广东省土壤重金属溯源及污染源解析

近年来土壤重金属污染问题日益加剧,而土壤重金属溯源解析对土壤重金属污染防治具有重要的指导意义.本文采集并测试了广东省土壤表层(0~20 cm)1000个样本中的As、Cd、Cr、Cu、Hg、Ni、Pb和Zn 8种重金属元素的含量,选取了可能影响这些重金属元素在土壤中含量的106个因子,将其分为自然和人为两大类,基于回归模型树方法,通过R语言及Cubist模型定量计算这些影响因子对8种重金属元素在土壤中含量的贡献率,筛选不同元素的主要影响因子,进行溯源及污染源解析.结果表明:广东省土壤中As、Cd、Cr、Cu、Ni、Pb和Zn来源受自然因素作用大于人为因素,土壤中Hg则相反,其主要来源于工业生产,部分来源于农业生产.土壤中Cd和Hg元素的人为源具有同源性.广东省土壤重金属人为源贡献率由大到小分别为土壤As为工业农业交通人口其他;Cd为工业农业交通其他;Cr为农业工业交通、人口其他;Cu为工业农业交通其他;Hg为工业农业交通、矿区人口建筑;Ni为工业农业交通其他;Pb为工业农业其他;Zn为工业农业人口其他.本研究结果有利于指导相关产业减少污染排放,降低土壤环境质量受到的污染风险.

Source apportionment analysis of trace metal contamination in soils of Guangdong province, China

Soil contamination with heavy metals has become a severe problem in China. In order to prevent and control heavy metal contamination in soils, it is essential to understand the pollutant source. Based on the concentration data of eight trace metals (i.e. As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) for 1000 soil samples from the surface layer (0~20 cm) of Guangdong Province and 106 explanatory factors categorized into two groups of natural and anthropogenic factors, using R and Cubist model, this study identified the dominant influencing factors of soil contamination by calculating the relative contributions of two or more sets of explanatory factors in explaining the variation of soil contamination. The results showed that among the eight heavy metals of Guangdong Province, As, Cd, Cr, Cu, Ni, Pb and Zn were mainly natural origin, whereas Hg was mainly anthropogenic origin mostly derived from industrial activities and partly from agricultural activities. The anthropogenic source of Cd was consistent with that of Hg. The contributions of different anthropogenic sources of soil contamination from high to low were in the order of industrialization > agriculture > transportation > population > others for As, industrialization > agriculture > transportation > others for Cd, agriculture > industrialization > transportation and population > others for Cr, industrialization > agriculture > transportation > others for Cu, industrialization > agriculture > transportation and mining activities > constructions for Hg, industrialization > agriculture > transportation > others for Ni, industrialization > agriculture > others for Pb, and industrialization > agriculture > population > others for Zn. Our findings provide guidance in reducing pollutant emissions and preventing soil contamination.