毒死蜱、马拉硫磷和氰戊菊酯对赤子爱胜蚓（Eisenia foetida）的急性毒性

采用滤纸接触法和土壤培养法研究了毒死蜱(Chlorpyrifos)、马拉硫磷(Malathion)和氰戊菊酯(Fenvalerate)对赤子爱胜蚓(Eisenia foetida)的急性毒性效应.滤纸接触法试验浓度分别设置为,毒死蜱:3.14、6.28、9.42、12.56、15.70、18.84μg·cm-2;马拉硫磷:3.10、6.20、12.40、18.60、24.80、31.40μg·cm-2;氰戊菊酯:0.31、0.62、1.24、1.86、2.48、3.14μg·cm-2.土壤培养法试验浓度分别设置为,毒死蜱:100、125、150、175、200、225、250mg·kg-1;马拉硫磷:350、400、450、500、550、600mg·kg-1;氰戊菊酯:20、30、40、50、60、70、80mg·kg-1.结果表明:采用滤纸接触法测得的各农药对蚯蚓48h的半数致死浓度(LC50)分别为毒死蜱12.26μg·cm-2、马拉硫磷19.61μg·cm-2、氰戊菊酯1.03μg·cm-2;采用土壤培养法测得的各农药对蚯蚓7d的LC50分别为毒死蜱427.67mg·kg-1、马拉硫磷742.53mg·kg-1、氰戊菊酯81.81mg·kg-1,14d的LC50分别为毒死蜱182.21mg·kg-1、马拉硫磷497.29mg·kg-1、氰戊菊酯37.46mg·kg-1.根据《化学农药环境安全评价试验准则》,这3种农药对蚯蚓的毒性均为低毒级.

Acute Toxicological Dosages of Chlorpyrifos, Malathion and Fenvalerate on Earthworm Eisenia foetida

Pesticides are important environmental pollutants in soil. They may have significant effects on earthworms that play an important part in transformation of soil nutrients. In this study, we measured acute toxicological dosages of three pesticides of chlorpyrifos, malathion and fenvalerate on earthworm Eisenia foetida by using filter paper contacting method and natural soil method. The concentration gradients in filter paper contacting method were 3.14, 6.28, 9.42, 12.56, 15.70, 18.84μg·cm -2 (chlorpyrifos); 3.10, 6.20, 12.40, 18.60, 24.80, 31.40μg·cm -2 (malathion); 0.31, 0.62, 1.24, 1.86, 2.48, 3.14μg·cm-2 (fenvalerate). The concentration gradients in natural soil method were 100, 125, 150, 175, 200, 225, 250mg·kg-1(chlorpyrifos); 350, 400, 450, 500, 550, 600mg·kg-1(malathion); 20, 30, 40, 50, 60, 70, 80mg·kg -1 (fenvalerate). Results showed that the 48h LC50 values of chlorpyrifos, malathion and fenvalerate for earthworm using filter paper contacting method were 12.26, 19.61 and 1.03μg·cm-2, respectively. Using natural soil method, the 7d LC50 values of chlorpyrifos, malathion and fenvalerate for earthworm were 427.67, 742.53 and 81.81mg·kg -1, respectively, and 14d LC50 values were 182.21, 497.29 and 37.46mg·kg -1. According to the Experimental Criterion for Environmental Safety Assessment of Chemical Pesticide, chlorpyrifos, malathion and fenvalerate are low toxicity to earthworm.