Bioaccumulation of PGEs and other traffic-related metals in populations of the small mammal Apodemus sylvaticus

The accumulation of the platinum group elements (PGEs), Pd, Pt, Rh, and other heavy metals (Cd, Cr, Cu, Mn, Ni, Pb, Zn) in the wood mouse Apodemus sylvaticus was investigated in relation to environmental availability, comparing levels in the commonly used target tissues, the liver and kidney, to hair responses. In particular the research aimed to evaluate the suitability of a non-destructive hair-based biomonitoring approach and the responsiveness of PGEs as tracers for the environmental hazard assessment of pollutants linked to traffic in intensively anthropized areas.The four populations considered, inhabiting an urban, a suburban, an agricultural and a reference site, respectively, were shown to be capable of characterizing the differently polluted areas. In particular, multivariate analysis showed a significant correlation between metal levels in tissues and soils. Animals from both the urban and suburban sites, compared to those from the reference site, showed higher levels of those elements (PGEs, Cd, Cr, Ni, Pb and Zn), the availability of which is likely to be related to road traffic. On the contrary, Mn and Cu characterized the animals from the agricultural site. Even though the detected metal concentrations in tissues did not exceed the LOAEL levels, stress indices such as the PGE, Cd and Pb kidney/liver ratios and the kidney/body weight ratios were found to be altered.Significant correlations were established between hair and both internal tissues and soils, for non-essential metals PGE, Cd, Ni and Pb, and also for biologically essential Zn, the level of which was high in urban soils. Hair proved to be a suitable non-invasive tool for monitoring metal exposure responses in small mammals.