云南省木署村高山蔬菜基地土壤重金属污染风险评价研究

Evaluation of Heavy Metal Pollution Risk of Plateau Vegetable Base in Mushu Village, Yunnan Province

评价和控制农田土壤重金属污染对发展云南高原特色蔬菜产业、保障食品安全具有重要意义。选取云南省姚安县前场镇木署村为研究区域,分析样区内土壤重金属Cd,Pb,Ni,Cu,Zn,Cr含量,用单因子污染指数法、内梅罗综合污染指数法和潜在生态风险指数法对样地进行重金属污染评价,通过Arc GIS软件对重金属污染风险进行空间分析。研究表明,样区土壤重金属Cd含量范围为0.07~0.33 mg/kg,平均0.21 mg/kg;Pb含量范围为8.78~26.66 mg/kg,平均22.15 mg/kg;Cu含量范围为22.5~60.31 mg/kg,平均43.3 mg/kg;Zn含量范围为98.59~231.48 mg/kg,平均164.69 mg/kg;Ni含量范围为19.46~52.96 mg/kg,平均35.09 mg/kg;Cr含量范围为94.58~169.45 mg/kg,平均137.08 mg/kg。采样区域各重金属元素含量均低于食用农产品产地环境质量评价标准的限值。根据单项污染指数法和内梅罗污染指数法计算出研究区域综合污染指数,平均为0.86,属于尚清洁级别。研究区域重金属潜在生态危害系数平均值Pb为0.76、Cd为13.91、Cu为4.32、Zn和Cr分别为0.82和1.82。综合评价研究区域重金属的潜在生态危害指数为21.64,重金属潜在生态危害程度属于轻微。结果表明该研究区域可以作为无公害蔬菜基地,对姚安县发展绿色蔬菜产业具有积极意义。

In order to develop vegetables production in Yunnan plateau, it is crucial to evaluate and controlheavy metal pollution of farmland. In this research, the heavy metal soil samples were taken from Mushu Valley,Yao-an county, Yunnan. The heavy metal such as Cd, Pb, Ni, Cu, Zn, Cr in the soil samples were analyzed.Some index methods, such as single factor pollution index, Nemerow comprehensive pollution index, and poten-tial ecological risk index, were used and combined with spatial analysis by Arc GIS. The results reveal the heavymetal contents in mg/kg at 0.07~0.33, 8.78~26.66, 22.5~60.31, 98.59~231.48, 19.46~52.96, and 94.58~169.45 for Cd, Pb, Cu, Zn, Ni, and Cr, respectively, with the averages of 0.21, 22.15, 43.3, 164.69, 35.09, and 137.08.These values for the sampling areas are below the limitation to the evaluation standards of farmland environmen-tal quality for edible agricultural products. With the individual and Nemerow pollution index method, the aver-age of the regionally integrated index values was calculated as of 0.86, also implying that the sampling areas areclean areas. The averaged potential ecological risk coefficients are 0.76, 13.91, 4.32, 0.82 and 1.82 for Pb, Cd,Cu, Zn, and Cr, respectively. The comprehensive potential ecological risk index of heavy metals is 21.64, classi-fied as light potential ecological hazards. The results support the eligibility of Mushu Valley as green vegetablebases. This is meaningful to the sustainable development of social economy in Yao-an County.