| 761. |
- Persson, Ylva, et al.
(författare)
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Dioxins, chlorophenols and other chlorinated organic pollutants in colloidal and water fractions of groundwater from a contaminated sawmill site
- 2008
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Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 15:6, s. 463-471
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Tidskriftsartikel (refereegranskat)abstract
- Background, aim, and scope: The distribution of chlorinated organic contaminants in groundwater and the importance of colloids were studied in groundwater from a sawmill site contaminated by chlorophenol preservatives.Materials and methods: The groundwater was fractionated into three different size ranges: (1) >0.7 μm, (2) 0.4–0.7 μm and (3) 0.2–0.4 μm and the filtered water phase. The concentrations of chlorophenols (CP), chlorinated phenoxy phenols (PCPP), chlorinated diphenyl ethers (PCDE), chlorinated dibenzofurans (PCDF) and chlorinated dibenzo-p-dioxins (PCDD) were determined in each fraction. The colloids were characterised regarding the chemical composition using X-ray photoelectron spectroscopy (XPS).Results: Chlorophenols were mostly found in the water fraction and PCDD/Fs were found almost exclusively in the particulate fractions. For example, the filtered water phase contained 2,100 μg l−1 and 0.72 ng l−1 for CPs and PCDD/Fs, respectively, and the particulate fractions contained 27 μg l−1 and 32 ng l−1 for CPs and PCDD/Fs, respectively. XPS evaluation of the particulate phases showed no correlation between the surface chemistry of the particle properties and the distribution of chlorinated compounds.Discussion: The results suggest that groundwater transport of CPs, PCPPs, PCDEs and PCDD/Fs may occur from contaminated sawmill sites and that the colloid-facilitated transport, especially of PCDD/Fs, is substantial. The results correlated well with previous studies of compounds sorbed to dissolved organic carbon, which indicate that dissolved and colloidal organic carbon facilitated the transport of PCDEs, PCDFs and PCDDs particularly.Conclusions: Several classes of chlorinated compounds were readily detected in the groundwater samples. Due to the differences in their physicochemical properties, CPs, PCPPs, PCDEs and PCDD/Fs vary in their partitioning between colloidal fractions and the filtered groundwater. The proportion of the bound fraction increased with an increasing hydrophobicity of the chlorinated compounds. The groundwater transport of colloid-associated pollutants from the site may be significant.Recommendations and perspectives: The results imply that colloidal particles <0.7 μm are freely mobile in groundwater from this site. The groundwater transport of colloid-associated pollutants may be significant. However, the extent of the problem is not yet known and, thus, further research is needed to evaluate the impact of colloidal transport of hydrophobic organic contaminants. In Sweden alone, 400 to 500 sawmill sites are estimated to be contaminated with PCDD/Fs as a result of the former use of CP-based wood preservatives. The widespread use of CP mixtures for a variety of applications, including wood preservation, indicates that potential colloidal transport will be an issue of concern in many countries.
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| 762. |
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| 763. |
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| 764. |
- Persson, Ylva, et al.
(författare)
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Levels of chlorinated compounds (CPs, PCPPs, PCDEs, PCDFs and PCDDs) in soils at contaminated sawmill sites in Sweden.
- 2007
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 66:2, s. 234-42
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Tidskriftsartikel (refereegranskat)abstract
- Soil samples from five contaminated sawmill sites in Sweden were characterized with respect to chlorophenols (CP), chlorinated phenoxy phenols (PCPP, hydroxylated chlorinated diphenyl ethers), chlorinated diphenyl ethers (PCDE), chlorinated dibenzofurans (PCDF) and chlorinated dibenzo-p-dioxins (PCDD). The composition of chlorinated compounds in the soil samples was compared to the composition of two preservatives commonly used in the Scandinavian wood impregnation industry: the 2,3,4,6-tetrachlorophenol preservative called Ky-5 and the pentachlorophenol preservative Dowicide G. The levels of CPs in the soil samples ranged from 0.1 to 4500 mg kg−1 d.w., PCPPs from <0.15 to 940 mg kg−1 d.w., PCDEs from <38 to 6800 μg kg−1 d.w., PCDFs from 7.4 to 18 000 μg kg−1 d.w. and PCDDs from 9.9 to 35 000 μg kg−1 d.w. The resulting WHO-TEQ of PCDD/Fs in the soil samples ranged from 0.14 to 3000 μg kg−1 d.w. Despite a wide range of concentrations the congener compositions were similar within tetrachlorophenate and pentachlorophenate contaminated soils respectively. The contamination at each sawmill site may be linked to the use of either a tetrachlorphenol preservative, e.g. Ky-5, or a pentachlorophenol preservative, e.g. Dowicide G. Best-fit calculations were used to compare the chlorinated phenol contents of the preservatives to those of the soil samples. This revealed a positive correlation between the hydrophobicity (log Kow) of contaminants and the ratio of their levels in soil to preservatives. The relative abundance of the chlorinated compounds varied greatly between the five sites studied, suggesting that their transport parameters differ substantially.
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| 765. |
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| 766. |
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| 767. |
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| 768. |
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| 769. |
- Persson, Ylva, et al.
(författare)
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Use of a column leaching test to study the mobility of chlorinated HOCs from a contaminated soil and the distribution of compounds between soluble and colloid phases
- 2008
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 71:6, s. 1035-1042
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Tidskriftsartikel (refereegranskat)abstract
- An equilibrium and recirculation column test for hydrophobic organic chemicals (ER-H test) was used to study the leaching behaviour of chlorophenols (CPs), polychlorinated diphenyl ethers (PCDEs), polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) from contaminated soil. A 50% increase in the pore water velocity was shown to have little or no effect on the mobility of CPs, PCDEs, PCDFs and PCDDs. The standard deviations of truly dissolved compounds, CPs, were between 19% and 65% between the tests. However, the repeatability of the ER-H test decreased with increases in the hydrophobicity of the studied compounds; the standard deviations for PCDEs, PCDFs and PCDDs ranged from 53% to 110%, 57% to 77% and 110% to 130%, respectively. The influence of colloids on the release of these compounds was also examined. Up to 30% of the CPs in the soil were leached, of which 1–3% were associated with colloids. The PCDEs, PCDFs and PCDDs were found to be preferably associated with the particulate fraction of the leachate, and less than 0.2% of these compounds were mobilised.
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| 770. |
- Petrov, Vladislav, et al.
(författare)
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Estimation of wheel-rail friction for vehicle certification
- 2013
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 52:8, s. 1099-1114
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In certification of new rail vehicles with respect to running characteristics, a wide variety of operating conditions needs to be considered. However, in associated test runs the wheel-rail friction condition is difficult to handle because the friction coefficient needs to be fairly high and the friction is also generally hard to assess. This is an issue that has been studied in the European project DynoTRAIN and part of the results is presented in this paper. More specifically, an algorithm, based on vehicle dynamics simulations, for estimating the wheel-rail friction coefficient at vehicle certification tests is proposed. A quality measure of the estimation is also suggested.
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