Fatty acids, linseed-oil, reaction products with bisphenol A-epichlorohydrin polymer and glycidyl neodecanoate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From February 17, 2016 o March 22, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch no.: #210162718
Composition: Reaction products of linseed-oil fatty acids, 4,4'-methylendiphenyldiglycidylether with neodecanoic fatty acid, oxiranylmethylester
Purity: 100 % as per definition of UVCB
Appearance: brown liquid

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Remarks:

concentration in the test: 25.0 mg dry matter/L

Details on inoculum:

Activated sludge from a biologic sewage treatment plant was used. The chosen plant was treating mostly domestic sewage. The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf (batch no: 20160219). The sludge was filtrated, washed with tap water (2x), then washed with and re-suspended
in test medium. It was then aerated until use. The dry matter was determined with 4060 mg suspended solids/L.

Duration of test (contact time):

28 d

Initial conc.:

27.3 mg/L

Based on:

other: nominally 20 mg organic carbon/L

Parameter followed for biodegradation estimation:

CO2 evolution

Remarks:

emitted CO2 were made by IC measurement using the carbon analyser TOC

Details on study design:

- The medium was prepared from the stock solutions. The stock solution of the positive control was prepared and its TOC was measured. The inoculum was taken from its source, washed, aerated and the dry matter was determined. The test vessels were filled with medium and inoculum. Then, all flasks were aerated for 72 hours with purified, CO2-free, moistened air to purge the system of CO2. On the day of the start of the test, CO2-free medium and inoculum was filled into the test flask.
- Experimental parameters:
Flask volume: 1500 mL
Apparatus blanks: 2, containing mineral medium only
Blank Controls: 2, containing mineral medium and inoculum
Positive control flasks: 2, containing positive control, mineral medium and inoculum
Test flasks: 2, containing test substance, mineral medium and inoculum
Abiotic: control 1, containing test substance, mineral medium and HgCl2
Toxicity control: 1, containing test substance, positive control, mineral medium and inoculum
Inoculum concentration: 25.0 mg/L
Temperature: 19.1 – 21.6 °C
Duration: 28 days
The test was performed with a nominal start concentration of 20 mg organic carbon/L.
- The emitted CO2 was trapped in 0.25 M NaOH. Two scrubbers containing 100 mL each were connected in series to the test vessels. The initial IC value of the 0.25 M NaOH was separately determined in each flask.
- Sampling: from each front scrubber flask, 10 samples were taken in order to determine the emitted CO2 (on day 0, 2, 4, 7, 9, 11, 14, 18, 23 and 29). The sample volume was 1 mL. The resulting change in the volume of the front flask was considered in the calculation of emitted CO2 (see also chapter 8.2.1). On day 28, 5 mL HCl 2 M was added to each test flask in order to drive off dissolved CO2. On day 29, samples from both scrubber flasks were taken.
- CO2 Determination: analyses of the emitted CO2 were made by IC measurement using the carbon analyser TOC.

Reference substance:

aniline

Key result

Parameter:

% degradation (CO2 evolution)

Remarks:

made by IC measurement

Value:

53

Sampling time:

28 d

Remarks on result:

other: not readily biodegradable

Details on results:

The following data were determined for the test substance:
- 10-day-window (day 7 – 17): degradation at the end = 33%
- degradation at the end of the test (28 days) = 53%
Pass level following guideline: 60% at the end of the test for mixtures. As degradation didn’t reach the target of 60% within 28 days, the test substance was considered as not readily biodegradable. However, at the end of the test, no plateau of degradation was reached yet, indicating further biodegradation is possible.

NB. Degradation behaviour of positive control and toxicity control was normal. Abiotic degradation reached 1%. Both replicates of the test substance showed very good correspondence. If degradation in the toxicity flask is below 25% after 14 days, the test substance can be considered as toxic towards the inoculum. As degradation in the toxicity flask was 49% after 14 days, the test substance could be stated as “not toxic towards the inoculum in a concentration of 28.0 mg/L”.

Results with reference substance:

Degradation of the positive control (aniline) was 69% after 11 days.

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

Under the study conditions, the test substance was considered as ‘not readily biodegradable’ in the CO2 evolution test. Nevertheless, considering that no plateau of degradation was reached at the end of 28 days indicates that the test substance is inherently biodegradable.

Executive summary:

A study was conducted to determine the biodegradation in water of the test substance, according to OECD Guideline 301 B and EU Method C.4-C (CO2evolution test), in compliance with GLP. The substance was tested in duplicate at the concentration of 20 mg organic carbon/L (corresponding to 27.3 mg test substance/L) for duration of 28 days. Test and reference substances (positive control: aniline and toxicity control; test substance plus aniline) were added to the bottles containing the microbial organisms (domestic sludge) and mineral components followed by sampling on Day 0, 2, 4, 7, 9, 11, 14, 18, 23 and 29 to measure the CO2 evolution. The amount of CO2 produced was determined by inorganic carbon (IC) measurement using the carbon analyser TOC. Each sample was measured in duplicate or triplicate depending upon the variation. The test substance revealed 53% biodegradation (based on IC) in the duplicate test bottles. No toxicity of the test substance was observed in the toxicity control at a concentration of 28 mg/L; there was 49% degradation after 14 days. Abiotic degradation was not observed. Degradation of the positive control was 69% after 11 days. All validity criteria were met. Under the study conditions, the test substance was considered as ‘not readily biodegradable’ in a CO2 evolution test (Muckle, 2016). Nevertheless, considering that no plateau of degradation was reached at the end of 28 days indicates that the test substance is inherently biodegradable.

Description of key information

The test substance showed 53% degradation in 28 days. However, no plateau of degradation was reached at the end of the study, whcih indicates an inherent biodegradation potential.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Additional information

A study was conducted to determine the biodegradation in water of the test substance, according to OECD Guideline 301 B and EU Method C.4-C (CO2evolution test), in compliance with GLP. The substance was tested in duplicate at the concentration of 20 mg organic carbon/L (corresponding to 27.3 mg test substance/L) for duration of 28 days. Test and reference substances (positive control: aniline and toxicity control; test substance plus aniline) were added to the bottles containing the microbial organisms (domestic sludge) and mineral components followed by sampling on Day 0, 2, 4, 7, 9, 11, 14, 18, 23 and 29 to measure the CO2 evolution. The amount of CO2 produced was determined by inorganic carbon (IC) measurement using the carbon analyser TOC. Each sample was measured in duplicate or triplicate depending upon the variation. The test substance revealed 53% biodegradation (based on IC) in the duplicate test bottles. No toxicity of the test substance was observed in the toxicity control at a concentration of 28 mg/L; there was 49% degradation after 14 days. Abiotic degradation was not observed. Degradation of the positive control was 69% after 11 days. All validity criteria were met. Under the study conditions, the test substance was considered as ‘not readily biodegradable’ in a CO2 evolution test (Muckle, 2016). Nevertheless, considering that no plateau of degradation was reached at the end of 28 days indicates that the test substance is inherently biodegradable.