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- 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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| 2. |
- 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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