United States Environmental Protection Office of Water EPA 815-F-97-001 Agency 4607 October 1997 £EPA DRINKING WATER CONTAMINANT CANDIDATE LIST- OPEN FOR COMMENT The Safe Drinking Water Act (SDWA), as amended in 1996, requires that, when selecting drinking water contaminants for regulation, the Environmental Protection Agency gives priority to those that present the greatest public health concern, especially to vulnerable populations such as infants, the elderly and those with serious illness. To achieve this, we are developing a Drinking Water Contaminant Candidate List (CLL). We have published a draft list in the October 6,1997 Federal Register (62 FR 52193) and seek input from the public before finalizing it by February 1998. What is the Drinking Water Contaminant Candidate List? The CCL is a list of contaminants known or anticipated to occur in public water systems. Contaminants listed on the CCL will undergo a selection process which will determine our priorities for research, guidance and possible regulation. At the time of publication, these contaminants are not subject to any proposed or promulgated national primary drinking water regulation (NPDWR), but they may require regulation under the SDWA. The draft CCL was developed with considerable input from the scientific community and other interested parties. It is currently open for comment and will be finalized no later than February 1998. A new CCL will be published every five years. If a candidate is on the list, will it be regulated? Not necessarily. If a contaminant is listed on the CCL, a team of scientists and other experts will use the list to • select contaminants for possible regulation, guidance development and health advisories, • monitor when and where these contaminants occur and where more data is needed, • determine our research priorities. By 2001, EPA must select five or more candidates from the CCL and determine whether or not to regulate them. This determination is based on whether regulating the contaminant would present a meaningful opportunity for health risk reduction. In addition to selecting candidates for possible regulation, we will identify a maximum of 30 contaminants from the list for unregulated monitoring. This data will be used hi our drinking water research. How were the contaminants identified for the draft Contaminant List, and who was involved in the process? In December 1996, the EPA called a meeting of the new National Drinking Water Advisory Committee (NDWAC) Working Group on Occurrence and Contaminant Selection. The working group includes representatives of public water utilities, environmental and public interest groups, state regulatory agencies, public health offices, and other interested parties. At the December stakeholders meeting, the group suggested using the following criteria identify candidates: ------- • Does the contaminant adversely affect public health? • Is the contaminant known or substantially likely to occur in public water systems with a frequency and at levels posing a threat to public health? When will the CCL be finalized, and what happens next? The CCL will be published no later than February 1998, after the public has the opportunity to comment. Once the CCL is finalized, the next step will be to select five or more contaminants and determine whether or not a regulation is needed. This step will be followed by proposal and ultimate promulgation of regulations for those contaminants where a determination has been made to regulate. The CCL will be revised every five years, with considerable input from the public, and the regulatory selection process will repeat. What other tools will EPA use in its contaminant selection process? In developing future CCLs, the EPA will use the National Contaminant Occurrence Database (NCOD) and a new regulation for Unregulated Contaminant Monitoring (UCM). EPA is working to establish both the NCOD and the UCM regulation by August 1999, as required by SDWA. The database will include the occurrence of both regulated and unregulated contaminants. It will provide the basis for identifying contaminants that may be placed on future CCLs and support the EPA Administrator's decisions to regulate contaminants in the future. The database is also expected to support the review of existing regulations and monitoring requirements every six years. EPA is required by the SDWA, as amended in 1996, to list and develop regulations for monitoring of certain unregulated contaminants by August 1999, and every 5 years thereafter [Section 1445(a)(2)]. The list must not exceed 30. Contaminants on the CCL that need additional occurrence data will be used as the source of contaminants for the list of unregulated contaminants. Data will be collected and maintained in the National Drinking Water Contaminant Occurrence Database. Criteria for determining which contaminants on the CCL will be chosen for the unregulated contaminant monitoring list will be developed as part of this regulation. How can I get involved? Send us your comments — we need your input! We are specifically looking for comments on (1) the approach we used to create this list and suggestions on our process for future lists; (2) contaminants on the list; (3) data needs categories (refer to the Federal Register notice); and (4) whether to include perchlorate on the CCL. Comments must be received or postmarked by midnight December 5, 1997. To submit comments by mail, send an original and three copies of your comments and enclosures (including references), in hard copy or on a disc in WordPerfect 5.1 or ASCII file format, to Comment Clerk To submit comments electronically (you can Docket Number W-97-11 do this at Federal Depository Libraries): Water Docket (MC4101) • Use ASCII format, USEPA, 401 M. St., SW • Avoid using special characters and any Washington, DC, 20460 form of encryption, • Specify the docket number W-97-11, • Send to: ow-docket@epamail.epa.gov. ------- Draft Drinking Water Contaminant Candidate List Inorganic Contaminants (8) Aluminum 7429-90-5 Boron 7440-42-8 Manganese 7439-96-5 Nickel Zinc 7440-66-6 Sodium 7440-23-5 Vanadium 7440-62-2 Sulfate Synthetic Organic Contaminants (26) 1,1,2,2-tetra-chloroethane 79-34-5 1,2,4-trimethylbenzene 95-63-6 1,1-dichloro-ethane 75-34-3 1,1-dichloro-propene 563-58-6 1,2-diphenylhydrazine 122-66-7 1,3-dichloropropane 142-28-9 2,4,6-trichlorophenol 88-06-2 2,2-dichloro-propane 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 2,6-di-tert-butyl -p-benzoquinone 719-22-2 2-methyl-Phenol (o-cresol) 95-48-7 Acetone 67-64-1 Bromobenzene 108-86-1 Cumene (isopropylbenzene) 98-82-8 p-Cymene (p-isopropyltoluene) 99-87-6 HexachJoro-butadiene 87-68-3 Methyl bromide 74-83-9 Methyl-t-butyl ether (MTBE) 1634-04-4 Naphthalene 91-20-3 Nitrobenzene 98-95-3 Organo tins RDX 121-82-4 Rhodamine WT Pesticides (24) 1,3-Dichloropropene (telone or 1,3-D) 542-75-6 Acetochlor 34256-82-1 Alachlor ES A (a degradation product of the pesticide alachlor) Pesticides, continued... Alidcarb, Aldicarb sulfoxide, Aldicarb sulfone) Aldrin 309-00-2 Atrazine-desethyl (a triazine dedgradation product) 6190-65-4 Cyanazine 21725-46-2 DCPA mono-acid degradate 887-54-7 DCPA di-acid degradate 2136-79-0 DDE 72-55-9 Diazinon 333-41-5 Dieldrin 60-57-1 Dimethoate 60-51-5 Disulfoton 298-04-4 Diuron 330-54-1 EPIC 759-94-5 Fonofos 944-22-9 Linuron 330-55-2 Metolachlor 51218-45-2 Metribuzin 21087-64-9 Molinate 2212-67-1 *Perchlorate Prometon 1610-18-0 Terbacil 5902-51-2 Terbufos 13071-79-9 Microbiological Contaminants (13) Acanthamoeba (guidance expected for contact lens wearers) adenoviruses Aeromonas hydrophila caliciviruses coxsackieviruses Cyclospora cayetanensis echoviruses Helicobacter pylori hepatitis A virus Legionella (in ground water) Microsporidia (Enferocytozoon & Septata) Mycobacterium avium intracellulare (MAC) Toxoplasma gondii * Under evaluation for addition to the CCL. See Federal Register notice for details. ------- Figure 1. Illustration of Decision Tool Used to Develop the Draft Contaminant Candidate List 391 drawn from: 1991 DWPL, health advisories, IRIS, CERCLA, TRI, OPP Ranking, PWS data, Stakeholders, SDWA Hotline, and literature 391 contaminants including 25 microorganisms 262 chemical contaminants Criteria focused on occurrence in water at levels of health concern, or indications of occurrence (production, release, coupled with properties). Health effects concentrations were used to determine significance of occurrence. additional contaminants sulfate, nickel, and aldicarbs 21 solely suspected of endocrine disrpution Deferred 83 6 SDWA Hotline 77 duplicates, or regulated Removed from consideration Data & information gathering & evaluation using Criteria Expert Panel microbial contaminants 29 chemical contaminants No data available EPA sought input from international panel of professional microbiologists. The input was presented to the Working Group for review & approval. 143 chemical contaminants Not Recommended for the List based on data evaluation 35 pesticides Deferred 71 contaminants 13 microbiological 58 chemical ------- |