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Marteinson SC, Bodnaryk A, Fry M, Riddell N, Letcher RJ, Marvin C, Tomy GT, Fernie KJ. A review of 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane in the environment and assessment of its persistence, bioaccumulation and toxicity. Environ Res 2021; 195:110497. [PMID: 33232751 DOI: 10.1016/j.envres.2020.110497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/12/2020] [Accepted: 11/14/2020] [Indexed: 06/11/2023]
Abstract
Following the ban of many historically-used flame retardants (FRs), numerous replacement chemicals have been produced and used in products, with some being identified as environmental contaminants. One of these replacement flame retardants is 1,2-dibromo-4-(1,2-dibromoethyl)-cyclohexane (DBE-DBCH; formerly abbreviated as TBECH), which to date has not been identified for risk assessment and potential regulation. DBE-DBCH technical mixtures consist largely of α- and β-diastereomers with trace amounts of γ- and δ-DBE-DBCH. The α- and β-isomers are known contaminants in various environmental media. While current global use and production volumes of DBE-DBCH are unknown, recent studies identified that DBE-DBCH concentrations were among the highest of the measured bromine-based FRs in indoor and urban air in Europe. Yet our mass balance fugacity model and modeling of the physical-chemical properties of DBE-DBCH estimated only 1% partitioning to air with a half-life of 2.2 d atmospherically. In contrast, our modeling characterized DBE-DBCH adsorbing strongly to suspended particulates in the water column (~12%), settling onto sediment (2.5%) with minimal volatilization, but with most partitioning and adsorbing strongly to soil (~85%) with negligible volatilization and slow biodegradation. Our modeling further predicted that organisms would be exposed to DBE-DBCH through partitioning from the dissolved aquatic phase, soil, and by diet, and given its estimated logKow (5.24) and a half-life of 1.7 d in fish, DBE-DBCH is expected to bioaccumulate into lipophilic tissues. Low concentrations of DBE-DBCH are commonly measured in biota and humans, possibly because evidence suggests rapid metabolism. Yet toxicological effects are evident at low exposure concentrations: DBE-DBCH is a proven endocrine disruptor of sex and thyroid hormone pathways, with in vivo toxic effects on reproductive, metabolic, and other endpoints. The objectives of this review are to identify the current state of knowledge concerning DBE-DBCH through an evaluation of its persistence, potential for bioaccumulation, and characterization of its toxicity, while identifying areas for future research.
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Affiliation(s)
- Sarah C Marteinson
- Environment and Climate Change Canada, 867 Lakeshore Rd, Burlington, ON, L7S 1A1, Canada
| | - Anjelica Bodnaryk
- University of Manitoba, Department of Biological Sciences, Winnipeg, MB, R3T 2N2, Canada
| | - Mark Fry
- University of Manitoba, Department of Biological Sciences, Winnipeg, MB, R3T 2N2, Canada
| | - Nicole Riddell
- Wellington Laboratories, 345 Southgate Dr., Guelph, ON, N1G 3M5, Canada
| | - Robert J Letcher
- Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, 1125 Colonel By Dr., Ottawa, ON, K1S 5B6, Canada
| | - Chris Marvin
- Environment and Climate Change Canada, 867 Lakeshore Rd, Burlington, ON, L7S 1A1, Canada
| | - Gregg T Tomy
- University of Manitoba, Department of Chemistry, Winnipeg, MB, R3T 2N2, Canada
| | - Kim J Fernie
- Environment and Climate Change Canada, 867 Lakeshore Rd, Burlington, ON, L7S 1A1, Canada.
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