东洞庭湖土壤重金属污染空间分布

Spatial Distribution of Soil Heavy Metal Pollution in East Dongting Lake

摘要: 本研究系统评估了中国湖南省东洞庭湖区域表层土壤中六种重金属元素(As、Hg、Cd、Pb、Ni、Cr)的污染特征及其生态风险。研究采用多元方法学框架，包括单项污染指数(P)、地累积指数(Igeo)和潜在生态风险指数(Er)进行污染程度评估；运用Moran’s I指数分析重金属空间自相关特征；并通过对比四种空间插值方法的精度，确定了最优的空间分布表征方法。污染源解析采用绝对主成分得分–多元线性回归(APCS-MLR)和正矩阵分解(PMF)受体模型。研究结果表明，研究区域呈现显著的Cd和As重度污染，Hg、Pb、Ni次之，Cr为轻度污染。源解析显示主要污染源包括农业活动(贡献率最高)、工业排放和人为活动。空间分析表明耕地和牧地分布与重金属浓度呈现显著的空间一致性。基于研究结果，建议相关部门在农业生产过程中采取针对性措施，以降低土壤重金属污染及其潜在生态风险。

Abstract: This study systematically assessed the pollution characteristics and ecological risks of six heavy metal elements (As, Hg, Cd, Pb, Ni, Cr) in the surface soils of the Dongting Lake area in Hunan Province, China. A multi-methodological framework, including individual pollution index (P), geoaccumulation index (Igeo) and potential ecological risk Index (Er), was used to assess pollution degree. Moran’s I index was used to analyze the spatial autocorrelation characteristics of heavy metals. By comparing the accuracy of four spatial interpolation methods, the optimal spatial distribution characterization method is determined. The absolute principal component score-multiple linear regression (APCS-MLR) and positive matrix decomposition (PMF) receptor models were used for source analysis. The results showed that Cd and As were heavily polluted in the study area, followed by Hg, Pb and Ni, and Cr was slightly polluted. Source analysis shows that the major sources of pollution include agricultural activities (which contribute the most), industrial emissions, and anthropogenic activities. The spatial analysis showed that the distribution of cultivated land and grazing land was significantly consistent with the concentration of heavy metals. Based on the research results, it is suggested that relevant departments should take targeted measures in the agricultural production process to reduce soil heavy metal pollution and its potential ecological risks.