Investigation of hydrochemical characteristics of groundwater in the Bukan basin, Northwest of Iran

Hydrochemical investigations were carried out in Bukan area, Northwestern Iran, to assess chemical composition of groundwater. A total of 35 groundwater samples were collected and analyzed for major cations and anions. The domination of cations and anions was in the order of Na+ > Ca2+ > Mg2+ > K+ for cations and HCO3 > SO4 2 > Cl in anions. The similarity between rock and groundwater chemistries in the recharge area indicates a significant rock-water interaction. The hydrochemical types Na + HCO3 + CL + Mg and Na + Cl are the predominate forms in the groundwater, followed by water Ca + Mg + SO4 + Cl and Ca + Mg + HCO3. Assessment of water samples according to exceeding the permissible limits prescribed by WHO for drinking purposes indicated that groundwater in study area is chemically suitable for drinking uses. The most dominant classes C2–S2, C2–S1 and C3–S2 were found in the studied area. The salinity hazard for water wells is classified as medium and high salinity.