Special vulnerability of ammonia-nitrogen in groundwater at drinking water source areas

The special vulnerability assessment is an effective means for quantitatively evaluating the groundwater contamination resulted from some special pollutants. Based on the hydrogeological analysis of the Qi Water Source Area in Jiamusi City, China, the DRASTIC model was selected to calculate the inherent vulnerability. The calculation mainly focused on investigating the impact of human factors, including different land use types, depression of the groundwater level in stable exploitation conditions, and the flux of the typical pollutant, i.e. ammonia nitrogen, in specific mediums. The special vulnerability of regional groundwater assessment index system was accordingly built and used for assessing the study area. The results has been verified by the correlation analysis between the observed concentration of ammonia from 28 shallow groundwater samples in the study area and the calculated special vulnerability at corresponding points,which indicate that the special vulnerability assessment system is reliable. The results show that the vulnerability of the regional groundwater is mostly at a moderate and low level, while the high level appears in the exploitation area and the southwest upland. This study is helpful for the scientific management of drinking water source areas.