铜尾矿库区土壤与植物中重金属形态分析

Chemical forms of heavy metals in the soils and plants of copper tailings yard.

对铜陵铜尾矿区土壤和植物中重金属形态进行了研究.结果表明,尾矿库区种植地极端贫瘠,有机质含量仅2.6～5.8g.kg-1,而土壤Cu、Cd、Pb、Zn含量皆高于对照土壤,其中Cu含量达809.30～1395.54mg.kg-1,Cd含量达3.25～6.35mg.kg-1,达到对照土壤30～60倍.结缕草和三叶草体内重金属含量与土壤重金属交换态及有机结合态含量成正相关,与碳酸盐结合态、铁锰氧化物结合态成显著或极显著负相关,与矿物态含量相关性不显著.在两种优势植物中,Cu、Zn、Pb均以活性较低的醋酸提取态、盐酸提取态和残渣态为主;Zn在根系和茎叶中,NaCl提取态占有较大比例,而Cd均以NaCl提取态为主.

The study on the chemical forms of heavy metals in the soils and plants at the copper tailings yard in Tongling City indicated that the soils were extremely poor, with organic mater content being 2.6-5.8g·kg^-1, only 1/15 of the control, while their Cu, Cd, Pb and Zn contents were higher than the control, with Cu 809.30-1 395.54mg·kg^-1 and Cd 3.25- 6.35 mg·kg^-1, as 30-60 times as those of the control. The heavy metals contents in Zoysia japonica and Trifolium pratense had a significantly positive correlation with the contents of their exchangeable and organic forms in soils, a significantly or very significantly negative correlation with the forms of Fe-Mn oxides and carbonate, and no correlation with residual form. The main forms of Cu, Zn and Pb in Z. japonica and T. pratense were HAC-and HCl-extractable, and residual. The NaCl-extractable Zn content in the roots, stems and leaves of Z. japonica and T. pratense occupied a higher proportion, while NaCl-extractable Cd was the main form of Cd in both of the plants, not only in their roots but also in their leaves.