Analysis of characteristics and genesis of major ions in river water using multivariate statistical analysis: A case study of areas controlled by Wuzhou hydrological station

Wuzhou hydrological station is located in the upper reaches of the Xijiang river, with a catchment area of 327,006 km2, accounting for 94.6% of the Xijiang river’s total catchment. 85% of the water supply for Guangxi comes from this catchment. Thus, it is important to investigate the hydrological aspects of Wuzhou hydrological station. From April 2011 to March 2012 water samples were collected regularly and analyzed. Water quality characteristics were studied by means of multivariate statistical analysis. This paper focuses on the essential characteristics and evolutionary regularity of the water and factors influencing it. The results indicate that,(1) Ca2+ and HCO3- were the major ions in the water. The water chemistry was found to be of Ca2+ + HCO3- type. (2) The concentrations of K+, Na+,Mg2+, Cl- and SO42-were greatly affected by the surrounding environment, while Ca2+ and HCO3- concentrations were stable. (3) The major ions in water from Wuzhou hydrological station were mainly affected by water-rock interaction and ion exchange at the soil surface. Rock weathering and soil ion exchange accounted for 69.34% and 17.10%, respectively.