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EWG INVESTIGATION

 

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EWG Statement, 03/10/2008

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National Contaminants of Concern

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RankContaminant NamePopulation Exposed
(of 231,439,195)
Number of Water Systems
(of 39,751)
Number
of States
with Detections

(of 42)
At Any LevelAbove Health Limits
See Note
At Any LevelAbove Health Limits
See Note
1Total trihalomethanes (TTHMs)
Regulated
170,113,651116,265,46214,6756,97539
Measure of four disinfection by-products 
2Nitrate
Regulated
164,806,73012,390,27922,36365731
Chemical that enters water from fertilizer runoff, leaching septic tanks, and erosion of natural deposits 
3Chloroform
Regulated
153,506,94578,454,76011,3694,13438
Disinfection by-product 
4Bromodichloromethane
Regulated
147,485,443115,218,8329,9667,29838
Disinfection by-product 
5Dibromochloromethane
Regulated
139,104,583100,373,4859,4437,00538
Disinfection by-product 
6Barium (total)
Regulated
134,841,413827,08018,83517729
Mineral from drilling and mining waste runoff; erosion of natrual deposits 
7Bromoform
Regulated
99,694,2364,363,9436,14072634
Disinfection by-product 
8Arsenic (total)
Regulated
90,097,38490,096,0569,9579,95638
Metal that enters water by erosion of natural deposits, runoff from glass and electronics processing 
9Copper
Regulated
77,074,6224,398,11212,1691,40229
contaminant that enters water by corrosion of household plumbing systems; erosion of natural deposits 
10Total haloacetic acids
Regulated
69,077,84120,251,5822,79193527
Measure of disinfection by-products; refers to the sum of the concentrations of dichloroacetic acid, trichloroacetic acid, monochloroacetic acid, monobromoacetic acid and dibromoacetic acid in a water sample. 
11Nitrate & nitrite
Regulated
66,875,947116,2837,5269715
Chemical that enters water from fertilizer runoff, leaching septic tanks, and erosion of natural deposits 
12Alpha particle activity
Regulated
66,388,504691,8926,63231913
From mining waste polluants and natural sources 
13Manganese
Regulated
59,746,3856,089,9148,1822,27328
element from natural deposits as well as industrial use 
14Lead (total)
Regulated
50,382,9869,619,7837,9422,27533
Metal that enters water by corrosion of household plumbing systems; industrial pollutant; erosion of natural deposits 
15Aluminum
Regulated
47,160,552695,2552,5708913
Metal from metal refineries and mining operations 
16Alpha particle activity (excl radon and uranium)
Regulated
36,052,637296,1696,29621915
From mining waste pollutants and natural sources 
17Trichloroacetic acid
Regulated
35,501,0452,023,7321,68925315
Disinfection by-product 
18Radon
Unregulated
34,833,41612,434,4781,21587916
natural (radioactive) breakdown product of uranium in soil, rock and water 
19Selenium (total)
Regulated
32,638,4232,184,7222,431397
Metal from mining or petrolum refining pollution; erosion of natural deposits 
20Nitrite
Regulated
28,587,707707,9752,7228722
Chemical that enters water from fertilizer runoff, leaching septic tanks, and erosion of natural deposits 

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