Assessment of groundwater quality in Piryaloi, Pakistan: integrating GPI, SPI, and GIS for comprehensive analysis

ABSTRACT At present, the groundwater quality in various parts of the world is under serious threat. As a result, human health is highly affected. Thus, the present study analyzed and mapped the groundwater quality of Piryaloi, Pakistan using two widely applied indices, i.e., groundwater pollution index (GPI), synthetic pollution index (SPI), and GIS. Water samples were analyzed for various physicochemical parameters such as pH, turbidity, total dissolved solids (TDS), electrical conductivity (EC), chloride (Cl−), calcium (Ca2+), magnesium (Mg2+), total hardness (TH), carbonates (CO32−), bicarbonates (HCO31−), fluoride (F), and heavy metals such as sodium (Na), potassium (K), iron (Fe), manganese (Mn), nickel (Ni), zinc (Zn), molybdenum (Mo), boron (B), arsenic (As), cobalt (Co), copper (Cu), cadmium (Cd), palladium (Pd), and chromium (Cr). According to the GPI, 46.67, 40 and 13.33% of samples were excellent, good, and poor, respectively. Whereas, according to the SPI, 33.3, 40, 20, and 6.7% of samples were suitable, slightly polluted, moderately polluted, and highly polluted respectively. Despite the different inputs to the indices, the proportionate ranking showed a moderate correlation (R2 = 0.62) between the results of both indices. Interpolated maps also depicted that in some areas, groundwater is contaminated, and thus it should be treated well before drinking.