POPULATION MONITORING - EXPERIENCE WITH RESIDENTS EXPOSED TO URANIUM MINING MILLING WASTE/

More emphasis should be placed upon using biomarkers to address potent ial health risk among populations exposed to high concentrations of en vironmental toxicants. Among these studies, those which integrate expo sure measurements with analyses of validated biomarkers may provide mo re reliable information for risk assessment and disease prevention. We have used a multidisciplinary approach to elucidate potential health hazards in a population living around uranium mining/milling facilitie s. The study included 24 target and 24 control residents who were matc hed for age and gender and selected based on time of residence in the study areas and proximity to mining/milling sites. Environmental sampl es were analyzed for uranium-238 (U-238) concentrations and lead isoto pe ratios using inductively coupled plasma-mass spectrometry (ICP-MS) procedures, and blood samples were collected for cytogenetic analysis. We found that the U-238 concentrations in soil samples were significa ntly higher than those in the control areas. In addition, the concentr ations in the surface soil were significantly higher than in the subsu rface soil (p < 0.05) from target areas indicating environmental conta mination by the mining/milling activities. Lead isotope data from soil samples taken near a railroad transfer location was significantly dif ferent from those of other sites, indicating contamination by non-nati ve ore transported from sources outside of the region to local milling facilities for processing. Therefore, local residents have been expos ed to low levels of radioactive contamination from the mining/milling activities on a daily basis for many years. From our cytogenetic analy sis, the target population had more chromosome aberrations than the co ntrols, although the differences were not significant (p < 0.05). Howe ver, using our challenge assay, cells from the target population had a significantly abnormal DNA repair response, compared to cells from th e same control population. In conclusion, the observed environmental c ontamination by uranium is consistent with the observed genotoxic effe cts in the target residents. Therefore, the residents have increased h ealth risk and some of the health problems will most likely be related to exposure to the radioactive contaminants. Since the chromosome abe rration frequency revealed increased, but not significant differences between the exposed and the control populations, we conclude that the health risk among the exposed residents is similar to those among nucl ear workers. (C) 1998 Elsevier Science B.V. All rights reserved.