United nations sc

Synthesis of information

129. 
     C-decaBDE is still produced and used as a flame retardant in many countries. BDE-209, the main component of c-decaBDE, is ubiquitous in the global environment, including biota. Monitoring data provide evidence for environmental emission from a wide range of sources, as well as long-range environmental transport over great distances.
     
130. 
     High persistency of BDE-209 in soil and sediment is demonstrated in several studies. Reported half-lives in sediment and soil are high and range from >180 days to 50 years, depending on the environmental conditions.
     
131. 
     Although BDE-209 is persistent in soil, sediment and air, it is known to debrominate to lower brominated PBDEs in the environment and biota. Debromination is indicated as a major concern in a number of assessments as some of the lower brominated PBDEs that are formed are known to be more bioaccumulative, toxic and persistent and to have a greater tendency to undergo long-range environmental transport than the fully brominated BDE-209. Some of the PBDEs formed are also listed POPs. Studies have shown debromination in biota and in environmental matrices. Several PBDE congeners that are not part of c-decaBDE have been identified and are considered to provide evidence for debromination. C-decaBDE and BDE-209 are also a source to highly toxic PBDD/PBDF and hexabromobenzene. PBDD/PBDF are found as impurities in c-decaBDE and may be formed unintentionally during e.g. UV-exposure, industrial-, waste- and recycling operations.
     
132. 
     Both oceanic and atmospheric processes contribute to the long-range environmental transport of BDE-209, but atmospheric particle transport is believed to be the main mechanism. The estimated atmospheric half-life in air is 94 days, but the life-time can exceed 200 days. In the Arctic and other remote regions BDE-209 is found in various environmental compartments including air, sediment, snow, ice and biota.
     
133. 
     BDE-209 released to the environment is bioavailable and taken up by organisms, including humans. BDE-209 is widely distributed in the global environment and high body burdens have been demonstrated in some species. Common kestrels in China contained some of the highest BDE-209 levels ever reported in wildlife, while increasing levels have been observed in peregrine falcons from Greenland, North-America and Sweden. Temporal trends indicate that the levels of BDE-209 were increasing in the Arctic atmosphere from 2002-2005 with a doubling time in the range of 3.5-6.2 years. In the period 2009-2013 no temporal trends of BDE-209 in air have been observed.
     
134. 
     BDE-209 can transfer from mother to off-spring and exposure takes place during early development. Maternal transfer to eggs and offspring has been reported in fish, amphibians, birds and reindeer. In humans, exposure to BDE-209 takes place in the early phases of development in utero via placental transfer and postnatally via mother's milk. In addition infants and toddlers are reported to have higher body burdens of BDE-209 and other PBDEs than adults due to a higher exposure to dust. In humans elevated levels have been reported in electronic dismantler workers, computer technicians, injection workers at electrical application factories and people residing near production and recycling facilities.
     
135. 
     The equivocacy in the available bioaccumulation data largely reflects species differences in uptake, metabolism and elimination, differences in exposure regimes and analytical challenges in measuring BDE-209. The BCF for BDE-209 in fish has been estimated to be <5000 with non-appreciable aqueous uptake predicted due to its large molecular size and low water solubility (<0.1 μg/L at 24 °C). However, the most important exposure route for BDE-209 in aquatic and terrestrial food webs is through the diet, and when considering the bioaccumulative behaviour of BDE-209, calculated or measured BAFs, BMFs and TMFs are believed to give more relevant information than calculated or measured BCFs. Although some studies do not demonstrate BDE-209 bioaccumulation and trophic dilution has been observed (TMF<1), bioaccumulation has been reported for a number of aquatic and terrestrial organisms (BAFs>5000, BMFs>1 and TMF>1).
     
136. 
     There is evidence that BDE-209 can result in adverse effects to reproductive health and output in fish, earthworm, mouse and rats as well as developmental- and neurotoxic effects in amphibians, rodents and humans. For some organisms such as frogs, mammals, fish and birds adverse effects levels reported for BDE-209 are close to or within the range of reported environmental levels. Measured body burden levels in the mammals and Arctic fish are in the range or above the low dose effects found in laboratory, such as neurodevelopmental effects in fish and mammals and reproductive effects in fish at vulnerable life stages. Due to debromination, organisms are moreover co-exposed to a complex mixture of PBDEs, including the already listed POPs BDEs. On the basis of the established common adverse outcomes, there is a concern that BDE-209 and other PBDEs combined may cause developmental neurotoxicity in both humans and wildlife at environmentally relevant concentrations.
     
137. 
     There is an increasing concern about endocrine disruptive chemicals since they can cause adverse effects at low environmental levels and the timing of exposure can be more critical than the level of exposure (UNEP/WHO 2013). Available toxicity data shows that BDE-209, similarly to other PBDEs, may act as an endocrine disruptor, and interfere with TH homeostasis in fish, amphibians, rat, mice and humans, and possibly with steroid hormone homeostasis. This fact, combined with debromination and co-exposure to BDE-209 and other similarly acting PBDEs, some of which are listed POPs, as well as the high persistency of BDE-209 in sediments and soils, increases the likelihood for chronic long-term adverse effects.
     

Table 3. POP characteristics of BDE-209, the main component of c-decaBDE

Criterion	Meets the criterion (Yes/No)	Remark
Persistence	Yes	Dated sediment cores indicate no degradation over a period of almost 30 years (Kohler 2008). Reported half-life in sediment range between 6 and 50 years, with an average of around 14 years at 22°C and under dark conditions (Tokarz 2008). Degradation half-life in sludge-amended soil under aerobic and anaerobic conditions >360 days (Nyholm 2010, 2011, as cited in ECHA 2012 a). No degradation of decaBDE after 180 days in soil samples spiked with BDE-209 (Liu 2011a) Temporally increasing concentrations is observed in some organisms and support the picture of BDE-209 as a persistent substance (e.g. Vorkamp 2005). Debrominates to lower brominated PBDEs with PBT/vPvB and POP properties that are known to be persistent (ECHA 2012a, POPRC 2013a)
Bio-accumulation	Yes	Found in elevated concentrations in top predators (Shaw 2008, 2009, 2012, Voorspoels 2006a, Jenssen 2007, Sørmo 2006, Verreault 2005, Pountney 2014). Log Kow ranging between 6.27 to 12.11 (CMABFRIP 1997, Dinn 2012, ECA 2010, Kelly 2007, Tian 2012, US EPA 2010, Watanabe and Tatsukawa 1990). (). BAF>5000 and BMFs>1 in aquatic organisms (Baron 2013, Law 2006, Jenssen 2007, Mo 2012, Shaw 2009, Tomy 2009, Frouin 2013) BMFs >1 in terrestrial organisms (Yu 2011, 2013, She 2013, Wu 2009a). TMFs> 1 in Arctic aquatic organisms (Law 2006). Debrominates to lower brominated PBDEs with PBT/vPvB and POP properties that are known to bioaccumulate (ECHA 2012a, POPRC 2013A) Toxic effects are observed at low and/ or environmentally relevant concentrations in birds, fish and frog (ECHA 2012a, Plourde 2013, Kuo 2010, Qin 2010, Wu 2009a, Liu 2011c)
Potential for Long-Range Environmental Transport	Yes	Widespread in the Arctic environment and biota (de Wit 2006, 2010, ECA 2010, NCP 2013). Monitoring data on BDE-209 levels in moss from Norway show that levels decrease from southern to northern Norway (Mariussen 2008) When bound to fine air particles BDE-209 can remain airborne for hours or days, provided it is not removed by wet deposition (Wilford 2008, Meyer 2012). The estimated atmospheric half-life in air is 94 days in air, but the life-time can be > 200 days (Breivik 2006, Raff and Hites 2007). DecaBDE debrominates to lower brominated PBDEs with PBT/vPvB and POP properties that are known to undergo long-range environmental transport (ECHA 2012a, POPRC 2013a)
Adverse effects	Yes	BDE-209 exerts reproductive, developmental, endocrine and neurotoxic effects in aquatic organisms, mammals and birds. Effects on growth, survival and mortality are also reported. Key data include: Delayed metamorphosis in tadpoles with a tentative NOEC below 1 μg/L (Qin 2010 in ECHA 2012a). TH disruptive effects and mortality in fathead minnow chronic 28 d-LOEL of ~3 ng/g BDE-209 bw/day or 0.41 ng/g ww food (Noyes 2013). Mortality of up to 98% in chicken embryos after 20 days following a single egg injection with BDE-209 (LD50 of 44 μg/ egg or 740 μg/ kg ww, Sifleet 2009 in ECHA 2012a). Developmental neurotoxicity in rodents (e.g. Johansson 2008, Viberg 2003, 2007, Rice 2009, Fujimoto 2011, Heredia 2012, Reverte 2013, 2014, Buratovic 2014). Epidemiological association for cognitive developmental effects in humans with decaBDE exposure (Gascon 2012, Chao 2011). Several studies suggest that adverse effects may occur at BDE-209 concentations at or close to environmentally relevant levels in fish, frogs, birds and mammals (Kuo 2010, Wu 2009a, Liu 2011c, Qin 2010, Noyes 2013, Sifleet 2009, ECHA 2012a, Pountney 2014, Tomy 2008, 2009). Debromination to lower brominated PBDEs with PBT/vPvB and POP properties that are known to have significant adverse effects (ECHA 2012a, POPRC 2013a, POPRC6 and POPRC7). Potential risk to humans and wildlife resulting from combined effects between BDE-209 and other PBDEs at environmentally relevant concentrations (e.g. Kortenkamp 2014, Plourde 2013). Potential risk for low-dose effects during sensitive developmental periods as a result of endocrine disruption (UNEP/WHO 2012, Johansson 2008, Viberg 2003, 2007, Rice 2009, Fujimoto 2011, Heredia 2012, Reverte 2013, 2014, Buratovic 2014, Noyes 2013).

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