Abstract Despite numerous existing publications, the fate of mercury (Hg) in ASGM-affected tropical aquatic systems remains uncertain. This is driven by an incomplete understanding of the factors controlling Hg distribution and transport in tropical ecosystems. The review of existing Hg research into ASGM indicated that hydrology exerts major control on the final sink of Hg in tropical rivers. Total Hg concentrations in river water increase during high discharge events due to increased erosion and Hg export from soils. Geochemical composition and grain-size distribution strongly control Hg concentrations and distribution in sediment and soils. This review highlights the absence of standardized protocols for investigating ASGM-related Hg pollution, and that the applied research methodologies are often unsuitable for adequately assessing the processes involved. We underline the need to consider an extensive suite of biogeochemical, physical and hydrological information when investigating the final sink and risks of ASGM-related Hg. Standardized and accurate research methodologies, applicable to the challenges presented by these tropical environments, would greatly ease not only data comparability and synthesis between studies, but also help to differentiate between anthropogenic and natural Hg. Establishing background values in tropical regions is also imperative for accurate quantifications of Hg enrichment levels in ASGM-affected sites.

中文翻译：

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热带河流手工和小规模金矿开采中汞的归宿：水文和生物地球化学控制。批判性审查

摘要 尽管现有出版物众多，但受 ASGM 影响的热带水生系统中汞 (Hg) 的归宿仍不确定。这是由于对热带生态系统中控制汞分布和运输的因素的不完全了解造成的。对现有 ASGM 汞研究的回顾表明，水文对热带河流中汞的最终汇起到主要控制作用。在高排放事件期间，由于土壤侵蚀和汞输出增加，河水中的总汞浓度会增加。地球化学成分和粒度分布强烈控制着沉积物和土壤中的汞浓度和分布。该审查强调缺乏用于调查 ASGM 相关汞污染的标准化协议，并且应用研究方法通常不适合充分评估所涉及的过程。我们强调在调查 ASGM 相关汞的最终汇和风险时，需要考虑广泛的生物地球化学、物理和水文信息。适用于这些热带环境带来的挑战的标准化和准确的研究方法不仅将大大简化研究之间的数据可比性和综合，而且有助于区分人为汞和自然汞。在热带地区建立背景值对于准确量化受 ASGM 影响地点的汞富集水平也必不可少。调查 ASGM 相关汞的最终汇和风险时的物理和水文信息。适用于这些热带环境带来的挑战的标准化和准确的研究方法不仅将大大简化研究之间的数据可比性和综合，而且有助于区分人为汞和自然汞。在热带地区建立背景值对于准确量化受 ASGM 影响地点的汞富集水平也必不可少。调查 ASGM 相关汞的最终汇和风险时的物理和水文信息。适用于这些热带环境带来的挑战的标准化和准确的研究方法不仅将大大简化研究之间的数据可比性和综合，而且有助于区分人为汞和自然汞。在热带地区建立背景值对于准确量化受 ASGM 影响地点的汞富集水平也必不可少。