Characteristics of nitrogen pollution for shallow groundwater in typical urban planning area in Taihu Lake Basin

Abstract

In order to verify the nitrogen pollution status of shallow groundwater in typical city of Taihu Lake Basin, urban planning area of Suzhou city was selected as the study area, and 14 sampling sites representing different land use types were selected to carry out water quality analysis. The status, temporal variability of nitrogen pollution and composition characteristics of various forms of nitrogen for shallow groundwater were analyzed. The results show that the nitrogen pollution of shallow groundwater in study area is relatively serious. The average contents of total nitrogen, dissolved inorganic nitrogen, total organic nitrogen, ammonia nitrogen, nitrite nitrogen and nitrate nitrogen are 8.23, 5.45, 2.77, 2.53, 0.12 and 2.81 mg/L, respectively. The variation coefficients of various forms of nitrogen are large and the spatial differentiation is significant. The contents of ammonia, nitrite and nitrate in shallow groundwater show an obvious spatial distribution characteristics. Nitrogen pollution in old urban areas is much more serious than other types of areas, especially ammonia nitrogen pollution is particularly prominent. Inorganic nitrogen is the main form of nitrogen in groundwater, while ammonia nitrogen is the main form of inorganic nitrogen.