Quality of some commonly consumed "pure" and bottled waters in Ago Iwoye, Ogun State, Nigeria-a comparative study

Abstract

Quality of fifteen different commercial sachet water samples commonly called "pure water" and five different commercial bottled waters from Ago Iwoye, Ogun State were investigated to establish the quality of the products and their suitability for human consumption. Generally, results of some physical parameters such as Electrical Conductivity (EC), Total dissolved Solids (TDS) and pH for the "pure" and bottled water samples were within WHO safe limits for drinking water. There was no bacterial contamination detected in all the bottled water samples while 73.3% of the "pure water" samples had values for total bacterial count well above the recommended value of 100 cfu/ml by the National Agency for Food and Drug Administration and Control (NAFDAC). E. coli was also detected in 40% of the "pure water" samples. Levels of trace metals viz: Cr²⁺, Zn²⁺, Mn²⁺, Cd²⁺, Pb²⁺ and Ni²⁺ were determined in the water samples by Atomic Absorption Spectrophotometry (AAS) after acid digestion and ranged from (ND - 1.30) mg/L, (ND - 0.455) mg/ L, (ND - 0.510) mg/L, (ND - 0.559) mg/L, (ND - 13.534) mg/L, (ND - 0.350) mg/L respectively for the "pure water'' samples and (0.025- 0.135) mg/L, (ND-0.965) mg/L, (0.230 - 0.370) mg/L, (ND - 0.280) mg/L, (ND - 10.707) mg/L and (ND - 0.20) mg/L respectively for the bottled water samples. There were only few violations of the WHO limits for these metals in the bottled water samples compared with the 'pure waters'. This study showed that 'pure water' samples contain higher levels of toxic elements - Cd, Pb and Ni than in the bottled water samples while the essential elements- Zn and Mn needful to the body are more abundant in bottled waters than the pure water samples. Generally, results of the trace metals and microbial analyses showed that bottle water is of better quality compared to 'pure waters'. Pure water is not properly treated and hence not fit for human consumption because of the very high risk factors involved.

Keywords: 'Pure water', bottled water, trace metals, Ogun State, bacteria count.