EWG Investigation | U.S. Tap Water Quality Database

Health Limit Exceeded
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Legal Limit
• EPA set legal limit which balances health concerns and treatment costs

Tier 3 Control - past mining and drilling
• Closed or abandoned mines/plans/notices
• Mineral rich land that has been titled to mining interests (mining patents)
• Formerly drilled and pumped oil & gas Leases

EWG INVESTIGATION

Findings

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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 Delaware
281 Water Systems
Serving 804,128 People

An Environmental Working Group analysis of tap water tests from 1998 through 2003 for 281 communities across Delaware shows 70 pollutants were found in drinking water across the state.

Pollution Summary

70	Total Contaminants Detected (1998 - 2003)
13	Agricultural Pollutants (pesticides, fertilizer, factory farms) Nitrate & nitrite, Nitrate, Nitrite, Phosphate, Sulfate, Thallium (total), Heptachlor, Endosulfan I, Dieldrin, Bromomethane, Chlordane, Ethylbenzene, Alpha Chlordane
19	Sprawl and Urban Pollutants (road runoff, lawn pesticides, human waste) Arsenic (total), Cadmium (total), Copper, Lead (total), Mercury (total inorganic), Nitrate & nitrite, Nitrate, Nitrite, Phosphate, Antimony (total), Trichlorofluoromethane, Acetone, MTBE, Diethylphthalate, Di-n-butylphthalate, Xylenes (total), Tetrachloroethylene, Benzene, o-Xylene
53	Industrial Pollutants Aluminum, Arsenic (total), Barium (total), Cadmium (total), Chromium (total), Cyanide, Lead (total), Manganese, Mercury (total inorganic), Nitrate & nitrite, Nitrate, Nitrite, Phosphate, Selenium (total), Sulfate, Antimony (total), Beryllium (total), Thallium (total), p-Isopropyltoluene, Di(2-ethylhexyl) phthalate, Endosulfan I, Chloromethane, Dichlorodifluoromethane, Bromomethane, Chloroethane, Trichlorofluoromethane, Acetone, Methyl isobutyl ketone, MTBE, Tetrahydrofuran, Diethylphthalate, Di-n-butylphthalate, cis-1,2-Dichloroethylene, 2,2-Dichloropropane, Xylenes (total), Dichloromethane (methylene chloride), o-Chlorotoluene, p-Chlorotoluene, 1,1-Dichloroethylene, 1,1-Dichloroethane, 1,2-Dichloroethane, 1,1,1-Trichloroethane, Carbon tetrachloride, 1,2-Dichloropropane, Trichloroethylene, 1,1,2-Trichloroethane, Tetrachloroethylene, Benzene, Toluene, Ethylbenzene, Styrene, o-Xylene, m- & p- Xylene
15	Water Treatment and Distribution Byproducts (pipes and fixtures, treatment chemicals and byproducts) Cadmium (total), Di(2-ethylhexyl) phthalate, Chloromethane, Monochloroacetic acid, Dichloroacetic acid, Trichloroacetic acid, Monobromoacetic acid, Dibromoacetic acid, Bromochloroacetic acid, Total haloacetic acids, Chloroform, Bromoform, Bromodichloromethane, Dibromochloromethane, Total trihalomethanes (TTHMs)
14	Naturally Occurring (naturally present but increased for lands denuded by sprawl, agriculture, or industrial development) Aluminum, Arsenic (total), Chromium (total), Copper, Lead (total), Manganese, Mercury (total inorganic), Nitrate & nitrite, Nitrate, Nitrite, Phosphate, Selenium (total), Sulfate, Chloromethane
21	Unregulated Contaminants EPA has not established a maximum legal limit in tapwater for these contaminants Phosphate, p-Isopropyltoluene, Endosulfan I, Dieldrin, Chloromethane, Dichlorodifluoromethane, Bromomethane, Chloroethane, Trichlorofluoromethane, Acetone, Methyl isobutyl ketone, MTBE, Tetrahydrofuran, Diethylphthalate, Di-n-butylphthalate, 2,2-Dichloropropane, Bromochloroacetic acid, o-Chlorotoluene, p-Chlorotoluene, 1,1-Dichloroethane, Alpha Chlordane

70 33
13 7
19 9
53 20
15 11
14 8
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): 70

Total population exposed above health-based limits: 561,982

Communities served water with contaminants above health-based limits: 61

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: 33

Rank Contaminant Name Population Exposed (of 804,128 Total) Number of Water Systems (of 281) Total
At Any Level Above Health Limits
See Note With Detected Above Health Limits
See Note
1 Nitrate 723,059 37,550 125 10
Chemical that enters water from fertilizer runoff, leaching septic tanks, and erosion of natural deposits
2 Sulfate 559,187 0 77 0
Substance from natural deposits, industrial processes, and agriculture
3 Chloroform 583,255 527,283 53 18
Disinfection by-product
4 Bromodichloromethane 554,306 550,857 42 36
Disinfection by-product
5 Dibromochloromethane 539,650 514,974 39 30
Disinfection by-product
6 Total trihalomethanes (TTHMs) 537,269 488,011 35 13
Measure of four disinfection by-products
7 Nitrate & nitrite 289,143 107 21 1
Chemical that enters water from fertilizer runoff, leaching septic tanks, and erosion of natural deposits
8 Manganese 217,114 339 19 2
element from natural deposits as well as industrial use
9 Arsenic (total) 221,158 221,158 18 18
Metal that enters water by erosion of natural deposits, runoff from glass and electronics processing
10 Barium (total) 216,750 200,000 16 1
Mineral from drilling and mining waste runoff; erosion of natrual deposits

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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 Delaware 191

Contaminants tested due to federal law: 79

Contaminants tested in addition to those required by federal law: 112

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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): 418

Number of DE systems with violations: 173 (61.6%)

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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.