Hydrocarbons, C10, aromatics, >1% naphthalene

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

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

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

The Concawe report (see cross-reference) provides freshwater and marine water experimental
primary biodegradation half-lives for hydrocarbons relevant to petroleum substances. These experimental data are all referenced in the document and have been obtained from reliable sources, including including peer-reviewed studies.

Principles of method if other than guideline:

Over 1,000 data points for hydrocarbons relevant to petroleum substances are available for freshwater and marine water experimental primary biodegradation half-lives. Concawe collected and evaluated data from these studies carried out since Howard et al. (2005) published the BioHCwin model. BioHCwin was based on collated degradation data available at the time, based on an extensive literature review. The experimental data discussed in this report represents a large fraction of new aquatic degradation data that has become available since 2005, and was therefore not used in the training set for BioHCwin. This report represents a significant expansion of experimental data for petroleum hydrocarbon constituents, including marine and freshwater biodegradation half-lives from 14 different sources, including peer-reviewed studies.

GLP compliance:

not specified

Remarks:

Data compiled within the CONCAWE report have been collected from 14 individual primary literature sources. The quality of these studies has been assessed and found to be reliable, however it is not possible to evaluate GLP compliance at present.

Inoculum or test system:

natural water

Remarks:

Natural freshwater and marine water inoculum were used in freshwater and marine experiments summarized in the CONCAWE report.

Compartment:

natural water: marine

DT50:

>= 0.48 - <= 3 d

Remarks on result:

other: Experimental data available for 5 individual constituents

Compartment:

natural water: freshwater

DT50:

>= 1.4 - <= 11.8 d

Remarks on result:

other: Experimental data available for 26 individual constituents.

Transformation products:

not measured

Remarks:

Predicted transformation products (and subsequent assessment for PBT / vPvB properties) were identified (CATALOGIC) for the range of potential constituents using the PetroRisk v7.04 product library. See attachments in QSAR endpoint(s).

Conclusions:

Freshwater half-lives are available for 26 constituents and range from 1.4 - 11.8 d , marine water half-lives are available for 5 constituents and range from 0.5 to 3 d. No constituents were identified to exceed the half-life criteria in freshwater or marine water for persistence (40, 60d, respectively). As a result, it is concluded that representative constituents within the substance are easily degraded in the environment and are not be considered to be persistent.

Executive summary:

The Concawe report provides experimental freshwater and marine primary biodegradation half-lives for petroleum substances from reliable sources, including peer-reviewed studies. Freshwater half-lives are available for 26 constituents and range from 1.4 - 11.8 d, marine water half-lives are available for 5 constituents and range from 0.5 to 3 d.

No constituents were identified to exceed the half-life criteria in freshwater or marine water for persistence (40, 60d, respectively). As a result, it is concluded that representative constituents within the substance are easily degraded in the environment and are not be considered to be persistent.

Reference 2

Endpoint:

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

Type of information:

(Q)SAR

Adequacy of study:

key 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:

Standard simulation studies are not designed for petroleum UVCB substances. In accordance with Annex XI Section 1.3 the endpoint has been fulfilled using QSAR calculations for relevant constituents, and testing is not scientifically necessary.

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
- petroleum substances 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: EPISuite v4.10
- Model(s) used: BioHCWin v1.01a
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Attached justification'

Compartment:

water

DT50:

>= 1.46 - <= 6.75 d

Temp.:

20 °C

Remarks on result:

other:

Remarks:

This endpoint is characterised using quantitative structure property relationships for representative hydrocarbon structures that comprise the hydrocarbon blocks used to assess the environmental risk of this substance with the PETRORISK model (see Product Library in PETRORISK spreadsheet attached in IUCLID section 13). For purposes of PBT assessment, the substance has been assessed using a combination of QSAR predictions and confirmatory experimental testing for representative constituents using a hydrocarbon block approach. For details see report titled 'Evaluation of PBT for Petroleum Substances' in IUCLID section 13.

Transformation products:

not measured

Remarks:

potential metabolites of aerobic biodegradation and their relative concentrations are estimated using the Kinetic 301F model in the OASIS/LMC Catalogic software (v5.11.19).

Details on transformation products:

Detailed information including representative structures, phys-chem properties, estimated quantities, 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 Assessment.xlsx" and are atached in the "Full Study report" section below "

Details and justification for the approach is described in the attached file "Framework for Assessing Metabolites for Hydrocarbon Solvent UVCBs" in "Attached Background Material" below.

Validity criteria fulfilled:

yes

Conclusions:

Given the predicted primary half-lives in water, soil, and sediment compartments for the parent constituents and the associated PBT assessment for the predicted metabolites identified, it is concluded that the substance is 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 or its metabolites.

Executive summary:

The registered substance is a complex UVCB whose constituents have variable physicochemical properties. Therefore, a modeling framework is needed. The BIOHCWIN primary degradation model for petroleum hydrocarbons has been applied. As such, modeled data are considered fit for purpose.

 

Given the predicted primary half-lives in water, soil, and sediment compartments for the parent constituents and the associated PBT assessment for the predicted metabolites identified, it is concluded that the substance is 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 or its metabolites.

Reference 3

Endpoint:

biodegradation in water: sediment simulation testing

Type of information:

(Q)SAR

Adequacy of study:

key 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:

Standard simulation studies are not designed for petroleum UVCB substances. In accordance with Annex XI Section 1.3 the endpoint has been fulfilled using QSAR calculations for relevant constituents, and testing is not scientifically necessary.

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
- petroleum substances 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: EPISuite v4.10
- Model(s) used: BioHCWin v1.01a
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Attached justification'

Compartment:

sediment

DT50:

>= 5.9 - <= 27 d

Temp.:

20 °C

Remarks on result:

other:

Remarks:

This endpoint is characterised using quantitative structure property relationships for representative hydrocarbon structures that comprise the hydrocarbon blocks used to assess the environmental risk of this substance with the PETRORISK model (see Product Library in PETRORISK spreadsheet attached in IUCLID section 13). For purposes of PBT assessment, the substance has been assessed using a combination of QSAR predictions and confirmatory experimental testing for representative constituents using a hyd rocarbon block approach. For details see report titled 'Evaluation of PBT for Petroleum Substances' in IUCLID section 13.

Transformation products:

not specified

Remarks:

potential metabolites of aerobic biodegradation and their relative concentrations are estimated using the Kinetic 301F model in the OASIS/LMC Catalogic software (v5.11.19).

Details on transformation products:

Detailed information including representative structures, phys-chem properties, estimated quantities, 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 Assessment.xlsx" and are atached in the "Full Study report" section below "

Details and justification for the approach is described in the attached file "Framework for Assessing Metabolites for Hydrocarbon Solvent UVCBs" in "Attached Background Material" below.

Validity criteria fulfilled:

yes

Conclusions:

Given the predicted primary half-lives in water, soil, and sediment compartments for the parent constituents and the associated PBT assessment for the predicted metabolites identified, it is concluded that the substance is 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 or its metabolites.

Executive summary:

The registered substance is a complex UVCB whose constituents have variable physicochemical properties. Therefore, a modeling framework is needed. The BIOHCWIN primary degradation model for petroleum hydrocarbons has been applied. As such, modeled data are considered fit for purpose.

 

Given the predicted primary half-lives in water, soil, and sediment compartments for the parent constituents and the associated PBT assessment for the predicted metabolites identified, it is concluded that the substance is 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 or its metabolites.

Description of key information

Standard simulation studies are not designed for petroleum UVCB substances.  In accordance with Annex XI Section 1.3 the endpoint has been fulfilled using QSAR calculations for representative hydrocarbon structures that comprise the hydrocarbon blocks used to assess the environmental risk of this substance with the PETRORISK model (see Product Library in PETRORISK spreadsheet attached in IUCLID section 13), and testing is not scientifically necessary.

Additionally, freshwater half-lives are available for 26 constituents and range from 1.4 - 11.8 d, marine water half-lives are available for 5 constituents and range from 0.5 to 3 d. No constituents were identified to exceed the half-life criteria in freshwater or marine water for persistence (40, 60d, respectively). As a result, it is concluded that representative constituents within the substance are easily degraded in the environment and are not considered to be persistent.

For purposes of PBT assessment, the substance has been assessed using a combination of QSAR predictions and confirmatory experimental testing for representative constituents using a hyd rocarbon block approach. For details see report titled 'Evaluation of PBT for Petroleum Substances' in IUCLID section 13.

Additional information

Degradation rates

As part of the exposure assessment, half-lives in air, water, soil, and sediment were calculated using BioHCWin within the PETRORISK model (see Product Library in PETRORISK spreadsheet attached to IUCLID section 13).

Additionally, Freshwater half-lives are available for 26 constituents and range from 1.4 - 11.8 d, marine water half-lives are available for 5 constituents and range from 0.5 to 3 d. 

Table 8. Degradation rates

 

Degradation rate in water:	See Attached PetroRisk File (13.2) and Attached PBT Report (13.2) IUCLID
Degradation rate in sediment:	See IUCLID section 13
Degradation rate in soil:	See IUCLID section 13
Degradation rate in air:	See IUCLID section 13