GENOTOXICOLOGICAL STUDIES OF TWO PESTICIDES TO TADPOLES AND FROGS OF RANA NIGRINACULATA HALLOWEII BY MICRONUCLEI TEST AND SINGLE CELL GEL ELECTROPHORESIS ASSAY

Imidacloprid 1-(6-chloro-3-pyridylmethyl)-N-n itro-imidazolidin-2-ylid eneamine and RH-58492'-benzoyll'-tert-butylbenzoylhydrazinelare two novel pesticides being used in China. Imidacloprid, which act as an agonist at t he nicotinic acetylcholine receptor,is highly effective against many sucking insects including ricehoppers, aphids, thrips and white flies. RH-5849, a nonsteroida l ecdysone agonist, which act similar to 20-hydroxyecdysone by binding to the ecdosone receptor, have been found to be very effective against lepidopteran pests in vegetables, cotton, and cereals. To our knowledge, their effects on the aqu atic and agricultural ecosystems have not been fully investigated. Amphibians ar e important organisms in the aquatic and agricultural ecosystems; they are among the most important natural enemies of many agricultural pests. Because of their sensitivity to changes of their habiat and that their larvae live in the aquat ic environment, the amphibians were regarded as bio-indicators of aquatic and a gricultural ecosystems, and broadly used as typical test organisms in evaluating the effects of chemicals on the aquatic and agricultural ecosystems. This study was initiated to combine micronucleus test (MN) and comet assay to assess the genotoxicity of the two pesticides on the amphibians from different endpoints. Th e objective was to achieve a more comprehensive understanding of the effects and potential risks of the pesticides on the aquatic and agricultural ecosystems.