Health implications of heavy metal contamination in urban vegetables: Assessing the risks in Kinshasa and Lubumbashi

Abstract The contamination of edible vegetables with heavy metals is a significant global environmental and public health issue. These inorganic pollutants persist in the environment, accumulate in human tissues, and pose serious health risks. This study aimed to assess the levels of heavy metals such as aluminium (Al), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), selenium (Se), and zinc (Zn) in leaves of Brassica oleracea, Hibiscus sabdariffa L., Amaranthus sp., and Ipomoea batatas leaves. The samples were collected from urban markets in Kinshasa and Lubumbashi, two major cities in the Democratic Republic of Congo. The microwave digestion system was used to extract metals from the samples, and the concentrations of heavy metals were measured using advanced spectroscopic techniques. The detected concentration ranges (in mg/kg dry weight) were as follows: Pb (0.23–1.76), Cd (0.31–1.73), As (1.16–7.19), Fe (22.69–94.22), Zn (17.75-375.01), Al (18.78–93.62), Cr (0.15–0.77), Cu (1.88–16.17), Mn (7.03-153.89), and Se (0.51–3.17). The health risk assessments revealed significant non-carcinogenic and carcinogenic risks to local populations, particularly from Pb and As exposure. These findings highlight the urgent need for regulatory measures to reduce heavy metal exposure from consuming vegetables in urban areas, aligning with global health and sustainability goals.