An evaluation of the levels of organochlorine compounds (OCPs and PCBs) in cultured freshwater and wild sea fish eggs as an exposure biomarker for environmental contamination

In this study, the eggs of 30 wild Black Sea whiting (Merlangius merlangus euxinus, Nordmann, 1840) and 30 farmed freshwater rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) collected from Samsun Province in Turkey were analyzed to determine the level of contamination by nine organochlorine pesticides (OCPs), namely α-hexachlorocyclohexane (α-HCH), β-HCH, γ-HCH (lindane), hexachlorobenzene (HCB), aldrin, 2,4′-dichlorodiphenyltrichloroethane (DDT), 4,4′-DDT, 2,4′-dichlorodiphenyldichloroethylene (DDE), 4,4′-DDE, and 15 polychlorinated biphenyls (PCBs) (PCB-28, -70, -74, -81, -99, -101, -118, -138, -153, -156, -170, -180, -183, -187, and -208), and their potential use as biomarkers to monitor levels of environmental contamination. OCPs and PCBs in the fat of fish eggs were extracted cryogenically and their concentrations were determined with a gas chromatography-electron capture detector (GC-ECD). The whiting eggs showed high OCP and PCB levels compared to the rainbow trout eggs. The median ∑ DDT values for whiting and rainbow trout eggs were 1601.62 ng g⁻¹ fat (range 824.87–5049.81) and 406.49 ng g⁻¹ fat (range 199.88–588.82); median ∑Indicator PCBs were 1264.24 ng g⁻¹ fat (range 520.05–6140.32) and 82.11 ng g⁻¹ fat (range 2.85–215.97); and median ∑ HCHs were 155.66 ng g⁻¹ fat (range 35.45–330.40) and 13.48 ng g⁻¹ fat (range 4.44–66.44), respectively. In the whiting eggs, the ∑Indicator PCB level was above the maximum residue limit (MRL) of 200 ng g⁻¹ fat stated in the European Commission Regulation (EC) and Turkish Food Codex (TFC). In addition, there was a significant difference between the contamination levels of the eggs of the two species. In conclusion, it appears that fish eggs can serve as a valuable biomarker for the level of contamination of persistent organochlorine contaminants in different aquatic environments.