Prop-2-yn-1-yl 1H-imidazole-1-carboxylate

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:

30 Sep. 2021-27 Jan. 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Report date:

2022

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

adopted 13. Apr. 2004

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

adopted 30. May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

prop-2-yn-1-yl 1H-imidazole-1-carboxylate

EC Number:

695-595-2

Cas Number:

83395-38-4

Molecular formula:

C7H6N2O2

IUPAC Name:

prop-2-yn-1-yl 1H-imidazole-1-carboxylate

Test material form:

solid

Specific details on test material used for the study:

Name: 2-propyn-1-yl 1H-imidazole-1-carboxylate
Batch no.: 0802-2#
CAS no.: 83395-38-4
Storage: fridge (2 - 8 °C) under inert gas
Expiry date: 21. Mar. 2022
Appearance: white solid
Purity: 99.1 %
Homogeneity: homogeneous
Production date: 13. Oct. 2020
EC no.: 695-595-2
Molecular formula: C7H6N2O2
Molecular weight: 150.13 g/mol

Sampling and analysis

Analytical monitoring:

not specified

Details on sampling:

- Concentrations: 4.6/ 10 / 22 / 46 / 100 mg/L nominal concentration
- Sampling method: 21.5 hours before the start of the test, the adult animals were separated from the young. 55 minutes before test start, the adults were caught with the help of a glass tube, and the newborn daphnia (age < 24h) were sieved from the medium and immediately placed into a beaker containing M4-medium. After the settling-in period, animals which showed no apparent damage were used for the test.
- Sample storage conditions before analysis: stored in the test facility in a closed vessel at room temperature (20 ± 5 °C).

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Blank Control: 4 vessels, each containing 20 ± 5 mL M4-medium and 5 daphnia
- Treatments: 4 vessels, each containing 20 ± 5 mL test solution and 5 daphnia
- Stock solutions containing 101.6 mg/L and 100.6 mg/L in M4-Medium was prepared. The solutions were used as highest treatment and for preparation of the lower concentrated treatments.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Authority: STRAUS
- Strain: Berlin
- Sex: female
- Age: between 0 and 24 hours
- Origin: Umweltbundesamt Berlin
- In-house breeding since: 27. September 2007
- Animal Husbandry: Daphnia magna is bred in the LAUS GmbH throughout the year. The animals are kept for the use in toxicity tests. They multiply by parthenogenesis, thus being genetically identi-cal. The keeping is performed similar to the method described in the OECD guideline, fol-lowing SOP 115 002 01 („Zucht und Hälterung von Daphnia magna STRAUS“), version 14 from 26. Jul. 2021.
Vessels: preserving glasses, nominal volume 2 L
Medium: M4-Medium (recipe of ELENDT)
Food: green algae (Desmodesmus subspicatus)
Medium renewal: twice a week
Photo period: 16/8 hours, using LED’s
Temperature: 20 ± 2 °C

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Test temperature:

19.8 – 20.7 °C

pH:

7.6-7.8

Dissolved oxygen:

8.2-9.2 mg/L

Nominal and measured concentrations:

Nominal concentration: 4.6/ 10 / 22 / 46 / 100 mg/L
Measured concentration: 6.5 / 13.92 / 31.03 / 65.58 and 143.11 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Beakers, glass, nominal volume 50 mL, tall shape
- Medium renewal: after 24 ± 1 hours (semi-static)
- No. of organisms per vessel: 5
- Replicates (Treatments): 4 vessels, each containing 20 ± 5 mL test solution and 5 daphnia
- Replicates (Blank control): 4 vessels, each containing 20 ± 5 mL M4-medium and 5 daphnia

TEST MEDIUM / WATER PARAMETERS
- Test medium: M4 Medium
Deionized water with an enrichment of certain minerals was used in the test. The miner-als which are added comply to the composition M4 derived by ELENDT as stated in the OECD-Guideline.

OTHER TEST CONDITIONS
- Photoperiod: 16/8 hours, using LED’s
- Observation times: 24 and 48 hours

Reference substance (positive control):

yes

Remarks:

Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9)

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 28.29 mg/L

95% CI:

23.23 - 34.42

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the study, the 48 hour EC50 of the test material was determined to be 28.29 mg/L.

Executive summary:

In this guideline (OECD 202) study conducted with GLP certification, the objective of this study was to evaluate the toxicity of the test item 2-propyn-1-yl 1H-imidazole-1-carboxylate in an acute immobilisa-tion test under semi-static conditions towards Daphnia magna.
The study was performed using 5 concentrations ranging from 4.6 to 100 mg/L nominal concentration. For each test concentration and the blank control, 20 daphnia were ex-posed to the test item for 48 hours. Because the test item is not stable under test condi-tions, the study was performed under semi-static test conditions. After 24 hours the daph-nia were put in fresh prepared test solutions. After 24 and 48 hours, the immobilised daphnia were counted.
The concentrations showed toxicity between 5 % and 100 % immobilisation. None of the animals was immobilised in the blank control.
At the start and at the end of the test and after 24 h in the new and old solutions, the con-tent of the test item in the test solutions was determined using HPLC-UV-determination. The measured concentrations in the fresh prepared solutions were in a range of 126 % – 143 % of the nominal concentrations and in the old solutions in a range of 24 % - 44 % of the nominal concentrations. In the lowest tested concentration 4.6 mg/l at the end of the test no test item was detectable.
Because the measured test item concentration was not in the range of ± 20 % of the nom-inal concentrations, the determination of the results was based on the time-weighted arithmetic mean of the measured concentrations.
Because significant toxicity was observed only in the two highest concentrations, only the three highest concentrations were used for determination of the EC50 values via regres-sion analysis.
Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a current reference study to assure that the test conditions are reliable. The 24h-EC50 value lay within the range of the laboratory (1.20 – 2.82 mg/L).
The following result was determined for the test item 2-propyn-1-yl 1H-imidazole-1-carboxylate (species: Daphnia magna): 48h-EC50 = 28.29 mg/L