title: Effect of major cations and pH on the acute toxicity of cadmium to the earthworm Eisenia fetida: implications for the biotic ligand model approach.
abstract: The purpose of this study was to characterize the individual effect of different cations (Ca(2+), Mg(2+), Na(+), K(+), and H(+)) on the acute toxicity of Cd to the earthworm Eisenia fetida. Higher activities of the considered cations increased the 48-h LC(50) (expressed as Cd(2+) activities) linearly to different extents in simulated soil solution. The conditional constants for the binding of H(+ )(log K = 5.41), Cd(2+ )(log K = 4.0), Ca(2+ )(log K = 3.35), Mg(2+ )(log K = 2.82), Na(+ )(log K = 1.57), and K(+ )(log K = 2.31) to the biotic ligand (BL) of E. fetida were derived from the toxicity data based on the biotic ligand model (BLM). Furthermore, it was calculated that on average 72% of the BL sites needed to be occupied by Cd(2+) to induce 50% lethal effect. Autovalidation of the model with the results of the test sets showed that 48-h LC(50 )could be predicted within a factor of two.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
authors.forename: Lian-Zhen
authors.initials: LZ
authors.lastname: Li
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Zhou
authors.forename: Xiao-San
authors.initials: XS
authors.lastname: Luo
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Quan-Ying
authors.initials: QY
authors.lastname: Wang
mesh_terms: D000818:Animals; D002104:Cadmium / Q000633:toxicity*; D006863:Hydrogen-Ion Concentration; D007928:Lethal Dose 50; D008024:Ligands; D008670:Metals / Q000494:pharmacology*; D008954:Models, Biological; D009835:Oligochaeta / Q000187:drug effects*; D011522:Protons; D023382:Toxicity Tests, Acute
chemical_list: D008024:Ligands; D008670:Metals; D011522:Protons; D002104:Cadmium