Correlation of the exposure to a pollutant with a task-related action or workplace: the CAPTIV system.
(25/1747)
Usually, measurement of pollution at the workplace is performed by air sampling on solid absorbents and filters. The information obtained is the mean value of worker exposure over the sampling period. The use of specific sensors for chemicals can give complementary information, namely continuous exposure information. The CAPTIV system permits one to centralize and store this information along with a video system which restores the images of the workplace. Also, the stored video sequences, correlated to specified exposures, can be found automatically. This gives a rich information resource. In particular it allows one to correlate the occupational activity with the exposure level. The analysis of collected information may lead to advice on good practice at the workplace or even to proposals for modification of existing equipment and processes. A huge quantity of information to be processed is obtained with this new approach. The best use of it can only be made with the help of a high capacity processing tool. That is the reason why CAPTIV has been equipped with a data processor support system. At the end of this paper, we present an example of using CAPTIV to study a stone-cutting work station. (+info)
Determinants of exposure to inhalable particulate, wood dust, resin acids, and monoterpenes in a lumber mill environment.
(26/1747)
In a lumber mill in the northern inland region of British Columbia, Canada, we measured inhalable particulate, resin acid, and monoterpene exposures, and estimated wood dust exposures. Potential determinants of exposure were documented concurrently, including weather conditions, tree species, wood conditions, jobs, tasks, equipment used, and certain control measures. Over 220 personal samples were taken for each contaminant. Geometric mean concentrations were 0.98 mg/m3 for inhalable particulate, 0.49 mg/m3 for estimated wood dust, 8.04 micrograms/m3 for total resin acids, and 1.11 mg/m3 for total monoterpenes. Multiple regression models for all contaminants indicated that spruce and pine produced higher exposures than alpine fir or mixed tree species, cleaning up sawdust increased exposures, and personnel enclosure was an effective means of reducing exposures. Sawing wood in the primary breakdown areas of the mill was the main contributor to monoterpene exposures, so exposures were highest for the barker operator, the head rig operator, the canter operator, the board edgers, and a roving utility worker in the sawmill, and lowest in the planer mills (after kiln drying of the lumber) and yard. Cleaning up sawdust, planing kiln-dried lumber, and driving mobile equipment in the yard substantially increased exposures to both inhalable particulate and estimated wood dust. Jobs at the front end of the sawmill where primary breakdown of the logs takes place had lower exposures. Resin acid exposures followed a similar pattern, except that yard driving jobs did not increase exposures. (+info)
Occupational exposure to dust in quartz manufacturing industry.
(27/1747)
Owing to the abundance of a sedimentary rock, 65 small-scale quartz manufacturing enterprises, employing 650 workers, have been established in the region studied. Quartz powder manufacturing involves various processes and operations, such as manual handling of quartz stones, crushing, grinding, sieving, screening, mixing, storing and bagging. Results demonstrate that each of these operations generates high concentrations of airborne 'total' dust and respirable dust, which contain a very high percentage (> 75%) free silica. The estimated average exposure to airborne 'total' dust was 22.5 mg m-3 (Permissible Limit of Exposure 1.08 mg m-3), and respirable dust 2.93 mg m-3 (PLE 0.36 mg m-3). This shows that 'total' dust exposure was 7.7 times higher than respirable dust. Since the present work systems and practices may pose a serious health risk to the workers, public and the environment, suitable preventive and control measures have been suggested for improvement in the workplace. (+info)
Occupational exposure to lead--granulometric distribution of airborne lead in relation to risk assessment.
(28/1747)
The amount of airborne lead absorbed by the body during occupational exposure depends not only on lead concentration in workplace air, but also on the granulometric distribution of the aerosol. The Occupational Safety and Health Administration (OSHA) set the lead Permissible Exposure Limit (PEL) at 50 micrograms/m3 on the basis of Bernard's model and a number of assumptions, including assumption "C", which predicts that the first 12.5 micrograms/m3 are made up of fine particles (aerodynamic diameter < 1 micron) whereas the remaining 12.5 micrograms/m3 consist of particles > 1 micron. Occupational exposure to airborne lead at a concentration of 50 micrograms/m3 and a granulometric distribution calculated according to the above mentioned assumption, leads, in the model, to a mean blood level of 40 micrograms/dl. In the present study, we tested the validity of assumption "C" in the environmental air of a factory that manufactured crystal glassware containing 24% lead oxide. An 8-stage impactor was used to measure the particle size of airborne dust collected from personal and area samplings. Results indicate that, on the whole, assumption "C" cannot be considered valid in the work environment investigated in this study. As a result, lead absorption levels in exposed workers may be noticeably different from those predicted by the OSHA model. We therefore suggest that in order to make a correct evaluation of the risk of occupational exposure to lead, it is essential to integrate total airborne lead concentration with a measurement of the granulometric distribution of the aerosol. (+info)
Environmental measurements of total dust and fiber concentration in manufacturer and user of man-made mineral fibers.
(29/1747)
Man-made mineral fibers (MMMF), most of which are referred to as man-made vitreous fibers (MMVF), are mostly amorphous silicates manufactured from glass, rock, or other minerals. Analysis for MMMF have been restricted largely to the measurement of total airborne mass concentrations, but more recently to the determination of airborne fiber levels by phase contrast optical microscopy. In Korea, many small factories are related with manufacturing and using MMMF without any special evaluation of environmental measurements. Though MMMF are known as the substitute of asbestos and their toxicity are regarded as very low, MMMF do not totally excluded from the respiratory and/or skin diseases now. Therefore, we evaluated the environments of many workplaces with total dust and fiber concentration. Most dust and fiber concentrations were below threshold limit value (TLV) at various industries and working processes. However, these data showed a slight relationship between total dust and fiber concentration. (+info)
Exposure to hexavalent chromium does not increase 8-hydroxydeoxyguanosine levels in Korean chromate pigment workers.
(30/1747)
This study was performed to determine whether chromium exposure increased 8-hydroxydeoxyguanosine levels in respiratory epithelial and white blood cells of chromate pigment workers. The subjects of this study were 22 chromium pigment workers and 16 controls in a chromate pigments factory. To estimate the level of exposure, hexavalent chromium concentrations in the factory air were measured. Chrominum concentrations of venous blood and spot urine, and 8-hydroxydeoxyguanosine levels in DNA extracted from sputum and white blood cells were determined. Correlation coefficients were calculated between them and their statistical significance was tested. Hexavalent chromium concentration in the factory air ranged from below limit of detection to 0.5150 mg/m3. Chromium levels in blood and 8-hydroxydeoxyguanosine levels in DNA extracted from venous blood and sputum were not statistically different between the two groups. Urine chromium level was significantly higher among workers. Among the correlation coefficients between blood chromium concentration, urine chromium concentration, blood 8-OH-dG level, and sputum 8-OH-dG level, none was statistically significant for workers, controls, and total subjects. Duration of employment did not show any significant correlation with those four variables, either. These results suggest that neither the hydroxyl radical nor 8-hydroxydeoxyguanosine is formed by the reduction of hexavalent chromium, or that one or both of these is formed and then effectively removed by oxygen free radical scavengers or 8-hydroxydeoxyguanosine repair enzymes. Since increased exposure to hexavalent chromium did not result in increased 8-hydroxydeoxyguanosine levels, it is unlikely that hexavalent chromium induces lung cancer through 8-hydroxydeoxyguanosine formation. (+info)
Efficiency of automotive cabin air filters to reduce acute health effects of diesel exhaust in human subjects.
(31/1747)
OBJECTIVES: To evaluate the efficiency of different automotive cabin air filters to prevent penetration of components of diesel exhaust and thereby reduce biomedical effects in human subjects. Filtered air and unfiltered diluted diesel exhaust (DDE) were used as negative and positive controls, respectively, and were compared with exposure to DDE filtered with four different filter systems. METHODS: 32 Healthy non-smoking subjects (age 21-53) participated in the study. Each subject was exposed six times for 1 hour in a specially designed exposure chamber: once to air, once to unfiltered DDE, and once to DDE filtered with the four different cabin air filters. Particle concentrations during exposure to unfiltered DDE were kept at 300 micrograms/m3. Two of the filters were particle filters. The other two were particle filters combined with active charcoal filters that might reduce certain gaseous components. Subjective symptoms were recorded and nasal airway lavage (NAL), acoustic rhinometry, and lung function measurements were performed. RESULTS: The two particle filters decreased the concentrations of diesel exhaust particles by about half, but did not reduce the intensity of symptoms induced by exhaust. The combination of active charcoal filters and a particle filter significantly reduced the symptoms and discomfort caused by the diesel exhaust. The most noticable differences in efficacy between the filters were found in the reduction of detection of an unpleasant smell from the diesel exhaust. In this respect even the two charcoal filter combinations differed significantly. The efficacy to reduce symptoms may depend on the abilities of the filters investigated to reduce certain hydrocarbons. No acute effects on NAL, rhinometry, and lung function variables were found. CONCLUSIONS: This study has shown that the use of active charcoal filters, and a particle filter, clearly reduced the intensity of symptoms induced by diesel exhaust. Complementary studies on vehicle cabin air filters may result in further diminishing the biomedical effects of diesel exhaust in subjects exposed in traffic and workplaces. (+info)
Long-term effects on the olfactory system of exposure to hydrogen sulphide.
(32/1747)
OBJECTIVE: To study chronic effects of hydrogen sulphide (H2S) on cranial nerve I (nervi olfactorii), which have been only minimally described. METHODS: Chemosensations (smell and taste) were evaluated in eight men who complained of continuing dysfunction 2-3 years after the start of occupational exposure to H2S. Various bilateral (both nostrils) and unilateral (one nostril at a time) odour threshold tests with standard odorants as well as the Chicago smell test, a three odour detection and identification test and the University of Pennsylvania smell identification test, a series of 40 scratch and sniff odour identification tests were administered. RESULTS: Six of the eight patients showed deficits of various degrees. Two had normal scores on objective tests, but thought that they continued to have problems. H2S apparently can cause continuing, sometimes unrecognised olfactory deficits. CONCLUSION: Further exploration into the extent of such problems among workers exposed to H2S is warranted. (+info)