S. Arnold, EH&S LLC, Roswell, GA; C. Kiel, Bowling Green State University, Bowling Green, OH.
Metal removal fluids (MRF) are the largest subcategory of metalworking fluids (MWF). Used in grinding and machining, MRF are aerosolized and create inhalation exposures to large numbers of workers. The health effects of these exposures have been studied over the past decades. Historically, the mineral oil mist PEL/TLV® of 5.0 mg/m3 has been used as a rough surrogate for water dilutable MRF by adapting the 5.0 mg/m3 exposure limit to apply to total particulate mass as determined by gravimetric analysis. Recently, NIOSH and the OSHA MWF Standards Advisory Committee have proposed a much lowered REL/PEL for all types of MRF of 0.4 mg/m3 thoracic particulate mass. Setting new, appropriate occupational exposure limits requires strong exposure assessment data supporting the health effects information. A review of the exposure assessments supporting the health effects studies was done. A tiered system of evaluation was developed based on previously published work. The system scored exposure assessments on a scale of zero (no quantitative exposure information) to four (an ideal exposure assessment). Studies that looked at cancer as the health endpoint of concern had lower scores for their exposure assessment. This generally was due to a lack of demonstration that the sampling strategy used in the retrospective exposure assessment was statistically representative of all the workers. Studies that evaluated respiratory health effects as an endpoint scored higher, but did not achieve scores reflective of robust exposure assessments, limiting their utility in the standard setting process. In many of these studies, the lack of speciation of the aerosol exposures was a significant limiting factor. Exposures to the different types of MRF were often only considered qualitatively. Use of the reviewed studies in determining a new, appropriately protective OEL is limited due to gaps in the exposure assessments supporting the studies.
S. Milz, N. Herial, E. Schaub, Medical College of Ohio, Toledo, OH; K. Smigielski, First Solar, Perrysburg, OH.
From 2001–2003 a small manufacturing company in Northwest Ohio worked to bring a new process to full manufacturing strength. The process utilizes cadmium in the manufacture of commercial solar panels. The facility has maintained compliance with OSHA standards during this time and has established a statistically-based process control system to monitor cadmium levels throughout the facility. The goal for this monitoring system is to use engineering controls to keep emissions at nondetectable levels for all production operators with action limits established well below the required OSHA standard. Toward this end, 904 area air samples and 175 personal air samples were collected throughout the facility. The sampling data was provided to the Department of Public Health at the Medical College of Ohio for statistical analysis. The industrial hygienist at the manufacturing facility provided the data already categorized by task. The area air sampling data was analyzed for time trends by individual year and for all years combined. The personal air samples were used to perform exposure assessments for each task using the strategy of the AIHA publication “A Strategy for Assessing and Managing Occupational Exposures” (Mulhausen, Damiano, 1998). Again the data was initially analyzed by individual sampling year and for all years combined. Based on this data, engineering controls that include HEPA filtration systems have been proven effective in the control of emissions. Currently, several areas meet the emission goal using engineering controls only. A few areas require engineering controls and personal protective equipment. Continuous improvement activities are driving more data collection in these few areas in order to move them toward engineering controls only, eliminating the need for personal protective equipment.
D. Fleming, NIOSH, Cincinnati, OH; A. Markey, Westat, Rockville, MD.
Retrospective chemical exposure assessment for carbon tetrachloride and benzene at the DOE Hanford site has been developed as part of a multisite case-control study of leukemia among radiation exposed workers. The overall study purpose is to explore the relationship between low-level radiation exposure and death from leukemia, while accounting for potential confounding by internal radiation and chemical exposures. A job exposure matrix was created from work histories, process descriptions, chemical inventories, and monitoring records. Less than a dozen air samples for these agents were identified. Examination of the process documents at Hanford from 1944 to 1996 identified uses of benzene and carbon tetrachloride. Potential benzene exposure was limited to 8 activities. The potential for carbon tetrachloride exposure was identified in 13 activities. Of 908 chemical inventory records for Hanford, 2 reported benzene, and 8 reported the presence of carbon tetrachloride. Work histories for the 495 Hanford workers were extracted from available data at NIOSH which was supplemented from information from other employment and medical records from Hanford. Job titles, organization codes, and buildings were identified for the time periods worked. The three most frequent job titles were: power operator, clerk, and engineer. The percentage of person-years with an identified job title is 95.6%, with an organization code is 81.7%, and with an identified building is 62.8%. Comparison of these three factors allowed imputation of the missing values. Categories of exposure opportunities to these two chemicals were derived for the epidemiologic analysis.
A. Markey, Westat, Cincinnati, OH; D. Fleming, NIOSH, Cincinnati, OH.
In support of a case-control epidemiology study of leukemia and external ionizing radiation at five U.S. Department of Energy sites, historical chemical exposure strategies have been developed for worker solvent exposure, a potential confounding factor. The size of the Savannah River Site population (207 workers) allows for an extensive exploration of potential chemical solvent confounders during the study period of 1951 to 1996. An exposure assessment strategy was developed to determine the levels of confounding by chemical solvent exposures, concentrating on benzene and carbon tetrachloride. The 207 study subjects have 86 unique job titles with the most frequent being mechanic, operator, patrolman, and engineer. The initial step in the exposure assessment process looked at potential exposures linked by job title, work location, and the time period in which the exposure was generated taking into consideration changes in personal protective equipment use, engineering controls, and removal of chemicals from the workplace. In order to implement this assessment strategy, work histories for each study subject were compiled using available information from electronic images of medical, personnel, and health physics records. A job exposure matrix (JEM) detailing the exposures to chemical solvents was developed through a comprehensive review of process descriptions, chemical inventories, and industrial hygiene monitoring data for each combination of site, work location, job title, and time period for each individual study location. After finalizing the JEM, the job title histories have a 93% completion rate (3331 of 3594 person-years); the division descriptor has a 95% completion rate (3405 of 3594 person-years), and the location descriptor has a 64% completion rate (2296 of 3594 person-years ). Comparison of these three factors allowed imputation of missing values. Categories of exposures can be assigned with these different methods of examining chemical solvent use at the site.
J. Hornsby-Myers, NIOSH, Morgantown, WV; K. Jones, U.S. Coast Guard and University of North Carolina, Chapel Hill, NC.
Workers in many outdoor occupations move about frequently during a typical day of work. Certain workers, such as those on U.S. Coast Guard (USCG) security patrols, are particularly mobile. The National Institute for Occupational Safety and Health (NIOSH) designed and developed a prototype exposure monitoring system which combines geographical location with up to four real-time sensors and outputs the information to a user-friendly interface. By linking worker location throughout the workday to exposure levels from real-time monitors, Local Positioning System (LPS) units with software processing of data identify and document where to focus exposure analysis and control efforts. Post-processing of LPS data enables researchers, regulatory inspectors, and industry safety and health personnel to map exposure intensity and location, reveal hot spots to identify sources, and provide exposure intensity distributions.
In this study, the LPS was field-tested during USCG security patrols along the Houston Ship Channel. By linking the LPS to a direct reading 5-gas monitor, position information was fixed with contaminant levels for each patrol. The field test was conducted over a six-day period in August 2003 and at different times of the day. Statistical information, maps showing peak concentrations, frequency, and time-weighted averages along the route of the patrol were created using software developed by NIOSH for the LPS. Results showed sulfur dioxide ranged from none detected to 0.2 ppm, hydrogen sulfide from none detected to 1.3 ppm, and volatile organic compounds from none detected to 5.5 ppm.
The information obtained from the LPS allows safety professionals to better understand exposure information and focus controls where they may be more aptly applied. Modular software that enhances the utility of the system as a valuable tool to researchers for improved identification, documentation, analysis, and control of exposures was developed to download the data collected from the prototype LPS.
J. Koehn, B. Kuntz-Johnson, JK Inc., Houston, TX.
A workplace exposure assessment project was initiated for a pipeline transportation company during 2002 with continuing annual work during 2003–04. Due to recent and continuing mergers and acquisitions involving changing field sites, corporate safety personnel for the crude oil and conventional products/LPG areas requested consulting assistance for a three year baseline industrial hygiene assessment project.
The project scope of work involved the following: occupational exposure monitoring for full shift hydrocarbon exposures; short-term work task monitoring for benzene and/or hydrocarbons; personal noise dosimetry; and field site surveys for the presence of asbestos-containing materials (ACM), lead-based paint, sound pressure levels, and naturally occurring radioactive materials only at LPG locations. Representative personal monitoring by job position including operators, technicians, gaugers, and truckdrivers was conducted.
Corporate safety personnel identified specific field locations for both crude oil and conventional products/LPG to be assessed on an annual basis. A Certified Industrial Hygienist (CIH) with either an industrial hygienist or technician completed the scheduled site visits. The sampling strategy was appropriately revised and implemented at each field site and all personal and bulk samples were analyzed by a local AIHA accredited laboratory. Digital photographs were documented of “suspect” materials and/or site locations requiring further investigation.
An annual report was prepared summarizing all the laboratory analytical data. Separate tables for each type of chemical and/or physical hazard were documented for each facility field site location. A summary report was also appended for the collected project data with both general and specific recommendations. Presentations were made at annual meetings of the safety representatives and any follow-up monitoring or site investigations were outlined by the client. Further industrial hygiene consulting work activities were identified including ergonomic workstation assessments, performance of negative workplace exposure assessment, and airborne fiber monitoring for ACM pipe coating removal.
L. Taylor, CDC/NIOSH Harvard School of Public Health, Boston, MA; K. Ashley, CDC/NIOSH, Cincinnati, OH; R. Jones, CDC/NCEH, Atlanta, GA; J. Deddens, CDC/NIOSH University of Cincinnati, Cincinnati, OH.
This study further evaluated an electroanalytical field-portable instrument which rapidly analyzes venous blood lead levels in individuals. The instrument, which employs anodic stripping voltammetry (ASV) to measure lead in blood, was used on blood samples from an Andean worker population (almost entirely male) at an elevation of ~3800 meters in Peru. The portable ASV instrument was evaluated utilizing paired samples from 243 employee volunteers. Each worker donated two venous blood samples, one of which was analyzed by the ASV device, and the other by a reference analytical method, graphite furnace atomic absorption spectrometry (GFAAS). Hemoglobin levels of the workers’ blood samples were also measured. According to the GFAAS results, the mean blood lead concentration measured was 46(±16) µg/dL; this was significantly greater than the mean ASV measurement of 32(±11) µg/dL (paired t-test; p<0.0001). The accuracy of the ASV estimation decreased as the measured blood lead concentration increased. The mean hemoglobin concentration in this Andean worker cohort was 17.3 g/dL, which contrasts with the mean hemoglobin level of 15.3 g/dL in U.S. males living near sea level. Hemoglobin levels were unrelated to blood lead concentrations (r2 = 0.00905; p = 0.143). The ASV evaluation results from this investigation, which was carried out at a very high elevation, were significantly different from the previous study, which was conducted near sea level. The exact causes for the discrepancies between the portable ASV results from the two studies are unclear, but are thought to be related to differences in blood chemistry between the Midwestern United States and Peruvian Andes worker cohorts. Analytical results from portable ASV measurement of blood lead levels in extremely high-altitude populations should be treated with caution.
J. Cocker, P. Akrill, K. Jones, Health & Safety Laboratory, Sheffield, United Kingdom.
This describes a method for the extraction and analysis of m-xylylene diamine (m-XDA) (CAS 1477-55-0) from the urine of exposed workers. XDA is used as a hardening agent for epoxy resins. Its main health effect is irritancy although limited human data suggest it may be a potent skin sensitiser. The method uses GC-MS for a sensitive and specific determination of occupational exposure.
Urine samples are acid hydrolysed and then extracted using diethyl ether followed by derivatisation with heptafluorobutyric anhydride. The derivatised extracted is then injected into the GC inlet by a splitless injection. Detection is by negative chemical ionisation using m/z 508 for m-XDA and m/z 585 for the internal standard ethylene dianiline.
The method was linear over the range 0–400 nmol/l, with a detection limit of 5 nmol/l. The coefficient of variation at ~50 nmol/l was <20%. m-XDA levels in spiked urine showed no degradation when stored at room temperature, at ~4°C and at ~-20°C for at least 7 days. No m-XDA was found in urine from nonoccupationally exposed people (n = 10).
m-XDA levels in 244 pre- and 261 post-shift urine samples of 42 exposed workers were analysed, and m-XDA levels in the range ND–13.93 µmol/mol creatinine (mean 0.418, geomean 0.121) were measured for pre-shift samples and m-XDA levels in the range ND–12.61 µmol/mol creatinine (mean 0.679, geomean 0.1528) were measured for post-shift samples. m-XDA levels in 20 acid hydrolysed samples from workers exposed to m-XDA were significantly higher (p<0.0001) than samples that had not undergone any hydrolysis. p-XDA was also extracted and detected in spiked urine, although none was found in samples from workers.
The method described here is a sensitive, robust method suitable for the detection of m-XDA in the urine of exposed workers.
J. Roh, K. Park, C. Kim, H. Kim, H. Kim, Yonsei University College of Medicine, Seoul, Republic of Korea.
Toluene diisocyanate (TDI) is widely used in the production of polyurethane foam, as well as in the formulation of polyurethane paints and coatings. The commercial material is generally a mixture of 2,4-TDI and 2,6-TDI. Studies indicated that exposed workers had elevated levels of urinary toluene diamines (TDAs), but a correlation between levels of TDA in urine and airborne concentration of TDIs in workplace could not be established. This study was conducted to investigate the correlation between levels of urinary TDAs and airborne concentration of TDIs, which are being sampled with open cassette holder (OCH) and the modified 2-piece cassette holder (2-PCH). The sampling was executed on the 22 workers from the factory where operated painting work by using polyurethane paints. This study identified the personal character of workers by using the questionnaire and analyzed TDIs from 44 samples each in the middle of morning and afternoon and TDA from the 17 workers by taking their urine. As a result of analysis, the concentration of TDIs in the air is higher on 2-PCH than OCH. There was no significant difference in the concentration of urinary TDA by general characteristics. The concentration of TDI in the air had significant correlation with the concentration of urinary TDA no matter what kind of sampling method was used, but the sampling technique by 2-PCH had more correlation than OCH. As a result of this experiment, the concentration of TDI by sampling with the each cassette holder has shown a significant relation with the concentration of urinary TDA.
K. Hanley, B. Curwin, M. Petersen, NIOSH, Cincinnati, OH; W. Sanderson, University of Iowa, Iowa City, IA.
1-Bromopropane (1-BP) has been marketed as an alternative for ozone depleting solvents and suspect carcinogens and is in aerosols, adhesives, and solvents used for metal, precision, and electronics cleaning. Toxicity of 1-BP is poorly understood, but it may be a neurologic, reproductive, and hematologic toxin. Sparse exposure information prompted NIOSH to conduct an exposure assessment using air sampling, exhaled breath, and urinary metabolites. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving removal of bromide from the propyl group. One research objective is to evaluate the utility of urinary bromide analysis for assessing 1-BP exposure using a relatively inexpensive method commercially available. Complete 48-hour urine specimens were obtained from 30 workers on 2 consecutive days at facilities using 1-BP adhesives to construct polyurethane foam seat cushions and from 7 unexposed controls. All of the workers’ urine was collected into composite samples representing 3 daily time intervals: at work, after work but before bedtime, and upon wake-up. After collection, urine aliquots were dispensed into acid-rinsed Nalgene® bottles and analyzed for bromide (Br) by inductively coupled plasma-mass spectrometry. Full-shift breathing zone samples were collected for 1-BP on Anasorb-CMS sorbent tubes and analyzed by gas chromatography-flame ionization detection via NIOSH method 1025. Breathing zone concentrations of 1-BP ranged from 45–200 ppm for adhesive sprayers and from 0.8–60 ppm for other jobs. For sprayers, urinary Br concentrations ranged from 77–542 mg/g-creatinine (cr) at work, from 58–308 mg/g-cr after work, and from 43–672 mg/g-cr in wake-up samples. Overall, urinary Br concentrations for sprayers were substantially more than for the nonsprayers and controls, with geometric means of 166, 38, and 3.8 mg/g-cr, respectively. This study demonstrates that urinary elimination is an important excretion pathway for 1-BP metabolism and bromide may be a useful indicator of exposure.
A. Fedorowicz, CDC/NIOSH, Morgantown, WV; H. Singh, E. Demchuk, CDC/NIOSH and West Virginia University, Morgantown, WV.
Allergic contact dermatitis is a common work-related skin disease that often develops after repetitive skin exposures to a sensitizing chemical. A variety of animal and human experimental assays have been suggested to assess the skin sensitization potential. The introduction of the murine local lymph node assay (LLNA) with its quantitative endpoint for skin sensitizing potency has provided continuous scale suitable for developing quantitative structure-activity relationships (QSARs) of skin sensitization, which relate physical-chemical properties of chemical compounds to their sensitization potential. However, at present many LLNA results are mostly reported using a dichotomous scale (+/-), which is consistent with the scale of guinea pig and human tests, which have been widely used in the past. Therefore, in this study only a dichotomous version of the LLNA data was used to develop QSAR models of skin sensitization. Using statistical methods, physical-chemical properties of chemicals, called molecular descriptors, were tested for their ability to predict the skin sensitization potential. A few of the most informative descriptors were subsequently selected to build QSAR models of skin sensitization with high prediction rates.
D. Lillquist, B. Craig, University of Utah, Salt Lake City, UT.
If the ventilation systems are functioning improperly or are poorly designed in indoor firing ranges, high concentrations of airborne lead are typically present. Low cost temporary ventilation baffle mock-ups can be used to test proposed improvements to reduce airborne lead concentrations. Baffles were installed in an indoor shooting range to increase air velocities and modify airflow patterns in the shooters’ breathing zones in an attempt to reduce personal exposures to airborne lead. Ventilation measurements and personal air sampling were conducted prior to and after the baffles were installed. The mean air velocity was increased from 6 to 13.4 feet per minute at the shooting line, and increased to 19.4 feet per minute at the gun position. Airborne lead concentrations were reduced from 645.2 to 30.9 µg/m3 (8-hr time-weighted averages 67.2 to 2.3 µg/m3, respectively). Although the mean velocities were much lower than the recommended air velocity of 50 feet per minute, significant reductions in airborne lead exposures were achieved. Other necessary improvements to the range were also identified, such as relocating the exhaust ventilation ducting to the bullet trap and improving the distribution of air across all shooting booths; however, the benefits of increased air velocity were observed prior to the additional investments.
A. Afshari, J. Antonini, S. Stone, G. Fletcher, V. Castranova, D. Frazer, NIOSH, Morgantown, WV.
Epidemiological studies suggest that the long-term inhalation of welding fumes may lead to lung disease, neurotoxicity, and cancer. The fume generated during the welding process has been shown to consist of ultrafine particulates (e.g., chromium and nickel) as well as gases (e.g., ozone, nitrogen oxide, and carbon monoxide). Laboratory studies are needed to further investigate the adverse effects of exposure to welding fume. The objective of this study was to design an inhalation exposure system to be used in the evaluation of the toxicity of welding fume in rats. To ensure continuous delivery of the welding fumes without interruption of exposure, an automated computer-controlled robotic welder has been constructed. The robotic torch is combined with a programmable head stock capable of welding at a continuous rate of 30 cm/min for 6 hr/day. A flexible exhaust trunk is attached to the robotic arm and is used to collect the generated fume from the welding arc region and transport it to the animal chamber. Initial characterization studies of the fume generated with this system indicate that aerosol size characteristics (less than 1 micron) and ozone levels (0.24 ppm) are comparable with welding fumes formed in the workplace. With the development of this novel robotic welding fume generation system, we will be able to address some of the unanswered questions concerning the heath effects of welding fumes.
P. Raynor, University of Minnesota, Minneapolis, MN.
Fibrous filters collect airborne particles in respiratory protection, air pollution control devices, and HVAC systems. Developing filters that have higher efficiency at the same pressure drop could offer better protection for workers. Currently, most filters are made from fibers with circular cross sections. However, fiber manufacturers can produce synthetic fibers with irregular shapes. The purpose of this research was to use numerical modeling to evaluate the potential for changes in fiber shape to improve filter performance. Airflow around single fibers with circular, elliptical, tri-lobal, and eight-lobed cross sections was modeled in two dimensions using computational fluid dynamics (CFD) software. The simulations included differences in fiber orientation and packing density. In addition, the movement of particles of different sizes was superimposed on the airflow. The modeling suggested that modest improvements in filter performance were possible with changes in fiber shape. Although some fiber shapes and orientations provided higher single fiber efficiency for large particles by the impaction and interception filtration mechanisms, those improvements were generally offset by increases in fiber drag, which is associated with pressure drop. When the simulated fibers collected small particles by diffusion, elliptical fibers exhibited slightly better performance in some orientations than the circular fibers. For example, CFD modeling for fibers with a packing density of 0.05 and particles with a Peclet number of 10,000 showed that an elliptical fiber oriented parallel to the airflow had a single fiber efficiency of 0.00823, whereas a circular fiber had an efficiency of 0.00676. At the same conditions, the drag across the elliptical fiber was 11% lower than the drag across the circular fiber. The tri-lobal and eight-lobed fibers did not show substantial differences from the circular fibers in most cases.
D. Decker, P. Moore, Shaw E&I, Centennial, CO.
The use of a 3/4-acre movable containment structure to control public exposure to airborne contaminants at a Superfund site created a situation where concentrations of silica, ammonia, and carbon monoxide frequently exceeded the respective PEL/TLV® inside the structure. Workers inside the structure break up and remove a soil, cement, and flyash monolith containing radiological contamination. The structure was designed with an exhaust filtration system to control dust and equipment exhaust emissions created during excavation. Changes in operational techniques resulted in more and different pieces of equipment used for excavation. The fine composition and silica content of the monolith contributed to creating a situation where workers were required to wear respiratory protection and the exhaust system filters were frequently overloading. Engineering control solutions were sought to control the silica generation and vehicle emissions. Initially, a modified fire hose was used to suppress dust. Dust suppression was moderate but the excess water created mud and an opportunity for slips and falls. Alternative dust suppression methods were evaluated. A fog cannon was designed to reduce dust generation and silica exposures. Emission control devices were retrofitted to diesel powered equipment. The fog cannon reduced silica concentrations in the structure by 77%. The fog cannon distributes less water more uniformly reducing slippery surfaces in the excavation and on equipment. Ammonia concentrations were reduced by 50% because there is less water applied to the ammonium salts in the monolith. Containment structure filter replacement was reduced by a factor of 2. Equipment emission controls reduced carbon monoxide concentrations by 83%, to levels below the PEL/TLV®. The combination of the fog cannon and equipment emission controls reduced concentrations of silica, ammonia, and carbon monoxide sufficiently so that respiratory protection was no longer required resulting in better visibility, less heat stress, and cost savings.
P. Hogan, Zellweger Analytics Inc., Lincolnshire, IL.
Delegates will gain a practical and insightful overview of the current communications protocols, field bus systems, and control networks that can be deployed within industrial environments for life safety sensing, alarm, and controls. An independent, hands-on review of the relative strengths and limitations of analog 4-20mA, HART, ProfiBus, ModBus, LONWorks, Ethernet, DeviceNet, and other protocols will be presented. Issues such as cost of installation, speed of response, ease of configuration, redundancy and connectivity with a broad range of control racks, Fire and Gas systems, PLC, DCS, and SCADA systems will be discussed. Users will gain a clear insight on how to design, cost up, install, commission, and test their communication network for typical industrial safety applications. Actual end user examples will be shared that explain how best to design robust alarm and annunciation scenarios, monitor faults, and develop interactive human machine interfaces that are fit for purpose. A roadmap summary indicating imminent trends in alternative communication systems notably wireless, “less-wire”, and Power over Ethernet will equip busy life safety engineers with a fast track awareness of the important benefits to be gained with these emerging technologies.
C. Manning, S. Green, J. Hearing, Assay Technology, Pleasanton, CA.
In recent years, molds have been increasingly implicated in indoor air quality complaints ranging from property damage to unpleasant odors and toxic exposures arising from their chemical by-products. Several researchers have conducted studies in which a family of microbial volatile organic compounds (MVOCs) has been identified as the product of mold metabolism in a process similar to fermentation. Although the identities and quantities of specific MVOCs arising from mold metabolism vary somewhat with species and environmental conditions, a strong family resemblance has been found among MVOCs which has led to their characterization by chemical air sampling technologies.
A majority of MVOCs, predominantly oxygenated organics, e.g. saturated and unsaturated aldehydes and alcohols, may be sampled on traditional air sampling media and analyzed by gas chromatography. While several sorbents, desorption methods, and chromatography systems have been recommended for different MVOCs, the goal of this study was to devise a single sampling method capable of collecting and retaining a large number of MVOCs coupled with an analytical method capable of analyzing as many components as possible in a single chromatography scan. In this study, multiple MVOCs were generated in a dynamic chamber and sampled together on a diffusive sampler utilizing activated carbon followed by desorption with a mixture of benzyl alcohol and carbon disulfide. Method evaluations were performed as outlined in ANSI and ASTM protocols. Individual MVOCs were metered via syringe pump into a dynamic flow system generated via a Miller-Nelson controller. Active sampling methods were utilized as the reference comparison for all studies. When this method was coupled with analysis via gas chromatography on dual 60m capillary columns of differing polarity, more than 20 distinct MVOCs could be sampled, identified, and analyzed.
L. Saarinen, T. Tuomi, T. Johnsson, K. Reijula, Finnish Institute of Occupational Health, Helsinki, Finland.
It is frequently pointed out that mycotoxins present in bulk materials infested with toxigenic fungi are carried indoors by fungal spores. It follows that mycotoxins in indoor environments are inhaled with dust particles containing the fungal spores. To test this theory, bulk samples of moldy interior surfaces were analysed by HPLC-MS/MS concomitantly with settled dust for the presence of 12 trichothecenes. Samples were collected from four work places in southern Finland, including two university buildings and two children’s day-care centers. The samples from one site were tested with trichothecene-sensitive feline fetus lung cell line, and with chemical analysis. All the examined sites had a history of health complaints, likely connected to mold exposure.
Diacetoxyscirpenol and T-2 toxin were the most prevalent trichothecenes found in the samples. Apart from these, 3-acetyl-deoxynivalenol, T-2 tetraol, verrucarol, and roridine A were occasionally present. Satratoxins G and H were also found at two of the examined sites, both of which were contaminated with Stachybotrys chartarum. Biological analysis with the feline fetus lung cell line correlated with the presence of T-2 toxin, but not with verrucarol.
Mycotoxin concentrations per fresh weight of extracted material were consistently highest in dust. The presence of individual toxins in the dust reflected the mycotoxins found in the bulk materials. When the goal is to investigate the presence of mycotoxins in indoor environments, collection of the deposited dust should be part of the research procedure. Also, air sampling of mycotoxins to filters should be considered, as this reveals mycotoxin concentrations in the ambient air. However, judging from the present results, the collection time should be in the range of days-or even weeks-rather than hours.
D. Sahai, Construction Safety Association of Ontario, Etobicoke, ON, Canada.
The Construction Safety Association of Ontario in conjunction with other safety associations developed a chart to communicate in a clear and comprehensive way mold control procedures recommended by the U.S. Environmental Protection Agency. The chart indicates how mould growth can be prevented for various kinds of material within 24–48 hours of water damage and also provides general advice on remediation. Users begin at the center ring of the chart, and proceed one step, or one ring, at a time.
In the first ring, identify the material you are concerned about. In the next ring, find out what actions to take within the first 24–48 hours of clean water damage. Actions are spelled out under the “Action within 24–48” hrs column outside the chart. Proceed to the next ring if mould growth is apparent and more than 48 hours have elapsed since water damage. Determine whether the contaminated area is less than 10 square feet, between 10 and 100 square feet, or greater than 100 square feet. Proceed to the next ring and follow the clean-up method indicated for the size of the contaminated area. Methods are spelled out under the “Clean-up Methods” column. In the next ring, decide on the level of personal protective equipment (PPE) required. These requirements are explained in the “PPE” column. Finally, establish from the outermost ring whether containment is necessary and, if so, whether it must be limited or full. Each is spelled out under the “Containment column.”
A summary of basic mould remediation procedures, the chart is extremely useful as a quick and simple training document for health and safety professionals, health and safety committee members, and workers concerned about mould remediation.
J. Park, J. Cox-Ganser, C. Rao, K. Choe, NIOSH, Morgantown, WV.
Good sampling strategies for measuring airborne fungi require information on reproducibility as well as spatial and temporal variability. We examined variance components and reproducibility of airborne fungal measurements. We measured airborne culturable fungi (colony counts) and spore levels with single-stage multi-hole impactors loaded with malt extract agar plates and Air-O-Cell cassettes, respectively, at 30 locations in an office building with a history of water damage. Simultaneous duplicate samples were collected at 15 of those locations. We sampled at 4 time points (AM and PM on Monday and Thursday) within a week during a dry summer. Random models were used to analyze spatial and temporal variability of fungal levels and reproducibility (coefficient of variation = CV) of the duplicates. The temporal variability (within-location geometric standard deviation, GSDw = 1.44) of total colony counts was about 1.3 times higher than spatial variability (between-location GSDb = 1.11). The temporal variability (GSDw = 1.87) of total spore counts was about two-fold higher than spatial variability (GSDb<1.01). For colony counts, the temporal to spatial variance ratio was highest for Penicillium/Aspergillus (Pen/Asp) species (ratio = 1.8). For spore counts, the temporal to spatial variance ratio for basidiospores was highest (3.4), followed by Pen/Asp species (2.6), Cladosporium (2.2), and ascospores (2.1). Duplicate analyses showed that reproducibility was better for total colony counts (CV = 10%) than for total spore counts (CV = 20%). Pen/Asp species in colony counts (CV = 25%) and spore counts (CV = 40%) were the least reproducible of all identified fungal taxa. Given the high observed temporal variability of fungal measurements, a single sample at one time point provides a very limited assessment of exposure to airborne fungi in a given location within an office building. Random sampling and analytical error significantly contributed to the total variance of airborne fungal measurements, especially for Penicillium/Aspergillus species.
C. Chen, K. Chang, T. Lin, C. Hsu, Y. Lee, National Taiwan University, Taipei, Taiwan, Republic of China; Y. Kuo, Chung Hwa College of Medical Technology, Tainan, Taiwan, Republic of China; C. Lai, Chung Shan Medical University, Taichung, Taiwan, Republic of China.
Indoor air cleaners, in addition to the HVAC system, are often used to remove airborne particles in order to reduce allergic reactions of people suffering from respiratory problems. In the present study, two types (ESP and filter) of commercially available indoor air cleaners were acquired from local departmental stores for testing collection efficiency, pressure drop across the air cleaner, and energy consumption in a bench test system. Polydisperse aerosol particles were generated using a constant output aerosol generator and an ultrasonic atomizing nozzle. Aerosol outputs from both generators were then neutralized by using a radioactive source (Kr-85) to neutralize the aerosol particle to the Boltzmann charge equilibrium. The main aerosol size-spectrometers were a Scanning Mobility Particle Sizer and an Aerodynamic Particle. These air cleaners were also used in a small meeting room similar to the ANSI/AHMA AC-1-2002 air cleaner certification chamber to measure the Clean Air Delivery Rate (CADR), but without the humidity and temperature conditioning. The decay rates were measured by using real-time aerosol instruments and a mini infrared analyzer.
The results showed that aerosol penetration through ESP- or filter-type air cleaners increased with increasing face velocity (corresponding to flow rate) for submicrometer-sized particles. For micrometer-sized particles, the aerosol penetration through filter-type air cleaners decreased with increasing face velocity due to higher inertial impaction. The decay constants are strongly aerosol size dependent. Particles near the most penetrating size (about 0.3 µm) had the lowest decay constant, while particles larger or smaller than 0.3 µm all showed higher decay constants. Devices equipped with options of different speeds probably should operate under the highest flow rate to obtain the highest decay rate, and thus highest CADR. In general, ESP air cleaners perform better than filter-type air cleaners if both CADR and energy consumption are considered.
Posted May 30, 2004