Risk Assessment Of Diazinon On Birds

This thesis studied the environment risks of diazinon to birds through acute toxicity test and monitor of field test and model predict.On such a basis,the results of the thesis would help to formulate safe application standard of diazinon.The acute oral toxicity and dietary toxicity of 95%diazinon technical and 50%diazinon EC and 10%diazinon GR to birds was determined in laboratory.The field test was carried out to study the effects of diazinon to birds when 50%diazinon EC was used to seed coating.Results of acute oral toxicity test showed that the LD₅₀ of 50%diazinon EC to Japanese quail and partridge are 4.61 mg/kg body and 32.01 mg/kg body respectively, 50%diazinon EC is drastic toxicity to Japanese quail and high toxicity to partridge.The LD₅₀ of 95%diazinon technical to Japanese quail and partridge are 13.9 mg/kg body and 22.39 mg/kg body respectively.The toxicity ranks of 50%diazinon EC to Japanese quail and partridge belongs to high risk.The LD₅₀ of 10%diazinon GR to Japanese quail and partridge are 13.9 mg/kg body and 22.39 mg/kg body respectively. The toxicity ranks of 10%diazinon GR to Japanese quail drastic and to partridge belongs to high risk.The results of dietary toxicity test showed that the LC₅₀ of 50%diazinon EC to Japanese quail is 120 mg/kg food,the dietary toxicity rank is high;the the LC₅₀ of 50% diazinon EC to partridge is 1210 mg/kg food,the dietary toxicity rank is low.The fact effects of diazinon on birds was studied through field test.In field test, 50%diazinon EC as seed coating.The study methods we used include continuous monitor and fowling and manual finding dead birds.Field test results indicated that there were no fact effects in this special field test conditions.A study on the degradation of diazinon in seeds sampling from field was completed.The result showed that diazinon was degraded easily in seeds,the half-lifes of diazinon in seeds is 1.87d.Due to the rapid degradation of diazinon in field,it reduced the risks of diazinon to birds greatly,captured.Within Eighty-eight birds captured birds,12 birds were found that there were seeds in stomach and craw.Seeds were sampling from the 12 birds to detect the diazinon.The result showed that eight samples have diazinon, the maximum detectable is 952μg.At the same time,we sampling brains of the 12 birds found seeds in stomach to determine the AchE activity.Compared with control birds,the highest droop rate of AchE activity is 22.3%.Commonly,it can cause dead affairs when droop rate of AchE activity is superior to 40%.According to its toxicity,diazinon is easily to do harm to birds when used as seeds coating.Study results of overseas indicated that dead affairs of birds caused by diazinon usually happened in fields.The fact effects of pesticides on birds are affected by lots of factors,such as weather and instruction and formulation.In our field test,it happened to rain,so the results were affected seriously.In a word,diazinon is high risk to birds,we should strengthen the management of diazinon.