Hydroxyoctadecanoic acid, monoester with glycerol

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

09 February to 12 February 2018

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

2006 (Annex 5 Correction July 28, 2011)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

A sample of the test substance, Glyceryl Monohydroxystearate (Synonyms: GMHS, Naturechem GMHS), an off-white solid was received from EAG Laboratories (formerly Wildlife International), Easton, Maryland on 29 November 2017 and was stored at room temperature.

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

The parent stock of Pseudokirchneriella subcapitata, formerly known as Selenastrum capricornutum, was obtained from the Department of Botany, Culture Collection of Algae, University of Texas at Austin, on 18 July 2017. The prepared cultures were maintained in a temperature-controlled environmental chamber under continuous light.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23.5°C to 25.0°C

pH:

7.3 to 7.5

Nominal and measured concentrations:

The substance was tested at five nominal concentration levels of 6.3 mg/L, 13 mg/L, 25 mg/L, 50mg/L, and 100 mg/L.

Details on test conditions:

Following preliminary range-finding tests, a definitive test was conducted exposing the unicellular green alga, Pseudokirchneriella subcapitata to aqueous WAF solutions of the test item at nominal concentrations of 6.3 mg/L, 13 mg/L, 25 mg/L, 50 mg/L and 100 mg/L for 72 hours at a temperature of 23.5 to 25.0°C. The primary objective of the test was to define the concentration response curve and estimate 72 hour EC50 values for GMHS. The EC50 estimates were based on growth rate (i.e., ErC50) and yield (i.e., EyC50).

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Validity criteria fulfilled:

yes

Remarks:

Algal cells in control at 72 h > 16 times original; mean coef. of var. daily growth rates in control reps not > 35%; coeff.of var. of avg sp.growth rates in control reps did not exceed 7%.; pH in the control did not increase more than 1.5.

Conclusions:

The test substance did not cause a reduction of growth in a series of algal cultures (test units) exposed to the test item for 72 h. The 72 h NOEC and the 72 h EC50 was 100 mg/L or greater as determined by comparison of areas in growth curves. The 24 h to 48 h NOEC EC50 was 100 mg/L or greater as determined by comparison of growth rates.

Description of key information

The key study was a static acute toxicity test on the effects of the substance on the freshwater unicellular green alga, Pseudokirchneriella subcapitata following OECD Guideline 201. The test substance did not cause a reduction of growth in a series of algal cultures (test units) exposed to the test item for 72 h. The 72 h NOEC and the 72 h EC50 were 100 mg/L or greater as determined by comparison of areas in growth curves. The 24-h to 48 h NOEC EC50 was 100 mg/L or greater as determined by comparison of growth rates.

 

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L