Heavy metal profiles and microbial counts of selected sachet water brands in Birnin Kebbi Metropolis, Nigeria

Abstract

This study evaluated the heavy metal profiles and microbial counts of 10 sachet water brands in Birnin Kebbi, Nigeria, to ascertain the safety of sachet water in the metropolis. Ten brands were randomly selected and assigned codes from KB1 to KB10, after which 15 samples from 3 batches were purchased from the vendors of
each brand, making a total of 150 samples. The samples were analyzed for lead (Pb), copper (Cu), cadmium (Cd), chromium (Cr), nickel (Ni), and iron (Fe) concentrations by atomic absorption spectroscopy. The bacterial count as well as coliform and yeast counts were also determined using standard protocols. The mean values of the data obtained from both analyses were then compared with World Health Organization (WHO) drinking water standards. The results showed KB2, KB4, KB7, and KB8 contained Pb above the WHO limits of ⩽ 0.01 mg L^-1. Cu and Cd were detected in all the brands at concentrations within the WHO limits of £ 1.0 mg L^-1 and ⩽ 0.003 mg L^-1 , respectively. The levels of Cr in KB1, KB3, and KB8 were higher than ⩽ 0.05 mg L^-1 WHO limits, while other brands were within the range. KB3, KB4, KB5, and KB7 exceeded £ 0.02 mg L^-1 WHO limits for Ni. In the case of Fe, only KB8 and KB9 were found within the normal range of £ 0.3 mg L^-1 . All the brands had bacterial counts above the WHO limits (⩽ 100 cfu ml^-1), and only KB6 had coliform counts higher than the WHO limits (⩽ 0 cfu ml^-1). Of all the brands, only KB3, KB7 and KB10 contained yeast beyond the WHO limits (⩽ 50 cfu ml^-1). These results showed the water samples were seriously contaminated, and the water brands could pose a significant public health risk to the consumers in the city if this trend continues.

Keywords: Bacterial count, Heavy metals, Microbe, Sachet water, Serial dilution