Assessment of Water Quality in Some Distribution Tankers and Boreholes in Selected Areas of Nairobi County

Abstract

The health of any community entirely depends on the availability of sufficient safe and clean water which helps in preventing waterborne diseases. This study's primary goal was to determine whether water from distribution tankers and boreholes in a few locations in Nairobi County complied with the World Health Organization and National Environment Management Authority’s established guideline values. Samples were collected from boreholes and distribution tankers as follows: Dandora Boreholes (DB) and Dandora Tankers (DT); Kayole Boreholes and Kayole Tankers; Pangani Boreholes and Pangani Tankers; Eastleigh Boreholes and Eastleigh Tankers; South B Boreholes and South C Tankers in Nairobi County. The parameters determined included: pH, Total suspended solids (TSS), Total dissolved solids (TDS), Electrical conductivity (EC), 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 TDS and TSS were made through 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 and tankers met the guideline values of NEMA, KEBS and WHO with regard to pH, EC, TDS, chloride and ammonia. Total suspended solids were above the recommended limits of KEBS and WHO for the borehole and tanker sites. Nitrate values in all the borehole sites conformed to the WHO, NEMA and KEBS guidelines except at site PB1, while nitrate values for tanker sites conformed to the WHO except at site ET3. It also conformed to NEMA and KEBS guidelines except at sites KT1, KT2, ET3 and SCT1. Escherichia coli in all boreholes conformed except at Pangani Borehole 2. E-coli in tankers conformed except at sites KT1, PT1 and SCT1. Total coliforms for both water samples from boreholes and Tankers did not conform to the set limit values. The concentration of zinc in boreholes conformed with the set limit values except that of PB1, PB2, PB3 and EB2. In tankers, all conformed to the set limit except STT3, PT1, ET1, and ET2. Concentrations of lead, copper and cadmium in both boreholes and distribution tankers did not conform to the limit values.