[Federal Register Volume 70, Number 36 (Thursday, February 24, 2005)]
[Notices]
[Pages 9071-9077]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-3527]
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ENVIRONMENTAL PROTECTION AGENCY
[OW-2003-0028; FRL-7876-9]
RIN 2060-AD86
Drinking Water Contaminant Candidate List 2; Final Notice
AGENCY: Environmental Protection Agency.
ACTION: Notice.
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SUMMARY: The Safe Drinking Water Act (SDWA), as amended in 1996,
requires the Environmental Protection Agency (EPA) to publish a list of
contaminants that, at the time of publication, are not subject to any
proposed or promulgated national primary drinking water regulations,
that are known or anticipated to occur in public water systems, and
that may require regulations under SDWA (section 1412 (b)(1)). SDWA, as
amended, specifies that EPA must publish the first list of drinking
water contaminants no later than 18 months after the date of enactment,
i.e., by February 1998, and every five years thereafter.
The EPA published the first Candidate Contaminant List (CCL) in
March of 1998 (63 FR 10273). The second draft CCL (CCL 2) was published
on April 2, 2004 (69 FR 17406) and announced EPA's preliminary decision
to carry forward the remaining 51 contaminants on the 1998 CCL as the
draft CCL 2, provided information on EPA's efforts to expand and
strengthen the underlying CCL listing process to be used for future CCL
listings, and sought comment on the draft list as well as EPA's efforts
to improve the contaminant selection process for future CCLs. Today's
final CCL 2 carries forward the remaining 51 contaminants proposed on
April 2, 2004.
ADDRESSES: EPA has established a docket for this action under Docket ID
No. OW-2003-0028. All documents in the docket are listed in the EDOCKET
index at http://www.epa.gov/edocket. Although listed in the index, some
information is not publically available, i.e., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, is not placed on the Internet and will be
publically available only in hard copy form. Publically available
docket materials are
[[Page 9072]]
available either electronically in EDOCKET or in hard copy at the Water
Docket, EPA/DC, EPA West, Room B102, 1301 Constitution Avenue, NW.,
Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30
p.m., Monday through Friday, excluding legal holidays. The telephone
number for the Public Reading Room is (202) 566-1744, and the telephone
number for the Water Docket is (202) 566-2426. For access to docket
material, please call (202) 566-2426 to schedule an appointment.
FOR FURTHER INFORMATION CONTACT: For questions about this notice
contact Dan Olson, Standards and Risk Management Division, Office of
Ground Water and Drinking Water (MC-4607M), Environmental Protection
Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460; telephone
number: 202-564-5239; fax number: 202-564-3752; e-mail address:
[email protected]. For general information contact the EPA Safe
Drinking Water Hotline at (800) 426-4791 or e-mail: [email protected]. The Safe Drinking Water Hotline is open Monday through
Friday, excluding legal holidays, from 9 a.m. to 5 p.m.
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does This Action Impose Any Requirements on My Public Water System?
Today's action does not impose any requirements on anyone. Instead,
it notifies interested parties of EPA's final CCL 2 as well as EPA's
efforts to improve the contaminant selection process for future CCLs.
Contaminants on the list will be considered under the regulatory
determination provision of SDWA (see section 1412(b)(1)(B)(ii)), which
directs EPA to select at least five contaminants from the CCL every
five years to determine if regulating the contaminants through National
Primary Drinking Water Regulations would present a meaningful
opportunity to reduce health risk.
II. Background and Summary of Today's Action
A. What Is the Purpose of Today's Action?
The CCL is the primary source of priority contaminants for
evaluation by EPA's drinking water program. Contaminants on the CCL are
currently not subject to any proposed or promulgated national primary
drinking water regulation, but are known or anticipated to occur in
public water systems, and may require regulation under SDWA. The EPA
conducts research on health effects, analytical methods, contaminant
occurrence, treatment technologies, and treatment effectiveness for
priority drinking water contaminants on the CCL. The Agency also
develops drinking water guidance and health advisories, and makes
regulatory determinations for priority contaminants on the CCL.
Today's action informs interested parties of EPA's final CCL 2 as
well as EPA's efforts to improve the contaminant selection process for
future CCLs.
B. The Background of the CCL
The SDWA is the core statute protecting drinking water at the
Federal level. Under SDWA, EPA sets public health goals and enforceable
standards for drinking water quality. In 1996, Congress amended SDWA to
emphasize sound science and risk-based priority-setting. Congress also
changed the way drinking water regulatory priorities are set by
establishing the CCL requirements. The 1996 SDWA amendments require EPA
to (1) publish every five years a list of currently unregulated
contaminants in drinking water that may pose risks (the CCL), and (2)
make determinations on whether or not to regulate at least five of
these contaminants on a five year cycle, or three and a half years
after each CCL is published (SDWA section (b)(1)).
Today's action is being published pursuant to the requirements in
section 1412(b)(1). The contaminants included are not subject to any
proposed or promulgated national primary drinking water regulation, are
known or anticipated to occur in public water systems, and may require
regulation under the SDWA. A draft CCL 2 was published in the April 2,
2004 edition of the Federal Register (69 FR 17406) to announce EPA's
preliminary decision to carry forward the remaining 51 contaminants on
the 1998 CCL as the CCL 2, to provide information on EPA's efforts to
expand and strengthen the underlying CCL listing process to be used for
future CCL listings, and to seek comment on the draft list as well as
EPA's efforts to improve the contaminant selection process for future
CCLs.
Today's action establishes the final CCL 2 which includes 42
chemicals or chemical groups and nine microbiological contaminants.
This list continues to be an important tool under the SDWA to help
prioritize research and serves as the central focus of the regulatory
determination process noted previously. It is important to note,
however, that under the SDWA, the EPA may also make regulatory
determinations for any unregulated contaminant not on today's CCL (see
SDWA section 1412(b)(1)(B)(ii)(III)). Thus, the Agency has the
authority to act as necessary to protect public health as new
information becomes available.
III. Drinking Water Contaminant Candidate List 2
Table III-1 lists the contaminants on the final CCL 2. These
contaminants are identified by name and, where available, the Chemical
Abstracts Service Registry Number (CASRN). The final CCL 2 consists of
nine microbiological contaminants and 42 chemical contaminants or
contaminant groups.
Table III-1.--Final Drinking Water Contaminant Candidate List 2
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Microbiological contaminant candidates
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Adenoviruses Aeromonas hydrophila
Caliciviruses
Coxsackieviruses
Cyanobacteria (blue-green algae), other freshwater algae, and their
toxins
Echoviruses
Helicobacter pylori
Microsporidia (Enterocytozoon and Septata)
Mycobacterium avium intracellulare (MAC)
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Chemical contaminant candidates
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CASRN
1,1,2,2-tetrachloroethane................. 79-34-5
1,2,4-trimethylbenzene.................... 95-63-6
1,1-dichloroethane........................ 75-34-3
1,1-dichloropropene....................... 563-58-6
1,2-diphenylhydrazine..................... 122-66-7
1,3-dichloropropane....................... 142-28-9
1,3-dichloropropene....................... 542-75-6
2,4,6-trichlorophenol..................... 88-06-2
2,2-dichloropropane....................... 594-20-7
2,4-dichlorophenol........................ 120-83-2
2,4-dinitrophenol......................... 51-28-5
2,4-dinitrotoluene........................ 121-14-2
2,6-dinitrotoluene........................ 606-20-2
2-methyl-Phenol (o-cresol)................ 95-48-7
Acetochlor................................ 34256-82-1
Alachlor ESA & other acetanilide pesticide N/A
degradation products.
Aluminum.................................. 7429-90-5
Boron..................................... 7440-42-8
Bromobenzene.............................. 108-86-1
DCPA mono-acid degradate.................. 887-54-7
DCPA di-acid degradate.................... 2136-79-0
DDE....................................... 72-55-9
Diazinon.................................. 333-41-5
Disulfoton................................ 298-04-4
Diuron.................................... 330-54-1
EPTC (s-ethyl-dipropylthiocarbamate)...... 759-94-4
[[Page 9073]]
Fonofos................................... 944-22-9
p-Isopropyltoluene (p-cymene)............. 99-87-6
Linuron................................... 330-55-2
Methyl bromide............................ 74-83-9
Methyl-t-butyl ether (MTBE)............... 1634-04-4
Metolachlor............................... 51218-45-2
Molinate.................................. 2212-67-1
Nitrobenzene.............................. 98-95-3
Organotins................................ N/A
Perchlorate............................... 14797-73-0
Prometon.................................. 1610-18-0
RDX....................................... 121-82-4
Terbacil.................................. 5902-51-2
Terbufos.................................. 13071-79-9
Triazines and degradation products of including, but not limited
triazines. to Cyanazine 21725-46-2 and
atrazine-desethyl 6190-65-4
Vanadium.................................. 7440-62-2
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IV. Summary of Comments
The comment period on the April 2, 2004, Federal Register notice,
``Drinking Water Contaminant Candidate List 2; Notice'' (69 FR 17406)
ended on June 1, 2004. EPA received a total of seven comments that
focused on EPA's draft CCL 2 and EPA's efforts to improve the
contaminant selection process for future CCLs. EPA received two
comments from associations representing water utilities, one comment
from a State-related association, one comment from a water utility, one
comment from a State agency, one comment from an individual, and one
anonymous comment. A summary of these comments and EPA's response to
these comments follow. A complete copy of the public comments and the
Agency's responses are included in the Docket for today's action and
can be obtained at http://www.epa.gov/edocket/.
The majority of comments were supportive of the CCL process. The
comments on development of the draft CCL 2 focused on two key topic
areas: (1) Reassembling the CCL taking new available information into
account; suggestions on information that should be considered, and
contaminants that should be included or deleted from the CCL; and (2)
requests for information on the status of CCL-related research.
Comments on the development of future CCLs focused on four key topic
areas: (1) Expert judgement and transparency, (2) the role of data
quality, (3) a simplified approach with adaptive management for future
CCLs, and (4) the role of virulence factor activity relationships
(VFARs). The remainder of this section discusses these key areas in
turn.
A. Developing the draft CCL 2
1. Suggestions on new information and contaminants that should be
included or deleted from the CCL.
Comment Summary: Two commenters believe that EPA should create a
new CCL taking new available information into account. One commenter
recommended that EPA not carry forward five chemicals (1,1,2,2-
tetrachloroethane, 1,1-dichloropropene, 1,3-dichloropropane, 1,3-
dichloropropene, and 2,2, dichloropropane) currently on CCL 1 to CCL 2,
two commenters recommended that N-nitrosodimethylamine (NDMA) should be
added to the CCL, and one commenter recommended that enterotoxigenic
Escherichia coli (E. coli) be included on the final CCL 2.
Agency Response: In response to commenters who recommended that EPA
create a new CCL to take new available information into account, and
the suggestion that EPA remove five chemicals (1,1,2,2-
tetrachloroethane, 1,1-dichloropropene, 1,3-dichloropropane, 1,3-
dichloropropene, and 2,2, dichloropropane) from the CCL, EPA does not
believe that it is appropriate to create a new CCL, or remove any
contaminants from the CCL, at this time. Where there is adequate
information about a particular contaminant, EPA plans to make a
regulatory determination which will either remove that contaminant from
the CCL or start a national rule making process to set a national
primary drinking water regulation. With regard to future CCLs, EPA is
developing an expanded comprehensive system for evaluating a wider
range of existing information, identifying new data, and applying
revised screening criteria to generate the CCL 3 in response to
extensive recommendations from the National Academy of Sciences
National Research Council (NRC) and National Drinking Water Advisory
Council (NDWAC).
With specific regard to NDMA, there is already a substantive body
of health effects research that the Agency has relied upon to classify
it as a ``probable human carcinogen'' (USEPA, 1993). The key
information gap for this contaminant relates to occurrence in public
water system distribution systems. Some initial research has been
conducted in this area and the Agency plans to collect more
comprehensive occurrence information as part of the upcoming national
survey of key unregulated contaminants under section 1445(a)(2).
Regarding enterotoxigenic E. coli, EPA will be considering this
microbe as part of the revised and expanded CCL 3 review process. The
Agency believes that this will be a more appropriate and effective
approach for evaluating this bacteria in comparison to a wide range of
other microbes that will be considered under the broader analytical
approach recommended by the NRC and NDWAC.
2. Provide the status of CCL-related research, data collection, and
pending initiatives that have been undertaken since CCL 1.
Comment Summary: Commenters identified several CCL-related research
activities that have been undertaken since CCL 1 and requested that EPA
provide the status of CCL-related research, data collection, and
pending initiatives that have been undertaken since CCL 1.
Two commenters also requested information about the Agency's
progress to date and the intended future path for integrating the 35
deferred pesticides and 21 contaminants (suspected of having adverse
effects on endocrine function) into the CCL process.
Agency Response: EPA agrees that the status of CCL-related research
should be publically available. The Agency has taken a number of steps
to provide this information through its Web sites and in documents it
has published.
EPA Web sites addressing CCL-related research information include
the following:
EPA's Office of Ground Water and Drinking Water Drinking
Water Research Information Network (DRINK), found at http://www.epa.gov/safewater/drink/intro.html, is a publicly accessible, Web
based system that tracks over 1,000 ongoing research projects conducted
by EPA and other research partners from national, regional, and
international research agencies and organizations. The DRINK system
stores, manages, and delivers descriptive summary data on drinking
water-related projects, including abstracts, status of projects,
uniform resource locators to datasets and reports, and contact
information on projects.
EPA's Office of Ground Water and Drinking Water Web site
at http://www.epa.gov/safewater/ccl/cclfs.html has information on the
NDWAC (e.g., reports, meeting announcements, and meeting summaries
which includes meetings of the NDWAC CCL Work Group), monitoring of
unregulated contaminants from public water systems, the National
Contaminant Occurrence Database, analytical methods for compliance
monitoring, and treatment technologies.
EPA's Office of Research and Development (ORD)
environmental
[[Page 9074]]
information management system Web site at http://www.epa.gov/eims/
maintains information on EPA research projects, including project
title, abstract, start and end dates, principal investigator, funding,
results and publications, and related technical documents.
EPA's Office of Science and Technology Web site at http://www.epa.gov/waterscience/humanhealth/ has information on EPA's drinking
water standards, health and consumer advisories, criteria documents,
and related technical documents.
A key document addressing CCL-related research and information is
EPA's Draft Multi-Year Plan (MYP) for the drinking water research
program. The Draft MYP describes the Agency's drinking water research
program activities and plans for fiscal years 2003--2010 (see http://www.epa.gov/osp/myp/dw.pdf). As a tool for planning and communication,
the MYP provides: (1) A context for annual planning decisions and a
basis for describing the impacts of these decisions; (2) a framework
for integrating research on common issues across the EPA's ORD
laboratories and centers, as well as across the various Agency Goals
established under the Government Performance and Results Act; and (3) a
resource for communicating research plans and products within ORD and
with EPA programs, the regions and interested parties outside of EPA.
MYPs are updated on a biennial basis to provide opportunities for
making the necessary adjustments to the research program.
As discussed in the draft CCL 2 notice (69 FR 17406), EPA plans to
consider the deferred pesticides in the context of an improved approach
for selecting contaminants for future CCLs (CCL 3). This will enable
the Agency to consider these contaminants in a consistent, reproducible
manner with a wide range of other contaminants. In this regard, it is
important to note that EPA may conduct research, and make regulatory
determinations for any unregulated contaminant not on today's CCL (see
SDWA section 1412(b)(1)(B)(ii)(III)). Thus, the Agency has the
authority to act as necessary to protect public health as new
information becomes available.
As with pesticides, EPA believes that suspected endocrine
disruptors should be considered when the next CCL is developed. This
enables the Agency to use a more refined and improved approach in
evaluating these contaminants. As previously stated, EPA is not
restricted to the contaminants on this CCL for making regulatory
determinations.
B. Developing a Process for Future CCLs
There were four key issues identified by commenters on developing a
process for future CCLs. They are:
1. Expert judgement and transparency
2. The Role of Data Quality.
3. Simplified approach with adaptive management applied for future
CCLs.
4. The role of virulence factor activity relationships.
Each of these issues is discussed in turn below.
1. Expert Judgement and Transparency
Comment Summary: Two commenters stated that there is a need for the
CCL process to be a transparent process. The commenters stated that
they view the transparency of the CCL process as being critical to its
success so that both the regulated community and the public can
understand it. One commenter also recommended that the Agency combine
expert judgement and classification algorithms (a formula or set of
steps for solving a particular problem) in developing the CCL.
Classification algorithms or automated processes should serve as
mechanisms for screening down the number of contaminants that the
experts must then evaluate in greater depth.
Both commenters believe that the use of expert judgement can be
transparent and is an essential component to any future CCL process.
They urged EPA to clearly define the role of expert judgement including
the specific parts of the listing process where it would be used.
One commenter also suggested that the CCL process should be an
ongoing process within the Office of Water and that the Agency should
actively monitor appropriate peer-reviewed literature for new
contaminants, new methods, and new health effects data. In addition,
the Agency should also increase its involvement in ongoing symposia,
professional meetings, and workshops on topics relevant to the CCL.
Agency's Response: The Agency agrees with the commenters that
transparency and use of expert judgement should be important components
of the CCL process. These recommendations were included in both the NRC
report (NRC, 2001) and in the NDWAC Report on the CCL Classification
Process to the U.S. Environmental Protection Agency (NDWAC, 2004). The
Agency received the NDWAC report in May of 2004 and is currently
evaluating the recommendations.
The NRC and NDWAC reports recommend that the EPA conduct the CCL
process so that interested stakeholders have an opportunity to
participate at key steps in developing the CCL. Additionally the
reports recommend greater use of expert judgment and critical review of
the CCL classification process. While the reports did not provide
specific advice on how to accomplish these recommendations they did
identify key milestones, such as selecting sources of data and
developing criteria to select contaminants. Structuring the process
around such milestones should enhance transparency and facilitate
expert review.
The Agency continues to evaluate the NDWAC recommendation on how to
include expert judgment and conduct the CCL process in a transparent
manner and will consider these comments as future CCLs are developed.
2. The Role of Data Quality
Comment Summary: Two commenters stressed the importance of data
quality in the CCL process. Both commenters support the use of high
quality data and sound science in the CCL process.
The commenters expressed some concern about the current quality of
data used for the CCL process. The commenters suggested that EPA should
focus on using high quality data that are appropriate to support valid
characterization of a contaminant and that EPA maintains a focus on
data quality at each stage of the CCL process.
One commenter expressed an interest in participating in the ongoing
development and application of a viable data quality assurance system
that would support the data objectives for each step in the CCL
process.
Agency's Response: The NDWAC recommendations also discussed the
nature and type of data and information used in the CCL process. In
discussing information quality considerations, the Council noted that
data and information on contaminants considered in the CCL process will
consist of different types of data and that some contaminants will not
be robustly characterized. The report also recommends that while the
Agency should be explicit about how it selects data for the CCL
process, the process must have some flexibility to adequately consider
emerging contaminants. As the Agency develops the CCL process and
evaluates the NDWAC recommendations, it will consider the commenters'
recommendations as well as the SDWA data quality requirements.
[[Page 9075]]
3. Simplified Approach
Comment Summary: One commenter expressed concern over the NAS and
NDWAC recommendations, characterizing them as ``a theoretical and
esoteric process and not a pragmatic process.'' The commenter believes
that there is a need for the Agency to develop a simpler, more
streamlined approach that uses only the attributes of occurrence and
health effects and that potentially eliminates some of the major
complications associated with the NRC three-step, five-attribute CCL
process, thereby making the process more effective in the near term.
The NRC approach can serve as a useful guide for the Agency's long-term
CCL development effort; however, the details and logistics of the
approach require additional work.
One commenter was concerned about the resources and time needed to
develop the CCL using a new approach. The commenter suggested that
convening a series of workshops with external experts would be an
efficient way of addressing issues related to data quality, contaminant
attributes, training sets, process performance, and protocols for
classification algorithms.
Agency's Response: The NDWAC report provides a series of
recommendations for the Agency to consider as it develops the CCL
process. The NDWAC report also noted that the NRC three-step approach
using five attributes has merit, but identified practical limitations
or difficulties the Agency would need to address. For example, the
NDWAC report recommends that the Agency should consider classification
approaches but ``should use another approach for selecting contaminants
for the near term (i.e., for CCL 3) if there are difficulties that
cannot be overcome.'' The NDWAC report also identifies issues that the
Agency should consider in the NRC's recommendation on classification
approaches and emphasizes that the Agency should consider practical
constraints. The NDWAC report specifically recommended that the
screening step be as simple as possible, which would require fewer
resources and less time while adequately identifying those contaminants
of greatest significance. The report further encouraged the Agency to
consider whether fewer than the five attributes used in the NRC example
of a classification approach are adequate for a new CCL process. The
NDWAC report recognizes that the Agency will learn more about the CCL
process in each iterative step and recommended an adaptive management
approach to develop the CCL process. As the Agency evaluates the NDWAC
recommendations, it will consider the need for a pragmatic approach
using available resources for development of the next CCL and the most
efficient ways to incorporate expert involvement in the CCL process.
4. The Role of Virulence Factor Activity Relationship.
Comment Summary: A variety of comments were received on the
proposed role of genomic data and the VFAR concept for the CCL process.
Most of the commenters acknowledged that VFAR appears to be a powerful
and useful tool that shows great promise for future CCL development,
but felt that the Agency had not made clear how it proposes to use VFAR
technology.
The commenters suggested that the Agency is placing too much
emphasis on VFAR. One commenter stated that the Agency appears to be
relying too heavily on an advanced genomic technology. The commenter
expressed concerns that the technology's applications to environmental
samples are unproven and recommended that it not be used in the next
CCL process.
One commenter suggested that there are many unknown variables
associated with the VFAR concept and it should therefore be treated
with extreme caution. Two commenters are concerned that VFAR may not
offer practical solutions to immediate concerns regarding waterborne
disease and would require a multi-year commitment and collaboration by
EPA and other participating organizations before it would be useful.
Agency Response: The NRC (NRC, 2001) recommendations provided a
detailed discussion of the potential and proposed role of VFARs in the
CCL process. The VFAR principle can be described as comparing the gene
structure of newly identified waterborne pathogens to pathogens with
known genetic structures that have been associated with human disease.
Virulence factors are defined broadly by the NRC as the ability of
a pathogen to persist in the environment, gain entry into a host (e.g.,
humans), reproduce, and cause disease or other health problems either
because of its architecture or because of its biochemical compounds. A
number of virulence factors are known, including the ability of a
microbe to move within a host under its own power, the ability of
mechanisms to protect the microbe against the body's defenses (e.g.,
anti-phagocytosis mechanisms), the ability of a microbe to adhere or
attach to the surface of a host cell, and the ability of microbes to
produce toxins that injure host cells. The NDWAC was specifically
charged to provide an evaluation of the VFAR approach and to identify
studies that explore the feasibility of the approach. While the Agency
recognizes VFAR as a potential tool for future CCLs, EPA is not
planning to solely rely on the approach in the near term for CCLs. In
its deliberation, the NDWAC conducted several explorations and
literature reviews on the nature and type of genomic data available to
characterize genes that may be associated with virulence factors and an
organism's potential to cause harm. The reviews and analyses showed
that the technology, although powerful, still has serious limitations
for near term CCLs. The NDWAC provided a series of pragmatic
recommendations for considering pathogens for near term CCLs and
several recommendations for improving this process as genomic
technology and reporting improve. As the Agency develops the CCL
process for microbes it will take these comments under consideration.
V. Developing Future CCLs--NDWAC Recommendations and Next Steps
A. NDWAC Recommendations
In the Federal Register notice of April 2, 2004 (69 FR 17406), EPA
discussed the activities of the NRC and the NDWAC related to the CCL.
The EPA sought the advice of the NRC in response to comments received
during the development of the 1998 CCL, which advocated a broader, more
comprehensive approach for selecting contaminants.
The Agency asked the NRC to address three key topics related to
drinking water contaminant selection and prioritization:
1. What approach should be used to develop future CCLs?
2. How best should EPA assess emerging drinking water contaminants
and related databases to support future CCL efforts?
3. What approach should EPA use to set priorities for contaminants
on the CCL?
The NRC's findings and recommendations on these topics were
published in three reports: Setting Priorities for Drinking Water
Contaminants (NRC, 1999a), Identifying Future Drinking Water
Contaminants (NRC, 1999b), and Classifying Drinking Water Contaminants
for Regulatory Consideration (NRC, 2001).
The NRC recommendations provided a framework for evaluating a
larger number of contaminants and making decisions about contaminants
for which
[[Page 9076]]
data are limited through the use of innovative technologies and expert
advice. The EPA requested the assistance of NDWAC to evaluate and
provide advice on implementing the NRC's recommended classification
process.
The NDWAC formed the CCL Classification Process Work Group (the
Work Group) and charged it with reviewing the NRC 2001 report. The Work
Group was asked to advise the NDWAC on development and application of
the classification approach suggested by the NRC, including evaluating
proposed and alternative methodologies. The Work Group met 10 times
from September of 2002 to March of 2004. All Work Group meetings were
open to the public and announced in the Federal Register. In conducting
its review, the Work Group considered the large and growing number of
agents that might become candidates for scrutiny in the CCL process,
and the rapid expansion of information on these agents. Based on this
review, the Work Group provided the following recommendations:
1. There is merit in the three-step selection process proposed by
NRC for classifying chemical and microbial contaminants. The NDWAC
believes the three-step process should involve identification of the
CCL universe, screening the universe to a preliminary CCL, and
selecting the CCL from the Preliminary CCL.
2. The NDWAC recommends that the Agency should move forward with
the NRC recommendation to develop and evaluate some form of prototype
classification approach. (A prototype classification uses computer-
based computational tools to weigh selected contaminant characteristics
against the characteristics of various classes of drinking water
contaminants whose occurrence and health effects are relatively well
understood.)
3. The NDWAC believes that expert judgment plays an important role
throughout the three-step selection process, particularly in reviewing
the prototype model and the output of the new classification approach.
4. The NDWAC recommended enhancing the surveillance for emerging
chemical and microbial contaminants and also soliciting information
from the public via a nomination process to assure a full consideration
of potential contaminants.
The NDWAC also identified a number of practical limitations or
difficulties in developing and applying the recommended approach and
provided advice on how these might be addressed.
The NDWAC presented the final report to the Administrator on May
19, 2004. The report, entitled National Drinking Water Advisory Council
Report on the CCL Classification Process to the U.S. Environmental
Protection Agency provides a detailed summary of the questions
considered by the NDWAC, the analyses conducted to explore the
questions, key points discussed, and the NDWAC's recommendations and
rationale for the recommendations. The report is available at http://www.epa.gov/safewater/ndwac/council.html.
B. Next Steps
The Agency is working to evaluate the NDWAC recommendations and to
meet the statutory deadline to issue the next CCL. The NDWAC
recommendations encourage the Agency to consider the practical
limitations identified in their report and to use an adaptive
management approach to develop CCLs. This adaptive management approach
will enable the Agency to identify which recommendations can be
implemented for the next CCL while learning from and improving upon
each successive listing process and at the same time protecting public
health. In its development of a new CCL process, the Agency will focus
on several areas in the near future and continue to seek input and
advice from experts and interested stakeholders. Some of the key areas
to be explored in developing the new CCL process are discussed below.
The NDWAC recommended that microbial and chemical contaminants be
evaluated by parallel processes that meet in the formation of a single
CCL. The Agency is developing parallel processes for microbial and
chemical contaminants that take into account the systematic differences
in how these contaminants are characterized and take the best advantage
of the information available for microbial and chemical contaminants.
The Agency is also considering approaches and opportunities to seek
out and incorporate input from experts and interested stakeholders as
the CCL process is developed. EPA held a public meeting on September
15, 2004, to provide an update on its efforts to improve upon the CCL
process. The Agency is also consulting with interested stakeholders on
how to increase expert involvement in the process and on opportunities
to gather information on new and emerging contaminants through
professional conferences, focused workshops, and coordination with
other Federal and State agencies. The Agency will provide additional
opportunities for the exchange of information with the public before
the next CCL is proposed in the Federal Register.
The Agency is evaluating data sources that characterize a
contaminant's potential to occur in drinking water and produce adverse
health effect. The evaluation will consider the NRC and NDWAC
recommendations as well as SDWA requirements in selecting information
and data to consider for the next CCL. This evaluation will identify
the best available data that for use in the CCL process and result in a
process to compile information for a significantly larger group of
chemical and microbial contaminants than initially considered for CCL
1.
The Agency anticipates conducting analyses to identify specific
criteria related to occurrence and health effects associated with
contaminants that could be used to select contaminants for the CCL. The
Agency is evaluating the NDWAC recommendation to develop a series of
screening criteria that would identify contaminants for additional
scrutiny and prioritization. The NDWAC recommendations provide insight
on the occurrence and health effects data that the Agency could use to
identify a smaller set of contaminants for additional evaluation but
does not recommend specific levels or criteria to implement the
screening process.
The NDWAC also recommended that the Agency explore the use of
classification approaches to identify contaminants for consideration
for the CCL. The Agency is evaluating the requirements for a
classification approach for the next CCL and anticipates seeking
additional advice from experts and stakeholders. EPA will need to
evaluate various classification approaches, consider the range of
potential performance indicators, conduct calibration and validation
analyses, and engage experts in the evaluation of the selected
approach(es) and associated validation results.
As a new CCL process is developed and implemented for the next
list, the Agency will provide updates and information on the process.
The CCL process is a critical input to shaping the future direction of
the drinking water program. The Agency anticipates that improvements to
the process will result in a more comprehensive approach to developing
the CCL.
VI. References
Federal Register, Vol. 63, No. 40. Announcement of the Drinking
Water Contaminant Candidate List; Notice. March 2, 1998. 10273. (63
FR 10273).
Federal Register, Vol. 69, No. 64. Drinking Water Contaminant
Candidate List 2;
[[Page 9077]]
Notice. April 2, 2004. 17406. (69 FR 17406).
National Drinking Water Advisory Council (NDWAC). 2004. National
Drinking Water Advisory Council Report on the CCL Classification
Process to the U.S. Environmental Protection Agency. Available at
http://www.epa.gov/safewater/ndwac/council.html.
National Research Council (NRC). 1999a. Setting Priorities for
Drinking Water Contaminants. National Academy Press, Washington, DC
http://www.nap.edu/catalog/6294.html.
National Research Council (NRC). 1999b. Identifying Future Drinking
Water Contaminants. National Academy Press, Washington, DC http://www.nap.edu/catalog/9595.html.
NRC. 2001. Classifying Drinking Water Contaminants for Regulatory
Considerations. National Academy Press, Washington, DC http://books.nap.edu/books/0309074088/html/index.html.
USEPA. 1993. N-nitrosodimethylamine; CASRN 62-75-9, Integrated Risk
Information Service (IRIS). Carcinogenicity assessment last updated
July 1, 1993.
Dated: February 17, 2005.
Benjamin H. Grumbles,
Assistant Administrator, Office of Water.
[FR Doc. 05-3527 Filed 2-23-05; 8:45 am]
BILLING CODE 6560-50-P