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Airborne crystalline silica concentrations at coal-fired power plants associated with coal fly ash.
J Occup Environ Hyg. 2006 Aug; 3(8):448-55.JO

Abstract

This study presents measurements of airborne concentrations of respirable crystalline silica in the breathing zone of workers who were anticipated to encounter coal fly ash. Six plants were studied; two were fired with lignite coal, and the remaining four plants used bituminous and subbituminous coals. A total of 108 personal breathing zone respirable dust air samples were collected. Bulk samples were also collected from each plant site and subjected to crystalline silica analysis. Airborne dust particle size analysis was measured where fly ash was routinely encountered. The results from bituminous and subbituminous fired plants revealed that the highest airborne fly ash concentrations are encountered during maintenance activities: 0.008 mg/m3 to 96 mg/m3 (mean of 1.8 mg/m3). This group exceeded the threshold limit values (TLV) in 60% of the air samples. During normal production activities, airborne concentrations of crystalline silica ranged from nondetectable to 0.18 mg/m3 (mean value of 0.048 mg/m3). Air samples collected during these activities exceeded the current and proposed TLVs in approximately 54% and 65% of samples, respectively. Limited amounts of crystalline silica were detected in samples collected from lignite-fired plants, and approximately 20% of these air samples exceeded the current TLV. Particle size analysis in areas where breathing zone air samples were collected revealed mass median diameters typically between 3 microm and 8 microm. Bulk and air samples were analyzed for all of the common crystalline silica polymorphs, and only alpha quartz was detected. As compared with air samples, bulk samples from the same work areas consistently yielded lower relative amounts of quartz. Controls to limit coal fly ash exposures are indicated during some normal plant operations and during episodes of short term, but high concentrations of dust that may be encountered during maintenance activities, especially in areas where ash accumulations are present.

Authors+Show Affiliations

Exponent Inc., 1970 Broadway, Oakland, CA 94612, USA. jhicks@exponent.comNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

16862716

Citation

Hicks, Jeffrey, and Janice Yager. "Airborne Crystalline Silica Concentrations at Coal-fired Power Plants Associated With Coal Fly Ash." Journal of Occupational and Environmental Hygiene, vol. 3, no. 8, 2006, pp. 448-55.
Hicks J, Yager J. Airborne crystalline silica concentrations at coal-fired power plants associated with coal fly ash. J Occup Environ Hyg. 2006;3(8):448-55.
Hicks, J., & Yager, J. (2006). Airborne crystalline silica concentrations at coal-fired power plants associated with coal fly ash. Journal of Occupational and Environmental Hygiene, 3(8), 448-55.
Hicks J, Yager J. Airborne Crystalline Silica Concentrations at Coal-fired Power Plants Associated With Coal Fly Ash. J Occup Environ Hyg. 2006;3(8):448-55. PubMed PMID: 16862716.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Airborne crystalline silica concentrations at coal-fired power plants associated with coal fly ash. AU - Hicks,Jeffrey, AU - Yager,Janice, PY - 2006/7/26/pubmed PY - 2006/11/15/medline PY - 2006/7/26/entrez SP - 448 EP - 55 JF - Journal of occupational and environmental hygiene JO - J Occup Environ Hyg VL - 3 IS - 8 N2 - This study presents measurements of airborne concentrations of respirable crystalline silica in the breathing zone of workers who were anticipated to encounter coal fly ash. Six plants were studied; two were fired with lignite coal, and the remaining four plants used bituminous and subbituminous coals. A total of 108 personal breathing zone respirable dust air samples were collected. Bulk samples were also collected from each plant site and subjected to crystalline silica analysis. Airborne dust particle size analysis was measured where fly ash was routinely encountered. The results from bituminous and subbituminous fired plants revealed that the highest airborne fly ash concentrations are encountered during maintenance activities: 0.008 mg/m3 to 96 mg/m3 (mean of 1.8 mg/m3). This group exceeded the threshold limit values (TLV) in 60% of the air samples. During normal production activities, airborne concentrations of crystalline silica ranged from nondetectable to 0.18 mg/m3 (mean value of 0.048 mg/m3). Air samples collected during these activities exceeded the current and proposed TLVs in approximately 54% and 65% of samples, respectively. Limited amounts of crystalline silica were detected in samples collected from lignite-fired plants, and approximately 20% of these air samples exceeded the current TLV. Particle size analysis in areas where breathing zone air samples were collected revealed mass median diameters typically between 3 microm and 8 microm. Bulk and air samples were analyzed for all of the common crystalline silica polymorphs, and only alpha quartz was detected. As compared with air samples, bulk samples from the same work areas consistently yielded lower relative amounts of quartz. Controls to limit coal fly ash exposures are indicated during some normal plant operations and during episodes of short term, but high concentrations of dust that may be encountered during maintenance activities, especially in areas where ash accumulations are present. SN - 1545-9624 UR - https://www.unboundmedicine.com/medline/citation/16862716/Airborne_crystalline_silica_concentrations_at_coal_fired_power_plants_associated_with_coal_fly_ash_ DB - PRIME DP - Unbound Medicine ER -