Determination of Quality Characteristics Levels in Selected Borehole Water in Nairobi City And its Metro Area

: The main factors influencing the longevity of the life forms are the quantity and the quality of drinking water. Elevated concentrations of quality characteristics such as heavy metal levels, chloride, total dissolved solids, and major ions are known to contribute to cancer, hypertension, kidney failure, lower intelligence, and long-term neurological issues in human beings. Surface water and groundwater are both sources of drinking water. Owing to its low risk of pollution than surface water, groundwater is the more relied-upon of the two sources. Humans have been involved in actions that have contaminated the world for many years. As a result, they permeate the earth’s crust until they reach the groundwater aquifer. This study aimed to assess groundwater viability at multiple locations in Nairobi city and its metro zone and compare the to the World Health Organization’s (WHO) tolerable limit on drinking water. This study analyzed physiological characteristics, chloride ions, and metal levels in four borehole water samples from Nairobi city and its metropolitan area. The water samples were digested using a wet digestion method. Cd, Zn, Cu, Pb, as well as Mn concentrations were determined using an AAS, while Na + and K + levels were determined using an AES. Electrical conductivity ranged from 257.4±0.9 µS/cm 3 to 541.70±2.38 µS/cm 3 , TDS was 128.7±0.83 mg/L to 270.90±1.79 mg/L, while pH was 6.47±0.31to 7.47±0.42. The concentrations of chloride varied from 0.153±0.016 mg/L to 0.268±0.230 mg/L. K + levels varied between 0.31±0.03 mg/L to 1.47±0.03 mg/L, while Pb from BDL-0.167±0.002 mg/L and Zn from BDL- 0.051±0.001 mg/L. The range of Na + levels was 1.64±0.03 mg/L-4.67±0.07 mg/L. Mn levels were found to be 0.139±0.06 mg/L-0.155±0.002 mg/L, Cu ranged from BDL-0.046±0.007 mg/L, and Cd levels were found to be below the limits of detection (LOD) of 0.002 ppm. According to the information that was compiled, the following hierarchy of metal concentrations was observed: Na > K > Mn > Pb > Cu > Zn > Cd. The levels of Cd, Zn, Na, K, and Cu are within the World Health Organization's recommended ranges. Unfortunately, the levels of lead and manganese were greater than the WHO's recommendation. Samples from all boreholes had less than 1000 mg/L of total dissolved solids, suggesting fresh water.