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- Andersson, Lena, et al.
(författare)
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Estimating trends in quartz exposure in Swedish iron foundries : predicting past and present exposures
- 2012
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Ingår i: Annals of Occupational Hygiene. - Oxford, United Kingdom : Oxford University Press. - 0003-4878 .- 1475-3162. ; 56:3, s. 362-372
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Tidskriftsartikel (refereegranskat)abstract
- Background: Swedish foundries have a long tradition of legally required surveys in the work place that, from the late 1960s onwards, included measurements of quartz. The availability of exposure data spanning almost 40 years presents a unique opportunity to study trends over that time and to evaluate the validity of exposure models based on data from shorter time spans. The aims of this study were (i) to investigate long term trends in quartz exposure over time, (ii) using routinely collected quartz exposure measurements to develop a mathematical model that could predict both historical and current exposure patterns, and (iii) to validate this exposure model with up-to-date measurements from a targeted survey of the industry.Methods: Eleven foundries, representative of the Swedish iron foundry industry, were divided into three groups based on the size of the companies, i.e. the number of employees. A database containing 2333 quartz exposure measurements for 11 different job descriptionswas used to create three models that covered time periods which reflected different work conditions and production processes: a historical model (1968– 1989), a development model (1990–2004), and a validation model (2005–2006). A linear mixed model for repeated measurements was used to investigate trends over time. In all mixed models, time period, company size, and job title were included as fixed (categorical) determinants of exposure. The within- and between-worker variances were considered to be random effects. A linear regression analysis was erformed to investigate agreement between the models. The average exposure was estimated for each combination of job title and company size.Results: A large reduction in exposure (51%) was seen between 1968 and 1974 and between 1975 and 1979 (28%). In later periods, quartz exposure was reduced by 8% per 5 years at best. In the first period, employees at smaller companies experienced ~50%higher exposure levels than those at large companies, but these differences became much smaller in later years. The furnace and ladle repair job were associated with the highest exposure, with 3.9–8.0 times the average exposure compared to the lowest exposed group. Without adjusting for this autonomous trend over time, predicting early historical exposures using our development model resulted in a statistically significant regression coefficient of 2.42 (R2 5 0.81), indicating an underestimation of historical exposure levels. Similar patterns were seen for other historical time periods. Comparing our development model with our validation model resulted in a statistically significant regression coefficient of 0.31, indicating an overestimation of current exposure levels.Conclusion: To investigate long-term trends in quartz exposure over time, overall linear trends can be determined by using mixed model analysis. To create individual exposure measures to predict historical exposures, it is necessary to consider factors such as the time period, type of job, type of company, and company size. The mixed model analysis showed systematic changes in concentration levels, implying that extrapolation of exposure estimates outside the range of years covered by measurements may result in underestimation or overestimation of exposure.
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| 2. |
- Antonsson, Ann-Beth, 1956-, et al.
(författare)
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Fatal Carbon Monoxide Intoxication After AcetyleneGas Welding of Pipes
- 2013
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press. - 0003-4878 .- 1475-3162. ; 57:5, s. 662-666
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Tidskriftsartikel (refereegranskat)abstract
- Acetylene gas welding of district heating pipes can result in exposure to high concentrations of carbon monoxide. A fatal case due to intoxication is described. Measurements of carbon monoxide revealed high levels when gas welding a pipe with closed ends. This fatality and these measurements highlight a new hazard, which must be promptly prevented.
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| 5. |
- Arshadi, Mehrdad, et al.
(författare)
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Emission of Volatile Aldehydes and Ketones from Wood Pellets under Controlled Conditions
- 2009
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 53, s. 797-805
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Tidskriftsartikel (refereegranskat)abstract
- Different qualities of biofuel pellets were made from pine and spruce sawdust according to an industrial experimental design. The fatty/resin acid compositions were determined by gas chromatography-mass spectrometry for both newly produced pellets and those after 2 and 4 weeks of storage. The aldehydes/ketones compositions were determined by high performance liquid chromatography at 0, 2, and 4 weeks. The designs were analyzed for the response variables: total fatty/resin acids and total aldehydes/ketones. The design showed a strong correlation between the pine fraction in the pellets and the fatty/resin acid content but the influence decreased over storage time. The amount of fatty/resin acids decreased similar to 40% during 4 weeks. The influence of drying temperature on the aldehyde/ketone emission of fresh pellets was also shown. The amounts of emitted aldehydes/ketones generally decreased by 45% during storage as a consequence of fatty/resin acid oxidation. The matrices of individual concentrations were subjected to multivariate data analysis. This showed clustering of the different experimental runs and demonstrated the important mechanism of fatty/resin acid conversion.
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| 8. |
- Blanco, Luis E., et al.
(författare)
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The determinants of dermal exposure ranking method (DERM) : A pesticide exposure assessment approach for developing countries
- 2008
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 0003-4878 .- 1475-3162. ; 52:6, s. 535-544
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Tidskriftsartikel (refereegranskat)abstract
- A new method for assessment of dermal exposure to pesticides in subsistence farmers by use of determinants of dermal exposure is described. The method, called the determinants of dermal exposure ranking method (DERM), is a combination of checklists and expert rating assessment. Thus, determinants are listed in a form, which is used to check their presence and to assess them using a simple algorithm based on two factors, the type of transport process (T value) and the area of body surface exposed (A value). In addition, the type of clothing worn during applications is included as a protection factor. We applied the DERM to real pesticide applications, characterizing dermal exposure and comparing DERM estimates with earlier developed semiquantitative visual scores based on fluorescent tracer, the total visual score (TVS) and contaminated body area (CBA). DERM showed a very good level of agreement with both the TVS (r = 0.69, P = 0.000) and the CBA (r = 0.67, P = 0.000). DERM allowed identification of the determinants that had the highest effect on exposure and the farmers with the highest exposure. In conclusion, DERM provided information on the determinants responsible for dermal exposure in a group of subsistence farmers. This can be useful to design monitoring and preventive programs, define priorities for intervention and prioritize and select most adequate measurement strategies. DERM promises to be a low-cost easy-to-use method to assess dermal exposure to pesticides in developing country conditions.
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| 9. |
- Burström, Lage, 1954-, et al.
(författare)
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Vibrotactile perception and effects of short-term exposure to hand-arm vibration
- 2009
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Ingår i: The Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 1475-3162 .- 0003-4878. ; 53:5, s. 539-47
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Tidskriftsartikel (refereegranskat)abstract
- This study clarifies whether the established frequency weighting procedure for evaluating exposure to hand-transmitted vibration can effectively evaluate the temporary changes in vibrotactile perception thresholds due to pre-exposure to vibration. In addition, this study investigates the relationship between changes of the vibrotactile perception thresholds and the normalized energy-equivalent frequency-weighted acceleration. The fingers of 10 healthy subjects, five male and five female, were exposed to vibration under 16 conditions with a combination of different frequencies, intensities, and exposure times. The vibration frequencies were 31.5 and 125 Hz and exposure lasted between 2 and 16 min. According to International Organization for Standardization (ISO) 5349-1, the energy-equivalent frequency-weighted acceleration for the experimental time of 16 min is 2.5 or 5.0 m s(-2) root-mean-square, corresponding to a 8-h equivalent acceleration, A(8), of approximately 0.5 and 0.9 m s(-2), respectively. A measure of the vibrotactile perception thresholds was conducted before the different exposures to vibration. Immediately after the vibration exposure, the acute effect was measured continuously on the exposed index finger for the first 75 s, followed by 30 s of measures every minute for a maximum of 10 min. If the subject's thresholds had not recovered, the measures continued for a maximum of 30 min with measurements taken every 5 min. Pre-exposure to vibration significantly influenced vibrotactile thresholds. This study concludes that the influence on the thresholds depends on the frequency of the vibration stimuli. Increased equivalent frequency-weighted acceleration resulted in a significant change in threshold, but the thresholds were unaffected when changes in the vibration magnitude were expressed as the frequency-weighted acceleration or the unweighted acceleration. Moreover, the frequency of the pre-vibration exposure significantly influenced (up to 25 min after exposure) recovery time of the vibrotactile thresholds. This study shows that the frequency weighting procedure in ISO 5349-1 is unable to predict the produced acute changes in the vibrotactile perception. Moreover, the results imply that the calculation of the 'energy-equivalent' frequency-weighted acceleration does not reflect the acute changes of the vibration perception thresholds due to pre-exposure to vibration. Furthermore, when testing for the vibrotactile thresholds, exposure to vibration on the day of a test might influence the results. Until further knowledge is obtained, the previous practice of 3 h avoidance of vibration exposure before assessment is recommended.
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