Assessment of Trace Elements and their Health Impacts from Vegetable Consumption in the Vicinity of the Lolodorf Uranium Deposit, Southern Cameroon.

Abstract

Plants possess the capability to absorb, translocate, and accumulate significant levels of potentially harmful substances, including trace metals, in their edible tissues, posing health risks to consumers. To assess the concentrations of inorganic contaminants, namely trace metals and their associated health impact on humans in commonly consumed vegetables cultivated in the localities of Mvengue and Awanda, near the uranium-bearing area of Lolodorf (Cameroon), nine vegetable varieties were sampled for Energy Dispersive X-ray Spectrometry analysis. The selected vegetables included cassava leaves (LMA), cocoyam leaves (LXA), bitter leaves (LVE), nalta-jute leaves (LCO), amaranth leaves (LAM), cassava tubers (TMA), cocoyam tubers (TXA), lady's fingers (FAB), and banana plantains (FMU). Trace elements in leafy vegetables were found in varying concentrations, predominantly Fe, Mn, and Zn, while in non-leafy vegetables (tubers and plantains), Fe, Zn, and Ni were most common. The mean concentrations of trace elements Al, Cr, Mn, Th, U, Fe, Ni, Cu, and Zn were determined to be (671.1 ± 11), (3.1 ± 0.5), (117.1 ± 0.7), (0.2 ± 0.1), (2.9 ± 0.7), (292.9 ± 1.0), (9.2 ± 0.8), (11.9 ± 0.8), and (43.1 ± 0.8) mg/kg, respectively. When comparing the obtained results with the WHO/FAO permissible level, it appears that Al, Cr, and Fe represent the main cause of vegetable contamination in the investigated areas. Concentrations ranged significantly, with some samples exceeding WHO/FAO permissible levels: 44% were contaminated with Al (LVE, LCO, LAM, and FAB) and Cr (LXA, LVE, LAM, and FAB), 33% with Fe (LVE, LCO, and FAB), and 11% with Mn (LAM). No contamination was observed for Ni, Cu, and Zn. The hazard index of the examined vegetables was found to increase in the following order: FMU > LMA > LVE > LCO > FAB > TXA > LAM > LXA > TMA, with values ranging from 1.84× ${10}^{-1}$ to 1.3. The hazard index for these vegetables indicated that only plantains had values over 1, suggesting potential non-cancer risks. The aggregate cancer risk associated with Cr, U, and Ni across each investigated sample increased in the following order: TMA > FMU > LMA > TXA > FAB > LVE > LXA > LCO > LAM, with values ranging from 1.04 × 10^-4 to 1.25 × 10^-3, with Ni the primary contributor. Overall, these findings suggest potential cancer risks associated with the consumption of these vegetables. It is therefore recommended that consumers, particularly those who frequently consume plantain from the investigated area, consider moderating their intake as a precautionary measure to mitigate potential health risks associated with chronic exposure to these metals through diet.