American Industrial Hygiene Association journal最新文献

This article describes the results of a pilot study to examine changes in the biological component of metalworking fluids (MWF) as a function of use. Fluid samples were taken from two newly charged systems, designated BT-7415 and BT-7707, at 1-week intervals for 8 weeks and characterized with respect to the kinds and numbers of bacteria present and presence of soluble protein in cell-free supernatants. In addition, lipid extracts of pelleted cells from fluids in BT-7415 were examined by gas chromatography/mass spectroscopy for the kinds and relative amounts of phospholipid fatty acids (PLFA) present. A total of 19 different bacterial species was cultured and identified, more than half (12/19) of which were gram-negative. Total colony-forming units (CFU) reached levels of 2.2 x 10(3)/mL in BT-7415 and 2.4 x 10(5)/mL in BT-7707. The most common genus isolated was Pseudomonas. Estimations of cell numbers based on total biomass from PLFA in samples from BT-7415 indicated 1.1 x 10(7)/mL after 8 weeks of use. Both the numbers of PLFA identified and the amounts of each detected in BT-7415 increased as the fluids were used. The chromatograms were dominated by two fatty acids, the amounts of which increased with time. These fatty acids, 18:2 omega 6 and 18:1 omega 9c, are not commonly associated with pseudomonads. This suggests that there is an important component of the biological consortium in MWF is not being detected by currently used culture techniques. There was no soluble protein detected in any of the samples from either system.

Chemical protective clothing (PC) use while working results in elevated rectal temperatures (Tre) that limit work time. Particle barrier, vapor permeable (PBVP) PCs allow workers to cool themselves by evaporating some sweat. The purpose of this study was to compare the effects on worker productivity of two types of PBVP suits, a Kleenguard (PPPC) (Kimberly Clark), and a Tyvek (PEPC) (DuPont) suit. Fifteen males in a repeated measures design performed four work tests consisting of a walk/arm curl combination at a time-weighted work rate of 1.0 L/min (300 kcal/hr), two in a wet bulb globe temperature (WBGT) of 26 degrees C and two in a WBGT of 18 degrees C, with subjects wearing each suit once in each environment. No significant difference (p > 0.05) was observed between the suits at 18 degrees C WBGT, but a significant difference was found (p < 0.05) between the suits, with the PPPC having a lower Tre in the WBGT = 26 degrees C at the 80th, 100th, and 120th min. A significant difference (p < .05) was also seen in the 26 degrees C WBGT with the PPPC resulting in a lower heart rate (HR) at the 40th, 60th, 80th, 100th, and 120th min and rate of perceived exertion (RPE) at the 75th, 90th, and 120th min. Additionally, a significant difference (p < .05) was seen between PEPC and PPPC for Tre, delta Tre, mean skin temp (mTsk), delta mTsk, and HR, each regressed against time in the 26 degrees C WBGT. Twelve of the 15 subjects also reported feeling cooler in the PPPC versus the PEPC in either WBGT environment.

Respirator inspiratory resistance can affect performance times, especially when the experiment is optimized to elicit respiratory stress. Twelve subjects performed on a treadmill at constant speeds and grades chosen to result in performance times of 5-15 min. Six levels of inspiratory resistance were used, ranging from 0.78 to 7.64 cm H2O.sec/L. The results showed that performance times decrease linearly with resistance level, and no threshold resistance value is apparent. Inspiratory resistance also induces hypoventilation, with lower minute volumes and lower oxygen consumption values at higher resistances. These trends are also linear. From these results, there is no value for inspiratory resistance that can be given as a design goal. Other parameters such as weight and space may dictate filter resistance values, and these, in turn, will lead to determined performance degradations.

Industrial respirators offer protection for men and women who are required to work in toxic and oxygen-deficient environments. Major advances continue to be made with respect to improved face mask designs and modes of protection, yet only recently have efforts been directed toward the development of criteria for use in evaluating individuals' psychological fitness to wear respirators. The purpose of the present investigation was to confirm (i.e., replicate) an earlier finding, using a simplified protocol, that an individual's tendency to experience respiratory distress during exercise can be predicted. In the present experiment, an independent sample of 38 subjects underwent a maximal exercise test. It was predicted that subjects with elevated trait anxiety scores would experience respiratory distress when required to perform heavy physical exercise using a full-facepiece, air-line supplied, pressure-demand respirator. The prediction of respiratory distress was accurate in 34 of 38 cases (89.5%). It was concluded that an objective measure of trait anxiety can be used to identify those individuals who are most likely to experience distress while performing maximal physical exercise and using a pressure-demand respirator.

The MIE Miniram PDM-3 is a real-time aerosol dust monitor designed to measure dust based on Mie scattering. It has an optional in-line filter that, when attached to a constant flow air sampling pump, allows a gravimetric air sample to be collected from the same air stream that passes through the Miniram sensing chamber. This study compared real-time Miniram digital respirable and total dust readings with concentrations from an in-line 5 microns polyvinyl chloride filter connected to a constant flow pump and with results from traditional respirable and total dust samples. Area samples were collected at three coal-fired power generating facilities over a 2-month period. Traditional respirable dust concentrations ranged from 0.04 to 10.8 mg/m3. In the monitored range of concentrations the Miniram respirable concentrations and the in-line respirable dust concentrations were not significantly different (p > or = 0.05), nor were the Miniram in-line filter concentrations and the side-by-side respirable dust concentrations significantly different (p > or = 0.05). However, the Miniram respirable concentrations and the traditional respirable concentrations were significantly different (p = 0.02). The Statistical Analysis System (SAS) procedure CALIS, which meets the statistical requirements for developing calibration lines for two variables each measured with error, is used to develop field calibration curves for the comparisons between direct-reading instrument concentrations and concentrations from traditional National Institute for Occupational Safety and Health methods for total and respirable dust.

Blood concentrations of chloroform were monitored after exposing small areas (approximately 5.5 cm2) of the backs of hairless rats to liberal excesses of the solvent for either 1, 3, or 8 min. The amounts absorbed were quantified by comparing areas-under-the-curves (AUCs) of blood concentration versus time plots to the AUC obtained on infusing an aqueous chloroform solution of known concentration for 30 min (positive control). Chloroform penetrated the dermal barrier rapidly, the skin's horny layer and the deeper skin tissues acting as reservoirs for chloroform only for short durations. Evaporative and physiological clearance from these reservoirs was rapid once the chloroform was removed from the surface. Pressure of the template used to confine the exposure affected uptake. For blood levels, the time to reach the maximum blood concentration increased with increased exposure duration. Amounts absorbed also depended on exposure duration. Blood level profiles indicated systemic uptake of chloroform following a 3-min exposure was about 1.3-fold higher than for a 1-min exposure (not significant), while the 8-min exposure produced an AUC roughly 3.8-fold higher than found at 3 min (p = 0.026). Chloroform is rapidly cleared from rat blood (terminal elimination rate constant = 0.009/min). Calculations indicated that its absorption from these area-limited exposures far exceeds that which would be absorbed had the chloroform been presented to the skin as a saturated aqueous solution.

Tank truck drivers' exposure to gasoline vapors was studied by collecting breathing zone samples during loading and unloading of gasoline. The field studies were conducted at three dispatches and at seven service stations in Finland. The gasolines included in the study (95, 98, 99 research octane number, RON) were of reformulated or oxygenated grade containing about 2% (w/w) oxygen and 0.5-1.5% (v/v) benzene. The sampling times ranged from 16 to 57 min (mean 35 min), and time-weighted average concentrations for a 30-min period were calculated. Using the time-adjusted values, geometric mean concentrations (GM) were calculated for three periods of dispatch measurements (n = 15,20,7) and a period of unloading measurements at service stations (n = 7). The GM for methyl tert-butyl ether ranged from 0.95 to 7.3 mg/m3 and that for tert-amyl methyl ether from 0.30 to 1.1 mg/m3. The GM concentrations of hexane, benzene, and toluene were in the range of 0.25-2.3 mg/m3, 0.15-0.28 mg/m3, and 0.73-1.7 mg/m3, respectively. Multiple regression analysis yielded an r2 value of 0.98 for the daily mean concentration of toluene and correspondingly 0.94 for benzene when daily wind speed (0.1-3.7 m/sec) and daily air temperature (-7.4(-)+17.2 degrees C) were used as independent variables. The average number of gasoline loads per tank truck was 2.5, corresponding to 23,000 L of gasoline.

The U.S. Environmental Protection Agency and the U.S. Department of Housing and Urban Development sponsored a field study of portable technologies for testing for lead in paint in three U.S. cities in 1993. Six chemical test kits and six X-ray fluorescence instruments, which represented the two main types of portable technologies available for residential lead testing at that time, were evaluated. Painted building components in single-family and multifamily housing units were selected to assess the performance of these products under real-world conditions. The study found that the chemical test kits were not effective in distinguishing lead-based paint, as defined by federal standards, from nonlead based paint. The X-ray fluorescence instruments were, under certain circumstances, found to be effective. The study filled an informational gap about the accuracy and precision of the portable lead-testing technologies. This article describes the design of the study and its major findings.