Abstract:
There have been increased concerns on heavy metal contamination in vegetables and the risks associated with them. The present study was carried out to assess the concentrationof some heavy metals which are (Zn, Cu, Pb, Ni, Cd and Fe) in six selected leafy vegetables namely; Corchorus olitorius, Amaranthus spp, Telfaria occidentalis, Talinum triangulare, Solanecio biafrae and Amaranthus hybridus which were collected from six different markets; four from Akure and one each from Ikare and Okitipupa towns. Heavy metals concentration was determined using Atomic Absorption Spectrometer (AAS, VGP 210). The results showed that highest concentrations were observed in Amaranthus spp for four different elements; Zn (2.71mg/100g) at Oja Oba market in Akure, Fe (14.19 mg/100g) at Ikare market, Cu (2.08mg/100g) and Pb (0.13mg/100g) at Shasha market also in Akure. Meanwhile, Ni (0.34mg/100g) was observed at Isinkan markets in Solanecio biafrae. Also, the mean concentration of all the metals analyzed in the leafy vegetables were in the following order; Fe > Zn > Cu > Ni > Pb > Cd. It was observed that Zn, Cu, Ni and Fe levels were within the maximum permissible limits set by FAO/WHO for human consumption. However, Pb was found to be above maximum permissible limits in some samples such as Corchorus olitorius at Oja-Oba and Okitipupa market, Telfairia occidentalis at Shasha markets, Amaranthus spp at shasha and Oja-Oba markets and Talinum triangulare at Isinkan market. Cadmium was observed to be below detection limit in all samples at different location. The daily intake of metal (DIM) and Health risk index (HRI) of these metals through consumption of leafy vegetables from market sites posed no risk or hazard to human health based on the provisional tolerable daily intake (PTDI). However, constant monitoring and proper health risk assessment are necessary to evaluate the levels of metal concentration that could be present in vegetables.
