Soil parameters are key factors to predict metal bioavailability to snails based on chemical extractant data

• DOI: 10.1016/j.scitotenv.2012.05.048
• Publication Date: 2012-06-27T00:48:03Z
• Authors: B. Pauget; F. Gimbert; R. Scheifler; M. Coeurdassier; A. de Vaufleury
• Keywords: LUMBRICUS-RUBELLUS; MESH: Hydrogen-Ion Concentration; 550; PH; Snails; MESH: Zinc; 01 natural sciences; MESH: Chemistry Techniques; Soil; Soil Pollutants; MESH: Animals; MESH: Snails; Assimilation flux; Risk assessment; MESH: Biological Availability; CONTAMINATED SOILS; MESH: Chemistry Techniques, Analytical; Hydrogen-Ion Concentration; 6. Clean water; ORGANIC-MATTER; Zinc; Metals; Aluminum Silicates; [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology; MESH: Environmental Monitoring; MESH: Lead; Cadmium; Environmental Monitoring; MESH: Edetic Acid; MESH: Environmental Exposure; MESH: Cadmium; Biological Availability; HELIX-ASPERSA; Chemistry Techniques, Analytical; CADMIUM; MESH: Soil; HEAVY-METALS; Animals; Chemical method; Edetic Acid; 0105 earth and related environmental sciences; EARTHWORMS; MESH: Soil Pollutants; MESH: Metals; Environmental Exposure; Analytical; Transfer; Kinetics; DERMAL UPTAKE; Lead; 13. Climate action; MESH: Aluminum Silicates; Clay; DUTCH FIELD SOILS

Although soil characteristics modulate metal mobility and bioavailability to organisms, they are often ignored in the risk assessment of metal transfer. This paper aims to determine the ability of chemical methods to assess and predict cadmium (Cd), lead (Pb) and zinc (Zn) environmental bioavailability to the land snail Cantareus aspersus. Snails were exposed in the laboratory for 28 days to 17 soils from around a former smelter. The soils were selected for their range of pH, organic matter, clay content, and Cd, Pb and Zn concentrations. The influence of soil properties on environmental availability (estimated using HF-HClO(4), EDTA, CaCl(2), NH(4)NO(3), NaNO(3), free ion activity and total dissolved metal concentration in soil solution) and on environmental bioavailability (modelled using accumulation kinetics) was identified. Among the seven chemical methods, only the EDTA and the total soil concentration can be used to assess Cd and Pb environmental bioavailability to snails (r²(adj)=0.67 and 0.77, respectively). For Zn, none of the chemical methods were suitable. Taking into account the influence of the soil characteristics (pH and CEC) allows a better prediction of Cd and Pb environmental bioavailability (r²(adj)=0.82 and 0.83, respectively). Even though alone none of the chemical methods tested could assess Zn environmental bioavailability to snails, the addition of pH, iron and aluminium oxides allowed the variation of assimilation fluxes to be predicted. A conceptual and practical method to use soil characteristics for risk assessment is proposed based on these results. We conclude that as yet there is no universal chemical method to predict metal environmental bioavailability to snails, and that the soil factors having the greatest impact depend on the metal considered.