Dissolved heavy metals (HMs), derived from natural and anthropogenic sources, are an important part of aquatic environment research and gain more international concern due to their acute toxicity. In this study, the geochemistry of dissolved HMs was analyzed in the upper Three Gorges Reservoir (TGR) of the Yangtze River (YZR) watershed to explore their distribution, status, and sources and further evaluate the water quality and HM-related risks. In total, 57 water samples were collected from the main channel and tributaries of the upper TGR. The concentrations of eight HMs, namely V, Ni, Cu, Zn, As, Mo, Cd, and Pb, were measured by ICP-MS. The mean concentrations (in μg/L) of eight HMs decreased in the order: As (1.46), V (1.44), Ni (1.40), Mo (0.94), Cu (0.86), Zn (0.63), Pb (0.03), and Cd (0.01). The concentrations of most HMs were 1.4~8.1 times higher than that in the source area of the YZR, indicating a potential anthropogenic intervention in the upper TGR. Spatially, the concentrations of V, Cu, As, and Pb along the main channel gradually decreased, while the others were relatively stable (except for Cd). The different degrees of variations in HM concentrations were also found in tributaries. According to the correlation analysis and principal component (PC) analysis, three PCs were identified and explained 75.1% of the total variances. combined with the concentrations of each metal, PC1 with high loadings of V, Ni, As, and Mo was considered as the main contribution of human inputs, PC2 (Cu and Pb) was primarily attributed to the contribution of mixed sources of human emissions and natural processes, and Zn and Cd in PC3 were controlled by natural sources. Water quality assessment suggested the good water quality (meeting the requirements for drinking purposes) with WQI values of 14.1 ± 3.4 and 11.6 ± 3.6 in the main channel and tributaries, respectively. Exposure risk assessment denoted that the health effects of selected HMs on the human body were limited (hazard index, HI < 1), but the potential risks of V and As with HI > 0.1 were non-negligible, especially for children. These findings provide scientific support for the environmental management of the upper TGR region and the metal cycle in aquatic systems.

中文翻译：

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汛期长江流域三峡水库上游溶解态重金属地球化学研究

来源于自然和人为来源的溶解重金属 (HMs) 是水生环境研究的重要组成部分，由于其急性毒性而受到更多国际关注。本研究对长江流域上游三峡水库 (TGR) 中溶解的重金属的地球化学进行了分析，以探索其分布、现状和来源，并进一步评估水质和与重金属相关的风险。共采集了三峡上游干流和支流水样57个。通过 ICP-MS 测量了八种重金属的浓度，即 V、Ni、Cu、Zn、As、Mo、Cd 和 Pb。8 种重金属的平均浓度（μg/L）依次降低：As (1.46)、V (1.44)、Ni (1.40)、Mo (0.94)、Cu (0.86)、Zn (0.63)、Pb (0.03) ) 和 Cd (0.01)。大多数HMs的浓度为1.4~8。1 倍于 YZR 源区，表明对上 TGR 的潜在人为干预。空间上，沿主通道的 V、Cu、As 和 Pb 的浓度逐渐降低，而其他相对稳定（Cd 除外）。在支流中也发现了 HM 浓度的不同程度的变化。根据相关分析和主成分 (PC) 分析，确定了三个主成分并解释了总方差的 75.1%。结合每种金属的浓度，V、Ni、As 和 Mo 含量高的 PC1 被认为是人类输入的主要贡献，PC2（Cu 和 Pb）主要归因于人类排放的混合来源和自然过程，PC3 中的 Zn 和 Cd 受天然来源控制。水质评估表明，干流和支流的WQI值分别为14.1±3.4和11.6±3.6，水质良好（满足饮用要求）。暴露风险评估表明，选定的 HMs 对人体的健康影响有限（危害指数，HI < 1），但 HI > 0.1 的 V 和 As 的潜在风险不可忽略，尤其是对儿童。这些发现为上 TGR 区域的环境管理和水生系统中的金属循环提供了科学支持。暴露风险评估表明，选定的 HMs 对人体的健康影响有限（危害指数，HI < 1），但 HI > 0.1 的 V 和 As 的潜在风险不可忽略，尤其是对儿童。这些发现为上 TGR 区域的环境管理和水生系统中的金属循环提供了科学支持。暴露风险评估表明，选定的 HMs 对人体的健康影响有限（危害指数，HI < 1），但 HI > 0.1 的 V 和 As 的潜在风险不可忽略，尤其是对儿童。这些发现为上 TGR 区域的环境管理和水生系统中的金属循环提供了科学支持。