construction techniques and some

real estate associations are voluntarily

incorporating the use of radon

disclosure forms into their regular

business practices. Medical and health

care professionals are being educated

about the health risks of radon and are

encouraging their patients to test their

homes for radon as a preventive health

care measure. Public service

announcements by local radio and TV

stations encourage the public to act.

Other public information materials

provide consumers with information on

how to test their homes and what

options they have for mitigating their

radon problem.

Incentive programs and initiatives,

such as free radon test kits, and builder

rebates when builders build homes

radon-resistant, are being implemented.

States and local jurisdictions are also

pursuing a variety of regulatory radon

initiatives, such as requiring schools to

be tested for indoor radon, requiring

disclosure of elevated radon levels in

residential real estate transactions, and

requiring new homes to be built with

radon-resistant new construction

features through building codes. These

strategies and many others are being

used to successfully achieve public

action to reduce the health risks from

indoor radon.

EPA has consulted with scientists,

federal, state and local government

officials, public health organizations,

risk communication experts, and others

to design this program and focus on

radon program strategies which have the

greatest potential for reducing radon

risks through long-term institutional

change. In developing strategies for

reducing radon risks, EPA and the

States have learned from the experience

of other successful national public

health campaigns, such as the

campaigns to promote the use of seat

belts. These campaigns have shown that

significant public action to voluntarily
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reduce health risks can be achieved

from concerted efforts through a variety

of diverse strategies and through the

combined efforts of State and local

governments, public health

organizations, and other public interest

groups, grass roots organizations, and

the private sector.

Program priorities have been

identified to help concentrate and focus

efforts of EPA, the States, and local

organizations, and others on those

activities that are most effective in

achieving the overall mission of indoor

radon risk reduction. Working with a

broad group of stakeholders, EPA

established several key priority areas for

indoor radon. States and cooperative

national organizations have been

focusing many of their efforts and

activities in these areas.

1. Targeting Efforts on the Greatest Risks

First

EPA, the States, and many other

public health organizations recommend

that all homes be tested and all homes

at or above 4 pCi/L be fixed. However,

resources have been more heavily

focused initially in areas where action

produces the most substantial risk

reduction, such as on homes and

schools in the high radon potential areas

and on the increased risk of lung cancer

from indoor radon to current and former

smokers.

2. Promote Radon-Resistant New

Construction

EPA and others encourage programs

to promote voluntary adoption of radonresistant building techniques by

builders and the adoption of radon

construction standards into national,

State and local building codes. Methods

(model standards) that establish

construction techniques for reducing

radon entry in new construction have

been developed and published by EPA

in collaboration with the National

Association of Home Builders. There are

currently over 30 major building

contractors (some are national firms)

who design and construct radon

resistant new homes. It is very costeffective to build new homes radonresistant, especially in higher radon

potential areas. In the existing indoor

radon program, EPA has been

encouraging the States to promote

testing and mitigation in all areas of a

State. EPA has also encouraged the

States to focus on their activities to

promote radon-resistant new

construction on the highest radon

potential areas (Zone 1) where building

homes radon-resistant is most costeffective. However, it is also costeffective to build homes in medium

potential areas (Zone 2), as well as in

‘‘hot’’ spots found in most lower radon

potential areas (Zone 3).

3. Promote Testing and Mitigation

During Real Estate Transactions

Based on the efforts of EPA, the

States, and others, there has been a

steady increase in the number of radon

tests and mitigations voluntarily done

through real estate actions. It is very

cost-effective to test and mitigate

existing homes with elevated indoor

radon levels. Real estate transactions

offer a significant opportunity to

achieve radon risk reduction. In 1993,

EPA published the ‘‘Home Buyer’s and

Seller’s Guide to Radon’’ (USEPA

1993f). Hundreds of thousands of copies

of the ‘‘Home Buyer’s Guide’’ have been

distributed to consumers. The

companion to the ‘‘Home Buyer’s

Guide’’ is the ‘‘Consumer’s Guide to

Radon Reduction’’ (USEPA 1992d)

which provides information on how to

go about reducing elevated radon levels

in a home.

A significant amount of radon testing

and mitigation of existing homes takes

place during real estate transactions

through the combination of home

inspections, real estate transfers, and

relocation services. Many different

groups are in a position to influence

buyers and sellers to test and mitigate

elevated radon levels. This includes

sales agents and brokers, buyers agents,

home inspectors, mortgage lenders,

secondary mortgage lenders, appraisers,

insurance companies, State real estate

licensing commissions, real estate

educators, relocation companies, real

estate press, and others. There are

currently no requirements at the federal,

State, or local level that a house be

tested for indoor radon as part of a real

estate transaction. Many State and local

governments, however, have passed

laws requiring some form of radon

disclosure, although the extent and

detail of these mandatory disclosure

laws varies.

4. Promote Individual and Institutional

Change through Public Information and

Outreach Programs

Because the health risk associated

with indoor radon is controlled

primarily by individual citizens, EPA,

the States and others have developed a

nationwide public information effort to

inform the public about the health risks

from indoor radon and encourage them

to take action. EPA recommends that the

public use EPA-listed or State-listed

radon test devices and hire a trained

and qualified radon contractor to fix

elevated radon levels. Early on, EPA

established voluntary programs to

evaluate the proficiency of these testing

and mitigation service companies to

provide a mechanism for providing the

public with information by publishing

updated lists of firms that pass all

relevant criteria. Many States have

established their own proficiency

programs. To help support these efforts,

EPA established four self-sustaining

Regional Radon Training Centers across

the country to train testing and

mitigation contractors, State personnel,

and others in radon measurement,

mitigation, and prevention techniques.

In 1998, the Conference of Radiation

Control Program Directors (CRCPD),

representing State radiation officials,

initiated a pilot program through the

National Environmental Health

Association to establish a privatized

national proficiency program to replace

EPA’s proficiency program which is

terminating.

VII. What Are the Requirements for

Addressing Radon in Water and Radon

in Air? MCL, AMCL and MMM

A CWS must monitor for radon in

drinking water in accordance with the

regulations, as described in Section VIII

of this preamble, and report their results

to the State. If the State determines that

the system is in compliance with the

MCL of 300 pCi/L, the CWS does not

need to implement a MMM program (in

the absence of a State program), but

must continue to monitor as required.

As discussed in Section VI, EPA

anticipates that most States will choose

to develop a State-wide MMM program

as the most cost-effective approach to

radon risk reduction. In this case, all

CWSs within the State may comply with

the AMCL of 4000 pCi/L. Thus, EPA

expects the vast majority of CWSs will

be subject only to the AMCL. In those

instances where the State does not

adopt this approach, the proposed

regulation provides the following

requirements:

A. Requirements for Small Systems

Serving 10,000 People or Less

The EPA is proposing that small CWS

serving 10,000 people or less must

comply with the AMCL, and implement

a MMM program (if there is no state

MMM program). This is the cut-off level

specified by Congress in the 1996

Amendments to the Safe Drinking Water

Act for small system flexibility

provisions. Because this definition does

not correspond to the definitions of

‘‘small’’ for small businesses,

governments, and non-profit

organizations previously established

under the RFA, EPA requested comment

on an alternative definition of ‘‘small

entity’’ in the preamble to the proposed
59268 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

Consumer Confidence Report (CCR)

regulation (63 FR 7620, February 13,

1998). Comments showed that

stakeholders support the proposed

alternative definition. EPA also

consulted with the SBA Office of

Advocacy on the definition as it relates

to small business analysis. In the

preamble to the final CCR regulation (63

FR 4511, August 19, 1998), EPA stated

its intent to establish this alternative

definition for regulatory flexibility

assessments under the RFA for all

drinking water regulations and has thus

used it for this radon in drinking water

rulemaking. Further information

supporting this certification is available

in the public docket for this rule.

EPA’s regulation expectation for small

CWSs is the MMM and AMCL because

this approach is a much more costeffective way to reduce radon risk than

compliance with the MCL. (While EPA

believes that the MMM approach is

preferable for small systems in a nonMMM State, they may, at their

discretion, choose the option of meeting

the MCL of 300 pCi/L instead of

developing a local MMM program). The

CWSs will be required to submit MMM

program plans to their State for

approval. (See Sections VI.A and F for

further discussion of this approach).

SDWA Section 1412(b)(13)(E) directs

EPA to take into account the costs and

benefits of programs to reduce radon in

indoor air when setting the MCL. In this

regard, the Agency expects that

implementation of a MMM program and

CWS compliance with 4000 pCi/L will

provide greater risk reduction for indoor

radon at costs more proportionate to the

benefits and commensurate with the

resources of small CWSs. It is EPA’s

intent to minimize economic impacts on

a significant number of small CWSs,

while providing increased public health

protection by emphasizing the more

cost-effective multimedia approach for

radon risk reduction.

B. Requirements for Large Systems

Serving More Than 10,000 People

The proposal requires large

community water systems, those serving

populations greater than 10,000, to

comply with the MCL of 300 pCi/L

unless the State develops a State-wide

MMM program, or the CWSs develops

and implements a MMM program

meeting the four regulatory

requirements, in which case large

systems may comply with the AMCL of

4,000 pCi/L. CWSs developing their

own MMM plans will be required to

submit these plans to their State for

approval.

C. State Role in Approval of CWS MMM

Program Plans

The SDWA provides that EPA will

approve CWS MMM program plans.

EPA has developed criteria to be used

for approving MMM programs. EPA will

review and approve State MMM

program plans. CWS MMM program

plans that address the criteria and are

approved by the State are deemed

approved by EPA. The proposed rule

requires States that do not have a Statewide MMM program, as a condition of

primacy for the radon regulation, to

review MMM program plans submitted

by CWSs and to approve plans meeting

the four criteria for MMM programs

discussed in Section VI of this

preamble, including providing notice

and opportunity for public comment on

CWS MMM program plans. Under

Section 1412(b)(13)(G)(vi) of SDWA,

MMM program plans submitted by

CWSs are to be subject to the same

criteria and conditions as State MMM

program plans. EPA will review CWS

MMM program plans in non-primacy

States, Tribes and Territories that do not

have a state-wide MMM program, and

approve them if they meet the four

required criteria.

D. Background on Selection of MCL and

AMCL

The SDWA directs that if the MCL for

radon is set at a level more stringent

than the level in drinking water that

would correspond to the average

concentration of radon in outdoor air,

EPA must also set an alternative MCL at

the level corresponding to the average

concentration in outdoor air. Consistent

with this requirement, EPA is proposing

to set the AMCL at 4000 pCi/L. This

level is based on technical and scientific

guidance contained in the NAS Report

(NAS 1999b) on the water-to-air transfer

factor of 10,000 pCi/L in water to 1 pCi/

L in indoor air and the average outdoor

radon level of 0.4 pCi/L.

The SDWA generally requires that

EPA set the MCL for each contaminant

as close as feasible to the MCLG, based

on available technology and taking costs

to large systems into account. The 1996

amendments to the SDWA added the

requirement that the Administrator

determine whether or not the benefits of

a proposed maximum contaminant level

justify the costs based on the HRRCA

required under Section 1412(b)(3)(C).

They also provide new discretionary

authority to 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

(SDWA section 1412(b)(6)(A)).

EPA is proposing to set the MCL at

300 pCi/L, in consideration of several

factors. First, the Agency considered the

general statutory requirement that the

MCL be set as close as feasible to the

MCLG of zero (SDWA section

1412(b)(4)), and its responsibility to

protect public health. In addition, the

radon-specific provisions of the

amendments provide that, in

promulgating a radon standard, the

Agency take into account the costs and

benefits of programs to control indoor

radon (SDWA 1412(b)(13)(E). Although

EPA believes that an MCL of 100 pCi/

L would be feasible, EPA believes that

consideration of the costs and benefits

of indoor radon control programs allows

the level of the MCL to be adjusted to

a less stringent level than the Agency

would set using the SDWA feasibility

test. The proposed MCL of 300 pCi/L

takes into account and relies on the

unique conditions of this provision and

the reality it reflects that the great

preponderance of radon risk is in air,

not water, and the much more costeffective alternative to water treatment

is to address radon in indoor air through

the MMM program. The Agency

recognizes that controlling radon in air

will substantially reduce human health

risk in more cost-effective ways than

spending resources to control radon in

drinking water. If most states adopted

the MMM/AMCL option, EPA estimates

the combined costs for treatment of

water at systems exceeding the AMCL,

developing a MMM program, and

implementing measures to get risk

reduction equivalent to national

compliance with the MCL (62 avoided

fatal cancer cases and 4 avoided nonfatal cancer cases per year) at $80

million, which is substantially less than

the $407.6 million cost of achieving the

MCL. EPA expects that most states will

adopt the AMCL/MMM program option

While EPA believes it is appropriate

to acknowledge the more cost-effective

control program to a certain extent in

setting the MCL, the Agency does not

believe the cost-effectiveness is the sole

determining factor. Rather, EPA believes

the absolute level of risk to which

members of the public may be exposed

is also a key consideration in

determining a standard that is protective

of public health.

The Agency proposed an MCL of 300

pCi/L in 1991 based, in part, on its

assessment of the health risk posed by

radon in drinking water. It should be

noted that the overall magnitude of risk

estimated by the Agency at that time is

in agreement with the overall risk of

radon in drinking water currently

estimated by the National Academy of

Sciences (NAS 1999b). The Agency has
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a long-standing policy that drinking

water standards should limit risk to

within a range of approximately 10 ¥4 to

10 ¥6 and is thus proposing to use the

flexibility provided by the authority in

1412(b)(13)(E) to propose an MCL of 300

pCi/L, which is approximately at the

upper bound of the Agency’s traditional

risk range used for the drinking water

program (representing an estimated 2

fatal cancers per 10,000 persons).

As noted earlier, the Administrator

must publish a determination as to

whether the benefits of the proposed

MCL justify the costs, based on the

Health Risk Reduction and Cost

Analysis prepared in accordance with

SDWA § 1412(b)(3)(C). Accordingly, the

Administrator has determined that the

benefits of the proposed MCL of 300

pCi/L justify the costs. The benefits of

the proposed MCL, include about 62

avoided fatal lung cancer cases and 4

avoided non-fatal lung cancer cases

annually. EPA has used a valuation of

$5.8 million ($1997) to value the

avoided fatal cancers and a valuation of

$536,000 ($1997) to value the avoided

non-fatal cancers. Multiplying these

valuations by the estimated cancer cases

avoided (62 fatal, 3.6 non-fatal) yields a

benefits estimate of $362 million per

year. The cost to achieve national

compliance with an MCL of 300 pCi/L

is estimated at $407.6 million per year.

EPA expects the actual cost of the

proposed rule to be significantly lower,

since the expectation is that most

systems will not need to comply with

the MCL of 300 pCi/L. Costs would be

about $80 million per year if the AMCL/

MMM option is widely adopted by

States.

There are also some potential nonquantified benefits, including customer

peace of mind from knowing drinking

water has been treated for radon and

reduced treatment costs for arsenic for

some water systems that have problems

with both contaminants, and nonquantified costs, including increased

risks from exposure to disinfection

byproducts, permitting and treatment of

radon off-gassing, anxiety on the part of

residents near treatment plants and

customers who may not have previously

been aware of radon in their water, and

safety measures necessary to protect

treatment plant personnel from

exposure to radiation. However, in this

case it is not likely that accounting for

these non-quantifiable benefits and

costs quantitatively would significantly

alter the overall assessment. Taking both

quantified and non-quantified benefits

into account, EPA has determined that

the costs are justified by the benefits.

Accordingly, the new authority to set a

less stringent MCL if benefits do not

justify costs is not applicable and has

not been used in this proposal.

Although the central tendency

estimate of monetized costs exceeds the

central tendency estimate of monetized

benefits, the determination that benefits

justify costs is consistent with the

legislative history of this provision,

which makes clear that this

determination whether benefits

‘‘justify’’ costs is more than a simple

arithmetic analysis of whether benefits

‘‘exceed’’ or ‘‘outweigh’’ costs. The

determination must also ‘‘reflect the

non-quantifiable nature of some of the

benefits and costs that may be

considered. The Administrator is not

required to demonstrate that the dollar

value of the benefits are greater (or

lesser) than the dollar value of the

costs.’’ [Senate Report 104–169 on S.

1316, p. 33] The determination is based

on the analysis conducted under SDWA

§ 1412(b)(3)(C), in the Health Risk

Reduction and Cost Analysis (HRRCA)

published for public comment on

February 26, 1999 (64 FR 9559), revised

in response to public comment, and

available as part of the Regulatory

Impact Analysis (1999n) in the public

docket to support this rulemaking. The

costs and benefits of the proposed rule,

and the methodologies used to calculate

them, are discussed in detail in section

XII of this preamble and in the

Regulatory Impact Analysis (1999n).

In making this determination, EPA

also considered the special nature of the

radon standard, which provides an

alternate MCL of 4000 pCi/L for states

or water systems that adopt a MMM

program designed to produce equal or

greater risk reduction benefits to

compliance with the MCL by promoting

voluntary public action to mitigate

radon in indoor air. As noted

previously, mitigation of radon in

indoor air is much more cost-effective

than mitigation of radon in drinking

water. If most states adopted the MMM/

AMCL option, EPA estimates the

combined costs for treatment of water at

systems exceeding the AMCL,

developing a MMM program, and

implementing measures to get risk

reduction equivalent to national

compliance with the MCL (62 avoided

fatal cancer cases and 4 avoided nonfatal cancer cases per year) at $80

million, which is substantially less than

the $407.6 million cost of achieving the

MCL.

In its valuation of costs and benefits

for the MMM program, EPA has

assumed that adopting the MMM

approach will achieve only benefits

equivalent to those for meeting the MCL

and has calculated the costs and

benefits of the proposed rule on this

basis. However, EPA expects that

adoption of MMM programs will be

widespread as a result of this rule and

that the actual benefits realized will be

far greater than those associated with

meeting the MCL. In addition, EPA fully

expects most States to follow the MMM

approach, therefore CWSs below the

AMCL will incur minimal costs and a

much smaller subset of CWSs will incur

costs to meet the AMCL. Thus, costs for

meeting the MCL are a theoretical worst

case scenario which the Agency believes

will not occur, particularly since the

regulatory expectation for water systems

serving 10,000 people or fewer would be

that they meet the 4000 pCi/L AMCL,

along with implementation of a local

MMM program. Although in some cases

small CWSs may choose to meet the

MCL of 300 pCi/L through water

treatment, this is voluntary and not a

requirement of the proposed regulation.

The Agency also considered the costs,

benefits, and risk reduction potential of

radon levels at 100 pCi/l, 500 pCi/L,

1000 pCi/L, 2000 pCi/L and 4000 pCi/

L. As table VII.1 illustrates, the costs

and benefits increase as the radon level

increases. The quantified costs

somewhat exceed the quantified

benefits at each level, but the benefitcost ratios are similar. However, the

difference between costs and benefits

becomes somewhat larger as the various

MCL options become more stringent,

with the largest difference at 100 pCi/L.

When the uncertainty of the estimates is

factored in, there is overlap in the

benefit and cost estimates at all

evaluated options. For more information

on this analysis, please refer to the

Regulatory Impact Analysis (RIA) for

this proposal (USEPA, 1999n).
59270 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

TABLE VII.1.—EVALUATION OF RADON LEVELS

Radon level

(pCi/L)

Fatal cancer

cases

avoided

Individual fatal lifetime

cancer risk

Cost per

fatal cancer

case avoided

($M)

Total national

costs 1

$M

Monetized

benefits 1

$M

Benefit-cost

ratio

4000 ............................................................... 2.9 26.8 in 10,000 ........... 14.9 43.1 17.0 0.4

2000 ............................................................... 7.3 13.4 in 10,000 ........... 9.5 69.7 42.7 0.6

1000 ............................................................... 17.8 6.7 in 10,000 ............. 7.3 130.5 103 0.8

500 ................................................................. 37.6 3.35 in 10,000 ........... 6.8 257.4 219 0.9

300 ................................................................. 62.0 2.0 in 10,000 ............. 6.6 407.6 362 0.9

100 ................................................................. 120.0 0.67 in 10,000 ........... 6.8 816.2 702 0.9

1Water Mitigation only; assuming 100% compliance with MCL. Source: revised HRRCA.

Some commenters recommended that

EPA give serious consideration to

setting an MCL at the AMCL level (4000

pCi/L), or at least at a level substantially

above 300 pCi/L, in order to control

radon levels in drinking water at a level

more comparable to outdoor background

levels. This approach was also

discussed by the Small Business

Advocacy Review Panel convened for

this rule under the RFA as amended by

SBREFA. (A copy of the Panel’s final

report is available in the docket for this

rule making, (USEPA, 1998c).)

As noted earlier, EPA’s interpretation

of the standard-setting requirements of

the SDWA for radon are that they rely

primarily upon the general standardsetting provisions for National Primary

Drinking Water Regulations, with some

additional radon-specific provisions.

The general provisions require that the

MCL be set as close as feasible to the

MCLG. The radon-specific provisions

direct the Administrator to take into

account the costs and benefits of control

programs for radon from other sources.

As discussed, EPA is interpreting these

general and radon-specific authorities to

propose an MCL above the feasible

level, near the upper end of the risk

range traditionally used by the Agency

in setting drinking water standards. In

addition, EPA believes that the

extensive statutory detail enacted on

multimedia mitigation illustrates a

congressional preference for costeffective compliance through the

AMCL/MMM program approach. EPA

notes that the equal or greater risk

reduction required to be achieved

through the AMCL/MMM option would

be diminished as the MCL approaches

the AMCL of 4,000 pCi/L and that fewer

States and CWSs would select this

option. Further, the AMCL/MMM

approach would be eliminated entirely

if the MCL were set at the AMCL.

As noted previously, EPA believes the

proposed MCL of 300 pCi/L, in

combination with the proposed AMCL

and MMM approach, accurately and

fully reflects the SDWA provisions. The

Agency recognizes , however, that some

stakeholders may have strong views

about the appropriateness of setting an

MCL at a higher level. Accordingly, EPA

requests comment on the option of

setting the MCL closer to or at the

AMCL level of 4000 pCi/L. In this

connection, the Agency also requests

comments on and the rationale for how

such alternative options could be legally

supported under the SDWA and in the

record for this rulemaking, in light of

the considerations EPA has applied for

the MCL it proposes.

EPA solicits comment on the

proposed MCL and AMCL and the

Agency’s rationale, and on other

appropriate MCLs given these

considerations, and the rationale for

alternative levels. In the final rule, the

Agency may select a higher or lower

option from those analyzed in the

HRRCA for the final radon rule without

further public comment.

E. Compliance Dates

The proposed time line for

compliance with the radon rule is

described next and illustrated in Figure

VII.1.

BILLING CODE 6560–60–P
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59271

BILLING CODE 6560–50–C
59272 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

States are required to submit their

primacy revision application packages

by two years from the date of

publication of the final rule in the

Federal Register. For States adopting

the AMCL, EPA approval of a State’s

primacy revision application is

contingent on submission of and EPA

approval of the State’s MMM program

plan. Therefore, EPA is proposing to

require submission of State-wide MMM

program plans as part of the complete

and final primacy revision application.

This will enable EPA to review and

approve the complete primacy

application in a timely and efficient

manner in order to provide States with

as much time as possible to begin to

implement MMM programs. In

accordance with Section 1413(b)(1) of

SDWA and 40 CFR 142.12(d)(3), EPA is

to review primacy applications within

90 days. Therefore, although the SDWA

allows 180 days for EPA review and

approval of MMM program plans, EPA

expects to review and approve State

primacy revision applications for the

AMCL, including the State-wide MMM

program plan, within 90 days of

submission to EPA.

EPA is proposing that CWSs begin

their initial monitoring requirements

(one year of quarterly monitoring) for

radon by 3 years after publication of the

final rule in the Federal Register, except

for CWSs in States that submit a letter

to the Administrator committing to

develop an MMM program plan in

accordance with Section 1412

(b)(13)(G)(v). For CWSs in these States,

one year of quarterly monitoring is

proposed to begin 4.5 years after

publication of the final rule. The

proposed rule allows systems to use

grandfathered data collected after the

proposal date to satisfy the initial

monitoring requirements provided the

monitoring and analytical methods

employed satisfy the regulations set

forth in the rule and the State approves.

Systems opting to conduct early

monitoring will not be considered in

violation of the MCL/AMCL until after

the initial monitoring period applicable

to their State (i.e., 4 years after

publication of the final rule, 5.5 years

after publication of the final rule).

The routine and reduced monitoring

requirements were developed to be

consistent with the Standardized

Monitoring Framework (SMF) and the

Phase II/V monitoring schedule. EPA

believes this is valuable for States and

systems by providing sampling

efficiency and organization, therefore,

EPA has tried to adapt the compliance

dates so that States and systems can

make a smooth transition into the SMF

following the initial monitoring

requirements. The necessity to complete

the initial monitoring in a timely

manner is driven by the need for

systems in non-MMM States to evaluate

their compliance options, including

development of a local MMM program

and compliance with the AMCL), and

for systems in MMM States to ensure

compliance with the AMCL.

EPA feels it is important to set time

constraints on implementation of the

MMM plans to ensure the equal or

greater risk reduction resulting from

multimedia mitigation. Therefore, the

rule must allow the systems in nonMMM States enough time to develop

their MMM program plan with technical

assistance from the State and submit the

plan for State approval. In addition, the

State must have sufficient time to

review and approve the local plans. If

the compliance determination for a

system in a non-MMM State exceeds the

MCL during the initial monitoring

period, the proposed rule requires these

systems to notify the State of their

intention to develop a local MMM

program at the completion of initial

monitoring, 4 years after publication of

the final rule. The local MMM program

plans must be submitted to the State for

approval by 5 years after of publication

of the final rule (i.e., 12 months after the

completion of initial monitoring) and

the States have 6 months from the

submittal date to review and approve or

disapprove the plan. The system will

begin implementation of their MMM

program 5.5 years after publication of

the final rule (i.e., 1.5 years after the

completion of initial monitoring). If the

State fails to review and disapprove the

local MMM program in the time

allowed, the system will begin

implementation of the submitted plan. If

the system fails to comply with these

compliance dates, a MCL violation will

apply from the date of exceedence. If the

compliance determination for a system

choosing to comply with the MCL

exceeds the MCL following the

completion of the initial monitoring

period, the system will have the option

to submit a local MMM plan to the State

within 1 year from the date of the

exceedence and begin implementation

1.5 years from the date of the

exceedence or incur a MCL violation.

Implementation of State-wide MMM

programs must begin 3 years after

publication of the final rule, unless the

State submits a letter to the

Administrator committing to develop an

MMM program plan in accordance with

Section 1412 (b)(13)(G)(v) of the SDWA.

States submitting this letter must

implement their State-wide MMM

program plan by 4.5 years after

publication of the final rule. EPA feels

it is extremely important that the MMM

program plans be completed on a

schedule that allows States sufficient

time to begin implementation by the

compliance date to ensure that equal or

greater risk reduction benefits are

provided.

EPA recognizes potential issues may

arise as a result of the proposed initial

monitoring schedule. The potential

issues include lab capacity and a

temporary deviation from the SMF

schedule. EPA is requesting comment

on alternatives to avoid or lessen the

impact of these issues and other issues

not listed here.

EPA considers the proposed

monitoring schedule to be acceptable

since the proposed rule affects one

contaminant and applies to a smaller

universe of water systems (NTNCWSs,

transient systems, and CWSs relying

solely on surface water are not covered

by the rule) which decreases the number

of systems effected, and therefore

lessens the impacts of the potential

issues. An alternative initial monitoring

scenario which was considered would

specify early monitoring requirements

for systems serving more than 10,000

people. This scenario would put

additional burden on the States and

systems to monitor early and it would

not substantially ease the workload

since the number of systems serving

greater than 10,000 that use

groundwater or groundwater under the

direct influence of surface water is

relatively small.

Initial monitoring could be phased in

over a period of two or three years, but

EPA does not feel it is appropriate to

extend the initial monitoring period due

to the necessity to evaluate the need to

develop and implement local MMM

program plans. In MMM States, systems

must be in compliance with the AMCL

in a timely manner to ensure the

maximum risk reduction.

In consideration of all these factors,

EPA is proposing to require the initial

monitoring over a one-year period as

specified earlier. However, systems

opting to conduct early monitoring will

not be considered in violation of the

MCL/AMCL until after the initial

monitoring period applicable to their

State (i.e., 4 years after publication of

the final rule, 5.5 years after publication

of the final rule). However, CWSs opting

to conduct early monitoring will not be

considered in violation of the MCL/

AMCL until after the initial monitoring

period applicable to their State (i.e., 4

years after publication of the final rule,

5.5 years after publication of the final

rule. It is EPA’s strong recommendation

that all States choose to adopt the

AMCL and implement an MMM
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59273

program. But some States may elect to

adopt the MCL or may decide later to

adopt the AMCL/MMM approach. In

these states, the initial monitoring will

be required to begin by 3 years after

publication of the final rule, whereas in

States submitting the 90-day letter

committing to develop an MMM

program plan will begin initial

monitoring 4.5 years after publication of

the final rule.

VIII. What Are the Requirements for

Testing for and Treating Radon in

Drinking Water?

A. Best Available Technologies (BATs),

Small Systems Compliance

Technologies (SSCTs), and Associated

Costs

1. Background

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

that each national primary drinking

water regulation which establishes an

MCL shall list the technology, treatment

techniques, and other means which the

Administrator finds to be feasible for

purposes of meeting the MCL. In

addition, the Act states that EPA shall

list, if possible, affordable small systems

compliance technologies (SSCTs) that

are feasible for the purposes of meeting

the MCL. In order to fulfill these

requirements, EPA has identified best

available technologies (BAT) and SSCTs

for radon.

(a) Proposed BAT. Technologies are

judged to be BAT when they are able to

satisfactorily meet the criteria of being

capable of high removal efficiency;

having general geographic applicability,

reasonable cost, and a reasonable

service life; being compatible with other

water treatment processes; and

demonstrating the ability to bring all of

the water in a system into compliance.

The Agency proposes that, of the

technologies capable of removing radon

from source water, only aeration fulfills

these requirements of the SDWA for

BAT determinations for this

contaminant. The full range of technical

capabilities for this proposed BAT is

discussed in the EPA Technologies and

Costs document for radon (USEPA

1999h). Table VIII.A.1 summarizes the

BAT findings by EPA for the removal of

the subject drinking water

contaminants, including a summary of

removal capabilities.

TABLE VIII.A.1—PROPOSED BAT AND

ASSOCIATED CONTAMINANT REMOVAL EFFICIENCIES

High Performance Aeration 1.Up to 99.9% Removal.

Note: (1) High Performance Aeration is defined as the group of aeration technologies

that are capable of being designed for high

radon removal efficiencies, i.e., Packed Tower

Aeration, Multi-Stage Bubble Aeration and

other suitable diffused bubble aeration technologies, Shallow Tray and other suitable Tray

Aeration technologies, and any other aeration

technologies that are capable of similar high

performance.

Granular activated carbon (GAC) can

also remove radon from water, and was

evaluated as a potential BAT and a

potential small systems compliance

technology for radon. Since GAC

removes radon less efficiently than it

does organic contaminants, it generally

requires designs that use larger

quantities of carbon per volume of water

treated to remove radon compared to

contaminants for which GAC is BAT.

This requirement for larger carbon

amounts translates to much higher

treatment costs for GAC radon removal.

In fact, full-scale application of GAC for

radon removal has been limited to

installations at the household point-ofentry and for centralized treatment for

very small communities (AWWARF

1998a). EPA has determined that the

requirements for radon removal render

it infeasible for large municipal

treatment systems, and it is therefore

not considered a BAT for radon.

However, GAC and point-of-entry (POE)

GAC may be appropriate for very small

systems under some circumstances, as

described next (USEPA 1999h,

AWWARF 1998a, AWWARF 1998b).

(b) Proposed Small Systems

Compliance Technologies. The 1996

Amendments to SDWA recognize that

BAT determinations may not address

many of the problems faced by small

systems. In response to this concern, the

Act specifically requires EPA to make

technology assessments relevant to the

three categories of small systems

respectively for both existing and future

regulations. These requirements are in

addition to EPA’s obligation, unchanged

by the SDWA as amended in 1996, to

designate BAT. The three populationserved size categories of small systems

defined by the 1996 SDWA are:

10,000—3,301 persons, 3,300—501

persons, and 500—25 persons. These

evaluations include assessments of

affordability and technical feasibility of

treatment technologies for each class of

small system. Table VIII.A.2, ‘‘Proposed

Small Systems Compliance

Technologies (SSCTs) and Associated

Contaminant Removal Efficiencies’’,

lists the proposed small systems

compliance technologies for radon and

summarizes EPA’s findings regarding

affordability and technical feasibility for

the evaluated technologies. EPA has

interpreted the SSCTs as equivalent to

BATs under Section 1415 of the Act, for

the purposes of small systems (those

serving 10,000 persons or fewer)

applying to primacy agencies for

Section 1415(a) variances.

TABLE VIII.A.2.— PROPOSED SMALL SYSTEMS COMPLIANCE TECHNOLOGIES (SSCTS) 1 AND ASSOCIATED CONTAMINANT

REMOVAL EFFICIENCIES

Small systems compliance technology Affordable listed small

systems categories 2 Removal efficiency

Operator

level required 3

Limitations

(see

footnotes)

Packed Tower Aeration (PTA) ........... All Size Categories ............................ 90– > 99.9% Removal ....................... Intermediate (a)

High Performance Package Plant

Aeration (e.g., Multi-Stage Bubble

Aeration, Shallow Tray Aeration).

All Size Categories ............................ 90– > 99.9% Removal ....................... Basic to Intermediate.

(a)

Diffused Bubble Aeration ................... All Size Categories ............................ 70 to > 99% removal ......................... Basic ............ (a, b)

Tray Aeration ...................................... All Size Categories ............................ 80 to > 90% ....................................... Basic ............ (a, c)

Spray Aeration .................................... All Size Categories ............................ 80 to > 90% ....................................... Basic ............ (a, d)

Mechanical Surface Aeration ............. All Size Categories ............................ > 90% ................................................ Basic ............ (a, e)

Centralized granular activated carbon May not be affordable, except for

very small flows.

50 to > 99% Removal ....................... Basic ............ (f)
59274 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

TABLE VIII.A.2.— PROPOSED SMALL SYSTEMS COMPLIANCE TECHNOLOGIES (SSCTS) 1 AND ASSOCIATED CONTAMINANT

REMOVAL EFFICIENCIES—Continued

Small systems compliance technology Affordable listed small

systems categories 2 Removal efficiency

Operator

level required 3

Limitations

(see

footnotes)

Point-of-Entry (POE) granular activated carbon.May be affordable for systems serving fewer than 500 persons..50 to > 99% Removal ....................... Basic ............ (f, g)

Notes: 1The Act (Section 1412(b)(4)(E)(ii)) specifies that SSCTs must be affordable and technically feasible for small systems. 2This section 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. 3From National Research Council. Safe Water from Every Tap: Improving Water Service to Small Communities. National Academy Press.

Washington, DC. 1997.

Limitations: (a) Pre-treatment to inhibit fouling may be needed. Post-treatment disinfection and/or corrosion control may be needed. (b) May not be as efficient as other aeration technologies because it does not provide for convective movement of the water, which reduces the

air:water contact. It is generally used in adaptation to existing basins. (c) Costs may increase if a forced draft is used. Slime and algae growth can be a problem, but may be controlled with chemicals, e.g., copper

sulfate or chlorine. (d) In single pass mode, may be limited to uses where low removals are required. In multiple pass mode (or with multiple compartments), higher removals may be achieved. (e) May be most applicable for low removals, since long detention times, high energy consumption, and large basins may be required for larger

removal efficiencies. (f) Applicability may be restricted to radon influent levels below around 5000 pCi/L to reduce risk of the build-up of radioactive radon progeny.

Carbon bed disposal frequency should be designed to allow for standard disposal practices. If disposal frequency is too long, radon progeny, radium, and/or uranium build-up may make disposal costs prohibitive. Proper shielding may be required to reduce gamma emissions from the GAC

unit. GAC may be cost-prohibitive except for very small flows. (g) When 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.

(c) Approaches for Listing Small

Systems Compliance Technologies

(SSCTs). EPA has considered several

options for the listing of SSCTs in the

proposed rule for radon. The issue is

how to list SSCTs with BAT in the rule,

while at the same time allowing for

flexible and timely updates to the list of

SSCTs in the future.

EPA would like to establish a

procedure that allows SSCT lists to be

updated by guidance, rather than

through the more resource intensive and

time-consuming process of rule-making.

For example, under today’s proposal,

EPA is including SSCT lists in the rule.

This approach fully satisfies the

requirements in Section 1412(b)(4)E(ii)

of the Act, which states that EPA shall

include SSCTs in lists of BAT for

meeting the MCL. Since BATs are

explicitly listed in rules, it is consistent

to explicitly list SSCTs. Also, Section

1415(a) of the Act requires that BAT be

proposed and promulgated with

NPDWRs to satisfy the provisions for

‘‘general variances’’ (variances under

Section 1415(a)); therefore, SSCTs must

be listed in the rule if small systems are

to be allowed to use them as BAT in

satisfying the provisions for general

variances.

Regarding updates to the list of

SSCTs, Section 1412(b)(9) of the Act

states that EPA shall review and revise,

as appropriate, all promulgated

NPDWRs every six years. However,

since revisions of NPDWRs follow the

normal rule-making process of

proposing, taking public comment, and

finalizing the rule, the process can be

very time-consuming. While EPA

believes that this six year review cycle

is sufficient for updates to lists of BAT,

it is unlikely to be sufficient for updates

to lists of SSCTs, since recent

improvements in package plant

technologies, POE/POU devices, and

remote monitoring/control technologies

have been fairly rapid and future

improvements seem imminent. For this

reason, EPA seeks comment on this

approach or alternate approaches that

would allow for more timely updates to

the list of SSCTs.

In support of an approach to SSCT list

updates that is less formal and more

expeditious than rulemaking, EPA notes

that new Section 1412(b)(4)(E)(iv)

allows the Administrator, after

promulgating an NPDWR, to

‘‘supplement the list of technologies

describing additional or new or

innovative treatment technologies that

meet the requirements of this paragraph

for categories of small public water

systems.’’ This provision does not

contain any reference to or require

rulemaking to update the SSCT list, in

contrast with the earlier 1994 House

version (in H.R. 3392) of this provision

that specifically required revisions of

the list to be made ‘‘by rule.’’

Under one alternative, EPA would

publish only an initial list of SSCTs

with the BAT list in 40 CFR 141.66. EPA

would also state in the rule that updates

to the list of SSCTs would be done

through guidance published in the

Federal Register or through updates to

the SSCT guidance manual. This

process would be consistent with the

process already used for listing SSCTs

for the currently regulated drinking

water contaminants (USEPA 1998g). A

similar alternative approach would

simply ‘‘list’’ SSCTs in Section 141.66

by referencing EPA guidance, which

would be published separately and

which could be updated periodically as

needed outside of the normal rulemaking process. Finally, EPA could

publish both the initial list and the

updates solely in a Federal Register

notice or as guidance; however, under

this last approach, only the promulgated

BAT listed in the rule (which would not

include SSCTs) would be available for

small systems seeking a general variance

under Section 1415(a) of the Act. EPA

solicits comments on the suggested

approaches for the listing of SSCTs and

on the equivalency of SSCTs with BAT

for the purposes of small systems

applying for variances under Section

1415 of the Act.

(d) Small Systems Affordability

Determinations. The affordability

determinations that are used for listing

SSCTs are discussed in detail in recent

EPA publications (USEPA 1998i,

USEPA 1998e). It should be noted that

aeration is one of the least expensive

treatment technologies for drinking

water (USEPA 1993d, NRC 1997) and

has been determined to be affordable for

all three small systems size categories.

For the smallest size category (serving

25 to 500 persons), EPA cost estimates

indicate that typical annual household
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59275

costs for aeration (80% removal

efficiency, with disinfection and scaling

inhibitor) are $190 per household per

year ($/HH/yr). For systems installing

aeration only, household costs for the

smallest system size category are $114

per household per year. Case studies

(n=9, USEPA 1999h) for systems with

aeration serving between 25 and 500

persons showed annual household costs

ranging from $5 to $97 per household

per year, with an average of $45 per

household per year. Costs reported in

these case studies included all pre- and

post-treatments added with aeration.

The ‘‘national average per household

cost’’ estimated in the Regulatory

Impact Analysis is $260 per household

per year for 25–500 persons. This

average per household cost is higher

than the estimated per household costs

for systems using aeration since these

average costs include not only aeration,

but also the more expensive compliance

alternatives (GAC, regionalization, and

‘‘high side’’ PTA). Note that the cost for

the 25–500 category is a weighted

average of the per household costs for

the 25–100 and 101–500 categories

reported in Table 7–2 of the Regulatory

Impact Analysis. Also note that

monitoring costs of approximately $4.00

per household per year ($270 per

system) are included in the national

average per household costs, but not in

the aeration treatment per household

costs reported.

Granular activated carbon (GAC) may

be affordable only for very small flows.

EPA’s GAC-COST model estimates

indicate that GAC may not be affordable

for the smallest size category (25–500

persons served) in whole. Annual

household costs are estimated to be

approximately $800 to > $1000 per

household per year. However, case

studies of small systems using GAC to

remove radon for very small flows

(populations served < 100 persons)

show annual household costs ranging

from $46 to $77 per household per year.

The large discrepancy between modeled

costs and full-scale case study costs is

probably due to the fact that the model

design assumptions are more typical of

larger systems, whereas the designs

used in the case studies are much

simpler. The American Water Works

Association Research Foundation

(AWWARF 1998a) similarly concludes

that EPA’s cost estimates for radon

removal by GAC are over-estimates

(ibid., p. 190) and that GAC can be cost

competitive with aeration for very small

systems (ibid., Chapter 8). Examples of

estimates of POE-GAC capital costs are

shown in the next section, ‘‘Treatment

Costs’’.

2. Treatment Costs: BAT, Small Systems

Compliance Technologies, and Other

Treatment

(a) Modeled Treatment Unit Costs.

Total production costs associated with

the various technological options for

radon reduction, such as packed tower

aeration and diffused bubble aeration

installations, have been examined

(USEPA 1999h). For systems that are

currently disinfecting, ninety-nine

percent reduction of radon by PTA is

estimated to cost from $2.48/kgal

(dollars per 1,000 gallons treated) for the

smallest systems, defined as those

serving 100 persons or fewer, to $ 0.12/

kgal for large systems, defined as those

serving up to 1,000,000 persons. Eighty

percent reduction of radon by PTA

without disinfection is estimated to

range from $2.10/kgal to $0.08/kgal for

the same system sizes. For those

systems adding disinfection because of

the addition of aeration treatment,

disinfection treatment costs for very

small systems are estimated at an

additional $1.40/kgal and costs for large

systems are estimated at an additional

$0.07/kgal. Aeration production costs

have been adjusted to include costs that

account for the addition of a chemical

stabilizer (orthophosphate) by 25

percent of small systems (those serving

10,000 persons or fewer) and by 15

percent of large systems. In other words,

the production costs shown are

weighted averages that simulate the

installation of aeration without

chemical stabilizers by a fraction of the

systems and with chemical stabilizers

by the remaining fraction. Chemical

stabilizers are used to minimize fouling

from iron and manganese and/or to

reduce corrosivity to the distribution

system. Chemical addition cost

estimates include capital costs for feed

systems and operations and

maintenance costs for the processes

involved. Table VII.A.3 summarizes

total production costs for system size

categorizes for 80 percent radon

removal. Further details on costing

assumptions and breakdown of the unit

treatment costs can be found in the RIA

(USEPA 1999h).

TABLE VIII.A.3.—TOTAL PRODUCTION COST1 OF CONTAMINANT REMOVAL BY BAT FOR 80 PERCENT RADON REMOVAL

(DOLLARS/1,000 GALLONS, LATE 1997 DOLLARS)

Population Served

25–100 100–500 500–1,000 1,000–3,300 3,300–

10,000 >10,000

Aeration2 ............................................................................ 2.06 0.71 0.39 0.22 0.15 0.08–0.10

Aeration + disinfection ....................................................... 3.44 1.09 0.69 0.40 0.22 0.09–0.12

Granular Activated Carbon (GAC) ..................................... 0.34 2.16 2.16 NA NA NA

GAC + disinfection ............................................................. 1.71 2.54 2.46 NA NA NA

POE GAC + UV disinfection .............................................. 16.99 14.03 NA NA NA NA

Notes:

1 Cost ranges are estimated from cost equations found in the radon Technologies and Costs document (EPA 1999h), as used in the radon

HRCCA (64 FR 9559). 2Aeration costs are weighted to include chemical inhibitor costs (Fe/Mn and corrosion control) for 25 percent of small systems and 15 percent

of large systems.

(b) Case Studies of Treatment Unit

Costs. Case studies for aeration and GAC

are reported in detail in the radon

Technologies and Costs document

(USEPA 1999h). Total production costs

for aeration case studies ranged from an

average of $0.82/kgal for systems

serving 25—100 persons (n = 4,

standard deviation = $0.32/kgal, average

population = 58) to $0.19/kgal for

systems serving 100—3,300 persons (n =

11, standard deviation = $0.22/kgal,

average population = 873). Total

production costs for GAC ranged from

$1.50/kgal for systems serving fewer

than 100 persons (n = 2, standard

deviation = $0.48/kgal, average

population = 55) to $0.40/kgal for a

system serving approximately 23,000

persons. Production costs for two POE

GAC installations ranged from $0.21/
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kgal to $0.75/kgal. It should be noted

that these POE GAC costs do not

include the additional monitoring costs

that would apply in a compliance

situation. Annual monitoring costs are

generally negligible compared to annual

treatment costs for centralized treatment

(<2.5 percent for very small systems to

<1 percent for large systems), and may

be significant in the case of POE

treatment (USEPA 1998g). For this

reason, the POE GAC case study

production costs may under-estimate

true POE GAC costs. In general, the case

studies suggest that EPA’s modeled unit

costs may be conservative for small

systems. Since it is true that the radon

case studies are not necessarily a

random sample of all systems that will

be impacted by the future radon rule, it

may be argued that the typical reported

costs may differ significantly from the

typical costs of compliance. However,

the costs of aeration from the radon case

studies overlap nicely with the costs

reported in the VOCs case studies,

which should represent typical costs of

compliance. Given this fact and the

large number of case studies used, EPA

has confidence that the case studies

represent a best estimate of costs of

treatment for compliance purposes. It

should be noted that these reported case

study costs are total costs and include

all pre- and post-treatments added with

the radon treatment process.

(c) Treatment Cost Assumptions and

Methodology. The general assumptions

used to develop the treatment costs

include costs for: chemicals and general

maintenance, labor, capital amortized

over 20 years at a 7 percent interest rate,

equipment housing, associated

engineering and construction, land for

small systems (design flow < 1 mgd per

well), and power and fuel (USEPA

1998h, USEPA 1998g, USEPA 1999h).

Costs were updated to December 1997

dollars using a standard construction

cost index (Engineering News-Record

Construction Cost Index). Process

capital costs for aeration technologies

were calculated using updated cost

equations from the Packed Tower

Column Air Stripping Cost Model

(USEPA 1993e). Process capital costs for

granular activated carbon and total

capital costs for iron and manganese

sequestration/corrosion control, and

disinfection were calculated using

standard EPA models (as described in

USEPA 1998e and USEPA 1999a).

Construction, engineering, land,

permitting, and labor costs were

estimated based upon recommendations

from an expert panel comprised of

practicing water design and costing

engineers from professional consulting

companies, utilities, State and Federal

agencies, and public utility regulatory

commissions (USEPA 1998i). GAC

disposal costs are included in the GACCOST O&M model. All cost estimates

include capital costs for equipment

housing and land for small systems

(design flows < 1.0 MGD). It was

assumed that all treatment installations

would include disinfection. Capital and

operating & maintenance costs for iron

and manganese (Fe/Mn) sequestration

by the addition of zinc orthophosphate

were included for 25 percent of small

systems and 15 percent of large systems.

Pre- and post-treatment assumptions are

explained in more detail later.

(d) ‘‘Decision Tree’’. Compliance costs

were estimated assuming that noncompliant water systems would choose

from a variety of compliance options,

including installing a suitable treatment

train, finding an alternate source of

water, purchasing water from a near-by

water utility, and using best

management practices, like blending or

ventilated storage. The modeled

proportions of systems choosing a

compliance pathway (the ‘‘decision

tree’’) is based on the assumption that

systems will choose the most costeffective alternative, given the fact that

site-specific factors (e.g., a well located

in a suburban residential area) may

force some systems to choose an option

that is more expensive than the least

cost alternative. The modeled

proportions were assumed to vary by

system size and water quality. More

details on these assumptions are found

in the Health Risk Reduction and Cost

Analysis supporting this proposal (64

FR 9559).

(e) Iron and Manganese Assumptions.

Treatment costs assume that 25 percent

of small systems and 15 percent of large

systems installing aeration will need to

add an additional chemical inhibitor

(e.g., orthophosphate, polyphosphates,

silicates, etc.) to minimize the formation

of iron/manganese (Fe/Mn) precipitates

and carbonate scale; to reduce biofouling from the growth of Fe/Mn

oxidizing bacteria (See, e.g., Faust and

Aly 1998); and to reduce water

corrosivity. Although zinc

orthophosphate was assumed to be

universally used, this was done as a

simplifying costing assumption, and

should not interpreted as suggesting that

zinc orthophosphate is the appropriate

inhibitor choice for all circumstances.

Uncertainty analyses were performed in

national cost estimates to simulate a

range of choices of chemical inhibitors

by systems and to simulate a range in

the percentages of systems requiring the

addition of an inhibitor. It is reiterated

that, for the purposes of iron/manganese

control and corrosion control, other

chemical inhibitors may be more

appropriate than zinc orthophosphate

on a case by case basis.

(f) Iron and Manganese Occurrence.

Tables VIII.A.4 and VIII.A.5 show the

estimated co-occurrence of radon with

dissolved iron and manganese in raw

ground water for various radon and Fe/

Mn levels. It can be seen from these

tables (based on the U.S. Geological

Survey’s National Water Information

System database, ‘‘NWIS’’) that the

majority of ground water systems will

be expected to have Fe/Mn source water

levels below the secondary MCLs

(SMCLs) for iron (greater than 85

percent of GW samples have less than

the SMCL of 0.3 mg/L) and manganese

(greater than 75 percent of GW systems

have less than the SMCL of 0.05 mg/L).

Since Fe/Mn precipitation inhibitors are

appropriate for treating combined Fe/

Mn levels up to around 1–2 mg/L (Faust

and Aly 1998, USEPA 1999h), this data

indicates that the vast majority of

ground water systems (greater than 95

percent) will be expected to be in

situations where inhibitors are sufficient

for handling iron and manganese

problems. The cost estimates

conservatively assume that inhibitors

will also be used by systems with source

water below the SMCLs for iron and

manganese. Systems with Fe/Mn levels

above 1–2 mg/L may require oxidation/

filtration or a similar removal

technology. However, it should be noted

that Fe/Mn levels this high may cause

very noticeable nuisance problems,

including ‘‘red water’’, noticeable

turbidity, laundry and sink staining, and

interference with the brewing of tea and

coffee. It is likely that many systems

with source water Fe/Mn levels this

high will have already addressed this

problem.
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TABLE VIII.A.4.— CO-OCCURRENCE OF RADON WITH DISSOLVED IRON IN RAW GROUND WATER1, 2 (4188 SAMPLES)

Radon

(pCi/L)

Dissolved Fe (mg/L) (percent)

ND <0.3 0.3–1.5 1.5–2.5 >2.5 Totals

ND .................................................................................... 0.67 0.36 0.21 0.02 0.31 1.57

<100 ................................................................................. 2.17 1.72 0.53 0.12 0.48 5.02

100–300 ........................................................................... 7.55 10.20 2.67 1.34 1.74 23.50

300–1,000 ........................................................................ 18.89 22.61 3 3.08 0.57 1.31 46.46

1,000–3,000 ..................................................................... 6.42 9.05 0.74 0.10 0.62 16.93

>3,000 .............................................................................. 2.10 3.82 0.31 0.02 0.26 6.51

Totals ........................................................................ 37.80 47.76 7.54 2.17 4.72 100.00

Notes:

1Based on analyses as described in USEPA 1999c.

2The USGS National Water Information System (NWIS) database was used for this analysis.

3Shaded area denotes region where radon level is above MCL and dissolved iron is above 0.3 mg/L, the secondary MCL for iron.

TABLE VIII.A.5.—CO-OCCURRENCE OF RADON WITH DISSOLVED MANGANESE IN RAW GROUND WATER 1, 2 (4189

SAMPLES)

Radon

(pCi/L)

Dissolved Mn (mg/L) (percent)

ND <0.02 0.02–0.05 >.050 Totals

ND ............................................................................................................ 0.69 0.26 0.05 0.57 1.57

<100 ......................................................................................................... 2.67 0.84 0.36 1.15 5.02

100–300 ................................................................................................... 8.00 5.97 2.20 7.33 23.50

300–1,000 ................................................................................................ 21.99 11.84 3.17 3 9.48 46.48

1,000–3,000 ............................................................................................. 6.45 5.90 1.24 3.34 16.93

>3,000 ...................................................................................................... 1.43 3.39 0.53 1.17 6.52

Totals ................................................................................................ 41.23 28.20 7.55 23.04 100.00

Notes: 1 and 2: See Table VIII.A.4. 3 Shaded area denotes region where radon level is above MCL and dissolved manganese is above 0.05 mg/L, the secondary MCL for manganese.

A similar analysis of the National Inorganic and Radionuclides Survey (NIRS) database, which sampled finished

ground water, suggests that greater than 81 percent of GW systems sampled have dissolved Fe/Mn levels less than

0.3 mg/L and greater than 97 percent of systems sampled have levels less than 1.5 mg/L (USEPA 1999h). Table VIII.A.6

compares combined Fe/Mn levels predicted by the NIRS database to occur in finished ground water with levels predicted

by NWIS to occur in raw ground water. This table is consistent with expectations that the vast majority of ground

water systems will have combined Fe/Mn levels below 1–2 mg/L and that a significant fraction of ground water systems

with Fe/Mn levels above the SMCL are already taking measures to reduce Fe/Mn levels.

TABLE VIII.A.6.—CO-OCCURRENCE OF RADON WITH DISSOLVED COMBINED IRON AND MANGANESE IN RAW AND FINISHED

GROUND WATER

Ground water type

Percent of samples with

dissolved combined Fe

and Mn (mg/L) (percent) Data sources

<0.3 <1.5

Finished Ground Water ..................................................................................................... >81, >93 >97 >99 NIRS,1 AWWA Water:/

Stats 2

Raw Ground Water ........................................................................................................... >85, >71 >95 >88 NWIS,3 AWWA Water:/Stats

Notes:

1 ‘‘National Inorganics and Radionuclides Survey’’: See USEPA 1999c for references.

2American Water Works Association, ‘‘Water:/Stats, 1996 Survey: Water Quality’’.

3 USGS, National Water Information System.

An analysis of the American Water

Works Association (AWWA) ‘‘Water:/

Stats’’ database corroborates these

conclusions: average Fe/Mn levels in

finished water from 442 ground water

systems showed that greater than 93

percent of the systems had combined

Fe/Mn levels less than 0.3 mg/L and

greater than 99 percent of systems had

combined Fe/Mn levels less than 1.5

mg/L (AWWA 1997); average Fe/Mn

levels in raw ground water from 433

systems showed that greater than 71

percent of systems had combined Fe/Mn

levels less than 0.3 mg/L and greater

than 88 percent of systems had Fe/Mn

levels less than 1.5 mg/L. While this

analysis does support the conclusions

from NIRS and NWIS, it should be

noted that the AWWA ‘‘Water:/Stats

Survey’’ is skewed towards large ground

water systems: only 3.4 percent of the

systems surveyed serve fewer than

10,000 persons, whereas at the national
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level, greater than 95 percent of ground

water systems serve fewer than 10,000

persons. In comparison, NIRS was

designed to be nationally representative

of contaminant occurrence in CWSs,

while NWIS is a ‘‘data bank’’ in which

the U.S. Geological Survey stores water

contaminant data from its various

studies. While the data in NWIS was not

collected as part of a designed national

survey (and hence can not be claimed to

be necessarily nationally

representative), it is arguably nationally

representative based on its large sample

size and its wide distribution of sample

collection locations (USEPA 1999c).

(g) Disinfection Assumptions. It was

assumed that all systems adding

treatment would include disinfection.

Since a significant fraction of ground

water systems already disinfect, the

percentage of systems that would have

to add disinfection was estimated from

a ‘‘disinfection-in-place baseline’’, as

described in the Radon Health Risk

Reduction and Cost Analysis published

on February 26, 1999 (64 FR 9559). It

should be noted that this baseline is

nationally representative. Some States

will, of course, have higher proportions

of ground water systems with

disinfection-in-place (e.g., those States

that require that ground water systems

disinfect) and some will have lower

proportions. Since the cost estimates

being calculated are at the national

level, EPA believes that this assumption

is valid since this will over-estimate

costs for systems in some States and

under-estimate costs for systems in

other States, with the respective cost

errors tending to cancel at the national

level. As a simplifying cost assumption,

chlorination was assumed for all

systems adding disinfection. The actual

choice of disinfection technology

should, of course, be made on a case by

case basis. The fact that many systems

will choose disinfection systems other

than chlorination and that some systems

will not add disinfection at all is

captured in the uncertainty analysis,

described later in this section.

(h) Comparison of Modeled Costs with

Real Costs from Case Studies. Figure

VIII.A.1 compares modeled total capital

costs against case studies of actual

aeration treatment installations for

radon and VOCs found in the literature

and gathered by EPA. It should be noted

that these case studies include all preand post-treatments capital costs and

costs for land, housing structures,

permits, and all other capital added

with the aeration process. If EPA’s

assumptions regarding pre- and posttreatments were seriously flawed, this

comparison would demonstrate the fact.

As can be seen, EPA’s models fit the

data fairly well and, in fact, Figure

VIII.A.2 shows that the ‘‘typical cost

model’’ rather closely approximates a

power fit through the capital cost data

for the larger systems and significantly

over-estimates capital costs for small

systems.

The ‘‘PTA Cost Model’’ represents

EPA’s best estimate of the costs of

constructing and operating a PTA

system under the associated design

assumptions (steel shell, below-ground

concrete clearwell, structure, etc.). This

design was intended to be fairly typical

of those systems serving more than 500

persons and up to 1,000,000 persons.

The ‘‘High Side PTA Cost Model’’

represents EPA’s best estimate of the

costs of constructing and operating a

PTA system under the same basic

treatment design, but including

significantly higher land, structure, and

permitting costs. This model was

intended to be fairly typical of systems

that are ‘‘land-locked’’ in suburban or

urban areas where land costs, building

codes, and permitting demands may be

much higher than for typical situations.

The ‘‘Low Side PTA Cost Model’’

represents EPA’s best estimate of the

costs of constructing and operating a

PTA system using designs more typical

of very small systems, including

package plant installations. This model

is described in the Radon Technologies

and Costs Document (USEPA 1999h). As

can be seen in Figure VIII.A.1, the PTA

Cost and High Side PTA Cost models

are representative of the systems with

design flows greater than 0.1 MGD. All

of these models tend to over-estimate

costs for those systems with smaller

design flows.

The relative percentages of noncompliant systems modeled by the

low-, typical-, and high-side costs are

shown in the ‘‘decision tree’’ in Table

7–3 of the Regulatory Impact

Assessment supporting this proposal.

As part of the uncertainty analysis

(described later in this section), these

decision tree percentages were varied

significantly. The results and

assumptions are presented in detail in

Section 10.8.3 of the Regulatory Impact

Assessment. Based on a sensitivity

analysis of the relative impacts of all the

cost elements studied, the variance in

the decision tree percentage values had

much less of an impact on national costs

compared to the variance in the

treatment unit costs ($/kgal).

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Figure VIII.A.2 compares the EPA

aeration capital cost models against best

fits to aeration capital cost case studies

from the Radon Technologies and Costs

Document (which includes aeration

installations for VOCs) and to capital

costs for radon case studies as reported

by American Water Works Association

Research Foundation (AWWARF

1998b). In general, EPA’s unit cost

estimates are supported by the case

studies cited previously and by the

findings reported by the AWWARF

(AWWARF 1998b).

Figure VIII.A.3 shows that EPA’s

modeled operations and maintenance

(O&M) costs are representative of the

case study cost data. It should be noted

that EPA is modeling incremental O&M

aeration costs (additional O&M costs

due to the addition of radon treatment)

and that many of the radon case studies

and all of the VOCs case studies report

total O&M costs, which include O&M

costs not related to the removal of

radon. For this reason, the case study

O&M costs would be expected to be

considerably higher than the modeled

costs, especially for the larger systems

(which tend to have other processes in

place that require substantial O&M

costs). For example, most of the case

studies using disinfection already had

disinfection in place before adding

aeration for radon. Since it is very

difficult to separate the individual

components of O&M costs without

detailed site-specific information, these

disinfection O&M costs are included in

the O&M costs shown even though they

are not related to treatment added for

radon. As described previously, EPA

did model O&M costs for disinfection

and sequestration for iron and

manganese and did include these in its

national cost estimates. Figure VIII.A.3

compares modeled O&M costs for

aeration with and without disinfection.

Modeled O&M costs for iron/manganese

stabilization and corrosion control are

included through a weighting procedure

that simulates 25 percent of small

systems and 15 percent of large systems

adding a chemical inhibitor. EPA

solicits public comment and data on

treatment costs and performance for the

removal of radon from drinking water.

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Figures VIII.A.4 and VIII.A.5 compare

the modeled capital costs and O&M

costs for GAC against actual costs

reported in case studies (USEPA 1999a,

AWWARF 1998b). As can be readily

seen, EPA’s modeled costs are

significantly higher than the actual

costs, especially so for very small flows.

To account for this discrepancy, EPA

used the best fit through the case study

data to generate a calibrated GAC model

for capital and O&M costs. EPA

calculated GAC treatment costs based

on this model and did an uncertainty

analysis on GAC costs assuming that

while the modeled costs were typical,

they could be as high as the GAC–COST

predictions. This procedure is described

in more detail in the radon HRRCA.

EPA also estimated point-of-entry

GAC (POE–GAC) costs for very small

systems. While capital and standard

maintenance costs may be affordable

($100–$350 per household per year),

monitoring costs can make POE–GAC

much more expensive. EPA estimates

(USEPA 1998g) that monitoring costs

alone can be as much as $140 per

household per year. A ‘‘high end’’

estimate for POE–GAC is $1,000 per

household per year. If more costeffective monitoring and maintenance

program schemes are devised, these

costs may be considerably lower.

In general, treatment costs may vary

significantly depending on local

circumstances. For example, costs of

treatment will be less than shown if

contaminant concentration levels

encountered in the raw water are lower

than those used for the calculations or

if an existing clearwell can be retrofitted

for aeration. However, costs of treatment

will be higher if oxidation/filtration pretreatment is required for iron and

manganese removal or if water must be

piped from the well-head to an off-site

area for treatment.

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(i) Uncertainty Analysis for Treatment

Costs. To estimate the uncertainty in

national treatment costs, EPA estimated

credible ranges and distributions of

values for the most important factors

(inputs) affecting costs. Distributions of

selected inputs were then used in a

Monte Carlo analysis to explore the

uncertainty in national costs. The cost

factors that were analyzed include:

• Numbers of systems in the various

size categories;

• The distribution of the numbers of

sources (wells) per system in each size

category;

• Distributions of populations served

in each size category;

• Annual household water

consumption;

• Proportions of systems and wells

exceeding radon limits; and

• Unit costs of radon treatment

technologies (aeration and GAC).

Each of these inputs was modeled

using probability distributions that

reflect the spread in the available data.

In some cases, (distributions of

populations served, daily household

water consumption, unit costs)

variability was estimable from SDWIS,

the CWSS, or other sources. In the case

of the numbers of systems of different

sizes, the estimated variability was

greatest for the smallest systems, less for

the moderate size systems, and the

numbers of the largest systems (serving

greater than 100,000 customers) was

assumed to be known with certainty.

The variation in the proportions of

systems and sources above radon limits

was estimated based on EPA’s recent

analysis (USEPA 1999l) of inter- and

intra-system radon variability in radon

levels.

In addition to these inputs, the

estimated percentages of systems

choosing particular treatment

technologies (the ‘‘decision tree’’) were

allowed to vary as well. Three decision

tree matrices were used, corresponding

to a central tendency estimate of the

proportions of systems choosing specific

mitigation technologies, and to lowerand higher-cost distributions of

technology selection. When the

simulation was run, the central

tendency matrix was selected in 80

percent of the iterations, and the lowand high-cost decision matrices were

selected in ten percent of the iterations

each.

The variability in the estimated

mitigation costs was examined using a

conservative test case in which all

systems above an MCL of 300 pCi/L

were assumed to mitigate to comply

with the MCL. The results of the

analysis are described in detail in the

radon Health Risk Reduction and Cost

Analysis. In general, the distribution of

cost estimates, even with all the

variables included in the Monte Carlo

analysis, is much narrower than the

corresponding distribution of risk and

benefit results. For this hypothetical

scenario, the fifth percentile cost

estimate is $455 million per year, while

the 95th percentile estimate is $599

million per year (only 32 percent

higher). The compactness in spread in

national costs relative to the spread in

national benefits is primarily due to the

fact that the variability in the individual

cost model inputs is low relative to the

variability in some of the inputs (e.g.,

individual risk) to the benefits model.

(j) Potential Interactions Between the

Radon Rule and Upcoming and Existing

Rules Affecting Ground Water Systems:

Aeration and GAC are BAT for more

than 25 and 50 currently regulated

contaminants, respectively. Both

technologies have been welldemonstrated and the secondary effects

of each technology are well understood

(See, e.g., Cornwell 1990, Umphres and

Van Wagner 1986, AWWA 1990). These

technologies are also used to remove

other contaminants from drinking water,

including taste and odor causing

compounds. The Community Water

System Survey (USEPA 1997a) indicates

that 2 to 5 percent of ground water

systems serving fewer than 500 persons

currently have aeration treatment in

place. Of systems serving more than 500

persons, 10–25 percent of these systems

have aeration treatment at one or more

entry points.

In the case of aeration, these

secondary effects include carbon

dioxide release (pH increase), oxygen

uptake, and potential bacterial density

increases, all of which potentially

impact other existing and future

drinking water regulations that pertain

to ground water. In the case of GAC

treatment, potential bacterial density

increases are of concern. These potential

interactions are described in a following

section. (Concerns that are specific to

radon removal and secondary effects

due to other contaminants, e.g., radium

and uranium, are discussed in part 3 of

this Section.)

(k) Ground Water Rule: Since the

treatment techniques applicable to the

removal of radon, i.e., aeration, GAC,

and/or ventilated storage, may result in

increases in microbial activity (NAS

1999b, Spencer et al. 1999), it is

important that water systems determine

whether post-treatment disinfection is

necessary. The ‘‘Ten States Standards’’

(GLUMRB 1997) suggest that

disinfection should follow ground water

exposure to the atmosphere (e.g.,

aeration or atmospheric storage). The

Ten State Standards also suggest that

systems using GAC treatment

implement ‘‘provisions for a free

chlorine residual and adequate contact

time in the water following the [GAC]

filters and prior to distribution.’’ While

EPA is not requiring that disinfection be

used in conjunction with any treatment

for radon, it is including costs for

disinfection with treatment in

accordance with good engineering

practice. Cost assumptions for

disinfection, including clearwell sizing

for 5–10 minutes of contact time, are

consistent with 4-log viral inactivation

for ground water, which is expected to

be consistent with requirements in the

upcoming Ground Water Rule.

It should be noted that air is not a

significant pathogen vector and thus

aeration does not necessarily increase

pathogenic risk for ground water users.

However, bacterial activity can increase

upon aeration and/or treatment with

GAC. In the case of aeration treatment,

bacteria that oxidize iron and/or sulfide

may proliferate because of the oxygen

increase; in the case of GAC treatment,

bacteria may proliferate since the GAC

surface tends to accumulate organic

matter and nutrients that support the

bacteria. In either case, heterotrophic

plate count limits may become high

enough to be of concern and for this

reason disinfection may be necessary

(USEPA 1999h, NAS 1999b).

(l) Disinfectants and Disinfection

Byproducts (D/DBP) Rule: Commonly

used disinfection practices for ground

water systems include chlorination and,

especially for small systems with

limited distribution systems, ultraviolet

(UV) radiation. Disinfection is used by

many ground water systems because it

decreases microbial risks from microbial

contamination of ground water (NAS

1999b). However, there is a trade-off

between a reduction in microbial risks

and the risks introduced from

disinfection by-products. Various

disinfectant by-products (DBPs) can be

formed depending on the disinfectant

used, the disinfectant concentration and

contact time, water temperature, the

levels of DBP pre-cursors like natural

organic materials and bromide, etc. For

example, chlorination by-products like

trihalomethanes can result from the

interaction between chlorine chemical

species and naturally occurring organic

materials (NOM) and bromate can result

from the ozonation of waters with

sufficiently high levels of naturally

occurring bromide ion.

Ground water systems tend to have

significantly lower trihalomethane

(THM) organic precursors than surface

waters, although this is not always the

case. Total organic carbon (TOC) is often
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59287

used as a surrogate for formation of one

important class of DBPs, total

trihalomethanes (THM), since the THM

formation potential of chlorinated

waters correlates with TOC. As reported

in the proposed Disinfectants and

Disinfection Byproducts Rule (July 29,

1994: 59 FR 38668), a survey of surface

waters showed TOC levels at the 25th,

50th, and 75th percentiles of 2.6, 4.0,

and 6.0 mg/L, respectively; ground

waters showed TOC levels at the same

percentiles of ‘‘non-detect’’, 0.8, and 1.9

mg/L, respectively. Nationally, typical

ground waters have low TOC levels.

However, some areas of the U.S., e.g.,

the Southeastern U.S. (EPA Region 4),

have some aquifers with high TOC

levels.

One approach for the minimization of

DBP formation in drinking water is to

employ a disinfectant other than

chlorine. Primary disinfection with

chloramination, ozonation, or UV

radiation are examples. However, other

considerations may apply. For example,

ozonation of ground water with

sufficiently high bromide levels may

result in significant levels of the DBP

bromate. If a residual is required, it may

be necessary to add secondary

chlorination to maintain a residual in

the distribution system. Other strategies

include reducing the precursor

concentration prior to chlorination,

removal of THMs after their formation,

and the installation of a second

chlorination point in the distribution

system. This last approach allows much

lower chlorination levels to be used for

primary chlorination, which greatly

reduces THM formation.

While these strategies may be

employed to minimize the formation of

DBPs and, thereby reducing potential

DBP risks and avoiding MCL violations

for the DBP rule, there are other reasons

to expect minimal interactions between

the radon rule and the D/DBP rule.

Namely, EPA expects that the radon rule

will not result in a large percentage of

systems adding disinfection because of

the need to treat for radon. Since the

primary regulatory option for small

ground water systems is the MCL/MMM

option (MCL = 4000 pCi/L) and less

than one percent (1%) of small systems

have radon levels that high, EPA does

not expect many small systems to add

treatment for radon in response to the

radon rule, resulting in a very small

percentage of small systems adding

disinfection. Roughly half of all small

systems already half disinfection in

place already, further suggesting

minimal small system impact from the

radon rule. While EPA also expects that

many large systems will also adopt the

MCL/MMM option, EPA estimates that

95–97 percent of large ground water

systems are already disinfecting, and

thus would not have to add disinfection

if treating for radon. For the expected

small minority of systems that do add

chlorination disinfection with radon

treatment, the trade-off between a

reduction in risks from radon exposure

to an increase in risk from disinfection

by-products will need to be carefully

considered by the system installing

treatment and strategies to minimize

DBP formation should be implemented

(NRC 1997, NAS 1999b, Spencer et al.

1999).

(m) Lead and Copper Rule: For

several reasons, it is expected that few

systems already in compliance with the

Lead and Copper Rule will experience

direct cost impacts because of the Radon

Rule. Systems serving fewer than 50,000

persons do not have to modify corrosion

control practices if the lead and/or

copper contaminant trigger levels are

not exceeded. For the reasons explained

next, aeration is not expected to result

in increased lead and copper levels in

the vast majority of cases. While larger

systems will have to include radon

treatment into their over-all ‘‘optimal

corrosion control’’ plans as they are

updated, aeration tends to reduce or

maintain corrosivity levels and should

not result in measures beyond those

included in the national costs for the

proposed radon rule.

Aeration of ground water for radon

treatment tends to raise the pH of water

(Kinner et al. 1990, as cited by NAS

1999b, Spencer et al. 1999), since it

tends to remove dissolved carbon

dioxide, which forms carbonic acid

when dissolved in water. In a study of

VOCs removal by aeration, the

American Water Works Association

(AWWA 1990) reported that the net

effect of aeration was ‘‘no increase in

corrosivity’’: The reduction in carbon

dioxide levels resulted in higher pH and

in increased stability of carbonate

minerals that serve to protect

distribution systems, negating the

corrosive effects of increased oxygen

levels. The NAS concludes (NAS 1999b

and references cited within Spencer et

al. 1999) that studies suggest that

corrosivity tends to decrease with

aeration, but that a minority of systems

that aerate may have to add a corrosion

inhibitor to stabilize the impacts of the

increased oxygen levels. As described

previously, EPA has assumed in its

national costs that, of the systems that

install aeration, 25 percent of small

systems and 15 percent of large systems

will add chemical inhibitors for the dual

purposes of corrosion control and the

control of iron and manganese.

(n) Arsenic Rule: It is expected that

there will be no significant negative

relationships between compliance

measures for the Arsenic and Radon

Rules. In fact, one of the few expected

impacts is beneficial: aeration plus

disinfection may serve to pre-oxidize

As(III) to the more readily removable

As(V) form. However, the benefits

estimated in this notice do not reflect

this potential benefit.

3. Descriptions of Technologies and

Issues

(a) Aeration. Aeration techniques for

removal of radon from drinking water

include active processes such as

diffused bubble aeration (DBA), packed

tower aeration (PTA), simple spray

aeration, slat tray aeration, and free fall

aeration, with or without spray aerators.

Passive aeration processes such as freestanding, open air storage of water for

reduction of radon may be effective for

systems requiring lower removal

efficiencies. Additional removal of

radon via radioactive decay (into the

daughter products of radon) may also

occur in storage tanks and in pipelines

which distribute drinking water,

reducing radon by approximately 10 to

30 percent, within 8 to 30 hour

detention periods. Although all of these

aeration processes may be effective,

depending on site specific conditions,

only active aeration processes are

considered BAT. Site specific

considerations that may influence an

individual water system’s choice of

treatment include source water quality

(including concentrations of radon and

other contaminants removed or

otherwise affected by aeration),

institutional or labor constraints,

wellhead location, seasonal climate

(e.g., temperature), site-specific design

factors, and local preferences. Identical

treatment designs may achieve different

radon removal efficiencies at individual

water systems, depending upon these

factors. A design for a technology may

be altered to increase the radon removal

efficiency, e.g., an increase in the

technology’s air:water ratio (the

respective flows of air and water being

mixed) may increase the radon removal

efficiency to account for local

conditions that depress the radon

removal efficiency. In some cases, the

removal efficiency requirement may be

high enough that only high performance

aeration technologies (e.g., packed tower

aeration) will achieve the desired

removals.

High performance aeration

technologies, e.g., packed tower aeration

(PTA) and package plant aerators with

high air:water ratios like shallow tray

aeration (STA) or multi-stage bubble
59288 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

aeration (MSBA), provide the most

efficient transfer of radon from water to

air, with the ability to remove greater

than 99 percent of radon from water. A

supply which requires a smaller

reduction of radon, e.g., 50 percent,

could opt to install one of these

technologies and treat 50 percent of its

source water and subsequently blend

the treated with raw water, or it may

design a shorter packed tower to achieve

compliance with the MCL, both of

which are significantly cheaper than

treating the entire flow to 99 percent

radon removal. Other advantages of high

performance aeration include: removal

of hydrogen sulfide, carbon dioxide, and

VOCs, and oxidation of iron and

manganese. Full-scale PTA, STA, and

MSBA installations have been

constructed for the removal of radon for

very small up to medium sized-systems

(AWWARF 1998b, USEPA 1999a). In

addition to these case studies, full-scale

aeration facilities for VOCs removal for

medium to large-sized systems have

been reported in the literature (AWWA

1990). Since radon is more easily air

stripped than most volatile organic

compounds, and high performance

aeration technologies have been shown

to be efficient forms of aeration for VOC

removal (Kavanaugh and Trussell 1989,

Dyksen et al. 1995), these technologies

are appropriate as BAT for radon.

Treatment issues regarding aeration

have been discussed in the literature

(e.g., Dihm and Carr 1988, Kinner et al.

1990b, Dell’Orco et al. 1998, AWWARF

1998b) and by EPA (USEPA 1999d).

These issues include the potential for

bacteria fouling (e.g., iron/manganese/

sulfide oxidizing bacteria), iron and

manganese chemical precipitation and

scaling, and corrosivity changes.

Bacteria fouling and Fe/Mn scaling may

clog or otherwise impede operations at

an aeration facility, requiring

preventative maintenance and/or

periodic cleaning. Regarding corrosivity,

the aeration process tends to reduce

carbon dioxide levels (and raise pH,

which tends to decrease corrosivity) and

introduce oxygen (which tends to

increase corrosivity). Whether or not

corrosivity increases or decreases

depends on site specific factors. In

general, the degree to which these

treatment issues may occur depends on

the source water quality, ambient water

and air temperatures, pre- and posttreatments added or in place, the type

of aeration used, and other factors. To

account for the cost impacts of dealing

with Fe/Mn/carbonate scaling, EPA has

included the capital and operation and

maintenance costs of pre-treatment with

a scalant stabilizer (which also may

serve as a corrosion inhibitor,

depending upon the type of corrosivity).

Pre-/Post-treatment with a disinfectant

to control biological fouling and to

provide four-log viral deactivation

(assuming a five minute contact time at

1.0–1.5 mg/L chlorine) has also been

assumed in cost estimates. EPA

assumed that those groundwater

systems without disinfection already in

place will add disinfection when

aerating.

The PTA process involves the use of

packing materials to create pore spaces

that greatly increase the air:water

contact time for a given flow of air into

water. In counter-current PTA, the water

is pumped to the top of the tower, then

distributed through the tower with

spray nozzles or distribution trays. The

water flows downward against a current

of air, which is blown from the bottom

of the tower by forced or induced draft.

The air space at the top of the tower is

continually refreshed with ventilators.

This design results in continuous and

thorough contact of the water with

ambient air. The factors that determine

the radon removal efficiency are the

air:water ratio (the ratio of air blown

into the bottom of the tower and the

water pumped into the top of the tower),

the type and number of packing

material, the internal tower dimensions,

the water loading rate, the radon level

in the influent and in the ambient air,

and the water and air temperatures. A

typical packed tower aeration

installation consists of: (1) the tower: a

metal (stainless steel or aluminum),

fiber-glass reinforced plastic, or concrete

tower with internals consisting of

packing material with supports and

distributors, (2) a blower or blowers, (3)

effluent storage, which is generally

provided as a concrete clearwell

(airwell) below the tower; very small

systems may use metal or plastic storage

tanks, and (4) effluent pumping.

Pumping into the tower is performed

either through modification or

replacement of the original well pump.

Commercially available high

performance package plant aerators

(USEPA 1999a, AWWARF 1998b)

include multi-stage bubble aerators

(MSBA), shallow tray aerators (STA),

and other high air:water ratio designs.

MSBA units typically consist of shallow

(typically less than 1.5 feet deep) highdensity polyethylene tanks partitioned

into multiple stages with stainless steel

or plastic dividers. Each stage is

provided with an aerator, each of which

is connected to the air supply manifold.

STA units typically consist of one to six

stacked tray modules (each 18 to 30

inches deep). Water is pumped through

each tray as air is blown through

diffusers at the bottom of the tray,

creating turbulent mixing of the air and

water. These package plant aerators

have several distinct advantages: they

are low-profile and compact (small

footprint), are considered

straightforward to install, and are

relatively easy to maintain.

Other varieties of active aeration

include diffused bubble aeration, which

involves the bubbling of air into the

water basin (of varying depth and

design) via a set of air bubble diffusors.

Forms vary from designs with shallow

depth tanks containing thousands of

diffusers to ‘‘low technology’’ designs

involving bubbling air into a storage

tank via a perforated hose connected to

a blower. Some forms of diffused bubble

aeration can remove up to 99.9 percent

of radon from drinking water; simpler

varieties can remove from 80 to > 90

percent of radon. One of the main

advantages of diffused bubble aeration

is its potential for making use of existing

basins for the aeration process, which

substantially reduces construction costs.

Even if the aeration basin must be newly

constructed, this process can be more

cost effective than PTA for small

systems. The disadvantages of diffused

aeration include the requirement for

increased contact time, the

impracticality of large air-to-water ratios

because of air pressure drops, and

overall less efficient mass transfer of

radon from water. The level of contact

between air and water achievable in a

packed tower aerator is difficult to

obtain in a simple diffused air system

(i.e., forms like MSBA can achieve

comparable contacts).

The Radon Technology and Cost

document (USEPA 1999h) summarizes

treatability studies for four diffused

bubble aeration installations. One of the

case studies involves a full-scale

diffused aeration plant in Belstone,

England, which provided a long-term

radon removal efficiency of 97 percent.

This plant (design flow of 2.5 mgd) was

designed with an air:water ratio, using

2,800 air diffusers, each designed to

supply a maximum of 0.8 cubic feet per

minute, and a 24-minute retention time.

In a field test of a diffused bubble

aeration system, Kinner et al. (1990)

report that removals of 90 to 99 percent

were achieved at air-to-water ratios of 5

and 15, respectively.

Spray aerators direct water upward,

vertically, or at an angle, dispersing the

water into small droplets, which

provide a large air:water interfacial area

for radon volatilization. In single pass

mode, depending upon the air:water

ratio, removal efficiencies of >50 to >85

percent can be achieved. In multiple

pass mode, 99 percent removals can be
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59289

achieved. Most of the advantages cited

previously for diffused aeration also

apply to spray aeration. Disadvantages

include the need for a large operating

area and operating problems during cold

weather months when the temperature

is below the freezing point. Costs

associated with this option (for all sizes

of water treatment plants) have not been

developed by EPA, but case studies

(USEPA 1999a, AWWARF 1998b)

indicate that it is cost-competitive with

other small systems aeration

technologies.

EPA has evaluated other, less

technology-intensive (‘‘lowtechnology’’), options which may be

suitable for small water systems, and

which may cost less than the options

described previously to install and

operate (Kinner et al. 1990b, USEPA

1999a, AWWARF 1998b). These options

include: atmospheric storage, free fall

with nozzle-type aerator, bubble

aerators, blending, and slat tray aerators.

Limited data concerning these lowtechnology alternatives are reviewed in

USEPA 1999a and AWWARF 1998b.

Case studies show that atmospheric

storage with a detention time of nine

hours resulted in removals of 7–13

percent and a detention time of 30 hours

in removals of around 35 percent. Dixon

and Lee (1987) report that blending 6.34

MG of well water with a radon level of

1079 pCi/L with 18.34 MG of surface

water resulted in effluent water with

226 pCi/L. Other storage case studies

(detention times ranging from 8 to 23

hours) show that free-fall into a tank,

free-fall with simple bubble aeration,

simple spray aeration with free-fall, and

simple bubble aeration remove 50–70

percent, 85–95 percent, 60–70 percent,

and 80–95 percent of radon,

respectively. More detail on an example

will illustrate the simplicity of the

treatment involved: the case study for

‘‘free-fall with simple bubble aeration’’

cited previously involved the

introduction of water through two feet

of free fall into a tank equipped with

garden hose (punctured) bubble

aerators, where the air was supplied by

a laboratory air pump. Kinner et al.

(1990b) concluded that very effective

radon reduction can be achieved by

simple aeration technologies that may

be easily applied in small communities.

(i) Evaluation of Radon Off-Gas

Emissions Risks. Since this notice

contains a proposal to reduce radon

concentrations in drinking water by

setting an MCL, and the EPA is

proposing aeration as BAT for meeting

the MCL, the Agency undertook an

evaluation of risks associated with

potential air emissions of radon from

water treatment facilities due to aeration

of drinking water. In the first evaluation

(USEPA 1988a, 1993a), EPA used radon

data from 20 drinking water systems in

the U.S. which, according to the

Nationwide Radon Survey (1985),

contained the highest levels of radon in

drinking water and affected the largest

populations and/or drinking water

communities. EPA estimated the

potential annual emissions (in pCi

radon/yr) from these facilities, assuming

100 percent radon removal.

These radon emissions estimates were

used as inputs to the AIRDOS-EPA

model, which is a dispersion model that

can be used to estimate the

concentration of radon at a point some

distance from the point source (e.g., a

packed tower vent). This model is the

predecessor to the newer CAP–88–PC

model, which combined AIRDOS with

the DARTAB model, which estimates

the total lifetime risk to individuals and

the total health impact for populations.

The underlying physical models in

CAP–88 are essentially the same as

those underlying AIRDOS and DARTAB

(USEPA 1992c). In fact, the main

differences between CAP–88–PC model

and its predecessors is that CAP–88–PC

is intended for wide-spread use in a

personal computer environment (the

CAP–88–PC model and its supporting

documentation can be downloaded from

the EPA homepage, http://

www.epa.gov/rpdweb00/assessment/

cap88.html). EPA has made

comparisons between the AIRDOS-EPA

dispersion model results and actual

annual-average ground-level

concentrations and found very good

agreement. EPA has studied the validity

of AIRDOS-EPA and concluded that its

predictions are within a factor of two

within actual average ground-level

concentrations, the results of which are

as good as any existing comparable

model (USEPA 1992c).

Estimates of ground-level radon

exposure were made for the following

parameters: air dispersion of radioactive

emissions, including radon and progeny

isotopes of radon decay; concentrations

in the air and on the ground; amounts

of radionuclides taken into the body via

inhalation of air and ingestion of meat,

milk, and fresh vegetables, dose rates to

organs and estimates of fatal cancers to

exposed persons within a 50 kilometer

radius of the water treatment facilities.

Estimates of individual risk and

numbers of annual cancer cases were

completed for each of the 20 water

systems, as well as a crude estimate of

U.S. risks (total national risks) based on

a projection of results obtained for the

20 water systems. These estimates were

based on exposure analyses on a limited

number of model plants, located in

urban, suburban and rural settings,

which were scaled to evaluate a number

of facilities. (A similar approach has

been used by the Agency in assessing

risks associated with dispersion of coal

and oil combustion products.) The risk

assessment results for the 20 systems

indicate the following: a highest

maximum lifetime risk of 2 × 10¥5 for

individuals within 50 km of one of these

systems, with a maximum incidence at

the same location of 0.003 cancer cases

per year; an estimate of annual cancer

cases for all 20 systems of 0.0038 per

year; and a crude U.S. estimate of 0.09

fatal cancer cases/year due to air

emissions if all drinking water supplies

are treated by aeration to meet an MCL

of 300 pCi/L. Two other cases were

evaluated: (1) Assuming that small

drinking water systems are treated by

aeration to meet the MCL/MMM option

of 4000 pCi/L and large systems are

treated to meet the MCL of 300 pCi/L,

the best estimate of total national fatal

cancer cases per year due to radon offgas emissions is 0.04 cases/year, and (2)

Assuming that all systems treat by

aeration to meet the (A)MCL/MMM

option of 4000 pCi/L , the best estimate

is 0.01 cases/year. These results of the

risk assessment for potential radon

emissions from drinking water facilities

are summarized in Table VIII.A.7. For

all MCL options shown, the maximum

lifetime individual risks from radon offgas are much smaller (100 to 70,000

times smaller) than the average lifetime

individual risks from the untreated

water. Regarding national population

risks (fatal cancer cases per year), the

estimated population risk from radon

off-gas is 850 to 17,000 times smaller

than the estimated population risk from

the untreated water.
59290 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

TABLE VIII.A.7.—ESTIMATES OF RISKS AT 20 SITES DUE TO POTENTIAL RADON EMISSIONS FROM AERATION UNITS AND

CRUDE PROJECTION OF TOTAL U.S. RISK 1

Modeling scenario

Concentration

in water

(pCi/L)

Emissions

from facility

(Ci Rn/Yr)

Maximum

lifetime individual risk 2

Population

risk 2

(fatal cancer

cases per

year)

20 Facilities Modeled:

1 ..................................................................................................................... 1,839 2.79 3 × 10¥7 7 × 10¥5

2 ..................................................................................................................... 5,003 6.22 6 × 10¥7 2 × 10¥4

3 ..................................................................................................................... 2,175 2.85 3 × 10¥7 9 × 10¥5

4 ..................................................................................................................... 1,890 20.89 6 × 10¥6 1 × 10¥4

5 ..................................................................................................................... 1,310 1.81 5 × 10¥7 9 × 10¥7

6 ..................................................................................................................... 1,329 91.80 9 × 10¥6 1 × 10¥3

7 ..................................................................................................................... 4,085 2.26 2 × 10¥7 3 × 10¥5

8 ..................................................................................................................... 10,640 1.18 1 × 10¥7 1 × 10¥5

9 ..................................................................................................................... 3,083 0.55 5 × 10¥8 7 × 10¥6

10 ................................................................................................................... 3,270 9.04 2 × 10¥5 1 × 10¥3

11 ................................................................................................................... 2,565 3.54 7 × 10¥6 6 × 10¥4

12 ................................................................................................................... 4,092 13.75 2 × 10¥7 3 × 10¥5

13 ................................................................................................................... 16,135 2.23 2 × 10¥7 3 × 10¥5

14 ................................................................................................................... 3,882 0.27 8 × 10¥8 5 × 10¥6

15 ................................................................................................................... 1,244 1.03 3 × 10¥7 2 × 10¥5

16 ................................................................................................................... 2,437 1.35 4 × 10¥7 5 × 10¥7

17 ................................................................................................................... 996 8.94 9 × 10¥7 2 × 10¥4

18 ................................................................................................................... 7,890 0.87 3 × 10¥7 6 × 10¥6

19 ................................................................................................................... 9,195 1.02 3 × 10¥7 1 × 10¥5

20 ................................................................................................................... 7,500 1.04 3 × 10¥7 6 × 10¥6

Totals for All 20 Facilities ..................................................................................... 161 0.004

Totals Assuming All U.S. Community Water Systems Treat to 300 pCi/L 3, i.e.,

All Systems Meet MCL of 300 pCi/L.

3700 0.09

Totals Assuming All Small U.S. Drinking Water Facilities Treat to 4000 pCi/L 3

and All Large U.S. Drinking Water Treat to 300 pCi/L, i.e., All Small Systems

Meet MCL of 4000 pCi/L and All Large Systems: meet MCL of 300 pCi/L.

1600 0.04

Totals Assuming All U.S. Drinking Water Facilities Treat to 4000 pCi/L 3, i.e.,

All Systems meet MCL of 4000 pCi/L.

240 0.01

Notes:

1Estimates of Risk Assessment Using AIRDOS–EPA to estimate radon exposure. The total U.S. risk is based on the very conservative projection that all CWSs will treat to 200 pCi/L, USEPA 1993b. 2 Risks are based on the National Academy of Science’s lifetime fatal cancer unit risk or radon in drinking water of 6.7 x 10 ¥7. 3 USEPA 1999j.

A second ‘‘worst case’’ evaluation was

performed using four scenarios with

high radon influent levels (ranging from

1,323 pCi/L to 110,000 pCi/L) and/or

high flows to further determine whether

individuals living near water treatment

plants would experience significant

increases in cancer risks due to radon

off-gas emissions. For this analysis, the

MINEDOSE model was used in

conjunction with radon emissions

estimates to estimate lifetime fatal

cancer risks for individuals living near

the modeled facility. Emissions were

estimated using MINDOSE 1.0 (1989), a

predecessor to COMPLY–R (1.2), which

can be downloaded from the EPA

homepage (http://www.epa.gov/

rpdweb00/assessment/comply.html).

Comply–R (1.2, radon-specific) is

intended for demonstrating compliance

with the National Emissions Standards

for Hazardous Air Pollutants

(NESHAPS) in 40 CFR 61, Subpart B,

which are the Federal standards for

radon emissions from underground

uranium mines. While these standards

do not apply to drinking water facilities,

the model can be used to estimate radon

exposures from aeration vents at

drinking water facilities. To check for

consistency between MINEDOSE and

COMPLY–R, several modeling scenarios

done in the original analysis with

MINEDOSE were repeated using

COMPLY–R and the results from

MINEDOSE were found to be

conservative with respect to the

COMPLY-R results, i.e., COMPLY–R

predicts lower exposures for the

scenarios modeled. The MINEDOSE

code was originally used instead of the

AIRDOS code because of its relative

ease of use. When modeling the same

scenarios with MINEDOSE and

AIRDOS, the predicted exposures were

determined to be similar enough to

warrant the use of MINEDOSE for this

work. The results from the MINEDOSE

modeling work and subsequent work

(USEPA 1994a) concluded that even

these ‘‘worst case maximum individual

risks’’ from radon off-gas were much

smaller (300 to 1,000 times smaller)

than the average individual risks posed

by the untreated water.

(ii) Permitting of Radon Off-Gas from

Drinking Water Facilities. Radon

emissions to ambient air are only

Federally regulated under 40 CFR 61,
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59291

National Emission Standards for

Hazardous Air Pollutants (NESHAPs).

These regulations apply to radon

emissions under very specific

circumstances, including emissions of

radon to ambient air from uranium mine

tailings, phosphogypsum stacks (40 CFR

61, Subpart R), Department of Energy

storage and disposal facilities for

radium-containing materials (40 CFR 61,

Subpart Q), and underground uranium

mines (40 CFR 61, Subpart B). At

present, there are no State or Federal

regulations that directly apply to radon

air emissions from water treatment

facilities.

To assess potential procedures (e.g.,

permit applications, off-gas risk

modeling) and costs that could be

associated with radon off-gas from

aeration facilities, EPA gathered

information from agencies responsible

for air permitting (USEPA 1999h), using

California as a case study. California air

permitting requirements are expected to

be more restrictive than most States, and

for this reason, it is considered a

conservative case study. The

information gathered is not expected to

be nationally representative, but is

illustrative as a ‘‘worst case scenario’’.

EPA contacted representatives from

nine air districts in California via

telephone to determine the likely

response of their district to

promulgation of a radon rule with an

associated radon MCL requirement

(USEPA 1999h). The air boards were

chosen to represent large, metropolitan

areas, medium-sized cities, and smaller,

more rural areas. The representatives

responded to the following questions:

• What is the likely response of your

permitting board to water systems

installing aeration treatment to comply

with the radon rule?

• What are the likely permitting

procedures and costs for water systems

installing aeration for radon? Who

would be responsible, the permitting

board or the water system, for carrying

out each procedure and paying the

costs?

• Will large water systems and small

water systems follow different

procedures, or are procedures uniform

regardless of water system size (e.g., offgas volume)? How do permitting costs

change with the applicant’s system size?

• Will water systems be required to

perform off-gas risk modeling as part of

the permitting procedure or will they be

required to do other environmental

impact analyses?

• Would there be annual renewal

procedures (e.g., reapplication,

compliance monitoring) and costs? Who

would be responsible for carrying our

the procedures and bearing the costs?

• Is ongoing monitoring likely to be

required?

Where possible, representatives

provided estimates of time and cost that

could be incurred by water systems and

the districts as a result of the potential

district response to the radon rule.

Responses to these questions

indicated that the likely response to a

radon rule is similar across the

California air districts contacted. Most

districts indicated they are likely to

follow the lead of the State. ‘‘Following

the State’s lead’’ means that, if the State

includes radon on its Toxic Air

Contaminants List and establishes

potency factors (unit risk factors and

expected exposure levels for radon), air

districts will probably regulate drinking

water system aeration facilities through

permits. Permitting procedures are

similar across air districts and generally

do not vary for facilities of different

sizes. However, permitting costs and

who bears those costs can vary

significantly from air district to air

district. Some portion of the costs are

likely to vary based on facility size or

emissions level.

Currently, ‘‘radionuclides’’ (which

includes radon) are on the Toxic Air

Contaminant Identification List

developed by the California Air

Resources Board. Listed contaminants

are categorized by priority, and

depending on what category a substance

is in, the substance may or may not have

‘‘potency factors’’ developed by

California’s Office of Environmental

Hazard Health Assessment (OEHHA). At

the present time, radon is ‘‘Category

4A’’, which means that OEHHA is not

currently planning on publishing values

for the radon unit risk factor and

reference exposure level, indicating that

air boards are not likely to require

permitting for radon off-gas at the

present time. However, radon has been

proposed for elevation in priority to

‘‘Category 3’’, which means that it could

be a candidate for the development

potency numbers in the future. Since

California air quality districts generally

follow the lead of OEHHA, if OEHHA

publishes a unit risk factor and

reference exposure level for radon in the

future, air districts are then likely to

evaluate whether radon should be

considered in their air permitting

programs. If OEHHA decides not to

establish potency factors for radon,

California air districts are not likely to

require permitting for radon off-gas from

drinking water treatment plants.

Respondents indicated that typical

permitting procedures were: a system

applies for a permit to construct; the

board evaluates the application and

decides whether or not to issue a

permit; a permit may then be issued,

after which the system may construct

the aerator; the District conducts an

inspection and the system may or may

not have to perform testing; a public

notice is issued if required by risk level

and proximity of schools; the District

issues a permit to operate; system must

annually renew the permit (no

monitoring or inspection likely). It is

likely that water systems in the more

densely populated, Metropolitan areas

are more likely to need to do a risk

assessment and perform modeling as

part of their permit application.

Permitting costs ranged from < $500 for

simple permitting up to $50,000 for

more complicated situations, with

typical permitting costs reported in the

$1,000 to $5,000 range. These costs do

not include any radon dispersion

controls or other engineering controls

that might be required for the permit.

(b) Centralized Liquid Phase Granular

Activated Carbon (GAC) and Point-ofEntry GAC. GAC removes radon from

water via sorption. ‘‘Downflow’’ designs

are used, in which the raw water is

introduced at the top of the carbon bed

and flows under pressure downwards

through the bed. The treated water may

then be disinfected or otherwise posttreated and piped to the distribution

system. Advantages to the use of GAC

relative to aeration include the lack of

a need to break pressure (and hence repump), the lack of radon off-gas

emissions, and, in very small systems

applications with good water quality,

GAC typically has no moving parts and

requires little maintenance. Details

regarding the process of radon removal

via GAC are provided elsewhere

(USEPA 1999h, AWWARF 1998a,b).

This discussion will focus on potential

issues that small water systems may face

if they choose GAC for radon removal.

Of these, raw water quality is of

paramount concern since it affects

radon removal efficiency, unit lifetime,

and the potential for secondary

radiation hazards. Radon, iron,

uranium, and radium levels are most

important.

(i) Radon Influent Levels for POE

GAC: Gamma Radiation Hazards. An

upper limit of 5,000 pCi/L of radon in

influent water being treated by POE

GAC is suggested by Rydell et al. (1989)

and Kinner et al. (1990b) to protect

persons in frequent proximity to the

carbon bed (i.e., residents) from gamma

ray exposures. This influent level is

based on a residential exposure limit of

170 mRem/year, or 0.058 mR/hour

based on 8 hours/day of maximum

exposure, 365 days per year. The 170

mRem/year limit was established by the

National Council on Radiation
59292 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

Protection Bulletin (cited by Rydell et

al. 1989). Note that this residential

exposure limit is less conservative than

the EPA recommended limit of 100

mRem/year for water treatment plant

personnel. However, the assumption of

8 hours/day of maximum proximity is

extremely conservative. The 100 mRem/

year limit is achieved if a person gets

maximum exposure for approximately 5

hours per day or less, 365 days per year,

which is still a conservative

assumption.

Rydell et al. determined this influent

limit based on an empirical and

theoretical relationship between radon

influent level and gamma ray emissions

from the carbon bed. As will be

discussed next, based on recent work

using improved gamma ray detection

methodology, Hess et al. (1998) report

that this limit may be too low by a factor

of 2, i.e., the suggested radon influent

limit may be closer to 10,000 pCi/L.

Note that these limits are based on

assumptions about GAC contact basin

configurations, type and extent of

shielding, length of time and proximity

of persons to the unit, etc. While the

‘‘rules-of-thumb’’ described previously

are useful, appropriate radon influent

limits may be higher or lower

depending upon site-specific

considerations and should be

determined on a case-by-case basis.

The University of Maine reported

results on the removal of radon from

drinking water using GAC (Hess et al.

1998). Nine carbon beds (all in Maine),

which had been in use for more than 10

years by public water systems and

private homes for radon removal, were

studied. Radon influent levels ranged

from 330 to 107,000 pCi/L, with a mean

of 24,500 pCi/L and a standard

deviation of 11,800 pCi/L. Gamma ray

emissions from the GAC units and

accumulated radon progeny, uranium,

and radium were analyzed. Gamma ray

emissions from the GAC surface ranged

from 11.5 uR/h to 301 uR/h, with a

mean of 78 uR/h and a standard

deviation of 82 uR/h, and were 2 to 4

times lower than predicted by theory.

The authors concluded that the limit of

5,000 pCi/L suggested by Rydell et al.

(1989) may be too low by a factor of 2

or more.

(ii) Radon Influent Levels for

Centralized GAC: Gamma Radiation

Hazards. Using the very conservative

assumption that a water treatment

operator will be in close proximity for

40 hours per week, the 100 mRem/year

translates to around 0.05 mR/hour,

which also corresponds to a maximum

of 5,000–10,000 pCi/L of radon for small

flows. However, since GAC is likely to

be used only by very small water

systems and does not involve intensive

O&M, much shorter work weeks are

likely. Using 10 hours/week, the

maximum radon influent level would be

higher. Again, these are ‘‘rule-of-thumb’’

suggestions only. The best means to

ensure that 100 mRem/year maximum

exposure limits are maintained is to

implement appropriate monitoring of

gamma levels in the treatment facility

and to ensure that proper shielding and

worker proximity restraints are

engineered to minimize exposures.

(iii) Other Water Quality

Considerations: Naturally-Occurring

Iron and Dissolved Organic Materials.

The adsorption of iron precipitates can

reduce a unit’s radon removal

efficiency, so that the raw water may

need to be pre-treated to stabilize and/

or remove the dissolved iron. The

American Water Works Association

Research Foundation (AWWARF

1998a,b) reports that waters with low

iron and low levels of naturally

occurring organic matter (‘‘total organic

carbon’’, TOC) can achieve good radon

steady-state removals (i.e., radon

sorption equals radon decay), but that

the negative effects of iron and TOC on

removal efficiencies may necessitate

pilot testing to ensure proper contactor

design. For raw water with high iron

and/or TOC, pre-filtration or preoxidation/filtration may be required to

achieve good steady-state removals.

(iv) Other Water Quality

Considerations: Naturally-Occurring

Uranium and Radium: Uranium and

radium raw water levels are also of

concern since sorption may occur onto

the GAC surface, which results in

uranium and radium occurrence in the

GAC filter backwash residuals and

ultimately may create a final GAC bed

disposal problem. Water quality (pH,

iron levels, natural organic matter

levels, alkalinity, etc.) determine the

extent to which uranium and radium

sorb to the GAC surface. AWWARF

(1998b) reported results from case

studies conducted over a two year

period in New Hampshire, New Jersey,

and Colorado, including findings

regarding loadings of uranium and

radium on the GAC surface and

respective levels in backwash residuals.

Radon influent levels were 15,000–

17,000 pCi/L, 2,220 pCi/L, and <7,500

pCi/L at the New Hampshire, New

Jersey, and Colorado sites, respectively.

In the New Hampshire pilot study,

backwash residuals contained ∼200 pCi/

g uranium and ∼50 to 60 pCi/g radium.

For water treatment residuals with

uranium levels between 75 and 750 pCi/

g, EPA suggests that disposal measures

be determined on a case-by-case basis

(USEPA 1994b). In general, disposal in

a controlled landfill environment may

be necessary. The GAC bed itself

accumulated less than the limit of 75

pCi/g for all but one of the five GAC

columns in New Hampshire. For the

New Jersey and Colorado pilot plants,

uranium, radium, and radon progeny

levels were low enough in the backwash

residuals and the GAC bed that special

disposal considerations were not an

issue. It should be noted that State

disposal restrictions may be more

stringent than EPA’s suggestions, which

may make GAC a less attractive

alternative in these States.

(v) GAC Disposal Issues. Radon

progeny (e.g., Pb–210, a beta emitter)

accumulation is also related to radon

influent level. If radon influent levels

are high, the GAC unit lifetime may

decrease significantly, where this

lifetime is defined as the length of time

between start-up and when an

unacceptable accumulation of

radioactive Pb–210 occurs. While no

Federal agency currently has the

legislative authority to regulate the

disposal of wastes generated by water

treatment facilities on the basis of

naturally occurring radioactive

materials (NORM), EPA (USEPA 1994b)

suggests that NORM solid wastes with

radioactivity above 2,000 pCi/g be

disposed of in appropriate low-level

radioactive waste facilities.

Furthermore, given the prohibitive

expense and burden of disposing of lowlevel radioactive waste, EPA would

suggest that water treatment facilities

avoid situations where such high waste

levels would expected to potentially

occur. In the case of wastes containing

Pb–210, EPA suggests that case-by-case

determinations be made for determining

appropriate disposal. In summary, for

higher radon influent levels, shorter bed

lifetimes may be appropriate to reduce

Pb–210 build-up.

Hess et al. (1998), cited previously,

also studied several methods of cleaning

the GAC bed by removing Pb–210 and

radium from the spent GAC with

various chemical cleaning solutions

(e.g., solutions of hydrochloric acid,

nitric acid, sodium hydroxide, etc.).

Disposal of the cleaned GAC and the

much smaller volume of concentrated

radon progeny and radium is expected

to be cheaper in some cases than

disposal of the contaminated GAC bed

to a controlled disposal-facility. The

authors concluded that several of the

cleaning solutions (hydrochloric acid at

1 mole/liter, nitric acid at 0.5 mole/liter,

and acetic acid 0.5 mole/liter in

quantities of 150 mL solution per 100

grams of carbon) show promise.

Precipitates on the GAC surface

(including iron oxides, sorbed radium
Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules 59293

and radon progeny, including Pb–210)

were effectively removed. Removal

efficiencies for Pb–210 ranged from 30

percent to 70 percent and radium

removals from 70 to 90 percent. This

work indicates that a viable system of

collecting and cleaning spent GAC

material may be feasible, potentially

making GAC a more attractive small

systems alternative. Work supporting

programs of this type deserves further

consideration.

(vi) The American Water Works

Association Research Foundation

Report on Radon Removal Using GAC.

The American Water Works Association

Research Foundation (AWWARF

1998a,b) has recently reported on radon

removal by GAC. AWWARF suggests

that water systems with design flows

below 70 gallons per minute may want

to evaluate GAC and POE GAC as

potential radon removal technologies

(AWWARF 1999a), but warns that they

appear to be attractive technologies only

for very small systems with radon

influent levels below 5,000 pCi/L, iron

and manganese levels low enough not to

warrant pre-treatment, and uranium and

radium levels low enough not to

accumulate to levels of concern on the

GAC bed (USEPA 1994b). These

findings are generally consistent with

EPA’s findings.

B. Analytical Methods

1. Background

The SDWA directs EPA to set a

contaminant’s MCL as close to its MCLG

as is ‘‘feasible’’, the definition of which

includes an evaluation of the feasibility

of performing chemical analysis of the

contaminant at standard drinking water

laboratories. Specifically, SDWA directs

EPA to determine that it is economically

and technologically feasible to ascertain

the level of the contaminant being

regulated in water in public water

systems (Section 1401(1)(C)(i)).

NPDWRs are also to contain ‘‘criteria

and procedures to assure a supply of

drinking water which dependably

complies with such [MCLs]; including

accepted methods for quality control

and testing procedures to insure

compliance with such levels. * * *’’

(Section 1401(1)(D)).

To comply with these requirements,

EPA considers method performance

under relevant laboratory conditions,

their likely prevalence in certified

drinking water laboratories, and the

associated analytical costs. A critical

part of the method performance

evaluation involves an analysis of interlaboratory collaborative study data. This

analysis allows EPA to confirm that the

method provides reliable and repeatable

results when used within a given

laboratory and when used ‘‘identically’’

in other standard laboratories. Other

technical limitations, e.g., sampling and

sample preservation requirements,

requirements for non-standard

apparatus, and hazards from

wastestreams, are also considered.

In particular, the reliability of

analytical methods at the maximum

contaminant level is critical to the

implementation and enforcement of the

NPDWR. Therefore, each analytical

method considered was evaluated for

accuracy, recovery (lack of bias), and

precision (good reproducibility over the

range of MCLs considered). The primary

purpose of this evaluation is to

determine:

• Whether currently available

analytical methods measure radon in

drinking water with adequate accuracy,

bias, and precision;

• If any newly developed analytical

methods can measure radon in drinking

water with acceptable performance;

• Reasonable expectations of

technical performance for these

methods by analytical laboratories

conducting routine analysis at or near

the MCL levels (interlaboratory studies);

and

• Analytical costs. The selection of

analytical methods for compliance with

the proposed regulation includes

consideration of the following factors:

(a) Reliability (i.e., Precision/

accuracy of the analytical results over a

range of concentrations, including the

MCL);

(b) Specificity in the presence of

interferences;

(c) Availability of adequate equipment

and trained personnel to implement a

national compliance monitoring

program (i.e., laboratory availability);

(d) Rapidity of analysis to permit

routine use; and

(e) Cost of analysis to water supply

systems.

2. Analytical Methods for Radon in

Drinking Water

(a) Proposed Analytical Methods for

Radon. The analytical methods

described here are the testing

procedures EPA identified and

evaluated to insure compliance with the

MCL and AMCL. Two analytical

methods for radon in water that fit

EPA’s criteria for acceptability as

compliance monitoring methods were

identified: Liquid Scintillation Counting

(LSC) and the de-emanation method.

The LSC method is here defined as

Standard Method 7500-Rn, SM 1995;

the de-emanation method is described

in the report, ‘‘Two Test Procedures for

Radon in Drinking Water,

Interlaboratory Study’’ (USEPA 1987).

EPA believes these methods are

technically sound, economical, and

generally available for radon

monitoring, and is proposing their use

for monitoring to determine compliance

with the MCL or AMCL. The reliability

of these methods has been demonstrated

by a history of many years of use by

State, Federal, and private laboratories.

Both methods have undergone

interlaboratory collaborative studies

(multi-laboratory testing), demonstrating

acceptable accuracy and precision.

Thirty-six laboratories participated in

the interlaboratory study for Standard

Method 7500-Rn and sixteen labs in the

de-emanation study. The American

Society for Testing and Materials

(ASTM) has also published an LSC

method (ASTM 1992). Although its

collaborative study (15 participating

laboratories) was conducted at radon

sample concentrations greater than

1,500 pCi/L, it is substantially

equivalent to Standard Method (SM)

7500-Rn. EPA is proposing that ASTM

D–5072–92 serve as an alternate method

for radon for both the MCL and AMCL,

under the restriction that the quality

controls from SM 7500-Rn are met;

namely, that the relative percent

differences between duplicate analyses

are less than the 95 percent confidence

level counting uncertainty, as defined in

SM 7500-Rn. Table VIII.B.1 summarizes

the proposed analytical methods for

radon in drinking water.
59294 Federal Register / Vol. 64, No. 211 /Tuesday, November 2, 1999 / Proposed Rules

TABLE VIII.B.1.—PROPOSED ANALYTICAL METHODS FOR RADON IN DRINKING WATER

Method

References (method or page number)

SM ASTM EPA

Liquid Scintillation Counting ............................................................................................................. 7500–Rn1 D 5072–92 2

De-emanation ................................................................................................................................... .................... .................... EPA 1987 3

Notes:

1Standard Methods for the Examination of Water and Wastewater. 19th Edition Supplement. Clesceri, L., A. Eaton, A. Greenberg, and M.

Franson, eds. American Public Health Association, American Water Works Association, and Water Environment Federation. Washington, DC.

1996. 2American Society for Testing and Materials (ASTM). Standard Test Method for Radon in Drinking Water. Designation: D 5072–92. Annual

Book of ASTM Standards. Vol. 11.02. 1996. 3Appendix D, Analytical Test Procedure, ‘‘The Determination of Radon in Drinking Water’’. In ‘‘Two Test Procedures for Radon in Drinking

Water, Interlaboratory Collaborative Study’’. EPA/600/2–87/082. March 1987. p. 22.

Other analytical methods were

evaluated, but they failed at least one of

the criteria described previously. These

methods included an ‘‘activated

charcoal passive radon collector’’, a ‘‘degassing Lucas Cell’’ technique (a variant

of the de-emanation method), the

‘‘electret ionization chamber system’’,

and a ‘‘delay-coincidence liquid

scintillation counting system’’. All of

these methods are described and

evaluated elsewhere (USEPA 1999g). As

described next, if EPA implements the

‘‘Performance Based Measurement

System’’ (PBMS) program, then any

method that performs according to

specified criteria may be used for

compliance monitoring. (b) Summary of Methods. Analysis of

radon in drinking water by the LSC

method involves preparation of the

water sample (ca. 20 mL), which

includes the selective partitioning of

radon from the water sample into a

water-immiscible mineral-oil

scintillation cocktail and allowance for

equilibration of radon-222 with its

progeny. The prepared sample is then

analyzed with an alpha-particle

counting system that is optimized for

detecting radon alpha particles.

Scintillation counting methods are

discussed later. One of the advantages of

transferring the radon from the water

sample into the water-immiscible

cocktail is that potential interferents

(other alpha emitters) are left behind in

the water phase. The de-emanation method involves

bubbling radon-free helium or aged air

(low background radon) through the

water sample into an evacuated

scintillation chamber. After equilibrium

is reached (3 to 4 hours), this chamber

is placed in a counter and the resulting

scintillations are counted. This method

generally allows measurement of lower

level of radon than does low volume

direct liquid scintillation. However, this

method is more difficult to use,

requiring specialized glassware and

skilled technicians. Regions of the

country with high radon levels in water

(e.g., New Hampshire and Maine) may

experience problems with this method,

since the high radon levels in the

samples can cause high backgrounds in

the Lucas cell, forcing retirement of the

cell for extended periods. (c) Alpha Particle Counting Methods

for Radon-222. One of the distinct

characteristics of alpha particles is that

they exhibit an intense loss of energy as

they pass through matter, due to strong

interactions between the alpha particles

and the surrounding atoms. This intense

loss of energy is used in differentiating

alpha radioactivity from other types.

Some of the alpha particle’s energy loss

is due to its ionization of atoms with

which it comes in contact. Alpha

particle detection is based on this

phenomenon: when alpha particles

ionize the phosphor coating of a

detector, the energized phosphor

‘‘scintillates’’ (or emits light). The

resulting light (or scintillations) are then

detected and quantified with an

appropriate detector that is calibrated to

determine the concentration of the

alpha emitter of interest. There are

variants of detectors that measure these

interactions, but this discussion will

focus on the type relevant to the LSC

and Lucas Cell methods.

In scintillation counting, the alpha

particle transfers energy to a scintillator

medium, e.g., a phosphor dissolved in a

solvent ‘‘cocktail’’, which is enclosed

within a ‘‘light-tight’’ container to

reduce background light. The

scintillation cocktail serves two roles: it

contains the phosphor which is

involved in quantifying the radon

activity (concentration) and it

selectively extracts the radon from the

water sample, leaving behind other

alpha emitters that may interfere with

the analysis. The transfer of energy from

the radon-derived alpha particles to the

phosphor dissolved in the scintillator

medium results in the production of

light (scintillation) of energies

characteristic of the phosphor and with

an intensity proportional to the energy

transmitted from the alpha particles,

which are the ‘‘signature’’ of radon-222.

A ‘‘counter’’ records the individual

amplified pulses which are proportional

to the number of alpha particles striking

the scintillation detector, which is

ultimately proportional to the radon

activity in the original sample. The

scintillation cell system used for the

liquid scintillation method is as

described previously. The system used

for the de-emanation method is similar,

with the exception that a scintillation

flask (‘‘Lucas Cell’’, a 100–125 ml metal

cup coated on the inside with a zinc

sulfide phosphor and having a

transparent window) replaces the liquid

scintillation medium described. A

counting system compatible with the

scintillation flask is incorporated to

quantify the radon concentration in the

sample. Since radon has a short decay

period (half-life of 3.8 days), correction

methods are employed to account for

the radon that decayed between the time

of sample collection and the end of the

analysis.

(d) Sampling Collection, Handling,

and Preservation. In order to ensure that

samples arriving at laboratories for

analysis are in good condition, EPA is

proposing requirements for sample

collection, handling and preservation.

When sampling for dissolved gases

like radon, special attention to sample

collection is required. Either the sample

collection method described in SM

7500-Rn, the VOC sample collection

method, or one of the methods

described in ‘‘Two Test Procedures for

Radon in Drinking Water,

Interlaboratory Collaborative Study’’

(USEPA 1987) should be used. In

addition, because dissolved radon tends

to accumulate at the interface between

a water sample and some types of

plastic containers, glass bottles with

teflon lined caps must be used. Finally,

EPA’s assessment of laboratory

performance is premised on the

assumption that sample analysis occurs

no later than 4 days after collection.

Laboratories unable to comply with this

holding time limit may have difficulty

performing within the estimated

precision and accuracy bounds. EPA

solicits public comment on the

proposed sample collection procedures

for radon in drinking water.