Health Risk Assessment of Heavy Metals in Soil of Lalu Wetland Based on Monte Carlo Simulation and ACPS-MLR

Abstract

Lalu wetland is the world’s largest plateau urban wetland. It was designated as a national-level nature reserve in China in 2004 and is often called “the lung of Lhasa”. It serves as a vital recreational area for urban residents. Concerns have arisen about the potential harm to human health due to heavy metals (HMs) in the wetland soil. This study assessed the ecological risk of HMs in Lalu wetland soil by using the potential ecological risk index and geo-accumulation index techniques. The findings showed that the Lalu wetland’s overall risk level is low risk. with Cd being the primary pollutant. Through the absolute principal component scores–multiple linear regression (APCS-MLR) model and Pearson correlation analysis, three sources of HMs were identified, including traffic sources, soil parent material sources, and geothermal sources, contributing 51.13%, 32.35%, and 16.52%, respectively. The results of the probabilistic health risk assessment based on Monte Carlo simulation indicate that non-carcinogenic risks are absent for both adults and children. However, acceptable carcinogenic risks are present. For adults, the main exposure mode is through dermal contact, while children are primarily exposed through ingestion. Children manifest a heightened vulnerability to these risks compared to adults, with As being the primary contributing element. The source-oriented health risk assessment (HRA) highlights geothermal sources as the primary contributors to health risks. The research results provide insights into the current status of HMs in Lalu wetland soil, offering a scientific basis for restricting and managing contamination by HMs in wetlands.