1,1'-(ethane-1,2-diyl)bis[pentabromobenzene]

Endpoint summary

Description of key information

Stability and degradation

EBP was demonstrated to be stable and not biodegrade in several test systems, STP simulation systems, aerobic and anaerobic sediment and soil studies according to standard OECD test guidelines (OECD 308 and 307), but with prolonged exposure durations of 6 months. In the sediment it was verified that microorganisms capable of degrading organo-halogen compounds were present. A recent study in aerobic soils with 6 plant species also showed no formation of metabolites during the 61d exposure period. A study carried out to mimmick recycling in HIPS manufacture containing EBP and EBP and Sb2O3 under realistic worst case conditions and temperatures also revealed that the substance remained stable and only a minor increase of the Br9 -isomers occurred after 6 recycling cycles. Several studies in polymers and under incineration conditions have demonstrated that no polybrominated dioxin or-furans are formed during those processes.

Thus it can be concluded that the substance itself is very persistent and does not form degradation products that could have a higher bioaccumulation or toxicity potential under environmental conditions or under reasonable worst case use conditions.

Bioaccumulation:

Two recent guideline studies according to OECD 305 and GLP with dietary exposure were performed following the substance evaluation decision. These studies demonstrated the extremely low potential for bioaccumulation of EBP compared to known reference substances. It could also beconfirmed in those studies that the substance is hardly absorbed from the gastro-intestinal tract and the low tissue levels are depurated quickly. EBP was also used as a benchmark chemical that is poorly absorbed in fish by Xiao et al. 2013. With reagrd to a possible bioaccumulation potential in terrestrial organisms, several studies have shown that a trophic magnification is unlikely and the rat toxicokinetic study also suggests very little absorption and uptake in mammalian tissues after a single oral exposure.

Transport and distribution

Modeling indicates EBP is expected to partition in the environment to sediment and soil (ca. 99%). Negligible distribution to air and water are expected. High binding to particulates in all media is expected. Photolysis and hydrolysis are not expected to be significant routes of environmental degradation. Sewage treatment plants are expected to remove > 95% of that present in the influent. Removal is expected to be via binding to particulates rather than biodegradation. Volatilization is not expected due to the low vapour pressure. Monitoring data generally confirm this distribution pattern.

EBP's physical and chemical properties will limit exposure and uptake. EBP'scharacteristic travel distance is expected to be low and long range atmospheric transport is not expected. Its movement in the atmosphere will be governed by the particulates to which it is bound. Atmospheric losses are expected to occur via wet and dry deposition.