Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées, Université de Toulouse, CNRS, IRD, 14 Avenue E. Belin, F-31400 Toulouse, France; Universidad Andina Simón Bolívar, Área de Salud, P.O. Box 17-12-569, Quito, Ecuador.
Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées, Université de Toulouse, CNRS, IRD, 14 Avenue E. Belin, F-31400 Toulouse, France.
Ecotoxicol Environ Saf. 2021 Jun 1;215:112122. doi: 10.1016/j.ecoenv.2021.112122. Epub 2021 Mar 13.
The human ingestion of mercury (Hg) from sea food is of big concern worldwide due to adverse health effects, and more specifically if shark consumption constitutes a regular part of the human diet. In this study, the total mercury (THg) concentration in muscle tissue were determined in six sympatric shark species found in a fishing vessel seized in the Galapagos Marine Reserve in 2017. The THg concentrations in shark muscle samples (n = 73) varied from 0.73 mg kg in bigeye thresher sharks (Alopias superciliosus) to 8.29 mg kg in silky sharks (Carcharhinus falciformis). A typical pattern of Hg bioaccumulation was observed for all shark species, with significant correlation between THg concentration and shark size for bigeye thresher sharks, pelagic thresher sharks (Alopias pelagicus) and silky sharks. Regarding human health concerns, the THg mean concentration exceeded the maximum weekly intake fish serving in all the studied species. Mass-Dependent Fractionation (MDF, δHg values) and Mass-Independent Fractionation (MIF, ΔHg values) of Hg in whitetip sharks (Carcharhinus longimanus) and silky sharks, ranged from 0.70‰ to 1.08‰, and from 1.97‰ to 2.89‰, respectively. These high values suggest that both species are feeding in the epipelagic zone (i.e. upper 200 m of the water column). While, blue sharks (Prionace glauca), scalloped hammerhead sharks (Shyrna lewini) and thresher sharks were characterized by lower ΔHg and δHg values, indicating that these species may focus their foraging behavior on prey of mesopelagic zone (i.e. between 200 and 1000 m depth). In conclusion, the determination of THg concentration provides straight-forward evidence of the human health risks associated with shark consumption, while mercury isotopic compositions constitute a powerful tool to trace the foraging strategies of these marine predators. CAPSULE: A double approach combining Hg concentrations with stable isotopes ratios allowed to assess ontogeny in common shark species in the area of the Galapagos Marine Reserve and the human health risks concern associated to their consumption.
人类通过食用海鲜摄入汞（Hg），这在全球范围内引起了人们对健康影响的极大关注，尤其是如果鲨鱼消费成为人类饮食的常规部分。在这项研究中，测定了 2017 年在加拉巴戈斯海洋保护区扣押的一艘渔船中发现的六种共生鲨鱼物种的肌肉组织中的总汞（THg）浓度。鲨鱼肌肉样本中的 THg 浓度（n=73）从大眼长尾鲨（Alopias superciliosus）的 0.73mg/kg 到灰真鲨（Carcharhinus falciformis）的 8.29mg/kg 不等。所有鲨鱼物种都表现出典型的汞生物积累模式，大眼长尾鲨、远洋长尾鲨（Alopias pelagicus）和灰真鲨的 THg 浓度与鲨鱼体型之间存在显著相关性。关于人类健康问题的担忧，在所研究的所有物种中，THg 平均浓度均超过每周最大鱼类摄入量。白鳍鲨（Carcharhinus longimanus）和灰真鲨的汞的质量依赖分馏（MDF，δHg 值）和质量独立分馏（MIF，ΔHg 值）范围分别为 0.70‰至 1.08‰和 1.97‰至 2.89‰。这些高值表明，这两个物种都在表水层（即水柱上层 200 米）中觅食。而蓝鲨（Prionace glauca）、锯鲨（Shyrna lewini）和长尾鲨的 ΔHg 和 δHg 值较低，表明这些物种可能将其觅食行为集中在中层带（即 200 至 1000 米深度）的猎物上。总之，THg 浓度的测定为与鲨鱼消费相关的人类健康风险提供了直接证据，而汞同位素组成则是追踪这些海洋捕食者觅食策略的有力工具。总结：结合汞浓度和稳定同位素比值的双重方法，评估了加拉巴戈斯海洋保护区地区常见鲨鱼物种的个体发育和与其消费相关的人类健康风险。
