The Study Of Toxic Effect Of Dimethoate And Triazophos On Tadpoles Of Two Anuran Species

In the study, two kinds of organophosphate pesticides: Dimethoate and Triazophos were selected as the pollutants, and tadpoles of two anuran species: Bufo melanostictus and Polypedates megacephalus were chosen to be the experimental animals. The study focused on the acute toxicity, the sub-chronic toxicity, genotoxicity and histiocytic detecting to evaluate the toxicity effects of two organophosphate pesticides on the two kinds of tadpoles. The purpose is to discuss the target positions about the toxicity effects of the pesticides on the amphibian synthetically and constitutionally and provide the scientific proofs for the amphibian as well. Besides, it can help choose the suitable animals for research and select the sensitively biological markers which will be useful to build the system of environmental monitoring for water ecosystem depending on the amphibian.The acute toxicity test was used to study the effects of Dimethoate and Triazophos on Bufo melanostictus tadpoles. The purpose was to observe how the chemical substances acting and find the relations of dose-effect. Then the toxicity information could be gained for water-quality monitoring. In the sub-chronic toxicity test, the effects of two pesticides on the growth rate of Bufo melanostictus tadpoles were measured to study whether two pesticides presented the cumulative toxicity action. In the genotoxicity test, micronuclei were measured after the tadpoles of Bufo melanostictus and Polypedates megacephalus exposed to two pesticides for 5days and 7days respectively. Furthermore, single cell gel electrophoresis experiment (SCGE) was used to study the relation of DNA damage and two pesticides when the different stages of tadpoles of both Bufo melanostictus and Polypedates megacephalus were treated with the pollutants. Lastly, after TUNEL labeling, the apoptosis index of liver, intestine, tail base and ovary of Bufo melanostictus tadpoles was calculated after exposed to two pesticides for some time.By means of the acute toxicity test, the results showed that the toxicity of Dimethoate to Bufo melanostictus tadpoles was low and Triazophos was medium. The sub-chronic toxicity test showed two pesticides could retard the daily growth rate of body length of Bufo melanostictus tadpoles. Also by detecting the DNA damage and inducement of micronuclei, it was resulted two pesticides were hurtful to tadpoles of both Bufo melanostictus and Polypedates megacephalus. It was observed that two pesticides...