| A systematic survey on Hg, Cd, Pb, Cr and Cu concentrations in four kinds of vegetables (120 individual samples involved) and their corresponding soils at 30 sampling sites in the fragmentary vegetable plots of Yuzhong county, Gansu Province, was conducted for assessing heavy metals pollution, bio-concentration ability, and potential health risk to local inhabitants due to exposure via consumption of vegetables. The results showed that the average concentrations of Hg, Cd, Pb, Cr and Cu in soils in the studied vegetable plots were 0.159, 0.364, 15.001, 37.633 mg·kg-1 and 31.298 mg·kg-1, respectively. Pb and Cr concentrations in soils were all lower than the background values of soil in Lanzhou city, but Hg, Cd and Cu contents were higher. The average concentrations of Hg, Cd, Pb, Cr and Cu in vegetables were 0.0037, 0.0115, 0.0293, 0226 mg·kg-1 and 0.1874 mg·kg-1 fresh weight (FW), respectively, which were all lower than the maximum levels of contaminants in foods. Their single pollution indexes were 0.37, 0.06, 0.10, 0.05 and 0.02, respectively, and the integrated pollution index was 0.60. The average bio-concentration factors (BCFs) of Hg, Cd, Pb, Cr and Cu in vegetables were 0.023, 0.033, 0.002, 0.001 and 0.006，respectively, and the order of the BCFs in vegetables was Cd＞Hg＞Cu＞Pb＞Cr. The mean daily intake (DI) of Hg, Cd, Pb, Cr and Cu from vegetables was 1.11, 3.45, 8.79, 6.78 μg·d-1 and 56.22 μg·d-1 for adult residents, respectively, which only accounted for 2.58%, 5.75%, 4.11%, 3.39% and 0.47% of acceptable daily intake (ADI), respectively. The target hazard quotients (THQs) of Hg, Cd, Pb, Cr and Cu were 0.03, 0.06, 0.04, 0.04 and 0.01, respectively, and the total THQ (TTHQ) of heavy metals was 0.17. Therefore, the health risk posed by heavy metals was very low for habitants consuming vegetables. |