Identifying semi-volatile contaminants in fish from Niyang River, Tibetan Plateau

This study investigated the contamination levels and profiles of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides (OCPs) including dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) in fish from the Niyang River, Tibetan Plateau. The total concentrations of ∑PCB, ∑PBDE and ∑OCP were in the range of 0.246–1.056 ng/g (mean 0.540 ± 0.289 ng/g), 0.280–2.220 ng/g (mean 0.914 ± 0.643 ng/g) and 7.24–13.80 ng/g (mean 10.70 ± 2.31 ng/g), respectively. The total mercury concentration (HgT) in fish ranged from 85 to 217 ng/g dw with an average of 129 ng/g dw, and the concentrations of methyl mercury (MeHg) ranged from 61 to 160 ng/g dw with an average of 102 ng/g dw. The proportion of MeHg contributed to 66–91 % (average 80 %) of HgT for all samples, indicating that organic mercury was the predominant form of mercury in fish muscle. The results revealed that the fish from the Niyang River were contaminated with various persistent toxic pollutants and the potential influencing factors on the bioaccumulation concentration in fish were analyzed using Pearson’s correlation analysis.