The Determination of Effective Factors on Groundwater Quality Using Graphical and Multivariate Statistical Methods

In order to determine the effective factors in groundwater quality of Bandar Gaz water sources were tested graphical and multivariate statistical methods, the related data of seven well was used. The groundwater sources were seen differently according to Stiff and Drouv diagrams. The drawn composite plots were shown the linear procedure between Na+ and Cl-, due to mixture of saltwater and soft water. Dolomite saturated index(SId) was more than calcite saturated index(SIc), because the dolomite dissolve in direction of groundwater flow. According to correlation matrix, other ions (except SO42- and NO3-)were correlated respect with electrical conductivity. Cl- has more combination with Na+ and K+. The cluster diagrams show that there are similarity between Cl- -Na+ ions and Cl- -K+ in groundwater more than 95%, and 85%. With respect to cluster diagrams, the dominated type of groundwater was Ca-SO4-HCO3. According to the analysis method; five factors were effective on chemical combination of groundwater. First factor: intrusion of salt water because the Na+, K+ and Cl- ions have high factor loading. Second factor: Human activities (seepage of wastewater, absorbing wells and…), because nitrate had the highest load in third factor. The nitrate concentration in groundwater was influenced by wastewater and irrigation of agriculture fertilizers. Third factor: Aquifer hydrogeochemical process, because factor loading of Ca2+ and Mg2+ was decreased and Na+ was increased. Fourth factor: Feeding by surface water (river, runoff…) because of HCo3- and Na+ increment. Fifth factor: Dolomite solution caused to increase of Mg2+ factor loading.