Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Distribution modelling

TBBPA's transport and distribution between environmental compartments was modelled using EPISuite v3.20, based on the chemical's structure. EPI v3.20 was used because later versions of this software included incorrect values in its reference library for certain brominated flame retardants.

Over 99% of TBBPA released to the environment is predicted to partition to soil (53%) and sediment (46%). Negligible amounts are predicted to partition to water (0.6%) and air (0.00008%) (Level III Fugacity Model; Emissions of 1000 kg/hr to each of air, water and soil). In soil and sediment, TBBPA is expected to bind extensively to organic carbon (estimated Koc soil = 6.5 x 10^6). Movement into groundwater is not expected based on this Koc and measured water solubility. TBBPA is expected to partition from water to organic carbon (Koc = 5.6 x 10^5). TBBPA is not expected to volatilize from water (Volatilization half-life in rivers = 6.7 x 10^5, in lakes = 7.3 x 10^6). In air, TBBPA is expected to be bound to particulates; the fraction sorbed to particulates is estimated to be 1 at 25 °C (AEROWIN v1.00). Its movement in the atmosphere will be governed by the particles to which it is bound. Sewage treatment plants are predicted to remove TBBPA from the influent to a high degree (94%), but biodegradation in the treatment plant is not expected. Removal in the treatment plant will be by partitioning to sludge. Leaching from polymers in which TBBPA is used is not expected, in part because its primary use is as a reactive flame retardant in printed circuit boards. However, due to its physical/chemical properties it is not expected to leach from polymers where it is used as an additive.

Other distribution data

In a chamber test performed with a personal computer housing containing TBBPA (Kemmlein et al. 2003), the emissions of TBBPA was measured. Due to its phenolic character, TBBPA has relatively low vapour pressure and tends to adsorb to surfaces. Over a 150-d test, no emission could be detected from the PC housing but measurement of TBBPA in the solvent used to rinse the test chamber walls showed 356 ng/m² of TBBPA on the chamber surfaces. Using this value, the area specific emission rate (SERa) was calculated to be 0.4 ng/m²/ h. The conclusion from the data is that losses from the computer housing were low.