Source Apportionment and Health Risk Assessment of Heavy Metals in Hongjiannao Lake Based on the APCS-MLR Model
To evaluate heavy metal contamination and human health risks in desert lakes, this study analyzed concentrations of seven heavy metals (Hg, Pb, Cu, Zn, Cd, Cr, As) in Hongjiannao Lake, Northern Shaanxi, from 2013 to 2024. The absolute principal component score-multiple linear regression (APCS-MLR) model quantitatively apportioned pollution sources, and a health risk assessment model evaluated non-carcinogenic and carcinogenic risks. Results showed average concentrations of the seven metals did not exceed background values, but 28.57% of sampling points exceeded background for As, with a maximum exceedance factor of 1.92. Total average concentration decreased from 112.51 μg/L (2013–2016) to 58.80 μg/L (2017–2024), attributed to the 2016 closure of small coal mines and ecological restoration around the 4A scenic area. Source apportionment identified four sources: industrial (35.44%), agricultural (24.67%), natural (23.65%), and traffic (16.23%), indicating industrial dominance. Non-carcinogenic risks were negligible, but carcinogenic risks exceeded the alert value (1×10⁻⁴), with adults at higher risk than children. Oral ingestion was the primary exposure pathway. As and Cd were key control elements, with exceedance rates of 100% and 16.67%, respectively. These findings provide a theoretical basis for health risk prevention and environmental management.