甲胺磷、乙草胺和铜单一与复合污染对蚯蚓的毒性效应研究

Single and binary-combined toxicity of methamidophos, acetochlor and Cu on earthworm Eisenia foetida

以赤子爱胜蚓 (Eiseniafoetida)为例 ,通过滤纸急性毒性试验法研究了东北黑土区普遍存在的 3种农用化学品甲胺磷、乙草胺和Cu对蚯蚓的单一与复合毒性效应 .单一实验结果表明 ,三者对蚯蚓均有毒性 ,它们的毒性顺序为乙草胺 >甲胺磷 >Cu ,半致死浓度分别为 :0 .30 7、0 .70 8和 118.70mg·kg-1;同时通过观察可知 ,乙草胺与Cu以皮肤渗入蚯蚓体的毒性效应较甲胺磷明显 .复合毒性实验结果表明 ,低浓度Cu与高浓度Cu对甲胺磷的毒性均有增强作用 ;低浓度Cu对乙草胺的毒性有削弱作用 ,但高浓度Cu对乙草胺的毒性有增强作用 .可见 ,三者对土壤生态系统生态安全性和土壤健康质量存在潜在危害 ,同时这几种污染物的共存进一步加大了潜在危害性 ,且复合毒性效应与各组浓度组合密切相关 .

A population of earthworm Eisenia foetida was exposed to single and binary-combined contamination of phaeozem by methamidophos, acetochlor and Cu. The result showed that one of three test chemicals had its toxicity on the earthworm population,and the single toxic sequence of the chemicals was acetochlor > methamidophos > Cu.The values of their LD 50 were 0.307, 0.708 and 118.70 mg·kg -1, respectively. The difference was depended on the biological mechanisms of the earthworm population.Acetochlor and Cu in soil could be absorbed by the earthworm population through penetrating through the skin of an earthworm.The result also showed that Cu could swell the toxicity of methamidophos,whether it was in low or high concentration by the binary-combined toxic effect test.Cu in low concentration could decrease the toxicity of acetochlor, but in high concentration ,Cu could increase the acetochlor toxicity in soil. Therefore ,these three pollutants were dangerous to the ecological security of soil ecosystem and soil-health quality. Furthermore, when the chemicals in same soil environment act one another, they could boost up the potential danger of soil ecosystem contaminated by the three pollutants.The joint toxic effects of various chemicals were in relation to their different concentration combinations in soil.