Uptake of trace elements by vegetable plants grown on agricultural soils: Evaluation of trace metal accumulation and potential health risk

The current study investigated the concentration of trace elements in agricultural soils, water and agricultural produce collected from Port St. Johns, Eastern Cape (South Africa). Also, the potential health risk associated with consumption of vegetable crops contaminated with trace metals was investigated. The results obtained from the study revealed the presence of most trace metals in soil, water and vegetables samples (spinach). For instance, metals such as Zn, Se, Ni, Mn, Fe, Cu and Cr were detected in spinach samples and were found to be below maximum permissible level according to World Health Organization (WHO) guidelines. This implied that this agricultural produce was safe for human consumption. Similar results were obtained for soil samples, suggesting that the soil is not heavily contaminated by As, Cr, Co, Cu, Fe, Mn, Ni, Pb, Se and Zn. Furthermore, trace metals in water samples were found to be below the maximum allowed limit set by the Department of Water and Sanitation (South Africa). The calculated bioaccumulation factors (BF) from soil to leafy vegetables revealed that spinach excludes the As, Cd, Co, Cr, Cu, Ni and Pb were during metal transfer process while it accumulates Fe, Mn, Se and Zn. Furthermore, health risk index did not demonstrate any health risk to local consumers.