MADISON , Wisconsin , January 20, 2003 (ENS) - Researchers in the U.S. and Pakistan have identified a group of microorganisms that can break down a common toxic pesticide, endosulfan.

Detoxifying pesticides through biological means is receiving attention as an alternative to existing methods, such as incineration and landfill, which are not sufficient for large, contaminated sites. Researchers from the University of California at Riverside and the University of Agriculture , Faisalabad , Pakistan , have identified specific microorganisms, which can breakdown the toxicity of endosulfan. By identifying microorganisms to degrade endosulfan, these researchers were able to reduce the toxic residues in the soil. The results of this study are published in the January-February issue of the "Journal of Environmental Quality."

"Pollutants can be degraded by microorganisms when they use the toxin as a carbon and energy source," said project leader William Frankenberger of UC-Riverside. "We have been successful in isolating two strains that have immense potential for endosulfan degradation." Endosulfan, classified as an organochlorine - the same family as DDT - is registered for use as a pesticide on 60 U.S. crops. Its residues have been found in the atmosphere, soils, sediments, surface and ground waters, and food.

It is one of the most commonly detected pesticides in U.S. water, found in at least 38 states, and is rated by the U.S. Environmental Protection Agency as a Category 1 pesticide with "extremely high acute toxicity." Endosulfan affects the central nervous system, kidney, liver, blood chemistry and parathyroid gland and has reproductive, teratogenic and mutagenic effects. Total average annual use of endosulfan is estimated at about 1.38 million pounds of the active ingredient. Endosulfan and its breakdown products are persistent in the environment, entering the air, water, and soil during the pesticide's use and manufacture.

The results of this work suggest these novel strains of microorganisms are a valuable source of endosulfan degrading enzymes and may be used for the detoxification of endosulfan in contaminated soils, wastedumps, water bodies, industrial effluents and unused or expired stockpiles of the pesticide.

Source: (AmeriScan: January 20, 2003 - Environment News Service)