黄骅市土壤重金属空间变异特征及污染评价

Assessment on Spatial Variability and Pollution of the Heavy Metal in Soil of Huanghua City

为研究工业和经济高速发展对环渤海滨海生态脆弱区土壤质量的影响,以黄骅市为研究区,利用地统计学方法对黄骅市表层土壤中的Pb,Hg,Cd,Cr,As,Cu,Zn,Ni共8种重金属空间分布特点和污染状况进行了分析。结果表明:(1)Pb,Cd,Cu元素样点平均含量超过河北省土壤背景值,其他元素含量平均值均未超过,所有元素含量平均值都在国家土壤质量二级标准的范围内。(2)根据变异函数拟合发现,Pb,Hg,Cd,Cr,As,Cu共6种元素拟合于指数模型,Zn,Ni两种元素拟合于球状模型;Pb,Cd,Zn基底效应值为25%~75%,空间自相关程度一般,其空间分布格局受到一定外界干扰。其他元素基底效应值均在25%以下,空间自相关性比较强,空间分布格局受外部影响相对较小。(3)根据克里格内插预测发现,Pb,Cd,Cu整体含量高,区域离散分布;Cr,Zn,Ni整体含量低,连续集中分布;As元素成岛状分布,分布集中于几个区域;Hg成散点状分布于黄骅全县。(4)通过计算内梅罗污染指数可知,黄骅市土壤内梅罗污染指数大部分处于1.0~2.0,属于轻度污染状态;吕桥镇中部和齐家务乡西部污染指数最高,属于污染最严重的地区。工业生产和地质环境是影响土壤重金属元素空间分布的主要原因。

To study the influences of the industrial and high-speed economic development on the soil quality in the ecologically fragile zones of Bohai Sea coast,we took Huanghua as the study area to analyze the spatial distribution and contamination situation of Pb,Hg,Cd,Cr,As,Cu,Zn and Ni,through geostatistical method.The results show that the average contents of Pb,Cd,Cu in the samples exceed the background values in Hebei Province,the other elements contents do not exceed the average value,and the average contents of all elements fall into the scope of the national soil quality secondary standards.According to variogram fitting,it is found that six elements of Pb,Hg,Cd,Cr,As,Cu fit to exponential model,and Zn,Ni fit to the spherical model.The basal effects of Pb,Cd,and Zn are between 75%and 25%,and the spatial autocorrelation is general,and the spatial distribution pattern is disturbed by the external environment.Other element matrix effect values are less than 25%,their spatial autocorrelation levels are higher,and the outside environment makes a small influence on their spatial autocorrelation.According to Nemerow pollution index and Kriging interpolation prediction it is found that the contents of Pb,Cd,Cu are high and discretely distribute in the region,the contents of Pb,Cd,Cu are low and continuously distribute in the region.The As as an island continuously distributes in several regions;and the Hg element distributes in Huanghua County as scattered dots.By calculating the Nemerow pollution index,the pollution indexes of soil in Huanghua City are mostly between 2.0and 1.0,which is slightly polluted;the center of the town ofLvqiao and the western part of the town of Qijiawu belong to the most polluted areas,whose pollution indexes are highest.Industrial production and the geological environment are the main reasons for heavy metal element spatial distribution.