Determination of the levels of heavy metal (Cu, Fe, Ni, Pb and Cd) up take of pumpkin ( Telfairia occidentalis  ) leaves cultivated on contaminated soil

The aim of this study was to use AAS to determine the levels of concentration (g/kg) of heavy metals: copper (Cu),Iron (Fe), Nickel (Ni), lead (Pb) and Cadmuim (Cd) uptake by pumpkin (Telfairia occidentalis) leaves cultivated in Pots containing varying concentrations of contaminated soil samples labeled A to E. The results showed that leaves from soil sample A had heavy metal concentration level of Cd: 0.268, Ni:0.040, Pb:0.033, Fe:0.025 and Cu: 0.003. The order of uptake was Cd > Ni> Pb> Fe> Cu. In soil sample B, the concentration level of the metals were Fe:0.091, Cd:0.406, Ni:0.118, Pb:0.058 and Cu:0.006. The order of uptake was Cd> Fe>Ni> Pb> Cu. Results from soil sample C showed that the level of heavy metal concentration in the leaves were: Fe:0.311, Cd:0.380 Pb:0.204, Ni:0.116 and Cu:0.029. The order of uptake is Cd> Fe> Pb> Ni> Cu. In soil sample D, the results were Fe:0.101, Cd:0.087, Ni:0.070, Pb:0.07 and Cu:0.004. The order was Fe> Cd> Ni= Pb> Cu. The results from soil sample E gave the concentration levels as Fe:0.266, Cd:0.135, Ni:0.122, Pb:0.017 and Cu:0.004. The order of uptake was Fe> Cd> Ni> Pb> Cu. The result for the uncontaminated soil sample F, showed that the heavy metal concentration levels were Fe:0.035 Cu:0.003, Pb:0.008, Cd:0.050 and Ni:0.008. The order of concentration levels was Cd> Fe> Ni= Pb> Cu. The findings of this study reveal that pumpkin leaves biaccumulate Cd more, followed by Fe while Cu was the least. Consequently, any agricultural soil suspected to have high concentrations of Cd, Fe, Ni and Pb will not be suitable for use in the cultivation of pumpkin leaves meant for human consumption or animal feed. This because the ingestion level of these metals are far above the WHO tolerable limit. However, pumpkin plants can serve as a good scavenger of Cd and Fe in polluted soil.