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EWG Statement, 03/10/2008

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NATIONAL SUMMARY

Quality Varies Across the U.S.

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Status: Unregulated - EPA has not established a maximum legal limit in tapwater for this contaminant.

Metribuzin is an herbicide used primarily on soybeans, potatoes, and alfalfa. Potential health impacts associated with Metribuzin include developmental toxicity, endocrine toxicity, gastrointestinal or liver toxicity, and kidney toxicity.

Sources of Metribuzin:

Agriculture (pesticides, fertilizer, factory farms)

An Environmental Working Group analysis of Metribuzin tests reported by 16,686 public water suppliers in 37 states shows that between 1998 and 2003, 1.9 million people in 22 communities drank water contaminated with Metribuzin. Metribuzin remains unregulated in tap water, without a maximum legal limit.

Exposure Summary

1,878,700 People drinking water contaminated with Metribuzin 22 Communities served water contaminated with Metribuzin

Table. Metribuzin Exposure by State

1.9 million Americans in 9 states were served tap water contaminated with Metribuzin between 1998 and 2003.

State	Water suppliers with Metribuzin contamination
	Systems	Population
Ohio	2	961,974
Arizona	4	859,316
Missouri	7	46,290
Nevada	1	8,100
Iowa	1	1,898
Illinois	1	392
California	1	350
Wisconsin	4	317
Maine	1	63
Total	22	1,878,700

Table. The most polluted communities

1.9 million Americans in 22 communities were served tap water contaminated with Metribuzin between 1998 and 2003

Ranked by highest average Metribuzin level

Rank	System	Population Served	Positive test results of total reported tests	Average Level (Range)
1	Snell Hill Village Mhp Lewiston, ME	63	1 of 1	5 ppb (5 to 5 ppb)
2	Rio Rico Utilities, Inc. Rio Rico, AZ	10,257	1 of 9	2.78 ppb (0 to 25 ppb)
3	City of Hillsboro Water Hillsboro, OH	6,368	1 of 1	2 ppb (2 to 2 ppb)
4	Tucson Municipal Water Deptartment Tucson, AZ	668,000	2 of 62	0.81 ppb (0 to 25 ppb)
5	Lisbon Water Supply Lisbon, IA	1,898	1 of 2	0.7 ppb (0 to 1.4 ppb)
6	Newell County Water District Tulelake, CA	350	1 of 1	0.25 ppb (0.25 to 0.25 ppb)
7	Oak Lane Mobile Home Park Stevens Point, Wi, WI	90	1 of 1	0.2 ppb (0.2 to 0.2 ppb)
8	Glen Flora Glen Flora, WI	150	1 of 1	0.1 ppb (0.1 to 0.1 ppb)
9	Riverside Apts Burlington, WI	37	1 of 1	0.1 ppb (0.1 to 0.1 ppb)
10	Jensens Mobile Home Village Waterford, WI	40	1 of 1	0.1 ppb (0.1 to 0.1 ppb)

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Health based limits for Metribuzin

Health Limit	Limit Value	Limit Description
Children's health-based limit for 1-day exposure	5000 ppb	Concentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic health effects for up to one day of exposure. The One-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.
Children's health-based limit for 10-day exposure	5000 ppb	Concentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic effects for up to ten days of exposure. The Ten-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.
Lifetime health-based limit, non-cancer risk	200 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	900 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 Metribuzin

Water suppliers report an average of 0.5 Metribuzin tests per year. 23,065 water suppliers failed to report any Metribuzin tests at all.

Are tests routinely required for Metribuzin by federal law? No Water suppliers reporting tests for Metribuzin (1998-2003): 16,686 of 39,751 Average testing rate for water supplier reporting tests (1998-2003): 0.5 per year

Metribuzin Violations

Because Metribuzin is unregulated in tap water, no violations are recorded in EPA's violations database, the Safe Drinking Water Information System. Under the federal tap water law, water suppliers are not required to routinely test for Metribuzin, and any level is legal in tap water.