Source Apportionment and Ecological Risk Assessment of Heavy Metals in Sediments of Dongping Lake Based on PCA-PMF Model

Abstract Accurately characterizing the spatial distribution patterns of heavy metals in lake surface sediments, identifying their sources, and assessing potential ecological risks are critical scientific foundations for lake ecosystem management. This study selected Dongping Lake, a typical inland shallow lake in eastern China, as the research area. A comprehensive methodology was applied, integrating mathematical statistical analysis, cluster analysis, principal component analysis (PCA), and the Positive Matrix Factorization (PMF) model, combined with the enrichment factor method, geoaccumulation index method, and potential ecological risk assessment. This approach systematically investigated the distribution characteristics, source apportionment, and ecological risks of eight heavy metals (As, Zn, Cu, Ni, Cd, Hg, Pb, Cr) in the lake sediments. The results revealed an overall improving trend in heavy metal concentrations, with significant spatial heterogeneity—higher concentrations were observed in the central and southern regions. Multivariate statistical analysis identified three primary sources of heavy metal enrichment: industrial and agricultural activities (As, Cu, Hg, Cd), traffic emissions (Zn, Ni), and natural geological background (Cr, Pb). Enrichment characteristics indicated moderate to severe accumulation of Cd, As, and Hg. The potential ecological risk index (RI) highlighted Hg and Cd as the dominant risk contributors, accounting for 41.83% and 37.77% of the total risk, respectively. This study underscores the dominant role of anthropogenic activities in driving heavy metal accumulation in Dongping Lake sediments, providing a scientific basis for targeted pollution control and ecological restoration in the watershed.