[Assessment of health risk for mined soils based on critical thresholds for lead, zinc, cadmium and copper].

Contents of heavy metals (Pb, Zn, Cd, Cu) in soils in terms of point, line and area around a lead/zinc mine in Dongguan town, Zhejiang, China, were investigated to evaluate environmental quality based on index and health risk assessment model for safety of soils-human. The order for average contents of Pb, Zn, Cd, Cu in terms of point, line and area were Pb >> Zn >> Cu >> Cd. The contents of Pb, Zn, Cd, Cu in terms of point and line were much higher than that in terms of area, especially Pb and Zn contents. The distribution of soil heavy metals was asymmetric. The calculated critical threshold in soil for adult was higher than that for children. The average order of individual risk index for children and adult health was Pb >> Cd > Cu > Zn. Children were more easily affected by soil heavy metals, for that hazard indexes for children were 3 times of adult health. The environmental quality of Dongguan town was mainly safe correspondingly. The heavy metal environmental quality in terms of point and line near a lead/zinc mine had higher hazard risk and might bring potential hazard to local residents.