Level of heavy metals in sliced watermelon fruits in selected markets in Akure, Nigeria

Abstract

BackgroundFruits are increasingly becoming important dietaries in Nigeria because of its nutritional importance and one of the most sliced fruits that are highly purchased in Nigeria today is watermelon. Nevertheless, consumption of heavy metal contaminated fruits could pose a risk to human health. Therefore, the aim of this work was to determine heavy metal contamination in sliced watermelon fruits in selected Nigerian markets to ascertain their public health safety before consumption.MethodsA total of 54 sliced watermelon fruits were randomly sampled from six different vendors (A –F) in each of the selected markets (Isinkan, Shasha, and Oja-Oba). Samples were digested and analyzed for heavy metal concentrations using atomic absorption spectrometry (AAS) and values compared with WHO (World Health Organization) permissible levels.ResultsThe nickel (Ni) levels detected in the sliced fruits across the markets ranged from 0.20 ± 0.01 (Isinkan) to 1.42 ± 0.02 mg kg−1 (Oja-Oba), while chromium (Cr) levels detected ranged from 0.04 ± 0.01 (Shasha) to 0.12 ± 0.02 mg kg−1 (Oja-Oba). Copper (Cu) levels ranged from 0.04 ± 0.00 (Isinkan) to 0.13 ± 0.03 mg kg−1 (Oja-Oba). Remarkably, cadmium and lead were not detected in any of the sliced fruits. Additionally, the levels of Cu in this study were generally below the WHO permissible levels. However, the levels of Ni in all the sliced watermelon fruits, aside the one purchased from vendor D in Isinkan market, were found to be above the permissible levels. Similarly, Cr levels in the sliced fruits purchased only from vendors A, E, and F in Shasha and vendor C in Oja-Oba markets were also found to be above the permissible levels.ConclusionThis research work provides valuable information on heavy metal contents of sliced watermelon fruits in Akure markets when compared with WHO permissible levels. Fruits with higher values of these metals could constitute health hazards when such fruits are consumed. Hence, there is need to monitor the levels of these metals in sliced fruits from exceeding the acceptable levels as established by regulatory agencies.