新疆和甘肃香梨产区土壤重金属残留风险评估

Risk Assessment and Residual Analysis of Heavy Metals in Soil of Korla Fragrant Pear Producing Areas in Xinjiang and Gansu

【目的】分析新疆巴音郭楞蒙古自治州(以下简称巴州)、阿克苏和甘肃酒泉3个香梨产区土壤重金属残留水平,评估新疆、甘肃香梨主产区土壤重金属残留风险大小。【方法】采用微波消解-电感耦合等离子质谱法(ICP-MS),测定铅(Pb)、镉(Cd)、铬(Cr)、镍(Ni)、铜(Cu)、锌(Zn)6种重金属,按照单因子指数法、内梅罗综合污染指数法和生态危害指数法对果园土壤重金属污染及生态危害进行风险评估。【结果】3个产地土壤中各重金属残留水平均低于“食用农产品产地环境质量评价标准”(HJ/T 332-2006)的限值,梨园土壤重金属残留处于可接受的安全水平。与新疆、甘肃土壤背景值相比,梨园土壤中6种重金属呈现不同程度的累积现象,巴州、阿克苏和酒泉3个产区的潜在生态风险指数(RI)分别为57.67、72.14和55.61,均处于低风险水平。但Cd元素是3个产区贡献最大的生态危险因子。【结论】新疆、甘肃产区香梨园土壤重金属总体处于低生态风险水平,属于生产安全区域。

【Objective】The main purpose of this study is to analyze the residual level of six heavy metals Pb,Cd,Cr,Ni,Cu and Zn in the soil of three producing areas of Korla Fragrant Pear,namely Bazhou,Aksu in Xinjiang and Jiuquan in Gansu,and to evaluate the residual risk of heavy metals in the soil of the above main producing areas.【Method】In this study,the residual levels of six heavy metals(Pb,Cd,Cr,Ni,Cu and Zn)in the soil of three pear producing areas in Bazhou,Aksu and Jiuquan City,Gansu Province were analyzed by Inductively Coupled Plasma Mass Spectrometry(ICP-MS).The pollution level of heavy metals in orchard soil was evaluated.At the same time,single factor index(SFI)method,Nemerow comprehensive pollution index(NCPI)method and ecological hazard index(EHI)method were used to carry out ecological hazard risk assessment.【Result】The levels of heavy metal residues in the soils from three producing areas were lower than the limits of Farmland Environmental Qualilty Evalluation Stands for Edible Agricultural Products(HJ/T 332-2006).The levels of heavy metal residues in pear orchard soils were at an acceptable safety level.Compared with soil background values in Xinjiang and Gansu Provinces,the six heavy metals in pear orchards showed different accumulation phenomena.The potential ecological risk index(RI)of Bazhou,Aksu and Jiuquan were 57.67,72.14 and 55.61,respectively,which were at low risk level,but Cd element was the most contributing ecological risk factor in the three producing regions and should deserve our close attention.【Conclusion】The heavy metals in the soil of Korla Fragrant Pear orchards in Xinjiang and Gansu provinces are generally at a low ecological risk level and still belong to the production safety area.