特色果品种植区土壤重金属空间变异规律研究——以河北省沧州为例

Spatial Variability of Soil Heavy Metals in Characteristic Fruit Planting Area:a Case Study in Cangzhou

以沧县、献县、泊头和黄骅为研究区,采用地理信息系统(GIS)和地统计学相结合的方法,研究了该特色果品种植区的表层1470个样点土壤全量Cu、Zn、Pb、Ni、Cd、Cr、Hg、As元素的空间分异规律及其影响因子。结果表明:除Hg、Cr、Pb外其他5种元素的最大值均超出土壤环境质量一级标准,说明研究区还存在一定程度的重金属污染。变异系数分析表明,Cr最小,为0.10;Hg最高,为0.40。8种重金属之间均为1%水平显著正相关关系;块金效应分析结果显示Ni和Cr空间相关性较强,而其余6种重金属则呈现中等强度空间相关性。而从变程来看,Cd最大,为108.80 km,说明该元素与土壤母质关系密切,Cr最小,仅为25.99 km,说明该元素空间自相关距离大于取样间隔距离。8种重金属空间分布结果表明,整体呈现西部高于东部的特征;其原因除母质等自然因素外,人为因素如工业发达、交通尾气和农药化肥施用等也是影响其空间分布的重要原因。

Geographic information system（GIS） combined with geostatistics was applied to reveal the spatial variability of soil heavy metals（Cu,Zn,Pb,Ni,Cd,Cr,Hg and As） and its affecting factors based on data from 1470 points of surface soil（0-20 cm） samples in Cangzhou of Hebei Province.The results showed that the content exceeded the national soil quality criteria with the exception of Hg,Cr and Pb.The highest and lowest coefficient variation of the eight heavy metals was Hg and Cr,and the value was 0.40 and 0.10 respectively.A significant correlation was also observed between the eight heavy metals at 1% level.The C0 /（C ＋ C0） ratio of Ni and Cr was lower than 25% which indicated strong spatial dependence,while the other six heavy metals C0 /（C ＋ C0） ratios were between 25% and 75%,and had moderate spatial dependence.The range of heavy metal content varied from 25.99 km to 108.80 km,and the Cd had the largest range which indicated that Cd was correlated and depended on the soil parent material.Correspondingly,the Cr had the smallest range 25.99 km which implied that the length of the spatial autocorrelation was much longer than the sampling interval.The spatial distribution map showed similar geographical trends that western part was higher because there were more factories.The result showed that all the eight heavy metals were mainly affected by parent material,however human factors such as transport exhaust,chemical fertilizer and pesticides could not be neglected too.