School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, PR China; School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; Technology and Development Center for Petrochemical Pollution Control and Resources Utilization of Guangdong Universities, Maoming 525000, PR China.
School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China.
Ecotoxicol Environ Saf. 2018 Nov 30;164:474-483. doi: 10.1016/j.ecoenv.2018.08.063. Epub 2018 Aug 23.
Fate of metallic elements and their migration mechanisms in a waste mud impoundment and affected downstream were assessed. Physicochemical and mineralogical methods combined with PHREEQC calculation, statistical analysis and review of relevant literatures were employed. Results showed that the waste in mud impoundment had been severely weathered and acidized. Metallic elements exhibited high mobility and activity, with a mobility ranking order of Cd > Zn > Mn > Cu ≈ Cr > As ≈ Pb. Hydraulic transportation originating from elevation variation was the most important driving force for metallic elements migration. Although damming standstill was considered as an effective strategy for controlling coarse suspended particulate pollutants, metallic elements were still transported to the Hengshi River in both dissolved phase and fine suspended particle phase accompanied by the overflow of acid mine drainage. The concentrations of dissolved metallic elements were attenuated significantly along the Hengshi River within 41 km stretch. Precipitation/ co-precipitation of iron oxyhydroxides, especially schwertmannite, ferrihydrite and goethite minerals, were established as the most critical processes for metallic elements attenuation in river water. Accompanied by metals migration in the river, two pollution sensitive sites with notably high content of metals in the stretch of S6-S8 and S10, were identified in gently sloping river stretch.
评估了废渣坝中金属元素的命运及其在受影响的下游的迁移机制。采用物理化学和矿物学方法，并结合 PHREEQC 计算、统计分析和相关文献回顾。结果表明，废渣坝中的废物已经严重风化和酸化。金属元素具有高迁移性和活性，其迁移性顺序为 Cd > Zn > Mn > Cu ≈ Cr > As ≈ Pb。由高程变化引起的水力输送是金属元素迁移的最重要驱动力。尽管大坝停止运行被认为是控制粗悬浮颗粒物污染物的有效策略，但随着酸性矿山排水的溢出，金属元素仍以溶解相和细悬浮颗粒相的形式被输送到横石河。在 41 公里长的横石河范围内，溶解态金属元素的浓度显著降低。铁氧化物的沉淀/共沉淀，特别是水铁矿、针铁矿和针铁矿矿物，被确定为河水中金属元素衰减的最关键过程。伴随着金属元素在河流中的迁移，在坡度较缓的 S6-S8 和 S10 段，发现了两个污染敏感点，该段金属元素含量明显较高。
