Determination of Heavy Metals in Public Tap Water in Ibadan Metropolis, Southwestern Nigeria

Abstract

The quality of public taps water transiting from the point of distribution to the end users was analyzed in this study to assess the level of chemical contamination en route, and the result obtained were compared with WHO and NIS/SON recommended standards for drinking water. Sixteen samples were collected from five different areas and the distribution point following standard procedure. The water samples were digested and analyzed for physicochemical properties and heavy metals concentration. The heavy metals determination was done using Atomic Absorption Spectrophotometer, Perkin Elmer A Analyst 200 model. In all the samples analyzed, the physicochemical properties which include pH, Total Solids (TS), Total Dissolved Solids (TDS), and Total Suspended Solids (TSS) were within the WHO and SON recommended limits. The heavy metals determined were lead (Pb), cadmium (Cd), Iron (Fe), and zinc (Zn). All the heavy metals determined were within the recommended limits at the distribution point except Pb 0.030 mg/l. Values higher than the recommended limits were observed for Pb (0.060 to 0.290 mg/l) and Cd (0.002 to 0.008 mg/l) at consumers end. The lowest value for lead 0.030 mg/l was observed at the distribution point and highest at Apata area. The highest value of cadmium was observed at Molete area and lowest at Eleyele area. Elevated levels of heavy metals in the public drinking water sampled as compared to the one obtained from the distribution point suggest likely contamination of the water during transit which may be due to the effect of rust pipes and fixtures, contamination from run offs from dumpsites and roadsides which enters the water through burst pipes. Therefore constant monitoring of the supply and distribution system is essential in order to safeguard the health of the consumers of this public potable water.