TY - JOUR
T1 - Enantioselective behavior of malathion enantiomers in toxicity to beneficial organisms and their dissipation in vegetables and crops
AU - Sun, Mingjing
AU - Liu, Donghui
AU - Dang, Ziheng
AU - Li, Ranhong
AU - Zhou, Zhiqiang
AU - Wang, Peng
PY - 2012/10/30
Y1 - 2012/10/30
N2 - The dissipation behavior of the two enantiomers of malathion was elucidated in five plant species using enantioselective high performance liquid chromatography (HPLC), and the acute toxicity of the individual enantiomers toward earthworms and honeybees was studied. The calculated LC50 values of the R-, S- and rac-malathion to earthworms were 0.3869, 25.17, and 19.19μg/cm2, respectively, while the calculated LC50 values of R-, S- and rac-malathion to bees were 2.15, 36.67, and 7.11μg/mL, respectively. This indicated that the R-enantiomer was more toxic than S-enantiomer. The results of the degradation of racemate in Chinese cabbage and rape showed that the inactive S-(-)-enantiomer degraded faster than the active R-(+)-enantiomer. Inversely, we found a preferential degradation of the R-(+)-enantiomer in sugar beet. However, the degradation of malathion in paddy rice and wheat were nonenantioselectivity. In all plants, malathion was degraded to levels <10% after 5 days, and the calculated t1/2 values of the enantiomers ranged from 0.83 to 1.43 days in these five plants. In conclusion, our findings of enantioselectivity in the environmental fate and acute toxicity of the malathion enantiomers may have implications for better environmental and ecological risk assessment for chiral pesticides in general.
AB - The dissipation behavior of the two enantiomers of malathion was elucidated in five plant species using enantioselective high performance liquid chromatography (HPLC), and the acute toxicity of the individual enantiomers toward earthworms and honeybees was studied. The calculated LC50 values of the R-, S- and rac-malathion to earthworms were 0.3869, 25.17, and 19.19μg/cm2, respectively, while the calculated LC50 values of R-, S- and rac-malathion to bees were 2.15, 36.67, and 7.11μg/mL, respectively. This indicated that the R-enantiomer was more toxic than S-enantiomer. The results of the degradation of racemate in Chinese cabbage and rape showed that the inactive S-(-)-enantiomer degraded faster than the active R-(+)-enantiomer. Inversely, we found a preferential degradation of the R-(+)-enantiomer in sugar beet. However, the degradation of malathion in paddy rice and wheat were nonenantioselectivity. In all plants, malathion was degraded to levels <10% after 5 days, and the calculated t1/2 values of the enantiomers ranged from 0.83 to 1.43 days in these five plants. In conclusion, our findings of enantioselectivity in the environmental fate and acute toxicity of the malathion enantiomers may have implications for better environmental and ecological risk assessment for chiral pesticides in general.
KW - Acute toxicity
KW - Beneficial organisms
KW - Enantioselective degradation
KW - Malathion enantiomers
UR - http://www.scopus.com/inward/record.url?scp=84866768153&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2012.08.021
DO - 10.1016/j.jhazmat.2012.08.021
M3 - Article
C2 - 22964386
AN - SCOPUS:84866768153
SN - 0304-3894
VL - 237-238
SP - 140
EP - 146
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
ER -