Heavy Metal Concentrations in Various Species of Onion Bulbs in (Allium Spp.) Lapai Market, Niger State, Nigeria

Abstract

Hauwa, I. Muhammad, M. Musah, and S. Abdulfatai

In order to evaluate the levels of heavy metal concentration in various species of onions, this study was implemented using three varieties of onion bulbs (Bermuda onion, Spring onion, Vidalia onion), gotten from some local markets within Niger State, They were analysed for their content of Cd, Cr, Pb, Cu, Zn and Fe using dry ashing and wet digestion methods.   Variation in trend of mean concentrations of heavy metals obtained in the order: Fe (312.57ppm) > Zn (18.50 mg/kg) > Cu (13.50 mg/kg) > Cr (12.88 mg/kg) > Cd (4.85 mg/kg) and Fe (312.12 mg/kg) > Zn (17.98 mg/kg) > Cu (13.10 mg/kg)> Cr (12.15 mg/k ) > Cd (4.71 mg/kg) for results obtained after dry and wet ashing digestion methods respectively. There was no significant difference between the concentrations of heavy metals obtained both digestions method and between the concentrations of metals among the three species of onions. However, concentrations of Cd and Cr were above the FAO/WHO recommended limits for metals concentrations in vegetables.