Environmental behavior of the chiral insecticide fipronil: Enantioselective toxicity, distribution and transformation in aquatic ecosystem.
The enantioselective environmental behaviors of the chiral insecticide fipronil and its metabolites in lab-scale aquatic ecosystems were studied and the toxicity of fipronil enantiomers and the metabolites to non-target organisms Lemna minor (L. minor) and Anodonta woodiana (A. woodiana) was also investigated in this work. Water-sediment, water-L. minor, water-A. woodiana, and water-sediment-L. minor-A. woodiana ecosystems were set up and exposed to fipronil through a 90-day period. The results showed fipronil could be degraded significantly faster (half-life of 4.6 days) in the complex water-sediment-L. minor-A. woodiana ecosystem. A. woodiana played a crucial role in the dissipation of fipronil, and the microorganisms in the sediment also made great contribution to the degradation of fipronil in aquatic ecosystems. All the three metabolites fipronil desulfinyl, fipronil sulfide and fipronil sulfone were detected in the ecosystems and were more persistent than fipronil. Enantioselective degradation of fipronil was observed with S-fipronil being preferentially degraded in sediment and L. minor, while R-fipronil was metabolized preferentially in A. woodiana. EC50for L. minor was obtained using 7-day exposure, and for A. woodiana was obtained using 72-h exposure. S-fipronil was more toxic to A. woodiana, while R-fipronil showed higher toxicity to L. minor. Moreover, the three metabolites were found more toxic than fipronil indicating significant environment risks due to their persistence. The present study might have important implications for the risk assessment of fipronil and its metabolites in real aquatic environment.
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, Beijing 100193, PR China.
Han
H
Qu
Beijing Key Laboratory of Emerging Organic Contaminants Control, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Collaborative Innovation Center for Regional Environmental Quality, School of Environment, Tsinghua University, Beijing 100084, PR China.
Rui-Xue
RX
Ma
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, Beijing 100193, PR China.
Dong-Hui
DH
Liu
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, Beijing 100193, PR China.
Jing
J
Gao
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, Beijing 100193, PR China.
Fang
F
Wang
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, Beijing 100193, PR China.
Zhi-Qiang
ZQ
Zhou
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Department of Applied Chemistry, China Agricultural University, Beijing 100193, PR China. Electronic address: wangpeng@cau.edu.cn.
Peng
P
Wang
D017753:Ecosystem; D006207:Half-Life; D007306:Insecticides
D007306:Insecticides
Aquatic ecosystem; Enantioselectivity; Fipronil; Metabolites; Toxicity; Transformation