Gasoline Range Organic Test Suspect

November 14, 2008
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Test results returned on independent samples taken by Headwaters Inc. in the aftermath of a petroleum release into the river at Whitesburg show a detection for gasoline range organics in both the river water downstream of the contamination site, and tap water from six of seven sites sampled. The test results can be found on our web site at www.letcherwater.com/datareports.html

The tests may be suspect, however. McCoy and McCoy Laboratories, which supplied the sampling bottles for the testing, now says the bottles were not the correct type for collecting samples for Gasoline Range Organics analysis, and may have made the results inaccurate.

The lab report speculates that the detection in treated samples may indicate trihalomethanes, chemicals that result as byproducts of water disinfection. Trihalomethanes include chloroform, bromodichloromethane, dibromochloromethane, and bromoform, and are formed by reactions between chlorine-based disinfectants used to treat water and organic and inorganic chemicals found in the raw water.

Two of the samples showed gasoline range organic detections in untreated water taken from the North Fork of the Kentucky River about 100 yards below the contamination site (upstream of the Whitesburg water treatment plant) and from the North Fork just upstream of the Blackey water treatment plant several miles away. Trihalomethanes should not be found in river water unless the samples are taken downstream of a treatment plant during backwashing operations, a person familiar with treated water testing said. The lab report does not mention THMs in connection with those samples. Samples taken from upstream of the contamination and from an outdoor tap at Letcher County Central High School do not show any detections.

Taps in six locations in the county and city water systems did show detections for gasoline range organics, all of which the lab attributed to trihalomethanes.

Headwaters and the Sierra Club, which paid for the sampling, plan to retest for gasoline once we and the laboratory agree on the type of bottles and the procedure required. The gasoline range organics test cannot be matched to EPA drinking water standards because the gas chromatograph test used by the laboratory reveals only a broad range of straight-chain hydrocarbons found in gasoline, not individual chemicals.

Posted by Sam

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