M. Harper, B. Pacolay, NIOSH, Morgantown, WV; P. Hintz, M. Andrew, NIOSH, Spokane, WA.
Recycling operations allow for the recovery of lead from used lead-acid batteries that can then be sold back to battery manufacturers to form a closed loop, significantly reducing environmental contamination. Personal samples were taken for analysis for the principal airborne metal, which is lead, although several other metals were present including antimony, tin, and copper. Samplers used in this study included the closed-face, 37-mm filter cassette (the current U.S. standard method for lead sampling), the 37-mm GSP or “cone” sampler, the 25-mm Institute of Occupational Medicine inhalable sampler, the 25-mm button sampler, and the open-face, 25-mm cassette. The mixed cellulose-ester filters from these samplers were analyzed after sampling for their content of various metals, particularly lead, using a portable X-ray fluorescence (XRF) analyzer, and then were extracted with acid and analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The 25-mm filters were analyzed using a single XRF reading, whereas three readings on different parts of the filter were taken from the 37-mm filters. For lead, all five samplers gave good correlations (r2 > 0.92) between the two analytical methods over a very wide range above the permissible exposure limit enforced by OSHA. Linear regression on the results from most samplers gave almost 1:1 correlations without additional correction, indicating an absence of matrix effects from the presence of other metals in the samples. Even though very high concentrations of lead were encountered (up to almost 6 mg/m3) no saturation of the detector was observed. A negative bias was found for the slope of the button sampler regression. All samplers performed well, with > 90% of XRF results within ±25% of the corresponding ICP results for the optimum configurations. The OSHA algorithm for the CFC worked best without including the backup pad with the filter.
M. McCullough, E. Gross, Dana-Farber Cancer Institute, Boston, MA.
Increased use of animal in vivo imaging equipment, like the Xenogen IVIS imaging system, has increased the possibility of overexposure to halogenated anesthesia for animal workers and researchers. The Xenogen and other in vivo animal imaging systems do not come fitted with integrated anesthesia delivery equipment. To determine whether staff were being exposed to excessive levels of isoflurane, we conducted air sampling on personnel using an imaging system both with and without the nonstandard anesthesia equipment. We also wanted to determine if there were other, less expensive methods of control. During the process, we were able to determine the pathways of exposure and eliminate or control them to acceptable levels. Sampling results indicated that the accessory equipment is necessary and that a program to maintain compliance is also required.
M. Eide, U.S.DOL/OSHA, Sandy, UT.
OSHA desired a validated method for formaldehyde using a diffusive sampler that could be used for collecting STEL and TWA samples. Diffusive samplers are convenient for the industrial hygienist as there is no sampling pump to calibrate and carry to the work site. Diffusive samplers are less obstructive for the worker as there is less equipment to wear. The OSHA’s earlier method, OSHA ID205, using a 3M 3551 badge, could not be used for STEL sampling. The performance of three different diffusive samplers was examined with the use of OSHA’s Evaluation Guidelines for Air Sampling Methods Utilizing Chromatographic Analysis. The three samplers used were: for Assay Technology ChemDisk 571 Aldehyde Monitors, SKC UMEx 100 Passive Samplers, and Supelco DSD-DNPH Passive Sampler. These three samplers use 2,4-dinitrophenyl hydrazine chemistry to produce a stable formaldehyde derivative and to have adequate sensitivity to monitor both TWA and STEL samples. Samples are analyzed by LC with a UV-vis detector. There are limitations on the use of these samplers based on the source of the formaldehyde exposures, ozone concentration, humidity, and workplace environment. These limitations were similar for all three samplers. If these limitations are taken into consideration, these diffusive samplers provide a useful means of monitoring workplace exposure to formaldehyde.
W. Xu, S. Que Hee, UCLA, Los Angeles, CA.
Metalworking fluids (MWFs) are widely used for metal machining and have caused skin disorders, respiratory symptoms, and concerns about carcinogenicity. The complexity of MWFs handicaps the analysis of their components. The aim of this study was to identify and quantify an unknown peak in the chromatogram of a straight oil MWF. The fraction that permeated a thin nitrile polymer membrane had less mineral oil background than did the original MWF, thus facilitating identification by total ion current gas chromatography/mass spectrometry (GC/MS). The peak proved to be di-n-octyl disulfide (DOD) through retention time and mass spectral comparisons. Quantitation of DOD was by extracted ion chromatogram analysis of the DOD molecular ion (mass-to-charge ratio (m/z) 290), and of m/z 71 ion for the internal standard, n-triacontane. Classical linear models of the area ratio (y) of these two ions vs. DOD concentration showed a systematic negative bias at low concentrations, a common occurrence in analysis. Computation with statistical software provided the optimal Box-Cox power transformation value of 0.8. The new linear model of y0.8 versus DOD concentration showed negligible bias from the lowest measured standard of 1.51 mg/L to the highest concentration tested at 75.5 mg/L. The intercept did not differ statistically from zero. The concentration of DOD in the MWF was calculated through Box-Cox transformation to be 0.398 ± 0.034% (w/w) by the internal standard method, and 0.387 ± 0.036% (w/w) by the method of standard additions. These two results were not significantly different at p ≤ 0.05. The Box-Cox transformation procedure is therefore recommended for industrial hygiene and environmental measurements and analyses when the data for standards are nonlinear.
C. Glowacki, Technikon, Dublin, OH.
This report describes the results of source testing conducted at the General Motors Saginaw Metal Casting Operations, Saginaw, Michigan. The purpose of the testing was to evaluate the bias and repeatability of five different methods or method variations for the determination of styrene emissions from a lost foam foundry operation. A range of concentrations was evaluated by collecting samples at the inlet and outlet of two regenerative catalytic oxidizers. Three test teams were involved in the sampling and all samples were collected simultaneously. The methods evaluated included US-EPA Method 25A standardized with propane or styrene, US-EPA Method 18 sorbent tube version using both charcoal and Carbopak tubes, and USEPA Method 18 Tedlar bag version. Charcoal tube samples were collected by two of the test teams using different sampling equipment. The charcoal tubes were then solvent recovered by two different laboratories. In addition, duplicate charcoal tube samples collected by the test teams were split between the laboratories. The Carbopak tubes were thermally recovered by one laboratory. Finally, the results from the THC standardized with propane were adjusted for the response difference between propane and styrene so that the data could be compared on a styrene basis. The data clearly shows that samples on a prototype sorbent tube sampling device and subsequently solvent recovered provided the most accurate estimation of the true value for styrene. Surprisingly, the Method 25A results, whether standardized with styrene or response corrected, were superior to the other Method 18 versions. Advantages and weaknesses of the various sampling and analytical techniques will be discussed.
Z. Jurjevic, EMSL Analytical, Inc., Westmont, NJ; G. Rains, D. Wilson, M. Tertuliano, University of Georgia, Tifton, GA; J. Tomberlin, Texas A&M University, Stephenville, TX; W. Lewis, USDA, Tifton, GA.
Aflatoxigenic and nontoxigenic Aspergillus flavus strains were grown on corn, peanut, and potato dextrose agar to determine differences in the production of mcrobial volatile organic compounds (MVOCs) on these different substrates. Relating specific MVOCs to specific fungi can be an indicator of early fungal activity in water damaged homes and possible mycotoxin production. MVOCs were collected by trapping headspace volatiles using thermal desorption tubes packed with Tenax TA and Carbotrap B. Samples were collected in various fungal growth stages and aeration. Trapped compounds were thermally desorbed from the adsorbent tubes, separated by gas chromatography, and identified by mass spectrometry. The fungal growth stage did not have many differences in the fungal volatile spectra,but the intensity of some volatiles changed over time. Volatiles that were associated with both A. flavus strains on all three substrates included: ethanol, isopropyl alcohol, 1-propanol, butanal, 2-methyl-1-propanol, 3-methylfuran, ethyl acetate, 1-butanol, 3-methylbutanal, 3-methyl-1-butanol, propanoic acid-2-methyl-ethyl-ester, 2-methyl-1-butanol, 1-pentanol, 2-pentanol, 3-methyl-3-buten-1-ol, benzaldehyde, 3-octanone, 2-ethyl-1-hexanol, and octane. Volatiles that were associated only with the aflatoxigenic A. flavus strains included: ethylbenzene, dimethyl disulfide, and nonanal. Volatiles that were associated with A. flavus nontoxigenic included: hexanal, 1-hexanol, 1-octene-3-ol, 1-octen-3-one, 2-pentyl furan, and octanol.
J. Warburton, I. Christie, T. Baker, T. Cowburn, City Technology Ltd., Portsmouth, England.
Airborne enzymes can present a potential health risk to workers in many industries. The detergent industry has minimized worker exposure by containment and monitoring programs. There is a need for a personal monitoring system, especially if sensitive enough to give a measure of exposure to localized peaks of higher exposure associated with particular tasks or events. An easy to use cartridge has been developed for personal monitoring of exposure to subtilisin, containing collection filter, reagents and a chamber in which the reaction takes place. During sampling it is worn in a holster on the lapel where air is drawn through the filter by a standard pump. The cartridge is removed placed in a reader instrument in which the amount of captured enzyme is determined by an optical measurement. The capture filter remains in the cartridge at all times, being stored in a protected region to prevent contamination or loss of captured material. Filter movement within the cartridge and release of reagents may be automatically actuated by the instrument. No separate extraction or filtering is required, avoiding loss of enzyme. Analysis takes 15 minutes. Results show linear calibration up to at least 40 ng enzyme and a detection limit of less than 1 ng. This is adequate for monitoring low levels over a shift or detection high peak exposures of shorter duration. As no sample preparation is involved, the system was challenged with a range of potentially interfering particulates. Detergent powder did not cause errors either as background turbidity in the reaction or from the presence of dust on the outer surface of the cartridge, nor did cigarette smoke or diesel vehicle exhaust. It is envisaged that the system could be adapted for use with other enzymes, such as amylase or lipase, and in other industries, such as baking.
A. Panepinto, M. Emley, R. Hunt, P&G, Cincinnati, OH; I. Christie, City Technology Ltd., Portsmouth, United Kingdom.
Historically, the industrial hygienist in the manufacture of detergents containing proteolytic enzymes has had to rely on high-volume, nonparticle, size-selective techniques for air sampling. This difficulty can be linked to enzymes having very low occupational exposure guidelines, as well as limitations in the sensitivity of analytical methods. Exposure assessment has also been difficult due to lack of availability of size-selective samplers that operate in a high-volume airflow regimes. This has necessitated the use of area sampling techniques that do not permit an assessment of the exposure profile for an individual worker.
This study evaluated the performance of a personal enzyme sampling system developed by City Technology. This sampling system utilizes a cartridge that contains an inhalable sampling head, a collection filter, reagents, and a reaction chamber suitable for monitoring airborne subtilisin protease. Following the sampling period, the cartridge is then placed into a reader that moves the filter into the reaction chamber and releases the reagents. The amount of captured enzyme is determined by an optical measurement, with the analysis taking 15 minutes. This study evaluated the suitability of this system for monitoring of low exposures as well as peak exposures of shorter duration. Controlled test atmospheres of liquid detergents were generated in a 9 m3 chamber at concentrations of 5, 15, 30, and 60 ng/m3 of protease protein through atomization. The sampling durations were varied between 15 and 180 minutes. Test atmosphere were validated through use of high volume samplers coupled with enzyme analysis by the traditional ELISA technique. The results of these tests provided good correlation between cartridge responses and the content of sampled air. The calibration of this monitoring system was linear over the range of concentrations evaluated in this study with a limit of detection of 0.5 ng of protease protein.
Posted May 30, 2006