Sequential Extraction of Nickel in Soil and Fruits

Abstract: The identification of chemical forms of Ni in agricultural samples is of interest for the evaluation of its mobility, bioavailability and ecotoxicity. In this study, the Ni concentration of the fruit and soil samples were determined using Flame Atomic Absorption Spectrometry (FAAS). The soil samples related to the fruits were digested and extracted using different digestion and extraction reagents. The result revealed that the soil samples obtained from various locations contain varying amount of Ni and was distributed between residual, oxide, carbonate and exchangeable fractions. The result also showed that the concentration of Ni in the soil samples recorded was within the allowable limits of 40mg/kg and the ANOVA (p=0.017<0.05), showed that there is significant difference in the concentration of Ni in mango, orange, cashew and pawpaw fruits. Similarly, from the Duncan post hoc test, in the third homogenous subset, mango and orange have the highest Ni concentration followed by pawpaw in the second homogenous subset. In the first homogenous subset, cashew has the least Ni concentration