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Toxicity of simple mixtures to the nematode Caenorhabditis elegans in relation to soil sorption
Author(s) -
Jonker Martijs J.,
Sweijen Roland A.J.C.,
Kammenga Jan E.
Publication year - 2004
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 - 10.1897/03-29
Subject(s) - sorption , chemistry , environmental chemistry , cadmium , toxicity , copper , adsorption , soil water , freundlich equation , metal , ecology , biology , organic chemistry
Single and combined toxicity of copper‐zinc, copper—cadmium, cadmium—lead, copper—carbendazim, and copper‐carbendazimiprodione to the nematode Caenorhabditis elegans in soil was studied. The one‐week population increase was estimated as the toxicity endpoint. The aim was to study the relationship between mixture interactions in the soil and the combined toxic effect. Soil sorption was quantified using the Freundlich adsorption constant. Joint toxicity patterns were quantified by comparing mixture effects to the effect of individual constituents and were related to total metal concentrations in the soil, water‐soluble concentrations, and 0.01 M CaCl 2 ‐extractable concentrations. The metal with the highest adsorption constant influenced the sorption of metal with the lowest adsorption constant when both were combined, indicating interaction. Consequently, both the composition of the mixture as well as the relative toxicity of individual mixture constituents differed between total, water‐soluble, and CaCl 2 ‐extractable concentrations, which was taken into account in the data quantification procedure that was applied. Both the additive and the independent model were generally inadequate to describe the effects of metal mixtures. Compared to the additive model, synergism was observed at dose levels higher than the median effect isobole. A general relationship between mixture interactions in the soil and the combined toxicity was not found.