Biphenyls polybrominated

The principal source of pollution by polybrominated biphenyls (PBBs) has been the commercial mixture Firemaster, which was produced in the United States between 1970 and 1974. Production was discontinued in 1974 following a severe pollution incident in Michigan, when Firemaster was accidentally mixed with cattle feed on a farm. In due course, PBBs entered the human food chain via contaminated animal products. Substantial residues were found in humans from the area, and were snbse-quently found to be highly persistent. 

Firemaster is a stable solid, resembling a PCB mixture in its lipophilicity, chemical and thermal stability, and low vapor pressure. Firemaster contains some 80 ont of a possible 209 PBB congeners, but just two of them— 2,2, 4,4, 5,5-hexabromobiphenyl and 2,2, 3,4,4, 5,5, heptabromobiphenyl—account for around 85% of the commercial product (Environmental Health Criteria 152). These two componnds were fonnd to be very slowly eliminated by humans exposed to them during the Michigan incident. A half-life of abont 69 weeks was estimated for 2,4,5,2,4, 5 -HBB. 

Organic Pollutants An Ecotoxicological Perspective, Second Edition 

PCB mixtures were once used for a variety of purposes, and came to cause widespread environmental pollution. Over 100 different congeners are present in commercial products such as Aroclor 1248 and Aroclor 1254. PCBs are lipophilic, stable, and of low vapor pressure. Many of the more highly chlorinated PCBs are refractory, showing very strong biomagnification with movement along food chains. 

The toxicology of PCBs is complex and not fully understood. Coplanar PCBs interact with the Ah-receptor, with consequent induction of cytochrome P4501A1/2 and Ah-receptor-mediated toxicity. Induction of P4501A1 provides the basis of valuable biomarker assays, including bioassays such as CALUX. Certain PCBs, for example, 3,3, 4,4 -TCB, are converted to monohydroxymetabolites, which act as thyroxine antagonists. PCBs can also cause immunotoxicity (e.g., in seals). 

Anderson HA, Wolff MS, Lilis R, et al Symptoms and clinical abnormalities following ingestion of polybrominated-biphenyl-contaminated food products. Ann N Y Acad Sci 320 684-701, 1979 

Brown GG, Nixon RK Exposure to polybrominated biphenyls some effects on personality and cognitive functioning. JAMA 242 523-527,1979 Brown GG, Preisman RC, Anderson MD, et al Memory performance of chemical workers exposed to polybrominated biphenyls. Science 212 1413-1415,1981 Lilis R, Anderson HA, Valciukas JA, et al Comparison of findings among residents on Michigan dairy farms and consumers of produce purchased from these farms. Environ Health Perspect 23 105-109, 1978 

Meester WD, McCoy DJ Human toxicology of polybrominated biphenyls, in Management of the Poisoned Patient. Edited by Rumack BH, Temple AR. Princeton, NJ, Science Press, 1977, pp 32-60 

Schwartz EM, Rae WA Effect of polybrominated biphenyls (PBB) on developmental abilities in young children. Am J Public Health 73 277-281,1983 Seagull E Developmental abilities of children exposed to polybrominated biphenyls (PBB). Am J Public Health 73 281-285, 1983 Stross JK, Nixon RK, Anderson MD Neuropsychiatric findings in patients exposed to polybrominated biphenyls. Ann N Y Acad Sci 320 368-372,1979 Valciukas JA, Lilis R, Wolff MS, et al Comparative neurobehavioral study of a polybrominated biphenyl-exposed population in Michigan and a nonexposed group in Wisconsin. Environ Health Perspect 23 199-210,1978 Valciukas JA, Lilis R, Anderson HA, et al The neurotoxicity of polybrominated biphenyls results of a medical field survey. Ann N Y Acad Sci 320 337-367, 1979 Weil WB, Spencer M, Benjamin D, et al The effect of polybrominated biphenyls on infants and young children. J Pediatr 98 47-51,1981 

Aoki Y Polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans as endocrine disrupters—what we have learned from Yusho disease. Environ Res 86 2-11, 2001 

PBBs are normally prepared by direct bromination of biphenyl, using an aluminium chloride catalyst other manufacturing routes, using Friedal Craft processes, are possible [97]. The principal grade produced was basically a hexabromo- (Fire- 

Little information on properties is available it is shown in Table 3. Some contamination by brominated naphthalenes has been reported. 

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Except for polybrominated biphenyls (PBB), a limited number of studies regarding the toxicity of aromatic brominated compounds has been performed. Some experiments suggest a moderate acute toxicity of these compounds (ref. 1). 

Among aromatic bromine derivates, only polybrominated biphenyl is known to have a porphyrogenic effect (ref. 24). From scarce data about the toxicity of 4 and 5 porphyrogenic activity in the case of repeated administration could be expected (refs. 25,26). No data are available concerning the remaining compounds. 

The polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs) are indnstrial chemicals that do not occur naturally in the environment. The properties, uses, and toxicology of the PCBs are described in detail in Safe (1984), Robertson and Hansen (2001), and Environmental Health Criteria 140. PBBs are described in Safe (1984) and Environmental Health Criteria 152. 

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. 

Pijnenburg, A., Everts, J., and de Boer, J. et al. (1995). Polybrominated biphenyl and diphe-nylether flame retardants analysis, toxicity, and environmental occurrence. Reviews in Environmental Contamination and Toxicology. 141, 1-26. 

Safe, S. (1984). Polychlorinated biphenyls and polybrominated biphenyls biochemistry, toxicology and mode of action CRC Critical Reviews in Toxicology 13, 319-395. 

The dehalogenation of polychlorinated or polybrominated biphenyls was more rapid in cultures using inocula prepared from sediments contaminated with the chlorinated or bro-minated biphenyl, respectively (Morris et al. 1992). 

Mixed cultures of organisms that were isolated from sediments contaminated with PCBs and polybrominated biphenyls (PBBs) were shown to debrominate PBBs under anaerobic conditions (Morris et al. 1992), and the dominant congener—2,2, 4,4, 5,5 (245-245)-hexabromobiphenyl—could be successively debrominated to 2,2 -dibromobiphenyl. However, 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). 

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. 

The challenge was to avoid the use of hazardous brominated fire retardants such as polybrominated biphenyl (PBB) and pentabromodiphenyl ether (PBDE). The first strategy was to replace PBB and PBDE with tetrabromo-bisphenol-A (TBBA). This has a much lower toxicity, but is still a brominated fire retardant with safety concerns. An improvement... 

An important application of carbon-skeleton gas chromatography is the simplification of the analysis of complex samples such as polychlorinated biphenyls, polybrominated biphenyls and polychloroalkanes [709-711], These complex mixtures of halogenated isomers produce multiple peaks when separated by gas chromatography, making quantitation difficult. The isomers have identical carbon skeletons, resulting in a very simple chromatogram after hydrodechlorination. 

Griffin, R.A. Chou, S.F.J. "Attenuation of Polybrominated Biphenyls and Hexachlorobenzene by Earth Materials," Environ. Geol. Note 87. Illinois Institute of Natural Resources, Urbana, IL, 1980. 

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... 

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]. 

Stratton CL, Mousa JJ, Bursey JT (1979) Analysis for polybrominated biphenyls (PBBs) in environmental samples, US EPA, report no 560/13-79-001... 

Griffin, R.A., Chou, S.J. (1981) Attenuation of polybrominated biphenyls and hexachlorobenzene in Earth Materials. Final Report, U.S. EPA-600/2-81-191. Urbana, II Illinois State Geological Survey, pp. 60. 

Safe, S. 1984. Polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs) biochemistry, toxicology, and mechanism of action. Crit. Rev. Toxicol. 13 319-393. 

Abbreviations PAH = polyaromatic hydrocarbon, TCDD = Tetrachlorodibenzo-p-dioxin, PCB = polychlorinated biphenyl, PBB = polybrominated biphenyl, TBTO = tributyltin oxide, DBTO = dibutyltin oxide, TPT = triphenyltin. 

Organobrominated substances Polybrominated biphenyl ethers Bromophenols Dioxin-like compounds Tetrabromobisphenol A... 

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