Bioaccessibility of heavy metals in vegetables and its association with the physicochemical characteristics

The bioaccessibilites of heavy metals in vegetables grown around a waste-incinerator site were estimated using the physiologically based extraction test (PBET) method, to assess potential health risk to the local consumers. The average gastric and intestinal bioaccessibilities of Cd, Cr, Cu, Ni, and Pb in vegetables varied within 3.2-9.4 and 0.8-5.3 %, 1.4-2.3 and 1.1-1.9 %, 25-46 and 13-26 %, 6.6-30 and 2.6-5.3 %, 11-29 and 7.1-23 %, respectively. Strong negative correlations were found between electrochemical potential (ΔE 0) and bioaccessibility for leaf mustard samples (r (2) = 0.857) and leaf lettuce samples (r (2) = 0.696). In addition, softness index (σp) and electrochemical potential (ΔE 0) exhibited a moderate but not significant relationship with bioaccessibilities on the basis of the multiple regression analysis (0.05 < p < 0.1). The total bioaccessible target hazard quotient (TBTHQ) of the five heavy metals was 2.5, with Pb being the major risk contributor. According to the TBTHQs of each group of vegetables, local consumers are experiencing adverse health effects by consuming most of the vegetables around waste-incinerator site.