Genesis of Hydrochemistry and Quality Evaluation of Shallow Groundwater Under Combined Anthropogenic and Geogenic Influences: A Case Study From Industrial Karst Area, Yuxi, China

ABSTRACT Shallow groundwater in karst area is closely linked to groundwater and surface water exchange. This is because recharge can be rapid and flow paths can be fast. These conditions can move solutes quickly and limit natural removal. As rainfall patterns change and human pressures increase, it becomes important to understand how hydrological forcing changes groundwater chemistry for water management. This study examines shallow groundwater in Yanhe Town, an industrially impacted karst area in Yuxi, southwest China. To evaluate seasonal effects, groundwater samples were collected in both the dry and wet seasons. Hydrochemical facies and controlling processes were investigated using Piper and Gibbs diagrams, correlation analysis, and Gaillardet end member modelling. Finally, two complementary methods were applied to assess water quality. Results indicate that the groundwater is weakly alkaline, with pH from 6.20 to 8.30. Calcium and bicarbonate dominated the chemistry. We identified seven hydrochemical facies, and bicarbonate calcium magnesium was the most common. Carbonate and silicate weathering provided the main natural ion source. Agricultural, industrial, and domestic inputs increased sodium and chloride. In addition, water quality results show persistent exceedances of manganese, iron, sulfide, and ammonia nitrogen. This pattern is consistent with diffuse inputs and redox related release. We also found acute hotspots. Cadmium at YZK2 exceeded the standard by 64.6 times, which suggests strong local industrial influence. Iodide at YZK1 exceeded by 4.78 times and was linked to a densely populated area. Seasonal comparison suggests that wet season recharge can lower peak values at some wells. It can also move contamination and expand the affected area through mobilization and transport. These findings support event aware monitoring and targeted mitigation in industrial karst settings. They also highlight a clear link between land use, recharge change, and groundwater and surface water vulnerability.