Mercury dynamics in hydroelectric reservoirs have been studied worldwide. In tropical reservoirs, especially in those of the Amazon, the influence of geochemistry on Hg levels along this aquatic system is not well understood. The main objective of the present study was to assess the influence of environmental conditions (physical and chemical water parameters, trace element concentrations of sediment and sediment geochemistry) on mercury levels of sediment along the Balbina Reservoir (Amazon basin, Brazil). Sediment was collected along the reservoir and in the main tributaries in May 2015 (n = 10). These samples were assessed for labile iron (LFe), manganese (LMn), aluminum (LAl) and mercury (LHg) concentrations, total mercury (THg) concentrations, organic matter (OM) content, and granulometry. Concentrations in the sediment were 4–212 (LFe), 2–460 (LAl), 180–613 (LMn), < detection limit–256 (LHg), and 12–307 μg kg⁻¹ dry weight (THg). In general, these concentrations decreased along the reservoir from upstream to downstream, reaching the lowest concentrations in the middle of the lake, and they increased in the sampling points near the dam. The lability and concentrations of mercury were influenced by the concentrations of LFe, LMn, LAl, and the granulometry and OM content of the sediment. Altogether, THg concentrations of sediments of the Balbina Reservoir encompass the range of concentrations of other reservoirs or natural lakes in the Amazon basin (from ten to a few hundred μg kg⁻¹ dry weight).

全世界已经研究了水力发电库中的汞动力学。在热带水库中，特别是在亚马逊河水库中，人们对这种水生系统中地球化学对汞含量的影响还知之甚少。本研究的主要目的是评估环境条件（物理和化学水参数，沉积物的微量元素浓度和沉积物地球化学）对沿Balbina水库（巴西亚马逊盆地）的沉积物汞含量的影响。2015年5月，沿水库和主要支流收集了沉积物（n = 10）。对这些样品的不稳定铁（LFe），锰（LMn），铝（LAl）和汞（LHg）浓度，总汞（THg）浓度，有机物（OM）含量和粒度进行了评估。沉积物中的浓度为4–212（LFe），2–460（LAl），180–613（LMn），<检测极限–256（LHg）和12–307μgkg ^-1干重（THg）。通常，这些浓度沿水库从上游到下游降低，在湖泊中部达到最低浓度，而在大坝附近的采样点则增加。LFe，LMn，LAI的浓度以及沉积物的粒度和OM含量会影响汞的不稳定性和汞浓度。总的来说，巴尔比纳水库的沉积物THg浓度涵盖了亚马逊河流域其他水库或天然湖泊的浓度范围（从10到数百μgkg ^-1干重）。