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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 Colorado 843 Water Systems Serving 4,949,571 People

An Environmental Working Group analysis of tap water tests from 1998 through 2003 for 843 communities across Colorado shows 72 pollutants were found in drinking water across the state.

Pollution Summary

72 37	15 9	14 9	56 25	12 8	18 16
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): 72

Total population exposed above health-based limits: 4,104,241

Communities served water with contaminants above health-based limits: 510

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: 37

Rank	Contaminant Name	Population Exposed (of 4,949,571 Total)		Number of Water Systems (of 843) Total
		At Any Level	Above Health Limits See Note	With Detected	Above Health Limits See Note
1	Nitrate & nitrite	3,744,823	3,247	649	5
		Chemical that enters water from fertilizer runoff, leaching septic tanks, and erosion of natural deposits
2	Sulfate	4,177,822	0	518	0
		Substance from natural deposits, industrial processes, and agriculture
3	Alpha particle activity (excl radon and uranium)	2,402,351	4,145	517	15
		From mining waste pollutants and natural sources
4	Gross beta particle activity (pCi/L)	3,520,085	0	502	0
		Mainly pollutants from nuclear testing and industrial and medical instruments
5	Total trihalomethanes (TTHMs)	4,046,229	3,526,470	448	211
		Measure of four disinfection by-products
6	Nitrate	3,292,966	6,218	429	8
		Chemical that enters water from fertilizer runoff, leaching septic tanks, and erosion of natural deposits
7	Chloroform	3,951,942	3,340,221	362	130
		Disinfection by-product
8	Copper	3,367,655	5,538	351	10
		contaminant that enters water by corrosion of household plumbing systems; erosion of natural deposits
9	Bromodichloromethane	3,894,330	3,745,136	349	257
		Disinfection by-product
10	Dibromochloromethane	3,128,904	2,724,183	292	221
		Disinfection by-product

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 Colorado		120
	Contaminants tested due to federal law:	75
	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): 2,271

Number of CO systems with violations: 487 (57.8%)

[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.