Cadmium bioaccumulation factors for terrestrial species: Application of the mechanistic bioaccumulation model OMEGA to explain field data

In environmental risk assessment of metals it is often assumed that the biota-to-soil accumulation factor (BSAF) is generic and constant. However, previous studies have shown that cadmium bioaccumulation factors of earthworms and small mammals are inversely related to total soil concentrations. Here, we provide an overview of cadmium accumulation in terrestrial species belonging to different trophic levels, including plants, snails and moles. Internal metal concentrations of these species are less than linearly related to total soil levels, which is in accordance with previously observed trends. The mechanistic bioaccumulation model OMEGA (Optimal Modeling for Ecotoxicological Applications) is used to provide a quantitative explanation of these trends in cadmium accumulation. Our results indicate that the model accurately predicts cadmium accumulation in earthworms, voles and shrews when accounting for geochemical availability of metals and saturable uptake kinetics.