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E. coli water tests found inconsistent

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COLUMBUS, Ohio, Dec 07, 2004 (United Press International via COMTEX) -- Standard testing methods for the E. Coli bacteria in water proved less accurate than reported in tests conducted by the U.S. Geological survey.

The USGS-led study was done in cooperation with state and local government agencies and several universities and affiliated consultants. It was among the first to test the accuracy of microbial source tracking methods against samples of known origin, called "challenge isolates."

Scientists compared the accuracy of several source tracking tools in classifying E. coli strains to sources including humans, dogs, geese, deer, horses, pigs, cows and chickens.

When researchers sent E. coli challenge isolates for testing, many isolates either remained unclassified or were classified to incorrect sources. In all, fewer than 30 percent of challenge isolates were classified to the correct source-animal species by any method.

However, prior source tracking research reports accuracy ranges from 60 percent to 90 percent for various source tracking methods.

The report is published in the journal Environmental Science and Technology.

Copyright 2004 by United Press International.


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