An Assessment of Factors Affecting the Geochemistry of Ghaemshahr Coastal Aquifer using Factor Analysis

In order to identify control processes and determine the origin of ions in groundwater, sampling has been conducted from 22 wells in operation related to the average of two periods in 1999 and 2011. In this sampling, 13 parameters, including main anions and cations with pH, TDS, EC, hardness and alkalinity, have been tested. In this study, to determine saturation indices and factor analysis, SPSS and Phreeqc software have been employed, respectively. In this aquifer, calsic and sodic bicarbonate and sodium chloride water types are dominant. Saturation indices play an important role in both periods in dissolution, sedimentation and ion exchange. Factor analysis results indicated that in 1999, four factors with 96% and in 2011, and two factors with 87% control changes in groundwater quality. These factors are divided into two categories: natural and unnatural. Natural factors are related to weathering and water-rock interaction, leakage and saltwater intrusion. Non-natural processes are concerned with human activities including wastewater of various chemical fertilizers, excessive withdrawals, evaporation and industrial wastewater. Owing to the lack of wastewater collection system and disposal of municipal and industrial wastewater through absorb wells have caused the increase in sulfate ions, in most parts, to have non-natural origin, calcium and magnesium, both natural and non-natural origin and sodium chloride have natural origin.

Ghaemshahr Plain, Factor Analysis, Principal Component Analysis, Saturation Indices, Human Activities.