School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea.
VNU University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Hanoi, Vietnam.
Environ Geochem Health. 2020 Dec;42(12):4141-4158. doi: 10.1007/s10653-020-00611-5. Epub 2020 Jun 6.
Nui Phao mine in Thai Nguyen Province, Vietnam, is the second-largest tungsten (W) open-pit mine in the world, but the level of environmental impacts is not well known. In order to examine the heavy metal contamination in the ecosystem of this mining area, we analyzed six trace elements (As, Cd, Cr, Cu, Pb and Zn) in the collected soil samples. The analytical results showed that all the soil samples were contaminated by Cd and As. Most of the soil samples were contaminated by As (mean value 50.93 ± 55.44 mg/kg) and Cd (mean value 15.22 ± 9.51 mg/kg), which figures are up to 16 and 23 times higher, respectively, compared with the Vietnamese soil quality standard for agriculture (QCVN 03-MT:2015/BTNMT) of 15 mg/kg for As and 1.5 mg/kg for Cd. Contamination factor (CF), enrichment factor (EF), geo-accumulation index (Igeo), principal component analysis (PCA) and hierarchical clustering analysis (HCA) were used to identify the influence of mining activity in the contamination. The CF, EF, pollution index (PI) and Igeo indicated that this area was extremely polluted by Cd, severely to moderately-heavily polluted by As and slightly to moderately polluted by other elements such as Cr, Cu, Pb and Zn. The PCA and HCA results also attribute the source of As, Pb and Zn contamination and enrichment of Cd, Cr and Cu in the study area to Nui Phao mining activities. The PI and contamination degree (C) values of soil quality indicate that the study area was contaminated with particular reference to Cd and As and the level of contamination was decreased in the order of Pb > Cr > Cu > Zn. The study area had high potential ecological risk, and the carcinogenic risk value was higher than the acceptable value (1 × 10 to 1 × 10). This means that the local resident health is strongly affected by Nui Phao mining activities both directly and indirectly via food consumption, when rice plant grown in the paddy field is the dominant crop in the study area.
越南太原省努伊保矿是世界上第二大露天钨矿，但该矿的环境影响程度尚不清楚。为了研究该矿区生态系统中的重金属污染，我们分析了采集的土壤样本中的六种痕量元素（砷、镉、铬、铜、铅和锌）。分析结果表明，所有土壤样本均受到镉和砷的污染。大多数土壤样本受到砷（平均值 50.93±55.44mg/kg）和镉（平均值 15.22±9.51mg/kg）的污染，这两个数值分别比越南农业土壤质量标准（QCVN 03-MT：2015/BTNMT）规定的 15mg/kg 砷和 1.5mg/kg 镉高出 16 倍和 23 倍。污染因子（CF）、富集因子（EF）、地积累指数（Igeo）、主成分分析（PCA）和层次聚类分析（HCA）用于识别采矿活动对污染的影响。CF、EF、污染指数（PI）和 Igeo 表明，该地区受镉污染极为严重，受砷污染严重至中度严重，受铬、铜、铅和锌等其他元素污染轻度至中度。PCA 和 HCA 结果还表明，研究区的砷、铅和锌污染和镉、铬和铜的富集源自努伊保矿开采活动。土壤质量的 PI 和污染程度（C）值表明，该研究区受到 Cd 和 As 的特别污染，污染程度按 Pb>Cr>Cu>Zn 的顺序降低。研究区具有较高的潜在生态风险，致癌风险值高于可接受值（1×10 至 1×10）。这意味着当地居民的健康受到努伊保矿开采活动的直接和间接影响，尤其是当稻田中种植的水稻是研究区的主要作物时。
