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Environmental fate & pathways

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EBP did not bioconcentrate in fish exposed via water over an 8 week period (METI 1991). However, the study was performed with the aid of dispersants at concentrations greater than its water solubility, and because of this, the results will not be considered further. It should be noted, however, that concentrations above the detection limit were detected in fish only once during study at week 2 of exposure. Further, based on EBP's measured water solubility and the study's detection limit, the study was capable of determining a BCF of 1700.

In another study (Schneider et al., 2019) Bluegill were exposed to a commercial diet treated at a nominal concentrations of 100 µg/g EBP + 10 µg/g PCB for 28 Days and 1000 µg/g EBP + 100 µg/g PCB for 56 Days and a control group fed with untreated diet only. The calculation of the BMF parameters was based on the EBP equivalent concentrations determined by LSC in the diet and in fish tissues and mean measured concentrations of PCB in the diet and fish tissues. Results from the uptake and depuration phase indicate that EBP did not bioaccumulate in fish tissue. Analysis of gut track tissue show that the test material was retained in the gut and that no metabolism occurred. Complete depuration of very little test substance in the tissue occurred within the first day below the limit of quantification. Therefore a kinetic depuration constant could not be determined. Indicative lipid-corrected steady-state BMF values for the EBP in the low and high treatment groups were 0.0030 and 0.0010, respectively. 

A second study is underway to confirm the results in a setting without simultaneaour exposure to benchmark chemicals. This study essentially confirmed the results of Xiao et al., 2013 who established EBP as a bechmark chemical for a negligible absorption efficiency in fish gastro-intestinal tract.

Water exposures to EBP are expected to be limited by its low water solubility (~0.72 ug/L and probably lower) and high adsorption to particulates as reflected in the ratio of mean dissolved to particulate concentrations, 0.00000079, (data from He et al. 2012 in the Pearl River, China). Diffusion-limited uptake across the gills is expected due to EBP's high molecular weight (~972) and large molecular size and shape.

A lack of bioaccumulation and/or biomagnification is expected. Substances with a Log Kow <4 are not expected to bioaccumulate. EBP measured Log Kow is 3.55 which was corroborated by the ratio of the water and octanol solubility. Modelled log Kows on the contrary are extremely high (e.g. 13.6, Xiao et al 2013), but also such an extremely high log Kow is normally considered as leading to a low potential for bioaccumulation. Further, EBP's measured octanol solubility, 850 ug/L, is below the value (0.002 mmol/L) which is considered in the REACH Guidance as an indicator of low potential for bioaccumulation. Results from the field studies of He et al. 2012 and Law et al. 2006 indicate a lack of bioaccumulation and/or biomagnification in freshwater fish.

Terrestrial bioaccumulation is not expected based on the rat ADME studies, negligible water and organic solvent solubility of the substance, high binding to particulates, and in vitro studies showing negligible solubility in cell culture media. Results of field studies are not indicative of bioaccumnulation or biomagnification. EBP was not detected in bobwhite egg albumin or yolk (LOD= 1 mg/kg ww) after 20 wks administration of 1000 ppm a.i. in the diet to male and female adult birds.

Guerra et al. (2012) did not detect DBDPEthane in 13 peregrine falcon eggs collected in Spain from 2003 to 2006. McKinney et al. (2011)did not detect DBDPEthane in adipose of polar bears collected in East Greenland and Svalbard between 2005 – 2008. Tlustos et al. (2010)reported decabromodiphenylethane was not detected in milk, eggs, fat and liver samples sampled in Ireland by the Food Safety Authority of Ireland. Analyses were performed by the Food and Environment Research Agency, York, UK. A total of 100 composite samples were prepared after collection of individual sub-samples at the production or processing stage. These included 30 milk samples, 20 egg samples, 38 samples of carcass fat taken from beef cattle, pigs, lambs, chickens and ducks, and 12 samples of liver (bovine, porcine, ovine, equine and avian). Samples were supplied by officers of the Department of Agriculture, Fisheries and Food at production level (slaughterhouse – fat and liver, farm/dairy tanker – milk, packing station – eggs. Analysis was via GC-HRMS using 13C-labelled surrogates.   The authors noted that a recent survey in the UK had also not detected the substance. 

However, more recent studies have detected EBP in some species, but further analysis is needed and will be provided with the next update of the dossier including the main BCF study that is currently under way.