Polybrominated Flame Retardants Research Articles

Influence of brominated flame retardant thermal decomposition products on HALS

Brominated flame retardants may undergo thermal decomposition at temperatures lower than those of polymer combustion. Decabromodiphenyl ether, which was the main subject of this study, exhibits a threshold decomposition temperature that is close to polypropylene processing temperatures. In the presence of hydrocarbon polymer the loss of bromine leads to the formation of lower brominated by-products and hydrobromic acid. The latter attacks stabiliser package components, HALS in particular. The aminium hydrobromide salt thus formed is well known to be inefficient as a stabiliser. Moreover, it has been found in this work that it is less thermally stable than the parent amine. In the case of polypropylene it has been demonstrated that excessive processing temperature of polymer containing polybrominated aromatic flame retardant and HALS results in an irreversible loss of the light stabiliser from the very beginning of material service life.

Hapten Syntheses and Antibody Generation for the Development of a Polybrominated Flame Retardant ELISA

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants that are increasingly an environmental concern. Several antibodies were developed for the polybrominated diphenyl ether flame retardant BDE-47 (1), often found in the highest concentration in human milk, plasma, and adipose tissue. Four haptens with different bromine and linker substitution patterns were synthesized and utilized to generate five polyclonal antibodies from goats and two polyclonal antibodies from rabbits. Competition was assessed using four different coating antigens for all seven antibodies. The coating antigen showed marked effects on competition. When the same hapten was used for antibody and the coating antigen less competition was observed. The effect of BDE structure on competition was evaluated by using BDE-47 (1), BDE-99 (2), BDE-100 (3), BDE-153 (4), and BDE-183 (5). None of the compounds showed high competition with antibody I-KLH, presumably because steric hindrance prevented formation of an efficient binding site. As predicted from structural considerations, BDE-47 (1) competed well with the remaining antibodies, whereas BDE-100 (3) competed well with only II-KLH. The remaining congeners (BDE-99 (2), BDE-153 (4), and BDE-183 (5)) contain bromines that cannot be positioned in binding sites and thus cross-react poorly. The competition study demonstrated that a bromine substitution on the congener could occupy a position analogous to the linker's position.

Hazard warning! [Restriction of the Use of Certain Hazardous Substances (RoHS) Directive

The manufacturing sector must now juggle with the potentially commercially limiting Restriction of the Use of Certain Hazardous Substances (RoHS) Directive. RoHS looks at the design and manufacturing phase of the product lifecycle. On the surface it is straightforward, requiring companies to restrict six highly toxic substances: lead, cadmium, mercury, chromium and two polybrominated flame retardants. The author explains how the ramifications of RoHS could be far wider reaching than the WEEE (Waste Electrical and Electronic Equipment) directive, and, if handled incorrectly, much more commercially damaging to manufacturing companies.

Ultrastructural changes observed in rat ovaries following in utero and lactational exposure to low doses of a polybrominated flame retardant

Polybrominated diphenyl ethers (PBDEs), used as flame retardants in textiles, plastics and electrical appliances, have been shown to interfere with thyroid homeostasis. We evaluated the effects of environmentally relevant concentrations (low doses) of 2,2′,4, 4′,5-pentabromodiphenyl ether (PBDE-99) on the female reproductive system. A single dose of either 60 μg or 300 μg PBDE-99/kg body weight (BW) was administered on gestation day 6 to gravid Wistar rats. A reference control was treated with 6- n-propyl-2-thiouracil (PTU) on gestation days 7–21. Ultrastructural changes compatible with altered mitochondrial morphology were observed in the ovaries of the F1 offspring. No statistically significant changes in ovarian follicle counts were observed. Mating of the F1 females with untreated males revealed resorption rates in the PBDE groups greater than the limits considered normal for our controls. External and skeletal anomalies were detected in offspring (F2) from two different dams (F1) with early developmental exposure to 300 μg PBDE-99/kg BW. Exposure to PBDE-99 resulted in female reproductive tract changes in the F1 generation which were apparent at adulthood.

Trends in fluctuating asymmetry in East Greenland polar bears ( Ursus maritimus) from 1892 to 2002 in relation to organohalogen pollution

Fluctuating asymmetry (FA) was studied in skulls of 283 polar bears ( Ursus maritimus) sampled in East Greenland from 1892 to 2002. Fourteen metric bilateral traits in skull and lower jaw were measured and compared between polar bears born until 1960 ( n=94) and from 1961 ( n=189). The period 1892–1960 was chosen to represent a period prior to appearance of organohalogens (polychlorinatedbiphenyls [PCBs], dichlorodiphenyltrichloroethanes [DDTs], hexacyclohexanes [HCHs], chlordanes [CHLs], hexachlorobenzene [HCB], polybrominateddiphenylethers [PBDEs] and dieldrin) originating from long-range transport to East Greenland from southern latitudes. The period 1961–2002 represents the period when polar bears have been exposed to organohalogens. During this latter period, the level of organochlorines is believed to have increased from 1960 to the late 1980s followed by a likely decrease from 1990 to 2002. Within this later period, other compounds such as, e.g., polybrominated flame retardants are believed to have increased throughout the period. Two different analysis showed, that the degree of fluctuating asymmetry did not differ statistically between the two periods in ten of thirteen traits (one trait excluded due to high measurement error). In fact, when significant differences were found in four of the traits, the fluctuating asymmetry was lower in skulls sampled after 1960. The degree of fluctuating asymmetry was higher in adults than in subadults for 6 of the 14 traits, whereas a higher degree of fluctuating asymmetry was found for only one trait in one of the analyses for subadults relative to adults. Females had a higher degree of fluctuating asymmetry than males in one trait. A time trend analysis did find fluctuations over time for five traits but the relationship was weak as the trend appeared to occur by chance due to the high number of regressions analysed ( n=42). A correlation analysis of FA versus the sum concentrations of various classes of organohalogens in adipose tissue from a subsample of 94 recently collected polar bears (1999–2002) did not show a trend either. Hence, the present study could not document a relationship between skull asymmetry in polar bears and periods with different exposure to organohalogens. These findings are possibly influenced by nutritional status, genetic factors, a subeffect exposure of organohalogens or confounded by other environmental factors (e.g. temperature) within the two investigated periods.

Analytical Methods for the Determination of Alkylphenolic Surfactants and Polybrominated Diphenyl Ethers in Wastewaters and Sewage Sludges. II Method Development

Analytical methods for the determination of two groups of compounds, the non-polar alkyl phenols along with their more polar ethoxylates, and the hydrophobic polybrominated flame retardants in wastewater samples have been developed. The methods allow for determination of the analytes in both the aqueous and solid phases, which were separated by centrifugation and filtration. Extraction from the aqueous phase involved the use of SPE for the surfactants, however, liquid-liquid extraction was found to be more efficient for the PBDE. Alkyl phenols and their ethoxylates were extracted from the solid phase by shaking with solvent and Soxhlet was used for extraction of PBDE. Sample cleanup was based on alumina columns for the PBDE and surfactants when extracted form solids. Quantification of surfactants utilised LC-MS with ESI in both positive and negative ionisation mode, and GC-MS (NCI) was used to determine the PBDE, with the exception of the deca congener, where a 10 m column installed on GC-ECD resulted in short run times and reduced thermal decomposition. Method recoveries for the surfactants were above 80%, and for PBDE 92±5% from the solid phase and 95±5% from the liquid phase.

Endocrine active industrial chemicals: Release and occurrence in the environment

Of the xenobiotic endocrine active substances (EASs), tributyltin (TBT) has had the clearest link to an impact on aquatic ecology. Its release from marine antifouling paints had a drastic impact on dogwhelk populations in polluted harbors due to a masculization effect. 4-tert-nonylphenol is seen as the most significant of the industrial xenobiotic estrogen mimics, being implicated as the dominant endocrine disruptor in certain industrialized river reaches. Apart from hot spots associated with particular industries, the estrogenic alkylphenols, phthalates, and bisphenol A are present in effluent and receiving water at concentrations below that which would give cause for concern. Other more bioaccumulative compounds such as polybrominated flame retardants, dioxins, furans may possess some endocrine active properties. The possibility of additivity effects may yet mean that low concentrations of xenobiotic EASs will need careful consideration. It is noted that considerable quantities of many of these compounds are often found in sewage sludge and sediments.

The flame retardants tetrabromobisphenol A and tetrabromobisphenol A–bisallylether suppress the induction of interleukin-2 receptor α chain (CD25) in murine splenocytes

Polybrominated flame retardants (PBF) are frequently used additives in electronical equipment. They are ubiquitous environmental contaminants which bioaccumulate with several health effects for humans and the environment. This study investigated immunotoxic effects of the PBF tetrabromobisphenol A (TBBP A), tetrabromobisphenol A-bisallylether (TBBP A-AE), tetrabromobisphenol A-bis-(2,3-dibromopropyl-ether) (TBBP A-PE), decabromodiphenylether (DBDE), and 2,4,6-tribromophenol (TBP) in vitro . The structurally related polychlorinated aromatic hydrocarbon 3,4,3′,4′-tetrachlorobiphenyl (PCB77) and dioxins mediate their immunotoxicity via the Ah-receptor gene complex. A highly relevant function of the Ah receptor, the induction of CYP 1A1 in hepatocytes of C57BL/6 mice by the established inducers 3-methylcholanthrene (MC) and PCB77 was compared to the effect of PBF by measurement of ethoxyresorufin- o-deethylase (EROD) activity. The PBF did not show any induction of CYP 1A1, while EROD activity of hepatocytes exposed to MC and PCB77 was induced 10.8- and 8.7-fold, respectively. To investigate immunotoxic effects of the flame retardants, splenocytes of C57BL/6 mice were incubated with subtoxic doses of the flame retardants and PCB77 and activated by concanavalin A (Con A). The flame retardants TBBP A and TBBP A-AE significantly inhibited the expression of interleukin-2 receptor α chain (CD25) in contrast to TBBP A-PE, DBDE, TBP, and PCB77 as shown by immunohistochemistry and quantitative analysis by laser scanning cytometry. None of the substances had any effect on the Con A-induced production of cytokines. Hence, TBBP A and TBBP A-AE may act as immunotoxic compounds by specifically inhibiting the expression of CD25.

Contaminants in Svalbard polar bear samples archived since 1967 and possible population level effects

Blood plasma samples were collected in 1967 from 32 polar bears ( Ursus maritimus) in eastern Svalbard. These samples were stored frozen until 2001 and then analyzed for 33 polychlorinated biphenyls (PCB), two toxaphene congeners, DDTs, chlordanes (CHL), hexachlorobenzene, hexachlorocyclohexanes (HCHs), and polybrominated flame retardants (biphenyls and diphenyl ethers). The 1967 pollutant levels were compared with values from 1993 to 1994 for adult females and adult males to obtain insights into the historical development of pollution in the Norwegian Arctic. Differences in the OC levels measured between 1967 and 1993–1994 ranged from a decrease (PCB 187 and p, p-DDE) to unchanged in both sexes (PCBs 105, 118, 209, and HCH) to an increase in females (PCBs 99, 128, and CHL), to increases in both sexes (PCBs 138, 153, 156, 157, 170, 180, 194, and 206). The maximum change was a nine-fold increase in PCB 157 in adult females. Changes from 1967 to 1993–1994 in contaminant pattern expressed relative to PCB 153 could be explained by a combination of selective metabolism and accumulation of organochlorines in polar bears and temporal changes in the contaminant mixture being transported to the Arctic. Harvest of polar bears in Svalbard ended in 1973 and it appears that most pollutant levels were increasing at the same time that the population was expected to recover from over-harvest. The mean age of adult females in the Svalbard population was similar to other populations where pollution levels are lower but harvest is intense. Females with cubs-of-the-year ⩾16 years old are uncommon in the population for unknown reasons. The impacts of contaminants on the Svalbard polar bear population are inconclusive but there are suggestions of contaminant-related population level effects that could have resulted from reproductive impairment of females, lower survival rates of cubs, or increased mortality of reproductive females.

Thermal formation of PBDD/F from tetrabromobisphenol A––a comparison of polymer linked TBBP A with its additive incorporation in thermoplastics

For a long period, polybrominated flame retardants are under discussion because of the formation of polybrominated dibenzo- p-dioxins (PBDD)/dibenzofurans (PBDF) (PBDD/F) in case of thermal stress. Concerning polymer linked tetrabromobisphenol A (TBBP A), formation of PBDD/F was commonly presumed to be sterically hindered because of the covalent fixation into the polymer backbone. Combustion experiments with additively incorporated TBBP A compared with its polymer linkage revealed, that this assumption is incorrect and has to be revised. Under same conditions, similar PBDD/F concentrations in the range of 17.5–19.6 mg PBBD/F per kg TBBP A applied were analyzed. PBDD/F homologue distribution patterns were almost identical predominated by low brominated PBDF. These findings for PBDD/F formation have to be considered in future discussions regarding thermal stress caused by combustion or recycling processes, including other flame retardants bound in polymer matrix, e.g. polybrominated polystyrene (PS), or those with molecular structures showing less analogy to PBDD/F, like hexabromocyclododecane. The second aspect introduced, is the influence of different plastics on the formation rates of PBDD/F. In this context, combustion experiments were performed in an atmosphere consisting of synthetic air and HBr. PBDD/F concentrations were 8.47 mg/kg polyethylene, 1.67 mg/kg PS, 3.92 mg/kg phenolic resin and 18.1 mg/kg epoxy resin. Distribution patterns of PBDD/F homologues could partly be correlated with the occurrence of the precursors polybrominated benzenes and phenols.

Behavior of bromine on the thermal decomposition of paper-based phenolic laminate wastes

We investigated the thermal properties and behavior of bromine on the thermal decomposition of paper-based phenolic laminate wastes containing polybrominated flame retardants. The thermal properties of the phenolic laminate wastes were measured with a thermogravimeter and a conduction-type scanning calorimeter (TG-CSC). The weight loss of the wastes on thermal decomposition was mainly in three phases between 40°C and 600°C. The enthalpy (ΔH) of the thermal decomposition was 104 cal/g. The material balance of the decomposition components was measured with batch-type thermal decomposition equipment. The ratios of carbon residue, liquid, and gas on decomposition at 800°C in a vacuum were 37 wt. %, 48 wt. %, and 15 wt. %, respectively. The bromine contents in the carbon residue and liquid were less than 0.02 wt. % and 10 wt. %, respectively. These results are useful both in the carbonization process of these wastes and in the application of carbon residue as carbon materials.

Cathode ray tube recycling

Lead and polybrominated flame retardants are the two hazardous materials that can be found in electronic appliances. Particularly, cathode ray tubes (CRT) contain leaded glasses. In a computer monitor, over 98% of the lead is in the CRT. This material is generally not accepted for reuse as a component; only those from televisions can be reused. However, this currently represents only a very small market. Envirocycle (a US company) has developed a process to recycle all glasses contained in CRTs; this process includes cleaning and sorting glass. The product obtained is used for the manufacture of new CRT glass. Some industries have used pulverized glass from CRTs in smelting processes as slagging material instead of sand or slag. In this paper, some environmental issues related to the recycling of computers and television sets, and CRTs from computers are presented and discussed. Different processes used to recycle CRTs are described along with an economic analysis.

Computer monitor recycling: a case study

The total number of computer monitors being scrapped per year worldwide is predicted to rise to 30 million units by the year 2005. Monitors contain significant quantities of lead (in the solder and CRT glass) and polybrominated flame retardants, which are potentially hazardous if released to the environment. A recent study investigated the possibility of cost-effectively recycling monitors.

Interaction between polybrominated flame retardants and high impact polystyrene

Mixtures of two crystalline brominated aromatic flame retardants with a surrounding polymer were studied by differential scanning calorimetry, dynamic mechanical analysis (DMA), wide angle X-ray scattering, and solid-state NMR spectroscopy. 1,2-Bis(tet-rabromophthalimide)ethane (I) and decabromodiphenyloxide (II) were evaluated in high impact polystyrene (HIPS). Additive I exhibits all the properties of an inert filler. The crystalline structure with respect to the pure material remains unchanged within the polymer. Concerning the HIPS matrix, a slight rise in the melt viscosity and a reduced impact strength as compared to the base resin was observed. In contrast, additive II is miscible with the HIPS matrix and dissolves completely. This leads to an increase of the glass transition temperature of the polybutadiene phase as revealed by solid-state NMR spectroscopy and DMA. The impact resistance of the HIPS matrix is less affected by additive II than by additive I. No interactions were noted with the PS phase at temperatures up to the glass transition.

High-temperature degradation of polybrominated flame retardant materials

This experimental study examined gas-phase oxidative and pyrolytic thermal degradation of three brominated flame retardant materials in a high-temperature flow reactor. Br-benzenes, Br-phenols, PBDDs and PBDFs were formed at intermediate temperatures and subsequently destroyed by 800°C.

Effects of feeding a polybrominated biphenyl flame retardant (firemaster bp-6) to male rats

Effects of Feeding a Polybrominated Biphenyl Flame Retardant (fireMaster BP-6) to Maie Rats Susan J. Harris 1, Helene C. Cecil 2, and Joel Bitman 1 lu.s. Department of Agriculture, Agricultural Research Service, Animal Physiology and Genetics Institute, Beltsville, Md. 20705, 2Send correspondence to" U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, APGI, Avian Physiology Laboratory, Building 262, Beltsville, Md. 20705