Photochemical Formation of Polybrominated Dibenzo-p-dioxins from Environmentally Abundant Hydroxylated Polybrominated Diphenyl Ethers

• Published in: Environmental science & technology 2012-07, Vol.46 (14), p.7567-7574
• Main Authors: Arnoldsson, Kristina, Andersson, Patrik L, Haglund, Peter
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Applied sciences; Biological and medical sciences; Carbon - chemistry; Chemical reactions; Dioxins; Dioxins - chemistry; Earth sciences; Earth, ocean, space; Ecosystem; Ecotoxicology, biological effects of pollution; Engineering and environment geology. Geothermics; Environmental Pollutants - chemistry; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry; Halogenated Diphenyl Ethers - chemistry; Hydrocarbons, Halogenated - chemistry; Hydroxylation; Marine and brackish environment; Natural water pollution; PCB; Photochemical Processes - radiation effects; Pollutants; Pollution; Pollution, environment geology; Polybrominated diphenyl ethers; Polychlorinated biphenyls; Reproducibility of Results; Seawater - chemistry; Seawaters, estuaries; Time Factors; Toxicity; Ultraviolet radiation; Ultraviolet Rays; Water Pollutants, Chemical - analysis; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851; 1520-5851
• DOI: 10.1021/es301256x

High levels of polybrominated dibenzo-p-dioxins (PBDDs) have been found in Baltic Sea biota, where the toxic load owing to, for example, polychlorinated dibenzo-p-dioxins and other organic pollutants is already high. The levels and geographic pattern of PBDDs suggest biogenic rather than anthropogenic origin, and both biotic and abiotic formation pathways have been proposed. Photochemical formation from hydroxylated polybrominated diphenyl ethers (OH-PBDE) is a proposed pathway for PBDDs in marine environments. Ultraviolet radiation-initiated transformations of OH-BDEs 47, 68, 85, 90, 99, and 123, which all are abundant in the environment, were investigated. It was shown that the most abundant PBDDs in the environment (1,3,7-triBDD and 1,3,8-triBDD) can be formed from the most abundant OH-BDEs (OH-BDE 47 and OH-BDE 68) at high rates and with percentage yields. In fact, most of the PBDDs that have been identified in the Baltic Sea environment were formed with high yield from the six studied OH-PBDE, through initial cyclization and subsequent debromination reactions. The high formation yields point to this route as an important source of PBDDs in biota. However, congeners showing relatively high retention in fish, specifically 1,3,6,8- and 1,3,7,9-tetraBDD, were not formed. These are likely formed by enzymatic coupling of brominated phenols.