Bioaccessibility, dietary exposure and human risk assessment of heavy metals from market vegetables in Hong Kong revealed with an in vitro gastrointestinal model

A systematic survey of heavy metal (HM) concentrations and bioaccessibilities in market vegetables in Hong Kong were carried out for assessing potential health risk to local inhabitants. The average concentrations of Cd, Pb, Cr, Ni, Cu, and Zn in nine major groups of fresh vegetable varied within 0.007–0.053, 0.05–0.17, 0.05–0.24, 0.26–1.1, 0.62–3.0, and 0.96–4.3 mg kg−1, respectively, and their average bioaccessibilities varied within 21–96%, 20–68%, 24–62%, 29–64%, 30–77%, and 69–94%, respectively. The bioaccessible estimated daily intakes (BEDIs) of Cd, Pb, Cr, Ni, Cu, and Zn from vegetables were far below the tolerable limits. The total bioaccessible target hazard quotient (TBTHQ) of the six HMs was 0.18 and 0.64 for average and high consumers, respectively, with Cd and leafy vegetable being the major risk contributors. Risk assessment of HMs from foods should be modified by taking bioaccessibility into account.

► 26%, 16%, and 0.56% of vegetables in Hong Kong were contaminated by Cd, Pb, and Cr.
► The average bioaccessibilities of Cd, Cr, Cu, Ni, Pb, and Zn varied within 20–96%.
► The total BTHQ of the six HMs were 0.18 and 0.64 for average and high consumers.
► The Cd and leafy vegetable were the major risk contributors for local inhabitants.
► Human risk assessment should be modified by taking bioaccessibility into account.