Premium
Rhizotoxicity of cadmium and copper in soil extracts
Author(s) -
Voigt Astrid,
Hendershot William H.,
Sunahara Geoffrey I.
Publication year - 2006
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/04-619r.1
Subject(s) - cadmium , metal , dissolved organic carbon , environmental chemistry , genetic algorithm , copper , chemistry , biotic ligand model , metal ions in aqueous solution , soil water , metal toxicity , inorganic chemistry , heavy metals , soil science , ecology , environmental science , biology , organic chemistry
Dissolved organic matter (DOM) influences metal speciation in soil solutions and, hence, metal toxicity. Root‐elongation experiments were conducted to examine the effect of soil solution components, such as Ca, H, and DOM, on metal rhizotoxicity. A biotic ligand model (BLM) was tested for its ability to predict the rhizotoxicity of Cd and Cu in soil extracts. It was hypothesized that the concentration of Cd and Cu bound to functional groups at the root surface estimated using a BLM would be a better predictor of rhizotoxicity than the free‐metal ion activity in solution. Both metals became less toxic at higher DOM, Ca, and H concentrations. Solution speciation and the effect on root growth explained most of the variability observed in the DOM experiments, but not in the cation experiments. It was concluded that Ca and H inhibited the rhizotoxicity of both metals tested. Rhizotoxicity data correlated better with estimates of metal‐root complexes that have been estimated with a BLM than with free‐metal ion activity or with total metal concentrations. The BLM seems to be a promising approach for predicting metal availability in soils and for assessing the associated risk.