The EPA announced on Thursday, Oct. 8, 2009, that the agency is publishing it third Contaminant Candidate List (CCL 3) since the Safe Drinking Water Act (SDWA) amendments of 1996.

The draft CCL 3 was published on Feb. 21, 2008 (73 FR 9628; USEPA 2008a), and included 93 chemicals or chemical groups and 11 microbiological contaminants, and asked for comments. While most comments stuck to praising the agency's efforts in this matter, the agency apparently received enough advice to bump the number of chemicals to a final 116 candidate chemicals that presented possible health risks.

The CCL 3 is a list of contaminants that are currently not subject to any proposed or promulgated national primary drinking water regulations, that are known or anticipated to occur in public water systems, and which may require regulation under SDWA. The final CCL 3 includes 104 chemicals or chemical groups and 12 microbiological contaminants.

The Safe Drinking Water Act provides the EPA with the authority to require all large and a subset of small systems to monitor for up to 30 unregulated contaminants every five years under the Unregulated Contaminant Monitoring Regulation (UCMR). The second unregulated contaminant monitoring rule (UCMR 2), which was promulgated on Jan. 4, 2007 (72 FR 367; USEPA, 2007a), requires monitoring for several pesticides and pesticide degradates, five polybrominated diphenyl ether (PBDE) flame retardants, a group of nitrosamines, and two munitions (TNT and RDX). All of the chemicals on UCMR 2 were included among the contaminants evaluated for CCL 3.

In developing the draft CCL 3, EPA implemented a new process from that used for CCL 1 and CCL 2. This new process built on evaluations from previous CCLs, and was based on substantial expert input and recommendations from various groups, including the National Academy of Science's National Research Council (NRC) and the National Drinking Water Advisory Council (NDWAC). This process is summarized in the draft CCL 3 notice in the Federal Register.

The Final Contaminant Candidate List 3 is as follows:  

Chemical Contaminants

 

CASRN	Common name
630206	1,1,1,2-Tetrachloroethane
75343	1,1-Dichloroethane
96184	1,2,3-Trichloropropane
106990	1,3-Butadiene
99650	1,3-Dinitrobenzene
123911	1,4-Dioxane
57910	17 alpha-Estradiol
71363	1-Butanol
109864	2-Methoxyethanol
107186	2-Propen-1-ol
16655826	3-Hydroxycarbofuran
101779	4,4'-Methylenedianiline
30560191	Acephate
75070	Acetaldehyde
60355	Acetamide
34256821	Acetochlor
187022113	Acetochlor ethanesulfonic acid (ESA)
184992444	Acetochlor oxanilic acid
630206	1,1,1,2-Tetrachloroethane
75343	1,1-Dichloroethane
96184	1,2,3-Trichloropropane
106990	1,3-Butadiene
99650	1,3-Dinitrobenzene
123911	1,4-Dioxane
57910	17 alpha-Estradiol
71363	1-Butanol
109864	2-Methoxyethanol
107186	2-Propen-1-ol
16655826	3-Hydroxycarbofuran
101779	4,4'-Methylenedianiline
30560191	Acephate
75070	Acetaldehyde
60355	Acetamide
34256821	Acetochlor
187022113	Acetochlor ethanesulfonic acid (ESA)
184992444	Acetochlor oxanilic acid (OA)
107028	Acrolein
142363539	Alachlor ethanesulfonic acid (ESA)
171262172	Alachlor oxanilic acid (OA)
319846	Alpha-Hexachlorocyclohexane
62533	Aniline
741582	Bensulide
100447	Benzyl chloride
25013165	Butylated hydroxyanisole
133062	Captan
14866683	Chlorate
74873	Chloromethane (Methyl chloride)
110429624	Clethodim
7440484	Cobalt
80159	Cumene hydroperoxide
NA	Cyanotoxins
141662	Dicrotophos
55290647	Dimethipin
60515	Dimethoate
298044	Disulfoton
330541	Diuron
517099	Equilenin
474862	Equilin
114078	Erythromycin
50282	Estradiol (17-beta estradiol)
50271	Estriol
53167	Estrone
57636	Ethinyl Estradiol (17-alpha Ethynyl Estradiol)
13194484	Ethoprop
107211	Ethylene glycol
75218	Ethylene oxide
96457	Ethylene thiourea
22224926	Fenamiphos
50000	Formaldehyde
7440564	Germanium
74975	Halon 1011 (bromochloromethane)
75456	HCFC-22
110543	Hexane
302012	Hydrazine
72333	Mestranol
10265926	Methamidophos
67561	Methanol
74839	Methyl bromide (Bromomethane)
1634044	Methyl tert-butyl ether
51218452	Metolachlor
171118095	Metolachlor ethanesulfonic acid (ESA)
152019733	Metolachlor oxanilic acid (OA)
2212671	Molinate
7439987	Molybdenum
98953	Nitrobenzene
55630	Nitroglycerin
872504	N-Methyl-2-pyrrolidone
55185	N-Nitrosodiethylamine (NDEA)
62759	N-nitrosodimethylamine (NDMA)
621647	N-Nitroso-di-n-propylamine (NDPA)
86306	N-Nitrosodiphenylamine
930552	N-nitrosopyrrolidine (NPYR)
68224	Norethindrone (19-Norethisterone)
103651	N-Propylbenzene
95534	O-Toluidine
75569	Oxirane, methyl
301122	Oxydemeton-methyl
42874033	Oxyfluorfen
14797730	Perchlorate
1763231	Perfluorooctane sulfonic acid (PFOS)
335671	Perfluorooctanoic acid (PFOA)
52645531	Permethrin
41198087	Profenofos
91225	Quinoline
121824	RDX
135988	Sec-Butylbenzene
7440246	Strontium
107534963	Tebuconazole
112410238	Tebufenozide
13494809	Tellurium
13071799	Terbufos
56070167	Terbufos sulfone
59669260	Thiodicarb
23564058	Thiophanate-methyl
26471625	Toluene diisocyanate
78488	Tribufos
121448	Triethylamine
76879	Triphenyltin hydroxide (TPTH)
51796	Urethane
7440622	Vanadium
50471448	Vinclozolin
137304	Ziram

 

Microbial Contaminants

   

Name
Adenovirus
Caliciviruses
Campylobacter jejuni
Enterovirus
Escherichia coli (0157)
Helicobacter pylori
Hepatitis A virus
Legionella pneumophila
Mycobacterium avium
Naegleria fowleri
Salmonella enterica
Shigella sonnei