安徽典型硫铁矿集中开采区土壤重金属污染特征及来源解析

为查明安徽某典型硫铁矿集中开采区周边土壤重金属元素污染特征及污染来源，采集了研究区42个表层土壤样品和2个垂向剖面的16个土壤样品测定其pH值及Zn、Cu、Cd、Pb、Cr、Ni、Hg和As重金属元素含量，运用ArcGIS反距离权重插值法、内梅罗综合指数法、主成分分析法和绝对因子得分-多元线性回归（APCS-MLR）受体模型等方法进行了重金属元素分布特征分析、污染评价和来源解析.结果表明，土壤中8种重金属元素的含量平均值是铜陵地区背景值的1.03~13.14倍，Zn、Cu、Cd、Pb、Hg和As这6种重金属元素局部富集明显，在空间分布上与采矿活动位置基本一致.单因子污染指数评价显示，Zn、Cu、Cd、Pb和As这5种元素存在不同程度的污染风险，Cd和Cu元素污染程度最为严重，中度污染以上占比分别为47.62%和42.86%；内梅罗综合污染指数评价显示，研究区土壤样点中度污染以上占比为61.90%；地累积指数评价显示，研究区Zn、Cu、Cd、Pb、Hg和As这6种重金属元素污染程度主要为轻污染~强污染.在土壤剖面垂向变化上，重金属元素易在土壤表层富集，向深部迁移较缓慢，高含量主要在1 m以上位置.源解析表明，Zn、Pb和As的来源中地质高背景和采矿活动贡献率分别为37.82%、43.49%和46.63%，成土母质风化的自然来源贡献率分别为34.02%、40.88%和38.52%；Cr和Ni来源主要为成土母质风化的自然来源，贡献率分别为91.95%和73.68%；Cu的来源中地质高背景和采矿活动贡献率为41.91%，大气沉降和农业综合源贡献率为41.30%；Hg的来源较多，成土母质风化的自然来源贡献率为35.60%，地质高背景和采矿活动贡献率为29.87%，未知来源贡献率为34.05%；Cd的主要来源为大气沉降和农业综合源，贡献率为81.81%.

Pollution Characteristics and Sources of Heavy Metals in Soil of a Typical Pyrite Concentrated Mining Area in Anhui Province

To identify the characteristics and sources of heavy metal pollution in the surrounding soil of a typical pyrite concentrated mining area in Anhui Province, the pH value and the concentrations of Zn, Cu, Cd, Pb, Cr, Ni, Hg, and As in 42 surface soil samples and 16 soil samples from two vertical sections in the study area were collected and measured. The distribution characteristics, pollution assessment, and source analysis of heavy metal elements were conducted using the ArcGis inverse distance weight interpolation method, Nemero comprehensive index method, principal component analysis method, and absolute factor score-multiple linear regression (APCS-MLR) receptor model. The results showed that the average concentration of the eight heavy metals was 1.03-13.14 times the background value in the Tongling area. The local enrichment of Zn, Cu, Cd, Pb, Hg, and As was obvious, and the spatial distribution was basically consistent with the location of man-made mining activities. The single-factor pollution index evaluation showed that Zn, Cu, Cd, Pb, and As had different degrees of pollution risk, and the pollution degree of Cd and Cu was the most serious, accounting for 47.62% and 42.86% of moderate pollution, respectively. The Nemerow comprehensive pollution index evaluation showed that 61.90% of the soil samples in the study area were moderately polluted. The ground accumulation index evaluation showed that the pollution degree of Zn, Cu, Cd, Pb, Hg, and As in the study area was mainly from light pollution to strong pollution. In the vertical soil profile variation, heavy metals were easily enriched in the surface layer of the soil but migrated slowly to the deep layer, with concentrations mainly above 1 m. The results of source analysis showed that the high geological background and mining contribution rates of Zn, Pb, and As were 37.82%, 43.49%, and 46.63%, respectively. The natural contribution rates of weathering of parent material were 34.02%, 40.88%, and 38.52%, respectively. The sources of Cr and Ni were mainly natural sources of weathering of the parent material, with contribution rates of 91.95% and 73.68%, respectively. Geological high background and mining activities contributed 41.91% of the Cu sources, and atmospheric sedimentation and agricultural comprehensive sources contributed 41.30%. There were many sources of Hg. The natural source of weathering of soil parent material contributed 35.60%, geological high background and mining activities contributed 29.87%, and unknown sources contributed 34.05%. The main source of Cd was atmospheric sedimentation and agricultural comprehensive sources, contributing 81.81%.