Evaluation of groundwater quality of Mirpurkhas District, Sindh, Pakistan, for drinking, irrigation and multivariate analysis

Water quality is truly essential for safe health and a basic requirement for different purposes. The 54 samples were collected from Mirpurkhas District, and sources of water were mainly hand pumps and bore pumps; mostly, these were used for human consumption and irrigation. The samples were collected from three subdistricts Mirpurkhas (18), Kot Ghulam Muhammad (20) and Shujabad (16). The samples were analyzed for 26 different parameters using standard analytical procedures. The samples on basis of total dissolved salts (TDS) (World Health Organization (WHO) limit of 1000 mg/L) were acceptable for drinking in the range of 22–55% within three subdistricts. The groundwater indicated acceptable alkalinity for 37.5–55%, chloride for 38.8–75%, sulphate 66–75%, Na 43.75–70%, K 22.2–37.5%, Ca 66.6–75%, Mg 72–75%, Cr 12.5–22.2%, Cd 25–38.8%, Pb 55.5–68.75%, Ni 37.5–40%, fluoride 55.5–81.1% and arsenic 85–100% samples within the permissible limits of WHO for drinking purposes. The results of analyses for nitrate, nitrite, orthophosphate, total phosphate, pH, Fe, Cu, Mn and Co for all the samples were within the acceptable limits of WHO. The results were analyzed for multivariate statistical procedures, including coefficient of correlation, Piper diagram, principal component analysis, dendrogram and Gibb’s diagrams. The quality of groundwater depended on the rock dominance and several parameters correlated with each other indicating resemblance in geological settings in the area. The water quality index (WQI) for the samples was also calculated, and 61% of samples were in the excellent to good water category. The suitability of groundwater samples for irrigation based on sodium percent (Na%), sodium adsorption ratio (SAR), Kelly’s index (KI), permeability index (PI) and Wilcox diagrams indicated that 39–95% were suitable for irrigation.