| Compound Name |
Hexabromocyclododecane |
| Stockholm Annex code | I, IV |
| Key |
Annex I to the regulation are subject to prohibition (with specific exemptions) on manufacturing, placing on the market and use; Annex II to the regulation are subject to restriction on manufacturing, placing on the market and use; Annex III to the regulation are subject to release reduction provisions; and Annex IV to the regulation are subject to waste management provisions. Note that for some substances listed in Annex I, specific exemptions on the prohibition of their use, manufacturing and placing on the market may apply. |
| Classification |
Intentional |
| Category |
A - (Elimination) Parties have put in place measures to eliminate the production and use of the chem |
| Year of Listing Decision |
2013 |
| Persistence |
Short biological half-life of 1–4 days |
| Specific exemptions associated with its use |
Production: As allowed by the parties listed in the Register of specific exemptions. |
| Acceptable purposes associated with its use |
Use: Expanded polystyrene and extruded polystyrene in buildings in accordance with the provisions of the Part VII Of Annex A Also used for latex binders, unsaturated polyesters, and polyvinyl chloride wire, cable, and textile coatings. Textile industry use include, its application as a back coating to the fabric, encapsulated in a polymer matrix. Textile industry use include residential and commercial furniture, up-holstery seating in transportation, draperies, and wall coverings. |
| Conventions on POPs |
Stockholm Convention Convention on Long-Range Transboundary Air Pollution Rotterdam Convention Basel Convention |
| Name |
Hexabromocyclododecane |
| Synonyms |
1,1,2,2,3,3-Hexabromocyclododecane 1235106-66-7 1,1,2,2,3,3-hexabromocyclododecane hexabromocyclododecane 1,1,2,2,3,3- Cyclododecan |
| Structure | Br)Br)Br)Br)Br.png)
Molecular Formula:
C12H18Br6
|
| CAS Number | 25637-99-4 |
| European Community (EC) Number | 247-148-4 |
| European Chemicals Agency (ECHA) | 247-148-4 |
| PubChem ID | 15724678 |
| DSSTOX Substance ID | DTXSID8025383 |
| KEGG | N/A |
| ChemSpider |
17499 |
| Similarity threshold | Name of Related Compound | DSSTox Substance ID | CAS Number | Molecular weight | Molecular formula |
|---|---|---|---|---|---|
| N/A | 1,2,5,6,9,10-hexabromocyclododecane | DTXSID4027527 | 3194-55-6 | 641.7 g/mol | C12H18Br6 |
| N/A | alpha-hexabromocyclododecane | DTXSID00873771 | 134237-50-6 | 641.7 g/mol | C12H18Br6 |
| N/A | beta-hexabromocyclododecane | DTXSID60873772 | 134237-51-7 | 641.7 g/mol | C12H18Br6 |
| N/A | gamma-hexabromocyclododecane | DTXSID20873773 | 134237-52-8 | 641.7 g/mol | C12H18Br6 |
| Description | Reference | Article Link |
|---|---|---|
| Hexabromocyclododecane (HBCD) is a globally produced brominated flame retardant (BFR) used primarily as an additive FR in polystyrene and textile products and has been the subject of intensified research, monitoring and regulatory interest over the past decade. HBCD is currently being evaluated under the Stockholm Convention on Persistent Organic Pollutants. HBCD is hydrophobic (i.e., has low water solubility) and thus partitions to organic phases in the aquatic environment (e.g., lipids, suspended solids). It is ubiquitous in the global environment with monitoring data generally exhibiting the expected relationship between proximity to known sources and levels; however, temporal trends are not consistent. Estimated degradation half-lives, together with data in abiotic compartments and long-range transport potential indicate HBCD may be sufficiently persistent and distributed to be of global concern. The detection of HBCD in biota in the Arctic and in source regions and available bioaccumulation data also support the case for regulatory scrutiny. Toxicity testing has detected reproductive, developmental and behavioral effects in animals where exposures are sufficient. Recent toxicological advances include a better mechanistic understanding of how HBCD can interfere with the hypothalamic-pituitary-thyroid axis, affect normal development, and impact the central nervous system; however, levels in biota in remote locations are below known effects thresholds. For many regulatory criteria, there are substantial uncertainties that reduce confidence in evaluations and thereby confound management decision-making based on currently available information. | Marvin et al., 2011. Hexabromocyclododecane: Current Understanding of Chemistry, Environmental Fate and Toxicology and Implications for Global Management. | Link |
| Hexabromocyclododecane is a solid, white powder that is used as a flame retardant additive for thermoplastic polymers. has been produced as a commercial mixture since the 1960s and is currently used as a flame retardant added to thermal insulation foams and textiles. The HBCD commercial mixture is made up of 16 possible stereoisomers with three predominating diastereomers: alpha, beta, and gamma. Releases of HBCD in the environment are detected globally and are increasing in certain regions. HBCD, with alpha-HBCD being the dominant isomer, has been found to be widespread in humans and wildlife. Evidence supports the classification of HBCD as persistent, bioaccumulative, and toxic, which also undergoes long-range environmental transportation. HBCD is a nuclear receptor agonist, an endocrine disruptor, and a hepatotoxicant, and it causes developmental neurotoxicity in laboratory animals and wildlife. Few human studies have investigated effects of HBCD, and no studies with HBCD stereoisomers could be found. Due to its persistence, bioaccumulation, long-range transport, and toxicity profile, HBCD has been nominated for inclusion as a persistent organic pollutant under the UN Environment Programme's Stockholm Convention on Persistent Organic Pollutants. | Szabo., 2014. Hexabromocyclododecane. | Link |
| Flame retardants are chemicals that are added to or reacted with combustible materials to increase their fire resistance. They are applied to combustibles materials like plastics, woods, paper, and textiles. Flame-retarded polymers are widely used in cars, consumer electronics, computers, electrical equipment, and building materials. They can find their way into the environment as wastewaters of industrial facilities that produce FRs and manufacturing facilities that incorporate such compounds into products, through volatilization and leaching from products during manufacturing or usage, upon breakdown of foam products, or by disposal of products (eg, electronic equipments), through leaching from landfills, combustion and recycling of waste products, or adsorption onto dust particles. They are classified into four major chemical groups: inorganic, organophosphorous, halogenated organic, and nitrogen-based compounds. Halogenated organic flame retardants are further classified as containing either chlorine or bromine. Approximately 25% of all FRs (volume basis) contain bromine. They can be divided into different subgroups depending on their mode of incorporation into the polymers. Additive brominated flame retardants (BFRs) are mixed together with the other components of the polymers; they comprise compounds such as polybrominated biphenyls (PBBs), polybrominated diphenylethers (PBDEs), and hexabromocyclododecane (HBCD). Reactive BFRs are a group of compounds such as tetrabromobisphenol A (TBBPA) that are chemically bonded to the plastics. Polymeric BFRs include compounds like brominated polystyrene (BPS), where bromine atoms are incorporated in the backbone of the polymer resulting in a more stable chemical structure with very high molecular weight, low volatility, bioavailability, and toxicity. PBBs, PBDEs, TBBPA, and HBCD are also characterized by low vapor pressures and low solubility in water. In general, volatility decreases with rising bromine content; therefore highly brominated compounds are estimated to be nonvolatile, while low-brominated compounds will be more mobile in water and have a greater tendency to evaporate from surface water. The values of log Kow range from 4.5 for low-brominated compounds (TBBPA) to 10 for decabromodiphenylether (deca-BDE) showing high bioaccumulation in aquatic biota for lowbrominated compounds. | Álvarez-Muñoz et al., 2016. Chapter 1 - Contaminants in the Marine Environment. | Link |
| Hexabromocyclododecane (HBCD) is a cycloaliphatic flameretardant additive with high bromine content. It is mainly used as an additive in expanded polystyrene (EPS) and extruded polystyrene (XPS) foam in buildings, vehicles and textiles for thermal insulation. Moreover, lower amounts of HBCD are also used in electrical and electronic equipment HBCD is produced by bromination of cyclododecatriene (COT). HBCD has 6 stereogenic centers and is composed of 16 possible stereoisomers (6 enantiomeric pairs and 4 meso forms). The three most common forms of HBCD found in technical blends, environmental and biotic samples are the alpha-, beta-, gamma-diastereomers (approximately 10%–13% alpha-HBCD, 1%–12% beta-HBCD, 75%–89% gamma-HBCD). The three main diastereomers have different values of polarity, dipole moment and water solubility, which may cause different stabilities and biological uptake rates in the environment. | Wang et al., 2019., Temporal–spatial distribution and diastereoisomer pattern of hexabromocyclododecane in the vicinity of a chemical plant. | Link |