| 引用本文: | 钟桥辉，王煜煊，任世兴，周玉婷，吴洋，殷美玲，韦旭东，白秀明，王津，张兆峰，刘娟.2020.某硫铁矿区废水池沉积物剖面中重金属化学形态分布和环境污染评价[J].地球环境学报,11(5):524-535 |
| ZHONG Qiaohui, WANG Yuxuan, REN Shixing, ZHOU Yuting, WU Yang, YIN Meiling, WEI Xudong, BAI Xiuming, WANG Jin, ZHANG Zhaofeng, LIU Juan.2020.Speciation distribution and environmental pollution assessment of heavy metals in sediments from wastewater pond of a pyrite mine[J].Journal of Earth Environment,11(5):524-535 |
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| 某硫铁矿区废水池沉积物剖面中重金属化学形态分布和环境污染评价 |
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钟桥辉，王煜煊，任世兴，周玉婷，吴洋，殷美玲，韦旭东，白秀明，王津，张兆峰，刘娟
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1. 中国科学院广州地球化学研究所 同位素地球化学国家重点实验室，广州 510640
2. 中国科学院大学，北京 100049
3. 广州大学 珠江三角洲水质安全与保护教育部重点实验室，广州 510006
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| 摘要: |
| 矿山开采是造成环境重金属污染的重要途径，揭示重金属在污染区的富集特征及潜在生态效应对重金属污染防治有重要意义。以粤西某硫铁矿区废水池沉积物剖面为研究对象，采用电感耦合等离子质谱仪和分级提取法分析底泥中Tl、Cr、Ni、Co与Cd总量和各化学形态的分布特征及生态风险，并结合矿物组成分析阐明富集及迁移机制。结果表明：底泥中Cd含量远超我国土壤背景值，且Cd主要以弱酸可交换态的形式存在；Tl含量同样远超我国土壤背景值，以残余态的形式为主；Cr和Ni含量均略高于我国土壤背景值，也主要以残余态的形式存在；Co含量小于我国土壤环境背景值，具有较大的弱酸可交换态比例。综合富集因子法和风险评价指数分析，底泥中Cd具有很强的环境潜在危害性；Tl具有强的环境潜在危害性；Cr和Ni具有中等程度的环境潜在危害性；Co没有环境潜在的危害。硫铁矿区废水池底泥是重金属（Cd、Tl、Ni和Cr）重要的汇和潜在二次污染源。硫铁矿区废水池底泥中Cd和Tl高度富集，Ni和Cr具有低—中等程度的富集，废水池底泥的污染防治与资源回收同样值得思考关注。 |
| 关键词: 废水池底泥 重金属 分级提取 环境污染评价 |
| DOI：10.7515/JEE192049 |
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| 基金项目:国家自然科学基金（41573008，41873015）；广东省自然科学基金（2017A030313247）；广州大学青年拔尖人
才项目（BJ201709）；第17届“挑战杯”全国大学生课外学术科技作品竞赛 |
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| Speciation distribution and environmental pollution assessment of heavy metals in sediments from wastewater pond of a pyrite mine |
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ZHONG Qiaohui, WANG Yuxuan, REN Shixing, ZHOU Yuting, WU Yang, YIN Meiling, WEI Xudong, BAI Xiuming, WANG Jin, ZHANG Zhaofeng, LIU Juan
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1. State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
3. Innovation Center and Key Laboratory of Waters Safety & Protection in the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China
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| Abstract: |
| Background, aim, and scope Mining/smelting is one of the important anthropogenic activities leading to heavy metal pollution in the environment. It is critical to investigate the enrichment characteristics and potential ecological effects of heavy metals in polluted areas for the prevention and control of pollution. In a pyrite mining area in western Guangdong, the wastewater produced by the separation and cleaning process of pyrite was discharged into a wastewater pond along a ditch. When the pond was full, the water overflowed into the stream, merged into Nanshan River, and finally entered Xijiang River. Herein, the contents, the main mineral composition and chemical fractionation of heavy metals in a sediment profile from the pyrite wastewater pond were studied. Materials and methods A sediment core with a total length of 30 cm was taken using a column sampler (6 cm in diameter) from the wastewater pond in the pyrite area. The sediment core was divided into 0—2 cm, 2—4 cm, 4—18 cm, 18—24 cm and 24—30 cm, respectively, depending on the color distinction. The sediment samples were air-dried to a constant weight. The dried sediment samples were ground in an agate mortar and sieved to obtain ＜2 mm fractions, then well homogenized for further analysis. The main elements in the sediment samples were tested by X-ray fluorescence. The samples were characterized by semi-quantitative X-ray diffraction for analyzing mineralogical compositions. To determine the total heavy metal contents, the sediment samples were digested using a mixture of concentrated HNO3, HF, and HClO4 on a hotplate at 150℃. The chemical fractionation of heavy metals were analyzed using sequential extraction IRMM (Institute for Reference Materials and Measurements). All the samples were finally measured with high precision inductively coupled plasma mass spectrometry (ICP-MS, Perkin-Elmer, Elan 6000). Results The X-ray diffraction results showed that the bulk mineralogy of the sediments was dominated by quartz, muscovite, kaolinite and iron oxides (such as goethite, magnetite), with minor amounts of manganese oxide (e.g. manganese dioxide, iron manganate), pyrite, calcite and dipotassium chromate. The X-ray fluorescence results showed that the main elements in the sediment were Si and Fe, accounting for up to 85%. The variation range of Al and total S content was 2.05%—4.60% and 2.82%—8.13%, respectively. In the sediment profile, the Cd content in the sediment far exceeded the background value of the Chinese soil (BVCS), and the major part of Cd was generally presented in the weak acid exchangeable fraction. The Tl content also far outweighed the BVCS, but it was mainly contained in the residual fraction. Both Cr and Ni contents were slightly higher than the BVCS, and primarily contained in the residual fraction. The Co content was generally lower than the BVCS, and dominantly presented in weak acid exchangeable fraction. Discussion In the sediment profile, the Cd content reached the level of extremely serious environmental pollution, and most of them existed in the weak acid exchangeable fraction, showing strong environmental potential hazard. The mobile fraction of Tl in the sediment profile was relatively small, but an obvious enrichment of Tl was found for depth profiles. Therefore, the Tl in the sediment profile still had strong environmental potential hazard. Cr and Ni were contaminated from moderate to severe levels; considering that their mobile fractions were relatively small, there was moderate environmental potential hazard for these two metals. While the Co content was significantly smaller than the BVCS, the metal had no potential environmental hazard. Conclusions Tl, Cd, Cr and Ni were obviously enriched in the sludge of the wastewater pond in the pyrite mine area, showing various heavy metal pollution characteristics. Based on the comprehensive risk assessment code, Cd and Tl were in the status of serious environmental pollution, and Cr and Ni were considered moderate environmental pollution, while Co had no environmental pollution risk. Recommendations and perspectives The sediments in the pyrite mine wastewater pond are a sink of heavy metals (typical of Cd, Tl, Ni and Cr) and also an important secondary source of pollution. The pollution prevention and resource recovery of the sediments in the wastewater pond are also worthy of consideration. |
| Key words: wastewater pond sediment heavy metal fractional extraction environmental pollution assessment |
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