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EPA: some water samples from Saginaw, Midland and Bay City unusable due to lab contamination; retesting for furans to begin

Release Date: 10/05/2009
Contact Information: Mick Hans, 312-353-5050,

No. 09-OPA192

(CHICAGO - Oct. 5, 2009) U.S. Environmental Protection Agency Region 5 said today that the results of some samples from the Midland, Saginaw and Bay City, Mich., water supply systems taken last July are faulty due to laboratory contamination. Test results showed low levels of furans in EPA's water samples. However, because the furans were also detected at similar concentrations in clean blank reference samples, EPA scientists quickly realized these results were actually caused by lab contamination. Since the results are unusable, EPA has contacted the cities to schedule a new round of sampling later this week.

After reviewing the situation with SGS North America-the company whose lab analyzed the results-it was confirmed that EPA's water samples were contaminated by furans in the lab equipment. SGS has since modified its equipment and processed a new, clean blank reference sample. This sample did not detect any furans.

"EPA has extensive quality control procedures in place to catch analytical problems and this case proves they are effective," said Acting Regional Administrator Bharat Mathur.

EPA collected the samples in response to community questions about impacts to drinking water from contaminated sediment stirred up by U.S. Army Corps of Engineers' navigational dredging in the Saginaw River. Dioxins and furans are byproducts of historical industrial processes by the Midland-based Dow Chemical Co.

This past July 28-29, EPA contractors Weston Solutions collected samples from both the intakes and from treated water for the Saginaw, Midland and the Bay City water supply systems. The samples were then processed by Weston's subcontractor, SGS North America (Wilmington, N.C.), which operates a laboratory certified to analyze dioxin and furans. More sampling is planned for spring 2010, when USACE dredging is expected to resume.

The EPA water sampling tested for more than 120 other chemicals. The results for these other chemicals, analyzed at a different lab, were below EPA's maximum contaminant levels which ensure municipal drinking water supplies are safe. The complete report will be posted by Wednesday on EPA's Web site:

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