THE INFLUENCE OF SIZE ON THE ACCUMULATED AMOUNTS OF METALS (Cu, Pb, Cd, Zn AND Ca) IN SIX SPECIES OF SLUG SAMPLED FROM A CONTAMINATED WOODLAND SITE

Heavy metal concentrations in 6 terrestrial slug species (Deroceras reticulatum, D. caruanae, Arionater, A. hortensis, A. subfuscus and Milax budapestensis) inhabiting a disused Pb/Zn mine site were measured by atomic absorption spectrophotometry. Relationships between dry weight: metal content and dry weight: metal concentration, respectively, were investigated by regression analysis before and after log transformation. Interspecies, as well as inter-metal differences in metal accumulation were more effectively demonstrated by comparing metal content: dry body weight relationships, as opposed to metal concentration: dry body weight relationships. Regression analysis revealed differences in metal accumulation between the non-essential trace metals Pb/Cd and the metabolically essential trace metals Zn/Cu. Species differences in metal accumulation were more pronounced when their coefficients of functional regression were compared, the greatest differences being observed for species belonging to different genera. However, the presence of a high level of intrinsic variability in metal levels reduces the effectiveness and significance of the metal content: dry body weight expressions, and also detracts from the immediate prospect of using terrestrial slugs as biomonitors of environmental metal pollution.