Abstract

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.