Bioaccessibility and Health Risk of Heavy Metals at Topsoil in Primary Schools in a Coal Mining City
Thirty nine topsoil samples were collected from a coal mining city of Anhui Province,China.The Physiologically Based Extraction Test (PBET) method (in vitro test) was used to determine the bioaccessibility of heavy metals (Co,Cr,Cu,Ni,Pb,and Zn) at different areas.In addition,the human health risk assessment for children by hand□mouth exposure was carried out based on the human health risk model (US EPA).The results showed that the total concentrations of Co,Cr,Cu,Ni,Pb,and Zn were,respectively,14.73,59.09,40.27,34.38,44.27 and 125.12 mg kg-1.Their bioaccessible concentrations in gastric phase were,respectively,4.88,2.10,4.98,6.31,5.73 and 13.51 mg kg-1 and those in small intestinal phase were,respectively,2.17,1.99,5.43,2.35,3.94 and 3.84 mg kg-1.The bioaccessible concentration of heavy metal (except Cu) was higher in gastric phase than that in small intestinal phase.The multiple regression model among heavy metals,pH and soil organic matter partly could be used to predict the bioaccessibility of heavy metals.The bioaccessibility of heavy metals decreased in the order of Co (46.16％) ＞ Cu (31.83％) ＞ Ni (27.94％) ＞ Pb (26.47％) ＞ Zn (14.38％) ＞ Cr (8.81％).The health risks of heavy metals to children were significantly lower based on their bioaccessible concentrations than that based on their total concentrations.The hazard index (HI) and total cancer risk were decreased,respectively,by 93.68％ and 78.81％.All kinds of assessment indices were within the safe threshold which had little health hazards to children.
PBET testPrimary schoolHeavy metal of topsoilBioaccessibility
NETL
NSTL
万方数据
维普
