EWG INVESTIGATION

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EWG Statement, 03/10/2008

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

Dichloroiodomethane is an unregulated by-product of tap water disinfection and an EPA top priority for testing and study based on toxicity concerns. No information on potential health impacts for Dichloroiodomethane was identified in standard government and academic sources.

Sources of Dichloroiodomethane:

Water Treatment and Distribution Byproducts (pipes and fixtures, treatment chemicals and byproducts)

An Environmental Working Group analysis of Dichloroiodomethane tests reported by 12 public water suppliers in 2 states shows that between 1999 and 2002, 122 thousand people in 9 communities drank water contaminated with Dichloroiodomethane. No health-based limit has been established by the federal government.Dichloroiodomethane remains unregulated in tap water, without a maximum legal limit.

Exposure Summary

121,763 People drinking water contaminated with Dichloroiodomethane 9 Communities served water contaminated with Dichloroiodomethane

Table. Dichloroiodomethane Exposure by State

122 thousand Americans in 1 states were served tap water contaminated with Dichloroiodomethane between 1999 and 2002.

State	Water suppliers with Dichloroiodomethane contamination
	Systems	Population
Texas	9	121,763
Total	9	121,763

Table. The most polluted communities

122,000 Americans in 9 communities were served tap water contaminated with Dichloroiodomethane between 1999 and 2002

Ranked by highest average Dichloroiodomethane level

Rank	System	Population Served	Positive test results of total reported tests	Average Level (Range)
1	City of Jacksonville Jacksonville, TX	14,325	2 of 2	4.5 ppb (3.3 to 5.7 ppb)
2	City of Longview Water Longview, TX	77,271	1 of 1	2.1 ppb (2.1 to 2.1 ppb)
3	City of Gladewater Gladewater, TX	6,085	2 of 2	1.65 ppb (1.5 to 1.8 ppb)
4	City of West Tawakoni West Tawakoni, TX	3,561	1 of 1	1.6 ppb (1.6 to 1.6 ppb)
5	North Texas Mwd WYLIE, TX	200	1 of 1	1.5 ppb (1.5 to 1.5 ppb)
6	River Bend Water Services Inc. Matagorda, TX	120	2 of 2	1.35 ppb (1.1 to 1.6 ppb)
7	City of Ennis Ennis, TX	17,450	1 of 1	1.2 ppb (1.2 to 1.2 ppb)
8	City of Kemp Kemp, TX	2,403	1 of 1	1.1 ppb (1.1 to 1.1 ppb)
9	Caney Creek Haven Club Water System Sargent, TX	348	1 of 1	1.1 ppb (1.1 to 1.1 ppb)

Testing Summary for Dichloroiodomethane

Water suppliers report an average of 0.3 Dichloroiodomethane tests per year. 39,739 water suppliers failed to report any Dichloroiodomethane tests at all.

Are tests routinely required for Dichloroiodomethane by federal law? No Water suppliers reporting tests for Dichloroiodomethane (1999-2002): 12 of 39,751 Average testing rate for water supplier reporting tests (1999-2002): 0.3 per year

Dichloroiodomethane Violations

Because Dichloroiodomethane 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 Dichloroiodomethane, and any level is legal in tap water.