Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The registered (parent) substance 1,3-bis(trimethylsilyl)urea hydrolyses rapidly under environmentally relevant conditions (DT50 < 10 min at pH 4, 7 and 9, 20 °C, OECD 111) and forms the silanol hydrolysis product trimethylsilanol (CAS No. 1066-40-6) and urea (CAS No. 57-13-6), which are considered the relevant assessment entities for the environmental hazard and risk assessment according to Guidance R.16 (ECHA, 2016).

Trimethylsilanol

The silanol hydrolysis product trimethylsilanol (TMS) is considered to be a stable degradant of the registered (parent) substance. It is characterized by a high, estimated water solubility of 1000 g/L (QSAR) and an estimated vapour pressure of 1850 Pa (QSAR). It is not readily biodegradable but has a low, estimated log Kow of 1.14 (QSAR), and a low estimated log Koc in the range of 0.99 to 1.64 (QSAR), indicating a low potential for bioaccumulation and adsorption to soil and sediment. Based on its properties, trimethylsilanol is expected to predominantly partition to the water column. The SimpleTreat model v4.0 predicts 99.07% of the substance to partition to water and the remaining fraction to air (0.33%), the primary settler (0.39%) and surplus sludge (0.21%).

Urea

Urea is well described in the public domain. It is expected to primarily distribute into the water (99.84%) and air (0.16%) compartments, based on modeling results (Mackay level 1). However, according to worldwide use patterns, the highest environmental exposure is to soil because of its wide use as fertilizer. Environmental exposure by consumer use is considered insignificant (OECD SIDS, 2002).

Reference

OECD SIDS (2002); Urea, CAS 57-13-6, SIAM 2 Final Assessment Report, UNEP Publications