A new study shows that many widely used pesticides can cause unpredictable damage to wildlife, such as degeneration. The chemical substances contained in these insecticides are usually chiral, which means that their structure is the same, but they are mirror images of each other. Scientists working on the research found that chemical compounds that are structurally chiral have a "dramatic difference" in toxicity and duration, and they believe that managers need to consider chirality when assessing the risks of using pesticides. in principle. Although a molecule has similar chemical properties to its mirror version, or its corresponding isomer, its reaction with the enzyme is different. Researchers noticed 10 years ago that bacteria tend to preferentially break down residual pesticides with specific counterparts, such as dichlorodiphenyltrichloroethane (DDT), and other contaminants, so that pesticides with a corresponding structure ratio Slanted in some food chains. The researchers also found that the toxicity of the counterparts can be changed, however, most of the research work is conducted against banned chemicals. Jay Gan, a chemist at the University of California at Riverside, and his colleagues recently conducted research on widely used pesticides. The researchers analyzed five common insecticides, including organophosphate pesticides such as profenofos, and pyrethroid pesticides such as permethrin. For a small crustacean named Daphia, which is commonly used to assess toxicity, one of these insecticides is at least 10 times more toxic than other chemicals. The researchers also found that the corresponding isomers of the two organophosphate pesticides have different residence times in sediments. They reported on the online version of the "Journal of the National Academy of Sciences" on January 3, 2005, that the content of one of the corresponding isomers of permethrin reached twice the amount of other chemicals in one year. The research team believes that this result shows that the impact of certain pesticides on the environment mainly depends on the nature of a particular counterpart. Gan said, "The results of these chemicals in risk assessment are different, so the formulation of laws and regulations also needs to be more stringent." Derdk Muir of the National Institute of Water Research, Buelington, Canada, agreed. He believes that changes in isomers play an important role in the determination of ecotoxicity. He said that "selective degradation is very important for assessing the toxicity of pesticides on organisms." Charles Wong, an environmental chemist at the University of Alberta in Edmonton, Canada, believes that if managers don't consider changes in the ratio of corresponding isomers and their respective toxicities, they will not be able to grasp the real situation.
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