An evaluation of drinking water quality in five wells in Sebha city, Libya, using a water quality index and multivariate analysis

Sebha city is situated on Southwest Libya’s north edge of the Murzuk basin. Groundwater is the sole source of drinking water. Therefore, assessing its quality for drinking is an essential step. This study was conducted in 2019 to investigate the water quality of different locations in the city. Collected water samples were analyzed for major cations and anions as well as the physicochemical parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS), and total hardness (TH) using conventional standard methods. Water suitability for drinking is based on EC, TDS, and the water quality index (WQI). The abundance of the major ions was as follows: CI − > K + > SO 4 −− > Na + > Ca ++ > NO 3 − > Mg ++ > HCO 3 − , their concentrations were higher than the permissible limits of WHO and Libyan Standards, except in the wells of Alnaserya and Hejara. The TDS levels varied from 1400 to 3704 mg/L, suggesting that the water is mildly salty. The EC ranged from 2188 to 5632 μS/cm, indicating that the water is slight to moderately mineralized. According to the WQI, the water in Hejara and Alnaserya is of good quality, whereas in Sahba, Abedalkafi, and Aljaded, it is of poor quality. Principal component analysis (PCA) exhibited three major components of the factor analysis that accounted for 98.079% of the total variance. The key factors impacting groundwater quality are natural mineral dissolution, weathering of the carbonate system, and anthropogenic activities. Therefore, we deduce that water quality varies across Sebha city’s wells.