The emission of anthropogenic chemicals has caused worldwide pollution of our ecosystems. Exposure studies of these chemicals on wildlife have a long tradition, focussing mainly on chemical analyses of tissue residues. Although the effects of these pollutants on the individual and the population are of increasing concern, impact studies on terrestrial wildlife are scarce. Furthermore, there is a need for non-destructive methods as to assess the global impact on mammals. The overall goal of this field study is to investigate the relationships between the exposure of the hedgehog to persistent pollutants (heavy metals, PCBs and organochlorine pesticides) and the effects on a biochemical and population level, using non-destructive methods.A field study of selected hedgehog populations inhabiting park areas along a heavy metal pollution gradient in Antwerp (Belgium) is carried out. Hedgehogs are individually tagged. Furthermore condition indices and population parameters are collected. Hair samples are taken as to assess the contamination of individual hedgehogs, while biochemical effects are measured on blood samples. Some of the effects being measured are hormones, haematological parameters, genetic damage, …Finally, relations between the exposure of the hedgehog to pollutants, the biochemical effects and population-ecological parameters will be investigated. These data will provide us more insight in the impact of persistent pollutants on natural hedgehog populations and more specifically if local populations are at risk.