Major ion chemistry of groundwaters in the Damagh area, Hamadan, western Iran

Hydrochemical investigations were carried out in Damagh area, Hamadan, western Iran, to assess chemical composition of groundwater. Forty representative groundwater samples were collected from different wells to monitor the water chemistry of various ions. Chemical analysis of the groundwater showed that the mean concentration of the cations is in the order Na+ > Ca2+ > Mg2+ > K+, while that for anions was HCO3- > Cl- > SO42- > NO3-. All of the investigated groundwaters present two different chemical facies (Ca-HCO3 and Na-HCO3) which is in relation with their interaction with the geological formations of the basin, cation exchange between groundwater and clay minerals and anthropogenic activities. The principal component analysis (PCA) performed on groundwater identified three principal components controlling their variability in groundwater. Electrical conductivity, Mg2+, Na+, SO42-, and Cl- content were associated in the same component (PC1) (salinity), determined principally by anthropogenic activities. The pH, CO32-, HCO3-, and Ca2+ (PC2) content were related to the geogenic factor. Finally, the NO3-, Cl- and K+ (PC3) were controlled by anthropogenic activity as a consequence of inorganic fertilizers.