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EWG Statement, 03/10/2008

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NATIONAL SUMMARY

Quality Varies Across the U.S.

CONTAMINANTS DATABASE

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Status: Regulated - EPA has established a maximum legal limit in tapwater for this contaminant.

Selenium (total) is a metal from mining or petrolum refining pollution; erosion of natural deposits. Potential health impacts associated with Selenium (total) include cardiovascular or blood toxicity, developmental toxicity, gastrointestinal or liver toxicity, kidney toxicity, neurotoxicity, reproductive toxicity, respiratory toxicity, and skin sensitivity. [read more]

Sources of Selenium (total):

	Industry
	Naturally Occurring (naturally present but increased for lands denuded by sprawl, agriculture, or industrial development)

An Environmental Working Group analysis of Selenium (total) tests reported by 29,002 public water suppliers in 41 states shows that between 1998 and 2003, 47.2 million people in 4,561 communities drank water contaminated with Selenium (total). In 39 of these communities, tap water was contaminated at levels above health-based thresholds.

Exposure Summary

47,190,086 People drinking water contaminated with Selenium (total) 4,561 Communities served water contaminated with Selenium (total) 2,184,722 People drinking water contaminated with Selenium (total) over health based limits 39 Communities served water with Selenium (total) above health based limits

Table. Selenium (total) Exposure by State

2.2 million Americans in 7 states were served tap water contaminated with Selenium (total) at levels above health-based limits between 1998 and 2003.

State	Water suppliers with Selenium (total) contamination		Water suppliers reporting Selenium (total) above health-based limits
	Systems	Population	Systems	Population
Florida	507	5,110,376	1	2,100,000
Idaho	32	129,502	24	74,450
California	274	13,224,958	3	7,375
Texas	1,114	10,659,438	6	1,257
Nebraska	153	424,439	2	910
Colorado	198	1,366,932	2	580
Arizona	153	1,722,778	1	150
Michigan	509	2,753,307	0	0
Nevada	119	2,082,484	0	0
Utah	252	1,846,134	0	0
Pennsylvania	131	1,290,727	0	0
Illinois	128	1,050,141	0	0
New Jersey	39	840,261	0	0
Tennessee	21	698,139	0	0
New Mexico	227	573,439	0	0
Kentucky	54	518,653	0	0
Ohio	19	506,535	0	0
Indiana	39	438,175	0	0
Washington	36	356,781	0	0
Wisconsin	141	346,748	0	0
North Dakota	135	256,783	0	0
Delaware	7	202,577	0	0
Missouri	59	201,998	0	0
Iowa	11	126,253	0	0
North Carolina	66	124,000	0	0
Virginia	8	102,601	0	0
Maine	34	67,727	0	0
New York	18	58,360	0	0
Wyoming	25	41,791	0	0
Oregon	9	33,992	0	0
Arkansas	3	8,902	0	0
South Carolina	15	8,098	0	0
Minnesota	2	7,980	0	0
Alaska	10	5,051	0	0
Montana	11	2,266	0	0
New Hampshire	2	1,760	0	0
Total	4,561	47,190,086	39	2,184,722

Table. The most polluted communities

2.2 million Americans in 39 communities were served tap water contaminated with Selenium (total) above health based limits between 1998 and 2003

Ranked by highest average Selenium (total) level

Rank	System	Population Served	Positive test results of total reported tests	Average Level (Range)
1	Rigby Country Living Center Rigby, ID	25	1 of 1	900 ppb (900 to 900 ppb)
2	Valleyview Estates Pocatello, ID	74	1 of 2	415 ppb (0 to 830 ppb)
3	Thatcher Water Company Thatcher, ID	25	1 of 1	400 ppb (400 to 400 ppb)
4	Resthaven Mobile Home Park Paso Robles, CA	75	3 of 3	393.33 ppb (240 to 490 ppb)
5	Banida Winder Water and Sewer District Preston, ID	195	2 of 3	300 ppb (0 to 600 ppb)
6	Wildhorse Ridge Subd Pocatello, ID	50	1 of 3	300 ppb (0 to 900 ppb)
7	Sunset Ranch Subd	31	1 of 2	300 ppb (0 to 600 ppb)
8	Star Sewer and Water District Water Syst Star, ID	1,344	1 of 2	300 ppb (0 to 600 ppb)
9	Sitgreaves Water Company Show Low, AZ	150	7 of 8	277.5 ppb (0 to 340 ppb)
10	Lewiston Orchards Irrigation Dist Lewiston, ID	18,000	1 of 3	266.67 ppb (0 to 800 ppb)

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Health based limits for Selenium (total)

Health Limit	Limit Value	Limit Description
Maximum Contaminant Limit (MCL)	50 ppb	The enforceable standard which defines the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to health-based limits (Maximum Contaminant Level Goals, or MCLGs) as feasible using the best available analytical and treatment technologies and taking cost into consideration. Source: U.S. Environmental Protection Agency.
Maximum Contaminant Limit Goal (MCLG)	50 ppb	A non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.
EPA Human Health Water Quality Criteria	170 ppb	Water quality criteria set by the US EPA provide guidance for states and tribes authorized to establish water quality standards under the Clean Water Act (CWA) to protect human health. These are non-enforceable standards based upon exposure by both drinking water and the contribution of water contamination to other consumed foods. Source: U.S. Environmental Protection Agency.
Lifetime health-based limit, non-cancer risk	50 ppb	Concentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic health effects for a lifetime of exposure. The Lifetime health-based limit (or Health Advisory, HA) is based on exposure for a a 70-kg adult consuming 2 liters of water per day. Source: U.S. Environmental Protection Agency.
Drinking Water Equivalent Level	200 ppb	A lifetime exposure concentration protective of adverse, noncarcinogenic health effects, that assumes all of the exposure to a contaminant is from drinking water. Source: U.S. Environmental Protection Agency.

Testing Summary for Selenium (total)

Water suppliers report an average of 0.4 Selenium (total) tests per year. 10,749 water suppliers failed to report any Selenium (total) tests at all.

Are tests routinely required for Selenium (total) by federal law? Yes Water suppliers reporting tests for Selenium (total) (1998-2003): 29,002 of 39,751 Average testing rate for water supplier reporting tests (1998-2003): 0.4 per year

Selenium (total) Violations

Table. 2.5 percent of all water suppliers violated safe drinking water standards for Selenium (total) between 1998 and 2003

Violation Type	Violations	Systems
Any Violation (1998-2003)	1,806	1,411
	(2.5% of all suppliers)
Testing violations (1998-2003)	1,735	1,394
	(2.4% of all suppliers)
Reporting violations (1998-2003)	5	2
	(< 0.1% of all suppliers)
Violations of tap water pollution standards (1998-2003)	66	19
	(< 0.1% of all suppliers)