煤矿区土壤中重金属形态及其在茶树不同组织中的含量分布

Distribution Characteristics of Heavy Metals Form in Soil around Coal Mine Area and in Different Tissues of Large-leaved Tea Plant

对勐旺煤矿周边茶园土壤和大叶种茶树不同组织中重金属元素(As、Cd、Co、Cr、Cu、Fe、Mn、Pb、Sb、Sn、Ti和Zn)的含量进行分析.结果表明,茶园土壤为强酸性,土壤中As、Cd和Pb的含量已超出我国农用土壤污染风险筛选值的阈值,且Cd的含量已达2.13 mg/kg远超1.5 mg/kg的风险管制阈值,但茶叶嫩叶中各重金属元素的含量较低,饮用茶叶无健康风险.转移系数计算结果显示,大叶种茶树并非重金属超累积植物,且其具有抗土壤酸化能力强、生长周期长、体型大、重金属耐受性高等特点,因此,大叶种茶树在酸性重金属污染土壤治理和矿山复垦方面依然具有较好的应用前景.

The concentration of heavy metals(As, Cd, Co, Cr, Cu, Fe, Mn, Pb, Sb, Sn, Ti and Zn) in different tissues of large-leaved tea plant and tea garden soil around Mengwang coal mine area were analyzed. The results showed that the soil of tea garden is strongly acidic, and the concentrations of As, Cd and Pb in tea garden soil are higher than the risk screening threshold of agricultural soil quality standards of China, and the concentration of Cd in tea garden soil is 2.13 mg/kg, which is far higher than the risk control threshold of 1.5 mg/kg. However, the concentrations of heavy metals in tender tea leaves are very low, and there are no health risks for drinking tea. The Transfer coefficients(TFs) showed that the large-leaved tea plant is not a heavy metal hyper-accumulator;however, it has the characteristics of strong resistance to soil acidification, long growth cycle, large size and high tolerance to heavy metals, so it still has a good application prospect in the treatment of acid heavy metal soil pollution and mine reclamation.