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

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: sediment simulation testing

Type of information:

calculation (if not (Q)SAR)

Remarks:

Assessment (EUSES v2.0.3) supporting de minimis exposure in soil and sediment compartments.Assessment is part of a weight of evidence supporting that simulation testing is not necessary (nor technically feasible) for these compartments

Adequacy of study:

weight of evidence

Study period:

05/01/2022

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:

EUSES Model (v2.0.3)

Justification for type of information:

A consideration for testing requirements (Annex VIII, IX, column 2) is the potential for de minimis exposure. Specificall,the REACH legislation states, "Further degradation testing shall be considered if the chemical safety assessment according to Annex I indicates the need to investigate further the degradation of the substance." In this case, a risk which is considerably low (e.g., RCR << 1) would indicate NO further need to investigate further, and as such, that testing is not required for the compartment of interest.

The EUSES model was developed and validated for the quantitative environmental risk assessment of organic chemicals and is widely used for chemical registration and risk assessment. Its validity and relevance are well-established within the REACh guidance.

Qualifier:

no guideline required

Principles of method if other than guideline:

Section 3 of the revised Annex XI gives a possibility to omit certain information requirements based on an exposure scenario(s) developed as a part of a CSA. It can be applied starting from Annex VIII requirements (substances imported or produced starting at 10 t/y) with the following conditions: Testing according to Annex VIII (only sections 8.6 and 8.7), Annex IX and Annex X may be omitted, based on exposure scenario(s) developed in the Chemical Safety Report. In all cases, adequate justification and documentation shall be provided. The justification shall be based on an exposure assessment in accordance with section 5 of Annex I and be consistent with the criteria a) to c) of section 3.2 of Annex XI

These requirements are related to the use of exposure information, alone, as a sole justification for adaptation of an endpoint or testing requirement. This information is used as a line of evidence, within a Weight of Evidence assessment. As such, while the assessment may not meet all of the provisions laid out in section 3.2 of Annex XI, it is considered, for the purpose of a WoE assessment (Annex XI, Sec 1.2) to be adequate and sufficient.

GLP compliance:

not specified

Details on source and properties of sediment:

N/A

Compartment:

sediment

Remarks on result:

not measured/tested

Remarks:

Exposure assessment focuses on the estimated risk quotients for the compartment, and not the quantitative primary half-lives and/or metabolic pathways. These are addressed in their respective weight of evidence records within sections 5.2.2. and 5.2.3.)

Transformation products:

not specified

Remarks:

Exposure assessment (for assessment and identification of metabolites see Catalogic QSAR record in 5.2.2. and 5.2.3 of IU).

Conclusions:

The exposure assessment indicates that exposures and risks to freshwater/marine sediment and terrestrial soil systems are sufficiently low (RCRs < 0.1). As such, criteria a) to c) of section 3.2 of Annex XI are fulfilled and no further testing for these compartments is justified.

Executive summary:

The exposure assessment indicates that exposures and risks to freshwater/marine sediment and terrestrial soil systems are sufficiently low (RCRs < 0.1). As such, criteria a) to c) of section 3.2 of Annex XI are fulfilled and no further testing for these compartments is justified.

Reference 2

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

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 1.2 a weight of evidence approach is taken. One relevant line of evidence for fulfilling the information requirement, as well as Annex XIII persistence assessment requirements includes valid 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, Intermedia Extrapolation Factors between water, soil, sediment (Boethling et al., 1995)
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Attached justification'

Compartment:

natural sediment

DT50:

>= 28 - <= 112 d

Type:

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

Temp.:

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") in surface water systems. These vaues were extrapolated to the sediment compartment, using a 4:1 extrapolation factor, as described by Boetheling et al., 1995 (US EPA). The susbtances had ultimate biodegradation predictions in surface waterwhich ranged from weeks (< 28d) to months (> 60d) with 11 of 14 constituents < 60d (ultimate degradation).

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 primary and ultimate degradability predicted for the representative constituents as well as 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 water: sediment 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 1.2 a weight of evidence approach is taken. One relevant line of evidence for fulfilling the information requirement, as well as Annex XIII persistence assessment requirements includes valid 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

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'

Compartment:

sediment

DT50:

>= 4 - <= 25.16 d

Temp.:

20 °C

Remarks on result:

other:

Remarks:

Calculated degradation half-lives for constituents of this substance range between < 4.0 and 25.2 days. For intermedia extrapolation from water to sediment, a ratio of 4:1 (Boetheling et al., 1995) was used, however, it should be noted that even using the 1:9 ratio which is the defauly assumption in the MacKay Level 3 fugacity model, the range of predicted half-lives is still below the P/vP criteria of 180d for sediment 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 properties 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 relationships 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 assessment, the substance has been assessed using a combination of QSAR predictions, experimental 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 4

Endpoint:

biodegradation in water: sediment 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 1.2 a weight of evidence approach is taken. One relevant line of evidence for fulfilling the information requirement, as well as Annex XIII persistence assessment requirements includes valid 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'

Compartment:

water

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.

Reference 5

Endpoint:

biodegradation in water and sediment: simulation testing, other

Remarks:

readily biodegradation data on whole substance and representative constituents for inclusion in weight of evidence assessment

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Reason / purpose for cross-reference:

reference to other study

Reason / purpose for cross-reference:

reference to other study

Reason / purpose for cross-reference:

reference to other study

Reason / purpose for cross-reference:

reference to other study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

other: OECD 301D, F

Deviations:

not specified

GLP compliance:

not specified

Remarks:

Studies on the registered substance and the alcohol constituents ARE GLP (with certification).

Inoculum or test system:

activated sludge (adaptation not specified)

Remarks on result:

other: Assessment of Simulation WoE Data

Remarks:

In a standard OECD 301F test using non-adapted inoculum from a domestic wastewater treatment facility, 33% degradation was achieved at 28d. The substance was loaded into each replicate flask at a relatively high concentration of 40 mg/L, equivalent to 124 mg ThOD/L. In a second OECD 301F test, again using a relatively high concentration of 50 mg/L, equivalent to 152 mg ThOD/L, 42% degradation was achieved at 28d, and reached 51% by day 60 using non-adapted inoculum from domestic wastewater treatment facility. This inoculum was collected and mixed with supernatant obtained from a petrochemical-contaminated soil sample. Using that combined, pre-adapted inoculum in the 301F test system, 63% biodegradation was achieved in 28d, and continued to degrade to 82% in 60d. The significant mineralization levels attained in the test using non-adapted inoculum (33% to 51%), considering potential issues of bioavailability due to solubility limits, along with the extensive level of ultimate (complete mineralization) biodegradation when using pre-exposed inocula, was considered further evidence of a lack of persistence in the environment. Experimental biodegradation screening data (OECD 301 studies) are available for 2 of the selected representative constituents of the test substance. Additionally, data is available for an analogue substances forthe acetal sub-class of constituents. Results from several 301 studies indicate high (83 - 97.5%) biodegradability for these constituents at 28d. Given the rapid degradability of the analogue alcohols and acetal compounds within the guideline 301 studies, constituents of these two ee groups are considered to be readily degradable and by extension, not P or vP.

Transformation products:

not specified

Remarks:

this line of evidence does not allow for metabolite identification. For a model evaluation of potential metabolites and their properties see the Catalogic assessment / line of evidence.

Conclusions:

In a standard OECD 301F test using non-adapted inoculum from a domestic wastewater treatment facility, 33% degradation was achieved at 28d. The substance was loaded into each replicate flask at a relatively high concentration of 40 mg/L, equivalent to 124 mg ThOD/L. In a second OECD 301F test, again using a relatively high concentration of 50 mg/L, equivalent to 152 mg ThOD/L, 42% degradation was achieved at 28d, and reached 51% by day 60 using non-adapted inoculum from domestic wastewater treatment facility. This inoculum was collected and mixed with supernatant obtained from a petrochemical-contaminated soil sample. Using that combined, pre-adapted inoculum in the 301F test system, 63% biodegradation was achieved in 28d, and continued to degrade to 82% in 60d. The significant mineralization levels attained in the test using non-adapted inoculum (33% to 51%), considering potential issues of bioavailability due to solubility limits, along with the extensive level of ultimate (complete mineralization) biodegradation when using pre-exposed inocula, was considered further evidence of a lack of persistence in the environment. Experimental biodegradation screening data (OECD 301 studies) are available for 2 of the selected representative constituents of the test substance. Additionally, data is available for an analogue substances forthe acetal sub-class of constituents. Results from several 301 studies indicate high (83 - 97.5%) biodegradability for these constituents at 28d. Given the rapid degradability of the analogue alcohols and acetal compounds within the guideline 301 studies, constituents of these two ee groups are considered to be readily degradable and by extension, not P or vP.

Executive summary:

In a standard OECD 301F test using non-adapted inoculum from a domestic wastewater treatment facility, 33% degradation was achieved at 28d. The substance was loaded into each replicate flask at a relatively high concentration of 40 mg/L, equivalent to 124 mg ThOD/L. In a second OECD 301F test, again using a relatively high concentration of 50 mg/L, equivalent to 152 mg ThOD/L, 42% degradation was achieved at 28d, and reached 51% by day 60 using non-adapted inoculum from domestic wastewater treatment facility. This inoculum was collected and mixed with supernatant obtained from a petrochemical-contaminated soil sample. Using that combined, pre-adapted inoculum in the 301F test system, 63% biodegradation was achieved in 28d, and continued to degrade to 82% in 60d. The significant  mineralization levels attained in the test using non-adapted inoculum (33% to 51%), considering potential issues of bioavailability due to solubility limits, along with the extensive level of ultimate (complete mineralization) biodegradation when using pre-exposed inocula, was considered  further evidence of a lack of persistence in the environment.  Experimental biodegradation screening data (OECD 301 studies) are available for 2 of the selected representative constituents of the test substance. Additionally,  data is available for an analogue substances forthe acetal sub-class of constituents. Results from several 301 studies indicate high (83 - 97.5%) biodegradability for these constituents at 28d. Given the rapid degradability of the analogue alcohols and acetal compounds within the guideline 301 studies, constituents of these two ee groups are considered to be readily degradable and by extension, not P or vP.

Reference 6

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

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 1.2 a weight of evidence approach is taken. One relevant line of evidence for fulfilling the information requirement, as well as Annex XIII persistence assessment requirements includes valid 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'

Compartment:

water

DT50:

>= 7 - <= 28 d

Type:

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

Temp.:

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:

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 primary and ultimate degradability predicted for the representative constituents as well as 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 7

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

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 1.2 a weight of evidence approach is taken. One relevant line of evidence for fulfilling the information requirement, as well as Annex XIII persistence assessment requirements includes valid 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'

Compartment:

water

DT50:

>= 1 - <= 6.29 d

Temp.:

20 °C

Remarks on result:

other:

Remarks:

Calculated degradation half-lives for constituents of this substance range between < 1.0 and 6.29 days. 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 properties 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 relationships 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 assessment, the substance has been assessed using a combination of QSAR predictions, experimental 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) . For full summary of predicted half-lives see attached QPRF report.

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 8

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

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 1.2 a weight of evidence approach is taken. One relevant line of evidence for fulfilling the information requirement, as well as Annex XIII persistence assessment requirements includes valid 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'

Compartment:

water

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).