The ground beetle Parallelomorphus laevigatus is a potential indicator of trace metal contamination on the eastern coast of Sicily

Abstract

Carabids are generally considered to be non-specialized predators, and they have been considered useful ecological indicators. They can play a key role in clarifying the route of contaminants in food webs because they are predators of small invertebrates and, in turn, part of the diet of several vertebrates. The Mediterranean species Parallelomorphus laevigatus, which so far has not been studied from an ecotoxicological point of view, is an excellent ecological indicator in sandy coastal environments.We investigated the accumulation of trace elements in Ionian populations of P. laevigatus and evaluated the transfer of metal through the food chain of the coastal ecosystem. We analyzed 15 metals, including 11 essential metals (Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Sn, V and Zn) and four toxic metals (As, Cd, Hg and Pb). Significant differences were found in metal concentration in animal tissues among sites.Our results support the existence of defense mechanisms for the studied species.High values of As, Cd, Cr, Pb, Ni, and Hg detected in the beetles from the control site can be explained by both the emission sources from the nearby industrial plants and the intense agricultural activity.The present paper shows increasing Hg concentrations in the simplified trophic web of sandy beaches and confirms the capability of this pollutant to biomagnify. Moreover, the high value of biomagnification factor (BMF) points to the severe pollution level in this protected area.