Analysis of the Factors Influencing Nitrate Nitrogen Concentration Using Structural Equation Modeling: Integrating Natural Environmental and Hydrological Factors.

Identifying and quantifying the factors influencing nitrate-nitrogen concentration is essential for controlling groundwater pollution and performing source apportionment. This study aimed to analyze the driving forces of nitrate-nitrogen contamination by integrating correlation analysis and structural equation modeling (SEM). The results indicated that the study area was affected by multiple combined factors, primarily agricultural activities, fecal contamination, and domestic sewage, while industrial sources also contributed to nitrate-nitrogen levels. Different land use types exert varying influences on nitrate concentrations. Both precipitation (PRCP) and groundwater table depth (DTW) negatively correlated with nitrate-nitrogen concentration. Nitrate-nitrogen was also correlated with sulfate, chloride, strontium, copper, fluoride, and hexavalent chromium. The relative influence of different factors on nitrate-nitrogen concentration followed the order: cultivated land > construction land > sulfate > DTW > strontium > PRCP > hexavalent chromium > fluoride > copper > grassland > water area > chloride. By integrating natural environmental and hydrological factors, and applying correlation analysis and SEM, the study effectively identified and visualized the complex interactions among influencing variables. These findings provide valuable insights for nitrate pollution control in groundwater within the Hutuo River alluvial-pluvial fan region.