Groundwater Pollution in and Around a Paper Wastewater-Irrigated Area, Northwest China

Groundwater samples were collected from 87 monitoring wells in and around a paper wastewater-irrigated area. The monitored parameters include pH, COD, Cl^-, SO₄^2-, F-, TDS, TH, NH₄-N, NO₃-N and NO₂-N. Water quality variation was examined by graphical approach and R mode cluster analysis. The study shows that groundwater in the study area has been contaminated. Most physiochemical parameters usually have high variations in concentration. Groundwater pollution in the forest area is mainly caused by CODMn, NO₂-N, NO₃-N and F^-, while groundwater pollution in the alluvial plain may be attributed to excess TDS, TH, F^- and NO₂-N. Elevated concentrations of COD_Mn, NO₂-N, NO₃-N is due to anthropogenic intervention, while TDS, TH, pH and Fmay be influenced more by natural processes.