EVOLUTION OF URBAN GROUNDWATER QUALITY UNDER HUMAN DISTURBANCE IN HARBIN, CHINA: IRON AS AN INDICATOR

Groundwater with an inherently high iron concentration is widely distributed in the quaternary system of sand and gravel aquifers in Harbin. This study reveals that groundwater quality in Harbin in relation to iron concentration distribution has changed with human activities in the last 20 years. Using the recorded data of groundwater table and hydrochemistry over the last 20 years from 80 wells, groundwater quality analysis was conducted and relationships between the groundwater iron concentration and exploitation intensity, pH value of precipitation water, fertilizer used on farm land, and the discharge of sewage were discussed. The results show a positively strong correlation between iron concentration in the groundwater and human activities. Variations in the dynamic curve of the groundwater iron concentration also reflect the above phenomenon. On the other hand, the study reveals the spatial distribution of iron concentration to be related with the groundwater drawdown funnels. However, the formation of the drawdown funnel was noted to precede the occurrence of high iron concentration area.