title: A fragment constant QSAR model for evaluating the EC50 values of organic chemicals to Daphnia magna.
abstract: The quantitative relationship between the median effective concentration (EC50) of organic chemicals to Daphnia magna and the number of molecular fragments was investigated based on experimental EC50 values for 217 chemicals derived from the literature. A fragment constant model was developed based on a multivariate linear regression between the number of fragments and the logarithmically transformed reciprocal values of EC50. Functional correction factors were introduced into the model. The model was verified using an independent set of randomly selected data. The mean residual of the final model was 0.4 log-units. The robustness of the model was discussed based on the results of three jackknife tests.
authors.affiliation: Laboratory of Earth Surficial Processes of Ministry of Education, Department of Urban and Environmental Sciences, Peking University, Beijing, China. taos@urban.pku.edu.cn
authors.forename: Shu
authors.initials: S
authors.lastname: Tao
authors.forename: Xiaohuan
authors.initials: X
authors.lastname: Xi
authors.forename: Fuliu
authors.initials: F
authors.lastname: Xu
authors.forename: Bengang
authors.initials: B
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Cao
authors.forename: R
authors.initials: R
authors.lastname: Dawson
mesh_terms: D000818:Animals; D003621:Daphnia; D007928:Lethal Dose 50; D008962:Models, Theoretical; D012016:Reference Values; D013329:Structure-Activity Relationship; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical