Oct-2-ene

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP Unknown, guideline study minor restrictions in design and/or reporting but otherwise considered adequate for assessment

Justification for type of information:

Read-across between the target substance Oct-2-ene (EC 203-894-2 / CAS 111-67-1) and source substance Alkenes, C6-8-branched, C7-rich (EC 307-298-4 / CAS 97592-99-9) is based upon the similarity of the chemical structures and their respective physico-chemical properties. The ECHA Read-Across Assessment Framework (RAAF) states that substances with qualitatively similar properties can form the basis of read-across in circumstances where the source and target substances share such similar characteristics.
Target substance Oct-2-ene and source substance Alkenes, C6-8-branched, C7-rich are mono-constituent and UVCB olefins, respectively. Structurally, the differences between source and target substances include: 1) the length of the carbon chain (uniformly eight for the target substance, but variably six to eight for the source substance); 2) the position of the carbon-carbon double bond (uniformly at the C2 position for the target substance, but variable for the source substance); and 3) the degree of branching (the target substance is a linear, non-branched structure, whereas branching in the source substance is variable).
The target and source substances both fit within the boundaries of chemical category of higher olefins. Studies conducted by the HOPA consortium on a large range of higher olefin category members (including Alkenes, C6-8-branched, C7-rich) demonstrated sufficiently similar physico-chemical, environmental fate and toxicological properties to substantiate the basis for read-across; category members in the C6-C10 range may be moderately toxic to highly toxic to aquatic organisms and environmental toxicity is expected to be manifested as non-polar narcosis. Therefore, Oct-2-ene (which falls within the C6-C10 range) is expected to behave similarly. Justification for inclusion of Oct-2-ene within the boundaries of the higher olefins category, and the relevance of each category member as an analogue substance to Oct-2-ene, is provided in Section 13 (Document name: “HOPA Higher Olefins CJD with Category Matrix Report [rev 1 Sept 2016]”; Document name: "ACC Product Stewardship Summary for Higher Olefins Category (2008-12-03)”).

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
not applicable

Oxygen conditions:

aerobic

Inoculum or test system:

not specified

Details on inoculum:

Micro organisms obtained from Sittingbourne sewage works

Duration of test (contact time):

28 d

Initial conc.:

2 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Test substance olefins 68 PQ 11 aded to test medium from stock solution containing 2.4 g/l emulsified in Dobane PT sulphonate. Final test concentration was 2 mg/l olefins 68 PQ 11. Duplicate bottles incubated at 21 + 1 degrees C. Extent of biodegradation determined by measuring oxygen concentration in the bottles at 5, 15, and 28 days.

Reference substance:

benzoic acid, sodium salt

Preliminary study:

data not reported

Test performance:

data not reported

Key result

Parameter:

other: %ThOD

Value:

> 41 - < 42

Sampling time:

28 d

Details on results:

sodium benzoate had reached >60% degradation by day 15.

Results with reference substance:

sodium benzoate had reached >60% degradation by day 15.

Validity criteria fulfilled:

yes

Conclusions:

The test substance was not found to be readily biodegradable under the conditions of the test.

Executive summary:

This study followed standard guidelines and was conducted to GLP. It is therefore considered suitable for use in this assessment.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

weight of evidence

Study period:

22 feb 1995 - 24 mar 1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP compliant, guideline study, available as unpublished report, limitations in reporting but otherwise adequate for assessment.

Justification for type of information:

Read-across between the target substance Oct-2-ene (EC 203-894-2 / CAS 111-67-1) and source substance 1-Decene (EC 212-819-2/ CAS 872-05-9) is based upon the similarity of the chemical structures and their respective physico-chemical properties. The ECHA Read-Across Assessment Framework (RAAF) states that substances with qualitatively similar properties can form the basis of read-across in circumstances where the source and target substances share such similar characteristics.
Target substance Oct-2-ene and source substance 1-Decene are each mono-constituent linear olefins. Structurally, the differences between source and target substances include: 1) the length of the carbon chain (eight for the target substance, and ten for the source substance); and 2) the location of the carbon-carbon double bond (uniformly at the C2 position for the target substance, but uniformly at the C1 terminal position for the source substance).
The target and source substances both fit within the boundaries of chemical category of higher olefins. Studies conducted by the HOPA consortium on a large range of higher olefin category members (including 1-Decene) demonstrated sufficiently similar physico-chemical, environmental fate and toxicological properties to substantiate the basis for read-across; category members in the C6-C10 range may be moderately toxic to highly toxic to aquatic organisms and environmental toxicity is expected to be manifested as non-polar narcosis. Therefore Oct-2-ene (which falls within the C6-C10 range) is expected to behave similarly. Justification for inclusion of Oct-2-ene within the boundaries of the higher olefins category, and the relevance of each category member as an analogue substance to Oct-2-ene, is provided in Section 13 (Document name: “HOPA Higher Olefins CJD with Category Matrix Report [rev 1 Sept 2016]”; Document name: "ACC Product Stewardship Summary for Higher Olefins Category (2008-12-03)”).

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

GLP compliance:

yes

Remarks:

No certificate

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
data not reported

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

obtained from the aeration basin of the municipal water treatment plant, Novara, Italy. Sludge aerated at room temperature for 24 hours prior to the test.

Duration of test (contact time):

28 d

Initial conc.:

18.6 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Inoculum concentration of 30mg/l suspended solids. Test conducted at 22±0.2°C. As the test substance is insoluble in water itwas added directly to the test flasks by a microsyringe. Duplicate test and blank controls were run and the oxygen consumption measured daily.

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

> 80.8 - < 80.9

Sampling time:

28 d

Results with reference substance:

Reference substance showed 88% biodegradation after 28 days.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test substance was shown to be readily biodegradable in an OECD 301F.

Executive summary:

This GLP study was conducted to standard guidelines. The analytical method used to determine oxygen consumption is not stated in the report. Despite this limitation the validity criteria of the test are met and so this study is considered suitable for use as. n-decene therefore is considered readily biodegradable as a mean of 80.8% degraded within 28 days.

Reference 3

Endpoint:

biodegradation in water: screening test, other

Remarks:

QSAR prediction

Type of information:

(Q)SAR

Remarks:

QSAR BIOWINv4.10

Adequacy of study:

weight of evidence

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

Justification for type of information:

Modeling report of BIOWIN v4.10, a model contained within EPI-Suite version 4.1, a reliable QSAR model.

Qualifier:

no guideline followed

Principles of method if other than guideline:

BIOWIN v4.10 a model with U.S. EPA's EPI-Suite, a reliable QSAR model included in the OECD QSAR Toolbox.

Parameter followed for biodegradation estimation:

other:

Remarks:

(Q)SAR Model biodegradation prediction.

Key result

Parameter:

other:

Remarks:

ultimate biodegradation timeframr

Value:

3.548

Remarks on result:

readily biodegradable based on QSAR/QSPR prediction

Remarks:

BIOWIN3 and BIOWIN5 values

Key result

Parameter:

probability of ready biodegradability (QSAR/QSPR)

Value:

0.589

Remarks on result:

readily biodegradable based on QSAR/QSPR prediction

Remarks:

BIOWIN3 and BIOWIN5 values

Biowin1 (Linear Model Prediction)   : Biodegrades Fast

Biowin2 (Non-Linear Model Prediction): Biodegrades Fast

Biowin3 (Ultimate Biodegradation Timeframe): Days-Weeks

Biowin4 (Primary Biodegradation Timeframe): Days

Biowin5 (MITI Linear Model Prediction)   : Biodegrades Fast

Biowin6 (MITI Non-Linear Model Prediction): Biodegrades Fast

Biowin7 (Anaerobic Model Prediction): Does Not Biodegrade Fast

Ready Biodegradability Prediction: YES

 

Criteria for the YES or NO prediction: If the Biowin3 (ultimate survey

 model) result is "weeks" or faster (i.e. "days", "days to weeks", or

 "weeks" AND the Biowin5 (MITI linear model) probability is >= 0.5, then

 the prediction is YES (readily biodegradable). If this condition is not

 satisfied, the prediction is NO (not readily biodegradable). This method

 is based on application of Bayesian analysis to ready biodegradation data. 

Validity criteria fulfilled:

yes

Remarks:

Validated QSAR, part of the OECD (Q)SAR Toolbox.

Interpretation of results:

readily biodegradable

Conclusions:

The BIOWIN v4.10 model predicted that the substance is readily biodegradable; the overall prediction was based upon the results from the BIOWIN3 and BIOWIN5 modules. The BIOWIN1 value =0.9110 and the BIOWIN2 value = 0.9940 were both greater than 0.5 and indicated fast biodegradation. The BIOWIN3 value = 3.5479 indicated a timeframe of days to weeks to ultimate biodegradation, and the BIOWIN4 value of 4.2240 indicated a timeframe of days to primary degradation. The BIOWIN5 value = 0.5892 and the BIOWIN6 value = 0.7503 were both greater than 0.5, and both indicated the substance is readily biodegradable. The BIOWIN7 value of -0.0016 was less than 0.5, and indicated that it does not biodegrade fast under anaerobic conditions.

Description of key information

Ready biodegradability tests were conducted on two analogue substances. Although one analogue substance did not exhibit ready biodegradability in a CO₂ evolution test, a degradation rate of >41% and <42% in 28 days was observed; in accordance with ECHA guidance, the observed degradation rate is evidence of inherent, primary degradability (i.e., degradation of 20% or more in a biodegradability assay) and significant mineralisation (>40% degradation in a ready biodegradability test). A second analogue substance exhibited ready biodegradability in a manometric respirometry test, with an observed degradation rate of >80.8 and <80.9% in 28 days. Additionally, a validated QSAR model (EPI Suite BIOWIN 4.10) predicted that the substance is readily biodegradable, based on two modules within the model: BIOWIN 3, which predicted ultimate degradation of the substance in the timeframe of “days-weeks”; and BIOWIN 5, which predicted that the substance “biodegrades fast”. Three additional modules within the model (BIOWIN 1, BIOWIN 2, BIOWIN 5 and BIOWIN 6) predicted that the substance “biodegrades fast”; one module (BIOWIN 4) predicted that primary degradation occurs within the timeframe of “days”. Thus, the inherent biodegradability of the substance is supported by three lines of evidence: an analogue of the substance exhibited inherent, primary degradability and significant mineralisation in a CO₂ evolution test; another analogue exhibited ready biodegradability in a manometric respirometry test; and the substance itself is not refractory to ultimate degradation as indicated by QSAR predictions based on its structural components. Therefore, the substance was determined to exhibit inherent biodegradability, with significant mineralisation expected in the environment.

 

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater