矿区农用地重金属污染特征及成因分析

Pollution Characteristics and Causes of Heavy Metals in Farmland Soils in a Mine Area

采用网格布点法,在矿区农用地布设48个土壤采样点,对矿区农用地土壤中的Cd、Cu、As、Pb、Zn、Cr、Ni和Hg等8种重金属污染状况进行了评价分析,为矿区农用地的安全利用提供理论依据。采用电感耦合等离子体质谱法(ICP-MS)检测土壤重金属含量,利用单因子污染指数(P_(i))、内梅罗综合污染指数(NIPI)和重金属累积性分析评估了土壤重金属污染状况。结果显示:调查区重金属单因子污染指数顺序为:Cd>Cu>As>Pb>Zn>Cr>Ni>Hg,对土壤中Cu、Pb、Cd和As作累积性分析,Cu的累积系数范围为2.48~7.84,属于中度累积;Cd的累积系数范围为5.1~13.04,属于重度累积。根据重金属污染特征分析,矿区土壤主要污染来源为当地铜、铁、煤矿等开采、金属冶炼等行业的影响,通过大气粉尘和地表废水等途径污染农田。

In order to prove a theoretical basis for the safe utilization of the agricultural land of the mining area,forty-eight soil samples were collected in the agricultural land of the mining area by grid distribution point method,and the contents of Cd,Cu,As,Pb,Zn,Cr,Ni and Hg were tested.The inductively coupled plasma mass spectrometry(ICP-MS)was used to detect the content of heavy metals in soil.The sources and distribution of heavy metals in farmland soils were analyzed using the single factor index,the Nemerow comprehensive pollution index and the accumulative effect of heavy metals in soil.The results showed that the order of single-factor pollution index of heavy metals in the survey area was:Cd>Cu>As>Pb>Zn>Cr>Ni>Hg,and the cumulative analysis of Cu,Pb,Cd and As in soil showed that the cumulative coefficients of Cu ranged from 2.48 to 7.84,which belonged to moderate accumulation;the cumulative coefficients of Cd ranged from 5.1 to 13.04,which belonged to heavy accumulation.According to the analysis of heavy metal pollution characteristics,the main source of soil pollution in the mining area is the influence of local copper,iron,coal mining and metal smelting industries,which pollutes the farmland through atmospheric dust and surface wastewater.