Health Risk Assessment of Heavy Metals in Soil Around a Landfill Based on Monte Carlo Simulation
The accumulation of heavy metals in soil around municipal solid waste landfills poses potential risks to human health. This study selected a municipal solid waste landfill and monitored the concentrations of eight heavy metals (Zn, Pb, Cd, Ni, Hg, Cu, As, Cr) in surrounding soil. The geo-accumulation index method was used for pollution assessment, and a health risk assessment model recommended by the USEPA, combined with Monte Carlo uncertainty analysis, was employed to evaluate the pollution status and health risks to nearby residents. Results showed that among the eight metals, Pb, Ni, and Cd exceeded risk screening values at 4.26%, 6.38%, and 4.26% of sampling points, respectively. Geo-accumulation indices indicated overall clean conditions (mean < 0), but slight pollution by Pb, Zn, Ni, Hg, and Cd at some points. Probabilistic risk assessment based on Monte Carlo simulation revealed that for both adults and children, the cumulative non-carcinogenic risk was negligible, while carcinogenic risk was acceptable. However, there was a very low probability (approximately 0.2%) of non-carcinogenic risk for children, and probabilities of unacceptable carcinogenic risk were 0.64% for adults and 3.21% for children. Nickel was the primary contributor to carcinogenic risk, and children faced higher health risks than adults. These findings provide a reference for pollution prevention and health risk management of soil around municipal solid waste landfills.