RESUMEN
A cross-sectional health study was performed at four footwear and one equipment factory in Thailand to evaluate the prevalence of chemical- and ergonomic-related symptoms in Thai factory workers and to investigate associations between these symptoms and exposures to organic solvents, isocyanates and ergonomic risks. A 10-page health questionnaire was administered to 1784 workers across the four footwear and equipment factories. A total of 1675 questionnaires were returned, yielding a 94% response rate. The questionnaires asked about age, gender, use of chemicals, use of personal protective equipment and health outcomes. Without exception, the percentages of workers reporting symptoms after being hired were higher than those reporting symptoms before being hired for all the factories. The highest symptom percentages were related to ergonomic stressors. Multiple logistic regression was used to calculate adjusted prevalence odds ratios and 95% confidence intervals. This study showed that adverse health effects experienced by footwear and equipment factory workers are associated with occupational exposures to chemicals (volatile organic solvents and water-based adhesives) and ergonomic hazards.
Asunto(s)
Ergonomía , Enfermedades Profesionales/epidemiología , Solventes/toxicidad , Adulto , Femenino , Encuestas Epidemiológicas , Humanos , Masculino , Enfermedades Profesionales/etiología , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , Prevalencia , Zapatos , Solventes/análisis , Tailandia/epidemiologíaRESUMEN
This research reports on a pilot industrial hygiene study that was performed at four footwear factories and two equipment factories in Thailand. Workers in these factories were exposed through inhalation and dermal contact to a large number of organic vapors from solvents and cements that were hand applied. In addition, these workers were exposed to highly toxic isocyanates primarily through the dermal route. A total of 286 personal air samples were obtained at the four footwear factories using organic vapor monitors; individual job tasks were monitored using a real-time MIRAN Spectrometer. A total of 64 surface, tool, or hand samples were monitored for isocyanates using surface contamination detectors. Real-time measurements were also obtained for organic vapors in two equipment factories. From 8% to 21% of the workers sampled in each footwear factory were overexposed to mixtures of chemicals from solvents and cements. Up to 100% of the workers performing specific job tasks were overexposed to mixtures of chemicals. From 39% to 69% of the surface samples were positive for unreacted isocyanates. Many of the real-time measurements obtained in the equipment factories exceeded occupational exposure limits. Personal protective equipment and engineering controls were inadequate in all of the factories.
Asunto(s)
Contaminantes Ocupacionales del Aire/análisis , Monitoreo del Ambiente/métodos , Exposición Profesional/análisis , Zapatos , Piel , Industria Textil , Aerosoles/análisis , Contaminantes Ocupacionales del Aire/normas , Femenino , Pie , Humanos , Isocianatos/aislamiento & purificación , Masculino , Exposición Profesional/normas , Compuestos Orgánicos/aislamiento & purificación , Ropa de Protección , Tailandia , Ventilación/métodos , Ventilación/normasRESUMEN
Numerical studies were performed to evaluate a new air monitoring method for reconstructing chemical exposures and source emissions, based upon optical remote sensing (ORS) and computed tomography (CT). With an ORS-CT system, two-dimensional maps of chemical concentrations can be created that have good spatial and temporal resolution. The mathematical algorithm used to compute the distribution is critical for accurate and useable reconstructions of the concentrations. In this research, a novel reconstruction method was tested that uses maximum likelihood expectation maximization (MLEM) combined with two techniques called grid-translation and multi-grid (GT-MG). To evaluate this method, computer simulations were performed using 120 test maps of varying complexity and a simulated ORS system with four instruments and a total of 40 path-integrated measurements. The results were quantitatively compared with two previously used reconstruction methods (single-grid and grid-translation). Results using the GT-MG method were dramatically improved over previously used methods. Quantitatively, peak exposure errors were reduced by up to 85% and artifacts were dramatically minimized.
Asunto(s)
Contaminantes Atmosféricos/análisis , Algoritmos , Atmósfera/química , Monitoreo del Ambiente/métodos , Tomografía Computarizada por Rayos X/métodos , Simulación por Computador , Funciones de VerosimilitudRESUMEN
To effectively and accurately evaluate human exposures to chemicals, it is important to quantify mixtures of chemicals in air, at low levels, and in real time. The purpose of this study was to evaluate, in the field, a prototype of a new transportable instrument that can fill an important gap in methods available to industrial hygienists. This instrument is a cross between extractive and open-path Fourier Transform Infrared spectrometers and measures chemicals passively and in real time in the vicinity of the breathing zone. The spectrometer has a folded optical path that can be enclosed, similar to an extractive system. The enclosure can be removed, enabling the optical path to be open to the atmosphere; thus, the instrument could be operated as an open-path spectrometer. A field study was conducted in three different occupational settings, including a prosthodontics dental laboratory, a surgery recovery area, and a cytology laboratory. Chemicals that were identified and quantified included methyl methacrylate, nitrous oxide, xylene isomers, toluene, and ethanol. Simultaneous side-by-side sampling was conducted with the prototype instrument and recognized National Institute of Occupational Safety and Health (NIOSH) analytical methods. The distinct infrared "fingerprint" of each chemical made identification and quantification of multiple chemicals possible with the prototype instrument. This attribute allowed the industrial hygienist to quantify short-term exposures and ceiling levels, correlate work practices with concentration levels, evaluate the effectiveness of engineering controls, and identify the presence of unexpected compounds. There was no significant difference between the mean time-weighted averages (TWAs) of the prototype instrument and traditional methods (p > 0.03). Regression analysis found good correlation between the two methods with no significant differences between the slope and unity and between the y-intercept and zero (p > 0.03). The technology and design of the prototype instrument incorporated a unique combination of features and advantages not found in other methods or instruments. The instrument produced results comparable to recognized analytical methods under field conditions and shows promise as a powerful tool in industrial hygiene air monitoring applications.