Assessment of Water Quality in Pangani, Kayole and Dandora Boreholes in Nairobi County, Kenya

Abstract

This study was done to assess the physical-chemical properties of some boreholes in Pangani, Dandora and Kayole in Nairobi County, to assess the content of some heavy metals in some boreholes in Pangani, Dandora and Kayole and to determine the bacteriological quality of the water. These were checked for compliance as per the World Health Organization’s guideline values. Borehole water samples were collected from Dandora, Kayole and Pangani. Water parameters determined included electrical conductivity, total suspended solids, total dissolved solids, pH, fluoride, chloride, ammonia, nitrate, Escherichia-coli, total count and analysis of some selected heavy metal ions. The measurements of pH, fluoride, and electrical conductivity were made by an ion-selective electrode. The determinations of total dissolved solids and total suspended solids were made by the gravimetric method. The titration method was used to quantify chloride, while ultraviolet-visible spectrophotometer was used to measure ammonia and nitrate. E. coli and total counts were ascertained by the biological method. Heavy metals were measured using atomic absorption spectrophotometer. All boreholes met the guideline values of WHO with regard to pH, electrical conductivity, total dissolved solids, chloride and ammonia. Total suspended solids were found to be above the recommended limits of WHO. Nitrate values in all the borehole conformed to the WHO guidelines. Escherichia coli conformed to WHO guideline except at Pangani Borehole 2. Total coliforms did not conform to the set WHO limit values. The concentration of zinc conformed with the set limit values except that of Pangani Borehole 1, Pangani Borehole 2 and Pangani Borehole 3. Concentrations of lead and cadmium in all the boreholes did not conform to the WHO guideline values. It is recommended that the boreholes at Dandora, Kayole and Pangani should not be used for drinking by humans since these heavy metal ions found in the boreholes have a detrimental effect on human health.