Human health risk assessment of essential and non-essential metals in vegetables (Jute Mallow, Onions, Celosia, Spinach and Tomatoes) from Ogun, Lagos and Oyo states, southwestern Nigeria

Vegetables are important sources of essential minerals and vitamins required for healthy living. However, contamination of vegetables with inorganic and organic substances may pose severe or irreversible health risk. The present study assessed the health risk of metals in vegetables from three states in southwestern Nigeria. A total of 180 vegetable samples (Jute Mallow, Onions, Celosia, Spinach and Tomatoes) were collected and analyzed for essential {copper (Cu), iron (Fe), nickel (Ni) and zinc (Zn)}, and nonessential {cadmium (Cd) and lead (Pb)} metals using the standard method. The health risk assessment was evaluated for hazard quotient (HQ), hazard index (HI) and cancer risk (CR). Results showed the highest concentrations of Fe in vegetable samples ranging from 4.9 mg kg−1 in jute mallow from Ogun to 558 mg kg−1 in spinach from Lagos. The spinach samples were more enriched in Fe and Zn than any other vegetables. The abundance pattern of metals in vegetables followed the order of Fe > Zn > Cu > Pb > Ni > Cd. The health risk assessment study revealed HQ and HI of metals greater than 1.0 in many vegetable samples indicating non-carcinogenic adverse health effects. The average CR values for Cd and Ni in vegetables were generally higher than the acceptable limit of 1.0 × 10–4, while the mean CR data for Pb were greater than the priority limit of 1.0 × 10–6. These CR values suggested possible cancer development through consumption of vegetables from the study area.