Assessment of heavy metals and health risks of street vended foods in the Mangaung Metro Municipality, Free State, South Africa

Abstract

Street food vending is part of the informal sector that plays a significant role 10 in improving socio-economic status of vendors and the food security of consumers. 11 However, this sector faces safety challenges mostly due to anthropogenic activities and 12 the lack of regulation. Chemical and heavy metal contamination from agricultural 13 practices and industrial activities are significant concerns. This study aimed to evaluate 14 heavy metal contamination in commonly vended foods-pap, chicken, pork and 15 moroho/salads- in the Free State, South Africa, and assess the associated health risks to 16 consumers. Shapiro-Wilk’s normality test and Kruskal-Wallis H tests were used to 17 evaluate differences between means, followed by Pairwise Comparison (p=0.05). 18 Results indicated heavy metal contamination in all analysed samples. The overall 19 median and IQR of As, Cd, Cr, Cu, Fe, Pb, and Zn in descending order Fe 4.365(4.424), 20 Zn 3.605(3.711), As 2.653(2.971), Pb 1.095(1.266), Cu 0.271(0.326), Cr 0.212(0.117) and Zn 0.023(0.027) mg/kg. Multiple pairwise comparisons showed a statistically significant difference (p <0.05) for As between all pairs, while other heavy metals showed some variations without statistical significance. The EDI values of pap, chicken, pork and moroho/salads were below the recommended dietary values, suggesting the heavy metals may not pose a public health risk. The health risk assessment through ICLR and Hazard Index (HI) indicated potential cancer and non-cancer risks from heavy metals in street-vended foods, as ICLR≥10-3 and HI >1. This implies that habitual consumers are at risk of non-carcinogenic health conditions