Assessment of Heavy Metals Concentration and Health Risks of Selected Vegetables Sold In Jos Metropolis

Abstract

This study revolved around environmental pollution caused by heavy metals and the health risks posed to humans by the consumption of contaminated vegetables commonly sold in Jos, Nigeria. Vegetables studied (Apium graveolens - Celery, Hibiscus cannabinus - kenaf, Hibiscus sabdariffa - Sorrel or Roselle, Allium fistulosum - Spring Onions leaves and bulbs, Sesamum radiatum - Sesamum leaves) were obtained from major markets within Jos metropolis. They were washed, air-dried, homogenized, and stored in air-tight bottles. Their concentrations of heavy metals (Zn, Fe, Mn, As, Cd, Pb, Cr, and Cu), were determined using a graphite furnace atomic absorption spectrophotometer, and their health risks were evaluated through daily intake and hazard quotient. The vegetables analyzed gave different concentrations of heavy metals with their values falling within the FAO/WHO permissible limits. The highest concentration of Iron (0.515±0.003 mg/kg) and Cadmium (0.095±0.006 mg/kg) were found in Celery, while Kenaf had the highest copper (0.030±0.008 mg/kg) concentration. Zinc was higher in all the vegetables when compared to the other metals. The daily intake values of all the metals examined exceeded the maximum tolerable daily intake (MTDI) except for copper. Hazard quotient values of all the metals were less than 1 except As, Cd, and Zn which were found to be greater, thereby signifying health risk potentials of these metals. The study, therefore, revealed that consumption of these vegetables could constitute potential health hazards to the well-being of the consumers.