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Average Exposure (average + exposure)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Exposure, health complaints and cognitive performance among employees of an MRI scanners manufacturing department

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2006
Frank de Vocht MSc
Abstract Purpose To assess sensory effects and other health complaints that are reported by system testers working near magnetic resonance imaging (MRI) magnets, realizing that it is believed that exposure up to 8 T is safe for humans. Materials and Methods Levels of exposure to static magnetic fields (SMFs), movement speed during exposure, health complaints, and cognitive performance among employees in an MRI-manufacturing department and at a reference department have been analyzed. Mercury concentrations in urine samples were determined to analyze whether they depend on exposure to SMFs. Results Average exposure of system testers was 25.9 mT/8 hours at a 1.0-T system and 40.4 mT/8 hours at a 1.5-T system. Vertigo, metallic taste, and concentration problems were more reported among workers of MRI-fabrication than in the reference department. Cognitive performance was tested outside the SMF, and no significant changes were detected. Conclusion This study suggests that any effects on cognitive functions are acute and transient and disappear rapidly after exposure has ended. All complaints, except for headaches, were more frequently reported by "fast movers" than by "slow movers," and depended on field strength and duration of exposure. Mercury-levels in urine were not affected. J. Magn. Reson. Imaging 2006. © 2005 Wiley-Liss, Inc. [source]

Noise exposures aboard catcher/processor fishing vessels

AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 8 2006
Richard L. Neitzel MS
Abstract Background Commercial fishing workers have extended work shifts and potential for 24 hr exposures to high noise. However, exposures in this industry have not been adequately characterized. Methods Noise exposures aboard two catcher/processors (C/P) were assessed using dosimetry, sound-level mapping, and self-reported activities and hearing protection device (HPD) use. These data were combined to estimate work shift, non-work, and 24 hr overall exposure levels using several metrics. The length of time during which HPDs were worn was also used to calculate the effective protection received by crew members. Results Nearly all workers had work shift and 24 hr noise levels that exceeded the relevant limits. After HPD use was accounted for, half of the 24 hr exposures remained above relevant limits. Non-work-shift noise contributed nothing to 24 hr exposure levels. HPDs reduced the average exposure by about 10 dBA, but not all workers wore them consistently. Conclusions The primary risk of hearing loss aboard the monitored vessels comes from work shift noise. Smaller vessels or vessels with different layouts may present more risk of hearing damage from non-work periods. Additional efforts are needed to increase use of HPDs or implement noise controls. Am. J. Ind. Med. 2006. © 2006 Wiley-Liss, Inc. [source]

Metal and non-metal miners' exposure to crystalline silica, 1998,2002

AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 7 2006
James L. Weeks ScD
Abstract Background Crystalline silica is well known to cause silicosis and other diseases. Exposure is common in the mining industry and consequently, the US Mine Safety and Health Administration (MSHA) evaluates miners exposure to silica to determine compliance with its exposure limit. Methods MSHA exposure measurements were obtained for the 5-year period from 1998 to 2002 and average exposure was calculated classified by occupation and by mine. Evaluation criteria were whether average values exceeded MSHA's permissible exposure limit or the limit recommended by the National Institute for Occupational Safety and Health (NIOSH), whether there was a risk of exposure to freshly fractured silica, and whether there was a risk of a high rate of exposure to silica. Results Miners in certain jobs are exposed to silica above permissible and recommended exposure limits. Some miners may also be exposed at a high rate or to freshly fractured silica. Conclusions Known dust control methods should be implemented and regular medical surveillance should be provided. Am. J. Ind. Med. 49:523,534, 2006. © 2006 Wiley-Liss, Inc. [source]

Personal exposure to mobile communication networks and well-being in children,A statistical analysis based on a functional approach

BIOELECTROMAGNETICS, Issue 4 2009
Anja Kühnlein
Abstract The MobilEe-study was the first cross-sectional population-based study to investigate possible health effects of mobile communication networks on children using personal dosimetry. Exposure was assessed every second resulting in 86,400 measurements over 24 h for each participant. Therefore, a functional approach to analyze the exposure data was considered appropriate. The aim was to categorize exposure taking into account the course of the measurements over 24 h. The analyses were based on the 480 maxima of each 3 min time interval. Exposure was classified using a nonparametric functional method. Heterogeneity of a sample of functional data was assessed by comparing the functional mode and mean of the distribution of a functional variable. The partition was built within a descending hierarchical method. The resulting exposure groups were compared with categories derived from a standard method, which used the average exposure over 24 h and set the cut-off at the 90th percentile. The functional classification resulted in a splitting of the exposure data into two groups. Plots of the mean curves showed that the groups could be interpreted as children with "low exposure" (88%) and "higher exposure" (12%). These groups were comparable with categories of the standard method. No association between the categorized exposure and well-being was observed in logistic regression models. The functional classification approach yielded a plausible partition of the exposure data. The comparability with the standard approach might be due to the data structure and should not be generalized to other exposures. Bioelectromagnetics 30:261,269, 2009. © 2009 Wiley-Liss, Inc. [source]

Acute symptoms associated with asphalt fume exposure among road pavers,

AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 9 2006
Allison L. Tepper PhD
Background Although asphalt fume is a recognized irritant, previous studies of acute symptoms during asphalt paving have produced inconsistent results. Between 1994 and 1997, the National Institute for Occupational Safety and Health (NIOSH) evaluated workers at seven sites in six states. Methods NIOSH (a) measured exposures of asphalt paving workers to total (TP) and benzene-soluble particulate (BSP), polycyclic aromatic compounds, and other substances; (b) administered symptom questionnaires pre-shift, every 2 hr during the shift, and post-shift to asphalt exposed and nonexposed workers; and (c) measured peak expiratory flow rate (PEFR) of asphalt paving workers when they completed a symptom questionnaire. Results Full-shift time-weighted average exposures to TP and BSP ranged from 0.01 to 1.30 mg/m3 and 0.01 to 0.82 mg/m3, respectively. Most BSP concentrations were <0.50 mg/m3. Asphalt workers had a higher occurrence rate of throat irritation than nonexposed workers [13% vs. 4%, odds ratio (OR),=,4.0, 95% confidence interval (CI): 1.2,13]. TP, as a continuous variable, was associated with eye (OR,=,1.34, 95% CI: 1.12,1.60) and throat (OR,=,1.40, 95% CI: 1.06,1.85) symptoms. With TP dichotomous at 0.5 mg/m3, the ORs and 95% CIs for eye and throat symptoms were 7.5 (1.1,50) and 15 (2.3,103), respectively. BSP, dichotomous at 0.3 mg/m3, was associated with irritant (eye, nose, or throat) symptoms (OR,=,11, 95% CI: 1.5,84). One worker, a smoker, had PEFR-defined bronchial lability, which did not coincide with respiratory symptoms. Conclusions Irritant symptoms were associated with TP and BSP concentrations at or below 0.5 mg/m3. Am. J. Ind. Med. 49:728,739, 2006. © 2006 Wiley-Liss, Inc. [source]