American Industrial Hygiene Association journal最新文献

This study is based on an ergonomic job analysis designed to develop a hazard prevention program for the premixing and compounding processes in animal health products plants. Animal health products plants are "pharmaceutical facilities" for livestock or domestic animals. A hazardous aerosol (highly concentrated antibiotics, anthelmintics, mineral oil, and animal hormones) is generated in the premixing or compounding processes. The animal health premixing jobs are heavy-duty jobs and have high potential for chemical exposure, heat stress, and ergonomic hazards. Ergonomic job analysis was used to recognize, identify, and evaluate actuarial and potential risks of injures or irritations. Chemical hazards and eight ergonomic factors were discussed: (1) forceful exertions, (2) awkward postures, (3) localized contract stresses, (4) vibration, (5) noise, (6) temperature extremes, (7) repetitive activities, and (8) prolonged activities. The results show that (1) current practices do not violate occupational safety and health regulations or recommended guidelines, but that hazards should be identified to protect worker health and safety; (2) for chemical hazards prevention, operators wear whole-body protection equipment, which also causes heat stress and increases the noise level in the work zone; and (3) the loading weight of the bags used needs to be reduced.

This study investigated two methods for analyzing composite dust wipes for lead. The term composite means two or more wipes collected from common components in a dwelling that are combined in the field and analyzed as a single sample. Two methods--a modified Environmental Protection Agency (EPA) Method 3050A and a Wisconsin Occupational Health Laboratory (WOHL) method--were selected based on their anticipated ability to handle the added mass of materials and dust expected in a composite. The study used off-the-shelf wipes to prepare single-, two-, and four-wipe samples. Wipes were spiked with a standard reference material at either a low dust loading level or a high level, and three laboratories analyzed the samples using both methods and both flame atomic absorption spectrometry and inductively coupled plasma-atomic emission spectrometry techniques (ICP). Good agreement with known spiked levels was possible using either method; the modified EPA 3050A showed particular promise. When up to four wipes were combined, all three laboratories found that modified EPA Method 3050A resulted in recoveries between 89 and 101% of the known standard. Although it was possible to achieve good agreement with spiked levels using the WOHL method, some difficulties were encountered, particularly when followed by ICP analysis and when using four wipes. The increased time required to digest the multiwipe composites was not proportional to the number of wipes in a composite: the two- and four-wipe composites did not take two to four times as long as a single-wipe sample. Laboratory analysis of a four-wipe sample cost an average of 65% less than analysis of four single-wipe samples for each method.

A study tested whether measures of equivalent resistance (X values) and ratios of static pressure (SPratio) for given ducts of contaminant control exhaust ventilation systems were independent of substantial changes to airflow level and to changes to resistance of other ducts within the same full-scale five-branch system. In a factorial study design, four airflow levels were achieved by changing fan rotation rate while resistances to flow for specific branch ducts were changed independently by adjusting slidegate dampers to various settings. For each damper insertion depth (including fully open), the results demonstrated substantial invariance for branch X values (few greater than 5%), SPratio (few greater than 3%), and fraction of airflow to each duct (few greater than 2%). X-values for submains were much less stable, changing by 20% or more with changes to other parts of the system. For the same conditions, hood static pressures changed by as much as 96% (with standard deviation of 40%). The results suggest that before and after values of X and SPratios should be more reliable bases for indicating alterations than comparison of observed static pressures. The stability of airflow distributions with substantial changes in airflow suggests that one could adjust airflow distribution (e.g., with dampers) without considering whether the fan speed was set correctly, leaving fan adjustments for a final step.

This article reviews the analytical methods for crystalline silica polymorphs and summarizes promising techniques for compliance with health-related regulations. X-ray diffraction analysis appears to be the most promising method of determining quartz and cristobalite content at this threshold in many bulk mineral and chemical systems. Other analytical techniques can be used in some mineral and chemical assemblages, but usually lack polymorph specificity or sensitivity. All analytical methods benefit from concentration techniques that do not alter crystalline properties of silicas. National Institute of Occupational Safety and Health (NIOSH) Analytical Method 7601 as written suffers from destruction of the mineral residue containing crystalline silica polymorphs after dissolution of many silicate minerals in phosphoric acid and may also include digestion-resistant silicate minerals, but it is a promising concentration method for other analytical methods such as NIOSH Analytical Method 7500 (X-ray diffraction).

Concentrations of airborne culturable fungi were measured in the kitchen of a bakery in Boston, Mass., to evaluate variabilities associated with common worker activities, outdoor aerosol distributions, and season. Activities were categorized as early morning preparation, cornmeal sifting and tossing, flour dumping and mixing, sweeping, and low activity. Sets of measurements were taken over 1 day in spring and 1 day in summer. Fungal concentrations were measured using a one-stage culture plate impactor, and bulk samples were taken from suspected fungal reservoirs within the bakery and subsequently cultured. Compared with the low activity category, elevated levels of total culturable fungi were found during all other activities, with the amount of increase closely related to individual worker activity as well as outdoor concentrations and initial bakery conditions. In the spring, Penicillium was the dominant genus showing activity-related elevations in concentrations, while Cladosporium was the dominant genus during the summer. Clearly, due to variabilities in worker activities and ambient fungal concentrations, a standardized sampling protocol involving a large sample size over multiple days is needed to estimate accurately exposure to either total airborne fungi or specific fungal taxa.

This short review outlines the contribution of modeling techniques, particularly physiologically based pharmacokinetic (PBPK) modeling, in promulgating biological monitoring as a practical tool for the occupational health professional. The impact of modeling techniques is discussed in helping to establish the relevant biomarkers to measure, the appropriate time of sampling, and the relationship between atmospheric exposure limits and concentration of biological analyte. Of particular interest is the use of "population" PBPK techniques. These can explore the influence of physiological differences between workers or of particular susceptible subgroups (e.g., pregnant women, breast-feeding mothers, and infants) on the relationship between atmospheric exposure levels and biomarker concentration. Such techniques will become more widely used as biological monitoring guidance values (e.g., biological exposure indices, biological tolerance values) are increasingly established by various international professional and regulatory bodies.

This study examined the incidence of violations of occupational safety and health standards for respiratory protection in hospitals. Data from Occupational Safety and Health Administration inspections that occurred in hospitals and resulted in violations of the respiratory protection standards were examined. From July 1, 1990, to June 30, 1995, the complaint rates for hazards in the workplace significantly increased. During 1990-1991, tuberculosis hazard complaint inspections rates were approximately 5 complaints per 1000 complaint inspections conducted. During 1994-1995, tuberculosis hazard complaint inspections rates were approximately 76 complaints per 1000 complaint inspections conducted, representing an increase of over 15 times. During this same period, the percentage of respiratory protection violations in relation to all violations doubled. Increased employee awareness of the hazards and current safety laws could have contributed to the increased frequency of employee complaints, leading to increases in inspections, violations, and fines. Employers must adhere to the current safety and health requirements specifically as they pertain to respiratory hazards and tuberculosis.

This study determined the deviations between pitot traverses taken under "ideal" conditions--at least seven duct diameter's lengths (i.e., distance = 7D) from obstructions, elbows, junction fittings, and other disturbances to flows--with those taken downstream from commonplace disturbances. Two perpendicular 10-point, log-linear velocity pressure traverses were taken at various distances downstream of tested upstream conditions. Upstream conditions included a plain duct opening, a junction fitting, a single 90 degrees elbow, and two elbows rotated 90 degrees from each other into two orthogonal planes. Airflows determined from those values were compared with the values measured more than 40D downstream of the same obstructions under ideal conditions. The ideal measurements were taken on three traverse diameters in the same plane separated by 120 degrees in honed drawn-over-mandrel tubing. In all cases the pitot tubes were held in place by devices that effectively eliminated alignment errors and insertion depth errors. Duct velocities ranged from 1500 to 4500 ft/min. Results were surprisingly good if one employed two perpendicular traverses. When the averages of two perpendicular traverses was taken, deviations from ideal value were 6% or less even for traverses taken as close as 2D distance from the upstream disturbances. At 3D distance, deviations seldom exceeded 5%. With single diameter traverses, errors seldom exceeded 5% at 6D or more downstream from the disturbance. Interestingly, percentage deviations were about the same at high and low velocities. This study demonstrated that two perpendicular pitot traverses can be taken as close as 3D from these disturbances with acceptable (< or = 5%) deviations from measurements taken under ideal conditions.

The effects of exposure misclassification on the interpretation of results of occupational epidemiological studies has been widely investigated and reported. Usually, only the direct effects of misclassification have been considered or simple estimates of misclassification rates have been assigned to various types of exposure estimation processes. Lifelong job profile data obtained from a previously published case-control study provided complete or nearly complete job histories of 511 decedents. An analysis of these work histories and the comparison of exposures related to longest-held job to estimated total lifetime exposures suggest that single job-based exposure estimates may lead to significant exposure misclassification rates. In addition, the appearance of shorter duration jobs in a study population occurring predominantly early in the work history may exacerbate problems associated with exposure misclassification. While few specific suggestions emerge from this analysis, the inclusion of extensive recording of the work history of study subjects emerges as a reasonable basis for the investigation and potential reduction of secondary misclassification of exposures in occupational epidemiological studies.