Ethyl pyruvate

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:

28 February 2018 - 23 June 2018

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:

Ethyl pyruvate

EC Number:

210-511-2

EC Name:

Ethyl pyruvate

Cas Number:

617-35-6

Molecular formula:

C5H8O3

IUPAC Name:

ethyl 2-oxopropanoate

Test material form:

liquid

Details on test material:

Identification: EC#210-511-2
CAS No.: 89800-10-2
Chemical name: ethyl pyruvate
Appearance/physical state: very pale yellow liquid
Batch: 61112
Purity: 98.54%
Expiry date: 30 September 2018
Storage conditions: room temperature, in the dark

Specific details on test material used for the study:

Identification: EC#210-511-2
CAS Number: 9800-10-2
Batch: 61112
Purity: 98.54%
Physical state/Appearance: Very pale yellow liquid
Expiry Date: 30 September 2018
Storage Conditions: Room temperature in the dark

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations:
- Sample storage conditions before analysis: stored frozen prior to analysis

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A nominal amount of test item (200 mg) was dissolved in test water with the aid of ultrasonication for 5 minutes and the volume adjusted to 2 liters to give the 100 mg/L test concentration from which a series of dilutions was made to give further test concentrations of 10, 18, 32 and 56 mg/L.
- Positive control:potassium dichromate

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Justification for species other than prescribed by test guideline:
- Source: Envigo In house laboratory
- Age of parental stock: less than 24 hours old
- Food type: algal suspension (Desmodesmus subspicatus) and GEMMA Micro 300 suspension (Tetramin® )
- Feeding during test: no
- Feeding frequency: daily
- Lighting cycle: 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods.
- Temperature: 18 to 22 °C.

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Test temperature:

20°C to 22°C

pH:

6.7 - 8.1

Dissolved oxygen:

8.2 - 8.9

Nominal and measured concentrations:

Range finding Test: 0.10, 1.0, 10 and 100 mg/L.
Definitive Test (Nominal Test Concentration): 10, 18, 32, 56 and 100 mg/L.
Definitive Test (Geometric Mean Measured): 0.59, 0.84, 1.2, 4.8 and 25 mg/L.

Details on test conditions:

TEST SYSTEM
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 150 mL glass beakers containing approximately 100 mL of test preparation
- Type of flow-through: semi-staltic
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4


OTHER TEST CONDITIONS
- Photoperiod: 16 hours light and 8 hours darkness cycle with 20-minute dawn and dusk transition periods
- Light intensity: 844 - 875 Lux

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: 0.10, 1.0, 10 and 100 mg/L.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

ca. 25 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

ca. 4.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Effect concentrations 3

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

ca. 25 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Details on results:

As expected for an ester, it was noted that the parent test item (ethyl pyruvate) hydrolyzed readily when added to test media, reverting to the parent carboxylic acid and alcohol in
solution. Given this, samples were provided for immediate chemical analysis at 0, 24 and 48 hours in bottles spiked with 1% v/v formic acid to effectively halt the hydrolysis reaction
and attain the reaction equilibrium.

Analysis of the freshly prepared test preparations at 0 and 24 hours (see Annex 5) showed measured test concentrations to range from 3.3 to 63 mg/L (32% to 63% of the nominal
concentrations). It was considered that failure to attain near nominal concentrations was due to hydrolysis of the parent test item occurring during the time taken to prepare all serial dilutions. Analysis of the old or expired test preparations at 24 and 48 hour showed measured test concentrations had declined, to range from less than the LOQ determined to be 0.21 mg/L to 14 mg/L. Given this decline in measured test concentrations it was considered justifiable to base the results on the geometric mean measured test concentrations in order to give a "worst case" analysis of the data.

The No Observed Effect Concentration after 24 and 48 hours exposure was 4.8 mg/L. The Lowest Observed Effect Concentration after 24 and 48 hours exposure was 25 mg/L. Due to the nature of the data it was not possible to calculate the slope and error of response curve at 24 or 48 hours.

Sub-lethal effects of exposure were observed in test concentrations of 4.8 and 25 mg/L. These responses were reduced mobility and covered in debris.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Exposure of freshwater invertebrate Daphnia magna to the test item has been investigated and gave the following results based on the geometric mean measured test concentrations at time point 48 h:
EC50 - 25 mg/L
NOEC - 4.8 mg/L
LOEC - 25 mg/L

Executive summary:

Introduction

A 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.

Methods

Following a preliminary range-finding test and initial experiment, 20 daphnids (4 replicates of 5 animals) were exposed to an aqueous solution of the test item at nominal concentrations of 10, 18, 32, 56 and 100 mg/L for 48 hours at a temperature of 20 °C to 22 °C under semi-static test conditions. The number of immobilized daphnia were recorded after 24 and 48 hours.

Results

As expected for an ester, it was noted that the parent test item (ethyl pyruvate) hydrolyzed readily when added to test media, reverting to the parent carboxylic acid and alcohol in solution. Given this, samples were provided for immediate chemical analysis at 0, 24 and 48 hours in bottles spiked with 1% v/v formic acid to effectively halt the hydrolysis reaction and attain the reaction equilibrium. Analysis of the freshly prepared test preparations at 0 and 24 hours showed measured test concentrations to range from 3.3 to 63 mg/L (32% to 63% of the nominal concentrations). It was considered that failure to attain near nominal

concentrations was due to hydrolysis of the parent test item occurring during the time taken to prepare all serial dilutions. Analysis of the old or expired test preparations at 24 and 48 hour showed measured test concentrations had declined, to range from less than the limit of quantification (LOQ) determined to be 0.21 mg/L to 14 mg/L. Given this decline in measured test concentrations it was considered justifiable to base the results on the geometric mean measured test concentrations in order to give a "worst case" analysis of the data which were determined to be 0.59, 0.84, 1.2, 4.8 and 25 mg/L.

Exposure of Daphnia magna to the test item gave the following results:

The No Observed Effect Concentration after 24 and 48 hours exposure was 4.8 mg/L. The Lowest Observed Effect Concentration after 24 and 48 hours exposure was 25 mg/L.