Physicochemical quality and heavy metal contamination of selected bottled water brands in Kano metropolis, Nigeria

Abstract

The physicochemical characteristics of drinking water samples (A, B, C, and D) produced in Kano city were examined in this study in order to determine their safety and quality for human consumption. Total dissolved solids (TDS), electrical conductivity (EC), pH, sulfate (SO₄), nitrate (NO₃), phosphate (PO₄), total hardness, and specific heavy metals (Zn, Pb, Mg, Cu, and Cd) were among the parameters that were examined. According to the results, sample A had the highest pH of 6.74 and sample D the lowest value of 5.76.  Sample B had  0.298 ds/m  and  181.15 mg/mL  for EC and TDS respectively, indicating a higher dissolved ion content. EC and TDS varied considerably among samples. Whereas the quantities of phosphate and nitrate varied, sample B had the greatest nitrate concentration, whereas the concentrations of sulfate were comparatively constant across samples. Samples A, B, and D had significantly higher total hardness values, indicating higher mineral content. All samples had detectable levels of Mg and Zn, according to heavy metal analysis; sample D had the highest value of 5.75 mg/mL of Mg level. Cu and Cd were below detection limits in all samples, however Pb was only found in sample C at a low concentration of 0.023 mg/mL. Although variations in mineral and anion concentration indicate the necessity for routine monitoring to maintain consumer safety in Kano city, overall, the bottled water samples complied with acceptable quality criteria.