# Groundwater Driving Factors Identification and Its Associated Human Health Risk Assessment in a Metropolitan City of Southwest China

## TL;DR

This study identifies factors affecting groundwater quality in Chongqing and assesses health risks, especially for children.

## Contribution

The study introduces a reliable health risk assessment method using KDE-based Monte Carlo simulation.

## Key findings

- The main groundwater facies is Ca–HCO3, influenced by silicate weathering and human activities.
- Nitrate and nitrite levels pose noncarcinogenic health risks to children in certain areas.
- The KDE-based Monte Carlo method proved reliable for health risk assessment.

## Abstract

Health risks associated with groundwater deterioration have become increasingly prominent worldwide. Accurate assessment of human health risks associated with groundwater is a critical component of groundwater development and utilization, particularly in large metropolitan areas with high water resource demands. In our study, 37 groundwater samples were collected from the main urban areas of Chongqing, the largest city in southwest China, to identify the groundwater driving factors and their associated human health risk. The primary hydrochemical facies in the study area is Ca–HCO3. Groundwater hydrochemistry is primarily controlled by silicate weathering, carbonate (dolomite and calcite) dissolution, and anthropogenic activities such as industrial and agricultural activities. The hazard index (HI) caused by NO3− and NO2− was higher than the safety standard and exhibited potentially noncarcinogenic risk for children in the north and the west of the study area. The KDE-based Monte Carlo simulation method showed a high reliability in human health risk assessment, with all mean values of the original dataset falling within their corresponding 95% confidence intervals (CIs) of generated data. The achievement can provide valuable insights for groundwater risk mitigation and resource management in Chongqing’s main urban areas, as well as in other metropolitan regions worldwide.