Distribution of essential and toxic metals in the terrestrial gastropod Arion ater

A study was made of the metal concentrations in the slug Arion ater at two sites. In whole animals, all metals analysed, except magnesium, were higher in concentration at the Cwmystwyth site where high amounts of lead, zinc and manganese but low concentrations of calcium and phosphate were found in vegetation. Individual tissue analyses showed high concentrations of magnesium, zinc, cadmium and phosphate in digestive gland and high concentrations of calcium in digestive gland and mantle. Lead and copper did not concentrate to any extent in a specific tissue. Manganese was located mainly in mantle, skin and foot. Mucus secreted from Cwmystwyth slugs contained high amounts of zinc and manganese, and granules isolated from the digestive gland, more zinc. Both extracts contained less calcium and magnesium than extracts from campus slugs. The results are discussed in relation to metal concentrations in vegetation and soil together with excretion and uptake mechanisms.