Soil Heavy Metal Pollution in Upstream Bailang River, Eastern China: Spatial Analysis, Health Risks, and Pollution Source Identification

The ecological and environmental concerns within Shandong Province's Bailang River basin in eastern China have garnered significant research attention. This study specifically delves into the issue of soil heavy metals (HM) pollution in the upstream area of the Bailang River. Diverse methodologies were employed to quantitatively assess the pollution status, ecological implications, and associated health risks posed by HM. Geostatistical methods facilitated a spatial analysis of soil variations, while Principal Component Analysis (PCA) was utilized to attribute the sources of soil pollutants. The study area was found to be at a moderate level of pollution, with Cd (Coefficient of Variation, CV = 37%), Ni (CV = 49%), and Hg (CV = 69%) identified as primary pollutants in both quantitative analyses and ecological risk assessments. Overall, the concentration of HM was higher in the western area than in the eastern zone, suggesting a moderate pollution level within the central study zone. Human health risk evaluations indicated that non-carcinogenic risks (Total Hazard Index – THI) for adults and children met acceptable thresholds (0.11 and 0.98). However, 57.14% of children faced unacceptable non-carcinogenic risks, primarily attributed to Chromium (Cr) and Arsenic (As) exposure. Carcinogenic risks (Total Carcinogenic Risk Index – TCRI) for children indicated an unacceptable level of risk. Oral intake was the primary method of absorption. Qualitative analysis (PCA) identified major pollution sources, including natural emissions and traffic, coal combustion, agricultural activities, and iron and steel production. This study provides valuable insights for environmental safeguarding and the comprehensive evaluation of soil HM pollution.