Area Air Samples Research Articles

Occupational exposures to new dry cleaning solvents: High-flashpoint hydrocarbons and butylal

ABSTRACTThe dry cleaning industry is moving away from using perchloroethylene. Occupational exposures to two alternative dry cleaning solvents, butylal and high-flashpoint hydrocarbons, have not been well characterized. We evaluated four dry cleaning shops that used these alternative solvents. The shops were staffed by Korean- and Cantonese-speaking owners, and Korean-, Cantonese-, and Spanish-speaking employees. Because most workers had limited English proficiency we used language services in our evaluations. In two shops we collected personal and area air samples for butylal. We also collected air samples for formaldehyde and butanol, potential hydrolysis products of butylal. Because there are no occupational exposure limits for butylal, we assessed employee health risks using control banding tools. In the remaining two shops we collected personal and area air samples for high-flashpoint hydrocarbon solvents.In all shops the highest personal airborne exposures occurred when workers loaded and unloaded the dry cleaning machines and pressed dry cleaned fabrics. The air concentrations of formaldehyde and butanol in the butylal shops were well below occupational exposure limits. Likewise, the air concentrations of high-flashpoint hydrocarbons were also well below occupational exposure limits. However, we saw potential skin exposures to these chemicals. We provided recommendations on appropriate work practices and the selection and use of personal protective equipment. These recommendations were consistent with those derived using control banding tools for butylal. However, there is insufficient toxicological and health information to determine the safety of butylal in occupational settings. Independent evaluation of the toxicological properties of these alternative dry cleaning solvents, especially butylal, is urgently needed.

Effects of a powered air-purifying respirator intervention on indium exposure reduction and indium related biomarkers among ITO sputter target manufacturing workers

This study aimed to evaluate the efficacy of powered air-purifying respirators (PAPRs) worn by the workers, and to investigate the effect of this application on exposure and preclinical effects in terms of workplace measuring and biomarker monitoring in ITO sputter target manufacturing plants and workers, respectively. Fifty-four workers were recruited and investigated from 2010–2012, during which PAPRs were provided to on-site workers in September 2011. Each worker completed questionnaires and provided blood and urine samples for analysis of biomarkers of indium exposure and preclinical effects. Area and personal indium air samples were randomly collected from selected worksites and from participants. The penetration percentage of the respirator (concentration inside respirator divided by concentration outside respirator) was 6.6%. Some biomarkers, such as S-In, SOD, GPx, GST, MDA, and TMOM, reflected the decrease in exposure and showed lower levels, after implementation of PAPRs. This study is the first to investigate the efficacy of PAPRs for reducing indium exposure. The measurement results clearly showed that the implementation of PAPRs reduces levels of indium-related biomarkers. These findings have practical applications for minimizing occupational exposure to indium and for managing the health of workers exposed to indium.

Comparison of a Wipe Method With and Without a Rinse to Recover Wall Losses in Closed Face 37-mm Cassettes used for Sampling Lead Dust Particulates

Closed-face 37-mm polystyrene cassettes are often used for exposure monitoring of metal particulates. Several methods have been proposed to account for the wall loss in air sampling cassettes, including rinsing, wiping, within-cassette dissolution, and an internal capsule fused to the filter that could be digested with the filter. Until internal capsules replace filters, other methods for assessing wall losses may be considered. To determine if rinsing and wiping or wiping alone is adequate to determine wall losses on cassettes, we collected 54 full-shift area air samples at a battery recycling facility. We collected six replicate samples at three locations within the facility for three consecutive days. The wall losses of three replicate cassettes from each day-location were analyzed following a rinse and two consecutive wipes. The wall losses of the other three replicates from each day-location were analyzed following two consecutive wipes only. Mixed-cellulose ester membrane filter, rinse, and wipes were analyzed separately following NIOSH Method 7303. We found an average of 29% (range: 8–54%) recovered lead from the cassette walls for all samples. We also found that rinsing prior to wiping the interior cassette walls did not substantially improve recovery of wall losses compared to wiping alone. A rinse plus one wipe recovered on average 23% (range: 13–33%) of the lead, while one wipe alone recovered on average 21% (range: 16–22%). Similarly, we determined that a second wipe did not provide substantial additional recovery of lead (average: 4%, range: 0.4–19%) compared to the first wipe disregarding the rinse (average: 18%, range: 4–39%). We concluded that when an internal capsule is not used, wall losses of lead dust in air sampling cassettes can be adequately recovered by wiping the internal wall surfaces of the cassette with a single wipe.

Ambient Melamine Exposure and Urinary Biomarkers of Early Renal Injury.

Information about environmental exposure to melamine and renal injury in adults is lacking. We investigated this relationship in 44 workers at two melamine tableware manufacturing factories in Taiwan (16 manufacturers, eight grinders, ten packers, and ten administrators) and 105 nonexposed workers (controls) at one shipbuilding company who were enrolled in August-December of 2012. For melamine workers, personal and area air samples were obtained at the worksite over 1 workweek (Monday-Friday). In the same week, pre- and post-shift one-spot urine samples were collected each workday and one first-spot urine sample was collected on each weekend morning and the following Monday morning. For each control, a one-spot urine sample was collected on Friday morning. A blood sample was also obtained from each participant at this time. Melamine levels were measured in air, urine, and serum, and early renal injury biomarkers were measured in urine. Urinary melamine concentrations in manufacturers increased sharply between pre- and post-shift measurements on Monday, remained significantly elevated throughout the workweek, and decreased over the weekend; changes in urinary melamine concentrations were substantially lower for other melamine workers. Manufacturers were exposed to the highest concentrations of ambient melamine and had significantly higher urinary and serum melamine concentrations than did the controls (P<0.001). Urinary melamine levels were positively associated with urinary N-acetyl β-d-glucosaminidase (NAG) levels but not microalbumin levels, and the detectable β2-microglobulin rate increased in the manufacturers group. In conclusion, ambient melamine exposure may increase the levels of urinary biomarkers of renal tubular injury in this occupational setting.

Characterization of ambient particles size in workplace of manufacturing physical fitness equipments.

The manufacturing of fitness equipment involves several processes, including the cutting and punching of iron tubes followed by welding. Welding operations produce hazardous gases and particulate matter, which can enter the alveolar, resulting in adverse health effects. This study sought to verify the particle size distribution and exposure concentrations of atmospheric air samples in various work areas of a fitness equipment manufacturing industry. Observed particle concentrations are presented by area and in terms of relative magnitude: painting (15.58 mg/m3) > automatic welding (0.66 mg/m3) > manual welding (0.53 mg/m3) > punching (0.18 mg/m3) > cutting (0.16 mg/m3). The concentrations in each of the five work areas were Cinh>Cthor>Cresp. In all areas except the painting area, extra-fine particles produced by welding at high temperatures, and further those coagulated to form larger particles. This study observed bimodal distribution in the size of welding fume in the ranges of 0.7–1 µm and 15–21 µm. Meanwhile, the mass concentrations of particles with different sizes were not consistent across work areas. In the painting area, the mass concentration was higher in Chead>Cth>Calv, but in welding areas, it was found that Calv>Chead>Cth. Particles smaller than 1µm were primarily produced by welding.

Waterpipe cafes in Baltimore, Maryland: Carbon monoxide, particulate matter, and nicotine exposure

Waterpipe smoking has been growing in popularity in the United States and worldwide. Most tobacco control regulations remain limited to cigarettes. Few studies have investigated waterpipe tobacco smoke exposures in a real world setting. We measured carbon monoxide (CO), particulate matter (PM)2.5, and airborne nicotine concentrations in seven waterpipe cafes in the greater Baltimore area. Area air samples were collected between two and five hours, with an average sampling duration of three hours. Waterpipe smoking behaviors were observed at each venue. Indoor air samplers for CO, PM2.5, and airborne nicotine were placed in the main seating area 1–2 m above the floor. Indoor airborne concentrations of PM2.5 and CO were markedly elevated in waterpipe cafes and exceeded concentrations that were observed in cigarette smoking bars. Air nicotine concentrations, although not as high as in venues that allow cigarette smoking, were markedly higher than in smoke-free bars and restaurants. Concentrations of PM approached occupational exposure limits and CO exceeded occupational exposure guidelines suggesting that worker protection measures need to be considered. This study adds to the literature indicating that both employees and patrons of waterpipe venues are at increased risk from complex exposures to secondhand waterpipe smoke.

Occupational Exposure Assessment for Engineered CaCO3 Nanoparticles

Background: Engineered nanoparticles (ENPs) are intentionally produced materials with specific properties. Emerging toxicological studies have demonstrated that exposure to ENPs could induce pulmonary diseases in animals. Little is known about the potential health effects in humans due to a lack of sufficient exposure information. To improve understanding of occupational exposure of ENPs, an exposure assessment was conducted in a CaCO3 nanoparticle manufacturing facility. Aims: The objectives of this research include characterizing job-based exposure and promoting understanding of metric suitable for nanoparticle exposure and epidemiological research. Methods: Personal and area air sampling was performed to estimate exposure of respirable dust. On-line instruments were used to measure the number concentrations and lung deposited surface area concentrations for manufacturing processes. Particle size, shape, element and degree of coagulation were assessed by SEM analysis. Results: Geometric mean of respirable mass concentrations ranged from 7.24 to 3195.86 ?g/m^3 for area sampling and 44.69 to 6023.21?g/m^3 for personal sampling. Nanoparticles dominate in the workplace, which consists of 90-98% of respirable number concentration. There are three levels of emission sources. The highest exposure of nanoparticles occurs at modification process, identified to be single emission origin. The number concentrations in nanosized range vary with the distance to this source. The second form of nanoparticle release is related to specific process, which is intermittent and sparse. In addition, combustion and welding could produce nanoparticles as well. Respirable mass is not correlated with number concentration in respirable range (r =0.0090). The number concentration in nanoscale is modestly correlated with surface area deposited in alveolar (r=0.46) and TB (r=0.66) region. Conclusions: A complete exposure characterization of nanoparticles needs to be conducted in both bulk- and nano-form. (The abstract is subject to change with added epidemiological findings.)

An exploratory study of air emissions associated with shale gas development and production in the Barnett Shale

Information regarding air emissions from shale gas extraction and production is critically important given production is occurring in highly urbanized areas across the United States. Objectives of this exploratory study were to collect ambient air samples in residential areas within 61 m (200 feet) of shale gas extraction/production and determine whether a “fingerprint” of chemicals can be associated with shale gas activity. Statistical analyses correlating fingerprint chemicals with methane, equipment, and processes of extraction/production were performed. Ambient air sampling in residential areas of shale gas extraction and production was conducted at six counties in the Dallas/Fort Worth (DFW) Metroplex from 2008 to 2010. The 39 locations tested were identified by clients that requested monitoring. Seven sites were sampled on 2 days (typically months later in another season), and two sites were sampled on 3 days, resulting in 50 sets of monitoring data. Twenty-four-hour passive samples were collected using summa canisters. Gas chromatography/mass spectrometer analysis was used to identify organic compounds present. Methane was present in concentrations above laboratory detection limits in 49 out of 50 sampling data sets. Most of the areas investigated had atmospheric methane concentrations considerably higher than reported urban background concentrations (1.8–2.0 ppmv). Other chemical constituents were found to be correlated with presence of methane. A principal components analysis (PCA) identified multivariate patterns of concentrations that potentially constitute signatures of emissions from different phases of operation at natural gas sites. The first factor identified through the PCA proved most informative. Extreme negative values were strongly and statistically associated with the presence of compressors at sample sites. The seven chemicals strongly associated with this factor (o-xylene, ethylbenzene, 1,2,4-trimethylbenzene, m- and p-xylene, 1,3,5-trimethylbenzene, toluene, and benzene) thus constitute a potential fingerprint of emissions associated with compression. Implications: Information regarding air emissions from shale gas development and production is critically important given production is now occurring in highly urbanized areas across the United States. Methane, the primary shale gas constituent, contributes substantially to climate change; other natural gas constituents are known to have adverse health effects. This study goes beyond previous Barnett Shale field studies by encompassing a wider variety of production equipment (wells, tanks, compressors, and separators) and a wider geographical region. The principal components analysis, unique to this study, provides valuable information regarding the ability to anticipate associated shale gas chemical constituents.

Isocyanate Exposure Assessment Combining Industrial Hygiene Methods with Biomonitoring for End Users of Orthopedic Casting Products

Previous studies have suggested a potential risk to healthcare workers applying isocyanate-containing casts, but the authors reached their conclusions based on immunological or clinical pulmonology test results alone. We designed a study to assess potential exposure to methylene diphenyl diisocyanate (MDI) among medical personnel applying orthopedic casts using two different application methods. Air, dermal, surface, and glove permeation sampling methods were combined with urinary biomonitoring to assess the overall risk of occupational asthma to workers handling these materials. No MDI was detected in any of the personal and area air samples obtained. No glove permeation of MDI was detected. A small proportion of surface (3/45) and dermal wipe (1/60) samples were positive for MDI, but were all from inexperienced technicians. Urinary metabolites of MDI [methylenedianiline (MDA)] were detected in three of six study participants prior to both a ‘dry’ and ‘wet’ application method, five of six after the dry method, and three of six after the wet method. All MDA results were below levels noted in worker or general populations. Our conclusion is that the risk of MDI exposure is small, but unquantifiable. Because there is some potential risk of dermal exposure, medical personnel are instructed to wear a minimum of 5-mil-thick (5 mil = 0.005 inches) nitrile gloves and avoid contact to unprotected skin. This could include gauntlets, long sleeves, and/or a laboratory coat.

Evaluation of exposures to healthcare personnel from cisplatin during a mock demonstration of intra-operative intraperitoneal chemotherapy administration

Ovarian cancer is the leading cause of death from gynecologic malignancies in the United States. In 2006, the National Cancer Institute released an announcement supporting the use of intraperitoneal (IP) chemotherapy in advanced ovarian cancer. It remains unanswered how many cycles of IP chemotherapy are required to maintain a survival advantage. There may be a benefit with as few as three IP cycles and possibly as few as one IP chemotherapy cycle. ObjectiveIn preparation for a clinical trial in which chemotherapy would be administered intra-operatively, the question of exposure to healthcare personnel arose, therefore, the purpose of this study was to perform an evaluation of healthcare personnel exposure to cisplatin during a mock demonstration of intraperitoneal chemotherapy administration. Materials and methodsThe National Institute of Occupational Safety and Health (NIOSH), the Women's Cancer Center of Nevada, and the staff of the University Medical Center, Las Vegas, participated in this mock demonstration. Employees wore personal protective equipment recommended by NIOSH. Wipe, area, and breathing zone air samples were taken from the pharmacy and operating room, and during sterilization of equipment. ResultsAll samples were negative for cisplatin, except for one surface wipe from the floor of the operating room (OR) after the mock procedure. Upon sanitization of the OR, no cisplatin was detected on the floor. ConclusionThis was the first study evaluating the exposure of healthcare personnel to the administration of cisplatin intra-operatively. NIOSH endorsed this practice so long as the employees adhere to using the recommended personal protective equipment.

Abstract 112: Transcriptomic changes in the oral mucosal epithelium reflect the physiologic response to indoor burning of solid fuels.

Abstract RATIONALE: Human exposure to indoor smoke emissions from the domestic burning of solid fuels (e.g. coal, wood, plant materials) is a major cause of morbidity and mortality that affects nearly half of the world's population. While epidemiologic studies on the health impact of indoor air pollution (IAP) have yielded valuable insights from the use of various exposure assessments (e.g. personal and area air sampling, urinary metabolites), there is a need to connect these exposure measures to biomarkers of the host's physiologic response to exposure. We have previously shown that gene-expression (GE) profiles in the upper airway epithelium are affected by tobacco smoke. Thus, we sought to determine whether transcriptomic changes in the oral mucosal epithelium might also capture physiologic responses to IAP from the burning of solid fuels. METHODS: Buccal mucosa epithelial cell scrapings were collected from healthy, non-smoking female subjects in rural Xuanwei, China, where female lung cancer rates are among the highest in the world. Benzo(a)pyrene (BaP) exposure levels from indoor burning of solid fuels (primarily coal) for cooking and heating were measured by personal in-home air monitoring. RNA from 18 samples was extracted and processed onto Affymetrix Gene 1.0 ST arrays. Student's t-test and DAVID were used to identify and characterize genes that vary between relatively high levels of BaP exposure (n=8; BaP 99.0 +/- 45.9) and low (n=10; BaP 16.2 +/- 6.1) exposure. Using GSEA, results were compared to independent airway epithelial GE profiles that distinguish current smokers from never smokers and bronchial GE profiles in subjects with and without lung cancer. RESULTS: We identified 227 genes that were differentially expressed between subjects with high and low BaP exposure (p&amp;lt;0.01). Genes elevated with high BaP exposure were enriched for genes involved in the activation of apoptosis and the Toll-Like Receptor Signaling pathway. Genes that we have previously shown to have altered expression in the bronchial, buccal, and nasal epithelium of current smokers relative to never smokers were enriched among the genes associated with BaP exposure (GSEA; q&amp;lt;0.01). There was also a significant enrichment for bronchial epithelial airway genes that were altered in subjects with and without lung cancer in a previous report (GSEA; q&amp;lt;0.01). CONCLUSION: Buccal epithelial GE is affected by BaP exposure in a population that uses coal and other solid fuels for indoor cooking and heating among healthy women in Xuanwei, China. Solid fuel emissions may elicit some of the same transcriptomic responses as cigarette smoke and lung cancer. This demonstrates the feasibility of using non-invasively collected buccal GE profiling to assess physiologic responses to other inhaled toxins such as coal smoke in population-based studies. Citation Format: Teresa W. Wang, Qing Lan, Bozena Krystyna, Nathaniel Rothman, Roberta Florido, Wei Hu, Katrina Steiling, Gang Liu, Ji Xiao, Yuriy Alekseyev, Jun Xu, Fusheng Wei, H. Dean Hosgood, Boris Reiss, George Downward, Marc Lenburg, Roel Vermeulen, Avrum Spira. Transcriptomic changes in the oral mucosal epithelium reflect the physiologic response to indoor burning of solid fuels. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 112. doi:10.1158/1538-7445.AM2013-112

Detection of Escherichia coli O157:H7 and Salmonella enterica in air and droplets at three U.S. commercial beef processing plants.

Bacteria are known to be present in the air at beef processing plants, but published data regarding the prevalences of airborne Escherichia coli O157:H7 and Salmonella enterica are very limited. To determine if airborne pathogens were present in beef processing facilities, we placed sedimentation sponges at various locations in three commercial beef plants that processed cattle from slaughter through fabrication. For the 291 slaughter area air samples, E. coli O157:H7 was isolated from 15.8% and S. enterica from 16.5%. Of the 113 evisceration area air samples, E. coli O157:H7 was isolated from only one sample and S. enterica was not isolated from any sample. Pathogens were not isolated from any of the 87 air samples from fabrication areas. Pathogen prevalences, aerobic plate counts, and Enterobacteriaceae counts were highest for air samples obtained from locations near hide removal operations. The process of hide removal disperses liquid droplets, which may contact neighboring carcasses. Samples were obtained both from hide removal locations that were close enough to hide pullers to be contacted by droplets and from locations that were not contacted by droplets. Higher pathogen prevalences, aerobic plate counts, and Enterobacteriaceae counts were observed at locations with samples contacted by the hide removal droplets. We conclude that the hide removal processes likely introduce pathogens into the air via a dispersion of liquid droplets and that these droplets may be an underappreciated source of hide-to-carcass contamination.

Asbestos Exposure among Mitering Workers

The objectives are to compare the airborne asbestos concentrations resulted from mitering of abestos cement roof sheets by a high-speed motor and a hand saw, and to monitor whether other workers near the test sites are vulnerable to the fibers exceeding the occupational exposure limit. Four test cases were carried out and altogether 7 personal and 4 area air samples were collected. The NIOSH method 7400 was employed for the air samplings and analysis. Using the phase contrast microscopy, fiber counting was conducted under Rule A. The study showed that the fiber concentration medians for personal air samples gathered from the two tools were 4.11 fibers/cc (ranged: 1.33-12.41 fibers/cc) and 0.13 fibers/cc (ranged: 0.01-5.00 fibers/cc) respectively. The median for the area samples was 0.59 fibers/cc (ranged: 0.14-3.32 fibers/cc). Comparing each study case, the concentration level caused by the high-speed motor saw was more than twice that of the hand saw. According to the area samples, the workers nearby the test site are at risk from high exposure to asbestos.

Sensitization and chronic beryllium disease at a primary manufacturing facility, part 1: historical exposure reconstruction

Previous epidemiologic studies of beryllium sensitization (BeS) and chronic beryllium disease (CBD) have reported inconsistent exposure-response relationships, likely due to exposure misclassification. The objective of this study was to develop historical estimates of size-selective personal exposure to beryllium for an epidemiologic study. In 1999, a cross-sectional survey of workers hired after 1 January 1994 was conducted at a beryllium production facility. Personal exposure data from two air sampling surveys conducted in 1999 were used to obtain total, respirable, and submicron particle baseline exposure estimates (BEE) for a job-exposure matrix (JEM). General area air samples collected from 1994-1999 were used to estimate annual changes in exposures (temporal factors) for 24 different process areas. Historical exposure estimates (HEE) were calculated by applying the temporal factors to the BEE. Workers were assigned HEE based on their work history, and their historical exposure profile was summarized as cumulative, average, or highest-ever job exposure. Changes in exposure over a 6-year period were observed in 10 of the 24 process areas with an overall mean decline of 18% per year. The overall total exposure for study participants over their work tenure ranged from: 0.001-34.44 μg/m(3)-year, 0.01-16.26 μg/m(3), and 0.01-17.54 μg /m(3) for cumulative, average, and highest-ever job, respectively. For respirable exposures, the ranges were: 0.001-15.54 μg/m(3)-year, 0.01-3.56 μg/m(3), 0.01-5.54 μg /m(3) for cumulative, average, and highest-ever job, respectively. Using this JEM, exposure-response relationships for BeS and CBD can be explored over a range of exposure metrics such as total, respirable, and submicron beryllium mass concentrations, including summary measures such as cumulative, average, or highest exposures, with the ultimate objective of elucidating a quantitative exposure-response relationship.

Occupational Exposures to Styrene Vapor in a Manufacturing Plant for Fiber-Reinforced Composite Wind Turbine Blades

A utility-scale wind turbine blade manufacturing plant requested assistance from the National Institute for Occupational Safety and Health (NIOSH) in controlling worker exposures to styrene at a plant that produced 37 and 42 m long fiber-reinforced wind turbine blades. The plant requested NIOSH assistance because previous air sampling conducted by the company indicated concerns about peak styrene concentrations when workers entered the confined space inside of the wind turbine blade. NIOSH researchers conducted two site visits and collected personal breathing zone and area air samples while workers performed the wind turbine blade manufacturing tasks of vacuum-assisted resin transfer molding (VARTM), gelcoating, glue wiping, and installing the safety platform. All samples were collected during the course of normal employee work activities and analyzed for styrene using NIOSH Method 1501. All sampling was task based since full-shift sampling from a prior Occupational Safety and Health Administration (OSHA) compliance inspection did not show any exposures to styrene above the OSHA permissible exposure limit. During the initial NIOSH site visit, 67 personal breathing zone and 18 area air samples were collected while workers performed tasks of VARTM, gelcoating, glue wipe, and installation of a safety platform. After the initial site visit, the company made changes to the glue wipe task that eliminated the need for workers to enter the confined space inside of the wind turbine blade. During the follow-up site visit, 12 personal breathing zone and 8 area air samples were collected from workers performing the modified glue wipe task. During the initial site visit, the geometric means of the personal breathing zone styrene air samples were 1.8 p.p.m. (n = 21) for workers performing the VARTM task, 68 p.p.m. (n = 5) for workers installing a safety platform, and 340 p.p.m. (n = 14) for workers performing the glue wipe task, where n is the number of workers sampled for a given mean result. Gelcoating workers included job categories of millers, gelcoat machine operators, and gelcoaters. Geometric mean personal breathing zone styrene air samples were 150 p.p.m. (n = 6) for millers, 87 p.p.m. (n = 2) for the gelcoat machine operators, and 66 p.p.m. (n = 19) for gelcoaters. The geometric mean of the personal breathing zone styrene air samples from the glue wipe task measured during the follow-up site visit was 31 p.p.m. (n = 12). The closed molding VARTM process was very effective at controlling worker exposures to styrene. Personal breathing zone styrene air samples were reduced by an order of magnitude after changes were made to the glue wipe task. The company used chemical substitution to eliminate styrene exposure during the installation of the safety platform. Recommendations were provided to reduce styrene concentrations during gelcoating.

Abstract 1876: Assessment of exposure to potential lung carcinogens in Xuanwei and Fuyuan, China: Particulate exposure from cooking and heating stoves

Abstract Residents in Xuanwei, China have the highest lung cancer incidence rates in China for both men and women, despite the fact that almost all women are non-smokers. Several lines of research have provided strong support that the excess lung cancer rate in this region is caused primarily by emissions from smoky coal exposure. We have carried out a hospital-based case-control study of non-smoking female lung cancer in Xuanwei and its neighboring county, Fuyuan, to identify which constituents of coal combustion emissions and other indoor environmental exposures are causing the high lung cancer rates in this region. In order to develop individual estimates of exposure to known or suspected lung carcinogens, we designed a comprehensive exposure assessment study of 163 households in this region to evaluate exposure to PAHs, PM2.5, silica, and other exposures from coal and wood burning. Homes that used three main fuel types (i.e., smoky coal, smokeless coal and wood), and eight stove types [e.g., firepit, fixed or portable stove, with or without ventilation] were identified and households were sampled on two consecutive days. Up to 30 households were selected for each combination of fuel and stove type. A subgroup of 53 households was measured at two time-points during the study year (e.g. summer and winter). The female head of each household was asked to wear a 24-hour personal PM2.5 air sampler at the same time that 24-hour area air sampling was employed in the main living area. Personal and area particulate matter samples (PM2.5) were collected in each home. These samples were also used to quantify particle bound PAHs including BaP (by GC/MS), elemental components (by XRF and ICP/MS), and silica (by XRD). XAD2 samples were collected for the quantification of gaseous PAHs. Other samples, including radon and organic vapor, fuel and ash were also obtained. We also collected information on potential factors that could influence exposure, such as house characteristics, stove type, fuel type and use, amount of fuel used, amount of time spent in each room. Initial analyses show that people using wood burned in firepits were exposed to the highest levels of PM2.5 measured in area (536.3±370.5 µg/m3) and personal samples(419.8±283.3 µg/m3). Burning smokeless coal in a high stove with a chimney was associated with the lowest exposure to PM2.5 (62.2±34.1 µg/m3, 62.5±29.9 µg/m3 for area and personal samples, respectively). These data show that there is a wide range of exposure to PM2.5 in this population. These data and other exposure information from this study will be used in the future to model environmental exposures and risk of lung cancer in this special, high risk population. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1876. doi:10.1158/1538-7445.AM2011-1876

Zonolite Attic Insulation Exposure Studies

Several studies were designed and conducted to evaluate amphibole asbestos exposures in homes containing Zonolite (expanded vermiculite) attic insulation (ZAI). A range of tasks selected for evaluation included cleaning, working around, moving, and removal of ZAI in attics and living spaces. The fieldwork for these studies was conducted at two homes in Spokane, WA and one home in Silver Spring, MD. Personal and area air samples were collected and analyzed as part of the exposure studies. Surface dust samples and bulk samples were also collected and analyzed. The results demonstrated that airborne concentrations of amphibole asbestos were not elevated if the material is undisturbed. The results also demonstrated that cleaning, remodeling, and other activities did produce significant concentrations of airborne amphibole asbestos when the ZAI was disturbed.

Airborne asbestos exposure during light aircraft brake replacement

Asbestos containing materials are a component of many vehicle brake systems, including those found in some light aircraft. To characterize the asbestos exposure that results from the installation and maintenance of these components, an aircraft fitted with asbestos containing brake pads had brake changes performed while both area and personal air samples were taken. The brake changing process took place in a closed, unventilated aircraft hanger and all operations were performed according to the manufacturer’s recommended procedure. Personal air samples did not detect any measurable amount of asbestos fibers during the brake changing or subsequent cleanup procedures. Analysis of personal samples ( n = 9) using phase contrast microscopy indicated airborne fiber concentrations at or below 0.003 f/ml as 8-h time weighted averages (TWAs) and less than 0.069 f/ml averaged over 28–30 min sampling periods. Airborne chrysotile fibers were detected by two area air samples with fiber concentrations remaining at or below 0.0013 f/ml over an 8-h TWA. These results indicate that normal brake changing work practices on aircraft with asbestos containing brake pads does not produce a harmful level of asbestos exposure for aircraft mechanics.

Presence of tungsten-containing fibers in tungsten refining and manufacturing processes.

In tungsten refining and manufacturing processes, a series of tungsten oxides are typically formed as intermediates in the production of tungsten powder. The present study was conducted to characterize airborne tungsten-containing fiber dimensions, elemental composition and concentrations in the US tungsten refining and manufacturing industry. During the course of normal employee work activities, seven personal breathing zone and 62 area air samples were collected and analyzed using National Institute for Occupational Safety and Health (NIOSH) fiber sampling and counting methods to determine dimensions, composition and airborne concentrations of fibers. Mixed models were used to identify relationships between potential determinants and airborne fiber concentrations. Results from transmission electron microscopy analyses indicated that airborne fibers with length >0.5 microm, diameter >0.01 microm and aspect ratios > or =3:1 were present on 35 of the 69 air samples collected. Overall, the airborne fibers detected had a geometric mean length approximately 3 microm and diameter approximately 0.3 microm. Ninety-seven percent of the airborne fibers identified were in the thoracic fraction (i.e. aerodynamic diameter < or = 10 microm). Energy dispersive X-ray spectrometry results indicated that airborne fibers prior to the carburization process consisted primarily of tungsten and oxygen, with other elements being detected in trace quantities. Based on NIOSH fiber counting 'B' rules (length > 5 microm, diameter < 3 microm and aspect ratio > or = 5:1), airborne fiber concentrations ranged from below the limit of detection to 0.085 fibers cm(-3), with calcining being associated with the highest airborne concentrations. The mixed model procedure indicated that process temperature had a marginally significant relationship to airborne fiber concentration. This finding was expected since heated processes such as calcining created the highest airborne fiber concentrations. The finding of airborne tungsten-containing fibers in this occupational setting needs to be confirmed in similar settings and demonstrates the need to obtain information on the durability and associated health effects of these fibers.

Task-Based Lead Exposures and Work Site Characteristics of Bridge Surface Preparation and Painting Contractors

This study of bridge painters working for small contractors in Massachusetts investigated the causes of elevated blood lead levels and assessed their exposure to lead. Bridge work sites were evaluated for a 2-week period during which personal and area air samples and information on work site characteristics and lead abatement methods were gathered. Short-duration personal inhalable samples collected from 18 tasks had geometric means (GM) of 3 μg/m3 to 7286 μg/m3. Full-shift, time-weighted average (TWA) inhalable samples (⩾6 hours) collected from selected workers and work sites had GMs of 2 μg/m3 to15,704 μg/m3; 80% of samples exceeded the permissible exposure limit (PEL) of 50 μg/m3, on average by a factor of 30. Area inhalable samples collected from three locations ranged from 2 μg/m3 to 40,866 μg/m3 from inside the containment, 2 μg/m3 to 471 μg/m3 from a distance of <6 meters, and 2 μg/m3 to 121 μg/m3 from >6 meters from the containment. Seventy nine percent of the area samples from inside the containment exceeded the PEL on average by a factor of 140. Through observations of work site characteristics, opportunities for improving work methods were identified, particularly the institution of engineering controls (which were only occasionally present) and improvement in the design and construction of the containment structure. The high levels of airborne lead exposures indicate a potential for serious exposure hazard for workers and environmental contamination, which can be mitigated through administrative and engineering controls. Although these data were collected over 10 years ago, a 2005 regulatory review by the Occupational Safety and Health Administration (OSHA) of its lead in construction standard reported that elevated lead exposures and blood lead levels, high occurrence of noncompliance with the lead standard, and nonimplementation of newer technology especially among small painting firms employing <10 workers are still widespread. As a result, the findings of this study are still quite germane even a decade after the introduction of the new OSHA standard.