Characterization of controlling hydrogeochemical processes using factor analysis in Puyang Yellow River irrigation district (China)

Abstract

Groundwater chemistry is diverse and complicated and is regulated by both natural hydrogeochemical and anthropogenic processes. Determining the governing processes and their influence on groundwater chemistry is very important to understand groundwater quality evolution and establish reasonable water management strategies. Main cations (Ca2+, Mg2+, Na+, K+, and Sr2+), anions (Cl−, SO2−4, HCO−3, NO−3, and F−), and SiO2 and UV254 of 50 shallow groundwater samples were treated and analyzed. Factor analysis combined with ionic ratio and correlation analysis was used to identify the major hydrogeochemical processes responsible for the variation of hydrochemical components. Approximately 76% of the total variance of the data set can be explained by the four factors identified. Composing of Sr2+, Mg2+, Ca2+, and electrical conductivity (EC), Factor 1 accounted for 25.67% of the total variances, and represented groundwater formation background and fundamental water–soil/rock interaction. Factor 2 with high loadings on NO−3, U(Cl−, SO2−4, HCO−3, NO−3, and F−), and F−)254, and F−, was related to anthropogenic activities, especially the release of domestic sewage and industrial effluents. Factor 3 composed of Na+, HCO−3 and EC was interpreted as cation exchange process. Factor 4 explained 15.75% of the total variance, and was attributed to the influence of agricultural activities, especially chemical fertilizer application.