PARENT SESSION

2A - Mixture toxicity
Poster Hall
8:30 AM - Monday, 28 April 2003
Chair: Hermens, J.¹, ¹
Co-chair: Toy, R.², Backhaus, T.³, ^{2 3}

(MOP/83) Effects of sewage sludge on survival, growth and bioaccumulation of trace elements in terrestrial snails.

de Vaufleury, Annette¹, Coeurdassier , Michael¹, Crini, Nadia¹, Lovy, Christiane¹, Badot, Pierre-Marie¹, ¹ University of Franche-Comté, Besançon, France, France

ABSTRACT- Among soil invertebrates, gastropod may be affected by the used of sewage sludge for agricultural amendment. The effects of such a complex matrix on survival and growth (measured by the total fresh mass, FM and the shell diameter, SD) of juvenile Helix aspersa, were assessed with standardised methods (NF X 31-255-1 and -2). As in the field, snails are exposed to pollutants by the food and the soil, EC50-28 days were measured separately for each source of contamination. Dose-dependent effects were assessed by dilution of the municipal sewage sludge either by artificial substrate (ISO substrate) or by a natural agricultural soil (NS). After 28 days of exposure, growth was less affected by food exposure to the sludge (EC50-FM and EC50-SD: 55 and 60% respectively) than by substrate contamination. For this modality of exposure, results were similar after dilution of the sludge with the NS (EC50-FM and EC50-SD: 10.8 and 19.3%) or with ISO substrate (EC50-FM and EC50-SD: 10.2 and 14.1%). This difference was confirmed by the results for survival . Cu, Zn, Pb, Ni and Cr in the sludge were under the regulation-limit values and lower than the EC50-28 days for growth inhibition of Helix aspersa for food contamination (1180; 5800; > 30,000 and 300 ppm respectively for Cu, Zn, Pb and Cr). This suggests a synergy between these elements, and may be with PAHs and PCBs that were also detected in the sludge. In the snails, Cu and Zn were strongly accumulated. Pb, Ni and Cr reflected the contamination of food or substrate but were effectively regulated. Present data enhanced the interest of these methods of exposure which are currently approved as active work item (ISO 15952) at the ISO level (TC 190 soil quality) for the evaluation of effects as well as for bioaccumulation studies.

Key words: snail, waste, growth, bioaccumulation