Biomarkers Responses of Land Snails Helix aspersa Exposed to Chronic Metal Pollution under Field and Laboratory Conditions

The effects of exposure to metals under field and laboratory conditions were investigated in the terrestrial land snail Helix aspersa. In this study, terrestrial snails, collected from an uncontaminated site in Guelma city (North east of Algeria) and transplanted at the industrial zone of El hadjar contaminated by several heavy metals. On the other hand groups of Helix aspersa were exposed to increasing concentrations of industrial metal dust (100, 300 and 500μg/g of diet) for a total duration of 12 weeks. A battery of non-enzymatic biomarkers malondialdehyde (MDA), glutathione (GSH) and enzymatic biomarkers catalase (CAT), glutathione S-transferase (GST) were applied for the estimation of biochemical effects induced by the chronic exposure of snails to mixture of metal dust. Several responses have been revealed in digestive gland, serum and HLS. The results showed that CAT activity and MDA content were significantly higher in snails from the polluted site of El Hadjar and specimens exposed to high concentration of metal dust. In contrast GST activity and GSH level showed significant decrease in both transplanted and metal dust exposed snails. Therefore, our results showed the importance of H. aspersa as a sentinel organism for biomonitoring.