Tall oil, maleated

Biodegradation in soil

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2023

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

laboratory

Specific details on test material used for the study:

Carbon-14 is the isotope of choice in environmental fate studies. The position of labelling is in a chemically and metabolically stable part of the molecule which is suitable for this type of study.

Radiolabelling:

yes

Oxygen conditions:

aerobic

Soil classification:

USDA (US Department of Agriculture)

Year:

2022

Details on soil characteristics:

Suitable soils will be obtained by Charles River from LRA for use in this study. The soils will be supplied in a fresh condition and will be stored under aerobic conditions in a fridge set to maintain 4 °C. Soils will be stored for a maximum of 3 months from the date of collection prior to use. Details on the sampling sites, site history, dates of collection and sampling periods will be supplied with the soils. Suitable soils will be supplied by the Sponsor, Sponsors representative or obtained by Charles River from LRA for use in this study. The soil will be passed through a 2.0 mm sieve upon arrival at Charles River to remove particles larger than coarse sand. Air drying of soil/loss of moisture will be minimised where possible. Soils will be characterised under a separate GLP study and appropriate information included in the final report. These may include, but will not be limited to the following:
• pH (in water and 0.01M CaCl2)
• Organic carbon content
• Water holding capacity at pF 2
• Particle size distribution (UK and USDA classification)
• Cation exchange capacity
The soil moisture content will be determined at Charles River and each soil adjusted to close to pF 2. For each soil, moisture adjustment will be performed on a bulk sample sufficient to allow preparation of all samples from respective incubation groups using a single adjusted batch of soil. The moisture adjustment will be as close to the target weight as possible while maintaining the integrity of the sample. Any soil which cannot be adjusted to target weight will be discussed with the Study Director, who will decide how best to proceed.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on experimental conditions:

See below!

Remarks on result:

not measured/tested

Remarks:

The study could not be initiated as radiolabelled test material was found being not adequate. Thus, new radiolabelled test material is currently produced to start the study with this new batch of radiolabelled material, accordingly.

Transformation products:

not specified

Remarks:

Results are still outstanding

Conclusions:

Currently, the study is still ongoing as it could not be concluded prior to the submission deadline (September 20th, 2022) and the exposure phase on this study will begin presumably in 2023, when new radiolabelled material becomes available. Thereafter, the soil biodegradation examinations will start and a draft report is expected by end of October, 2023. Once available, the robust study summary will be updated and a dossier update will be submitted again.

Reference 2

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2023

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Carbon-14 is the isotope of choice in environmental fate studies. The position of labelling is in a chemically and metabolically stable part of the molecule which is suitable for this type of study.

Radiolabelling:

yes

Oxygen conditions:

aerobic

Remarks on result:

not measured/tested

Remarks:

The study could not be initiated as radiolabelled test material was found being not adequate. Thus, new radiolabelled test material is currently produced to start the study with this new batch of radiolabelled material, accordingly.

Transformation products:

not specified

Remarks:

Results are still outstanding

Conclusions:

Currently, the study is still ongoing as it could not be concluded prior to the submission deadline (September 20th, 2022) and the exposure phase on this study will begin presumably in 2023, when new radiolabelled material becomes available. Thereafter, the soil biodegradation examinations will start and a draft report is expected by end of October, 2023. Once available, the robust study summary will be updated and a dossier update will be submitted again.

Description of key information

To fulfill the testing requirement for soil simulation testing on biodegradation for the UVCB substance, the two main constituents were selected as surrogates for investigation. Maleated tall-oil fatty acid (CAS 6935-55-3) and maleated resin (CAS 4559-23-3) were individually synthesized by reacting linoleic acid and resin, respectively, with 14C-radiolabelled maleic anhydride, where one of the two carbonyl atoms was labelled with 14C. The two radiolabelled model substances were individually investigated in an OECD 307 study protocol.

Unfortunately, the radiolabelled test specimen, when arriving in the test facility, already had degraded significantly and thus, the requirement for >=95% radiolabelling was not fulfilled anymore. Hence, the biodegradation study could not be initiated as planned and radiolabelled material has to be re-synthesized first.

This has lead to significant delays and the two studies are not concluded. Once degradation results and a final report become available, the dossier will be updated.