Seasonal variability of mercury and heavy metals in roe deer (Capreolus capreolus) kidney.

The seasonal variability of Hg, Pb, Cd and Zn was determined in the kidney of 164 roe deer, shot in three areas of Slovenia in 1998. We found a strong seasonal influence on Hg and Pb levels, which were significantly higher in late summer and early autumn. Cd and Zn levels showed a similar seasonal pattern, although not so pronounced; for these elements differences among periods were probably not a consequence of season per se. Seasonal variability in metal levels in roe deer kidney originated in both quantitative and qualitative differences in nutrition of the species. Since the seasonal peaks for the majority of metals appeared in a very narrow summer autumnal period (August-September), it seems that some plant taxons, such as fungi, might represent an important pathway for heavy metal intake into the mammalian organism. The season of sample collection has to be considered whenever using wildlife as an accumulative bioindicator of environmental pollution. Moreover, the influence of the season should be born in mind whenever a hazard due to accumulation of heavy metals along the food chain is assessed.