Trifluoro(trifluoromethoxy)ethylene

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

Justification for type of information:

QMRF and QPRF are attached

Guideline:

other: REACH guidance on QSARs R.6

Principles of method if other than guideline:

 BIOWIN estimates the probability of rapid aerobic and anaerobic biodegradation of an organic compound in the presence of mixed populations of environmental microorganisms.  BIOWIN contains seven separate models:
 Biowin1  =  linear probability model
 Biowin2 =  nonlinear probability model
 Biowin3  =  expert survey ultimate biodegradation model
 Biowin4  =  expert survey primary biodegradation model
 Biowin5  =  MITI linear model
 Biowin6  =  MITI nonlinear model
 Biowin7  =  anaerobic biodegradation model
Biowin 1 and 2, are intended to convey a general indication of biodegradability under aerobic conditions, and not for any particular medium.  
Biowin3 and 4 yield estimates for the time required to achieve complete ultimate and primary biodegradation in a typical or "evaluative" aquatic environment.
Biowin5 and 6 are predictive models for assessing a compound’s biodegradability in the Japanese MITI (Ministry of International Trade and Industry) ready biodegradation test; i.e. OECD 301C.
Biowin7, the anaerobic biodegradation model, predicts probability of rapid degradation in the "serum bottle" anaerobic biodegradation screening test.

GLP compliance:

no

Specific details on test material used for the study:

SMILE: FC(F)(F)OC(F)=C(F)F

Oxygen conditions:

other: not applicable

Inoculum or test system:

other: not applicable

Details on inoculum:

Not applicable.

Initial conc.:

other: not applicable

Based on:

other: not applicable

Parameter followed for biodegradation estimation:

not specified

Details on study design:

not applicable

Reference substance:

not required

Preliminary study:

not applicable

Test performance:

not applicable

Parameter:

other: QSAR prediction

Remarks on result:

other: not readily biodegradable

Details on results:

The QSAR did not provide a % degradation prediction.

Biodegradability estimates are based upon fragment constants that were developed using multiple linear or non-linear regression analyses, depending on the model.

Experimental biodegradation data were used to generate the Syracuse Research Corporation's (SRC) dataset for the models Biowin 1 and 2. The evaluated dataset was used to select chemical fragments with a potential effect on biodegradability.

These two models Biowin 3 and Biowin 4 estimate the time required for "complete" ultimate and primary biodegradation. Primary biodegradation is the transformation of a parent compound to an initial metabolite. Ultimate biodegradation is the transformation of a parent compound to carbon dioxide and water, mineral oxides of any other elements present in the test compound, and new cell material

Biowin5 and 6 are predictive models for assessing a compound's biodegradability in the Japanese MITI (Ministry of International Trade and Industry) ready biodegradation test; i.e. OECD 301C.  These models use an approach similar to that used to develop Biowin1 and 2.

Biowin7, the anaerobic biodegradation model, is the most recent.  As for the other Biowin models, multiple (linear) regression against molecular fragments was used to develop the model, which predicts probability of rapid degradation in the "serum bottle" anaerobic biodegradation screening test.

Validity criteria fulfilled:

not applicable

Interpretation of results:

not readily biodegradable

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Description of key information

No experimental data on PMVE biodegradation in water are available. In fact, on the grounds of the physico-chemical properties and environmental fate assessments of the substance, no significant exposure of the aquatic environment is expected. Moreover the substance profile itself indicates the difficulty to properly test PMVE and provide meaningful results of its biodegradation in aqueous systems. Nevertheless, in order to evaluate the biodegradation potential of PMVE, the BIOWIN v.4.10 model has been applied. The prediction obtained from the model suggests that PMVE is not ready biodegradable.

Additional information

On the grounds of the physico-chemical properties of PMVE (Boiling point of -26 °C, slight water solubility, high Henry Law Constant, low Kow, low Koc) and the results on environmental fate obtained from EQC Fugacity III Model (Version 2.02, The Canadian Centre for Environmental Modelling and Chemistry, May 2003), the substance is expected to primarily and rapidly partition to the atmosphere. No exposure to the aquatic environment is consequently expected.

The substance profile itself indicates the difficulty to properly test PMVE and provide meaningful results of its biodegradation in aqueous systems as well as in sediment and soil. Nevertheless a further assessment based on Quantitative Structure Activity Relationships (QSARs) has been however applied.

The prediction of the BIOWINv.4.10model(EPI Suite v.4.0)suggests that PMVE is not ready biodegradable.