Workplace Sampling Research Articles

Occupational Exposure to Endotoxin along a Municipal Scale Fecal Sludge Collection and Resource Recovery Process in Kigali, Rwanda.

Background: Little is known about occupational exposures that occur along fecal sludge collection and resource recovery processes. This study characterizes inhaled endotoxin exposure to workers of a municipal scale fecal sludge-to-fuel processes in Kigali, Rwanda. Methods: Forty-two task-based air samples were collected from workers in five tasks along the fecal sludge collection and resource recovery process. Samples were processed for endotoxin using the limulus amebocyte lysate (LAL) test. To account for exposure variability and compare measured concentrations to established exposure limits, we used Monte Carlo modeling methods to construct distributions representing full eight-hour (8-h) exposures to endotoxin across eight exposure scenarios. Results: Geometric mean (GM) endotoxin concentrations in task-based samples ranged from 11–3700 EU/m3 with exposure concentrations increasing as the dryness of the fecal sludge increased through processing. The thermal dryer task had the highest endotoxin concentrations (GM = 3700 EU/m3) and the inlet task had the lowest (GM = 11 EU/m3). The geometric means (GM) of modeled 8-h exposure concentrations were between 6.7–960 EU/m3 and highest for scenarios which included the thermal dryer task in the exposure scenario. Conclusions: Our data suggest the importance of including worker exposure considerations in the design of nascent fecal sludge management processes. The methods used in this study combine workplace sampling with stochastic modeling and are useful for exposure assessment in resource constrained contexts.

Spectrophotometric determination of silicon tetrahydride in the air of workplace.

A new, simple and sensitive method was developed for the determination of silicon tetrahydride in the air of workplace in this study. The alkaline resin-based spherical activated carbon was used to collect sample of silicon tetrahydride at workplace. Silicon tetrahydride was then desorbed from active carbon in 100°C hot water. After reacting with ammonium molybdate, oxalic acid and 1,2,4-trichlorobenzene alpha-naphthol amino sulfonic acid under acid condition, silicon tetrahydride was transformed into silicon molybdenum blue. The absorbance of silicon molybdenum blue was quantitatively measured at the wavelength of 680 nm. The results showed that the average sampling efficiency and desorption efficiency were 97.53% and 94.94%, respectively by this method. Detection limits were 0.054 μg/mL for the spectrophotometric method and 0.14 mg/m(3) for the determination of silicon tetrahydride in the air of workplace (sampling volume was 7.5 L). The conversion rate of silicon tetrahydride gradually decreased when storage time of samples was extended. The descent rate of sample was less than 10% when the sample was sealed for 7 days in the room temperature. It was concluded that this spectrophotometric method can be successfully used to determine silicon tetrahydride in the worksites.

Characterization and validation of sampling and analytical methods for mycotoxins in workplace air

Mycotoxins are produced by certain plant or foodstuff moulds under growing, transport or storage conditions. They are toxic for humans and animals, some are carcinogenic. Methods to monitor occupational exposure to seven of the most frequently occurring airborne mycotoxins have been characterized and validated. Experimental aerosols have been generated from naturally contaminated particles for sampler evaluation. Air samples were collected on foam pads, using the CIP 10 personal aerosol sampler with its inhalable health-related aerosol fraction selector. The samples were subsequently solvent extracted from the sampling media, cleaned using immunoaffinity (IA) columns and analyzed by liquid chromatography with fluorescence detection. Ochratoxin A (OTA) or fumonisin and aflatoxin derivatives were detected and quantified. The quantification limits were 0.015 ng m(-3) OTA, 1 ng m(-3) fumonisins or 0.5 pg m(-3) aflatoxins, with a minimum dust concentration level of 1 mg m(-3) and a 4800 L air volume sampling. The methods were successfully applied to field measurements, which confirmed that workers could be exposed when handling contaminated materials. It was observed that airborne particles may be more contaminated than the bulk material itself. The validated methods have measuring ranges fully adapted to the concentrations found in the workplace. Their performance meets the general requirements laid down for chemical agent measurement procedures, with an expanded uncertainty less than 50% for most mycotoxins. The analytical uncertainty, comprised between 14 and 24%, was quite satisfactory given the low mycotoxin amounts, when compared to the food benchmarks. The methods are now user-friendly enough to be adopted for personal workplace sampling. They will later allow for mycotoxin occupational risk assessment, as only very few quantitative data have been available till now.

Irritancy and Allergic Responses Induced by Exposure to the Indoor Air Chemical 4-Oxopentanal

Over the last two decades, there has been an increasing awareness regarding the potential impact of indoor air pollution on human health. People working in an indoor environment often experience symptoms such as eye, nose, and throat irritation. Investigations into these complaints have ascribed the effects, in part, to compounds emitted from building materials, cleaning/consumer products, and indoor chemistry. One suspect indoor air contaminant that has been identified is the dicarbonyl 4-oxopentanal (4-OPA). 4-OPA is generated through the ozonolysis of squalene and several high-volume production compounds that are commonly found indoors. Following preliminary workplace sampling that identified the presence of 4-OPA, these studies examined the inflammatory and allergic responses to 4-OPA following both dermal and pulmonary exposure using a murine model. 4-OPA was tested in a combined local lymph node assay and identified to be an irritant and sensitizer. A Th1-mediated hypersensitivity response was supported by a positive response in the mouse ear swelling test. Pulmonary exposure to 4-OPA caused a significant elevation in nonspecific airway hyperreactivity, increased numbers of lung-associated lymphocytes and neutrophils, and increased interferon-γ production by lung-associated lymph nodes. These results suggest that both dermal and pulmonary exposure to 4-OPA may elicit irritant and allergic responses and may help to explain some of the adverse health effects associated with poor indoor air quality.

Preparation, certification and interlaboratory analysis of workplace air filters spiked with high-fired beryllium oxide

Occupational sampling and analysis for multiple elements is generally approached using various approved methods from authoritative government sources such as the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA), as well as consensus standards bodies such as ASTM International. The constituents of a sample can exist as unidentified compounds requiring sample preparation to be chosen appropriately, as in the case of beryllium in the form of beryllium oxide (BeO). An interlaboratory study was performed to collect analytical data from volunteer laboratories to examine the effectiveness of methods currently in use for preparation and analysis of samples containing calcined BeO powder. NIST SRM(®) 1877 high-fired BeO powder (1100 to 1200 °C calcining temperature; count median primary particle diameter 0.12 μm) was used to spike air filter media as a representative form of beryllium particulate matter present in workplace sampling that is known to be resistant to dissolution. The BeO powder standard reference material was gravimetrically prepared in a suspension and deposited onto 37 mm mixed cellulose ester air filters at five different levels between 0.5 μg and 25 μg of Be (as BeO). Sample sets consisting of five BeO-spiked filters (in duplicate) and two blank filters, for a total of twelve unique air filter samples per set, were submitted as blind samples to each of 27 participating laboratories. Participants were instructed to follow their current process for sample preparation and utilize their normal analytical methods for processing samples containing substances of this nature. Laboratories using more than one sample preparation and analysis method were provided with more than one sample set. Results from 34 data sets ultimately received from the 27 volunteer laboratories were subjected to applicable statistical analyses. The observed performance data show that sample preparations using nitric acid alone, or combinations of nitric and hydrochloric acids, are not effective for complete extraction of Be from the SRM 1877 refractory BeO particulate matter spiked on air filters; but that effective recovery can be achieved by using sample preparation procedures utilizing either sulfuric or hydrofluoric acid, or by using methodologies involving ammonium bifluoride with heating. Laboratories responsible for quantitative determination of Be in workplace samples that may contain high-fired BeO should use quality assurance schemes that include BeO-spiked sampling media, rather than solely media spiked with soluble Be compounds, and should ensure that methods capable of quantitative digestion of Be from the actual material present are used.

An Investigation of Aircraft Worker Anemia

To identify exposures possibly contributing to anemia cases among hexavalent chromium medical surveillance program enrollees. An investigation encompassed metals surveillance programs, extensive workplace sampling and remediation, consultation, evaluation of laboratory accuracy, and follow-up of anemic individuals. Workers had underlying medical conditions that affected surveillance results. There was a systemic error in classification based on hematocrit value. The prevalence of anemia in a workforce averaging 52 years old was 16%. Anemia may be more prevalent in middle-aged workers than expected. Modern laboratories generally report a calculated hematocrit value, and using hemoglobin for most classification purposes is preferred. Characteristics of a specific workforce, including age, health, hobbies, and diet, should be taken into account when interpreting medical surveillance program findings. The value of a team approach in addressing occupational health problems was demonstrated.

作業環境測定基準に基づく吸入性粉じんとロウボリウムサンプラ用多段分粒装置の性能評価

The relationship between dust size and penetration for a static horizontal elutriator (Sibata C-30) was measured in calm air. The elutriator as a low-volume air sampler is widely used as a dust size classifier in work environment measurements. The actual penetrations were compared with the theoretical models of the sampler and with sampling convention for respirable dust in work environment measurement. The sampling convention was recently introduced into the Japanese standard for work environment measurement and is based on the ISO 7708 respirable dust convention. The bias of sampled masses from the respirable dust was calculated for two flow rates of the sampler, i.e., 50% cut sizes of 4 microm and 5 microm, from measured penetration curves. The bias of the sampler was overestimated in the 5 microm, 50% cut condition and underestimated in the 4 microm, 50% cut condition for most workplace sampling situations.

Investigation of the competitive rate of derivatization of several secondary amines with phenylisocyanate (PHI), hexamethylene-1,6-diisocyanate (HDI), 4,4'-methylenebis(phenyl isocyanate) (MDI) and toluene diisocyanate (TDI) in liquid medium.

The stabilization of the isocyanate (NCO) groups during workplace sampling is necessary for their subsequent laboratory analysis. Most derivatization reagents are secondary amines. By carrying out a test in which two secondary amines are added to an isocyanate, the relative rates of these reactions can be evaluated. This evaluation is known for a monoisocyanate, phenylisocyanate (PHI), but is being developed for diisocyanates. This study deals with the relative reactivity (RR) of four diisocyanates: hexamethylene 1,6-diisocyanate (HDI), 4,4'-methylenebis(phenyl isocyanate) (MDI), and the ortho and para isomers of toluene diisocyanate (TDI) in addition to PHI, with four secondary amines: 1-(2-methoxyphenyl)piperazine (MOPIP), 9-(N-methylaminomethyl)anthracene (MAMA), 1-(9-anthracenylmethyl)piperazine (MAP), and dibutylamine (DBA). These competitive derivatization reactions are studied in three reaction solvents, namely acetonitrile, toluene, and acetonitrile doped with water (1% v/v). The results show that the order of reactivity, which doesn't change with the isocyanate as well as with the solvent used, is the following: DBA > MAP > MOPIP > MAMA. The relative difference in reactivity is a function of both the isocyanate and the solvent used. Hindered aromatic diisocyanates (TDI and MDI) show a greater difference in reactivity with the derivatization agents. These differences in reactivity are also modified by the solvent used. For example, larger differences are observed in acetonitrile than in toluene, but the introduction of water to acetonitrile, which does not affect the reaction yield, makes these differences smaller.

WORKPLACE VALIDATION OF A LABORATORY EVALUATION TEST OF SAMPLERS FOR INHALABLE AND “TOTAL” DUST

Parallel personal breathing zone sampling of dust with the IOM sampler and the open-face 37 mm filter cassette has been performed at seven plants where dusting processes take place indoors. The particle size distribution in the breathing zone and the amount of dust collected by passive sampling was also determined. The prevailing orientation of the worker in relation to the dust source was noted. Measured ratios of dust concentrations sampled with the open-face 37 mm filter cassette and the IOM sampler were compared with estimated ratios of dust concentrations obtained from the sampled size distributions and published sampling efficiencies of the two samplers determined in a wind-tunnel experiment. The results of the workplace sampling show that at these plants the inhalable size distribution often contained very coarse particles and that the maximum air speed was low, generally less than 0.3 m s -1. The worker mainly faced and handled the predominant dust source. The comparison of the sampled and estimated dust concentration ratios of the open-face 37 mm filter cassette to the IOM sampler showed that the ratio of sampled dust concentrations were 25% lower than estimated. The present test method employed for dust samplers in wind-tunnels may therefore be improved in order to be even more valid for workplace sampling. The cause of the deviation between the workplace and the wind-tunnel could not be found, but the following major differences between the two cases are probably involved: bias in sampling efficiency between electrically insulating and conducting IOM samplers, lower air speed at workplaces than in wind-tunnel experiments, workers handling the source, dust concentration gradients between the collarbone and the lapel.

Chemical data for workplace sampling & analysis, 1997

Chemical data for workplace sampling & analysis, 1997

Characteristics of particle emissions at paint manufacturing

The handling of pigments and powders in paint manufacturing cause emissions of airborne particles. A great variety of substances occur. Previous studies (Bohgard et al., 1994) of simulations of pouring of pigments, which occur in small scale weighing procedures, showed typically bimodal size distribution including a sub-micron and a super-micron mode.The objective of the study was to get detailed knowledge on the relation between different source processes (depending on production technology, equipment and the manual handling routines) and aerosol characteristics.Super-micron particles were continuously measured with a time-of-flight instrument (Aerodynamic Particle Sizer, APS TSI Inc.) and sub-micron particles with an electric mobility spectrometer (Scanning Mobility Particle Sizer, SMPS TSI Inc.). In addition filter sampling techniques for standardised work-place sampling (so-called total dust filter cassettes, a cyclone sampler for respirable dust and IOM-samplers for inhalable dust) have been used for idealised exposure/area measurements using a rotating mannequin as a carrier of these samplers. The filters were analysed gravimetrically and with Particle Induced X-ray Emission Analysis. The aerosols were measured during manufacturing of batches of paint. Sources and source mechanisms, as pouring pigments from bags, disposal of packages, mixing of powders and pigments and suspected re-suspension sources, were documented simultaneously with the performance of the measurements.Figure 1 shows examples of size distributions obtained with the APS and SMPS. The size distributions have essentially bimodal shapes with median diameters of 0.05 -0.4 [mu ]m and of 2-5 [mu ]m respectively. Rapid variation in concentration occurs.Preliminary results show that several sources occur. Irregular activities and events as disposal of package material, cleaning, leakage from conveyor tubes and re-suspension due to wind velocities from open gates and moving vehicles significantly contribute to the particle concentrations.Filter sampling with the samplers mounted on a mannequin torso, rotating 360 degrees forth and back, is advantageous by giving idealised measures on exposure. Samplers mounted on equal horizontal level will have equal sampling location integrated over time. Furthermore, the sampling procedure emulate sampling in accordance with sampling conventions. Inlet characteristics of samplers mounted on a body differ from characteristics of free-hanging samplers (Vincent, 1989). Higher estimated mass concentrations were obtained with the IOM-samplers for inhalable dust than with the 37 mm open-face [ldquo ]total dust[rdquo ] cassettes.Figure omitted (Less)

Field Evaluation of a Sampling and Analytical Method for Environmental Levels of Airborne Hexavalent Chromium

Hexavalent chromium, Cr(VI), has been classified as a human respiratory carcinogen. Airborne Cr(VI) emissions are associated with a number of industrial sources including metal plating, tanning, chromite ore processing, and spray painting operations; combustion sources such as automobiles and incinerators; and fugitive dusts from contaminated soil. There has been considerable interest within industry and the regulatory community to assess the potential cancer risks of workers exposed to Cr(VI) at levels substantially below the threshold limit value (TLV) of 50 µg/m3. To date, only the workplace sampling and analytical method (National Institute for Occupational Safety and Health [NIOSH] Method 7600) has been validated for measuring airborne Cr(VI), and it can accurately measure concentrations only as low as 500 ng/m3. This paper describes the field evaluation of a sampling and analytical method for the quantitation of airborne Cr(VI) at concentrations 5000 times lower than the current standard method (as low as 0.1 ng/m3). The collection method uses three 500-mL Greenberg-Smith impingers in series, operated at 15 Lpm for 24 hr. All three impingers are filled with 200 mL of a slightly alkaline (pH ∼8) sodium bicarbonate buffer solution. The results of validation tests showed that both Cr(VI) and trivalent chromium, Cr(III), were stable in the collection medium and that samples may be stored for up to 100 days without appreciable loss of Cr(VI). Method precision based on the pooled coefficient of variation for replicate samples was 10.4%, and method accuracy based on the mean percent recovery of spiked samples was 94%. Both the precision and accuracy of the impinger method were within NIOSH criteria. This method could be used to measure ambient concentrations of Cr(VI) in the workplace caused by fugitive emissions from manufacturing processes or chromium-contaminated soils at workplace concentrations well below the current TLV (50 µg/m3) or permissible exposure limit (100 µg/m3).

Field evaluation of a sampling and analytical method for environmental levels of airborne hexavalent chromium.

Hexavalent chromium, Cr(VI), has been classified as a human respiratory carcinogen. Airborne Cr(VI) emissions are associated with a number of industrial sources including metal plating, tanning, chromite ore processing, and spray painting operations; combustion sources such as automobiles and incinerators; and fugitive dusts from contaminated soil. There has been considerable interest within industry and the regulatory community to assess the potential cancer risks of workers exposed to Cr(VI) at levels substantially below the threshold limit value (TLV) of 50 micrograms/m3. To date, only the workplace sampling and analytical method (National Institute for Occupational Safety and Health [NIOSH] Method 7600) has been validated for measuring airborne Cr(VI), and it can accurately measure concentrations only as low as 500 ng/m3. This paper describes the field evaluation of a sampling and analytical method for the quantitation of airborne Cr(VI) at concentrations 5000 times lower than the current standard method (as low as 0.1 ng/m3). The collection method uses three 500-mL Greenberg-Smith impingers in series, operated at 15 Lpm for 24 hr. All three impingers are filled with 200 mL of a slightly alkaline (pH approximately 8) sodium bicarbonate buffer solution. The results of validation tests showed that both Cr(VI) and trivalent chromium, Cr(III), were stable in the collection medium and that samples may be stored for up to 100 days without appreciable loss of Cr(VI). Method precision based on the pooled coefficient of variation for replicate samples was 10.4%, and method accuracy based on the mean percent recovery of spiked samples was 94%. Both the precision and accuracy of the impinger method were within NIOSH criteria. This method could be used to measure ambient concentrations of Cr(VI) in the workplace caused by fugitive emissions from manufacturing processes or chromium-contaminated soils at workplace concentrations well below the current TLV (50 micrograms/m3) or permissible exposure limit (100 micrograms/m3).

Sample loss during measurement of airborne antineoplastic agents.

Handling, preparation and administration of antineoplastic drugs are suspected health hazards for hospital and clinic personnel. Measurement of personal and area exposures to such materials in air is difficult because the average concentration is often close to the analytical detection limit. For this reason, and because of the random nature of drug spills and releases, the sampling method of choice typically extends over a 40-hour workweek. In this study a method for monitoring two airborne antineoplastic drugs, fluorouracil and methotrexate, was tested for possible loss of the drug from filters during air sampling. Glass-fiber filters (37 mm) were spiked with known amounts of drug and subjected to the same airflow conditions as are used in workplace sampling. Filter extracts were analyzed using high performance liquid chromatography (HPLC). Losses during storage up to a month were less than 5% for both drugs. Losses during airflow were directly proportional to cumulative air volume, 2% of the amount on the spiked filter/m3 air for fluorouracil and 6%/m3 for methotrexate. Losses during actual collection will be less and ordinarily are not expected to constitute a major hindrance to extended sampling in occupational settings.

Particle Size-Selective Sampling in the Workplace: Rationale and Recommended Techniques

Ann. occup. Hyg .. Vol. 32, pp. 403-411 Supplement I, 1988. Printed in Great Britain Inhaled Particles VI Pergamon Press pie 1988 British Occupational Hygiene Society. PARTICLE SIZE-SELECTIVE SAMPLING IN THE WORKPLACE: RATIONALE AND RECOMMENDED TECHNIQUES R.F. PHALEN•, W.C. HINDSt, W. JOHNt, P.J. LIOY§, M. LIPPMANN§, M .A. MCCAWLEY~ , 0.G. RAABE\!, S .C. SODERHOLM** and B.0 . STUARTt t •University of California, Irvine, CA, 92717, U.S.A., t University of California, Los Angeles, CA, 90024, U.S.A., t California Department of Health Services, Berkeley. CA, 94704, U.S.A., § New York University Medical Center, Tuxedo, NY, 10987, U.S.A., 11 N.1.0.S.H., Morgantown, WV, 26505, U.S.A., II University of California, Davis, CA, 95616, U.S.A., .. University of Rochester, Rochester, NY, 14642, U.S.A. and tt Air Force Armstrong Aerospace Medical Rsh. Lab., WPAFB, OH, 45433, U.S.A. Abstract- Because many aerosol hazards are dependent upon particle size, the American Conference of Governmental Industrial Hygienists established an Air Sampling Procedures Committee to 'recommend size-selective aerosol sampling procedures which will permit reliable collection of aerosol fractions which can be expected to be available for deposition in the various major subregions of the human respiratory tract, e.g., the head, tracheobronchial region, and the alveolar (pulmonary) region.' After reviewing available data on regional deposition of inhaled particles and on the collection efficiencies of sampling instruments, the committee recommends use of three particulate mass fractions for workplace sampling. Inspirable Particulate Mass applies to material which is hazardous anywhere in the respiratory tract; Thoracic Particulate Mass applies to materials which are hazardous anywhere within the lung airways and the gas exchange region; Respirable Particulate Mass applies to material which is hazardous only in the gas-exchange region of the lung. Each of these 3 mass fractions are defined and a procedure to provide guidance in establishing corresponding Particle Size-Selective Threshold Limit Values (PSS-TL Vs) has been suggested. INTRODUCTION DESPITE THE EVIDENCE that aerosol particle size can greatly modify responses to inhaled materials, the use of particle-size selective sampling for worker or public protection has only been applied in a few circumstances. Included are the British Medical Research Council's and the U.S. Atomic-Energy Commission's definitions of 'respirable dust', the American Conference of Governmental Industrial Hygienists' (ACGIH) Threshold Limit Values (TL Vs) for quartz, cristobalite and tridymite; and the U.S. EPA's and the International Standards Organization's (ISO) definitions of aerosol fractions related to particle deposition within regions of the human respiratory tract (Air Sampling Procedures Committee, 1985). What follows is a brief summary of the report of the ACGIH technical committee on Air Sampling Procedures which was formed to recommend size-selective aerosol sampling procedures in workplaces (AIR SAMPLING PROCEDURES COMMITTEE, 1985). Respiratory tract regions Table I shows the major anatomical regions (and their included structures) considered in recommending aerosol sampling techniques. Also shown are essentially

Rationale and Recommendations for Particle Size-Selective Sampling in the Workplace

Abstract Because many aerosol hazards depend upon particle size, the American Conference of Governmental Industrial Hygienists established an Air Sampling Procedures Committee to “recommend size-selective aerosol sampling procedures which will permit reliable collection of aerosol fractions which can be expected to be available for deposition in the various major subregions of the human respiratory tract.” After reviewing available data on regional deposition of inhaled particles and on the collection efficiencies of sampling instruments, the committee recommends use of three particulate mass fractions for workplace sampling: inspirable particulate mass (IPM), for materials which may be hazardous anywhere in the respiratory tract; thoracic particulate mass (TPM), for materials which may be hazardous anywhere within the lung airways and the gas exchange region; and respirable particulate mass (RPM), for materials which may be hazardous in the gas exchange region of the lung. The mass fractions are defined ...