H. Kim, Dongguk University, Gyeonggi-do, Republic of Korea; C. Kim, J. Won, J. Roh, Yonsei University, Seoul, Republic of Korea; B. Cha, Yonsei University, Gangwon-do, Republic of Korea; K. Lee, Ajou University, Gyeonggi-do, Republic of Korea.
This study was performed to investigate the changes of urinary thiodiglycolic acid (TDGA) concentration in workers exposed to vinyl chloride monomer (VCM) according to the time of urine sampling. The concentration of airborne VCM and urinary TDGA were measured for 31 workers employed at a VCM manufacturing factory in Korea. Urinary TDGA was sampled a total of four times: (1) before the start of work after three days off (TDGA1); at the end of one working day (TDGA2); before the start of work after one working day (TDGA3); and at end of work after four consecutive working days (TDGA4). Urinary TDGA in 30 control workers who were not exposed to airborne VCM were sampled at the end of one working day shift. The urinary TDGA levels were 0.18±0.27 mg/g creatinine in control workers and 0.22±0.44mg/g creatinine in TDGA1, showing no significant difference (p=0.70). The concentrations of TDGA2, TDGA3, and TDGA4 were 0.43±0.62, 0.77±1.06, and 0.92±1.07mg/g creatinine, respectively, which indicated gradual increase of concentration by the sampling time (p=0.02). In correlating airborne VCM and urinary TDGA to evaluate exposure dose per day, TDGA3 concentrations showed the significant correlation (R2=0.42) with 8-hr time-weighted average airborne VCM concentration. It is possible that sampling before the start of work after one working day (TDGA3) can be applied as a useful biological index to evaluate exposure dose of airborne VCM during one previous day shift.
L. Blum, E. Bakowska, J. Schemmer, NMS Labs, Willow Grove, PA.
Uranium is a weakly radioactive element that occurs naturally in the environment. Every person ingests and inhales natural uranium daily from the air, water, and soil. The amount varies depending upon the natural levels found in the area in which one lives and the source of food and water one consumes. Consequently, people have some level of uranium in their body. Once absorbed, uranium is eliminated primarily in the urine. The normal range of uranium in urine is listed as less than 0.1 mcg/L. Natural uranium consists of 0.72% of 235U isotope and 99.27% of 238U isotope. Depleted uranium (known as DU) is uranium that is 40% less radioactive than natural uranium, while retaining identical chemical properties. Depleted uranium is used in armor-piercing munitions, in enhanced armor protection for some Abrams tanks, and in stabilizers of airplanes and boats, among other civilian uses. The 235U percentage in individuals exposed to DU is in the range of 0.20%-0.33% of total uranium. The biological monitoring of total uranium levels in urine does not provide information about potential exposure to DU. Only the measurement of the isotopic ratios of 235U and 238U can determine the exposure to DU. Twenty-five samples from suspected DU exposures were analyzed by ICP/MS for 235U and 238U. Since levels of both isotopes were extremely low, we determined the total uranium. We found that if the urine contains extremely low levels of total uranium (usually below 0.5 mcg/L), the measurements of the isotopic ratios were impractical. We propose a two-tier measurement. First, establish the concentration of the total uranium. Then, only if the total uranium exceeds the threshold of 0.5 mcg/L should 235U and 238U isotopic ratios be measured.
J. Gromiec, Nofer Institute of Occupational Medicine, Lodz, Poland.
For a certain group of rapidly acting compounds that exert irritant effects, the ceiling concentrations that should never be exceeded during an 8-hr shift are established as occupational exposure limits (OELs). Regarding such substances, the level of exposure is more important than the dose absorbed during the work shift. The most appropriate method of testing compliance with ceiling limit values is one employing direct-reading, real-time devices. Such devices, however, are possible for some compounds only; furthermore, the compounds in question should be present in the form of gases or vapors. Covering the entire work shift with short-term samples is impractical. The purpose of the study was to develop an air sampling procedure for testing ceiling compliance based on short-term grab samples. Variable concentrations using hexylene glycol as the test substance were generated dynamically in an experimental chamber for 8 hr. Air samples from the chamber were collected every 3 min by a gas-tight syringe. In addition, consecutive 15-min charcoal samples covering 8 hr were collected. All the air samples were analyzed by gas chromatography. The tests were designed to obtain sets of concentration data of differentiated variability, with some peaks exceeding the ceiling value but average concentrations well below the limit. The variation of the results and distribution parameters appeared to be highly dependent on the sampling or averaging time. Longer averaging time narrows the concentration range, thus decreasing the determined peak concentrations, which influences the possibility to confirm noncompliance. The sampling strategy has been proposed based on the experimental results. Grab samples of up to 15 min are to be collected at regular time intervals, depending on the expected variations in concentration. The proposed strategy has been validated by field measurements and statistical analysis. It may be applied in situations where direct-reading instruments are not available.
J. Park, J. Cox-Ganser, NIOSH, Morgantown, WV.
An observational index of mold and dampness was previously correlated with building-related respiratory symptoms, but its correlation with concentrations of microbial agents was not examined. In three public schools, building engineers completed a visual and olfactory assessment sheet for 221 rooms. They scored water stains, visible mold, mold odor, water damage, and wetness by the size of affected area on seven room components: walls; floor; ceiling; windows, heating, ventilation, and air conditioning (HVAC) units; pipes; and furniture. We computed a mold/dampness score for each room by first averaging the room component scores for each mold/dampness-related factor and then summing these averages over the five factors. We categorized the rooms into high- and low-score groups based on the median of the scores. Measured indices included the moisture content of room components and floor dust concentrations of culturable fungi and bacteria, β-D-glucan, and ergosterol. We compared the concentrations of microbial agents and the maximum value of the moisture content measurements on the multiple room components in the two groups using multiple regressions, adjusting for schools and floor of building. The high-score group of rooms showed higher concentrations of (1) total culturable fungi (least squares means: 1.34×105 vs. 0.74×105 colony forming units (cfu)/g dust; p=0.01); (2) total culturable bacteria (3.42×106 versus 1.62×106 cfu/g dust; p<0.01); (3) total gram-positive bacteria (1.83×106 vs. 0.69×106 cfu/g dust; p<0.01);(4) total gram-negative bacteria (1.96×105 vs. 0.87×105 cfu/g dust; p=0.01); (5) β-D-glucan (63.62 vs. 56.66 ng/mg dust; p>0.1); and (6) ergosterol (1.61 vs. 1.38 ng/mg dust; p>0.1). The high-score group also showed a higher moisture content (208 vs. 162; p<0.01) compared to the low-score group. Inexpensive visual and olfactory observations correlate with industrial hygiene quantitative measures of dampness and microbial burden, which can motivate dampness remediation in the presence of building-related health effects.
L. Naeher, J. Rebholz, K. Merry, K. Mordecai, The University of Georgia, Athens, GA; P. Coaquira, Arequipa Ministry of Health, Arequipa, Peru; M. Aguilar, M. Villalobos, Asociación del Aire Ambiental, Lima, Peru.
This occupational exposure assessment was done in Arequipa, Peru, in summer 2004. The objective was to measure occupational exposures at breathing level to particulate matter (PM2.5 and PM10) and carbon monoxide (CO) in a range of commercial and industrial locations (n=19) in Arequipa, during periods of high and low industrial productivity or commercial activity. Nine restaurant sites were sampled to measure exposures as a result of cooking. Seven commercial facilities were sampled including two brick factories, a cement factory, textile and nylon factories, and two leather factories. Finally, two saunas and a welding shop were monitored. Carbon dioxide (CO) and particulate matter (PM) data were collected using two CO measurers (Langan Products Inc., model T15v and Draeger Safety Inc., model PacIII) and two DustTrak aerosol monitors (TSI Inc., model 8520), collecting PM2.5 and PM10 data. Each site was sampled for 15 min during 3 to 4 separate periods of the day when emission sources (if present) were on and human exposures were expected to be highest. When possible, the sample sites were also monitored during periods of low or no emissions, to collect ambient or background PM and CO levels. Peak 30-sec occupational exposures to PM2.5 and CO were highest in a brick factory (CO = 11.1 ppm; PM2.5 = 12.1 mg/m3); a chicken restaurant (CO = 27.9 ppm; PM2.5 = 0.4 mg/m3); a traditional restaurant (CO = 35.7 ppm; PM2.5 = 16.1 mg/m3); a bakery (CO = 3.2 ppm; PM2.5 = 1.8 mg/m3); and a welding workshop (CO = 4.4 ppm; PM2.5 = 1.1 mg/m3). The occupational CO and PM2.5 levels observed in several of the commercial and industrial sites are clearly sufficient to adversely impact worker health and warrant further investigation.
P. Middendorf, NIOSH, Cincinnati, OH; L. Keller, University of Pittsburgh, Pittsburgh, PA; C. Simmons, Boelter Associates, Inc., Chicago, IL.
High-quality exposure-related data is a missing link in occupational health surveillance but is a critical component of research. This data is particularly valuable for agents that have chronic health effects and for emerging issues, and it can be used to focus research and establish priorities to gain maximum impact on illness rates. Currently, U.S. quantitative exposure data are available from only one source: OSHA’s Integrated Management Information System. The data were collected beginning in 1979 to document results of inspections and consultations but have many shortcomings in terms of secondary uses of the data. The kind of data that would be valuable for a national database exist, but, unfortunately, it is kept in individual files and local databases and is not available for secondary uses. Earlier efforts of AIHA and ACGIH, to promote the development of a national occupational exposure database that would have identified the key exposure-related data, stalled. However, through the AIHA-NIOSH alliance, representatives from various groups are working together to identify the barriers to development of a national occupational exposure database and explore solutions. The barriers to organizations in sharing information will be discussed as well as the incentives for organizations to share. The barriers and issues have been categorized into three broad groupings: organizational/legal, data, and technological. The process of development of recruiting materials specific to the potential concerns of five groups — academia, business, consulting, insurance, and government — will be discussed. The selection process for agents in the pilot will also be discussed.
J. Koehn, Jan Koehn, CIH Inc., Houston, TX; C. Lewis, Creative Safety Solutions, Santa Fe, TX.
During 2006, a variety of site monitoring projects was undertaken to determine the actual potential for workplace exposures to hexavalent chromium in accordance with the recently published OSHA regulation. Based on requirements of Title 29, Code of Federal Regulations, part 1910.1026, the goal of each monitoring effort was to assist with generating representative personal monitoring data for job positions with a potential for elevated occupational exposures. An industrial hygiene (IH) exposure assessment procedure was conducted for routine job work activities for numerous industrial and manufacturing clients. The procedure addressed specific job positions with a potential for occupational exposure related to identified workplace operations. Full-work-shift breathing zone monitoring using NIOSH Method 7605 was completed during March through December 2006 for various work operations including welding and plating. Extensive site documentation was specifically noted regarding job positions, work tasks, descriptions of the work environments along with site observations, applicable control measures including ventilation, sampling conditions, and personal protective equipment. Personal occupational full-shift exposures were recorded below the new permissible exposure limit for hexavalent chromium, but some results exceeded the action level for the separate monitoring projects. Trained and experienced IH personnel performed the monitoring work, recorded specific site observations, and documented job work tasks along with existing conditions. The project sampling strategy was implemented at each field site, and all personal samples were analyzed by an AIHA-accredited laboratory. Final project reports were prepared summarizing the monitoring data and the pertinent workplace exposure assessment information to provide necessary documentation and project recommendations for each client. Available control measures were further investigated as they relate to necessary follow-up monitoring, in accordance with specified regulatory requirements to assist with assessment related to required standard compliance and reduction of occupational exposures.
J. Koehn, Jan Koehn, CIH Inc., Houston, TX.
During 2006-2007, a workplace exposure assessment project was specifically undertaken for hydrogen sulfide (H2S), which was associated with routine transport and storage of molten sulphur involving standard work activities at a Gulf Coast terminal facility. Based on the existing increased potential for elevated and harmful exposures, the project goal was to collect a combination of representative air monitoring data for H2S. An in-depth workplace exposure assessment consulting project was outlined on a quarterly basis, starting in September 2006 and addressing both operations and maintenance work. Monitoring of personal breathing zone and also area monitoring for H2S through use of calibrated dataloggers was conducted for each type of transport and unloading or loading operations. Further sampling methods were employed including colorimetric and/or sorbent tubes during identified work tasks with a substantially increased potential for occupational exposures. Calibrated direct-reading instruments were also used for site data collection to best describe peak occupational exposure during grab sampling monitoring. The following operations were addressed involving molten sulphur: unit train venting and unloading; barge unloading and loading; unloading of tank trucks at sumps; and loading for ship transport. Operations and also full-shift maintenance work activities were identified for personal monitoring as well as specified area locations. Short-term work tasks, including tank gauging and grab samples at truck and train sump locations, were further outlined for documentation. Supplied air respiratory equipment was used, based on standard company procedures and operator work activities. A certified industrial hygienist performed site monitoring and prepared quarterly summary reports including data interpretation. The sampling strategy was implemented and revised as needed, based on site-work activities including variable wind directions. Documentation was recorded regarding job position, work tasks and procedures, sampling criteria, control measures used, ventilation parameters, weather and climatologic conditions, and personal protective equipment.
T. Morris, Ohio BWC, Cincinnati, OH.
Among the parameters considered for an exposure assessment are the quantity of a toxicant and its vapor pressure (VP). VP is not normally considered for metals, but for high-temperature processes it can be a key to identifying an exposure source. There can be a wide range of boiling points among a metal’s alloying elements, and low boilers can be released, resulting in exposure and quality issues. Assessments are typically concerned with the so-called “primary” contaminants, and even if known, trace substances are ignored because it is assumed there is not enough present to pose a hazard. Trace substances range from an added component to an impurity and are rarely listed on an material safety data sheet. Even at trace levels there can be substantial toxicant present, especially when large quantities of the parent material are processed.
Special high-grade (SHG) zinc is used for alloying at brass/bronze foundries. At the ASTM standard’s 0.003% maximum, 454 g (1 lb) of SHG zinc contains 13,620 µg of cadmium. Zinc used at the study foundries contained as little as 0.0002% cadmium (Cd) (908 µg). Zinc (1 or 2 lbs) is added to the metal (~1200°C) prior to pouring, generating a white plume (the Cd boiling point is 765°C). The maximum Cd concentration measured within a plume was 3070 µg/m3. Cadmium exposures were related to proximity to the plume, with pourers at 8.1 µg/m3, furnace operators 1.6 µg/m3, and finishing workers 0.4 µg/m3 (action level and permissible exposure limit are 2.5 and 5 µg/m3, respectively). This study demonstrates that under proper conditions, even a trace substance can be released in sufficient quantity to pose a health hazard. Cadmium exposure should be considered when zinc or zinc-containing materials are used, especially in high-temperature processes. It is imperative that a material’s trace composition and physicochemical characteristics be considered when evaluating exposure potential.
K. Karns, M. Smith, Los Alamos National Laboratory, Los Alamos, NM.
Workers within the Weapons Physics Directorate at Los Alamos National Laboratory are involved in experimental efforts that require them to work near or within areas potentially contaminated with beryllium. Personnel involved in maintenance work also have the potential to be exposed to beryllium particulates. Characterization of these areas can be difficult because they involve trees, grasses, bushes, and soil located around the experimental firing point. Also, contamination levels change after each experiment. There are times when a fire occurs in the beryllium contaminated woodland area and firefighters must enter the area. This raises the following questions: How much beryllium is released during a fire? What is the potential exposure to workers when the grasses are mowed and the trees, weeds, and shrubs are removed from the area? To answer these questions, bulk samples were collected and chemically analyzed, then compared against the baseline of forest materials. Personal air samples were collected while the firefighters and maintenance workers were in the area. Swipe samples were collected from workers’ personal protective boots. Beryllium is a naturally occurring metal in our soils. The sample results show higher levels of contamination than normally occur in the Los Alamos County area. For example, the regional statistical reference level in soil is 0.8-1.2 ppm. Although the personal air samples did not detect beryllium, based on elevated environmental levels, there is the potential for beryllium exposure, so all workers and firefighters must wear personal protective equipment and possibly respiratory protection in the contamination area. This presentation will provide (1) key elements of the evaluation, (2) details of the sampling methods and results, and (3) selection of the controls for worker protection.
WITHDRAWN
G. Popov, D. Bryant, University of Central Missouri, Warrensburg, MO.
Methamphetamine is an illegal and highly addictive central nervous system stimulant that can be injected, inhaled, smoked, or ingested orally. Methamphetamine can easily be made using store-available materials and is the most prevalent synthetic drug manufactured in the United States.
The effects of methamphetamine use can include addiction and chronic physical and mental health problems, including psychotic behavior, stroke, epilepsy, and brain damage. In addition, the effects of methamphetamine pose a serious and growing risk to the health, safety, and welfare of citizens and the environment. Methamphetamine production is associated with the release of various chemicals, such as volatile organic compounds (VOCs), metals, chemical salts, acids, and bases, in addition to methamphetamine. Specific residues may vary depending on the cooking process used. Airborne contaminants are absorbed or deposited onto surfaces such as carpets, furniture, drapes, kitchen appliances, and walls. The residues may also enter and contaminate heating, ventilation, and air conditioning systems. This poster attempts to reconcile what is known about methamphetamine fine and ultrafine particles deposition, sampling methods, and different analytical procedures. Three different analytical methods are evaluated and compared to the levels currently being used as cleanup standards. Laboratory analytical methods are constantly being refined and detection limits lowered. Three different field tests were developed last year and presented at AIHce in 2006. However, real-world comparison of the detection levels was not provided. The author used two field tests and compared the results with the laboratory analysis of the samples collected from the same surfaces. The information summarized in this poster will provide industrial hygienists with a balanced approach for weighing the field sampling/analysis limits against practicability and cost considerations. Two case studies are selected to describe the methamphetamine particles deposition and determination of the contamination levels.
J. Jang, Korea Occupational Safety and Health Agency, Incheon, Republic of Korea.
Inspectors of the Ministry of Labor of Korea and consultants of the Korea Occupational Safety and Health Agency (KOSHA) use the statistical techniques suggested in the OSHA Technical Manual (OTM) for judging their occupational exposure monitoring results. The calculation methods for a full-period, continuous single sample and for full-period consecutive samples holds little issues in dropping a monitoring result into any one of three exposure management categories: violation, no violation, and possible violation. In cases of mixture monitoring, OTM does not clearly define “possible violation” and “no violation.” When inspectors or consultants do partial period sampling for less than an 8-hr work shift, judgments of the results are more complex. A mixture upper confidence limit (MUCL) and mixture lower confidence limit (MLCL) are suggested for dropping any monitoring result for mixtures into any one of the three management categories. MUCL can be defined as 1+ pooled sampling and analytical errors (RSt), and MLCL can be defined as 1- RSt. These concepts are similar to the upper confidence limit (UCL) and lower confidence limit (LCL) for single chemical samples in OTM. Sampling and analytical error (SAE) for each chemical can be found in the OSHA-91B report form. For partial period samplings, that is not arranged in OTM, a partial period upper confidence limit (PUCL) and partial period lower confidence limit (PLCL) are suggested for managing any working environment in which samples are monitored. Any partial period sample is less certain to fall into one of the three management categories, because there should be a consideration of an unsampled period for the work shift. For full-period samples, a uncertain range for “possible violation” is defined as 1±SAE (sampling and analytical error) in OTM.
E. McCormack, CHPPM-North, U.S. Army, Fort Meade, MD.
This study examines the diesel exhaust emission rates of the multiple launch rocket system (MLRS) and determines the potential for overexposures in MLRS storage facilities. The MLRS is an automatic artillery system that contains a fire control computer that integrates the vehicle and rocket launching operations. The integrity of the vehicle’s launcher module requires that the launcher be idled regularly. The diesel exhaust emitted from the MLRSs, when stored in buildings not outfitted with local vehicle exhausts, presents a potential hazard to employees who maintain the vehicles. This study was conducted in the upper midwest United States, where the annual ambient temperature is predominantly cold. The weather played a large part in this study, because of the storage constraints and variance it created in the sampling. Requirements for storage garages are based on the short-term exposure limit (STEL) of drivers to exhaust emissions when entering or departing the building. While the MLRSs were idling, general area air sampling was conducted to measure the STEL concentrations of carbon monoxide (CO), nitric oxide (NO), sulfur dioxide (SO2), and nitrogen dioxide (NO2). Collected while 9 of 18 possible MLRSs were idling inside a storage building, data approached but did not exceed the ceiling limit for NO2. Maintenance personnel noted that cold ambient temperature produces increased stress on the vehicle’s fuel pistons, causing an excess of diesel fuel to leak around the pistons and the MLRS to consequentially produce more diesel exhaust. Sampling was conducted when the outside temperature was 70-75şF. The diesel exhaust emission data collected was projected to consider the increase of stored MLRSs and ambient storage temperatures below 45şF. Data projection revealed that drivers would be overexposed to NO2 if all 18 MLRSs were idled simultaneously during cold ambient temperatures.
L. Riklik, D. Chung, Ontario Workplace Safety and Insurance Board, Toronto, ON, Canada.
When a claim is made to the Ontario Workplace Safety and Insurance Board that a disease is work related, after the medical information has been collected the next stage is an assessment of the potential workplace exposures. This assessment can then be compared to policy, guidelines, or the merits and justice of the individual case with regard to the possible work-relatedness of the specific disease. These assessments encounter many challenges, including lack of access to the worker, major changes in the work environment, lack of historical process information and credible sampling data, and complex work histories. In this model, the retrospective exposure assessment is broken into three elements. The first element is a workplace employment history, which includes dates, employers, job titles, tasks, and a brief list of occupational exposures. The next element, workplace exposure assessment, takes relevant agents of interest and provides an assessment of the intensity or likelihood of exposure, frequency of exposure, and duration of exposure for each specified period of time. Narrowing the relevant agents of interest to move from employment history to exposure assessment can be a complex task, requiring a decision logic that itself needs many sources of data. The final element is the exposure assessment report, which potentially can have both quantitative and qualitative descriptions. The exposure assessment report can then be compared by a physician or adjudicator to policies, guidelines, toxicological and epidemiological studies, and occupational hygiene exposure guidelines. This poster describes the sources of data for the various elements of the retrospective exposure assessment process, including primary sources such as interviews, documentation, walk-through observations, and modeling; secondary published sources; and extrapolation of data using professional knowledge and judgment.
R. Newton, Liberty Mutual Insurance Co., Marietta, GA.
A systematic and comprehensive approach to exposure assessment is the best way for organizations to understand and manage the ever-broadening realm of occupational health-related risks. A thorough understanding of exposures allows the industrial hygiene (IH) program, including control efforts, to be prioritized to protect employees and manage exposure-related risks. It also puts the IH in a better position to manage the unpredictable changes that will occur both in the knowledge of the health effects of agents and in society’s tolerance of workplace exposures. This qualitative risk assessment database accomplishes the following: (1) uses established job safety analysis methods to rank activities for similar exposure groups; (2) assigns a perception of risk for a given activity, associated with chemical, physical, or biological agents; (3) calculates a risk rating, using either quantitative or qualitative data; (4) provides a clear prioritized listing of exposures, ranked by the level of perceived risk; (5) targets resources at the most severe occupational disease (OD) risk; (6) allows management to establish acceptable risk levels for that particular organization; (7) provides a record of progress made toward risk improvement (lowering of the risk rating); (8) documents the logic used to assess risk; (9) documents existing control measures for each OD risk; and (10) uses a database to track and compare changing risk at different locations over time.
D. Turner, T. Hethmon, Rinker Materials Corp., West Palm Beach, FL.
Gravimetric methods of dust measurement have been well characterized but are limited in their ability to differentiate temporal and spatial variation in concentrations. This study had two objectives: (1) examine specific dust sources using aerosol photometers to rank-order respirable dust levels in preparation for controls, and (2) evaluate existing dust controls to determine if they were adequate. Studies were conducted in 2005 and 2006 at six U.S. quarries, each using different mining methods and having different geological deposits, including limestone, sand and gravel, and granite. In addition, manufacturing sites with ready-mixed concrete and asphalt operations were also evaluated. Two commercial laser photometers with respirable ranges of 0.001 mg/m3 to 100 mg/m3 and 0.001 to 400 mg/m3 respectively, and resolution of ± 0.001 mg/m3 were used in this cross-sectional study. Monitoring sites included crushers, conveyor transfer points, haul roads, and the inside and outside of operator enclosures. The data revealed ranges of peak-to-average dust concentration ratios of 1.4 to 190, but the majority of this temporal variation was short-lived (minutes). Also, dust concentration variations were noted when weather or truck traffic produced modest increases in wind velocity(about 10 mph).