Elucidating the Variability in the Hexabromocyclododecane Diastereomer Profile in the Global Environment

• Published in: Environmental science & technology Vol. 52; no. 18; pp. 10532 - 10542
• Main Authors: Li, Li, Wania, Frank
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 18.09.2018
• Subjects: air; Air pollution; Arctic region; Bioaccumulation; Computer simulation; Contamination; diastereomers; Emissions; environmental fate; Environmental impact; Flame retardants; hexabromocyclododecane; International regulations; Isomerization; material flow analysis; Multimedia; Polar environments; Relative abundance; Spatial variations; Variability; Arctic region
• ISSN: 0013-936X; 1520-5851; 1520-5851
• DOI: 10.1021/acs.est.8b03443

Hexabromocyclododecane (HBCDD) is a hazardous flame retardant subject to international regulation. Whereas γ-HBCDD is a dominant component in the technical HBCDD mixture, the diastereomer profile in environmental samples shows substantial temporal and spatial variations, ranging from γ- to α-HBCDD-dominant. To explain such variability, we simulate the global emissions and fate of HBCDD diastereomers, using a dynamic substance flow analysis model (CiP-CAFE) coupled to a multimedia environmental fate model (BETR-Global). Our modeling results indicate that, as of 2015, 340–1000 tonnes of HBCDD have been emitted globally, with slightly more γ-HBCDD (50%–65%) than α-HBCDD (30%–50%). Emissions of γ-HBCDD primarily originate from production and other industrial processes, whereas those of α-HBCDD are mainly associated with the use and end-of-life disposal of HBCDD-containing products. Presently, α-HBCDD dominates the contamination in the air of populated areas, while γ-HBCDD is more abundant in remote background areas and in regions with HCBDD production and processing facilities. Globally, the relative abundance of α-HBCDD is anticipated to increase after production of HBCDD is banned. Due to isomerization, α-HBCDD accumulates to a larger extent than γ-HBCDD in Arctic surface media. Since α-HBCDD is more persistent and bioaccumulative than other diastereomers, isomerization has bearing on the potential environmental and health impacts on a global scale.