Migration mechanism of groundwater pollutants in industrial parks based on the Yangtze River protection and groundwater vulnerability assessment

The contamination of groundwater systems by industrial activities represents a pervasive global issue threatening water quality and safety. This study investigated the hydrogeological characteristics of the chemical park along the Yangtze River, by employing MODFLOW and MT3DMS to construct numerical models for groundwater flow and solute transport; the migration path and spatial extents of representative contaminants [ammonia nitrogen (NH3–N), manganese (Mn), 1,2-dichloroethane, and volatile phenols] were analyzed. The multi-year results indicated that after 20 years, the contaminant extent in the study area was further expanded. Under natural rainfall scenarios, the area of the contaminant plume increased by 88.55–249.38% compared to the initial state, while under heavy rainfall scenarios, the increase ranged from 72.03 to 222.62%. Contaminants migrated with groundwater flow to the Yangtze River coast and Huangmaotan River, with a faster migration rate observed during heavy rainfall scenarios. It is necessary to implement source treatment and pollution control at surface water boundaries to ensure the safety of the Yangtze River water quality. This method can also be used to assess the potential pollution of similar projects along the Yangtze River and aid decision makers and managers.