Heavy metal human health risk assessment and consumer perception of vegetables in Lubumbashi, Democratic Republic of the Congo

In the mining city of Lubumbashi (Democratic Republic of the Congo), intensive mining activities have led to heavy metal contamination of food crops, posing serious public health risks. Using an interdisciplinary framework, this study addresses a critical knowledge gap by quantifying heavy metal concentrations in the six most-consumed vegetables ( Spinacia oleracea , Brassica chinensis , Amaranthus vulgaris , Manihot esculenta , Allium cepa and Solanum lycopersicum ), assessing potential health risks to consumers, and examining perceptions of food-chain contamination in Lubumbashi. Mean concentrations (mg/kg) of Cd, Cu, Pb, and Zn measured by inductively coupled plasma optical emission spectrometry (ICP-OES) in leafy vegetables—particularly Spinacia oleracea (Cd: 4.02; Pb: 1.44; Cu: 25.27; Zn: 136.21)—exceeded the maximum permissible limits established by the Food and Agriculture Organization/World Health Organization. Health risk assessment revealed elevated non-carcinogenic and carcinogenic risks, with hazard quotient (HQ) and hazard index (HI) values exceeding 1. Cancer risk (CR) for cadmium exceeded the acceptable range (10 −6 –10 −4 ) in Spinacia oleracea (6.22 × 10 −4 ), Manihot esculenta (5.05 × 10 −4 ), and Amaranthus vulgaris (3.49 × 10 −4 ). Survey data showed that, despite awareness of contamination risks, consumers continued to prefer high-risk vegetables, particularly Manihot esculenta . Logistic regression analysis indicated that awareness significantly predicted knowledge, risk perception, and adoption of safer practices. More than half of respondents expressed willingness to pay a premium for safer food options, including hydroponically produced vegetables. These findings highlight a critical disconnect between contamination levels, consumer behavior, and risk awareness, underscoring the need for integrated food safety policy interventions in mining-impacted urban settings.