Environmental contaminants affect ecosystems worldwide and have deleterious effects on biota. Non-essential mercury (Hg) and lead (Pb) concentrations are well documented in some taxa and are described to cause multiple detrimental effects on human and wildlife. Additionally, essential selenium (Se) is known to be toxic at high concentration but, at lower concentrations, Se can protect organisms against Hg toxicity. Crocodilians are known to bioaccumulate contaminants. However, effects of these contaminants on physiological processes remain poorly studied. In the present study, we quantified Hg, Pb and Se concentrations in spectacled caimans (Caiman crocodilus) and investigated effects of these contaminants on several physiological processes linked to osmoregulatory, hepatic, endocrine and renal functions measured through blood parameters in 23 individuals. Mercury was related to disruption of osmoregulation (sodium levels), hepatic function (alkaline phosphatase levels) and endocrine processes (corticosterone levels). Lead was related to disruption of hepatic functions (glucose and alanine aminotransferase levels). Selenium was not related to any parameters, but the Se:Hg molar ratio was positively related to the Na⁺ and corticosterone concentrations, suggesting a potential protective effect against Hg toxicity. Overall, our results suggest that Hg and Pb alter physiological mechanisms in wild caimans and highlight the need to thoroughly investigate the consequences of trace element contamination in crocodilians.

环境污染物影响全世界的生态系统，并对生物群产生有害影响。一些分类群中的非必需汞 (Hg) 和铅 (Pb) 浓度有据可查，并被描述为对人类和野生动物造成多种不利影响。此外，已知必需硒 (Se) 在高浓度下有毒，但在较低浓度下，Se 可以保护生物体免受汞中毒。众所周知，鳄鱼会生物累积污染物。然而，这些污染物对生理过程的影响仍然缺乏研究。在本研究中，我们量化了眼镜凯门鳄（Caiman crocodilus) 并研究了这些污染物对与渗透调节、肝、内分泌和肾功能相关的几个生理过程的影响，这些生理过程通过 23 个人的血液参数测量。汞与渗透调节（钠水平）、肝功能（碱性磷酸酶水平）和内分泌过程（皮质酮水平）的破坏有关。铅与肝功能（葡萄糖和丙氨酸氨基转移酶水平）的破坏有关。硒与任何参数无关，但 Se:Hg 摩尔比与 Na ⁺呈正相关和皮质酮浓度，表明对汞毒性的潜在保护作用。总的来说，我们的结果表明 Hg 和 Pb 改变了野生凯门鳄的生理机制，并强调了彻底调查鳄鱼微量元素污染后果的必要性。