Analysis of Heavy Metal Sources in Shallow Groundwater and Human Health Risk Assessment in Long'an District, Anyang...

The issue of heavy metal contamination in groundwater has garnered increasing attention. To investigate the distribution characteristics of heavy metals, potential pollution sources, and associated human health risks in shallow groundwater within Long'an District, Anyang City, China, a total of 57 groundwater samples were collected for testing and analysis. Employing multivariate statistical analysis methods and Monte Carlo simulation, this study elucidated the sources and human health risk levels of seven heavy metals present in the groundwater: arsenic (As), cadmium (Cd), chromium (Cr), manganese (Mn), iron (Fe), lead (Pb), and mercury (Hg). According to the HPI index-based pollution assessment results, moderately polluted sites accounted for 31.58%, with As, Hg, and Cd being the primary impact indicators. The detection rates for the remaining indicators-Cr, Mn, Fe, and Pb-were relatively low, indicating a lesser impact on water quality. The most prominent heavy metal contamination was observed in the fracture-pore water in clastic rocks in the southwestern region, with human industrial and agricultural activities identified as the key contributing factors. Principal component analysis identified Pb and Cd as the primary heavy metal sources (first principal component), representing industrial wastewater and exhaust emissions with strong representativeness. The second principal component (Fe and Mn) demonstrated poor representativeness, while the third component (Hg and As) constituted the primary indicators affecting groundwater quality in the study area, originating from natural geological sources. The current health risk level for shallow groundwater is generally acceptable. Monte Carlo simulation results indicate that noncarcinogenic risks are all within acceptable limits, whereas carcinogenic risk values present unacceptable levels. Among heavy metals, As poses the greatest health risk, followed by Cd. The primary exposure pathway is daily drinking water consumption. As and Cd are the heavy metal elements requiring the most attention in groundwater environmental protection efforts.