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.

Table: Distribution modelling for STP

Fraction of emission directed to air by STP

87.3

[%]

Fraction of emission directed to water by STP

4.67

[%]

Fraction of emission directed to sludge by STP

8.01

[%]

Fraction of the emission degraded in STP

0

[%]

Hexamethyldisiloxane is not expected to undergo any significant biodegradation, has very high Henry’s Law constant and high log Kow/log Koc. Therefore air is the main compartment to which it is expected to partition in a sewage treatment plant. Some partition to sewage sludge and water is expected, and therefore potentially to soil/sediment compartments in the environment.