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(226) Normalisation of a new protocol using snails to evaluate the effects of pollutants. de Vaufleury, Annette1, Coeurdassier, Michael1, 1 ABSTRACT- To assess the toxicity of substances, preparations, soils or waste, only 4 standardised tests using soil invertebrates are available. Terrestrial snails satisfy the criteria for good biological indicators representative of animals living in the surface layer of the soil (ingestion, egg laying, development and hibernation), pollution uptake occurring via digestive, cutaneous and respiratory routes. Lastly, their perfectly controlled rearing straightforwardly provides juvenile snails for toxicity tests. After having shown that growth inhibition of Helix aspersa (total mass and shell diameter) was a suitable end point for the evaluation of the effects of pollutants (metallic, organic or contaminated soils), a ring test was carried out in France to standardise two modes of exposure (with Cd as reference substance): by contaminated food or by contaminated substrate. The values of EC50-28 days( Key words: toxicity, snails, growth, normalisation |
g Cd /g food or substrate; respectively /total mass and shell diameter) are:65-150 and 100-160 when the food is contaminated; when the substrate is contaminated 500-900 and 700-1000 (static mode of exposure), 350-650 and 500-800 (semi-static mode of exposure). The results showed that, for Cd, snails are more sensitive to a contamination of their food than of their substrate. This led to the drafting of 2 experimental French standards (NF X 31-255-1 and -2) which should be submitted to the ISO.Cd concentrations measured in snails are promising for further development using snails as test organisms with bio-accumulation as end point.