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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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Tap Water Quality Report The State of Oklahoma 1,146 Water Systems Serving 3,441,376 People

An Environmental Working Group analysis of tap water tests from 1998 through 2003 for 1,146 communities across Oklahoma shows 56 pollutants were found in drinking water across the state.

Pollution Summary

56 25	7 2	14 6	40 13	18 12	10 7
Total pollutants	Agricultural pollutants	Sprawl and Urban pollutants	Industrial pollutants	Water Treatment and Distribution Byproducts	Naturally occurring pollutants
Number of pollutants detected (1998 - 2003)			Over health based limits

NOTE: Health based limits included in this analysis include enforceable drinking water limits (called Maximum Contaminant Limits, or MCLs) as well as governmental, non-enforceable health guidelines, such as Maximum Contaminant Limit Goals (MCLGs), lifetime health advisory levels, one-day and ten-day advisory levels to protect children from non-cancer health endpoints, and other government-established health guidelines for tap water contaminants.

Health Summary

The federal government has set standards for 80 chemical pollutants in tap water, balancing health concerns and treatment costs.

Contaminants found in state tap water (1998-2003): 56

Total population exposed above health-based limits: 2,126,548

Communities served water with contaminants above health-based limits: 316

Health effects or target organs of contaminants found: Cardiovascular or Blood Toxicity, Cancer, Developmental Toxicity, Endocrine Toxicity, Immunotoxicity, Kidney Toxicity, Gastrointestinal or Liver Toxicity, Neurotoxicity, Reproductive Toxicity, Respiratory Toxicity, and Skin Sensitivity.

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Contaminants found above health based limits: 25

Rank	Contaminant Name	Population Exposed (of 3,441,376 Total)		Number of Water Systems (of 1,146) Total
		At Any Level	Above Health Limits See Note	With Detected	Above Health Limits See Note
1	Nitrate & nitrite	2,265,287	12,598	526	10
		Chemical that enters water from fertilizer runoff, leaching septic tanks, and erosion of natural deposits
2	Total trihalomethanes (TTHMs)	2,695,477	1,939,087	356	217
		Measure of four disinfection by-products
3	Gross beta particle activity (pCi/L)	1,635,769	0	325	0
		Mainly pollutants from nuclear testing and industrial and medical instruments
4	Alpha particle activity	1,635,581	5,571	323	7
		From mining waste polluants and natural sources
5	Dibromochloromethane	2,263,653	1,561,032	308	255
		Disinfection by-product
6	Bromodichloromethane	2,572,852	1,969,487	294	243
		Disinfection by-product
7	Chloroform	2,565,248	1,808,012	290	178
		Disinfection by-product
8	Bromoform	1,437,003	116,649	195	23
		Disinfection by-product
9	Copper	294,490	12,541	181	11
		contaminant that enters water by corrosion of household plumbing systems; erosion of natural deposits
10	Nitrate	122,097	397	48	2
		Chemical that enters water from fertilizer runoff, leaching septic tanks, and erosion of natural deposits

View Full Table

NOTE: Health based limits included in this analysis include enforceable drinking water limits (called Maximum Contaminant Limits, or MCLs) as well as governmental, non-enforceable health guidelines, such as Maximum Contaminant Limit Goals (MCLGs), lifetime health advisory levels, one-day and ten-day advisory levels to protect children from non-cancer health endpoints, and other government-established health guidelines for tap water contaminants.

Testing Summary

The federal government has set standards for some of the pollutants found in tap water supplies.

Contaminants reported as tested by water suppliers in Oklahoma		129
	Contaminants tested due to federal law:	84
	Contaminants tested in addition to those required by federal law:	45

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Violations Summary

According to EPA, in 2003 6% of America's public water systems reported one or more violations of a health-based drinking water standard, and 26% reported significant violations of either monitoring and reporting requirements or health-based standards.

Reported violations (1998 - 2003): 4,136

Number of OK systems with violations: 852 (74.3%)

[View Details]

Information on violations is drawn directly from EPA's national violations database in the Agency's Safe Drinking Water Information System. Analyses by others have raised questions about the quality of the information in EPA's database. For the purposes of this investigation, EWG is not showing below or including in our analyses, those violations for individual water suppliers that occurred on days for which the total number of violations assigned by EPA to that water supplier was greater than 20. This criteria was based on common characteristics of incorrect violations data as identified by water utilities, from a review of EPA's violations data by several hundred utilities prior to the release of EWG's investigation.