Annals of Occupational Hygiene - recent issues

Proposed British-Dutch Guidance on Measuring Compliance with Occupational Exposure Limits

Ogden, T. L. — Tue, 10 Nov 2009 08:12:12 PST

Oxygen Depletion and Formation of Toxic Gases following Sea Transportation of Logs and Wood Chips

Svedberg, U., Petrini, C., Johanson, G. — Tue, 10 Nov 2009 08:12:12 PST

Several recent accidents with fatal outcomes occurring during discharge of logs and wood chips from ships in Swedish ports indicate the need to better understand the atmospheric conditions in holds and connecting stairways. The principal aim of the present study was to assess the air levels of oxygen and toxic gases in confined spaces following sea transportation of logs and wood chips. The focus of the study was the conditions in the stairways, as this was the location of the reported accidents. Forty-one shipments of logs (pulpwood) and wood chips carried by 10 different ships were investigated before discharge in ports in northern Sweden. A full year was covered to accommodate variations due to seasonal temperature changes. The time from completion of loading to discharge was estimated to be 37–66 h (mean 46 h). Air samples were collected in the undisturbed air of altogether 76 stairways before the hatch covers were removed. The oxygen level was measured on-site by handheld direct-reading multi-gas monitors. On 16 of the shipments, air samples were additionally collected in Tedlar® bags for later analysis for carbon dioxide, carbon monoxide, and hydrocarbons by fourier transform infrared spectroscopy. The mean oxygen level was 10% (n = 76) but in 17% of the samples the oxygen level was 0%. The oxygen depletion was less pronounced during the cold season. The mean CO2 and CO levels were 7.5% (n = 26) and 46 p.p.m. (n = 28), respectively. More than 90% of the hydrocarbons were explained by monoterpenes, mainly -pinene (mean 41 p.p.m., (n = 26). In conclusion, the measurements show that transport of logs and wood chips in confined spaces may result in rapid and severe oxygen depletion and CO₂ formation. Thus, apparently harmless cargoes may create potentially life-threatening conditions. The oxygen depletion and CO₂ formation are seemingly primarily caused by microbiological activity, in contrast to the oxidative processes with higher CO formation that predominate in cargoes of wood pellets. Improved technical and organizational measures are considered necessary to prevent future accidents. Recommendations given regarding safe entry procedures and technical preventive methods may also apply to other oxygen-depleting products.

Rate and Peak Concentrations of Off-Gas Emissions in Stored Wood Pellets--Sensitivities to Temperature, Relative Humidity, and Headspace Volume

Kuang, X., Shankar, T. J., Bi, X. T., Lim, C. J., Sokhansanj, S., Melin, S. — Tue, 10 Nov 2009 08:12:12 PST

Wood pellets emit CO, CO₂, CH₄, and other volatiles during storage. Increased concentration of these gases in a sealed storage causes depletion of concentration of oxygen. The storage environment becomes toxic to those who operate in and around these storages. The objective of this study was to investigate the effects of temperature, moisture, and the relative size of storage headspace on emissions from wood pellets in an enclosed space. Twelve 10-l plastic containers were used to study the effects of headspace ratio (25, 50, and 75% of container volume) and temperatures (10–50°C). Another eight containers were set in uncontrolled storage relative humidity (RH) and temperature. Concentrations of CO₂, CO, and CH₄ were measured by gas chromatography (GC). The results showed that emissions of CO₂, CO, and CH₄ from stored wood pellets are more sensitive to storage temperature than to RH and the relative volume of headspace. Higher peak emission factors are associated with higher temperatures. Increased headspace volume ratio increases peak off-gas emissions because of the availability of oxygen associated with pellet decomposition. Increased RH in the enclosed container increases the rate of off-gas emissions of CO₂, CO, and CH₄ and oxygen depletion.

Emission of Volatile Aldehydes and Ketones from Wood Pellets under Controlled Conditions

Arshadi, M., Geladi, P., Gref, R., Fjallstrom, P. — Tue, 10 Nov 2009 08:12:12 PST

Different qualities of biofuel pellets were made from pine and spruce sawdust according to an industrial experimental design. The fatty/resin acid compositions were determined by gas chromatography-mass spectrometry for both newly produced pellets and those after 2 and 4 weeks of storage. The aldehydes/ketones compositions were determined by high performance liquid chromatography at 0, 2, and 4 weeks. The designs were analyzed for the response variables: total fatty/resin acids and total aldehydes/ketones. The design showed a strong correlation between the pine fraction in the pellets and the fatty/resin acid content but the influence decreased over storage time. The amount of fatty/resin acids decreased ~40% during 4 weeks. The influence of drying temperature on the aldehyde/ketone emission of fresh pellets was also shown. The amounts of emitted aldehydes/ketones generally decreased by 45% during storage as a consequence of fatty/resin acid oxidation. The matrices of individual concentrations were subjected to multivariate data analysis. This showed clustering of the different experimental runs and demonstrated the important mechanism of fatty/resin acid conversion.

Effects of Headspace and Oxygen Level on Off-gas Emissions from Wood Pellets in Storage

Kuang, X., Shankar, T. J., Sokhansanj, S., Lim, C. J., Bi, X. T., Melin, S. — Tue, 10 Nov 2009 08:12:12 PST

Few papers have been published in the open literature on the emissions from biomass fuels, including wood pellets, during the storage and transportation and their potential health impacts. The purpose of this study is to provide data on the concentrations, emission factors, and emission rate factors of CO₂, CO, and CH₄ from wood pellets stored with different headspace to container volume ratios with different initial oxygen levels, in order to develop methods to reduce the toxic off-gas emissions and accumulation in storage spaces. Metal containers (45 l, 305 mm diameter by 610 mm long) were used to study the effect of headspace and oxygen levels on the off-gas emissions from wood pellets. Concentrations of CO₂, CO, and CH₄ in the headspace were measured using a gas chromatograph as a function of storage time. The results showed that the ratio of the headspace ratios and initial oxygen levels in the storage space significantly affected the off-gas emissions from wood pellets stored in a sealed container. Higher peak emission factors and higher emission rates are associated with higher headspace ratios. Lower emissions of CO₂ and CO were generated at room temperature under lower oxygen levels, whereas CH₄ emission is insensitive to the oxygen level. Replacing oxygen with inert gases in the storage space is thus a potentially effective method to reduce the biomass degradation and toxic off-gas emissions. The proper ventilation of the storage space can also be used to maintain a high oxygen level and low concentrations of toxic off-gassing compounds in the storage space, which is especially useful during the loading and unloading operations to control the hazards associated with the storage and transportation of wood pellets.

Evaluation of Five Decontamination Methods for Filtering Facepiece Respirators

Viscusi, D. J., Bergman, M. S., Eimer, B. C., Shaffer, R. E. — Tue, 10 Nov 2009 08:12:12 PST

Concerns have been raised regarding the availability of National Institute for Occupational Safety and Health (NIOSH)-certified N95 filtering facepiece respirators (FFRs) during an influenza pandemic. One possible strategy to mitigate a respirator shortage is to reuse FFRs following a biological decontamination process to render infectious material on the FFR inactive. However, little data exist on the effects of decontamination methods on respirator integrity and performance. This study evaluated five decontamination methods [ultraviolet germicidal irradiation (UVGI), ethylene oxide, vaporized hydrogen peroxide (VHP), microwave oven irradiation, and bleach] using nine models of NIOSH-certified respirators (three models each of N95 FFRs, surgical N95 respirators, and P100 FFRs) to determine which methods should be considered for future research studies. Following treatment by each decontamination method, the FFRs were evaluated for changes in physical appearance, odor, and laboratory performance (filter aerosol penetration and filter airflow resistance). Additional experiments (dry heat laboratory oven exposures, off-gassing, and FFR hydrophobicity) were subsequently conducted to better understand material properties and possible health risks to the respirator user following decontamination. However, this study did not assess the efficiency of the decontamination methods to inactivate viable microorganisms. Microwave oven irradiation melted samples from two FFR models. The remainder of the FFR samples that had been decontaminated had expected levels of filter aerosol penetration and filter airflow resistance. The scent of bleach remained noticeable following overnight drying and low levels of chlorine gas were found to off-gas from bleach-decontaminated FFRs when rehydrated with deionized water. UVGI, ethylene oxide (EtO), and VHP were found to be the most promising decontamination methods; however, concerns remain about the throughput capabilities for EtO and VHP. Further research is needed before any specific decontamination methods can be recommended.

Particle Emission and Exposure during Nanoparticle Synthesis in Research Laboratories

Demou, E., Stark, W. J., Hellweg, S. — Tue, 10 Nov 2009 08:12:12 PST

Real-time size, mass and number particle concentrations, and emission rates in university laboratories producing nanoparticles by scalable flame spray pyrolysis are quantified. Measurements were conducted in four laboratories using various technological set-ups and during production of particles of a range of compositions with differing physical–chemical properties, from NaCl salt, BiPO₄, CaSO₄, Bi₂O₃, insoluble TiO₂, SiO₂, and WO₃ to composites such as Cu/ZnO, Cu/SiO₂, Cu/ZrO₂, Ta₂O₅/SiO₂, and Pt/Ba/Al₂O₃. Production time ranged from 0.25 to 400 min and yields from 0.33 to 183 g. Temporal and spatial analyses of the particle concentrations were performed indicating that elevated number concentrations in the workplace can occur. Airborne submicron number concentrations increased from background levels of 2100 up to 106 000 cm^–3 during production, while the mass concentration ranged from a background of 0.009 to 0.463 mg m^–3. Maximum particle number emission rates amounted to 1.17 x 10¹² min^–1. The size distributions displayed concentration peaks mainly between 110 and 180 nm. However, changes in the operating conditions and the production of certain nanoparticles resulted in concentration peaks in the nanoparticle size range <100 nm. The effectiveness and limitations of current technology in assessing researchers’ exposure to nanoparticles during production are examined, and further measures for workers’ protection are proposed.

Airborne Asbestos Concentrations Associated with Heavy Equipment Brake Removal

Madl, A. K., Gaffney, S. H., Balzer, J. L., Paustenbach, D. J. — Tue, 10 Nov 2009 08:12:12 PST

Asbestos-containing brake linings were used in heavy-duty construction equipment such as tractors, backhoes, and bulldozers prior to the 1980s. While several published studies have evaluated exposures to mechanics during brake repair work, most have focused on automobiles and light trucks, not on heavy agricultural or construction vehicles. The purpose of this study is to characterize the airborne concentration of asbestos to workers and bystanders from brake wear debris during brake removal from 12 loader/backhoes and tractors manufactured between 1960 and 1980. Asbestos content in brake lining (average 20% chrysotile by polarized light microscopy) and brake wear debris [average 0.49% chrysotile by transmission electron microscopy (TEM)] was also quantified. Breathing zone samples on the lapel of mechanics (n = 44) and area samples at bystander (n = 34), remote (n = 22), and ambient (n = 12) locations were collected during 12 brake changes and analyzed using phase contrast microscopy (PCM) [National Institute for Occupational Safety and Health (NIOSH) 7400] and TEM (NIOSH 7402). In addition, the fiber distribution by size and morphology was evaluated according to the International Organization for Standardization method for asbestos. Applying the ratio of asbestos fibers:total fibers (including non-asbestos) as determined by TEM to the PCM results, the average airborne chrysotile concentrations (PCM equivalent) were 0.024 f/cc for the mechanic and 0.009 f/cc for persons standing 1.2–3.1 m from the activity during the period of exposure (~0.5 to 1 h). Considering the time involved in the activity, and assuming three brake jobs per shift, these results would convert to an average 8-h time-weighted average of 0.009 f/cc for a mechanic and 0.006 f/cc for a bystander. The results indicate that (i) the airborne concentrations for worker and bystander samples were significantly less than the current occupational exposure limit of 0.1 f/cc; (ii) ~2% of respirable fibers were >20 µm in length; and (iii) ~95% of chrysotile in the brake linings degraded in the friction process. The industrial hygiene data presented here should be useful for conducting retrospective and current exposure assessments of individuals, as well as hazard assessments of work activities that involve repairing and replacing asbestos-containing brakes in heavy construction equipment.

Direct Detection of Salmonella Cells in the Air of Livestock Stables by Real-Time PCR

Fallschissel, K., Kampfer, P., Jackel, U. — Tue, 10 Nov 2009 08:12:12 PST

A SYBR^® Green real-time quantitative polymerase chain reaction (qPCR) assay for specific detection and quantification of airborne Salmonella cells in livestock housings is presented. A set of specific primers was tested and validated for specific detection and quantification of Salmonella-specific invA genes of DNA extracted from bioaerosol samples. Application of the method to poultry house bioaerosol samples showed concentrations ranging from 2.2 x 10¹ to 3 x 10⁶ Salmonella targets m^–3 of air. Salmonella were also detected by a cultivation-based approach in some samples, but concentrations were two to three magnitudes lower than the concentrations detected by molecular biological results. Specificity of results was demonstrated by cloning analyses of PCR products, which were exclusively assigned to the genus Salmonella. However, by molecular methods, microorganisms are detected independently of their viability status, leading to an overestimation of concentration. Hence, the survival rate of Salmonella cells was measured on filter surfaces during filtration samplings where 82% of the cells died within 20 min of filtration. The results clearly show the specificity and practicability of the established qPCR assay for analysis and quantification of salmonellae in bioaerosols. The results demonstrate airborne Salmonella workplace concentrations in poultry production of up to 3.3% of 4',6-Diamidino-2-phenylindole-counted total cell numbers.

Data Sharing, Federal Rule of Evidence 702, and the Lions in the Undergrowth

Ogden, T. — Wed, 07 Oct 2009 07:13:10 PDT

Many concerns would find it useful to have a publicly available database recording exposures to particular substances, with contextual information. The European Union's Registration, Evaluations, Authorisation, and restriction of Chemicals regulation has increased interest in this. It has been suggested that journals should require detailed publication of exposure data with papers. But there are problems for researchers, for whom the data are a valuable resource which has been obtained with effort and often ingenuity. The publication could also raise problems of confidentiality and liability, and those who have to put the effort in publication are not those who benefit. Also, there are the problems of hostile critics misusing the information—for example, industry reanalysing data to counter any regulatory implications of a study—and this raises serious wider issues of editorial policy. Two books have recently given examples of industry misuse of science, ‘Doubt is their product’ by David Michaels and ‘Defending the indefensible’ by McCullogh and Tweedale. Michaels gives examples of hostile data reanalysis, and among other things, he discusses the impact on journals of US Federal Rule of Evidence 702, which encourages expert witnesses to try to get their testimony material into peer-reviewed journals. This certainly lies behind some submissions to this journal, and Michaels says that it has led to the creation of peer-reviewed journals which have strong industry influence. On the other hand, work funded by industry is not always wrong, papers from other sources are not always free from bias, and the problem for journals is to continue to apply consistent scientific standards in a sea of conflicting interests. It does not seem feasible or desirable for journals to insist on the publication of all the underlying data, although researchers might be encouraged to form consortia to share data.

Trends in Wood Dust Inhalation Exposure in the UK, 1985-2005

Wed, 07 Oct 2009 07:13:11 PDT

Objectives: Wood dust data held in the Health and Safety Executive (HSE) National Exposure DataBase (NEDB) were reviewed to investigate the long-term changes in inhalation exposure from 1985 to 2005. In addition, follow-up sampling measurements were obtained from selected companies where exposure measurements had been collected prior to 1994, thereby providing a follow-up period of at least 10 years, to determine whether changes in exposure levels had occurred, with key staff being interviewed to identify factors that might be responsible for any changes observed.

Methods: Analysis of the temporal trend in exposure concentrations was performed using Linear Mixed Effect Models on the log-transformed NEDB data set and expressed as the relative annual change in concentration.

Results: For the NEDB wood dust data, an annual decline of geometric mean (GM) exposure of 8.1% per year was found based on 1459 exposure measurements collected between 1985 and 2003. This trend was predominantly observed in data from inspection visits (measurements collected on a mandatory basis by a Specialist HSE Inspector) (n = 1009), while data from representative surveys (measurements collected on a voluntary basis to provide information on current practices and exposures) remained relatively stable. Ten follow-up surveys in individual workplaces in 2004–2005 resulted in 70 new measurements and for each of the companies resurveyed, the GM of the wood dust exposure decreased between sampling surveys.

Conclusion: Analysis of the temporal trend in UK wood dust exposure concentrations revealed declines of 8% per annum. Interviews with key long-serving employees and management suggest that factors such as technological changes in production processes, response to new legislation, and enforcement agency inspections, together with global economic trends, could be linked to the downward trends observed.

Beryllium Decontamination with Different Solvents on Different Structures

Dufresne, A., Dion, C., Viau, S., Perrault, G. — Wed, 07 Oct 2009 07:13:11 PDT

The objective of the present work was to estimate the efficiency of moistened wipes in removing beryllium with different solutions including Citranox^TM, Alconox^TM, NaCl 5%, Resolve^TM, and Ledizolv^TM on various types of surfaces such as unpainted metal, wood frames, painted metal, concrete, painted concrete, and Plexiglas^TM from three different occupational settings. Of the three plants that were investigated, only surfaces in the aluminium smelter were decontaminated down to the clearance reference level of 0.2 µg 100 cm^–2, with all the solvents used. In the machine tooling and milling department, the clearance level of 0.2 µg 100 cm^–2 was reached after the three decontaminations, with all the solvents. In the machine plant for the military, aerospace, and telecommunications industries, the beryllium concentrations on the concrete wall, before decontamination with the high-pressure gun, were usually >3 µg 100 cm^–2, and concentrations as high as 31 µg 100 cm^–2 were measured. After the high-pressure cleanup, the beryllium concentrations were sometimes reduced by a factor of 10, but never reached the clearance level. Beryllium compounds that had adhered to most types of structures that we attempted to decontaminate were reduced to below the clearance reference value except on concrete floors. There did not seem to be any difference between the decontamination actions for all the solvents used in this study.

Quantification and Statistical Modeling--Part I: Breathing-Zone Concentrations of Monomeric and Polymeric 1,6-Hexamethylene Diisocyanate

Wed, 07 Oct 2009 07:13:11 PDT

We conducted a repeated exposure-assessment survey for task-based breathing-zone concentrations (BZCs) of monomeric and polymeric 1,6-hexamethylene diisocyanate (HDI) during spray painting on 47 automotive spray painters from North Carolina and Washington State. We report here the use of linear mixed modeling to identify the primary determinants of the measured BZCs. Both one-stage (N = 98 paint tasks) and two-stage (N = 198 paint tasks) filter sampling was used to measure concentrations of HDI, uretidone, biuret, and isocyanurate. The geometric mean (GM) level of isocyanurate (1410 µg m^–3) was higher than all other analytes (i.e. GM < 7.85 µg m^–3). The mixed models were unique to each analyte and included factors such as analyte-specific paint concentration, airflow in the paint booth, and sampler type. The effect of sampler type was corroborated by side-by-side one- and two-stage personal air sampling (N = 16 paint tasks). According to paired t-tests, significantly higher concentrations of HDI (P = 0.0363) and isocyanurate (P = 0.0035) were measured using one-stage samplers. Marginal R² statistics were calculated for each model; significant fixed effects were able to describe 25, 52, 54, and 20% of the variability in BZCs of HDI, uretidone, biuret, and isocyanurate, respectively. Mixed models developed in this study characterize the processes governing individual polyisocyanate BZCs. In addition, the mixed models identify ways to reduce polyisocyanate BZCs and, hence, protect painters from potential adverse health effects.

Quantification and Statistical Modeling--Part II: Dermal Concentrations of Monomeric and Polymeric 1,6-Hexamethylene Diisocyanate

Wed, 07 Oct 2009 07:13:11 PDT

We conducted a quantitative dermal and inhalation exposure assessment of monomeric and polymeric 1,6-hexamethylene diisocyanates (HDI) in 47 automotive spray painters from North Carolina and Washington State. We report here the use of linear mixed modeling (LMM) to identify the primary determinants of dermal exposure. Dermal concentrations of HDI, uretidone, biuret, and isocyanurate were significantly higher in 15 painters who did not wear coveralls or gloves (N = 51 paint tasks) than in 32 painters who did wear coveralls and gloves (N = 192 paint tasks) during spray painting. Regardless of whether protective clothing was worn, isocyanurate was the predominant species measured in the skin [geometric mean (GM) = 33.8 ng mm^–3], with a 95% detection rate. Other polyisocyanates (GM ≤ 0.17 ng mm^–3) were detected in skin during <23% of the paint tasks. According to marginal R² statistics, mixed models generated in this study described no <36% of the variability in dermal concentrations of the different polyisocyanates measured in painters who did not wear protective clothing. These models also described 55% of the variability in dermal concentrations of isocyanurate measured in all painters (N = 288 paint tasks). The product of analyte-specific breathing-zone concentration (BZC) and paint time was the most significant variable in all the models. Through LMM, a better understanding of the exposure pathways governing individual polyisocyanate exposures may be achieved. In particular, we were able to establish a link between BZC and dermal concentration, which may be useful for exposure reconstruction and quantitatively characterizing the protective effect of coveralls and gloves. This information can be used to reduce dermal exposures and better protect automotive spray painters from potential adverse health effects.

Guidance Values for Surface Monitoring of Antineoplastic Drugs in German Pharmacies

Schierl, R., Bohlandt, A., Nowak, D. — Wed, 07 Oct 2009 07:13:11 PDT

Objectives: Antineoplastic drugs are widely used in anticancer therapy due to their cytotoxic activity but many of them are classified as carcinogenic, mutagenic, or teratogenic to humans. In order to evaluate personal exposure, surface monitoring has been successfully applied for several years. In this study, we present a statistical description of our data set from 102 German pharmacies and propose ‘threshold guidance values (TGVs)’ to facilitate interpretation of monitoring results.

Methods: Our database included 1008 results for platinum (PT) and 1237 for 5-fluorouracil (FU) collected in 102 pharmacies in Germany. Wipe sampling on site was performed with one validated procedure. PT concentrations were measured by voltammetry and FU by gas chromatography/mass spectrometry. Data were stratified into 10 locations and statistically evaluated.

Results: Contamination was detected on all surfaces in the pharmacies with high levels on storage shelves and floors. The median values for the different locations ranged from 0.20 to 1.70 pg cm^–2 (mean: 0.57 pg cm^–2) for PT and from 2.50 to 10.00 pg cm^–2 (mean: 5.34 pg cm^–2) for FU. The mean 75th percentiles were 3.92 pg cm^–2 (PT) and 28.90 pg cm^–2 (FU). The TGV 1 value was set at the median value and results below demonstrate good working practices. Contaminations above the TGV 2, which was assigned at the 75th percentile, show a clear need for optimizing the handling procedures.

Conclusions: The introduction of TGVs helps to reduce occupational exposure and allows pharmacy personnel to benchmark their own contamination levels. This provides a basis for improvement in occupational safety precautions and for regular contamination controls.

Recombinant Factor C (rFC) Assay and Gas Chromatography/Mass Spectrometry (GC/MS) Analysis of Endotoxin Variability in Four Agricultural Dusts

Wed, 07 Oct 2009 07:13:11 PDT

Endotoxin exposure is a significant concern in agricultural environments due to relatively high exposure levels. The goals of this study were to determine patterns of 3-hydroxy fatty acid (3-OHFA) distribution in dusts from four types of agricultural environments (dairy, cattle feedlot, grain elevator, and corn farm) and to evaluate correlations between the results of gas chromatography/mass spectrometry (GC/MS) analysis (total endotoxin) and biological recombinant factor C (rFC) assay (free bioactive endotoxin). An existing GC/MS-MS method (for house dust) was modified to reduce sample handling and optimized for small amount (<1 mg) of agricultural dusts using GC/EI-MS. A total of 134 breathing zone samples using Institute of Occupational Medicine (IOM) inhalable samplers were collected from agricultural workers in Colorado and Nebraska. Livestock dusts contained approximately two times higher concentrations of 3-OHFAs than grain dusts. Patterns of 3-OHFA distribution and proportion of each individual 3-OHFA varied by dust type. The rank order of Pearson correlations between the biological rFC assay and the modified GC/EI-MS results was feedlot (0.72) > dairy (0.53) > corn farm (0.33) > grain elevator (0.11). In livestock environments, both odd- and even-numbered carbon chain length 3-OHFAs correlated with rFC assay response. The GC/EI-MS method should be especially useful for identification of specific 3-OHFAs for endotoxins from various agricultural environments and may provide useful information for evaluating the relationship between bacterial exposure and respiratory disease among agricultural workers.

Exposure to Polycyclic Aromatic Hydrocarbons (PAHs), Mutagenic Aldehydes, and Particulate Matter in Norwegian a la Carte Restaurants

Sjaastad, A. K., Svendsen, K. — Wed, 07 Oct 2009 07:13:11 PDT

Objectives: The aim of the study was to characterize the exposure regarding polycyclic aromatic hydrocarbons (PAHs) and higher mutagenic aldehydes in the breathing zone of the cook during work in Norwegian à la carte restaurants. Levels of particle exposure were also measured to make the results comparable to other studies.

Methods: Personal measurements of the levels of PAHs, higher aldehydes, and total particles were performed in three restaurants in the city of Trondheim in the middle of Norway.

Results: Naphthalene was detected within the range of 0.05–0.27 µg m^–3 air, and the total mean value for all three restaurants was 0.18 µg m^–3 air. The measured levels of mutagenic aldehydes were between 1.03 and 17.67 µg m^–3 air. The mean mass concentration of total particles measured in the three restaurants was 1.93 mg m^–3, and the levels registered were within the range 0.32–7.51 mg m^–3.

Conclusions: Working as a cook in a Norwegian à la carte restaurant with some manual panfrying involves exposure to components in cooking fumes which may cause adverse health effects. Additional studies are necessary in order to identify relations between exposure levels and the adverse health effects of cooking fumes.

Development of a Sampler for Total Aerosol Deposition in the Human Respiratory Tract

Koehler, K. A., Clark, P., Volckens, J. — Wed, 07 Oct 2009 07:13:11 PDT

Studies that seek to associate reduced human health with exposure to occupational and environmental aerosols are often hampered by limitations in the exposure assessment process. One limitation involves the measured exposure metric itself. Current methods for personal exposure assessment are designed to estimate the aspiration of aerosol into the human body. Since a large proportion of inhaled aerosol is subsequently exhaled, a portion of the aspirated aerosol will not contribute to the dose. This leads to variable exposure misclassification (for heterogenous exposures) and increased uncertainty in health effect associations. Alternatively, a metric for respiratory deposition would provide a more physiologically relevant estimate of risk. To address this challenge, we have developed a method to estimate the deposition of aerosol in the human respiratory tract using a sampler engineered from polyurethane foam. Using a semi-empirical model based on inertial, gravitational, and diffusional particle deposition, a foam was engineered to mimic aerosol total deposition in the human respiratory tract. The sampler is comprised of commercially available foam with fiber diameter = 49.5 µm (equivalent to industry standard 100 PPI foam) of 8 cm thickness operating at a face velocity of 1.3 m s^–1. Additionally, the foam sampler yields a relatively low-pressure drop, independent of aerosol loading, providing uniform particle collection efficiency over time.

Experimental Characterization of a Plume of Passive Contaminant above a Thermal Source: Capture Efficiency of a Fume Extraction Hood

Devienne, R., Fontaine, J. R., Kicka, J., Bonthoux, F. — Wed, 07 Oct 2009 07:13:11 PDT

Industrial ventilation problems can be linked to the formation of thermal plumes that develop due to natural convection above various heat sources. These plumes, independent of the energy losses and thermal constraints caused, can also be the carrier of polluting products. This article describes an experimental study of the dynamic, thermal, and mass fields that develop from a hot rectangular (0.5 x 1.25 m) horizontal source. The metrology available allows the measurement of not only the local temperatures and velocities but also the concentration of a tracer gas (helium). Mathematical models have been developed enabling representation of the fields concerned; their characterization by isothermal, iso-velocity, or iso-concentration curves; calculation of the flow rate carried by the plume at a given height; calculation of the enthalpy transport; and so on. Moreover, a pollutant capture device has been introduced, and the measurement technique used allows the determination of various efficiencies of practical interest. The ratio of capture flow to free plume flow at a particular height appears to correlate well with the mean efficiencies obtained for distinct source temperatures.

Airborne Fungal and Bacterial Components in PM1 Dust from Biofuel Plants

Madsen, A. M., Schlunssen, V., Olsen, T., Sigsgaard, T., Avci, H. — Wed, 07 Oct 2009 07:13:11 PDT

Fungi grown in pure cultures produce DNA- or RNA-containing particles smaller than spore size (<1.5 µm). High exposures to fungi and bacteria are observed at biofuel plants. Airborne cultivable bacteria are often described to be present in clusters or associated with larger particles with an aerodynamic diameter (d_ae) of 2–8 µm. In this study, we investigate whether airborne fungal components smaller than spore size are present in bioaerosols in working areas at biofuel plants. Furthermore, we measure the exposure to bacteria and fungal components in airborne particulate matter (PM) with a D₅₀ of 1 µm (called PM₁ dust). PM₁ was sampled using Triplex cyclones at a working area at 14 Danish biofuel plants. Millipore cassettes were used to sample ‘total dust’. The PM₁ particles (29 samples) were analysed for content of 11 different components and the total dust was analysed for cultivable fungi, N-acetyl-β-D-glucosaminidase (NAGase), and (1 -> 3)-β-D-glucans. In the 29 PM₁ samples, cultivable fungi were found in six samples and with a median concentration below detection level. Using microscopy, fungal spores were identified in 22 samples. The components NAGase and (1 -> 3)-β-D-glucans, which are mainly associated with fungi, were present in all PM₁ samples. Thermophilic actinomycetes were present in 23 of the 29 PM₁ samples [average = 739 colony-forming units (CFU) m^–3]. Cultivable and ‘total bacteria’ were found in average concentrations of, respectively, 249 CFU m^–3 and 1.8 x 10⁵ m^–3. DNA- and RNA-containing particles of different lengths were counted by microscopy and revealed a high concentration of particles with a length of 0.5–1.5 µm and only few particles >1.5 µm. The number of cultivable fungi and β-glucan in the total dust correlated significantly with the number of DNA/RNA-containing particles with lengths of between 1.0 and 1.5 µm, with DNA/RNA-containing particles >1.5 µm, and with other fungal components in PM₁ dust. Airborne β-glucan and NAGase were found in PM₁ samples where no cultivable fungi were present, and β-glucan and NAGase were found in higher concentrations per fungal spore in PM₁ dust than in total dust. This indicates that fungal particles smaller than fungal spore size are present in the air at the plants. Furthermore, many bacteria, including actinomycetes, were present in PM₁ dust. Only 0.2% of the bacteria in PM₁ dust were cultivable.

N-Acetyl-S-(n-Propyl)-L-Cysteine in Urine from Workers Exposed to 1-Bromopropane in Foam Cushion Spray Adhesives

Hanley, K. W., Petersen, M. R., Cheever, K. L., Luo, L. — Wed, 07 Oct 2009 07:13:12 PDT

1-Bromopropane (1-BP) has been marketed as an alternative for ozone depleting and other solvents; it is used in aerosol products, adhesives, metal, precision, and electronics cleaning solvents. Mechanisms of toxicity of 1-BP are not fully understood, but it may be a neurological and reproductive toxicant. Sparse exposure information prompted this study using 1-BP air sampling and urinary metabolites. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving debromination. Research objectives were to evaluate the utility of urinary N-acetyl-S-(n-propyl)-L-cysteine (AcPrCys) for assessing exposure to 1-BP and compare it to urinary bromide [Br^(–)] previously reported for these workers. Forty-eight-hour urine specimens were obtained from 30 workers at two factories where 1-BP spray adhesives were used to construct polyurethane foam seat cushions. Urine specimens were also obtained from 21 unexposed control subjects. All the workers' urine was collected into composite samples representing three time intervals: at work, after work but before bedtime, and upon awakening. Time-weighted average (TWA) geometric mean breathing zone concentrations were 92.4 and 10.5 p.p.m. for spraying and non-spraying jobs, respectively. Urinary AcPrCys showed the same trend as TWA exposures to 1-BP: higher levels were observed for sprayers. Associations of AcPrCys concentrations, adjusted for creatinine, with 1-BP TWA exposure were statistically significant for both sprayers (P < 0.05) and non-sprayers (P < 0.01). Spearman correlation coefficients for AcPrCys and Br^(–) analyses determined from the same urine specimens were highly correlated (P < 0.0001). This study confirms that urinary AcPrCys is an important 1-BP metabolite and an effective biomarker for highly exposed foam cushion workers.

Permeation of Hair Dye Ingredients through Gloves

Packham, C. L. — Wed, 07 Oct 2009 07:13:12 PDT

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Lin, Y.-W. — Wed, 07 Oct 2009 07:13:12 PDT

Investigation of PAH Biomarkers in the Urine of Workers Exposed to Hot Asphalt

Fri, 07 Aug 2009 19:11:26 PDT

Airborne emissions from hot asphalt contain mixtures of polycyclic aromatic hydrocarbons (PAHs), including several carcinogens. We investigated urinary biomarkers of three PAHs, namely naphthalene (Nap), phenanthrene (Phe), and pyrene (Pyr) in 20 road-paving workers exposed to hot asphalt and in 6 road milling workers who were not using hot asphalt (reference group). Our analysis included baseline urine samples as well as postshift, bedtime, and morning samples collected over three consecutive days. We measured unmetabolized Nap (U-Nap) and Phe (U-Phe) as well as the monohydroxylated metabolites of Nap (OH-Nap), Phe (OH-Phe), and Pyr (OH-Pyr) in each urine sample. In baseline samples, no significant differences in biomarker levels were observed between pavers and millers, suggesting similar background exposures. In postshift, bedtime, and morning urine samples, the high pairwise correlations observed between levels of all biomarkers suggest common exposure sources. Among pavers, levels of all biomarkers were significantly elevated in postshift samples, indicating rapid uptake and elimination of PAHs following exposure to hot asphalt (biomarker levels were not elevated among millers). Results from linear mixed-effects models of levels of U-Nap, U-Phe, OH-Phe, and OH-Pyr across pavers showed significant effects of work assignments with roller operators having lower biomarker levels than the other workers. However, no work-related effect was observed for levels of OH-Nap, apparently due to the influence of cigarette smoking. Biological half-lives, estimated from regression coefficients for time among pavers, were 8 h for U-Phe, 10 h for U-Nap, 13 h for OH-Phe and OH-Pyr, and 26 h for OH-Nap. These results support the use of U-Nap, U-Phe, OH-Phe, and OH-Pyr, but probably not OH-Nap, as short-term biomarkers of exposure to PAHs emanating from hot asphalt.

Comparing Urinary Biomarkers of Airborne and Dermal Exposure to Polycyclic Aromatic Compounds in Asphalt-Exposed Workers

Fri, 07 Aug 2009 19:11:27 PDT

When working with hot mix asphalt, road pavers are exposed to polycyclic aromatic hydrocarbons (PAHs) through the inhalation of vapors and particulate matter (PM) and through dermal contact with PM and contaminated surfaces. Several PAHs with four to six rings are potent carcinogens which reside in these particulate emissions. Since urinary biomarkers of large PAHs are rarely detectable in asphalt workers, attention has focused upon urinary levels of the more volatile and abundant two-ring and three-ring PAHs as potential biomarkers of PAH exposure. Here, we compare levels of particulate polycyclic aromatic compounds (P-PACs, a group of aromatic hydrocarbons containing PAHs and heterocyclic compounds with four or more rings) in air and dermal patch samples from 20 road pavers to the corresponding urinary levels of naphthalene (U-Nap) (two rings), phenanthrene (U-Phe) (three rings), monohydroxylated metabolites of naphthalene (OH-Nap) and phenanthrene (OH-Phe), and 1-hydroxypyrene (OH-Pyr) (four rings), the most widely used biomarker of PAH exposure. For each worker, daily breathing-zone air (n = 55) and dermal patch samples (n = 56) were collected on three consecutive workdays along with postshift, bedtime, and morning urine samples (n = 149). Measured levels of P-PACs and the urinary analytes were used to statistically model exposure–biomarker relationships while controlling for urinary creatinine, smoking status, age, body mass index, and the timing of urine sampling. Levels of OH-Phe in urine collected postshift, at bedtime, and the following morning were all significantly associated with levels of P-PACs in air and dermal patch samples. For U-Nap, U-Phe, and OH-Pyr, both air and dermal patch measurements of P-PACs were significant predictors of postshift urine levels, and dermal patch measurements were significant predictors of bedtime urine levels (all three analytes) and morning urine levels (U-Nap and OH-Pyr only). Significant effects of creatinine concentration were observed for all analytes, and modest effects of smoking status and body mass index were observed for U-Phe and OH-Pyr, respectively. Levels of OH-Nap were not associated with P-PAC measurements in air or dermal patch samples but were significantly affected by smoking status, age, day of sample collection, and urinary creatinine. We conclude that U-Nap, U-Phe, OH-Phe, and OH-Pyr can be used as biomarkers of exposure to particulate asphalt emissions, with OH-Phe being the most promising candidate. Indications that levels of U-Nap, U-Phe, and OH-Pyr were significantly associated with dermal patch measurements well into the evening after a given work shift, combined with the small ratios of within-person variance components to between-person variance components at bedtime, suggest that bedtime measurements may be useful for investigating dermal PAH exposures.

Dermal Exposure of Pesticide Applicators as a Measure of Coverall Performance Under Field Conditions

Machera, K., Tsakirakis, A., Charistou, A., Anastasiadou, P., Glass, C. R. — Fri, 07 Aug 2009 19:11:27 PDT

In this study, the field performance of two coverall designs used by pesticide applicators was determined. Two coverall types were selected based on data from previously conducted comfort testing under field conditions in southern Europe. Dermal exposure was measured during 22 applications conducted with 11 operators using similar hand-held spray guns in greenhouse pepper crops in the Ierapetra region of Crete, Greece. One of the coverall designs studied was made from a cotton/polyester material treated with a water-repellent Resist Spills® finish, which was compared in the field study to a coverall of similar design, but using a woven, untreated cotton material. An in-house analytical method was developed and validated for determining residues of the active substance (a.s.) malathion on the dosimeters. The derived levels of dermal exposure were used as a measure of the protection provided by the two types of coveralls. In addition, by comparing the total amount of the a.s. recovered from outer and inner dosimeters (potential dermal exposure = 238.8 mg kg^–1 a.s. for the cotton coverall and 160.44 mg kg^–1 a.s. for the Resist Spills coverall), a value could be determined for the degree of coverall penetration. The mean penetration (milligrams per kilogram a.s.) of the outer coveralls, calculated as a percentage of the total contamination, was 0.4% for the water-repellent coverall and 2.3% for the cotton coverall. The mean recovery from the laboratory and field-fortified samples was >91 and 74%, respectively and used as the main criterion for quality control of the analytical data. Under the field trial conditions evaluated, both the coverall designs gave better protection than the default values used in the most relevant predictive exposure model. Therefore, they could be considered as appropriate tools of personal protection when both comfort and field performance is taken into account under the specific application scenario.

Field and Wind Tunnel Comparison of Four Aerosol Samplers Using Agricultural Dusts

Fri, 07 Aug 2009 19:11:27 PDT

Occupational lung disease is a significant problem among agricultural workers exposed to organic dusts. Measurements of exposure in agricultural environments in the USA have traditionally been conducted using 37-mm closed-face cassettes (CFCs) and respirable Cyclones. Inhalable aerosol samplers offer significant improvement for dose estimation studies to reduce respiratory disease. The goals of this study were to determine correction factors between the inhalable samplers (IOM and Button) and the CFC and Cyclone for dusts sampled in livestock buildings and to determine whether these factors vary among livestock types. Determination of these correction factors will allow comparison between inhalable measurements and historical measurements. Ten sets of samples were collected in swine, chicken, turkey, and dairy facilities in both Colorado and Iowa. Pairs of each sampling device were attached to the front and back of a rotating mannequin. Laboratory studies using a still-air chamber and a wind tunnel provided information regarding the effect of wind speed on sampler performance. Overall, the IOM had the lowest coefficient of variation (best precision) and was least affected by changes in wind speed. The performance of the Button was negatively impacted in poultry environments where larger (feather) particulates clogged the holes in the initial screen. The CFC/IOM ratios are important for comparisons between newer and older studies. Wind speed and dust type were both important factors affecting ratios. Based on the field studies (Table 6), a ratio of 0.56 is suggested as a conversion factor for the CFC/IOM (average for all environments because of no statistical difference). Suggested conversion factors for the Button/IOM are swine (0.57), chicken (0.80), turkey (0.53), and dairy (0.67). Any attempt to apply a conversion factor between the Cyclone and inhalable samplers is not recommended.

Exposure to Inhalable Dust, Endotoxins, {beta}(1->3)-Glucans, and Airborne Microorganisms in Horse Stables

Fri, 07 Aug 2009 19:11:27 PDT

Objectives: Workers in horse stables are likely exposed to high levels of organic dust. Organic dusts play a role in increased risk of inflammatory reactions and are associated with respiratory diseases. The aim of this study was to investigate dust, endotoxin, β(1->3)-glucan, and culturable microorganisms exposure levels in horse stables.

Methods: Ambient (n = 38) and personal (n = 42) inhalable dust samples were collected using PAS-6 sampling heads. As a special measurement, we included sampling near the horses’ heads. Samples were analyzed for endotoxin and β(1->3)-glucan by Limulus amebocyte lysate assay and an inhibition enzyme immunoassay, respectively. Culturable bacteria and fungi were collected with an Anderson impactor.

Results: Geometric means (GMs) of personal exposure to dust, endotoxin, and β(1->3)-glucan were 1.4 mg m^–3 (range 0.2–9.5), 608 EU m^–3 (20–9846), and 9.5 µg m^–3 (0.4–631 µg m^–3), respectively. Exposure levels in the morning shift were higher compared to other shifts. The GMs (ranges) of culturable bacteria and fungi were 3.1 x 10³ colony-forming unit (CFU) m^–3 (6.7 x 10 to 1.9 x 10⁴) and 1.9 x 10³ CFU m^–3 (7.4 x 10 to 2.4 x 10⁴), respectively. Variance components for endotoxin and β(1->3)-glucan were considerably higher than for dust. Based on dummy variable in a mixed regression analysis, the predominant task explaining exposure levels of dust, endotoxin, and β(1->3)-glucan was sweeping the floor. For β(1->3)-glucan, feeding the horse was also an important determinant.

Conclusion: Dust, endotoxin, and β(1->3)-glucan exposure are considerable in horse stables. Bacterial and fungal exposure levels were moderate. Endotoxin exposures were above the Dutch proposed standard limits, suggesting workers in horse stables to be at risk of adverse health effects.

Predictors of Hearing Protection Use in Construction Workers

Fri, 07 Aug 2009 19:11:27 PDT

Objectives: Although noise-induced hearing loss is completely preventable, it remains highly prevalent among construction workers. Hearing protection devices (HPDs) are commonly relied upon for exposure reduction in construction, but their use is complicated by intermittent and highly variable noise, inadequate industry support for hearing conservation, and lax regulatory enforcement.

Methods: As part of an intervention study designed to promote HPD use in the construction industry, we enrolled a cohort of 268 construction workers from a variety of trades at eight sites and evaluated their use of HPDs at baseline. We measured HPD use with two instruments, a questionnaire survey and a validated combination of activity logs with simultaneous dosimetry measurements. With these measurements, we evaluated potential predictors of HPD use based on components of Pender's revised health promotion model (HPM) and safety climate factors.

Results: Observed full-shift equivalent noise levels were above recommended limits, with a mean of 89.8 ± 4.9 dBA, and workers spent an average of 32.4 ± 18.6% of time in each shift above 85 dBA. We observed a bimodal distribution of HPD use from the activity card/dosimetry measures, with nearly 80% of workers reporting either almost never or almost always using HPDs. Fair agreement (kappa = 0.38) was found between the survey and activity card/dosimetry HPD use measures. Logistic regression models identified site, trade, education level, years in construction, percent of shift in high noise, and five HPM components as important predictors of HPD use at the individual level. Site safety climate factors were also predictors at the group level.

Conclusions: Full-shift equivalent noise levels on the construction sites assessed were well above the level at which HPDs are required, but usage rates were quite low. Understanding and predicting HPD use differs by methods used to assess use (survey versus activity card/dosimetry). Site, trade, and the belief that wearing HPD is not time consuming were the only predictors of HPD use common to both measures on an individual level. At the group level, perceived support for site safety and HPD use proved to be predictive of HPD use.

Comparing Three Methods for Evaluating Impact Wrench Vibration Emissions

McDowell, T. W., Marcotte, P., Warren, C., Welcome, D. E., Dong, R. G. — Fri, 07 Aug 2009 19:11:27 PDT

To provide a means for comparing impact wrenches and similar tools, the international standard ISO 8662-7 prescribes a method for measuring the vibrations at the handles of tools during their operations against a cotton–phenolic braking device. To improve the standard, alternative loading mechanisms have been proposed; one device comprises aluminum blocks with friction brake linings, while another features plate-mounted bolts to provide the tool load. The objective of this study was to evaluate these three loading methods so that tool evaluators can select appropriate loading devices in order to obtain results that can be applied to their specific workplace operations. Six experienced tool operators used five tool models to evaluate the loading mechanisms. The results of this study indicate that different loads can yield different tool comparison results. However, any of the three devices appears to be adequate for initial tool screenings. On the other hand, vibration emissions measured in the laboratory are unlikely to be fully representative of those in the workplace. Therefore, for final tool selections and for reliably assessing workplace vibration exposures, vibration measurements should be collected under actual working conditions. Evaluators need to use appropriate numbers of tools and tool operators in their assessments; recommendations are provided.

Risk Assessment of the Decay of Asbestos Cement Roofs

Fri, 07 Aug 2009 19:11:27 PDT

Objectives: In an assessment of the risk of asbestos fibres release from asbestos cement materials, an important role is played by the assessment of the surface corrosion and by the disaggregation of asbestos cement. The aim of this work is to evaluate the differences among several methods used for the risk assessment that lead to a specific choice of abatement techniques.

Methods: The state of deterioration of 40 asbestos cement roofs was evaluated using two priority assessment algorithms elaborated in Italy, the ‘pull-up test’ described by the Italian Organization for Standardization and the indicators described in the Italian legislation coupled with the observation of a small sample, taken from each roof, by a stereomicroscope.

Results: The results obtained with the methods, proposed in this study, for the risk assessment of the decay of asbestos cement roofs show slight differences among them, only one deviates from the others in judgement on the state of conservation of the roof.

Conclusions: It is very important to train the operator conducting the study since a completely subjectivity-free method does not exist. Whatever method is used will always be affected by the subjectivity linked to the competency and the training of the operator. Moreover, each method on its own cannot assess the risk of exposure to asbestos, but reliable assessment of asbestos-containing materials requires the use of more than one method, such as visual inspections, a pull-up test, and an assessment algorithm.

An International Comparison of the Crystallinity of Calibration Materials for the Analysis of Respirable {alpha}-Quartz Using X-Ray Diffraction and a Comparison with Results from the Infrared KBr Disc Method

Fri, 07 Aug 2009 19:11:27 PDT

It is important that analytical results, produced to demonstrate compliance with exposure limits are comparable, to ensure controls are monitored to similar standards. Correcting a measurement result of respirable -quartz for the percentage of crystalline material in the calibration dust is good analytical practice and significant changes in the values assigned to calibration materials will affect the interpretation of results by an analyst or occupational hygiene professional. The reissue of the certification for the quartz reference material NIST 1878a in 2005 and differences in comparative values obtained by other work created uncertainty about the values of crystallinity assigned to national calibration dusts for -quartz. Members of an International Organization for Standardization working group for silica measurement ISO/TC146/SC2/WG7 collaborated to investigate the comparability of results by X-ray diffraction (XRD) and to reach a consensus.

This paper lists the values recommended by the working group for use with XRD analysis. The values for crystallinity obtained for some of the materials (NIST 1878, Min-U-Sil5 and A9950) were 6–7% lower than the original certification or estimates reported in other comparisons. Crystallinity values obtained by XRD gave a good correlation with BET surface area measurements (r² = 0.91) but not with mean aerodynamic particle size (r² = 0.31). Subsamples of two of the materials (A9950 Respirable and Quin 1 Respirable) with smaller particle size distribution than their parent material did not show any significant change in their values for crystallinity, suggesting that the area XRD measurement of these materials within the particle size range collected is more dependent on how the quartz is formed geologically or how it is processed for use. A comparison of results from laboratories using the infrared (IR) and KBr disc method showed that this method is more dependent than XRD on differences in the particle size within the respirable size range, whereas the XRD values were more consistent between the different measurement values obtained on each material. It was not possible to assign a value for percentage purity to each material for users of IR analysis.

This work suggests that differences are likely to exist between the results from XRD and IR analysis when measuring ‘real’ workplace samples and highlights the importance of matching the particle size of the calibration material to the particle size of the workplace dust for measurements of crystalline quartz.