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Comparison of R ‐metalaxyl and rac ‐metalaxyl in acute, chronic, and sublethal effect on aquatic organisms: Daphnia magna, Scenedesmus quadricanda , and Danio rerio
Author(s) -
Yao Kun,
Zhu Lin,
Duan Zhenghua,
Chen Zhongzhi,
Li Yan,
Zhu Xiaoshan
Publication year - 2009
Publication title -
environmental toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.813
H-Index - 77
eISSN - 1522-7278
pISSN - 1520-4081
DOI - 10.1002/tox.20415
Subject(s) - metalaxyl , daphnia magna , toxicity , biology , pesticide , chronic toxicity , tetrahymena pyriformis , acute toxicity , toxicology , scenedesmus obliquus , acceptable daily intake , danio , algae , pharmacology , chemistry , botany , zebrafish , biochemistry , ecology , organic chemistry , gene , tetrahymena
Chiral pesticides are used widely in the world, and at present, older racemic products are being replaced by enantiopure products because of accelerated development of asymmetry synthesis techniques. Pesticides as xenobiotic released into environment impose a great stress on nontarget organisms. Although it is a necessary procedure for pesticides to have a registration based on toxicological data from nontarget organism, until now ecological risk assessment about metalaxyl only depend on racemic products. Hence, we investigated the acute, chronic, and sublethal toxicity of R ‐metalaxy and rac ‐metalaxyl on aquatic organisms such as D. magna ( Daphnia magna ), algae ( Scenedesmus quadricanda ), and adult zebrafish ( Danio rerio ). The results showed a significant difference in toxicity between R ‐metalaxyl and rac ‐metalaxyl. R ‐Metalaxy was about 20‐fold more toxic to algae than rac ‐metalaxyl with IC 50 of 222.89 ± 1.18 mg/L and 19.95 ± 1.12 mg/L, respectively. Similarly, R ‐metalaxyl was about fourfold toxic to D. magna than rac ‐metalaxyl according to the individual 24‐h‐LC 50 values, and sixfold toxic than rac ‐metalaxyl based on 24‐h‐EC 50 values. In the light of 48‐h‐LC 50 and EC 50 , this difference in toxicity was more significant. As for adult zebrafish, there was no pronounced difference in acute toxicity, in addition, at sublethal level a different pattern in inducing Na + ,K + ‐ATPase activity between them was found. In general, R ‐metalaxyl seemed more toxic to aquatic organisms than rac ‐metalaxyl. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009.