R-mode analysis for influencing factors of karst groundwater quality in middle and upper reaches of the Hongshuihe river

To control and manage for groundwater contamination in the middle and upper reaches of the Hongshuihe river,R-mode factor analysis was conducted on 130 samples from this area.Three main factors which affect the quality of karst groundwater are recognized in study area.The first main factor is dominated by Ca2+,HCO-3,total hardness and total dissolved solids,which shows the water-rock interaction.The second factor is made up of K++ Na+,Cl-and NO-3,which reflects agricultural pollution and domestic wastewater in the agricultural area,such as pesticide,fertilizer,and animal waste.The third factor is composed of Mg2+,SO2-4and F-,which reflects industrial and mining pollution in the northern mine area.The results show that these three factors are closely related to human activities,which would be monitored and controlled more strictly in the future.