Tissue distribution and maternal transfer of persistent organic pollutants in Kentish Plovers (Charadrius alexandrines) from Cangzhou Wetland, Bohai Bay, China

Highlights: • OCPs, PCBs, PBDEs and PCDD/Fs were comprehensively investigated in the bird tissues. • Significant correlations were found between concentrations in the bird tissues. • No significant differences were found between concentrations in muscle and liver. • Higher muscle/liver rations were found for compounds of log K_ow of 6.5–7.0. • More persistent compounds seemed to be more accumulated in egg. Several persistent organic pollutants, including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs), were comprehensively investigated in the egg, muscle and liver samples of Kentish Plover (Charadrius alexandrines) collected from Cangzhou Wetland in western Bohai Bay, China. DDTs were the most abundant contaminants (35.4–9853 ng g^{− 1} lipid weight, lw), followed by HCHs, PCBs, PBDEs and HCB. PCDD/Fs exhibited the lowest concentrations in all tissues (8.74–4763 pg g^{− 1} lw). PCBs and PCDD/Fs were dominated by penta- and hexa-homologs, and PBDEs mostly consisted of the signature congeners of BDE formulations, such as BDE-209, −47, −153 and −99. Significant correlations were found between the lipid-normalized concentrations in muscle and liver (r: 0.37–0.90, p < 0.05) and no significant differences (p < 0.05), indicating the homogenous distribution of POPs in tissue lipids at steady state. The ratios of concentrations in muscle and liver (M/L) ranged from 0.20 to 1.51, and higher ratios of M/L were found for those compounds with log K_ow in the range of 6.5–7.0, suggesting the preferential accumulation of mid-halogenated compounds in muscle. Significant correlations were generally observed between the concentrations in egg and the maternal tissue (p < 0.05). The concentration ratios of egg to liver (E/L) were in the range of 0.10–1.24 except for p,p'-DDT (12.7), and compounds with log K_ow of 6.5–7.0 exhibited higher E/L ratios, suggesting the selective maternal transfer of mid-halogenated compounds.