Phyto-Availability of Potentially Toxic Metals in Curcubita ficifolia Grown on Contaminated and Non-Contaminated Soils

Abstract

In order to estimate plant available fraction of metals in two soil samples-contaminated soil (A) and non-contaminated soil (B), a vegetable crop,Curcubita ficifoliawas grown on both soil samples. The matured leaf was harvested and analyzed for its metal concentration after three (3) months of growth. The soil samples were collected before and after planting, digested with acid and analyzed to determine the pseudo total metal concentration and quantification was done using atomic absorption spectroscopy (AAS). To correlate metal accumulation by the vegetable with potential bioavailability of metals in soils, sequential extraction (SE) using the modified BCR technique was performed on the soils. Soil sample B was used for quality control. It was observed that each metal differed considerably in uptake. And theC. ficifoliacultivated on soil sample A had tissue concentrations of Zn, Mn and Cu as follows: 39.6mgkg-1, 18.3mgkg-1and 26.3mgkg-1respectively. Also,C. ficifoliacultivated on soil sample B had a lower absorption of Zn, Mn and Cu with concentrations of 10.21mgkg-1, 9.11mgkg-1, and 7.6mgkg-1respectively. Results of sequential extraction showed that Zn for soil sample A, and Fe for sample B were mostly present in the acid exchangeable and reducible fractions where these metals were mostly taken up.