Abstract:
The concentration of heavy metals copper (Cu), zinc (Zn), lead (Pb), manganese (Mn) and cadmium (Cd) was assessed in two leaf vegetables Amaranthus hybridus L.(Green Amaranth) and Telfairia occidentalis Hook. f.(Fluted Pumpkin) from selected markets and vegetable farms in Akure metropolis, Ondo State, Nigeria. This assessment was also done on soil from selected vegetable farms within Akure. Vegetable and soil samples were collected randomly from all the selected sampling sites and were prepared and digested according to the standard procedures recommended by The American Public Health Association. The concentrations of heavy metals present in the vegetable and soil samples were determined using the Atomic Absorption Spectrophotometer. This study reveals the presence of the above heavy metals in all the vegetable and soil samples from various sampling sites.
The results revealed that the concentration of Cu, Zn, Mn and Cd in both Fluted Pumpkin and Green Amaranth were all below the safe limit recommended by WHO/FAO. However, the concentration of Pb in both vegetable species sampled from some markets and vegetable farms were above safe limit of 0.300 mg/kg recommended by WHO/FAO. The concentration of Pb in Green Amaranth and Fluted Pumpkin sampled from the markets are 0.390-0.400 mg/kg respectively and0.400-0.430 mg/kg while their concentrations in vegetables sampled from farms are 0.000-0.600 mg/kg and0.000-0.590 mg/kg respectively. The concentrations of heavy metals in the soil of vegetable farms studied were less than the standard limits recommended by WHO/FAO and National Environmental Standard and Regulation Enforcement Agency (NESREA). However, the concentrations of heavy metals in the soil of these farms in were less than those of the corresponding vegetables cultivated on them.
Considering the regular consumption of these two vegetables in the study area, there is a need for continuous monitoring of the concentration of these heavy metals by the Ministries of Environment and Agriculture.
