Hydrogeochemical evaluation of groundwater in the north of Qazvin Plain

Groundwater has become the most important natural resource in recent years due to lack of rainfall and less surface water. In this Study, the effect of geological and agricultural activities on groundwater resource area in north of Qazvin Plain has been studied. For this research to study the qualitative parameters, 17 wells were sampled in 2013. Initially for estimation of the impact of geology on groundwater samples, water type and saturation index (SI) of various minerals were studied, then the impact of human factors on groundwater resources in the North of Qazvin plain was investigated by using linear regression analysis. Results showed that the amount of dissolved minerals from the west to the east of the study area is on the rise. Ions of sodium, bicarbonate and sulfate are dominant ions, mostly as a result of the dissolution of halite, gypsum and carbonate which entered the groundwater. Linear regression analysis showed that high correlation of nitrate, sulfate, chloride, potassium, and total dissolved solids (TDS) reflects the impact of agricultural activities on groundwater. Nitrate concentration was found to be much higher than WHO 2011 standards (50 ppm) in western (335 ppm) and eastern (103 ppm) parts of study area as a result of agricultural activities.