EPA 815-Z-99-006
Tuesday
November 2, 1999
Part II
Environmental
Protection Agency
40 CFR Parts 141 and 142
National Primary Drinking Water
Regulations; Radon-222; Proposed Rule
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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
OtO-0
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 non-
MMM 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 hand-
delivered 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
et@epamail.epa.gov. Electronic
comments must be submitted as an
ASCII, WP6.1, or WPS 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, WPS, 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)(l) 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
Industry
State, Tribal,
and Local
Government.
Federal Gov-
ernment.
Examples of potentially regu-
lated entities
Privately owned/operated
community water supply
systems using ground
water or mixed ground
water and surface water.
State, Tribal, or local govern-
ment-owned/operated
water supply systems
using ground water or
mixed ground water and
surface water.
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
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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
SOW A: 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 Radon-
222
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 Non-
MMM 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
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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 (SOWA), 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 statutory-
based framework reflects the
characteristics uniquely specific to
radon among drinking water
contaminants: that the relative cost-
effectiveness 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
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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 non-
transient 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 cost-
effective 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 cost-
effective 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 cost-
effective 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.I and 1.2 provide a
conceptual model for the MCL, AMCL,
and MMM programs for small and large
systems.
BILLING CODE 6560-iiO-P
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FIGURE 1.1
Conceptual Model for the MCL, AMCL, and MMM Program
(Small Systems)
YES
State prepares and
submits
MMM program plan
YES
State decides
whether to
develop MMM
program plan
NO
CWS shall prepare
and submit MMM
program plan or
may elect to
comply with MCL
NO
EPA
approves
MMM
program plan
CWS meets
AMCL and
MMM program
implemented
NO
NO
EPA reviews State MMM program
every 5 years
State reviews CWS MMM program
every 5 years
NO
State
approves
MMM
program plan
CWS meets
AMCL and
MMM program
implemented
CWS complies
with MCL
YES
YES
KEY:
S\ = Decision Point
I I = Required Action
NOTE: The regulatory expectation for small systems is compliance with the AMCL if there
is an approved State MMM program, or implementation of a CWS MMM program (in the
absence of a State MMM program. Small systems may elect to comply with the MCL instead
of implementing an MMM program.
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59251
FIGURE 1.2
Conceptual Model for the MCL, AMCL, and MMM Program
(Large Systems)
State decides
whether to
develop MMM
program plan
YES
State prepares and
submits
MMM program plan
EPA
approves
MMM
program plan
CWS meets
AMCL and
MMM program
implemented
YES
EPA reviews State MMM program
every 5 years
State reviews CWS MMM program
every 5 years
NO
NO
NO
NO
NO
CWS complies
with MCL
YES
CWS shall comply
with MCL or may elect
to prepare and
submit MMM
program plan
State
approves
MMM
program plan
CWS meets
AMCL and
MMM program
implemented
YES
KEY:
\ / = Decision Point
I I = Required Action
BILLING CODE 6S60-50-C
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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 arid 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 State-
approved 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 State-
approved 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 radon-
resistant
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.
/. 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.
/. 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 low-
flow 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 VILE
for discussion of compliance dates). If
the results of analyses show that trie
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 Vz 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 Vz 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
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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 non-
treated 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 ra.don, 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
14l5.a of the SDWA)
States and Tribes with primary
enforcement responsibility ("primacy")
may issue a variance under Section
1415(a)(l)(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.
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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
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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
forRadon-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 non-
community system does not serve year-
round residents; rather, it (1) regularly
serves at least 25 of the same persons
over 6 months of the year (a "non-
transient" 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 non-
transient 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
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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 non-
threshold 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
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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
SOW A) 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 equity-
related 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
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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 State's 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
iri 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. (I) 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
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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 cost-
effective 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 cost-
effective. However, it is also cost-
effective 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 radon-
resistant 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 radon-
resistant 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)(l) 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. (I) 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)(l) 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
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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 radon-
resistant. 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 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
19991).
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 radon-
resistant 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 radon-
resistant. 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
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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 Non-
MMM 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 program-
either 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 cost-
effective 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 radon-
resistant 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 radon-
resistant. 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
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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 cost-
effective 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 State-
approved 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 VIA. 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 5»/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
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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 radon-
resistant). 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 SOW A] 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
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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 radon-
resistant 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 rand 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
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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 radon-
resistant 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.
/. 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
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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 self-
sustaining 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 radon-
resistant 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 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 cost-
effective. However, it is also cost-
effective 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
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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
FR4511, August 19, 1998), EPAstated
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 cost-
effective way to reduce radon risk than
compliance with the MCL. (While EPA
believes that the MMM approach is
preferable for small systems in a non-
MMM 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 VIA 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 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 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 cost-
effective 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 non-
fatal 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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59269
a long-standing policy that drinking
water standards should limit risk to
within a range of approximately 10 ~4 to
10 -* 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 (S1997) to value the
avoided fatal cancers and a valuation of
$536,000 (SI997) 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 non-
quantified 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 non-
quantified 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 non-
fatal 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/1, 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 benefit-
cost 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).
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59270
Federal Register/Vol. 64, No. 211/Tuesday, November 2, 1999/Proposed Rules
TABLE VII.1.—EVALUATION OF RADON LEVELS
Radon level
(pCi/L)
4000
2000
•|000
500
300
100 -
Fatal cancer
cases
avoided
2.9
7.3
17.8
37.6
62.0
120.0
Individual fatal lifetime
cancer risk
26.8 in 10,000 ....
13.4 in 10,000
6.7 in 10,000
3.35 in 10,000
2.0 in 10,000
0.67 in 10,000
Cost per
fatal cancer
case avoid-
ed
($M)
14.9
9.5
7.3
6.8
6.6
6.8
Total na-
tional
costs 1
$M
43.1
69.7
130.5
257.4
407.6
816.2
Monetized
be'nef its 1
$M
17.0
42.7
103
219
362
702
Benefit-cost
ratio
0.4
0.6
0.8
0.9
0.9
0.9
1 Water 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 standard-
setting 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 cost-
effective 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
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Federal Register/Vol. 64, No. 211/Tuesday, November 2, 1999/Proposed Rules
59271
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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)(l) 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 non-
MMM 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
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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.I summarizes the
BAT findings by EPA for the removal of
the subject drinking water
contaminants, including a summary of
removal capabilities.
TABLE Vlll.A.1—PROPOSED BAT AND
ASSOCIATED CONTAMINANT RE-
MOVAL EFFICIENCIES
High Perform-
ance Aer-
ation 1 .
Up to 99.9% Removal.
Note: (1) High Performance Aeration is de-
fined 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 tech-
nologies, 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-of-
entry 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 population-
served 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 VII1.A.2.-
PROPOSED SMALL SYSTEMS COMPLIANCE TECHNOLOGIES (SSCTS)1 AND ASSOCIATED CONTAMINANT
REMOVAL EFFICIENCIES
Small systems compliance technology
Packed Tower Aeration (PTA)
High Performance Package Plant
Aeration (e.g., Multi-Stage Bubble
Aeration, Shallow Tray Aeration).
Diffused Bubble Aeration
Tray Aeration
Spray Aeration
Mechanical Surface Aeration
Centralized granular activated carbon
Affordable listed small
systems categories2
All Size Categories
All Size Categories
All Size Categories
All Size Categories
All Size Categoriss
All Size Categories
May not be affordable, except for
very small flows.
Removal efficiency
90- > 99.9% Removal
90— > 99 9% Removal
70 to > 99% removal
80 to > 90%
80 to > 90%
> 90%
50 to > 99% Removal
Operator
level re-
quired 3
Intermediate
Basic to Inter-
mediate.
Basic
Basic
Basic
Limita-
tions
(see
foot-
notes)
(»)
(a)
(a, b)
(a, c)
(a d)
{a, c)
(0
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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
, _. tonci
vated carbon.
Affordable listed small
systems categories z
ing fewer than 500 persons..
Removal efficiency
50 to > 99% Removal
Operator
level re-
quired 3
Basic
Limita-
tions
(see
foot-
notes)
v. &
Notes- 1 The Act (Section 1412(b)(4)(E)(ii)) specifies that SSCTs must be affordable and technically feasible for small systems.
2 This 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 p) those serving more than 3,300, but fewer than 10,001. ...,..,. ^ o
a From National Research Council. Safe Water from Every Tap: Improving Water Service to Small Communities. National Academy Press.
Washington, DC. 1997.
Limitations- Pre-treatment to inhibit fouling may be needed. Post-treatment disinfection and/or corrosion control may be needed.
ft) May not be as efficient as other aeration technologies because it does not provide for convective movement of the water, which reduces the
airwater contact. It is generally used in adaptation to existing basins. , , ., . . ,
«=> 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
In single pass mode, may be limited to uses where low removals are required. In multiple pass mode (or with multiple compartments), high-
er removals may be achieved, .
(<=) May be most applicable for low removals, since long detention times, high energy consumption, and large basins may be required for larger
co 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, ra-
dium, and/or uranium build-up may make disposal costs prohibitive. Proper shielding may be required to reduce gamma emissions from the GAG
unit. GAG may be cost-prohibitive except for very small flows. • . .
When POE devices are used for compliance, programs to ensure proper long-term operation, maintenance, and monitoring must be pro-
vided 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 rule-
making 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 19981,
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
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59275
costs for aeration (80% removal
efficiency, with disinfection and scaling
inhibitor) are S190 per household per
year (S/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 GAG-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/LOGO GALLONS, LATE 1997 DOLLARS)
Aeration2
Aeration + disinfection
Granular Activated Carbon (QAC)
GAC +• disinfection
POE GAC + UV disinfection
25-100
2 06
3 44
034
1 71
16.99
100-500
0 71
1 09
2 16
254
14.03
Population
500-1,000
n ^Q
069
2 16
246
NA
Served
1,000-3,300
n 99
0 40
NA
NA
NA
3,300-
10,000
n -\c
0 22
NA
NA
NA
>1 0,000
n no— n ~\o
NA
MA
NA
Notes:
'Cost ranges are estimated from cost equations found in the radon Technologies and Costs document (EPA 1999h), as used in the radon
HRCCA(64 FR9559).
8 Aeration 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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Federal Register/Vol. 64, No. 211/Tuesday, November 2, 1999/Proposed Rules
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 19981). GAC
disposal costs are included in the GAC-
COST 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 non-
compliant 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 cost-
effective 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 bio-
fouling 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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59277
TABLE VIII.A.4.— CO-OCCURRENCE OF RADON WITH DISSOLVED IRON IN RAW GROUND WATER1.2 (4188 SAMPLES)
Radon
(pCi/L)
NO
<100
100-300
300-1,000
1 ,000-3,000
>3,000
Totals
Dissolved Fe (mg/L) (percent)
ND
0.67
2.17
• 7.55
18.89
6.42
2.10
37.80
<0.3
0.36
1.72
10.20
22.61
9.05
3.82
47.76
0.3-1.5
0.21
0.53
2.67
33.08
0.74
0.31
7.54
1.5-2.5
0.02
0.12
1.34
0.57
0.10
0.02
2.17
>2.5
0.31
0.48
1.74
1.31
0.62
0.26
4.72
Totals
1.57
5.02
23.50
46.46
16.93
6.51
100.00
Notes:
i Based on analyses as described in USEPA 1999c.
a The 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 «•2 (4189
SAMPLES)
Radon
(pCi/L)
NO
<100
100-300
300-1 ,000
1,000-3,000
>3,000
Totals
Dissolved Mn (mg/L) (percent)
ND
0.69
2.67
8.00
21.99
6.45
1.43
41.23
<0.02
0.26
0.84
5.97
11.84
5.90
3.39
28.20
0.02-0.05
0.05
0.36
2.20
3.17
1.24
0.53
7.55
>.050
0.57
1.15
7.33
39.48
3.34
1.17
23.04
Totals
1.57
5.02
23.50
46.48
16.93
6.52
100.00
Notes: » and *: 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 man-
ganese.
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 VIH.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 VIH.A.6.—CO-OCCURRENCE OF RADON WITH DISSOLVED COMBINED IRON AND MANGANESE IN RAW AND FINISHED
GROUND WATER
Ground water type
Finished Ground Water
Raw Ground Water
Percent of samples with
dissolved combined Fe
and Mn (mg/L) (percent)
<0.3
>81,>93
>85, >71
<1.5
>97 >99
>95 >88
Data sources
NIRS.1 AWWA Water:/
Stats2
NWIS,3 AWWA Water/Stats
Notes:
1 "National Inorganics and Radionuclides Survey": See USEPA 1999c for references.
2 American 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 "Waten/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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Federal Register/Vol. 64, No. 211 /Tuesday, November 2, 1999/Proposed Rules
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 pre-
and 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 post-
treatments 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 non-
compliant 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).
BILLING CODE 6560-50-P
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Federal Register/Vol. 64, No. 211 /Tuesday, November 2, 1999/Proposed Rules
59279
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BILLING CODE 6560-50-C
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59281
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 VHI.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.
BILLING CODE 6560-50-P
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59282
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59283
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 cost-
effective 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 pre-
treatment is required for iron and
manganese removal or if water must be
piped from the well-head to an off-site
area for treatment.
BILLING CODE 6560-50-P
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59284
Federal Register/Vol. 64, No. 211/Tuesday, November 2, 1999/Proposed Rules
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Federal Register/Vol. 64, No. 211/Tuesday, November 2, 1999/Proposed Rules
(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 19991) 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 lower-
and 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 low-
and 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 well-
demonstrated 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).
(1) 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 (DBFs) can be
formed depending on the disinfectant
used, the disinfectant concentration and
contact time, water temperature, the
levels of DBF 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
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used as a surrogate for formation of one
important class of DBFs, total
trlhalomethanes (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
DBF 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 DBF
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
DBFs and, thereby reducing potential
DBF risks and avoiding MCL violations
for the DBF 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
DBF formation should be implemented
(NRC 1997, NAS 1999b, Spencer etal
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 etal. 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 (FTA), simple spray
aeration, slat tray aeration, and free fall
aeration, with or without spray aerators.
Passive aeration processes such as free-
standing, 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 ainwater 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 airwater ratios like shallow tray
aeration (STA) or multi-stage bubble
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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 etal. 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 post-
treatments 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 sealant 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 ainwater
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
ainwater 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 airwater ratio designs.
MSBA units typically consist of shallow
(typically less than 1.5 feet deep) high-
density 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 airwater 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 ainwater interfacial area
for radon volatilization. In single pass
mode, depending upon the ainwater
ratio, removal efficiencies of >50 to >85
percent can be achieved. In multiple
pass mode, 99 percent removals can be
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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 ("low-
technology"), 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 low-
technology 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/rpdwebOO/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 x 10~5 for
individuals within 50 km of one of these
systems, with a maximiim 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 off-
gas 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 off-
gas 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.
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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. RisK1
Modeling scenario
20 Facilities Modeled:
1
2
3
4
5
6
7
8 »
9
10
11
12
13 .'.
14
15
16
17
18
19
20
Totals for All 20 Facilities
Totals Assuming All U.S.
All Systems Meet MCL
Community Water Systems Treat to 300 pCi/L3, i.e.,
of 300 pCi/L.
Totals Assuming All Small U.S. Drinking Water Facilities Treat to 4000 pCi/L3
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.
Totals Assuming All U.S. Drinking Water Facilities Treat to 4000 pCi/L3, i.e.,
All Systems meet MCL of 4000 pCi/L.
Concentration
in water
(pCi/L)
1,839
5,003
2,175
1,890
1,310
1,329
4,085
10,640
3,083
3,270
2,565
4,092
16,135
3,882
1,244
2,437
996
7,890
9,195
7,500
Emissions
from facility
(Ci Rn/Yr)
2.79
6.22
2.85
20.89
1.81
91.80
2.26
1.18
0.55
9.04
3.54
13.75
2.23
0.27
1.03
1.35
8.94
0.87
1.02
1.04
161
3700
1600
240
Maximum
lifetime indi-
vidual risk2
3x10-7
6x10-7
3x10-7
6x10-s
5x10-7
9x10-6
2x10-7
1 x10-7
5x10-8
2x10-5
7x10-6
2x10-7
2x10-7
8x10-s
3x10-7
4x10-7
9x10-7
3x10-7
3x10-7
3x10-7
Population
risk 2
(fatal cancer
cases per
year)
7x 10-5
2x10-"
9x 10-5
1 x10-«
9x10-7
1 x10~3
3x10-5
1 x10-s
7x10-6
1 x 10-3
6 x 10~4
3x10-5
3x10-5
5x 10-s
2x 10-5
5x10-7
2x10~4
6x10-6
1 xlO-5
6x10-6
0.004
0.09
0.04
0.01
Notes:
1 Estimates of Risk Assessment Using AIRDOS-EPA to estimate radon exposure. The total U.S. risk is based on the very conservative projec-
tion 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.
3USEPA1999J.
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 MlNDOSE 1.0 (1989), a
predecessor to COMPLY-R (1.2), which
can be downloaded from the EPA
homepage (http://www.epa.gov/
rpdwebOO/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,
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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., off-
gas 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-of-
Entry 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 post-
treated 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 re-
pump) , 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
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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 ef 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 etal. (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.
(Hi) 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 pre-
oxidation/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 low-
level 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 etal. (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
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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 FOE 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
I. 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(l)(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 inter-
laboratory 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.l summarizes
the proposed analytical methods for
radon in drinking water.
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TABLE Vlll.B.1.—PROPOSED ANALYTICAL METHODS FOR RADON IN DRINKING WATER
Method
De-emanation
References (method or page number)
SM
7500-Rn1
ASTM
D 5072-922
EPA
EPA 19873
Notes:
?Standard 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.
zAmerican Society for Testing and Materials (ASTM). Standard Test Method for Radon in Drinking Water. Designation: D 5072-92. Annual
BO°L^end™DSMaA^Tes\ Procedure,' "The Determination of Radon in Drinking Water". In "Two Test Procedures for Radon in Drinking
Water, Interlabo'ratory 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 "de-
gassing 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,
Intel-laboratory 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.
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59295
In discussions between EPA and the
water utility industry, concerns have
been expressed about the difficulties in
collecting samples and the requisite
skills that may be required. EPA
emphasizes that the skills required to
sample for radon are the same as those
required to sample for other currently
regulated drinking water contaminants,
namely volatile organic contaminants.
In addition, the 1992 EPA collaborative
study mentioned earlier evaluated four
sample collection techniques and found
them all capable of providing equivalent
results. Supplementing this study, EPA
has reviewed a sampling protocol for
radon in water developed by the
Department of Health Services Division
of Drinking Water and Environmental
Management (CADHS 1998). This
protocol employs one of the four
techniques evaluated by EPA, the
immersion technique.
Using the immersion technique, the
well is purged for 15 minutes by
running the sampling tap, to ensure that
a representative sample is collected.
After the purging period, a length of
flexible plastic tubing is attached to the
spigot, tap, or other connection, and the
free end of the tubing is placed at the
bottom of a small bucket. The water is
allowed to fill the bucket, slowly, until
the bucket overflows. The bucket is
emptied and refilled at least once.
Once the bucket has refilled, a glass
sample container of an appropriate size
is opened and slowly immersed into the
bucket in an upright position. Once the
bottle has been placed on the bottom of
the bucket, the tubing is placed into the
bottle to ensure that the bottle is flushed
with fresh water. After the bottle has
been flushed, the tubing is removed
while the bottle is resting on the bottom
of the bucket. The cap is placed back on
the bottle while the bottle is still
submerged, and the bottle is tightly
sealed. As noted in the California
protocol cited earlier, the choice of the
sample container is dependent on the
laboratory that will perform the
analysis, and will be a function of the
liquid scintillation counter that is
employed. If bottles are supplied by the
laboratory, there is no question of what
container to employ.
Once the sealed sample bottle is
removed from the bucket, it is inverted
and checked for bubbles that would
indicate headspace. If there are no
visible air bubbles, the outside of the
sealed bottle is wiped dry and cap is
sealed in place with electrical tape,
wrapped clockwise. After the sample
bottle is sealed, a second (duplicate)
sample is collected in the same fashion
from the same bucket. The date and
time of the sample collection is
recorded for each sample.
As can be surmised from the
description, the sample collection
procedures are not particularly labor
intensive. Most of the time is spent
allowing the water to overflow the
bucket. Likewise, there are no
significant manual skills required.
(e) Skill Considerations for Laboratory
Personnel While neither of these
techniques is difficult relative to
standard drinking water methods, a
discussion of the skills required to
employ the methods is appropriate.
Given the long history of successful use
of the liquid scintillation counting
technique (it has been used in medical
laboratories and environmental research
laboratories for well over 30 years), EPA
feels confident that State drinking water
laboratories will be able to adequately
use these methods. The skills required
are primarily the ability to transfer and
mix aliquots of the sample to a sealed
container for further analysis. The
counting process is highly automated
and the equipment runs unattended for
days, if needed.
The de-emanation process requires
somewhat more manual skill. As noted
in the 1991 proposed rule, EPA expects
that this technique would require
greater efforts be made to train
technicians than for the liquid
scintillation technique. The technique
requires that the counting cell be
evacuated to about 10 mTorr pressure
and then a series of stopcocks or valves
are manipulated to transfer the radon
that is purged from the sample into the
counting cell. Potential problems with
the analysis, such as a high background
level of radon that can develop over the
course of the day, or aspirating water
into the counting cell, can be minimized
by a well-trained analyst. However, as
EPA concluded in 1991, the Lucas cell
technique is not expected to form the
sole basis of a compliance monitoring
program for radon in drinking water.
(f) Cost of Performing Analyses. The
actual costs of performing analysis may
vary with laboratory, analytical
technique selected, the total number of
samples analyzed by a lab, and by other
factors. Based upon information
collected in 1991, the average sample
cost for radon in water was estimated to
be $50 per sample. EPA recently
updated this cost estimate to $57 per
sample (USEPA 1999b) by conducting a
similar survey of drinking water
laboratories. The data from the 1991 and
1998 surveys and the descriptive
statistics are summarized in Table
VIII.B.2. There was no clear correlation
between the estimated price and the
method cited by the laboratory. The
1998 range of prices brackets those
collected by EPA in 1991. It is expected
that the "market forces" generated by a
radon regulation will tend to lower per
sample costs, especially in light of the
fact the LSC is very amenable to
automation, with feed capacities of
more than 50 samples/load possible.
However, as will be discussed later,
there may be short-term laboratory
capacity issues that resist a lowering of
per sample prices.
TABLE VIII.B.2. RADON SAMPLE COST ESTIMATE
Arbitrary lab
No.
1
2
3
4
5
6
7
8
9
10 ,
11
12
Cost esti-
mate
$30
44
50
75
75
50
40
75
45
55
75
40
Year data
collected
1991
1991
1991
1998
1998
1998
1998
1998
1QQR
1998
1998
1998
Descriptive statistics for 1991
M ctMQ on HI M «M-7 nn o*j r,
Mean, ;t>49.ou, Median, $47.00, Std. Dev., $18.80; Range, $45; Minimum, $30; Maximum, $75.
Descriptive Statistics for 1 998 Data
iviudii, 3>oo.oo, ivieuian, q>o^.ou, old. uev., ;j>io.oU, Hange, $35; Minimum, $40; Maximum, $75.
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These cost data are preliminary and
may be different in practice for the
following reasons: (a) As the number of
experienced laboratories increases, the
costs can be expected to decrease; (b)
analytical costs are determined, to some'
extent, by the quality control efforts and
quality assurance programs adhered to
by the analytical laboratory; (c) per-
sample costs are influenced by the
number of samples analyzed per unit
time. EPA solicits comments on its cost
estimates from laboratories experienced
in performing these analyses.
(g) Method Detection Limits and
Practical Quantitation Levels. Method
detection limits (MDLs) and practical
quantitation levels (PQLs) are two
performance measures used by EPA to
estimate the limits of performance of
analytic chemistry methods for
measuring contaminants in drinking
water. An MDL is the lowest level of a
contaminant that can be measured by a
specific method under ideal research
conditions. EPA usually defines the
MDL as the minimum concentration of
a substance that can be measured and
reported with 99 percent confidence
that the true value is greater than zero.
The term MDL is used interchangeably
with minimum detectable activity
(MDA) in radionuclide analysis, which
is defined as that amount of activity
which in the same counting time, gives
a count which is different from the
background count by three times the
standard deviation of the background
count. A PQL is the level at which a
contaminant can be ascertained with
specified methods on a routine basis
(such as compliance monitoring) by
accredited laboratories, within specified
precision and accuracy limits.
The feasibility of implementing an
MCL at a particular level is in part
determined by the ability of analytical
methods to ascertain contaminant levels
with sufficient precision and accuracy
at or near the MCL. The proposed
methods demonstrate good
reproducibility and accuracy at radon
concentrations in the range of 150-300
pCi/L (half of the proposed MCL up to
the proposed MCL), as demonstrated in
the results from inter-laboratory studies.
In inter-laboratory studies (or
Performance Evaluation studies),
prepared samples of known
concentration are distributed for
analysis to participating labs, which
have no information on the
concentrations of the samples. The
results of the analyses by the
participants are compared with the
known value and with each other to
estimate the precision and accuracy of
both the methods used and the lab's
proficiency in using the method. Table
VIII.B.3 summarizes the statistical
results of these inter-laboratory studies
for the proposed methods.
In the 1991 proposed rule, EPA
proposed using both the MDL and PQL
as measures of performance for radon
analytical methods. EPA also proposed
acceptance limits based on the PQLs
that were derived from these
performance evaluation studies. The use
of acceptance limits was confusing to
commenters for various reasons. The
important issue is the observation that
true analytical method performance is
related to within-laboratory conditions
(including counting times in the case of
radiochemicals) and that acceptance
limits are based on multi-laboratory
Performance Evaluation studies. For
non-radiochemical contaminants this
issue is less troublesome because their
PQLs tend to be "fixed" since the MDLs
to which they are related reflect
optimized conditions for standard
laboratory equipment, whereas for
radiochemical contaminants, counting
times can always be increased to
increase the sensitivity and hence lower
the appropriate acceptance limits. While
the fifty minute counting time in
Standard Method 7500-Rn reflects a
balanced trade-off between time of
analysis (and hence the cost of analysis)
and sensitivity, it can obviously be
adjusted as needed to adjust sensitivity.
For this reason, commenters objected to
the use of acceptance limits (and,
relatedly, PQLs) for radiochemical
contaminants.
EPA agrees that these comments have
merit and has decided to seek comment
on two proposals regarding the use of
acceptance limits and PQLs for radon.
The first proposal, and the preferred
option, is to not use acceptance limits
or PQL for radon, and to adopt the
detection limit as the measure of
sensitivity, as done in the 1976
Radionuclides rule. The existing
definition of the detection limit takes
into account the influence of the various
factors (efficiency, volume, recovery
yield, background, counting time) that
typically vary from sample to sample.
Thus, the detection limit applies to the
circumstances specific to the analysis of
an individual sample and not to an
idealized set of measurement
parameters, as with acceptance limits
and PQLs. The proposed detection limit
is 12 +/- 12 pCi/L, which is based on
the detection limit described in SM
7500-Rn (50 minute counting time, 6
cpm background, 2.7 cpm/dpm
efficiency, and under the energy
window optimization procedure as
described in the method). This detection
limit should be applicable to all three
approved methods.
One of the reasons for setting a
sensitivity standard is to ensure that
laboratories will perform acceptably
well on a routine basis at contaminant
levels near the MCL. Internal quality
control/quality assurance procedures
are of paramount importance. In
addition, Proficiency Tests are
administered by laboratory certifying
authorities to ensure that laboratory
performance is acceptable. Currently,
the-system for administering proficiency
tests and certifying laboratories is in a
state of transition. Up to the recent past,
all primacy entities evaluated laboratory
performance based on EPA's
Performance Evaluation (PE) studies
program, the National Exposure
Research Laboratory (NERL-LV)
Performance Evaluation (PE) Studies
program for radioactivity in drinking
water. Currently, the Proficiency Testing
(PT) program for radionuclides is being
privatized, i.e., operated by an
independent third party provider
accredited by the National Institute of
Standards and Technology (NIST). A
lack of uniformity in state PT
requirements may limit laboratory
availability for a given public water
system to laboratories that use PT
samples approved by the state. It should
be noted that this issue is general and
is not specific to the proposed radon
regulation. Efforts to encourage
uniformity in state PT requirements are
described in more detail in the
laboratory capacity section.
Under the alternative of using the
MDL as the measure of sensitivity,
standard statistical procedures would be
used to ensure that a laboratory has
analyzed PT samples acceptably. Since
the national PT program will still be
overseen by EPA, the exact procedures
for determining acceptable performance
will be developed by EPA and NIST as
the PT program develops. The
respective roles of EPA and NIST in the
PT program and discussed further in the
Laboratory Approval and Certification
section.
The second proposal is to use the
concepts of the acceptance limit and
PQL for radon. Using the standard
relationship that PQLs are equal to 5 to
10 times the MDL yields a PQL for
radon in the range of 60 to 240 pCi/L.
EPA is proposing a PQL of 100 pCi/L
and is seeking comment on this value.
The proposed acceptance limit for a
single sample is ±5 %. The proposed
acceptance limits for triplicate analyses
at the 95th and 99th percent confidence
intervals are ±6 % and ±9 %,
respectively. All of these acceptance
limits are based on the inter-laboratory
studies used for the precision and
accuracy results reported in Table
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59297
VIII.B.3. EPA seeks comments on the
relative merits between the first option
(the preferred option) of using only an
MDL as the measure of sensitivity and
the second option of using a PQL with
prescribed acceptance limits.
TABLE VIII.B.3.—INTER-LABORATORY PERFORMANCE DATA FOR PROPOSED RADON ANALYTICAL METHODS
Method
SM7500-Rn
SM 7500-Rn
Da-Emanation
De-Emanation
ASTM D5072-92
ASTM D5072-92
ASTM D5072-92
Sample
Cone.
pCi/L
111
153
111
153
1 622
16324
66,324
Accuracy
%
101 102
1 no 1 (M
Q7
QE;
94
Repeat-
ability
pCi/L
m
1 R
291V
UQcn
49,190
Reproduc-
ibility
pCi/Ls
210,350
Bias
%
-6.0
Notes: (1) All results are reported in methods citations found in Table VIII.B.1.
(h) Accuracy and Precision of the
Proposed Methods. While SM 7500-Rn
has the best over-all results in precision
and accuracy, the de-emanation method
also shows acceptable performance. The
ASTM method shows similar accuracy
and bias, but much larger errors in
repeatability (operator precision) and
reproducibility (between-lab precision).
Given this inferior demonstration of
precision and the higher concentrations
used In the intra-laboratory studies, it
may be argued that this method should
not be proposed as a drinking water
method. However, EPA maintains that
the method is similar enough in
substance to SM 7500-Rn that it may
serve as an alternate method if the
laboratories use the appropriate quality
control measures, i.e., ensure that the
relative percent difference between
results on duplicate samples is within
the counting uncertainty 95%
confidence interval, where at least 10%
of dally samples are duplicates. This
procedure is described in the 4th
edition of the Manual for the
Certification of Laboratories Analyzing
Drinking Water, Criteria and Procedures
Quality Assurance (EPA 1997). EPA
requests comment on including ASTM
D5072-92 as an alternate test method.
C. Laboratory Approval and
Certification
1. Background
The ultimate effectiveness of the
proposed regulations depends upon the
ability of laboratories to reliably analyze
contaminants at relatively low levels.
The Drinking Water Laboratory
Certification Program is intended to
ensure that approved drinking water
laboratories analyze regulated drinking
water contaminants within acceptable
limits of performance. The Certification
Program is managed through a
cooperative effort between EPA's Office
of Ground Water and Drinking Water
and its Office of Research and
Development. The program stipulates
that laboratories analyzing drinking
water compliance samples must be
certified by U.S. EPA or the State. The
program also requires that certified
laboratories must analyze PT samples,
use approved methods, and States must
also require periodic on-site audits.
External checks of performance to
evaluate a laboratory's ability to analyze
samples for regulated contaminants
within specific limits is one of the
means of judging lab performance and
determining whether to grant
certification. Under a PT program,
laboratories must successfully analyze
PT samples (contaminant
concentrations are unknown to the
laboratory being reviewed) that are
prepared by an organization that is
approved by the primacy entity.
Successful annual participation in the
PT program is prerequisite for a
laboratory to achieve certification and to
remain certified for analyzing drinking
water compliance samples. Achieving
acceptable performance in these studies
of known test samples provides some
indication that the laboratory is
following proper practices.
Unacceptable performance may be
indicative of problems that could affect
the reliability of the compliance
monitoring data.
EPA's previous PE sample program
and the approaches to determine
laboratory performance requirements
are discussed in 63 FR 47097
(September 3, 1998, "1998 methods
update"). In that notice, EPA amended
the regulations to adopt the universal
requirement for laboratories to
successfully analyze a PE sample at
least once each year, addressing the fact
that the Agency has not specified PE test
frequency requirements in its current
drinking water regulations. Though not
specified in the methods update
regulation, PE samples may be provided
by EPA, the State, or by a third party
with the approval of the State or EPA.
Under the developing PT program, NIST
has accredited a list of PT sample
providers, including a radionuclides PT
samples which will apply to radon.
In addition, guidance on minimum
quality assurance requirements,
conditions of laboratory inspections,
and other elements of laboratory
certification requirements for
laboratories conducting compliance
monitoring measurements are detailed
in the 4th edition of the Manual for the
Certification of Laboratories Analyzing
Drinking Water, Criteria and Procedures
Quality Assurance (EPA 1997), which
can be downloaded via the internet at
"http://www.epa.gov/OGWDW/
labindex.html".
2. Laboratory Capacity—Practical
Availability of the Methods
In order to determine the practical
availability of the methods, EPA
considered three major factors. First, the
availability of the major instrumentation
was reviewed. Secondly, several
laboratories performing drinking water
analyses were contacted to determine
their potential capabilities to perform
radon analyses. Lastly, EPA has
reviewed the current status of the
privatized Performance Evaluation
studies program and the on-going
measure to implement a uniform
program, highlighting the potential
impacts on short-term and long-term
laboratory capacity for radon.
3. Laboratory Capacity: Instrumentation
Regarding instrumentation
availability, the major instrumentation
required for LSC is the liquid
scintillation counter. Automated
counters capable of what that method
terms "automatic spectral analysis" are
available from at least a dozen
suppliers. The de-emanation Lucas cell
apparatus is the same apparatus that has
been used for radium analyses for many
years. In light of the wide availability
and the long history of accessibility of
the proper instrumentation, EPA
believes that instrument availability
should not be an issue for radon
analytical methods.
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4. Laboratory Capacity: Survey of
Potential Laboratories
In order to evaluate the availability of
laboratory capacity to perform radon
analyses, EPA contacted the drinking
water certification authorities in the
States of California, Maryland, and
Pennsylvania. These states were chosen
based both on estimated radon
occurrence and the overall status of the
programs. Ultimately, EPA collected
information on the availability and
relative costs of radon analyses for
drinking water from a total of nine
commercial laboratories.
Eight of the nine laboratories that
were contacted do perform radon
analyses. All the laboratories were
certified in one or more states to
perform radiochemical analyses. When
asked what specific methods were used,,
the laboratories responded with either
the technique (liquid scintillation .
counting) or a specific method citation.
EPA Method 913 (which later was
revised to become SM 7500-Rn) was
cited by two of the laboratories. EPA
Method "EERF Appendix B" was cited
by another laboratory. The remaining
laboratories indicated that they
performed liquid scintillation analyses
and could accommodate requests for
methods employing that technique.
When asked about capacity, the
laboratories indicated that they each
perform between 100 and 12,000
analyses per year. The latter figure came
from a laboratory that is currently
involved in a large ground water
monitoring project in the western
United States. The next largest estimate
was 300 samples per year. However,
EPA expects that like any other type of
environmental analysis, given a
regulatory "driver" to perform the
analysis, and given the ability of LSC
analysis to be automated, the laboratory
capacity will develop in a timely
manner.
EPA's 1992 Annual Report on
Radiation Research and Methods
Validation reports the results of a
collaborative study on radon analysis
(EPA 1993) and is another useful source
of information regarding potential radon
laboratory capacity. This study
employed 51 laboratories with the
capability to perform liquid scintillation
analyses. This suggests that at that time
there already existed a substantial
capacity for these analyses.
Further, the liquid scintillation
apparatus is used for other
radiochemical analyses, including
tritium. Information from EPA regarding
the performance evaluation program for
tritium analyses suggests that there are
approximately 100-200 laboratories
with the necessary equipment. Much of
the capacity for tritium analyses could
also be used for radon (EPA 1997). As
of September 1997, 136 of 171
participating laboratories achieved
acceptable results for tritium. While the
total number of participants and the
number achieving acceptable results
vary between studies, the data indicate
that there is a substantial capability for
liquid scintillation analysis nationwide.
5. Laboratory Capacity: Laboratory
Certification and Performance
Evaluation Studies
The availability of laboratories is also
dependent on laboratory certification
efforts in the individual states with
regulatory authority for their drinking
water programs. Until June of 1999, a
major component of many of these
certification programs was their
continued participation in the current
EPA Water Supply WS performance
evaluation (PE) program, which
included radiochemistry PE studies.
Due to resource limitations, EPA has
recently privatized EPA's PE programs,
including the Water Supply studies.
EPA has addressed this topic in public
stakeholders meetings and in some
recent publications, including Federal
Register notices and its June 1997
"Labcert Bulletin", which can be
downloaded from the Internet at "http:/
/www.epa.gov/OGWDW/labcertS.html".
The decision to privatize the PE studies
programs was announced in the Federal
Register on June 12, 1997 (62 FR 32112).
This notice indicated that in the future
the National Institute of Standards and
Technology (NIST) would develop
standards for private sector PT sample
providers and would evaluate and
accredit these providers, while the
actual development and manufacture of
PT samples would fall to the private
sector. Further information regarding
the respective roles of EPA and NIST in
the privatized PT program can be
downloaded from NIST's homepage at
" http: //ts. nist .go v/ts/htdocs/210/
210.htm". EPA believes that this
program will ensure the continued
viability of the existing PT programs,
while maintaining government
oversight.
This externalized proficiency testing .
program is in the process of becoming
operational. Under the externalized PT
program:
• EPA issues standards for the
operation of the program,
• NIST administers a program to
accredit PT sample providers,
• • Non-EPA PT sample providers
develop and manufacture PT sample
materials and conduct PT studies,
• • Environmental laboratories
purchase PT samples directly from PT
Sample Providers (approved by NIST or
the State), and
• Certifying authorities certify
environmental laboratories performing
sample analyses in support of the
various water programs administered by
the States and EPA under the Safe
Drinking Water Act.
NIST is in the process of approving a
provider for PT samples for
radionuclides, including radon. States
also have the option of approving their
own PT sample providers. At this time,
it is difficult to speculate to what degree
this externalization of the PT program
will affect short-term and long-term
laboratory capacity for radon. EPA
recognizes that initial implementation
problems may arise because of the
potential for near-term limited
availability of radon PT samples. EPA
also recognizes that insufficient
laboratory capacity may lead to a short-
term increase in analytical costs. In the
absence of definitive information
regarding the future PT program, EPA
solicits public comment on this matter.
6. Efforts To Ensure a Uniform
Proficiency Testing Program: NELAC
The National Environmental
Laboratory Accreditation Conference
(NELAC) is also evaluating the issues
surrounding privatization of the SD WA
PT program through its proficiency
testing committee. NELAC serves as a
voluntary national standards-setting
body for environmental laboratory
accreditation, and includes members
from both state and Federal regulatory
and non-regulatory programs having
environmental laboratory oversight,
certification, or accreditation functions.
One of the goals for the re-designed
SDWA PT program is to be consistent
with NELAC's recommendations.
The members of NELAC meet bi-
annually to develop consensus
standards through its committee
structure. These consensus standards
are adopted by participants for use in
their own programs in pursuit of a
uniform national laboratory
accreditation program in which
environmental testing laboratories will
be able to receive one annual
accreditation that is accepted
nationwide. As part of its accreditation
program, NELAC is developing
standards for a proficiency testing
program that addresses all fields of
testing, including drinking water.
Recent meetings of the Proficiency
Testing Committee of NELAC have
reviewed several important issues,
including State selection of PT sample
providers and reciprocity between
States.
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These issues are described in more
detail elsewhere (NELAC 1999a). The
NELAC Proficiency Testing Committee
is currently drafting requirements for
radiochemical proficiency testing under
SDWA. The June 15, 1999 draft (NELAC
1999b) of its radiochemical proficiency
testing requirements describes
radiochemical PT sample designs,
acceptance limits, and other
Information.
The intent of the NELAC standards
setting process is to ensure that the
needs of EPA and state regulatory
programs are satisfied in the context of
a uniform national laboratory
accreditation program. EPA recognizes
that cooperating with NELAC is an
important part of the re-design of the
Proficiency Testing (PT) program for
drinking water, since NELAC provides a
means for states, environmental testing
laboratories, and PT study providers to
have direct input into the process. It is
hoped that this mutual effort will
minimize the potential disruption in the
process of moving from the old EPA PE
program towards the new privatized PT
program. EPA shares NELAC's goal of
encouraging uniformity in standards
between primacy States regarding
laboratory proficiency testing and
accreditation.
7. Laboratory Capacity: Holding Time
The short holding time for radon, 4
days in Method 7500-Rn, presents
concerns relative to the practical
availability of laboratory capacity as
well. The 4-day holding time was also
the focus of a number of comments that
EPA received in response to the 1991
proposed rule. Many commenters were
concerned that if a local laboratory is
not available, the only alternative will
be to send the samples by overnight
delivery to a laboratory elsewhere.
However, this situation is not unique to
the analysis of radon. As evidenced
during the data gathering pursuant to
the Disinfection By-Products
Information Collection Rule (DBPICR),
several large commercial laboratories
already account for a sizable share of the
market for SDWA analyses for non-
radon parameters, including organics,
for which the holding times are often 7
days. Given that a day would be
required for shipping the samples, only
three days would remain for the
laboratory to perform the radon analysis
(the day on which the sample is
collected being "day zero"). Some
commenters argued that for a large
commercial laboratory serving the water
utilities, this short holding time will
make it difficult if not impossible to
perform the necessary analyses within
the holding time. However, through
common sense scheduling efforts
between the utility and the laboratory,
such as not collecting samples on
Thursdays and Fridays, the holding
time issue should be able to be
accommodated in light of the ability of
the LSC method to be highly automated.
D. Performance-Based Measurement
System (PBMS)
On October 6, 1997, EPA published a
Notice of the Agency's intent to
implement a Performance Based
Measurement System (PBMS) in all of
its programs to the extent feasible (62
FR 52098). EPA is currently determining
how to adopt PBMS in its drinking
water program, but has not yet made
final decisions. When PBMS is adopted
in the drinking water program, its
intended purpose will be to increase
flexibility in laboratories in selecting
suitable analytical methods for
compliance monitoring, significantly
reducing the need for prior EPA
approval of drinking water analytical
methods. Under PBMS, EPA will
modify the regulations that require
exclusive use of Agency-approved
methods for compliance monitoring of
regulated contaminants in drinking
water regulatory programs. EPA will
probably specify "performance
standards" for methods, which the
Agency would derive from the existing
approved methods and supporting
documentation. A laboratory would
then be free to use any method or
method variant for compliance
monitoring that performed acceptably
according to these criteria. EPA is
currently evaluating which relevant
performance characteristics should be
specified to ensure adequate data
quality for drinking water compliance
purposes. After PBMS is implemented,
EPA may continue to approve and
publish compliance methods for
laboratories that choose not to use
PBMS. After EPA makes final
determinations to implement PBMS in
programs under the Safe Drinking Water
Act, EPA would then provide specific
instruction on the specified
performance criteria and how these
criteria would be used by laboratories
for radon compliance monitoring.
E. Proposed Monitoring and Compliance
Requirements for Radon
1. Background
The monitoring regulation for radon
proposed in 1991 by EPA required that
groundwater systems monitor for radon
at each entry point to the distribution
system quarterly for one year initially.
Monitoring could be reduced to one
sample annually per entry point to the
distribution system if the average of all
first quarterly samples was below the
MCL. States could allow systems to
reduce monitoring to once every three
years if the system demonstrated that
results of all previous samples collected
were below the MCL. The proposal also
allowed States to grant waivers to
groundwater systems to reduce the
frequency of monitoring, up to once
every 9 years, if States determined that
radon levels in drinking water were
consistently and reliably below the
MCL. Comments made in response to
the proposed monitoring requirements
for radon were mainly concerned that
the proposed monitoring requirements
including number of samples and the
frequency of monitoring did not
adequately take into account the effect
of seasonal variations in radon levels on
determining compliance. Other
commenters felt that sampling at the
entry point of the distribution system
was not representative of exposure to
radon, and they suggested that sampling
for radon should be done at the point of
use.
Since the 1991 proposal EPA has
obtained additional information from
States, the waterworks industry and
academia on the occurrence of radon,
including data on the temporal
variability of radon. Utilizing this
additional data, the Agency performed
extensive statistical analyses to predict
how temporal, analytical variations and
variations between individual wells
may affect exposure to radon. The
results of these analyses are described in
detail In the report "Methods,
Occurrence and Monitoring Document
for Radon" in the docket for this rule
(USEPA 1999g). As a result of the new
information available, EPA was able to
refine the requirements for monitoring
and address the concerns expressed by
the commenters on the 1991 proposal.
The proposed monitoring
requirements for radon are consistent
with the monitoring requirements for
regulated drinking water contaminants,
as described in the Standardized
Monitoring Framework (SMF)
promulgated by EPA under the Phase II
Rule of the National Primary Drinking
Water Regulations (NPDWR) and
revised under Phases IIB and V. The
goal of the SMF is to streamline the
drinking water monitoring requirements
by standardizing them within
contaminant groups and by
synchronizing monitoring schedules
across contaminant groups. A summary
of monitoring requirements in this
proposal, the SMF and the 1991
proposal are provided in Table VIII.E.l.
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TABLE VIII.E.1.—COMPARISON OF MONITORING REQUIREMENTS
Monitoring requirements for radon
1991 Proposal
1999 Proposal—MCL/AMCL
SMF for IOCS in groundwater
Initial Monitoring Requirements
Four consecutive quarters of monitoring at
each entry point for one year. Initial moni-
toring was proposed to have been com-
pleted by January 1, 1999.
Four consecutive quarters of monitoring at
each entry point. Initial monitoring must
begin by three years from date of publica-
tion of the final rule in FEDERAL REGISTER of
4.5 years from date of publication of the
final rule in FEDERAL REGISTER (depending
on effective date applicable to the State).
Four consecutive quarters of monitoring at
each entry point for sampling points initially
exceeding MCL.
Routine Monitoring Requirements
One sample annually if average from four con-
secutive quarterly samples taken initially is
less than MCL.
1991 Proposal
One sample annually if average from four
consecutive quarterly samples is less than
MCL/AMCL, and at the discretion of State.
1999 Proposal— MCL
One sample at each sample point during the
initial 3 year compliance period for ground-
water systems for sampling points below
MCL.
SMF for lOCs in Groundwater
Reduced Monitoring Requirements
State may allow groundwater systems to re-
duce the frequency of monitoring to once
every three years provided that they have
monitored quarterly in the initial year and
completed annual testing in the second and
third year of the first compliance period.
Groundwater systems must demonstrate that
all previous analytical samples were less
than the MCL.
State may allow CWS using groundwater to
reduce monitoring frequency to:.
Once every three years if average from four
consecutive quarterly samples is less than
Vz the MCL/AMCL, provided no samples ex-
ceed the MCL7AMCL. and if the system is
determined by State to be "reliably and con-
sistently below MCL/AMCL ".
State may allow groundwater systems to re-
duce monitoring frequency to:
Once every three years if samples subse-
quently detects less than MCL and deter-
mined by State to be "reliably and consist-
ently below MCL."
Monitoring Requirements for Radon
1991 Proposal
1999,Proposal—MCL/AMCL
SMF for lOCs in Groundwater
Increased Monitoring Requirements
Systems monitoring annually or once per three
year compliance period exceed the radon
MCL in a single sample would be required to
revert to quarterly monitoring until the aver-
age of 4 consecutive samples is less than
the MCL. Groundwater systems with
unconnected wells would be required to con-
duct increased monitoring only at those wells
exceeding the MCL.
The State may require more frequent moni-
toring than specified.
Systems may apply to the State to conduct
more frequent monitoring than the minimum
monitoring frequencies specified.
Systems monitoring annually would be re-
quired to increase monitoring if the MCL/
AMCL for radon is exceeded in a single
sample, the system would be required to re-
vert to quarterly monitoring until the average
of 4 consecutive samples is less than the
MCL/AMCL.
Systems monitoring once every three years
would be required to monitor annually if the
radon level is less than MCL/AMCL but
above Vz MCL/AMCL in a single sample.
Systems may revert to monitoring once per
three years if the average of the initial and
three consecutive annual samples is lees
than Va MCL/AMCL.
CWS using groundwater with un-connected
- wells would be required to conduct in-
creased monitoring only at those well which
are affected.
If the MCL is exceeded in a single sample, the
system required to begin sampling quarterly
until State determines that it is "reliably and
consistently" below MCL.
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TABLE VIII.E.1.—COMPARISON OF MONITORING REQUIREMENTS—Continued
Monitoring requirements for radon
1991 Proposal
1999 Proposal—MCL/AMCL
SMF for lOCs in groundwater
Monitoring Requirements for Radon
1991 Proposal
1999 Proposal—MCL
SMF for lOCs in Groundwater
Confirmation Samples
Where the results of sampling indicate an
excecdence of the maximum contaminant
level, the State may require that one addi-
tional sample be collected as soon as pos-
sible after the initial sample was taken [but
not to exceed two weeks] at the same sam-
pling point. The results of the of the initial
sample and the confirmation sample shall be
averaged and the resulting average shall be
used to determine compliance.
Systems may collect confirmation samples as
specified by the State. The average of the
initial sample and any confirmation samples
will be used to determine compliance.
Where the results sampling indicate an
exceedence of the maximum contaminant
level, the State may require that one addi-
tional sample be collected as soon as pos-
sible after the initial sample was taken [but
not to exceed two weeks] at the same sam-
pling point. The results of the initial sample
and the confirmation sample shall be aver-
aged and the resulting average shall be
used to determine compliance.
Grandfathering of Data
If monitoring data collected after January 1,
1985 are generally consistent with the re-
quirements specified in the regulation, than
the State may allow the systems to use
those data to satisfy the monitoring require-
ments for the initial compliance period.
If monitoring data collected after proposal of
the rule are consistent with the require-
ments specified in the regulation, then the
State may allow the systems to use those
data to satisfy the monitoring requirements
for the initial compliance period.
States may allow previous sampling data to
satisfy the initial sampling requirements pro-
vided the data were collected after January
1, 1990.
Monitoring Requirements for Radon
1991 Proposal
1999 Proposal—MCL
SMF for lOCs in Groundwater
Waivers
State may grant waiver to groundwater sys-
tems to reduce the frequency of monitoring,
up to nine years. If State determines that
radon levels In drinking water are "reliably
and consistently" below the MCL.
The State may grant a monitoring waiver to
systems to reduce the frequency of moni-
toring to up to one sample every nine years
based on previous analytical results, geo-
logical characteristics of source water aqui-
fer and if a State determines that radon lev-
els in drinking water are "reliably and con-
sistently" below the MCL/AMCL.
Analytical results of all previous samples
taken must be below 1/2 the MCL/AMCL.
The State may grant waiver to groundwater
systems after conducting vulnerability as-
sessment to reduce the frequency of moni-
toring, up to nine years, if State determines
that radon levels in drinking water are "reli-
ably and consistently" below the MCL.
System must have three previous samples.
Analytical results of all previous samples
taken must be below MCL.
In developing the proposed
compliance monitoring requirements for
radon, EPA considered:
(1) The likely source of contamination
in drinking water;
(2) The differences between ground
water and surface water systems;
(3) The collection of samples which
are representative of consumer
exposure;
(4) Sample collection and analytical
methods;
(5) The use of appropriate historical
data to identify vulnerable systems and
to specify monitoring requirements for
individual systems;
(6) The analytical, temporal and intra-
system variance of radon levels;
(7) The use of appropriate historical
data and statistical analysis to establish
reduced monitoring requirements for
individual systems; and
(8) The need to provide flexibility to
the States to tailor monitoring
requirements to site-specific conditions
by allowing them to:
—Grant waivers to systems to reduce
monitoring frequency, provided
certain conditions are met.
—Require confirmation samples for any
sample exceeding the MCL/AMCL.
—Allow the use of previous sampling
data to satisfy initial sampling
requirements.
—Increase monitoring frequency.
—Decrease monitoring frequency.
2. Monitoring for Surface Water Systems
CWSs relying exclusively on surface
water as their water source will not be
required to sample for radon. Systems
that rely in part on ground water would
be considered groundwater systems for
purposes of radon monitoring. Systems
that use ground water to supplement
surface water during low-flow periods
will be required to monitor for radon.
Ground water under the influence of
surface water would be considered
ground water for this regulation.
3. Sampling, Monitoring Schedule and
Initial Compliance for CWS Using
Groundwater
EPA is retaining the quarterly
monitoring requirement for radon as
proposed initially in the 1991 proposal
to account for variations such as
sampling, analytical and temporal
variability in radon levels. Results of
analysis of data obtained since 1991,
estimating contributions of individual
sources of variability to overall variance
in the radon data sets evaluated,
indicated that sampling and analytical
variance contributes less than 1 percent
to the overall variance. Temporal
variability within single wells accounts
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for between 13 and 18 percent of the
variance in the data sets evaluated, and
a similar proportion (12-17 percent)
accounts for variation in radon levels
among wells within systems. (USEPA
1999g)
The Agency performed additional
analyses to determine whether the
requirement of initial quarterly
monitoring for radon was adequate to
account for seasonal variations in radon
levels and to identify non-compliance
with the MCL/AMCL. Results of
analysis based on radon levels modeled
for radon distribution for ground water
sources (USEPA 1999g) and systems
(USEPA 1998a) in the U.S. show that
the average of the first four quarterly
samples provides a good indication of
the probability that the long-term
average radon level in a given source
would exceed an MCL or AMCL. Tables
VIII.E.2 and VIII.E.3 show the
probability of the long-term average
radon level exceeding the MCL and
AMCL at various averages obtained from
the first four quarterly samples from a
source.
TABLE VIII.E.2.—THE RELATIONSHIP
BETWEEN THE FIRST-YEAR AVERAGE
RADON LEVEL AND THE PROBABILITY
OF THE LONG-TERM RADON AVER-
AGE RADON LEVELS EXCEEDING THE
MCL
TABLE VIII.E.3.—THE RELATIONSHIP
BETWEEN THE FIRST-YEAR AVERAGE
RADON LEVEL AND THE PROBABILITY
OF THE LONG-TERM RADON AVER-
AGE RADON LEVELS EXCEEDING THE
AMCL—Continued
If the average of the first
four quarterly samples from
a source is
Less than 50 pCi/L
Between 50 and 100 pCi/L
Between 100 and 150 pCi/
L.
Between 150 and 200 pCi/
L.
Between 200 and 300 pCi/
L.
Then the prob-
ability that the
long-term aver-
age radon level
in that source
exceeds 300
pCi/L is
0 percent.
0.5 percent.
0.4 percent.
7.2 percent.
26.8 percent.
TABLE VIII.E.3.—THE RELATIONSHIP
BETWEEN THE FIRST-YEAR AVERAGE
RADON LEVEL AND THE PROBABILITY
OF THE LONG-TERM RADON AVER-
AGE RADON LEVELS EXCEEDING THE
AMCL
If the average of the first
four quarterly samples from
a source is
Less than 2,000 pCi/L
Then the prob-
ability that the
long-term aver-
age radon level
in that source
exceeds 4000
pCi/L is
If the average of the first
four quarterly samples from
a source is
Between 2,000 and 2,500
pCi/L.
Between 2,500 and 3,000
pCi/L.
Between 3,000 and 4,000
pCi/L.
Then the prob-
ability that the
long-term aver-
age radon level
in that source
exceeds 4000
pCi/L is
9.9 percent.
15.1 percent.
32.9 percent.
Less than 0.1
percent.
The Agency proposes that systems
relying wholly or in part on ground
water will be required to initially
sample quarterly for radon for one year
at each well or entry point to the
distribution system. All samples will be
required to be of finished water, as it
enters the distribution system after any
treatment and storage. If the average of
the four quarterly samples at each well
is below the MCL/AMCL, monitoring
may be reduced to once a year at State
discretion. Systems may be required to
continue monitoring quarterly in
instances where the average of the
quarterly samples at each well is below
but close to the MCL/AMCL. The reason
for this is that in such cases, there is a
good chance for the long-term average
radon level to exceed the MCL/AMCL.
Systems already on-line must begin
initial monitoring for compliance with
the MCL/AMCL by the compliance
dates specified in the rule (i.e., 3 years
after the date of promulgation or 4.5
years after the date of promulgation).
Monitoring requirements for new
sources will be determined by the State.
The compliance dates are discussed in
detail in Section VILE, Compliance
Dates.
The Agency is retaining the
requirement as proposed in 1991 to
sample at the entry point to the
distribution system. Sampling at the
entry point allows the system to account
for radon decay during storage and
removal during the treatment process.
The reason for not allowing sampling at
the point of use is that this approach
would not take into account higher
exposure levels that may be
encountered at locations upstream from
the sampling site. In addition, sampling
at the entry point will make it easier to
identify and isolate possible
contaminant sources within the system.
The sample collection sites at each entry
point to the distribution system and the
monitoring schedule requiring sampling
for four consecutive quarters proposed
herein is consistent with the SMF. This
approach streamlines monitoring since
the same sampling points can be used
for the collection of samples for other
source-related contaminants.
EPA specifically requests comments
on the following aspects of the proposed
monitoring requirements:
• The appropriateness of the
proposed initial monitoring period.
• The availability and capabilities of
laboratories to analyze radon samples
collected during the initial compliance
period. The Agency recognizes that
short-term implementation problems
may arise to meet the initial monitoring
deadline because of the potential
limited availability of radon
performance evaluation (PE) samples
used to evaluate and certify laboratories.
• The appropriateness of the
proposed number and frequency of
samples required to monitor for radon.
• The designation of sampling
locations at the entry point to the
distribution system which is located
after any treatment and storage.
Comments are also solicited on the
definition of sampling points that are
representative of consumer exposure.
• Designating sampling locations and
frequencies that permit simultaneous
monitoring for all regulated
contaminants, whenever possible and
advantageous. The proposed sampling
locations would be such that the same
sampling locations could be used for the
collection of samples for other source-
related contaminants such as the
volatile organic chemicals and inorganic
chemicals, which would simplify
sample collection efforts.
EPA also solicits comments on
whether the monitoring requirements
should include additional monitoring
for radon as a source of consumer
exposure from the distribution system.
Results of investigations in Iowa
indicate that in some instances, pipe
scale deposited in the distribution
system can be a source of exposure to
radon. Community ground water
systems could be required to collect an
additional sample from the distribution
system during the initial year of
monitoring, at the same time the entry
point sample is collected, and continue
to collect samples from the distribution
system annually if it is shown that
exceedence of the MCL/AMCL is caused
by the release of radon from deposited
scale in the interior of the distribution
system. Results obtained from
distribution samples could provide
information on the extent and frequency
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59303
of occurrence of radon originating from
distribution systems.
4. Increased/Decreased Monitoring
Requirements
Initial compliance with the MCL/
AMCL will be determined based on an
average of four quarterly samples taken
at individual sampling points in the
initial year of monitoring. Systems with
averages exceeding the MCL/AMCL at
any sampling point will be deemed to
be out of compliance. Systems in a non-
MMM State exceeding the MCL will
have the option to develop and
implement a local MMM program in
accordance with the timeframe
discussed in Section VILE, Compliance
Dates without receiving a MCL
violation.
Systems exceeding the MCL/AMCL
will be required to monitor quarterly
until the average of four consecutive
samples is less than the MCL/AMCL.
Systems will then be allowed to collect
one sample annually if the average from
four consecutive quarterly samples is
less than the MCL/AMCL and if the
State determines that the system is
reliably and consistently below the
MCL/AMCL.
Systems will be allowed to reduce
monitoring frequency to once every
three years (one sample per compliance
period) per well or sampling point, if
the average from four consecutive
quarterly samples is less than Vz the
MCL/AMCL and the State determines
that the system is reliably and
consistently below the MCL/AMCL. As
shown in Tables VIII.E.2 and VIII.E.3,
EPA believes that there is sufficient
margin of safety to allow for this since
there is a small probability that long
term average radon levels will exceed
the MCL/AMCL.
Systems monitoring annually that
exceed the radon MCL/AMCL in a
single sample will be required to revert
to quarterly monitoring until the average
of four consecutive samples is less than
the MCL/AMCL. Community ground
water systems with unconnected wells
will be required to conduct increased
monitoring only at those wells
exceeding the MCL/AMCL. Compliance
will be based on the average of the
initial sample and three consecutive
quarterly samples.
Systems monitoring once per
compliance period or less frequently
which exceed l/z the MCL/AMCL (but
do not exceed the MCL/AMCL) in a
single sample would be required to
revert to annual monitoring. Systems
may revert to monitoring once every
three years if the average of the initial
and three consecutive annual samples is
less than >/z the MCL/AMCL.
Community ground water systems with
unconnected wells will be required to
conduct increased monitoring only at
those wells exceeding the MCL/AMCL.
States may grant a monitoring waiver
reducing monitoring frequency to once
every nine years (once per compliance
cycle) provided the system
demonstrates that it is unlikely that
radon levels in drinking water will
occur above the MCL/AMCL. In granting
the monitoring waiver, the State must
take into consideration factors such as
the geological area where the water
source is located, and previous
analytical results which demonstrate
that radon levels do not occur above the
MCL/AMCL. The monitoring waiver
will be granted for up to a nine year
period. (Given that all previous samples
are less than Vz the MCL/AMCL, then it
is highly unlikely that the long-term
average radon levels would exceed the
MCL/AMCL.)
If the analytical results from any
sampling point are found to exceed the
MCL/AMCL (in the case of routine
monitoring) or Vz the MCL/AMCL (in
the case of reduced monitoring), the
State may require the system to collect
a confirmation sample(s). The results of
the initial sample and the confirmation
sample (s) shall be averaged and the
resulting average shall be used to
determine compliance.
EPA specifically requests comments
on the following aspects of the proposed
monitoring requirements:
• Allowing systems at State
discretion, to reduce monitoring
frequencies as long as the system
demonstrates that its radon levels are
maintained below the MCL/AMCL. For
example, all community ground water
systems would be required to collect
one sample from each entry point to the
distribution system (located after any
treatment and storage) quarterly at first
and annually after compliance is
established. MCL/AMCL exceedence
would trigger reverting to quarterly
sampling until compliance with the
MCL/AMCL is reestablished.
Compliance is reestablished when the
average of four consecutive quarterly
samples is below the MCL/AMCL.
• Allowing States to reduce
monitoring requirements to not less
than once every three years if the
average radon levels from four
consecutive quarterly samples is less
than Vz the MCL/AMCL, and the State
determines that the radon levels in the
drinking water are reliably and
consistently below Vz the MCL/AMCL.
A single sample exceeding Vz the MCL/
AMCL would trigger reverting to
sampling annually. Comments are
solicited on the criteria allowing the
utility to revert to monitoring once
every three years if the average of the
initial and three consecutive annual
samples is less than Vz the MCL/AMCL.
• Factors affecting State discretion to
grant waivers. In addition, the Agency
solicits comments on the advisability of
reducing the monitoring frequency up to
nine years between samples. Comments
are solicited on the requirement that all
previous samples (that might be used to
identify systems which are very
unlikely to exceed the MCL/AMCL)
must be below Vz the MCL/AMCL in
order for a system to qualify for a
waiver.
• Allowing States to require the
collection of confirmation samples to
verify initial sample results as specified
by the State, and to use the average of
the initial sample and the confirmation
samples to determine compliance.
5. Grandfathering of Data
At a State's discretion, sampling data
collected since the proposal could be
used to satisfy the initial sampling
requirements for radon, provided that
the system has conducted a monitoring
program and used analytical methods
that meet proposal requirements. The
Agency wants to provide water
suppliers with the opportunity to
synchronize their radon monitoring
program with monitoring for other
contaminants and to get an early start on
their monitoring program if they wish to
do so.
The Agency solicits comments on the
advisability of allowing the use of
monitoring data obtained since the
proposal to satisfy the initial monitoring
requirements.
IX. State Implementation
This section describes the regulations
and other procedures and policies States
have to adopt, or have in place, to
implement today's proposed rule. States
must continue to meet all other
conditions of primacy in 40 CFR part
142.
Section 1413 of the SDWA establishes
requirements that a State must meet to
obtain or maintain primacy enforcement
responsibility (primacy) for its public
water systems. These include: (1)
Adopting drinking water regulations
that are no less stringent than Federal
NPDWRs in effect under Section 1412(b)
of the Act; (2) adopting and
implementing adequate procedures for
enforcement; (3) keeping records and
making reports available on activities
that EPA requires by regulation; (4)
issuing variances and exemptions (if
allowed by the State) under conditions
no less stringent than allowed by
Sections 1415 and 1416; (5) adopting
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and being capable of implementing an
adequate plan for the provision of safe
drinking water under emergency
situations; and (6) adopting authority for
administrative penalties.
40 CFR part 142 sets out the specific
program implementation requirements
for States to obtain primacy for the
public water supply supervision (PWSS)
program, as authorized under SDWA
1413 of the Act. In addition to meeting
the basic primacy requirements, States
may be required to adopt special
primacy provisions pertaining to a
specific regulation. States are required
by 40 CFR 142.12 to include these
regulation-specific provisions in an
application for approval of their
program revisions. To maintain primacy
for the PWS program and to be eligible
for interim primacy enforcement
authority for future regulations, States
must adopt today's rule, when final,
along with the special primacy
requirements discussed next. Interim
primacy enforcement authority allows
States to implement and enforce
drinking water regulations once State
regulations are effective and the State
has submitted a complete and final
primacy revision application. Under
interim primacy enforcement authority.
States are effectively considered to have
primacy during the period that EPA is
reviewing their primacy revision
application.
A. Special State Primacy Requirements
In addition to adopting drinking water
regulations at least as stringent as the
regulations described in the previous
sections, EPA requires that States adopt
certain additional provisions related to
this regulation, in order to have their
drinking water program revision
application approved by EPA. States
have two options when implementing
this rule. States may adopt the AMCL
and implement a State-wide MMM
program plan or States may adopt the
MCL. If a State chooses to adopt the
MCL, CWSs in that State have the
option to develop and implement a
State-approved local MMM program
plan and comply with the AMCL.
To ensure that the State program
includes all the elements necessary for
a complete enforcement program, EPA
is proposing that 40 CFR part 142 be
amended to require the following in
order to obtain primacy for this rule:
(1) Adoption of the promulgated
Radon Rule, and
(2) One of the following, depending
on which regulatory option the State
chooses to adopt:
(a) If a State chooses to develop and
implement a State-wide MMM program
plan and adopt the AMCL, the primacy
application must contain a copy of the
State-wide MMM program plan meeting
the four criteria in 40 CFR Part 141
Subpart R and the following: a
description of how the State will make
resources available for implementation
of the State-wide MMM program plan,
and 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
MMM program plan, including the level
of resources that will be made available
for implementation and coordination
between interagency programs (i.e.,
indoor air and drinking water
programs).
(b) If a State chooses to adopt the
MCL, the primacy application must
contain a description of how the State
will implement a program to approve
local CWS MMM program plans
prepared to meet the criteria outlined in
40 CFR Part 141 Subpart R. In addition,
the primacy application must contain a
description of how the State will ensure
local CWS MMM program plans are
implemented and the extent and nature
of coordination between interagency
programs (i.e., indoor radon and
drinking water programs) on
development and implementation of the
MMM program, including the level of
resources that will be made available for
implementation and coordination
between interagency programs (i.e.,
indoor air and drinking water
programs), as well as, a description of
the reporting and record keeping
requirements for the CWSs.
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)(l) 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 States notify
CWSs of their decision to adopt the
MCL or AMCL at the time they submit
their primacy application package to
EPA (24 months'after publication of the
final rule). If a State adopts the MCL,
CWSs choosing to implement a local
CWS MMM program and comply with
the AMCL will be required,to have
completed initial monitoring, notify the
State of their intention, and begin
developing a plan 4 years after the rule
is final. EPA is particularly concerned
that these CWSs have sufficient time to
develop MMM program plans with local
input arid allow for State approval.
Therefore, it is EPA's expectation that
States will be submitting complete and
final primacy revision applications by
24 months from the date of publication
of the final rule in Federal Register. In
reviewing any State requests for
extensions of time in submitting
primacy revision applications, EPA will
consider whether sufficient time will be
provided to CWSs to develop and get
State approval of their local MMM
program plans prior to implementation.
B. State Record Keeping Requirements
Today's rule does not include changes
to the existing recordkeeping provisions
required by 40 CFR 142.14. MMM
record keeping requirements will be
addressed in each State's primacy
revision application submission to meet
the special primacy requirements for
radon (40 CFR 142.16).
C. State Reporting Requirements
Currently States must report to EPA
information under 40 CFR 142.15
regarding violations, variances and
exemptions, enforcement actions and
general operations of State public water
supply programs.
In accordance with the Safe Drinking
Water Act (SDWA), EPA is to review
State MMM programs at least every five
years. For the purposes of this review,
the States with EPA-approved MMM
program plans shall provide written
reports to EPA in the second and fourth
years between initial implementation of
the MMM program and the first 5-year
review period, and in the second and
fourth years of every subsequent 5-year
review period. EPA will review these
programs to determine whether they
continue to be expected to achieve risk
reduction of indoor radon using the
information provided in the two
biennial reports. EPA requests comment
on this approach. These reports are
required to include the following
information:
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59305
• A quantitative assessment of
progress towards meeting the required
goals described in Section VI. A.,
including the number or rate of existing
homes mitigated and the number or rate
of new homes built radon-resistant since
implementation of the States' MMM
program: and
• A description of accomplishments
and activities that implement the
program strategies outlined in the
implementation plan and in the two
required areas of promoting increased
testing and mitigation of existing homes
and promoting increased use of radon-
resistant techniques in construction of
new homes.
• If goals were defined as rates, the
State must also provide an estimate of
the number of mitigations and radon-
resistant new homes represented by the
reported rate increase for the two-year
period,
• If the MMM program plan includes
goals for promoting public awareness of
the health effects of indoor radon,
testing of homes by the public; testing
and mitigation of existing schools; and
construction of new public schools to be
radon-resistant, the report is also
required to include information on
results and accomplishments in these
areas,
EPA will use this information in
discussions and consultations with the
State during the five-year review to
evaluate program progress and to
consider what modifications or
adjustments in approach may be
needed. EPA envisions this review
process will be one of consultation and
collaboration between EPA and the
States to evaluate the success of the
program in achieving the radon risk
reduction goals outlined in the
approved programs. If EPA determines
that a MMM program in not achieving
progress towards its goals, EPA and the
State shall collaborate to develop
modifications and adjustments to the
program to be implemented over the
five year period following the review.
EPA will prepare a summary of the
outcome of the program evaluation and
the proposed modification and
adjustments, if any, to be made by the
State.
States that submit a letter to the
Administrator by 90 days after
publication of the final rule committing
to develop an MMM program plan, must
submit their first 2-year report by 6.5
years from publication of the final rule.
For States not submitting the 90-day
letter, but choosing subsequently to
submit an MMM program plan and
adopt the AMCL. the first 2-year report
must be submitted to EPA by 5 years
from publication of the final rule. States
shall make available to the public each
of these two-year reports, as well as the
EPA summaries of the five-year reviews
of a State's MMM program, within 90
days of completion of the reports and
the review.
In primacy States without a State-
wide MMM program, the States shall
provide a report to EPA every five-years
on the status and progress of CWS
MMM programs towards meeting their
goals. The first of such reports would be
due 5 years after CWSs begin
implementing a local MMM program
which is 5.5 years from publication of
the final rule.
D. Variances and Exemptions
Section 1415 of the SDWA authorizes
the State to issue variances from
NPDWRs (the term "State" is used in
this preamble to mean the State agency
with primary enforcement
responsibility, or "primacy," for the
public water supply system program or
EPA if the State does not have primacy).
The State may issue a variance under
Section 1415 (a) if it determines that a
system cannot comply with an MCL due
to the characteristics of its source water,
and on condition that the system install
BAT. Under Section 1415(a), EPA must
propose and promulgate its finding
identifying the best available
technology, treatment techniques, or
other means available for each
contaminant, for purposes of Section
1415 variances, at the same time that it
proposes and promulgates a maximum
contaminant level for such contaminant.
EPA's finding of BAT, treatment
techniques, or other means for purposes
of issuing variances may vary,
depending upon the number of persons
served by the system or for other
physical conditions related to
engineering feasibility and costs of
complying with MCLs, as considered
appropriate by the EPA. The State may
not issue a variance to a system until it
determines among other things that the
variance would not pose an
unreasonable risk to health (URTH).
EPA has developed draft guidance,
"Guidance in Developing Health
Criteria for Determining Unreasonable
Risks to Health" (USEPA 1990) to assist
States in determining when an
unreasonable risk to health exists. EPA
expects to issue final guidance for
determining when URTH levels exist
later this year. When a State grants a
variance, it must at the same time
prescribe a schedule for (1) compliance
with the NPDWR and (2)
implementation of such additional
control measures as the State may
require.
Under Section 1416(a), the State may
exempt a public water system from any
MCL and/or treatment technique
requirement if it finds that (1) due to
compelling factors (which may include
economic factors), the system is unable
to comply or develop an alternative
supply, (2) the system was in operation
on the effective date of the MCL or
treatment technique requirement, or, for
a newer system, that no reasonable
alternative source of drinking water is
available to that system, (3) the
exemption will not result in an
.unreasonable risk to health, and (4)
management or restructuring changes
cannot be made that would result in
compliance with this rule. Under
Section 1416(b), at the same time it
grants an exemption the State is to
prescribe a compliance schedule and a
schedule for implementation of any
required interim control measures. The
final date for compliance may not
exceed three years after the NPDWR
effective date except that the exemption
can be renewed for small systems for
limited time periods.
EPA will not list "small systems
variance technologies", as provided in
Section 1415(e)(3) of the Act, since EPA
has determined that affordable
treatment technologies exist for all
applicable system sizes and water
quality conditions. As stated in this
Section of the Act, if the Administrator
finds that small systems can afford to
comply through treatment, alternate
water source, restructuring, or
consolidation, according to the
affordability criteria established by the
Administrator, then systems are not
eligible for small systems variances.
Small systems will, however, still be
able to apply for "regular" variances
and exemptions, pursuant to Sections
1415 and 1416 of the Act.
E. Withdrawing Approval of a State
MMM Program
If EPA determines that a State MMM
program is not achieving progress
towards its MMM goals, and the State
repeatedly fails to correct, modify and
adjust implementation of its MMM
program after notice by EPA, EPA may
withdraw approval of the State's MMM
program plan. The State will be
responsible for notifying CWSs of the
Administrator's withdrawal of approval
of the State-wide MMM program plan.
The CWSs in the State would then be
required to comply with the MCL
within one year from date of
notification, or develop a State-
approved CWS MMM program plan.
EPA will work with the State to develop
a State process for review and approval
of CWS MMM program plans that meet
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the required criteria and establish a time
frame for submittal of program plans by
CWSs that choose to continue
complying with the AMCL. The review
process will allow for local public
participation in development and
review of the program plan.
X. What Do I Need To Tell My
Customers? Public Information
Requirements
A. Public Notification
Sections 1414(c)(l) and (c)(2) of the
SDWA, as amended, require that public
water systems notify persons served
when violations of drinking water
standards occur. EPA recently proposed
to revise the current public notification
regulations to incorporate new statutory
provisions enacted under the 1996
SDWA amendments (64 FR 25963, May
13, 1999). The purpose of public
notification is to alert customers in a
timely manner to potential risks from
violations of drinking water standards
and the steps they should take to avoid
or minimize such risks.
Today's regulatory action would add
violation of the radon NPDWR to the list
of violations requiring public notice
under the May 13, 1999, proposed
public notification rule. Today's action
would make three changes to the
proposed public notification rule.
• First, Appendix A to Subpart Q
would be modified to require a Tier 2
public notice for violations of the MCL
and AMCL for all community water
systems. Under the proposed rule, Tier
2 public notices would be required for
violations and situations with potential
to have serious adverse effects on
human health. Tier 2 public notices
must be distributed within 30 days after
the violation is known, and must be
repeated every three months until the
violation is resolved.
• Second, Appendix A would also be
modified to require a Tier 3 public
notice for all radon monitoring and
testing procedure violations and for
violations of the Multimedia Mitigation
(MMM) Program Plan. Tier 3 public
notices must be distributed within a
year of the violation and could, at the
water system's option, be included in
the annual Consumer Confidence Report
(CCR).
• Third, Appendix B to Subpart Q
would be modified to add standard
health effects language, which public
water systems are required to use in
their notices when violations of the
AMCL or MMM occur. EPA proposes
that the standard health effects language
for these violations, to be included in
CCR annual reports and public notices.
The language for violation of the
(A)MCL would be as follows: "People
who use drinking water containing
radon in excess of the (A)MCL for many
years may have an increased risk of
getting lung and stomach cancer." The
language for violation of the MMM
would be as follows: "Your water
system is not complying with
requirements to promote the reduction
of lung cancer risks from radon in
indoor air, which is a problem in some
homes. Radon is a naturally occurring
radioactive gas which may enter homes
from the surrounding soil and may also
be present in drinking water. Because
your system is not complying with
applicable requirements, it may be
required to install water treatment
technology to meet more stringent
standards for radon in drinking water.
The best way to reduce radon risk is to
test your home's indoor air and, if
elevated levels are found, hire a
qualified contractor to fix the problem.
For more information, call the National
Safety Council's Radon Hotline at 1-
800-SOS-RADON." The standard
health effects language public water
systems are to use in their public notice
would be identical to that used in the
annual CCR.
The final public notification rule is
expected to be published around
December, 1999, well in advance of the
August, 2000, deadline for the final
radon regulation. The final public
notification requirements for radon,
therefore, will be published with the
final radon rule. The Agency will
republish the tables in Appendices A
and B to Subpart Q of Part 141 with all
necessary changes in the final rule.
B. Consumer Confidence Report
Section 1414(d) of the SDWA requires
that all community water systems
provide annual water quality reports (or
consumer confidence reports (CCRs)) to
their customers. In their reports,
systems must provide, among other
things, the levels and sources of all
detected contaminants, the potential
health effects of any contaminant found
at levels that violate EPA or State rules,
and short educational statements on
contaminants of particular interest.
Today's action updates the standard
CCR rule requirements in subpart O 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. Systems that detect
radon at a level that violates the A/MCL
would have to include in their report a
clear and understandable explanation of
the violation including: the length of the
violation, actions taken by the system to
address the violation, and the potential
health effects (using the language
proposed today for Appendix C to
subpart O: "People who use drinking
water containing radon in excess of the
(A) MCL for many years may have an
increased risk of getting lung and
stomach cancer"). This approach is
comparable to that used for other
drinking water contaminants.
In addition, recognizing the novelty of
the MMM approach and the interest that
consumers may have in participating in
the design of the MMM program, today's
action also proposes that any system
that has ground water as a source must
include information in its report in the
years between publication of the final
rule and the date by which States, or
systems, will be required to implement
an MMM program. 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 the Radon Hotline (800-
SOS-RADON) or visit EPA's radon web
site (www.epa.gov/iaq/radon) for more
information. A system would be able to
use language provided in the proposed
rule by EPA or could chose to tailor the
wording to its specific local
circumstances in consultation with the
primacy agency. EPA recognizes that
this creates a slight additional burden
on community water system operators,
but believes that the value of strong
public support for, and participation in,
the creation of the MMM program
outweighs this burden. EPA also
recognizes that this notice may provoke
some confusion, since CCRs would alert
consumers to the risks presented by a
contaminant which most systems have
never monitored in their water,
although the notice would state that the
system would be testing and would
provide customers with the results. EPA
is requesting comment on this proposed
notice.
Finally, the Agency will republish the
tables in Appendices A, B, and C to
Subpart O of Part 141 with all necessary
changes in the final rule.
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59307
Risk Assessment and Occurrence
XI. What Is EPA's Estimate of the Levels
of Radon in Drinking Water?
A. General Patterns of Radon
Occurrence
Radon levels in ground water in the
United States are generally highest in
New England and the Appalachian
uplands of the Middle Atlantic and
Southeastern States. There are also
isolated areas in the Rocky Mountains,
California, Texas, and the upper
Midwest where radon levels in ground
water tend to be higher than the United
States average. The lowest ground water
radon levels tend to be found in the
Mississippi Valley, lower Midwest, and
Plains States. The following map shows
the general patterns of radon occurrence
in those States for which data are
available.
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59309
In addition to large-scale regional
variation, radon levels in ground water
vary significantly over a smaller area.
Local differences in geology tend to
greatly influence the patterns of radon
levels observed at specific locations.
(This means, for example, that not all
radon levels in New England are high
and not all radon levels in the Gulf
Coast region are low). Over small
distances, there is often no consistent
relationship between radon levels in
ground water and uranium or other
radionuclide levels in the ground water
or in the parent bedrock (Davis and
Watson 1989). Similarly, no significant
geographic correlation has been found
between radon levels in groundwater
systems and the levels of other
Inorganic contaminants. Radon may be
found in groundwater systems where
other contaminants (for example,
arsenic) also occur. However, finding a
high (or low) level of radon does not
indicate that a high (or low) level of
other contaminants will also be found.
Similarly, there is little evidence that
radon occurrence is correlated with the
presence of organic pollutants. In
estimating the costs of radon removal,
EPA has taken into account the fact that
other contaminants, such as iron and
manganese, may also be present in the
water. High levels of iron and
manganese may complicate the process
of radon removal and increase the costs
of mitigation.
Radon is released rapidly from surface
water. Therefore, radon levels in
supplies that obtain their water from
surface sources (lakes or reservoirs) are
very low compared to groundwater
levels.
Because of its short half life, there are
relatively few man-made sources of
radon exposure in ground water. The
most common man-made sources of
radon ground water contamination are
phosphate or uranium mining or milling
operations and wastes from thorium or
radium processing. Releases from these
sources can result in high ground water
exposures, but generally only to very
limited populations; for instance, to
persons using a domestic well in a
contaminated aquifer as a source of
potable water (USEPA 1994a).
B. Past Studies of Radon Levels in
Drinking Water
A number of studies of radon levels
in drinking water were undertaken in
the 1970s and early 1980s. Most of these
studies were limited to small geographic
areas, or addressed systems that were
not representative of community
systems throughout the U.S. The first
attempt to develop a comprehensive
understanding of radon levels in public
water supplies was the National
Inorganics and Radionuclides Survey
(NIRS), which was undertaken by the
EPA in 1983-1984. As part of NIRS,
radon samples were analyzed from
1,000 community groundwater systems
throughout the United States. The size
distribution of systems sampled was the
same as the size distribution of
groundwater systems in U.S., and the
geographic distribution was
approximately consistent with the
regional distribution of systems.
Because of the limited number of
samples, however, the number of radon
measurements in some States was quite
small. Table XI.B. 1 summarizes the
regional patterns of radon in drinking
water supplies as seen in the NIRS
database.
TABLE XI.B.1.—RADON IN COMMUNITY GROUND WATER SYSTEMS BY REGION (ALL SYSTEM SIZES)
Region
Gulf Coast
Rooky Mountains
Arithmetic mean
(pCi/L)
1,127
629
263
278
2,933
222
213
607
Geometric mean
(pCi/L)
333
333
125
151
1,214
161
132
361
Geometric
standard deviation
(pCi/L)
4.76
3.09
3.38
3.01
3.77
2.23
2.65
2.77
Source1 USEPA 1999Q
Note- These distributions are described in two ways. First, the arithmetic means (average values) are given. In addition, the geometric mean
and aeometric standard deviation are given. This approach is taken because the distributions of radon in groundwater systems are not normal
bell-shaped curves. Instead, like many environmental data sets, it was found that the ^logarithms of the radon concentrations were normally dis-
tributed ("loqnormal distribution.") The geometric mean corresponds to the center of a bell-shaped "normal" distribution when radon concentra-
tions are expressed in logarithms. The geometric standard deviation is a measure of the spread of the bell-shaped curve, expressed in loga-
rithmic form.
The NIRS has the disadvantage that
the samples were all taken from within
the water distribution systems, making
estimation of the naturally occurring
influent radon levels difficult. In
addition, the NIRS data provide no
information to allow analysis of the
variability of radon levels over time or
within individual systems. Thus, while
the NIRS data provide statistically valid
estimates of radon levels in the systems
that were sampled, they do not
adequately represent radon levels in
some individual States, especially in
large systems.
The NIRS data formed the basis for
EPA's first estimates of the levels of
radon in community groundwater
systems in the United States (Wade
Miller 1990). They formed the basis for
estimating the impacts of EPA's 1991
Proposed Rule. These estimates were
updated in 1993, using improved
statistical methods to estimate the
distributions of radon in different size
systems (Wade Miller 1993.)
C. EPA's Most Recent Studies of Radon
Levels in Ground Water
EPA's current re-evaluation of radon
occurrence in ground water (USEPA
1999g) uses data from a number of
additional sources to supplement the
NIRS information and to develop
estimates of the national distribution of
radon in community ground water
systems of different sizes. EPA gathered
data from 17 States where radon levels
were measured at the wellhead, rather
than in the distribution systems. The
Agency then evaluated the differences
between the State (wellhead) data and
the NIRS (distribution system) data.
These differences were then used to
adjust the NIRS data to make them more
representative of ground water radon
levels in the States where no direct
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measurements at the wellhead had been
made. EPA solicits any additional data
on radon levels in community water
systems, particularly in the largest size
categories.
Table XI.C.l summarizes EPA's latest
estimates of the distributions of radon
levels in ground water supplies of
different sizes. It also provides
information on the populations exposed
to radon through community water
systems (CWS). In this table, radon
levels and populations are presented for
systems serving population ranges from
25 to greater than 100,000 customers.
The CWSs are broken down into the
following system size categories:
• Very very small systems (25-500
people served), further subdivided into
25-100 and 101-500 ranges, in response
to comments received on the 1991
proposal;
• Very small systems (501-3,300
people);
• Small systems (3,301-10,000
people);
• Medium systems "(10,001-100,000
people); and
• Large systems (greater than 100,000
people).
TABLE XI.C.L—RADON DISTRIBUTIONS IN COMMUNITY GROUNDWATER SYSTEMS
Total Systems
Geometric Mean Radon Level pCi/L
Geometric Standard Deviation
Arithmetic Mean
Population Served (Millions)
Radon Level, pCi/L
100
300
500 ..
700
1000
2000
4000
System Size (Population Served)
25-100
14,651
312
3.0
578
0.87
84.7
51.4
33.6
23.4
14.7
4.7
1.1
101-500
14,896
259
3.3
528
3.75
Proportions o
78.7
45.1
29.1
20.3
12.9
4.4
1.1
501-3,300
10,286
122
3.2
240
14.1
f Systems Exce
56.9
22.1
11.4
6.8
3.6
0.8
0.1
3,301-10,000
2,538
124
2.3
175
14.3
3ding Radon Le
60.4
14.3
4.6
1.8
0.6
0.0
0.0
>1 0,000
1,536
132
2.3
187
55.0
/els (percent)
62.9
16.2
5.5
2.3
0.8
0.1
0.0
All systems
43,907
232
3.0
442
88.1
74.0
39.0
24.2
16.5
10.2
4.9
0.8
Sources: USEPA 1999g; Safe Drinking Water Information System (1998).
Systems were broken down in this
fashion because EPA's previous
analyses have shown that the
distributions of radon levels are
different in different size systems. In the
updated occurrence analysis,
insufficient data were available to
accurately assess radon levels in various
subcategories of largest systems. Thus,
data from the two largest size categories
were pooled to develop exposure
estimates.
D. Populations Exposed to Radon in
Drinking Water
Based on data from the Safe Drinking
Water Information System (SDWIS), the
Agency estimates that approximately
88.1 million people were served by
community ground water systems in the
United States in 1998. Using the data in
Table XI.C. 1, systems serving more than
500 people account for approximately
95 percent of the population served by
community ground water systems, even
though they represent only about 33
percent of the total active systems. The
largest systems (those serving greater
than 10,000 people) serve
approximately 62.5 percent of the
people served by community ground
water systems, even though they
account for only 3.5 percent of the total
number of systems.
As noted previously, the average
radon levels vary across the system size
categories. As shown in Table XI.C.l,
the average system geometric mean
radon levels range from approximately
120 pCi/L for the larger systems to 312
pCi/L for the smallest systems. The
average arithmetic mean values for the
various system size categories range
from 175 pCi/L to 578 pCi/L, and the
population-weighted arithmetic mean
radon level across all the community
ground water supplies is 213 pCi/L
(calculations not shown). The bottom
panel of Table XI.C.l shows the
proportions of the systems with average
radon levels greater than selected
values.
Table XI.D. 1 presents the total
populations in homes served by
community ground water systems at
different radon levels, broken down by
system size category. These data show
that approximately 20 percent of the
total population served by community
ground water systems are served by
systems where the average radon levels
entering the system exceed 300 pCi/L
and 64 percent of this population are
served by systems with average radon
levels above 100 pCi/L. Less than one-
tenth of one percent of the population
is served by systems obtaining their
water from sources with radon levels
above 4,000 pCi/L.
TABLE XI.D.1.—POPULATION EXPOSED ABOVE VARIOUS RADON LEVELS BY COMMUNITY GROUND WATER SYSTEM SIZE
(THOUSANDS)
Radon level
(pCi/L)
4,000
2,000
1,000
700
500
300
100
Very very small
25-100
9.4
41
128
202
290
445
733
101-500
46
183
541
848
1,210
1,880
3,290
Very Small
501-3,300
20
119
513
962
1,620
3,140
8,080
Small
3,301-1 OK
0.2
5.7
85.5
267
672
2,080
8,760
Medium
10K-100K
0.9
21.7
289
859
2,070
6,060
23,400
Large
>100K
0.4
11.0
147
436
1,050
3,070
11,900
Total
77.2
381
1,695
3,558
6,893
16,641
56,054
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59311
XII. What Are the Risks of Radon in
Drinking Water and Air?
A. Basis for Health Concern
The potential hazard of radon was
first identified in the 1940s when an
increased incidence of lung cancer in
Bohemian underground miners was
shown to be associated with inhalation
of high levels of radon-222 in the mines.
By the 1950s, the hazard was shown to
be due mainly to the short half-life
progeny of radon-222. Based on a clear
relationship between radon exposure
and risk of lung cancer in a number of
studies in miners, national and
international health organizations have
concluded that radon is a human
carcinogen. In 1988, the International
Agency for Research on Cancer (IARC
1988) convened a panel of world experts
who agreed unanimously that sufficient
evidence exists to conclude that radon
causes cancer in humans and in
experimental animals. The Biological
Effects of Ionizing Radiation (BEIR)
Committee (NAS 1988, NAS 1999a), the
International Commission on
Radiological Protection (ICRP 1987),
and the National Council on Radiation
Protection and Measurement (NCRP
1984) also have reviewed the available
data and agreed that radon exposure
causes cancer in humans. EPA has
concurred with these determinations
and classified radon in Group A,
meaning that it is considered by EPA to
be a human carcinogen based on
sufficient evidence of cancer in humans.
After smoking, radon is the second
leading cause of lung cancer deaths in
the United States (NAS 1999a).
Most of the radon that people are
exposed to in indoor and outdoor air
comes from soil. However, radon in
ground water used for drinking or other
indoor purposes can also be hazardous.
When radon in water is ingested, it is
distributed throughout the body. Some
of it will decay and emit radiation while
in the body, increasing the risk of cancer
in irradiated organs (although this
increased risk is significantly less than
the risk from inhaling radon). Radon
dissolved in tap water is released into
indoor air when it is used for
showering, washing or other domestic
uses, or when the water is stirred,
shaken, or heated before being ingested.
This adds to the airborne radon from
other sources, increasing the risk of lung
cancer (USEPA 1991, 1994a; NAS
1999b).
B. Previous EPA Risk Assessment of
Radon in Drinking Water
1. EPA's 1991 Proposed Radon Rule
Because initial information on the
cancer risks of radon came from studies
of underground miners exposed to very
high radon levels, not much
consideration was given to non-
occupational radon exposure until
recently. As new miner groups at lower
radon exposure levels were added to the
data base, it became evident that radon
exposures in indoor air, outdoor air, and
drinking water might be important
sources of risk for the U.S. population.
In 1991, as part of developing a
regulation for radionuclides and radon
in water as required by the 1986 Safe
Drinking Water Act, EPA drafted the
Radon in Drinking Water Criteria
Document (USEPA 1991) to assess the
ingestion and inhalation risk associated
with exposure to radon in drinking
water. EPA estimated that a person's
risk of fatal cancer from lifetime use of
drinking water containing one picocurie
of radon per liter (1 pCi/L) is close to
7 chances in 10 million (7 x 10--7).
Based on this and other considerations,
EPA proposed a rule for regulating
radon levels in public water systems (56
FR 33050).
2. SAB Concerns Regarding the 1991
Proposed Radon Rule
The Radiation Advisory Committee of
EPA's Science Advisory Board (SAB)
reviewed EPA's draft criteria document
and proposed rule and identified a
number of issues that had not been
adequately addressed, including: (a)
Uncertainties associated with the
models, model parameters, and final
risk estimates; (b) high exposure from
water at the point of use (e.g., shower);
(c) risks from the disposal of treatment
byproducts; and (d) occupational
exposure due to regulation and removal
of radon in drinking water. The SAB
recommended that EPA investigate
these issues before finalizing the radon
rule. The EPA considered SAB's
recommendations in developing the
current proposal.
3. 1994 Report to Congress
In 1992, Congress passed Public Law
102-389 (the Chafee-Lautenberg
Amendment to EPA's Appropriation
Bill). This law directs the Administrator
of the EPA to report to Congress on
EPA's findings regarding the risks of
human exposure to radon and their
associated uncertainties, the costs for
controlling or mitigating that exposure,
and the risks posed by treating water to
remove radon.
In response to the SAB's comments
and the Chafee-Lautenberg Amendment,
EPA drafted a report entitled
Uncertainty Analysis of Risks
Associated with Radon in Drinking
Water (USEPA 1993b) and presented it
to the SAB in February 1993. This
document evaluated the variability and
uncertainty in each of the factors
needed to calculate human cancer risk
from water-borne radon in residences
served by community groundwater
systems, and used Monte Carlo
simulation techniques to derive
quantitative confidence bounds for the
risk estimates for each of the exposure
routes to water-borne radon. In addition,
the report summarized the risk
estimates from exposure to radon in
indoor and outdoor air.
Based on the data available at the
time, EPA estimated that the total
number of fatal cancers that will occur
as a result of exposure to water-borne
radon in homes supplied by community
groundwater systems was 192 per year.
EPA noted that the risk from water-
borne radon is small compared to the
risk of soil-derived radon in indoor air
(13,600 lung cancer cases per year) or in
outdoor air (520 lung cancer deaths per
year) (USEPA 1992b, 1993b).
The EPA included the findings of this
uncertainty analysis with the SAB
review comments in the Report to the
United States Congress on Radon in
Drinking Water: Multimedia Risk and
Cost Assessment of Radon (USEPA
1994a). This report also included an
assessment of the risk from exposure to
radon at drinking water treatment
facilities. The SAB reviewed the report
prepared by EPA, and commended the
EPA's methodologies employed in the
uncertainty analysis and the exposure
assessment of radon at the point of use
(e.g. showering). However, the SAB
stated that the estimates of risk from
ingested radon may have additional
uncertainties in dose estimation and in
the use of primarily the atomic bomb
survivor exposure (gamma emission
with low linear energy transfer) in
deriving the organ-specific risk per unit
dose for from radon and progeny (alpha
particle emission with high linear
energy transfer). The SAB also
questioned EPA's estimates of the
number of community water supplies
affected, and the extrapolation of the
risk of lung cancer associated with the
high radon exposures of uranium
miners to the low levels of exposure
experienced in domestic environments.
The SAB recommended that the Agency
use a relative risk orientation as an
important consideration in making risk
reduction decisions on all sources of
risks attributable to radon. Based on the
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comments and recommendations of the
SAB, EPA revised several of the
distributions used in the Monte Carlo
analysis and finalized the Uncertainty
Analysis of Risks Associated with
Exposure to Radon in Drinking Water
(USEPA 1995).
C. NAS Risk Assessment of Radon in
Drinking Water
1. NAS Health Risk and Risk-Reduction
Benefit Assessment Required by the
1996 Amendments to the Safe Drinking
Water Act
The 1996 amendments to the Safe
Drinking Water Act required EPA to
arrange with the National Academy of
Sciences (NAS) to conduct a risk
assessment of radon in drinking water
and an assessment of the health-risk
reduction benefits associated with
various measures to reduce radon
concentrations in indoor air. The law
also directed EPA to promulgate an
alternative maximum contaminant level
(AMCL) if the proposed MCL is less
than the concentration of radon in water
"necessary to reduce the contribution of
radon in indoor air from drinking water
to a concentration that is equivalent to
the national average concentration of
radon in outdoor air."
2. Charge to the NAS Committee
In accordance with the requirements
of the 1996 amendments to the SDWA,
in February 1997, EPA funded the NAS
National Research Council to establish a
multidisciplinary committee of the
Board of Radiation Effects Research.
This Committee on Risk Assessment of
Exposure to Radon in Drinking Water
(the NAS Radon in Drinking Water
committee) was charged to use the best
available data and methods to provide
the following:
(a) The best estimate of the central
tendency of the transfer factor for radon
from water to air, along with an
appropriate uncertainty range,
(b) Estimates of unit cancer risk (i.e.,
the risk from lifetime exposure to water
containing 1 pCi/L) for the inhalation
and ingestion exposure routes, both for
the general population and for
subpopulations within the general
population (e.g., infants, children,
pregnant women, the elderly,
individuals with a history of serious
illness) that are identified as likely to be
at greater risk due to exposure to radon
in drinking water than the general
population,
(c) Unit cancer risks from inhalation
exposure for people in different
smoking categories,
(d) Descriptions of any teratogenic
and reproductive effects in men and
women due to exposure to radon in
drinking water,
(e) Central estimates for a population-
weighted average national ambient
(outdoor) air concentration for radon,
with an associated uncertainty range.
The NAS Radon in Drinking Water
committee was also asked to estimate
health risks that might occur as the
result of compliance with a primary
drinking water regulation for radon. The
committee was to assess the health risk
reduction benefits associated with
various mitigation measures to reduce
radon levels in indoor air.
3. Summary of NAS Findings
The NAS completed its charge and
issued a report entitled "Risk
Assessment of Radon in Drinking
Water" (NAS 1999b). The NAS report
provides detailed descriptions of the
methods and assumptions employed by
the NAS Radon in Drinking Water
committee in completing its evaluation.
The following text provides a summary
of the NAS report.
(a) National Average Ambient Radon
Concentration. Because radon levels in
outdoor air vary from location to
location, the NAS Radon in Drinking
Water committee concluded that
available data are not sufficiently
representative to calculate a population-
weighted annual average ambient radon
concentration. Based on the data that
are available, the NAS Radon in
Drinking Water committee concluded
that the best estimate of an unweighted
arithmetic mean radon concentration in
ambient (outdoor) air in the United
States is 15 Bq/m3 (equal to 0.41 pCi/L
of air), with a confidence range of 14 to
16 Bq/ms (0.38-0.43 pCi/L air).
(b) Transfer Factor. The relationship
between the concentration of radon in
water and the average indoor air
concentration of water-derived radon is
described in terms of the transfer factor
(pCi/L in air per pCi/L in water). Most
researchers who have investigated this
variable in residences find that it can be
described as a lognormal distribution of
values, most conveniently characterized
by the arithmetic mean (AM) and the
standard deviation (Stdev), or by the
geometric mean (GM) and the geometric
standard deviation (GSD). The NAS
Radon in Drinking Water committee
performed an extensive review of both
measured and calculated values of the
transfer factor in residences, with the
results summarized in the following
Table XII. 1:
TABLE XII.1.—MEASURED AND MODELED TRANSFER FACTORS
Measured
Modeled
Approach
AM
0 87 x 10"*
1.2x10-"
Stdev
1 2 x 10~"
2.4x10-"
GM
o QQ y -JA— 4
0.55x10-"
GSD
30
3.5
» Calculated from, GM and GSD.
The committee concluded that there
is reasonable agreement between the
average value of the transfer factor
estimated by the two approaches, and
identified 1 in 10,000 (1.0 x 10-4) as the
best central estimate of the transfer
factor for residences, with a confidence
bound of about 0.8 to 1.2 x 10-4. This
central tendency value is the same as
has been used in previous assessments
'(USEPA 1993b, 1995).
Based on this transfer factor, the NAS
committee concluded that the AMCL for
radon in drinking water would be
150,000 Bq/m3 (about 4,000 pCi/L).
That is, a concentration of 4,000 pCi/L
of radon in water is expected to increase
the concentration of radon in indoor air
by an amount equal to that in outdoor
air.
(c) Biologic Basis of Risk Estimation.
Both the BEIR VI Report (NAS 1999a)
and their report on radon in drinking
water (NAS 1998b) represent the most
definitive accumulation of scientific
data gathered on radon since the 1988
NAS BEIR IV (NAS 1988). These
committees' support for the use of linear
non-threshold relationship for radon
exposure and lung cancer risk came
primarily from their review of the
mechanistic information on alpha-
particle-induced carcinogenesis,
including studies of the effect of single
versus multiple hits to cell nuclei.
The NAS BEIR VI Committee (NAS
1999a) conducted an extensive review
of information on the cellular and
molecular mechanism of radon-induced
cancer in order to help support the
assessment of cancer risks from low
levels of radon exposure. In the BEIR VI
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59313
report (NAS 1999a), the HAS 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. Alpha
particles, such as those that are emitted
from the radon decay chain, produce
dense trails of ionized molecules when
they pass through a cell, causing
cellular damage. Alpha particles passing
through the nucleus of a cell can
damage DNA. In their report, the BEIR
VI Committee 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. The Committee
also noted that epldemiological data
relating to low radon exposures in
mines also indicate that a single alpha
track through the cell may lead to
cancer. Finally, while not definitive by
themselves, the results from residential
case-control studies provide some direct
support for the conclusion that
environmental levels of radon pose a
risk of lung cancer. 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 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. 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.
(d) Unit Risk from Inhalation
Exposure to Radon Progeny. The
calculation of the unit risk from
inhalation of radon progeny derived
from water-borne radon depends on four
key variables: (1) The transfer factor that
relates the concentration of radon in air
to the concentration in water, (2) the
equilibrium factor (the level of radon
progeny present compared to the
theoretical maximum amount), (3) the
occupancy factor (the fraction of full
time that a person spends at home) and
(4) the risk of lung cancer per unit
exposure (the risk coefficient). The
values utilized by NAS for each of these
factors are summarized next.
Transfer Factor
The NAS Radon in Drinking Water
committee (NAS 1999b) reviewed
available data and concluded that the
best estimate of the transfer factor is 1.0
x 10~4 pCi/L air per pCi/L water.
Equilibrium Factor
At radiological equilibrium, 1 pCi/L
of radon in air corresponds to a
concentration of 0.010 Working Levels
(WL) of radon progeny. One WL is
defined as any combination of
radioactive chemicals that result in an
emission of 1.3 x 10s MeV of alpha
particle energy. One WL is
approximately the total amount of
energy released by the short-lived
progeny in equilibrium with 100 pCi of
radon. Under typical household
conditions, processes such as
ventilation and plating out of progeny
prevent achievement of equilibrium,
and the level of radon progeny present
is normally less than 0.010 WL. The
equilibrium factor (EF) is the ratio of the
alpha energy actually present in
respirable air compared to the
theoretical maximum at equilibrium.
Based on a review of measured values
in residences, USEPA (1993b, 1995)
identified a value of 0.4 as the best
estimate of the mean, with a credible
range of 0.35 to 0.45. NAS (1999a,
1999b) reviewed the data and also
selected a value of 0.4 as the most
appropriate point estimate of EF.
Occupancy Factor
The occupancy factor (the fraction of
time that a person spends at home)
varies with age and occupational status.
Studies on the occupancy factor have
been reviewed by EPA (USEPA 1992b,
1993b, 1995), who found that a value of
0.75 is the appropriate point estimate of
the mean with a credible range of 0.65-
0.80. Based on a review of available
data, both the BEIR VI committee (NAS
1999a) and the NAS Radon in Drinking
Water committee (NAS 1999b)
identified an occupancy factor of 0.7 as
the best estimate to employ in
calculation of the inhalation unit risk
from inhalation of radon progeny.
Risk of Lung Cancer Death per Unit
Exposure (Risk Coefficient)
There are extensive data on humans
(mainly from studies of underground
miners) establishing that inhalation
exposure to radon progeny causes
increased risk of lung cancer (NAS
1999a, 1999b). The basic approach used
by NAS to quantify the risk of fatal
cancer (specifically death from lung
cancer) from inhalation of radon
progeny in air was to employ empirical
dose-response relationships derived
from studies of humans exposed to
radon progeny in the environment. The
most recent quantitative estimate of the
risk of lung cancer associated with
inhalation of radon progeny has been
conducted by the BEIR VI committee
(NAS 1999a), and this analysis was
employed by the NAS Radon in
Drinking Water committee (NAS 1999b).
The BEIR VI committee reviewed all of
the most current data from studies of
humans exposed to radon, including
cohorts of underground miners and
residents exposed to radon in their
home, as well as studies in animals and
in isolated cells. Because of differences
in exposure level and duration, studies
of residential radon exposure would
normally be preferable to studies of
miners for quantifying risk to residents
from radon progeny in indoor air.
However, the BEIR VI committee found
that the currently available
epidemiological studies of residents
exposed in their homes are not
sufficient to develop reliable
quantitative exposure-risk estimates
because (a) the number of subjects is
small, (b) the difference between
exposure levels is limited, and (c)
cumulative radon exposure estimates
are generally incomplete or uncertain.
Therefore, the BEIR VI committee
focused their analysis on studies of
radon-exposed underground miners.
The method used by the BEIR VI
committee was essentially the same as
used previously by the BEIR IV
committee (NAS 1988), except that the
database on radon risk in underground
miners is now much more extensive,
including 11 cohorts of underground
miners, which, in all, include about
2,700 lung cancers among 68,000
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miners, representing nearly 1.2 million
person-years of observations. Details of
these 11 cohorts are presented in the
NAS BEIR VI Report (NAS 1999a). For
.historical reasons, the measure of
exposure used in these studies is the
Working Level Month (WLM), which is
defined as 170 hours of exposure to one
Working Level (WL) of radon progeny.
Based on evidence that risk per unit
exposure increased with decreasing
exposure rate or with increasing
exposure duration (holding cumulative
exposure constant), the BEIR VI
committee modified the previous risk
model to include a term to account for
this "inverse dose rate" effect. Because
the adjustment could be based on either
the concentration of radon progeny or
the duration of exposure, there are two
alternative forms of the preferred
model—the "exposure-age-
concentration" model, and the
"exposure-age-duration" model. For
brevity, these will generally be referred
to here as the "concentration" and
"duration" models. ' • •
Mathematically, both models can be
represented as:
RR= 1 +ERR= 1 +p (cos-14+91 s-24»i 5-24+625+
0025 + )ageYz (1)
Where:
RR=relative risk of lung cancer in a
person due to above-average radon
exposure compared to the average
background risk for a similar person
in the general population
ERR=Excess relative risk (the increment
in risk due to the above-average
exposure to radon)
P=exposure-response parameter (excess
relative risk per WLM)
a>5-i4=exposures (WLM) incurred from
5-14 years prior to the current age
oois-24=exposures (WLM) incurred from
15-24 years prior to the current age
Cfl25+=exposures (WLM) incurred 25 or
more years prior to the current age
6i5-24=time-since-exposure factor for risk
from exposures incurred 15-24
years or more before the attained
age
92s+=time-since-exposure factor for risk
from exposures incurred 25 or more
years or more before the attained
age
<)>age=effect-modification factor for
attained age
•yz=effect-modification factor for
exposure rate or exposure duration
The BEIR VI committee used a two-
stage approach for combining
information from the 11 miner studies
to derive parameters for the
concentration and duration risk models.
First, estimates of model parameters
were derived for each study cohort, and
then population-weighted averages of
the parameters were calculated across
studies to derive an overall estimate that
takes variation between and within
cohorts into account. The results of the
pooled analysis of all of the miner data
indicated that, for a given level of
exposure to radon, the excess relative
risk of lung cancer decreases with
increasing time since exposure,
decreases as a function of increased
attained age, increases with increasing
duration of exposure, and decreases
with increasing exposure rate (the
inverse dose rate effect).
The BEIR VI committee applied the
risk models to 1985-89 U.S. mortality
data to estimate individual and
population risks from radon in air. At
the individual level, the committee
estimated the lifetime excess relative
risk (ERR), which is the percent increase
in the lifetime probability of lung cancer
death from indoor radon exposure. For
population risks, the committee
estimated attributable risk (AR), which
indicates the proportion of lung-cancer
deaths that theoretically may be reduced
by reduction of indoor radon
concentrations to outdoor levels.
Extrapolation From Mines to Homes
Because of a number of potential
differences between mines and homes,
exposures to equal levels of radon
progeny may not always result in equal
doses to lung cells. The ratio of the dose
to lung cells in the home compared to
that in mines is described by the K
factor. Based on the best data available
at the time, NAS (1991) had previously
concluded that the dose to target cells
in the lung was typically about 30
percent lower for a residential exposure
compared to an equal WLM exposure in
mines (i.e., K = 0.7). The BEIR VI
committee re-examined the issue of the
relative dosimetry in homes and mines.
In light of new information regarding
exposure conditions in home and mine
environments, the committee concluded
that, when all factors are taken into
account, the dose per WLM is nearly the
same in the two environments (i.e., a
best estimate for the K-factor is about 1)
(NAS 1999a). The major factor
contributing to the change was a
downward revision in breathing rates
for miners. Thus, for calculation of risks
from residential exposures, Equation 1
can be applied directly without
adjustment.
Combined Effect of Smoking and Radon
Because of the strong influence of
smoking on the risk from radon, the
BEIR VI committee (NAS 1999a)
evaluated risk to ever-smokers and
never-smokers separately. The
committee had information on 5 of the
miner cohorts, from which they
concluded that the combined effects of
radon and smoking were more than
additive but less than multiplicative. As
a best estimate the committee
determined that never-smokers should
be assigned a relative risk coefficient (p)
about twice that for ever-smokers, in
each of the two models defined
previously. This means that the
attributable risk, or the proportion of all
lung cancers attributable to radon, is
about twice as high for never-smokers as
ever-smokers. Nevertheless, because the
incidence of lung cancer is much greater
for ever-smokers than never-smokers,
the probability of a radon induced lung
cancer is still much higher for ever-
smokers. This higher risk in ever-
smokers arises from the synergism
between radon and cigarette smoke in
causing lung cancer.
Based on the BEIR VI lifetime relative
risk results, the NAS Radon in Drinking
Water committee (NAS 1999b)
calculated the lifetime risk (per Bq/m3
air) for each of the two models using the
following basic equation:
Excess lifetime risk= (Baseline risk)*
(LRR-1)
Where LRR=lifetime relative risk
Baseline lung cancer risk values used
by the NAS Radon in Drinking Water
committee (NAS 1999b) are summarized
in Table XII.2.
TABLE XII.2.—BASELINE LUNG CANCER RISK
Gender
Male
Female
Smoking
prevalence
A CO
0.42
Ever-smok-
ers1
0.068
Never-
smokers
0.0059
1 Ever-smokers were defined as persons who had smoked at least 100 cigarettes in their entire life (CDC 1995).
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59315
The NAS Radon in Drinking Water
committee (NAS 1999b) adopted the
average of the results from each of the
two models as the best estimate of
lifetime risk from radon progeny.
Results: Inhalation Unit Risk for Water- NAS calculated the inhalation unit risk
Borne Radon Progeny
Based on the inputs and approaches
summarized in the previous sections,
TABLE XII.3.—LIFETIME UNIT RISK
for radon progeny, by smoking category,
with the results described in Table
XII.3:
Smoking category
Evor Smokers . ...
Never Smokers
per Bq/m 3 in
air
1.6x10-"
2.6x10-"
0.5x10-"
per pCi/L in
water
5.93x10-'
9.63x10-'
1.85x10-'
Lifetime
(yrs)
74.9
73.7
76.1
Annual unit
risk
(per pCi/L in
water)
7.92x10-«
1.31x10-8
2.43x10-9
Inhalation
risk coeffi-
cient
(per WLM)
5.49x10-"
9.07x10-"
1.68x10-"
The NAS Radon in Drinking Water
committee (NAS 1999b) estimated that
the uncertainty around the inhalation
risk coefficient for radon progeny can be
characterized by a lognormal
distribution with a GSD of 1.2 (based on
the duration model) to 1.3 (based on the
concentration model). This corresponds
to an uncertainty range for the
combined population of about 3.4 x 10-
4 to 8.1 x 10-4 lung cancer deaths per
person per WLM.
Inhalation Risks to Subpopulations,
Including Children
The NAS Radon in Drinking Water
committee concluded that, except for
the lung-cancer risk to smokers, there is
insufficient information to permit
quantitative evaluation of radon risks to
susceptible sub-populations such as
Infants, children, pregnant women,
elderly and seriously ill persons.
The BEIR VI committee (NAS 1999a)
noted that there is only one study (tin
miners in China) that provides data on
whether risks from radon progeny are
different for children, adolescents, and
adults. Based on this study, the
committee concluded that there was no
clear indication of an effect of age at
exposure, and the committee made no
adjustments in the lung cancer risk
model for exposures received at early
ages.
(e) Unit Risk for Ingestion Exposure.
The calculation of the unit risk from
ingestion of radon in water depends on
three key variables: (1) The amount of
radon-containing water ingested, (2) the
fraction of radon lost from the water
before ingestion, and (3) the risk to the
tissues per unit of radon absorbed into
the body (risk coefficient). The values
utilized by NAS for each of these factors
are summarized next.
Water Ingestion Rate
EPA (USEPA 1993b, 1995) performed
a review of available data on the amount
of water ingested by residents. In brief,
water ingestion can be divided into two
categories: direct tap water (that which
is ingested as soon as it is taken from
the tap) and indirect tap water (water
used in cooking, for making coffee, etc.).
Available data indicate nearly all radon
is lost from indirect tap water before
ingestion, so only direct tap water is of
concern. Based on available data
(Pennington 1983; USEPA 1984; Ershow
and Cantor 1989, USEPA 1993b, USEPA
1995) scientists estimated that the mean
of the direct tap water ingestion rate was
0.65 liters per day (L/day), with a
credible range of about 0.57 to 0.74 L/
day. Based mainly on this analysis, NAS
(1999b) identified 0.6 L/day as the best
estimate of direct tap water intake, and
utilized this value in the calculation of
the unit risk from radon ingestion. This
value includes direct tap water ingested
at all locations, and so includes both
residential and non-residential
exposures.
The analysis conducted for radon in
drinking water uses radon-specific
estimates of water consumption, based
on guidance from the NAS Radon in
Drinking Water committee. Based on
radon's unique characteristics, this
approach is different from the Agency's
approach to other drinking water
contaminants.
In general, in calculating the risk for
all other water contaminants, EPA uses
2 liters per day as the average amount
of water consumed by an individual.
For radon, the Agency used 0.6 liters
per day to estimate the risks of radon
ingestion. The NAS ingestion risk
number is derived from an average risk/
radiation coefficient, an average
drinking water ingestion rate, and an
average life expectancy. NAS chose to
use an ingestion rate of 0.6 liter per day,
based on an assumption that only 0.6
liters of the "direct" water will retain
radon. Since radon is very readily
released during normal household water
use, we assume that radon in water used
for indirect purposes (cooking, making
coffee, etc) is released before drinking.
Only direct water (drinking from tap
directly) is used to estimate ingestion
risk.
The Agency solicits^comments on this
approach to estimating the ingestion
risk of radon in drinking water,
particularly the assumption of 0.6 liters
per day direct consumption.
Fraction of Radon Remaining During
Water Transfer From the Tap
Because radon is a gas, it tends to
volatilize from water as soon as the
water is discharged from the plumbing
system into any open container or
utensil. As would be expected, the
fraction of radon volatilized before
consumption depends on time,
temperature, surface area-to-volume
ratio, and degree of mixing or aeration.
A previous analysis by EPA (USEPA
1995) identified a value of 0.8 as a
reasonable estimate of the mean fraction
remaining before ingestion, with an
estimated credibility interval about the
mean of 0.7 to 0.9. Because data are so
sparse, and in order to be conservative,
NAS assumed a point estimate of 1.0 for
this factor (NAS 1999b).
Risk per Unit of Radon Absorbed (Risk
Coefficient)
The NAS Radon in Drinking Water
committee reviewed a number of
publications on the risk from ingestion
of radon, and noted that there was a
wide range in the estimates, due mainly
to differences and uncertainties in the
way radon is assumed to be absorbed
across the gastrointestinal tract.
Therefore, the committee developed
new mathematical models of the
diffusion of radon in the stomach and
the behavior of radon dissolved in blood
and other tissues to calculate the
radiation dose absorbed by tissues
following ingestion of radon dissolved
in water (NAS 1999b).
NAS determined that the stomach
wall has the largest exposure (and hence
the largest risk of cancer) following oral
exposure to radon in water, but that
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there is substantial uncertainty on the
rate and extent of radon entry into the
wall of the stomach from the stomach
contents. The "base case" used by NAS
assumed that diffusion of radon from
the stomach contents occurs through a
surface mucus layer and a layer of non-
radiosensitive epithelial cells before
coming into proximity with the
radiosensitive stem cells. Below this
layer, diffusion into capillaries was
assumed to remove radon and reduce
the concentration to zero. Based on this
model, the concentration of radon near
the stem cells was about 30 percent of
that in the stomach contents.
The distribution of absorbed radon to
peripheral tissues was estimated by
NAS using a physiologically-based
pharmacokinetic (PBPK) model based
on the blood flow model of Leggett and
Williams (1995). The committee's
analysis considered that each
radioactive decay product formed from
radon decay in the body exhibited its
own behavior with respect to tissues of
deposition, retention, and routes of
excretion with the ICRP's age-specific
biokinetic models The computational
method used by the NAS Radon in
Drinking Water committee to calculate
the age-and gender-averaged cancer
death risk from lifetime ingestion of
radon is described in EPA's Federal
Guidance Report 13 (USEPA 1998d).
Results: Ingestion Unit Risk
The NAS Radon in Drinking Water
committee estimated that an age- and
gender-averaged cancer death risk from
lifetime ingestion of radon dissolved in
drinking water at a concentration of 1
Bq/L probably lies between 3.8 x 10~7
and 4.4 x lO"6, with 1.9 x IQ-6 as the
best central value. This is equivalent to
a lifetime risk of 7.0 x 10 ~8 per pCi/L,
with a credible range ofl.4xlO~8to
1.6 x 10 -? per pCi/L. This uncertainty
range is based mainly on uncertainty in
the estimated dose to the stomach and
in the epidemiologic data used to
estimate the risk (NAS 1999b), and does
not include the uncertainty in exposure
factors such as average daily direct tap
water ingestion rates or radon loss
before ingestion. The lifetime risk
estimate of 7.0 x lO"8 per pCi/L
corresponds to an ingestion risk
coefficient of 4.29 x 10~i2 per pCi
ingested.
Ingestion Risk to Children
NAS (1999b) performed an analysis to
investigate the relative contribution of
radon ingestion at different ages to the
total risk. This analysis considered the
age dependence of: radon consumption,
behavior of radon and its decay
products in the body, organ size, and
risk. The results indicated that even
though water intake rates are lower in
children than in adults, dose
coefficients are higher in children
because of their smaller body size. In
addition, the cancer risk coefficient for
ingested radon is greater for children
than for adults. Based on dose and
stomach cancer risk models, NAS
(1999b) estimated that about 30% of
lifetime ingestion risk was due to
exposures occurring during the first 10
years of life. However, the NAS found
no direct epidemiological evidence to
suggest that any sub-population is at
increased risk from ingestion of radon.
In addition, ingestion risk as a whole
accounts for only 11% of total risk from
radon exposure from drinking water for
the general population, with inhalation
accounting for the remaining 89%. The
NAS did not identify children, or any
other groups except smokers, as being at
significantly higher overall risk from
exposure to radon in drinking water.
(f) Summary of NAS Lifetime Unit
Risk Estimates. Table XII.4 summarizes
the lifetime average unit risk estimates
derived by the NAS Radon in Drinking
Water committee.
TABLE XII.4.—NAS RADON IN DRINKING WATER COMMITTEE ESTIMATE OF LIFETIME UNIT RISK POSED BY EXPOSURE TO
RADON IN DRINKING WATER
Exposure route
Inhalation
Ingestion
Total Risk (inhalation + ingestion)
Smoking status
Ever
Never
All
All
All
Gender-averaged lifetime
unit risk
Risk per Bq/
L in water
2.6x10-5
0.50x10-5
1 6 x 10~5
0.19x10-5
1.8 x 10-5
Risk per pCi/
L in water
9.6x10-7
1.9x10-7
5.9x10-7
7.0x10-8
6.6x10-7
(g) Other Health Effects. The NAS
Radon in Drinking Water committee was
asked to review teratogenic and
reproductive risks from radon. The
committee concluded there is no
scientific evidence of teratogenic and
reproductive risks associated with either
inhalation or ingestion of radon.
(h) Relative Magnitude of the Risk
from Radon in Water. The NAS Radon
in Drinking Water committee concluded
that radon in water typically adds only
a small increment to the indoor air
concentration. The committee estimated
the cancer deaths per year due to radon
in indoor air (total), radon in outdoor
air, radon progeny from waterborne
radon, and ingestion of radon in water
are 18, 200, 720, 160, and 23,
respectively. However, the committee
recognized that radon in water is the
largest source of cancer risk in drinking
water compared to other regulated
chemicals in water.
D. Estimated Individual and Population
Risks
Based on the findings and
recommendations of the NAS Radon in
Drinking Water committee, EPA has
performed a re-evaluation of the risks
posed by radon in water (USEPA
1999b). This assessment relied upon the
inhalation and ingestion unit risks
derived by NAS (1999b), and calculated
risks to individuals and the population
by combining the unit risks derived by
NAS with the latest available data on
the occurrence of radon in public water
systems (USEPA 1999g).
In brief, the risk to a person from
exposure to radon in water is calculated
by multiplying the concentration of
radon in the water (pCi/L) by the unit
risk factor (risk per pCi/L) for the
exposure pathway of concern (ingestion,
inhalation). The population risk (the
total number of fatal cancer cases per
year in the United States due to radon
ingestion in water) is estimated by
multiplying the average annual
individual risk (cases per person per
year) by the 'total number of people
exposed. Data which EPA used to
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59317
calculate individual risks and
population risks are summarized next.
Radon Concentration in Community
Water Systems
The EPA has recently completed a
detailed review and evaluation of the
latest available data on the occurrence
of radon in community water systems
(USEPA 1999g; see Section XI). In brief.
the concentration of radon in drinking
water from surface water sources is very
low, and exposures from surface water
systems can generally be ignored.
However, radon does occur in most
groundwater systems, with the
concentration values tending to be
highest in areas where groundwater is in
contact with granite. In addition, radon
concentrations tend to vary as a
function of the size of the water system,
being somewhat higher in small systems
than in large systems (USEPA 1999g).
Based on EPA's analysis, the
population-weighted average
concentration of radon in community
ground water systems is estimated to be
213 pCi/L, with a credible range of
about 190 to 240 pCi/L (USEPA 1999g).
Total Exposed Population
Based on data available from the Safe
Drinking Water Information System
(SDWIS), EPA estimates that 88.1
million people (about one-third of the
population of the United States) are
served in their residence by community
water supply systems using ground
water (USEPA 1998a).
Based on these data on radon
occurrence and size of the exposed
population, EPA calculated the risks
from water-borne radon to people
exposed at residences served by
community groundwater systems. EPA
also calculated revised quantitative
uncertainty analysis of the risk
estimates at residential locations,
incorporating NAS estimates of the
uncertainty inherent in the unit risks for
each pathway. In addition, EPA
performed screening level estimates of
risk to people exposed to water-borne
radon in various types of non-
residential setting. EPA's findings are
summarized next.
1. Risk Estimates for Ingestion of Radon
in Drinking Water
Table XII.5 presents EPA's estimate of
the mean individual risk (fatal cancer
cases per person per year) for the people
who ingest water from community
ground water systems. This includes
exposures that occur both in the
residence and in non-residential settings
(the workplace, restaurants, etc). The
lower and upper bounds around the best
estimate were estimated using Monte
Carlo simulation techniques (USEPA
1999b).
TABLE XII.5.—ESTIMATED RISK FROM RADON INGESTION AT RESIDENTIAL AND NON-RESIDENTIAL LOCATIONS SERVED BY
COMMUNITY WATER SYSTEMS
Parameter
Lower bound
3.2x10-8
3
Best
estimate
2.0x10-'
18
Upper bound
4.3 x 10-7
38
2. Risk Estimates for Inhalation of Radon Progeny Derived From Waterborne Radon
(a) Inhalation Exposure to Radon Progeny in the Residential Environment. Table XII.6 presents the EPA's best estimate
of the mean individual risk and population risk of lung cancer fatality due to inhalation of radon progeny derived
from water-borne radon at residences served by community groundwater systems. Lower and upper bounds on the
Individual and population risk estimates were derived using Monte Carlo simulation techniques.
TABLE XII.6.—ESTIMATED RISKS FROM INHALATION OF WATER-BORNE RADON PROGENY IN RESIDENCES SERVED BY
COMMUNITY GROUND WATER SUPPLY SYSTEMS
Parameter
Population Risk (lung cancer deaths per year)
Lower bound
7.9 x10~7
70
Best
estimate
1.7x10-6
148
Upper bound
3.0x10-6
263
Of the total number of lung cancer
deaths due to water-borne radon, most
(about 84 percent) are expected to occur
in ever-smokers, with the remainder
(about 16 percent) occurring in never-
smokers.
Analysis of Peak Exposures and Risks
Due to Showering
Both NAS and EPA have paid special
attention to the potential hazards
associated with high exposures to radon
that may occur during showering. High
exposure occurs during showering
because a large volume of water is used,
release of radon from shower water is
nearly complete, and the radon enters a
fairly small room (the shower/
bathroom). However, both NAS (1999b)
and USEPA (1993b, 1995) concluded
that the risk to humans from radon
released during showering was likely to
be small. This is because the inhalation
risk from radon is due almost entirely to
radon progeny and not to radon gas
itself, and it takes time (several hours)
for the radon progeny to build up from
the decay of the radon gas released from
the water. For example, in a typical
shower scenario (about 10 minutes), the
level of progeny builds up to only 2 to
4 percent of its maximum possible
value. Thus, showering is one of many
indoor water uses that contribute to the
occurrence of radon in indoor air, but
hazards from inhalation of radon during
showering are not of special concern.
(b) Inhalation Exposure to Radon
Progeny in the Non-Residential
Environment. The results summarized
to this point relate to exposures which
occur in homes. However, on average,
people spend about 30 percent of their
time at other locations. Surveys of
human activity patterns reveal that time
outdoors or in cars accounts for about
13 percent of the time (USEPA 1996),
and about 17 percent of the time, on
average across the entire population
(including both workers and non-
workers), is spent in non-residential
structures. Such non-residential
buildings are presumably all served
with water, so exposure to radon and
radon progeny is expected to occur, at
least in buildings served by
groundwater. Because data needed to
quantify exposure at non-residential
locations are limited, EPA has
performed only a screening
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level evaluation to date. This evaluation
may be revised in the future, depending
on the availability of more detailed and
appropriate input data.
As with exposures in the home, the
largest source of exposure and risk from
water-borne radon in non-residential
buildings is inhalation of radon
progeny. Limited data were found on
measured transfer factors in non-
residential buildings, so values were
estimated for several different types of
buildings based on available data on
water use rates, building size, and
ventilation rate, based on the following
basic equation:
TF = (W«e)/(V.A.)
Where:
W = Water use (L/person/day)
e = Use-weighted fractional release of
radon from water to air
V = Building volume (L/person)
A, = Ventilation rate (air changes/day)
The resulting transfer factor values
varied as a function of building type,
based on limited data, but the average
across all building types was about 1 x
10~4 (the same as for residences). Very
few data were located for the
equilibrium factor in non-residential
buildings, so a value of 0.4 (the same as
in a residence) was assumed (USEPA
1999b).
Based on an estimated average
transfer factor of 1 x 10 ~4 and assuming
an average occupancy factor of 17
percent at non-residential locations, the
estimated lifetime and annual risks of
death from lung cancer due to exposure
per unit concentration of radon (IpCi/L)
in water are 1.4 x 10~7 per pCi/L and
1.9 x 10~9 per pCi/L, respectively.
Assuming a mean radon
concentration in water of 213 pCi/L,
these unit risks correspond to lifetime
and annual individual risks of 3.1 x
10~5 and 4.1 x 10"7 lung cancer deaths
per person. Assuming the same
population size of 88.1 million
population exposed to radon through
community ground water supplies,
EPA's best estimate of the number of
fatal cancer cases per year resulting
from the inhalation of radon progeny in
non-residential environments is 36 lung
cancer deaths per year (USEPA 1999b)
(from the population of individuals
exposed in non-residential settings
served by community ground water
supplies).
(c) Analysis of Risk Associated with
Exposure at NTNC Locations. A subset
of the water systems serving non-
residential populations are the non-
transient non-community (NTNC)
systems. Statistics from SDWIS indicate
there are about 5.2 million individuals
exposed at buildings served by NTNC
groundwater systems (USEPA 1999b).
Data on radon exposures at locations
served by NTNC systems are limited.
However, data are available for water
used and population size at each of 40
strata of NTNC systems (USEPA 1998a).
Assuming (a) the exposure at NTNC
locations is occupational in nature with
about 8 hr/day, 250 days/yr, and 25
years per lifetime for workers and 8 hr/
day, 180 days/yr, and 12 years per
lifetime for students, (b) the same
transfer factor (1 x 10~4) and
equilibrium factor (0.4) assumed for
other non-residential buildings apply at
NTNC locations, and (c) the
concentration of radon in water at
NTNC locations is about 60 percent
higher than in community water
systems (mean concentration = 341 pCi/
L) (see Section XI of this preamble),
then the estimated population-weighted
average individual annual and lifetime
lung cancer risks are 2.6 x 10~7 and 2.0
x 10~5, respectively.
3. Risk Estimates for Inhaling Radon Gas
NAS (1999b) did not derive a unit risk
factor for inhalation of radon gas, but
provided in their report a set of annual
effective doses to tissues (liver, kidney,
spleen, red bone marrow, bone surfaces,
other tissues) from continuous exposure
to IBq/m3 of radon in air. These doses
to internal organs from the decay of
radon gas absorbed across the lung and
transported to internal sites were based
on calculations by Jacob! and Eisfeld
(1980). Based on these dose estimates,
EPA estimated a unit risk value using an
approach similar to that used by NAS to
derive the unit risk for ingestion of
radon gas in water. The organ-specific
doses reported by Jacobi and Eisfeld
were multiplied by the lifetime-average
organ-specific and gender-specific risk
coefficients (risk of fatal cancer per rad)
from Federal Guidance Report No, 13
(USEPA 1998d). Based on an average
transfer factor of 1 x 10~4, and assuming
70 percent occupancy, the estimated
annual average unit risk is 8.5 x 10~"
cancer deaths per pCi/L in water. This
corresponds to a lifetime average unit
risk of 6.3 x 10-» per pCi/L. This unit
risk excludes the risk of lung cancer
from inhaled radon gas, since this risk
is already included in the unit risk from
radon progeny. Based on the
population-weighted average radon
concentration of 213 pCi/L, the lifetime
average individual risk is 1.35 x 10~6
cancer deaths per person, and the
average annual individual risk is 1.8 x
10 ~8 cancer deaths per person per year.
Based on an exposed population of 88.1
million people, the annual population
risk is about 1.6 cancer deaths/year. The
uncertainty range around this estimate,
derived using Monte Carlo simulation
techniques, is about 1.0 to 2.7 cancer
deaths per year (USEPA 1999b).
4. Combined Fatal Cancer Risk
The best estimates of fatal cancer risks
to residents from ingesting radon in
water, inhalation of waterborne
progeny, and inhalation of radon gas are
presented in Table XII.7. As seen, EPA
estimates that an individual's combined
fatal cancer risk from lifetime
residential exposure to drinking water
containing 1 pCi/L of radon is slightly
less than 7 chances in 10 million (7 x
10~7), and that the population risk is
about 168 cancer deaths per year
(uncertainty range = 80 to 288 per year).
Of this risk, most (88 percent) is due to
inhalation of radon progeny, with 11
percent due to ingestion of radon gas,
and less than 1 percent due to
inhalation of radon gas.
TABLE XII.7.—SUMMARY OF UNIT RISK, INDIVIDUAL RISK AND POPULATION RISK ESTIMATES FOR RESIDENTIAL EXPOSURE
TO RADON IN COMMUNITY GROUNDWATER SUPPLIES
Exposure pathway
Radon Gas Ingestion
Radon Proqenv Inhalation
Lifetime unit risk
(fatal cancer cases per
person per pCi/L)
70 x 10~8
5.9x10-7
Annual individual risk
(fatal cancer cases per
person per year)
20 x 10~7
1.7 x 10-6
Annual pop-
ulation risk
(fatal cancer
cases per
year)
m
148
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TABLE XII.7.—SUMMARY OF UNIT RISK, INDIVIDUAL RISK AND POPULATION RISK ESTIMATES FOR RESIDENTIAL EXPOSURE
TO RADON IN COMMUNITY GROUNDWATER SUPPLIES—Continued
Exposure pathway
Total (credible bounds)
Lifetime unit risk
(fatal cancer cases per
person per pCi/L)
6.3x10-'
6.7x10-' (3.6x10-7 -
9.7x10-7)
Annual individual risk
(fatal cancer cases per
person per year)
1.8x10-8
1.9x10-6 (0.9 x10-6 -
3.3 x 10-s)
Annual pop-
ulation risk
(fatal cancer
cases per
year)
1.6
168
(80-288)
EPA believes that radon in
community groundwater water systems
also contributes exposure and risk to
people when they are outside the
residence (e.g., at school, work, etc.).
Although data are limited, a screening
level estimate suggests that this type of
exposure could be associated with about
36 additional lung cancer deaths per
year.
Request for Comment
EPA solicits public comments on its
assessment of risk from radon in
drinking water. In particular, EPA
requests comment and
recommendations on the best data
sources and best approaches to use for
evaluating ingestion and inhalation
exposures that occur for members of the
public (including both workers and non-
workers) at non-residential buildings
(e.g. restaurants, churches, schools,
offices, factories, etc).
E. Assessment by National Academy of
Sciences: Multimedia Approach to Risk
Reduction
The NAS report, "Risk Assessment of
Radon in Drinking Water," summarized
several assessments of possible
approaches relating reduction of radon
in indoor air from soil gas to reduction
of radon in drinking water. The NAS
Report provided useful perspectives on
multimedia mitigation issues that EPA
used in developing the proposed criteria
and guidance for multimedia mitigation
programs. The NAS Committee focused
on how the multimedia approach might
be applied at the community level and
defined a series of scenarios, assuming
that multimedia programs would be
implemented by public water systems.
The report may provide useful
perspectives of interest to public water
systems if their State does not develop
an EPA-approved MMM program.
For most of the scenarios, the
Committee chose primarily to focus on
how to compare the risks posed by
radon in indoor air from soil gas to the
risks from radon in drinking water in a
home in a local community. They
assessed the feasibility of different
activities based on costs, radon
concentrations, different assumptions
about risk reduction actions that might
be taken, and other factors.
Overall, the Committee suggested that
reduction of indoor radon can be an
alternative and more effective means of
reducing the overall risk from radon.
They went on to conclude that
mitigation of airborne radon to achieve
equal or greater radon risk reduction
"makes good sense from a public health
perspective." They also noted that non-
economic issues, such as equity
concerns, could factor into a
community's decision whether to
undertake a multimedia mitigation
program.
The Committee also discussed the
role of various indoor air mitigation
program strategies, or "mitigation
measures" as they are described in
SDWA. The Committee concluded that
an education and outreach program is
important to the success of indoor radon
risk reduction programs, but would not
in and of itself be sufficient to claim that
risk reduction took place. Based on an
assessment of several State indoor radon
programs, they found that States with
effective programs had several factors in
common in the implementation of their
programs. They concluded that the
effectiveness of these State programs
were the result of: (1) Promoting wide-
spread testing of homes, (2) conducting
radon awareness campaigns, (3)
providing public education on
mitigation, and (4) ensuring the
availability of qualified contractors to
test and mitigate homes.
These views are consistent with the
examples of indoor radon activities that
Congress set forth in the radon
provision in SDWA on which State
Multimedia Mitigation programs may
rely. These include "public education,
testing, training, technical assistance,
remediation grants and loans and
incentive programs, or other regulatory
or non-regulatory measures." These
measures also represent many of the
same strategies that are integral to the
current national and State radon
programs, as well as those outlined in
the 1988 Indoor Radon Abatement Act,
sections 304 to 307 (15 U.S.C. 2664-
2667).
EPA recognizes, as does the National
Academy of Sciences, that these
activities and strategies are important to
achieving public awareness and action
to reduce radon, but that these actions
are not in and of themselves actual risk
reduction. Therefore, EPA has
determined that State MMM plans will
need to set and track actual risk
reduction goals. However, the criteria
and guidance for States to use in
designing MMM program plans
provides extensive flexibility in
choosing strategies that reflect the needs
of individual States.
The Committee discussed the
effectiveness of various indoor radon
control technologies and recommended
that active sub-slab depressurization
techniques are most effective for
controlling radon in the mitigation of
elevated radon levels in existing
buildings and in the prevention of
elevated levels in new buildings.
(Active systems rely on mechanically-
driven techniques (powered fans) to
create a pressure gradient between the
soil and building interior and thus,
prevent radon entry.) The Committee
expressed concern over the adequacy of
the scientific basis for ensuring that
such methods can be used reliably as a
consistent outcome of normal design
and construction methods. The
Committee also noted the limited
amount of data available to quantify the
reduction in indoor radon levels
expected when such techniques were
used.
The Committee found that much of
the comparative data available on the
impact of the passive radon-resistant
new construction features is confined to
the impact of the passive thermal stack
on radon levels and not on the other
features of the passive radon-resistant
new construction system, such as
eliminating leakage paths, sealing utility
penetrations, and prescribing the extent
and quality of aggregate beneath the
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foundation. The Committee found that
the passive stack alone yielded
reductions in radon levels as great as
90%, that reductions in radon levels of
about 40% are more typical, and that
the effect of the passive stack may be
considerably less in slab-on-grade
houses that in houses with basements.
However, the Committee also stated that
the other features in the passive radon-
resistant new construction system
contribute to reducing radon levels. EPA
notes that there are substantial
difficulties in gathering good
comparative data on these other features
because of the significant variability of
radon potential across building sites,
even within a small area. In addition it
is impractical to test the same house
with and without radon resistant
features. However, based on the
Committee's discussion of the
contributions of these other features to
reducing radon levels, it is reasonable to
expect that passive systems as a whole
achieve greater reductions in radon than
the passive stack alone.
EPA agrees with the Committee's
perspective that active radon-reduction
systems, while slightly more expensive,
assure the greatest risk reduction in not
only the mitigation of existing homes,
but also in the construction of new
homes. EPA also agrees with the
Committee's perspective that more data
on passive new construction systems
would allow for more precise estimation
of average expected reductions in radon
levels in new homes from application of
passive radon-resistant new
construction techniques. However, EPA
believes there is sufficient data and
application experience to have a
reasonable assurance that the passive
techniques when used in new homes
reduce indoor radon levels by about
50% on average. Further, these
techniques have been adopted by the
home construction industry into
national model building codes and by
many State and local jurisdictions into
their building codes. EPA recommends
that new homes built with passive
radon-resistant new construction
features be tested after occupancy and if
elevated levels still exist, the passive
systems be converted to active ones. For
these reasons, EPA believes it is
appropriate to consider passive radon-
resistant new construction techniques
for new homes as one means of
achieving risk reduction through new
construction in multimedia mitigation
programs.
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
Section 1412(b)(13)(C) of the SDWA,
as amended, requires EPA to prepare a
Health Risk Reduction and Cost
Analysis (HRRCA) to be used to support
the development of the radon NPDWR.
EPA was to publish the HRRCA for
public comment and respond to
significant comments in this preamble.
EPA published the HRRCA in the
Federal Register on February 26, 1999
(64 FR 9559). Responses to significant
comments on the HRRCA are provided
in Section XIII.H.
The HRRCA addresses the
requirements established in Section
1412 (b) (3) (C) of the amended SDWA,
namely: (1) Quantifiable and non-
quantifiable health risk reduction
benefits for which there is a factual
basis in the rulemaking record to
conclude that such benefits are likely to
occur as the result of treatment to
comply with each level; (2) quantifiable
and non-quantifiable health risk
reduction benefits for which there is a
factual basis in the rulemaking record to
conclude that such benefits are likely to
occur from reductions in co-occurring
contaminants that may be attributed
solely to compliance with the MCL,
excluding benefits resulting from
compliance with other proposed or
promulgated regulations; (3)
quantifiable and non-quantifiable costs
for which there is a factual basis in the
rulemaking record to conclude that such
costs are likely to occur solely as a
result of compliance with the MCL,
including monitoring, treatment, and
other costs, and excluding costs
resulting from compliance with other
proposed or promulgated regulations;
(4) the incremental costs and benefits
associated with each alternative MCL
considered; (5) the effects of the
contaminant on the general population
and on groups within the general
population, such as infants, children,
pregnant women, the elderly,
individuals with a history of serious
illness, or other subpopulations that are
identified as likely to be at greater risk
of adverse health effects due to exposure
to contaminants in drinking water than
the general population; (6) any
increased health risk that may occur as
the result of compliance, including risks
associated with co-occurring
contaminants; and (7) other relevant
factors, including the quality and extent
of the information, the uncertainties in
the analysis, and factors with respect to
the degree and nature of the risk.
The HRRCA discusses the costs and
benefits associated with a variety of
radon levels. Summary tables and
figures are presented that characterize
aggregate costs and benefits, impacts on
affected entities, and tradeoffs between
risk reduction and compliance costs.
The HRRCA serves as a foundation for
the Regulatory Impact Analysis (RIA) for
this proposed rule.
B. Regulatory Impact Analysis and
Revised Health Risk Reduction and Cost
Analysis (HRRCA) for Radon
Under Executive Order 12866,
Regulatory Planning and Review, EPA
must estimate the costs and benefits of
the proposed radon rule in a Regulatory
Impact Analysis (RIA) and submit the
analysis to the Office of Management
and Budget (OMB) in conjunction with
the proposed rule. To comply with the
requirements of E.O. 12866, EPA has
prepared an RIA, a copy of which is
available in the public docket for this
proposed rulemaking. The revised
HRRCA is now included as part of the
RIA (USEPA 1999f). This section
provides a summary of the information
from the RIA for the proposed radon
rule.
1. Background: Radon Health Risks,
Occurrence, and Regulatory History
Radon is a naturally occurring volatile
gas formed from the normal radioactive
decay of uranium. It is colorless,
odorless, tasteless, chemically inert, and
radioactive. Uranium is present in small
amounts in most rocks and soil, where
it decays to other products including
radium, then to radon. Some of the
radon moves through air or water-filled
pores in the soil to the soil surface and
enters the air, and can enter buildings
through cracks and other holes in the
foundation. Some radon remains below
the surface and dissolves in ground
water (water that collects and flows
under the ground's surface). Due to their
very long half-life (the time required for
half of a given amount of a radionuclide
to decay), uranium and radium persist
in rock and soil.
Exposure to radon and its progeny is
believed to be associated with increased
risks of several kinds of cancer. When
radon or its progeny are inhaled, lung
cancer accounts for most of the total
incremental cancer risk. Ingestion of
radon in water is suspected of being
associated with increased risk of tumors
of several internal organs, primarily the
stomach. As required by the SDWA, as
amended, EPA arranged for the National
Academy of Sciences (NAS) to assess
the health risks of radon in drinking
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59321
water. The NAS released the pre-
publication draft of the "Report on the
Risks of Radon in Drinking Water,"
(NAS Report) in September 1998 and
published the Report in July 1999 (NAS
1999b). The analysis in this RIA uses
information from the 1999 NAS Report
(see Section XILC of this preamble). The
NAS Report represents a comprehensive
assessment of scientific data gathered to
date on radon in drinking water. The
report, in general, confirms earlier EPA
scientific conclusions and analyses of
radon in drinking water.
NAS estimated individual lifetime
unit fatal cancer risks associated with
exposure to radon from domestic water
use for ingestion and inhalation
pathways (Table XIII. 1). The results
show that inhalation of radon progeny
accounts for most (approximately 88
percent) of the individual risk
associated with domestic water use,
with almost all of the remainder (11
percent) resulting from directly
ingesting radon in drinking water.
Inhalation of radon progeny is
associated primarily with increased risk
of lung cancer, while ingestion exposure
is associated primarily with elevated
risk of stomach cancer.
TABLE XIII.1.—ESTIMATED RADON UNIT LIFETIME FATAL CANCER RISKS IN COMMUNITY WATER SYSTEMS
Exposure pathway
Inhalation of radon progeny1
Ingestion of radon1
Inhalation of radon gas2
Total
Cancer unit
risk per pCi/L
in water
5.9x10-'
7.0x10-8
63x10~9
6.7x10-''
Proportion of
total risk
(percent)
88
11
1
100
'Source: NAS 1998B.
a Source: Calculated by EPA from radiation dosimetry data and risk coefficients provided by NAS (NAS 1998B).
The NAS Report confirmed that
indoor air contamination arising from
soil gas typically accounts for the bulk
of total individual risk due to radon
exposure. Usually, most radon gas
enters indoor air by diffusion from soils
through basement walls or foundation
cracks or openings. Radon in domestic
water generally contributes a small
proportion of the total radon in indoor
air.
The NAS Report is one of the most
important inputs used by EPA in the
RIA. EPA has used the NAS's
assessment of the cancer risks from
radon in drinking water to estimate both
the health risks posed by existing levels
of radon in drinking water and also the
cancer deaths prevented by reducing
radon levels.
In updating key analyses and
developing the framework for the cost-
benefit analysis presented in the RIA,
EPA has consulted with a broad range
of stakeholders and technical experts.
Participants in a series of stakeholder
meetings held in 1997, 1998, and 1999
included representatives of public water
systems, State drinking water and
Indoor air programs. Tribal water
utilities and governments,
environmental and public health
groups, and other Federal agencies.
The RIA builds on several technical
components, including estimates of
radon occurrence in drinking water,
analytical methods for detecting and
measuring radon levels, and treatment
technologies. Extensive analyses of
these issues were undertaken by the
Agency in the course of previous
rulemaking efforts for radon and other
radionuclides. Using data provided by
stakeholders, and from published
literature, the EPA has updated these
technical analyses to take into account
the best currently available information
and to respond to comments on the
1991 proposed NPDWR for radon.
The analysis presented in the RIA
uses updated estimates of the number of
active public drinking water systems
obtained from EPA's Safe Drinking
Water Information System (SDWIS).
Treatment costs for the removal of radon
from drinking water have also been
updated. The RIA follows current EPA
policies with regard to the methods and
assumptions used in cost and benefit
assessment.
As part of the regulatory development
process, EPA has updated and refined
its analysis of radon occurrence patterns
in ground water supplies in the United
States (USEPA 19981). This new
analysis incorporates information from
the EPA's 1985 National Inorganic and
Radionuclides Survey (NIRS) of
approximately 1000 community ground
water systems throughout the United
States, along with supplemental data
provided by the States, water utilities,
and academic research. The new study
also addressed a number of issues raised
by public comments in the previous
occurrence analysis that accompanied
the 1991 proposed NPDWR, including
characterization of regional and
temporal variability in radon levels, and
the impact of sampling point for
monitoring compliance.
In general, radon levels in ground
water in the United States have been
found to be the highest in New England
and the Appalachian uplands of the
Middle Atlantic and Southeastern
States. There are also isolated areas in
the Rocky Mountains, California, Texas,
and the upper Midwest where radon
levels in ground water tend to be higher
than the United States average. The
lowest ground water radon levels tend
to be found in the Mississippi Valley,
lower Midwest, and Plains States. When
comparing radon levels in ground water
to radon levels in indoor air at the States
level, the distributions of radon
concentrations in indoor air do not
always mirror distributions of radon in
ground water.
2. Consideration of Regulatory
Alternatives
(a) Regulatory Approaches. The RIA
evaluates MCL options for radon in
ground water supplies of 100, 300, 500,
700, 1000, 2000, and 4000 pCi/L. As
Table VII. 1 in Section VII of the
preamble illustrates, the costs and
benefits increase as the radon level
decreases and the benefit-cost ratios are
very similar at each level. The RIA also
presents information on the costs and
benefits of implementing multimedia
mitigation (MMM) programs. The
scenarios evaluated are described in
detail in Sections 9 and 10 of the RIA
(USEPA 1999f). Based on the analysis
shown in the report, the selected
regulatory alternative discussed next
has a significant multimedia mitigation
component. For more information on
this analysis, please refer to the RIA.
(b) Selected Regulatory Alternatives.
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
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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:
(i) Requirements for Small Systems
Serving 10,000 People or Less. The EPA
is proposing that small CWSs 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
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 cost-
effective way to reduce radon risk than
compliance with the MCL. (While EPA
believes that the MMM approach is
preferable for small systems in a non-
MMM 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.
(ii) 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 CWS develops
and implements a MMM program
meeting the four regulatory
requirements, in which case large
systems may comply with the AMCL of
4,OOOpCi/L. CWSs developing their own
MMM plans will be required to submit
these plans to their State for approval.
(c) Background on the Selection of the
MCL and AMCL. For a description of
EPA's process in selecting the MCL and
AMCL, see Section VII.D of today's
preamble.
C. Baseline Analysis
Data and assumptions used in
establishing baselines for the
comparison of costs and benefits are
presented in the next section. While the
rule as proposed does not require 100
percent compliance with an MCL, an
analysis of these full compliance
scenarios are required by the SDWA, as
amended, and were an important feature
in the development of the NPDWR for
radon.
1. Industry Profile
Radon is found at appreciable levels
only in systems that obtain water from
ground water sources. Thus, only
ground water systems would be affected
by the proposed rule. The following
discussion addresses various
characteristics of community ground
water systems that were used in the
assessment of regulatory costs and
benefits. Table XIII.2 shows the
estimated number of community ground
water systems in the United States. This
data originally came from EPA's Safe
Drinking Water Information System
(SDWIS) and are summarized in EPA's
Drinking Water Baseline Handbook
(USEPA, 1999c). EPA estimates that
there were 43,908 community ground
water systems active in December 1997
when the SDWIS data were evaluated.
Approximately 96.5 percent of the
systems serve fewer than 10,000
customers, and thus fit EPA's definition
of a "small" system (see 63 FR 44512 at
44524-44525, August 19, 1998).
Privately-owned systems comprise the
bulk of the smaller size categories,
whereas most larger systems are
publicly owned.
TABLE XIII.2.—NUMBER OF COMMUNITY GROUND WATER SYSTEMS IN THE UNITED STATES 1
Primary source/
ownership
Total
Public
Private
Purchased-Public ..
Purchased-Private
Other
System size category
25-100
14,232
1,202
12,361
114
171
384
101-500
15,070
4,104
9,776
427
347
416
501-
1,000
4,739
2,574
1,705
265
101
94
1,001-
3,301
5,726
3,792
1,531
272
79
52
3,301-
10,000
2,489
1,916
459
84
13
17
10,001-
50,000
1,282
997
243
36
3
3
50,001-
100,000
139
113
24
1
1
0
100,001-
1,000,000
70
52
14
4
0
0
>1, 000,000
2
2
0
0
0
0
Total
43,908
14,764
26,252
1,203
718
971
1 Source: USEPA 1999c.
In addition to the number of affected
systems, the total number of sources
(wells) is an important determinant of
potential radon mitigation costs. Larger
systems tend to have larger numbers of
sources than small ones, and it has been
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59323
conservatively assumed in the
mitigation cost analysis that each source
out of compliance with the MCL or
AMCL would need to install control
equipment.
Table XIII.3 summarizes the estimated
number of wells per ground water
system. Both the number of wells and
the variability in the number of wells
increases with the number of customers
served. These characteristics of
community ground water sources are
included in the mitigation cost analysis
discussed in Section 7 of the RIA
(USEPA 1999f).
2. Baseline Assumptions
In addition to the characteristics of
the ground water suppliers, other
important "baseline" assumptions were
made that affect the estimates of
potential costs and benefits of radon
mitigation. Two of the most important
assumptions relate to the distribution of
radon in ground water sources and the
technologies that are currently in place
for ground water systems to control
radon and other pollutants.
As noted in Section 3 of the RIA
(USEPA 1999f), EPA has recently
completed an analysis of the occurrence
patterns of radon in groundwater
supplies in the United States (USEPA
1999g). This analysis used the MRS and
other data sources to estimate national
distributions of groundwater radon
levels in community systems of various
sizes. The results of that analysis are
summarized in Table XIII.4. These
distributions are used to calculate
baseline individual and population
risks, and to predict the proportions of
systems of various sizes that will require
radon mitigation.
TABLE XIII.3.—ESTIMATED AVERAGE NUMBER OF WELLS PER GROUNDWATER SYSTEM 1
Average Number of Wells
(Confidence Interval) ....
System size category
25-100
1.5(0.2)
101-500
2.0 (0.2)
501-1,000
2.3 (0.2)
1001-3,301
3.1 (0.3)
3,301-
10,000
4.6(1.1)
10,001-
50,000
9.8(1.8)
50,001-
100,000
16.1 (2.2)
100,001-
1,000,000
49.9 (12.7)
'Source: USEPA 1999c.
TABLE XIII.4.—DISTRIBUTION OF RADON LEVELS IN U.S. GROUNDWATER SOURCES
Statistic
Geometric Mean, pCi/L
Geometric Standard Deviation, pCi/L
Arithmetic Mean
Population served
25-100
312
3.04
578
101-500
259
3.31
528
501-3,300
122
3.22
240
3,301-10,000
124
2.29
175
>1 0,000
132
2.31
187
The costs of radon mitigation are affected to some extent by the treatment technologies that are currently in place
to mitigate radon and other pollutants, and by the existence of pre- and post-treatment technologies that affect the
costs of mitigation. EPA has conducted an extensive analysis of water treatment technologies currently in use by ground-
water systems. Table XIII.5 shows the proportions of ground water systems with specific technologies already in place,
broken down by system size (population served). Many ground water systems currently employ disinfection, aeration,
or iron/manganese removal technologies. This distribution of pre-existing technologies serves as the baseline against
which water treatment costs are measured. For example, costs of disinfection are attributed to the radon rule only
for the estimated proportion of systems that would have to install disinfection as a post-treatment because they do
not already disinfect. The cost analysis assumes that any system affected by the rule will continue to employ pre-
existing radon treatment technology and pre- and post-treatment technologies in their efforts to comply with the rule.
Where pre- or post-treatment technologies are already in place it is assumed that compliance with the radon rule
will not require any upgrade or change in the pre- or post-treatment technologies. Therefore, no incremental cost is
attributed to pre- or post-treatment technologies. This may underestimate costs if pre- or post-treatment technologies
need to be changed (e.g., a need for additional chlorination after the installation of packed tower aeration). The potential
magnitude of this cost underestimation is not known, but is likely to be a very small fraction of total treatment costs.
Table XIII.5.—Estimated Proportions of Groundwater Systems With Water Treatment Technologies Already in Place
(Percent)1
System Size (Population Served)
vvcutii imauiiuiu
technologies in place
Fe/Mn removal & aeration
& disinfection
Fe/Mn removal & aeration
Fe/Mn removal & disinfec-
tion
Fe/Mn removal
Aeration & disinfection
only
Aeration only
Disinfection onlv
25-100
0.4
0
2.1
1.9
0.9
0.8
49.6
101-500
0.2
0.1
5.1
1.5
3.2
1
68.2
501-1,000
1.2
0.2
8.3
1.5
9.8
1.8
65
1,001-3,300
0.6
0.1
3
1
13.7
2.9
65
3,301-
10,000
2.9
0.4
7.8
1.1
20.9
2.9
56.3
10,001-
50,000
2.2
0.1
7.4
0.4
19.7
1
66
50,001-
100,000
3.1
0.4
9.7
1.1
18.6
2.1
58.3
100,001
1,000,000
2
0.1
6.8
0.2
19.9
0.6
68.3
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Federal Register/Vol. 64, No. 211/Tuesday, November 2, 1999/Proposed Rules
Table X1II.5.—Estimated Proportions of Groundwater Systems With Water Treatment Technologies Already in Place
(Percent)1—Continued
System Size (Population Served)
vvaier ireaimem
technologies in place
None
25-100
44.3
101-500
20.7
501-1,000
12.2
1,001-3,300
13.7
3,301-
10,000
7.7
10,001-
50,000
3.2
50,001-
100,000
6.7
100,001
1,000,000
2.1
1. Source: EPA analysis of data from the Community Water System Survey (CWSS), 1997, and Safe Drinking Water Information System
(SDWIS), 1998.
The treatment baseline assumptions
shown in Table XIII. 5 were used in the
initial analysis for the development of
the NPDWR for radon. These
assumptions were used to establish the
costs of 100 percent compliance with an
MCL. Another analysis, which portrays
the costs of the rule as recommended in
this proposed rulemaking, is provided
in the results section of this summary
and also in Section 9 of the RIA.
D. Benefits Analysis
11. Quantifiable and Non-Quantifiable
Health Benefits
The quantifiable health benefits of
reducing radon exposures in drinking
water are attributable to the reduced
incidence of fatal and non-fatal cancers,
primarily of the lung and stomach.
Table XIII. 6 shows the health risk
reductions (number of fatal and non-
fatal cancers avoided) and the residual
health risk (number of remaining cancer
cases) at various radon in water levels.
TABLE XIII.6.—RESIDUAL CANCER RISK AND RISK REDUCTION FROM REDUCING RADON IN DRINKING WATER
Radon Level
(pCi/L in water)
(Baseline) .
400022 .
2 000
1,000
700
500 .
300 .
100
Residual ratal
cancer risk
(cases per
year)
168
165
160
150
141
130
106
46.8
Residual
non-fatal
cancer risk
(cases per
year)
9.7
9.5
9.4
8.8
8.3
7.6
6.1
2.8
Risk reduc-
tion
(fatal cancers
avoided per
year)1
0
2.9
7.3
17.8
26.1
37.6
62.0
120
Risk reduc-
tion
(non-fatal
cancers
avoided per
year)1
0
0.2
0.4
1.1
1.5
2.2
3.6
7.0
Notes:
1 Risk reductions and residual risk estimates are slightly inconsistent due to rounding.
24000 pCi/L is equivalent to the AMCL estimated by the NAS based on SDWA provisions of Section 1412(b)(13).
Since preparing the prepublication
edition of the NAS Report, the NAS has
reviewed and slightly revised their unit
risk estimates. EPA uses these updated
unit risk estimates in calculating the
baseline risks, health risk reductions,
and residual risks. Under baseline
assumptions (no control of radon
exposure), approximately 168 fatal
cancers and 9.7 non-fatal cancers per
year are associated with radon
exposures through CWSs. At a radon
level of 4,000 pCi/L, approximately 2.9
fatal cancers and 0.2 non-fatal cancers
per year are prevented. At 300 pCi/L,
approximately 62.0 fatal cancers and 3.6
non-fatal cancers are prevented each
year.
The Agency has developed monetized
estimates of the health benefits
associated with the risk reductions from
radon exposures. The SDWA, as
amended, requires that a cost-benefit
analysis be conducted for each NPDWR,
and places a high priority on better
analysis to support rulemaking. The
Agency is interested in refining its
approach to both the cost and benefit
analysis, and in particular recognizes
that there are different approaches to
monetizing health benefits. In the past,
the Agency has presented benefits as
cost per life saved, as in Table XIII.7.
The costs of reducing radon to various
levels, assuming 100 percent
compliance with an MCL, are
summarized in Table XIII.7, which
shows that, as expected, aggregate radon
mitigation costs increase with
decreasing radon levels. For CWSs, the
costs per system do not vary
substantially across the different radon
levels evaluated. This is because the
menu of mitigation technologies for
systems with various influent radon
levels remains relatively constant and
are not sensitive to percent removal.
TABLE XIII.7.—ESTIMATED ANNUALIZED NATIONAL COSTS OF REDUCING RADON EXPOSURES
[IMillion, 1997]
Radon level (pCi/L)
4000 1
2000
Central tend-
ency estimate
of annualized
costs2
34.5
61.1
Total
annualized na-
tional costs3
43.1
69.7
Total cost per
fatal cancer
case avoided
14.9
9.5
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59325
TABLE XIII.7.—ESTIMATED ANNUALIZED NATIONAL COSTS OF REDUCING RADON EXPOSURES—Continued
[$MilIion, 1997]
Radon level (pCi/L)
•(000 .„
700 ,
500
300
100
Central tend-
ency estimate
of annualized
costs 2
121.9
176.8
248.8
399.1
807.6
Total
annualized na-
tional costs3
130.5
185.4
257.4
407.6
816.2
Total cost per
fatal cancer
case avoided
7.3
7.1
6.8
6.6
6.8
14000 pCi/L Is equivalent to the AMCL estimated by the NAS based on SDWA requirements of Section 1412(b)(13).
8 Costs include treatment, monitoring, and O&M costs only.
3 Costs include treatment, monitoring, O&M, recordkeeping, reporting, and state costs for administration of water programs.
An alternative approach presented
here for consideration as one measure of
potential benefits is the monetary value
of a statistical life (VSL) applied to each
fatal cancer avoided. Since this
approach is relatively new to the
development of NPDWRs. EPA is
Interested in comments on these
alternative approaches to valuing
benefits, and will have to weigh the
value of these approaches for future use.
Estimating the VSL involves inferring
Individuals' implicit tradeoffs between
small changes in mortality risk and
monetary compensation. In the HRRCA,
a central tendency estimate of $5.8
million (1997S) is used in the monetary
benefits calculations. This figure is
determined from the VSL estimates in
26 studies reviewed in EPA's recent
draft guidance on benefits assessment
(USEPA 1998e). which is currently
under review by the Agency's Science
Advisory Board (SAB) and the Office of
Management and Budget (OMB).
It is important to recognize the
limitations of existing VSL estimates
and to consider whether factors such as
differences in the demographic
characteristics of the populations and
differences in the nature of the risks
being valued have a significant impact
on the value of mortality risk reduction
benefits. Also, medical care or lost-time
costs are not separately included in the
benefits estimate for fatal cancers, since
It is assumed that these costs are
captured in the VSL for fatal cancers.
For non-fatal cancers, willingness to
pay (WTP) data to avoid chronic
bronchitis is used as a surrogate to
estimate the WTP to avoid non-fatal
lung and stomach cancers. The use of
such WTP estimates is supported in the
SDWA, as amended, at Section
1412(b)(3)(C)(iii): "The Administrator
may identify valid approaches for the
measurement and valuation of benefits
under this subparagraph, including
approaches to identify consumer
willingness to pay for reductions in
health risks from drinking water
contaminants."
A WTP central tendency estimate of
$536,000 is used to monetize the
benefits of avoiding non-fatal cancers
(Viscusi et al. 1991). The combined fatal
and non-fatal health benefits are
summarized in Table XIII.8. The annual
health benefits range from $ 17.0 million
for a radon level of 4000 pCi/L to $702
million at 100 pCi/L.
TABLE XIII.8.—ESTIMATED MONETIZED
HEALTH BENEFITS FROM REDUCING
RADON IN DRINKING WATER
Radon level (pCi/L)
4.0002
2,000
1 000
700
500
300
100
Monetized
health bene-
fits, central
tendency
(annualized,
$millions,
1997)1
17.0
42.7
103
152
219
362
702
Notes:
11ncludes contributions from fatal and non-
fatal cancers, estimated using central tend-
ency estimates of the VSL of $5.8 million
(1997$), and a WTP to avoid non-fatal can-
cers of $536,000 (1997$).
2 4000 pCi/L is equivalent to the AMCL esti-
mated by the NAS based on SDWA provisions
ofSection1412(b)(13).
Reductions in radon exposures might
also be associated with non-quantifiable
benefits. EPA has identified several
potential non-quantifiable benefits
associated with regulating radon in
drinking water. These benefits may
include any customer peace of mind
from knowing drinking water has been
treated for radon. In addition, if
chlorination is added to the process of
treating radon via aeration, arsenic pre-
oxidation will be facilitated. Neither
chlorination nor aeration will remove
arsenic, but chlorination will facilitate
conversion of Arsenic (III) to Arsenic
(V). Arsenic (V) is a less soluble form
that can be better removed by arsenic
removal technologies. In terms of
reducing radon exposures in indoor air,
it has also been suggested that provision
of information to households on the
risks of radon in indoor air and
available options to reduce exposure
may be a non-quantifiable benefit that
can be attributed to some components of
a MMM program. Providing such
information might allow households to
make more informed choices than they
would have in the absence of an MMM
program about the need for risk
reduction given their specific
circumstances and concerns. In the case
of the proposed radon rule, it is not
likely that accounting for these non-
quantifiable benefits would significantly
alter the overall assessment.
The benefits calculated for this
proposal are assumed to begin to accrue
on the effective date of the rule and are
based on a calculation referred to as the
"value of a statistical life" (VSL),
currently estimated at $5.8 million. The
VSL is an average estimate derived from
a set of 26 studies estimating what
people are willing to pay to avoid the
risk of premature mortality. Most of
these studies examine willingness to
pay in the context of voluntary
acceptance of higher risks of immediate
accidental death in the workplace in
exchange for higher wages. This value is
sensitive to differences in population
characteristics and perception of risks
being valued.
For the present rulemaking analysis,
which evaluates reduction in premature
mortality due to carcinogen exposure,
some commenters have argued that the
Agency should consider an assumed
time lag or latency period in these
calculations. Latency refers to the
difference between the time of initial
exposure to environmental carcinogens
and the onset of any resulting cancer.
Use of such an approach might reduce
significantly the present value estimate.
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The BEIR VI model and U.S. vital
statistics, on which the estimate of lung
cancers avoided is based, imply a
probability distribution of latency
periods between inhalation exposure to
radon and increased probability of
cancer death. EPA is interested in
receiving comments on the extent to
which the presentation of more detailed
information on the timing of cancer risk
reductions would be useful in
evaluating the benefits of the proposed
rule.
Latency is one of a number of
adjustments or factors that are related to
an evaluation of potential benefits
associated with this rule, how those
benefits are calculated, and when those
economic benefits occur. Other factors
which may influence the estimate of
economic benefits associated with
avoided cancer fatalities include (1) A
possible "cancer premium" (i.e., the
additional value or sum that people may
be willing to pay to avoid the
experiences of dread, pain and
suffering, and diminished quality of life
associated with cancer-related illness
and ultimate fatality); (2) the
willingness of people to pay more over
time to avoid mortality risk as their
income rises; (3) a possible premium for
accepting involuntary risks as opposed
to voluntary assumed risks; (4) the
greater risk aversion of the general
population compared to the workers in
the wage-risk valuation studies; (5)
"altruism" or the willingness of people
to pay more to reduce risk in other
sectors of the population; and (6) a
consideration of health status and life
years remaining at the time of premature
mortality. Use of certain of these factors
may significantly increase the present
value estimate. EPA therefore believes
that adjustments should be considered
simultaneously. The Agency also
believes that there is currently neither a
clear consensus among economists
about how to simultaneously analyze
each of these adjustments nor is there
adequate empirical data to support
definitive quantitative estimates for all
potentially significant adjustment
factors. As a result, the primary
estimates of economic benefits
presented in the analysis of this rule
rely on the unadjusted $5.8 million
estimate. However, EPA solicits
comment on whether and how to
conduct these potential adjustments to
economic benefits estimates together
with any rationale or supporting data
commenters wish to offer. Because of
the complexity of these issues, EPA will
ask the Science Advisory Board (SAB)
to conduct a review of these benefits
transfer issues associated with economic
valuation of adjustments in mortality
risks. In its analysis of the final rule,
EPA will attempt to develop and present
an analysis and estimate of the latency
structure and associated benefits
transfer issues outlined previously
consistent with the recommendations of
the SAB and subject to resolution of any
technical limitations of the data and
models.
E. Cost Analysis
1. Total National Costs of Compliance
with MCL Options
Table XIII. 9 summarizes the estimates
of total national costs of compliance
with the range of potential MCLs
considered. The table is divided into
two major groupings; the first grouping
displays the estimated costs to systems
and the second grouping displays the
estimated costs to States. State costs,
presented in Table XIII.9, were
developed as part of the analyses to
comply with the Unfunded Mandates
Reform Act (UMRA) and also the
Paperwork Reduction Act (PRA).
Additional information on State costs is
provided in Section 8 of the RIA and
also in Section VIII of this preamble.
TABLE XIII.9.—SUMMARY OF ESTIMATED COSTS UNDER THE PROPOSED RADON RULE ASSUMING 100% COMPLIANCE
WITH AN MCL OF 300 PCI/L
[$ Millions]1
3 percent cost
of capital
7 percent cost
of capital
10 percent
cost
of capital
Costs to Water Systems
Total Capital
Costs (2
0 years
undiscounted) . •
2,463
2,463
2,463
Annual Costs
Annualized Capital • • •
Annual O&M *
Total Annual Costs to Water Systems3
165.6
152.4
318.0
14.1
6.1
338.2
232.5
152.4
385.0
14.1
6.1
405.1
289.4
152.4
441.8
14.1
6.1
461.6
Costs to States
Administration of Water Programs •
Total Annual Costs of Compliance4
2.5
2.5
340.6
2.5
2.5
407.6
2.5
2.5
464.4
1. Assumes no MMM program implementation costs (e.g., all systems comply with 300 pCi/L).
2. Figure represents average annual burden over 20 years.
3. Costs include treatment, monitoring, O&M, recordkeeping, and reporting costs to water systems.
4. Totals have been rounded. Costs include treatment, monitoring, O&M, recordkeeping, reporting, and state costs for administration of water
programs.
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59327
2. Quantifiable and Non-quantifiable
Costs
The capital and operating and
maintenance (O&M) costs of mitigating
radon in Community Water Systems
(CWSs) were estimated for each of the
radon levels evaluated. The costs of
reducing radon in community ground
water to specific target levels were
calculated using the cost curves
discussed in Section 7.5 and the matrix
of treatment options presented in
Section 7.6 of the RIA. For each radon
level and system size stratum, the
number of systems that need to reduce
radon levels by up to 50 percent. 80
percent and 99 percent were calculated.
Then, the cost curves for the
distributions of technologies dictated by
the treatment matrix were applied to the
appropriate proportions of the systems.
Capital and O&M costs were then
calculated for each system, based on
typical estimated design and average
flow rates. These flow rates were
calculated on spreadsheets using
equations from EPA's Baseline
Handbook (USEPA 1999e). The
equations and parameter values relating
system size to flow rates are presented
in Appendix C of the RIA. The
technologies addressed in the cost
estimation included a number of
aeration and granular activated carbon
(GAC) technologies described in Section
7.2 of the RIA, as well as storage,
regionalization, and disinfection as a
post-treatment. To estimate costs, water
systems were assumed, with a few
exceptions to simulate site-specific
problems, to select the technology that
could reduce radon to the selected target
level at the lowest cost. CWSs were also
assumed to treat separately at every
source from which water was obtained
and delivered into the distribution
system.
EPA has attempted to note potential
non-quantifiable benefits when the
Agency believes they might occur, as in
the case of peace-of-mind benefits from
radon reduction. The Agency recognizes
that there may also be non-quantifiable
disbenefits, such as anxiety on the part
of those near aeration plants or those
who find out that their radon levels are
high. It is not possible to determine
whether the net results of such
psychological effects would be positive
or negative. The inclusion of non-
quantifiable benefits and costs in this
analysis are not likely to alter the
overall results of the benefit-cost
analysis for the proposed radon rule.
F. Economic Impact Analysis
A summary analysis of the impacts on
small entities is shown in Section XIV.B
of this preamble (Regulatory Flexibility
Act). An analysis of the impacts on
State, local, and tribal governments is
shown in Section XIV. C (Unfunded
Mandates Reform Act). For information
on how this proposed rulemaking may
impact Indian tribal governments, see
Section XIV.I of today's preamble.
Information on the types of information
that States will be required to collect, as
well as EPA's estimate of the burden
and reporting requirements for this
proposed rulemaking, is shown in
Section XIV. D (Paperwork Reduction
Act). EPA's assessment of the impacts
that this proposed rulemaking may have
on low-income and minority
populations, as well as any potential
concerns regarding children's health,
are shown in Section XIV.F
(Environmental Justice) and Section
XIV. G (Protection of Children from
Environmental Health Risks and Safety
Risks) of today's preamble.
G. Weighing the Benefits and Costs
1. Incremental Costs and Benefits of
Radon Removal
TABLE XIII.10.—ESTIMATES OF THE ANNUAL INCREMENTAL RISK REDUCTION, COSTS, AND BENEFITS OF REDUCING
RADON IN DRINKING WATER ASSUMING 100% COMPLIANCE WITH AN MCL
[$ Millions 1997]
Incremental Risk Reduction, Fatal Can-
cers Avoided Per Year
Incremental Risk Reduction, Non-Fatal
Cancers Avoided Per Year . .
Annual Incremental Monetized Benefits,
S Million Per Year
Annual Incremental Radon Mitigation
Costs, § Million Per Year2 ... .
Radon Level, pCi/L
40001
2.9
0.2
17.0
34.5
2000
4.4
0.3
25.7
26.6
1000
10.5
0.6
61.0
60.8
700
8.4
0.4
48.7
54.9
500
11.5
0.8
67.1
72.0
300
24.4
1.3
142
150.3
100
58.4
3.5
341
408.5
14000 pCW- is equivalent to the AMCL estimated by the NAS based on SDWA requirements of Section 1412(b)(13)
a Costs include treatment, monitoring, and O&M costs only.
2. Impacts on Households
The cost impact of reducing radon in drinking water at the household level was also assessed. As expected, costs
per household increase as system size decreases as shown in Table XIII. 11.
TABLE Xlll.11.—ANNUAL COSTS PER HOUSEHOLD FOR COMMUNITY WATER SYSTEMS TO TREAT TO VARIOUS RADON
LEVELS1
[$, 1997]
Radon level (pCi/L)
WS (25-
100)
VVS (101-
500)
VS (501-
3300)
S (3301-
10K)
M (10,001-
100K)
L(>100K)
Households Served by PUBLIC Systems Above Radon Level by Population Served
40002
2000
1000
700 ,.
500
2565
259 0
262 5
264 4
266.3
91 0
92 g
948
96 0
97.1
22 7
PT ^
">&. fi
pc p
25.9
143
•\A Q
-\ C A
•ICQ
1fi4
fi *>
7 1
8C
mfi
A R
ft 1
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Federal Register/Vol. 64, No. 211/Tuesday, November 2, 1999/Proposed Rules
TABLE Xlll.11.—ANNUAL COSTS PER HOUSEHOLD FOR COMMUNITY WATER SYSTEMS TO TREAT TO VARIOUS RADON
LEVELS 1—Continued
[$, 1997]
Radon level (pCi/L)
3QO
100
VVS (25-
100)
269.5
278.8
VVS (101-
500)
99.3
107.1
VS (501-
3300)
26.9
29.1
S (3301-
10K)
17.4
20.1
M (10,001-
100K)
12.4
16.2
L (> 100K)
9.5
12.8
Households Served by PRIVATE Systems Above Radon Level by Population Served
40Q02
2000
-|000
700
500 •
300
100
372.4
375.8
380.5
383.1
385.6
389.8
401.5
141.1
143.7
146.3
147.8
149.4
152.2
, 162.4
30.3
31.2
32.6
33.4
34.2
35.5
37.9
22.8
23.7
24.7
25.4
26.2
27.7
32.1
6.6
7.5
9.1
10.1
11.2
13.1
17.1
4.4
5.1
6.3
7.1
7.9
9.4
12.6
' Reflects total household costs for systems to treat down to these levels. Because EPA expects that most systems will comply with the AMCL/
MCL most systems will not incur these household costs.
2 4000 pCi/L is equivalent to the AMCL estimated by the NAS based on SDWA requirements of Section 1412(b)(13).
Costs to households are higher for
households served by smaller systems
than larger systems for two reasons.
First, smaller systems serve far fewer
households than larger systems and,
consequently, each household must bear
a greater percentage share of the capital
and O&M costs. Second, smaller
systems tend to have higher influent
radon concentrations that, on a per-
capita or per-household basis, require
more expensive treatment methods (e.g.,
one that has an 85 percent removal
efficiency rather than 50 percent) to
achieve the applicable radon level.
To further evaluate the impacts of
these household costs, the costs per
household were compared to median
household income data for each system-
size category. The results of this
calculation, presented in Table XIII. 12
for public and private systems, indicate
a household's likely share of average
incremental costs in terms of the
median income. Actual costs for
individual households will reflect
higher or lower income shares
depending on whether they are above or
below the median household income
(approximately $30,000 per year) and
whether the water system incurs above
average or below average costs for
installing treatment. For all system sizes
but very very small private systems,
average household costs as a percentage
of median household income are less
than one percent for households served
by either public or private systems.
Average impacts exceed one percent
only for households served by very very
small private systems, which are
expected to face average impacts of 1.12
percent at the 4,000 pCi/1 level and 1.35
percent at the 300 pCi/1 level and for
households served by very very small
public systems at the 300 pCi/1 level,
whose average costs barely exceed one
percent. Similar to the average cost per
household results on which they are
based, average household impacts
exhibit little variability across radon
levels.
TABLE XIII. 12.—PER HOUSEHOLD IMPACT BY COMMUNITY GROUNDWATER SYSTEMS AS A PERCENTAGE OF MEDIAN
HOUSEHOLD INCOME
[Percent]
Radon level, pCi/L
4000 1
2000
1000
700
500
300
100
Average Impact to Households Served by Public Sys-
tems Exceeding Radon Levels
VVS
(25-
100)
0.86
0.92
0.96
0.98
1.00
1.05
1.17
VVS
(101-
500)
0.30
0.36
0.38
0.38
0.39
0.40
0.44
VS
0.13
0.12
0.13
0.13
0.13
0.14
0.15
S
0.06
0.05
0.05
0.06
0.06
0.06
0.07
M
0.03
0.02
0.02
0.03
0.03
0.03
0.05
L
•0.02
0.01
0.01
0.02
0.02
0.02
0.03
Average Impact to Households Served by Private Sys-
tems Exceeding Radon Levels
WS
(25-
100)
1.12
1.19
1.24
1.27
1.30
1.35
1.51
VVS
(101-
500)
0.35
0.42
0.44
0.45
0.45
0.47
0.51
VS
0.16
0.16
0.16
0.17
0.17
0.18
0.19
S
0.07
0.09
0.09
0.09
0.09
0.10
0.12
M
0.04
0.02
0.03
0.03
0.03
0.04
0.05
L
0.02
0.01
0.01
0.01
0.01
0.02
0.02
14000 pCi/L is equivalent to the AMCL estimated by the NAS based on SDWA requirements of Section 1412(b)(13).
3. Summary of Annual Costs and
Benefits
Table XIII. 13 reveals that at a radon
level of 4000 pCi/L (equivalent to the
AMCL estimated in the NAS Report),
annual costs of 100 percent compliance
with an MCL are approximately twice
the annual monetized benefits. For
radon levels of 1000 pCi/L to 300 pCi/
L, the central tendency estimates of
annual costs are above the central
tendency estimates of the monetized
benefits.
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Federal Register/Vol. 64, No. 211/Tuesday, November 2, 1999/Proposed Rules
59329
TABLE XIII.13.—ESTIMATED NATIONAL ANNUAL COSTS AND BENEFITS 1 OF REDUCING RADON EXPOSURES ASSUMING
100% COMPLIANCE WITH AN MCL—CENTRAL TENDENCY ESTIMATE
[$ Millions, 1997]
Radon level
(pCi/L)
4000*
2000
1000
700
500
300
100
Annualized
treatment
costs 2
345
61 1
121 9
176 8
248 8
399 1
807 6
Total
annualized
costs 3
43 1
69 7
130 5
185 4
257 4
407 6
816 2
Cost per fatal
cancer avoid-
ed
14 9
9 5
7 3
7 •(
6 8
6 6
6 8
Annual mone-
tized benefits
17 n
42 7
1m
1"i9
219
"3R9
7O9
Notes:
1 Benefits are calculated for stomach and lung cancer assuming that risk reduction begins immediately. Estimates assume a $5.8 million value
of a statistical life and willingness to pay of $536,000 for non-fatal cancers.
8 Costs are annualized over twenty years using a discount rate of seven percent. Costs include treatment, monitoring, and O&M costs.
3 Costs include treatment, monitoring, O&M, recordkeeping, reporting, and state costs for administration of water programs.
•*4000 pCi/L is equivalent to the AMCL estimated by the NAS based on SDWA requirements of Section 1412(b)(13).
Because the costs of compliance with an MCL for small systems outweigh the benefits at each radon level (Table
XIII. 14), the MMM option was recommended for small systems to alleviate some of the financial burden to these
systems and the households they serve and to realize equivalent or greater benefits at much lower costs. The results
of the benefit-cost analyses for MMM implementation scenarios are shown at the end of this section and also in Section
9 of the RIA.
TABLE XIII.14.— ESTIMATED ANNUAL COSTS AND BENEFITS FOR 100% COMPLIANCE WITH AN MCL BY SYSTEM SIZE
[$Millions, 1997]
Radon level (pCi/l)
4000
2000
1000
700
500
300
100
Parameter1
Benefits
Costs
Benefits
Costs
Benefits
Costs
Benefits
Costs
Benefits
Costs
Benefits
Costs
Benefits
Costs
System size
25-100
0.16
7.8
0.41
13.2
1.0
23.1
1.5
30.6
2.1
39.4
3.5
55.6
7.2
93.4
101-500
0.79
14.3
2.0
22.7
4.8
36.5
7.1
46.5
10.2
57.9
16.9
79.3
32.7
134
501-3300
2.7
6.3
6.8
11.6
16.3
24.7
24.1
36.3
34.7
50.8
57.3
78.8
111
147
3301-10,000
2.8
2.9
6.9
5.7
16.7
13.4
24.6
21.1
35.4
32.0
58.6
56.1
113
122
1 0,001-1 OOK
7.0
2.7
17.7
6.3
42.6
18.9
62.9
32.8
90.6
53.0
150
99.3
290
238
>100K
3.6
0.5
9.0
1.6
21.6
5.3
31.9
9.5
45.9
15.6
75.9
26.9
147
73.5
1 Costs do not include recordkeeping, reporting, or state costs for administration of water programs. Recordkeeping and reporting costs are es-
timated at $6.1 million for all system sizes and State administration costs for water programs are estimated at $2.5 million.
Total costs to public and private water systems, by size, were also evaluated in the RIA. Table XIII. 15 presents
the total annualized costs for public and private systems by system size category for all radon levels evaluated in
the RIA. The costs are comparable for public and private systems across system sizes for all options. This pattern
may be due in large part to the limited number of treatment options assumed to be available to either public or
private systems in mitigating radon.
TABLE XIII.15.—AVERAGE ANNUAL COST PER SYSTEM
[$Thousands, 1997]
Radon Level
(pCW)
4000
2000
1000
700
500
300
100
Average costs to public systems exceeding radon levels
WS(25-
100)
8.2
8.3
8.4
8.5
8.5
8.6
8.9
VVS
(101-
500)
12.4
12.6
12.9
13.0
13.2
13.5
14.6
VS
18.5
19.1
26.6
27.2
27.8
28.8
31.0
S
49.3
51.3
60.1
61.9
63.7
67.4
77.2
M
82.3
94.1
115.9
129.0
143.2
167.1
219.1
L
484.9
560.7
693.4
758.3
847.8
1000.4
1345.3
Average costs to private systems exceeding radon levels
VVS (25-
100)
7.6
7.7
7.8
7.9
7.9
8.0
8.2
VVS
(101-
500)
10.1
10.3
10.5
10.6
10.7
10.9
11.6
VS
15.6
16.2
16.8
17.1
17.5
18.1
19.1
S
43.7
45.5
47.3
48.7
50.3
53.3
61.8
M
72.1
82.4
100.2
111.7
123.9
144.7
189.6
L
468.5
541.8
670.2
752.7
841.6
992.9
1333.1
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Federal Register/Vol. 64, No. 211/Tuesday, November 2, 1999 / Proposed Rules
TABLE XIII.15.—AVERAGE ANNUAL COST PER SYSTEM—Continued
[$Thousands, 1997]
Radon Level
(pCi/l)
Average costs to public systems exceeding radon levels
VVS (25-
100)
VVS
(101-
500)
VS
S
M
L
Average costs to private systems exceeding radon levels
VVS (25-
100)
VVS
(101-
500)
VS
S
M
L
Annual Per System Cost for those Systems Below Radon Levels: Monitoring Costs Only
All
0.3
0.3
0.4
0.6
1.1
2.6
0.3
0 3
0 4
06
1 1
26
4. Benefits From the Reduction of Co-
Occurring Contaminants
The occurrence patterns of industrial
pollutants are difficult to clearly define
at the national level relative to a
naturally occurring contaminant such as
radon. Similarly, the Agency's re-
evaluation of radon occurrence has
revealed that the geographic patterns of
radon occurrence are not significantly
correlated with other naturally
occurring inorganic contaminants that
may pose health risks. Thus, it is not
likely that a clear relationship exists
between the need to install radon
treatment technologies and treatments
to remove other contaminants. On the
other hand, technologies used to reduce
radon levels in drinking water have the
potential to reduce concentrations of
other pollutants as well. Aeration
technologies will also remove volatile
organic contaminants from
contaminated ground water. Similarly,
granular activated carbon (GAC)
treatment for radon removal effectively
reduces the concentrations of organic
(both volatile and nonvolatile)
chemicals and some inorganic
contaminants. Aeration also tends to
oxidize dissolved arsenic (a known
carcinogen) to a less soluble form that
is more easily removed from water. The
frequency and extent that radon
treatment would also reduce risks from
other contaminants has not been
quantitatively evaluated.
5. Impacts on Sensitive Subpopulations
The SDWA, as amended, includes
specific provisions in Section
1412(b)(3)(C)(i)(V) to assess the effects
of the contaminant on the general
population and on groups within the
general population such as children,
pregnant women, the elderly,
individuals with a history of serious
illness, or other subpopulations that are
identified as likely to be at greater risk
of adverse health effects due to exposure
to contaminants in drinking water than
the general population. The NAS Report
concluded that there is insufficient
scientific information to permit separate
cancer risk estimates for potential
subpopulations such as pregnant
women, the elderly, children, and
seriously ill persons. The NAS Report
did note, however, that according to the
NAS model for the cancer risk from
ingested radon, which accounts for 11
percent of the total fatal cancer risk from
radon in drinking water, approximately
30 percent of the fatal lifetime cancer
risk is attributed to exposure between
ages 0 to 10.
The NAS Report identified smokers as
the only group that is more susceptible
to inhalation exposure to radon progeny
(NAS 1999b). Inhalation of cigarette
smoke and radon progeny result in a
greater increased risk than if the two
exposures act independently to induce
lung cancer. NAS estimates that "ever
smokers" (more than 100 cigarettes over
a lifetime) may be more than five times
as sensitive to radon progeny as "never
smokers" (less than 100 cigarettes over
a lifetime). Using current smoking
prevalence data, EPA's preliminary
estimate for the purposes of the HRRC A
is that approximately 85 percent of the
cases of radon-induced cancer will
occur among current and former
smokers. This population of current and
former smokers, which consists of 58
percent of the male and 42 percent of
the female population, will also
experience the bulk of the risk reduction
from radon exposure reduction in
drinking water supplies.
6. Risk Increases From Other
Contaminants Associated With Radon
Exposure Reduction
As discussed in Section 7.2 of the
RIA, the need to install radon treatment
technologies may require some systems
that currently do not disinfect to do so.
Case studies (US EPA 1998j) of twenty-
nine small to medium water systems
that installed treatment (24 aeration, 5
GAC) to remove radon from drinking
water revealed only two systems that
reported adding disinfection (both
aeration) with radon treatment (the
other systems either had disinfection
already in place or did not add it). In
practice, the tendency to add other
disinfection with radon treatment may
be much more significant than these
case studies indicate. EPA also realizes
that the addition of chlorination for
disinfection may result in risk-risk
tradeoffs, since, for example, the
disinfection technology reduces
potential for infectious disease risk, but
at the same time can result in increased
exposures to disinfection by-products
(DBPs). This risk-risk trade-off is
addressed by the recently promulgated
Disinfectants and Disinfection By-
Products NPDWR (63 FR 69390). This
rule identified MCLs for the major
DBPs, with which all CWSs and
NTNCWSs must comply. These MCLs
set a risk ceiling from DBPs that water
systems adding disinfection in
conjunction with treatment for radon
removal could face. The formation of
DBPs correlates with the concentration
of organic precursor contaminants,
which tend to be much lower in ground
water than in surface water. In support
of this statement, the American Water
Works Association's WATERSTATS
survey (AWWA 1997) reports that more
than 50% of the ground water systems
surveyed have average total organic
carbon (TOC) raw water levels less than
1 mg/L and more than 80% had TOC
levels less than 3 mg/L. On the other
hand, WATERSTATS reports that less
than 6% of surface water systems
surveyed had raw water TOC levels less
than 1 mg/L and more than 50% had
raw water TOC levels greater than 3 mg/
L. In fact, this survey reports that more
than 85% of surface water systems had
finished water TOC levels greater than
1 mg/L.
The NAS Report addressed several
important potential risk-risk tradeoffs
associated with reducing radon levels in
drinking water, including the trade-off
between risk reduction from radon
treatment that includes post-
disinfection with the increased potential
for DBP formation (NAS 1999b). The
report concluded that, based upon
median and average total
trihalomethane (THM) levels taken from
a 1981 survey, ground water systems
would face an incremental individual ,
lifetime cancer risk due to chlorination
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Federal Register/Vol. 64, No. 211/Tuesday, November 2, 1999/Proposed Rules
59331
byproducts of 5 x 10~5. It should be
emphasized that this risk is based on
average and median Trihalomethane
(THM) occurrence information that does
not segregate systems that disinfect from
those that do. It should also be noted
that this survey pre-dates the
promulgation of the Stage I Disinfection
Byproducts Rule by almost twenty
years. Further, the NAS Report points
out that this average DBF risk is smaller
than the average individual lifetime
fatal cancer risk associated with
baseline radon exposures from ground
water (untreated for radon), which is
estimated at 1.2 x 10~4 using a mean
radon concentration of 213 pCi/L.
While this risk comparison is
instructive, a more meaningful
relationship for the proposed radon rule
would be to compare the trade-off
between radon risk reduction from
radon treatment and introduced DBF
risk from disinfection added along with
radon treatment. EPA emphasizes that
this risk trade-off is only of concern to
the small minority (<1%) of small
ground water systems with radon levels
above the AMCL of 4000 pCi/L and to
the small minority of large ground water
systems that are not already
disinfecting. Presently, approximately
half of all small community ground
water systems already have disinfection
in place, as shown in Table XIII.5. The
proportion of systems having
disinfection in place increases as the
system's size increases; >95% of large
ground water systems currently
disinfect. In terms of the populations
served, 83% of persons served by small
community ground water systems (those
serving 10,000 persons or fewer) already
receive disinfected drinking water and
95% of persons served by large ground
water systems already receive
disinfected drinking water. As shown in
Tables XIII. 16 and XIII. 17, even for
those ground water systems adding both
radon treatment and disinfection, this
risk-risk trade-off tends to be very
favorable, since the risk reduction from
radon removal greatly outweighs the
added risk from DBP formation.
An estimate of the risk reduction due
to treatment of radon in water for
various removal percentages and
finished water concentrations is
provided in Table XIII. 16. These risk
reductions are much greater than NAS's
estimate of the average lifetime risk
from DBP exposure for ground water
systems, by factors ranging from 3.5 for
low radon removal efficiencies (50%) to
more than 130 for higher radon removal
efficiencies (>95%).
TABLE XIII.16.—RADON RISK REDUC-
TIONS RESULTING FROM WATER
TREATMENT
Radon Influ-
ent (Raw
Water) level,
pCi/L
500
750
1000
2500
4000 . . .
10000
Required
removel effi-
ciency
(percent)
52
68
76
90
94
98
Reduced lifetime
risk resulting
from Water
Treatment for
. Radon in Drink-
ing Water 1
1.7 x 10 ~4
3.4 x 10 ~4
5.1 x 10 ~4
1 5 x 1C-3
2.5 x 10 ~3
6.5x10-3
1 Assumes that water is treated to 80% of
the radon MCL.
Table Xm.17 demonstrates the risk-risk trade-off between the risk reduction from radon removal and the risks intro-
duced from total trihalomethanes (TTHM) for two scenarios: (1) the resulting TTHM level is 0.008 mg/L (10% of the
TTHM MCL) and (2) the resulting TTHM level is 0.080 mg/L (the TTHM MCL). The table demonstrates that the risk-
risk trade-off is favorable for treatment with disinfection, even for situations where radon removal efficiencies are low
(50%) and TTHM levels are present at the MCL. While accounting quantitatively for the increased risk from DBP
exposure for systems adding chlorination in conjunction with treatment for radon may somewhat decrease the monetized
benefits estimates, disinfection may also produce additional benefits from the reduced risks of microbial contamination.
TABLE XIII.17.—RADON RISK REDUCTION FROM TREATMENT COMPARED TO DBP RISKS
Radon influent (Raw Water) level pCi/L
500
7SO
1000
2500
4000
10000
(NAS) 2
4
7
10
30
50
130
TTHMs
present at
10% of
TTHM MCL
(0.080 mg/
L)3
30
60
90
300
500
1200
TTHMs
present at
MCL
3
6
9
30
50
120
Estimated risk ratios: (lifetime risk reduc-
tion from radon removal1 / lifetime aver-
age risk from TTHMs in chlorinated
groundwater)
Notes: 1 From Table XIII.16.
8 From Appendix D in: National Research Council, Risk Assessment of Radon in Drinking Water, National Academy Press, Washington, DC.
1999. DBP concentrations are from a 1981 study and therefore pre-date the Stage 1 DBP NPDWR.
3 US EPA Regulatory Impact Analysis for the Stage 1 Disinfectants/Disinfection Byproducts Rule. Prepared by The Cadmus Group. November
12, 1998. Analysis is based on the 95% upper confidence interval value from the Integrated Risk Information System (IRIS) lifetime unit risks for
each THM. TTHM Is assumed to comprised by 70% chloroform, 21% bromodichloromethane, 8% dibromochloromethane, and 1% bromofqrm.
4 US EPA. Regulatory Impact Analysis for the Stage 1 Disinfectants/Disinfection Byproducts Rule. Based on the 95% upper confidence interval
value from the Integrated Risk Information System (IRIS) for the lifetime unit risk for dibromochloromethane (2.4 x 10 -6 risk of cancer case over
70 years of exposure).
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7. Other Factors: Uncertainty in Risk,
Benefit, and Cost Estimates
Estimates of health benefits from
radon reduction are uncertain. EPA is
including an uncertainty analysis of
radon in drinking water risks in Section
XII of the preamble to the proposed
radon rule. A brief discussion on the
uncertainty analysis is also shown in
Section 10 of the RIA (USEPA 1999f) for
radon in drinking water. Monetary
benefit estimates are also affected by the
VSL estimate that is used for fatal
cancers. The WTP valuation for non-
fatal cancers has less impact on benefit
estimates because it contributes less
than 1 percent to the total benefits
estimates, due to the fact that there are
few non-fatal cancers relative to fatal
cancers and they receive a much lower
monetary valuation.
8. Costs and Benefits of Multimedia
Mitigation Program Implementation
Scenarios
In addition to evaluating the costs and
benefits across a range of radon levels,
EPA has evaluated five scenarios that
reduce radon exposure through the use
of MMM programs. The implementation
assumptions for each scenario are
described in the next section. These five
scenarios are described in detail in
Section 9 of the RIA. For the MMM
implementation analysis, systems were
assumed to mitigate water to the 4,000
pCi/L Alternative Maximum
Contaminant Level (AMCL), if
necessary, and that equivalent risk
reduction between the AMCL and the
radon level under evaluation would be
achieved through a MMM program.
Therefore, the actual number of cancer
cases avoided is the same for the MMM
implementation scenarios as for the
water mitigation only scenario. A
complete discussion on why MMM is
expected to achieve equal or greater risk
reduction is shown in Section VLB of
the preamble for the proposed radon
rule.
For the RIA, EPA used a simplified
approach to estimating costs of
mitigating indoor air radon risks. A
point estimate of the average cost per
life saved under the current voluntary
radon mitigation programs served as the
basis for estimating the costs of risk
reduction under the MMM options. The
Agency has estimated the average
screening and mitigation cost per fatal
lung cancer avoided to be
approximately $700,000, assuming the
current distribution of radon in indoor
air, that all homes would be tested for
radon in indoor air, and that all homes
at or above EPA's voluntary action level
of 4 pCi/L would be mitigated. This
value was originally derived based on
data gathered in 1991. The same value
has been used in the RIA, without
adjustment for inflation, after
discussions with personnel from EPA's
Office of Radiation and Indoor Air
indicated that screening and mitigation
costs have not increased since 1991.
9. Implementation Scenarios
EPA evaluated the annual cost of five
MMM implementation scenarios that
span the range of participation in MMM
programs that might occur when a radon
NPDWR is implemented. Each scenario
assumes a different proportion of States
will comply with the AMCL and
implement MMM programs. It has been
assumed that "50 percent of States"
implies 50 percent of systems in the
U.S; "60 percent of States" implies 60
percent of systems, and so on.
Scenario A: 50 percent of States
implement MMM programs.
Scenario B: 60 percent of States
implement MMM programs.
Scenario C: 70 percent of States
implement MMM programs.
Scenario D: 80 percent of States
implement MMM programs.
Scenario E: 95 percent of States
implement MMM programs.
States that do not implement MMM
programs instead must review and
approve any system-level MMM
programs prepared by community water
systems. In these States, regardless of
scenario, 90 percent of systems are
assumed to comply with the AMCL and
to implement a system-level MMM
program and 10 percent are assumed to
comply with the MCL. EPA requests
comment on whether this is an
appropriate assumption.
10. Costs and Benefits of MMM
Implementation Scenarios
Table XIII. 18 shows the total annual
system-level and State-level costs for
each MMM scenario, assuming an MCL
of 300 pCi/L and AMCL of 4,000 pCi/
L. Additional MMM scenario cost and
benefit tables for MCL levels of 100,
500, 700, 1000, 2000, and 4000 pCi/L
are shown in Appendix E of the RIA.
System, State, and MMM mitigation
costs decrease from $121.1 million to
$60.4 million as the percentage of States
implementing MMM programs increases
from 50 to 95 percent. System-level
costs decrease from $104 million to $47
million as the percentage of States
implementing MMM programs increases
from 50 to 95 percent. Costs for actual
mitigation of radon in indoor air rise
from $3.9 million to $4.1 million as the
percentage of States implementing
MMM programs rises from 50 to 95
percent. Note that these mitigation costs
are relatively flat because all scenarios
assume that 95 percent or more of the
risk reduction will be achieved through
MMM at either the State or local level.
Table XIII. 19 represents the ratios of
benefits to costs of MMM programs for
each scenario, by system size. Only the
ratios in the bottom row of the table
include costs to the States. The balance
of the numbers presented here represent
local benefits and costs only and as
such, somewhat overstate the net
benefits of the scenarios. Benefit-cost
ratios are generally less than one for the
smallest system size category (systems
serving less than 500 people), but
greater than one for larger systems
under all five scenarios. For larger
systems, benefit-cost ratios range from
2.6 for systems serving 501-3,300
people under Scenario A to
approximately 41.4 for systems serving
10,001 to 100,000 people under
Scenario E. Overall benefit-cost ratios
are over one for all five scenarios. This
pattern is seen primarily because a
larger proportion of smaller systems
have influent radon levels exceeding
4000 pCi/L. A larger proportion of small
systems versus large systems therefore,
incur water mitigation costs to comply
with the AMCL.
Table XIII.20 shows the net benefits
(benefits minus costs) of the various
MMM implementation scenarios. As
would be expected from the benefit-cost
ratios shown in Table XIII. 19, all
systems serving more than 500 people
realize net positive benefits under all
five scenarios. By far the largest
proportion of net benefits is realized by
systems serving 10,001 to 100,000
people.
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Federal Register/Vol. 64, No. 211 /Tuesday, November 2, 1999/Proposed Rules
59333
TABLE XIII.18 (A).—ANNUAL SYSTEM—LEVEL AND STATE—LEVEL COSTS ASSOCIATED WITH THE MULTIMEDIA MITIGATION
AND AMCL OPTION
[$ Millions/Year] [MCL=300 pCi/L]
System size
Scenario A
45% imple-
ment system-
level MMM
program; 5%
mitigate water
to 300 piC/L
MCL; 95%
mitigate water
to 4000 piC/L
AMCL
Scenario B
36% imple-
ment system-
level MMM
program; 4%
mitigate water
to 300 piC/L
MCL; 96%
mitigate water
to 4000 piC/L
AMCL
Scenario C
27% imple-
ment system-
level MMM
program; 3%
mitigate water
to 300 piC/L
MCL; 97%
mitigate water
to 4000 piC/L
AMCL
Scenario D
18% imple-
ment system-
level MMM
program; 2%
mitigate water
to 300 piC/L
MCL; 98%
mitigate water
to 4000 piC/L
AMCL
Scenario E
5% implement
system-level
MMM pro-
gram; 5% miti-
gate water to
300 piC/L
MCL; 99.5%
mitigate water
to 4000 piC/L
AMCL
System Costs for Water Mitigation ($ millions/year)
25-100
101-500
501-3300
3301-10000
10 001-100 000
>100,000
Total CWS Water Mitigation Costs
10.2
17.6
9.9
5.5
7.5
2.0
52.7
9.7
16.9
9.2
5.0
6.6
> 1.7
49.1
9.3
16.3
8.5
4.5
5.6
1.4
45.4
8.8
15.6
7.7
3.9
4.6
1.1
41.8
8.1
14.6
6.7
3.1
3.2
0.7
36.3
Water System Administration Costs ($ millions/year)
25-100
101-500
501-3300
3301-10000
10001-100,000
>100 000
Total CWS Administrative Costs
Total CWS Water Mitigation and Administrative
Costs
17.0
17.4
12.0
3.0
1.7
0.1
51.2
104.0
14.0
14.3
9.9
2.5
1.4
0.1
42.1
91.2
11.0
11.3
7.8
1.9
1.1
0.1
33.1
78.5
8.0
8.2
5.7
1.4
0.8
0.0
24.1
65.9
3.7
3.8
2.6
0.6
0.4
0.0
11.1
47.4
TABLE Xlll.18 (B).-
-STATE MMM ADMINISTRATIVE COSTS
[$ millions/year]
Scenario A
50% of states
implement
state-wide
MMM pro-
grams; 45% of
CWS imple-
ment system-
level MMM
program
Scenario B
60% of states
implement
state-wide
MMM pro-
gram; 35% of
CWS imple-
ment system-
level MMM
program
Scenario C
70% of states
implement
state-wide
MMM pro-
gram; 25% of
CWS imple-
ment system-
level MMM
program
Scenario D
80% of states
implement
state-wide
MMM pro-
gram; 15% of
CWS imple-
ment system-
level MMM
program
Scenario E
95% of states
implement
state-wide
MMM pro-
gram; 5% of
CWS imple-
ment system-
level MMM
program
State costs associated with State-wide MMM program administration, reviewing system-level MMM programs, and reviewing system-
level water mitigation requirements are not distributable across different system sizes.
State Administration Costs for Water Mitigation
State Administration Costs for State-Level MMM Mitigation
State Administration Costs for System-Level MMM Mitiga-
tion
Total State Administration Costs
2.5
2.9
7.8
13.2
2.5
3.5
6.1
12.1
2.5
4.1
4.4
10.9
2.5
4.7
2.6
9.8
2.5
5.6
0.9
8.9
TABLE Xlll.18 (C).—MMM TESTING AND MITIGATION COSTS
[$ million/year]
CWS MMM Costs
State MMM Costs
Total MMM Costs
Scenario A
1.9
2.1
3.91
Scenario B
1.5
2.5
3.95
Scenario C
1.1
2.9
3.99
Scenario D
0.7
3.3
4.03
Scenario E
0.2
3.9
4.12
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TABLE XIII.18 (C).—MMM TESTING AND MITIGATION COSTS—Continued
[$ million/year]
Total Costs (From Tables XIII. 18 A, B, and C)
Scenario A
121.1
Scenario B
107.3
Scenario C
93.4
Scenario D
79.7
Scenario E
60.4
TABLE XIII.19.—RATIO OF BENEFITS AND COSTS BY SYSTEM SIZE FOR EACH SCENARIO (MCL=300 pQ/L)
System size
25-100
101-500
501-3 300
3 301—10 000
10 001-100,000
>100,000
OVERALL
Benefits, $M
3.5
16.9
58.0
59.2
147.3
76.7
361.6
Scenario A
0.13
0.48
2.59
6.87
15.82
37.16
2.98
Scenario B
0.14
0.53
2.98
7.85
18.35
43.70
3.37
Scenario C
0.17
0.61
3.51
9.16
21.84
53.04
3.87
Scenario D
0.21
0.70
4.27
11.0
26.96
67.44
4.54
Scenario E
0.30
0.92
6.23
15.61
41.43
113.68
5.99
TABLE XIII.20.—NET BENEFITS BY SYSTEM SIZE FOR EACH SCENARIO1
System size
25-100
101-500
501-3,300
3 301-10 000
10 001-100 000
>100,000
OVERALL
Benefits, $M
3.5
16.9
58.0
59.2
147.3
76.7
361.6
Scenario A
(24.3)
(18.7)
35.6
50.6,
138.0
74.6
240.5
Scenario B
(20.7)
(14.8)
38.6
51.7
139.3
74.9
254.3
Scenario C
(17.1)
(11.0)
41.5
52.7
140.6
75.3
268.2
Scenario D
(13.5)
(7.1)
44.4
53.8
141.8
75.6
281.9
Scenario E
(8.3)
(1.6)
48.7
55.4
143.7
76.0
301.2
1 Parentheses indicate negative numbers.
H. Response to Significant Public
Comments on the February 1999
HRRCA
To provide the public with
opportunities to comment on the Health
Risk Reduction and Cost Analysis
(HRRCA) for radon in drinking water,
the Agency published the HRRCA in the
Federal Register on February 26, 1999
(64 FR 9559). The HRRCA was
published six months in advance of this
proposal and illustrated preliminary
cost and benefit estimates for various
MCL options under consideration for
the proposed rule. The comment period
on the HRRCA ended on April 12, 1999,
and EPA received approximately 26
written comments from a variety of
stakeholders, including the American
Water Works Association, the National
Rural Water Association, the National
Association of Water Companies, the
Association of Metropolitan Water
Agencies, State departments of
environmental protection, State health •
departments, State water utilities and
local water utilities.
Significant comments on the HRRCA
addressed the topics of radon
occurrence, exposure pathways,
sensitive sub-populations and the risks
to smokers, risks from existing radon
exposures, risks associated with co-
occurring contaminants, risk increases
associated with radon removal, the
benefits of reduced radon exposures, the
costs of radon treatment measures, the
cost and benefit results, and the
Multimedia Mitigation (MMM) program.
The following discussion outlines the
significant comments received on the
HRRCA and the Agency's response to
these comments.
1. Radon Occurrence
Several commenters had concerns
related to EPA's analysis of radon
occurrence. Two commenters felt that
the radon levels in Table 3.1 of the
HRRCA were too low and not
representative of radon occurrence in
their regions. A California water utility
indicated that due to limitations of the
NIRS, EPA should conduct a new
national radon survey, with special
emphasis on determining radon levels
in the largest systems, before
promulgating the rule. Two commenters
from Massachusetts expressed concerns
about radon occurrence. One suggested
that additional analysis of radon
variability in individual wells was
required, and another indicated that the
effects of storage and residence time on
radon levels in supply systems needed
to be taken into account. One
commenter indicated that EPA should
more strongly consider that most risk
reductions predicted in the HRRCA
come from reductions in radon levels in
the small proportions of systems with
initial very high radon levels.
EPA Response 1-1
As part of the regulatory development
process, EPA updated and refined its
analysis of radon occurrence patterns in
ground water supplies in the United
States. This new analysis incorporated
information from the EPA 1995 National
Inorganic and Radionuclides Survey
(NIRS) of 1000 community ground water
systems throughout the United States,
along with supplemental data provided
by States, water utilities, and academic
researchers. EPA's current re-evaluation
used data from 17 States to determine
the differences between radon levels in
ground water and radon levels in
distribution systems in the same
regions. The results of these
comparisons were used to estimate
national distributions of radon
occurrence in ground water. EPA
believes that the existing NIRS data,
along with the Agency's updates to this
data, currently provide the most
comprehensive national-level analysis
of radon occurrence patterns in ground
water supplies. This analysis is not
intended for the estimation of radon
occurrence at the state-level.
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59335
Variability within the NIRS radon
occurrence data was analyzed for
several important contributing factors:
within-well (temporal) variability,
sampling and analytical (methods)
variability, intra-system variability
(variability between wells within a
single system), and inter-system
variability (variability between wells in
different systems). Several important
conclusions were drawn from this
analysis. First and foremost is the
conclusion that the NIRS data do
capture the major sources of radon
occurrence variability and thus can be
used directly, without any additional
correction for temporal or sampling and
analytical variability, to provide
reasonable national estimates of radon
levels and variability levels in ground
water drinking supplies. In addition,
EPA analyzed the additional data sets
provided from stakeholders (described
previously) in conjunction with the
NIRS radon data to estimate the
magnitudes of the variability sources.
Based on all of these analyses, EPA has
concluded that the variability between
systems dominates the over-all
variability (it comprises approximately
70 percent of the over-all variability).
Temporal variability (13-18 percent),
sampling and analytical variability (less
than 1 percent), and intra-system
variability (12-17 percent) are relatively
minor by comparison. These results are
discussed in detail elsewhere (USEPA
1999b).
Note: These estimates of variability sources
apply to national-level radon occurrence
estimates: individual regions may have
systems that show variability sources that
deviate significantly from these values.
This analysis of variability was
incorporated into EPA's estimates of
nation-wide radon occurrence and was
used in its estimates of the effects of
uncertainty in occurrence information
on total national costs of compliance.
In response to the comment that
"most risk reductions predicted in the
HRRCA come from reductions in radon
levels in the small proportions of
systems with initial very high radon
levels", EPA agrees that a system with
high radon levels would benefit more
from water mitigation than a system
with much lower initial radon levels,
but the vast majority of the national
water mitigation benefits come from
systems that are above the MCL, but not
that high above it (e.g.. 80 percent
removal required for the system to be at
the MCL). This is true since radon is
approximately log-normally distributed
(I.e., a much higher percentage of water
systems can be expected to have
relatively low radon levels than
relatively high radon levels) and hence
most systems fall into this category. For
this reason, the summation of these
smaller per system benefits enjoyed by
the large number of systems nearer the
MCL greatly outweigh summation of the
larger per system benefits enjoyed by
the minority of systems with very high
radon levels. This is demonstrated in
Table 6-2 of the HRRCA ("Estimated
Monetized Benefits from Reducing
Radon in Drinking Water"), in which
the central tendency estimate of
monetized benefits associated with an
MCL of 500 pCi/L is 212 million dollars
and the benefits associated with an MCL
of 100 pCi/L is 673 million dollars. This
means that, in the latter case, 461
million dollars of the benefits come just
from the systems with radon levels
between 100 and 500 pCi/L (80 percent
removal required), while the remaining
benefits (212 million dollars) come from
the systems with radon levels from 500
pCi/L up to the highest radon levels.
Five commenters indicated that the
estimates of the numbers of entry points
per system used in the HRRCA were
incorrect, in that large systems had far
more entry points than the numbers
given in Table 5.4 of the HRRCA.
Several of these commenters cited data
from the Community Water System
Survey (CWSS), showing higher
numbers of wells per system in each
system size category than were used for
cost calculations in the HRRCA.
EPA Response 1-2
The relevant distribution for costing
out non-centralized treatment is the
number of entry points, not the number
of wells. A given entry point (the point
at which treatment is applied) may be
fed by several wells, and hence there is
a discrepancy in numbers between the
HRRCA, which reported a distribution
of entry points, and Table 1-5 of the
Community Water System Survey
(CWSS), which reported the average
number of wells per system. These
numbers are related, but not directly
comparable. In general, the average
number of entry points for a class of
ground water systems would be
expected to be smaller than the average
number of wells. In the HRRCA, the
distribution of entry points per system
was estimated from a statistical analysis
("bootstrap analysis") of the well and
entry point data from the CWSS. This
statistically-calculated distribution was
then used to estimate the percentage of
systems within a system size category
having a given number of entry points.
However, as part of its uncertainty
analysis, EPA has used the 95%
confidence upper bound of the site
distribution in the national cost
estimates supporting this proposal. The
average number of entry points per
system is roughly 10% higher using this
upper bound analysis. In addition, to
test the effects of varying this
distribution on the national costs of
compliance, the per system costs, and
the per household costs, EPA conducted
an uncertainty analysis (Monte Carlo
analysis including sensitivity) on the
distribution by simultaneously varying
both the percentages of systems
estimated to have a particular number of
sites and the estimated number of sites.
The results of this analysis are reported
both in this notice and in the Regulatory
Impact Analysis. It should be noted that
the treatment unit costs and total
number of systems dominated the cost
uncertainty and that the entry point
distribution was a relatively minor
contributor to the overall cost
uncertainty.
2. Exposure Pathways
A number of issues related to radon
exposure pathways were raised. Several
commenters indicated that the risks
associated with the build-up of radon in
carbon filters needed to be addressed in
HRRCA. Concerns were also expressed
about general population exposures to
radon in air released from aeration
facilities and exposures to workers at
water utilities. Another commenter said
that EPA should discuss the persistence
of radon in the body after ingestion.
EPA Response 2-1
The risks from radon build-up in
carbon filters and radon off-gas
emissions are discussed in some detail
in this notice, including an evaluation
of risks, a discussion of references, and
responses from a survey of air
permitting boards about the permitting
of radon off-gas.
EPA Response 2-2
The persistence of radon in the body
following ingestion has been
investigated and the results have been
presented in the Criteria Document for
Radon (USEPA 1999b). In brief, radon
ingested in water is well-absorbed from
the stomach and small intestine into the
bloodstream and transported throughout
the body. Radon is rapidly (within
approximately one hour) excreted from
the body via the lungs, so only about 1
percent of ingested radon undergoes
radioactive decay while in the body.
The risks from the retained radon and
its decay products in various organs are
calculated by NAS and adopted by EPA
in the proposed rule.
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3. Nature of Health Impacts
No comments were made concerning
the general nature of adverse effects
associated with radon exposure.
Comments concerning specific aspects
of health impact evaluation are
summarized in the following sections.
. (a) Sensitive subpopulations, risks to
smokers, non-smokers. Comments on
these sections are addressed together
because the majority of the comments
had to do with the characterization of
smokers as a sensitive population.
Several commenters noted that most
risk reduction from reducing radon
exposure occurs among smokers, and
took the position that EPA should not
include risk reductions to smokers in its
benefits assessment, because smoking
can be viewed as a voluntary risk. One
commenter suggested that the smokers'
willingness to pay for cigarettes also
indicated a willingness to face the risk
of smoking.
EPA Response 3-1
The term, "groups within the general
population" is addressed, but not
comprehensively defined, in the 1996
amendments to the Safe Drinking Water
Act (SDWA, §'1412(b)(3)(C)). The
definition of sensitive subpopulations is
an issue for discussion and debate, and
EPA is interested in input from
stakeholders. The National Academy of
Sciences (NAS) Radon in Drinking
Water Committee, as part of their
assessment of the risks of radon in
drinking water, has considered whether
groups within the general population,
including smokers, may be at increased
risk. The NAS Committee has indicated,
in their Risk Assessment of Radon in
Drinking Water report, that smokers are
the only group within the general
population that is more susceptible to
inhalation exposure to radon progeny,
but did not specifically identify smokers
as a sensitive subpopulation.
In this proposal, EPA is basing its risk
management decision on risks to the
general population. The general
population includes smokers as well as
former smokers. The risk assessments
for radon in air and water are based on
an average member of the population,
which includes smokers, former
smokers, and non-smokers. A more
complete discussion on the risks of
radon in drinking water and air is
presented in the NAS's risk assessment
report and in Section XII of this
preamble.
(b) Risk reduction model, risks from
existing radon exposures. Commenters
raised only one concern associated with
the risk model used to estimate radon
reduction benefits. Three commenters
suggested that EPA should consider
adopting a threshold-based model for
radon carclnogenesis, and that EPA's
current (non-threshold) approach
overestimates radon risks. In support,
the commenters cited a recently
published paper (Miller et al, 1999) as
providing evidence that a single alpha
particle "hit" typical in low-level radon
may not be sufficient to cause cell
transformation leading to cancer.
EPA Response 3-2
There are a number of papers that
have recently examined the effects of a
single alpha particle on a cell nucleus
of mammalian cells in culture. The
authors of this study concluded that
cells were more likely to be transformed
to cancer causing cells if there were
multiple alpha particle hits to their
nuclei. However, another study, Hei et
al. (1997), using a similar methodology,
found direct evidence that a single
"particle traversing a cell nucleus will
have a high probability of resulting in a
mutation" and concluded that their
work highlighted the need for radiation
protection at low doses. Moreover,
follow-up microbeam experiments
described by Miller et al. at the 1999
International Congress of Radiation
Research demonstrated that one alpha
particle track through the nucleus was
indeed sufficient to induce
transformation under some
experimental conditions.
Epidemiological data relating to low
radon exposures in mines also indicate
that a single alpha track through the cell
may lead to cancer. Finally, while not
definitive by themselves, the results
from residential case-control studies
provide some direct support for the
conclusion that environmental levels of
radon pose a risk of lung cancer. EPA
has based its current risk estimates for
radon in drinking water on the findings
of the National Academy of Sciences.
Rather than focus on the results of any
one study, the NAS committees based
their conclusions on the. totality of data
on radon—-a weight-of-evidence
approach.
Both the BEIR VI Report (NAS 1999a)
and their report on radon in drinking
water (NAS 1998b) represent the most
definitive accumulation of scientific
data gathered on radon since the 1988
NAS BEIR IV (NAS 1988). These
committees' support for the use of
linear-non-threshold relationship for
radon exposure and lung cancer risk
came primarily from their review of the
mechanistic information on alpha-
particle-induced carcinogenesis,
including studies of the effect of single
versus multiple hits to cell nuclei.
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-nonthreshold 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
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.
(c)Risk and risk reduction associated
with co-occurring contaminants. Several
commenters addressed the issue of risks
associated with co-occurring
contaminants. Other commenters
indicated a need to include risks and
risk reductions from co-occurring
contaminants.
EPA Response 3-3
The contaminants that may co-occur
with radon that are of main concern are
those that can cause fouling of aeration
units (or otherwise impede treatment)
and those that are otherwise affected by
the aeration process in such a way as to
increase risks. Measures and costs to
avoid aeration fouling are discussed in
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59337
this notice and in the references cited.
Arsenic co-occurrence may be relevant
since some systems may have to treat for
both, but the treatment processes are not
incompatible. In fact, the only side-
effect of the aeration process that may
impact the removal of arsenic would be
the potential oxidation of some fraction
of less easily removed As(IV) form to the
more easily removed As(VI) form. There
would be no additional costs due to this
effect, and in fact, there may be cost
savings involved. The potential for
increased risks due to potential
disinfectant by-product formation after
disinfection, is discussed next.
(d) Risk increases associated with
radon removal. Five commenters said
that EPA should include quantitative
estimates of the risk increases associated
with increased exposure to disinfection
byproducts (DBFs) in the risk and cost-
benefit analyses of the HRRCA. One
commenter said that risks should be
apportioned appropriately between the
proposed radon rule and the
Groundwater rule. Another commenter
maintained that, contrary to the
assertion in the HRRCA, there would be
no reduction in microbial risks due to
the increased disinfection associated
with the radon rule because most
groundwater sources currently present
no microbial risks.
EPA Response 3-4
EPA would like to highlight that the
AMCL/MMM option is the preferred
option for all drinking water systems,
which would result in very few water
treatment systems adding disinfection.
EPA expects the radon rule to result in
a minority of ground water systems
choosing the MCL option, and of those,
many will be larger systems. Since very
few small systems are expected to
choose the MCL option , very few
systems are above the AMCL of 4000
pCi/L, and most large ground water
systems already disinfect their water,
few systems are expected to add
disinfection in response to the radon
rule, i.e., increased risk due to
disinfection by-product formation
should not be a significant issue.
However, EPA does evaluate this risk-
risk trade-off in this notice for that
minority of systems that will be
expected to add disinfection with
treatment for radon. For that minority of
systems, the trade-off between
decreased risks from radon and
increased risks from disinfection-by-
products is favorable.
4. Benefits of Reduced Radon Exposure
The majority of the comments related
to the estimation of benefits focused on
the methods used to monetize
reductions in cancer risks. There were
also a few comments on non-
quantifiable benefits, and on several
other topics. The previous comments
pertaining to risk reductions to smokers
and that benefits from these risk
reductions should be excluded from the
HRRCA apply here as well.
(a) Nature of regulatory benefits.
There were few comments on this
section, most of which pertained to non-
quantifiable benefits. One commenter
indicated that the peace-of-mind non-
quantifiable benefit from radon
reduction would be offset by the anxiety
of those living near aeration plants.
Another noted that peace-of-mind
benefits were not easy to quantify for
non-threshold pollutants like radon and,
in fact, that the regulation of radon
might actually increase anxiety by
drawing attention to the risks associated
with radon exposures. Commenters also
noted that claiming arsenic reduction as
a benefit from aeration is questionable
because there is no demonstrated
correlation between the levels of radon
and arsenic in groundwater systems.
EPA Response 4-1
By definition, non-quantifiable
benefits cannot be measured and have
not been measured in the HRRCA
analysis. Thus, comparisons of types of
such benefits are not very meaningful.
EPA attempts to note these potential
benefits when the Agency believes they
might occur, as in the case of peace-of-
mind benefits from radon reduction.
There may also be non-quantifiable
costs that may offset any non-
quantifiable benefits. These include
anxiety on the part of residents near
treatment plants and customers who
may not have previously been aware of
radon in their water. As noted
elsewhere in this preamble, EPA
believes it unlikely that accounting for
these non-quantifiable benefits and
costs quantitatively would significantly
alter the overall assessment.
(b) Monetization of benefits.
Comments related to risk reduction have
been discussed in previous responses,
so are not discussed further here.
Commenters addressed all three
approaches to monetizing benefits: the
value of statistical life; the costs of
illness; and willingness-to-pay. A
number of commenters suggested the
use of Quality-Adjusted Life Years
(QALY) as an alternative approach to
the valuation of health benefits. One
commenter indicated that the use of
QALYs was a good way to avoid having
to monetize health outcomes. Two
commenters indicated that QALYs had
the advantage of being able to take into
account the delayed onset of cancer, as
well as reduced incidence. One
organization suggested QALYs as a
superior method for combining the
benefits from fatal and non-fatal illness
over different time periods; which
would be particularly useful in the case
of smokers, whose cancers are likely to
be delayed, but not necessarily
prevented, by reductions in radon
exposure.
EPA Response 4-2
The use of QALYs has been
extensively discussed within EPA and
also before the Environmental
Economics Advisory Committee of
EPA's Science Advisory Board. At this
time, current Agency policy is to use
Value of Statistical Life (VSL) estimates
for the monetization of risk reduction
benefits. EPA believes QALY
calculations to be experimental and not
well established for the types of
analyses performed by the Agency.
(c) Value of statistical life (VSL).
Several commenters questioned the use
of, or the value selected for, the value
of statistical life as a measure of
benefits. Other commenters indicated
that the large range of uncertainty
associated with the estimates of risk
reduction called the VSL (and the
willingness-to-pay) methods into
question, and indicated that EPA
needed to better justify the central-
tendency VSL value selected for use in
the HRRCA. They maintained that the
VSL approach would only be
appropriate if the VSL estimates were
derived from "similar scenarios" to
those being evaluated in the HRRCA.
Another commenter suggested that
using the VSL was inappropriate in that
the VSL dollars did not represent (as do
compliance costs) actual resource losses
to society that could be spent on other
programs (e.g. pollution reduction).
Thus, the comparison of compliance
costs to VSL costs is not valid. They
strongly recommend the use of
compliance cost per life saved as an
appropriate measure for judging radon
control options. One commenter
indicated that the use of the VSL
approach resulted in greatly over-
estimated benefits of radon exposure
reduction, particularly because the VSL
for smokers is the same as for non-
smokers and does not account for the
age at which mortality is avoided.
Another questioned the validity of the
mean VSL value used in the HRRCA,
and indicated that VSL estimates should
only come from the peer-reviewed
scientific literature or from Agency
documents that had been subject to
public comment.
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EPA Response 4-3
The VSL value, currently
recommended by Agency guidance, is
derived from a statistical distribution of
the values found in twenty-six VSL
studies, which were chosen as the best
such studies available from a larger
body of studies. This examination of
studies was undertaken by EPA's Office
of Air and Radiation in the course of its
Clean Air Act retrospective analysis.
EPA believes the VSL estimate ($5.8
million, 1997 dollars) to be the best
estimate at this time, and is
recommending that this value be used
by the various program offices within
the Agency. This estimate may,
however, be updated in the future as
additional information becomes
available to assist the Agency in refining
its VSL estimate. The VSL estimate is
consistent with current Agency
economic analysis guidance, which was
recently peer reviewed by EPA's
Science Advisory Board.
d. Costs of illness (COI). Two
commenters suggested that EPA should
further review the literature on the costs
of illness and develop better cost
measures for the illnesses addressed in
the HRRCA.
EPA Response 4-4
EPA believes that the COI data is the
most complete analysis of this type
currently underway. The cost of illness
(COI) data shown in the HRRCA were
presented as a comparison to
Willingness to Pay (WTP) to avoid
chronic bronchitis. The Agency did not
use the COI data to estimate risk
reduction valuations for non-fatal
cancers because these estimates can be
seen as underestimating the total WTP
to avoid non-fatal cancers. COI may
understate total WTP because of its
failure to account for many effects of
disease such as pain and suffering,
defensive expenditures, lost leisure
time, and any potential altruistic
benefits. It is important to note that the
proportion of benefits attributable to
non-fatal cancer cases accounts for less
than one percent of the total benefits in
the HRRCA.
(e) Willingness-to-pay. Several
commenters questioned EPA's use of the
willingness-to-pay (WTP) approach for
monetizing non-fatal cancer risk
reductions. Another suggested that a
WTP value for victims of non-fatal
' cancers should have been used, instead
of the WTP estimates for chronic
bronchitis. It was also suggested that
WTP measures would vary within the
general population, and that use of a
constant value was inappropriate.
EPA Response 4-5
EPA believes that the WTP estimates
to avoid chronic bronchitis are the best
available surrogate for WTP estimates to
avoid non-fatal cancers. WTP estimates
were used in the HRRCA as opposed to
COI to value non-fatal cancer cases. EPA
believes that COI may understate total
WTP because of its failure to account for
many effects of disease such as pain and
suffering, defensive expenditures, lost
leisure time, and any potential altruistic
benefits. It is important to note that the
proportion of benefits attributable to
non-fatal cancer cases accounts for less
than one percent of the total benefits in
the HRRCA.
(f) Treatment of benefits over time.
Many commenters objected to EPA's
assumption that cancer risk reduction,
and hence benefits, would begin to
accrue immediately upon the reduction
of radon exposures. In addition, they
felt that the failure to discount health
benefits resulted in an overestimation of
the benefits. One commenter suggested
that a "gradual phase-in" of risk
reduction should be incorporated into
the HRRCA benefits calculation. It was
also suggested that an alternative to
immediate benefits accrual be used, and
that the effects of the immediate benefits
accrual assumption be discussed in
detail with regard to the uncertainties it
introduces into the benefits estimates.
One commenter identified the
assumption of immediate benefits as a
major source of benefits overestimation.
Another comment asked that EPA
provide better justification for assuming
immediate benefits accrual, and
suggests instead that a linear phase-in of
risk reduction over 70 years would be
more appropriate. Three commenters
also indicate that the failure to take
latency of risk reduction into account
and to discount benefits appropriately,
greatly biases the benefits estimates in
the upward direction. One commenter
indicated that the failure to discount
benefits resulted in a five- to ten-fold
over-estimation.
EPA Response 4-6
These comments address the issue of
latency, the difference between the time
of initial exposure to environmental
carcinogens and the onset of any
resulting cancer. Qualitative language
has been added to the preamble
regarding adjustments, including
latency, that could be made to benefits
calculations. This qualitative discussion
notes that latency is one of a number of
adjustments related to an evaluation of
potential benefits associated with this
rule. EPA believes that such
adjustments should be considered
simultaneously. For further discussion,
see section XIII.D of the preamble.
5. Costs of Radon Treatment Measures
(a) Drinking water treatment
technologies and costs. All of the
commenters had concerns related to
EPA's assumptions and analyses of costs
of radon treatment measures. In fact,
one commenter suggested that the entire
section was oversimplified by EPA.
Most of the commenters, however,
provided more specific comments
which are outlined next.
EPA Response 5-1
Most, if not all, commenters assumed
that EPA would propose that the risks
from radon would be best addressed by
drinking water systems attempting to
meet the MCL. Under this scenario,
many small systems would be in
situations where they faced very
difficult treatment issues, often with
technically difficult and/or expensive
solutions. However, EPA is suggesting
that the risks from radon are best
addressed by the combined use of the
AMCL with a multi-media mitigation
(MMM) program. Since the proposal
also includes a regulatory expectation of
adoption of the AMCL by small systems,
EPA believes that many of the
comments received are less applicable
to this proposal than if the MCL were
the preferred route of compliance.
(b) Aeration. Several commenters
expressed concerns related to aeration
costs. One major concern was EPA's
failure to address worker safety issues,
and the associated cost of occupational
safety programs, at treatment plants. A
reference to earlier studies of increased
risk to neighbors is provided, but details
are not included to evaluate these
studies. Concern was expressed that
costs for permitting and control of radon
emissions from treatment plants were
not included, and that the public might
react strongly to the presence of a local
treatment plant even if analysis showed
the risk to be minimal. Three
commenters noted that the HRRCA
failed to consider quantifiable corrosion
control costs associated with aeration.
Installation of aeration for radon
removal may also affect lead/copper
levels in the water distribution system,
resulting in additional treatment
modifications and costs. Many systems
will have to develop a different
corrosion control strategy to comply
with the lead and copper rule due to the
radon regulation.
EPA Response 5-2
Worker safety issues for aeration
treatment of radon in drinking water are
discussed in today's notice (Section
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59339
VIILA.3) and are discussed in more
detail in other sources (USEPA 1994b,
USEPA 1998H). Radon exposure to
workers in drinking water treatment
plants has been discussed in the
literature (e.g.. Fisher etal. 1996,
Reichelt 1996). In fact, these discussions
usually apply to situations where radon
is NOT the contaminant being
purposely removed, since there is
currently no regulatory driver to do so.
When ground water is exposed to air
during treatment for any contaminant,
radon may be released and may
accumulate in the treatment facility.
The National Research Council (NAS
1999b) suggests that the air in all
groundwater facilities treating for any
contaminant should be monitored for
radon and that ventilation should be
investigated as a means of reducing
worker exposure. In support of this
position, EPA would further strongly
suggest that systems that attempt to
meet the MCL (i.e., that are in States
that do not adopt the AMCL or
otherwise choose to meet the MCL) by
installing aeration treatment should take
the appropriate measures to monitor
and ventilate the treatment facilities.
For those small systems that choose
GAC treatment, other precautions
should be taken to monitor and control
gamma exposure. GAC treatment issues
are discussed later in this notice and are
discussed in detail elsewhere (USEPA
1994b, AWWARF 1998 and 1999).
EPA has suggested that occupational
exposures be limited to 100 mRem/year,
a level well below the upper limit of
5000 mRem/year approved in by the
President in 1987 ("Radiation Exposure
Guidance to Federal Agencies for
Occupational Exposure", as cited in
USEPA 1994b). Based on limited data,
it appears that 100 mRem/year is a
maintainable objective within water
treatment plants treating for radon or
other contaminants. Exposure level
monitoring and mitigation through a
combination of air monitoring and
ventilation has been demonstrated to be
feasible and relatively inexpensive (e.g.,
Reichelt 1996).
Regarding the effects on water
corrosivity and the impacts of costs of
corrosion control measures, this notice
presents much more detail on EPA's
assumptions. Corrosion control
measures are included in national cost
estimates and are discussed in this
notice. Case study information on
corrosion control costs associated with
aeration are included in the Radon
Technologies and Costs document
(USEPA 1999h).
(c) GAC. Two commenters noted that
the option for use of granular activated
carbon (GAC) did not address potential
problems with radioactivity buildup in
the carbon. In consideration of
treatment methods the two commenters
saw no mention of the cost of disposal
of GAC used for radon removal. If not
replaced in time it will become a low
level radioactive waste because of Lead
210 and will become difficult to dispose
of. Other issues that need to be
addressed include: will the unit require
special shielding; may the charcoal bed
be required to have a radioactive
materials license from the State; and
how may radioactive carbon be
disposed of?
EPA Response 5-3
Special considerations regarding GAC
operations, maintenance, and ultimate
GAC unit disposal are discussed in
some detail in Section VIII. A of this
notice, including discussions of the
radiation hazards involved and steps
that can be taken to ameliorate these
hazards. GAC disposal costs are
included in the operations and
maintenance costs in the model used for
cost estimates. Comparisons of modeled
GAC capital and operations &
maintenance cost estimates to actual
costs reported in case studies are
included in Section VIII of this notice.
EPA would like to strongly emphasize
that carbon bed lifetimes (carbon bed
replacement rates) should be designed
to preclude situations where disposal
becomes prohibitively expensive or
technically infeasible.
Recently, the American Water Works
Association Research Foundation has
published a study on the use of GAC for
radon removal, which includes
discussions of the issues described
previously, that concludes that GAC is
a tenable treatment strategy for small
systems when used properly under the
appropriate circumstances (AWWARF
1998a). AWWARF also reviewed the
proper use of GAC for radon removal in
its recent review of general radon
removal strategies (AWWARF 1998b).
When the final radon rule is
promulgated, a guidance manual will be
published describing technical issues
and solutions for small systems
installing treatment.
One commenter suggested that the
costs for GAC seemed to be too high.
The figures used in the analysis could
be two orders of magnitude above the
costs actually seen by the systems.
EPA Response 5-4
EPA agrees that its GAC cost estimates
seem to be very high, as compared to
case studies (USEPA 1999h, AWWARF
1998b). EPA agrees with others (e.g.,
AWWARF 1998a and b) that GAC will
probably be cost-effective for very small
systems or in a point-of-entry mode.
This issue is addressed in the preamble
(Section VIII.A) and GAC will be
included as a small systems compliance
technology.
(d) Regionalization. Two commenters
questioned a cost of $280,000 as the
single cost for regionalization.
Assuming $100/foot for an
interconnection, these costs would
equate to an interconnection of 2800
feet which seems low. Systems are
usually separated by more than one-half
mile. A range of costs may need to be
considered rather than a single number.
Smaller systems will have smaller costs,
while large systems will have larger
costs. Thus, the charge for
regionalization should vary by systems
size. Also, EPA should clarify whether
or not regionalization charges include
yearly operation and maintenance costs.
EPA Response 5-5
EPA agrees that the costs of
regionalization would be expected to
change with water system size, but, as
indicated in the assumptions outlined
in the February 26, 1999 HRRCA, EPA
assumed that only very small systems
(those serving fewer than 500) would
resort to regionalization in response to
the radon rule. Given that the proposed
rule involves a multi-media approach
that greatly encourages small systems to
choose the AMCL of 4000 pCi/L in
conjunction with a multi-media
mitigation program, EPA expects that
very few systems would choose
regionalization as an option. EPA
believes that the assumption that 1 out
of 100 small systems that choose the
MCL option would regionalize is
conservative and would only be
exercised if regionalization were cost-
competitive with other options, except
under very unusual circumstances.
Since the estimate of $250,000 is much
more expensive than any other option
modeled for those size categories, this
assumption supports the situation
where small systems may be expected to
entertain this option, i.e., where
regionalization does not involve piping
water over great distances. This figure is
based on a simple estimate using the
cost of installed cast iron pipe at $44 per
linear foot (an average cost for several
pipe relevant pipe diameters) from the
1998 Means Plumbing Cost Data and
applying 20 percent for fittings,
excavation, and other expenses to arrive
at an estimate of $53 per linear foot, or
$280,000 per linear mile. Purchased
water costs ($/kgal) were assumed to
equal the pre-regionalization costs of
production ($/kgal), merely as a
modeling convenience. In some cases,
purchased water costs may be higher, in
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some cases lower. Although EPA does
not have many case studies to support
this assumption, it does have
information on a Wisconsin case study
in which a small water system (serving
375 persons) regionalized to connect to
a near-by city water supply in 1995,
partly in response to a radium violation.
The capital costs for this regionalization
case study was $225,000. There were no
reported operations costs associated
with the purchased water. EPA makes
no claims that this case study is typical,
but rather that this is the best
assumption that it could make based on
the available information. Since this is
a minor part of the over-all national
costs and since a more extensive
modeling of the costs of regionalization
would necessitate a much more detailed
modeling of the additional benefits of
regionalization (which were not
included), this assumption is
maintained in the Regulatory Impact
Assessment for this proposed rule.
One commenter also questioned the
feasibility of regionalization for many
systems. There are very few locations
where this is possible and just hooking
up to a larger supplier is not practical.
Many have systems that are not
acceptable to a larger supplier and many
larger suppliers won't accept the
liability involved in taking over the
small system.
EPA Response 5-6
Since most small systems are
expected to adopt the AMCL/MMM
option, EPA's regionalization
assumption (1 percent of the minority of
small systems that choose the MCL
option) is consistent with this
commenter's concern. Nevertheless,
administrative regionalization is often
feasible, in particular when this does
not require new physical connections,
and may be an important element of the
long term compliance strategy for a
number of systems.
(e) Pre-treatment to reduce iron/
manganese levels. The majority of the
commenters disagreed with EPA's
assumptions on the removal of Fe/Mn.
It was assumed that essentially all
systems with high Fe/Mn levels are
likely to already be treating to remove
or sequester these metals. Therefore,
costs of adding Fe/Mn treatment to
radon removal were not included in the
February, 1999 HRRCA (64 FR 9560).
Commenters suggested that this is a
poor cost assumption, in that there are
many systems above the secondary MCL
for Fe/Mn that do not treat. Of those that
sequester, commenters suggested that
existing treatment is ineffective once Fe/
Mn has been oxidized. Therefore,
filtration as well as disinfection would
be required for that type of system at a
significant additional cost that needs to
be considered when reviewing the
HRRCA.
If Fe/Mn is present in the source
water, removal treatment will be
necessary to prevent fouling of the
radon removal system. Disposal for the
Fe/Mn residuals also presents a special
problem with its associated costs. One
commenter noted that by not including
the costs of Fe/Mn removal, EPA is
making a poor assumption and may be
underestimating costs.
EPA Response 5-7
EPA recognized that not quantifying
the costs associated with the control of
dissolved iron and manganese (Fe/Mn)
was potentially a poor assumption, and
indicated that this assumption would be
revisited for the Regulatory Impact
Analysis supporting this proposed rule.
However, EPA also indicated that
national costs and average per system
costs would probably not be
significantly affected in addressing this
issue. While EPA's current modeling
results support this conclusion, EPA has
included the costs of adding chemical
stabilizers (which minimize Fe/Mn
precipitation and also provide, for
corrosion control in some cases) by 25
percent of small systems that treat and
15 percent of large systems that treat. A
more detailed discussion on the
inclusion of Fe/Mn treatment costs is
provided in Section VIII of the
preamble.
To further support its position on Fe/
Mn control, EPA has also (1) analyzed
case studies of systems aerating, which
include Fe/Mn control measures for a
small minority of the systems, (2)
performed an analysis of the co-
occurrence of radon with Fe/Mn in
ground water, and (3) performed an
uncertainty analysis on costs, which
includes a simulation of more expensive
control measures for Fe/Mn. All of these
results are also discussed in Section VIII
of the preamble.
(f) Post treatment-disinfection. Many
commenters stated that EPA's
assumption that the majority of
groundwater systems already disinfect
is false. Some commenters felt this is
inconsistent with the Ground Water
Rule estimates. Commenters suggested
that analyses supporting the proposed
groundwater rule estimate that only 50
percent of CWSs and only 25 percent of
NTNCWSs disinfect, while Table 5-2 of
the HRRCA suggests that the majority of
water systems using groundwater
already disinfect and that 20 percent of
all water systems serving 3,300 or
greater have aeration or disinfection in
place.
EPA Response 5-8
The cited analyses supporting the
Ground Water Rule (GWR) were
conducted using occurrence estimates at
the level of individual entry points at
water systems. The February 1999
Radon HRRCA was conducted using
occurrence estimates at the level of
water systems. The GWR and radon
analyses use the same data source for
estimating their respective disinfection-
in-place baselines, the 1997 Community
Water System Survey (USEPA 1997a),
the only source of information of this
type that is based on a survey that was
designed to be statistically
representative of community water
systems at the national level. The GWR
used a disinfection-in-place baseline for
entry points and the radon HRRCA used
a disinfection-in-place baseline for
water systems.
The most desirable level of analysis is
at the entry point, but the only
nationally representative data source for
radon, the National Inorganics and
Radionuclides Survey, was conducted at
the water system level (samples were
taken at the tap), which provides no.
information about radon occurrence at
individual entry points within water
systems. Radon intrasystem (within
system) occurrence variability studies
were not available for the analyses
supporting the February 1999 radon
HRRCA. In the interim between
publishing the radon HRRCA and
today's proposal, EPA has conducted
radon intrasystem variability studies
(based on studies other than NIRS) and
has used the results of this study to
estimate radon occurrence at the entry
point level. The current Regulatory
Impact Analysis supporting the Radon
rule was conducted at the entry point
level, consistent with the Ground Water
Rule.
EPA Response 5-9
The additional costs to which this
commenter is referring, namely the costs
of storage for contact time, are included
in the costs of the clearwell, which are
included in the costs of the aeration
process. In the scenarios in which
disinfection is assumed, EPA does NOT
assume that the systems have a
clearwell in place and does include the
costs of adding a clearwell for collection
of water after aeration and for five
minutes of disinfection contact time,
which EPA believes to be sufficient for
4-log viral de-activation.
(g) Monitoring costs. One commenter
expressed concerns regarding EPA's
calculation of monitoring costs. The
commenter suggested that EPA grossly
underestimated the number of wells per
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59341
different water system size in Table 5.4
of the HRRCA (64 FR 9585). page 9585
and in Appendix D of the HRRCA. As
a result, monitoring costs need to be
recalculated by EPA.
EPA Response 5-10
See EPA Response 1-2 for EPA's
approach to determining the number of
wells per system,
(h) Choice of treatment responses. As
noted previously in Section G, one
commenter questioned whether
chlorination would always be the
disinfection technology of choice, as
well as EPA's assumption that existing
chlorination practices would not have to
be augmented if aeration were installed.
Other commenters on cost issues
questioned the feasibility and
practicability of some technologies on
cost grounds,
EPA Response 5-11
EPA assumed that chlorination would
be the "typical" disinfection technology
chosen to model the "average treatment
costs" (or "central tendency costs").
There is no way to know beforehand
exactly how the universe of water
systems will behave in response to a
given situation, so EPA believes that the
best way to model national compliance
costs is to estimate these central
tendency costs, then to use statistical
tools to capture the fact that "real world
costs" will spread around the central
tendency costs, rather than being
equivalent to them. By estimating the
central tendency costs and using
statistical uncertainty to capture "real
world" variability (including variability
in disinfection costs), EPA believes that
this modeling technique allows for the
fact that real systems will behave in a
variety of ways, including things like
choosing different disinfection
technologies,
(I) Site and system costs. A number of
issues were raised concerning site and
system cost estimates. Several
commenters suggested that the HRRCA
severely underestimated the number of
sites per system, citing the difference
between the CWSS data and HRRCA
assumptions. Several commenters noted
that the numbers of sources per system
in Table 5-4 of the HRRCA for systems
serving 10,001—50,000 were too low.
One commenter maintained that the
number of sources per system could
have a significant impact on national
treatment costs.
EPA Response 5-12
EPA agrees that the distribution of the
number of sites per system was
underestimated and has revised its
estimate to be consistent with the
CWSS. However, it should be noted that
while the distribution of the sites per
system actually does have an impact on
national treatment costs, this impact is
significantly mitigated by the fact that
the flow per well being treated
decreases proportionally as the
estimated number of wells per system
increases.
0) Aggregated national costs. Several
commenters agreed that the national
average costs masked significant
impacts on small systems. When small
systems are considered, the financial
impact is large; in some cases, water
bills could double or triple. Providing
individual system costs is critical so
that utilities can explain to their
customers the specific costs and benefits
for that specific system.
EPA Response 5-13
EPA estimates household impacts for
small systems that install treatment (per
household costs) by estimating the costs
that small systems would face (per
system costs), then spreading these costs
over the customer base (population
served). As demonstrated in the
HRRCA, household costs for small
systems are expected to be many times
higher for very small systems than for
larger systems. In listing small systems
compliance technologies for radon, EPA
estimated the impacts on small systems
by estimating the per system costs and
the per household costs and comparing
them to affordability criteria, as
described in this notice and in the
references cited. However, it should also
be noted that the vast majority of small
systems are expected to comply with the
AMCL/MMM option, rather than the
MCL option. Under these
circumstances, less than 1 percent of
small systems would have to take
measures to reduce radon levels in their
drinking water.
(k) Costs to CWSs. Small systems will
bear a significant percentage of the costs
for implementing a radon MCL, but will
only accrue a small proportion of the
benefits. At the 300 pCi/L, the two
categories of smallest systems combined
would receive 5.6 percent of the benefits
at this level, but would pay 42 percent
of the total costs. Several commenters
indicated that the benefitcost ratio for
small systems was thus highly
unfavorable.
EPA Response 5-14
EPA recognizes that small systems
experience similar benefits per customer
as large systems, but, due to economies
of scale (higher treatment costs per
gallon treated), experience much higher
costs per customer compared to large
systems. This, of course, leads to higher
costs at the same level of benefits.
However, EPA has also recognized that
radon is a multi-media problem in
which most of the risk is presented from
sources other than drinking water and
has addressed this fact by designating
the AMCL/MMM option as the preferred
option for small systems. This will
greatly lower the per customer costs
faced by small systems and may lead to
greater total benefits that accrue to small
systems.
(1) Costs to consumers/households.
One commenter thought that the
household consumption presented in
the HRRCA (83,000 gal/year) is too low.
This is an understatement because
treatment would be required for all
water produced, not just water
consumed by households.
EPA Response 5-15
EPA does not assume that per system
costs are based only on residential water
use and so does not miscalculate water
prices in the way described by the
commenter. To determine the price of
water, EPA calculates per system costs
based on both residential and non-
residential consumers (which is the
main reason EPA calculates costs for
privately-owned and publically-owned
separately, i.e., because they have
different ratios of residential to non-
residential consumption). These per
system costs determine the costs per
gallon treated (not per gallon consumed)
to determine the water price. The water
price may then be used in conjunction
with the household consumption to
estimate the water bills faced by
households, since they do pay by the
gallon consumed (and not by the gallon
treated).
(m) Application of radon related costs
to other rules. Several commenters
addressed the need to include the
cumulative impact of regulations in the
RIA. The incremental costs of the
regulations for radon, arsenic, and
groundwater systems could
substantially change the affordability
analysis for small systems. Thus,
treatment decisions need to be made
with an understanding of all the
requirements that must be met so that
treatment systems can be designed to
meet all requirements. One commenter
suggested a multi-rule cost and benefit
analysis to capture the true costs
incurred by these systems.
EPA Response 5-16
The cumulative effects of rules are
captured in EPA's "affordability
criteria", which are described in the
publicly available 1998 EPA document,
"National-Level Affordability Criteria
Under the 1996 Amendments to the Safe
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Drinking Water Act" (USEPA 1998e).
These small system affordability criteria
take into account how much consumers
are currently paying for typical water
bills. Since the upcoming regulations
will affect these amounts, the
cumulative effect of the costs of the
rules will be explicitly considered in the
affordability determinations for small
systems as new rules are issued. EPA
recognizes that its method of basing
affordability determinations on average
costs does not address the situation of
systems that have significantly above
average costs because they must treat for
a number of contaminants
simultaneously. EPA believes this
approach is consistent with the
requirements of SDWA for identifying
affordable small system technologies
and notes that other SDWA mechanisms
may be used to address situations where
systems incur considerably higher costs.
6. Cost and Benefit Results
The main concern of many of the
comments regarding this section
suggested that the costs of controlling
radon in drinking water far outweighed
possible benefits, especially for small
systems. Controlling indoor air radon
was identified as a better use of
regulatory and economic resources by
several commenters. Commenters also
had concerns regarding how national
total costs, benefits, and economic
impacts were calculated, and regarding
the uncertainties in costs and benefits
estimates.
(a) Overview of analytical approach.
Many commenters indicated that the
cost-benefit analysis was skewed toward
overestimating benefits, and/or omitted
important cost elements. One concern
shared by many of these commenters
was that the cost-benefit calculations
were biased because mitigation costs,
but not health benefits, were
discounted. A commenter also indicated
that too many assumptions had been
used to derive cost and benefit
estimates.
EPA Response 6-1
The radon cost benefit analysis was
performed according to EPA guidelines,
in an attempt to fairly portray both costs
and benefits, and not leave out
important categories of either costs or
benefits.
Annual mitigation costs are compared
to annual benefits for the cost benefit
comparisons. Annual mitigation costs
consist of annualized capital costs plus
yearly operating costs. Annualized costs
are computed under the assumption that
capital expenditure are made up front,
with borrowed funds, and the payments
are then annualized over a period of
twenty years. Changes in the rate of
interest used in the annualization
process will change the annual cost, just
like a mortgage will change with
different rates of interest. Adding yearly
operating costs for one year to
annualized capital costs for one year
gives the total annual cost for the year.
The issue of discounting of benefits is
discussed in Section XIII.D.
In any modeling process, assumptions
must be made. To model costs and
benefits, assumptions about those costs
and benefits must be made. The number
of assumptions needed depends on the
complexity of the problem addressed,
and the time and information available
to address it. We would be interested in
information that might inform our
modeling, particularly addressing
improvements that could be made to
specific assumptions.
(b) MCL decision-making criteria. A
commenter requested that EPA define
explicit decision-making criteria for
setting MCL levels, to assure that the net
benefit to society is positive.
Another commenter indicated that,
because drinking water radon accounts
for a small portion of total risks, EPA
should consider the relative costs and
benefits of mitigation on a case-by-case
basis at individual systems before
making regulatory decisions. A
commenter suggested that if the latency
of cancer risk reduction and benefits
were discounted properly, the national
cost-benefit ratios for radon mitigation
would be between 5:1 and 9:1. They
stated that EPA should not promulgate
a rule with net negative benefits,
especially in light of the large economic
impacts on small systems.
A commenter indicated that the cost-
benefit ratios in Table 6-13 of the
HRRCA imply that regulation of radon
in ground water is not justified. They
point out that systems serving 25-3,300
people incur at least 56 percent of the
costs and generate at most 21 percent of
the total benefits at all MCLs. They say
that justifying radon control in drinking
water by adding in the benefits of MMM
programs is not justified. Another
commenter also maintained that the
small, localized benefits of controlling
radon exposures do not come near to
justifying the costs of mitigation.
One commenter said that the decision
to set an MCL must take into account
the level of uncertainty in cost and
benefit estimates. Another commenter
suggested that the Agency undertake a
quantitative uncertainty analysis of the
cost and benefit estimates. Two
commenters said that the closeness of
the cost and benefit estimates should be
considered in setting a regulatory level;
if uncertainty is large, a less stringent
MCL would be justified.
EPA Response 6-2
EPA has included a detailed
discussion on its decision-making
criteria for setting the MCL for radon in
drinking water in the preamble for the
proposed rulemaking (see Section
VII.D).
(c) National costs of radon mitigation.
Two commenters indicated that the
national cost estimates obscured the
high costs that would be borne by
individual systems. One commenter
indicated that radon variability in
individual wells increases the
uncertainty in the cost estimates.
Another commenter said that cost
estimates should include the costs of
more frequent lead and copper
exceedences brought about by increased
aeration. Other comments on specific
cost elements were summarized in
Section 5. One commenter requested
that EPA regionally disaggregate cost
and benefit estimates because of
structural and operational differences
among water systems. Another
commenter suggested that EPA should
conduct a more comprehensive analysis
of costs and benefits, including cost
elements not currently addressed, such
as waste management.
EPA Response 6-3
The national costs include an
uncertainty analysis which captures the
regional spread in treatment costs. In
addition, EPA has estimated total
national costs by assuming that most
systems will face "typical costs", but
that some will face "high side" and
some "low side" treatment costs. These
"high side" and "low side" cost
differences are largely based on regional
considerations, like the costs of land,
structure, and permitting.
(d) Incremental costs and benefits.
One commenter indicated that the
incremental costs and benefits of the
various MCL options should be
presented in the HRRCA. They question
the affordability of radon mitigation for
small systems.
EPA Response 6-4
EPA has provided an analysis of the
incremental costs and benefits of each
MCL option in the HRRCA. See Table 6-
7, Estimates of the Annual Incremental
Costs and Benefits of Reducing Radon in
Drinking Water, in the February 1999
HRRCA.
(e) Costs to community water systems.
One commenter said that a more
accurate picture of costs and impacts
(inclusive of State and local costs)
would be needed to make a reasonable
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risk management decision. Another
commenter suggested that EPA should
consider the cumulative costs of all
drinking water regulations on drinking
water systems.
EPA Response 6-5
See EPA Response 5-14 for EPA's
approach to determining the costs to
CWSs. Administrative costs to States
were not included in the February 1999
HRRCA, but have been added in the RIA
for the proposed rule.
(f) Costs and impacts on households.
One commenter asked that EPA explain
how it determined what was an
"acceptable" percentage of household
income that would go to radon
mitigation. Another commenter
indicated that household costs should
be compared to benefits at the local,
rather than national, level, because
benefits and costs are realized locally. A
commenter indicated the median
household incomes for households
served by different system sizes are not
shown; they also suggested that
household costs as a percentage of
income were underestimated in Table
6-11 of the HRRCA. One commenter
said that expressing household impacts
as a proportion of annual income
trivializes it and that costs could more
meaningfully be compared to other
types of household expenses (i.e., food,
rent). Several commenters also noted
the significant impact the costs could
have on customer water bills for small
systems.
EPA Response 6-6
See EPA Response 5-15 for EPA's
approach to determining the costs to
households.
(g) Summary of costs and benefits.
Comments from one organization
regarding the cost-benefit comparison
for radon mitigation were typical of
those received from other sources. They
cited the NRC/NAS report as indicating
that only two percent of population risk
came from drinking water and
questioned whether the high costs of the
rule could justify the small benefits
obtained. They said that the cost-benefit
comparison did not justify regulating
radon in ground water, especially in
small systems, where costs were highest
and benefits lowest. Another commenter
also pointed out that it would be more
cost-effective to regulate radon in indoor
air than in drinking water and further
maintained that spending resources to
mitigate radon in water could actually
result in reduced public health
protection. They point out that the cost-
benefit ratios for the smallest systems
range from 20:1 to 50:1, and suggest that
these ratios, rather than the greater
aggregate costs to large systems, should
be persuasive in regulatory decision
making. Other commenters suggested
the high cost-benefit ratios did not
justify the regulation of small systems.
EPA Response 6-7
The 1996 Safe Drinking Water Act
Amendments require EPA to propose a
regulation for radon in drinking water
by August 1999. The options for small
systems, proposed for public comment
in this rulemaking, represents EPA's
efforts to address stakeholder comments
concerning small systems.
7. Multimedia Mitigation Programs
(a) Multimedia programs. Two
commenters indicated that setting the
AMCL at 4,000 pCi/L was justifiable.
They suggested that EPA should utilize
on MMM approach as the primary tool
for reducing radon risks, and not use the
SDWA to force the States to develop
MMM programs.
Several commenters noted that the
MCL EPA selects should be justifiable
on cost-benefit grounds, with the MMM
program serving as a supplemental
program to allow States to achieve
greater risk reduction at less cost.
Another commenter suggested the
multimedia approach allowed under the
1996 amendments to the SDWA should
not be used with regard to radon-222 in
water.
EPA Response 7-1
The requirement for implementation
of an EPA-approved MMM program in
conjunction with State adoption of the
AMCL is consistent with the statutory
framework outlined by Congress in the
SDWA provision on radon. As
proposed, States may choose either to
adopt the MCL or the AMCL and an
MMM program. EPA recommends that
small systems comply with an AMCL of
4,000 pCi/L and implement a MMM
program. See section VII.D for
background on the selection of the MCL
and AMCL.
Two commenters believe the radon
regulation may result in litigation
against water utilities, local, and State
governments if systems comply with the
AMCL rather than the MCL. As a result,
some water utilities could choose to
comply with the more stringent MCL
rather than face potential litigation for
meeting a "less stringent standard,"
regardless of the increased public health
protection. According to one
commenter, problems will arise when
both the AMCL and the MCL are
required to appear on the annual
Consumer Confidence Report. The
public will view the AMCL as an
attempt by the water industry to get
around the MCL. This will leave the
water utility vulnerable to toxic tort
lawsuits. Because of these problems, the
concept of an MMM program/AMCL is
not as attractive as it once appeared.
EPA Response 7-2
EPA is aware of this concern and the
risk communication challenges of two
regulatory limits for radon in drinking
water. However, the SDWA framework
requires EPA to set an alternative
maximum contaminant limit for radon if
the proposed MCL is more stringent
than the level of radon in outdoor air.
It is important to recognize that in State
primacy applications for oversight and
enforcement of the drinking water
program, States choosing the MMM
approach will be adopting 4,000 pCi/L
as their MCL. In addition, as part of the
proposed rule, EPA will be amending
the Consumer Confidence Reporting
Rule to reflect the proposed regulation
for radon. Under § 141.153 of the
proposed radon rule, a system operating
under an approved multimedia
mitigation program and subject to an
Alternative MCL (AMCL) for radon must
report the AMCL instead of the MCL
whenever reporting on the MCL is
required.
Another commenter questioned the
need for regulating radon in water
below 3,000 pCi/L, and maintained that
there is no conceivable reason to
regulate it at 100 pCi/L, with or without
an MMM program.
EPA Response 7-3
See EPA Response 6-2 for EPA's
decision criteria for setting an MCL.
(b) Implementation scenarios
evaluated. One commenter feels that a
"desk top review" of States likely to
adopt an MMM program would give
more useful estimates of MMM
acceptance than the HRRCA
assumptions of zero, 50 percent, and
100 percent adoption of MMM
programs. This commenter felt that for
an MMM program to be productive, two
things are necessary: (1) relatively high
radon concentration in water and (2)
relatively high radon in indoor air.
EPA Response 7-4
For the purposes of the HRRCA, EPA
made these assumptions as a straight
forward approach for assessing overall
cost implications of MMM. States are
not required to make their
determinations on whether to adopt the
MMM approach until after the rule is
final in August 2000. Therefore, EPA
did not have this information available
when developing the HRRCA, nor does
EPA have this information at this time.
However, discussions with many State
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drinking water and radon program staff
suggest that many States are seriously
considering the MMM approach.
EPA expects that MMM programs will
be able to achieve indoor radon risk
reduction even in areas of low radon
potential. It is important to keep in
mind that the only way to know if a
house has elevated indoor radon levels
is to test it. Many homes in low radon
potential areas have been found with
levels well above EPA's action level of
4 pCi/L, often next door to houses with
very low levels. EPA estimates that
about 6 million homes in the U.S. of the
83 million homes that should test are at
or above 4 pCi/L. To date only about 11
million homes have been tested. In
addition, EPA is not requiring State
MMM program plans to precisely
quantify equivalency in risk reduction
between radon in drinking water and
radon in indoor air.
(c) Multimedia mitigation cost and
benefit assumptions. Two commenters
indicated that, even if it is not known
how the MMM programs will be funded,
the costs of administering such
programs should be included in the
HRRCA. Several commenters expressed
concerns regarding the estimated cost of
$700,000 per fatal cancer averted. One
commenter felt that using this value is
far too optimistic, indicating that the
cost of radon risk reduction under State-
mandated MMM programs will
significantly exceed present costs under
the voluntary system. To get the greatest
risk reductions at the lowest costs,
MMM program should focus on the
houses with the highest radon
concentrations. Another commenter
recommended that EPA develop an
MMM program that is better than the
existing voluntary programs and further
reduces the cost per fatal cancer
avoided. The commenter also requested
that EPA supply background
information supporting use of this
single MMM program cost estimate.
EPA Response 7-5
EPA is required under the UMRA to
assess the costs to States of
implementing and administering both
the MCL and the MMM/AMCL. EPA has
addressed these costs in the preamble of
the rule.
EPA believes that the criteria for EPA
approval of State MMM program plans
will augment and build on existing State
indoor radon programs and will result
in an increased level of risk reduction.
As part of developing the 1992 "A
Citizen's Guide to Radon," EPA
analyzed the risk reductions and costs
of various radon testing and mitigation
options (USEPA 1992b). Based on these
analyses, a point estimate of the average
cost per life saved of the current
national voluntary radon program was
used as the basis for the cost estimate of
risk reduction for the MMM option. EPA
had previously estimated that the
average cost per fatal lung cancer
avoided from testing all existing homes
in the U.S. and mitigation of all those
homes at or above EPA's voluntary
action level of 4 pCi./L is approximately
$700,000. This value was originally
estimated by EPA in 1991. Since that
time there has been an equivalent offset
between a decrease in testing and
mitigation costs since 1992 and the
expected increase due to inflation in the
years 1992-1997.
One commenter stated that
experiences in Massachusetts showed
that the costs of incorporating passive
radon resistant construction techniques
is about the same as current prices for
marginal quality (active) radon
mitigation in existing buildings, and
disputed the HRRCA statement that
passive techniques are much less
expensive. The commenter supported
the NAS findings that the effectiveness
of these techniques in normal
construction practice is uncertain.
EPA Response 7-6
Builders have reported costs as low as
$100 to install radon resistant new
construction features which is
significantly less than the $350—$500
that was derived in EPA's cost-
effectiveness analysis of the radon
model standards. The cost of materials
alone for the passive system will always
be less than the cost for an active system
which includes the cost of a fan. In
many areas, the majority of the features
for radon-resistant new construction are
already required by code or are common
building practice, such as an aggregate
layer, "poly" sheeting, and sealing and
other weatherization techniques. The
only additional cost is associated with
the vent stack consisting of PVC pipe
and fittings. In those areas where gravel
is not commonly used, builders can use
a drain tile loop or other alternative less
costly than gravel to facilitate
communication under the slab. EPA
estimates that the cost to mitigate an
existing home ranges from $800 to
$2,500 with an average cost of $1,200.
(d) Annual costs and benefits of MMM
program implementation. Several
concerns were raised regarding the costs
and benefits associated with MMM
program implementation. One
commenter suggested that the MMM
program description in the HRRCA
provides essentially no guidance on the
point from which additional risk
reduction due to MMM will be
measured.
EPA Response 7-7
The HRRCA was not intended to
include a discussion and description of
the criteria for EPA approval of State
MMM programs. Rather, proposed
criteria are presented in this proposed
rule. EPA's proposed criteria do not
entail a determination by the State of
the level of indoor radon risk reduction
that has already occurred ("baseline") as
the basis for determining how much
more risk reduction needs to take place.
Rather States, with public participation,
are required to set goals that reflect State
and local needs and concerns.
Another commenter states that EPA
has underestimated the benefits of an
MMM program. The HRRCA registers
only the benefits gained in relation to
water being treated to the MCL.
However, according to EPA's figures,
MMM benefits are expected to be much
higher than those achieved by
mitigating water alone.
EPA Response 7-8
EPA anticipates that MMM programs
will result in sufficient risk reduction to
achieve "equal or greater" risk
reduction. A complete discussion on
why MMM is expected to achieve equal
or greater risk reduction is shown in
Section VLB of today's preamble. For
the purposes of the HRRCA analyses,
EPA made the conservative assumption
that the level of risk reduction would at
least be "equal" to that achieved by
universal compliance with the MCL.
8. Other Key Comments
(a) Omission of non-transient non-
community water systems (NTNCWSs).
Eleven commenters criticized EPA's
failure to include NTNCWSs in the
HRRCA. Three commenters indicate
that failure to include NTNCWSs
grossly underestimates costs of radon
mitigation. Another commenter also
suggests that NTNCWSs should be
included in the HRRCA, to provide a
better picture of both costs and benefits.
Two commenters would also like
NTNCWSs included because impacts on
these systems are likely to be high.
Other commenters maintain that
excluding NTNCWSs skews benefit-cost
analyses in favor of regulation. Another
commenter indicates that NTNCWSs,
because of the type of wells and aquifers
that they draw from, will be most
affected by a radon rule.
EPA Response 8-1
Partly as a result of concerns raised by
commenters, and partly as a result of its
own preliminary analysis of exposure
and risk, EPA is not proposing that
NTNCWSs be covered by this rule. A
more complete discussion of this issue
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59345
Is included in the preamble for the
proposed rule. EPA has conducted a
preliminary analysis on exposure and
risks to NTNCWSs and is asking for
public comment on this preliminary
analysis and on the proposed exclusion
of NTNCWSs. An analysis of the
potential benefits and costs of radon in
drinking water for NTNCWSs is
included in the docket for this proposed
rulemaking. (USEPA 1999m)
XIV. Administrative Requirements
A. Executive Order 12866: Regulatory
Planning and Review
Under Executive Order 12866,
"Regulatory Planning and Review" (58
FR 51.735 (October 4. 1993)), the
Agency must determine whether the
regulatory action is "significant" and
therefore subject to OMB review and the
requirements of the Executive Order.
The Order defines "significant
regulatory action" as one that is likely
to result in a rule that may:
(1) have an annual effect on the
economy of SI 00 million or more or
adversely affect in a material way the
economy, a sector of the economy,
productivity, competition, jobs, the
environment, public health or safety, or
State, local, or tribal governments or
communities;
(2) create a serious inconsistency or
otherwise interfere with an action taken
or planned by another agency;
(3) materially alter the budgetary
impact of entitlements, grants, user fees,
or loan programs or the rights and
obligations of recipients thereof; or
(4) raise novel legal or policy issues
arising out of legal mandates, the
President's priorities, or the principles
set forth in the Executive Order.
Pursuant to the terms of E.O. 12866,
it has been determined that this rule is
a "significant regulatory action". As
such, this action was submitted to OMB
for review. Changes made in the
proposal in response to OMB
suggestions or recommendations will be
documented in the public record.
B, Regulatory Flexibility Act (RFA)
I. Today's Proposed Rule
Under the Regulatory Flexibility Act
(RFA), 5 U.S.C. 601 etseq., as amended
by the Small Business Regulatory
Enforcement Fairness Act (SBREFA),
EPA generally Is required to conduct a
regulatory flexibility analysis describing
the impact of the regulatory action on
small entities as part of rulemaking.
Today's proposed rule may have
significant economic impact on a
substantial number of small entities and
EPA has prepared an Initial Regulatory
Flexibility Analysis (IRFA). In addition,
when preparing an IRFA, EPA must
convene a Small Business Advocacy
Review (SBAR) Panel. A discussion of
the Panel's recommendations and EPA's
response to their recommendations is
shown in Section 6.
2. Use of Alternative Small Entity
Definition
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
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.
3. Background and Analysis
The RFA requires EPA to address the
following when completing an IRFA: (1)
describe the reasons why action by the
Agency is being considered; (2) state
succinctly the objectives of, and legal
basis for, the proposed rule; (3) describe,
and where feasible, estimate the number
of small entities to which the proposed
rule will apply; (4) describe the
projected reporting, record keeping, and
other compliance requirements of the
rule, including an estimate of the classes
of small entities that will be subject to
the requirements and the type of
professional skills necessary for
preparation of reports or records; (5)
identify, to the extent practicable, all
relevant Federal rules that may
duplicate, overlap, or conflict with the
proposed rule; and (6) describe any
significant alternatives to the proposed
rule that accomplish the stated
objectives of applicable statutes while
minimizing any significant economic
impact of the proposed rule on small
entities. EPA has considered and
addressed all of the previously
described requirements. The following
is a summary of the IRFA.
The first and second requirements are
discussed in Section II of this Preamble.
The third, fourth, and sixth
requirements are summarized as
follows. The fifth requirement is
discussed under Section VIII.A.2 of this
Preamble in a subsection addressing
potential interactions between the radon
rule and upcoming and existing rules
affecting ground water systems.
4. Number of Small Entities Affected
EPA estimates that 40,863 ground
water systems are potentially affected by
the proposed radon rule, with 96
percent of these systems serving less
than 10,000 persons. Of the 39,420
small systems potentially affected, EPA
estimates that 1,761 (4.4 percent) small
systems will have to modify treatment
(install treatment technology) to comply
with the AMCL. The proposed rule
recommends that small systems meet
the 4,000 pCi/L AMCL and implement
a multimedia mitigation (MMM)
program if their State does not
implement a MMM program. Small
systems may also choose to comply with
the MCL rather than implement an
MMM program. As Table XIV. 1
indicates, water mitigation
administration costs for small systems
remain the same under any State MMM
program adoption scenario. However,
small systems located in States that do
not implement a MMM program must
develop and implement their own
MMM program for the population they
serve (unless they choose to comply
with the MCL), thus increasing their
costs. Additional MMM implementation
scenarios have been analyzed in the RIA
(USEPA 1999f) which is included in the
docket for this proposed rulemaking.
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TABLE XIV.1.—ANNUAL WATER MITIGATION AND MMM PROGRAM COSTS TO SMALL SYSTEMS
[$Millions, 1997]
Cost description
Water Mitigation Costs1
Total Capital Costs
Total Annual Costs2
Water Mitigation Administration Costs
Multimedia Mitigation Program Costs3
Total Small System Costs per Year
100% 'of states
adopt MMM
H-JO C
0-J 0
C 0
37.1
50% of states
adopt MMM
92.4
1 Costs to small systems to mitigate water to the AMCL of 4,000 pCi/L.
2 Includes annual capital costs, monitoring costs, and operation and maintenance costs.
3 Does not include the costs of testing and mitigating homes.
5. Proposed Rule Reporting
Requirements for Small Systems
The proposed radon rule requires
small systems to maintain records and
to report radon concentration levels at
point-of-entry to the water system's
distribution system. Small systems are
also required to provide radon
information in the Consumer
Confidence Report, and if the system is
implementing its own MMM program,
reports on progress to the goals outlined
in the system's MMM program plan.
Radon monitoring and reporting for
water mitigation will be required on a
quarterly basis for at least one year, but
thereafter the frequency may be reduced
to annually or once every three years
depending on the level of radon present
(see Section VIII.E). Other existing
information and reporting requirements,
such as Consumer Confidence Reports
and (proposed) public notification
requirements, will be marginally
expanded to encompass radon along
with other contaminants (see Section X).
As is the case for other contaminants,
required information on system radon
levels must be provided by affected
systems and is not considered to be
confidential. The professional skills
necessary for preparing the reports are
the same skill level required by small
systems for current reporting and
monitoring requirements.
The classes of small entities that are
subject to the proposed radon rule
include public groundwater systems
serving less than 10,000 people. Small
systems are further classified into very
very small systems (serving 25-500
persons), very small systems (serving
501-3,300 persons, and small systems
(serving 3,301-10,000 persons).
6. Significant Regulatory Alternatives
and SBAR Panel Recommendations
In response to the SBAR Panel's
recommendations and other small entity
concerns, EPA has included several
requirements to help reduce the impacts
of the proposed radon rule on small
entities. These requirements include: (1)
Recommendation of small system
compliance with the MMM/AMCL
option; (2) less routine monitoring; (3)
State granting of waivers to ground
water systems to reduce monitoring
frequency; and (4) encouraging and
providing information about the use of
low maintenance treatment
technologies. A more complete
discussion of the SBAR Panel
recommendations and EPA's responses
follow here. EPA also believes small
systems can in some cases reduce their
economic burden by a variety of means,
including using the State revolving fund
loans to offset compliance costs. In the
development of this proposed
rulemaking, EPA considered several
regulatory alternatives to the proposed
requirements for small systems. The
proposal includes the regulatory
expectation that they comply with the
AMCL of 4,000 pCi/L and be associated
with either a state or local MM program.
EPA believes that this option will
provide equivalent or greater health
protection while reducing economic
burdens to small systems. For a more
detailed description of the alternatives
considered in the development of the
proposed rule see the RIA (USEPA
1999f) or the discussion of regulatory
alternatives in Section XIV.C (Unfunded
Mandates Reform Act).
In addition to being summarized here,
the public docket for this proposed
rulemaking includes the SBAR Panel's
report on the proposed radon regulation,
which outlines background information
on the proposed radon rule and the
types of small entities that may be
subject to the proposed rule; a summary
of EPA's outreach activities; and the
comments and recommendations of the
small entity representatives (SERs) and
the Panel.
(a) Consultations. Consistent with the
requirements of the RFA as amended by
SBREFA, EPA has conducted outreach
directly to representatives of small
entities that may be affected by the
proposed rule. Anticipating the need to
convene a SBAR Panel under Section
609 of the RFA/SBREFA, in
consultation with the Small Business
Administration (SBA), EPA identified
23 representatives of small entities that
were most likely to be subject to the
proposal. In April, 1998, EPA prepared
an outreach document on the radon rule
titled "Information for Small Entity
Representatives Regarding the Radon in
Drinking Water Rule" (USEPA 1998b).
EPA distributed this document to the
small entity representatives (SERs), as
well as stakeholder meeting discussion
documents and the executive summary
of the February 1994 document "Report
to the United States Congress on Radon
in Drinking Water: Multimedia Risk and
Cost Assessment of Radon" (EPA
1994a).
On May 11, 1998, EPA held a small
entity conference call from Washington
DC to provide a forum for small entity
input on key issues related to the
planned proposal of the radon in
drinking water rule. These issues
included: (1) Issues related to the rule
development, such as radon health
risks, occurrence of radon in drinking
water, treatment technologies, analytical
methods, and monitoring; and (2) issues
related to the development and
implementation of the multimedia
mitigation program guidelines. Thirty
people participated in the conference
call, including 13 SERs from small
water systems from Arizona, California,
Nebraska, New Hampshire, Utah,
Washington, Alabama, Michigan,
Wyoming, and New Jersey.
Efforts to identify and incorporate
small entity concerns into this
rulemaking culminated with the
convening of a SBAR Panel on July 9,
1998, pursuant to Section 609 of RFA/
SBREFA. The four person Panel was
headed by EPA's Small Business
Advocacy Chairperson and included the
Director of the Standards and Risk
Management Division within EPA's
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Office of Ground Water and Drinking
Water, the Administrator of the Office of
Information and Regulatory Affairs with
the Office of Management-and Budget,
and the Chief Counsel for Advocacy of
the SBA. For a 60-day period starting on
the convening date, the Panel reviewed
technical background information
related to this rulemaking, reviewed
comments provided by the SERs, and
met on several occasions. The Panel also
conducted its own outreach to the SERs
and held a conference call on August
10, 1998 with the SERs to identify
Issues and explore alternative
approaches for accomplishing
environmental protection goals while
minimizing impacts to small entities.
Details of the Panel process, along with
summaries of the conference calls with
the SERs and the Panel's findings and
recommendations, are presented in the
September 1998 document "Final
Report of the SBREFA Small Business
Advocacy Review Panel on EPA's
Planned Proposed Rule for National
Primary Drinking Regulation: Radon"
(USEPA 1998c).
(b) Recommendations and Actions.—
Today's notice incorporates all of the
recommendations on which the Panel
reached consensus. In particular, the
Panel made a number of
recommendations regarding the MMM
program guidelines, including that the
guidelines be user-friendly and flexible
and provide a viable and realistic
alternative to meeting the MCL, for both
States and CWSs. The Panel also agreed
that provision of information to the
public and equity are important
considerations in the design of an MMM
program.
In response to the Panel's
recommendations and concerns heard
from other stakeholders, EPA has
developed specific criteria that MMM
programs must meet to be approved by
EPA. EPA believes these criteria are
simple and straightforward and provide
the flexibility States and public water
systems need to develop programs to
meet their different needs and concerns.
The criteria permit States, with public
participation and input, to determine
their own prospective indoor radon risk
reduction goals and to design the
program strategies they determine are
needed to achieve these goals. The
criteria build on the existing framework
of State indoor radon programs that are
already working to get indoor radon risk
reduction. EPA also believes that equity
issues can be most effectively discussed
and resolved with the public's
participation and involvement in
development of goals and strategies for
an MMM program. Providing customers
of public water systems with
information about the health risks of
radon and on the AMCL and MMM
program option will help to promote
understanding of the significant public
health risks from radon in indoor air
and help the public to make informed
choices. Section VI of this Preamble
discusses the MMM program in greater
detail.
Following is a summary of the other
Panel recommendations and EPA's
response to these recommendations, by
subject area:
Occurrence: The Panel recommended
that EPA continue to refine its estimates
of the number of affected wells. The
occurrence section of the preamble
contains an expanded description in
regard to how EPA refined the estimates
of the number of affected water supply
wells (See Section XI.C "EPA's Most
Recent Studies of Radon Levels in
Ground Water").
Water Treatment: The Panel
recommended the following: provide
clear guidance for when granular
activated carbon (GAC) treatment may
be appropriate as a central or point-of-
entry unit treatment technology;
consider and include in its regulatory
cost estimates, to the extent possible,
the complete burden and benefits; and
carefully consider effects of radon-off-
gassing from aeration towers and
potential permitting requirements in
developing regulations or guidance
related to aeration.
In response to these
recommendations, the treatment section
of the preamble contains an expanded
description regarding conditions under
which granular activated carbon (GAC)
treatment may be appropriate as a
central or point-of-entry unit treatment
technology (See Section VIII.A.3
"Centralized GAC and Point-of-entry
GAC"); the RIA and the treatment
sections of the preamble describe the
components which contribute to the
regulatory economic analysis (See
Section VTII.A.2 "Treatment Costs: BAT,
Small Systems Compliance
Technologies, and Other Treatment");
high-end treatment cost estimates have
been revised to include scenarios where
air-permitting costs are much higher
than typical cases (see Sections VIII.A. 2
"Treatment Cost Assumptions and
Methodology" and "Comparison of
Modeled Costs with Real Costs from
Case Studies"); and information and
rationale has been added to support
EPA's belief that permitting
requirements from off-gassing from
aeration towers will not preclude
installation of aeration treatment (see
Section VIII.A.3 "Evaluation of Radon
Off-Gas Emissions Risks").
In addition, the Panel recommended
that EPA fully consider the relationship
of the Radon in Drinking Water Rule
with other rules affecting the same small
entities. In response, the treatment
section of the preamble, the Treatment
and Cost Document, and the RIA have
been expanded to discuss the
relationship of treatment for radon with
other drinking water rules including the
Ground Water Rule, Lead and Copper
Rule, and the Disinfection By-Products
Rules (see Section VIII.A.2 "Potential
Interactions Between the Radon Rule
and Upcoming and Existing Rules
Affecting Ground Water Systems").
Analytical Methods and Monitoring:
The Panel recommended the following:
fully consider the availability and
capacity of certified laboratories for
radon analysis and consider the costs of
monitoring; consider applying the VOCs
sampling method to radon to reduce the
need for additional training; reduce the
frequency of monitoring after initial
determination of compliance and
consider providing waivers from
monitoring requirements when a system
is not at risk of exceeding the MCL; and
develop monitoring requirements that
are simple and easy to interpret to
facilitate compliance by small systems.
In response, the analytical methods
section of the preamble includes
discussion of the availability and
capacity of certified laboratories for
radon analysis (see Section VIII.C
"Laboratory Capacity—Practical
Availability of the Methods"); and a
clarification that the radon sampling
method is the same as for the volatile
organic carbons sampling method (see
Section VIII.B.2 "Sampling Collection,
Handling and Preservation"). The RIA
and the preamble include more detailed
discussion of regulatory costs estimates
including the monitoring costs
estimated (see Section VIII.B.2 "Cost of
Performing Analysis"). The monitoring
section proposed rule provides for a
reduced monitoring frequency to once
every three years if the average of four
quarterly samples is less than 1/2 MCL/
AMCL, provided that no sample exceeds
the MCL/AMCL (see Section VIII.E.4
"Increased/decreased monitoring
requirements" and Section 141.28(b) of
the proposed rule). Section VIII.E.5
"Grandfathering of Data" and Section
141.28(b) of the proposed rule describes
the allowance of grandfathered data, i.e.,
data collected after proposal of the rule,
that meet specified requirements.
Section VIII.E.4 "Increased/decreased
monitoring requirements" of this
Preamble discusses the allowance for
States to grant waivers to ground water
systems to reduce the frequency of
monitoring, i.e., up to a 9 year
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frequency. Section VIII.E, Table VIII.E.l
of this Preamble also describes
monitoring requirements to facilitate
interpretation of the requirements.
General: The Panel recommended that
EPA explore options for providing
technical assistance to small entities to
clearly communicate the risks from
radon in drinking water and indoor air,
the rationale supporting the regulation,
and actions consumers can take to
reduce their risks. Therefore, this
Preamble has been written to clarify to
the public the risks from radon in
drinking water and radon in indoor air,
and the rationale supporting the
proposed regulation (see Sections I
through V of this Preamble).
Areas in which Panel did not reach
consensus: There were also a number of
issues discussed by the Panel on which
consensus was not reached. These
included the appropriateness of the
Agency's affordability criteria for
determining if affordable small system
compliance technologies are available,
the appropriate level at which to set the
MCL, whether EPA should provide a
"model" MMM program for use by
small systems in states that do not adopt
state-wide MMM programs, and
whether information on the risks of
radon and options for reducing it
provides "health risk reduction
benefits" (as referenced in the SDWA)
independent of whether homes are
actually mitigated or built radon
resistant. A detailed discussion of these
issues is included in the Panel report.
EPA is requesting comment on some of
these issues in other parts of the
preamble. To read the full discussion of
the issues on which EPA is requesting
comment, see Sections VILA
"Requirements for Small Systems
Serving 10,000 People or Less", VII.D
"Background on Selection of MCL and
AMCL", and VI.F "Local CWS MMM
Programs in Non-MMM States and State
Role in Approval of CWS MMM
Program Plans."
C. Unfunded Mandates Reform Act
(UMRA)
Title II of the Unfunded Mandates
Reform Act of 1995 (UMRA), P.L. 104-
4, establishes requirements for Federal
agencies to assess the effects of their
regulatory actions on State, local, and
tribal governments and the private
sector. Under UMRA Section 202, EPA
generally must prepare a written
statement, including a cost-benefit
analysis, for proposed and final rules
with "Federal mandates" that may
result in expenditures to State, local,
and tribal governments, in the aggregate,
or to the private sector, of $ 100 million
or more in any one year. Before
promulgating an EPA rule, for wfiieh a
written statement is needed, Section 205
of the UMRA generally requires EPA to
identify and consider a reasonable
number of regulatory alternatives and
adopt the least costly, most cost-
effective or least burdensome alternative
that achieves the objectives of the rule.
The provisions of Section 205 do not
apply when they are inconsistent with
applicable law. Moreover, Section 205
allows EPA to adopt an alternative other
than the least costly, most cost-effective
or least burdensome alternative if the
Administrator publishes with the final
rule an explanation on why that
alternative was not adopted.
Before EPA establishes any regulatory
requirements that may significantly or
uniquely affect small governments,
including tribal governments, it must
have developed, under Section 203 of
the UMRA, a small government agency
plan. The plan must provide for
notification to potentially affected small
governments, enabling officials of
affected small governments to have
meaningful and timely input in the
development of EPA regulatory
proposals with significant Federal
intergovernmental mandates and
informing, educating, and advising
small governments on compliance with
the regulatory requirements.
1. Summary of UMRA Requirements
EPA has determined that this rule
contains a Federal mandate that may
result in expenditures of $100 million or
more for State, local, and tribal
governments, in the aggregate, or the
private sector in any one year.
Accordingly, EPA has prepared, under
Section 202 of the UMRA, a written
statement addressing the following
areas: (1) Authorizing legislation; (2)
cost-benefit analysis including an
analysis of the extent to which the costs
to State, local, and tribal governments
will be paid for by the Federal
government; (3) estimates of future
compliance costs; (4) macro-economic
effects; and (5) a summary of EPA's
consultation with State, local, and tribal
governments, a summary of their
concerns, and a summary of EPA's
evaluation of their concerns. A
summary of this analysis follows and a
more detailed description is presented
in EPA's Regulatory Impact Analysis
(RIA) of the Radon Rule (USEPA 1999f)
which is included in the docket for this
proposed rulemaking.
(a) Authorizing legislation. Today's
proposed rule is proposed pursuant to
Section 1412(b)(13) of the 1996
amendments to the SDWA which
requires EPA to propose and promulgate
a national primary drinking water
regulation for radon, establishes a
statutory deadline of August 1999 to
propose this rule, and establishes a
statutory deadline of August 2000 to
promulgate this rule.
(b) Cost-benefit analysis. Section
XIII.B of this preamble, describing the
Regulatory Impact Analysis (RIA) and
Revised Health Risk Reduction and Cost
Analysis (HRRCA) for radon, contains a
detailed cost-benefit analysis in support
of the radon rule. Today's proposed rule
is expected to have a total annualized
cost of approximately $ 121 million with
a range of potential impacts from $60.4
to $407.6 million, depending on how
many States and local PWSs adopt
MMM programs and comply with the
AMCL. This total annualized cost
consists of total annual impacts on
State, local, and tribal governments, in
aggregate, of approximately $53.5
million and total annual impacts on
private entities of approximately $67.6
million (Note: these estimates are based
on Scenario A which assumes 50
percent of States implement MMM
programs with the remaining 50 percent
of States implementing system-level
MMM programs or complying with the
MCL. Under Scenario E, total costs are
approximately $60.4 million. Total
national costs of full compliance with
an MCL are approximately $407.6
million. Detailed descriptions of the
national costs and MMM scenarios are
shown in Section XIII of this preamble
and Sections 9 and 10 of the RIA
(USEPA 1999f).
The RIA includes both qualitative and
monetized benefits for improvements in
health and safety. EPA estimates the
proposed radon rule will have annual
monetized benefits of approximately
$ 17.0 million if the MCL were to be set
at 4,000 pCi/L and $362 million if set at
300 pCi/L. The monetized health
benefits of reducing radon exposures in
drinking water are attributable to the
reduced incidence of fatal and non-fatal
cancers, primarily of the lung and
stomach. Under baseline assumptions
(no control of radon exposure), 168 fatal
cancers and 9.7 non-fatal cancers per
year are associated with radon
exposures through CWSs. At a radon
level of 4,000 pCi/L, an estimated 2.9
fatal cancers and 0.2 non-fatal cancers
per year are prevented. At a level 300
pCi/L, 62.0 fatal and 3.6 non-fatal
cancers per year are prevented. The
Agency believes that compliance with
an AMCL of 4,000 pCi/L and
implementation of a MMM program
would result in health benefits equal to
or greater than those achieved by
complying with the proposed MCL (300
pCi/L).
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In addition to quantifiable benefits,
EPA has identified several potential
non-quantifiable benefits associated
with reducing radon exposures in
drinking water. These potential benefits
are difficult to quantify because of the
uncertainty surrounding their
estimation. Non-quantifiable benefits
may include any peace-of-mind benefits
specific to reduction of radon risks that
may not be adequately captured in the
Value of Statistical Life (VSL) estimate.
In addition, if chlorination is added to
the process of treating radon via
aeration, arsenic pre-oxidization will be
facilitated. Neither chlorination nor
aeration will remove arsenic, but
chlorination will facilitate conversion of
Arsenic (III) to Arsenic (V). Arsenic (V)
is a less soluble form that can be better
removed by arsenic removal
technologies. In terms of reducing radon
exposures in indoor air, provision of
Information to households on the risks
of radon in indoor air and the
availability of options to reduce
exposure may be a non-quantifiable
benefit that can be attributed to some
components of a MMM program.
Providing such information might allow
households to make more informed
choices about the need for risk
reduction given their specific
circumstances and concerns than they
would have in the absence of a MMM
program.
(!) State and Local Administrative
Costs. States will incur a range of
administrative costs with the MCL and
MMM/AMCL options in complying
with the radon rule. Administrative
costs associated with water mitigation
can include costs associated with
program management, inspections, and
enforcement activities. EPA estimates
the total annual costs of administrative
activities for compliance with the MCL
to be approximately $2.5 million.
Additional administrative costs will
be incurred by those States who comply
with the AMCL and develop an MMM
program plan. In this case, States will
need to satisfy the four criteria for an
acceptable MMM program which
include: (1) Involve the public in
developing the MMM program plan; (2)
set quantitative State-wide goals for
reducing radon levels in indoor air; (3)
submit and implement plans on existing
and new homes; and (4) develop and
implement plans for tracking and
reporting results. The administrative
costs will consist of the various
activities necessary to satisfy these four
criteria. Because EPA is unable to
Specify the number of States that will
implement an MMM program,
administrative costs were estimated
under two assumptions: (1) 50 percent
of States (all water systems in those
States) implement an MMM program;
and (2) 100 percenrof States implement
an MMM program, since we expect that
most States will choose this option.
If a State does not develop an MMM
program plan, any local water system
may chose to meet the AMCL and
prepare an MMM program plan for State
approval. Administrative costs to the
State would consist primarily of
reviewing local program plans and
overseeing compliance. However, local
water systems would bear
administrative costs that resemble the
State costs to administer an MMM
program. To estimate costs for local
water systems in these States, EPA
assumed that all local systems that
exceeded 300 pCi/L but were less than
4,000 pCi/L would choose to administer
an MMM program rather than achieve
the 300 pCi/L level through water
mitigation. It is assumed that, on
average, water mitigation costs will
exceed MMM program administrative
costs for local water systems.
EPA estimates that total annual costs
of approximately $13.2 million are
expected if half the States elect to
administer an MMM program and all
local water systems in the remaining
States undertake MMM programs. In
this case, costs to 50 percent of the
States to administer the MMM program
($2.9 million), and costs to 50 percent
of the States to approve MMM programs
developed by local water systems ($7.8
million) are added to water mitigation
costs ($2.5 million). In this latter case
there would also be costs to local water
systems of $45 million to develop and
implement local MMM programs. This
is the total cost per year across all
system sizes to develop and implement
system-level MMM programs and
assumes approximately 45 percent of
CWSs will do a system-level MMM
plan. The total costs across all system
sizes under Scenario E for system-level
MMM programs is approximately $5
million.
Various Federal financial assistance
programs exist to help State, local, and
tribal governments comply with this
rule. To fund development and
implementation of a MMM program,
States have the option of using Public
Water Systems Supervision (PWSS)
Program Assistance Grant funds [SDWA
Section 1443(a)(l)] and Program
Management Set-Aside funds from the
Drinking Water State Revolving Fund
(DWSRF) program. Infrastructure
funding to provide the equipment
needed to ensure compliance is
available from the DWSRF program and
may be available from other Federal
agencies, including the Housing and
Urban Development's Community
Development Block Grant Program or
the Department of Agriculture's Rural
Utilities Service.
EPA provides funding to States that
have a primary enforcement
responsibility for their drinking water
programs through the PWSS grants
program. States may use PWSS grant
funds to establish and administer new
requirements under their primacy
programs, including MMM programs.
PWSS grant funds may be used by a
State to set-up and administer a State
MMM program.
States may also "contract" to other
State agencies to assist in the
development or implementation of their
primacy program, including an MMM
program for radon. However, States may
not use grant funds to contract to
regulated entities (i.e., water systems)
for MMM program implementation.
An additional source of EPA funding
to develop and implement a MMM
program is through the DWSRF
program. The program awards
capitalization grants to States, which in
turn use funds to provide low cost loans
and other types of assistance to eligible
public water systems to assist in
financing the costs of infrastructure
needed to achieve or maintain
compliance with SDWA requirements.
The DWSRF program also allows a State
to set aside a portion of its capitalization
grant to support other activities that
result in protection of public health and
compliance with the SDWA. The State
Program Management set-aside (SDWA
Section 1452(g)(2)) allows a State to
reserve up to ten percent of its DWSRF
allotment to assist in implementation of
the drinking water program. States must
match expenditures under this set-aside
dollar for dollar. DWSRF State Program
Management set-aside funds can be
used to fund activities to develop and
run an MMM program, similar to those
eligible for funding from PWSS grant
funds.
States may also use State Indoor
Radon Grant (SIRG) funds to assist
States in funding their MMM programs.
The Agency has determined that
activities that implement MMM
activities and that meet current SIRG
eligibility requirements can be carried
out with SIRG funds because the goals
of the MMM program reinforce and
enhance the goals, strategies, and
priorities of the existing State indoor
radon programs that rely on funding
through the SIRG program. However,
expenditure of SIRG will not be
permitted to fund strictly water-related
activities, such as testing or monitoring
of water by CWSs.
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(c) Estimates of future compliance
costs. To meet the requirement in
Section 202 of the UMRA, EPA analyzed
future compliance costs and possible
disproportionate budgetary effects of
both the MCL and MMM/AMCL
options. The Agency believes that the
cost estimates, indicated previously and
discussed in more detail in Section
XIII.B of today's preamble accurately
characterize future compliance costs of
the proposed rule.
(d) Macroeconomic effects. As
required under UMRA Section 202, EPA
is required to estimate the potential
macro-economic effects of the
regulation. These types of effects
include those on productivity, economic
growth, full employment, creation of
productive jobs, and international
competitiveness. Macro-economic
effects tend to be measurable in
nationwide econometric models only if
the economic impact of the regulation
reaches 0.25 percent to 0.5 percent of
Gross Domestic Product (GDP). In 1998,
real GDP was $7,552 billion so a rule
would have to cost at least $18 billion
annually to have a measurable effect. A
regulation with a smaller aggregate
effect is unlikely to have any
measurable impact unless it is highly
focused on a particular geographic
region or economic sector. The macro-
economic effects on the national
economy from the radon rule should be
negligible based on the fact that,
assuming full compliance with an MCL,
the total annual costs are approximately
$43.1 million at the 4,000 pCi/L level
and about $407.6 million at the 300 pCi/
L level (at a 7 percent discount rate) and
the costs are not expected to be highly
focused on a particular geographic
region or industry sector.
(e) Summary of EPA's consultation
with State, local, and tribal governments
and their concerns. Consistent with the
intergovernmental consultation
provisions of section 204 of the UMRA
and Executive Order 12875 "Enhancing
Intergovernmental Partnership," EPA
has already initiated consultations with
the governmental entities affected by
this rule. EPA initiated consultations
with governmental entities and the
private sector affected by this
rulemaking through various means. This
included four stakeholder meetings, and
presentations at meetings of the
American Water Works Association, the
Association of State Drinking Water
Administrators, the Association of State
and Territorial Health Officials, and the
Conference of Radiation Control
Program Directors. Participants in EPA's
stakeholder meetings also included
representatives from National Rural
Water Association, National Association
of Water Companies, Association of
Metropolitan Water Agencies, State
department of environmental protection
representatives, State health department
representatives, State water utility
representatives, the Inter Tribal Council
of Arizona, and representatives of other
tribes. EPA also made presentations at
tribal meetings in Nevada, Alaska, and
California. To address the proposed
rule's impact on small entities, the
Agency convened a Small Business
Advocacy Review Panel in accordance
with the Regulatory Flexibility Act
(RFA) as amended by the Small
Business Regulatory Enforcement
Fairness Act (SBREFA). EPA also held
two series of three conference calls with
representatives of State drinking water
and State radon programs. In addition to
these consultations, EPA made
presentations on the proposed Radon
Rule to the Association of California
Water Agencies, the National
Association of Towns and Townships,
the National League of Cities, and the
National Association of Counties.
Several State drinking water
representatives also participated in
AWWA's Technical Workgroup for
Radon.
The Agency also notified
governmental entities and the private
sector of opportunities to provide input
on the Health Risk Reduction and Cost
Analysis (HRRCA) for radon in drinking
water in the Federal Register on
February 26, 1999 (64 FR 9559). The
HRRCA was published six months in
advance of this proposal and illustrated
preliminary cost and benefit estimates
for various MCL options under
consideration for the proposed rule. The
comment period on the HRRCA ended
on April 12, 1999, and EPA received
approximately 26 written comments. Of
the 26 comments received concerning
the HRRCA, 42 percent were from States
and 4 percent were from local
governments.
The public docket for this proposed
rulemaking contains meeting summaries
for EPA's four stakeholder.meetings on
radon in drinking water, all comments
received by the Agency, and provides
details about the nature of State, local,
and tribal governments' concerns. A
summary of State, local, and tribal
government concerns on this proposed
rulemaking is provided in the following
section.
In order to inform and involve tribal
governments in the rulemaking process,
EPA staff attended the 16th Annual
Consumer Conference of the National
Indian Health Board on October 6-8,
1998, in Anchorage, Alaska. Over nine
hundred persons representing Tribes
from across the country were in
attendance. During the conference, EPA
conducted two workshops for meeting
participants. The objectives of the
workshops were to present an overview
of EPA's drinking water program, solicit
comments on key issues of potential
interest in upcoming drinking water
regulations, and to solicit advice in
identifying an effective consultative
process with tribes for the future.
EPA, in conjunction with the Inter
Tribal Council of Arizona (ITCA), also
convened a tribal consultation meeting
on February 24-25, 1999, in Las Vegas,
Nevada to discuss ways to involve tribal
representatives, both tribal council
members and tribal water utility
operators, in the stakeholder process.
Approximately twenty-five
representatives from a diverse group of
tribes attended the two-day meeting.
Meeting participants included
representatives from the following
tribes: Cherokee Nation, Nezperce Tribe,
Jicarilla Apache Tribe, Blackfeet Tribe,
Seminole Tribe of Florida, Hopi Tribe,
Cheyenne River Sioux Tribe,
Menominee Indian Tribe, Tulalip
Tribes, Mississippi Band of Choctaw
Indians, Narragansett Indian Tribe, and
Yakama Nation.
The major meeting objectives were to:
(1) Identify key issues of concern to
tribal representatives; (2) solicit input
on issues concerning current OGWDW
regulatory efforts; (3) solicit input and
information that should be included in
support of future drinking water
regulations; and (4) provide an effective
format for tribal involvement in EPA's
regulatory development process. EPA
staff also provided a brief overview on
the forthcoming radon rule at the
meeting. The presentation included the
health concerns associated with radon,
EPA's current position on radon in
drinking water, the distinction between
an MCL and AMCL, the multimedia
mitigation (MMM) program, and
specific issues for tribes. The following
questions were posed to the tribal
representatives to begin discussion on
radon in drinking water: (1) Will tribal
governments be interested in
substituting MMM for drinking water
control; (2) what types of MMM could
tribes reasonably implement; and (3)
what resources are available to fund
MMM? The summary for the February
24-25, 1999, meeting was sent to all 565
Federally recognized tribes in the
United States.
EPA also conducted a series of
workshops at the Annual Conference of
the National Tribal Environmental
Council which was held on May 18-20,
1999, in Eureka, California.
Representatives from over 50 tribes
attended all, or part, of these sessions.
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59351
The objectives of the workshops were to
provide an overview of forthcoming
EPA regulations affecting water systems;
discuss changes to operator certification
requirements; discuss funding for tribal
water systems; and to discuss
Innovative approaches to regulatory cost
reduction. Tribal representatives were
generally supportive of regulations
which would ensure a high level of
water quality, but raised concerns over
funding for regulations. With regard to
the forthcoming proposed radon rule.
many tribal representatives saw the
multimedia mitigation option as highly
desirable, but felt that this option may
not be adapted unless funds were made
available for home mitigation. Meeting
summaries for EPA's tribal
consultations are available in the public
docket for this proposed rulemaking.
(f) Nature of state, local, and tribal
government concerns and how EPA
addressed these concerns. State and
local governments raised several
concerns, including the high costs of the
rule to small systems; the high degree of
uncertainty associated with the benefits;
the high costs of including Non-
Transient Non-Community Water
Systems (NTNCWSs); and the inclusion
of risks to both smokers and non-
smokers in the proposed regulation.
Tribal governments raised several
concerns with the MMM program,
including where the funding to mitigate
homes would come from; the number of
homes that would require testing; and
the frequency of home testing.
EPA understands the State, local, and
tribal government concerns with the
Issues described previously. The
Agency believes that the options for
small systems, proposed for public
comment in this rulemaking, will
address stakeholder concerns pertaining
to small systems and will help to reduce
the financial burden to these systems.
Non-Transient Non-Community Water
Systems (NTNCWSs) are not subject to
this proposed rulemaking. A detailed
discussion of the exposure to radon in
NTNCWSs is shown in Section XII.D of
this preamble. EPA has conducted a
preliminary analysis on exposure and
risks to NTNCWSs and is soliciting
public comment on this preliminary
analysis. An analysis of the potential
benefits and costs of radon in drinking
water for NTNCWSs is included in the
docket for this proposed rulemaking.
(USEPA 1999m)
EPA has included the risks to both
ever-smokers and never-smokers in this
proposed rulemaking. The Agency is
basing this regulation on the risks to the
general population and is not excluding
any particular segments of the
population. For a more complete
discussion on the risks of radon in
drinking water and air, see Section XII
of this preamble.
EPA understands tribal governments'
concerns with funding for the MMM
program. To assist State, local, and
tribal governments with the
implementation of an MMM program,
EPA is making available Public Water
Supply Supervision (PWSS) Program
Assistance Grant Funds, Drinking Water
State Revolving Fund (DWSRF) funds,
and State Indoor Air Grant (SIRG) funds.
A more complete discussion of the
funding available to State, local, and
tribal governments for MMM program
implementation is shown in Section
XIV.C.l(b) of this preamble.
(g) Regulatory Alternatives
Considered. As required under Section
205 of the UMRA, EPA considered
several regulatory alternatives in
developing an MCL for radon in
drinking water. In preparation for this
consideration, the Regulatory Impact
Analysis and Health Risk Reduction and
Cost Analysis (HRRCA) for Radon
evaluated radon levels of 100, 300, 500,
700, 1,000, 2,000, and 4,000 pCi/L.
The Regulatory Impact Analysis and
HRRCA also evaluated national costs
and benefits of MMM implementation,
with States choosing to reduce radon
exposure in drinking water through an
Alternative Maximum Contaminant
Level (AMCL) and radon risks in indoor
air through MMM programs. Based on
the National Academy of Sciences
recommendations, the AMCL level that
was evaluated is 4,000 pCi/L. For
further discussion on the regulatory
alternatives considered in this proposed
rulemaking, see Section XIII.B of this
preamble.
EPA believes that the regulatory
approaches proposed in today's notice
are the most cost-effective options for
radon that achieve the objectives of the
rule, including strong public health
protection. For a complete discussion of
this issue, see EPA's Regulatory Impact
Analysis and Revised HRRCA for Radon
(USEPA 1999f).
2. Impacts on Small Governments
In preparation for the proposed radon
rule, EPA conducted analysis on small
government impacts. This rule may
significantly impact small governments.
EPA included small government
officials or their designated
representatives in the rule making
process. EPA conducted four
stakeholder meetings on the
development of the radon rule which
gave a variety of stakeholders, including
small governments, the opportunity for
timely and meaningful participation in
the regulatory development process.
Groups such as the National Association
of Towns and Townships, the National
League of Cities, and the National
Association of Counties participated in
the proposed rulemaking process.
Through such participation and
exchange, EPA notified potentially
affected small governments of
requirements under consideration and
provided officials of affected small
governments with an opportunity to
have meaningful and timely input into
the development of the regulatory
proposal.
EPA also held a conference call on
May 11, 1998, to consult directly with
representatives of small entities that
may be affected by the proposed rule.
This conference call provided a forum
for Small Entity Representative (SER)
input on key issues related to the
proposed radon rule. These issues
included: (1) Issues related to the rule
development, such as radon health
risks, occurrence of radon in drinking
water, treatment technologies, analytical
methods, and monitoring; and (2) issues
related to the development and
implementation of the MMM program
guidelines.
As required by SBREFA, EPA also
convened a Small Business Advocacy
Review (SBAR) Panel to help further
identify and incorporate small entity
concerns into this proposed rulemaking.
For a sixty-day period starting in July
1998, the Panel reviewed technical
background information related to this
rulemaking, reviewed comments
provided by the SERs, and met on
several occasions with EPA and on one
occasion with the SERs to identify
issues and explore alternative
approaches for accomplishing
environmental goals while minimizing
impacts to small entities. The SBAR
final report on the proposed radon rule,
which includes a description of the
SBAR Panel process and the Panel's
findings and recommendations, is
available in the public docket for this
proposed rulemaking. For a more
detailed discussion of the Panel report,
see Section XIV.B of this preamble.
In addition, EPA will educate, inform,
and advise small systems, including
those run by small governments, about
the radon rule requirements. One of the
most important components of this
process is the Small Entity Compliance
Guide, required by the Small Business
Regulatory Enforcement Fairness Act of
1996 after the rule is promulgated. This
plain-English guide will explain what
actions a small entity must take to
comply with the rule. Also, the Agency
is developing fact sheets that concisely
describe various aspects and
requirements of the radon rule.
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D. Paperwork Reduction Act (PRA)
The information collection
requirements in this proposed rule have
been submitted for approval to the
Office of Management and Budget
(OMB) under the Paperwork Reduction
Act, 44 U.S.C. 3501 etseq. An
Information Collection Request (ICR) ,
document has been prepared by EPA
(ICR, No. 1923.01) and a copy may be
obtained from Sandy Farmer by mail at
OP Regulatory Information Division,
U.S. Environmental Protection Agency
(2137), 401 M St., SW, Washington, DC
20460; by email at
farmer.sandy@epa.gov; or by calling
(202) 260-2740. A copy may also be
downloaded off the Internet at http://
www.epa.gov/icr.
Two types of information will be
collected under the proposed radon
rule. First, information on individual
water systems and their radon levels
will enable the States and EPA to
evaluate compliance with the applicable
MCL or AMCL. This information, most
of which consists of monitoring results,
corresponds to information routinely
collected from water systems for other
types of drinking water contaminants.
Radon monitoring and reporting will
initially be required on a quarterly basis
for at least one year, but thereafter the
frequency may be reduced to annually
or once every three years depending on
the level of radon present (see Section
VIII. E). Other existing information and
reporting requirements, such as
Consumer Confidence Reports and
(proposed) public notification
requirements, will be marginally
expanded to encompass radon along
with other contaminants. As is the case
for other contaminants, required
information on system radon levels
must be provided by affected systems
and is not considered to be confidential.
The second type of information
relates to the MMM program, which is
EPA's recommended approach for small
systems under the proposed radon rule.
Information of this type includes MMM
plans prepared by States as well as
MMM plans prepared by community
ground water systems in States that do
not develop a MMM plan. The proposed
rule allows States to prepare MMM
plans regardless of whether they are
primacy States with respect to drinking
water programs. EPA will review the
MMM plans developed by States, and
States will review system-tevel MMM
plans. These reviews will help ensure
that MMM programs are likely to
achieve meaningful reductions in
human health risks from radon
exposure. Acceptable MMM plans will
include a plan for the collection of data
to track the progress of the MMM
program relative to goals established in
the plans (e.g., data on the number or
rate of mitigated homes and the number
or rate of new homes built radon
resistant). EPA will review State-level
MMM programs at least every five years,
and States will review system-level
programs at least every five years.
Information related to MMM programs
(i.e., the MMM plans and tracking data)
is mandatory for States that choose to
implement an EPA-approved MMM
program and enforce the AMCL for
radon rather than the MCL. Similarly,
information related to system-level
MMM programs is required only from
systems that comply with the AMCL
rather than the MCL and are in States
that do not have a MMM program in
place.
EPA believes the information
discussed previously, on compliance
with the MCL or AMCL and on MMM
programs, is essential to achieving the
radon-related health risk reductions
anticipated by EPA under the proposed
rule.
EPA has estimated the burden
associated with the specific record
keeping and reporting requirements of
the proposed rule in an accompanying
Information Collection Request (ICR),
which is available in the public docket
for this proposed rulemaking. Burden
means the total time, effort, or financial
resources expended by persons to
generate, maintain, retain, or disclose or
provide information to or for a Federal
agency. This includes the time needed
to review instructions; develop, acquire,
install, and utilize technology and
systems for the purposes of collecting,
validating, and verifying information,
processing and maintaining
information, and disclosing and
providing information; adjust the
existing ways to comply with any
previously applicable instructions and
requirements; train personnel to be able
to respond to a collection of
information; search data sources;
complete and review the collection of
information; and transmit or otherwise
disclose the information.
EPA has estimated a range of
administrative costs for the proposed
rule. These costs do not include testing
and mitigating water or testing and
mitigating households in the MMM
program. The PRA requires that average
annual cost and labor for administrative
costs be calculated over a three-year
period. These costs are presented next.
However, because the full
implementation of the proposed rule
does not occur until later years, average
annual cost and labor for a 20-year
period are also presented. These 20-year
average annual costs are presented by
scenarios defined by the proportions of
systems that elect to develop system-
level MMM programs and the
proportions of states that elect to
implement state-wide MMM programs.
These scenarios are described in detail
in Section XIII.G and Section 9 of the
RIA (USEPA 1999f). Based on these
analyses, EPA's burden estimates for the
proposed rule, in both costs and hours,
are as follows:
• Administrative costs to community
groundwater systems for mitigation-
related activities are estimated to be
$14.6 million per year ($357 per system)
or 267,625 hours, distributed by system
size as shown in Table XIV.2. All 40,863
community groundwater systems will
bear these costs under all scenarios
evaluated.
• In the first three years of the rule,
there are no administrative costs to
community groundwater systems for
MMM program activities.
TABLE XIV.2.—ADMINISTRATIVE COSTS TO COMMUNITY WATER SYSTEMS ASSOCIATED WITH WATER MITIGATION AND
SYSTEM-LEVEL MMM PROGRAMS (EXCLUDING MMM TESTING AND MITIGATION)
System size (customers served)
WS (25-100)
WS (101-500)
VS (501-3,300)
S (3,301-10,000)
M (10.001-100K)
Administrative
costs of water
mitigation
($ per year)
4 485 485
4 958 735
3 430 387
848 487
491.944
Administrative
costs of sys-
tem-level
MMM pro-
grams
($ per year)
O
o
o
0
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59353
TABLE XIV.2.—ADMINISTRATIVE COSTS TO COMMUNITY WATER SYSTEMS ASSOCIATED WITH WATER MITIGATION AND
SYSTEM-LEVEL MMM PROGRAMS (EXCLUDING MMM TESTING AND MITIGATION)—Continued
System size (customers served)
L(>100K)
Total For All Systems
Administrative
costs of water
mitigation
($ per year)
23,579
14,598,617
Administrative
costs of sys-
tem-level
MMM pro-
grams
($ per year)
0
0
• State administrative costs
associated with state-wide MMM
programs are estimated up to $6,300 per
year and up to 140 hours per year for
the first three years of the rule.
• State administrative costs to review
system-level MMM programs and
related activities are estimated up to
$5,900 per year and up to 123 hours per
year for the first three years of the rule.
• The total State administrative costs
(water mitigation, state-wide, and
system-level MMM programs) are
estimated up to approximately $3
million per year and 119,887 hours per
year.
Because much of the activity required
under the proposed rule occurs in later
years, this analysis presents average
administrative costs borne by systems
and states over a 20 year period. Again,
these costs do not include water testing
and mitigation or testing and mitigating
households in MMM programs. In
addition, these costs are presented by
scenarios that are defined by the
proportions of systems that elect to
develop system-level MMM programs
and the proportions of states that elect
to implement state-wide MMM
programs.
• Administrative costs to community
groundwater systems for mitigation-
related activities are estimated to be
TABLE XIV.4.—ADMINISTRATIVE COSTS TO COMMUNITY WATER SYSTEMS ASSOCIATED WITH WATER MITIGATION AND
SYSTEM-LEVEL MMM PROGRAMS
[Excluding MMM Testing and Mitigation]
• Administrative costs to States for
water mitigation-related activities are to
be approximately $3 million per year
(Table XIV.3) and 119.625 hours, or
approximately $65.400 per year per
state and 2.600 hours per year per state.
Forty-six states bear these costs under
all scenarios.
Table XTV.3 presents the costs if 100
percent of all states were to incur the
specific administrative costs listed.
However, no state will bear 100 percent
of state-wide MMM program costs and
100 percent of system-level MMM
program costs. These costs will be borne
in an inverse relationship; e.g., 95
percent of the states will bear
administrative costs associated with
state-wide MMM programs and 5
percent of states will bear
administrative costs associated with
system-level MMM programs.
TABLE XIV.3.—STATE ADMINISTRATIVE
COSTS FOR WATER MITIGATION AND
MMM PROGRAMS
$8.6 million per year ($211 per system)
or 145,547 hours per year, distributed
by system size as shown in Table XIV.4.
All 40,863 community groundwater
systems will bear these costs under all
scenarios evaluated.
• Under Scenario A, administrative
costs to community groundwater
systems for MMM program activities are
approximately $45.1 million per year
($2,452 per system) or 174,000 hours
per year for the 18,388 systems (45
percent of all community groundwater
systems) that develop and file an MMM
plan. The costs are distributed across
the system size categories as shown in
Table XIV.4. Under Scenario E,
administrative costs to systems are $5.0
million per year or 19,333 hours per
year. The per-system cost is the same as
Scenario A, but only five percent of
systems (2,042) bear these costs.
Water Mitigation
State-Wide MMM Programs
System-Level MMM Programs
Total State Administrative
Costs
($ per year)
3,009,713
6,346
5,909
3,021 ,968
System size (customers served)
WS (25-100)
WS (101-SOO)
VS (501-3300)
SM •wt— m nnrrt
MMO ooi— 10010 '
L(>100K)
Total for All Systems
Administrative
costs of water
mitigation
($ per year)
2,857,190
2,923,970
2,022,764
500,319
290,080
13,904
8,608,226
Administrative
costs of
system-level
MMM pro-
grams under
scenario A
($ per year
14,978,142
15,328,217
10,603,857
2,622,804
1,520,674
72,886
45,126,581
Administrative
costs of
system-level
MMM pro-
grams under
scenario E
($ per year
1,664,238
1,703,135
1,178,206
291,423
168,964
8,097
5,014,065
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• Total administrative costs to community water systems (water mitigation plus MMM programs) range from $11
million per year under Scenario E to $51.2 million under Scenario A or 165,000 hours under Scenario E to 320,000
hours under Scenario A. The costs are distributed across the various system sizes as shown in Table XIV.5.
TABLE XIV.5.—TOTAL ADMINISTRATIVE COSTS WATER MITIGATION AND MMM PROGRAMS TO COMMUNITY GROUNDWATER
SYSTEMS
System size (customers served)
WS (25-100) ;
VVS (101-500)
VS (501-3,300)
S (3,001-10,000)
M (10,001-100,000) ,
L (1 00,000)
Total lor All Systems
Total adminis-
trative costs
under scenario
•A
($ per year)
16 990 791
17387 906
1 1 238 829
3 412 697
1 873 106
256 893
51 160223
Total adminis-
trative costs
under scenario
E
($ per year)
3 676 887
3 762 824
1 813 178
1 nsi Tifi
521 396
1QP m^
1 1 047 707
• Administrative costs to States for water mitigation-related activities are estimated to be approximately $2.5 million
per year (Table XIV.6) or approximately $53,900 per year per state. Total state burden is approximately 100,000 hours
per year. Forty-six states bear these costs under all scenarios.
TABLE XIV.6.—STATE ADMINISTRATIVE COSTS FOR WATER MITIGATION AND MMM PROGRAMS
1 . ' • . - [$ per year]
Water Mitigation
State-Wide MMM Programs
System-Level MMM Programs
Total State Administrative Costs
Scenario A
2 477 299
2 926 691
7 830 995
1 3 234 985
Scenario E
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59355
used to measure radon in drinking
water.
This proposed rulemaking involves
technical standards. EPA proposes to
use Standard Method 7500-Rn. which is
specific for radon 222 (radon) in
drinking water, for both the MCL and
AMCL for radon in drinking water. This
method meets the objectives of the rule
because it accurately and reliably
detects radon in drinking water below
100 pCi/L. Standard Method 7500-Rn
was approved by the Standard Methods
Committee in 1996 and is described in
the "Standard Methods for the
Examination of Water and Wastewater
(19th Edition Supplement)" which was
prepared and published jointly by the
American Public Health Association.
American Water Works Association, and
Water Environment Federation.
Additional information on this method
is shown in Section Vffl.B.2 of today's
preamble.
EPA is also proposing the use of the
American Society for Testing and
Materials (ASTM) Standard Test
Method for Radon in Drinking Water
(designation: D5072-92) for the AMCL
for radon in drinking water. This
method is specific for radon in drinking
water, but has been shown to accurately
and reliably detect radon only at
concentrations above 1.500 pCi/L and
thus is only useful for the AMCL.
ASTM's Standard Test Method for
Radon in Drinking Water was adopted
by ASTM in 1992 and is described in
the Annual Book of ASTM Standards.
Additional information on this method
is shown in Section VIII.B.2 of this
preamble.
As discussed in Section VIII.B
(Analytical Methods) of this preamble,
EPA is in the process of adopting the
Performance-Based Measurement
System (PBMS) to allow greater
flexibility in compliance monitoring for
this proposed rule and for future rules.
For further information on PBMS, see
Section Vffl.D.
EPA welcomes comments on this
aspect of the proposed rulemaking and,
specifically, invites the public to
identify potentially-applicable
voluntary consensus standards and to
explain why such standards should be
used in this regulation.
F. Executive Order 12898:
Environmental Justice
Executive Order 12898 "Federal
Actions To Address EnviroPopulations
and Low-Income Populations," 59 FR
7629 (February 16, 1994) establishes a
Federal policy for incorporating
environmental justice into Federal
agency missions by directing agencies to
identify and address disproportionately
high and adverse human health or
environmental effects of its programs,
policies, and activities on minority and
low-income populations. The Agency
has considered environmental justice
related issues concerning the potential
impacts of this action and has consulted
with minority and low-income
stakeholders by convening a stakeholder
meeting via video conference
specifically to address environmental
justice issues.
As part of EPA's responsibilities to
comply with E.O. 12898, the Agency
held a stakeholder meeting via video
conference on March 12, 1998, to
address various components of pending
drinking water regulations; and how
they may impact sensitive sub-
populations, minority populations, and
low-income populations. Topics
discussed included treatment
techniques, costs and benefits, data
quality, health effects, and the
regulatory process. Participants
included national, State, tribal,
municipal, and individual stakeholders.
EPA conducted the meeting by video
conference call between eleven cities.
This meeting was a continuation of
stakeholder meetings that started in
1995 to obtain input on the Agency's
Drinking Water programs. The major
objectives for the March 12, 1998,
meeting were: (1) Solicit ideas from
Environmental Justice (EJ) stakeholders
on known issues concerning current
drinking water regulatory efforts; (2)
identify key issues of concern to EJ
stakeholders; and (3) receive suggestions
from EJ stakeholders concerning ways to
increase representation of EJ
communities in OGWDW regulatory
efforts. In addition, EPA developed a
plain-English guide specifically for this
meeting to assist stakeholders in
understanding the multiple and
sometimes complex issues surrounding
drinking water regulation. A meeting
summary for the March 12, 1998,
stakeholder meeting is available in the
public docket for this proposed
rulemaking.
Stakeholders have raised concerns
that this action may have a
disproportionate impact on low-income
and minority populations. The rule
framework and in particular, the MMM
program coupled with a 4,000 pCi/L
AMCL, were discussed with EJ
stakeholders at the March 12, 1998,
meeting. Key issues of concern with the
MMM/AMCL approach included: (1)
The potential for an uneven distribution
of benefits across water systems and
society; (2) the cost of air remediation to
apartment dwellers; and (3) the concern
that the approach could provide water
systems and State governments a
"loophole" through which they could
escape the responsibility of providing
appropriate protection from radon
exposures.
The Agency considered equity-related
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. 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
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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.
The proposed requirements include
the following: (1) A description of
processes the State used to provide for
public participation in the development
of its MMM program plan; (2) a
description of the nature and extent of
public participation that occurred,
including a list of groups and
organizations that participated; (3) 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; (4) 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; and (5)
the State must provide notice and
opportunity for public comment on the
plan prior to submitting it to EPA.
The public is invited to comment on
this aspect of the proposed rulemaking
and, specifically, to recommend
additional methods to address EJ
concerns with the MMM/AMCL
approach for treating radon in drinking
water.
G. Executive Order 13045: Protection of
Children From Environmental Health
Risks and Safety Risks
Executive Order 13045, "Protection of
Children from Environmental Health
Risks and Safety Risks," 62 FR 19885
(April 23, 1997) applies to any rule that:
(1) Is determined to be "economically
significant" as defined under E.O.
12866, and (2) concerns an
environmental health or safety risk that
EPA has reason to believe may have a
disproportionate effect on children. If
the regulatory action meets both criteria,
the Agency must evaluate the
environmental health or safety effects of
the planned rule on children, and
explain why the planned regulation is
preferable to other potentially effective
and reasonably feasible alternatives
considered by the Agency.
This proposed rule is not subject to
the Executive Order because the Agency
does not have reason to believe the
environmental health risks or safety
risks addressed by this action present a
disproportionate risk to children. Based
on the risk assessment for radon in
drinking water developed by the NAS,
children were not identified as being
disproportionately impacted by radon.
The Committee on Risk Assessment of
Exposure to Radon in Drinking Water
that conducted the National Research
Council Risk Assessment of Radon in
Drinking Water Study (NAS 1999b)
concluded, except for the lung cancer
risk to smokers, there is insufficient
scientific information to permit
quantitative evaluation of radon risks to
susceptible subpopulations such as
infants, children, pregnant women,
elderly, and seriously ill persons.
The National Academy of Sciences
Committee on the Biological Effects of
Ionizing Radiation (BEIR VI) (NAS
1999a) noted that there is only one
study (tin miners in China) that
provides data on whether risks from
radon progeny are different for children,
adolescents, and adults. Based on this
study, the committee concluded that
there was no clear indication of an effect
of age at exposure, and the committee
made no adjustments in the model for
exposures received at early ages (NAS
1999a). Nonetheless, we evaluated the
environmental health or safety effects of
radon in drinking water on children.
The results of this evaluation are
contained in Section XII of this
preamble. Copies of the documents used
to evaluate the environmental health or
safety effects of radon in drinking water
on children, including the NAS Reports,
have been placed in the public docket
for this proposed rulemaking.
The public is invited to submit or
identify peer-reviewed studies and data,
of which EPA may not be aware, that
assessed results of early life exposure to
radon in drinking water.
H. Executive Orders on Federalism
Under Executive Order 12875,
"Enhancing the Intergovernmental
Partnership," 58 FR 58093 (October 28,
1993) EPA may not issue a regulation
that is not required by statute and that
creates a mandate upon State, local, or
tribal government, unless the Federal
government provides the funds
necessary to pay the direct compliance
costs incurred by those governments, or
EPA consults with those governments. If
EPA complies by consulting, E.O. 12875
requires EPA to provide to the Office of
Management and Budget a description
of the extent of EP A's prior consultation
with representatives of affected State,
local, and tribal governments, the nature
of their concerns, any written
communications from the governments,
and a statement supporting the need to
issue the regulation. In addition, E.O.
12875 requires EPA to develop an
effective process permitting elected
officials and other representatives of
State, local, and tribal governments "to
provide meaningful and timely input in
the development of regulatory proposals
containing significant unfunded
mandates."
EPA has concluded that this rule will
create a mandate on State, local, and
tribal governments and the Federal
government will not provide the funds
necessary to pay the direct costs
incurred by State, local, and tribal
governments in complying with the
mandate. In developing this rule, EPA
consulted with State, local, and tribal
governments to enable them to provide
meaningful and timely input in the
development of this rule.
As described in Section XlV.C.l.e,
EPA held extensive meetings with a
variety of State and local
representatives, who provided
meaningful and timely input in the
development of the proposed rule.
Summaries of the meetings have been
included in the public docket for this
proposed rulemaking. See Sections
XIV.C. 1 .e and XIV.C. 1 .f for summaries
of the extent of EPA's consultation with
State, local, and tribal governments; the
nature of the governments' concerns;
and EPA's position supporting the need
to issue this rule.
On August 4, 1999, President Clinton
issued a new executive order on
federalism, Executive Order 13132 [64
FR 43255 (August 10, 1999)], which will
take effect on November 2, 1999. In the
interim, the current Executive Order
12612 [52 FR 41685 (October 30, 1987)],
on federalism still applies. This rule
will not have a substantial direct effect
on States, on the relationship between
the national government and the States,
or on the distribution of power and
responsibilities among various levels of
government, as specified in Executive
Order 12612. "This proposed rule
establishes a National Primary Drinking
Water Regulation (NPDWR) for the
control of radon. This regulation is
required by section 1412(b)(13) of the
Safe Drinking Water Act, as amended.
EPA conducted extensive discussions
with States and local governments in
developing this proposal, and
significant flexibility is provided in
implementing these regulations."
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59357
/. Executive Order 13084: Consultation
and Coordination With Indian Tribal
Governments
Under Executive Order 13084,
"Consultation and Coordination with
Indian Tribal Governments," 63 FR
27655 (May 19,1998) EPA may not
Issue a regulation that is not required by
statute, that significantly or uniquely
affects the communities of Indian tribal
governments, and that imposes
substantial direct compliance costs on
those communities, unless the Federal
government provides the funds
necessary to pay the direct compliance
costs incurred by the tribal
governments, or EPA consults with
those governments. If EPA complies by
consulting. E.O. 13084 requires EPA to
provide the Office of Management and
Budget, in a separately identified
section of the preamble to the rule, a
description of the extent of EPA's prior
consultation with representatives of
affected tribal governments, a summary
of the nature of their concerns, and a
statement supporting the need to issue
the regulation. In addition, E.O. 13084
requires EPA to develop an effective
process permitting elected officials and
other representatives of Indian tribal
governments "to provide meaningful
and timely input in the development of
regulatory policies on matters that
significantly or uniquely affect their
communities."
EPA has concluded that this rule will
significantly or uniquely affect
communities of Indian tribal
governments. It will impose substantial
direct compliance costs on such
communities, and the Federal
government will not provide the funds
necessary to pay the direct costs
incurred by the tribal governments in
complying with the rule. In developing
this rule, EPA consulted with
representatives of tribal governments
pursuant to both E.O. 12875 and E.O.
13084. Summaries of the meetings have
been included in the public docket for
this proposed rulemaking. EPA's
consultation, the nature of the
governments' concerns, and EPA's
position supporting the need for this
rule are discussed in Section XIV.C.2 of
this preamble.
J. Request for Comments on Use of Plain
Language
Executive Order 12866 and the
President's memorandum of June 1,
1998, require each agency to write all
rules in plain language. We invite your
comments on how to make this
proposed rule easier to understand. For
example:
• Have we organized the material to
suit your needs?
• Are the requirements in the rule
clearly stated?
• Does the rule contain technical
language or jargon that isn't clear?
• Would a different format (grouping
and order of sections, use of headings,
paragraphing) make the rule easier to
understand?
• Would more (but shorter) sections
be better?
• Could we improve clarity by adding
tables, lists, or diagrams?
• What else could we do to make the
rule easier to understand?
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
EPA's Office of Ground Water and
Drinking Water maintains a website on
radon at the following address: http://
www. epa .gov/safewa ten'radon. h tml.
Documents are placed on the website for
public access.
B. Public Meetings
EPA has consulted with a broad range
of stakeholders and technical experts.
Participants in a series of stakeholder
meetings held in 1997 and 1998
included representatives of public water
systems, State drinking water and
indoor air programs, tribal water
utilities and governments,
environmental and public health
groups, and other Federal agencies. EPA
convened an expert panel in Denver in
November, 1997, to review treatment
technology costing approaches. The
panel made a number of
recommendations for modification to
EPA cost estimating protocols that have
been incorporated into the radon cost
estimates. EPA also consulted with a
subgroup of the National Drinking
Water Advisory Council (NOWAC) on
evaluating the benefits of drinking water
regulations. The NDWAC was formed in
accordance with the Federal Advisory
Committee Act (FACA) to assist and
advise EPA. A variety of stakeholders
participated in the NDWAC benefits
working group, including utility
company staff, environmentalists,
health professionals, State water
program staff, a local elected official,
economists, and members of the general
public.
EPA conducted one-day public
meetings in Washington, D.C. on June
26, 1997; in San Francisco, California on
September 2, 1997; and in Boston,
Massachusetts on October 30, 1997, to
discuss its plans for developing a
proposed NPDWR for radon-222. EPA
presented information on issues related
to developing the proposed NPDWR and
solicited stakeholder comments at each
meeting. EPA also held a series of
conference calls in 1998 and 1999 with
State drinking water and indoor air
programs, to discuss issues related to
developing guidelines for multiedia
mitigation programs. EPA also held a
public meeting in Washington, DC. on
March 16, 1999, to discuss the HRRCA
published on February 26, 1999, and the
multimedia mitigation framework.
C. Small Entity Outreach
EPA has conducted outreach directly
to representatives of small entities that
may be affected by the proposed rule, as
part of SBREFA. A full discussion of the
small entity outreach is in Section
XIV.B.6 "Significant Regulatory
Alternatives and SBAR Panel
Recommendations."
D. Environmental Justice Initiatives
In order to uphold Executive Order
12898, "Federal Actions to Address
Environmental Justice in Minority
Populations and Low-Income
Populations," EPA's Office of Ground
Water and Drinking Water convened a
public meeting in Washington, DC in
March 1998 to discuss ways to involve
minority, low-income, and other
sensitive subgroups in the stakeholder
process and to obtain input on the
proposed radon rule. The meeting was
held in a video-conference format
linking EPA Regions I through IX to
involve as many stakeholders as
possible. EPA has taken the concerns
and issues raised by the environmental
justice community into account while
setting the MCL, MCLG, and AMCL for
radon. For more information on the
March 1998 environmental justice
meeting, and on EPA proposals to
address concerns of stakeholders, see
Section XIV.F of this Preamble.
E. AWWA Radon Technical Work Group
The American Water Works
Association (AWWA) convened a
"Radon Technical Work Group," in
1998 that provided technical input on
EPA's update of technical analyses
(occurrence, analytical methods, and
treatment technology), and discussed
conceptual issues related to developing
guidelines for multimedia mitigation
programs. Members of the Radon
Technical Work Group included
representatives from State drinking
water and indoor air programs, public
water systems, drinking water testing
laboratories, environmental groups and
the U.S. Geological Survey.
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Background
XVI. How Does EPA Develop
Regulations to Protect Drinking Water?
A. Setting Maximum Contaminant Level
Goal and Maximum Contaminant Level
EPA sets an MCLG and MCL or
treatment technology for each regulated
contaminant. The MCLG is based on
analysis of health effects of the
contaminant. Based on the
carcinogenicity of ionizing radiation,
and the NAS' current recommendation
for a linear, non-threshold relationship
between exposure to radon and cancer
in humans (NAS 1999a), the Agency is
proposing an MCLG of zero for radon in
drinking water.
A drinking water MCL applies to
finished (treated) drinking water as
supplied to customers. The SDWA
generally requires that EPA set the MCL
for each contaminant as close as feasible
to the corresponding MCLG, based on
available technology and taking costs
into account. For example,* if the
analytical methods will only allow a
relatively confident measure of a
contaminant at a certain level, then the
MCL cannot practically be set below
that level. In addition, the cost of water
treatment technologies is considered. If
treatment capabilities are limited then
the MCL must be set at a level that is
found to be feasible. The MCL set by
EPA must be protective of public health.
The 1996 amendments to SDWA
require the Administrator to do a cost-
benefit analysis of the MCLs under
consideration and to make a
determination as to whether the benefits
of an MCL under consideration justify
the costs (1412(b)(3)(Q). The
Administrator may set an MCL at a level
less stringent than the feasible level if
he/she finds that the benefits of the
feasible MCL do not justify the costs
(1412(b)(6)(A)). There are certain
exceptions to the use of this authority
(1412(b)(6)(B)and(C)).
B. Identifying Best Available Treatment
Technology
As discussed also in Section VIII of
this preamble, EPA identifies one or
more water treatment technologies (i.e.,
best available treatment (BAT)) found to
be effective in removing the
contaminant from drinking water and
capable of meeting the MCL. There are
a number of physical, chemical, and
other means used by such treatment
technologies for removing the
contaminant, or in some cases
destroying the contaminant or otherwise
changing the contaminant's
composition. In assessing potential
BATs, EPA examines removal
efficiency, cost to purchase and
maintain, compatibility with other
processes, and other factors. Most of the
information cited by EPA in this context
is gleaned from technical literature,
including research studies covering
pilot or full scale treatments. If some of
the treatments identified are found to be
most efficient, practical and economical,
EPA places these on the BAT list and on
occasion may provide guidance on other
treatments that may have certain
limitations.
C. Identifying Affordable Treatment
Technologies for Small Systems
The 1996 Amendments to the SDWA
directed EPA to identify treatment
technologies that are affordable for
small water systems. EPA is charged
with identifying affordable treatments
for three small system population
categories: systems serving from 25 to
500, 501 to 3,300, and 3,301 to 10,000
persons. A designated "compliance
technology" for these small systems
may be a technology that is affordable
and that achieves compliance with the
MCL or a treatment technique
requirement. Possible compliance
technologies may include packaged or
modular systems, and point-of-entry
(POE) or point-of-use (POU) type
treatment units. As with BAT
designations, the compliance
technology(ies) selected by EPA must be
based upon available information from
technical journals and/or qualified
research studies.
EPA must also identify affordable
"variance technologies" which are to be
installed by a public water system after
the system has applied to the
responsible primacy agency for a
variance, i.e., a "small system variance."
This variance applies only to systems
serving fewer than 10,000 people. It also
applies only in cases where an
affordable technology is not available to
achieve compliance with an MCL (or
treatment technique requirement) yet
still will be protective of public health.
One of the requirements for systems that
have obtained a variance is to install
and maintain the variance technology in
accordance with the listing by EPA,
which may be specific to system size
and/or dependent upon source water
quality. A small system variance may
only be obtained if compliance with the
MCL through alternate source,
treatment, or restructuring options are
deemed not to be affordable for that
system.
Small system variances are not
available to meet MCL or treatment
technique requirements promulgated
prior to 1986, nor for regulations
addressing microbiological
contamination of water.
D. Requirements for Monitoring, Quality
Control, and Record Keeping
Water systems are responsible for
conducting monitoring of drinking
water to ensure that it meets all drinking
water standards. To do this, water
systems and States use analytical
methods set out in" EPA regulations.
EPA is responsible for evaluating
analytical methods developed for
drinking water and approves those
methods that it determines meet Agency
requirements. Laboratories analyzing
drinking water compliance samples
must be certified by the EPA or the
State.
Whether addressing regulated or
unregulated contaminants, EPA
establishes requirements as to how often
water systems must monitor for the
presence of the subject contaminant.
Water systems serving larger
populations generally must conduct
more monitoring (temporally and
spatially) because there is a greater
potential human health impact of any
violation, and because of the physical
extent of larger water systems (e.g.,
miles of pipeline carrying water). Small
water systems can receive variances or
exemptions from monitoring in limited
circumstances. In addition, under
certain conditions, a State may have the
option to modify monitoring
requirements on an interim or a
permanent basis for regulated
contaminants, with a few exceptions.
States may use this flexibility to reduce
monitoring requirements for systems
with low risk of incurring a violation.
E. Requirements for Water Systems to
Notify Customers of Test Results if Not
in Compliance
Each owner or operator of a public
water system must notify customers if
the system has failed to comply with an
MCL or treatment technique
requirement, or a testing procedure
required by EPA regulation. A system
must notify its customers if the system
is subject to a variance (due to an
inability to comply with an MCL).
The form of this notification must be
readily understood and delivered via
mail or direct delivery, through an
annual report, or in the first water
billing cycle following such a drinking
water violation. The notification must
also contain important information
about the contaminant so that
consumers will be aware of any
particular hazards involved; the
notification may indicate whether water
can/cannot be consumed or used for
bathing, whether boiling drinking water
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59359
will make it safe: or whether storing
water before use may be advisable.
R Approval of State Drinking Water
Programs to Enforce Federal
Regulations
Sectiorvl413ofthe SD WA sets
requirements that a State or eligible
Indian tribe must meet in order to
maintain primary enforcement
responsibility (primacy) for its public
water systems. These include (1)
adopting drinking water regulations that
are no less stringent than Federal
NPDWRs; (2) adopting and
implementing adequate procedures for
enforcement; (3) keeping records and
making reports available on activities
that EPA requires by regulation; (4)
issuing variances and exemptions (if
allowed by the State) under conditions
no less stringent than allowed by
Sections 1415 and 1416; (5) adopting
and being capable of implementing an
adequate plan for the provision of safe
drinking water under emergency
situations, and (6) adopting authority for
administrative penalties.
In addition to adopting the basic
primacy requirements, States may be
required to adopt special primacy
provisions pertaining to a specific
regulation. These regulation-specific
provisions may be necessary where
Implementation of the NPDWR involves
activities beyond those in the generic
rule. States are required by 40 CFR
142.12 to include these regulation-
specific provisions in an application for
approval of their program revisions.
XVII. Important Technical Terms
Adsorption: In the case of the water/
solid interface, the accumulation of a
dissolved chemical species at the
Interface between a solid material (e.g.,
granular activated carbon) and water.
Alpha particle: A radioactivity decay
product consisting of the charged
helium-4 nucleus (two protons and two
neutrons with a positive ionic charge of
two. +2). Alpha particles are relatively
heavy (8000 times as heavy as the beta
particle) and are quickly absorbed by
surrounding matter. The properties of
alpha particles are such that they are
only a health hazard if the emitter is in
contact with living tissue. When outside
the body, they do not penetrate the skin
and are stopped by a few centimeters of
air. However, when inside the body
(breathed in or ingested), the alpha
particle may ionize molecules within
cells or may form "free radicals" (an
atom or chemical group that contains an
unpaired electron and which is very
chemically reactive), either of which
may result in the disruption of normal
cellular metabolism and produce
changes that affect cell replication
which may induce cancerous cellular
growth.
Bq (becquerel): An alternative unit of
radioactivity is the Bq, which is equal
to 1 disintegration per second. One pCi
is equal to 0.037 Bq, and one Bq is equal
to 27 pCi.
cpm/dpm: Counts per minute divided
by radioactive disintegrations per
minute; counting efficiency as
determined by the counts per minute
detected relative to the predicted
disintegrations per minute in a well-
characterized standard.
Half-life: The time required for one-
half of a population of radioactive
isotopes to decay; in the case of
radioactive contaminants dissolved in
water, it is the time for the
concentration of the radioactive
contaminant to decrease by a factor of
two due to radioactive decay.
Heterotrophic Plate Count: A
laboratory procedure for estimating the
total bacterial count in a water sample
(or "bacterial density").
Individual Risk: The risk to a person
from exposure to radon in water is
calculated by multiplying the
concentration of radon in the water
(pCi/L) by the unit risk factor (risk per
pCi/L) for the exposure pathway of
concern (ingestion, inhalation).
Isotopes: Two or more forms of an
atomic element having the same number
of protons, but differing in the number
of neutrons. Some isotopes are stable
(not radioactive) and some are
radioactive, depending upon the ratio of
neutrons and protons.
Monte Carlo Analysis:: Method of
approximating a distribution of model
solutions by sampling from simulated
"random picks" from distributions of
model input values.
pCi (picocurie):: a unit of radioactivity
equal to 0.037 radioactive
disintegrations per second.
Percentile: For any set of observations,
the "pth percentile value" is the value
such that p% of the observations fall
below the pth percentile value and (100-
p)% fall above it.
pH: Numerical scale for measuring the
relative acidity or basicity of an aqueous
solution; values less than 7 are acidic
(becoming increasingly so as they
decrease) and above 7 are basic
(becoming increasing so as they
increase).
Radioactivity: The spontaneous
disintegration of unstable atomic nuclei
(central core of an atom), resulting in
the formation of new atomic elements
(daughter products), which may or may
not themselves be radioactive, and the
discharge of alpha particles, beta
particles, or photons (other decay
particles are known, but their parent
isotopes do not occur in drinking
water).
Removal efficiency. A measure of the
ability of a particular water treatment
process to remove a contaminant of
interest; defined as the concentration of
the contaminant in the treated water
(effluent) divided by the concentration
of the contaminant in the source water
(influent).
WL (working level): Any combination
of radioactive chemicals that result in
an emission of 1.3 x 10s MeV of alpha
particle energy. One WL is
approximately the total amount of
energy released by the short-lived
progeny in equilibrium with 100 pCi of
radon.
Working Level Month (WLM): 170
hours of exposure to one Working Level
(WL) of radon progeny.
Unit Risk: The risk from lifetime
exposure, via the inhalation and
ingestion exposure routes, to water
containing an unit concentration (1 pCi/
L) of radon.
XVIII. References
American Society for Testing and Materials.
1992 Annual Book of ASTM Standards,
Standard Test Method for Radon in
Drinking Water. Designation: D 5072-92.
Vol. 11.01, Philadelphia, PA. [1992]
[ASTM 1992]
American Water Works Association. Water:/
Stats: The Water Utility Database, 1996
Survey: Water Quality, Denver, CO. [1997]
[AWWA 1997]
American Water Works Association. Existing
Volatile Organic Chemical Treatment
Installations: Design, Operations, and
Costs, Report of the Organic Contaminants
Control Committee. Denver, CO. [1991]
[AWWA 1990]
American Water Works Association Research
Foundation. Assessment of GAC
Absorption for Radon Removal, Denver,
CO. [November 1998] [AWWARF 1998a]
American Water Works Association Research
Foundation. Critical Assessment of Radon
Removal Systems for Drinking Water
Supplies, Denver, CO. [December 1998]
[AWWARF 1998b]
California Department of Health Services.
Letter with Attachment Regarding Radon
Sampling Protocol from Jane Jensen of the
CA DHS Environmental Laboratory
Accreditation Program to William Labiosa,
USEPA, Office of Ground Water and
Drinking Water, [September 3, 1997] [CA
DHS 1997]
Centers for Disease Control. Morbidity and
Mortality Weekly Report, Cigarette
smoking among adults—United States
1993. [1995] [CDC 1995]
Cornwell, D.A. Air Stripping and Aeration. In
Water Quality and Treatment, 4th Edition,
F. Pointius, ed. American Water Works
Association. McGraw-Hill, Inc. New York,
NY. 1990. [Cornwell 1990]
Davis, R.M.S. and Watson, J.E. Jr. The
Influence of Radium Concentration in
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Surrounding Rock on Radon Concentration
in Ground Water, University of North
Carolina, Chapel Hill. [March 13, 1989]
[Davis and Watson 1989]
Dell'Orco M.J., Chadik. P., Bitton, G., and
Neumann, R. Sulfide-Oxidizing Bacteria:
Their Role During Air-Stripping. J. of the
American Water Works Association.
(90:107-115). [October 1998] [Dell'Orco et
al. 1998]
Dihm, H. and Carr, F.R. Air Stripping Tower
Fouling Control for a Groundwater
Treatment System in Florida. In Air
Stripping of Volatile Organic Contaminant
Removal. AWWA. Denver, CO. [1988]
[Dihm and Carr 1988]
Dixon, K. and Lee, R. Radon Survey of the
American Water Works System. In Radon
in Ground Water. Barbara Graves, ed.
Lewis Publishers, Inc. Chelsea, MI. [1987]
[Dixon and Lee 1987]
Dyksen, J.E., Raczko, R.F., and Cline, G.C.
Operating Experiences at VOC Treatment
Facilities. In Proc. of the 1995 AWWA
Annual Conference. Anaheim, CA. [June
1995] [Dyksen etal. 1995]
Ershow, A.G. and Cantor K.P. Total Water
and Tapwater Intake in the United States:
Population-based Estimates of Quantities
and Sources. Report prepared under
National Cancer Institute Order #263-MD-
810264. [1989] [Ershow and Cantor 1989]
Faust, S.D. and Aly, O.M. Chemistry of Water
Treatment. Ann Arbor Press, Inc. Chelsea,
MI. p. 477. [1998] [Faust and Aly 1998]
Federal Register. Vol. 51, No. 189. Water
Pollution Control; National Primary
Drinking Water Regulations:
Radionuclides, Advance Notice of
Proposed Rulemaking (September 30,
1986), 34836-34862. [51 FR 34836]
Federal Register. Vol.56, No. 138. National
Primary Drinking Water Regulations:
Radionuclides, Notice of Proposed
Rulemaking (July 18, 1991) 33050-33127.
[56 FR 33050]
Federal Register. Vol.62, No. 43. National
Primary Drinking Water Regulations:
Analytical Methods for Radionuclides:
Final Rule and Proposed Rule (March 5,
1997) 10168-10175. [62 FR 10168]
Federal Register. Vol 62, No. 60. Guidelines
Establishing Test Procedures for the
Analysis of Pollutants and National
Primary Drinking Water Regulations;
Flexibility in Existing Test Procedures and
Streamlining Proposal of New Test
Procedures: Proposed Rule. (March 28,
1997) 14976—15049. [62 FR 14976]
Federal Register. Vol 62, No. 151.
Withdrawal of the Proposed National
Primary Drinking Water Regulation for
Radon-222: Notice of Withdrawal of
Proposed Rule. (August 6, 1997) 42221-
42222. [62 FR 42221]
Federal Register. Vol 62, No. 193.
Performance Based Measurement System:
Notice of Intent. (October 6, 1997) 52098—
52100. [62 FR 52098]
Federal Register. Vol 63, No. 160. National
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[Wade Miller 1993]
Appendix 1 to the Preamble: What
Were the Major Public Comments on
the 1991 NPRM and How Has EPA
Addressed Them in This Proposal?
EPA received more than 600 comments on
the Notice of Proposed Rulemaking (NPRM)
of July 18, 1991 (56 FR 33050). Of the
comments received, 289 were from public
water suppliers, 89 were from individuals, 76
were from local governments, 52 were from
States, 48 were from companies, 43 were
from trade/professional organizations, 12
were from Federal agencies, 10 were from
health/environmental organizations, 3 were
from Members of Congress, and 2 were from
universities. EPA received additional
comments at public hearings on September 6,
1991, in Washington, DC and on September
12, 1991, in Chicago, Illinois.
Those commenting raised several concerns,
including cost of rule implementation,
especially for small public water systems,
and the larger risk to public health from
radon in indoor air from soil under buildings.
The next sections summarize major public
comments on the 1991 NPRM and provide
brief responses in the following areas of most
concern: (1) General issues; (2) statutory
authority and requirements; (3) radon
occurrence; (4) radon exposure and health
effects; (5) maximum contaminant level; (6)
analytical methods; (7) treatment
technologies and costs; and (8) compliance
monitoring. In many instances the following
sections refer the reader to applicable
sections in today's preamble where many of
the issues have been fully discussed.
A. General Issues
Additional regulation: Some public
comments opposed additional regulation in
general, and additional drinking water
regulation in particular. Some comments also
suggested EPA proceed with a more
integrated approach to environmental
regulation, i.e., that mitigation programs be
designed to provide control over major
exposure routes, which in the case of radon
must take the soil gas source into account.
EPA Response: At the time of the 1991
proposal, EPA did not have authority under
SDWA for a broader radon rule. However, the
SDWA as amended in 1996 provides such
authority. In addition to requiring EPA to
promulgate a regulation for radon in drinking
water, the SDWA radon provision also
includes a less stringent alternative
maximum contaminant level (AMCL) and a
multimedia approach to address radon in
indoor air. Much of the health threat is
associated with radon emanating from soil
gas into indoor air. Risk from drinking water
particularly through the inhalation pathway
is also a significant and preventable risk.
Today's proposal addresses all major routes
of exposure and is intended to promote
multimedia mitigation (MMM) programs and
implementation of the AMCL. Thus, the
Agency expects to provide more cost-
effective reductions-in the health risks
associated with radon.
Federal funding for compliance and
phased implementation: Commenters asked
the Agency for increased flexibility in
complying with the proposed regulation
through phased compliance; cheaper removal
technologies; and/or additional Federal
funding. Industry and other groups also
recommended a phased implementation of
radon removal, focusing first on priority
water sources with the highest radon levels.
EPA Response: Today's proposal provides
different compliance dates for compliance '
with the MCL and with the AMCL/MMM
program, such that there will be sufficient
time to implement the MMM program.
The Agency recognizes that the SDWA
regulations, will continue to place a
significant burden on some small
communities with limited tax bases and
resources with which to attain compliance.
The EPA drinking water State Revolving
Fund provides support to the States and
public and private water suppliers, in
particular to small public water suppliers.
This fund offers capitalization grants to the
States for low-interest loans to help water
systems comply with the SDWA (For more
information refer to Section XIV.C.l of
today's preamble.)
In addition, EPA surveys of public and
private water suppliers have been initiated to
understand more clearly their needs in
particular in terms of funding to support
capital improvements in the context of
implementing SDWA-related plans.
B. Statutory Authority and Requirements
Applicability to non-transient, non-
community (NTNC) systems: Ten
commenters stated that EPA must provide
better justification for regulating non-
transient, non-community water systems
along with community water systems. The :
indoor occupancy factors and exposure rates
are different for persons in the workplace
(i.e., school and hospital) than in the home.
EPA should state clearly how the final rule
will apply to this group.
EPA Response: About one-third of the
systems estimated in 1991 as being affected
by the final regulation were NTNC water
systems. The Agency requested data in 1991
on NTNC system exposure patterns but
received none; subsequently, the Agency
conducted analysis on limited data on NTNC
occurrence and exposure patterns and found
the attendant exposures and risks to be
relatively small in comparison to those
estimated for community water supplies. (For
more information refer to Section XI.D of
today's preamble.)
In keeping with the flexibility accorded the
Agency by SDWA to focus on areas of
cognizable public health risk, EPA proposes
that NTNC water systems not be required to
comply with the proposed radon regulation.
At the same time, EPA is soliciting comment
and data related to this issue and has left
open its options in terms of the final radon
regulation.
State authority: Commenters felt that the
Federal drinking water regulations should
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59363
not be uniform across ^he nation's drinking
water supply. Many drinking water issues,
including those which involve unique
Circumstances in the State and the necessary
resources to implement programs, remain
unresolved and perhaps are not resolvable by
the Federal government. As a result. States
will need to carry more of the responsibility
In regulating drinking water given their
familiarity with local circumstances.
EPA Response: The Agency acknowledges
the unique circumstances faced by State
primacy programs and public water systems.
According to the framework set forth in the
SDWA Amendments, States will have the
option of adopting the MCL or the higher
AMCL and the MMM program to address
radon in indoor air. State programs in this
area are expected to vary, in part due to
radon occurrence patterns locally and in part
due to State resources as they apply to
monitoring public water systems; also States
will have flexibility in MMM program
implementation, and through consideration
of variances and exemptions as allowed
under SWDA.
C. Radon Occurrence
Radon In PWS (Nationwide): The
American Water Works Association (AWWA)
suggested thatEPA's 1991 national
occurrence estimates for radon were low
compared to actual levels, i.e., greater than
20 percent low. resulting in an inaccurate
EPA cost impact estimate. The Association
suggested EPA consider the following
changes to the radon occurrence analysis:
• Disaggregation of the National Inorganics
and Radionuclides Survey (NIRS) occurrence
data for the smallest public systems, i.e.,
those serving fewer than 500 persons, into
two subsets of systems;
• An accounting in the radon occurrence
analysis for geologic conditions in various
regions by applying NIRS data in an area-
specific manner;
• Updating and increasing the inventory
(including NTNCs) based upon FRDS data;
• Inclusion of State radon data in the
national occurrence analysis;
• EPA analyses may have underestimated
radon In water levels because-the location of
sampling in NIRS was in the distribution
systems (where natural decay of radon-222
may have been significant, thereby lowering
occurrence estimates).
EPA Response: EPA analyses of these
Issues addressed the concerns described
previously to the extent feasible (USEP A
1999c). The EPA analyses have Incorporated
the referenced issues as data allowed; the
analyses also addressed newer data collected
and/or submitted to EPA.
The Agency used State radon in drinking
water data to refine the previous analysis that
were based solely on the NIRS data. The
Agency Identified and obtained data from a
number of States that supplement the
geographic coverage, representativeness, and
utility of the NIRS data in predicting the
occurrence of radon in drinking water in the
U.S. Additional data sets were obtained that,
while not addressing radon distributions in
States or regions, provided significant data
related to the sampling, analytical, temporal
and intra-system variability of radon
measurements. The data from the NIRS and
from the supplementary data sources were
subjected to extensive-statisticaLanalysis to
characterize their distribution and compare
data sets.
These analyses are discussed and
referenced in today's preamble Section XI.C.
The results indicate that: radon levels seen in
the NIRS data sets were generally slightly
lower than those seen in the wellhead and
point-of-entry data provided by the same
States (with radon levels being more
comparable in the very small systems due to
short residence times); previous results were
verified that radon levels in the U.S. are the
highest in New England, the Appalachian
uplands and other Western and Midwest
regions; the levels of radon seen in the
supplemental State data sets were similar to
those seen in the NIRS data for the same
regions: and, due to procedures used to
adjust the NIRS data, the proportions of
systems exceeding the various levels in the
current study are greater than those seen in
previous analyses.
However, best estimates of the numbers of
systems exceeding regulatory levels in EPA's
1993 estimate for the 1994 EPA Report to
Congress (USEPA 1994) and the central
tendency estimates in the current analysis are
quite similar. This is because the total
estimated number of community and non-
community non-transient systems that are
believed to be active in the U.S. has
decreased approximately 17 percent between
1993 and the Agency's current estimates. Part
of this difference is due to system
consolidation, and part may be due to
improved methods for differentiating active
from inactive systems, although the relative
importance of these two factors is not known.
Occurrence of radon in California: A
California drinking water industry
association provided a number of resources
including the following: a survey of its
member agencies; a California Department of
Health Services (DHS) Groundwater Study;
and the Metropolitan Water District's (MWD)
Southern California Radon Survey. The
commenter produced estimated radon
occurrence figures which far exceeded EPA's
California and national occurrence profiles.
The commenter's estimate predicted 75
percent to 97 percent of California public
water systems out of compliance with a
radon standard of 300 pCi/L. The commenter
submitted to EPA additional methods and
source data necessary for a complete EPA
evaluation of this comment.
EPA Response: EPA studied the
commenter's methodology for determining
radon occurrence in California, proposed
water system categorization scheme, and the
sources of radon data (surveys mentioned
previously), and has concluded the
following:
• That sampling in the California surveys
biased the results towards higher radon
levels since data were apparently collected at
the wellhead;
• The methods used in combining data
sources (and in substitutions within data
sets) resulted in substantial overestimation of
radon occurrence in California ground water
supplies.
• The commenter assumed 23 percent
more public water supplies in California than
indicated in then-current EPA FRDS records;
• The use of commenter's GIS-predicted
radon levels for California systems was also
problematic (USEPA 1999c).
EPA believes that EPA NIRS survey did not
under represent the levels of radon in
California. A comparison by EPA of the
NIRS-California data and other California
data reveals a similarity in results.
Furthermore, EPA results are more in accord
with California State predictions submitted
to EPA during the same comment period.
Variability of radon levels in water: The
American Water Works Service Company
(AWWSC) provided technical information on
the issue of radon variability in well water.
AWWSC said that the variability of radon
levels in well water is a phenomenon that
could affect the compliance status of systems.
AWWA and the Association of California
Water Agencies also echoed concerns about
the seasonal and diurnal variability in
groundwater.
EPA Response: EPA analyzed this issue to
determine if radon variability may or may not
have any influence on national occurrence
profiles. EPA reviewed the two available
sources of information on radon variability
(Kinner et al. 1990), and data supplied by the
American Water Works Service Co.
(AWWSC). The Kinner report was limited to
four sites in New Hampshire that exhibited
short-term and long-term variability of radon.
The AWWSC data were drawn from 400
wells, nationwide, in 1986 and 1987.
Kinner's data appear to indicate a radon
fluctuation of 20 to 50 percent in well water
over long-term intervals, weekly or biweekly.
The short-term variability (15 to 180 minute
intervals during a three month test at one
site) showed a fluctuation of 50 percent as
observed in the long-term test. These studies
did not try to correlate any of the variability
observed with well yield and water table
level to account for the inconsistent patterns.
The data provided were too limited to
independently analyze factors that may have
influenced radon level fluctuations.
However, EPA notes that the short-term and
long-term variabilities of radon observed at a
single site were similar. This suggests that
the long-term variability may be a reflection
of random sampling where short-term
influences are influencing radon levels.
The AWWSC analysis of radon in well
water included sampling in the fall of 1986
and January 1987. A decrease of 29 percent
on average was found over the two-month
period. A change in analytical procedure
accounted for about 10 percent of that
difference. The remaining 19 percent
difference was not explained. AWWSC also
conducted a test of the effect of pumping
time on radon levels over a short period (five
days then two days), beginning with an idle
period. AWWSC inferred that an observed
initial increase in radon level (about 25
percent) was due to radon decay in water that
had been sitting near the well casing.
According to AWWSC, a subsequent decrease
(much smaller) over two days was due to the
drawing of less enriched water from beyond
a potential geologic radon source yet within
the cone of depression.
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EPA believes that local geologic and
operating conditions may produce temporal
variations in radon levels in ground water
sources. However, data are too limited to
permit drawing of any conclusions. Also,
since the Kinner and AWWSC reports cited
water that generally contained radon in the
high levels, 2,500 to 200,000 pCi/L, and
1,200 to 1,700 pCi/L, respectively, EPA
cannot draw any conclusions on the effect(s)
of short or long-term variability on radon in
water at 300 pCi/L. Because EPA NIRS data
represents single, one-time values for systems
sampled, it produces no basis for a bias
conclusion (i.e., over- or under-estimates).
On the contrary, the random nature of the
NIRS survey would cancel any differences
between the NIRS level and the "true
average" radon level in public supplies.
Radon Emanation from Pipe Scale
Deposits: Data received after the comment
period, and subsequently reviewed by EPA,
suggested that due to an existing radon
source (radium-226) in some systems, levels
of radon-222 may in some instances increase
as water passes through water distribution
systems.
EPA Response: A paper by Valentine et al.
(Valentine 1992) contained data on the
phenomenon of radon levels increasing in
water distribution pipelines. In three of five
distribution systems studied in Iowa, the
paper's authors found what they refer to as
radon "hot spots." These systems have more
radon in delivered water than at the entry to
distribution. However, more geographically
diverse data generally show that natural
radon decay is a more influential factor as
water is distributed. In other words, without
nationally-relevant data to the contrary, it
would be expected that within-distribution
system radon decay supercedes radon
production, except in very specific
circumstances.
A more recent article by Field et al. (1995)
reported that a case study of an Iowa water
system with an average of 2.2 mg/L dissolved
iron and 2.5 pCi/L of radium-226. The
finished water entering the distribution
system had a mean radon level of 432 + 54
pCi/L (one standard deviation). Field et al.
measured radon levels at the taps of 25
homes and measured radon levels ranging
from 81 pCi/L to 2,675 pCi/L, with a mean
of 1,108 ± 648 pCi/L. The authors concluded
that iron scale deposits were sorbing radium-
226, the parent of radon-222. In the case
study reported, greater than 80% of the
surface pipe-scale was comprised by iron
oxides, with traces of scales containing
calcium and silicon. Since iron oxides have
been shown to selectively scavenge radium,
it is plausible that a co-occurrence of high
iron and radium levels may result in the
production of significant levels of radon
within the distribution system. Other factors
that would determine the level of radon
produced include concentration of radium-
226 sbrbed to the pipe scale, the quantity,
distribution, and surface area of the scale, the
composition of the scale, all of which are
determined by the average finished water
quality, and the length of time the water is
in contact with the scale. All case studies
were confined to the state of Iowa.
It remains to be shown that the confluence
of conditions that result in significant radon
production within distribution systems exists
commonly at the national level or is confined
to specific locales (e.g., areas with high
average levels of iron, radium-226, and other
site-specific factors).
Regarding this issue, information available
at the present time does not support a
determination as to the extent to which this
phenomenon may occur in the U.S. The
Agency is, however, soliciting comments in
today's proposal on the advisability of
requiring additional monitoring for radon as
a source of consumer exposure from the
distribution system, and on other radon
occurrence issues.
D. Radon Exposure and Health Effects
Approximately 400 public comments were
submitted on the assessments of exposure to
and health effects of radon in the 1991
NPRM. The major issues raised in these
comments, including comments regarding
the proposed MCLG, are addressed next.
Linear no-threshold dose response model:
Many commenters were concerned that EPA
only used a linear no-threshold dose-
response model in, projecting cancer risk
associated with low level exposure to radon
in the domestic environment.
EPA Response: The shape of the dose-
response curve for radon has been evaluated
in detail by the NAS (1999a, 1999b), who
concluded that essentially all available data
are consistent with a linear non-threshold
mechanism. This includes data on the effects
of a wide range of ionizing radiation, as well
as direct dose-response relationships
observed for radon in animals studies and in
studies of cohorts of underground miners.
The EPA concurs with the NAS evaluation
and conclusion.
Age dependence on risk from radon
exposure: A few commenters stated that EPA
should consider the effect of exposure at
young ages. According to these commenters,
the additional risks in children were not well
addressed.
EPA Response: Data on the relative
sensitivity of children to radon are sparse. In
general, the NAS Radon in Drinking Water
Committee concluded that there is
insufficient scientific information to permit
quantitative evaluation of the risks of lung
cancer death from inhalation exposure to
radon progeny in susceptible sub-
populations such as infants, children,
pregnant women, and elderly and seriously
ill persons. However, the BEIR VI committee
(NAS 1999a) noted that there is one study
(tin miners in China) that provides data on
whether risks from radon progeny are
different for children, Adolescents, and
adults. Based on this study, the committee
concluded that there was no clear indication
of an effect of age at exposure, and the
committee made no adjustments in the model
for exposures received at early ages. This
indicates that children are not an especially
susceptible sub-group. With respect to cancer
risk from ingestion of radon, NAS (1999b)
performed an analysis to investigate the
relative contribution of radon ingestion as a
child to the total risk. This analysis
considered the age dependence of water
consumption, of the behavior of radon and its
decay products in the body, of organ size,
and of risk. The results indicated that dose
coefficients are somewhat higher in younger
people than adults. NAS (1999b) estimated
that about 30 percent of a lifetime risk was
due to exposures occurring during the first 10
years of life.
Uncertainty of radon risk estimates:
Several commenters said EPA needs to
provide a more in-depth discussion of the
uncertainty associated with the risk estimates
for radon.
EPA Response: EPA has performed a very
detailed two-dimensional Monte Carlo
evaluation of variability and uncertainty in
exposure and risk from water-borne radon
(USEPA 1993, 1995). The methods and
inputs used by EPA were reviewed by the
SAB and by NAS, and the results were
judged to be appropriate and sound, subject
to some refinements in the uncertainty
bounds on some of the inputs. Based on the
most recent recommendations from the NAS
regarding the uncertainty in the risk
coefficient for ingestion and inhalation
exposure, EPA (1999d) has recalculated the
uncertainty bounds around each risk
estimate. In brief, the credible interval
around the best estimate of individual and
population risks from inhalation and
ingestion exposure pathways are about four-
fold and fourteen-fold, respectively.
Extrapolation of high dose in mines to
lower dose in homes: Many commenters
stated that the differences in dose between
the mines and homes in the 1991 NAS report
Comparative Dosimetry of Radon in Mines
and Homes needs to be incorporated into the
Agency's radon progeny inhalation risk
calculation.
EPA Response: EPA and NAS both
recognize the importance of potential
differences between dose and risk per unit
exposure in mines and in homes. The ratio
of the dose to lung cells per WLM in the
home compared to that in a mine is described
by the K factor. Based on the best data
available at the time, NAS (1991) had
previously concluded that the dose to target
cells in the lung was typically about 30
percent lower for a residential exposure
compared to an equal WLM exposure in
mines (i.e., K=0.7). The BEIR VI committee
re-examined the issue of the relative
dosimetry in homes and mines. In light of
new information regarding exposure
conditions in home and mine environments,
the committee concluded that, when all
factors are taken into account, the dose per
WLM is nearly the same in the two
environments (i.e., a best estimate for the K-
factor is about 1) (NAS 1999a). The major
factor contributing to the change was a
downward revision in breathing rates for
miners. Thus, NAS has concluded that the
risk coefficient based on miners is
appropriate for use in residences without
adjustment.
Possible confounding factors in mine
studies: Some commenters raised questions
about the possible confounding factors in the
miner epidemiological studies EPA used to
project lung cancer risks. Commenters state'd
that, besides radon, exposure to other
contaminants not found at home can produce
synergistic effects. Such other contaminants
could include diesel fumes, excessive dust
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(which may be a problem in poorly
constructed mines without adequate
ventilation), and other radionuclides like
uranium In the mine air.
EPA Response: The effects on radon risk
estimates from potentially toxic exposures to
substances such as silica, uranium dust,
blasting fumes, and engine exhaust to
underground miner cohorts were carefully
examined in the NAS reports on radon risks
(NAS 1988. 1999a) and other studies. For
example, in the Malmberget iron miner
study. Radford and St. Clair Renard (1984)
Investigated and determined that the risk
from confounders such as tuberculosis, dust,
silica, diesel exhaust, metals and asbestos is
negligible, Edling and Axelson (1983) found
the Grangeberg mine atmosphere clean of
arsenic, asbestos and carcinogenic metals. In
the Eldorado miner cohort (NAS 1988),
potential confounders were investigated and
exposures to silica and diesel exhaust were
very low. In the Czechoslovakian uranium
miners' study, Sevc et al, (1984. 1988) found
that cigarette smoking was the only risk
factor other than radon that was a significant
exogenic carcinogenic agent. Two of the
studies (China and Ontario) have quantitative
data on arsenic, and there was no significant
variation in excess relative risk per unit
radon exposure across different levels of
arsenic exposure (NAS 1999a). Despite the
variety of exposures to potentially toxic
agents other than radon, the dose-response
between radon and lung cancer death was
approximately consistent across the mining
cohorts. NAS (1988) also noted that animal
studies show no evidence of a synergistic
effect of these agents on lung cancer risk from
radon. Taken together, these findings
Indicate that the effect of confounding factors
on observed lung cancer rates in miners is
likely to be small,
Radon-smoking Interaction: Several
commenters stated that EPA's analysis shows
that smoking acts synergistically with radon
to Induce lung cancer. The risk from radon
Is. on average, ten times higher for smokers
than for the restof the population, and over
20 times higher for heavy smokers. Several
commenters asked why they should spend
resources to remove a natural contaminant
from water while more than % of the related
cancer risk is attributable to the
subpopulation who smoke.
EPA Response: Because of the strong
influence of smoking on the risk from radon,
the BE1R VI committee (NAS 1999a)
evaluated risk to ever-smokers and never-
smokers separately. The BEIR VI committee
had smoking information on five of the miner
cohorts, from which they concluded that
there was a submultiplicative interaction
between radon and smoking in causing lung
cancer. Based on current smoking prevalence
rates, it is estimated that about 84 percent of
all radon-induced lung cancers will occur in
ever-smokers, with only 16 percent in never-
smokers. Thus, it is true that a reduction in
radon exposure will save more cancer cases
in the cohort of smokers than nonsmokers,
but the relative amount of risk reduction is
actually greater for nonsmokers than
smokers.
Eptdemlological studies of lung cancer In
ttie home environment. Some commenters
stated that in estimating risk associated with
exposure to radon, EPA should consider
health risk data associated with the exposure
to low levels of radon in the domestic
environment.
EPA Response: The NAS (1999a) has
recently performed a careful analysis of
epidemiological data on the risk of cancer in
residents from radon. The NAS committee
concluded that because of numerous design
and experimental limitations, these studies
do not constitute an adequate data base from
which quantitative risk estimates can be
derived. However, the data from studies in
residents are considered to be generally
consistent with the predictions based on the
miner data.
Lack of experimental or epidemiological
data link exposure via ingestion to increased
cancer rates: Several commenters stated that
no experimental or epidemiologic data link
exposure via ingestion to increased cancer
rates. The basis for ingestion risk data was a
surrogate gas, xenon-133, that behaves
similarly to radon.
EPA Response: Although no human or
animal data directly demonstrate cancer risk
from ingestion of radon, it is certain that
ingested radon is absorbed from the
gastrointestinal tract into the body, that this
absorbed radon is distributed to internal
tissues which are then irradiated with alpha
particles as the radon and its progeny
undergo decay. That alpha irradiation
increases cancer risk is well established
(UNSCEAR 1988; NAS 1990).
EPA's ingestion risk estimate is based on
the conclusions from the NAS Radon in
Drinking Water committee (NAS 1999b). The
NAS committee performed a re-evaluation of
the risks from ingestion of radon in direct tap
water using the basic approach described in
Federal Guidance Document 13 (USEPA
1998). This involved developing a new
pharmacokinetic model of the behavior of
ingested radon, based primarily on
observations of the behavior of ingested
radon in humans, as well as studies using
xenon and other noble gases. NAS also
addressed the uncertainties (within an order
of magnitude) of the risk estimates for oral
exposure associated with dose estimate to the
stomach and in the epidemiologic data used
to estimate the risk (NAS 1999b). Because the
magnitude of the risk posed by ingestion is
about 10 percent of the risk from inhalation
of radon progeny, these uncertainties are not
most critical in evaluating the overall hazards
from water-borne radon.
Air-water transfer factor and episodic
exposure: As for inhalation exposure, most
commenters supported EPA's proposed
radon water-to-air transfer ratio of 10,000:1.
Two commenters regarded this transfer factor
as too conservative.
EPA Response: EPA has performed a
detailed evaluation of radon gas transfer from
water to air (USEPA 1993, 1995). Values are
highly variable between buildings, with an
average value of about 1E-04. The NAS has
recently performed an independent review of
both measured and modeled values, and the
NAS committee also concluded that a value
of 1E-04 is the best point estimate available
(NAS 1999b).
Outdoor versus indoor radon
concentrations: Some commenters asserted
that the concentration of radon in outdoor air
is higher than the indoor air concentration
resulting from the proposed MCL of 300
pCi/L.
EPA Response: EPA agrees. The NAS
committee reviewed all the ambient radon
concentration data that are available, and
based on these data concluded that the best
estimate of the average ambient (outdoor)
radon concentration in the United States is
0.4 pCi/L of air. In contrast, based on a
transfer factor of lxlO~4, the contribution to
indoor air from an average radon
concentration in water (about 213 pCi/L) is
only about 0.021 pCi/L. However, some
groundwater systems have much higher
radon concentrations, and increments in
indoor air from water-borne radon may be
much higher in those cases. As required by
the Congress. EPA is implementing the MMM
program to address the issue of relative radon
risk from water and air.
Direct tap water ingestion rate: Concerning
ingestion intake, few commenters expressed
an opinion on the direct tap water ingestion
rate of 1 L/day. One commenter suggested
that the intake assumption should be 0.7 L/
day, and another, 0.25 L/day.
EPA Response: EPA has based its current
assessment of this issue on reports by the
National Academy of Sciences and others.
The reader is referred to a fuller discussion
in the preamble to today's proposed radon in
drinking water regulation and to references
cited therein (see Section XII).
Radon loss via volatilization prior to
ingestion: Two commenters felt that the 20
percent radon loss from direct tap water
before ingestion is conservative.
EPA Response: Data are limited on the
amount of radon lost from direct tap water
before ingestion. Several studies (von Doblln
and Lindell 1964; Hursh 1965; Suomela and
Kahlos 1972; Gesell and Prichard 1980;
Horton 1982) suggest a value of about 20
percent as the central estimate of radon lost
before direct ingestion. Because of the lack of
data, the NAS (1999b) recommended that a
value of 0 percent (i.e., no loss) be assumed.
It is important to note that this applies only
to "direct tap water", and that radon loss is
assumed to be nearly complete from other
types of water (coffee, juice, that in foods,
etc.).
Concerning the potential additional loss
from the stomach prior to absorption, EPA
believes that radon does not escape from the
esophagus. An available study (Correia et al.
1987) conducted by the Massachusetts
General Hospital specifically measured
exhaled air following ingestion of radioactive
xenon in drinking water. Gas did not
immediately escape through the mouth.
However, the absorption through the stomach
and small intestine transferred xenon to the
bloodstream and lungs. The pharmacokinetic
model used to evaluate risk from ingested
radon utilizes this absorption mechanism.
New studies indicating reduced lung
cancer risk: Some commenters asserted that
the lung cancer risk estimates will be
reduced based on new studies.
EPA Response: The risk coefficients for
lung cancer derived by NAS (1999a, 1999b)
are based on a detailed analysis of all of the
currently available studies.
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Relative risk of radon from soil versus
radon from drinking water: Many
commenters stated that the risks posed by
radon in water are small compared to the risk
of radon from soil, and that regulation of
radon in water will have very little effect in
reducing the total risk of cancer from radon
exposure.
EPA Response: EPA recognizes that the
risk to residents contributed by radon in
household water is a relatively small fraction
of the risk contributed by radon released into
indoor air from soil. Based on the most recent
quantitative analysis, NAS estimates that this
fraction is only about 1 percent.
Nevertheless, it is still true that radon in
water is one of the most hazardous
substances in public water systems,
contributing a total of about 160-170 cancer
deaths per year. Thus, regulation of radon in
water is appropriate.
Cancer risk posed by radon in drinking
water: Radon in drinking water is one of the
water contaminants with the highest
estimated cancer risk.
EPA Response: EPA agrees, and it is for
this reason that EPA believes that regulation
of radon in water is necessary and
appropriate. By definition, because radon is
a known human carcinogen, the MCLG is
zero.
E. Maximum Contaminant Level
Opposition to a radon MCL of300pCi/L:
More than 300 commenters representing
trade associations, Federal and State
agencies, and regional and community water
suppliers disagreed with a standard of 300
pCi/L for radon in drinking water. The
strongest opposition came from California,
Nebraska, and the northeastern region of the
United States. Other commenters suggested
the MCL be set at 1,000 pCi/L or at 2,000 pCi/
L.
EPA Response: As referenced in Section A
of this Appendix, the SDWA as amended in
1996 provides EPA authority to utilize an
alternative approach (AMCL with MMM
programs), which is expected to significantly
allay concerns of stakeholders and
commenters on the 1991 proposal.
Use of cost-effectiveness in standard
setting: Local water agencies throughout
California and elsewhere in the United States
insisted that water rates would double,
resulting in economic problems. State and
local water agencies were in almost
unanimous agreement that the proposed
standard may not be cost-effective, posing
significant financial and administrative
burdens on agencies and customers.
EPA Response: In the past, EPA generally
limited consideration of economic costs
under the SDWA to whether a treatment
technology was affordable for large public
water systems. Under the SDWA as amended
in 1996, the Agency has conducted
considerable analysis in the areas of cost and
technologies for small systems implementing
the radon MCL and on small system
compliance technologies. (For more
information on related EPA analyses refer to
today's proposal.)
The MCL as proposed in 1991 and in
today's action was set within the EPA
regulatory target range of approximately 10~4
to 10 ~6 individual lifetime fatal cancer risk
level, to ensure the health and safety of the
country's drinking water supply. Although
this level will prevent numerous fatal cancer
cases per year, the Agency recognizes that
this benefit would affect only radon in
ground water or 5 percent of the total radon
exposure. The Agency expects the proposed
AMCL/ multimedia approach will result in
greater radon risk reduction at lower cost.
(The multimedia mitigation program and the
projected costs and benefits are described in
greater detail in today's proposal.)
Impact on private wells: Several
commenters expressed concern over the
potential impact of the proposed standards
on private wells.
EPA Response: The Agency cannot
comment on the impact of an NPDWR (radon
standard) on private wells. EPA currently
possesses some data from State surveys that
indicate relatively high levels of radon in
private wells. However, the data are distinct
from Public Water System data collected by
EPA and others. The statute regulates public
water systems that provide piped water for
human consumption to at least 15 service
connections or that serve an average of at
least 25 people for at least 60 days each year.
Public water systems can be community;
non-transient, non-community: or transient
non-community systems. As a supplement to
Federal coverage, some States extend their
authority by regulating systems serving 10
people or fewer.
F. Analytical Methods
Availability of qualified laboratories and
personnel: Commenters stressed the impact
the proposed regulation may have on
requirements for analytical laboratory
certification and training of laboratory
technicians. For example, one State wrote
that it has no certification process through
which laboratories can receive State
certification for radionuclide analyses.
Another commenter stressed the need for a
strategy to work with individual States to
ensure sufficient certified analytical
laboratory capacity.
EPA Response: The current situation and
expected changes in the processes governing
laboratory approval and certification are
discussed in some detail in today's preamble
(Section VIII.B). One of the changes since
1991 is the formation of the National
Environmental Laboratory Accreditation
Conference (NELAC) in 1995. NELAC serves
as a voluntary national standards-setting
body for environmental laboratory
accreditation, and includes members from
both state and Federal regulatory and non-
regulatory programs having environmental
laboratory oversight, certification, or
accreditation functions. The members of
NELAC meet bi-annually to develop
consensus standards through its committee
structure. These consensus standards are
adopted by participants for use in their own
programs in order to achieve a uniform
national program in which environmental
testing laboratories will be able to receive one
annual accreditation that is accepted
nationwide. The intent of the NELAC
standards setting process is to ensure that the
needs of EPA and State regulatory programs
are satisfied in the context of a uniform
national laboratory accreditation program.
EPA shares NELAC's goal of encouraging
uniformity in standards between primacy
States regarding laboratory proficiency
testing and accreditation.
Fpur-day holding period between sampling
and analysis: Several commenters contended
that for laboratories to cope with the
increased number of samples, the holding
period should increase to eight days. A State
agency suggested a'holding period of seven
days. Another commenter stated that the
proposed four-day holding period was not
possible because many ground water systems
have sources distributed over large areas that
may need sampling. Certified personnel will
collect, record, package, and send the
samples to analytical laboratories within four
days. Also, with a 100-minute counting time
requirement, commercial laboratories may be
ill-equipped to analyze samples from 28,000
systems. Another State commented that the
four-day holding period was not compatible
with a standard work week.
Response: Standard Method 7500-Rn
reports a 50 minute counting time (not 100
minutes) and a four day sample holding time.
This combination of counting time and
holding time has been determined to be a
good trade-off, given the limitation of the 3.8
day half-life of radon. Doubling the sample
holding time (i.e., eight days) would
approximately triple the counting time (i.e.,
to 150 minutes) necessary to achieve the
same level of certainty in the analytical
results, which would probably result in
much higher analytical costs. Since the
sample counting procedure is capable of
being highly automated, EPA believes that
certified laboratories will be able to process
the required samples with a four-day holding
time. As an example, one laboratory
contacted by EPA currently analyzes radon in
12,000 water samples per year as part of a
ground water monitoring study, providing
evidence that a demand for radon analytical
capacity will result in the required laboratory
capacity. Based on an evaluation of the
potential for laboratory certification,
performance testing, and analytical
procedures, which included input from
stakeholders, the four day holding time has
been determined to be feasible, and should
result in lower analytical costs than a longer
holding time and a longer counting time.
Proposed analytical techniques: A
commenter representing a group of utilities
approved of direct, low-volume liquid
scintillation for measurement of radon as
proposed, but recommended the use of Lucas
Cell de-emanation for measurement of Ra-
226 (not also for radon, as proposed).
According to this commenter, the liquid
scintillation method for radon measurement
is straightforward and efficient compared
with the Lucas Cell method that requires a
high degree of specialized skill. Also,
equipment cost for the Lucas Cell method
may be prohibitive. The Conference of
Radiation Control Program Directors stated
that liquid scintillation, while able to detect
radon in water at low levels, may provide
laboratory results that are not reliable.
EPA Response: EPA agrees that LSC has
the stated advantages relative to de-
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emanation, EPA also expects that the vast
majority of nationwide radon analysis will be
done using LSC. However, some laboratories
are already equipped to perform the de-
emanation method. Since the de-emanation
method performs acceptably well, there is no
reason to refuse the possibility of the added
laboratory capacity afforded by the approval
of this method.
Precision variability: A local water agency
and an engineering company representative
stated that the 30% precision variability is
Inadequate for determining compliance
because of the extensive natural variability in
radon levels over time. The combination of
counting error, sampling error, and holding
time variability demands a precision of
±20%, which would lead to more consistent
data.
EPA Response: EPA agrees that the 1991
proposal of an acceptance level of ± 30%,
based on a radon "practical quantitation
level" (PQL) of 300 pCi/L is not supportable.
This conclusion is based on an extensive
collaborative study of the liquid scintillation
method and the de-emanation method for
radon published by EPA in 1993, as
described in the methods section (VHI.b) of
the preamble to this proposal. Today's
proposal contains several options for
ensuring that compliance monitoring is
performed using radon methods with
acceptable accuracy and precision. Based on
other comments to the 1991 radionuclides
proposal. EPA's preferred option is that the
method detection limit (MDL) be used as the
measure of sensitivity for radon, and not a
PQL, consistent with the use of the MDL as
the basis for sensitivity in the current
radionuclides rule. EPA is proposing a value
of 12 ± 12 pCi/L as the MDL for radon.
Based on the collaborative study data,
EPA's best recommendation for acceptance
limits for performance evaluations is ± 5%
for single measurements, and for triplicate
measurements. ± 6% at the 95% confidence
level, and ± 9% at the 99% confidence level.
G. Treatment Technologies and Cost
Water Treatment Costs: Industry groups
and several utilities provided detailed
analyses of unit treatment costs for removal
of radon in water. Water treatment cost
estimates prepared by a consultant were up
to five times the costs estimated by EPA. An
analysis produced by a consultant showed
that among the different factors influencing
annual compliance costs estimated by them,
unit treatment costs have the largest impact.
EPA Response: EPA disagrees that its
radon aeration treatment estimates
supporting the 1991 radionuclides proposal
were under-estlmates. EPA analyzed the
aeration cost model and the cost elements
put forward by the industry commenters and
summarized the major differences between
the EPA and industry models. This summary
may be obtained from the docket supporting
today's proposal (USEPA 1992). While this
summary accounts for the differences in cost
estimates between EPA and the industry and
utility estimates, it is not necessary to go into
detail regarding these differences since
overwhelming evidence suggests that EPA's
1992 cost estimates were much closer to
actual unit costs, based on costs reported in
case studies collected since 1991 (USEPA
1999a, AWWARF 1998a) than the
commenter's estimates. A comparison of
EPA's current unit capital cost estimates to
actual capital costs reported in published
case studies can be found in Figure VIII.A. 1
of this preamble. The consultant's 1991
estimates are compared against case studies
and against EPA's current estimates in an
EPA memorandum dated July 28, 1999
(USEPA 1999b). In summary, the consultant's
estimates over-estimated the small systems
case studies by factors ranging from three for
small systems with design flows of around 1
MGD down to around 0.3 MGD. For the
smallest systems case studies (systems
serving around 0.015 MGD), the consultant's
estimates were high by a factor of more than
twenty. For large systems, the consultant's
estimates were two to three times higher than
the best fit for the large system case studies.
As can be seen in Figure VIII.A.l ("Total
Capital Costs: Aeration Cost Case Studies"),
EPA's current unit capital cost estimates
appear to be very conservative compared to
small systems case studies (systems with
design flows less than 1 MGD) and are
typical of case studies for larger flows (design
flows greater than 1 MGD). It should be noted
the costs reported for these case studies are
total capital costs and include all process
costs, as well as pre- and post-treatment
capital costs, land, buildings, and permits.
Figures VIII.A. 1 through VIII.A.3 shown in
the preamble provide strong evidence that
EPA's assumptions affecting its unit cost
estimates are realistic for large systems and
are conservative for small systems.
Additional Treatment—Disinfection:
Commenters asserted that some systems may
need to add disinfection treatment to protect
aerated water supplies from biological
contamination. It was also stated that about
58 percent of small systems and 12 percent
of large systems may need to add disinfection
technology.
EPA Response: The current cost analysis
assumes that all systems adding aeration and
GAC will disinfect. For those systems not
already disinfecting (proportions estimated
from the EPA 1997 Community Water System
Survey), it was assumed that systems adding
treatment would also add disinfection.
Pretreatment for Iron and Manganese: A
commenter also challenged EPA's position
on the minimal pretreatment of a ground
water supply before air stripping of radon.
The commenter presumed that iron and
manganese fouling will require additional
treatment. While the comment did not
address the costs to pre-treat water for iron
and manganese removal, it was mentioned
this pretreatment would result in high
potential costs to water systems.
EPA Response: EPA has re-evaluated its
assumptions regarding iron and manganese
(Fe/Mn) fouling and has included costs for
chemical stabilization (sequestration) of Fe/
Mn for 25% of small systems and 15% of
large systems. Based on an analysis of the
occurrence of Fe/Mn in raw and finished
ground water, EPA believes that this is
adequate to account for Fe/Mn control. Data
sources for this evaluation were: "National
Inorganics and Radionuclides Survey"
(NIRS); American Water Works Association,
"Waten/Stats, 1996 Survey: Water Quality".
and U.S. Geological Survey, "National Water
Information System"). This analysis is more
fully discussed in Section VIII of the
preamble. EPA reiterates that if its Fe/Mn
cost assumptions were invalid, this fact
would be demonstrated in comparisons of its
estimates of capital and O&M costs against
those reported in the case studies cited in the
preamble. As described previously, EPA's
unit cost estimates are apparently
conservative for small systems and seem to
be typical of large systems.
Aeration as BAT and Use of Carbon
Treatment: A major commenter and a city in
California asserted that aeration treatment for
radon could potentially create a problem in
air emissions permitting. Also, a major
commenter commented that systems with
high radon levels in water could produce
high levels of radon in off-gas, potentially
creating a shift among utilities to activated
carbon treatment and waste (radioactive)
disposal problems.
EPA Response: EPA discusses this concern
in some detail in Section VIII of the
preamble, including an evaluation of the
estimates of the potential risks. Results from
a survey of nine California air permitting
agencies regarding permitting requirements
and costs for radon treatment is also
described in the preamble. The full text of
this survey is reported in EPA 1999a.
Centralized Treatment Assumption:
Commenters from the regulated community
challenged EPA's cost analysis assumption
involving centralized water treatment for
radon. These associations cited the then-
current EPA Community Water Supply
Survey of 1986 and the then-current Water
Industry Database. They suggested
centralized treatment facilities were
unrealistic and under predicts the costs to
public water systems. The industry asserted
that the number of wells and well groupings
per system (with numbers increasing with
increasing system size) will likely determine
the number of treatment sites. An industry
group produced estimated distributions of
the percent of systems that would require
treatment sites.
EPA Response: Centralized treatment was
not assumed in the current radon cost
analysis. EPA's current estimate of national
compliance costs for the proposed radon rule
uses the distribution of wells (treatment sites)
per ground water system as a function of
water system size from the 1997 Community
Water System Survey (USEPA 1997). EPA
assumed that a given system's total flow
would be evenly distributed between the
total number of wells at the system. To
estimate the radon occurrence at a particular
well within a system with multiple wells,
EPA used its evaluation of intra-system
occurrence variability (the variability of
radon occurrence between wells within a
given system) to estimate individual well
radon levels. If multiple wells were predicted
to be impacted at a given system, the cost
model assumes that treatment is installed at
each well requiring treatment.
Integrated approach to waste management:
Three commenters declared that compliance
with the radionuclides rule will create
radioactive waste that may or may not be
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Federal Register/Vol. 64, No. 211/Tuesday, November 2, 1999/Proposed Rules
disposable. They recommended an integrated
environmental management approach in
addressing this waste issue.
EPA Response: The Agency used an
integrated environmental management
approach to determine BAT in removing
contaminants from drinking water. While
Packed Tower Aeration (PTA), the BAT for
radon, does not generate waste requiring
disposal, granular activated carbon is of
concern. While not BAT, granular activated ,
carbon may be used by very small systems to
remove radon. Waste disposal issues
regarding GAC treatment for radon are
discussed in some detail in Section VIII of
this preamble. For more information, see
NAS 1999b and AWWARF 1998a and
AWWARF 1998b;
H. Compliance Monitoring
Sampling location: Four State
environmental/health agencies, one private
non-environmental firm, eight public water
suppliers, and one water association
suggested that radon sampling of the
distribution system at the point of entry does
not allow systems to account for decay and
aeration of radon during distribution.
According to these commenters, sampling is
more effective closer to the point of use.
EPA Response: EPA's proposal requires
sampling at the entry points to the
distribution system to assure compliance
with the MCL for the water delivered to every
customer. All samples will be required to be
finished water, as it enters the distribution
system after any treatment and storage. This
approach allows systems to account for the
decay and aeration of radon during treatment
and storage before it enters the distribution
system and at the same time offers maximum
protection to the consumer. It is expected
that radon levels would progressively
decrease within the distribution system,
downstream from the point of entry.
Therefore, consumers who are located closest
to the point of entry are exposed to higher
levels of radon that those further
downstream. In order to assure maximum
protection to all of the consumers, EPA
requires sampling at the entry points to the
distribution system.
Compliance period: Clarification
concerning the frequency of compliance
periods, specifically in regards to the specific
timing for the commencement of water
systems monitoring is warranted.
EPA Response: The proposed monitoring
requirements for radon are consistent with
the monitoring requirements for regulated
drinking water contaminants, as described in
the Standardized Monitoring Framework
(SMF) promulgated by EPA under the Phase
II Rule of the National Primary Drinking
Water Regulations (NPDWR) and revised
under Phases IIB and V. The goal of the SMF
is to streamline the drinking water
monitoring requirements by standardizing
them within contaminant groups and by
synchronizing monitoring schedules across
contaminant groups.
Systems already on-line must begin initial
monitoring for compliance with the MCL/
AMCL by the compliance dates specified in
the rule (i.e., 3 years after the date of
promulgation or 4.5 years after the date of
promulgation). New sources connected on-
line must satisfy initial monitoring
requirements.
Initial compliance with the MCL/AMCL
will be determined based on an average of 4
quarterly samples taken at individual
sampling points in the initial year of
monitoring. Systems with averages exceeding
the MCL/AMCL at any well or sampling
point will be deemed to be out of
compliance. Systems exceeding the MCL/
AMCL will be required to monitor quarterly
until the average of 4 consecutive samples
are less than the MCL/AMCL. Systems will
then be allowed to collect one sample
annually if the average from four consecutive
quarterly samples is less than the MCL/
AMCL and if the State determines that the
system is reliably and consistently below
MCL/AMCL.
Systems that primarily use surface water,
supplemented with ground water: One water
association suggested that public water
systems supplementing their surface water
supply with ground water are not in
violation. Since the actual lifetime risk
involved is significantly lower than those
systems using 100 percent ground water
supply, an equitable method of compliance
for this type of combined systems should be
administered.
EPA Response: In today's proposal,
systems relying exclusively on surface water
as their water source are not required to
sample for radon. Systems that rely in part
on ground water during low-flow periods
about one quarter of the year are considered
public ground water systems. According to
the ground water monitoring requirements,
systems are subject to monitor finished water
at each entry point to the distribution system
for radon during periods of ground water use.
For the purpose of determining compliance,
systems supplementing their surface water
during part of the year will use a value of '/z
the detection limit for radon for averaging
purposes for the quarters when the water
system is not supplemented by ground water.
The water system having ground water
samples supplementing surface water with a
radon detection level above the MCL would
not be out of compliance provided that these
samples do not cause the average to exceed
the MCL when averaged with the value of l/z
the detection limit during the quarters the
ground water source is not in use.
Averaging quarterly samples: Commenters
recommended clarifying the discussion
concerning the averaging of initial
measurements to determine compliance.
They stated that averaging the first year
quarterly samples with the.annual second
and third compliance years will defeat the
purpose of quarterly samples detecting signs
of seasonal variability.
EPA Response: EPA is retaining the
quarterly monitoring requirement for radon .
as proposed initially in the 1991 proposal to
account for variations such as sampling,
analytical and temporal variability in radon
levels. Results of analysis of data obtained
since 1991, estimating contributions of
individual sources of variability to overall
variance in the radon data sets evaluated,
indicated that sampling and analytical
variance contributes less than 1 percent to
the overall variance. Temporal variability
within single wells accounts for between 13
and 18 percent of the variance in the data
sets evaluated, and a similar proportion (12-
17 percent) accounts for variation in radon
levels among wells within systems (USEPA
1999c).
For today's proposal, the Agency
performed additional analyses to determine
whether the requirement of initial quarterly
monitoring for radon was adequate to
account for seasonal variations in radon
levels and to identify non-compliance with
the MCL/AMCL. Results of analysis based on
radon levels modeled for radon distribution
for ground water sources and systems
(USEPA 1999c) in the U.S. show that the
average of the first four quarterly samples
provides a good indication of the probability
that the long-term average radon level in a
given source would exceed an MCL or
AMCL. Tables A.I and A.2 show the
probability of the long-term average radon
level exceeding the MCL and AMCL at
various averages obtained from the first four
quarterly samples from a source.
TABLE A.1.—THE RELATIONSHIP BE-
TWEEN THE FIRST-YEAR AVERAGE
RADON LEVEL AND THE PROBABILITY
OF THE LONG-TERM RADON AVER-
AGE RADON LEVELS EXCEEDING THE
MCL
If the average of the first four
quarterly samples from a
source is:
Less than 50 pCi/L
Between 50 and 100 pCi/L
Between 100 and 150 pCi/L ...
Between 150 and 200 pCi/L ...
Between 200 and 300 pCi/L ...
Then the
probability
that the long-
term average
radon level in
that source
exceeds 300
pCi/L is:
0 percent
0.5 percent
0.4 percent
7.2 percent
26.8 percent
TABLE A.2.—THE RELATIONSHIP BE-
TWEEN THE FIRST-YEAR AVERAGE
RADON LEVEL AND THE PROBABILITY
OF THE LONG-TERM RADON AVER-
AGE RADON LEVELS EXCEEDING THE
AMCL
If the average of the first four
quarterly samples from a
source is:
Less than 2,000 pCi/L
Between 2,000 and 2,500
pCi/L.
Between 2,500 and 3,000
pCi/L.
Between 3,000 and 4,000
pCi/L.
Then the
probability
that the long-
term average
radon level in
that source
exceeds
1000 pCi/L
Less than
0.1 percent
9.9 percent
15.1 percent
32.9 percent
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59369
Water systems with a history of
compliance: EPA has provided for the
grandfathoring of prior monitoring data for
granting waivers. Monitoring data collected
after January 1, 1985, that are generally
consistent with the requirements of the
section, and includes at least one sample
taken on or after January 1. 1993, may be
accepted by the State to satisfy the initial
monitoring requirements. Many systems
meeting the current monitoring requirements
should qualify for this grandfathering
provision because each sampling point or
source water intake will be monitored within
the preceding four-year period. New
sampling points, or sampling points with
new sources, must take an initial sample
within the year the new source or sampling
point begins operation.
EPA Response: Today's proposal provides
that at a State's discretion, sampling data
collected after the proposal could be used to
satisfy the initial sampling requirements for
radon, provided that the system has
conducted a monitoring program not less
stringent than that specified in the regulation
and used analytical methods specified in the
proposed regulation. The Agency wants to
provide water suppliers with the opportunity
to synchronize their monitoring program
with other contaminants and to get an early
Start on their monitoring program if they
wish to do so.
The proposed regulation provides for the
States to grant monitoring waiver reducing
monitoring frequency to once every nine
years (once per compliance cycle) provided
the system demonstrates that it is unlikely
that radon levels in drinking water will occur
above the MCL/AMCL. In granting the
waiver, the State must take into
consideration factors such as the geological
area where the water source is located, and
previous analytical results which
demonstrate that radon levels do not occur
above the MCL/AMCL. The waiver will be
granted for up to a nine year period. (Given
that all previous samples are less than Vz the
MCL/AMCL, then it is highly unlikely that
the long-term average radon levels would
exceed the MCL/AMCL.)
References Cited in Appendix 1 to the
Preamble
American Water Works Association Research
Foundation. Critical Assessment of Radon
Removal Systems for Drinking Water
Supplies. Denver, CO. [December 1998]
[AWWARF 1998a]
American Water Works Association Research
Foundation. Assessment of GAC
Adsorption for Radon Removal. Final
Draft. Denver. CO. [April 1998] [AWWARF
1998b]
Correia. J.A., Weise, S.B.. Callahan, R.J., and
Strauss, H.W. The Kinetics of Ingested Rn-
222 in Humans Determined from
Measurements with Xe-133. Massachusetts
General Hospital, Boston, MA,
unpublished report (As cited in Crawford-
Brown 1990). [1987] [Correia, et al. 1987]
Crawford-Brown. D.J. Final Report: Risk and
Uncertainty Analysis for Radon in
Drinking Water. American Water Works
Association, Denver, CO. [1992] [Crawford-
Brown 1992]
Edling, C. and Axelson, O. Quantitative
Aspects of Radon Daughter Exposure and
Lung Cancer in Underground Miners, Br. J.
Ind.Med. (40:182-187) [1983] [Edling and
Axelson 1983]
Ershow, A.G. and Cantor, K.P. Total Water
and Tapwater Intake in the United States:
Population-based Estimates of Quantities
and Sources. Report prepared under
National Cancer Institute Order #263-MD-
810264. [1989] [Ershow and Cantor 1989]
Federal Register, Vol. 64, No. 38. Health Risk
Reduction and Cost Analysis (HRRCA) for
Radon in Drinking Water: Notice, Request
for Comments and Announcement of
Stakeholder Meeting. (Feb. 26, 1999) 9559-
9599. [64 FR 9559]
Field, R.W., Fisher, E.L., Valentine, R.L., and
Kross, B.C. Radium-Bearing Pipe Scale
Deposits: Implications for National
Waterborne Radon Sampling Methods.
Am.J. Public Health (85:567-570) [April
1995] [Field et al. 1995]
Gesell, T.F. and Prichard, H.M. The
Contribution of Radon in Tap Water to
Indoor Radon Concentrations. In: Gesell
T.F. and W.M. Lowder, eds. Natural
radiation environment III, Vol. 2.
Washington, DC: U.S. Department of
Energy, Technical Information Center, pp.
1347-1363. CONF-780422 (Vol. 2). [1980J
[Gesell and Prichard 1980]
Horton, T.R. Results of Drinking Water
Experiment. Memorandum from T.R.
Horton of the Environmental Studies
Branch to Charles R. Phillips. [1982]
[Horton 1982]
Hursh, J.B., Morken, D.A. Davis, T.P., and
Lovaas, A. The Fate of Radon Ingested by
Man. Health Phys. (11:465-476). [1965]
[Hursh, etal. 1965]
Kinner, N.E., Malley, J.P., and Clement, J.A.
Radon Removal Using Point-of-Entry Water
Treatment Techniques. EPA/600/2-90/047.
Cincinnati, OH: Risk Reduction
Engineering Laboratory. [1990] [Kinner, et
al. 1990]
National Academy of Sciences, National
Research Council. Health Risk of Radon
and Other Internally Deposited Alpha-
Emitters: (BEIRIV) National Academy
Press, Washington, DC. [1988] [NAS 1988]
National Academy of Sciences, National
Research Council. Health Effects of
Exposure to Low Levels of Ionizing
Radiation (BEIR V). National Academy
Press, Washington, DC. [NAS 1990]
National Academy of Sciences, National
Research Council. Comparative Dosimetry
of Radon in Mines and Homes. National
Academy Press, Washington, DC. [NAS
1991]
National Academy of Sciences, National
Research Council. Health Effects of
Exposure to Radon. (BEIR VI.) National
Academy Press, Washington, DC. [NAS
1999a]
National Academy of Sciences, National
Research Council, Committee on the Risk
Assessment of Exposure to Radon in
Drinking Water, Board on Radiation Effects
Research. Risk Assessment of Radon in
Drinking Water. National Academy Press,
Washington, DC. [NAS 1999b]
National Institute of Occupational Safety and
Health. Criteria for a Recommended
Standard: Occupation Exposure to Radon
Progeny in Underground Mines. U.S.
Government Printing Office. (1987]
[NIOSH 1987]
Pennington, J.A. Revision of the Total Diet
Study Food List and Diets. J. Am. Diet.
Assoc. (82:166-173) [1983] [Pennington
1983]
Radford, E.P. and St. Clair Renard, K.G. Lung
Cancer in Swedish Iron Miners Exposed to
Low Doses of Radon Daughters. N. Engl. J.
Med. (310(23):1485-1494) [1984] [Radford
and St. Clair Renard 1984]
Sevc J., Kunz, E., Placek, V., and Smid, A.
Comments on Lung Cancer Risk Estimates.
Health Phys. (46: 961-964) [1984] [Sevc. et
al. 1984]
Sevc, J., Kunz, E., Tomasek, L., Placek, V.,
and Horacek, J. Cancer in Man after
Exposure to Rn Daughters. Health Phys.
(54:27-46) [1988] [Svec, et al. 1988]
Suomela M. and Kahlos, H. Studies on the
Elimination Rate and the Radiation
Exposure Following Ingestion of 222-Rn
Rich Water. Health Phys. (23:641-652)
[1972] [Suomela and Kahlos 1972]
United Nations Scientific Committee on the
Effects of Atomic Radiation. Sources,
Effects and Risks of Ionizing Radiation.
United Nations, NY. [1988] [UNSCEAR
1988]
U.S. Environmental Protection Agency,
Office of Radiation Programs. An
Estimation of the Daily Average Food
Intake by Age and Sex for Use in Assessing
the Radionuclide Intake of Individuals in
the General Population. EPA 520/1-84-
021. [1984] [USEPA 1984]
U.S. Environmental Protection Agency.
Examination of Kennedy/Jenks Cost
Estimates for Radon Removal by Packed
Column Air Stripping. Memorandum to
Marc Parrotta, ODW, from Michael
Cummins, ODW. [November 23, 1992]
[USEPA 1992]
U.S. Environmental Protection Agency,
Office of Science and Technology, Office of
Radiation and Indoor Air, Office of Policy,
Planning, and Evaluation. Uncertainty
Analysis of Risks Associated with
Exposure to Radon in Drinking Water. TR-
1656-3B. [April 30, 1993] [USEPA 1993]
U.S. Environmental Protection Agency,
Office of Water. Report to United States
Congress on Radon in Drinking Water:
Multimedia Risk Assessment of Radon.
EPA-811-R-94-001. [March 1994] [USEPA
1994]
U.S. Environmental Protection Agency,
Office of Science and Technology, Office of
Radiation and Indoor Air, Office of Policy,
Planning and Evaluation. Uncertainty
Analysis of Risks Associated with
Exposure to Radon in Drinking Water. EPA
822-R-96-005. [March, 1995] [USEPA
1995]
U.S. Environmental Protection Agency,
Office of Ground Water and Drinking
Water. Community Water System Survey.
Volume II: Detailed Survey Result Tables
and Methodology Report. EPA 815-R-97-
0016. [January 1997] [USEPA 1997]
U.S. Environmental Protection Agency,
Office of Radiation and Indoor Air. Health
Risks from Low-Level Environmental
Exposure to Radionuclides. Federal
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Guidance Report No. 13. Part I—Interim
Version. EPA 401/R-97-014. [1998]
[USEPA 1998]
U.S. Environmental Protection Agency.
Technologies and Costs for the Removal of
Radon from Drinking Water. Prepared by
Science Applications International
Corporation for EPA. [May 1999] [USEPA
1999a]
U.S. Environmental Protection Agency.
EPA's Unit Capital Cost Estimates for
Aeration for Radon Treatment Versus
AWWA and ACWA's Estimates from 1992
(Kennedy/Jenks Report) and AWWARF
1995. Memorandum to Sylvia Malm,
OGWDW, from William Labiosa, OGWDW.
[July 28, 1999] [USEPA 1999b]
U.S. Environmental Protection Agency,
Office of Ground Water and Drinking
Water. Methods, Occurrence and
Monitoring Document for Radon. Draft.
[Augusts, 1999] [USEPA 1999c]
U.S. Environmental Protection Agency,
Office of Science and Technology. Draft
Criteria Document for Radon in Drinking
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Valentine, R., Stearns, S., Kurt, A., Walsh, D.,
and Mielke, W. Radon and Radium from
Distribution System and Filter Media
Deposits. Presented at AWWA Water
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[November, 1992] [Valentine et al. 1992]
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List of Subjects
40 CFR Part 141
Environmental protection, Chemicals,
Indians—lands, Intergovernmental
relations, Radiation protection,
Reporting and recordkeeping
requirements, Water supply.
40 CFR Parti 42
Environmental protection.
Administrative practice and procedure,
Chemicals, Indians—lands. Radiation
protection, Reporting and recordkeeping
requirements. Water supply.
Dated: October 19, 1999.
Carol M. Browner,
Administrator.
For the reasons set out in the
preamble, the Environmental Protection
Agency proposes to amend 40 CFR parts
141 and 142 as follows:
PART 141—NATIONAL PRIMARY
DRINKING WATER REGULATIONS
1. The authority citation for part 141
continues to read as follows: .
Authority: 42 U.S.C. 300f, 300g-l, 300g-2,
300g-3, 300g-4, 300g-5, 300g-6, 300J-4,
300J-9, and300j-ll.
2. Section 141.2 is amended by
adding definitions of "Alternative
Maximum Contaminant Level (AMCL)"
and "Multimedia Mitigation (MMM)
Program Plan" in alphabetical order, to
read as follows:
§141.2 Definitions.
*****
Alternative Maximum Contaminant
Level (AMCL) is the permissible level of
radon in drinking water delivered by a
community water system in a State with
an EPA-approved multimedia mitigation
(MMM) program plan, or by a
community water system with a State-
approved local MMM program plan.
*****
Multimedia Mitigation (MMM)
Program Plan is a State or community
water system program plan of goals and
strategies developed with public
participation to promote indoor radon
risk reduction. MMM programs for
radon in indoor air may use a variety of
strategies, including public education,
testing, training, technical assistance,
remediation grant and loan or incentive
programs, or other regulatory or non-
regulatory measures.
*****
3. Section 141.6 is amended by
adding paragraph (j) to read as follows:
141.6 Effective dates.
* * * * *
(j) The regulations set forth in Subpart
R of this part are effective [60 days after
date of publication of the final rule in
the Federal Register].
Subpart C—[Amended]
4. A new § 141.20 is added to Subpart
C to read as follows:
§ 141.20 Analytical methods, monitoring,
and compliance requirements for radon.
(a) Analytical methods. (1) Analysis
for radon shall be conducted using one
of the methods in the following table:
PROPOSED ANALYTICAL METHODS FOR RADON IN DRINKING WATER
Methodology
Liauid Scintillation Counting
De-emanation , :
References (method or page number)
SM
7500-Rn1 ....
ASTM
D 5072 922
EPA
EPA 1987 3
1 Standard 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.
2 American 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.
3 Appendix D, Analytical Test Procedure, "The Determination of Radon in Drinking Water". In "Two Test Procedures for Radon in Drinking
Water, Intel-laboratory Collaborative Study". EPA/600/2-87/082. March 1987. p. 22.
(2) Sample collection for radon shall be conducted using the sample preservation, container, and maximum holding
time procedures specified in the following table.
SAMPLING METHODS AND SAMPLE HANDLING, PRESERVATION, AND HOLDING TIME
Sampling methods
(i) As described in SM 7500— Rn1
Preservative
Ship sample
in an insu-
lated pack-
age to
avoid large
tempera-
ture
changes.
Sample
Container
Glass with
teflon-lined
septum.
Maximum
holding time
for sample
4 days.
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59371
Sampling Methods and Sample Handling, Preservation, and Holding Time
Sampling methods
(ii) As described in EPA 1987*.
Preservative
Sample
Container
Maximum
holding time
for sample
1 Standard 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.
a"Two Test Procedures for Radon in Drinking Water, Interlaboratory Collaborative Study". EPA/600/2-87/082. March 1987.
(b) Monitoring and compliance requirements. Community water systems (CWSs) shall conduct monitoring to determine
compliance with the maximum contaminant level (MCL) or alternate maximum contaminant level (AMCL) specified
in §141.66 in accordance with this chapter. The monitoring requirements have been developed to be consistent with
the Phase II/V monitoring schedule.
(1) Applicability and sampling
location. CWSs using a ground water
source or CWSs using ground water and
surface water sources (for the purpose of
this section hereafter referred to as
systems) shall sample at every entry
point to the distribution system which
is representative of each well after
treatment and/or storage (hereafter
called a sampling point) under normal
operating conditions in accordance with
paragraph (b)(2) of this section.
(2) Monitoring—(i) Initial monitoring
requirements. (A) Systems must collect
four consecutive quarterly samples
beginning by the date specified in
§141.301(b).
(B) States may allow previous
sampling data collected after [60 days
after date of publication of the final
rule) to satisfy the initial monitoring
requirements, provided the system has
conducted monitoring to satisfy the
requirements specified in this section. If
a system's early monitoring data
indicates an MCL/AMCL exceedence,
the system will not be considered in
violation until the end of the applicable
initial monitoring period specified in
§141,301(b).
(ii) Routine monitoring requirements.
Systems must continue quarterly
monitoring until the running average of
four consecutive quarterly samples is
less than the MCL/AMCL. If the running
average of four consecutive quarterly
samples is less than the MCL/AMCL
then systems may conduct annual
monitoring at the State's discretion.
(HI) Reduced monitoring
requirements. States may allow systems
to reduce the frequency of monitoring to
once every three years (one sample per
compliance period) beginning the
following compliance period provided
the systems:
(A) Demonstrate that the average of
four consecutive quarterly samples is
below V5s MCL/AMCL;
(B) No individual samples exceed the
MCL/AMCL; and
(C) The States determine that the
systems are reliably and consistently
below the MCL/AMCL.
(iv) Increased monitoring
requirements. (A) Systems which
exceed the MCL/AMCL shall monitor
quarterly beginning the quarter
following the exceedence. States may
allow systems to reduce their
monitoring frequency if the
requirements specified in paragraph
(b)(2)(iti) or (b) (2) (iv) (B) of this section
are met.
(B) Systems monitoring once every
three years, or less frequently, which
exceed Vz MCL/AMCL shall begin
annual monitoring the year following
the exceedence. Systems may reduce
monitoring to once every three years if
the average of the initial and three
consecutive annual samples is less than
l/z MCL/AMCL and the State determines
the system is reliably and consistently
below the MCL/AMCL.
(C) If a community water system has
a portion of its distribution system
separable from other parts of the
distribution system with no
interconnections, increased monitoring
need only be conducted at points of
entry to those portions of system.
(v) Failure to conduct monitoring as
described in this section is a monitoring
violation.
(3) Monitoring waivers, (i) States may
grant a monitoring waiver to systems
provided that:
(A) The system has completed initial
monitoring requirements as specified in
paragraph (b)(2)(i) of this section.
Systems shall demonstrate that all
previous analytical results were less
than Vz MCL/AMCL. New systems and
systems using a new ground water
source must complete four consecutive
quarters of monitoring before the system
is eligible for a monitoring waiver; and
(B) States determine that the systems
are reliably and consistently below the
MCL/AMCL, based on a consideration
of potential radon contamination of the
source water due to the geological
characteristics of the source water
aquifer.
(ii) Systems with a monitoring waiver
must collect a minimum of 1 sample
every nine-years (once per compliance
cycle).
(iii) A monitoring waiver remains in
effect until completion of the nine-year
compliance cycle.
(iv) A decision by States to grant a
monitoring waiver shall be made in
writing and shall set forth the basis for
the determination.
(4) Confirmation samples. Systems
may take additional samples to verify
initial sample results as specified by the
State. The results of the initial and
confirmation samples will be averaged
for use in calculation of compliance.
(5) Compliance. Compliance with
§ 141.66 shall be determined based on
the analytical result(s) obtained at each
sampling point. If one sampling point is
in violation, the system is in violation.
(i) For systems monitoring more
frequently than annually, compliance
with the MCL/AMCL is determined by
a running annual average at each
sampling point. If the average at any
sampling point is greater than the MCL/
AMCL, then the system is out of
compliance with the MCL/AMCL.
(ii) If any one quarterly sampling
result will cause the running average to
exceed the MCL/AMCL, the system is
out of compliance.
(iii) Systems monitoring annually or
less frequently whose sample result
exceeds the MCL/AMCL will revert to
quarterly sampling immediately. The
system will not be considered in
violation of the MCL/AMCL until they
have completed one year of quarterly
sampling.
(iv) All samples taken and analyzed
under the provisions of this section
must be included in determining
compliance, even if that number is
greater than the minimum required.
(v) If a system does not collect all
required samples when compliance is
based on a running annual average of
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quarterly samples, compliance will be
based on available data.
(vi) If a sample result is less than the-
detection limit, zero will be used to
calculate the annual average.
(vii) During the initial monitoring
period, if the compliance determination
for a system in a non-MMM State
exceeds the MCL, the system will incur
a MCL violation unless the system
notifies the State by [four years after
date of publication of the final rule in
the Federal Register] of their intent to
submit a local MMM plan, submits a
local MMM plan to the State within [5
years after date of publication of the
final rule in the Federal Register] and
begins implementation by [5.5 years
after date of publication of the final rule
in the Federal Register]. The State shall
approve or disapprove a local MMM
program plan within 6 months from the
date of receipt. If the State does not
disapprove the local MMM program
plan during such period, then the CWS
shall implement the plan submitted to
the State for approval. The compliance
determination will be conducted as
described in this paragraph.
(viii) Following the completion of the
initial monitoring period, if the
compliance determination for a system
in a non-MMM State exceeds the MCL, .
the system will incur a MCL violation
unless the system submits a local MMM
plan to the State within 1 year from the
date of the exceedence and begins
implementation 1.5 years from the date
of the exceedence. The State shall
approve or disapprove a local MMM
program plan within 6 months from the
date of receipt. If the State does not
disapprove the local MMM program
plan during such period, then the CWS
shall implement the plan submitted to
the State for approval. The compliance
determination will be conducted as
described in this paragraph.
(6) If a community water system has
a distribution system separable from
other parts of the distribution system
with no interconnections, the State may
allow the system to give public notice
to only the area served by that portion
of the system which is out of
compliance.
5. Section 141.28 is revised to read as
follows:
§ 141.28 Certified laboratories.
• (a) For the purpose of determining
compliance with § 141.20 through
141.27, 141.41, and 141.42, samples
may be considered only if they have
been analyzed by a laboratory certified
by the State except that measurements
for turbidity, free chlorine residual,
temperature and pH may be performed
by any person acceptable to the State.
(b) Nothing in this part shall be
construed to preclude the State or any
duly designated representative of the
State from taking samples or from using
the results from such samples to
determine compliance by a supplier of
water with the applicable requirements
of this part.
Subpart F—[Amended]
6. A new § 141.55 is added to Subpart
F to read as follows:
§ 141.55 Maximum contaminant level goals
for radionuclides.
MCLGs are as indicated in the
following table:
Contaminant
Radon-222
MCLG
Zero.
Subpart G—[Amended]
7. A new § 141.66 is added to Subpart
G to read as follows:
§ 141.66 Maximum contaminant level for
radionuclides.
(a) The maximum contaminant level
for radon-222 is as follows: (1) A
community water system (CWS) using a
ground water source or using ground
water and surface water sources that
serves 10,000 or fewer people shall
comply with the alternative maximum
contaminant level (AMCL) of 4000 pCi/
L, and implement a State-approved
multimedia mitigation (MMM) program
to address radon in indoor air (unless
the State in which the system is located
has a MMM approved by the
Environmental Protection Agency).
These systems may elect to comply with
the MCL of 300 pCi/L instead of
developing a local CWS MMM program
plan.
(2) A CWS using a ground water
source or using ground water and
surface water sources that serves more
than 10,000 people shall comply with
the MCL of 300 pCi/L, except that the
system may comply with an AMCL of
4000 pCi/L where:
(i) The State in which the CWS is
located has adopted an MMM program
plan approved by EPA; or,
(ii) The CWS has adopted an MMM
program plan approved by the State.
(3) A CWS shall monitor for radon in
drinking water according to the
requirements in § 141.20, and report the
results to the State, and continue to
monitor as described in § 141.20. If the
State determines that the CWS is in
compliance with the MCL of 300 pCi/L,
the CWS has met the requirements of
this section and is not subject to the
requirements of subpart R of this part,
regarding MMM programs.
(4) The Administrator, pursuant to
section 1412 of the Act, hereby
identifies, as indicated in the following
table, the best technology available for
achieving compliance with the
maximum contaminant levels for radon
identified in paragraphs (a)(l) and (a) (2)
of this section:
BAT for Radon-222
High-Performance Aeration1
(5) The Administrator, pursuant to
section 1412 of the Act, hereby
identifies in the following table the best
technology available to systems serving
10,000 persons or fewer for achieving
compliance with the MCL or AMCL.
The table addresses affordability and
technical feasibility for such BAT.
PROPOSED SMALL SYSTEMS COMPLIANCE TECHNOLOGIES (SSCTS)1
EFFICIENCIES.
AND ASSOCIATED CONTAMINANT REMOVAL
Small systems compliance
Packed Tower Aeration (PTA)
High Performance Package Pla
Multi-Stage Bubble Aeration, J
ation).
Diffused Bubble Aeration
technology
nt Aeration (e g
Shallow Tray Aer-
Affordable for listed small
systems categories2
All Size Categories
AH Size Categories
All Size Cateaories
Removal efficiency
90— >99.9% Removal
90— > 99 9% Removal
70 to >99% removal
Operator level
required 3
Intermediate
Basic to Inter-
mediate.
Basic
Limitations
(see foot-
notes)
(a)
(a)
(a. W
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.
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59373
PROPOSED SMALL SYSTEMS COMPLIANCE TECHNOLOGIES (SSCTS)1 AND ASSOCIATED CONTAMINANT REMOVAL
EFFICIENCIES—Continued
Small systems compliance technology
Tray Aeration . ...
Spray Aeration . . * ...
Mechanical Surface Aeration
Centralized Granular activated carbon
Point-of-Entry (POE) granular activated carbon
Affordable for listed small
systems categories 2
All Size Categories .
All Size Categories
All Size Categories
May not be affordable,
except for very small
flows.
May be affordable for sys-
tems serving fewer than
500 persons.
Removal efficiency
80 to >90%
80 to >90% ... .
>90%
50 to >99% Removal
50 to >99% Removal ..
Operator level
required 3
Basic
Basic
Basic
Basic
Basic
Limitations
(see foot-
notes)
(a c)
(a d)
(a e)
m
ff a)
1 Section 1412(b)(4)(E)(ii) of the SDWA specifies that SSCTs must be affordable and technically feasible for small systems.
2The Act (Ibid.) specifies three categories of small systems: i) those serving 25 or more, but fewer than 501, ii) those serving more than 500,
but fewer than 3,301, and iii) those serving more than 3,300, but fewer than 10,001.
3 From 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 effi-
ciencies. Q 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.
Subpart O — [Amended]
8. Section 141.151 is amended by
revising paragraph (d) to read as
follows:
141.151 Purpose and applicability of this
subpart.
*****
(d) For the purpose of this subpart,
detected means: at or above the levels
prescribed by § 141.23(a)(4) for
inorganic contaminants, at or above the
levels prescribed by § 141.24(f)(7) for
the contaminants listed in § 141. 61 (a), at
or above the level prescribed by
§ 141.24(h)(18) for the contaminants
listed in § 14 1.61 (c), at or above the
level prescribed by § 141.66 for radon,
and at or above the levels prescribed by
§ 141.25(c) for radioactive contaminants.
*****
9. Section 141.153 is amended by
revising paragraph (d)(l)(i); removing
paragraph (e)(2) and redesignating
paragraph (e)(3) as (e)(2); redesignating
paragraphs (f)(5), (f)(6), and (f)(7) as
(f)(6), (f)(7), and (f)(8); and adding
paragraph (f)(5) to read as follows:
§ 1 41 .1 53
**
(d) * * *
Content of the reports.
***
(i) Contaminants subject to a MCL,
AMCL, action level, or treatment
technique (regulated contaminants);
*****
(0***
(5) Local multimedia radon mitigation
programs prescribed by subpart R of this
part.
*****
10. Section 141.154 is amended by
adding paragraph (f) as follows:
§ 141.154 Required additional health
information.
*****
(f) In each complete calendar year
between [date of publication of final
rule in the Federal Register] and [4
years after date of publication of the
final rule in the Federal Register], each
report from a system that has ground
water as a source must include the
following notice (except that a system
developing a local MMM program in a
non-MMM State needs to include this
statement in each calendar year between
[date of publication of the final rule in
the Federal Register] and [5 years after
date of publication of the final rule in
the Federal Register] :
Radon is a naturally-occurring radioactive
gas found in soil and outdoor air that may
also be found in drinking water and indoor
air. Some people exposed to elevated radon
levels over many years in drinking water may
have an increased risk of getting cancer. The
main health risk is lung cancer from radon
entering indoor air from soil under homes.
Your water system plans to test for radon by
[insert date], and if radon is detected your
water system will provide the results of
testing to their customers. The best way to
reduce the overall risk from radon is to
reduce radon levels in indoor air. Some
States, and water systems, may now be
working to develop a program to reduce
radon exposure in indoor air and drinking
water. To get more information and to help
develop the program, call the Radon Hotline
(800-SOS-RADON) or visit the web site
http://www.epa.gov/iaq/radon/.
Subpart Q—[Amended]
11. In §141.201, Table 1 proposed on
May 13, 1999, at 64 FR 25964 is
amended by revising paragraphs (1)
introductory text and (l)(i) to read as
follows:
§ 141.201 General Public Notification
Requirements.
*****
Table 1 to § 141.201—Violation
Categories and Other Situations
Requiring a Public Notice.
(1) NPDWR violations (MCL/AMCL,
local MMM, MRDL, treatment
technique, monitoring and testing
procedure)
(i) Failure to comply with an
applicable maximum contaminant level
(MCL), alternative maximum
contaminant level (AMCL), the local
multimedia mitigation requirement for
small systems in non-MMM States, or
maximum residual disinfectant level
(MRDL).
*****
12. In § 141.203, Table 1 proposed on
May 13, 1999, at 64 FR 25964 is
amended by revising paragraph (1) to
read as follows:
§ 141.203 Tier 2 Public Notice—Form,
manner, and frequency of notice.
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Federal Register/Vol. 64, No. 211/Tuesday, November 2, 1999/Proposed Rules
Table 1 to § 141.203. Violation
Categories and Other Situations
Requiring a Tier 2 Public Notice
(1) All violations of the MCL, AMCL,
MRDL, and treatment technique
requirements not included in the Tier 1
notice category;
*****
13. In § 141.204, Table 1 proposed on
May 13, 1999, at 64 FR 25964 is
amended by adding paragraph (5) to
read as follows:
§ 141.204. Tier 3 Public Notice—Form,
manner, and frequency of notice.
*****
Table 1 to § 141.204. Violation
Categories and Other Situations
Requiring a Tier 3 Public Notice
(5) All violations of the MMM
requirements not included in the Tier 1
or 2 notice category;
*****
14. Section 141.205 proposed on May
13, 1999, at 64 FR 25964 is amended by
revising paragraph (d)(l), to read as
follows:
§ 141.205 Content of the public notice.
*****
(d) * * *
(1) Standard health effects language
for MCL, AMCL, MMM or MRDL
violations, treatment technique
violations, and violations of the
condition of a variance or exemption.
Public water systems must include in
each public notice the health effects
language specified in Appendix B to
this subpart corresponding to each MCL,
AMCL, MMM, MRDL, and treatment
technique violation listed in Appendix
A to this subpart, and for each violation
of a condition of a variance or
exemption.
*****
15. Part 141 is amended by adding a
new Subpart R to read as follows:
Subpart R—Reducing Radon Risks In
Indoor Air and Drinking Water
Sec.
141.300 Applicability.
141.301 General requirements.
141.302 Multimedia mitigation (MMM)
requirements (required elements of
MMM program plans).
141.303 Multimedia mitigation (MMM)
reporting and compliance requirements.
141.304 Local multimedia mitigation
program plan approval and program
review.
141.305 States that do not have primacy.
Subpart R—Reducing Radon Risks in
Indoor Air and Drinking Water
§141.300 Applicability.
(a) The requirements of this subpart
constitute national primary drinking
water regulations for radon. The
provisions of this subpart apply to
community water systems (CWS) using
a ground water source or using ground
water and surface water sources. CWSs
must monitor for radon in drinking
water according to the requirements
described in § 141.20, and report the
results to the State, and continue to
monitor as described in § 141.20. If the
State determines that the CWS is in
compliance with the MCL of 300 pCi/L,
the CWS has met the requirements of
this section and is not subject to the
requirements of this subpart.
(b) These regulations in this subpart
establish criteria for the development
and implementation of program plans to
mitigate radon in indoor air and
drinking water (multimedia mitigation
or MMM program plan). In general,
where a State, CWS, or Tribal MMM
program plan is approved, CWSs
comply with an AMCL of 4000 pCi/L
(§ 141.66). In jurisdictions without an
approved MMM program plan, large
CWSs (serving greater than 10,000
people) must comply with an MCL of
300 pCi/L (§141.66), except they
comply with the AMCL of 4000 pCi/L
if they develop a CWS MMM program
plan approved by the State. Small
community water systems serving
10,000 or fewer people must comply
with 4000 pCi/L and implement a State-
approved multimedia mitigation
program plan to address radon in indoor
air (unless the State in which the system
is located has a multimedia mitigation
program plan approved by the
Environmental Protection Agency);
these systems have the option of
complying with the MCL instead of
implementing a MMM program.
§141.301 General requirements.
(a) The requirements for the MMM
program plan are set out in this subpart.
The requirements for the MCL are set
out in § 141.20(a) (analytical methods),
§141.20(b) (monitoring and
compliance), § 141.66(a) through (c)
(requirements for systems, including
MCL and AMCL), and § 141.66(d)
(BAT).
(b) Compliance dates.—(1) Initial
monitoring, (i) For States that submit a
letter to the Administrator by [90 days
after date of publication of the final rule
in the Federal Register] committing to
develop an MMM program plan in
accordance with section
1412(b)(13){G)(v) of the Act, CWSs must
begin one year of quarterly monitoring
for compliance with the AMCL by [4.5
years after date of publication of the
final rule in the Federal Register].
(ii) For States not submitting a letter
to the Administrator by [90 days after
date of publication of final rule in the
Federal Register] committing to develop
an MMM program plan, CWSs must
begin one year of quarterly monitoring
for compliance with the MCL/AMCL by
[3 years after date of publication of final
rule in the Federal Register].
(2) State-wide MMM programs, (i) For
States that submit a letter to the
Administrator by [90 days after date of
publication of the final rule in the
Federal Register] committing to develop
an MMM program plan in accordance
with section 1412 (b) (13) (G) (v),
implementation of the State-wide MMM
program must begin by [4.5 years after
date of publication of the final rule in
the Federal Register].
(ii) For States not submitting a letter
to the Administrator by [90 days after
date of publication of the final rule in
the Federal Register] committing to
develop an MMM program plan, but
which subsequently decide to adopt the
AMCL, implementation of the State-
wide MMM program must begin by [3
years after date of publication of the
final rule in the Federal Register].
(iii) If EPA-approval of a State MMM
program plan is revoked, all systems
have one year from notification by the
State to comply with the MCL. If a
system chooses to continue complying
with the AMCL and develop and
implement a local MMM program, the
State will specify a timeframe for
compliance.
(3) Local MMM programs, (i) During
the initial monitoring period, if the
compliance determination for a CWS in
a non-MMM State exceeds the MCL, the
CWS will incur an MCL violation unless
the system notifies the State by [four
years after date of publication of the
final rule in the Federal Register] of
their intent to submit a local MMM
plan, submits a local MMM plan to the
State within [5 years after date of
publication of the final rule in the
Federal Register] and begins
implementation by [5.5 years after date
of publication of the final rule in the
Federal Register]. The compliance
determination will be conducted as
described in § 141.20(b)(2).
(ii) Following the completion of the
initial monitoring period, if the
compliance determination for a CWS in
a non-MMM State exceeds the MCL, the
system will incur an MCL violation
unless the system submits a local MMM
plan to the State within 1 year from the
date of the exceedence and begins
implementation 1.5 years from the date
of the exceedence. The compliance
determination will be conducted as
described in this paragraph.
(iii) The State shall approve or
disapprove a local MMM program plan
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59375
within 6 months from the date of
receipt, If the State does not disapprove
the local MMM program plan during
such period, the CWS shall implement
the plan submitted to the State for
approval,
(iv) If the State determines the CWS
is not adequately implementing the
local MMM plan approved by the State,
the system shall incur an MMM
violation.
(v) During the MMM program 5-year
review periods, the system shall incur
an MMM violation if the State
determines the CWS is not meeting
MMM program plan objectives.
§141.302 Multimedia mitigation (MMM)
requirements (required elements of MMM
program plans).
The following are required for
approval of State MMM program plans
by EPA. Local MMM program plans
developed by community water systems
(CWS) 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, means any entity
submitting an MMM program plan for
approval, including States, with and
without primacy, Indian Tribes and
community water systems.
(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:
(i) 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 paragraphs
(b), (c), and (d) of this section;
(il) A description of the nature and
extent of public participation that
occurred, including a list of groups and
organizations that participated;
(iii) 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
(iv) 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.
(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.
(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.
(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 paragraph (b) of this
section. 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 radon-
resistant 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 paragraph (b) of this
section, 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
community 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 paragraph (b) of
this section. This specifically includes a
description of the methodologies the
State will use to determine or track the
number or rate 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 assessments available to the
public.
(2) If a State includes goals 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 of these
assessments available to the public.
§ 141.303 Multimedia mitigation (MMM)
reporting and compliance requirements.
(a) In accordance with the Safe
Drinking Water Act (SDWA), EPA is to
review State MMM programs at least
every five years. For the purposes of this
review, the States with EPA-approved
MMM program plans shall provide
written reports to EPA in the second
and fourth years between initial
implementation of the MMM program
and the first 5-year review period, and
in the second and fourth years of every
subsequent 5-year review period. States
that submit a letter to the Administrator
by [90 days after date of publication of
the final rule in the Federal Register]
committing to develop an MMM
program plan, must submit their first 2-
year report by 6.5 years from
publication of the final rule. For States
not submitting the 90-day letter, but
choosing subsequently to submit an
MMM program plan and adopt the
AMCL, the first 2-year report must be
submitted to EPA by 5 years from
publication of the final rule. EPA will
review these programs to determine
whether they continue to be expected to
achieve risk reduction of indoor radon
using the information provided in the
two biennial reports.
(b) (1) These reports are required to
include the following information:
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(i) A quantitative assessment of
progress towards meeting the required
goals described in § 141.302(b),
including the number or rate of existing
homes mitigated and the number or rate
of new homes built radon-resistant since
implementation of the States' MMM
program, and,
(ii) A description of accomplishments
and activities that implement the
required program strategies, described
in § 141.302(c), outlined in the
implementation plans and in the two
required areas of promoting increased
testing and mitigation of existing homes
and promoting increased use of radon-
resistant techniques in construction of
new homes.
(2) If goals were defined as rates, the
State must also provide an estimate of
the number of mitigations and radon-
resistant new homes represented by the
reported rate increase for the two-year
period.
(3) If the MMM program plan includes
goals for promoting public awareness of
the health effects of indoor radon,
testing of homes by the public; testing
and mitigation of existing schools; and
construction of new public schools to be
radon-resistant, the report is also
required to include information on
results and accomplishments in these
areas.
(c) If EPA determines that a MMM
program is not achieving progress
towards its goals, EPA and the State
shall collaborate to develop
modifications and adjustments to the
program to be implemented over the
five year period following the review.
EPA will prepare a summary of the
outcome of the program evaluation and
the proposed modification and
adjustments, if any, to be made by the
State.
(d) If EPA determines that a State
MMM program is not achieving progress
towards its MMM goals, and the State
repeatedly fails to correct, modify and
adjust implementation of their MMM
program after notice by EPA, EPA will
withdraw approval of the State's MMM
program plan. CWSs in the State would
then be required to comply with the
MCL, or develop a State-approved CWS
MMM program plan. The State will be
responsible for notifying CWSs of the
Administrator's withdrawal of approval
of the State-wide MMM program plan.
EPA will work with the State to
establish a State process for review and
approval of CWS MMM program plans
that meet the required criteria,
including local public participation in
development and review of the program
plan, and a time frame for submission
of program plans by CWSs that choose
to continue complying with the AMCL.
(e) States shall make available to the
public each of these two-year reports
identified in paragraph (a) of this
section, as well as the EPA summaries
of the five-year reviews of a State's
MMM program, within 90 days of
completion of the reports and the
review.
(f) In primacy States without a State-
wide MMM program, the States shall
provide a report to EPA every five-years
on the status and progress of CWS
MMM programs towards meeting their
goals. The first of such reports would be
due by [10.5 years after date of
publication of the final rule in Federal
Register].
§141.304 Local multimedia mitigation
program plan approval and program review.
(a) In States without an EPA-approved
MMM program plan, any community
water system may elect to develop and
implement a local MMM program plan
that meets the criteria in § 141.302 and
comply with the AMCL in lieu of the
MCL. Local CWS MMM program plans
must be approved by the State.
(b) CWSs with State-approved MMM
program plans shall report to the State
as required by the State. States shall
review such local programs at least
every five years to determine if CWSs
are implementing their program plans
and making progress towards their
goals. If the CWS fails to meet those
requirements, the State shall require the
system to comply with the MCL.
§ 141.305 States that do not have primacy.
(a) If a State, as defined in section
1401 of the Act, that does not have
primary enforcement responsibility for
the Public Water System Program under
section 1413 of the Act chooses to
submit an MMM program plan to EPA,
that program plan must meet the criteria
in § 141.301. EPA will approve such
program plans in accordance with the
requirements of § 141.302.
(b) States with EPA-approved MMM
program plans shall report to EPA in
accordance with the requirements of
§141.303.
PART 142—NATIONAL PRIMARY
DRINKING WATER REGULATIONS
IMPLEMENTATION
1. The authority citation for part 142
continues to read as follows:
Authority: 42 U.S.C. 300f, 300g-l, 300g-2,
300g-3, 300g-4, 300g-5, 300g-6, 300J-4,
300J-9, and300j-ll.
2. Section 142.12 is amended by
adding new paragraph (b) (4) to read as
follows:
§ 142.12 Revision of State programs.
*****
(b) * * *
(4) To be granted an extension for
radon regulatory requirements included
under 40 CFR part 141, subpart R, the
State must commit to adopt the AMCL
and MMM program plan, or MCL.
*****
3. Section 142.15 is amended by
adding new paragraph (c)(6) to read as
follows:
§ 142.15 Reports by States.
* * . * * *
(c) * * *
(6) In accordance with the Safe
Drinking Water Act (SDWA), EPA is to
review State MMM programs at least
every five years. EPA will review these
programs to determine whether they
continue to be expected to achieve risk
reduction of indoor radon using the
information provided in the two
biennial reports. For the purposes of
this review:
(i) (A) States with EPA-approved
MMM program plans shall provide
written reports to EPA in the second
and fourth years between initial
implementation of the MMM program
and the first 5-year review period, and
in the second and fourth years of every
subsequent 5-year review period.
(B) States that submit a letter to the
Administrator by [90 days after date of
publication of the final rule in the
Federal Register] committing to develop
an MMM program plan, must submit
their first 2-year report by [6.5 years
after date of publication of the final rule
in the Federal Register]. For States not
submitting the 90-day letter, but
choosing subsequently to submit an
MMM program plan and adopt the
AMCL, the first 2-year report must be
submitted to EPA by [5 years after date
of publication of the final rule in the
Federal Register].
(ii) These reports are required to
include the following information:
(A) A quantitative assessment of
progress towards meeting the required
goals described in § 141.302(b),
including the number or rate of existing
homes mitigated and the number or rate
of new homes built radon-resistant since
implementation of the States' MMM
program, and
(B) A description of accomplishments
and activities that implement the
required program strategies, described
in § 141.302(c), outlined in the
implementation plans and in the two
required areas of promoting increased
testing and mitigation of existing homes
and promoting increased use of radon-
resistant techniques in construction of
new homes.
(C) If goals were defined as rates, the
State must also provide an estimate of
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59377
the number of mitigations and radon-
resistant new homes represented by the
reported rate increase for the two-year
period.
(D) If the MMM program plan
Includes goals for promoting public
awareness of the health effects of indoor
radon, testing of homes by the public;
testing and mitigation of existing
schools; and construction of new public
schools to be radon-resistant, the report
is also required to include information
on results and accomplishments in
these areas.
(lii) States shall make available to the
public each of these two-year reports, as
well as the EPA summaries of the five-
year reviews of a State's MMM program,
within 90 days of completion of the
reports and the review.
(iv) In primacy States without a State-
wide MMM program, the States shall
provide a report to EPA every five-years
on the status and progress of CWS
MMM programs towards meeting their
goals. The first of such reports would be
due by [10.5 years after date of
publication of the final rule in the
Federal Register].
*****
4. Section 142.16 is amended by
adding new paragraph (i) to read as
follows;
§142.16 Special primacy requirements.
*****
(i) Requirements for States to adopt 40
CFRpart 141, subpartR. In addition to
the general primacy requirements
elsewhere in this part, including the
requirement that State regulations be at
least as stringent as federal
requirements, an application for
approval of a State program revision
that adopts 40 CFR part 141. subpart R.
must contain a description of how the
State will accomplish the program
requirements for implementation of the
AMCL and MMM program plan or the
MCL as follows:
(1) If a State chooses to develop and
implement a State-wide MMM program
plan and adopt the AMCL, the primacy
application must include the following
elements:
(i) A copy of the State-wide MMM
program plan prepared to meet the
criteria outlined in § 141.302 of this
chapter.
(ii) A description of how the State
will make resources available for
implementation of the State-wide MMM
program plan.
(iii) 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
MMM program plan, including the level
of resources that will be made available
for implementation and coordination
between interagency programs (i.e.,
indoor air and drinking water
programs).
(2) If a State chooses to adopt the MCL
the primacy application must contain
the following:
(i) A description of how the State will
implement a program to approve local
CWS MMM program plans prepared to
meet the criteria outlined in § 141.302 of
this chapter and a description of the
State's authority to implement this
program.
(ii) A description of how the State
will ensure local CWS MMM program
plans are implemented.
(iii) A description of reporting and
record keeping requirements for local
CWS MMM programs.
(iv) A description of how the State
will review local CWS program plans at
least every five years to determine if
they are implementing the MMM
program and making progress towards
their goals.
(v) A description of the procedures
and schedule the State will use in
withdrawing State approval of a CWS
MMM program plan and notifying the
CWS that they are required to comply
with the MCL.
(vi) 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 process for review and approval of
CWS MMM program plans. This
description includes the level of
resources that will be made available for
implementation and coordination
between interagency programs (i.e.,
indoor air and drinking water
programs).
(vii) A description of how the State
will make required CWS reports
available to the public.
5. A new § 142.65 is added to subpart
G, to read as follows:
§ 142.65. Variances and exemptions from
the maximum contaminant level for radon.
(a) The Administrator, pursuant to
section 1415(a)(l)(A) of the Act, hereby
identifies in the following table as the
best technology, treatment techniques,
or other means available for achieving
compliance with the maximum
contaminant level for radon:
BAT for Radon-222
1. For all systems: High-Performance
Aeration l
2. For systems serving 10,000 persons
or fewer: High-Performance Aeration l
or 2, Granular Activated Carbon2 (GAC),
and Point-of-Entry GAC 2.
(b) A State shall require a community
water system to install and/or use any
treatment method identified in
paragraph (a) of this section as a
condition for granting a variance, based
upon an evaluation satisfactory to the
State that indicates that alternative
sources of water are not reasonably
available to the system.
(c) Bottled water and/or granular
activated carbon point-of-use devices
cannot be used as means of being
granted a variance or an exemption for
radon.
(d) Community water systems that use
point-of-entry devices as a condition for
obtaining a variance or an exemption
from NPDWRs must meet the following
requirements:
(1) All point-of-entry units shall be
owned, controlled, and maintained by
the community water system or by a
person or persons under contract with
the public water system to ensure
proper operation and maintenance of
the unit under the terms of the variance
or exemption.
(2) All point-of-entry units shall be
equipped with mechanical warning
devices to ensure that customers are
notified of operational problems.
(3) If the American National
Standards Institute has issued product
standards applicable to a specific type
of point-of-entry device for radon,
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.
2 As defined and described in 40 CFR 141.66 (e).
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individual units of that type shall not be
accepted under the terms of the variance
or exemption unless they are
independently certified in accordance
with such standards.
(4) Before point-of-entry devices are
installed, the community water system
must obtain the approval of a
monitoring plan which ensures that the
devices provide health protection
equivalent to analogous centralized
water treatment.
(5) The community water system must
apply effective technology under a
State-approved plan. The
microbiological safety of the water must
be maintained at all times.
(6) The State must require adequate
certification of performance, field
testing, and, if not included in the
certification process, a rigorous
engineering review of the point-of-entry
devices.
(7) The design and application of
point-of-entry devices must consider the
potential for increasing concentrations
of heterotrophic bacteria in water
treated with activated carbon. It may be
necessary to use frequent backwashing,
post-GAC contactor disinfection, and
Heterotrophic Plate Count monitoring to
ensure that the microbiological safety of
the water is not compromised.
6. Section 142.72 is amended by
removing the introductory text, by
redesignating paragraphs (a) through (d)
as (b)(l) through (b)(4), and by adding
a new paragraph (a) to read as follows:
§ 142.72. Requirements for Tribal eligibility.
(a) If a Tribe meets the criteria in
paragraph (b) of this section, the
Administrator is authorized to treat an
Indian Tribe as eligible to apply for:
(1) Primary enforcement
responsibility for the Public Water
System Program:
(2) Authority to waive the mailing
requirements of 40 CFR 141.155(a); and
(3) Authority to develop and
implement a radon multimedia
mitigation program in accordance with
40 CFR part 141, subpart R.
***-**
7. Section 142.78 is amended by
revising paragraph (b) to read as follows:
§ 142.78. Procedure for processing an
Indian Tribe's application.
(b) A Tribe that meets the
requirements of § 142.72 is eligible to
apply for development grants and
primary enforcement responsibility for a
Public Water System and associated
funding under section 1443(a) of the
Act, for primary enforcement
responsibility for public water systems
under section 1413 of the Act, for the
authority to waive the mailing
requirements of 40 CFR 141.155(a), and
for the authority to develop and
implement a radon multimedia
mitigation program in accordance with
40 CFR part 141, subpart R.
8. Part 142 is amended by adding a
new Subpart L to read as follows:
Subpart L—Review of State MMM
Programs
§ 142.400 Review of State MMM programs
and procedures for withdrawing approval of
State MMM programs.
(a) (1) At least every five years, the
Administrator shall review State MMM
programs. For the purposes of this
review, States with EPA-approved
MMM programs shall provide written
reports to the Administrator in the
second and fourth years between initial
implementation of the MMM program
and the first 5-year review period, and
in the second and fourth years of every
subsequent 5-year review period. The
written reports will discuss the status
and progress of their program towards
meeting their MMM goals. The
Administrator will use the information
provided in the two biennial reports in
discussions and consultations with the
State to review the programs to
determine whether they continue to be
expected to achieve risk reduction of
indoor radon.
(2) If the Administrator determines
that a State MMM program is not
achieving progress towards its MMM
goals, the Administrator and the State
shall collaborate to develop
modifications and adjustments to the
program to be implemented over the
five year period following the review.
EPA will prepare a summary of the
outcome of the program evaluation and
the proposed modification and
adjustments, if any, to be made by the
State.
(3) If the State repeatedly fails to
correct, modify or adjust
implementation of its MMM program
after notice by the Administrator, the
Administrator shall initiate proceedings
to withdraw approval of the State's
MMM program plan. The Administrator
shall notify the State in writing that EPA
is initiating withdrawing a State-wide
MMM program plan and shall
summarize in the notice the information
available that indicates that the State is
no longer achieving progress towards its
MMM goals.
(4) The State notified pursuant to
paragraph (a) (3) of this section may,
within 30 days of receiving the
Administrator's notice, submit to the
Administrator evidence that the State
plans to implement modifications to the
State MMM program.
(5) After reviewing the submission of
the State, if any, made pursuant to
paragraph (a) (4) of this section, the
Administrator shall make a final
determination either that the State no
longer continues to achieve progress
towards its MMM goals, or that the State
continues to implement modifications
to the State MMM program, and shall
notify the State of his or her
determination. Before a final
determination that the State no longer
continues to achieve progress towards
its MMM goals, the Administrator shall
offer a public hearing and will publish
a notice in the Federal Register.
(b) If approval of a State's MMM
program is withdrawn, the State will be
responsible for notifying CWSs of the
Administrator's withdrawal of approval
of the State-wide MMM program plan.
The CWSs in the State would then be
required to comply with the MCL. EPA
will work with the State to establish a
State process for review and approval of
CWS MMM program plans that meet the
required criteria and a time frame for
submittal of program plans by CWSs
that choose to continue complying with
the AMCL. The review process will
allow for local public participation in
development and review of the program
plan.
[FR Doc. 99-27741 Filed 10-25-99; 3:12 pm]
BILLING CODE 6560-50-P
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