Xie Yingying, Lu Guining, Yang Chengfang, Qu Lu, Chen Meiqin, Guo Chuling, Dang Zhi
School of Environment and Energy, South China University of Technology, Guangzhou, China.
The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou, China.
PLoS One. 2018 Jan 5;13(1):e0190010. doi: 10.1371/journal.pone.0190010. eCollection 2018.
Trace-element concentrations in acid mine drainage (AMD) are primarily controlled by the mineralogy at the sediment-water interface. Results are presented for a combined geochemical and mineralogical survey of Dabaoshan Mine, South China. Developed sequential extraction experiments with the analysis of the main mineralogical phases by semi-quantitative XRD, differential X-ray diffraction (DXRD) and scanning electron microscopy (SEM) were conducted to identify the quantitative relationship between iron minerals and heavy metals. Results showed that schwertmannite, jarosite, goethite and ferrihydrite were the dominant Fe-oxyhydroxide minerals which were detected alternately in the surface sediment with the increasing pH from 2.50 to 6.93 along the Hengshi River. Decreasing contents of schwertmannite ranging from 35 wt % to 6.5 wt % were detected along the Hengshi River, which was corresponding to the decreasing metal contents. The easily reducible fractions exert higher affinity of metals while compared with reducible and relatively stable minerals. A qualitative analysis of heavy metals extracted from the sediments indicated that the retention ability varied: Pb > Mn > Zn > As ≈ Cu > Cr > Cd ≈ Ni. Results in this study are avail for understanding the fate and transport of heavy metals associated with iron minerals and establishing the remediation strategies of AMD systems.
酸性矿山排水（AMD）中的微量元素浓度主要受沉积物 - 水界面处的矿物学控制。本文给出了中国南方大宝山矿的地球化学与矿物学综合调查结果。开展了顺序提取实验，并通过半定量XRD、微分X射线衍射（DXRD）和扫描电子显微镜（SEM）对主要矿物相进行分析，以确定铁矿物与重金属之间的定量关系。结果表明，施韦特曼石、黄钾铁矾、针铁矿和水铁矿是主要的铁羟基氧化物矿物，沿着横石河，随着pH值从2.50增加到6.93，这些矿物在表层沉积物中交替被检测到。沿着横石河检测到施韦特曼石含量从35 wt%降至6.5 wt%，这与金属含量的降低相对应。与可还原和相对稳定的矿物相比，易还原部分对金属具有更高的亲和力。对沉积物中提取的重金属进行的定性分析表明，其保留能力各不相同：Pb > Mn > Zn > As ≈ Cu > Cr > Cd ≈ Ni。本研究结果有助于理解与铁矿物相关的重金属的归宿和迁移，并制定酸性矿山排水系统的修复策略。
