Water Quality of Selected Water Sources in Kajiado North Constituency in Kenya: Analysis of Critical Pollutants for Multipurpose Use

Abstract

Access and availability of safe clean water plays a critical role in human life. Due to various anthropogenic activities and natural causes, the available limited sources of water are usually contaminated through point and non-point sources. As a result, frequent
monitoring of these water sources is fundamental in order to ascertain the quality for domestic and other purposes. The study evaluated the water quality from selected sources (surface water, dams, and boreholes) in Kajiando North Constituency by analyzing selected anions and metals ions. Physicochemical characteristics were analyzed using standard procedures, selected heavy metals (Fe, Mn, Cu, Zn, Pb and Cd) and Mg were quantified by ICP-OES, and selected anions using a multi-parameter
spectrophotometer. EC and pH were within recommended levels, except for one site with pH of 9.6. NO2- and Cd2+ were below detectable levels. Detected amounts of SO4 2-, NO3-, Cl-, CO32-, HCO3 -, Zn2+, Cu2+, Mn2+ and Mg2+ were within recommended limits by WHO. F-, Fe and Pb2+ were detected at levels above the maximum allowable limits in some sampling sites. For F-, only 4 out of the 25 sites had values below maximum allowable limits, whereas 3 and 5 sites recorded concentrations above the maximum limits for Fe and Pb2+, respectively. Out of the 25 sampling sites, only 4 (16%) could be considered as having required water quality. Further results from Spearman's correlation analysis showed positive correlations (r2 values of 0.4, 0.5, 0.6, 0.68, 0.70, and 0.76, respectively) between pH-F-, pH-Zn, Cl-- HCO3 -, Cl--Mg, Fe-Mn, SO4 2--Fe, and SO4 2--
Mn, pointing to comparable sources of ions in the water systems. Though further analysis including other diverse parameters such as the microbial quality are needed, obtained results show that the quality of selected water sources is of major concern, especially the fluoride content.