Age Differences in Bioaccumulation of Heavy Metals in Populations of the Black-Striped Field Mouse, Apodemusagrarius(Rodentia, Mammalia)

Bioaccumulation of heavy metals in the skulls of black-striped field mice (Apodemusagrarius) was compared for two localities in Serbia differing in the level of pollution. Eight heavy metals: Fe, Mn, Co, Cd, Zn, Ni, Pb and Cu, were quantitatively analyzed by atomic absorption spectrophotometry. Four of them (Mn, Cd, Fe and Ni) showed significantly higher concentrations at the polluted location than in the relatively unpolluted one. Concentrations of heavy metals in three age categories exhibited opposite patterns depending on pollution levels. At the unpolluted locality heavy metal concentrations were the highest in the youngest group and lower in older animals. In contrast, bone metal concentrations increased with age class at the more polluted site. At the same time, we found that young animals from the polluted location had a statistically significant lower relative body mass (RBM) than those from the unpolluted area(t = 7.155, p < 0.001), which may have been caused by heavy metals or other factors associated with pollution. In general, we found that age is a critical factor for estimating the level of heavy metal pollution, so proper investigations should account for the age structure of the samples.