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- Axelsson, Sara, 1975-
(författare)
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Resin acids in commercial products and the work environment of Swedish wood pellets production : Analytical methodology, occurrence and exposure
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aims of the work this thesis is based upon were to develop convenient analytical procedures for determining resin acids in biological and environmental matrices, and apply them to enhance understanding of the occurrence, exposure to and uptake by exposed individuals of resin acids. Particular focus has been on the workplace environment of the Swedish wood pellets industry. Sample extraction procedures and high-performance liquid chromatography/electrospray ionisation-mass spectrometry (HPLC/ESI-MS) methodologies were developed for measuring resin acids in dust, skin and urine samples. Chromatographic separation of abietic (AA) and pimaric acid was achieved by using a polar-embedded C12 stationary phase. The HPLC/ESI-MS method avoids undesirable oxidation of AA, which was found to occur during the derivatisation step in the standard MDHS 83/2 gas chromatography/flame ionisation detection (GC/FID) methodology, leading to false observations of both AA and the oxidation product 7-oxodehydroabietic acid (7-OXO). Personal exposures to resin acids in the Swedish wood pellet production industry were found to be lower, on average, than the British Occupational Exposure Limit for rosin (50 µg/m3). The oxidised resin acid 7-OXO, was detected in both dust and skin samples indicating the presence of allergenic resin acids. A correlation between air and post-shift urinary concentrations of dehydroabietic acid (DHAA), and a trend towards an increase in urinary 7-OXO during work shifts, were also observed. Whether the increase in 7-OXO was due to direct uptake or metabolism of other resin acids cannot be concluded from the results. An efficient HPLC/UV methodology with diode-array detection was developed for screening commercial products for rosin that could be used in laboratories lacking mass spectrometers. Very high concentrations of free resin acids were detected in depilatory wax strips using the method.
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| 2. |
- Hagenbjörk-Gustafsson, Annika, 1956-
(författare)
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Validation of diffusive samplers for nitrogen oxides and applications in various environments
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim of this thesis was to validate diffusive samplers for measurements of nitrogen dioxide (NO2) and nitrogen oxides (NOx). The Willems badge was validated for NO2 measurements both in laboratory tests and in field tests (Paper I-II). The sampling rate was 40.0 mL/min for ambient air concentrations and 46.0 mL/min for higher concentrations. No effects of different factors on sampling rate were found except for a reduced sampling rate at low wind velocity. The results of the laboratory validation were confirmed in field tests in ambient air and with personal sampling. The correlation between diffusive samplers and the reference monitor was good for ambient measurements. In conclusion, the Willems badge performs well at wind velocities down to 0.3 m/s, and this makes it suitable for personal sampling but less suitable for measurements in indoor air where the wind velocity is lower. Paper III reports about the field validation of the Ogawa diffusive samplers. Absolute humidity and temperature were found to have the strongest effect on sampling rate with lower uptake rates at low absolute humidity or temperature. The sampling rates above 0 °C were 8.6 mL/min for NO2 and 9.9 mL/min for NOx. NO2 and NOx concentrations that were determined using the manufacturer’s protocol were either underestimated or overestimated. The agreement between concentrations measured by the Ogawa sampler and the reference monitor was improved when field-determined sampling rates were used to calculate concentrations. Paper IV is based on a study with the aim of assessing the exposure of the Swedish general population to NO2 and some carcinogenic substances. The surveys were performed in one of five Swedish cities every year. In each survey, personal measurements of NO2 and some carcinogenic substances were conducted on 40 randomly selected individuals. In the study presented in this thesis, the NO2 part of the study is in focus and results were available for eight surveys conducted across the five cities. The estimated arithmetic mean concentration for the general Swedish population was 14.1 μg/m3. The exposure level for NO2 was higher for smokers compared with non-smokers, and the NO2 exposure levels were higher for people who had gas stoves at home or who were exposed at their workplace. The exposure was lower for those who had oil heating in their houses.
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| 3. |
- Hagström, Katja, 1975-
(författare)
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Occupational exposure during production of wood pellets in Sweden
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aims of the studies underlying this thesis were to assess workers’ air exposure to wood dust and various chemicals, and to evaluate the variability in exposure and occupational dermal exposure to resin acids during the production of wood pellets in Sweden. Personal air measurements of wood dust, monoterpenes, resin acids and nitrogen dioxide (as a marker of diesel exhaust), accompanied by area measurements of these substances, VOCs and carbon monoxide, were performed at up to ten plants. Repeated measurements were also performed to evaluate within- and between-worker variability, determinants of exposure, the probability that a worker’s mean exposure exceeded the occupational exposure limit, OEL (overexposure), and the bias in the exposure-response relationship (attenuation).Dermal exposure was measured at the forehead, neck, forearm and hand using a tape-stripping method, in which a strip of adhesive tape is applied to the skin and then removed along with the outermost layer of the skin and chemicals adsorbed to this layer. The workers’ exposure to wood dust was high (mean: 2.4 mg/m3), with 35−42 % of the measurements above the Swedish OEL of 2 mg/m3. The exposure is also classified as unacceptable due to the calculated levels of overexposure. Exposure to resin acids like 7-oxodehydroabietic acid and dehydroabietic acid was identified, which has not been previously observed in the wood industry, with mean sum levels of 2.4 _g/m3. Levels of monoterpenes, nitrogen dioxide, VOCs and carbon monoxide were all below their Swedish OELs. A factor that influenced the level of exposure to wood dust and resin acids was the nature of the work done, notably cleaning operations, like sweeping, which increased the exposure slightly. The attenuation was high for the individual-based model, and at least 12 repeated measurements were needed to yield a bias in the exposureresponse relationship of _10 %. The results also showed that dermal exposure to resin acids occurs in these plants, which has not been shown before, and provided indications of both increased exposure during a work shift and diffusion into the skin. The main conclusion is that wood dust exposure at these levels is likely to have implications for the workers’ health in the long run, and, therefore, it is important to reduce exposure to wood dust in this industry.
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