城市生活垃圾焚烧是重金属的重要人为排放源.为研究垃圾焚烧厂周围土壤重金属的浓度水平与空间分布,利用多元统计方法分析了深圳市清水河垃圾焚烧厂周围80个典型土壤样品中Hg、As、Cd、Cr、Cu、Ni、Pb、Se、Zn共9种重金属浓度.参照自然背景,该垃圾焚烧厂周围土壤上述重金属浓度分别为0.012~0.136、0.23~75.89、ND~1.17、21.7~116.0、ND~61.1、ND~47.0、ND~133.0、ND~16.4、8.6~246.9mg·kg^-1(ND为未检出),未发现明显高累积现象.聚类分析与历史比较表明,土壤中重金属的空间相关性发生改变,根据相似性可分为3类:①cu、Ni、Cr、Se、Zn、Pb;②As、Cd;③Hg,成因与垃圾焚烧源相关.因子分析结果表明,3类金属在该垃圾焚烧厂周边区域具有不同的空间分布格局特征,分别以土壤生物地球化学作用(48.6%方差贡献)、垃圾焚烧源(16.6%)、地形地貌特征(13.2%)3个因子为主导影响因素,并据此绘制得对应因子得分地图.本研究为评估垃圾焚烧厂重金属排放对周边土壤的长期影响并进行缝康风险评价提供依据.
The municipal solid waste (MSW) incineration has been well known among key sources of heavy metal (HM) emission. To investigate the multivariate relationships and spatial distribution of HMs from this source, 9 HMs (Hg, As, Cd, Cr, Cu, Ni, Pb, Se and Zn) were analysed by multivariate statistical analysis in 80 representative soil samples including surface soils and subsurface soils around the Shenzhen Qingshuihe MSW Incineration Plant (MSWIP). Results show that, the concentrations of Hg, As, Cd, Cr, Cu, Ni, Pb, Se and Zn range 0. 012-0. 136, 0. 23-75.89, not detected (ND)-1. 17, 21.7-116.0, ND-61. 1, ND-47.0, ND-133. 0, ND- 16.4 and 8.6-246.9 mg. kg^-1 , respectively. No significant elevation of concentrations of HMs in soils is observed, compared with the natural background. Based on the hierarchical cluster and historical analysis, the spatial correlations of HMs have been changed by the impact of MSWIP. According to the similarity of concentration, the HMs can be divided into 3 categories : (1)Cu, Ni, Cr, Se, Zn, Pb; (2)As, Cd; (3)Hg. Factors analysis was also performed and shows that the HM distribution patterns are dominantly affected by 3 principal components: local biogeochemical characteristics (48.6% of variance) , impact of the MSWIP ( 16. 6% of variance) as well as topographical characteristics (13.2% of variance). Subsequently the 3 maps of factor scores are calculated and exhibited. This study favors to estimate the long-term effects of HM emission from MSWIP on surrounding soil environment and facilitate the local health risk assessment.