淮南市矿区土壤Pb元素含量的空间分布特征

Spatial Distribution Characteristics of Pb in Soils of Mining Areas of Huainan City

为了揭示矿区土壤重金属元素的分布规律及其污染状况,选择对淮南市矿区表层土壤重金属元素Pb进行取样调查,利用地统计学方法对淮南市矿区土壤中Pb元素进行分析研究。通过半方差函数模型拟合来描述Pb的空间结构特征,利用克里金插值法得到土壤中Pb元素污染程度的空间分布图。结果表明,淮南市矿区表层土壤元素Pb呈对数正态分布,Pb元素含量的平均值为50.522 mg/kg,超过了淮南市"十二五"期间研究所获得的背景值(25.1 mg/kg)和Pb元素的土壤基线值(32.41 mg/kg),有2～3个采样点的含量值超过了《国家土壤环境质量标准》(GBl5618—1995)中的二级标准。Pb元素半方差函数模型符合球面模型,具有中等空间相关性。矿区土壤中重金属元素Pb的分布不连续,高值区主要集中在矿区的北部和东部地带。研究区内的采矿活动以及汽车尾气的排放等可能是造成Pb累积和污染的重要因素。

In order to reveal the distribution and pollution of heavy metals in soil,the heavy metal Pb in the top soil of mining area in Huainan city was investigated.Geostatistics method was used to analyze Pb in the soil of mining area in Huainan city.The spatial structure characteristics of Pb was described by semi-variogram function model fitting,and the spatial distribution map of Pb element pollution in soil can be obtained by Kriging interpolation.The results show that the Pb in the topsoil in the mining area of Huainan city is in logarithmic normal distribution.The average content of Pb element is 50.522 mg/kg,which exceeds the background value(25.1 mg/kg)obtained by the research institute during the"Twelfth Five-Year Plan"period in Huainan city and the soil baseline value of Pb element(32.41 mg/kg).The Pb content of 2~3 sampling points exceeds the secondary standard in the National Soil Environmental Quality Standard(GBl5618-1995).The Pb element semivariogram function model conforms to the spherical model and has moderate spatial correlation.The distribution of heavy metal element Pb in the mining area is discontinuous,and the high value areas are mainly concentrated in the northern and eastern parts of the mining area.Mining activities in the study area and emissions from vehicle exhaust may be important factors for Pb accumulation and pollution.