Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The distribution in a sewage treatment plant (STP) has been estimated using the SimpleTreat model (implemented in EUSES 2.1.2), see table below. Due to the moderate rate of hydrolysis of the parent substance, the distribution calculation is done for the registration substance itself.


Table. Distribution modelling for STP

Fraction of emission directed to air by STP



Fraction of emission directed to water by STP



Fraction of emission directed to sludge by STP



Fraction of the emission degraded in STP




4,4,13,13-Tetraethoxy-3,14-dioxa-8,9-dithia-4,13-disilahexadecane (S2) hydrolyses at a moderate rate in contact with water to (3-{[3-(trihydroxysilyl)propyl]disulfanyl}propyl)silanetriol. S2 is not expected to undergo any significant biodegradation, is predicted to have very high Henry’s Law constantand high log Kow/log Koc. Therefore air is the main compartment to which it is expected to partition in a sewage treatment plant.


The low solubility of S2 in water may affect distribution modelling in STP in the environmental exposure assessment. Please refer to Chapter 9 of the CSR.