Assessment of Khibiny Alkaline Massif groundwater quality using statistical methods and water quality index

Groundwater is a major source for the water supply of households in the mining-intensive area of Khibiny Alkaline Massif, Kola Peninsula, in the Arctic. There are an increasing number of signs of groundwater quality deterioration in the area caused by the presence of elevated aluminum concentrations. Groundwater quality studies using univariate and multivariate statistical methods and the Water Quality Index were conducted to analyze a field dataset including 12 groundwater quality parameters monitored between 1999 and 2012. Descriptive statistics showed that the monitored water did not meet the established drinking water standards for aluminum concentration and pH level. The calculated Spearman correlation coefficient matrix revealed statistically significant associations (alpha-level = .05) between Al concentrations and pH values, concentrations of SO42-, NO3-, Cl-, and TDS. Factor analysis using the principal component analysis extraction method (FA/PCA) identified four major influencing factors. Altogether the factors captured 67.53% of the dataset total variance. The outcomes of the hierarchical cluster analysis (HCA) revealed that the 12 monitored groundwater quality parameters can be grouped into three clusters where the concentration of Al and pH level formed a separate cluster. The calculated score values of the Canadian Council of Ministers of the Environment Water Quality Index indicated a deterioration of groundwater quality over the monitoring period.