【摘要】 手性农药在环境中表现出不同的生态毒理效应.研究选择盘星藻和斜生栅藻两种淡水藻,探讨了甲霜灵对两种藻的毒性效应,以及甲霜灵在两种藻液体系中的降解及对映异构体选择性.结果表明,在甲霜灵对两种藻的生长抑制实验中,随着甲霜灵浓度的升高,斜生栅藻藻细胞密度呈增长趋势,盘星藻藻细胞密度呈下降趋势,两种藻的96 h生长抑制浓度IC50分别为1. 64 mg/L和44. 56 mg/L.在避光条件下,斜生栅藻和盘星藻对甲霜灵的平均去除率分别为45. 1%和42. 1%,对映异构体的降解无立体选择性;在光照条件下,斜生栅藻和盘星藻对甲霜灵的平均去除率分别为86. 9%和65. 8%,对映异构体存在选择性降解,且R-体甲霜灵优先于S-体甲霜灵被降解.更多还原

【Abstract】 Chiral pesticides exhibit different ecotoxicological effects in the environment. The toxic effects of metalaxyl on,and its selective degradation and enantioselectivity in both Pediastrum and Scenedesmusobliquus were investigated. The results showed that the selectivity of metalaxyl for the inhibition of the two algae is very high.With the increase of the concentration of metalaxyl,the algae cell density of Scenedesmus obliquus increases,whereas that of Pediastrum decreases,with that the 96 h growth inhibition concentration(IC50) of the two algae is 1. 64 mg/L and 44. 56 mg/L,respectively. Under the condition of complete darkness,the average removal rate of metalaxyl in the two algae is 45. 1% and 42. 1%,respectively. Meanwhile,the stereoselectivity for the enantiomeric degradation cannot be detected. Under the lighting conditions,the average removal rate of metalaxyl in the two algae is 86. 9% and 65. 8%,respectively. The selective degraded experiments show that R-metalaxyl is easier to be degraded than S-metalaxyl.更多还原