Investigation of possible human exposure to metals concentration in vegetables

This study assesses the health risk of metals concentration in spinach and onions obtained from different suppliers (suppliers 1, 2, 3, 4 and 5) in Mafikeng, South Africa. The following elemental concentrations of As, Ba, Bi, Cu, Cr, Co, I, Mn, Ni, Pb, Sr, Th, Rb, V and U were tested in spinach and onions using inductively coupled plasma–mass spectrometry (ICP-MS). The result shows that Bi, I, Th, Pb and U were not detected in all the samples of spinach and onions. In spinach, the degree of decreasing abundance is as follows: Mn > Cr > Sr > V > Rb > As > Ba > Cu > Ni > Co, while in onions it is Sr > Mn > V > As > Cr > Cu > Ba > Rb > Ni > Co. The estimated daily intake of metal (DIM) for As and Cr in spinach from suppliers 1, 2, 3, 4 and 5 were higher above the limit values of 0.020 and 0.033 mg/kg recommended by Food and Agriculture Organization (FAO)/World Health Organization (WHO), while, Ba, Cu, Co, Mn, Sr and V were below the limit values. The estimated DIM for As in onions was higher than 0.020 mg/kg recommended by FAO/WHO, while the intake for Ba, Cr, Cu, Mn, Ni, Sr and V were below 0.033, 2-3, 2-5, 01 and 10 mg/kg recommendations by FAO/WHO, respectively. The target hazard quotient (THQ) value in spinach obtained from suppliers 1, 2, 3 and 4 were less than 1, while, the THQ value for Cr is 2.19 greater than 1 in spinach obtained from supplier 5. The THQ value was less than 1 in onions obtained from all the suppliers. Spinach were not suitable for human consumption due to estimated DIM for As and Cr that were higher than the recommendation of FAO/ WHO and THQ value of Cr that was greater than 1. Key words: Spinach, onion, metal, estimated daily intake of metal, target hazard quotient.