陕西商洛某冶炼厂周边农作物重金属污染评价

Evaluation of heavy metal pollution of crops around a smelting plant in Shangluo,Shaanxi

【目的】分析陕西商洛某冶炼厂周边农作物的重金属污染状况,为当地农作物的科学种植提供参考。【方法】以商洛某冶炼厂周边的小麦、玉米、香菜、青菜、菠菜、油菜、葱、蒜等农作物为研究对象,测定农作物中Cu、Zn、Cd、Ni 4种重金属的含量,采用单项污染指数法、综合指数法和聚类分析法评价农作物中4种重金属的污染状况。【结果】研究区农作物中Zn、Cu、Ni含量均未超标,但是青菜、菠菜、油菜、香菜、小麦中出现了不同程度的Cd含量超标现象,由单项污染指数可知,小麦叶、秆及油菜叶和青菜茎Cd轻度污染,香菜茎、叶和青菜叶、菠菜叶中Cd重度污染。由重金属综合污染指数(P综合)可知,麦秆的重金属污染属警戒级,小麦叶、青菜茎、油菜叶属轻度污染,香菜茎、叶和青菜叶、菠菜叶属重度污染,与聚类分析结果一致。农作物中的Cd与Ni、Cd与Zn、Ni与Zn之间存在着极显著的正相关性,说明其污染源可能相似,也可能是复合污染所致。【结论】陕西商洛某冶炼厂周边叶菜类蔬菜吸附重金属能力较强,玉米、大蒜、葱未被重金属污染,适合于研究区种植,而香菜、青菜、菠菜、油菜和小麦已被重金属污染,尤其是香菜、青菜、菠菜不适合于研究区种植。

[Objection] The heavy metal pollution of crops around a smelting plant in Shangluo, Shaanxi was evaluated to provide reference for planting crops with scientific methods. [Method] Contents of four heavy metals, Zn, Cu, Ni, and Cd, in wheat, corn, parsley, green vegetables, spinach, cole, onion, garlic and other crops were determine. Then, the contamination levels were analyzed and evaluated using single pollu- tion index method,comparative index method and clustering analysis. [Result] Contents of Zn, Cu, and Ni in crops did not exceed the standards. Contents of Cd in green vegetables, spinach, cole, parsley and wheat exceeded the standard. According to the single pollution index,wheat leaves,wheat straws,rape leaves and green vegetables stalks had light Cd contamination. Stems and leaves of parsley, green vegetables, and spin- ach leaves were in heavy Cd contamination. According to comprehensive pollution index,the contamination of heavy metals in wheat straw reached the warning line, barley leaves, stems of green vegetables and rape leaves were slightly polluted, while stems and leafs of parsley, leaves of green vegetables and leaves of spin- ach were heavily polluted. All the findings were in accordance with the results of clustering analysis. There were very significant positive correlations between Cd and Ni,Cd and Zn, as well as Ni and Zn,indicating that the pollution sources were similar and the pollution was combined. [Conclusion] The leafy vegetables around the smelting plant had strong capacity of absorbing heavy metals. Corn,garlic and shallot were not polluted and were suitable for planting in the research area. The heavily polluted caraway, green vegeta- bles, spinach, rape and wheat were not suitable for planting in the study area.