TY - JOUR
T1 - Naturally Occurring Radioactive Materials in Coals and Coal Combustion Residuals in the United States
AU - Lauer, Nancy E.
AU - Hower, James C.
AU - Hsu-Kim, Heileen
AU - Taggart, Ross K.
AU - Vengosh, Avner
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/9/15
Y1 - 2015/9/15
N2 - The distribution and enrichment of naturally occurring radioactive materials (NORM) in coal combustion residuals (CCRs) from different coal source basins have not been fully characterized in the United States. Here we provide a systematic analysis of the occurrence of NORM (232Th, 228Ra, 238U, 226Ra, and 210Pb) in coals and associated CCRs from the Illinois, Appalachian, and Powder River Basins. Illinois CCRs had the highest total Ra (228Ra + 226Ra = 297 ± 46 Bq/kg) and the lowest 228Ra/226Ra activity ratio (0.31 ± 0.09), followed by Appalachian CCRs (283 ± 34 Bq/kg; 0.67 ± 0.09), and Powder River CCRs (213 ± 21 Bq/kg; 0.79 ± 0.10). Total Ra and 228Ra/226Ra variations in CCRs correspond to the U and Th concentrations and ash contents of their feed coals, and we show that these relationships can be used to predict total NORM concentrations in CCRs. We observed differential NORM volatility during combustion that results in 210Pb enrichment and 210Pb/226Ra ratios greater than 1 in most fly-ash samples. Overall, total NORM activities in CCRs are 7-10- and 3-5-fold higher than NORM activities in parent coals and average U.S. soil, respectively. This study lays the groundwork for future research related to the environmental and human health implications of CCR disposal and accidental release to the environment in the context of this elevated radioactivity.
AB - The distribution and enrichment of naturally occurring radioactive materials (NORM) in coal combustion residuals (CCRs) from different coal source basins have not been fully characterized in the United States. Here we provide a systematic analysis of the occurrence of NORM (232Th, 228Ra, 238U, 226Ra, and 210Pb) in coals and associated CCRs from the Illinois, Appalachian, and Powder River Basins. Illinois CCRs had the highest total Ra (228Ra + 226Ra = 297 ± 46 Bq/kg) and the lowest 228Ra/226Ra activity ratio (0.31 ± 0.09), followed by Appalachian CCRs (283 ± 34 Bq/kg; 0.67 ± 0.09), and Powder River CCRs (213 ± 21 Bq/kg; 0.79 ± 0.10). Total Ra and 228Ra/226Ra variations in CCRs correspond to the U and Th concentrations and ash contents of their feed coals, and we show that these relationships can be used to predict total NORM concentrations in CCRs. We observed differential NORM volatility during combustion that results in 210Pb enrichment and 210Pb/226Ra ratios greater than 1 in most fly-ash samples. Overall, total NORM activities in CCRs are 7-10- and 3-5-fold higher than NORM activities in parent coals and average U.S. soil, respectively. This study lays the groundwork for future research related to the environmental and human health implications of CCR disposal and accidental release to the environment in the context of this elevated radioactivity.
UR - http://www.scopus.com/inward/record.url?scp=84941662482&partnerID=8YFLogxK
U2 - 10.1021/acs.est.5b01978
DO - 10.1021/acs.est.5b01978
M3 - Article
C2 - 26328894
AN - SCOPUS:84941662482
SN - 0013-936X
VL - 49
SP - 11227
EP - 11233
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 18
ER -
