Investigating the contents of Heavy Metals in Edible Portion of Leafy Vegetables Grown Within Lagos State University, Ojo Campus

Abstract

Introduction: Edible plants are the major source of diet, and their contamination with toxic metals mayresult in catastrophic health hazards. This study was conducted to analyse the heavy metal levels in Amanranthus viridis, Celosia argentea, and Ocimum gratissimum grown in selected farmlands around Lagos State University using Atomic Absorption Spectrometers (AAS). Methods: Dry ashing method was used to destroy the organic matter to determine the content of the heavy metals. The level of the following heavy metals (Lead (Pb), Copper (Cu), Iron (Fe) and Chromium (Cr).) were determined in the soil and edible portion of the vegetables. Results: The results showed that the mean concentration of heavy metals dry weight are: Cu(0.072± 0.014 mg/kg), Fe (0.761± 0.140 mg/kg) Pb(0.006± 0.001mg/kg) and Cr(0.008± 0.002 mg/kg) for Amaranthus viridis,0.004± 0.002mg/kg- Pb, 0.113± 0.158mg/kg- Fe, 0.032± 0.003mg/kg- Cu in Celocia argentea, 0.025± 0.004 mg/kg- Pb, 0.111±0.002 mg/kg Fe in Ocimum gratissimum were recorded in Sport center (site A). The value of heavy metal contamination obtained from School gate (site B) ranged from 0.072± 0.006 mg/kg- Pb to 0.742± 0.066 mg/kg- Fe in Amaranthus viridis, 0.007± 0.0 mg/kg- Pb to 0.450± 0.111 mg/kg- Fe in Celosia argentea, 0.030± 0.005mg/kg- Fe to 0.051± 0.044 mg/kg- Pb in Ocimum gratissimum. The value of heavy metal contamination obtained from PPL (site C) ranged from 0.037± 0.004 mg/kg -Cu to 0.559± 0.080 mg/kg- Fe in Amaranthus viridis, 0.011± 0.001 mg/kg Cr to 0.474± 0.151 mg/kg Fe in Celosia argentea, 0.007± 0.008 mg/kg Pb to 0.048± 0.017mg/kg Fe in Ocimum gratissimum. Conclusion:The levels of heavy metals determined in the analyzed Vegetable samples were found to be below the permissible limits set by WHO; hence they are safe for human consumption.