Identification and quantification of heavy metals in local drinks in Northern Zone of Nigeria

Abstract

Nine heavy metals were studied in locally prepared drinks, namely, “Zobo” and “Kunnu Zaki”. The samples were prepared from the outer covering (calyx) of the fruits of roselle Hibiscus sabdariffa and cereals (millet or guinea corn), respectively. Twenty samples of “Zobo” coded Zb1-Zb20 and twenty samples of “Kunnu Zaki” coded Kz1-Kz20 were bought from different parts of Samaru-Zaria, Nigeria. The qualitative analysis of the samples was by official methods and were quantitatively analyzed using Atomic Absorption Spectrophotometer (AAS). Iron (Fe), Copper (Cu), Zinc (Zn) and Lead (Pb) were detected in most Zb and Kz samples, while Chromium (Cr), Manganese (Mn), Silver (Ag), Mercury (Hg) and Bismuth (Bi) were absent in all the samples. The Fe values ranged from 3.13 to 5.48 mg/L; Cu ranged from 0.12 to 0.62 mg/L, Zn ranged from 0.02 to 0.22 mg/L and Pb ranged from 0.54 to 1.28 mg/L in Zb samples. The Fe values for Kz samples ranged from 18.63 to 31.25 mg/L, Cu ranged from 0.03 to 0.11 mg/L, Zn ranged from 0.08 to 0.39 mg/L and Pb ranged from 0.80 to 1.55 mg/L. The higher values detected in Fe, Zn and Pb for Kz samples compared with Zb samples could be due to the different materials used in their preparation. The implication of the results in public health is discussed.   Key words: Cereals, drinks, heavy metals, samples, Hibiscus sabdariffa.