Effects of groundwater level variations on the nitrate content of groundwater: a case study in Luoyang area, China

Abstract

Most researchers usually adopt laboratory experimental methods when studying the effects of water level variations on the concentrations of pollutants. In this study, the data from routine monitoring sites in the city of Luoyang, China, are collected and analyzed to verify the results of previous laboratory experiments and to examine whether variations in the water level affect the concentration of pollutants in different locations, particularly that of nitrates. Statistical studies conducted between 2007 and 2011 show a significant variation in the groundwater depth in the Luoyang area. This depth variation clearly affected the groundwater environment in the soil system. This study uses field data to investigate the effects of water table fluctuation on the nitrate content of groundwater. Hydrogeological information and land management data are collected from five monitoring points in Luoyang. The significance of and correlation between the environmental indicators of groundwater depth and soil–water systems are then analyzed using SPSS and Origin software. The results show that the redox potential (Eh) and nitrate nitrogen content are strongly correlated with groundwater depth. Significantly negative correlations were found between nitrate nitrogen and ammonium nitrogen concentration, between Ehand ammonium nitrogen concentration, and between pH and nitrate nitrogen concentration. These results indicate that water table fluctuation affects the soil–water physicochemical properties and further exerts a significant effect on nitrate movement across soil sola.