Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai Key Laboratory of Marine Bioresources and Environment, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
Department of Biology, University of Texas at Tyler, Tyler, TX, 75799, USA.
Environ Pollut. 2020 Dec;267:115511. doi: 10.1016/j.envpol.2020.115511. Epub 2020 Aug 27.
There is little information about the residue levels and congener composition of organic contaminants (OCs) in cetaceans. In the present study, we investigated the polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in the blubber, blood, brain and testes of Indo-Pacific humpback dolphins (Sousa chinensis) stranded in the Pearl River Estuary (PRE), China. The lowest blubber/tissue partition coefficients were found for sum hexachlorocyclohexanes (ΣHCHs) and ΣPAHs, while the highest were in ΣPCBs and sum dichlorodiphenyltrichloroethanes (ΣDDTs), likely attributing to the octanol-water partition features. The low levels of OCs in brain and testes theoretically resulted from the blood-brain barrier, blood-testes barrier, contaminant molecule dimensions and unique lipid compositions in the brain and testes. Compared with other contaminants, the higher mean brain/blood and testes/blood partition coefficients found for mirex, heptachlor, dieldrin and endrin would increase the risks associated with exposure-related toxicity and the bioavailability of contaminants within these tissues. Observations also suggest that as lipid mobilizes from blubber, contaminants may redistribute, leading to elevated tissue (such as brain) concentrations. Therefore, dolphins with less blubber may be more susceptible to health risks. The Indo-Pacific humpback dolphins living in PRE are at great risk due to variety of OCs in indirect contact with non-target organisms, affecting the health of animals (toxic effects and accumulation). Our findings contribute to the knowledge of the potential effects of OCs exposure on developmental neurotoxicity and reproductive damage in marine mammals.
有关鲸目动物（cetaceans）体内有机污染物（OCs）的残留水平和同系物组成的信息很少。在本研究中，我们调查了在中国珠江口搁浅的印太驼背豚（Sousa chinensis）的鲸脂、血液、大脑和睾丸中的多氯联苯（PCBs）、多环芳烃（PAHs）和有机氯农药（OCPs）。ΣHCHs 和 ΣPAHs 的鲸脂/组织分配系数最低，而 ΣPCBs 和ΣDDTs 的分配系数最高，这可能归因于辛醇-水分配特征。大脑和睾丸中 OCs 的低水平理论上是由于血脑屏障、血睾屏障、污染物分子尺寸以及大脑和睾丸中独特的脂质组成。与其他污染物相比，米瑞克斯、七氯、狄氏剂和异狄氏剂在脑中的平均脑/血和睾丸/血分配系数较高，这将增加与暴露相关的毒性和这些组织中污染物的生物利用度相关的风险。观察结果还表明，随着鲸脂中脂质的动员，污染物可能重新分布，导致组织（如大脑）浓度升高。因此，鲸脂较少的海豚可能更容易受到健康风险的影响。生活在 PRE 的印太驼背豚由于与非目标生物间接接触的各种 OCs 而面临巨大风险，这会影响动物的健康（毒性作用和积累）。我们的研究结果有助于了解 OCs 暴露对海洋哺乳动物发育神经毒性和生殖损害的潜在影响。
