Evaluation Of Drinking And Irrigation Water Quality And Potential Risks Indices In Tehsil Karak, Khyber Pakhtunkhwa, Pakistan

Abstract

Surface and subterranean water are widely recognized as critical sources of water in Pakistan for agricultural and drinking uses. It is critical to address the characterization of surface and subsurface water for irrigation and drinking reasons. Water samples (n=72) were obtained from diverse sources at different places across the research region for physiochemical analysis. In the current study, effective techniques such as the WATER QUALITY INDEX (WQI), HUMAN HEALTH RISK ASSESSMENT (HHRA), and IRRIGATION WATER QUALITY INDEX (IWQI) were utilized to analyze water quality. The study's findings show that the physicochemical characteristics of the water sources in Tehsil Karak vary significantly. The study revealed that the pH levels of the water samples ranged from 6.5 to 6.9, with the highest values recorded in the hand pump samples. In terms of electrical conductivity, both hand pumps and tube wells exhibited values ranging from 0.33 to 4.75. Similarly, the electrical conductivity range for pressure pumps was also identified as 0.33 to 4.75. Notably, the average conductivity value exceeded the permissible limits established by the World Health Organization (WHO 2011). Regarding salinity, tube wells displayed concentrations ranging between 156 and 1910 mg/L, while hand pumps showed levels from 281 to 737 mg/L, and pressure pumps ranged from 261 to 2370 mg/L. The WQI of samples states that 78.08% of the total groundwater samples are excellent, 9.59 % are good, 4.13 % are fair, 4.13 % are poor and 4.13% are unfit for drinking. The interpretation of the health risk assessment findings points to the possibility of health concerns for specific elements, including aluminum, barium, lead, and strontium, whose concentrations exceed the RfD's (Reference Dose Calculations) safe levels and the sale level of water quality 0.04 mg/kg body weight. However, all samples had unsuitable Residual Sodium Carbonate (RSC) levels, and elevated Sodium content, as indicated by Na%, SAR, and RSC values, poses a significant danger. A Magnesium Hazard (MH) score >50 signifies toxic water, unsuitable for irrigation. The research assists in identifying polluted zones as well as following new remedial strategies to manage the source of pollution in the study area.