title: Quantitative structure-toxicity relationship study of lethal concentration to tadpole (Bufo vulgaris formosus) for organophosphorous pesticides.
abstract: In the present study more than 1,000 structural parameters of 41 organophosphorus pesticides (OPs) were calculated using the software ChemOffice 8.03 and Dragon 2.1. Then, with multivariate linear regression and best subset regression analyses, different equations were derived to calculate the lethal toxicity, LC(50), for these 41 organophosphorous pesticides found in tadpoles (Bufo vulgaris formosus). An equation was developed for all selected OPs, especially those with relatively low toxicity levels (LC(50)>4.5mM) that accounted for 89.09% of the variability in the toxic effect. The equation indicated that the main contributions to OPs toxicity with tadpoles were the electrostatic contribution qH(+) (maximum net positive H atomic charge), spatial autocorrelation (MATS7 m) and hydrophobicity (lgK(ow)), with the two former being the most important parameters. For OPs with high toxicity, however, different structural parameters were introduced. The following equation was developed with LC(50)<4.5mM. These equations implied that with different levels of toxicity there could have different mechanisms in the tadpole. Furthermore, the results showed that molecular structural parameters had a particular value in modeling chemical reactivity within a homologous series of compounds.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. yandongyun666@hotmail.com
authors.forename: Dongyun
authors.initials: D
authors.lastname: Yan
authors.forename: Xin
authors.initials: X
authors.lastname: Jiang
authors.forename: Shaohui
authors.initials: S
authors.lastname: Xu
authors.forename: Ligang
authors.initials: L
authors.lastname: Wang
authors.forename: Yongrong
authors.initials: Y
authors.lastname: Bian
authors.forename: Guifen
authors.initials: G
authors.lastname: Yu
mesh_terms: D000818:Animals; D002025:Bufonidae; D007814:Larva / Q000187:drug effects; D007928:Lethal Dose 50; D008954:Models, Biological; D009943:Organophosphorus Compounds / Q000737:chemistry / Q000633:toxicity*; D010575:Pesticides / Q000737:chemistry / Q000633:toxicity*; D021281:Quantitative Structure-Activity Relationship
chemical_list: D009943:Organophosphorus Compounds; D010575:Pesticides