The snail as a target organism for the evaluation of industrial waste dump contamination and the efficiency of its remediation.

The diagnosis of contamination and the efficiency of remediation of an industrial waste dump (IWD) were done before and after remediation. For this study, two species of snails were used for passive and active biomonitoring: a nonnative species, Helix pomatia and young garden snails (Helix aspersa aspersa) of standardized rearing (age, 2 months). Bioaccumulation analysis of pollutants (cadmium, nickel, iron, lead, chromium, manganese, copper, and zinc) in viscera of the snails gave data on the evolution of the biotop biodisponibility over time. Those data allowed the conclusion that the snails were useful for passive and active biomonitoring. Comparison of two contamination grids corroborated previous conclusions. Furthermore, the results obtained indicated the efficiency of the remediation technique used for the IWD.

Growing snails used as sentinels to evaluate terrestrial environment contamination by trace elements.

Young garden snails (Helix aspersa) reared in standard conditions (aged two months, mean weight 4.6 +/- 0.5 g) set as sentinels in cages laid on the soil for four weeks, give data for biomonitoring the environmental impact of chemicals on soil ecosystems in the field. The survival and the growth of the snails are influenced by the nature of the biotope and the level of the pollutants. Assay of cadmium, copper, lead and zinc bioaccumulated in the tissues of the sentinel snails provides information on the bioavailability of metals in the environment. The encagement model, little used for terrestrial species, can be useful in monitoring (specific and global endpoints) metal pollution of the environment in reference to the trophic level of the primary consumers. Active biomonitoring is positively compared with the passive biomonitoring.

Comparison of the bioaccumulation capacities of copper and zinc in two snail subspecies (Helix).

Bioaccumulation analyses of copper and zinc were carried out in two snail subspecies (Helix aspersa aspersa and Helix aspersa maxima) after 3 months of controlled farming (out of ground) with foods of different formulations. The results reveal some clear interspecific differences in affinity toward copper and zinc. For the two metals considered, H. aspersa aspersa has a bioaccumulation capacity much greater than that of H. aspersa maxima, mainly in the foot for copper and in the viscera for zinc. After 3 months, the concentrations of copper in feet and viscera are much higher than those presented in the literature on field animals. The farming and the analysis methodologies permitted obtaining snails under standard condition and open the way to the development of rational protocols for ecotoxicological studies in a laboratory as well as in the field.