Butan-2-one O,O',O'',O'''-silanetetrayltetraoxime

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Remarks:

Internationally accepted method, EPI-Suite, EPA (USA)

Justification for type of information:

See attached the QMRF and QPRF for the QSAR model.

Principles of method if other than guideline:

Calculation by EPI-Suite, EPA (USA) / BIOWIN v4.10

GLP compliance:

no

Parameter:

probability of ready biodegradability (QSAR/QSPR)

Remarks on result:

other: not readily biodegradable based on QSAR/QSPR prediction

The substances butan-2-one O,O',O'',O'''-silanetetrayltetraoxime is predicted not to be readily biodegradable by EPI-Suite, EPA (USA) / BIOWIN v4.10.

Validity criteria fulfilled:

not applicable

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The substances butan-2-one O,O',O'',O'''-silanetetrayltetraoxime is predicted not to be readily biodegradable by EPI-Suite, EPA (USA) / BIOWIN v4.10 calculation method.

Executive summary:

The substances butan-2-one O,O',O'',O'''-silanetetrayltetraoxime is predicted not to be readily biodegradable by EPI-Suite, EPA (USA) / BIOWIN v4.10 calculation method.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
The analogue butan-2-one O,O',O''-(methylsilanetriyl)oxime which shares the same functional group with butan-2-one O,O',O'',O'''-silanetetrayltetraoxime, also has comparable values for the relevant molecular properties for biodegradation.
See attached reporting format.

Reason / purpose for cross-reference:

read-across source

GLP compliance:

no

Parameter:

other: BOD (NO2)

Value:

20

Sampling time:

28 d

Remarks on result:

other: (Results based on analogue substance butan-2-one O,O',O''-(methylsilanetriyl)oxime)

Parameter:

other: (NH3)

Value:

26

Sampling time:

28 d

Remarks on result:

other: (Results based on analogue substance butan-2-one O,O',O''-(methylsilanetriyl)oxime)

Parameter:

% degradation (TOC removal)

Value:

28

Sampling time:

28 d

Remarks on result:

other: (Results based on analogue substance butan-2-one O,O',O''-(methylsilanetriyl)oxime)

Details on results:

The analogue substance butan-2-one O,O',O''-(methylsilanetriyl)oxime was hydrolyzed to form 2-Butanone oxime(2-0546, persistence, Low-Bioconcentration), Monomethylsilanol, and polymer (Polysiloxane) of the Monomethylsilanol. Analysis of the test substance was difficult. Based on these results the test item butan-2-one O,O',O'',O'''-silanetetrayltetraoxime is also expected to hydrolyse to forom 2-butanoe oxime and the corresponding silanol and polysiloxane.

As indicated in the European Chemical Agency Practical Guide 6 “How to report read –across and categories”, the structural grouping was realized using “OECD QSAR APPLICATION TOOL BOX” version 2.1.2. Presented results show that both substances have common (eco)toxicological behavior (attachment).

Table 1: Data Matrix, Analogue Approach:

CAS Number			Target chemical 22984-54-9	Target chemical 34206-40-1
CHEMICAL NAME			MOS Butan-2-one O,O',O''-(methylsilylidyne)trioxime	TOS Butan-2-one O,O',O'',O'''-silanetetrayltetraoxime
PHYSICO-CHEMICAL DATA
Melting/Freezing point Point			Experimental results: Freezing point < -30 ºC. EU Method A.1 and OECD 102 (PN-ISO 1392:2002).	Experimental results: Melting point: 59.9 ºC at 102.2 kPa. EU method A.1 and OECD 102.
Boiling Point			Experimental results: Decomposition observed in the temperature range of 157.0 – 159.0 ºC. The test item decomposes below the boiling point under atmospheric pressure of 1008.3 hPa. EU method A.2 and OECD 103. Estimated by EPI-Suite MPBPWIN v 1.43: 329.15 ºC	Experimental results: Decomposition observed in the temperature range of 169-170 ºC. The test item decomposes below the boiling point under atmospheric pressure of 1008.3 hPa. EU method A.2 and OECD 103. Estimated by EPI-Suite MPBPWIN v 1.43: 329.15 ºC
Relative density			Experimental results: 0.984 at 20 ºC EU Method A.3 (CIPAC MT 3.2)	Experimental results: 1.049 at 20 ºC EU Method A.3
Vapour Pressure			Experimental results: 0.142 Pa at 25 ºC EU Method A.4 and OECD Guidance 104.	Experimental results: 0.00242 Pa at 25 ºC EU Method A.4 and OECD Guidance 104.
Partition Coefficient (log Kow)			Estimated by EPI-Suite KOWWIN v1.68: Log Kow: 9.83	Estimated by EPI-Suite KOWWIN v1.68: Log Kow: 12.08
Water solubility			Data waiving (hydrolytically unstable).	Data waiving (hydrolytically unstable).
ENVIRONMENTAL FATE and PATHWAY
Aerobic Biodegradation			Experimental results: Key study (OECD 301C; MITI 1992): Not readily biodegradable.	Experimental results: Key study (read-across): Not readily biodegradable.
ENVIRONMENTAL TOXICITY
Acute Toxicity to Fish			Experimental results: Keys study (read-across): 96h-LC50 (Pimephales promelas): 972.34 mg/L Keys study (read-across): 96h-LC50 (Oryzias lapides): >115.34 mg/L	Experimental results: Keys study (read-across): 96h-LC50 (Pimephales promelas): 901.2 mg/L Keys study (read-across): 96h-LC50 (Oryzias lapides): >106.90 mg/L
Acute Toxicity to Aquatic Invertebrates			Experimental results: Read-across: 48h-EC50 (Daphnia): 230.69 mg/L	Experimental results: Read-across: 48h-EC50 (Daphnia): 214.88 mg/L
Toxicity to Aquatic Plants			Experimental results: Keys study (read-across): 72h-EC50 (Selenastrum capricorntum): 18.45 mg/L 72h-EC50 (Selenastrum capricorntum): 3.00 mg/L	Experimental results: Keys study (read-across): 72h-EC50 (Selenastrum capricorntum): 17.1 mg/L 72h-NOEC (Selenastrum capricorntum): 2.78 mg/L
MAMMALIAN TOXICITY
Acute Toxicity: Oral			Experimental results: Keys study: LD50 = 2463 mg/kg bw (rat, male/female)	Experimental results: Keys study (read-across): LD50 = 2282.81 mg/kg bw (rat, male/female)
Acute Toxicity: Inhalation			No data.	No data.
Acute Toxicity: Dermal			Experimental results: Keys study: LD50 > 2000 mg/kg bw (rat, male/female)	Experimental results: Keys study (read-across): LD50 > 2000 mg/kg bw (rat, male/female)
Skin irritation			Experimental results: Weight of evidence: Not irritating (rabbit)	Experimental results: Weight of evidence (read-across): Not irritating (rabbit)
Eye irritation			Experimental results: Key study: Irritating (rabbit)	Experimental results: Key study (read-across): Irritating (rabbit)
Skin Sensitization			Experimental data: Key study: Sensitising	Experimental data: Key study (read-across): Sensitising
Repeated Dose Toxicity			Repeated dose toxicity oral: Experimental results: Key study (read-across): NOAEL (90 days): 28.84 mg/kg bw/day (rat, male) NOAEL (90 days): 34.60 mg/kg bw/day (rat, female)	Repeated dose toxicity oral: Experimental results: Key study (read-across): NOAEL (90 days): 26.73 mg/kg bw/day (rat, male) NOAEL (90 days): 32.07 mg/kg bw/day (rat, female)
Genetic Toxicity in vitro		Gene mutation in bacteria	Experimental results: Weight of evidence: NTP preincubation protocol (read-across): non-mutagenic inSalmonella typhimuriumTA97, TA98, or TA100 strains with and without metabolic activation, and mutagenic in TA1535 with hamster liver metabolic activation but non-mutagenic with rat liver or without metabolic activation. NTP’s dessicator procedure (read-across): non-mutagenic in TA98 and TA100 strains with or without rat or hamster liver metabolic activation. Study by Rogers-Back et al. (read-across): non-mutagenic inSalmonella typhimuriumTA98, TA100, TA1535, TA1537 and TA1538 strains with and without rat or hamster liver metabolic activation. Study by the Ministry of Health, Labour and Welfare of Japan (read-across): non-mutagenic inSalmonella typhimuriumTA100, TA1535, TA98, TA1537 and Escherichia coli WP2 uvrA with and without metabolic activation.	Experimental results: Weight of evidence: NTP preincubation protocol (read-across): non-mutagenic inSalmonella typhimuriumTA97, TA98, or TA100 strains with and without metabolic activation, and mutagenic in TA1535 with hamster liver metabolic activation but non-mutagenic with rat liver or without metabolic activation. NTP’s dessicator procedure (read-across): non-mutagenic in TA98 and TA100 strains with or without rat or hamster liver metabolic activation. Study by Rogers-Back et al. (read-across): non-mutagenic inSalmonella typhimuriumTA98, TA100, TA1535, TA1537 and TA1538 strains with and without rat or hamster liver metabolic activation. Study by the Ministry of Health, Labour and Welfare of Japan (read-across): non-mutagenic inSalmonella typhimuriumTA100, TA1535, TA98, TA1537 and Escherichia coli WP2 uvrA with and without metabolic activation.
		Chromosomal aberration	Experimental results: Key study (read-across): The substance was determined not to induce chromosomal aberrations in cultured Chinese hamster ovary cells treated with or without S9. Key study (read-across): The substance was determined not to induce neither structural chromosomal aberrations nor polyploidy in Chinese hamster lung (CHL/IU) with or without metabolic activation.	Experimental results: Key study (read-across): The substance was determined not to induce chromosomal aberrations in cultured Chinese hamster ovary cells treated with or without S9. Key study (read-across): The substance was determined not to induce neither structural chromosomal aberrations nor polyploidy in Chinese hamster lung (CHL/IU) with or without metabolic activation.
		Mammalian gene mutation	Experimental results: Key study (read-across): The substance was determined to be negative for mutagenic activity with metabolic activation and positive without metabolic activation but in the presence of cytotoxicity.	Experimental results: Key study (read-across): The substance was determined to be negative for mutagenic activity with metabolic activation and positive without metabolic activation but in the presence of cytotoxicity.
Genetic Toxicity in vivo			Experimental results: Key study (read-across): The substance was determined to be negative for in vivo cytogenicity in mammalian cells (no increase in the frequency of micronucleated normochromatic erythrocytes in the peripheral blood of male or female mice up to an estimated concentration of 11534.28 ppm for 13 weeks).	Experimental results: Key study (read-across): The substance was determined to be negative for in vivo cytogenicity in mammalian cells (no increase in the frequency of micronucleated normochromatic erythrocytes in the peripheral blood of male or female mice up to an estimated concentration of 11534.28 ppm for 13 weeks).
Reproductive Toxicity	Toxicity to reproduction		Experimental results: Key study: Two-generation study (read-across) LOAEL (parental toxicity): 11.53 mg/kg bw/day (rat, F0 and F1, male/female) (basis for effect: hematopoiesis and hemosiderosis in spleens and livers) NOAEL (reproductive and postanal toxicity): > 230.69 mg/kg bw/day (rat, F1 and F2, male/female) (basis for effect:no adverse effect observed).	Experimental results: Key study: Two-generation study (read-across) LOAEL (parental toxicity): 10.69 mg/kg bw/day (rat, F0 and F1, male/female) (basis for effect: hematopoiesis and hemosiderosis in spleens and livers) NOAEL (reproductive and postanal toxicity): >213.81 mg/kg bw/day (rat, F1 and F2, male/female) (basis for effect:no adverse effect observed).
	Developmental toxicity		Experimental results: Key study (read-across): Prenatal Developmental Toxicity Test: LOAEL (maternal toxicity): 69.21 mg/kg bw/day (rat) (basis for effect: enlarged spleens). NOAEL (developmental toxicity): > 692.06 mg/kg bw/day (rats, male/female) (basis for effect: no adverse effects)	Experimental results: Key study: Prenatal Developmental Toxicity Test (read-across): LOAEL (maternal toxicity): 64.14 mg/kg bw/day (rat) (basis for effect: enlarged spleens). NOAEL (developmental toxicity): > 641.43 mg/kg bw/day (rats, male/female) (basis for effect: no adverse effects)

Validity criteria fulfilled:

not specified

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Based on the read-across approach from experimental results on analogue substance butan-2-one O,O',O''-(methylsilylidyne)trioxime, the test item butan-2-one O,O',O'',O'''-silanetetrayltetraoxime was determined to be not readily biodegradable.

Executive summary:

The readily biodegradation test was performed by MITI according to OECD Guideline 301 C on analogue substance butan-2-one O,O',O''-(methylsilylidyne)trioxime. 30 mg/L of activated sludge were exposed for 28 days to 100 mg/L. The biodegradation was analysed by indirect analysis, BOD (NO2) and BOD (NH3) obtaining a biodegradation of 20% and 26% respectively and by direct TOC analysis obtaining a biodegradation of 28%. Based on these results, the read-across was applied and the test item butan-2-one O,O',O'',O'''-silanetetrayltetraoxime was determined to be not readily biodegradable under test conditions.

Description of key information

Key study: Based on the read-across approach from experimental results (test method OECD 301C) on the analogue substance butan-2-one O,O',O''-(methylsilylidyne)trioxime, butan-2-one O,O',O'',O'''-silanetetrayltetraoxime was determined to be not readily biodegradable.

Supporting study: EPI-Suite v4.1 (BIOWIN v4.10), butan-2-one O,O',O'',O'''-silanetetrayltetraoxime was predicted to not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Additional information

Key study: Read-across from experimental data on analogue butan-2-one O,O',O''-(methylsilanetriyl)oxime:

A readily biodegradation test was performed by MITI according to OECD Guideline 301 C on analogue substance butan-2-one O,O',O''-(methylsilylidyne)trioxime. 30 mg/L of activated sludge were exposed for 28 days to 100 mg/L. The biodegradation was analysed by indirect analysis, BOD (NO2) and BOD (NH3) obtaining a biodegradation of 20% and 26% respectively and by direct TOC analysis obtaining a biodegradation of 28%. Based on these results, the read-across was applied and the test item butan-2-one O,O',O'',O'''-silanetetrayltetraoxime was determined to be not readily biodegradable under test conditions.

 

Supporting study: According the the calculation method EPI-Suite, EPA (USA) / BIOWIN v4.10, butan-2-one O,O',O'',O'''-silanetetrayltetraoxime was predicted to not readily biodegradable.