Industrial Hygiene Sampling Research Articles

Male reproductive effects of solvent and fuel exposure during aircraft maintenance

Few studies have addressed the effects of mixed, low-level exposures to complex mixtures on a man’s reproductive potential. In this prospective study, each subject was evaluated before first exposure and at 15 and 30 weeks after exposures had begun. A total of 50 men working on aircraft maintenance at an Air Force installation were included in the study. In addition, eight unexposed men were concurrently sampled. Industrial hygiene (IH) sampling and expired breath samples were collected for jet fuel as measured by total napthas, benzene—a component of jet fuel, 1,1,1-trichloroethane, methyl ethyl ketone, xylenes, toluene, and methylene chloride. Sperm production, structure, and function (sperm concentration, sperm motion, viability, morphology, morphometrics, and stability of sperm chromatin) were evaluated. Exposures were low. All mean IH measures were below 6 ppm, which is less than 10% of the Occupational Safety and Health Administration standard for all chemicals except benzene. Sheet metal workers had the highest mean breath levels for both total solvents (24 ppb) and fuels (28.3 ppb). For most sperm measures, mean values remained in the normal range throughout the 30 weeks of exposure. When jobs were analyzed by exposure groups, some adverse changes were observed. The paint shop group had a significant decline in motility of 19.5% at 30 weeks. Internal dose measures, however, did not show a significant association with spermatogenic changes.

Field method for the determination of hexavalent chromium by ultrasonication and strong anion-exchange solid-phase extraction.

A simple, fast, sensitive, and economical field method was developed and evaluated for the determination of hexavalent chromium (CrVI) in environmental and workplace air samples. By means of ultrasonic extraction in combination with a strong anion-exchange solid-phase extraction (SAE-SPE) technique, the filtration, isolation, and determination of CrVI in the presence of trivalent chromium (CrIII) and potential interferents was achieved. The method entails (1) ultrasonication in basic ammonium buffer solution to extract CrVI from environmental matrixes; (2) SAE-SPE to separate CrVI from CrIII and interferences; (3) elution/acidification of the eluate; (4) complexation of chromium with 1,5-diphenylcarbazide; and (5) spectrophotometric determination of the colored chromium-diphenylcarbazone complex. Several critical parameters were optimized in order to effect the extraction of both soluble (K2CrO4) and insoluble (PbCrO4) forms of CrVI without inducing CrIII oxidation or CrVI reduction. The method allowed for the dissolution and purification of CrVI from environmental and workplace air sample matrixes for up to 24 samples simultaneously in less than 90 min (including ultrasonication). The results demonstrated that the method was simple, fast, quantitative, and sufficiently sensitive for the determination of occupational exposures of CrVI. The method is applicable for on-site monitoring of CrVI in environmental and industrial hygiene samples.

Building-related illness and employee lost time following application of hot asphalt roof: a call for prevention.

Industrial hygiene sampling within an office building during and following a roof renovation revealed low-level exposure to high-boiling organic compounds, associated with complaints of eye and upper respiratory tract irritation among building occupants. Health complaints continued substantially beyond the time frame of the renovation completion, despite a lack of objective industrial hygiene findings for volatile organic compounds (VOCs) and microbiological contamination, and a lack of consistent medical findings among employees evaluated by an occupational physician. An analysis of employee attendance records suggests lost attendance and reduced productivity costs. Preventive strategies include proper planning and scheduling of building renovations to prevent employee exposure to asphalt roof emissions.

Ultrasonic extraction of heavy metals from environmental and industrial hygiene samples for their subsequent determination

Ultrasonic extraction (UE) is an effective method for the extraction of a number of heavy metals in environmental samples. In many cases, UE offers a means for quantitative recoveries of heavy metals. However, UE has been underutilized for sample preparation purposes in environmental analysis. Nevertheless, the use of UE for extraction of heavy metals in the industrial hygiene arena is increasing, with applications in the field as well as in the laboratory. In this article some examples of applications of UE to heavy metals extraction (for their subsequent determination) in environmental and industrial hygiene samples are presented. It is expected that the use of UE for sample preparation purposes in environmental analytical chemistry will become more widespread, owing to its simplicity, ease of use, speed, and enhanced safety when compared with other, more traditional sample preparation procedures.

Jet Fuel Exposure in the United States Air Force

Abstract Jet fuel vapor exposures were measured using industrial hygiene sampling techniques at three domestic U.S. Air Force installations. Breathing zone samples were collected from within three general job categories at each location: aircraft maintenance, fuel handling, and flightline positions. These samples were analyzed using gas chromatography and flame ionization detector techniques. Mean exposure concentrations for all samples collected were 0.01 ppm benzene [standard deviation (SD) = 0.01] and 1.33 ppm naphthas/jet fuels (SD = 1.95) for the aircraft maintenance positions (n = 63), 0.01 ppm benzene (SD = 0.01) and 0.61 ppm naphthas/jet fuels (SD = 0.90) for fuel handling positions (n = 16), and 0.004 ppm benzene (SD = 0.005) and 0.33 ppm naphthas/jet fuels (SD = 0.40) for flightline positions (n = 8).

Determination of hexavalent chromium in industrial hygiene samples using ultrasonic extraction and flow injection analysis.

A simple, fast, and sensitive method was developed for the determination of hexavalent chromium (CrVI) in workplace samples. Ultrasonic extraction in alkaline solutions with 0.05 M (NH4)2SO4-0.05 M NH3 provided good extraction efficiency of CrVI from the sample and allowed the retention of CrVI on an ion-exchange resin (95%). The CrVI in the sample solution was then separated as an anion from trivalent chromium [CrIII] and other cations by elution from the anion-exchange resin with 0.5 M (NH4)2SO4 in 0.1 M NH3 (pH 8) buffer solution. The eluate was then acidified with hydrochloric acid and complexed with 1,5-diphenylcarbazide reagent prior to flow injection analysis. By analyzing samples with and without oxidation of CrIII to CrVI using CeIV, the method can measure CrVI and total Cr. For optimizing the separation and determination procedure, preliminary trials conducted with two certified reference materials (CRMs 013-050 and NIST 1633a) and three spiked samples (ammonia buffer solution, cellulose ester filters and acid washed sand) indicated that the recovery of CrVI was quantitative (> 90%) with this method. The limit of detection for FIA-UV/VIS determination of the Cr-diphenylcarbazone complex was in the sub-nanogram range (0.11 ng). The technique was also applied successfully to a workplace coal fly ash sample that was collected from a power plant and paint chips that were collected from a heating gas pipe and a university building. The principal advantages of this method are its simplicity, sensitivity, speed and potential portability for field analysis.

Balancing cost and precision in exposure assessment studies.

Because of the cost involved both for personnel and laboratory analyses, it is incumbent that industrial hygiene (IH) sampling plans be both precise and cost effective. The purpose of this paper is to describe a method of balancing two opposing objectives, increasing precision and decreasing the cost by manipulating the number and nature of IH sample collections. Data from a pilot study were used to obtain an optimum sampling scheme for exposure assessment. The design that obtains the highest precision while controlling costs serves as the model of choice. An approach is illustrated with data from an ongoing study examining health effects of workers exposed to solvents. It is shown that there is a large variation in precision for identical IH measurements, depending on the efficiency of the sampling schedule.

Emissions from mesoscale in situ oil fires: the mobile 1991 experiments

A series of 14 mesoscale burns were conducted in 1991 to study various aspects of oil burning in situ. Extensive sampling and monitoring of these burns were conducted to determine the emissions. This was done at two downwind ground stations, one upwind ground station and in the smoke plume using a blimp and a remote-controlled helicopter. Particulate samples in air were taken and analyzed for polycyclic aromatic hydrocarbons (PAHs). PAHs were found to be lower in the soot than in the starting oil. Metals in the oil were found concentrated in the residue and could not be measured in soot samples using conventional industrial hygiene sampling techniques. Particulates in the air were measured by several means and found to be greater than recommended exposure levels only up to 150 m downwind at ground level. Combustion gases including carbon dioxide, sulphur dioxide and carbon monoxide did not reach exposure level maximums. These gases were emitted over a broad area around the fire and are not directly associated with the plume trajectory. Volatile organic compound (VOCs) emissions are extensive from fires, but the levels are less than those emitted from a non-burning test spill. Over 50 compounds were identified and quantified, several at possible levels of concern up to 200 m downwind. Water under the burns was analyzed; no analytes of concern could be found at the detection levels of the methods. The burn residue was analyzed for the same compounds as the air particulate samples. The residue contained elevated amounts of metals. PAHs were at a lower concentration in the residue than in the starting oil, however there is a slight differential concentration increase in some higher molecular weight species. Overall, indications from these mesoscale trials are that emissions from in situ burning are low in comparison to other sources of emissions and result in concentrations of air contaminants that are below exposure limits beyond 500 m downwind.

Relationship Between Phase Contrast Microscopy and Transmission Electron Microscopy Results of Samples from Occupational Exposure to Airborne Chrysotile Asbestos

Transmission electron microscope (TEM) and phase contrast microscope (PCM) fiber counts from the same filter were compared. Industrial hygiene samples from operations within a chrysotile mine, crusher, mill and tailings site, a brake manufacturing industry, and a taping products manufacturer were used. A total of 10 318 individual fibers were analyzed from 65 filter samples. The aim of the study was to derive the relationships between TEM counts and PCM counts that could be used in the extrapolation of risk estimate from occupational exposure to low-level nonoccupational exposure to asbestos. The results show that ratios of EM-PCM equivalent to PCM counts vary between 1.4 to 3.2. The proportion of long thin fibers (L>8 µm, D<1.5 µm) increased as the asbestos operation moved from primary sector (mining) to end use sector (manufacturing).

Electroanalytical applications in occupational and environmental health

AbstractElectroanalytical chemistry has been used for years in the occupational and environmental health fields. Portable sensors and analytical devices based on electrochemical (EC) methods are commonly used on‐site in the workplace. Laboratory EC methods also have been used extensively for the analysis of industrial hygiene and related samples. Recent advances in electroanalytical methodology may lead to new analytical applications in the occupational health arena, both in the laboratory as well as on‐site in the workplace. Applications in heavy metals analysis, analysis for inorganic and organic species, and bioanalysis are exemplified. This article provides an overview of the history of EC analysis for industrial hygiene purposes, and also summarizes current and newly developed applications of electroanalytical methods in occupational and environmental health.

Workplace Simulations: An Alternative to On-Site Industrial Hygiene Sampling

Abstract Numerous hazardous agents are present in the workplaces of the construction industries. Conducting an on-site industrial hygiene survey in some phases of these industries can be difficult, if not impossible. An example is the evaluation of hazards arising in the cutting of epoxy-coated steel reinforcing rod (coated rod) in the structural steel erection industry (SIC 1791). When necessary, coated rod is cut using either a gasoline-powered cut-off saw or an oxy-acetylene cutting torch. Using either method generates smoke and dust that may be hazardous in their own right or that may contain hazardous materials such as combustion products of the epoxy resin coating. Typically, cutting coated rod is an unscheduled event that may have to be done quickly, as this phase of construction usually involves pouring large volumes of fresh (wet) concrete. It is not practical to anticipate such an event and to have industrial hygiene personnel and equipment standing by on-site to perform necessary industrial hyg...

Observations on the dose-response curve for arsenic exposure and lung cancer.

Occupational studies in three countries have related quantitative estimates of arsenic exposure to lung cancer risks. Mine exposures in China appear to incur a higher relative risk than arsenic exposures elsewhere. All of the studies with quantitative data are consistent with a supralinear dose-response relationship. Two studies are also consistent with a linear relationship over an elevated background risk of lung cancer among arsenic-exposed workers. Neither toxicokinetic mechanisms nor confounding from age, smoking, or other workplace carcinogens that differ by exposure level appear likely to explain this curvilinearity. Plausible explanations include (i) synergism (with smoking) which varies in magnitude according to the level of arsenic exposure, (ii) long-term survivorship in higher exposure jobs among the healthier, less susceptible individuals, (iii) exposure estimate errors that were more prominent at higher exposure levels as a result of past industrial hygiene sampling or worker protection practices.

Decrements in neurobehavioral performance associated with mixed exposure to organic and inorganic lead.

In 1990, 222 current employees of a chemical facility in the eastern United States that manufactured tetraethyl lead were administered a neurobehavioral test battery, tests of olfactory function and peripheral vibration threshold, and questionnaires that assessed neuropsychiatric symptoms. A cumulative variable of exposure to inorganic and organic lead was derived from 12 years of personal industrial hygiene sampling data and an occupational history interview that assessed work in each of 29 exposure zones in the lead area. The range of assigned exposure intensities in these 29 zones was 4-119 micrograms/m3 for organic lead and 1-56 micrograms/m3 for inorganic lead. Cumulative lead exposure and exposure duration were defined as categorical variables (four groups) in multiple linear regression models. The adjusted mean differences in neurobehavioral test scores were estimated by comparing the average scores of the moderate, high, and highest exposure groups with the low exposure (reference) group. After adjustment for premorbid intellectual ability, age, race, and alcohol consumption, neurobehavioral test scores were poorer as measures of both cumulative lead exposure and exposure duration increased; many of the associations evidenced dose-response relations. Associations were observed in most cognitive and functional domains tested, but were most common in two domains: manual dexterity and verbal memory/learning. On the affected neuropsychologic measures, the groups with the highest exposure averaged scores 5-22% lower than those of the reference groups. Overall, the data revealed generally consistent and coherent associations between two measures of lead exposure and poorer neurobehavioral test performance.

Assessment of arsenic exposures and controls in gallium arsenide production.

The electronics industry is expanding the use of gallium arsenide in the production of optoelectronic devices and integrated circuits. Workers in the electronics industry using gallium arsenide are exposed to hazardous substances such as arsenic, arsine, and various acids. Arsenic requires stringent controls to minimize exposures (the current OSHA PEL for arsenic is 10 micrograms/m3 and the NIOSH REL is 2 micrograms/m3 ceiling). Inorganic arsenic is strongly implicated in respiratory tract and skin cancer. For these reasons, NIOSH researchers conducted a study of control systems for facilities using gallium arsenide. Seven walk-through surveys were performed to identify locations for detailed study which appeared to have effective controls; three facilities were chosen for in-depth evaluation. The controls were evaluated by industrial hygiene sampling. Including personal breathing zone and area air sampling for arsenic and arsine; wipe samples for arsenic also were collected. Work practices and the use of personal protective equipment were documented. This paper reports on the controls and the arsenic exposure results from the evaluation of the following gallium arsenide processes: Liquid Encapsulated Czochralski (LEC) and Horizontal Bridgeman (HB) crystal growing, LEC cleaning operations, ingot grinding/wafer sawing, and epitaxy. Results at one plant showed that in all processes except epitaxy, average arsenic exposures were at or above the OSHA action level of 5 micrograms/m3. While cleaning the LEC crystal pullers, the average potential arsenic exposure of the cleaning operators was 100 times the OSHA PEL. At the other two plants, personal exposures for arsenic were well controlled in LEC, LEC cleaning, grinding/sawing, and epitaxy operations.

A Distribution-Free Double-Sampling Method for Exposure Assessment

Abstract Many industrial hygiene sampling surveys are conducted to gather a sufficient amount of information for making a decision on the acceptability of exposures in a workplace. The sampling strategy reported here, which is exposure concentration distribution free and small sample based, is a modification of the double-sampling strategies used in quality control. The sampling strategy is predicated on the premise that the exposures are acceptable if the concentrations exceed a quality control level (QCL) on the average no more than a small fraction of the time (tolerance level). Before the sampling is carried out, a QCL, a tolerance, a confidence level, and a small number for initial samples to be taken are selected. On the basis of the number of samples that exceed the QCL, a decision to accept or reject the conditions in the workplace is made. The results presented here suggest that an initial sample size of 4 to 10 should be satisfactory for almost all conditions. The QCL and the tolerance level chosen are intimately connected. In a rudimentary form, the health effects of an agent may be assumed to be correlated either to the level of an integrated exposure over some period of time (Type I) or to the level of peak exposure over a brief period of time (Type II). For agents with Type I characteristics, the QCL selection process is straightforward and guidelines for this process are described in detail. A different but related QCL selection process is required for the agents with Type II characteristics. Unfortunately, for Type II contaminants the QCL selection is uncertain.

A QUANTITATIVE APPROACH TO THE CHARACTERIZATION OF CUMULATIVE AND AVERAGE SOLVENT EXPOSURE IN PAIN MANUFACTURING PLANTS

Previous reports have attributed a range of neurobehavioral effects to low-level, occupational solvent exposure. These studies have generally been limited in their exposure assessments and have specifically lacked good estimates of exposure intensity. In the present study, the authors describe the development of two exposure variables that quantitatively integrate industrial hygiene sampling data with estimates of exposure duration--a cumulative exposure (CE) estimate and a lifetime weighted average exposure (LWAE) estimate. Detailed occupational histories were obtained from 187 workers at two paint manufacturing plants. Historic industrial hygiene sampling data for total hydrocarbons (a composite variable of the major neurotoxic solvents present) were grouped according to 20 uniform, temporally stable exposure zones, which had been defined during plant walk-through surveys. Sampling at the time of the study was used to characterize the few zones for which historic data were limited or unavailable. For each participant, the geometric mean total hydrocarbon level for each exposure zone worked in was multiplied by the duration of employment in that zone; the resulting products were summed over the working lifetime to create the CE variable. The CE variable was divided by the total duration of employment in solvent-exposed jobs to create the LWAE variable. The explanatory value of each participant's LWAE estimate in the regression of simple visual reaction time (a neurobehavioral test previously shown to be affected by chronic solvent exposure) on exposure was compared with that of several other exposure variables, including exposure duration and an exposure variable based on an ordinal ranking of the exposure zones.(ABSTRACT TRUNCATED AT 250 WORDS)

Temporal Variation in Oxygen and Chemical Concentration in a Confined Workspace: The Wastewater Manhole

Abstract Industrial hygiene sampling for oxygen content, combustible gases, carbon monoxide, hydrogen sulfide, and volatile organic chemicals was conducted in manholes of two sewerage collection systems. Sampling results showed periods of sudden atmospheric changes inside the wastewater manhole with decreases in oxygen content and increases in carbon monoxide levels being the most frequently observed events. In addition to the sampling performed, questionnaires were sent to 567 municipalities and 99 (80%) sewerage authorities in New Jersey regarding safety equipment, procedures, and training. Two hundred ninety (42%) of the questionnaires were returned, and generally low levels of employee training and/or written confined space entry procedures were reported by those responding. At the time that this study was undertaken, a confined space standard for public employees did not exist in New Jersey. A Public Employees Safety and Health (PEOSHA) confined space standard was subsequently adopted and became effe...

A Deterministic Mathematical Model for Quantitative Estimation of Historical Exposure

A deterministic mathematical model has been developed for quantitative reconstruction of historical exposure. The model takes into account the causal variables actually responsible for changes in exposure and the interdependence between mean exposures in consecutive time periods. The effects of causal variables are described by step functions. In contrast, statistical modeling, a popular alternative strategy, often employs ad hoc exploratory variables, presumes independence among exposure levels, and invokes linearity or curvilinearity. Changes in exposure-modifying variables used in the deterministic model are identified from plant records. Available industrial hygiene sampling data are employed to estimate model parameters by the method of weighted least squares. The resulting general solution permits reconstruction of past exposure levels for the entire time period of interest, e.g., in a retrospective epidemiologic study. The method is illustrated by using formaldehyde exposure data from the coremakin...

A Deterministic Mathematical Model for Quantitative Estimation of Historical Exposure

A deterministic mathematical model has been developed for quantitative reconstruction of historical exposure. The model takes into account the causal variables actually responsible for changes in exposure and the interdependence between mean exposures in consecutive time periods. The effects of causal variables are described by step functions. In contrast, statistical modeling, a popular alternative strategy, often employs ad hoc exploratory variables, presumes independence among exposure levels, and invokes linearity or curvilinearity. Changes in exposure-modifying variables used in the deterministic model are identified from plant records. Available industrial hygiene sampling data are employed to estimate model parameters by the method of weighted least squares. The resulting general solution permits reconstruction of past exposure levels for the entire time period of interest, e.g., in a retrospective epidemiologic study. The method is illustrated by using formaldehyde exposure data from the coremaking area of a foundry. Mean exposures estimated by the model are found to predict available data well. Using the same data set, the deterministic method is compared with three typical statistical models. The strengths and limitations of the deterministic approach are discussed.

An Exposure Assessment of Industries using Ethylene Glycol Ethers

Abstract Human case reports and animal experiments have shown that ethylene glycol ethers have the potential to cause adverse health effects. The National Institute for Occupational Safety and Health has completed an exposure assessment of industries to determine the extent of occupational exposure to 2-methoxyethanol, 2-ethoxyethanol, and their respective acetates (2-methoxyethyl acetate and 2-ethoxyethyl acetate). This information is useful for assessing the feasibility of additional health studies of glycol ether-exposed workers, and in addition, the results are of interest to the Occupational Safety and Health Administration (OSHA) which has announced its intent to revise the current permissible exposure limits for these four ethylene glycol ethers. This study attempted to quantify human exposures in a variety of industries where these glycol ethers are produced or used as ingredients. Field surveys were conducted at eight different workplaces to collect industrial hygiene samples and obtain informati...