Groundwater salinity and quality assessment using multivariate statistical and hydrogeochemical analysis along the Urmia Lake coastal in Azarshahr plain, North West of Iran

Abstract

In the present study, the aim was to investigate groundwater quality and salinity in one of the highly affected areas along the hyper-saline Urmia Lake. Accordingly, physicochemical parameters from 77 groundwater wells were assessed using multivariate statistics and hydrogeochemical analysis in case of groundwater salinity and quality of Azarshahr plain. Based on the electric conductivity of the water, the results show that almost 41% of the wells are freshwater (< 1000 µS/cm), 18% slightly saline water (1000–3000 µS/cm), and 42% moderately saline water (3000–10,000 µS/cm). Based on Gibbs plot, rock weathering was a dominant process in the plain so that about 80.7% of the samples fall under very hard class. Results from Principle Component Analysis and Hierarchical Cluster Analysis divided the groundwater into four distinct zones: cluster 1 in the western area of the plain is known as recharge zone (Ca–HCO3 water type), cluster 2 northwest of the study area is influenced by saline water up-coning during agriculture pumping (Ca–Cl water type), cluster 3 north of the study area is affected by rock weathering (Ca–HCO3–Cl water type), and finally cluster 4 in the central plain is mostly influenced by wastewater and agricultural fertilizers (Ca–SO4–Cl water type). It was also found that there are high concentrations of TDS, Cl−, and SO42− in the agricultural areas which was also showing an increasing trend within 2010–2014. Finally, it was found that agricultural activity, contamination and salinization from irrigation, use of fertilities, and up-coning salt water during pumping are among the factors in deterioration of groundwater resources in the studied area.