Estimation of Potential Health Risk Due to Consumption of Carrots, Cabbage and Onions Grown in Challawa River Basin Around Challawa Industrial Layout, Kano, Nigeria

Contamination of food by heavy metals has made dietary intake one of its major entry routes into humans. Contents of lead, cadmium , chromium and zinc in carrots, cabbage and onions grown in Challawa River basin around Challawa industrial layout Kano was measured to estimate potential public health risk using Shimadzu atomic absorption spectrophotometer (model AA-6800, Japan) after wet digestion. The ranges of concentrations (mg/kg) were: (Pb) 0.34-1.03, (Cd) 0.20-0.36, (Cr) 1.19-3.76 and (Zn) 2.09-4.54 for carrots, (Pb) 0.46-0.76, (Cd) 0.21-0.51, (Cr) 0.24-0.47 and (Zn) 1.87-5.32 for cabbage and (Pb) 0.56-0.95, (Cd) 0.01-0.16, (Cr) 0.34-0.56 and (Zn) 5.23-19.43 for onions. Lead and cadmium concentrations were found to be above WHO/FAO permissible levels except for cadmium in onions. Zinc content of onions was also above acceptable limits. The average values of Estimated Daily Intake (EDI) of the metals were above the recommended daily intakes (RDI) and upper tolerable daily intakes (UL), except for zinc in carrots and cabbage. The average Target Hazard Quotient (THQ) of lead and cadmium for the crops were found to be above 1.00 indicating potential health risk, cadmium in onions being the only exception. Hazard index (HI) for a typical adult of body weight 70 kg considered in this study was found to be 2.74 for carrots, 3.05 for cabbage and 2.02 for onions. The study concludes that perennial intake of these vegetables from the study area is likely to induce serious adverse health effects.