Hydroxyoctadecanoic acid, monoester with glycerol

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:

21 March 2017 to 19 April 2017

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:

yes

Remarks:

The temperatures in a non-test vessel were recorded at 24.8, 24.9 and 24.8 oC on days 19, 25 and 26 of the test, respectively, outside the specified range of 22 ± 2 oC. This deviation did not affect study integrity since all validation criteria were met.

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

440/2008

Deviations:

yes

Remarks:

The temperatures in a non-test vessel were recorded at 24.8, 24.9 and 24.8 oC on days 19, 25 and 26 of the test, respectively, outside the specified range of 22 ± 2 oC. This deviation did not affect study integrity since all validation criteria were met.

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Version / remarks:

The guideline was identified as OCSPP 835.3110 in the study report.

Deviations:

yes

Remarks:

The temperatures in a non-test vessel were recorded at 24.8, 24.9 and 24.8 oC on days 19, 25 and 26 of the test, respectively, outside the specified range of 22 ± 2 oC. This deviation did not affect study integrity since all validation criteria were met.

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

A mixed population of activated sewage sludge micro-organisms was obtained on 20 March 2017 from the aeration stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK, which treats domestic sewage.

Duration of test (contact time):

28 d

Initial conc.:

14.9 mg/L

Based on:

test mat.

Initial conc.:

10 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

The amount of the test item was dispersed directly in mineral medium with the aid of high shear mixing prior to dispersal in inoculated mineral medium. The volume was adjusted to 3 liters to give a final concentration of 14.9 m/L, equivalent to 10 mg carbon/L.

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Value:

49

Sampling time:

28 d

Validity criteria fulfilled:

yes

Remarks:

IC content 0% & 2% (protocol ≤ 5%); CO2 emitted by controls 32.70 mg/L (protocol <70 mg/L; difference replicates less than 20% (protocol ≤20 %); degradation positive control 87% at 14 d (protocol ≤14 d); degradation toxicity d 14, 40% (protocol > 25%).

Interpretation of results:

not readily biodegradable

Conclusions:

The test substance is considered as “not readily biodegradable”. The test substance reached 49% biodegradation after 28 d.

Description of key information

The key study was a CO₂ evolution test conducted in accordance with OECD Guideline 301B. The substance was not found to be readily biodegradable in a test conducted in accordance with OECD Guideline 301B. The biodegradation was reported as 49% after 28 days. Although this level does not show ready biodegradability, it is indicative of inherent primary degradation and substantial mineralisation.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable