United States Science Advisory EPA-SAS-OWC-33-015
Environmental Board (A-101) -uly 1993
Proteclion Agency
v>EPA AN SAB REPORT:
[REVIEW OF ISSUES
RELATED TO THE COST
OF MITIGATING INDOOR
RADON RESULTING
FROM DRINKING
WATER
REVIEW OF THE OFFICE OF
GROUNDWATER AND DRINKING
WATER APPROACH TO THE COSTS
OF RADON CONTROL OR
MITIGATION EXPERIENCED BY
HOUSEHOLDS OR COMMUNITIES
-------
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
OFFICE OF THE ADMINISTRATOR
July 29, 1993 SC.ENCE ADVISORY BOARD
EPA-SAB-DWC-93-015
Honorable Carol M. Browner
Administrator
U.S. Environmental Protection Agency
401 M Street SW
Washington, DC 20460
Subject: Review of issues related to the cost of mitigating indoor radon
resulting from drinking water.
Dear Ms. Browner:
The Science Advisory Board (SAB) has completed its review of the Agency's
approach to ascertaining the costs of radon control or mitigation experienced by
households or communities in response to Public Law 102-398, Section 519 (106
STAT 16(18) pertaining to implementation of the Safe Drinking Water Act
(SDWA). This report is part ..fa larger study by the SAB of regulating drinking
water radon levels, cost, uncer.i.nty of risk, and overarching issues.
On February 8 and 9. '.'j'-M. the Radon Engineering Cost Subcommittee
(RECS) of the SAB's Drinking Water Committee (DWC) conducted a review
focused on the following charge :<> determine whether EPA offices are employing
a reasonable approach for estimating the costs of mitigating indoor radon from
drinking water in residences, and whether the technologies that have been judged
by EPA as being Best Available Technology (BAT) for central or well-head
treatment for each size water treatment-facility category are appropriate, and
whether the design, operation, installation and maintenance of these technologies
are reasonably estimated. Additionally, the SAB was asked to address the relative
cost-effectiveness of controlling radon exposure from drinking water in comparison
to controlling other sources of indoor radon. "Effective," in this context, means
the extent to which radon exposure is reduced by the treatment applied to produce
significant reductions in adverse health effects. These results can be normalized
-------
using assumed dose-effect values. The findings and conclusions of the
Subcommittee follow.
1. Exposure Issues
a) The Subcommittee determined that the EPA offices are employing a
reasonable framework for estimating the cost-effectiveness of
mitigating airborne indoor radon from soil and water sources in
residences. The cost factors for testing and mitigation of soil gases
are based on a substantial body of data from actual practice and
represent the consensus of a group of industry experts.
b) Based on one national sampling survey, the average concentration of
radon in potentially regulated U.S. water supplies at point of use (not
well head) is approximately 300 pCi/Lwater in groundwater systems
(100 pCi/L when considering a population-weighted average of ground
and surface water systems); certain state and regional survey data
were not included. EPA estimates that a 300 pCifLw&ier standard
would reduce total risk from radon by approximately 2.5%. However,
assuming an equilibrium ratio of 10,000 to 1, water to household air,
the average contribution to airborne radon from waterborne radon is
estimated to be 0.01 pCi/L^^. This contrasts with an average
indoor airborne radon concentration of between 1 and 1.5 pCi/L^ for
all sources of airborne radon. Regulation of waterborne radon then
will reduce the total airborne radon risk (all sources of radon
considered) by less than 1%. This contribution to the total reduction
of risk (1%) is lessened by the fact that a regulatory limit on
waterborne radon would reduce, not remove radon from all water
supplies. Current estimates are that a regulatory limit of 300
pCi/Lwater would reduce the average U.S. concentration of waterborne
radon to approximately 50% of the present value, indicating that
regulation of waterborne radon at 300 pCi/Lvr&ter would reduce the
total risk of airborne radon by less than 0.5% from the currently
existing risk. By whatever route one arrives at the calculation of
total risk from radon, that is whether it is 0.5% or 2.5%, it most
assuredly is a small risk level compared to soil gas radon.
-------
c) The wide discrepancy between the cost-effectiveness of mitigating
water-borne radon versus soil gas radon underscores the minor role
that waterborne radon plays in the overall indoor health hazard. The
EPA estimates that approximately 80 deaths (range 81-89) could be
avoided per year by reducing all groundwater-based public systems to
300 pCi/Lwater with the maximum individual lifetime risk of fatal
cancer reduced to 2 x 10" .
The most recent cost estimates are about $400M per year, or about
$5M per life saved. On the other hand, the primary source of radon
in indoor air is soil gas which produces an ambient outdoor air
concentration of about 0.4 pCi/L^, and an average indoor
concentration of about 1.3 pCi/L^. EPA estimates that if all homes
with concentrations above 4 pCi/L^ were mitigated with present
technology, then about 3,000 of the 13,600 yearly deaths (range 6740
to 30,600 lung cancer deaths) attributed to indoor radon could be
eliminated, and under this scenario, the cost per life saved would be
about $700,000 and the maximum individual lifetime lung cancer risk
o
reduced to 10 .
2. Cost and Engineering Issues:
a), The Office of Ground water and Drinking Water (OGW&DW) has
approached the development of the unit costs for the removal of
radon from drinking water by the Packed Tower Aeration (PTA)
method using a reasonable framework. Problems do arise in
calculating the total unit costs, however, because of the assumptions
made on the individual items that make up the total unit costs.
Other water treatment authorities have made their own estimates,
using nearly the same approach as OGW&DW, and have estimated
different total costs.
b) With regard to consideration of alternative aeration technologies (that
is, "engineered" versus modular systems) with systems of different
sizes: EPA's estimates are based on the use of a PTA for all system
sizes. Operation and Maintenance (O&M) costs are also based on a
-------
uniform approach for all sizes. Actual costs and practice will vary
with the size of the system installing the treatment. Very small
systems are likely to experiment with a variety of their own informal
designs as well as a variety of packaged systems and their style of
operation and interactions with the public and with regulatory
agencies are likely to be more informal as well. Larger systems are
likely to impose a more formal design, bid, and construction practice
and engender closer regulatory review and greater public input. If
EPA's purpose is to produce an estimate reflecting the most likely
cost, then these estimates should better reflect the impact of system
size on design practice.
c) Certainly PTA is an effective technique for removing radon from
groundwater and qualifies as Best Available Treatment (BAT) for
central treatment. However, there may also be a perceived problem
in using PTA in certain localities because of off-gas dispersal.
Granular Activated Carbon (GAC) was also discussed as a possible
BAT. EPA cited long contact times required and difficulties in
disposing of waste GAC as reasons for rejecting this technology. Yet.
it seems that GAC has been demonstrated to remove radon, and chat
problems of waste disposal may be manageable where influent radon
, levels are modest. Additionally, GAC may be a particularly well
suited technology for the smallest systems, since it could be installed
as an in-line pressure vessel not requiring repumping.
d) The cost of disinfection resulting from radon PTA treatment is a
significant factor in the cost of radon mitigation and should be
explicitly stated for different size systems. Groundwater can be
distributed without disinfection only if the system has appropriate
barriers to contamination by micro-organisms. Also, the cancer r:.-lw
associated with exposures to disinfection by-products were not
discussed.
3. Recommendations:
-------
a) We are pleased that the OGW&DW has recalculated their unit costs
for Packed Tower Aeration (PTA) in response to the comments
already received and recommend that they continue this iterative
process with the commenters and work cooperatively with other
responsible interested parties. We consider this necessary because we
find merit in some of the non-EPA data.
b) We recommend that EPA review its choices for BAT and more
carefully state the reasons for choices made reducing the cost of the
GAG process.
c) Since EPA's purpose is to produce an estimate reflecting the most
likely cost of units, these estimates should more accurately reflect the
impact of system size on design practice.
d) The Subcommittee suggests that summary tables be included in the
report that compare and contrast the impact of several levels of radon
exposure (e.g. 300 pCi/L^^ versus 1000 pCi/Lwater and 3000
pCi/Lwater) on system and national costs including cancer deaths
avoided at various confidence levels. This would be most helpful to
highlight the impact of various remediation efforts to members of
Congress, the states, various water treatment authorities and the
interested public.
e) The EPA analysis shows that mitigating radon from water as
required by the SDWA, is 10 times more expensive than mitigating
radon from soil gas. This regulatory requirement (policy) however,
should not negate logical and practical considerations related to
determining U.S. cost burdens, compared and contrasted to potential
health benefits.
f) One important part of the OGW&DWS cost calculations on which the
SAB does want to comment specifically is that of the Interest rate
assumptions used. Interest rate assumptions markedly impact the
annualized capital costs for radon removal from drinking water. The
operation and maintenance (O&M) costs are insensitive to interest
-------
rates. The SAB recommends that an Interest rate higher than the
3% currently employed by the Agency be used.
g) The cost of disinfection resulting from radon treatment apparently
has not been explicitly itemized In the cost of radon control and the
SAB recommends that this oversight be corrected.
h) The Subcommittee was provided with two thoughtful and detailed
analyses by the American Water Works Association (AWWA) and the
Association of California Water Agencies (ACWA). This commentary
was appreciated by the Subcommittee and provided insights and a
greater diversity of opinion that was useful in our deliberations and
should be considered by EPA in their reevaluation of the radon
issues.
i) The SAB recommends that the OGW&DW participate in the
upcoming "Radon Removal by Packed Tower Stripping" research
project of the AWWA so that they can have their impact on project
design and data collection.
j) Finally, the SAB realizes that it has recommended considerable work
i to be done to make EPA's cost studies more creditable and therefore
recommends that the EPA, if necessary, request from the Courts and
the Congress sufficient time to do the work.
Subsequent to the February meeting of the Subcommittee and prior to the
publication of this SAB report, the OGW&DW provided revised cost estimates to
the Subcommittee. These estimates were not available at the time of the public
meeting, and have not been given the usual public scrutiny and discussion that is
such an integral part of all SAB meetings. Therefore, we have not addressed
them in this report. However, we do recognize that the issues contained in the
revised estimates are of great interest and warrant further public and SAB
interaction in the future.
The SAB has offered a number of broad-ranging, as well as specific findings
and recommendations on the Agency's radon engineering cost and treatment
-------
technology issues. We are pleased to have had the opportunity to be of service to
the Agency. We trust that these comments will help in your guidance of this
important program, and look forward to your response.
Sincerely,
L. Ltohs
Dr. Raymond C. Loehr, Chair Dr. Verne A. Ray, Cl
Executive Committee Drinking Water Committee
Science Advisory Board Science Advisory Board
-------
NOTICE
This report has been written as a part of the activities of the Science
Advisory Board, a public advisory group providing extramural scientific
information and advice to the Administrator and other officials of the
Environmental Protection Agency. The Board is structured to provide a balanced,
expert assessment of scientific matters related to problems facing the Agency.
This report has not been reviewed for approval by the Agency; hence, the
comments of this report do not necessarily represent the views and policies of the
Environmental Protection Agency or of other federal agencies. Any mention of
trade names or commercial products does not constitute endorsement or
recommendation for use.
-------
ABSTRACT
The Radon Engineering Cost Subcommittee (REGS) of the Drinking Water
Committee (DWC) of the EPA Science Advisory Board (SAB) has reviewed the
Agency's approach to the costs of radon control or mitigation experienced by
households or communities. On February 8 and 9, 1993, the Radon Engineering
Cost Subcommittee (REGS) of the SAB's Drinking Water Committee (DWC)
conducted a focused review of the cost issues.
As part of its charge REGS evaluated EPA's approach for estimating the
costs of mitigating indoor radon from drinking water in residences, assessed EPA's
judgement on Best Available Technology (BAT) for central or well-head treatment
for each size water treatment-facility category are appropriate, and reviewed cost
estimates for design, operation, installation and maintenance of these technologies.
The SAB also compared the cost-effectiveness of controlling radon exposure from
drinking water with the costs of controlling other sources of indoor radon.
"Effective," in this context, means the extent to which radon exposure is reduced
by the treatment applied to produce significant improvements in health. These
results can be normalized using calculated dose-effect values.
The Subcommittee determined that the EPA offices are employing a
reasonable framework for estimating the cost-effectiveness of mitigating airborne
indoor raldon in residences. The approach for soil gases embodies standard Agency
and industry methodology, and the cost data for testing and mitigation are based
on a substantial body of data from actual practice and represent the consensus of
industry experts.
The Subcommittee recommends that EPA invite more direct interaction with
various water industry commenters regarding radon removal from drinking water
in order to obtain better data on actual construction, operation, and cost
estimating practice before making its independent judgements. Of particular
concern were the representativeness of the data base on occurrence of radon in
groundwater, the elements used to calculate costs of treatment unit operations, the
effect of system size on unit costs, and the incidence and cost of disinfection after
air stripping.
11
-------
Kev Words: Radon, Radon Engineering Cost, Radon Treatment
111
-------
Science Advisory Board
Radon Engineering Cost Subcommittee
Drinking Water Committee
Dr. Verne A. Ray, Medical Research Laboratory, Pfizer, Inc.; Groton, Connecticut
embes
Dr. Judy A. Bean, University of Miami, Department of Epidemiology, Miami,
Florida
Mr. Keith E. Cams, Cams, Perkins, Associates, Pinole, California
Mr. Richard A. Conway, Union Carbide Corporation, South Charleston, West
Virginia
Dr. Ben B. Ewing, Lu'mmi Island, Washington
Dr. James H. Johnson, Department of Civil Engineering, Howard University,
Washington, DC
Mr. David W. Saum, Infiltec. Ir.c . Falls Church, Virginia
Dr. James M. Symons, Department of Civil and Environmental Engineering,
University of Houston. Houston, Texas
i
Dr. Vernon L. Snoeyink, Department of Civil Engineering, University of Illinois,
Urbana, Illinois
Dr. Rhodes Trussell, James M Montgomery Consulting Engineers, Inc., Pasadena,
California
Dr. James EL Watson, Department of Environmental Sciences and Engineering,
University of North Car..; ma. Chapel Hill, North Carolina
Invited T
Dr. Douglas Crawford Brown, University of North Carolina, Department of
Environmental Sciences and Engineering, Chapel Hill, North Carolina
Science Advisory Board Staff:
Dr. K. Jack Kooyoomjian, Designated Federal Official, U.S. EPA, Science Advisory
Board (A-101F), 401 M Street, SW, Washington, DC 20460
iv
-------
Mrs. Diana L. Pozun, Staff Secretary, U.S. EPA, Science Advisory Board
-------
TABLE OF CONTENTS
1. EXECUTIVE SUMMARY 1
1.1 Overview 1
1.2 Occurrence and Risk Estimates 2
1.3 Reasonableness of Cost Estimates For Mitigating Radon 4
1.4 The Technologies for Central or Well-Head Treatment and
Judgements on Best Available Technology 5
1.5 The Cost Estimates of Design, Operation Installation and
Maintenance of These Technologies for Each Size Range 5
2. INTRODUCTION 8
3. REGULATORY RATIONALE 10
4. OCCURRENCE AND RISK ESTIMATES 12
5. RESPONSES TO THE CHARGE 16
5.1 Response to Charge Question 1 16
5.2 Response to Charge Question 2 17
5.2.1 BAT Judgements 18
5.2.2 Appropriate Technologies For Each Size Range 18
5.3 Response to Charge Question 3 21
APPENDIX A REVIEW, BRIEFING AND BACKGROUND MATERIALS . A-l
APPENDIX B - LITERATURE CITED B-i
APPENDDC C - COST ESTIMATES AND UNCERTAINTY MEASURES ... C-l
APPENDIX D - GLOSSARY OF TERMS AND ACRONYMS D-l
VI
-------
1. EXECUTIVE SUMMARY
This report presents the Science Advisory Board's (SAB) review of the
Agency's approach to the costs of radon control or mitigation experienced by
households or communities. Our findings and recommendations are aimed at
improving the Agency's overall approach.
1.1 Overview
Radon in drinking water is a two-fold concern in environmental health. It
is a drinking water contaminant which can impact health through the ingestion
route as can many other contaminants regulated under the 1988 SDWA. It also
can contribute to indoor air radon concentrations which expose occupants through
inhalation. Both concerns need to be addressed by the Agency, but it should not
ignore the issue of whether a regulatory focus on waterborne radon will
significantly reduce the health risk posed by radon in comparison with other viable
approaches.
i
It is recognized that current statutes mandate that EPA regulate radon in
drinking water to reduce exposure to radon in homes, even though the
contribution of drinking water :o indoor air radon concentration is quite small
compared with radon from soil emission. But it is also recognized that radon
from water may yield potentially greater health impacts through the combined
inhalation and ingestion routes than other water contaminants which are
regulated by EPA.
The primary source of radon in indoor air is soil gas which produces .m
ambient outdoor air concentration of about 0.4 pCi/L^ , and an average indoor
concentration of abbut 1.3 pCi/L,^. EPA estimates that if all homes with
concentrations above 4 pCi/L^ were mitigated with present technology, th«in .\'.»• .t
-------
3,000 of the 13,500 yearly deaths attributed to indoor radon could be eliminated.
Under this scenario, the cost per life saved would be about $700,000.
The contribution of waterborne indoor radon is much smaller, and it is
estimated by EPA that there is a ratio of about 10,000 to 1 (one) between the
water concentration and the increase in the indoor air concentration, with typical
household water use. Therefore, 300 pCi/L in water contributes approximately
0.03 pCi/L^ to the indoor air concentration. The EPA estimates that from 81 to
89 deaths (depending on the model) could be avoided per year by reducing all
ground-based public water systems to 300 pCi/Lwater. The most recent cost
estimates are about $400M ($400,000,000) per year, or about $3.2M per life saved.
This wide discrepancy between the cost-effectiveness of mitigating water-
borne radon versus soil gas radon underscores the minor role that waterborne
radon plays in the overall indoor health hazard. Still, its regulation is required
under the Safe Drinking Water Act (SDWA).
The question addressed is: To what degree will regulation of radon in water
i
bring about a reduction in exposure, and risk, to airborne radon in homes, and has
the U.S. EPA shown that a focus on waterborne radon is reasonable and cost-
effective in light of this goal? The inclusion of non-inhalation pathways of
exposure, especially direct ingestion, does not significantly alter the conclusions
here. (NOTE: Estimates of exposure from direct ingestion were included in EPA's
analysis.)
1.2 Occurrence and' Risk Estimates
The occurrence data employed by the U.S. EPA in estimating exposures to
airborne radon are both the best available and a reasonable basis for making such
estimates-. The affected population was determined based on a properly random
-------
national survey of indoor radon in U.S. homes. The measurement technique
employed was alpha track detectors placed into homes for an entire year. While
new data continue to be produced, it is unlikely that these data will significantly
change the existing estimates of the distribution of airborne radon concentrations
in U.S. homes.
The contribution of waterborne radon to indoor air concentrations is less
well established. Current estimates are that a regulatory limit of 300 pCi/Lwater
would reduce the average U.S. concentration of waterborne radon to approximately
50% of the present value, indicating that regulation of waterborne radon at 300
pCi/Lwate would reduce the total risk of airborne radon by less than 0.5% from
the currently existing risk.
It should be noted that homes with very high concentrations of waterborne
radon may contain a higher contribution of airborne radon from water. A
waterborne radon concentration of 10,000 pCi/Lwater would yield an average
contribution of 1 pCi/L^, which is significant relative to the national average.
Homes utilizing water with high radon concentrations, however tend also to have
high airborne concentrations from subsoil sources. The U.S. EPA should develop
estimates of the distribution of airborne radon contributions from waterborne
radon both in the presence and in the absence of potential regulatory limits on
waterborne radon.
The airborne risk estimates used by EPA are based on recommendations of
the National Academy of Sciences's (NAS) Committee on the Biological Effects of
Ionizing Radiation (BEIR). These estimates are extrapolated from data obtained
from uranium miners, and a modifying factor has been added to account for
differences between exposure conditions and physiological properties of individuals
in mines and homes. Both the BEIR Committee and EPA have noted the
uncertainty in these estimates. The SAB's Radiation Advisory Committee (RAO
has reviewed this in the past and concurred with the EPA's risk estimates. These
-------
uncertainties in the risk estimates are reflected in the EPA's range of values for
the cost per life saved.
1.3 Reasonableness of Cost Estimates For Mitigating Radon
The Subcommittee determined that the EPA offices are employing a
reasonable framework for estimating the cost and cost-effectiveness of mitigating
airborne indoor radon in residences. The approach embodies standard Agency and
industry methodology, focuses on existing homes, considers inhalation as the only
exposure pathway and does not differentiate by radon source (i.e., soil versus
water). This approach includes the determination of the affected population,
determination of the cost for testing and mitigation, analysis of the risk reduction
from mitigation and calculation of the cost per life saved. The cost data for
testing of air and mitigation of subsoil sources are based on a substantial body of
data from actual practice and represent the consensus of a group of industry
experts.
In summary the Subcommittee considers the approach to be reasonable, and
the availability of the data from a national survey of indoor radon and actual cost
data strengthen the final result. The Subcommittee considers EPA's calculations
of cost per life saved to be based upon reasonable occurrence estimates, risk
estimates and cost estimates.
The Office of Groundwater and Drinking Water (OGW&DW) has
approached the development of the unit costs for the removal of radon from
drinking water by Packed Tower Stripping (PTS) in a reasonable manner.
Problems do arise in calculating the total unit costs, however, because of the
assumptions made on the individual items that make up the total unit costs.
Other water treatment authorities have made their own estimates, using nearly
the same approach as OGW&DW, and have estimated different total costs. The
SAB does not wish to comment on which is the "correct" assumption for each
-------
component of the total, but does recommend that OGW&DW meet with these
other groups and their consultants to understand and resolve these differences.
The impact of significant differences can be severe in terms of national costs to
implement a radon rule.
1.4 The Technologies for Central or Well-Head Treatment and Judgements on
Best Available Technology
Certainly aeration is an effective technique for removing radon from
groundwater and qualifies as BAT for central treatment. However, there may be a
piecemeal problem in using Packed Tower Aeration (PTA) in certain localities
because of off-gas dispersal. Granular Activated Carbon (GAG) was also discussed
as a possible BAT. EPA cited long contact times required and difficulties in
disposing of waste GAG as reasons for rejecting this technology. Yet, it seems
that GAG has been demonstrated to remove radon, .and that problems of waste
disposal may be manageable where influent radon levels are modest. Additionally,
GAC may be a particularly well-suited technology for small systems, since it could
be installed as an in-line pres.su rp vessel not requiring repumping. We
recommend that EPA review its choices for BAT, more carefully state the reasons
for its choices made and estimate the likely number of systems using GAC and the
attendant costs.
1.5 The Cost Estimates of IVsign, Operation Installation and Maintenance of
These Technologies for Kach Size Range
The basic approach the KPA is taking reflects a standard framework to cost
estimation: compiling and analyzing data on occurrence, determining the likely
technology to be used, and estimating the cost of technology implementation as a
function, of the water quality and system size. However, there are three concerns
that the SAB has about these estimates: a) the basic objective of the cost
-------
estimation process, b) the consideration of the relationship of system size, style
of design and operation, and c) whether the costs are appropriately estimated?
It is unclear whether EPA's purpose is to estimate the costs industry will
most likely incur as a result of the radon regulations or to estimate the lowest
possible cost industry could incur. There was extensive discussion on this point by
the Subcommittee at its review meeting of February 8, 1993. In either case, EPA
would do well to invite more direct interaction with various commenters to obtain
better data on actual construction, operation, and cost estimating practice before
making its independent judgements.
With regard to consideration of alternative aeration technologies at different
sizes: EPA's estimates are based on the use of a PTA for all system sizes.
Operation and Maintenance (O&M) costs are also based on a uniform approach for
all sizes. Actual practice is likely to vary with the size of the system installing the
treatment. Some experience might be gained from the volatile organic carbon
(VOC) rule here. Very small systems are likely to experiment with a variety of
their own informal designs as well as a variety of packaged systems and their
style of operation and interface with the public and with regulatory agencies is
likely to be more informal as well. Larger systems are likely to impose a more
formal design, bid, and construction practice and experience closer regulatory
review and greater public input. If EPA's purpose is to produce an estimate
reflecting the most likely cost, then these estimates should better reflect the
impact of system size on design practice.
Interest rate assumptions markedly impact the annualized capital costs for
radon removal from drinking water. O&M costs are insensitive to interest rates.
Capital improvements for many small systems require interest rates of 10% or
higher. Annual costs for radon removal by PTA were based on a three percent
interest rate. The impact of a 10 percent interest was also evaluated, but the
emphasis was on a three percent interest rate. The SAB recommends that an
-------
interest rate higher than the 3% currently employed by the Agency be used. The
cost of disinfection resulting from radon PTA treatment is a significant factor in
the cost of radon mitigation and should be explicitly stated for different size
systems. Groundwater can be distributed without disinfection only if the system
has appropriate barriers to contamination by micro-organisms. Also, the cancer
risks associated with exposures to disinfection by-products were not discussed.
It would be most helpful to members of Congress, the states, various water
treatment authorities and the interested public to have the Agency's presentation
and summary of data, as well as the Agency's recommendations succinctly
presented in the report to Congress in a few well-planned and clearly labeled
summary tables, histograms or charts. This will serve to focus the many issues
onto the key recommendations of the Agency, and to obtain a summary of the
- trade-offs involved with this issue.
Finally, the SAB recommends that the OGW&DW participate in the
upcoming "Radon Removal by Packed Tower Stripping" American Water Works
Association (AWWA) research project so that they can have their input on project
design and data collection. This will make the output of this important study as
useful to OGW&DW as possible.
In summary, the SAB is pleased that the OGW&DW has recalculated their
unit costs for PTA in response to the comments already received and the SAB
recommends that they continue this iterative process with the commenters and
work cooperatively with other responsible interested parties.
-------
2. INTRODUCTION
At the request of the Office of Drinking Water (ORD), the Radon
Engineering Cost Subcommittee (REGS) of the Science Advisory Board's (SAB)
Drinking Water Committee (DWC) met on February 8 and 9, 1993 to review
background reports and documents related to the cost of mitigating indoor radon.
(See Appendix A - References 1-6, 10-13, and 15). The Subcommittee was made
up of members of the DWC, the Radiation Advisory Committee (RAG), and the
Environmental Engineering Committee (EEC). Presentations by EPA staff (J.W.
Conlon, F. Marcinowski, M.J. Parrotta, M. Cummins, JA Auerbach, and others.
See Appendix A - Reference 11.) were also heard by the Subcommittee.
The statement of charge to the Subcommittee, as accepted by the
Subcommittee, was as follows:
a) To determine whether the EPA is employing a reasonable approach
for estimating the coat of mitigating indoor radon from drinking
water in residence.
b) To assess whether the EPA has made appropriate judgements of Best
Available Techno!.»y iBAT) for central of well-head treatment of each
size water treatment facility category, and whether the cost estimates
of design, operation installation and maintenance of these
technologies are accurately estimated; and
8
-------
c) To address the relative cost-effectiveness of controlling radon
exposure from drinking water in comparison to controlling other
sources of indoor radon.
Each of the three elements of the charge are addressed below.
i ^'Effective" in this context means the extent to which radon exposure is reduced
by the treatment applied to produce significant improvements in health.
-------
3. REGULATORY RATIONALE
The history of concern over radon in water (See, for instance, Appendix B -
References 1-3, 5, and 7-9) provides the framework within which the following
discussion must be placed. That history is that (a) radon was found to be a source
of risk in mining populations exposed to airborne radon, (b) airborne radon was
found in indoor air of homes, (c) radon was found in water supplies in the U.S.,
and (d) radon was found to emanate from water to air in homes. It was
concluded that waterborne radon might pose a potential risk to human health
through its contribution to the concentration of airborne radon in homes (See, for
instance, Appendix B, Reference 5).
Subsequent risk analyses performed by the U.S. EPA and others indicated
that emanation from water to air is not the only route of exposure to waterborne
radon (See, for instance, Appendix B, References 7-9), direct ingestion also being of
potential significance based on calculation, the historical focus on airborne radon
remains. Even if ingestion exposures are considered, the conclusions of this report
are not altered. This raises the issue of whether a regulatory focus on waterborne
radon will significantly affect the health risk posed by radon in the general
environment. The present section examines the three goals of any potential radon
policy.
The first goal is to reduce the risk from waterborne pollutants. This goal
requires an answer to the question of whether waterborne radon produces a
significant additive risk and whether a focus on waterborne radon, rather than on
other pollutants, is a reasonable means for reaching a significant reduction in
health risk. The second goal might be to reduce the risk from environmental
radon. This" requires an answer to the question of whether environmental radon
produces a significant risk and whether a focus on waterborne radon will
reasonably reduce the overall risk posed by environmental radon. The third goal
10
-------
might be to reduce the overall environmental risk from all sources of risk. The
question to be addressed here is whether a focus on environmental radon will be
the most effective means to reach this goal (See, for instance, Appendix B,
References 4 & 6 pertaining to reducing risk).
The following discussion focuses only on the second policy goal. The
question addressed is: To what degree will regulation of radon in water bring
about a reduction in exposure, and risk, to airborne radon in homes, and has the
U.S. EPA shown that a focus on waterborne radon is reasonable and cost-effective
in light of this goal? It is presumed that inclusion of non-inhalation pathways of
exposure, especially direct ingestion, does not significantly alter the conclusions
here.
11
-------
4. OCCURRENCE AND RISK ESTIMATES
The occurrence data employed by the U.S. EPA in estimating exposures to
airborne radon are both the best available and a reasonable basis for making such
estimates. The affected population was determined based on a random national
survey of indoor radon in U.S. homes. The measurement technique employed was
alpha track detectors placed into homes for a year. While new data continue to
be produced, it is unlikely that these data will significantly change the existing
estimates of the distribution of airborne radon concentrations in U.S. homes.
The contribution of waterborne radon to indoor air concentrations is less
well established for two reasons. First, the occurrence data on waterborne radon
continue to be weakened by considerations of sample size and conflicting sets of
data. Second, the equilibrium ratio between airborne radon concentration (as
produced by only waterborne radon) and the waterborne radon concentration is
not well established. At present, the estimate of 1 per 10,000 for this ratio as
adopted by the U.S. EPA is reasonable in light of the existing data but must be
viewed as preliminary. An equilibrium ratio of 1 per 10,000 is assumed in this
discussion.
The average concentration of radon in potentially regulated U.S. water
supplies is estimated by EPA to be approximately 300 pCi/Lvrater in groundwater
systems (100 pCi/Lwater when considering a population-weighted average of ground
and surface water systems). EPA estimates that a 300 pCi/Lwater standard would
reduce total risk from radon by approximately 2.5% (See Appendix B - references
11 and 12, as well as memo dated 4/20/93 from Douglas Crawford-Brown, which
includes relevant citations.) Assuming an equilibrium ratio of 10,000 to 1, water
to household air, the average contribution to airborne radon from waterborne
radon is estimated to be 0.01 pCi/L^. This contrasts with an average indoor
airborne radon concentration of between 1 and 1.5 pCi/L for all sources of
12
-------
airborne radon. Regulation of waterborne radon then will reduce the total
airborne radon risk (all sources of radon considered) by less than 1%. By
whatever route one arrives at the calculation of total risk from radon, that is
whether it is 0.5% or 2.5%, it most assuredly is a small risk level compared to soil
gas radon.
This contribution to the total reduction of risk (1%) is lessened by the fact
that a regulatory limit on waterborne radon would reduce, not remove radon from
all water supplies. Current estimates are that a regulatory limit of 300 pCi/Lvnter
would reduce the average U.S. concentration of waterborne radon to approximately
50% of the present value, indicating that regulation of waterborne radon at 300
pCi/Lwater would reduce the total risk of airborne radon by less than 0.5% from
the currently existing risk.
It should be noted that homes with very high concentrations of waterborne
radon may contain a higher contribution of airborne radon from radon emanated
by water. A waterborne radon concentration of 10,000 pCi/Lwater would yield an
average contribution of 1 pCi/Lair, which is significant relative to the national
average., Homes utilizing water with high radon concentrations, however tend also
to have high airborne concentrations from other sources. The U.S. EPA should
develop estimates of the distribution of airborne radon contributions from
waterborne radon both in the presence and in the absence of potential regulatory
limits on waterborne radon.
The risk estimates used by EPA are based on recommendations of the
NAS's Committee on the Biological Effects of Ionizing Radiation (BEIR). These
estimates are extrapolated from data obtained from uranium miners, and a
modifying factor has been added to account for differences between exposure
conditions and physiological properties of individuals in mines and homes. Both
the BEIR Committee and EPA have noted the uncertainty in these estimates. The
SAB's Radiation Advisory Committee (RAO has reviewed and concurred with the
13
-------
EPA's risk estimates. These uncertainties are in the risk estimates are reflected
in the EPA's range of values for the cost per life saved.
The Subcommittee notes that two major points related to epidemiology that
were not covered in the meeting. First, the miner risk data is for exposures
considerably higher than the 4 pCi/L^ action level recommended for homes, and
the linear extrapolation to 4 pCi/L^ has been the subject of controversy in the
past. In the case of the very small incremental change in radon levels from water
contributions (0.03 from 300 pCi/L^^, there is some question as to its effect if
the initial house levels are also very low (e.g., house at 0.5 pCi/L^ and water
contribution of 0.03 pCi/L^ results in a net 0.53 pCi/L^p. The linear
extrapolation becomes even more questionable at the low levels. Second, the risk
.to non-smokers is at least a factor of 10 lower than the risk to smokers.
The Subcommittee determined that the EPA offices are employing a
reasonable framework for estimating the cost and cost-effectiveness of mitigating
airborne indoor radon in residences. The approach embodies standard Agency and
industry methodology, focuses on existing homes, considers inhalation as the only
exposure 'pathway and does not differentiate by radon source (i.e., soil versus
water). The cost data for testing and mitigation of radon in indoor air are based
on a substantial body of data from actual practice and represent the consensus of
industry experts.
The national costs for testing and mitigation are based on an action level of
4 pCi/L^ and a mitigation reduction level of 2 pCi/L^. (The action, level
corresponds to 224 Lung Cancer Deaths (LCDs) per million). The national radon
mitigation costs are based on the summed weighted costs for installation, O&M for
various mitigation methods and foundation types.
In summary the Subcommittee considers EPA's calculations of cost per life
saved appear to be based upon reasonable occurrence estimates, risk estimates and
14
-------
cost estimates; however, much of these data are in a continuing state of evolution
and refinement.
15
-------
5. RESPONSES TO THE CHARGE
5.1 Response to Charge Question 1
Charge 1: To determine whether EPA is employing a reasonable approach
for estimating the cost of mitigating indoor radon from ambient and
drinking water sources in residences.
The Subcommittee determined that the EPA offices are employing a
reasonable approach for estimating the cost-effectiveness of mitigating airborne
indoor radon in residences. The approach embodies standard Agency and industry
methodology, focuses on existing homes, considers inhalation as the only exposure
pathway and does not differentiate by radon source (i.e., soil versus water) in its
occurrence estimates. This approach includes the determination of the affected
population, determination of the cost for testing and mitigation, analysis of the
risk reduction from mitigation and calculation of the cost per life saved.
The affected population was determined based on a national survey of
indoor radon in U.S. homes! The survey was conducted using alpha track
detectors which were placed in homes for a full year. Cost data for testing and
mitigation are based on a substantial body of data from actual practice. The risk
estimates used by EPA are based on recommendations of the National Academy of
Science's Committee on the Biological Effects of Ionizing Radiation (BEIR). These
estimates are extrapolated from data obtained from uranium miners, and a
modifying factor has been added to account for differences between exposure
conditions and physiological properties of individuals in mines and homes. Both
the BEIR Committee and the EPA have noted the uncertainty of these estimates.
The SAB's Radiation Advisory Committee has reviewed and concurred with the
EPA's risk estimates. In addition to the uncertainty in the risk estimates, there
are other uncertainties that are reflected in the EPA's range of values for the cost
per life saved. In summary, the Subcommittee considers the approach to be
16
-------
reasonable, and the availability of the data from a national survey of indoor radon
and actual cost data support the Agency's final result.
The contribution of waterborne radon to indoor air concentrations is less
well established for two reasons. First, the occurrence data on waterborne radon
continue to be weakened by considerations of sample size and conflicting sets of
data. Second, the equilibrium ratio between, airborne radon concentration (as
produced by only waterborne radon) and the waterborne radon concentration is
not well established. At present, the estimate of 1 per 10,000 for this ratio as
adopted by the U.S. EPA is reasonable in light of the existing data but must be
viewed as preliminary. An equilibrium ratio of 1 per 10,000 is assumed in this
discussion.
The average concentration of radon in potentially regulated U.S. water
supplies is approximately 300 pCi/Lwater in groundwater systems (100 pCi/Lwater
when considering a population-weighted average of ground and surface water
systems). EPA estimates that a 300 pCi/Lwater standard would reduce total risk
from radon by approximately 2.5%. (See Appendix B - references 11 and 12, as
well as memo dated 4/20/93 from Douglas Crawford-Brown, which includes
relevant citations.) Assuming an equilibrium ratio of 10,000 to 1, water to
household air, the average contribution to airborne radon from waterborne radon
is estimated to be 0.01 pCi/L^. This contrasts with an average indoor airborne
radon concentration of between 1 and 1.5 pCi/L^ for all sources of airborne
radon. Regulation of waterborne radon then will reduce the total airborne radon
risk (all sources of radon considered) by less than 1%. By whatever route one
arrives at the calculation of total risk from radon, that is whether ft is 0.5% or
2.5%, it most assuredly is a small risk level compared to soil gas radon.
5.2 Response to Charge Question 2
17
-------
Charge 2: To assess whether the EPA has made appropriate judgements of
Best Available Technology [BAT] for central or well-head treatment of each
size water treatment-facility category, and whether the cost estimates of
design, operation installation and maintenance of these technologies, are
accurately estimated.
The question of BAT will be discussed in two parts: 1) Are EPA's BAT
Judgments appropriate?, and 2) Are appropriate technologies selected for each size
range?
5.2.1 BAT Judgements
Certainly aeration is an effective technique for removing radon from
groundwater and qualifies as BAT. Granular Activated Carbon (GAC) was also
discussed as a possible BAT. EPA cited long contact times required and
difficulties in disposing of waste GAC as reasons for rejecting this technology. Yet
is seems that GAC has been demonstrated to remove radon, and that problems of
waste disposal may be manageable where influent radon levels are modest.
Moreover, GAC may be a part:c-_:arly important technology for small systems,
because the units would be small, regardless of the longer contact time, and more
importantly, can be applied a* i pressure vessel not requiring repumping.
Moreover there may also be a pr-jblem in using Packed Tower Aeration (PTA) in
certain localities because of oif m dispersal and the cost of repumping.
Additional community aesthetic concerns deal with the unsightly character of air
towers. We recommend that EPA reconsider its choices for BAT and more
carefully state the reasons for its choices made, as well as estimate the likely
number of systems using GAC and the attendant costs.
5.2.2 Appropriate Technologies For Each Size Range
18
-------
There are three concerns that the SAB has about these estimates: a) the
basic objective of the cost estimation process, b) the consideration of the
relationship of system size style of design and operation, and c) are the costs
appropriately estimated?
a) Basic objectives; It is unclear whether EPA's purpose is to estimate
the costs industry will most likely incur as a result of the radon
regulations or to estimate the lowest possible cost industry could
incur. There was extensive discussion on this point by the
Subcommittee at its review meeting of February 8, 1993. In either
case, EPA would do well to invite more direct interaction with
various commenters to obtain better data on actual construction,
operation, and cost estimating practice before making its independent
judgements.
b) Consideration of alternative aeration technologies at different sizes:
EPA's estimates are based on the use of PTA for all system sizes.
O&M costs are also based on a uniform approach for all sizes. Actual
practice is likely to vary with the size of the system installing the
treatment. Some experience might be gained from the VOC rule here.
Very small systems are likely to experiment with a variety of their
own informal designs as well as a variety of packaged systems and
their style of operation and interface with the public and with
regulatory agencies is likely to be more informal as well. Again, GAG
may be a particularly well-suited technology for small systems, since
it could be installed as an in-line pressure vessel not requiring
repumping. Larger systems are likely to impose a more formal
design, bid, and construction practice and experience closer regulatory
review and greater public input. Larger systems also often have
wells in residential areas and are required by local planning boards to
design the facility to blend in with the surrounding homes. These
19
-------
requirements significantly increases costs. If EPA's purpose is to
produce an estimate reflecting the most likely cost, then these
estimates should better reflect the impact of system size on design
practice.
c) Costs Appropriately Estimated: The basic approach the EPA is
taking to cost estimation, that is, compiling and analyzing data on
occurrence, determining the likely technology to be used, and
estimating the cost of technology implementation as a function of the
water quality and system size are appropriate.
d) Additional Considerations: (Refer to Appendix C - Tables of Cost
Estimates and Uncertainty Measures.)
(1) The EPA analysis was of drinking water mitigation, and only
considered the cost per life saved for an aggregation of all sizes of
central water systems, but this data can be used to determine the cost
per life saved for each system size category. When this is done, the
largest systems show a cost of less than $500,000 per life saved, and
the smallest systems .show a cost of over $50M per life saved. This
disaggregation su^v.sts that central system mitigation mav not be
economical for th<» smaller systems. Continuing this line of analysis,
systems with very high radon concentrations might be analyzed
separately, and PTA might be shown to be cost-effective (e.g., a small
system with 30,000 pCi/Lwater rather than the assumed 300
pCi/Lwater would have a cost-effectiveness of about $500,000 per life
saved).. The Subcommittee recommends that the EPA use this type of
disaggregated analysis.
(2) If central water system mitigation is not cost-effective for some
systems, then other non-central radon mitigation technologies rr.-.ijht
20
-------
be investigated so that mitigation advice or assistance can be provided
to the public at risk. From the EPA analysis of air and water
mitigation, the effectiveness of installing a standard soil gas radon
mitigation system in-house with water radon problems can be
estimated. Assuming a background of 0.4 pCi/L^, an average house
level of 1.3 pCi/L^, and a mitigation system effectiveness of 50%,
radon levels could be lowered OA5pCi/L^r for a cost of about $185
per year. The cost per life saved is about $1.2M per year. The
Subcommittee recommends that the EPA use this type of analysis to
investigate the cost of standard soil gas mitigation as an alternative
to central system treatment.
(3) In the small central water systems, where central radon
mitigation might not be cost-effective, there may be very simple non-
central system mitigation systems that would provide even more cost-
effective mitigation than the standard Active Sub-Slab
Depressurization (ASD) systems (for soil gas mitigation). For
instance, entry from washing clothes or showering might be mitigated
with exhaust fans, and drinking water might be filtered with a very
small GAG system The Subcommittee recommends that the EPA
study new types of low cost mitigation alternatives and perform
research if necessary.
5.3 Response to Charge Question 3
Charge 3: To address the relative cost-effectiveness^ of controlling radon
exposure from drinking water in comparison to controlling other sources of
indoor radon.
V ji». ——
Effective" in this context means the extent to which radon exposure ;s .'•••:
by the treatment applied to produce significant improvements in health.
21
-------
Radon in drinking water is a two-fold concern in environmental health. It
is a drinking water contaminant which can impact health through the ingestion
route as can many other contaminants regulated under the 1988 SDWA. It also
can contribute to indoor air radon concentrations which expose occupants through
inhalation. Both concerns need to be addressed by the Agency.
The SAB review of the EPA approach to evaluation of the overall indoor
airborne radon exposure and its mitigation cost-effectiveness has been discussed
above under Charge 1. The cost-effectiveness of mitigation of radon in water in
comparison to controlling other sources of indoor radon is discussed here.
It is recognized that current statutes mandate that EPA regulate radon in
drinking water to reduce exposure to radon in homes, even though the
contribution of drinking water to indoor air concentration is quite small compared
with radon from soil emission. But it is also recognized that radon from water
yields potentially greater health impacts through the combined inhalation and
ingestion routes than do the concentration of many other water contaminants
which are regulated by EPA.
The primary source of radon in indoor air is soil gas which produces an
ambient outdoor air concentration of about 0.4 pCi/L^, and an average indoor
concentration of about 1.3 pCi/L^. EPA estimates that if all homes with
concentrations above 4 pCi/L^ were mitigated with present technology, then about
3,000 of the 13,500 yearly deaths attributed to indoor radon could be eliminated.
Under this scenario* the cost per life saved would be about $700k.
The contribution of waterborne indoor radon is much smaller, and it is
estimated that there is a ratio of about 10,000 to (1) one between the water
concentration and the increase in the indoor air concentration, with typical
household water use. Therefore, 300 pCi/Lwater in water contributes
approximately 0.03 pCi/L^ to the indoor air concentration. The EPA estimates
22
-------
that approximately 80 deaths could be avoided per year by reducing all ground-
based public water systems to 300 pCi/Lwater. The most recent cost estimates are
about $400M per year, or about $3.2M per life saved.
This wide discrepancy between the cost-effectiveness of mitigating
waterborne radon versus soil gas radon underscores the minor role that
waterborne radon plays in the overall indoor health hazard. Still, its regulation is
required under the SDWA. This regulatory policy, however, should not negate the
logic and practical considerations that relate to determining U.S. cost burdens.
The Office of Groundwater and Drinking Water (OGW&DW) has
approached the development of the unit costs for the removal of radon from
drinking water by PTS in a reasonable manner. Problems do arise in calculating
the total unit costs, however, because of the assumptions made on the individual
items that make up the total unit costs. Other thoughtful groups have made their
own estimates, using nearly the same approach as OGW&DW, and have estimated
different total costs.
i
The SAB does not wish to comment on which is the "correct" assumption
for each component of the total, but does recommend that OGW&DW meet with
these other groups and their consultants to understand these differences. The
result of these meetings probably will be a range of costs, the low end being a
"bare bones" system that smaller systems might install, the high end being a
"engineered" system that a larger system might install. This result would have
two advantages; one, the assumptions supporting the cost for each system would
be clearly delineated and two, OGW&DW would have a better understanding of
the expected range of costs around their estimate of "best", rather than the
assumed 20 percent lower and 30 percent higher that is now being used.
One important part of the OGW&DW's calculation on which the SAB
want to comment specifically is that of the interest rate assumptions used.
23
-------
Interest rate assumptions markedly impact the annualized capital costs for radon
removal from drinking water. O&M costs are insensitive to interest rates.
Capital improvements for many small systems require interest rates of 10% or
higher. Annual costs for radon removal by Packed Tower Aeration (PTA) were
based on a three percent interest rate. The impact of a 10 percent interest was
also evaluated, but the emphasis was on a three percent interest rate. The SAB
recommends that an Interest rate higher than the 3% currently employed by the
Agency be used.
The cost of disinfection resulting from radon PTA treatment is a
significant factor in radon cost mitigation and should be explicitly stated for
different size systems. Systems that require PTA, which are not now disinfected,
will require disinfection. Groundwater can be distributed without disinfection only
if the system has appropriate barriers to contamination by microorganisms. PTA
introduces the possibility of such contamination, and, thus, disinfection is required.
The cost of such disinfection has not been explicitly itemized in the cost of radon
control, and the SAB recommends that this oversight be corrected. The
Subcommittee understands, based on subsequent discussions with OGW&DW staff,
that the 'cost of disinfection varies considerably based on system size. For
instance, predominantly small systems have costs for disinfection ranging typically
from $100 to $200/year/household, while large systems may only cost a few dollars
per household per year. It is the Subcommittee's view that costs of disinfection,
especially in small systems, needs to be reviewed thoroughly.
In summary, the SAB is pleased that the OGW&DW has recalculated their
unit costs for PTA in response to the comments already received and the SAB ;
recommends that they continue this iterative process with the commenters and
works cooperatively with other responsible interested parties.
Finally, the SAB recommends that the OGW&DW participate in the
upcoming. "Radon Removal by Packed Tower Stripping" American Water Works
24
-------
Association research project so that they can have their input on project design
and data collection and consider the new AWWA and ACWA documents in their
future review. This will make the output of this important study as useful to
OGW&DW as possible.
Currently, the EPA has considered PTA as the only feasible BAT. However,
the Subcommittee.considers that treatment with GAG should be revisited,
especially since it would enable a system to use it as an in-line pressure vessel, not
requiring repumping. It could also eliminate the need for disinfection.
25
-------
APPENDIX A
REVIEW, BRIEFING AND BACKGROUND MATERIALS
1) Cummins, Michael D., Memorandum to Marc. Parrotta, entitled "Removal
from Contaminated Ground Water by Packed Column Air Stripping, " U.S.
EPA, Water Supply Technology Branch, Cincinnati, Ohio, April 26, 1988
2) Cummins, Michael D., Memorandum to Marc Parrotta entitled "Packed
Tower Aeration Cost Estimates for Radon Removal," U.S. EPA, Office of
Ground Water and Drinking Water, Technical Support Division, March 11,
1992
3) Longtin, Jon (Project Engineer, TSD) and Denning, George (Economist,
OPD&E), "Draft for Discussion with QAMS of the Data Quality Objectives
for the National Inorganics and Radionuclides Survey," Technical Support
Division, Office of Drinking Water, Office of Water, U.S. EPA, Cincinnati,
Ohio, March 8, 1985
4) Mills, William R., Stephen K. Hall and Thomas E. Levy, Letter to Carol M.
Browner, Raymond C. Loehr, Genevieve Matanoski, and Verne Ray from the
Alliance for Radon Reduction, February 2, 1993
5) Cummins, Michael D. Memorandum to Marc Parrotta entitled "Simplified
Equations for Estimating Radon Removal Cost via Packed Tower Aeration,"
U.S. EPA, Office of Ground Water and Drinking Water, Technical Support
Division, July 16, 1992
6) Parrotta, Marc, Memorandum to Addressees entitled "Cost Modeling
Update," U.S. EPA, Office of Water, February 21, 1992
7) Saum, David, Memorandum to Members of the SAB Radon Engineering
Cost Subcommittee, dated February 3, 1993
8) Sullivan, John H., Letter to Carol Browner Pertaining to National Primary
Drinking Water Regulations: Radionuclides (Radon) [WH-FRL 3956-4], from
the Government Affairs Office of the American Water Works Association,
January 26, 1993
9) U.S. Congressional Record - Senate, S15103, Sec. 591 SAFE DRINKING
WATER ACT IMPLEMENTATION, September 25, 1992
10) U.S. EPA, "Addendum to The Occurrence and Exposure Assessments for
Radon, Radium-226, Radium-228, Uranium and Gross Alpha Particle
Activity in Public Drinking Water Supplies, " (Revised Occurrence Estimates
A-l
-------
Based on Comments to the Proposed Radionuclides regulation), A Draft
Document Prepared by Wade Miller Associates, Inc. under EPA Contract
No. 68-CO-0069, Work Assignment 1-32, for the Office of Ground Water and
Drinking Water, September 30, 1992
11) U.S. EPA, Briefing Materials by Dr. Janet A. Auerbach, Mr. James M.
Conlon, Mr. Michael Cummins, Mr. Frank Marcinowski, and Mr. Marc J.
Parrotta, February 8, 1993
12) U.S. EPA, "National Primary Drinking Water Regulations; Radionuclides;
Proposed Rule, 40 CFR Parts 141 and 142," Federal Register. Vol. 56, No.
138, pages 33050 to 33127, July 18, 1991 (Attention to the cost components
in the Table of Contents, Section V, where the mitigation technologies and
the costs are discussed.)
13) U.S. EPA, "Regulatory Impact Analysis of Proposed National Primary
Drinking Water Regulations for Radionuclides," Prepared by Wade Miller
Associates, Inc. under EPA Contract No. 68-CO-0069, Work Assignment No.
0-1 for the Office of Drinking Water, Washington, D.C., July 17, 1991
14) U.S. EPA, "Technical Support Document for the 1992 Citizen's Guide to
Radon," Office of Air and Radiation (ANR-464), EPA 400-R-92-011, May 20,
1992
15) U.S. EPA, "Technologies and Costs for the Removal of radionuclides from
Potable Water Supplies," Prepared by Malcom Pirnie, Inc. for the Drinking
Water Technology Branch, Office of Ground Water and Drinking Water,
July 1992 (NOTE: This is the primary review document.)
A-2
-------
APPENDIX B - LITERATURE CITED
1) Safe Drinking Water Act Amendments of 1986, Public Law 99-339, 100
STAT 642
2) Departments of Veterans Affairs and Housing and Urban Development, and
Independent Agencies Appropriation Act, 1993, PUB. L. 102-398, Section
519, 106 STAT 1618 (1992) (This is the citation adopted from the
Congressional Record (See Reference #3, below) that requires the EPA
Study of Radon.)
3) U.S. Congressional Record - Senate, S15103, Sec. 591 SAFE DRINKING
WATER ACT IMPLEMENTATION, September 25, 1992
4) U.S. EPA, "Safeguarding the Future; Credible Science, Credible Decisions,"
The Report of the Expert Panel on the Role of Science at EPA, [Panel
members are Raymond C. Loehr, Chairman, Bernard D. Goldstein, Anil
Nerode and Paul G. Risser], EPA/600/9-91/050, January 8, 1992
5) U.S. EPA, "Technical Support Document for the 1992 Citizen's Guide to
Radon," Office of Air and Radiation (ANR-464), EPA 400-R-92-011, May 20,
1992
6) U.S. EPA/SAB, "Reducing Risk: Setting Priorities and Strategies for
Environmental Protection. SAB-EC-90-021, September 25, 1990
7) U.S. EPA/SAB, "Review of the Office of Drinking Water's Assessment of
Radionuclides in Drink:r.^ Water and Four Draft Criteria Documents: Man-
Made Radionuclide Occurrence, Uranium, Radium, Radon," Prepared by the
Drinking Water Subcorr.m;::ee of the Radiation Advisory Committee of the
Science Advisory Board. KPA-SAB-RAC-87-035, July 27, 1987
8) U.S. EPA/SAB, "Status .1 Radionuclide Models," Prepared by the Radiation
Advisory Committee of the Science Advisory Board, EPA-SAB-RAC-92-001,
January 9, 1992
9) U.S. EPA/SAB, "Revised Radon Risk Estimates and Associated
Uncertainties," Prepared by the Radiation Advisory Committee of the
Science Advisory Board. EPA-SAB-RAC-LTR-92-003, January 9, 1992
B-l
-------
10) U.S. EPA/SAB, "Review of Draft Criteria Documents for Radionuclides in
Drinking Water," [Drinking Water Criteria Document for Uranium,
November 1989; External Review Draft for the Quantification of
Toxicological Effects Document on Radium, (TR-1242-67), 10 July 1990;
Quantitative Risk Assessment for radon in Drinking Water, May 1990; and
Quantitative Risk Assessment for Beta Particle and Gamma Emitters in
Drinking Water, May 1990], Prepared by the Radionuclides in Drinking
Water Subcommittee of the Radiation Advisory Committee of the Science
Advisory Board, EPA-SAB-RAC-92-009, January 9, 1992
11) Longtin, Jon "Occurrence of Radionuclides in Drinking Water: A National
Study," p. 97 Radon. Radium and Uranium in Drinking Water, edited by C.
Cothern and P. Rebers, Lewis Publishers, Cheslea, Michigan, 1990
12) Milvy, P. and C. Cothern, "Scientific Background for the Development of
regulations for Radionuclides in Drinking Water," p. 1 Radon. RJadium and
Uranium in Drinking Water, edited by C. Cothern and P. Rebers, Lewis
Publishers, Cheslea, Michigan, 1990
B-2
-------
APPENDIX C - COST ESTIMATES AND UNCERTAINTY
MEASURES
NOTE: The following tables of cost estimates and uncertainty measures, which
dissaggregate totals to include soil gas mitigation, have been provided by an
SAB/RECS consultant for illustration, comparison and discussion purposes only
and are not quality-checked or peer-reviewed for accuracy.
C-l
-------
DISTRIBUTION LIST
Deputy Administrator
Assistant Administrators
EPA Regional Administrators
EPA Laboratory Directors
Deputy Assistant Administrator for Office of Research and Development (ORD):
Director, Center for Environmental Research Information (CERI)
Director, Office of Environmental Engineering and Technology
Demonstration (OEETD)
Director, Office of Environmental Processes and Effects Research (OEPER)
Director, Office of Modeling, Monitoring Systems, and Quality Assurance
(OMMSQA)
Director, Office of Technology Transfer and Regulatory Support (OTTRS)
Deputy Assistant Administrator for Water:
Director, Office of Ground Water and Drinking Water (OGW&DW)
Director, Office of Science and Technology (OST)
Deputy Director, OST
Deputy Assistant Administrator for Air and Radiation:
Director, Office of Radiation and Indoor Air (ORIA)
Director, Office of Air Quality Planning and Standards (OAQPS)
Director, Office of Radiation Programs (ORP), Las Vegas, Nevada
Deputy Assistant Administrator for Office of Prevention, Pesticides and Toxic
Substances (OPPTS):
Director, Office of Pollution prevention and Toxics (OPPT)
Deputy Assistant Administrator for Office of Solid Waste and Emergency Response
(OSWER):
Director, Office of Emergency and Remedial Response (OERR)
Deputy Director, OERR
Director, Office of Solid Waste (OSW)
Deputy Director, OSW
Director, Technology Innovation office (TIO)
EPA Headquarters Library
EPA Regional Libraries
EPA Laboratory Libraries
-------
APPENDIX D - GLOSSARY OF TERMS AND ACRONYMS
ACWA
ASD
AWWA
BAT
BEIR
DWG
EEC
EHC
EPA
GAG
k
NAS
O&M
OGW&DW
ORD
PTA
PTS
L
LCD
M
ASSOCIATION OF CALIFORNIA WATER AGENCIES
ACTIVE SUB-SLAB DEPRESSURIZATION
AMERICAN WATER WORKS ASSOCIATION
BEST AVAILABLE TECHNOLOGY
BIOLOGICAL EFFECTS OF IONIZING RADIATION
DRINKING WATER COMMITTEE (U.S. EPA/SAB)
ENVIRONMENTAL ENGINEERING COMMITTEE (U.S. EPA/SAB)
ENVIRONMENTAL HEALTH COMMITTEE (U.S. EPA/SAB)
U.S. ENVIRONMENTAL PROTECTION AGENCY (U.S. EPA, or
"The Agency")
GRANULAR ACTIVATED CARBON
THOUSAND (DOLLARS)
NATIONAL ACADEMY OF SCIENCE
OPERATION AND MAINTENANCE
OFFICE OF GROUNDWATER AND DRINKING WATER
OFFICE OF RESEARCH AND DEVELOPMENT, U.S. EPA
PACKED TOWER AERATION
PACKED TOWER STRIPPING
LITER
LUNG CANCER DEATHS
MILLION (DOLLARS)
PICO CURIE
pCi
pCi/Lwater Concentration in water
pCi/L^ Concentration in air
RAG RADIATION ADVISORY COMMITTEE (U.S. EPA/SAB)
SAB SCIENCE ADVISORY BOARD (U.S. EPA)
SDWA SAFE DRINKING WATER ACT OF 1988
U.S. UNITED STATES
VOC VOLATILE ORGANIC CARBON
D-l
-------
DISTRIBUTION LIST
Deputy Administrator
Assistant Administrators
EPA Regional Administrators
EPA Laboratory Directors
Deputy Assistant Administrator for Office of Research and Development (ORD):
Director, Center for Environmental Research Information (CERI)
Director, Office of Environmental Engineering and Technology
Demonstration (OEETD)
Director, Office of Environmental Processes and Effects Research (OEPER)
Director, Office of Modeling, Monitoring Systems, and Quality Assurance
(OMMSQA)
Director, Office of Technology Transfer and Regulatory Support (OTTRS)
Deputy Assistant Administrator for Water:
Director, Office of Ground Water and Drinking Water (OGW&DW)
Director, Office of Science and Technology (OST)
Deputy Director, OST
Deputy Assistant Administrator for Air and Radiation:
Director, Office of Radiation and Indoor Air (ORLA)
Director, Office of Air Quality Planning and Standards (OAQPS)
Director, Office of Radiation Programs (ORP), Las Vegas, Nevada
Deputy Assistant Administrator for Office of Prevention, Pesticides and Toxic
Substances :OPPTS):
Director, Office of Pollution prevention and Toxics (OPPT)
Deputy Assistant Administrator for Office of Solid Waste and Emergency Response
(OSWER):
Director, Office of Emergency and Remedial Response (OERR)
Deputy Director, OERR
Director, Office of Solid Waste (OSW)
Deputy Director, OSW
Director, Technology Innovation office (TIO)
EPA Headquarters Library
EPA Regional Libraries
EPA Laboratory Libraries
------- |