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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Classification & Labelling & PBT assessment

PBT assessment

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Administrative data

PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB

Persistence assessment:

Hydrolysis: The substance is hydrolytically unstable in water with a half-life < 4 min at pH 4, 7 and 9 and at 20 ºC (read-across test method OECD 111, GLP study) and therefore the substance is not persistent. Nevertheless, the hydrolysis product MPKO is hydrolytically stable with a half-life > 1 year at pH 4, 7 and 9. In addition, a ready biodegradation test (CO2 evolution) indicates that both OS9600 and MPKO are not readily biodegradable (read-across, test method OECD 301B, GLP study).

Conclusion on P / vP properties: No conclusion can be reached based on available information.

Bioaccumulation assessment:

The substance hydrolyses very rapidly (half-life < 4 min) into MPKO and the corresponding vinyltrisilanol. Moreover, the trisilanol undergo continuous condensation reactions to produce higher molecular weight siloxanes which are considered biologically unavailable. The relevant hydrolysis product that will eventually end up in the environment is MPKO. Based on a log Kow value for MPKO of 1.25 (test method OECD 107, GLP study). In addition, the estimated BCF for MPKO is 12.83 (EPI-Suite, BCFBAF v3.01). Therefore it can be concluded that the substance is not bioaccumulative.

Conclusion on B / vB properties: The substance is not fulfilling the criteria for Biaccumulable (B)

Toxicity assessment:

There is no long-term toxicity study available with fish and crustacea.

Toxicity to aquatic algae: NOEC (72h) = 43 mg/L (basis for effect: growth rate) (read-across, test method OECD 201, GLP study).

Moreover, regarding the acute aquatic toxicity:

- Short-term toxicity to fish: LC50 (96h) > 134 mg/L (based on mortality) (read-across, test method OECD 203, GLP study).

- Short-term toxicity to aquatic invertebrates: EC50 (48h) > 134 mg/L (based on mobility) (read-across, test method OECD 202, GLP study).

- Toxicity to aquatic algae: EC50 (72h) = 118 mg/L (based on growth rate) (read-across, test method OECD 201, GLP study).

The substance is not classified as CMR.

The substance is not classified as STOT Rep. Exp. 2.

Conclusion on T properties: The substance is not fulfilling the criteria for Toxic (T).


OS9600 is not a PBT or vPvB substance.