Polybrominated diphenyl ethers chemicals

Fig. 7 Generic chemical structures of polyhalogenated compounds. X=C1, Br. (I) Polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs) (II) chlorophenols (CPs), bromophenols (BPs) (III) polychlorinated diphenyl ethers (PCDE), polybrominated diphenyl ethers (PBDE) (IV) polychlorinated dibenzo-p-dioxin (PCDD), polybrominated dibenzo-p-dioxin (PBDD) (V) polychlorinated dibenzofuran (PCDF), polybrominated dibenzofuran (PBDF) (VI) tetrabromobisphenol A (TBBPA)...

The replacement of established chemistries with newer ones is one of the classic drivers of change in the chemical industry. One of the current hotbeds of this kind of change is the replacement of brominated flame retardants in polymer formulations. The brominated flame retardants under the most scrutiny have been polybrominated diphenyl ethers, particularly penta- and octabromodiphenyl ether, which have been shown to be persistent in the environment and to bioaccumulate. Great Lakes Chemical is voluntarily phasing out penta- and octa-BDEs by the end of next year. The phaseout is made possible by the clean bill of health granted by EPA for Firemaster 550, a replacement for penta-BDE in flexible PU applications. BRG Townsend claims the phaseout of penta-BDE and octa-BDE is not as earth shattering as would be an exit from deca-BDE, a styrenics additive that is produced in the highest volume of the PBDEs. 

It is briefly reported that flame retardants were among the chemicals discovered in the blood of Margot Wallstrom, European Commissioner for the Environment. Wallstrom submitted a sample for testing to illustrate the presence of persistent chemicals in the human body. The Department of Environmental Sciences at Lancaster University tested for the presence of 77 man-made chemicals. The laboratory discovered 28 chemicals in Wallstrom s blood, including polybrominated diphenyl ethers, commonly used as flame retardants. 

Fig. 4.6 Chemical structures of (a) tetrabromobisphenol A (TBBPA), (b) hexabromocyclodo-decane (HBCD), and (c) polybrominated diphenyl ethers (PBDEs)...

Fig. 16.19 GC-ECD chromatograms showing appearance of polybrominated diphenyl ether (PBDE) congeners, after sunlight irradiation of BDE-209 (retention time = 88.7 min) adsorbed on montmorillonite, at different times. Reprinted with permission from Ahn MY, Filley TR, Jafvert CT, Nies L, Hua I, Bezares-Cruz J (2006) Photodegradation of decabromodiphenyl ether adsorbed onto clay minerals, metal oxides, and sediment. Environ. Sci. Technol. 40 215-220. Copyright 2006. American Chemical Society...

The POCs include, but are certainly not limited to the polychlorinated biphenyls (PCBs) and the organochlorine pesticides, including those in current use, restricted use and historic use brominated flame retardants including polybrominated diphenyl ethers PAHs and the sometimes more toxic transformation products of these chemicals. Table 1 summarizes information on some of the POCs more commonly detected in alpine environments. 

The chemicals tested were either organochlorine pesticides, polychlorinated biphenyls (PCBs) or polybrominated diphenyl ethers (PBDEs) (the latter are used as flame retardants) (www.wwf.org.uk/chemicals, accessed November 2006). 

Polybrominated Diphenyl Ethers. No specific infonnation was located regarding interactions between PBDEs and other chemicals. PBDEs are inducers of hepatic microsomal enzymes (Carlson 1980a, 1980b Fowles et al. 1994 Hallgren et al. 2001 Zhou et al. 2001, 2002) and therefore could potentially enhance or decrease the toxicity of any substance that is metabolized by the P-450 system. 

Polybrominated Diphenyl Ethers. Information on the reproductive toxicity of PBDEs is limited to a single one-generation oral study of decaBDE in rats that found no exposure-related functional effects (Dow Chemical Co. 1975 Norris et al. 1975a, 1975b). Tests of octaBDE and/or pentaBDE, particularly second-... 

Polybrominated Diphenyl Ethers. Oral developmental toxicity studies have shown no evidence of teratogenicity of deca-, octa-, and pentaBDE in rats and rabbits, although fetotoxic effects, including skeletal ossification variations at maternally toxic doses, have occurred (Argus Research Laboratories 1985b Breslin et al. 1989 Dow Chemical Co. 1975, 1985 Life Science Research Israel Ltd. 1987 Norris... 

Polybrominated Diphenyl Ethers. Biomaikers that could be used to characterize health effects caused specifically by PBDEs have not been identified. The thyroid is a critical target for PBDEs in animals, as discussed in Section 3.2.2.2, Endocrine Effects, and serum T4 is a potential biomarker of effect for these chemicals in humans. Although this biomarker is not specific to PBDEs because other antithyroid agents can have similar effects, changes in T4 could be considered to indicate potential impairment of health. 

Polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) are each classes of structurally similar brominated hydrocarbons. PBBs are a class of chemical compounds in which 2 10 bromine atoms are attached to the biphenyl molecule. PBDEs are a class of chemical confounds in which 2 10 bromine atoms are attached to the diphenyl ether molecule. Monobrominated structures (i.e., one bromine atom attached to the molecule) are often included when describing PBBs and PBDEs. The general chemical structures of PBBs and PBDEs are similar when viewed in one dimension, differing only in an ether linkage, as shown below ... 

Polybrominated Diphenyl Ethers. In the United States, Albemarle Corporation and Great Lakes Chemical Corporation market mixtures of PBDEs under trade names (e.g., Bromkal 70-5DE, DE-71, Tardex 50, Tardex 50 L, and Saytex 115 for pentaBDE mixtures DE-79, FR-1208, and Saytex 111 for octaBDE mixtures and DE 83, FR-300 BA, and Saytex 102 for decaBDE mixtures). The are also several trade names used by producers from Europe and Japan for the BDE mixtures. The chemical identities of commercial mixtures of pentaBDE, octaBDE, and decaBDE are listed in Table 4-3 (WHO 1994a). 

For consistency in this document, polybrominated diphenyl ethers or PBDEs will be used to identify this class of chemicals. The PBDE homologs are abbreviated as follows in this document ... 

Polybrominated Diphenyl Ethers. Information found in the literature regarding the physical and chemical properties of selected technical PBDE mixtures is presented in Table 4-6. 

Polybrominated Diphenyl Ethers. PBDEs are used as additive flame retardants in thermoplastics. Additive flame retardants are physically combined with the polymer material being treated rather than chemically combined (as in reactive flame retardants). This means that there is a possibility that the flame retardant may diffuse out of the treated material to some extent. 

Polybrominated Diphenyl Ethers. Many of the relevant physical and chemical properties of the PBDEs are not available (see Table 4-4). Very limited data are available on the physical and chemical properties for the individual congeners. Important data, such as vapor pressure, and Henry s law constant, are necessary for the prediction of the environmental fate and transport ofPBDEs. 

Polybrominated Diphenyl Ethers. No exposure registries for PBDEs were located. This substance is not currently one of the compounds for which a subregistry has been established in the National Exposure Registry. The substance will be considered in the future when chemical selection is made for subregistries to be established. The information that is amassed in the National Exposure Registry facilitates the epidemiological research needed to assess adverse health outcomes that may be related to exposure to this substance. 

ECD = electron capture detection GC = gas chromatography GPC = gel permeation chromatography HRMS = high resolution mass spectrometry LC = liquid chromatography MS = mass spectrometry NAA = neutron activation analysis NCI = negative chemical ionization PBDEs = polybrominated diphenyl ethers... 

La Guardia MJ, Hale RC, Harvey E, et al. 2000. Endocrine disruptors (octylphenol, nonylphenol, nonyl phenol ethoxylates and polybrominated diphenyl ethers) in land applied sewage sludge biosolids. In Preprints of extended abstracts. American Chemical Society, Division of Envrionmental Chemistry. 

A majority of U.S. biomonitoring efforts measure such analytes as heavy metals, pesticides, cotinine, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins, phthalates, and volatile organic compounds (VOCs). Future population-based studies (such as NHANES) will include such chemicals as perfluorinated compounds, polybrominated diphenyl ethers (PBDEs), and perchlorate, on which little exposure information is available. 

Apart from the POPs, other persistent organic chemicals such as butyl tin compounds (BTs) (Iwata et al., 1994 Tanabe et al., 1998b Tanabe et al., 2000 Sudaryanto et al., 2002), polybrominated diphenyl ethers (Ueno et al., 2004) and the compounds like tris(4-chloropheyl) methane (TCPMe) and tris(4-chlrorphenyl) methanol (TCPMOH), the chemicals... 

School is an important setting for many children and adolescents. Many of the residential factors described above can apply to the school setting. However, there may be additional sources of chemicals that are associated with laboratories, activity rooms, or school equipment. For example, exposure to volatile compounds has been reported in art buildings (Ryan et al., 2002) polybrominated diphenyl ethers, used in flame retardants, were detected in teaching halls containing 20 computers (Sjodin et al., 2001) mercury intoxication resulting from use of school barometers has been reported in a number of countries (Koyun et al., 2004) and in Mexico, lead levels were higher in children who habitually bite coloured pencils (Lopez-Carrillo etal., 1996). 

---