[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