Health Risk Assessment of Some Heavy Metals Contamination in Vegetables Sold at Bichi Local Government Area, Kano State – Nigeria

Abstract

Vegetables are the source of essential nutrients for health maintenance and treatment of various diseases. However, they are a major  source of heavy metals contamination. This study evaluates the levels of heavy metals in selected vegetables sold in Bichi and their  potential health risks. The collected samples were ashed using concentrated HNO₃ and analyzed using AAS. The concentrations of the heavy metals detected were in the range of 0.18 to 0.04; 1.64 to 0.63; 0.01; 3.44 to 0.67, and 0.17 to 0.06 mg/kg, for Cu, Fe, Cd, Pb, and Zn  respectively. The concentrations of heavy metals were below WHO/FAO recommended levels except Pb, which is above the tolerable limit.  The highest concentration of Pb (3.44 mg/kg) where detected in pepper, and the least in carrots (0.67 mg/kg). The Estimated Daily Intake values of individual heavy metals from the consumption of vegetables were 1.08 × 10⁻³, 1.66 × 10⁻², 1.42 × 10⁻, 3.52 × 10⁻², and  1.36×10⁻³mg/kg body weight/day for Cu, Fe, Cd, Pb, and Zn respectively which were less than the Maximum tolerable daily intake. The  Hazard Index of all vegetables is 6.83 × 10⁻² which is less than 1, indicating that, the consumption of these vegetables may result in non- carcinogenic health risks. The Target Cancer Risks value of Pb was 2.99 × 10⁻⁷, which is less than the standard risk limit (10⁻⁶). This shows  that, despite the high concentration of Pb in the samples, the calculated parameters have clearly indicated that, there are no carcinogenic  health risks to consumers.