Investigation of the presence and health risk assessment of lead in vegetables grown in the vicinity of a lead-zinc mine Kabwe, Zambia.

Mining is one of the main sources of heavy metals that present great harm to human health even in low concentrations. Lead (Pb) contamination of food and especially of frequently consumed vegetables is a growing public health concern worldwide. Although levels of exposure in developed countries have declined over the past decades, the same cannot be said of the developing countries. Health risk assessment has increasingly been employed to determine the potential hazards of heavy metal exposure to humans. In this current study, the aim was to investigate the presence and health risk of Pb in vegetables commonly grown in the vicinity of the lead-zinc mine in Kabwe, with the objectives of assessing the Pb levels in garden soils used for growing vegetables and also analyzing Pb levels in the vegetables commonly grown on household backyard garden. Therefore Pb was measured in edible portions of vegetables (giant rape (brassica napus) and onion (allium cepa)) and soils around the residential areas (Chowa, Kasanda and Mutwewansofu) in the vicinity of the lead-zinc mine plant in Kabwe, Zambia. The results of Pb levels in the backyard soil, where the vegetables samples were randomly picked ranged from 865.7 to 58600mg/kg, all above the maximum permissible limit recommended by
WHO/FAO. The potential health risk of Pb contamination to the local population via vegetable consumption was evaluated. The concentrations in edible portions of vegetables were 2.14 (0 to 9.657 mg/kg) onion (allium cepa) and 2.35 (0 to 9.8 mg/kg) giant rape (brassica napus) respectively. Approximately 71% of the Pb in the vegetables samples exceeded the maximum allowable concentrations by WHO/FAO of 2015. The calculated estimated daily intake or the estimated daily dose of Pb from both onion and giant rape were also higher than the permissible tolerable daily intake PTDI- 0.0035 mg/kg/day of Pb in both adult and children. Target hazard quotient THQ value >1 were also estimated in both children and adults, therefore indicating that, there is a health risk from consumption of these vegetables in these sampled residential areas in the vicinity of the Pb-Zn mine in Kabwe.