Potential Impacts of Wildfires on Regional Water Quality: A Case Study of the “8·19” Forest Wildfire in Jiangjin, Chongqing

This study examines the impacts of forest wildfires on water quality using the Chongqing August 19, 2022 forest wildfire as a representative case. By integrating water quality, meteorological, and atmospheric pollutant (black carbon and organic matter) data sets, we employ spatial statistical analysis, HYSPLIT airflow trajectory modeling, and the Potential Source Contribution Function (PSCF) model to investigate regional water quality variations before and after the wildfire event. The results reveal significant water quality degradation during August-September 2022, manifested by Total nitrogen concentrations surging to 3.33 mg/L in some areas, turbidity peaking at 111.7 NTU, and a marked reduction in surface water supplies classified as class III or higher. PSCF analysis shows consistent patterns between the north–northwest pollutant transport direction, elevated BC/OM levels, and water quality impairment zones. Our findings highlight both direct deposition effects from wildfire pollutant and indirect atmospheric pollution pathways. This research underscores the urgent need for integrated watershed management strategies that account for both direct and secondary wildfire impacts in the context of ongoing climate change.