Investigation of Groundwater Quality Using Multivariate Statistical Methods in Ardabil Plain Aquifer

Pollution and declining quality of water resources reduce usable water resources, weaken economic development and threaten human health. In this study, groundwater quality was studied and analyzed in Ardabil aquifer. For this purpose, 32 samples of groundwater sources in the Ardabil plain were collected and the concentrations of major ions, minor ions and some heavy metals were measured. Then, hydrogeochemical factors affecting the groundwater quality of the study area were analyzed using multivariate statistical methods, including correlation coefficients and factor analysis. According to the correlation matrix, the concentrations of metals such as arsenic, barium, scandium, silicon, zinc and vanadium indicated a little correlation with the main ions. Therefore, it can be concluded that the entry of these elements into groundwater is due to human activities. In factor analysis, the groundwater quality changes were affected by four main factors with 77.31% of the total variance of data in Ardabil plain. The results of factor analysis showed that the first factor was lithogenic, the second and third factors were lithogenic and anthropogenic, and the fourth factor was just anthropogenic. The results showed that the concentrations of heavy metals such as arsenic, barium, scandium, silicon, vanadium and zinc did not have a high correlation with the main ions, so the presence of these elements could be due to human activity. Also, the greatest effect on groundwater hydrochemistry in the study area was related to magnesium, sodium, calcium ions and electrical conductivity.