IFREMER (French Research Institute for Exploitation of the Sea), Laboratory of Biogeochemistry of Organic Contaminants, Rue de l'Ile d'Yeu, BP 21105, 44311 Nantes Cedex 3, France.
IFREMER (French Research Institute for Exploitation of the Sea), Laboratory of Biogeochemistry of Organic Contaminants, Rue de l'Ile d'Yeu, BP 21105, 44311 Nantes Cedex 3, France.
Sci Total Environ. 2021 Jan 10;751:141807. doi: 10.1016/j.scitotenv.2020.141807. Epub 2020 Aug 20.
The contamination of tiger sharks (Galeocerdo cuvier) and bull sharks (Carcharhinus leucas) by legacy persistent organic pollutants (POPs) and emerging organic contaminants was investigated in specimens from Reunion Island (Southwest Indian Ocean) in 2018 and 2019. Contamination levels were determined in the muscle of adult individuals of both sexes in relation to biological and trophic parameters. Maternal transfer was additionally investigated in one set of embryos in each species. Polychlorinated biphenyl (PCB), organochlorinated pesticide (OCP) and perfluoroalkylated substance (PFAS) concentrations were 2597 ± 2969, 785 ± 966 and 267 ± 194 pg g-1 ww, respectively, in bull sharks, and 339 ± 270, 1025 ± 946 and 144 ± 53 pg g-1 ww in tiger sharks. The results highlighted higher PCB contamination, and by the heavier congeners, in adult bull sharks versus tiger sharks. The significant differences found in PCB profiles and concentrations suggest that the two species are exposed to different contamination sources. As bull sharks rely on a more coastal habitat for feeding, their higher contamination by PCBs suggests the occurrence of local PCB sources. DDT concentrations were similar in both species, suggesting a more homogeneous contamination on the scale of the Southwest Indian Ocean. Female bull sharks showed lower OCP and PCB concentrations than males, while this trend was not observed in tiger sharks. The ratio of chlorinated contaminants in muscle between the mother and her embryos was related to molecule hydrophobicity in bull shark but not in tiger shark, suggesting that shark mode of gestation, known to be different in the two species, is a key driver of organic contaminant maternal transfer. Finally, the results show that organic contaminant levels in the studied species were lower than those of other shark species in the Southern Hemisphere, related to the limited urbanization and industrialization of Reunion Island.
在 2018 年和 2019 年，对来自印度洋西南部留尼汪岛的虎鲨（Galeocerdo cuvier）和牛鲨（Carcharhinus leucas）的样本进行了研究，以调查其持久性有机污染物（POPs）和新兴有机污染物的污染情况。在两性成年个体的肌肉中，根据生物和营养参数确定了污染水平。另外，还在每个物种的一组胚胎中研究了母体转移。在牛鲨中，多氯联苯（PCB）、有机氯农药（OCP）和全氟烷基物质（PFAS）的浓度分别为 2597±2969、785±966 和 267±194 pg g-1 ww，而在虎鲨中则分别为 339±270、1025±946 和 144±53 pg g-1 ww。结果表明，成年牛鲨体内的 PCB 污染程度更高，且更为重的同系物浓度更高。在 PCB 谱和浓度方面发现的显著差异表明，这两个物种受到不同的污染源的影响。由于牛鲨在觅食时更多地依赖沿海栖息地，因此它们受到更高的 PCB 污染，这表明存在当地的 PCB 源。两种物种的滴滴涕浓度相似，这表明在西南印度洋范围内的污染较为均匀。与雄性相比，雌性牛鲨的 OCP 和 PCB 浓度较低，而在虎鲨中则没有观察到这种趋势。牛鲨肌肉中母体和胚胎之间氯化污染物的比例与分子疏水性有关，但在虎鲨中则没有，这表明鲨鱼的妊娠模式，已知在两个物种中不同，是有机污染物母体转移的关键驱动因素。最后，结果表明，在所研究的物种中，有机污染物的水平低于南半球其他鲨鱼物种，这与留尼汪岛有限的城市化和工业化有关。
