Lemaire Jérémy, Mangione Rosanna, Caut Stéphane, Bustamante Paco
Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria.
Consejo Superior de Investigaciones Cientificas (CSIC), Departamento de Etologia y Conservacion de la Biodiversidad, Estacion Biologica de Doñana, C/ Americo Vespucio, s/n (Isla de la Cartuja), E-41092, Sevilla, Spain.
Heliyon. 2024 Mar 29;10(7):e28859. doi: 10.1016/j.heliyon.2024.e28859. eCollection 2024 Apr 15.
Freshwater ecosystems are among the most important ecosystems worldwide, however, over the last centuries, anthropogenic pressures have had catastrophic effects on them. Mercury (Hg) is one of the main environmental contaminants which globally affect ecosystems and particularly freshwater wildlife. While Hg originates from natural sources, anthropogenic activities such as agriculture, biomass combustion, and gold mining increase its concentrations. Gold mining activities are the main drivers of Hg emission in tropical ecosystems and are responsible for up to 38% of global emissions. Once in its methylated form (MeHg), mercury biomagnifies through the trophic chain and accumulates in top predators. Due to the toxicity of MeHg, long-lived predators are even more subjected to chronic effects as they accumulate Hg over time. In the present study we quantified Hg contamination in two top predators, the Black caiman and the Agami heron , and in their prey in the Kaw-Roura Nature Reserve in French Guiana and evaluated the biomagnification rate in the trophic chain. Our results show that despite a TMF in the range of others in the region (4.38 in our study), top predators of the ecosystem present elevated concentrations of Hg. We have found elevated Hg concentrations in the blood of adult Black caiman (2.10 ± 0.652 μg g dw) and chicks of Agami heron (1.089 ± 0.406 μg g dw). These findings highlight the need to better evaluate the potential impact of Hg in freshwater top predators, especially regarding reprotoxic effects.
淡水生态系统是全球最重要的生态系统之一。然而，在过去几个世纪里，人为压力对它们造成了灾难性影响。汞（Hg）是全球影响生态系统尤其是淡水野生动物的主要环境污染物之一。虽然汞源于自然来源，但农业、生物质燃烧和金矿开采等人为活动会增加其浓度。金矿开采活动是热带生态系统中汞排放的主要驱动因素，占全球排放量的38%。一旦汞以甲基汞（MeHg）的形式存在，它就会通过营养链进行生物放大，并在顶级捕食者体内积累。由于甲基汞的毒性，长寿的捕食者随着时间的推移积累汞，更容易受到慢性影响。在本研究中，我们对法属圭亚那卡鲁拉自然保护区的两种顶级捕食者——黑凯门鳄和绿鹭及其猎物中的汞污染进行了量化，并评估了营养链中的生物放大率。我们的结果表明，尽管本研究中的生物放大系数（TMF）与该地区其他研究结果处于同一范围（本研究中为4.38），但该生态系统的顶级捕食者体内汞浓度仍然很高。我们发现成年黑凯门鳄血液中的汞浓度升高（2.10±0.652μg/g干重），绿鹭雏鸟血液中的汞浓度也升高（1.089±0.406μg/g干重）。这些发现凸显了更好地评估汞对淡水顶级捕食者潜在影响的必要性，尤其是对生殖毒性影响方面。
