Hydrogeochemistry and Health Risk Assessment of Nitrate and Fluoride in Groundwater of Gorgan and Kordkuy, Iran

This study was conducted to assess hydrogeochemistry together with the non-carcinogenic health risk of nitrate and fluoride in groundwater of Gorgan and Kordkuy cities in the north of Alborz mountain belt. For this purpose, drinking water sources of these two cities were analyzed for hydrochemical characteristics including major ions, nitrate and fluoride. Results revealed that an increase in salinity of Kordkuy groundwater caused the various mixed and saline hydrochemical facies. Result of HFD and Gibbs diagrams revealed that rock-water interaction is chief contributing factor for release of ions into Gorgan groundwater. While, Kordkuy groundwater is more influenced by saline water that is originated from the subsurface layers. Human activities are the primary source of nitrate concentration in the Gorgan groundwater. In contrast, nitrate concentration of Kordkuy groundwater is more influenced by saline water. Results revealed that the hazard quotient (HQ) values of Gorgan drinking water samples for children are considerably higher than the permissible limit (HQ=1). In contrast, all HQ values of Kordkuy drinking water samples are below permissible limit and they don't cause adverse non-carcinogenic health risks for all age groups. Only three well in Kordkuy that their HQ of F- values are larger than the permissible limit for children. For the rest of drinking water samples, the HQ values of F- in both cities are less than permissible limit for all three groups.