北京东南郊土壤重金属元素分布及其在表层土壤中的富集特征

通过采集并分析北京东南郊地区表层(0~20 cm)和深层(160~200 cm)土壤样品的重金属元素,查明该地区土壤中元素分布特征,并通过建立半变异函数模型探讨重金属元素的空间自相关性,利用富集系数探讨元素在表层土壤中的富集特征,在此基础上划分出重金属元素显著富集区,并对富集原因进行了深入解释和分析。结果表明:研究区表层土壤Cd、Cu、Hg、Pb、Zn总体含量水平明显高于深层,差距在1.2~3.9倍不等;与北京地区和中国地区土壤重金属元素含量相比,研究区土壤中相对富集Cd、Hg。受成土母质来源差异性和人类活动等诸多因素的影响,表层土壤As、Cr空间自相关性较强,深层土壤Cr空间自相关性较弱,表层和深层其他元素空间自相关性中等。As、Ni、Cr在表层土壤中的富集程度较弱,而Cu、Pb、Zn、Cd、Hg富集程度较强,富集程度最强的是Hg。以富集系数作为参考依据,圈定出5处重金属元素的显著富集区域,清晰地反映了人类生活、农业种植、工业生产等均是造成重金属元素在表层土壤中富集的重要影响因素;因此,需要密切关注人类居住区、农业种植区、工业企业分布区的土壤元素分布状况,以防止土壤环境恶化和保障生态环境安全。

Distribution of heavy metal elements in soil of the Southeastern suburbs of Beijing and their enrichment characteristics in surface soil

By collecting and analyzing the heavy metal elements insurface (0~20 cm) and deep (160~200 cm) soil samples in southeastern suburbs of Beijing, the distribution characteristics of elements in soil in this area were ascertained.The spatial autonomy of heavy metal elementswas explored by establishing a semivariogram model. The enrichment characteristics of elements in surface soil were discussed,as well as the correlation of the enrichment coefficient. On this basis of the research, the significant enrichment areas of heavy metal elements are divided, and the reasons for the enrichment are explained and analyzed in depth.The results show that:The content levels of Cd, Cu, Hg, Pb, and Zn in surface soil of the study area are significantly higher than those in the deep layer, with a gap of 1.2 to 3.9 times. Compared with soil’s heavy metal content in Beijing and China,, the soils in the study area is relatively rich in Cd and Hg. As it was affected by many factors such as the source of soil-forming parent material and human activities, the spatial autocorrelation of As and Cr in surface soil is strong, and the spatial autocorrelation of Cr in the deep soil is weak. The spatial autocorrelation of other elements in the surface and deep layers is medium. As, Ni, and Cr in the surface soil are weakly enriched.But Cu, Pb, Zn, Cd, Hg are strongly enriched, and Hg is the most enriched. Based on the enrichment coefficient, five significant enrichment areas of heavy metal elements are delineated.The division of this area clearly reflects that human life, agricultural planting, and industrial production are important factors that cause the accumulation of heavy metal elements in surface soil.Therefore, it is necessary to pay close attention to the distribution of soil elements in human settlements, agricultural planting areas, and industrial enterprise distribution areas. The purpose is to prevent the deterioration of the soil environment and ensure the safety of the ecological environment.