R. Neitzel, M. Paulsen, C. Simpson, University of Washington, Seattle, WA; L. Naeher, University of Georgia, Athens, GA; K. Dunn, A. Stock, D. Barr, Centers for Disease Control and Prevention, Atlanta, GA.
Urinary methoxyphenols have been proposed as biomarkers of wood-smoke exposure. However, few field studies have been undertaken to evaluate the relationship between wood-smoke exposure and urinary methoxyphenol concentrations. We conducted a pilot study in which carbon monoxide (CO), levoglucosan (LG), and particulate matter (PM2.5) exposures were measured in wildland firefighters on burn days. Pre- and post-shift urine samples were collected from each subject, and cross-shift changes in creatinine-corrected urinary methoxyphenol concentrations were calculated. Correlations between exposure measures and creatine-adjusted urinary methoxyphenol concentrations were explored, and regression models were developed, relating changes in urinary methoxyphenol concentrations to measured exposure levels.
Full-shift measurements were made on 13 firefighters over 20 work shifts in winter 2004 at the U.S. Forest Service Savannah River, a national environmental research park. LG and PM2.5 measurements on the personal filter samples from the firefighters were significantly correlated. LG and CO exposures were significantly correlated for samples that represented at least 60% of the work shift (16 samples) but not for the smaller set of full-shift exposure samples (n=9). PM2.5 and CO exposures were only significantly correlated when all available measures, including those representing less than 60% of the workshift duration, were considered. Significant cross-shift increases were observed in the creatinine-adjusted concentrations of 14 of the 22 methoxyphenols evaluated. Individual and summed creatinine-adjusted guaiacol urinary methoxyphenols were highly associated with CO (and, to a lesser degree, LG) exposure levels, and regression models including CO and LG exposure levels explained up to 79% of the variance in cross-shift changes in summed creatinine-adjusted guaiacol urinary methoxyphenol concentrations. Although limited by the small sample size, this pilot study demonstrates that urinary methoxyphenol concentrations may be effective biomarkers of occupational exposure to wood smoke among wildland firefighters.
K. Czarnocki, E. Czarnocka, T. Baum, Lublin University of Technology, Lublin, Poland.
The objective of the study is to assess the external and internal exposures to aromatic hydrocarbons in the cistern cleaning and cistern mechanic repair processes at a coke plant. One hundred and fifty-seven workers engaged as operators in cistern cleaning and cistern mechanic repair processes as well as 35 nonexposed subjects were examined. Personal analyses of the benzene, toluene, xylene isomers, ethylbenzene, PAHs, and aldehydes in the breathing zone air allowed us to determine the time-weighted average (TWA) exposure levels to the aromatic hydrocarbons listed above. The internal exposure to benzene was investigated by measurement of the urinary excretion of S-phenylmercapturic acid (SPMA) by means of high-pressure liquid chromatography (HPLC). Time of workers exposure to chemicals, work energetic cost, and dietary customs of workers (including smoking and consumption of alcoholic beverages) were monitored during the experiment. The TWA concentrations of the hydrocarbons detected in the breathing zone air shows that the exposure levels of the workers are relatively high in comparison to the exposure limits. Statistically significant correlations of SPMA concentration in urine and benzene concentration in the breathing zone air (Pearson r= 0,849, n= 151, p<0,001) determined at the workplaces in the cistern cleaning department and cistern mechanic repair department have been found. Concentrations of the benzene, toluene, and ethylbenzene detected in workers from the cistern mechanical repair department are higher that those from the cistern cleaning department. Concentrations of trans,trans-muconic acid (tt-Ma) in the urine of occupationally exposed workers were significantly higher than those of nonexposed subjects. Concentrations of SPMA in urine were significantly higher for the cistern cleaning workers. Operators at the cistern cleaning and cistern mechanical repair processes are simultaneously exposed to a mixture of different hydrocarbons and aldehydes.
O. Kampa, ConocoPhillips, Bartlesville, OK; Industrial Hygiene Task Force, American Petroleum Institute, Washington, DC.
OSHAs hexavalent chromium (Cr+6) standard requires employers to perform an exposure determination on all work activities that may involve exposure to Cr+6. To streamline this effort for their member companies, the American Petroleum Institute funded a project that collected objective data on seven types of hot work including carbon arc cutting (CAC), flux cored arc welding (FCAW), gas metal arc welding (GMAW or MIG), grinding, gas tungsten arc welding (GTAW or TIG), oxyfuel gas cutting (OFC or torch cutting), and shielded metal arc welding (SMAW or stick). Personal samples were collected during the cool season (October-November 2005) and warmer weather (April-June 2006) at five maintenance turnarounds and new construction projects. A total of 271 full-shift samples was collected. Sixty-three or 23% of the full-shift samples were at or above the OSHA action level of 2.5 µg/m3. Fifty-one or 19% were at or above the OSHA permissible exposure limit (PEL) of 5 µg/m3. Worker exposures were characterized based on hot work activity, base metal, and work environment. Results indicate that the following hot work activities will likely be below the PEL: open-air FCAW on stainless steel and open air grinding on all metals except stainless steel. The following welding operations will likely be above the PEL: confined space CAC on chrome steel and stainless steel, confined space GMAW on carbon steel, and confined space SMAW on stainless steel.
S. Tsai, Institute of Environmental Health, National Taiwan University, Taipei, Taiwan; M. Huang, Department of Occupational Safety and Health, China Medical University, Taichung, Taiwan.
Furfural is a widely used industrial chemical. Furfural can also be found in numerous processed foods and beverages. Exposure by ingestion is possible, but inhalation and dermal exposures of furfural are also possible. The OSHA permissible exposure limit (PEL) of furfural bears a skin notation. On the other hand, biological monitoring of furfural by the analysis of furoic acid in urine is recommended by ACGIH. Therefore a rapid, cost-effective, and accurate sampling and analysis method of furoic acid in urine would be of extreme benefit for the exposure assessment of furfural. The aim of this research was to develop a simple solid-phase microextraction (SPME) procedure for the determination of creatinine and furoic acid in urine. For furoic acid, the poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB) fiber was used with a direct urine sample immersed for 60 sec under 1200 rpm magnetic stirring followed by the analysis with gas chromatography-mass spectrometry (GC-MS). For the analysis of creatinine, the PDMS/DVB fiber was also first directly immersed into the urine sample for 60 sec under 1200 rpm magnetic stirring. Then the fiber was transferred to a 4 mL vial that was filled with 100 μL of trifluoroacetic anhydride (TFAA) and stood 30 sec for headspace extraction. Afterward the fiber was transferred again to another blank 4 mL vial and stood 10 min for on-fiber derivatization before the analysis with GC/MS. The absorption-time profiles for both furoic acid and creatinine were examined. The relative standard deviations of the analysis were found to be less than 10%, and the accuracy was 100±10% for both furoic acid and creatinine. With 2 mL of urine sample, MDLs were 0.0077 and 0.13 g L-1 for furoic acid and creatinine, respectively. Compared with other techniques, the study shown here provided a simple, fast, and reliable method for the analysis of furoic acid and creatinine in urine.
W. Shen, Delta Consultants, Troy, NY.
Routine health examinations revealed unexpectedly high numbers of liver function abnormalities among workers in an epoxy laminate manufacturing facility where N,N-dimethylformamide (DMF) was used as one of the primary solvents. Although past air monitoring results indicated insignificant airborne DMF exposure in the production area, a causal link between DMF exposure and liver function abnormalities was suspected on the basis of DMF being known to cause hepatic damage. Subsequently, DMF exposure was evaluated by conducting biological exposure monitoring. During the monitoring, selected employees provided urine samples at the end of their work shifts, and the samples were tested for N-methylformamide (a determinant for DMF). After the initial urine tests indicated potentially high DMF exposure (urine test results ranging 12 mg/l to 68 mg/l N-methylformamide), biological exposure monitoring was expanded to include all production employees. In addition, airborne DMF concentrations were measured to identify possible exposure through inhalation. Two rounds of testing of 46 employees in two consecutive months indicated that a majority (38 and 34) of the production employees had n-methylformamide in their urine at levels exceeding the ACGIH BEI of 15 mg/L and half of them exceeded 30 mg/l. Air testing conducted using Draeger-Tubes showed low (negligible) airborne DMF in the common production area. In response to these findings, a thorough review of the facility operation practices was conducted and concluded that dermal exposure was the primary route for DMF exposure. A DMF exposure control program emphasizing reduced skin contact as well as training, biological exposure monitoring, and medical surveillance was established at the facility.
Y. Huang, National Kaohsiung First University of Science and Technology, Kaohsiung, Taiwan; H. Chang, S. Wang, National Cheng-Kung University, Tainan, Taiwan; T. Shih, Institute of Occupational Safety and Health, Council of Labor, Taipei, Taiwan; P. Wang, National Central University, Chungli, Taiwan.
Time-weighted average (TWA) measurements of occupational exposures are often compared with biomonitoring outcomes, but the correlation may not always be significant. In some cases, TWA alone may not be adequate in characterizing occupational exposures. This study examines whether and how intermittent and variable occupational exposures might affect biomonitoring outcomes. For a test case study, workers in a wet process of a synthetic leather plant were recruited. The only chemical hazard in this process is N,N-dimethylformamide (DMF). For each observation, a continuous measurement sensor was used to monitor the variability of airborne DMF concentrations. In addition, a passive sampler was used for a breathing zone TWA estimate, and a real-time monitor was used to measure concentration changes at the main working areas. Finally, post-shift urine samples were collected to analyze the urinary metabolite of DMF (N-formyldimethylamine [NMF]). All of the TWA measurements suggested a low daily exposure level; however, urinary NMF concentrations varied substantially among workers and could not be properly explained by TWA concentrations alone. Records from the sensor showed intermittent exposures to the vapor. The varying and intermittent exposure levels were taken into consideration in a physiologically based pharmacokinetic (PBPK) model, which was set to predict biomarker levels by respiratory exposure level. The modeling parameters were calibrated with previous field measurements, and exposure concentrations were estimated by work segment according to the sensor records and on-site measurements. The predicted urinary biomarker (N-methylformamide) levels closely followed the observed values (r2 > 0.9). In contrast, predictions with TWA estimates yielded less accurate estimates of biomarker levels. Incorporating exposure variability allowed a better explanation between exposure and biomonitoring outcomes.
S. Ghittori, FSM, Pavia, Italy; M. Ferrari, FSM, U.O. Medicina Ambientale e Medicina Occupazionale, Pavia, Italy; M. Imbriani, Universitą degli Studi di Pavia, Pavia, Italy.
A sensitive and rapid method for the determination of toluene in saliva is described. Biomonitoring of toluene exposure is commonly performed by determination of urinary hippuric acid, o-cresol, or toluene itself. The analysis of blood toluene has been verified as another method for biomonitoring. However, blood withdrawals are invasive and often cannot be taken at the workplace for reasons of hygiene. Sampling of saliva is noninvasive and easy to perform, even at the workplace. We studied a group of 40 workers exposed to toluene in the synthetic leathers industry, and 10 nonexposed workers as a control group, to measure the solvent concentration in saliva specimens as an alternative method for biomonitoring. Saliva was collected into Salivette devices by sterile cotton rolls put into the mouth and further squeezed into preweighted vials. Environmental toluene was collected for a work shift by Radiello passive samplers. Toluene in urine and in saliva (headspace analysis) as well as in environmental samples was measured by gas chromatography-mass spectrometry. Environmental toluene levels ranged from 0.22 to 57.20 mg/m3, while the concentrations of the solvent in saliva and urine ranged from 0.56 to 18.30 µg/L and from 0.56 to 26.54 µg/L, respectively. The correlation coefficients (r) of biological measurements for environmental toluene levels were 0.52 and 0.88 for saliva and urine samples, respectively. This preliminary application suggests that saliva may show many advantages over classical biological fluids for example, being more accessible and collectible than blood may be. Therefore, salivary toluene could be considered as one of the possible biomarkers of exposure to toluene.
P. Kalliokoski, M. Veteli, University of Kuopio, Kuopio, Finland; M. Linnainmaa, S. Metsärinne, M. Mäkinen, J. Kangas, Finnish Institute of Occupational Health, Kuopio, Finland; J. Säntti, Finnish Institute of Occupational Health, Helsinki, Finland.
Nasal lavage sampling, which has been found useful for assessing occupational exposure to rock and glass-wool fibers in prefabricated house factories, was applied to refractory ceramic fibers in two steel plants, three foundries, and a repair shop. During sampling, each nostril was washed with sterile saline solution. After dissolving the mucus by enzymatic treatment, the samples were filtrated through cellulose ester membrane filters and made transparent with acetone vapor. The fibers were counted with a phase contrast polarized light microscope. A total of 41 samples were analyzed. The mean concentration of fibers varied from 34 to 930 f/mL in the steel plants during the normal production tasks. Neither the use of a respirator nor a specific type of respirator had any clear effect on the concentration. The concentrations were clearly higher, up to 6680 f/mL, in the service shop and during the service breaks in the steel plants when oven insulations were changed, even though respirators were generally worn. The concentrations were generally low in the foundries, where the workers did not wear respirators. At the group level, the nasal lavage values followed the airborne fiber concentrations. However, the correlation was not good at the individual level, where the effect of respirator use was not clear. Although nasal lavage sampling has inherent problems, such as the possibility for fiber accumulation in the nostrils and removal of fibers while blowing the nose during the working day, the inconsistency is probably due to incorrect use and maintenance of respirators. The respirators were often taken off too early while the employee remained in the contaminated area. Poor cleaning of reusable respirators was also possible. In summary, strict surveillance of the selection, use, and maintenance of respirators is crucially important for the success of exposure control.