Ethyl 3-hydroxypropanoate

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2021-11-12 ~ 2022-01-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

OECD Guideline for Testing of Chemicals, Test No. 201: Freshwater Alga and Cyanobacteria, Growth Inhibition Test (28 Jul, 2011)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Report date:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

ethyl 3-hydroxypropanoate

Cas Number:

623-72-3

Molecular formula:

C5H10O3

IUPAC Name:

ethyl 3-hydroxypropanoate

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

1. Solubility test
Solubility test was conducted using the test solution of 100.000 mg/L prepared by stirring (150 ± 30 RPM, 22.5 ± 1.5 ˚C for 0.5, 24, and 48 hours) and ultrasonication (20 kHz, 0.5 hours). The test solution was filtered using a 0.2 μm PVDF syringe filters. Then the 100.000 mg/L nominal concentration test solution was analyzed using the HPLC analyzer.

2. Limit and range finding test (stability test)
Stability test was conducted using the test solution of 10.000 and 100.000 mg/L prepared by stirring (150 ± 30 RPM, 22.5 ± 1.5 ˚C, 0.5 hours). The test solutions were collected at 0 and 72 hr and filtered using 0.2 μm PVDF syringe filters. Then the test solutions were analyzed using the HPLC analyzer.

3. Definitive test
Test solutions of the control and 100.000 mg/L were collected at 0 hour and 72 hours, and filtered using 0.2 μm PVDF syringe filters. Then the test solutions were analyzed using the HPLC analyzer.

Test solutions

Vehicle:

no

Details on test solutions:

1. Solubility test
Prior to the limit and range finding test, a solubility test was conducted to identify the solubility of the test substance in the dilution water in compliance with ‘Guidance document on aqueous-phase aquatic toxicity testing of difficult test chemicals (OECD Environmental Health and Safety Publications Series on Testing and Assessment No. 23)’.
The test solution of 100.000 mg/L was prepared by adding 0.1025 g of the test substance (purity 97.55 %) to a 1 L volumetric flask and the volume was filled up to the mark with dilution water. Then the test solution was dissolved using a stirrer (150 ± 30 RPM, 22.5 ± 1.5 ˚C for 0.5, 24, and 48 hours) and ultrasonication (20 kHz, 0.5 hours), and filtered with a 0.2 μm PVDF membrane filter (Lot No. 5402236, Hyundai Micro, Korea) and a vacuum pump (GAST, DOA-P704-AC, IDEX Corporation USA).
In results of the solubility test, the solubility of the test substance prepared after 0.5, 24, and 48 hours stirring were 96.682, 96.451, and 95.580 mg/L, respectively, and the solubility by 0.5 hours ultrasonication was 98.398 mg/L. Based on the solubility test, stirring (150 ± 30 RPM, 22.5 ± 1.5 ˚C, 0.5 hours) was selected as the preparation method.

2. Limit and range finding test (stability test)
A stock solution of 100.000 mg/L was prepared by adding 0.1025 g of the test substance to a 1 L volumetric flask and dilution water was added to the mark to make the total volume. Then the test substance was dissolved using a stirrer (150 ± 30 RPM, 22.5 ± 1.5 ℃, 0.5 h) and filtered with a 0.2 μm PVDF membrane filter (Lot No. 5402236, Hyundai Micro, Korea) before use. Limit and range finding tests were conducted at the nominal concentrations of 0.500, 1.000, 10.000, 50.000, and 100.000 mg/L. Each test solution was prepared by diluting the stock solution on the initiation of exposure date.

3. Definitive test
A stock solution of 100.000 mg/L was prepared by adding 0.1025 g of the test substance to a 1 L volumetric flask and dilution water was added to the mark to make the total volume. Then the test substance was dissolved using a stirrer (150 ± 30 RPM, 22.5 ± 1.5 ℃, 0.5 h) and filtered with a 0.2 μm PVDF membrane filter (Lot No. 5402236, Hyundai Micro, Korea) before use. The definitive test was conducted at the nominal concentrations of 100.000 mg/L as a limit test. Each test solution was prepared by diluting the stock solution on the initiation of exposure date.

Test organisms

Test organisms (species):

other: Pseudokirchneriella subcapitata

Details on test organisms:

# Test species information
- Test species : Pseudokirchneriella subcapitata
- Supplier : Risk Assessment Division, NIER
- Justification of selection : Pseudokirchneriella subcapitata is a suitable plant model for toxicity studies and has been widely used. Abundant data exist for this species and are available for use in interpretation and evaluation for this type of study.
- Selection of the test species : After being examined for morphological alteration (swelling, flocculation, atrophy, decoloration, and rupture), freshwater algae that reached the exponential
growth stage were used for the test.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

Morphological abnormality (swelling, flocculation, atrophy, decoloration, and rupture) of algal cells in each control and test group was checked by microscope and hemocytometer at the end of the test (72 hours).

Test conditions

Test temperature:

22.2-22.3 ˚C

pH:

Before exposure (0 hour), and the pH of the control : 8.27 and 7.79
At the end of the test (72 hours), the pH was 7.89 and 7.86

Nominal and measured concentrations:

The test solutions of the control and the 100.000 mg/L test group were collected and analyzed at 0 and 72 hours.
The measured concentrations in the nominal concentration (100.000 mg/L) were 100.934 mg/L at 0 hour and 97.066 mg/L at 72 hours. The concentration change of test substance in the nominal concentration (100.000 mg/L) after 72 hours was -3.8 %.

Results and discussion

Effect concentrations

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 98.981 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

not determinable

Details on results:

In results of the acute toxicity test of Ethyl 3-hydroxypropanoate in freshwater algae (Pseudokirchneriella subcapitata), the 72-hour EC50 of yield and average specific growth rate based on the nominal concentration was > 100.000 mg/L, and based on the measured concentration was > 98.981 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In results of the acute toxicity test of Ethyl 3-hydroxypropanoate in freshwater algae (Pseudokirchneriella subcapitata), the 72-hour EC50 of yield and average specific growth rate based on the nominal concentration was > 100.000 mg/L, and based on the measured concentration was > 98.981 mg/L.