N-2-hydroxyethylacetamide

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 July 2017 to 16 December 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N-2-hydroxyethylacetamide

EC Number:

205-530-8

EC Name:

N-2-hydroxyethylacetamide

Cas Number:

142-26-7

Molecular formula:

C4H9NO2

IUPAC Name:

N-2-hydroxyethylacetamide

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Remarks:

LC/MS

Details on sampling:

- Concentrations: nominal 100 mg
- Sampling method: LC/MS
- Sample storage conditions before analysis: The test samples were thawed with the aid of a waterbath, and where necessary diluted into the calibration range with test medium, and then analyzed.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A nominal amount of test item (100 mg) was dissolved in test water and the volume adjusted to 1 liter to give the 100 mg/L test concentration.
The prepared concentration was inverted several times to ensure adequate mixing and homogeneity. The concentration and stability of the test item in the test preparation was verified by chemical analysis at 0 and 48 hours.
- Controls: Negative control
- Evidence of undissolved material: At the start and throughout the test all control and test solutions were observed to be clear colorless solutions.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: first instar Daphnia magnaderived from in-house laboratory cultures
- Age of parental stock (mean and range, SD): Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing.
- Feeding during test: yes
- Food type: Each culture was fed a mixture of algal suspension (Desmodesmus subspicatus) and Tetramin® flake food suspension.
- Amount: not reported
- Frequency: daily

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Test temperature:

21 °C to 22 °C

pH:

The pH of the prepared media was 7.9 ± 0.3.

Dissolved oxygen:

8.7 - 9 mg O2/L

Nominal and measured concentrations:

100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 150 mL glass beakers
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 150 mL glass beakers containing 100 mL Elendt M7 medium
- Aeration: N/A
- Type of flow-through (e.g. peristaltic or proportional diluter): N/A
- Renewal rate of test solution (frequency/flow rate): N/A
- No. of organisms per vessel: 5 daphnids were placed in each test and control vessel
- No. of vessels per control (replicates): Four replicate test and control vessels
- Biomass loading rate: not reported

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water - Elendt M7 medium
- Ingredient and final concentration (mg/L) of medium:
H3BO3= 0.715
MnCl2.4H2O= 0.090
LiCl= 0.077
RbCl= 0.018
SrCl2.6H2O= 0.038
NaBr= 0.004
Na2MoO4.2H2O= 0.016
CuCl2.2H2O= 0.004
ZnCl2= 0.013
CoCl2.6H2O= 0.010
KI= 0.0033
Na2SeO3= 0.0022
NH4VO3= 0.00058
Na2EDTA.2H2O= 0.625
FeSO4.7H2O= 0.249
CaCl2.2H2O= 293.8
NaHCO3= 64.8
MgSO4.7H2O= 123.3
Na2SiO3.9H2O= 10
KCl= 5.8
NaNO3= 0.274
K2HPO4= 0.184
KH2PO4= 0.143
Thiamine hydrochloride= 0.075
Cyanocobalamine (vitaminB=12=) 0.0010
D(+) biotin (vitamin H)= 0.00075

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours light and 8 hours darkness for a period of 48 hours with 20 minute dawn and dusk transition periods.
- Light intensity: 842 to 878 Lux

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: 0.10, 1.0, 10 and 100 mg/L.
- Results used to determine the conditions for the definitive study: No immobilization was observed at the test concentrations of 0.10, 1.0, 10 and 100 mg/L.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate at concentrations of 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L.

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 4

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

No sub-lethal effects of exposure were observed throughout the test.

The test was considered to be valid given that none of the control daphnids showed immobilization or other signs of disease or stress and that the oxygen concentration at the end of the test was equal to or greater than 3 mg/L in the control and test vessels.

Results with reference substance (positive control):

- Results with reference substance valid: yes , The results from the positive control with potassium dichromate were within the normal range for this reference item.
- Relevant effect levels: none
- EC50: 1.3 mg/L at 24 hours and 1.2 mg/L at 48 hours.
- NOEC: 1.0 mg/L at 24 hours and 0.56 mg/L at 48 hours.
- LOEC: 1.8 mg/L at 24 hours and 1.0 mg/L at 48 hours.
- Other: Exposure conditions for the positive control were similar to those in the definitive test, however, throughout the positive control the temperature range was recorded between 19 and 22 °C, therefore outside of the range quoted in the study plan of 18 to 22 °C with a maximum deviation of ±1 °C during the test. This deviation was considered not to have adversely affected the results of the test.

Reported statistics and error estimates:

An estimate of the EC50 values was given by inspection of the immobilization data.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test item to the freshwater invertebrate Daphnia magna has been investigated and gave a 48-Hour EC50 value of greater than 100 mg/L. The No Observed Effect Concentration was 100 mg/L.

Executive summary:

The study was performed to assess the acute toxicity of the test item to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphnia sp., Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008.

 

Following a preliminary range-finding test, twenty daphnids (4 replicates of 5 animals) were exposed to an aqueous solution of the test item at a nominal concentration of 100 mg/L for 48 hours at a temperature of 21 °C to 22 °C under static test conditions. Immobilization and any adverse reactions to exposure were recorded after 24 and 48 hours. Analysis of the test preparations at 0 and 48-hours showed measured test concentrations to be near nominal and so the results are based on nominal test concentrations. Exposure of Daphnia magna to the test item gave EC₅₀ values of greater than 100 mg/L. The No Observed Effect Concentration was 100 mg/L. It was considered unnecessary and unrealistic to test at concentrations in excess of 100 mg/L.

 

The acute toxicity of the test item to the freshwater invertebrate Daphnia magna has been investigated and gave a 48-Hour EC₅₀ value of greater than 100 mg/L. The No Observed Effect Concentration was 100 mg/L.