Health Risk Assessment of Cadmium in Soils Surrounding Daye Copper and Iron Mining Metallugical Area
In order to more accurately evaluate the health risks of heavy-metal pollution of Cd in the soils surrounding the Daye copper/iron mining metallurgical area to human health,the total amount of Cd,the content of different forms of Cd and the human gastrointestinal availability of Cd in the soils were measured.In addition,based on the models involving tradi-tional health risk assessment,bioavailability assessment,and bioaccessibility assessment,the health risks of Cd in soil were evaluated.Consequently,the study showed that the average content of Cd in the the area was 4.94 mg/kg;and the forms of Cd in soils were allotted in order of decreasing magnitude:residual state>iron/manganese-oxide-bound state>organic bound state>exchangeable state>carbonate bound state;the average value of bio accessibility in the gastric stage was 26.06%,and that of bioaccessibility in the intestine was 43.12%,bioaccessibility in the intestinal stage being higher than that in the gastric stage.The evaluation results of single factor index method suggested that Cd pollution in the soils of the study area was considerably serious,mainly located within the distance of 1 500 m from the region of smelteries.On the other hand,the results of health risk assessment suggested that Cd exposure risks certainly existed in different groups of people of the study area;however,according to the assessment outcome by using three evaluation models the carcinogenic risk at different distanc-es from the study area was in an acceptable range,especially the carcinogenic risk to the adults in the range of 2000m or so was little or negligible.
heavy metalsbioavailabilitybioaccessibilityhealth risk assessment