Underestimated heavy metal pollution of the Minjiang River, SE China: Evidence from spatial and seasonal monitoring of suspended-load sediments
Underestimated heavy metal pollution of the Minjiang River, SE China: Evidence from spatial and seasonal monitoring of suspended-load sediments
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中国东南部岷江重金属污染被低估：来自悬浮沉积物空间和季节监测的证据
DOI：
10.1016/j.scitotenv.2020.142586
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发表时间：
2021-01-11
影响因子：
9.8
通讯作者：
Fu, Hanjing
中科院分区：
文献类型：
--
作者：
Fan, Jiayu;Jian, Xing;Fu, Hanjing
以往对经济高度发达、人口众多的中国东南地区河流的评价表明，河流的重金属污染水平多样且相对较低。然而，重金属富集和迁移的控制机制仍然是一个谜。本文以岷江这条中尺度山地河流为研究对象，从河口附近的季节性悬浮颗粒物（SPM）、河床沉积物以及干流和主要支流的SPM样品中获取粒度、矿物学和重金属浓度（Pb、Cd、Cr、Mn、Mo、Zn、V、Co、Ni、Cu）数据。结果表明，SPM样品的颗粒重金属浓度高于成对收集的河床沉积物。上游SPM样品中Cd、Zn、Cr、V、Co、Ni和Cu重金属浓度高于下游区域，而Pb、Mn和Mo浓度不存在这种空间差异。大多数重金属（如Pb和Zn）在汛期浓度较高，在旱季浓度相对较低，显示出水文控制作用。然而，Cr和Mn在一些旱季样品中显示出高浓度，表明偶然的人为输入事件。基于spm的富集系数、累积指数和潜在生态风险指数评价结果表明，岷江流域Pb、Cd、Mo、Zn等颗粒物污染程度为中度至重度，大部分颗粒物重金属具有中度至相当程度的潜在生态风险。我们认为，岷江颗粒物重金属的运输和排放受到自然和人为强迫的双重控制，污染程度比以前所知的要严重。研究结果表明，亚热带山地河流颗粒物重金属排放与沉积物类型和水文特征有关。因此，建议对河流SPM样品进行高时空分辨率的调查，以更好地评估颗粒物重金属污染水平和水生环境状况。(C) 2020 Elsevier B.V.版权所有
Previous assessments on rivers in SE China with highly developed economy and enormous population indicate diverse and relatively low particulate heavy metal pollution levels. However, the controlling mechanisms for heavy metal enrichment and transport remain enigmatic. Here, we target a mesoscale mountainous river, the Minjiang River, and obtain grain size, mineralogical and heavy metal concentration (Pb, Cd, Cr, Mn, Mo, Zn, V, Co, Ni, Cu) data from seasonal suspended particulate matter (SPM) near the river mouth, riverbed sediments and SPM samples from mainstream and major tributaries of the river. The results indicate that SPM samples have higher particulate heavy metal concentrations than riverbed sediments collected in pairs. Heavy metal concentrations of Cd, Zn, Cr, V, Co, Ni and Cu are higher in upstream SPM samples than those in downstream regions, whereas Pb, Mn and Mo concentrations don't show this spatial variation. Most heavy metals (e.g., Pb and Zn) show high concentrations in flood seasons and relatively low concentrations in dry seasons, revealing a hydrologic control. However, Cr and Mn show high concentrations in some dry season samples, suggesting incidental anthropogenic input events. The SPM-based pollution assessments using enrichment factor, geoaccumulation index and potential ecological risk index demonstrate that the Minjiang River ismoderately to strongly polluted by particulate Pb, Cd, Mo and Zn contaminations and most particulate heavy metals havemoderate to considerable potential ecological risks. We contend that transport and discharge of particulate heavy metals by the Minjiang River are controlled by both natural and anthropogenic forcings and the pollution levels are worse than previously known. Our findings suggest that particulate heavymetal discharge by subtropical mountainous rivers is related to sediment types and hydrologic characteristics. Therefore, high-spatiotemporal-resolution investigations on river SPM samples are highly recommended to better evaluate particulate heavymetal pollution levels and aquatic environmental conditions. (C) 2020 Elsevier B.V. All rights reserved.