Eco-toxicity Evaluation Of Triadimefon To Soil Fauna And Flora

Triadimefon （TDM）, a kind of triazole fungicides which created in the1970s, is widelyused in terms of controlling disease and improving production in agriculture, as well as a kindof medicine in clinical area for anti-depression of nervous system. With the rapiddevelopment of economy and technology, the application range of TDM in disease controlgradually extended from singly for wheat to widely for fruits, vegetables, herbs and all kindsof agricultural cultivation. In recent years, the study in TDM is mostly foucs on residuedetection and degradation mechanism, but less on toxicity. The current researches are mainlyconcerned about the effect of TDM to individuals, but seldom on the molecular level.The object of this work is to detect the inhibition effect of TDM to seed germination androot elongation of6kinds of crops, to test the acute toxicity effect to Eisenia foetida, and toidentify the genotoxic effect by using micronucleus test on wheat root tip cells and the cometassay on cells of Eisenia foetida, through these assays the ecotoxicity of TDM to the soilecosystem has been evaluated. The main conclusions are as follows:1. The sensitivity of the germination rate of different crops to TDM is different, and itwas showed that the sensitivity of fibrous root system crops were stronger than the tap rootsystem crops. The dose-response relationship of germination index of different crops toTDM is in the same manner, when the concentration is increasing, the inhibition effect isincreasing.2. The medium lethal concentration （EC50） of TDM to root elongation was as follows:Cucumis sativus,61.6mg·L^-1; Brassica chinensis,88.7mg·L^-1; Mung bean,211.7mg·L^-1;Paddy rich,39.5mg·L^-1; Wheat,62.5mg·L^-1; Sorghum,95.7mg·L^-1. It was showed that thesensitivity of root elongation to TDM in fibrous root system crops were stronger than that inthe tap root system crops, and TDM is easy to exert toxic damage on fibrous root systemcrops.3. Micronucleus was appeared in a certain range of TDM concentration; highconcentration of TDM induced metabolites retentate increasing in cells. There was no clearlytoxic effect of TDM at concentration of20mg·L^-1to Eisenia foetida. LC50of TDM to Eiseniafoetida was167.6,54.9and37.5mg·L^-1at24,48and72h, respectively.4. With the rising of TDM concentration, the rate of tailing cells and the lengthes ofcomet tails of cells have a obviously increased, presenting a relationship between degree ofdamage and concentration.The concentration of TDM in practical applications is200mg L^-1suggested by the manufacturer, form our experimental results, this concentration was not only larger than theLC50of TDM on the germination and growth of crops seeds, but also than that on the growthand genetic integrity of soil animals. Thus, TDM will have strong negative potential effectsthat inducing chromosome aberration and damage of DNA under high concentration.Therefore, we should take the method of applying more times at low concentration todecrease the harm of TDM on the soil ecosystem and the environment, reduce the threat tohuman health.