Résumé :
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Earthworms (Oligochaeta) represent an important food source for many vertebrates and as a result, predators may encounter toxic effects via the food chain (secondary poisoning) from consumption of contaminated worms. Therefore, including an assessment of secondary poisoning in risk assessment procedures is advisable. In this study, a mechanistic model is presented for estimating bioconcentration of organic chemicals in earthworms. It is assumed that bioconcentration can be described by a thermodynamic partitioning between soil solids, soil water, and the resident organism's tissues. For most chemicals, the lipid phase is the dominant site for sorption in the earthworm, but for more hydrophilic compounds, the water phase may also play a role. Model predictions are compared to literature data that were derived from experiments with earthworms in water, laboratory experiments with various soils, and from field experiments. Without calibration, the model was able to accurately predict bioconcentration factors (BCFs) from experiments in water, indicating the applicability of this theoretical approach.
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