关键词: 锰矿区　土壤重金属　污染特征　APCS-MLR 模型

Abstract: Due to long-term mining activities,the agricultural land in the surrounding area of a typical manganese mining
concentration zone in northern Guizhou has been affected by varying degrees of heavy metal pollution. To provide scientific support
for subsequent ecological restoration and environmental management,this study collected 362 surface soil samples from the
agricultural land system around more than ten manganese mines and over twenty abandoned mine slag heaps in the area. Based
on the determination of the contents of heavy metals such as Mn,Hg,Cd,As,Cr,Cu,Ni,Pb,and Zn,the pollution degree was
evaluated using the geoaccumulation index method and the improved Nemerow pollution index method. Combined with correlation
analysis,cluster analysis,the absolute principal component score-multiple linear regression (APCS-MLR) model,and spatial
analysis methods,the pollution characteristics and sources of heavy metals in the soil were comprehensively analyzed. The
results showed that the average contents of the nine heavy metals in the study area were all higher than the background values
of Guizhou Province′s soil,indicating a certain degree of enrichment. Among them,the spatial distribution of Mn,Cd,Cr,Cu,
Ni,and Zn was highly consistent with the slag heap distribution area,and their high concentration areas were mainly concentrated
near the slag heap range,indicating that their enrichment was mainly affected by mining activities. However,the spatial patterns
of Hg,As,and Pb deviated from the slag distribution characteristics and showed distribution trends related to human-dom-inated processes such as agricultural activities and transportation,reflecting the significant role of non-mining source inputs.
The source analysis results showed that the heavy metals in the soil mainly originated from three types of pollution sources:
mining activity emissions,agricultural activities and transportation emissions,and composite pollution sources,with contribution
rates of 40. 23%,30. 57%,and 29. 20%,respectively. Specifically,Ni,Cr,Cu,Mn,Zn,and Cd mainly originated from mining
activities;Among them,Cu was also affected by the parent material of soil formation to a certain extent,and Mn and Cr may
partially originate from agricultural activities and geological background. The source of Cd was more complex,with contributions
from agricultural activities,transportation,and parent material of soil formation to varying degrees. Zn was also affected by the
superimposition of transportation and parent material of soil formation. Hg,As,and Pb were mainly derived from transportation
activities,while As and Pb were also significantly input by agricultural activities,demonstrating the characteristics of multipathway
composite input.

Key words: manganese mining area,soil heavy metals,pollution characteristics,APCS-MLR model