农田土壤中铅的形态研究及安全风险评价

Configuration analysis and security risk assessment of lead in farmland soil

研究了农田区域中铅矿区土壤中铅的存在形态,发现铅在土壤中的存在形态按含量大小依次为:残渣态、有机结合态、铁锰氧化物结合态、碳酸盐态、交换态、水溶态。其中,40%以上的铅存在形态具有生物有效性,铅的污染指数远大于1。通过矿区种植卷心菜和茼蒿研究了矿区蔬菜的安全性,结果表明,随着离矿区距离越远,土壤和蔬菜中的铅含量都呈下降趋势,且蔬菜中的铅含量与土壤中的铅浓度呈正相关。蔬菜根的铅含量远高于叶的铅含量,茼蒿较卷心菜高,同时,叶、根的富集系数也相差较大,结果证明,在矿区1 km范围内农田种植的两种蔬菜均不适合食用。

The existence pattern of lead in farmland soil was sudied. According to the size of the content the forms was in the sequence：residual form〉organic combination form〉iron and manganese oxides form〉cabonate form〉exchangeable form〉water soluble form, in which above 40% forms of lead had biological availability, and pollution index of lead was high above 1. The security asseseement of vegetable in mining area was also studied through plenting cabbage and crowndaisy chrysanthemum. The results showed that the farther from the mining area,the lower lead content in soil and vegetable. And the lead content of vegetable was positively related to soil. The content of lead in vegetable roots was far above leaves. The content of lead in crowndaisy chrysanthemum was higher than cabbage.There are different enrichment coefficients of roots and leaves.Reruhs showed that cabbage and crowndaisy chrysanthemum planting in the mining area of 1 km range were not fit for human consumntion.