Department of Thematic Studies - Environmental Change, Linköping University, Linköping SE-58183, Sweden; Linköping University - Guangzhou University Research Center on Urban Sustainable Development, Guangzhou University, Guangzhou CN-510006, China.
Department of Thematic Studies - Environmental Change, Linköping University, Linköping SE-58183, Sweden; Linköping University - Guangzhou University Research Center on Urban Sustainable Development, Guangzhou University, Guangzhou CN-510006, China.
Sci Total Environ. 2020 Jul 1;724:138122. doi: 10.1016/j.scitotenv.2020.138122. Epub 2020 Mar 25.
Dabaoshan Mine Site (DMS) is the largest polymetallic mine in South China. The Hengshi River flowing next to DMS receives acid mine wastes leaching from the tailings pond and run-off from a treatment plant, which flows into the Wengjiang River. This study focuses on spatiotemporal distribution and mobilization of As, Cd, Pb, and Zn along the Hengshi River, groundwater, fluvial sediments, and soils, with a focus on As due to its high toxicity and the fact that mining is one of the main sources of contamination. Geochemical analyses (heavy metals, grain-size, X-ray diffraction, organic carbon and sulfur content) followed by geochemical modeling (PHREEQC) and statistical assessment were done to determine the physicochemical characteristics, toxicity risks, and behavior of heavy metals. Near the tailings pond, heavy metal concentrations in surface water were 2-100 times higher than the Chinese surface water standard for agriculture. Although water quality during the dry season has improved since the wastewater treatment plant started, heavy metal concentrations were high during rainy season. In groundwater, heavy metal concentrations were low and pose little risks. Soils along the Hengshi River were disturbed and they did not show any specific trends. The potential ecological risk of heavy metals was ranked as Cd > As > Cu > Pb > Zn in sediments and Cd > Cu > Pb > As > Zn in soils indicating multi-metal contamination and toxicity. As(III) was the predominant species in surface water during the dry season, whereas As(V) dominated during the rainy season. Arsenic levels in most sites exceeded the Chinese soil standard. Although As is assumed to have a moderate ecological risk in sediments and low risk in soils, anthropogenic activities, such as mining and land-use changes contribute to the release of As and other heavy metals and pose a risk for local residents.
大宝山矿区（DMS）是中国南方最大的多金属矿。毗邻 DMS 的横石水从尾矿库中浸出酸性矿山废水，并从处理厂中流出径流，流入翁江河。本研究重点关注沿横石河、地下水、河流沉积物和土壤中砷、镉、铅和锌的时空分布和迁移，重点关注砷，因为它毒性高，且采矿是主要污染来源之一。进行了地球化学分析（重金属、粒度、X 射线衍射、有机碳和硫含量），然后进行地球化学模拟（PHREEQC）和统计评估，以确定重金属的物理化学特性、毒性风险和行为。在尾矿库附近，地表水的重金属浓度是中国农业地表水标准的 2-100 倍。尽管自污水处理厂启动以来，旱季的水质有所改善，但雨季的重金属浓度仍然很高。在地层水中，重金属浓度较低，风险较小。沿横石河的土壤受到干扰，没有表现出任何特定的趋势。重金属的潜在生态风险在沉积物中被评为 Cd>As>Cu>Pb>Zn，在土壤中为 Cd>Cu>Pb>As>Zn，表明多金属污染和毒性。在旱季，地表水主要以 As(III)为主，而在雨季则以 As(V)为主。大多数地点的砷含量都超过了中国土壤标准。尽管砷被认为在沉积物中具有中等的生态风险，在土壤中风险较低，但人为活动，如采矿和土地利用变化，导致砷和其他重金属的释放，对当地居民构成风险。
