HYDROCHEMISTRY OF THE GROUNDWATER IN SONGNEN PLAIN

The groundwater resources in Songnen Plain are significant for the local economic development. Based on the data from the new round of groundwater survey, the author studied the result of analysis on the quality of groundwater samples. It is concluded that, comparing those in 1980s, the chemical types and compositions of the groundwater in Songnen Plain have changed a lot. Agricultural pollution of the groundwater is quite serious. According to the National Quality Standard for Groundwater(GB/T14848-93), the ratio of samples that surpass the Grade IV standard of NO3-content in water is up to 26.9%, with 77.03 mg/L averagely;while the ratio for NO₂^- is up to 18.1%, with 0.14 mg/L averagely. In the main agriculture area, the NO₃^--type of water occurs, which was rarely seen in the result of the groundwater survey in 1980s.