title: Ambient monitoring of airborne radioactivity near a former thorium processing plant.
abstract: Twenty-four hour sampling for airborne radioactivity near a former thorium and rare-earth extraction facility was conducted for approx. 2 months with high-volume and dichotomous air samplers. Thoron ( 220Rn ) daughters were identified in the air and confirmed to be originating from the waste storage site. High-volume samplers near the facility measured average 212Pb concentrations of 177, 43, and 237 pCi/m3 with corresponding ranges of (1.9-1351), (1.5-301) and (0.73-2201)pCi/m3. Simultaneous measurements with dichotomous samplers at the same sites measured average 212Pb concentrations on coarse particulates (2.5-15 microns dia.) of 14, 4 and 10 pCi/m3 and on fine particulates (less than 2.5 microns dia.) of 94, 9 and 214 pCi/m3, respectively. Corresponding ranges were (0.2-109), (0.1-63) and (0.1-94) pCi/m3 for coarse particulates and (0.7-1094), (0.4-101) and (0.5-2685) pCi/m3 for fine particulates. Uranium, thorium and radium radionuclides were not identified as being present in significant concentrations in the particulate samples.
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000396:Air Pollutants, Radioactive / Q000032:analysis*; D001729:Bismuth / Q000032:analysis; D007854:Lead / Q000032:analysis; D011059:Polonium / Q000032:analysis; D011834:Radiation Monitoring; D011850:Radioactive Waste; D017687:Radon Daughters; D013910:Thorium
chemical_list: D000393:Air Pollutants; D000396:Air Pollutants, Radioactive; D011850:Radioactive Waste; D017687:Radon Daughters; D007854:Lead; D013910:Thorium; D011059:Polonium; D001729:Bismuth