Mercury contamination is a widespread phenomenon that impacts ecosystems worldwide. Artisanal Small Scale Gold Mining (ASGM) activities are responsible for more than a third of atmospheric Hg emission. Due to Hg toxicity and its broad and elevated prevalence in the environment resulting from ASGM activities in the tropics, its biomonitoring is essential to better understand the availability of its methylmercury (MeHg) form in the environment. The Minamata Convention was ratified with the objective to “protect human health and the environment from anthropogenic emissions and releases of mercury compounds”. Biomagnification of MeHg occurs through the trophic food web, where it biomagnifies and bioaccumulates in top predators. To monitor environmental MeHg contamination, studies have evaluated the use of living organisms; however, reptiles are among the least documented vertebrates regarding MeHg exposure. In this review we evaluate the use of crocodylians for Hg biomonitoring in tropical ecosystems. We found that out of the 28 crocodiles species, only 10 have been evaluated regarding Hg contamination. The remaining challenges when using this taxon for Hg biomonitoring are inconsistencies in the applied methodology (e.g., wet versus dry weight, tissues used, quantification method). However, due to their life history traits, crocodylians are particularly relevant for monitoring MeHg contamination in regions where ASGM activities occur. In conclusion and given their ecological and socio-economic importance, crocodylians are at great risk of MeHg contamination and are excellent bioindicators for tropical ecosystems.

汞污染是一种影响全球生态系统的普遍现象。手工小规模金矿开采 (ASGM) 活动造成大气汞排放量的三分之一以上。由于汞毒性及其在热带地区的手工和小规模采金活动导致其在环境中广泛且普遍存在，因此对其生物监测对于更好地了解其甲基汞 (MeHg) 形式在环境中的可用性至关重要。《水俣公约》的批准目的是“保护人类健康和环境免受汞化合物的人为排放和释放”。甲基汞的生物放大作用通过营养食物网发生，在顶级捕食者体内进行生物放大和生物积累。为了监测环境甲基汞污染，研究评估了活生物体的使用；然而，爬行动物是有关甲基汞暴露记录最少的脊椎动物之一。在这篇综述中，我们评估了鳄鱼在热带生态系统中用于汞生物监测的用途。我们发现，在 28 种鳄鱼中，只有 10 种接受了汞污染评估。使用该分类单元进行汞生物监测时剩下的挑战是应用方法的不一致（例如，湿重与干重、使用的组织、量化方法）。然而，由于鳄鱼的生活史特征，鳄鱼对于监测手工和小规模采金活动发生地区的甲基汞污染特别重要。总之，鉴于其生态和社会经济重要性，鳄鱼面临着甲基汞污染的巨大风险，并且是热带生态系统的极好的生物指示剂。