Organochlorine pesticides and polychlorinated biphenyl congeners in wild terrestrial mammals from Croatia: Interspecies comparison of residue levels and compositions

• PCBs and OCPs were determined in adipose tissue of wild bear and wolf from Croatia.
• PCBs were dominant accounting for 72–81% of total analyzed POPs.
• Distribution of PCBs was species dependent.
• The results were discussed in the light of different food preferences of species.
• Contaminant levels were low and normal for large terrestrial carnivores.

In this pilot study, we investigated levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in the adipose tissues of two free-ranging terrestrial carnivores from Croatia sampled in 2010 and 2011: the brown bear (Ursus arctos; N = 32) and the grey wolf (Canis lupus; N = 29). Concentrations of ∑OCPs and ΣPCBs ranged from 0.45 to 4.09 ng g−1 lipid mass (lm) and from 0.93 to 8.52 ng g−1 lm in brown bear, and from 1.18 to 5.67 ng g−1 lm and 2.68 to 48.9 ng g−1 lm in grey wolf adipose tissues, respectively. PCBs were dominant accounting for over 72% of total analyzed persistent organic pollutants (POPs). The sum of six indicator non-dioxin-like PCBs (Σ6IndNDL PCBs) made up 60–93% and 58–85% of the total congener concentrations in brown bears and wolves, respectively. Although the levels of the measured parameters were significantly higher in grey wolves than in bears, the contaminant profiles of the two species were similar, with γ-HCH, HCB, β-HCH and DDE as major OCP contaminants, and PCB-153 > PCB-180 ≈ PCB-170 > PCB-138 as the dominant congeners. The sum of hexachlorocyclohexanes (ΣHCHs) and 8 toxicologically relevant dioxin-like PCBs (Σ8ToxDL PCBs) was higher in the males than in the females of the brown bear. Concentrations of ΣDDTs, HCB, ΣOCP, ΣPCBs, Σ6IndNDL PCBs, and toxicologically relevant non-dioxin-like PCBs (ΣToxNDL PCBs) were significantly positively correlated with lipid content in the grey wolf. Concentrations of OCPs and PCBs in brown bears and wolves from Croatia were low and normal for large terrestrial mammals.