Brominated dioxins

Pyrolysis of FireMaster BP-6 in the temperature range of 600 900 °C in the absence of oxygen produced bromobenzenes and brominated biphenyls as key products, but no brominated dioxins and dibenzofurans (Thoma and Hutzinger 1987 Thoma et al. 1987). Thermolysis of Hi re Mast a- BP-6 between 400 and 600 °C in the presence of air produced 23,7,8-tetrabromodibenzofuran in the percent ( 1 %10 g/kg) range (Rappe and Buser 1980). Pyrolysis of FireMaster BP-6 in an open quartz tube at 800 °C produced 0.48 1.49 gZkg2,3,7,8-TCDD equivalent levels of polybrominated dibenzofurans (Zacharewski et al. 

Ott MG, Zober A. 1996. Morbidity study of extruder personnel with potential exposure to brominated dioxins and furans. IE Results of clinical laboratory studies. Occup Environ Med 53(12) 844-846. 

Zober A, Ott MG. 1997. Digestive tract neoplasma among employees with past exposure to brominated dioxins. Occup Environ Med 54(1) 66. 

Fig. 3.33 Dysidea dendyi, an Australian sponge that contains the brominated dioxins, spongia-dioxins A-C and related methyl ethers (2235-2239) (Photo N. Utkina)...

Schecter A, Ryan JJ, Masuda Y, et al. 1994c. Chlorinated and brominated dioxins and dibenzofurans in human tissue following exposure. Environ Health Perspect 102(S1) 134-147. 

Recycling of plastics is difficult, because of the content of the additives PBBs and PBDEs [27]. Pyrolysis of flame retardant material of printed circuit board and electronics components (laboratory scale) produces high amounts of brominated dioxins and furans (2,3,7,8-TeBDF, 29 pg/kg residue after quarts flask pyrolysis in N2/H2 atomosphere at 1100 °C) located in the condensed material. It was known that these plastics contain flame retardants to a maximum of 20 wt%. PBDEs can be extracted from plastics based on propyl-carbonate. The origin of brominated dioxins and furans detectable in propyl-carbonate extract is still to be investigated. Further recycling activities which process flame retarded plastics might produce hazardous products, an aspect that has to be investigated more closely [27]. 

Eormation of brominated dioxins and furans on combustion of PBDE containing products may be a hazard. 

For example, on the potential for forming brominated dioxins and furans from incineration of brominated compounds see US Environmental Protection Agency, Environmental Profiles of Chemical Flame-Retardant Alternatives for Low-Density Polyurethane Foam, 2005, http //www.epa.gov/dfe/pubs/flameret/ffr-alt.htm. 

Furthermore, brominated dioxin, as well as mixed brominated-chlorinated dioxin, data are needed in order to determine their environmental impact. However, chemical analysis of mixed halogenated dioxins is very difficult due to the large number of possible combinations (there are 4,600 potential mixed congeners). In order to achieve this goal it is necessary to develop analytical procedures that permit determination of different groups of brominated contaminants. 

FR-1808 has undergone extensive toxicological and environmental testing. The tests have shown very low acute and repeated dose toxicity. In addition, the Fresenius Institute performed analyses on both the neat product and on gases evolved when simulating conditions in a municipal incinerator. The results indicate that FR-1808 poses no risk through any release of brominated dioxin or furan species. 

Both chlorinated and brominated dioxins are emitted in greater quantities from non-FR TVs with just a Horizontal Bum (HB) rating compared to the TVs containing brominated flame-retardants to a VO rating level. Polycyclic aromatic hydrocarbons (PAH) are also given off in far greater quantities by the non-FR TVs than the protected ones. 

Formation of dioxins/furans A compound containing standard loadings of decaBDPE was injection moulded and reground to simulate recycling. After five cycles the material was analysed for brominated dioxins and fiirans. The compound showed no detectable amounts and the recycled forms showed levels below the limit of the German Dioxin Decree by a factor of about 40. 

Bromine was expected to promote volatility of metals, since metal bromides tend to have low boiling points. This was indeed observed as metal transfer to the fly ash increased for copper, lead, zinc and others present in the generality of the MSW. There was no significant correlation between increased bromine levels and the overall level of halogenated dioxins and furans and the brominated dioxins and furans that were present were almost totally destroyed or removed. Bromine can be recovered from various species that reach the gas phase. 

The Dutch Ministry of the Environment (VROM) in particular has long been concerned about PBBs and PBBOs and has considered introducing its own legislation, strongly opposed by the Dutch Plastics Federation (NFK) and against evidence by the Dutch National Institute for the Environment (RIVM) that studies of municipal waste incineration did not show any relation between bromine content of disposed waste and formation of brominated dioxins. 

Pressures to introduce restrictive legislation in Europe have eased as the debate has moved from the political arena to focus on assessment and management of risk. The main health and environment issue centres on halogen-based FRs, for possible formation of dioxin-related products such as brominated dioxins/furans by polybrominated biphenyl ethers (PBBE) under combustion conditions. These are very effective flame retardants and are widely used in polystyrene, polyethylene and polypropylene. Only a few of 75 identified brominated dioxin ionomers and 135 brominated furan ionomers are toxic, and they are only present in low concentrations in combustion. Less-toxic furans tend to be formed more than dioxins, and brominated dioxine/furans are less toxic than their chlorinated counterparts. 

In 1994 the German Chemicals Banning (Dioxin) Ordinance was extended to include brominated dioxins/furans as well as chlorinated dioxins/furans. Certain tetra and penta-BDDs and BFDs were restricted (up to 10 ppb to July 1999 and 1 ppb thereafter) and higher limits (up to 60 ppb to July 1999 and 5 ppb thereafter) were imposed on total levels of specified hexa-, penta-, and tetra-BDDs and BDFs. 

In 1985-86, a German study detected brominated dioxins and furans from laboratory pyrolysis at 510-630 C of a brominated diphenyl oxide. The relevance of these pyrolysis studies to the real hazard presented by these flame retardants under actual conditions of use has been questioned. 

For the first time, 2,3,7, 8 - brominated dioxins and furans are restricted now as well 8 PBDC/PBCF-congeners were added to this list for regulation. This was the result of an approximation process to the scientific progress concerning the appearance, environmental fate, toxicity and analytical methodology of these substances. 

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