| 1. |
- Björn (Fredriksson), Annika, et al.
(författare)
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Impacts of Temperature on the Leaching of Organotin Compounds From Poly(vinyl chloride) Plastics : A Study Conducted Under Simulated Landfill Conditions
- 2007
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Ingår i: Journal of Vinyl and Additive Technology. - : Wiley. - 1083-5601 .- 1548-0585 .- 0193-7197 .- 1548-0577. ; 13:4, s. 176-188
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to investigate whether organotin-stabilized poly(vinyl chloride) (PVC) products could contribute to the pool of organotins observed in landfill leachates, and if the possible release could be related to different temperatures and landfill degradation phases. Small-scale anaerobic reactors filled with generic household waste, a mixture of inocula, and different PVC plastics were used in the study and incubated at 20, 37, 55, and 70°C. The reactor units incubated at temperatures of 20-55°C underwent the anaerobic degradation phases that are characteristic for the aging of landfilled waste material. There were, however, differences in the duration of the phases as well as in the total biogas production among the units. Under methanogenic conditions greater losses of organotin compounds were observed as compared to acidogenic conditions. It was shown that the release of organotin stabilizers increases considerably at temperatures above the glass transition of the PVC products. A dealkylation from di- into monoalkyltin species was observed, as well as a possible methylation of inorganic tin. However, the main part of the organotins was adsorbed into the solid waste matrix.
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| 2. |
- Hörsing, Maritha, 1970-, et al.
(författare)
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Effects of Temperature and Landfill Ageing on leaching and Degradation of Phtalates from a Poly(vinyl chloride) Carpet under Simulated Landfill Conditions
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Phthalic ether esters are a group of chemicals used in the manufacture of PVC plastics, often as plasticizing additives, hence they may leach from the material and/or finished products before, during and after their use. This article presents results from laboratory-scale investigations of the fates of di-2-ethylhexyl phthalate (DEHP) and benzyl-butyl phthalate (BBP) under simulated landfill conditions, in custom-designed incubation units filled with model municipal solid waste. More specifically, the effects of temperature and landfill degradation phase on both the leaching and degradation potential of the two phthalates from a PVC carpet were examined, by measuring them in samples from units maintained at 20, 37, 55 and 70°C as they progressed through anaerobic acidogenic and methanogenic landfill phases. The results show that both BBP and DEHP leached from the carpet. For DEHP there was a clear temperature effect, and the highest losses were observed at 70°C, while for BBP slight increases in losses with temperature were observed from 20 to 55°C, and from 55 to 70°C, but the largest losses were seen at 37°C, probably due to biodegradation. Further degradation of the leached phthalates occured at all temperatures. Apparent degradation products observed included phthalic acid (PA) and mono (2-ethylhexyl)-, monobutyl- and monobenzyl-phthalate. In all cases the biological degradation of the phthalates occurred mainly after the systems switched to methanogenic conditions. The rate-limiting step of degradation in the 20 and 37°C units seemed to be the transformation of the monoesters, which tended to accumulate more than PA, while at 55 and 70°C PA accumulated to a higher extent.
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| 3. |
- Hörsing, Maritha, 1970-, et al.
(författare)
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Investigation of the transformation potential of some ether derivatives of tetrabromobisphenol A and dimethyl ether of bisphenol A under methanogenic conditions
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This study focused on transformation of the flame retardant tetrabromobisphenol A (TBBPA) and ether derivatives thereof during incubation under methanogenic conditions using landfill waste as inoculum. Bisphenol A dimethyl ether was also investigated in that context. Glass wool was placed in the incubation flasks to increase the surface area for adsorption of target compounds and thereby maximize exposure to the microbial population. A uniform analytical protocol for extraction of the silica surface and the aqueous phase was developed to suit all the targets. Overall recoveries were lowest for the dimethylated ethers and highest for TBBPA-dihydroxyethylether. TBBPA decreased to below detection limit within 35 days, but neither BPA nor the methyl ether of TBBPA was confirmed as a transformation product. The dimethylated ethers of BPA and TBBPA disappeared within 14 and 51 days, respectively, and BPA, but not TBBPA, proved to be a transformation product. No losses were observed for the most hydrophobic target TBBPA-dibromopropyl ether during the time frame of the transformation study (i.e., 51 days).
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| 4. |
- Hörsing, Maritha, 1970-
(författare)
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Leaching and Transformation of Flame Retardants and Plasticizers under Simulated Landfill Conditions
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Many products used in our everyday life contain chemicals added to give them specific properties. Flame retardants (FRs) are added to prevent or retard fires in textiles, plastics etc., while plasticizers are supplied to make plastics more flexible. Through their widespread applications chemicals from both groups are emitted and spread in the environment during usage and disposal. For a long time these products were mainly disposed of in landfills, and in many areas they still are. Thus, since some of these chemicals also pose potential environmental risks and health hazards, there is a need to elucidate their fates during exposure to the landfill environmentThe objectives of this thesis were to investigate the leaching and transformation of FRs and plasticizers from products in which they are used under simulated landfill conditions. To assess the importance of changes in these processes as landfills progress through recognised ageing phases (accompanied by large transitions in both physico-chemical and biological conditions) it was desirable to simulate the changes that typically occur in landfills within a short time period, of 1-2 years.. This was achieved using the newly developed intermediate-scale (3 litre) Modular Environmental Test System (METS).The METS were employed in two studies. The first was an investigation of the leaching and degradation of plasticizers from PVC carpet material incubated at different temperatures (20, 37, 55 and 70°C) prevailing in landfills. Plasticizers subjected to this investigation were the phthalates di-2-ethylhexyl phthalate (DEHP) and benzyl-butyl phthalate (BBP), both of which were found to leach from the carpet. The leaching of DEHP and BBP generally increased with increases in the incubation temperature. However, the most rapid leaching of BBP occurred at 37°C, probably due to high microbial activity at this temperature. Both DEHP and BBP were shown to be degraded within the landfill environment and the degradation potential was highest during the methanogenic landfill phase. In the second METS study the leaching of FRs used in both reactive and additive applications (i.e. chemically bonded to and merely blended with the material, respectively) was characterised. The epoxy oligomer tetrabromobishpenol A (TBBPA) and the phosphorus-based Pyrovatex FRs were selected as representatives for the reactive FRs, while the nitrogen-based melamine and phosphorus-based Proban FRs were selected to represent additive classes. During the incubations, which lasted more than two years, the leaching from melamine was shown to be affected by the landfill phase development. The leaching from the Pyrovatex-treated material and the TBBPA epoxy oligomer seemed to result almost entirely from the washout of unreacted manufacturing residuals. This was also probably true for the FR in the Proban-treated material, although it is durable (despite being additively applied) and thus seemed to leach more slowly (manifested as an increase in phosphate levels in the leachate towards the end of the monitoring period).Finally, due to the paucity of knowledge regarding the fate of ether derivatives of TBBPA (which are also used as FRs) an anaerobic degradation assay was performed. The method employed for this assay was a modified, small-scale ISO standard method. In order to evaluate the degradation assay a uniform analytical protocol was developed. The degradation survey showed that losses of TBBPA, TBBPA-dimethyl ether and bisphenol A dimethyl ether occurred, but no losses of the most hydrophobic compound, TBBPA-dibromopropyl ether, were observed.
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| 5. |
- Hörsing, Maritha, 1970-, et al.
(författare)
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Leaching of Flame Retardants from products deposited in Landfills
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Materials in many products in daily use are amended with chemicals to give them desired properties, e.g. flame retardants (FRs) used to reduce the risks of products catching fire. However, potential risks posed by some of these chemicals, including FRs, to the environment and human health have raised concerns. Hence, there is a need for more knowledge regarding the fate of FRs, notably in landfills, where many FR-containing products are deposited. This article presents analyses of FRs and derivatives in leachates sampled during laboratory-scale simulations of landfills containing various FR-containing products progressing through typical landfill ageing phases. The FRs represented substances used both reactively, i.e. bound to the flame-protected material and additively, i.e. without any covalent bonding to the product.The phosphorus-based Pyrovatex-FR and the brominated tetrabromobisphenol A (TBBPA) were used to represent the reactive FRs, and the nitrogen-based melamine and phosphorus-based FR of Proban the additive FRs. Residual FRs from the treatment of the materials were probably the main contributors to the leachates from all products. Their durability, i.e. ability to withstand laundry washes, was reflected in their leaching abilities, while the different landfill conditions were of minor importance, except for melamine (of which approximately 10% of the amount present in the test product leached and mineralised to carbon dioxide and ammonia, mainly during the period when the landfill models passed from acidogenic to methanogenic conditions). The other additively applied FR in Proban leached first during the later part of the incubation (between 80 and 112 weeks), in accordance with its laundry resistance. Substantial proportions of the residual chemicals in Pyrovatex-treated materials are generally lost during the first washing. Accordingly, early losses of the chemicals used in this treatment were detected during the landfill simulation. Elevated phosphate concentrations were also detected in simulations with the Pyrovatex- and Proban-treated products, suggesting that the FRs generated in these treatments were degraded during or after release to the leachate. Small amounts of TBBPA were observed at the end of the incubation, and no TBBPA degradation products were observed, but debromination (which is likely to occur during anoxic stages) would lead to the formation of bisphenol A.
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| 6. |
- Jonsson, Susanne, 1965-, et al.
(författare)
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Investigation of sorption phenomena by solid-phase extraction and liquid chromatography for determination of some ether derivatives of tetrabromobisphenol A
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Observed sorption and chromatographic behaviour served as a starting point for examination of four ether derivatives of the flame retardant tetrabromobisphenol (TBBPA). To date, there is little or no information about these compounds in the scientific literature. The targets in the present study had calculated log Kow values of 6.0–10, indicating a rather hydrophobic nature. A broad range of different types of solvents were used in order to elucidate the mechanisms of sorption on one hydrophilic surface (silica) and two hydrophobic surfaces (polystyrene divinylbenzene polymers). Also, three chromatographic columns (C18, C8, and dual C18-based) were evaluated. In general, the most hydrophilic and the most hydrophobic derivatives (dihydroxyethyl- and di(2,3-bromopropyl), respectively) were more easily desorbed from the studied surfaces by the selected solvents.Regardless of the experimental test conditions applied, the lowest recovery was seen for dimethoxy-TBBPA, followed by TBBPA itself. Also, this study claims that the polar character of the dual-phase column was not as pronounced as asserted by the manufacturer.
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