Assessment of Chemical Contaminants in Street-vended Foods and Associated Dietary Health Risks in Port Harcourt Metropolis, Rivers State, Nigeria

Abstract

Background: Street-vended foods constitute an important source of affordable meals in urban centres but may contain chemical contaminants that pose potential public health risks. Aim: This study assessed the levels of chemical contaminants in street-vended foods and evaluated the associated dietary health risks among consumers in Port Harcourt Metropolis, Rivers State, Nigeria. Materials and Methods: Sixty composite samples representing ten commonly consumed street-vended food categories were collected from major vending locations within Port Harcourt Metropolis. Physicochemical properties were determined using standard analytical procedures. Heavy metals were quantified using inductively coupled plasma–optical emission spectrometry, whereas polycyclic aromatic hydrocarbons, pesticide residues and selected organic contaminants were analysed using gas chromatography–mass spectrometry. Estimated Daily Intake (EDI), Target Hazard Quotient (THQ), Hazard Index (HI) and Incremental Lifetime Cancer Risk (ILCR) were calculated using health risk assessment models of the United States Environmental Protection Agency. Statistical analyses included one-way analysis of variance, Pearson correlation analysis, principal component analysis and hierarchical cluster analysis. Results: Lead concentrations ranged from 0.16 to 0.58 mg/kg, cadmium from 0.02 to 0.11 mg/kg, chromium from 0.36 to 1.04 mg/kg, and iron from 20.86 to 52.84 mg/kg. Total polycyclic aromatic hydrocarbons varied between 17.20 and 65.99 µg/kg, while total organic contaminants ranged from 12.84 to 32.42 µg/kg, with the highest concentrations recorded in suya and roasted fish. Lead exceeded the recommended permissible limit in three food samples, whereas cadmium exceeded the limit in one sample. Hazard Index values for children ranged from 0.48 to 1.24, with suya, roasted fish and shawarma exceeding the acceptable threshold. Incremental Lifetime Cancer Risk values ranged from 2.84 × 10⁻⁶ to 6.28 × 10⁻⁵, remaining within internationally acceptable limits. Conclusion: Street-vended foods marketed in Port Harcourt contained measurable levels of heavy metals, polycyclic aromatic hydrocarbons and organic contaminants. Although most contaminant concentrations and carcinogenic risks remained within acceptable limits, elevated dietary exposure associated with selected roasted foods highlights the need for routine monitoring, improved food preparation practices and strengthened food safety regulation.