12-hydroxy-N-(2-hydroxyethyl)octadecan-1-amide

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:

January 02, 2018 - April 12, 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Data is from experimental study report

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Duplicate samples from the freshly prepared test media (containing algae) of all test concentrations and from the control were taken at the start of the test.
For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentrations during the test period, duplicate samples from the test media of all test concentrations and the control (containing algae) were taken at the end of the test (after the 72 hours test period) by pouring together the contents of the test beakers of each treatment. In addition, samples were taken after 24 and 48 hours test duration from the additional vessel for analytical sampling.The samples were diluted by a factor of two with acetonitrile.One additional sample of the control and of the dilution solvent was taken at test start and test end without any sample treatment.

Vehicle:

no

Details on test solutions:

An aqueous solution of 12-Hydroxy-N-(2-hydroxyethyl)octadecan-1-amide in test media with a concentration (nominal: 100.1 mg/L) as close to saturation as possible was obtained first . This stock solution and dilutions of this “stock solution” by 1:3, 1:9, 1:27 and 1:81 were prepared for testing. Additionally, a control was tested in parallel.The stock solutions and dilutions correspond to the following nominal concentrations of the test item: 100.1, 33.4, 11.1, 3.70 and 1.24 mg test item/L, and a control.Before test start, a ´stock solution´ (100.1 mg/L) of 12-Hydroxy-N-(2-hydroxyethyl)octadecan-1-amide in test medium was prepared as close to the water solubility limit as possible by dissolving 106.21 mg test item in 1061.0 mL test water. The test medium was stirred with an excess of 12-Hydroxy-N-(2-hydroxyethyl)octadecan-1-amide in a vessel for 24 hours at 150 rpm. Afterwards the test medium was allowed to settle for 1 hour. This ´stock solution´was withdrawn from a tap at the center of the vessel, after first flushing the tap and tubing with a small aliquot, and then mixed with test medium to produce the desired set of test concentrations (see ´Test Concentrations´ above). The test media were prepared just before introduction of the algae (=start of the test).

Test organisms (species):

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

Details on test organisms:

The algae were supplied by the „Sammlung von Algenkulturen, Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Universität Göttingen", 37073 Göttingen, Germany.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

Calculated water hardness of the test water: 0.24 mmol/L (= 24 mg/L) as CaCO3.

Test temperature:

22.3 to 22.9 °C

pH:

7.8 to 8.0 at test start
9.3 to 9.6 at test end

Nominal and measured concentrations:

Summary of Analytical Results

Sample description Geometric mean measured1,2
Nominal % of concentration3
concentration nominal3 [µg test item/L]

Control n.a. n.a.
1:81 dilution 0.0153 0.189
1:27 dilution 0.00648 0.240
1:9 dilution 0.00849 0.945
1:3 dilution 0.00863 2.88
'stock solution' 100.1 mg/L 0.00553 5.54

1 Mean value of all measured samples per treatment group
2 Calculated according to OECD Guidance Document No. 23, Annex 2
3 The tabulated results represent results rounded to three significant digits
n.a.: not applicable

Details on test conditions:

The test was started (0 hours) by inoculation of a biomass of approx. 5000 algal cells per mL test medium. These cells were taken from an exponentially growing pre-culture, which was set up 4 days prior to the test start under the same conditions as in the test.The test was performed with three replicates per test concentration and six replicates in the control. Volumes of approximately 50 mL of algal suspension per replicate were continuously stirred with magnetic stirrers in 50 mL Erlenmeyer flasks. The flasks were covered with glass dishes and incubated in a water bath. The flasks were placed in a random order and were repositioned each day to minimize differences in test conditions.
The cell density on each observation time was determined by spectrophotometric measurement. Therefore, defined volumes of the algal suspensions from all replicates and from the blanks were sampled after 24, 48 and 72 hours of exposure.

Reference substance (positive control):

yes

Remarks:

For the evaluation of the quality of the algae and the experimental conditions the reference item potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions.

Key result

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

> 100.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOELR

Effect conc.:

> 100.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EL10

Effect conc.:

> 100.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EL20

Effect conc.:

> 100.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

> 100.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

LOELR

Effect conc.:

> 100.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

EL10

Effect conc.:

> 100.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

EL20

Effect conc.:

> 100.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Validity criteria fulfilled:

yes

Conclusions:

The influence of 12-Hydroxy-N-(2-hydroxyethyl)octadecan-1-amide on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a static concentration-response test. The 72-hour EyC50 (EyL50) was determined to be > 100.1 mg test item/L, and the 72-hour ErC50 (ErL50) value was determined to be > 100.1 mg test item/L. The 72-hour NOEyC (NOEyLR) was determined to be ≥ 100.1 mg test item/L and the associated 72-hour LOEyC (LOEyLR) was > 100.1 mg test item/L. The 72-hour NOErC (NOErLR) was determined to be ≥ 100.1 mg test item/L and the associated 72-hour LOErC (NOErLR) was > 100.1 mg test item/L.The initial concentrations and the maintenance of the exposure concentrations during the test were determined in the analytical part. All reported results refer to nominal values since the maximal soluble test item concentration was applied to the test but no effects occured.

Executive summary:

The influence of 12-Hydroxy-N-(2-hydroxyethyl)octadecan-1-amide on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a static concentration-response test.The 72-hour EyC50 (EyL50) was determined to be > 100.1 mg test item/L, and the 72-hour ErC50 (ErL50) value was determined to be > 100.1 mg test item/L. The 72-hour NOEyC (NOEyLR) was determined to be ≥ 100.1 mg test item/L and the associated 72-hour LOEyC (LOEyLR) was > 100.1 mg test item/L. The 72-hour NOErC (NOErLR) was determined to be ≥ 100.1 mg test item/L and the associated 72-hour LOErC (NOErLR) was > 100.1 mg test item/L.The initial concentrations and the maintenance of the exposure concentrations during the test were determined in the analytical part. All reported results refer to nominal values since the maximal soluble test item concentration was applied to the test but no effects occured.

Description of key information

Toxicity to aquatic algae and cyanobacteria:

The influence of 12-Hydroxy-N-(2-hydroxyethyl)octadecan-1-amide on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a static concentration-response test.The 72-hour EyC50 (EyL50) was determined to be > 100.1 mg test item/L, and the 72-hour ErC50 (ErL50) value was determined to be > 100.1 mg test item/L. The 72-hour NOEyC (NOEyLR) was determined to be ≥ 100.1 mg test item/L and the associated 72-hour LOEyC (LOEyLR) was > 100.1 mg test item/L. The 72-hour NOErC (NOErLR) was determined to be ≥ 100.1 mg test item/L and the associated 72-hour LOErC (NOErLR) was > 100.1 mg test item/L.The initial concentrations and the maintenance of the exposure concentrations during the test were determined in the analytical part. All reported results refer to nominal values since the maximal soluble test item concentration was applied to the test but no effects occured.

Thus, thet test chemical has no adverse effect on aquatic environment and cannot be classified as per CLP Criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:

100.1 mg/L

Additional information

Toxicity to aquatic algae and cyanobacteria:

The influence of 12-Hydroxy-N-(2-hydroxyethyl)octadecan-1-amide on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a static concentration-response test.The 72-hour EyC50 (EyL50) was determined to be > 100.1 mg test item/L, and the 72-hour ErC50 (ErL50) value was determined to be > 100.1 mg test item/L. The 72-hour NOEyC (NOEyLR) was determined to be ≥ 100.1 mg test item/L and the associated 72-hour LOEyC (LOEyLR) was > 100.1 mg test item/L. The 72-hour NOErC (NOErLR) was determined to be ≥ 100.1 mg test item/L and the associated 72-hour LOErC (NOErLR) was > 100.1 mg test item/L.The initial concentrations and the maintenance of the exposure concentrations during the test were determined in the analytical part. All reported results refer to nominal values since the maximal soluble test item concentration was applied to the test but no effects occured.

Thus, thet test chemical has no adverse effect on aquatic environment and cannot be classified as per CLP Criteria.