DETERMINATION OF HEAVY METAL BIOAVAILABILITY IN ATMOSPHERIC DUST COLLECTED FROM COAL MINING AREAS AND HEALTH RISK ASSESSMENT

This study aimed at investigating the concentrations, chemical fractions, bioavailabilities and health risks of Cu, Pb, Cr, Ni and Cd in atmospheric dust generated in Suzhou coal mining area. 45 dust samples were collected and then analyzed using BCR sequential extraction scheme and the in vitro gastrointestinal test. The results showed that noticeable enrichments of Cu, Pb, Ni and Cd were found in the coal mining areas. Analysis of chemical fractions indicated that Cd was mainly found in the acid soluble fraction, Pb and Cu were mainly found in the reducible fraction, Ni and Cr were mainly found in the residual fraction. The bioavailabilities of the five trace metals were in the following order: Cd>Pb>Cu>Ni>Cr in the gastric phase and Cu>Pb>Cd>Ni>Cr in the intestinal phase. Significant correlation and regression relationships were found between the gastrointestinal phase and reducible fraction for almost all the studied elements, which suggested that most metal ions extracted from the gastrointestinal phase were mainly supplied from the reducible fraction. Finally, the results of the health risk assessment model were assessed and found to be far below 1.0, which indicated that these metals did not pose a significant risk to the local residents.