Naphtha (petroleum), light steam-cracked arom.

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil: 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:

This endpoint is adapted in accordance with REACH Annex XI, Section 1.3 (QSAR). The constituents in the category have a low potential for adsorption to soil. This indicates that the surface water biodegradation rates measured or predicted using QSARs would be applicable to soil. An evaluation extrapolation factor of 1 was implemented to the water half-lives to calculate sediment half-lives for screening purposes, acording to Boethling et. al (1995). Measured freshwater biodegradation rates were obtained from the Concawe Report (2019), which provides water experimental primary biodegradation half-lives for petroleum substances from reliable sources, including peer-reviewed studies. BioHCWin model biodegradation rates were used for constituents for which no experimental data was available. The BioHCwin model is a well documented and commonly used QSARs for predicting the biodegradation potential of chemicals. Constituents within LOA streams with no heteroatoms (those atoms other than carbon or hydrogen) fall within the applicability domain of these models and they have been recommended by ECHA in the Information Requirement Guidelines.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

assessment report

Cross-reference 2

Reason / purpose for cross-reference:

(Q)SAR model reporting (QMRF)

Data source

Reference

Reference 1

Reference Type:

publication

Title:

A New Biodegradation Prediction Model Specific to Petroleum Hydrocarbons.

Author:

Howard, P.H., Meylan, W.M., Aronson, D., Stiteler,W.M., Tunkel, J., Comber, M. and Parkerton, F.

Year:

2005

Bibliographic source:

Environ. Toxicol. Chem. 24(8): 1847-1860.

Reference 2

Reference Type:

other: Computer QSAR model

Title:

Episuite v4.11

Author:

US EPA

Year:

2021

Bibliographic source:

EPA

Report date:

2021

Reference 3

Reference Type:

publication

Title:

Factors for intermedia extrapolation in biodegradability assessment

Author:

Boethling, R.S., Howard, P.H., Beauman, J.A., Larosch, M.E.

Year:

1995

Bibliographic source:

Chemosphere, 30 (4); 741-752.

Reference 4

Reference Type:

publication

Title:

An Evaluation of the Persistence, Bioaccumulation and Toxicity of Petroleum Hydrocarbons

Author:

Concawe

Year:

2019

Bibliographic source:

Concawe

Report date:

2019

Reference 5

Reference Type:

publication

Title:

Simulation of chemical metabolism for fate and hazard assessment. I. Approach for simulating metabolism

Author:

Dimitrov, S., Pavlov, T., Veith, G., Mekenyan, O.

Year:

2011

Bibliographic source:

SAR QSAR Environ Res; 22 (7-8): 699-718.

Reference 6

Reference Type:

publication

Title:

Simulation of chemical metabolism for fate and hazard assessment. II CATALOGIC simulation of abiotic and microbial degradation

Author:

Dimitrov, S., Pavlov, T., Dimitrova, N., Georgieva, D., Nedelcheva, D., Kesova, A., Vasilev, R., Mekenyan, O.

Year:

2011

Bibliographic source:

SAR QSAR Environ Res; 22 (7-8): 719-55

Materials and methods

Principles of method if other than guideline:

An evaluation extrapolation factor of 1 was implemented to the water half-lives to calculate soil half-lives for screening purposes, according to Boethling et. al (1995). Measured freshwater biodegradation rates were obtained from the Concawe Report (2019), which provides water experimental primary biodegradation half-lives for petroleum substances from reliable sources, including peer-reviewed studies. BioHCWin model v1.01 (EPISuite 4.1, 2017) freshwater biodegradation rates were used for constituents for which no experimental freshwater half-life was available. The BioHCwin program was developed specifically for the biodegradation half-life prediction of petroleum hydrocarbons. Primary biodegradation half-lives for individual petroleum hydrocarbons are estimated using multiple linear regression against distinct molecular fragments, using a similar approach to several other biodegradation models such as those within the Biodegradation Probability Program (BIOWIN). Details on the principles of the method are found in the BioHCwin QMRF/QPRF (see cross-references).

Kinetic 301F model in the OASIS/LMC Catalogic software (v5.11.19) (Dimitrov et al., 2011a, 2011b) simulates aerobic biodegradation under OECD 301F test conditions and was run for all constituents in the category to determine the identity and persistence properties of the degradation products. Since the soil is considered an aerobic system, similar methabolic pathways are considered to occur in water and soil. An evaluation extrapolation factor of 1 was implemented to the metabolite primary water half-lives to calculate metabolite soil primary half-lives for screening purposes, acording to Boethling et. al (1995). Details on the principles of the method are found in the CATALOGIC Kinetic 301F QMRF (see cross-references).

Test material

Test material information

Constituent 1

Reference substance name:

Resin Oils and cyclic dienes category

IUPAC Name:

Resin Oils and cyclic dienes category

Details on test material:

See "Attached background material" in the "Overall remarks, attachments" section below for the detailed composition used in the modelling for this substance

Results and discussion

Half-life / dissipation time of parent compound

Half-life / dissipation time of parent compound 1

Key result

DT50:

>= 0.03 - <= 44.1 d

Remarks on result:

other: Result from 1:1 extrapolation from measured freshwater half-lives. Range based on the measured constituents in the streams (Concawe 2019 report)

Half-life / dissipation time of parent compound 2

Key result

DT50:

>= 1.46 - <= 63.13 d

Remarks on result:

other: Result from 1:1 extrapolation from QSAR predicted freshwater half-lives. Range based on the measured constituents in the streams.

Transformation products:

not measured

Remarks:

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

Details on transformation products:

Potential metabolites of aerobic biodegradation and their relative concentrations have been predicted using the Kinetic 301F model in the OASIS/LMC Catalogic software (v5.11.19). The primary half-lives indicate that most of the unique metabolites have a range of half-lives from less than one day to 28 days and 2 and 31 metabolites had half-lives ranging from 1 month to 9 months and 15 days. The remaining 28 metabolites had half-lives of over one year (>365 days). One metabolite had a half-life of 1-month and 27 (57 days) and a log Kow of 4.54. However, none of the metabolites with half-lives of over one year had log Kow of greater than or equal to 4.5 and are therefore not considered to be bioaccumulative.(see attached Metabolite Persistence Evaluation Report)

Details on results:

Details of the constituent half-lives and how these value relate to their persistence assessment are found in the Persistence Weight of Evidence Evaluation (see cross-reference).

Applicant's summary and conclusion

Conclusions:

The soil half-lives of measured parent constituents of this category range from 1.46 to 63.13 days. None of the 240 parent constituents, have a half-life of greater equal or greater than 120 days. Finally, most of the parent constituents have a log Koc of < 3 which indicates that they will not adsorb to soil particles and are therefore not considered to be persistent in soils. The primary half-lives indicate that 2315 of the 2374 unique metabolites have a range of half-lives from less than one day to 28 days and 31 metabolites had half-lives ranging from 1 month to 9 months and 15 days. The remaining 28 metabolites had half-lives of over one year. One metabolite had a half-life of 1-month and 27 and a log Kow of 4.54. However, none of the metabolites with half-lives of over one year had log Kow of greater than or equal to 4.5 and are therefore not considered to be bioaccumulative.

Executive summary:

The soil half-lives of measured constituents (at equal or above 0.1% w/w) of this category have been extrapolated from measured (Concawe report, 2019) and predicted (EPISUITE v4.11 BioHCwin model, 2017) freshwater half-lives using an extrapolation factor of 1:1 (Boethling et al., 1995). The soil half-lives of measured parent constituents of this category range from 1.46 to 63.13 days. None of the 240 parent constituents, have a half-life of greater than 120 days. Finally, most of the parent constituents have a log Koc of < 3 which indicates that they will not adsorb to soil particles and are therefore not considered to be persistent in soil.

 

Potential metabolites of aerobic biodegradation and their relative concentrations have been predicted using the Kinetic 301F model in the OASIS/LMC Catalogic software (v5.11.19). The primary half-lives indicate that most of the unique metabolites have a range of half-lives from less than one day to 28 days and 31 metabolites had half-lives ranging from 1 month to 9 months and 15 days. The remaining 28 metabolites had half-lives of over one year (>365 days). One metabolite had a half-life of 1-month and 27 (57 days) and a log Kow of 4.54. However, none of the metabolites with half-lives of over one year had log Kow of greater than or equal to 4.5 and are therefore not considered to be bioaccumulative.