Evaluation of heavy metal contamination and toxicological risk of selected Moringa oleifera products in Southwest Nigeria
Olufunmilayo E. Adejumo , Adewale M. Ogunseye , Oladipo O. Adejumo , John O. Daodu , Ayodele B. Fagbohun and Lateef S. Kasim
1Department of Pharmaceutical and Medicinal Chemistry, Olabisi Onabanjo University, Sagamu Campus, Nigeria.
2Department of Physics and Solar Energy, Bowen University, Iwo, Nigeria
Corresponding author: Olufunmilayo E. Adejumo
Email: funmijumo@yahoo.com; funmijumo@oouagoiwoye.edu.ng;
Phone: +234 8052705549
ABSTRACT
Background: Heavy metals are the main sources of pollution in the environment and its determination is important in enhancing production efficiency in plants.
Objectives: This study determined the concentrations of selected heavy metals, trace and essential elements present in thirteen (13) Moringa oleifera products marketed in southwest Nigeria.
Methods: Each Moringa sample was digested with a mixture of concentrated nitric acid and sulphuric acid (3:1 v/v) and subjected to standard heavy metal analysis using the atomic absorption spectrometric technique. Calibration curves of absorbance against concentration were plotted to determine unknown metal concentration.
Results: The elements analysed were present in varying concentrations. Cadmium concentrations was between 0.0011 to 0.0030 mg/kg, lead ranged between 0.0010 to 0.0110 mg/kg, while calcium ranged between 145.7 to 957.2mg/kg. Copper ranged between 0.35 to 38.9 mg/kg and that of sodium fell between 105.9 to 947.6 mg/kg. Comparison of these concentration values with the World Health Organisation, WHO/Nigerian National Agency For Food And Drug Administration And Control, NAFDAC standards revealed varying levels of compliance with permissible levels set by these agencies.
Conclusion: Based on present safety and permissible standards, the Moringa products selected in the present study were found to be safe for human consumption.
Keywords: Moringa oleifera products; Elemental pollution; Atomic absorption spectrometry, AAS; Heavy metals