Poster Session 405

Graduate Students

1
Carpal Tunnel Syndrome: Causes and Controls

S. Ahuja, R. Thomas, Auburn University, Auburn, AL

Carpal Tunnel Syndrome (CTS), classified under Musculoskeletal Disorder (MSD), is the most common nerve entrapment syndrome to affect people performing with their hands, such as industrial workers, surgeons, dentists etc. Carpal Tunnel Syndrome affects an estimated 3 percent of adult Americans. NIOSH predicts that, every year, approximately two out of every 1,000 workers will experience CTS, leading to significant medical expenditures, lost work wages or workers compensation. But, the literature does not provide a single source which summarizes the physiology, associated occupational factors, symptoms, diagnosis, available treatments and precautions to be taken to cure CTS. A literature review involving peer-reviewed journal articles and federal epidemiological data was conducted to address the above mentioned issues. 

This poster will synopsize the literature review provide a basic understanding of CTS to novice readers. The poster will emphasize risk factors (external forces, metabolic factors, systemic diseases etc), target populations, occupational and non occupational factors associated with Carpal Tunnel Syndrome. The poster will also provide statistical information on the CTS cases involving days away from work for 1992-2002. The distribution of CTS cases among non-fatal occupational injuries and illnesses involving days away from work for 1994-2002 will also be presented.

2
Occupational Exposure to Snowmobile Emissions at Yellowstone National Park

W. Campbell, D. Stephenson, Boise State University, Boise, ID, R. Morris, T. Spear,  Montana Tech of University of Montana, Butte, MT.

In recent years, regulations regarding snowmobile recreation in Yellowstone National Park have become more restrictive.  New regulations limit the number of snowmobiles entering the park, restrict the engine type, and require that all riders utilize a licensed guide.  Given these regulations, it is hypothesized that occupational exposures to the combustion products from snowmobile emissions have decreased.  The purpose of this research is to determine if compliance with current regulations regarding snowmobile recreation in Yellowstone National Park has any affect on the occupational exposures received by park employees during the performance of their normal job tasks.  This study performed occupational exposure monitoring of National Park Service employees working at the West Entrance to Yellowstone National Park during the 2005 winter recreation season.  Personal and area samples to characterize employee exposures to snowmobile emissions were taken at the West Entrance to Yellowstone National Park.  The chemical and physical agents sampled included carbon monoxide, nitrogen dioxide, volatile organic compounds, respirable particulates, and noise.  Sampling results for all agents showed that park service employees did not receive occupational exposures above the current TLV or PEL.  In an effort to evaluate changes in long-term exposures, the analytical results for all samples were compared to similar occupational exposure results measured during previous studies.  This comparison showed no statistically significant decrease in occupational exposures for all agents (t-test; p = 0.09).  However, there were decreases across a majority of exposures, suggesting that application of recent administrative controls regarding snowmobile recreation in Yellowstone National Park are working to further protect employees from adverse exposures.

3
Knowledge, Skills, and Abilities Essential to the Practice of Industrial Hygiene

E. Rodgers, J. Zey, D. Bryant, J. Laster, Central Missouri State University, Warrensburg, MO.

The discipline of Industrial Hygiene is in transition.  Numerous authors have speculated on the future of this discipline.  Inquiry into the job skills, knowledge areas, and expected competencies of professionals in this area of practice is a continuous process.  Academic programs, accrediting organizations, and certification boards are examining which knowledge, skills, and abilities (KSAs) are necessary and essential to the practice of Industrial Hygiene.  This study was undertaken to assess the perceptions of Industrial Hygiene professionals.  The 160 national members of the American Industrial Hygiene Association (AIHA) residing in Missouri were chosen to participate in the study. The Central Missouri State University (CMSU) Human Subjects Review Board approved the study design and questionnaire.  Each AIHA member was mailed a packet including instructions for participation and a questionnaire listing 44 topic areas.  Each participant was asked to identify each knowledge, skill, and ability either as essential, useful but not necessary, or not necessary.  Additional information requested included level of education, professional certifications, years of experience, and primary area of practice.  Out of 160 questionnaires, 110 were completed and returned, resulting in a response rate of 69% (110/160).  The majority of the respondents (59%) possessed the Certified Industrial Hygienist (CIH) or Certified Safety Professional (CSP) certification.  Additionally 84% of the respondents indicated that their primary area of practice was Industrial Hygiene or Safety.  Only 9 of the 26 technical topics were identified as essential by more than 70% of the respondents.   At least 20% of the respondents thought four of the technical topics were not necessary.  Five other technical topics were identified as useful but not necessary by more than 50% of those surveyed.  There was more agreement on the value of communications skills, with at least 70% of the respondents identifying 15 of the 18 communication skills and abilities as essential.

4
Inter-Rater Reliability of Postural Variables Using Multimedia Video Task Analysis

A. Dartt, J. Rosecrance, P. Chen, Colorado State University, Fort Collins, CO

The purpose of this pilot project was to evaluate the inter-rater reliability of posture during work tasks using Multimedia Video Task Analysis (MVTA).  MVTA was used to assess posture of the neck, shoulder, and wrists of manufacturing workers. The posture variables were defined as the duration of task time spent in specific anatomical positions for the neck, shoulder and wrists. The three anatomical positions were analyzed for each of seven tasks by two raters. Each rater was blinded to the results of the other rater. Pearson product-moment correlation coefficients were computed to assess inter-rater reliability for each task. Correlation coefficients ranged from 0.73 to 0.98 for the seven tasks indicating moderate to very high reliability. The overall correlation coefficient (across all tasks and anatomical positions) was 0.87.  This pilot study provided data to perform an initial assessment of inter-rater reliability using MVTA. The results also provided data to help determine the number of subjects needed in future assessments of inter- and intra-rater reliability of each anatomical position. While the neck, shoulder, and wrists of workers were analyzed, only the overall inter-rater reliability for each task was determined.  It is likely that the inter-rater reliability varies with the three anatomical positions analyzed.  Further study is needed to assess the inter-rater reliability for each anatomical position, determine intra-rater reliability, and to determine the validity of this exposure assessment tool.

5
Integration of Participatory Ergonomics and Lean Manufacturing: A Model and Case Study

D. Douphrate, J. Rosecrance, Colorado State University, Fort Collins, CO

The purpose of this demonstration project was to integrate a participatory ergonomics process with the lean manufacturing process at a surgical equipment manufacturing facility.  Over a two-year period, management developed and refined a lean manufacturing process to systematically identify and eliminate non-value added activities through continuous improvement.  Global competition required the facility to improve product quality, reduce delivery time, and lower production costs. With the elimination of non-value added activities and subsequent changes in job demands, management was concerned about the effects the changes could have on employee health. To prevent the development of musculoskeletal disorders among employees, management integrated a participatory ergonomics process with their lean manufacturing process. The participatory ergonomics initiative was a cyclical five-step process of problem identification and analysis or ergonomic risk factors, followed by the development, implementation and evaluation of ergonomic solutions.  Many of the employee-based ergonomic initiatives not only decreased exposure to the physical risk factors associated with musculoskeletal disorders, but also led to improvements in product quality, less product handling, and elimination of non-value added activities.  All ergonomic changes were cost justified and with an average return on investment in two years or less. One example of an employee-based ergonomic initiative was the modification of the painting process to decrease the risk factors of repeated trunk bending and twisting as well as static work postures.  The integration of ergonomic and lean manufacturing processes was used to reach common goals and the processes were determined to be complimentary.

6
Preliminary Evaluation of Worker and Environmental Exposures From Dairies and Cattle Feedlots

B. Lester, S. Reynolds, T. Stanton, Colorado State University, Fort Collins, CO.

In 2001, Colorado ranked 18^th in the nation with approximately 80,000 dairy cows on 500 farms which produced approximately 1.97 billion pounds of milk annually.  Workers on dairies and feedlots are exposed to excessive levels of hydrogen sulfide, ammonia, other gases, and aerosols including bacterial endotoxins.  The goals of this study were to characterize occupational exposures for various tasks including milking, feeding, maintenance, working sick cows, and driving tractors; and to characterize environmental exposures to gases and odors downwind of the lagoon.  Environmental and meteorological results were as follows: temperatures ranged from -9.9 to 24.3 °C with a mean of 9.8 °C.  Relative humidity ranged from 0.6 to 85.3% with a mean of 27.4%.  Hydrogen sulfide ranged from 0 – 670 ppb with a mean of 32.5 ppb.  Ammonia ranged from 0 – 3 ppm.  Carbon dioxide ranged from 400 – 616 ppm with a mean of 481 ppm.  Scentometer readings ranged from 0 – 15 dilutions to threshold (D/T) with a mean of 7 D/T.  The mean concentration of culturable mesophilic bacteria downwind of the lagoon was 1.8x10¹⁰ CFU/m³.  Total particulate and endotoxin levels were 0.57 mg/m³ and 41.4 EU/m³ at the lagoon, respectively.  Inhalable particulate and endotoxin levels were 0.177 mg/m³ and 9.2 EU/m³ at the lagoon, respectively.  Occupational exposure results were as follows:  the mean concentration of culturable mesophilic bacteria in a barn was 1.1x10¹⁰ CFU/m³.   Total particulate and endotoxin levels were 0.46 and 1.41 mg/m³, and 352.0 and 577.6 EU/m³ for maintenance and milkers, respectively.    Inhalable particulate and endotoxin levels were 1.83, 0.72, 0.59, and 1.2 mg/m³, and 494.4, 360.1, 206.6, and 728.1 EU/m³ for working calves, working sick cows, feed mixing tractor, and feed loading tractor, respectively.  Levels of hydrogen sulfide, endotoxin, and mesophilic bacteria exceed recommended occupational and environmental levels and could create significant health concerns.

7
Comparison of Personal Nephelometers and Handheld Dust/Aerosol Monitors to Gravimetric Samplers Developed for Occupational Exposure Assessment.

J. Nakatsu, S. Reynolds, M. Tillery, T. Keefe, R. Thate, Colorado State University, Ft. Collins, CO; P. O’Shaughnessy, University of Iowa, Iowa City, IA.

Direct reading aerosol photometers are currently used in occupational and environmental exposure assessments to provide real time concentration measurements.  The aim of this study was to evaluate and compare measurements made by two direct-reading MIE personal DataRams (pDR) and PPM handheld aerosol monitors (HAM) to five pairs of gravimetric samplers under predetermined wind-tunnel conditions. In addition to determining differences in sampler performance, we sought to develop correction factors for the direct reading devices.

Pearson’s correlation coefficients (r), for Coarse Arizona Road Dust aerosolized at a 0.2m/s velocity resulted in both HAM and pDR r values between 0.996 and 0.954 with respective p-values of 0.004 and 0.034.  Likewise comparisons at 1.0m/s resulted in pDR, coefficients ranging from 0.994 to 0.953 with p-values between 0.006 and 0.047. Tukey’s multiple comparison tests at both wind speeds showed significant differences between both the HAM and pDR devices compared to the IOM sampler and the inhalable fraction of the IOM sampler with MultiFoam disc. Actual inhalable concentrations of Coarse dust at both wind speeds varied from 9.124 to 53.156 mg/m³.  Identical analysis of Fine Arizona Test Dust aerosolized at 1.0 m/s resulted in r values as high as 0.967 with corresponding p-values between 0.067 and 0.928. At the 0.2 m/s velocity, significant r and p-values were only seen between the four direct reading instruments. Tukey’s analysis found a significant difference between each direct reading device to the respirable portion of the IOM with Multifoam disc at 0.2 m/s as well as differences between the pDR’s, total dust, IOM, and HAM’s at the 1.0 m/s velocity.  Resulting respirable concentrations for the Fine test dust ranged from 4.28 to 21.25 mg/m³ with inhalable concentrations between 11.95 and 37.26 mg/m³.  These findings suggest that wind speed along with particle size may have an effect on aerosol photometer performance.

8
Health And Safety at Workplaces in Italian Stone Shops: A Systematic Analysis in an Important Production Area.

S. Nobile, M. Patrucco, Polytechnic of Turin, DITAG, Torino, Italy; F. Lembo, SPreSAL, Verbania, Italy

The paper deals with the results of a research work carried out by the Department of Land, Environment and Geotechnology in cooperation with the VCO ASL 14 S.PRE.Sal (a branch of the National Safety Bureau) in order to get structured information about workers’ health and safety conditions in the stone sector. The VCO, sited in the Northern Western Italy, counts a wide range of dimensional stone quarries and shops and represents one of the most important Italian mining districts in terms of occupational level, high productivity and high quality products. The research approach is based on: a) a systematic data collection on both the health impairments and injuries occurrences drawn from national and local statistic databases; b) a detailed analysis of the most critical cases, based on reports recorded by the safety inspectorate technicians; c) a direct screening of safety characteristics of machineries, fittings and operating procedures, with reference to statements of the Italian enforcement of the 89/391/EEC and 89/392/EEC Council Directives. The results of the research work are organized in terms of heath impairment and injury occurrence and their incidence rates in number and lost workdays: hearing loss and silicosis can be considered the most concerning working diseases (~ 80%); on the other hand, working accidents appear to be mainly related with fall or slip of materials in stock or during handling operations (~ 65%), fall from height during maintenance operations (~ 15%), collision with moving machines (~ 10%). A detailed guideline for risk analysis focused on the stone sector is actually in progress.

9
Noise Exposures to Line Crew Personnel During Operations at Two Coast Guard Air Stations

S. Unthank, R. Herrick, Harvard University, Arlington, MA

Air Station operations are essential to the mission of the US Coast Guard.  However, along with the integral role they play, aircraft operations also contribute a large source of noise exposure to those working in and around the aircraft.  This assessment focused on the line crew at two Coast Guard Air Stations, and evaluated the noise exposures to personnel working in and around the aircraft hangers, as well as the exposures to personnel working on the flight lines during the start-up and taxiing of the aircraft.  The daily activities of the line crew are essential to the operations of the Air Station and require close proximity to aircraft during the engine start-up cycles and taxiing.  This exposure, coupled with their work in and around the aircraft hanger, makes the line crew members especially susceptible to very high noise exposures.

Two Coast Guard Air Station line crew teams were sampled.  The aircraft handled at these facilities included the HC-130 Hercules Aircraft, the HU-25 Falcon Jet, and the HH-60 Jayhawk Helicopter.  The sampling period was typical of normal operation for each Air Station.  Eight hour TWA ranged from 78 dBA to 98 dBA for the members of the line crew.  However, short term peak levels were at the upper limit of detection, 140 dBA, for almost all of the members.  Additionally, doses in excess of 2000% were found for personnel working in the closest proximity to the aircraft during start-up and taxiing.

Additional research is needed to determine the frequency distribution of the noise exposures to ensure that the hearing protection used is adequate in the frequency ranges with the highest exposures.  By instituting better administrative controls to reduce the non-flight line exposures, and by ensuring the best available personal protective equipment is provided during flight line operations, these exposures can be reduced and the crew can be better protected. 

10
Noise Exposure Levels in Three Outdoor Skateparks With Different Ramp Materials

R.L. England, F. Akbar-Khanzadeh, Medical College of Ohio, Toledo, OH.

Skatepark activities expose individuals to certain harmful factors such as mechanical agents, solar radiation, thermal stress and, most importantly, to loud noise. This study was performed to evaluate the extent of noise exposure in three outdoor skateparks with wooden, metallic and concrete ramps using real-time sound level meters. Noise sources included the activities of between 10 and 20 individuals using skateboards and rollerblades on the ramps. The peak noise level in the wooden-ramp skatepark ranged from 99-144 dB with mean (SD) of 126 (14) dB, in the metallic-ramp skatepark ranged from 101-147 dB with mean (SD) of 119 (11) dB and in the concrete-ramp skatepark ranged from 109-145 dB with mean (SD) of 130 (10) dB. The Leq dBA noise level in the wooden-ramp skatepark ranged from 85-92 with mean (SD) of 88 (2), in the metallic-ramp skatepark ranged from 72 -104 with mean (SD) of 83 (6) and in the concrete-ramp skatepark ranged from 79-93 dB with mean (SD) of 87 (4). The results of this study indicate that noise exposure levels in these facilities exceed recommended limits, and in order to protect participants and bystanders, those levels should be controlled using engineering controls or through the use of personal protective equipment.

11
Comparison of Chemical Hood Test Results Using Both ASHRA 110-1995 and ANSI/AIHA Z9.5-1992 Methods: A 4-Year Study (2001-2004) at Case Western Reserve University

M. Fahim, S. Milz, M. Bisesi, C. Keil, Medical College of Ohio, Toledo, OH; M. Rubin, Case Western Reserve University, Cleveland, OH.

Chemical laboratory hoods are one of the most important engineering control devices in research laboratories to reduce chemical exposure. Several institutions are currently using the ANSI/AIHA Z9.5-1992 (American National Standard Institution/American Industrial Hygiene association) standard in which an average face velocity of 80-120 feet per minute (fpm) with no single velocity measurement more than plus or minus 20% of average is recommended. The ANSI/AIHA-2003 standard for laboratory ventilation no longer validates the face velocity as the only factor determining the hood performance. This standard requires a hood containment test such as ASHRAE 110-1995 (American Society of Heating, Refrigerating, and Air Conditioning Engineers) method to be performed. In the current study, a total of 484 tests were performed on hoods with different dimensions and types using both ANSI/AIHA-1992 and ASHRAE-1995 methods. Out of these 484 tests, 108 tests (22.3%) were performed on low flow hoods, 201 tests (41.5%) were done on variable air volume (VAV) hoods, and 175 tests (36.2%) were performed on standard hoods. Standard hoods had the highest passing rate for ASHRAE 110-1995 test (82.9%), followed by VAV hoods (82.1%), and low flow hoods (67.6%). Statistical analysis revealed that there was a statistically significant difference between the results of the two methods in VAV hoods (p= 0.038). No significant differences were observed in other types of hoods. Results of tracer-gas tests demonstrated that 19% of the fume hoods (standard and VAV) tested in the 80-120 fpm range failed to show proper containment. In the 80-120 fpm range, 11% and 24% failed to show proper containment in the standard hoods and VAV hoods, respectively. If performed alone, 19 percent of the face velocity test results would have been falsely positive. Therefore, using a containment test method such as ASHRAE 110-1995 is necessary for hood performance evaluation.

12
Total Noise Exposure Assessment of a Farm Family

M. Witherspoon, S. Milz, Medical College of Ohio, Toledo, OH.

An ongoing pilot project is being conducted in Northwest Ohio to assess both the occupational and non-occupational noise exposures of farm families. The study was designed to monitor 3-5 family members from three families living and working on the farm for one week each during planting, growing, and harvesting season. Each participating family member wore a dosimeter during all waking hours. Each dosimeter had been programmed to record 24 hours a day using both the OSHA and the NIOSH parameters. Additionally, the participating family members completed daily time activity logs to record all on-farm and off-farm activities. Members of the research team were also on site each monitoring day for dosimeter calibration, battery change out, sound level measurement collection, and time activity recording.

The first farm family enrolled in October 2004. Three family members agreed to participate. One worked on the farm full-time, one worked off the farm full-time and helped on the farm, and the third attended school full-time and helped on the farm. Three weeks of monitoring were completed in 2004 including harvesting, planting of winter wheat, and growing season for winter wheat. A preliminary analysis of data excluding all non-farm activities was conducted.  Occupational exposures for the full-time farmer were 55.3 – 88.9 dBA 8HR TWA using the OSHA parameters and 67.3 – 91.6 dBA 8HR TWA using the NIOSH parameters. The exposures during farm activities for the other two family members were 67.1 – 81.2 dBA 8HR TWA using the OSHA parameters and 77.6 – 85.5 dBA 8HR TWA using the NIOSH parameters. Maximum occupational exposures exceeded the NIOSH guidelines, but not the OSHA standards for the full-time farmer. Farm work exposures for the other two family members were below the OSHA standards, but exceeded the NIOSH guidelines on one day. Future analysis will link exposures to activities.

13
Exposure and Control of Emissions of Diesel Particulate Matter From School Bus Engines

T. Bonner, N. Zimmerman, Purdue University, West Lafayette, IN.

Diesel engine exhaust components are believed to have acute and chronic adverse health effects on exposed populations causing neurophysiological problems, respiratory illness, and potentially cancer.  More stringent EPA regulations, planned for 2007, will require a reduction in the emission of environmental pollutants from diesel engines.  With aging bus fleets still on the road, there is a need to retrofit older buses to reduce the emission of hazardous pollutants.  Using particulate matter concentrations as indicators of emission reduction, an evaluation of the effect of control devices on exposure potential was performed.

Two sources of diesel particulate matter emissions were identified during preliminary testing: 1) an ultrafine fraction (<0.1µm diameter) originating from the tailpipe as a combustion process byproduct, and 2) a fine fraction (~ 2.5µm diameter) emanating from the engine crankcase.  An ultrafine particle counter (TSI P-Trak), and an aerosol monitor (TSI Dust-Trak) were placed inside a school bus, and data were recorded during runs of a representative bus route.  Two retrofit control devices for each source of particulate emission were attached to the bus during a series of runs, and the results were compared to a conventional bus configuration.  The devices evaluated for the control of tailpipe emissions were the Diesel Particulate Filter (DPF) and the Diesel Oxidation Catalyst (DOC).  The Donaldson Spiracle and the Fleetguard Enviroguard were evaluated as the crankcase emission filtering devices.  For ultrafine particulate the DPF reduced emissions by 69% while the DOC reduced emissions by 17% (15,550pt/cc and 41,890pt/cc average concentration respectively compared to 50,530pt/cc for conventional). For fine particulate the Spiracle reduced emissions by 61% while the Enviroguard reduced emissions by 38% (0.036mg/m³ and 0.057mg/m³ average concentration respectively compared to 0.092mg/m³for conventional). The combination of the DPF and the Donaldson Spiracle proved to be the most effective configuration to reduce exposure to passengers.

14
A Wireless Real-time Video Exposure Monitoring System as a Basis for Health Risk Assessments of Airport Ground Crew From Aviation Emissions

A. Goh, J. McGlothlin, F. Xu, Purdue University, West Lafayette, IN.

The wireless Video Exposure Monitoring (VEM) technology pioneered in Purdue’s Research Exposure Assessment Research Laboratory (PEARL). This system captures real-time noise and particulate data and provides instantaneous results in the form of data-streaming along with video recordings of environmental and airport activities. Customized software transmits and digitally synchronizes the information to a computer for detailed experimental analysis. Initial field testing of PEARL’s wireless VEM system was conducted at Purdue’s airport perimeter on a single engine aircraft and a WWII B17 Bomber. Experimental data analysis points to a correlation between an increase in particulate concentration and plane activity. It also indicates consistently peaking noise levels corresponding to multiple plane activity. From the preliminary observations of the correlations between the noise levels and particulate concentrations, we may be able to use the obvious interaction between noise level and plane activity to hypothesize a relationship between particulate concentration and plane activity. Refinement of the system to collect additional data about other environmental conditions such as wind speed and direction will aid in drawing stronger conclusions about the hypothesis. PEARL’s patented wireless VEM technology provides opportunities to concurrently monitor changes in health parameters (i.e. heart rate, blood pressure, respiratory rate) with detailed data/video profiles of particulate emissions and noise levels. This simultaneous exposure monitoring of humans and airplanes with supporting infrastructure will provide insight into the relationships between airborne particulates and noise from airport combustion emissions and associated health effects.

15
Ergonomics in Construction: Evaluation of a Footer Preparation Process in the Post-Frame Building Industry

M. Knezovich, J. McGlothlin, Purdue University, West Lafayette, IN.

The current, or pre-intervention, footer preparation process of a post-frame building construction crew was examined as part of an ergonomics intervention study involving several engineering controls.  Data from the pre-intervention process was examined both to develop specific ergonomic controls for the post-intervention part of the study and for comparison to post-intervention data in order to determine the effect on physical work demand.  Measured tasks of interest in the pre-intervention phase of the study included the use of a standard post-hole tool for removing excess soil from pre-drilled holes, the manually lifting and dropping of concrete footer pads weighing either 50 or 75 lbs (22.7 or 34 kg), and the shoveling of unearthed soil both away from and back into the footer holes.  Measurement methods for various parameters of crew member work exposure included: time synchronized heart rate monitoring with a Polar Vantage NV heart rate monitoring system used with a standard video camera, ratings of perceived exertion (RPE) using the Borg RPE scale, biomechanical analysis using the University of Michigan 3D Static Strength Prediction Program v.4.3.6, physical symptoms of discomfort using a standardized musculoskeletal survey (NIOSH Publication no.97-117), and time cycle analysis from video review.

An estimation of the force placed on the L5/S1 region of the back for a subject holding a 50 lb (22.68 kg) cement footer pad is approximately 777 lbs (352.4 kg).  Pre-intervention heart rate data collected during shoveling tasks show average heart rates ranging from 31–61 bpm higher (with peaks 52–94 bpm higher) than the lowest heart rates recorded during a five minute rest period prior to testing.  Likewise, pre-intervention average heart rates during tasks that mainly involved the use of a standard post-hole digging tool ranged from 60–73 bpm higher (with peaks 78-86 bpm higher) than the lowest baseline levels recorded.

16
Particulate Exposure Assessment of Pharmaceutical Workers Using the Wireless Video Exposure Monitoring System

Fan Xu, J. McGlothlin, Purdue University, West Lafayette, IN.

The most common risk faced by workers in the pharmaceutical industry is respiratory sensitization. Recently, highly potent drugs, like anti-cancer drugs, have been introduced, and chronic effects due to low-level exposure to these compounds are another risk for these workers. One concern is pharmacokinetics of short-term extreme exposures (peak exposures), which may be related to acute or chronic toxic health effects and have influence on the overall exposure levels. Another is the variance in exposure as a result of different work activities and behaviors in the performance of workers’ jobs. This study was aimed to investigate the exposure patterns (including peak exposures) of particulates and pharmaceutical active integrated ingredients (APIs) and correlation between exposure levels and work practices by using the new wireless Video Exposure Monitoring (VEM) system in the pharmaceutical industry. The study was conducted in a pharmaceutical research and development plant and tasks involving power material handling were selected for monitoring. Real time particulate exposure concentrations (total dust) were detected by a light scattering sensor while concurrent filter samples were collected simultaneously. In order to verify the sensor’s concurrent filter sample, a side-by-side closed-face filter sample was collected. Monitoring was running for each entire operation period. Relatively low level concentrations were found for the monitored tasks: sensor’s averages ranging from 0.5 to 10.6 μg/m³; sensor’s concurrent filter readings for API ranging from below detection limit of 0.03 to 1.43 μg/m³; and closed-face filter readings for APIs ranging from below detection limit of 0.03 to 18.1 μg/m³. Peak exposures were found to be more frequent in less control workplaces or for the operations with bad practices. Outcomes from the VEM exposure assessment approach may offer insights into control strategies including best work practices and engineering applications.

17
Improving Efficacy of a Wall-Mounted Receiving Hood by Embracing Air Curtains

Shun-Chih Wang, Chih-Chieh Chen, National Taiwan University, Taipei City, Taiwan; Cheng-Ping Chang, Institute of Occupational Safety and Health, Sijhih City, Taiwan; Shuei-Yuan Lee, An New Industrial Co. Ltd., Taipei City, Taiwan.

In most indoor workplaces, capture efficiency of a receiving hood can be reduced by cross draft around the hood opening. To improve the performance of an existing receiving hood, an average worker tends to increase volumetric flow rate of the hood, resulting a larger demand for make-up air. In this study, an energy-saving method improving efficacy of a wall-mounted receiving hood is proposed and tested by air flow visualization to show that lower operation cost and higher efficacy can be possible with an additional engineering control measure. A wall-mounted receiving hood is installed above a laboratory bench to simulate a kitchen range hood. A liquid with 4% of olive oil and 96% of pure water is emulsified and aerosolized by a supersonic device to produce the aerosol simulating airborne particulates generated from cooking operation. A rectangular space is enclosed by opening of the receiving hood, three linear air curtains embracing the emission source of water-oil aerosol, the wall which the receiving hood is mounted on, and the laboratory bench surface where the linear air curtain devices are put on. The upward blowing speed of air curtains and suction speed on the hood opening are adjusted to minimize the need of make-up air. Air flow visualization is enabled by a laser light sheet generator. In air flow visualization tests, it is found that, with less make-up air needed, the dispersion of aerosol can be well constrained in the rectangular space. This means the indoor space adjacent to the receiving hood can be better protected from oil contamination, and the operation cost of air-conditioning system can be reduced.

18
An Examination of Observations and Incidence Rates for a Behavior Based Safety Program

R. Agraz-Boeneker, W. Groves, J. Haight, The Pennsylvania State University, University Park, PA.

This study was developed in cooperation with an oil platform located off the coast of Angola.  A Behavior Based Safety (BBS) program called BASIC (Behavioral Approach to Safety Improvement in Cabinda) has been in place at this 200-employee location since January 2002.  All observation reports for 2003 were made available to explore relationships between behaviors recorded and incidence rates.  A random sample of 382 observation reports was selected from the total set of 64,643 recorded in the period.  Information extracted included the number and type of “safe” and “at-risk” behaviors observed daily, and the total number of daily observation reports completed.  Relationships between the number of daily observation reports, the number and type of behaviors recorded, and four types of incidents – Injuries, Fires, Spills, and Near-Misses – were examined using a statistical model applying Ordinal Logistic Regression:

Y =B1*OW + B2*X1 + B3*X2 + error

where Y is an ordinal variable representing the probability of having an incident, OW is the average number of daily observations, X1 and X2 are the number of observed “safe” and “at-risk” behaviors, respectively, and B1, B2, and B3 are the regression coefficients. Analysis showed that none of the regression coefficients was statistically significant (p-value>0.05, Nagelkerke R-Square=0.015) and the null hypothesis that no relationship exists between the variables was accepted.  Therefore, making more or fewer observations per day did not affect the outcome. With the number of daily observations ranging from 89 to 349 and each requiring approximately 15 minutes, the human resource commitment is significant and management should give consideration to the current allocation of resources.  It should be noted that a limited time frame was examined and further that the results of this work represent only one site of those using BASIC.  Generalization of this approach to other BBS programs is being examined.

19
Validation of the Inhalation Component of a Qualitative Exposure Assessment Model

L. Elliott, R. Oestenstad, The University of Alabama at Birmingham, Birmingham, AL.

Various qualitative exposure assessment models based on different underlying assumptions, requiring distinct inputs, and providing diverse outputs have gained in popularity over the past decade. Although a wide variety of exposure assessment models are available, most models have not been validated.  This study compared the inhalation risk factor of a Qualitative Exposure Assessment (QLEA) model with quantitative monitoring data collected at a U.S. manufacturing facility over the past nine years for twelve Similar Exposure Groups (SEGs).  The maximum measured concentration was used for the comparison.  A Spearman’s Rho Correlation found no significant correlation between the model’s risk factor and the maximum measured exposure (r_s=0.235, p=0.174). A Chi Square analysis, using the Fisher’s exact test, found that the maximum measured inhalation exposure was independent of the QLEA inhalation risk factor (χ²=0.203, p=0.653).  The model accurately predicted the true exposure in 21 out of 35 cases (60% efficiency).  Sixty-one percent of the true acceptable exposures were correctly predicted by the model (sensitivity), while 58% of the true unacceptable exposures were correctly predicted by the model (specificity).  In addition, there was a 42% probability that the model would result in a false negative prediction and a 39% probability that the model would result in a false positive prediction.  These results indicate that the inhalation risk factor from the QLEA model does not appear to be an accurate predictor of true inhalation exposures.

20
Hearing Sensitivity of Workers Enrolled in a Hearing Conservation Program Based on a Conservative Classification of 85 dBA Criterion/3dB Doubling Noise Exposure Data

M. Norman, R. Oestenstad, The University of Alabama at Birmingham, Birmingham, AL.

This study was conducted to determine changes in hearing sensitivity of workers prior to being included in an industrial hearing conservation program due to adoption of measuring noise exposure by the 85 dBA criteria and 3 dB doubling rate as recommended by ACGIH and NIOSH, and a conservative statistical method of classifying group noise exposures.  Hearing threshold levels of these workers measured in 1987 and 2001 were compared to predicted hearing thresholds by age and race according to ANSI S3.44-1996.  Predicted noise-induced permanent threshold shifts were also calculated according to S3.44-1996 based on the workers’ 90 dBA/5dB doubling measured noise exposures during the study period. Of the 675 workers invited to interviewed, only 231 agreed to participate. Noise exposure and audiometric data for these workers were abstracted from the organization’s personnel and industrial hygiene databases.  An additional 200 workers were lost to the study due to missing data or questionable audiometric records.  Exposure histories for the remaining 31 subjects were developed from the employment records and noise exposure data.  The running equivalent noise exposures for these workers during the project period ranged from 71 – 87 dBA with a mean of 80 dBA.  Measured hearing threshold levels for this group were greater than the predicted levels at all audiometric frequencies at the beginning and end of the study, and those differences did not significantly change over the study period.  Calculated noise-induced permanent threshold shifts based on the running equivalent noise exposures were found to be not significantly different from zero. Therefore, it was concluded that hearing threshold changes in the study group were not related to occupational noise exposure, and inclusion into the hearing conservation program would not be efficacious.

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Dermal Exposure to JP-8 Significantly Contributes to Production of Urinary Naphthols

E. Chao, L. Kupper, B. Serdar, P. Egeghy, S. Rappaport, L. Nylander-French, The University of North Carolina at Chapel Hill, Chapel Hill, NC.

We investigated the contribution of dermal and inhalation exposure to JP-8 to the total body dose using naphthalene as a marker.  Dermal exposure measurements were obtained using tape-strip sampling and inhalation exposure measurements were obtained by passive monitoring (breathing-zone concentration).  Both end-of-exposure and post-exposure breath measurements collected by the glass bulbs were used as the breath biomarkers of JP-8 exposure.  Urinary 1-naphthol and 2-naphthol were used as urinary biomarkers of JP-8 exposure and metabolism.  Multiple regression analyses were conducted to investigate the relative contribution of dermal and inhalation exposure to JP-8 as well as smoking and job titles to breath naphthalene and urinary 1-naphthol and 2-naphthol levels.  The relative contribution of predictors to the total body dose was also determined.  Our results show that dermal exposure to naphthalene (P = 0.0129), in addition to inhalation exposure to naphthalene, smoking and job title (all P ≤ 0.0095), significantly contributed to the total body dose (both breath and urine).  Contribution of dermal exposure to the total body dose were observed to be the most important exposure route to breath naphthalene and greater to levels of urinary 2-naphthol than to urinary 1-naphthol.  We conclude that dermal exposure to JP-8 contributes significantly to breath naphthalene and urinary 1-naphthol and 2-naphthol levels and, in some instances, skin might be the primary route for exposure.  Furthermore, the efficiency and suitability of the tape-strip technique for the assessment of dermal exposure to and uptake of JP-8 and its components is established.  We recommend that dermal exposure monitoring by the tape-strip technique be performed in conjunction with biological monitoring when assessing JP-8 exposure.  Future work on dermal toxicokinetic and pharmacologic studies are warranted in order to gain additional knowledge on naphthalene metabolism involving various cytochrome P450s, epoxide hydrolases, and glutathione S-transferases in the skin.

22
Particle Investigation in the Near-Wake of an Elliptical Cylinder to Predict Exposure

K. Pickett, M. Flynn, Y. Koto, T. Anthony, The University of North Carolina at Chapel Hill, Chapel Hill, NC.

Wind tunnel experiments were conducted to investigate size-specific particle concentrations in the near-wake of a worker facing downstream.  An elliptical cylinder, 0.86 m tall with major and minor axes of 0.172 m and 0.09675 m, respectively, served as the human surrogate. The freestream velocity (1.2 m/s) was perpendicular to the major axis resulting in a Reynolds number of approximately 13,600.  An ultrasonic atomizer was placed downstream of the cylinder, inside the wake, to generate a poly-dispersed liquid aerosol. Cascade impactors were used to determine the atomizer mass generation rate and aerosol concentrations for 6.3 – 9.7 mm oil particles. The mass generation rate was 7.2 mg/s for this size range, representing 67.2 % of the generated oil particles in the respirable size range. Particle concentrations were measured at three locations in the near-wake of the cylinder: the breathing, elbow, and hip regions. The concentrations were expressed as dimensionless numbers relating concentration to the atomizer mass generation rate (m_o), the height (H) and breadth (D) of the cylinder, and the freestream velocity (U). The dimensionless results were 6.7, 65.5, and 4.3 for the breathing, elbow, and hip regions, respectively. The dimensionless concentrations for the breathing zone and hip region showed good agreement with sulfur hexafluoride (SF₆) tracer gas concentrations measured within the near-wake of an anthropometric mannequin, as expected for small particles. However, higher particle concentrations in the elbow region were identified and attributed to the geometric differences between the cylinder and bent mannequin elbows. For a worker facing downstream, a dimensionless breathing zone concentration of 7.0 is a logical estimation for respirable aerosols generated in the wake. The primary significance of the work is extending a simple model of human exposure to aerosols, and providing a simple estimator for assessment and control studies.

23
Indirect Adjustment for Confounding in a Retrospective Occupational Cohort Study

C. Trent, D. Loomis, The University of North Carolina at Chapel Hill, Chapel Hill, NC.

Retrospective occupational cohort studies often lack prevalence data on potential confounders that could limit the interpretation of study results.  Consequently, investigators may rely on surrogate prevalence data to adjust indirectly for the confounder.  A confounding relative risk (RR_co) can be determined from the surrogate prevalence data and the background risk of the disease.  Using the RR_co and the observed RR (RR_obs), an adjusted RR (RR_adj) is obtained using RR_adj = RR_obs/RR_co.   The underlying assumption is that the confounder prevalence estimated from the surrogate population is representative of the study population, but this may not be the case.  

We examined the prevalence of smoking and the effect on RR_co for a historical cohort of asbestos textile workers (n=744) distributed among four plants in North Carolina (NC) and one in New Hampshire (NH).  The prevalence of smoking at each plant was estimated through a review of data from questionnaires administered during 1965-1966.  Prevalence data for an unexposed referent group was obtained from a published national survey.  We calculated RR_co ranging from 1.47-1.87 for the four NC plants and 1.48 for the NH plant, using white-collar workers as the unexposed referent group.  When non-asbestos textile workers were used as the referent group, the RR_co ranged from 1.16-1.47 for NC plants and 1.16 for the NH plant.  Additionally, when blue-collar workers from the survey were used as a surrogate exposed population for asbestos textile workers, RR_co ranged from 1.20-1.41 with white-collar as the referent group. 

These results demonstrate that when cohort-specific information on confounder prevalence is lacking, selection of an appropriate surrogate population is important.  Data from surveys of other workers may provide biased prevalence estimates.  Even within cohorts similar in industry, geography and time, variability in the prevalence of smoking is significant and can affect the ability to control confounding by indirect adjustment.

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Determinants of Airborne Fungal Concentration Within Wood-Framed Buildings in a Temperate Climate

V. Arrandale, S. Kennedy , K. Bartlett, D. Bell, University of British Columbia, Vancouver,  BC, Canada.

Aims: To identify the determinants of viable airborne fungal concentration within wood framed buildings in a temperate climate for the purposes of prioritizing fungal abatement projects.

Methods: Viable airborne fungal samples were collected with a SAS Super 100 sampler at sixty-seven buildings.  At each building a sample was collected in three locations: indoors, outdoors and in the crawlspace.  Samples were identified to genus level for Cladosporium, Aspergillus, and Penicillium genera.  Other fungal colonies were identified as sterile mycelia, yeast or “other”.  Covariate data collected for each of the buildings included temperature, relative humidity, visible moisture, floor material, visible mould, and whether the space was open to the outdoors.

Results:  Geometric mean airborne fungal concentrations were significantly different between the sample locations: indoor 156CFU/m³ (GSD=2.5) < outdoor 529CFU/m³ (GSD=2.4) < crawlspace 1118CFU/m³ (GSD=4.6).  For each of the identified fungal genera and groupings the indoor environment was significantly correlated with the crawlspace environment.  Buildings with a dirt floor in the crawlspace had significantly greater crawlspace total airborne fungal concentrations (GM=1864 CFU/m³) compared to buildings with concrete crawlspace floors (GM=396CFU/m³, p=0.005).  Together, an opening to the outdoors (open windows indoors or vents in crawlspace) and a dirt crawlspace floor were predictive of both crawlspace (R² = 0.368) and indoor (R² = 0.232) airborne fungal concentration in multiple regression models.

Conclusion:  Wood framed buildings with a dirt floor in the crawlspace are at risk of elevated viable airborne fungal concentration both in the crawlspace and in the indoor environment.  Crawlspaces that are open to the outdoor environment and indoor spaces that rely on natural ventilation are also at risk of elevated viable airborne fungal concentrations.

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Establishing Baseline Exposures to Hydrocarbons and Noise at a Synthetic Crude Oil Upgrader/Refinery

M. Green, H. Davies, University of British Columbia, Vancouver, B.C., Canada

Background: Noise dosimetry was conducted simultaneously with personal hydrocarbon sampling at a large petroleum complex located in northern Alberta, Canada, that consists of a newly built heavy-oil upgrader and a pre-existing refinery. Upgraders process ‘diluted bitumen’ (extremely thick crude that is mined rather than drilled) to produce ‘synthetic crude oil’, in this case via a process known as ‘heavy hydrotreating’. Monitoring was conducted to develop exposure baselines for the new upgrader and recently modified refinery. Workers worked 8,10, or 12 hour shifts (principally the latter).

Methods: Hydrocarbons were sampled using a modified version of NIOSH methods 1500/1501, utilizing 600 mg charcoal sorbent tubes. Noise exposures were measured using personal noise dosimeters set to an 85 dBA criterion level and a 3 dB exchange rate. Workers selected by ‘convenience sampling’ wore both devices simultaneously in a belt-mounted pump-pouch; sample durations were 6-7 hours. 

Results: 61 hydrocarbon and 65 noise samples were collected. All n-hexane and BETX results (the focus of the study) were less than 5% of their exposure limits. Geometric mean exposures in parts-per-billion (ppb) were: benzene 0.7ppb, ethylbenzene 0.4ppb, toluene 3.8ppb, xylenes 1.3ppb, and n-hexane 3.6ppb. The mean equivalent continuous noise level (Leq, 12 hr) was 85.7 dBA, with individual Leq’s ranging from 79.3 to 95.5 dBA.

Discussion: These very low measurements demonstrate the levels of exposure that are achievable in a modern refinery/upgrader setting. Hydrocarbon measurements may be biased by the short sampling duration and lack of sampling during night shifts that may not have captured the entire range of exposures. These limitations also apply to the noise dosimetry results. With one exception, all process units had Leq’s in excess of the 12-hour unprotected exposure limit (83 dBA in Alberta), thus these results justify the mandatory hearing protection rule in place at the facility.

26
Evaluation of Exposure to Cryptococcus neoformans var. gattii Among Arborists and Landscapers

A. Hingston, K. Bartlett, H. Davies, H. Ward, University of British Columbia, Vancouver, BC, Canada

Cryptococcus neoformans var. gattii (CVG) has emerged as an infectious pathogen on Vancouver Island, BC. Since the first diagnosis in 1999 there have been 120 confirmed human cases of Cryptococcosis.

In May 2002, air samples were taken under a colonized tree and a significant number of airborne CVG were recovered (1080 CFU/m³). The goal of this research is to describe exposure to CVG among workers who work outdoors under the canopies of trees on Vancouver Island.

Environmental sampling of trees, soil, water and air has been used to characterize geographical distribution of the organism. Air sampling in the breathing zone of workers performing woodland tasks were taken.

Sampling results suggest that this organism can be found in varying concentrations on Vancouver Island from Victoria in the south to Courtenay in the north. . The highest concentrations of positive samples have been found in Parkesville (31%), Little Qualicum (24%), and Port Alberni (22%). Results also suggest that a wide range of tree species have been colonized including economically important varieties such as Douglas fir, Cedar, and Alder. Air sampling results show mean concentrations of greater than 10cfu/m³ in the drier months (April to October) with virtually no positive air samples being found in wetter months (November to March). Air samples also indicate that the majority (>75%) of airborne propagules were found to have an aerodynamic diameter greater than 3.3μm. However chain sawing increased both the total concentration and the percentage of propagules of less than 3.3μm.

There is a risk of occupational exposure to CVG. The risk of exposure is higher in the drier months of the year and when the worker performs tasks that create aerosols. Workers should be aware of the existence of the pathogen and the signs and symptoms of disease.

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Metal Working Fluid Assessment at the Coast Mountain Bus Company Fleet Overhaul Center

C. Lynch, K. Bartlett, University of British Columbia, Vancouver, BC, Canada

The goals of this study were to evaluate exposures to aerosolized metal working fluid (MWF) and to assess the efficacy of the MWF maintenance program in a transit bus service centre. A range of respiratory effects has been linked to inhalation exposures of specific MWF components, including immunological responses to gram-negative bacteria. Research has shown that bacterial growth is encouraged when fluid maintenance programs do not efficiently control coolant temperature, pH levels, and tramp oil accumulation.

Eighteen full shift personal breathing zone samples were obtained from nine machinists. Samples were collected in accordance with NIOSH Method #5524. Nineteen bulk MWF samples were evaluated for pH, coolant concentration, tramp oil concentration, temperature. Six subsequent bulk samples were taken for endotoxin analysis from selected machines

None of personal samples exceeded the 0.5 mg/m³ REL for total mass, although one sample was above the action level. The mean exposure was 0.17 mg/m³, ranging from 0.08 mg/m³ to 0.28 mg/m³ with an upper confidence limit of 0.20 mg/m³.  Fourteen machine reservoirs demonstrated tramp oil accumulation of 5% to 12% by volume. Reservoir temperatures ranged from 20˙C-26˙C. The pH levels of 14 machines were outside manufacturers specifications. Nine machines had coolant concentrations outside of specified levels.  Endotoxin levels ranged from 33 EU/ml to 7901 EU/ml with no association to machine fluid factors.

Airborne exposures to MWF were within compliance. Bulk MWF analysis demonstrated the current fluid maintenance program was not adequate. The coolant concentration, tramp oil accumulation, and pH levels were neither monitored nor controlled, allowing microbiologic proliferation within the reservoirs.

1. Develop a comprehensive MWF maintenance program. 2. Implement an ongoing risk communication program specifically addressing MWF exposures. 3. Undertake periodic exposure monitoring to monitor temporal and process changes, and include a dermal exposure assessment.

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The Use of a Model Incorporating Terrain Effects for the Prediction of the Dispersion From a Chemical Release: The Influence of Weather Conditions on the Time Available for Emergency Response

C. Adkins, S. Clark, University of Cincinnati, Cincinnati, OH; M. Gunn, Retired, Cincinnati, OH

Weather affects the movement of chemicals upon release.  Wind speed and direction, as well as air and ground temperatures play a role in the dispersion of a plume.  The purpose of this study was to determine the amount of time from release to the build-up of harmful concentrations in populated areas. The value of this effort is to provide emergency personnel the maximum amount of time available to communicate emergency information to the public (i.e. evacuation or “shelter in place” notification).  Using the Release Incorporating Terrain Effects (RITE) Emergency Response model, which incorporates the topography of Hamilton County, OH, hypothetical releases were modeled.  The scenarios modeled include the release of hydrogen cyanide from a rail car.  This same scenario was repeated with chlorine and with ammonia in order to compare the effects of the weather parameters on the plumes of different chemicals.  By incorporating various weather parameters, based on weather conditions archived by the National Climatic Data Center (NCDC), the time for plume movement, from several hypothetical release scenarios, to reach areas of public congregation (housing communities, shopping areas, recreational areas, etc.) was analyzed.  Weather parameters significantly influence the time for plume travel, as well as the spatial movement of the plume.  The time available for emergency response varied widely, depending upon weather conditions and release scenarios, and ranged from 10 to 40 minutes. It would be a challenge for many emergency response organizations to perform the necessary communications and other actions within the available time for some of these conditions.

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(1-3)-b-D-glucan as a Surrogate for Mold Exposure

Y. Iossifova, T. Reponen, D. Bernstein, H. Kalra, University of Cincinnati, Cincinnati, OH; A. Masino, K. Hershey, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH.

(1-3)-b-D-glucan in mold is a recognized potentiator of airway inflammatory responses. Currently there are two methods available for the analysis of (1-3)-b-D-glucan: the Limulus Amebocyte Lysate assay (LAL) and the inhibition Enzyme Immunoassay (EIA). Both methods are used for the analysis of air samples, however, only EIA assay has previously been used for settled dust samples. The objective of this study was to compare the specificity of these two methods for the analysis of (1-3)-b-D-glucan as a surrogate for mold exposure in dust and air samples. A total of 41 indoor air and 39 dust samples were collected. All samples were assayed by the LAL and EIA for (1-3)-b-D-glucan concentrations. As a reference, dust samples were also analyzed by the traditional culture-based assay using DG-18 medium to obtain total and mold genera culturable count (CFU), and by the immunochemical analysis for Alternaria and Aspergillus antigens. Microscopic spore count was performed as a reference for air samples. Data were analyzed by the Spearman Non-Parametric correlation and the Wilcoxon signed ranks test. The Wilcoxon test indicated a statistically significant difference between the LAL and EIA tests in dust samples only (z= -2.107, p=0.035). A significant correlation between LAL and EIA (p=0.016) was found in air samples only. Dust samples had a significant correlation between LAL-analyzed (1-3)-b-D-glucan and the concentration of Alternaria antigen (p=0.009); the CFU of Cladosporium (p=0.016) and yeasts (p=0.007). Even better correlation was found with the combined CFU of Penicillium, Aspergillus, Cladosporium and yeasts (p=0.003). In air samples, LAL analyzed (1-3)-b-D-glucan correlated with the total count of Aspergillus/Penicillium (p=0.02) and Cladosporium (p=0.006). No significant correlation was found between EIA analyzed (1-3)-b-D-glucan and the results obtained by the reference methods in either dust or air. These data suggest that the LAL-analyzed (1-3)-b-D-glucan is a better predictor of mold concentration.

30
The Impact of Human Discriminability and Vantage Point on Video Based Ergonomic Risk Assessment

S. Kotowski, K. Davis, University of Cincinnati, Cincinnati, OH.

Video based postural risk measurement techniques require ergonomists to make subjective judgments of postures. These assessments have raters compare work postures to known benchmarks (deemed risky).  However, little is known about the capability of raters to identify postures relative to these benchmarks. In order to determine the discriminability of raters, twenty individuals observed photos of wrist postures from 70 ^o flexion to 70 ^o extension (10^o increments) and 35 ^o radial deviation to 35 ^o ulnar deviation (5^o increments) from three different vantage points: front (perpendicular to the sagittal plane), side (perpendicular to the lateral plane), and oblique (bisects the sagittal and lateral planes). Additionally, the effectiveness of a picture to assist the rater was evaluated on half of the pictures. In all, each observer viewed 180 photos (30 wrist postures, 3 views, with and without pictures). Observers compared postures to the following benchmarks: 15^o for radial/ulnar deviation and 30^o for flexion/extension. A higher percentage of flexion/extension postures were classified correctly than radial/ulnar postures (83% vs. 61%, respectively). The camera view significantly (p<0.05) impacted the percentage of correctly classified postures with the best views being the oblique view for flexion/extension and the front view for radial/ulnar deviation. Neither gender, rater experience, nor the presence of a picture was significant. As expected, misclassification was greatest when postures were close to the cutoff value for flexion/extension. Interestingly, misclassification was greatest for the more neutral ulnar postures and for the more deviated radial postures, regardless of vantage point. The results indicate observers maybe misclassifying wrist postures up to 40% of the time, potentially leading to an inaccurate assessment of risk of musculoskeletal strain. To minimize the potential for misclassification, observers should consider view relative to the target wrist posture and be particularly cognizant of the postures assessed relative to the benchmarks.

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Indoor and Outdoor Concentration Levels of Airborne Fungi in Cincinnati Area Homes: Pilot Study

T. Lee, D. Martuzevicius, C. Crawford, A. Adhikari, T. Reponen, S. Grinshpun, University of Cincinnati, Cincinnati, OH.

Due to the adverse health effect of fungi in occupational and non-occupational environments, a public interest has been increased to the assessment of human exposure to airborne fungal spores.

In this study, indoor and outdoor concentrations of total and culturable fungi were measured using the Button Personal Inhalable Aerosol Sampler in six single-family homes located in the Greater Cincinnati. The selected homes had neither visible mold nor moisture damage.  In each home, 24-hour air sampling was conducted indoors and outdoors during five consecutive days in spring and fall (overall, 10 pairs of samples taken in each home). The samples were analyzed using total and culture-based methods and identified to the genus/group level. The indoor and outdoor median concentrations of total fungal spores were 405 and 1182 spores m^-3 in spring and 120 and 1372 spores m^-3 in fall. The most predominant fungi was Aspergillus/Penicillium followed by Cladosporium, Ascospores, and Basidiospores in both spring and fall seasons. The indoor and outdoor median concentrations of viable fungi were respectively 88 and 194 CFU m^-3 in spring and 205 and 437 CFU m^-3 in fall. Cladosporium, non-sporulating fungi, Penicillium, and Aspergillus were among prevalent culturable fungi. Indoor/Outdoor (I/O) ratios of total fungal spores were between 0.03 and 2.69 in spring and 0.01 and 0.69 in fall. The I/O ratio of culturable fungi ranged from 0.05 to 53.34 in spring and 0.04 to 1.69 in fall.

A positive correlation was observed between indoor and outdoor fungi. The Spearman correlation coefficients were respectively 0.396 and 0.845 for total fungi in spring and fall, and 0.665 and 0.687 for culturable fungi in spring and fall (p<0.05).  This indicated that outdoor air was the main source for fungal spores in these homes. I/O ratios of viable fungi were greater than those of total fungi in both seasons.

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Estimating Chemical Exposure in an Uranium Enrichment, Gaseous Diffusion Plant

A. Moser, K. Hahn, C. Rice, R. Hornung, University of Cincinnati, Cincinnati, OH; D. Tollerud, University of Louisville, Louisville KY.

Radiation exposures have been studied at many nuclear facilities including uranium enrichment plants; however, previous studies have not examined an extensive list of chemical exposures, limiting evaluation of potential interactions with radiological exposures.  This project is the initial step to develop working lifetime exposures to arsenic, beryllium, hexavalent chromium, nickel, uranium metal, and trichloroethylene, for employees at a gaseous diffusion plant.   These agents of interest were chosen based on carcinogenicity and a needs assessment previously conducted.  This information will be used in a cohort cancer study to evaluate exposure-response.

The facility began operation in 1952 and has continuously produced enriched uranium.  This plant site includes 161 buildings; most have been used for the same purpose since construction.  Three major process modifications/renovations have occurred. 

An original list of 2,150 unique job titles was reduced to 46 grouped job titles, and a group of job titles that are reasonably expected to have no exposure.  This grouping was reviewed by long-term workers and site personnel and modified as necessary.  Next a Job Exposure Matrix (JEM) was developed by ranking the exposure of each group from 0 (none to minimal) to 5 (highly probable) for agents of interest.  These values were allowed to change over time as job duties changed (e.g., security personnel originally visited each building and potentially received low exposure to all agents, but later walked the perimeter fence where there was minimal to no exposure). This JEM will be supplemented with quantitative data as it becomes available.  This process of developing a JEM for multiple chemical exposures can be followed at other gaseous diffusion plants.

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Long-term Sampling of Airborne Fungal Spores in Indoor Environments

M. Osborne, T. Reponen, A. Adhikari, S. Cho, S. Grinshpun, University of Cincinnati, Cincinnati, OH.

Because we live in a society where the majority of our time is spent indoors, the quality of indoor air has become increasingly important.  Specific attention has been drawn to airborne fungal spores as a factor affecting indoor air quality.  Most studies have measured the concentration of aerosolized fungi using short-term sampling techniques combined with culture-based analytical methods.  Shortcomings of both approaches have been addressed through implementing long-term sampling and microscopy-based spore enumeration.  Long-term sampling allows investigators to obtain an integrated background concentration value that can be used for comparison purposes in problem homes.  Additionally, the lack of research on long-term sampling methods in indoor environments has prompted a need to investigate these methods in more detail.  In this study, fungal spore samples were collected using a Button Personal Inhalable Sampler (SKC, Inc.) for 48 hours at a flow rate of 4 L min^-1.  The sampling was conducted in 140 homes either in the spring (March-May) or the fall (August-October).  Samples were analyzed using microscopy-based total counting and identified to the genus/group level.  Homes were classified as moldy or non-moldy based on visible mold and moldy odor, which were assessed in a home walkthrough.  Overall, concentrations varied widely, between 0 and 2,294 spores m^-3.  The concentration in the spring (geometric mean [GM]= 69 spores m^-3; geometric standard deviation [GSD]= 4 spores m^-3) was found to be significantly lower than that in the fall (GM = 232; GSD = 3) (t-test: p<0.001). Preliminary data analysis did not reveal any statistically significant differences in the fungal spore concentration between moldy and non-moldy homes (either when classified based on visible mold or moldy odor).  It appears that the seasonal variation masked the difference between mold-contaminated and non-contaminated homes.

34
A New Field Compatible Method for the Collection of Fungal Fragments

S.-C. Seo, T. Reponen, S.-H. Cho, Y. Iossifova, S. Grinshpun, University of Cincinnati, Cincinnati, OH.

It is well known that fungal propagules can cause adverse health effects on humans. However, no clear cause-and-effect relationship has yet been established. Recently, we have shown that fungal fragments are released from contaminated surfaces together with microbial spores. The small size, large quantity, and toxicological characteristics make these particles potential contributors to the adverse health effects. In order to quantitatively investigate health effects associated with fungal fragments, it is essential to collect pure fragments. Cascade impactor has often been used for size-selective sampling of airborne particles. However, we found microbial spores to be prone to bouncing from upper to lower stages making the differentiation of fragments and spores difficult. Therefore, we developed a new fragment collection system consisting of two sharp-cut cyclones (PM2.5 and PM1.0) and a filter sampler. They are connected to each other in sequence, so that the spores will be captured in the PM2.5 cyclone, the mixture of spores and fragments will end up in the PM1.0 cyclone, and pure fragments will be collected onto a polycarbonate filter. Two optical particle counters and two fine particle counters are utilized to measure the total number of collected spores and fragments, respectively. The system was tested with monodisperse PSL particles (0.54, 1.79, and 3.94µm) and two fungi: Aspergillus versicolor and Stachybotrys chartarum. This test confirmed the cut-sizes for the two cyclones: 2.5 and 1.0 µm, respectively. When testing with fungi, microscopic counting of the fragment samples showed no spores on the fragment filter confirming that the system effectively separates fragments from spores. Preliminary β-glucan analysis showed concentrations of 12 ng/m³ for spores, 9 ng/m³ for the mixture of spores and fragments, and 6 ng/m³ for pure fragments. The study proves that the sampling method is a promising tool for collecting fungal fragments and spores in future studies.

35
Work and Life Measures of Injuries and Illnesses

L. Brown, R. Sokas, K. Rospenda, University of Illinois at Chicago, Chicago, IL.

According to the 2003 United States Bureau of Labor Statistics data, there were 4,365,200 recordable occupational injuries and illnesses reported for those industries required to maintain such information. Of those 4.3 million injury and illness cases, approximately 30% of them resulted in lost-work days. In 2003, we conducted a random-digit telephone survey of 2,151 working Americans in an attempt to identify variables that could predict and/or explain the likelihood of negative health outcomes as they relate to perceived work conditions and the work environment. The questionnaire focused on participants’ perception of job satisfaction, positive work experiences, job stressors, personal life stressors, occupational injuries and illnesses, general workplace harassment, including sexual harassment on the job. The coping measures addressed alcohol use, the presence of social networks in the workplace and in their personal lives, positive and adverse lifestyle measures and the availability of professional counseling services.

The study data shows that 325 (15.1%) of the 2,151 study participants reported that they had experienced an occupational injury or illness within the twelve months prior to the interview while 50.3% of that population reported that their occupational injury or illness resulted in lost-work days (LWD). The data also showed that participants who answered “yes” to “my job is nerve wracking” were more likely to report a LWD injury/illness (32.9%) versus those that answered “no” at (23.1%). Of the participants that reported LWD’s, 13.9% reported having “serious problems with close relatives,” while 18.9% reported that a close relative suffered from serious injuries in the twelve months prior to the interview. The data obtained as a result of this study supports the hypothesis that the severity of occupational injuries and illnesses are related to the complex relationship between both personal life stressors and job stressors.

36
Laboratory Animal Allergen, Endotoxin, and Particulate Matter Production and Modeling in a Working Animal Research Facility

L. Chen, L. Conroy, T. Schoonover, S. Dorevitch, J. Artwohl,  University of Illinois at Chicago, Chicago, IL.

More than 2 million workers in the US are exposed to laboratory animals in the workplace. Almost one-third of the 20-50% of workers who report symptoms related to laboratory animal exposure have lost workdays or were permanently removed from their jobs. Past studies have shown that allergens are not the sole cause for these work-related symptoms, but other environmental trigger(s) may be responsible, such as endotoxins and/or particulate matter (PM).  The objectives of this study are to 1) determine emission factors for male and female mice for particulate matter, endotoxin, and allergen (mus-m-1) in a mouse chamber under controlled conditions,

 2) apply emission factors to a working mouse room to predict room concentrations, and 3) compare predicted with measured concentrations.  Mouse allergens, endotoxins, and PM were collected daily over seven days in a working animal laboratory facility. Separately, a leak-proof, acrylic chamber was constructed with PVC inlet and fitted with cassette holders and five mice were placed inside the chamber.

 Filtered air was drawn through the chamber to provide at least 15 air changes per hour to collect the mouse allergen, endotoxins, and PM produced. The samples were analyzed using gravimetric weighting, LAL and ELISA assay for PM, endotoxin and allergen, respectively.  The emission factor per mouse for PM ranged from 0.0236 ug/min to 0.919 ug/min with a mean of 0.497 ug/min.  Emission factor per mouse for endotoxin ranged from 0.093 endotoxin units (EU)/min to 0.502 EU/min with a mean of 0.314 EU/min. Allergen analysis is still on-going. Determining emission factors for endotoxin, allergens, and PM will allow the emission factors, to be applied to a predictive concentration model for other animal facilities.  Ultimately, this information can be used in future studies to estimate worker exposure and evaluate the effects of additional exposure control measures.

37
Design, Testing, and Validation of an Exposure Chamber for Welding Fume Emission Characterization Studies

S. Durgam, S. Erdal, L.M. Conroy, P.  Scheff, L. Berman, University of Illinois at Chicago, Chicago, IL.

In the United States, there are over 185,000 welders and an additional 700,000 workers who perform some type of welding in their jobs. To understand the relationship between dose-response and human health effects requires detailed information on welding fume composition. The goal of this study is to design, test, and validate an exposure chamber to measure welding fume composition, welding fume emission rates and factors unique to a welding process. The chamber has been designed based on isokinetic sampling principle to ensure collection of representative aerosol samples from the chamber. The conical and straight duct sections are the two key components. The sampling section along with orifice plate and blast gate has been incorporated into the system by using flanges. In order to estimate wall losses, quantification of components in the total mass balance of the chamber is required. The electrodes and base metal were pre and post-weighed after first run. Wipe samples were taken at representative sections in the conical hood and straight duct section. This would be extrapolated to estimate the wall losses in the entire chamber. System performance was verified by performing welding in the chamber using E7018 and E6010 electrodes and by comparing the literature-based values for emission factors with those obtained from our experimental system. The chamber performance was also assessed by using Vibrating Orifice Aerosol Generator to release monodisperse aerosols in the system, and comparing concentration of different size particles generated to the samples collected under isokinetic conditions.  The straight duct section air flow was turbulent and fully developed with a characteristic flat profile. The pressure drop across the orifice was characterized to ensure a constant air flow rate in the system. Leak test using SF6 was performed to ensure total capture of gases emanating during the experiments with a mixing factor of 1.

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Prevalence of Wheezing Illness in Three Cities in the Ukraine

M. Matwyshyn-Fuoco, D. Hryhorczuk, I. Dardynskaia, University of Illinois at Chicago, Chicago, IL; Z. Shkyryak-Nyzhnyk, Y. Antipkin, Academy of Medical Science of Ukraine, Kyiv, Ukraine; A. Zvinchuk, University of Illinois Data Management Center, Kyiv, Ukraine

Asthma is the most common chronic illness found in children, with increasing global prevalence and morbidity.  ISAAC, the International Study of Asthma and Allergies in Childhood, has defined “wheezing or whistling in the chest” as the key symptom of asthma.  International comparisons of asthma prevalence between countries are largely based on the prevalence of wheezing as measured by the ISAAC questionnaire.  We sought to measure the prevalence of wheezing illness in 7 year old children in 3 cities in Ukraine undergoing various degrees of westernization and economic transition.  In 2002 we administered the ISAAC questionnaire to 2,130 children: 1156 in Dniprodzerzhinsk, 316 in Kyiv, and 705 in Marioupol, who were participants in the Family and Children of Ukraine longitudinal cohort study.  Wheezing was defined as a positive answer to "Has your child/Have you had wheezing or whistling in the chest in the last 12 months?"  The prevalence of wheezing illness among these 7 year old children was 5.7% in Dniprodzerzhinsk, 9.9% in Marioupol, and 14.4% in Kyiv Left Bank.  The prevalence of wheezing illness was highest in Kyiv, Ukraine’s capital and the most westernized city, followed by Marioupol and Dniprodzerzhinsk.  The prevalence rate for wheezing in Kyiv (14.4%) is higher than the global rate (11.8%), and comparable to the North American regional rate (17.6%).   The prevalence rate in Dniprodzerzhinsk (5.7%) is lower than the regional rate for Western Europe (8.1%); the prevalence rate in Marioupol (9.9%) is higher than the regional rates of Western Europe (8.1%), and Northern and Eastern Europe (8.8%).  These data are consistent with the hypothesis that increasing “westernization” is associated with increasing prevalence of childhood asthma.

This project was supported by NIH Research Grant # D43 TW00653 funded by the Fogarty International Center, NIEHS, NIOSH, and the Agency for Toxic Substances and Disease Registry.

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Exposure to VOC at an Aluminum Rolling Mill Using Bio- and Petroleum-Based Lubricants

M. Mesones, P. Scheff, T. Theis, S. Miller, L. Conrroy, T. Schoonover, R. Malcolm, University of Illinois at Chicago, Chicago IL.

Current aluminum rolling practice results in significant losses (40-80%) of lubricants through volatilization. Under normal operation, most of the emissions are expected to be collected by fume hoods and exhausted out of the building. However, lubricant mist can be observed in the plant during rolling operation resulting in worker exposure to volatile organic compounds. The U.S. Department of Agriculture (USDA) developed two bio-lubricants by thermal modification of soybean oil as potential substitutes for traditional petroleum-based lubricants. Four trials were conducted using two bio-based and two petroleum-based (conventional) rolling lubricants. The objective of the survey was to gather information which will allow the comparison of VOC emissions and exposures between petroleum and bio-lubricants for the aluminum rolling process.

A survey of room concentrations, ventilation rates and process line activities was carried out in the aluminum mill under normal process operation using the bio- and petroleum lubricants. Stack samples were collected following EPA compendium method TO-17, active sampling onto activated carbon sorbent tubes. Hourly concentrations of VOC were determined at 6 different locations at the mill using personal monitoring pumps and charcoal adsorbent tubes. A total of 43 samples were collected during the two day trial. Air samples and bulk lubricant samples were analyzed by gas chromatography with flame ionization detection (GC-FID). The chromatograms from the samples collected during the hot rolling show different patterns than the ones from the bulk lubricant sampling due to a breakdown of the lubricant molecules into straight chain low molecular weight hydrocarbons. This does not occur while sampling for emissions while running the lubricant without hot metal. The highest VOC concentrations where observed, as expected, while rolling. Concentrations where in the range of 200 to 1079 mg/m³ for bio-lubricants. Lower concentrations were observed while sampling with the lubricants running without metal rolling and for the petroleum-lubricants they were in the range of 32 to 110 mg/m³.

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Respirable Dust Exposures Among Portland Cement Workers

Angela Dix, W. Sanderson, University of Iowa, Iowa City, IA.

Exposure to Portland cement dust is reported to lead to a greater prevalence of respiratory symptoms.  However, few studies include information about the dust exposures encountered by Portland cement workers.

Compliance officers of the Mine Safety and Health Administration (MSHA) routinely collect personal dust monitoring samples in every Portland cement plant within the United States.  The dust monitoring includes samples for airborne total and respirable dust and respirable quartz concentrations.  The respirable dust samples were analyzed for quartz content by x-ray diffraction.  These measurements represent the best available exposure surveillance data for these workers.  Exposure compliance data was requested from MSHA via a Freedom of Information Act request.  Data was obtained from thirteen plants in four states: Iowa, Kansas, Missouri, and Nebraska.  The sample data was analyzed by plant, job, and time period to determine significant differences between them. 

Between 1978 and 2005, 1282 dust samples were collected at these 13 plants.  Jobs were broken into seven categories based on tasks and location.  Time period was split into seven four year intervals.  Dust levels differed significantly across plants, jobs within plants and over time.  However, dust levels were not found to decrease significantly over time.  Raw material production jobs had higher concentrations of respirable quartz than did any other job category. 

These dust measurements may not represent the actual dust exposures of all workers within these 13 plants over time.  However, MSHA compliance data is the most comprehensive exposure database available for Portland cement workers.  The data indicate that these workers may sometimes be over exposed to airborne dust, including respirable quartz.  The data may be used to evaluate differences across plants, jobs within plants, over time, and to guide interventions to reduce exposures.

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Comparison of Diesel & BioDiesel Exhaust From School Buses

N. Knapp, W. Sanderson, University of Iowa, Iowa City, IA

The U.S. Environmental Protection Agency (EPA) and the American Lung Association have produced documents recommending that the exposures of children to diesel exhaust be reduced. In particular, EPA has targeted diesel emissions from diesel-powered school buses.  School districts do not have the money to upgrade buses as new diesel engine regulations are implemented.  As alternative diesel fuels become available, it is important that their combustion profiles be evaluated to assure they are a safe substitute to regular diesel fuel.  This project monitored the concentrations of gases and airborne particulate from the exhaust of diesel-powered school buses while they were in the process of loading and unloading children near school buildings.  Four sampling sites with varying fuel sources and engine idle time were compared.  One school district used diesel fuel, while the other used 20% soy-diesel mix.  Data was obtained through real-time and grab samples of ambient air and climatic conditions. 

The samples were analyzed for elemental carbon (EC) and organic carbon (OC) by NIOSH method 5040 and for polycyclic aromatic hydrocarbons (PAH) by GC/MS.  The method detection limit for PAH analysis is typically from 1 ug/l to 5 ug/l.  Due to the short duration of each exposure, results below detection limits were obtained.  Methods for short duration sampling of EC/OC, PAH and nitro-PAH must be refined to determine specific exposures to students, teachers, drivers and the public.  Further research in this area is needed due to the varying age of the buses and the growing diversity of alternative fuels.

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Monitoring Risks in Association With Wastewater Treatment Workers’ Health

J. Lee, P. Thorne, P. O’Shaughnessy, The University of Iowa, Iowa City, IA; S. Reynolds, Colorado State University, Fort Collins, CO; J. Johnson, Lucas State Office Building, Des Moines, IA.

This study aims to investigate job tasks and symptoms in connection with exposure levels of hydrogen sulfide (H₂S) and endotoxin in wastewater treatment facilities.  Ninety-three and forty nine workers participated in a symptom survey and personal monitoring respectively. The job tasks were classified into nine categories, for instance, workstation-inspection, and sludge-delivery. Logistic regression analysis was performed to compute statistical associations, controlling age, gender, smoking, employment-years and asthma. The outcome showed less than 1 ppm of H₂S for all monitored tasks and averaged endotoxin level was 1071 EU/m3.  Among the tasks, workers were exposed to H₂S at high levels during cleaning-workstation (0.8 ppm); however, over 100 ppm maximum levels were detected when in sludge-related locations or performing sludge-transportation. Prevalence rates of surveyed symptoms varied (0~44%) and sinus trouble showed the highest prevalence rate.  12.9% and 36.6% of workers reported having chronic bronchitis and toxic pneumonitis respectively.  The CES-D scales indicated that 48.3% of the workers were depressed.  The workers reported high occurrence rates of symptoms at work (75%) and the symptoms occurred 3.3 days at work on average.  Mucus irritation showed high rates of improvement after work of the day (56~100%) whereas gastrointestinal symptoms had low rates (0~37%).  Several tasks showed statistically significant associations with varied symptoms; workstation-inspection with memory-difficulties (P<0.001), sludge-handing with nasal-irritation and sinus-trouble (P<0.05), and handling-chemicals with stomach-pain, diarrhea, and eye-irritation (P<0.05).  In summary, the symptoms were work-related and associated with particular job tasks.  Plus, limited available health protection devices were noticed in the participating facilities.  Therefore, user-friendly respirators and appropriate administrative controls must be developed and provided.  Suggested administrative controls include education, duty assignment considering workers’ susceptibility to certain symptoms related to the tasks, and a reduction of time spent at the tasks or worksites associated with high risks.

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Effect of Aviation Snip Gripping Technique on Muscle Activity and Wrist Posture

A. Meyers, D. Anton, G. Zamba, The University of Iowa, Iowa City, IA. G

Background:  Musculoskeletal disorders (MSDs) are responsible for billions of dollars in workers’ compensation claims and other costs. Construction workers are particularly at risk for MSDs because of their exposure to physical risk factors. Sheet metal workers’ heavy use of hand tools exposes them to physical risk factors such as awkward wrist posture and forceful exertion. Various tool gripping techniques may be associated with increased exposure to these risk factors. The purpose of this study was to assess the effect of self-selected tool gripping techniques on exposure to physical risk factors while performing a simple cutting task.  Methods:  Subjects cut a circle in sheet metal positioned at shoulder level using standard aviation snips. Muscle activity was measured by surface electromyography (EMG) of three arm muscles and wrist posture was measured by electrogoniometry of the wrist. Two primary tool gripping techniques were observed. For both techniques, subjects made cuts with the thumb on the bottom handle of the snip, but 11 subjects cut with a neutral forearm position and the other 9 cut with a pronated forearm. The independent variable was gripping technique. The dependent variables were: mean normalized RMS EMG data for the three muscles tested and the proportion of time spent in non-neutral wrist postures. Results: Independent t-tests showed that the forearm pronated gripping position used significantly more muscle activity in two of the three muscles tested. Participants who cut with the forearm pronated gripping technique also spent a greater percentage of time in a non-neutral (extended or flexed > 20°) wrist posture. Regression was used to compare the two tool gripping techniques and adjust for the possible influence of grip strength and work experience.

Conclusion: Preliminary findings suggest that more muscle activity and more non-neutral wrist postures were evident with the pronated forearm gripping technique.

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Airborne Antibiotic Exposures in Animal Feeding Operations

M. Murphy, W. Sanderson, J. Vargo, University of Iowa, Iowa City, IA

For over fifty years, antibiotics have been added to livestock feed to reduce disease and promote growth.  This has been a controversial practice however, because overuse of antibiotics leads to resistance in bacteria that may cause disease in humans.  The Centers for Disease Control and Prevention estimate that over 50 million pounds of antibiotics are produced in the U.S. each year and about 40% of that is used for livestock, particularly as feed additives.  The dangers of occupational and environmental exposure to antibiotics and antibiotic-resistant micro-organisms remain largely unknown.

The purpose of this project was to measure the airborne antibiotic exposures in a livestock production facility.  Samples were collected in hog facility which included rooms devoted to farrowing, nursery, and growing operations.  The antibiotic tylosin was mixed within the feed in every room, while lincomycin was not currently included in the feed but had been used in the past.  Analytical methods were developed in collaboration with the University of Iowa Hygienic Laboratory to measure concentrations of tylosin and lincomycin in air samples.  Inhalable (n=34), respirable (n=37), and high-volume (n=16) dust samples were collected in the facility over a two-month period. 

Tylosin concentrations were above the limit of quantitation (LOQ) in 93% of the samples, while lincomycin concentrations were above the LOQ in only 9% of the samples (LOQ=0.04 nanograms).  The average tylosin concentrations were 3, 18, and 49 ng/m³ in the respirable, inhalable, and high-volume samples, respectively.  No occupational or environmental exposure criteria currently exist for antibiotics in air.  The information collected in this study can be used to estimate workers exposures and develop interventions to reduce occupational exposures.

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Pattern Recognition Techniques for VOC Determinations With a Portable GC Equipped With a Tunable Separation Module and a Multi-Sensor Array Detector

Chunguang Jin, E. Zellers, University of Michigan, Ann Arbor, MI.

This work concerns the development of a novel instrument designed for analyzing complex VOC mixtures found in the workplace or general environment. The instrument is a portable GC with a dual-column separation stage and a microsensor array detector.  The array consists of four chemiresistors coated with monolayer-protected Au nanoparticles that provide partially selective responses to vapors partitioning into the coating layers. Endeavors have been made to develop statistical chemometric methods to address critical modeling and data analysis functions needed to guide the development effort. In order to capitalize on the partial or full temporal separations achieved by the separation module prior to vapor presentation to the sensor array, initial computational routines based on principal component regression methodology have been run sequentially in individual retention time windows within a given chromatogram for pattern recognition. Besides these approaches that use the retention time directly as an additional variable in pattern recognition, the peak shape of an eluting vapor in a chromatogram may enhance the capacity for vapor identification. A computation-intensive multi-way analytical technique is now being pursued to exploit all relevant variables affecting vapor classification and identification. A goodness-of-fit method based on the Mahalanobis distance was developed to address the fidelity problem associated with assignments of identities of vapors on the basis of their array response patterns. This led to a robust decision rule for confirming the identity of the unknown vapor at desired confidence level (e.g., 95 or 99%). This decision rule has been tested and performed satisfactorily on two real data sets collected separately from the SAW sensors and from chemiresistor sensors. Correct recognition rate was achieved in 83% of cases for the SAW sensor data set and in 95% of the cases for the chemiresistor sensor data set.

46
Effect of Voltage and Wire Feed Speed on Welding Fume Characteristics

C. Hovde, P. Raynor, University of Minnesota, Minneapolis, MN.

Iron oxide and manganese oxide are the main components of gas metal arc welding fumes.  Excessive inhalation exposure to these compounds can lead to siderosis, a benign form of lung cancer, and manganism, a neurological disorder.  In addition, research suggests that the smaller particles may be more toxic than larger particles.  The goal of this research was to determine if welding fume characteristics change with variables in the welding process that generates them.

Fume characteristics were measured on three separate occasions for all combinations of four voltage levels and three wire-feed speeds for a total of 36 experiments run in random order. A weld apparatus was used to keep the shield gas, travel speed, welding wire, base metal, gun angle, and airflow constant.  Manganese, iron, and total particulate were sampled close to the welding process on mixed cellulose ester membrane filters, which were subsequently analyzed at an accredited industrial hygiene lab.  An ultrafine particle counter measured the particle number concentration.  A handheld optical particle counter measured the particle size distribution.

Submicron particle counts depended on voltage levels but not wire feed speed.  The ultrafine particle counts were doubled from the lowest voltage level to the highest. The 0.5 mm particle counts increased from 10,440 particles/cc at low voltage to 83,880 particles/cc at high voltage.  Manganese, iron and total particulate concentrations also depended on voltage levels but not wire feed speed.  For example, manganese concentration was 1.7 mg/m³ at the lowest voltage versus 6.4 mg/m³ at the highest voltage.

The results suggest that welders are exposed to higher particle mass and number concentrations at higher voltages, potentially leading to higher incidence of welding diseases.  The data also suggest that welders should weld at lower voltage levels whenever possible.  If higher voltages must be used, extra control measures should be considered.

47
An Assessment of Airborne Infectious Isolation Rooms in Minnesota Hospitals

S. Saravia, P. Raynor, A. Streifel, University of Minnesota, Minneapolis, MN.

The goal of this project was to help Minnesota hospitals assess their isolation room capabilities to prepare for airborne infectious disease outbreaks.  A total of 678 airborne infectious isolation rooms were evaluated in 140 Minnesota hospitals.  The pressure differentials between the isolation rooms and adjacent areas were measured for each of the rooms and construction details were recorded.  Ultrafine particle concentrations were measured in the rooms, the surrounding areas, and the ventilation systems that served the rooms.  The information gathered for each room was compared to construction guidelines established by the American Institute of Architects and the Centers for Disease Control and Prevention.

Many of the isolation rooms did not  fit all of the functional criteria.  Isolation rooms with solid ceilings had an average pressure differential of -.019 in. H₂O, which was significantly higher than the average pressure differential of -.008 in. H₂O for those with dropped ceilings (p < 0.0001).  Although more air changes per hour in the isolation rooms was significantly related to the pressure differential (p = 0.02), the air changes per hour only explained a small portion of variance in the pressure differential data (R² = 0.014).  Isolation room ultrafine particle concentrations were more highly correlated with the particle levels in air from surrounding areas (R² = 0.55, p < 0.0001) than with particle levels in the air in the ventilation systems that served those rooms (R²=.16, p = 0.0001). 

The results suggest that hospitals are not all maintaining airborne infectious isolation rooms to correspond with guidelines.  The findings also indicate that having a tightly sealed room helps maintain an appropriate pressure differential.  Further research should be conducted to investigate the amount of air that enters isolation rooms through the undercut of the door and through cracks and perforations.

48
Prediction of Volitional Muscle Fatigue at Low-level Exertions

M. Wan, T. Bernard, University of South Florida, Tampa, FL.

Low-level static exertions in many jobs imply an occupational risk because they are often sustained for prolonged time with insufficient rest allowance. They are believed to be associated with musculoskeletal disorders.

Rohmert’s equation reported in 1960 relates endurance time to effort, represented by the muscle’s percentage of maximum voluntary contraction (%MVC). It implies that holding may extend indefinitely for efforts below 15% MVC. Subsequent studies show that this percentage overestimates the endurance limit.

This study explored the relationship between endurance time and %MVC of elbow flexion. The null hypothesis was that there was no difference between Rohmert’s equation and the relationship between endurance time and %MVC in low-level exertions. A secondary aim was to determine whether 15% MVC should be considered an acceptable level of exertion for an indefinite holding time.

Four men and six women 19-36 years of age participated. We used a standard protocol for static strength testing to measure MVC for each participant and computed the target torques for the submaximal trials. At the lowest experimental level of 5% MVC, nine out of 10 subjects exhibited endurance times between 10 and 44 minutes, where according to Rohmert’s prediction, the endurance time should be indefinite. The differences between the endurance times from the study data and from Rohmert’s equation were statistically significant at 5%, 10%, and 15% MVC. 

Rohmert’s equation significantly underestimates the endurance times for low-level static exertions below 15% MVC. A new model was derived from the study data, incorporating sex difference as a predictor variable in addition to %MVC. It can be used as a conservative, safe, and practical tool for the design of jobs that require prolonged periods of low-level static work involving elbow flexion.

49
Comparison of Indoor and Outdoor PM 2.5 Measurements at a Utah Elementary School

D. Nye, R. Larson: University of Utah, Salt Lake City, UT; R. Dalley, B. Allen: Utah Air Monitoring Center, West Valley City, UT; G. Smith,  Salt Lake City School District, Salt Lake City, UT.

Along the Utah Wasatch front in winter conditions, air quality often becomes problematic for the young and infirm.  Strong temperature inversions cause outdoor urban pollutants levels such as Particulate Matter 2.5 (PM 2.5) to rise to unacceptable levels.  Studies have shown that high PM 2.5 levels can be an asthma trigger for youth. The goal of this project was to determine that guidance given to schools, such as that in the United States Environmental Protection Agency’s  (EPA)“Tools for Schools” indoor air quality program is justified.  In this study, PM 2.5 was measured in a Utah Elementary School using a tapered element oscillating microbalance (TEOM) located in the library of the school.  Indoor measurements during poor outdoor air quality days were compared to measurements collected by a similar TEOM in an EPA air-monitoring station already in place on the school property.  In addition, on select days, a filter method (MiniVol) was also used to collect indoor PM 2.5 levels.  Indoor to Outdoor ratios (I/O) were not statistically different from 1.0 with a 95% confidence interval of [0.53, 1.27] (n=55).  However, indoor PM 2.5 was significantly lower than outdoor PM 2.5 (p<0.0001, n=55).  Results of the study indicate that indoor PM 2.5 levels during temperature inversions are indeed lower than outdoor levels.

50
The Effect of Ethanol Consumption on the Rate of Biotransformation of 1,1,1-Trichloroethane

D. Johns, M. Morgan, W. Daniell, D. Kalman, D. Shen, University of Washington, Seattle, WA

There are many environmental factors that affect the toxicokinetics of organic solvents in the body.  These include diet, physical activity, smoking, drinking habits, and co-exposures to other solvents.  In the workplace, this variability in toxicokinetics can influence both biological monitoring results, and more importantly, the health of the worker.  Ethanol consumption is likely one of the most important factors affecting the toxicokinetics of solvents because it is often consumed in multi-gram quantities.  Ethanol oxidation is catalyzed in part by the same enzyme (CYP450 2E1) that mediates the metabolism of many organic solvents. 

This study evaluated the effect of moderate doses of ethanol over a short period of time on the biotransformation of an organic solvent, 1,1,1-trichloroethane.  A group of ten moderate drinkers were recruited and exposed via inhalation for two hours to a low concentration of 1,1,1-trichloroethane (175 ppm) on two separate occasions.  Subjects were administered moderate doses of ethanol on each of the seven days preceding one of the exposures.  Prior to the other exposure, subjects were given no ethanol and were asked to abstain from ethanol consumption for a two week period.  Total urine was collected f