Alkenes, C6-11 (branched), hydroformylation products, distn. residues, heavy cracked fraction

Biodegradation in soil

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in soil: simulation testing

Type of information:

(Q)SAR

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:

Standard simulation biodegradation studies are not possible for petroleum-derived UVCB substances, therefore in accordance with Annex XI Section 1.3 testing is not scientifically necessary and the e ndpoint has been fulfilled using QSAR calculations for relevant constituents. Full justifications for this QSAR are presented in 'Attached justification', but in brief these are justified because:
- the results are obtained from a QSAR model whose scientific validity has been established
- Identified substance constituents fall within the applicability domain of the QSAR model
- results are adequate for the purposes of risk assessment
- adequate and reliable documentation is provided

Qualifier:

no guideline required

Principles of method if other than guideline:

- Software tool(s) used including version: OASIS CATALOGIC v5.11.19
- Model(s) used: CATALOGIC Kinetic 301F v.13.16
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Attached justification'

DT50:

>= 1 - <= 6.29 d

Temp.:

ca. 20 °C

Remarks on result:

other:

Remarks:

Calculated degradation half-lives for constituents of this substance range between < 1.0 and 6.29 days. For intermedia extrapolation from water to soil, a ratio of 1:1 (Boetheling et al., 1995) was used, however, it should be noted that even using the 1:2 or 1:4 ratios which are default assumptions in the MacKay Level 3 fugacity model and other models, the range of predicted half-lives is still below the P/vP criteria of 120d and 180d for soil systems. Additionally, It should be borne in mind that this is the full range of predicted values, and that this may be misleading or unrepresentative of the prop erties of the UVCB substance as a whole. The range should therefore be treated with caution and not taken out of context. Standard simulation studies for this endpoint are intended for monoconstituent substances and are not possible for this complex substance. However, this endpoint is characterised using quantitative structure property relationsh ips for representative structures that adequately cover the composition of the UVCB substance used to assess the environmental hazard and risk of this substance. For purposes of PBT asses sment, the substance has been assessed using a combination of QSAR predictions, experiment al testing, and weight of evidence for representative constituents using a mixture of the "known constituent" and "whole substance" approaches (as recommended in REACH guidance Section R.11.1.4.2) .

Transformation products:

not measured

Remarks:

transformation products and their abundence estimated using OASIS CATALOGIC 301F Kinetic model QSAR (see attached document for detailed assessment)

Details on transformation products:

Detailed information including representative structures, phys-chem properties, estimated quantities, and QSAR predictions of primary and ultimate degradation of the identified metabolites as well as an assessment of their PBT and vPvB potential is contained in the file "Metabolite ID and PBT Assessment.pdf" and is attached in "Attached Background Material" below.

Conclusions:

Given the ultimate degradability predicted for the parent constituents and identified metabolites as well as the quantiative predictions of compartmental primary half-lives in water, soil, and sediment compartments, it is concluded that the substance and its constituents are not persistent, and as such simulation studies in soil or sediment are not required and will not provide additional information as to the PBT/vPvB properties of the substance.

Reference 2

Endpoint:

biodegradation in soil: simulation testing

Type of information:

(Q)SAR

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:

Standard simulation biodegradation studies are not possible for petroleum-derived UVCB substances, therefore in accordance with Annex XI Section 1.3 testing is not scientifically necessary and the e ndpoint has been fulfilled using QSAR calculations for relevant constituents. Full justifications for this QSAR are presented in 'Attached justification', but in brief these are justified because:
- the results are obtained from a QSAR model whose scientific validity has been established
- Identified substance constituents fall within the applicability domain of the QSAR model
- results are adequate for the purposes of risk assessment
- adequate and reliable documentation is provided

Qualifier:

no guideline required

Principles of method if other than guideline:

- Software tool(s) used including version: EPI Suite v4.11
- Model(s) used: BioWin v4.10
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Attached justification'

DT50:

>= 7 - <= 28 d

Type:

(pseudo-)first order (= half-life)

Temp.:

ca. 20 °C

Remarks on result:

other: Remark on Calculation(s)

Remarks:

Primary half-lives are predicted catagorically by the BioWin 4 model. Representative constituents for the registered substance had predicted primary half-lives of <= 7 days to <= 28 days (BioWin predictions equivalent to "days" to "days - weeks"). The susbtances had ultimate biodegradation predictions which ranged from weeks (< 28d) to months (> 60d) with 11 of 14 constituents < 60d (ultimate degradation).

Transformation products:

not measured

Remarks:

not measured transformation products and their abundence are estimated separately using OASIS CATALOGIC 301F Kinetic model QSAR. These results are summarized in the Catalogic QSAR record (sec 5.2.2) as part of the total weight of evidence assessment.

Conclusions:

Given the ultimate degradability predicted for the parent constituents and identified metabolites as well as the quantiative predictions of compartmental primary half-lives in water, soil, and sediment compartments, it is concluded that the substance and its constituents are not persistent, and as such simulation studies in soil or sediment are not required and will not provide additional information as to the PBT/vPvB properties of the substance.

Reference 3

Endpoint:

biodegradation in soil: simulation testing

Type of information:

(Q)SAR

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:

Standard simulation biodegradation studies are not possible for petroleum-derived UVCB substances, therefore in accordance with Annex XI Section 1.3 testing is not scientifically necessary and the e ndpoint has been fulfilled using QSAR calculations for relevant constituents. Full justifications for this QSAR are presented in 'Attached justification', but in brief these are justified because:
- the results are obtained from a QSAR model whose scientific validity has been established
- Identified substance constituents fall within the applicability domain of the QSAR model
- results are adequate for the purposes of risk assessment
- adequate and reliable documentation is provided

Qualifier:

no guideline required

Principles of method if other than guideline:

- Software tool(s) used including version: EAWAG BBD-PPS (2022)
- Model(s) used: Aerobic Microbial Pathway Predictor
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Attached justification'

Remarks on result:

not measured/tested

Remarks:

The model provides a qualitative metabolic pathway prediction for the relevant constituents of the registered substance. The model additionally provides a categorical assessment of the plausibility of individual reaction pathways and processes. It does not, however, provide a quantitative estimate for DT50 values in surface water, soil, or sediment compartments. As such, this model is considered to be a line of evidence which supplements the quantitative predictions (and corroborates the metabolic pathway predictions) of the Catalogic 301Fk model as well as supports experimental 301 data for the registered substance and its representative constituents.

Transformation products:

not measured

Remarks:

transformation products and their abundence are estimated separately using OASIS CATALOGIC 301F Kinetic model QSAR. These results are summarized in the Catalogic QSAR record (sec 5.2.2) as part of the total weight of evidence assessment.

Conclusions:

Given the predicted metabolic pathways for the representative constituents as well as quantiative predictions of compartmental primary half-lives in water, soil, and sediment compartments from other lines of evidence, it is concluded that the substance and its constituents are not persistent, and as such simulation studies in soil or sediment are not required and will not provide additional information as to the PBT/vPvB properties of the substance.

Description of key information

The test substance is a UVCB stream with a distribution of carbon chain lengths, functional groups, and isomeric structures. Standard guideline studies forsimulation testing on ultimate degradation are not technically feasible for UVCBs due to limitations around:
o  Radiolabeling of parent material(s)
o  Inability to analytically isolate, detect, and quantify specific structures (and associated metabolites)
o  Adequacy and relevance of guideline test system(s) for highly hydrophobic and/or volatile substances.

Due to these limitations, the relevance & reliability of the guideline studies and the confidence of their outcomes for test materials cannot be established. As such, an alternative means of fulfilling the annex VIII and IX information requirements for primary biodegradation in surface water, soil, and sediment is needed. A weight of evidence (WoE) approach is considered to be the most robust and scientifically appropriate method for addressing the REACh data requirement for the registered substance. The lines of evidence and data collected, as well as additional information to be gathered are outlined in the justification and WoE Assessment document attached
As such, testing is not scientifically necessary per Annex XI, Section 1.2 of the REACH regulation on the following basis:
·        There is sufficient weight of evidence when information from several independent sources together enable, through a reasoned justification, a conclusion on the information requirement, while the information from each single source alone is insufficient to fulfil the information requirement.
·        The justification provided adequately addressed the information that would otherwise be obtained from the study that shall normally be performed for this information requirement.
 
The registrant has prepared a weight of evidence assessment, in accordance with Annex XI Section 1.2 and the associated REACH guidance (REACH Practical Guide: How to use alternatives to animal testing (2016),How to prepare reigistration and PPORD dossiers (2021)) utilizing ECHA’s template forWeight of evidence / uncertainty in hazard assessment. The weight of evidence approach includes the use of experimental biodegradation data (OECD 301 data on the registered substance, representative constituents, and a relevant analogue substance), validated (Q)SAR models (CATALOGIC, BIOWIN), expert judgement & biological plausibility models (e.g., EAWAG BBD-PPS model), and exposure-based considerations for soil & sediment compartments to fulfill the Annex IX information requirements as well as to conclude on the potential persistence properties (Annex XIII).