Non-carcinogenic and carcinogenic risk assessment of some heavy metals in carrots selected from Wudil, Kano, Nigeria

Fruits and vegetables contaminated with heavy metals can pose health risks to humans. Noncarcinogenic and carcinogenic risks of some metals (Cu, Cd, Cr, Pb, and Ni) in carrots cultivated in Wudil, Kano, Nigeria was investigated by calculating the chronic daily intake (CDI), target hazard quotient (THQ), hazard index (HI), and carcinogenic risk (CR) of the metals. The mean concentrations of the metals were in the following decreasing order: Cu>Cr>Ni>Pb>Cd. The levels of all the metals were below the maximum tolerable limit set by FAO/WHO. The THQ for the heavy metals were all less than one (THQ < 1), showing that these metals did not constitute a noncarcinogenic risk to the population through the consumption of carrots. The percentage contributions of the metals to the total non-carcinogenic risk were in the following order: Cr>Pb>Cu>Cd>Ni. Cr was the major contributor to the total non-carcinogenic risk and accounted for 57.61% of the total risk, while Pb, Cu, Cd, and Ni contributed 15.64%, 12.76%, 7.41%, and 6.58% respectively. The CR were all below the upper limit of 1×10-4, suggesting that lifetime exposure to these metals through the consumption of carrots did not pose a cancer risk to the population. The levels of the investigated metals in carrots in the area did not pose any risk to the consumers. However, there is a need to monitor the metals on regular basis to ensure the safety of the consumers.