Assessment of Soil Heavy Metal Pollution: Characteristics, Health Risks, and Source Apportionment in Shouguang City, China

Soil heavy metals (HM) are potential risk elements (PREs), evaluating soil pollution and risk levels is crucial for effective pollution control policies, contributing to sustainable development. In this investigation, 8806 surface soil samples from Shouguang City, Shandong Province, China, were systematically examined to assess the quality and source apportionment of PREs and conduct Human Health Risk Assessment (HHRA). Results indicate that the overall soil condition is generally clean and safe, showing a slight to moderate level of pollution. However, numerous outliers are present, with priority pollutants being Hg, Cd, Cr, and As. Polluted regions are mainly concentrated in areas with intense human activities. Principal Component Analysis (PCA) and Positive Matrix Factorization (PMF) models identified five pollution sources: urban activities (24.4%), traffic activities (23.8%), natural resources (22.1%), agricultural activities (16.4%), and metal smelting (13.4%). HHRA reveals notable risks exist for children, oral ingestion is identified as the primary exposure pathway, As and Cr emerge as major contributors. In this study, the PCA-PMF-HHRA model was used for the first time in the study of soil HM pollution in Shouguang City, providing important insights for the qualitative and quantitative analysis of regional soil HM pollution, and providing a basis for environmental protection and ecological restoration measures.