Hydroxyoctadecanoic acid, monoester with glycerol

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms, other

Remarks:

Study was a toxicity control conducted as part of a CO2 evolution test in accordance with OECD Guideline 301B.

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:

other: According to OECD 310B and EU C.4-C

Version / remarks:

Toxicity test performed as part of a ready biodegradability CO2 evolution test performed according to OECD 301B and EU C.4-C.

Deviations:

yes

Remarks:

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

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

The test substance is listed as Naturechem® GMHS (Glycerol Monohydroxystearate). The test substance is an off white solid. The test substance was obtained from the Sponsor, Vertellus Holdings LLC and stored at room temperature in the dark.

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

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.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

28 d

Nominal and measured concentrations:

A toxicity control, containing the test item and sodium benzoate was prepared to assess any toxic effect of the test item on the sewage sludge micro-organisms used in the test. 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 with the aid of high shear mixing. An aliquot (51.4 mL) of the sodium benzoate stock solution was aldded to the test vessel and the volume adjusted to 3 liters to give a final nominal concentration of 14.9 mg test item//L plus 17.1 mg sodium benzoate/L, equivalent to a total of 20 mg carbon/L.

Key result

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

14.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: : inhibition of CO2 evolution

Remarks on result:

other:

Remarks:

Toxicity test performed as part of a ready biodegradability CO2 evolution test performed according to OECD 301B and EU C.4-C.

Details on results:

At a test substance concentration of 14.9 mg/L and a reference substance concentration of 17.1 mg sodium benzoate/L, the toxicity control attained 40% degradation after 14 days and 55% degradation after 28 days, thereby confirming that the test substance did not exhibit an inhibitory effect on the sewage treatment micro-organisms used in the test (i.e., test substance and reference substance attained ≥ 25% degradation by Day 14 for the test substance to be considered as non-inhibitory).

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%).

Conclusions:

The test substance is considered as not toxic towards the inoculum at a concentration of 14.9 mg/L. Degradation in the toxicity flask was 40% after 14 days. The guideline indicates that the test item can be considered as toxic towards the inoculum if degradation in the toxicity flask is below 25% after 14 days.

Description of key information

The key study was a toxicity control conducted as part of a CO₂ evolution test in accordance with OECD Guideline 301B. The test substance was shown to be non-inhibitory toward the inoculum at a concentration of 14.9 mg/L. Degradation in the toxicity flask was 40% after 14 days.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

14.9 mg/L