干旱区生态环境知识资源中心

High contents of nitrogen in groundwater were found in the Turpan-Hami area, Xinjiang, China, whereas the enrichment characteristics and sources of nitrogen were poorly understood. In this study, totally 19 groups of groundwater samples were collected in the Turpan-Hami area for chemistry and isotope analysis. Combining with the hydrochemical, hydrogen, oxygen, and nitrogen stable isotopes data, the distribution and sources of nitrogen of groundwater in the Turpan-Hami area were analyzed. The results showed that the groundwater mainly originated from the atmospheric precipitation, and the evaporation was the dominant mode for groundwater discharge in Turpan-Hami area. The concentration of nitrate (NO (3) (-) -N) in groundwater varies from 23.29 to 1819.49 mg/L. Obvious enrichment trend of nitrogen was observed along the groundwater flow direction. The increase of nitrate, nitrite, and ammonia concentrations were consistent with that of TDS in the area. The concentrations of nitrogen species were dominated by the strong evaporation rather than human activity except for one sample. The delta N-15-NO (3) (-) in groundwater ranges from -0.6 to +31 aEuro degrees, and mostly in a range of +4.1 to +19.3 aEuro degrees. The delta O-18-NO3 (-) ranges from +16.3 to +37.4 aEuro degrees. The result indicated that nitrate in groundwater was mainly derived from atmospheric precipitation, and the conversion of nitrate, nitrite, and ammonia in groundwater was not active in the area.