受酸性矿山废水影响河流水体与沉积物中重金属污染及评价的研究已有大量报道，而缺乏对这类水体悬浮物重金属污染研究．选择受广东大宝山采矿废水影响的横石河为研究对象，研究该河流悬浮物中6种重金属元素（ Mn、Cu、Zn、As、Cd和Pb）的浓度空间分布，采用地累积指数法和潜在生态危害指数法评价重金属生态风险，结合悬浮物组分SEM／XRD表征来进一步解析污染特征及迁移转化机理．结果表明，横石河悬浮物重金属污染严重，主要来源于大宝山采矿废水， Mn、Cu、Zn、As、Cd、Pb 起始浓度分别高达1470、101．6、12169、174．9、412．2、873．7 mg·kg－1，且重金属浓度沿程呈逐渐降低趋势，与悬浮物含量呈显著正相关；悬浮物中重金属污染处于极强风险等级，单个元素Cd严重污染频率为83．33％，对RI贡献平均超90％，各元素潜在风险大小为：Cd ＞Zn＞As＞Pb＞Cu＞Mn；横石河悬浮物初始矿物成分以施氏矿物为主，随着河流的迁移，其逐渐向更为稳定的针铁矿和水铁矿转化，这种矿物组成及转化决定了重金属的分布特征．
There have been a large number of reports on analyzing and assessing heavy metal pollution in river water and sediment affected by acid mine drainage ( AMD) , while work on heavy metal pollution in suspended solids is scarce. Hengshi River, which was polluted by the AMD from Dabaoshan mine, Guangdong Province, was elected as the studied river. Heavy metal ( Mn, Cu, Zn, As, Cd and Pb) concentrations in the suspended solids were analyzed to demonstrate the spatial characteristics. The ecological risk of heavy metals were evaluated using geo?accumulation index and potential ecological risk index. And the components variation of the suspended solids were characterized using SEM and XRD to further analyze the pollution characteristics and migration
mechanism. Results showed that the suspended solids of Hengshi river were heavily polluted by heavy metals, and the main source should be the AMD from Dabaoshan mine. The initial contents of Mn, Cu, Zn, As, Cd and Pb were 1470,101. 6, 12169, 174. 9, 412. 2 and 873. 7 mg·kg-1, respectively. Moreover, the heavy metal concentrations gradually reduced along with the distance, and they had significantly positive relation with the content of suspended solids. The potential ecological risk of heavy metals in the suspended solids of Hengshi River was at a extremely high level, in which Cd pollution was most serious because its severe pollution frequency was as high as 83.33% and the contribution for RI was more than 90% on average. The order of potential risk for each element was Cd > Zn >As >Pb >Cu >Mn. The initial mineral composition in the suspended solids of Hengshi River was mainly schwertmannite, which gradually transformed to more stable goethite and ferrihydrite along with the migration. Such mineral composition and transformation determine the distribution characteristics of heavy metals.
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