A physico-chemical analysis of soil and selected fruits in one rehabilitated mined out site in the Sierra Rutile environs for the presence of heavy metals: Lead, Copper, Zinc, Chromium and Arsenic

Abstract

The accumulation of heavy metals in soils especially in mining environments is of increasing concern to researchers in the Agricultural Industry. This is because the metals are biomagnified by plants. Accumulation of heavy and trace metals in plants occur by various sources but soil is considered the major one. Consumption of vegetables and fruits containing heavy metals is one of the main ways in which these elements enter the human body. Once in the body, heavy metals are deposited in bone and fat tissues, overlapping noble minerals and cause an array of diseases. The present study investigated the concentration of heavy metals that is, Cu, Zn, Cr, As and Pb in soil as well as mango (Mangifera indica L.) and cashew (Anacardium occidentale) fruit samples collected from the Mokaba rehabilitated site in the Sierra Rutile environs, to evaluate the possible health risks to human body through food chain transfer. Atomic absorption spectrophotometry was used to estimate the levels of these metals in the fruits and soil. Results showed that the concentrations of Pb and Cu in both soil and fruits are higher than the World health average values. However, Zn and Cr were found to be below the World health average values, whereas As was not detected. Translocation factors (TF) from soil to fruits were calculated from the data on levels of metals in both soil and fruits. The sampled plants showed high translocation factor values (TF > 1in almost all cases) implying that the plants could be labeled as accumulators of pollution. Pearson's product moment correlation showed a very strong relationship between soil and fruits. It can be concluded that the crops/plants grown in the rehabilitated lands in the Sierra Rutile environs absorb significant levels of some heavy metals from the polluted soil.