Polybrominated Biphenyls and Diphenyl Ethers

The structural range of industrially important representatives of these groups is enormous, and includes chlorobenzenes (solvents), polychlorinated biphenyls (PCBs) (hydraulic and insulating fluids), and polybrominated biphenyls and diphenyl ethers (flame retardants). There is widespread concern over both the persistence and the potential toxicity of all these compounds, and sites that have become contaminated during their production represent a threat both to the environment and to human health. Pathways for the aerobic bacterial degradation of chlorobenzenes and chlorobiphe-nyls, and their brominated analogs have been discussed in Chapter 9, Part 1. 

Pijnenburg AMCM, Everts JW.de Boer J, Boon JP (1995) Polybrominated biphenyl and diphenyl ether flame retardants analysis, toxicity, and environmental occurrence. In Ware GW (ed) Reviews of environmental contamination and toxicology, vol 141. Springer, Berlin Heidelberg New York, p 2... 

DeBoer J, DeBoer K,Boon JP (1999) Polybrominated biphenyls and diphenyl ethers. In Paasivirt J (ed) The handbook of environmental chemistry. Springer, Berlin Heidelberg... 

Highly brominated biphenyls and diphenyl ethers have been manufactured as flame-retardants, and the diphenyl ethers have apparently become environmental contaminants (references in Sellstrom et al. 1998 see also Chapter 3, Section 3.6.3). One of the reasons for concern is the formation of polybrominated dibenzofurans and dibenzo[-l,4]-dioxins (although not 2,3,7,8-tetra-bromdibenzo[-l,4]-dioxin) during subsequent incineration (Buser 1986). Mixed cultures of organisms isolated from sediments contaminated with PCBs and PBBs were shown to debrominate PBBs under anaerobic conditions (Morris et al. 1992), and the dominant congener — 2,4,5,2,4, 5 -hexabro-mobiphenyl — could be successively debrominated to 2,2,-dibromobiphenyl. On the other hand, in sediments from the most heavily contaminated site containing contaminants in addition to PBBs, very little debromination occurred and the recalcitrance was attributed to the toxicity of the other contaminants (Morris et al. 1993). 

Proposals to ban two types of brominated flame retardants in electrical and electronic goods are raising controversy in Bmssels. The EU DG XI (Environment) is circulating a draft proposed directive on waste electrical and electronic equipment under which polybrominated biphenyls and polybrominated diphenyl ethers would be banned by 1 January 2004. The proposal is circulating despite risk assessments which show that there is no particular cause for concern and no need for further risk assessment. 

ATSDR (2004) Toxicological Profile for Polybrominated Biphenyls and Polybrominated Diphenyl Ethers... 

TOXICOLOGICAL PROFILE FOR POLYBROMINATED BIPHENYLS AND POLYBROMINATED DIPHENYL ETHERS... 

Peer reviewers for the second draft (pre-public comments) of the toxicological profile on polybrominated biphenyls and polybrominated diphenyl ethers are as follows ... 

The purpose of this chapter is to describe the analytical methods that are available for detecting, measuring, and/or monitoring polybrominated biphenyls and polybrominated diphenyls ethers, their metabolites, and other biomarkers of exposure and effect to polybrominated biphenyls and polybrominated diphenyls ethers. The intent is not to provide an exhaustive list of analytical methods. Rather, the intention is to identify well-established methods that are used as the standard methods of analysis. Many of the analytical methods used for environmental samples are the methods approved by federal agencies and organizations such as EPA and the National Institute for Occupational Safety and Health (NIOSH). Other methods presented in this chapter are those that are approved by groups such as the Association of Official Analytical Chemists (AOAC) and the American Public Health Association (APHA). Additionally, analytical methods are included that modify previously used methods to obtain lower detection limits and/or to improve accuracy and precision. 

Agency for Toxic Substances and Disease Registry (2002) Toxicological Profile for Polybrominated Biphenyls and Polybrominated Diphenyl Ethers. Atlanta, GA US Department of Health and Human Services, Public Health Service. 

Lead is fotmd in paints, pigments, solder, etc. Mercury has been used in lighting applications and automotive switches, etc. Cadmium is in plastic pigmentation and photocells for nightlights, etc. Hexavalent chromium is used in metal finishing for corrosion prevention, while polybrominated biphenyls and polybrominated diphenyl ethers are flame retardants for several plastics. 

In addition, a draft of the proposed EC Directive on waste electrical and electronic equipment would ban some brominated compounds from 2004 (written in 1999). These are polybrominated biphenyls and polybrominated diphenyl ethers. The directive would also require all halogenated flame retardants to be removed fi om components in any waste equipment that is separately... 

Under the early draft, EU countries shall ensure that the use of lead, mercury, cadmium, hexavalent chromium, PBB, and PBDEs (polybrominated biphenyls and polybrominated diphenyl ethers) in electrical and electronic equipment is substituted on 1 January 2008. These have now become the subject of the Restriction of Hazardous Substances directive (RoHS). Additionally the Commission was proposing that all plastics containing BFRs be separated out from electrical and electronic equipment before recycling or disposal. 

EnvirOTimental trends are having an impact on electrical applications. Waste legislation includes WEEE (Waste of Electrical and Electronic Equipment) directive 2002/%/EC which holds producers responsible for collection and recovery of materials at end of Ufe. Additionally, materials that contain bromine-based flame retardants must be removed from the waste and handled separately. In restrictions on use of hazardous substances (ROHS) directive 2002/95/EC, the use of various hazardous materials is restricted. These include lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls, and polybrominated diphenyl ether. Since the introduction of Blue Angel in Germany in 1978, several other eco-labels have been implemented. These include TCO (Sweden), Nordic Swan, Milieukeur (Netherlands), and the EU Ecolabel. The general purpose of these labels is to provide cmisumers with information relating to the environmental impact of the products they purchase. 

ICP-OES, along with ICP-MS and X-ray fluorescence (XRE), is used for the analysis of the materials in electronic equipment. The EU has established directives on the disposal of waste electrical and electronic equipment (WEEE) and the restriction of the use of hazardous substances (RoHS) in electronic equipment sold in, into, and out of the EU. The maximum allowable quantities in electrical equipment of the following hazardous substances are 0.1% by weight for Pb, hexava-lent chromium (CrVI), mercury, and polybrominated biphenyl and polybrominated diphenyl ethers (PBDEs) and 0.01% by weight for Cd. Pb, Hg, Cd, and total Cr can be measured by ICP-OES, while the determination of hexavalent chromium requires a separation step in order to determine the oxidation state. This can be done using a hyphenated instrument, described in the following. Total bromine can also be measured by ICP-OES, but the determination of the PBDEs is generally done by GC-MS, described in Chapter 12. The WEEE/RoHS requirements have led many instrument manufacturers to have an installed method template for such analyses in their software. 

Luross, J.M., Alaee, M., and Sergeant, D.B. et al. (2002). Spatial distribution of polybromi-nated diphenyl ethers and polybrominated biphenyls in lake trout from the Laurentian Great Lakes. Chemosphere 46, 665-672. 

For this purpose, the WEEE Directive has been complemented with an additional directive that limits the use of certain pollutants in these products. The EC Directive 2002/95/EC on the Restriction of the use of certain Hazardous Substances in electrical and electronic equipment (RoHS Directive) ([7], recast 2011 [9]) restricts the use of the six harmful substances/substance families lead, mercury, hexavalent chromium, polybrominated biphenyls (PBB), and polybrominated diphenyl ethers (PBDE) to 0.1% and cadmium to 0.01% w/w per homogenous material in equipment and components, but with several exemptions for a wide range of applications (Annex III and IV). 

Table 1 Concentrations of chlorinated polycyclic aromatic hydrocarbons (CIPAHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in ambient air, soil, and human samples collected from e-waste recycling and reference sites in China... 

Bi XH, Thomas GO, Jones KC, Qu WY, Sheng GY, Martin FL, Fu JM (2007) Exposure of electronics dismantling workers to polybrominated diphenyl ethers, polychlorinated biphenyls, and organochlorine pesticides in South China. Environ Sci Technol 41(16) 5647-5653. doi 10.1021/es070346a... 

Wen S, Yang F, Li JG, Gong Y, Zhang XL, Hui Y, Wu YN, Zhao YF, Xu Y (2009) Polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs) monitored by tree bark in an e-waste recycling area. Chemosphere 74(7) 981-987. doi 10.1016/j.chemosphere.2008.10.002... 

Sjodin A, Jones RS, Focant JF, Lapeza C, Wang RY, McGahee EE, Zhang YL, Turner WE, Slazyk B, Needham LL, Patterson DG (2004) Retrospective time-trend study of polybrominated diphenyl ether and polybrominated and polychlorinated biphenyl levels in human serum from the United States. Environ Health Perspect 112(6) 654—658. doi 10.1289/ehp. 6826... 

Inoue K, Harada K, Takenaka K, Uehara S, Kono M, Shimizu T, TakasugaT, Senthilkumar K, Yamashita F, Koizumi A (2006) Levels and concentration ratios of polychlorinated biphenyls and polybrominated diphenyl ethers in serum and breast milk in Japanese mothers. Environ Health Perspect 114(8) 1179-1185. doi 10.1289/ehp.9032... 

BFRs are one of the last classes of halogenated compounds that are still being produced worldwide and used in high quantities in many applications. In order to meet fire safety regulations, flame retardants (FRs) are applied to combustible materials such as polymers, plastics, wood, paper, and textiles. Approximately 25% of all FRs contain bromine as the active ingredient. More than 80 different aliphatic, cyclo-aliphatic, aromatic, and polymeric compounds are used as BFRs. BFRs, such as polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA), have been used in different consumer products in large quantities, and consequently they were detected in the environment, biota, and even in human samples [26, 27]. 

Vorkamp K, Riget FR, Bossi R, Dietz R (2011) Temporal trends of hexabromocyclododecane, polybrominated diphenyl ethers and polychlorinated biphenyls in ringed seals from East Greenland. Environ Sci Technol 45 1243-1249... 

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