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PBT assessment

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PBT assessment: overall result

Reference
Name:
Butan-2-one O,O',O''-(vinylsilylidyne)trioxime
Type of composition:
legal entity composition of the substance
State / form:
liquid
Reference substance:
Composition 1
PBT status:
the substance is not PBT / vPvB
Justification:

Persistence assessment:

Biodegradation in water: screening test: The substance is not ready biodegradable.

Hydrolysis: The substance is hydrolytically unstable in water. The half-life is expected to be < 1 hour at 25 ºC. Therefore, the substance is not persistent.

Conclusion on P / vP properties: The substance is not fulfilling the criteria for Persistence (P).

Bioaccumulation assessment:

The substance undergoes rapid hydrolysis in aqueous to butanone oxime and the corresponding vinylsilanetriol. According to the bioaccumulation test in carp fish performed by MITI, butanone oxime has a low bioaccumulation potential (BFC= (0.5)-(0.6) at a concentration of 2 ppm, and <2.5 -(5.8) at a concentration of 0.2 ppm). At the same time, silanetriols undergo continuous condensation reactions to produce higher molecular weight siloxanes which are considered biologically unavailable.

It should be also taken into accoun that the estimated log octanol-water partition coefficients (Log Kow) for the degradation products 2 -butanone oxime and vinylsilanetriol were 1.69 and -2.01 (EPI-Suite, KOWWIN v1.68). Since being the log Pow <3, they are expected to be of low bioaccumulation potential.

Based on the available information, the test item is determined to have low bioconcentration potential based on the properties of its degradation products.

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

Toxicity assessment:

- Long-term toxicity to fish: LC50 (14d) > 119.94 mg/L (based on mortality) and NOEC (14d) = 59.97.

- Long-term toxicity to aquatic invertebrates: LC50 (21d) > 119.94 mg/L (based on parental mortality), EC50 (21d) > 119.94 mg/L (based on reproduction) and NOEC (21d) >= 119.94 mg/L (based on reproduction).

- Toxicity to aquatic algae: NOEC (72h) = 3.12 mg/L (basis for effect: growth rate).

Moreover, regarding the acute aquatic toxicity:

- Short-term toxicity to fish: LC50 (96h) = 1011.11 mg/L (based on mortality).

- Short-term toxicity to aquatic invertebrates: EC50 (48h) = 241.08 mg/L (based on mobility).

- Toxicity to aquatic algae: EC50 (72h) = 19.19 mg/L (based on growth rate).

The substance is not classified as CMR.

The substance is classified as STOT Rep. Exp. 2 (target organ: red blood cells) in accordance with CLP Regulation (EC) No 1272/2008, since significant toxic effects were observed in a 90-day repeated-dose study (oral) conducted in experimental animals within value ranges 10 -100 mg/kg bw/day.

Conclusion on T properties: The substance is determined to be T.

CONCLUSION:

2-Butanone, O,O',O'' -(vinylsilylidyne)trioxime is not a PBT or vPvB substance.