| 钒钛磁铁矿尾矿库复垦土地及周边土壤-玉米重金属迁移富集特征 |
| 摘要点击 2737 全文点击 758 投稿时间：2020-07-21 修订日期：2020-09-16 |
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| 中文关键词 钒钛磁铁矿 重金属污染 土壤 玉米 重金属形态 生物富集系数 承德 |
| 英文关键词 vanadium-titanium magnetite heavy metal pollution soil maize speciation of heavy metals bioconcentration factor Chengde |
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| 中文摘要 |
| 选取承德中部典型钒钛磁铁矿集中区为研究区，分尾矿库复垦土地、尾矿库周边农用地和对照区农用地系统采集了土壤样品和玉米样品各86件，尾矿砂样品50件，矿石和矿石围岩样品33件.在分析土壤和玉米籽实样品Fe、Cu、Ni、Cd、Cr、Pb、Zn、Hg、Ti、Mn和Mo元素含量和土壤、尾矿砂和矿石围岩重金属赋存形态基础上，采用描述性统计、地累积指数、RDA分析和生物富集系数等方法论述了钒钛磁铁矿尾矿库复垦土地及周边土壤和玉米重金属迁移富集特征.结果表明，尾矿库复垦土地及周边土壤元素地累积程度由强至弱为：P > Cu > Fe2O3 > Cr > Ti > V > Ni > Mn > Cd > Zn > Mo > As > Pb > Hg，重金属地累积程度总体属无累积-中度累积水平，土壤Cr和Cu元素超农用地土壤污染筛选值比例为2.32%和1.16%.尾矿库及周边地区玉米籽实Fe、Ti、As、Pb和Mn元素相对较高，对照区玉米籽实Mo、Ni、Cu、Zn、Cd和Cr元素含量相对较高.玉米籽实Pb、As和Ni含量超国家食品限量标准比例分别为18.60%、11.63%和1.16%，均位于尾矿库及其周边区域.尾矿库复垦土地玉米籽实As、Pb、Cd、Cr、Ti和Mn元素生物富集强度相对最高，对照区玉米籽实Cu、Zn和Mo生物富集程度相对较高.尾矿库及周边土壤重金属生物有效态占比Cd元素最高，达50.17%；其次为Ni、Zn和Cu，平均占比为13.61%、13.23%和5.17%.与对照区土壤样品相比，尾矿库复垦土地土壤样品Pb、As和Hg元素表现为总量低，但生物有效性含量和土壤pH高；Cu和Zn总量高但生物有效含量和pH较低特点，使得尾矿库及其周边土壤As和Pb生物富集强度相对增大.在研究矿区尾矿库复垦土地和矿区周边土壤重金属污染生态风险和修复目标值时，宜以重金属生物有效态限值为评价标准. |
| 英文摘要 |
| A total of 86 soil samples, 86 corn kernel samples, 50 tailings samples, and 33 ore rock samples were collected in reclaimed land and surrounding areas of typical vanadium-titanium magnetite tailings located in the Chengde Central Region and analyzed for 14 elements (P, Fe, Cu, Ni, Cd, Cr, Pb, Zn, Hg, Ti, Mn, and Mo) and speciation of heavy metals. This study investigated the bioaccumulation and translocation characteristics of heavy metals in a soil-maize system based on a descriptive statistical analysis, a geological accumulative index, bioconcentration factors, and a redundancy analysis. The results showed that the average accumulation index of surface soil followed an order of P > Cu > Fe2O3 > Cr > Ti > V > Ni > Mn > Cd > Zn > Mo > As > Pb > Hg, while the accumulation level of heavy metals was generally categorized as either no accumulation or moderate accumulation. Compared to China's soil environmental quality standard risk screening values (GB15618-2018), the over-standard rates of Cr and Cu were 2.32% and 1.16%, respectively. The content of Fe, Ti, As, Pb, and Mn in the corn kernels of the tailings and surrounding areas was relatively high, and the content of Mo, Ni, Cu, Zn, Cd, and Cr in the control area was relatively high. The over-standard rates of Ni, Zn, and Cu in the corn kernels were 13.61%, 13.23%, and 5.17% respectively, according to China's national food safety standard limits for contaminants in food (GB 2762-2017). The bioconcentration factors of Fe, Ti, As, Pb, and Mn in the corn kernels of the tailings and the surrounding areas were relatively higher, while the bioconcentration factors of Mo, Ni, Cu, Zn, Cd, and Cr were lower than in control area. The bioactive components of Cd accounted for 50.17%, which was the highest, followed by Ni, Zn, and Cu with average ratios of 13.61%, 13.23%, and 5.17%, respectively. Compared to the control area, the Pb, As and Hg elements in the soil samples of the reclaimed land showed a lower total amount but a higher bioavailability content and soil pH value, while the Cu and Hg elements showed a higher total amount but lower bioavailability content and soil pH value. These differences in total heavy metal concentrations, bioavailability amounts, and soil pH values made the bioconcentration intensity of As and Pb in the tailings reservoir and surrounding area relatively higher. When studying the ecological risk of heavy metal pollution or determining the remediation target value of reclaimed land in a mine tailings reservoir and the soil around the mine area, the bioavailable state limit of heavy metals should be should be taken into account as the evaluation standard. |
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