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

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 22 JUL 2022 to 25 OCT 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

adopted on 18 June 2019

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Name: prop-2-yn-1-yl 1H-imidazole-1-carboxylate
Chemical Formula: C7H6N2O2
CAS no.: 83395-38-4
Physical Appearance (with color): white solid
Lot No.: S021110385
Purity (Declared by sponsor and / or as per Certificate of Analysis): 99.7789 %
Date of Manufacture: 2021.11.3
Date of Expiry: 2023.5.6
Storage conditions: Cool and dry (2 to 8°C)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Dose range finding study was conducted with 6 concentrations of 0.19, 0.43, 0.94, 2.07, 4.55 and 10.0 mg/L; the main study was conducted at the test concentrations of 0.16, 0.31, 0.63, 1.25, 2.50, 5.00 and 10.00 mg/L.
- Sampling method: The test item stock solution was prepared by weighing required quantity of test item in a beaker, to this small volume of tap water (reverse osmosis water) was added and stirred well, after complete soluble of test item, test volume was transferred to measuring cylinder, beaker was rinsed with tap water (reverse osmosis water) and transferred again to measuring cylinder, the rinsing process was repeated until the complete transfer of test contents. Finally, the volume was made up to required volume using tap water (reverse osmosis water).
The test item stock solution was prepared by weighing required quantity of test item in a beaker, to this small volume of tap water (reverse osmosis water) was added and stirred well, after complete soluble of test item, test volume was transferred to measuring cylinder, beaker was rinsed with tap water (reverse osmosis water) and transferred again to measuring cylinder, the rinsing process was repeated until the complete transfer of test contents. Finally, the volume was made up to required volume using tap water (reverse osmosis water).
- Sample storage conditions before analysis: cool and dry (2 to 8°C)

Vehicle:

no

Details on test solutions:

Seven groups [1 control and 6 treatment groups] consisting of 7 fish in each group were used during the dose range finding study.
Eight groups [1 control and 7 treatment groups] consisting of 7 fish in each group were used during the main study.
A maximum loading of fish was 0.32 and 0.28 g wet weight of fish/L during dose range finding study and main study respectively.
Stock solution 10 mg/mL in test medium was prepared. The lower treatments (0.19, 0.43, 0.94, 2.07, 4.55, 10.0 mg/L for dose range finding study and 0.16, 0.31, 0.63, 1.25, 2.50, 5.00, 10.00 mg/L for the main study) were prepared by diluting of these stock solutions with test medium.

Test organisms (species):

Cyprinus carpio

Details on test organisms:

TEST ORGANISM
- Common name: Cyprinus carpio
- Strain: Common carp
- Source: In-house maintained Cyprinus carpio (common carp) procured from Fisheries Research and Information Center (Inland), Hesaraghatta, Bangalore, Karnataka, India.
- Length: 2.5 to 3.9 cm(in the dose range) ; 2.6 to 3.9 cm(during main study).

ACCLIMATION
- Acclimation period: 9 days
- Acclimation conditions (same as test or not): same as test
- Type and amount of food during acclimation: commercial feed pellets (Kijaro Grow).
- Feeding frequency during acclimation: Fishes were fed ad libitum daily. Feeding was stopped approximately 24 hour prior to commencement of the exposure to test item.
- Health during acclimation (any mortality observed): No mortality was observed.

A day prior to exposure, the fish were randomly and impartially selected for all the groups (grouping) and weighed in groups to determine the biomass (loading rate) during the test.
A maximum loading of fish was 0.32 and 0.28 g wet weight of fish/L during dose range finding study and main study respectively.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

Dose Range Finding Study: 173.2 to 174.9 mg CaCO3/L;
Main Study: 173.2 mg CaCO3/L.

Test temperature:

Dose Range Finding Study: 22.0 to 22.8 ℃;
Main Study: 21.0 to 22.6 ℃.

pH:

Dose Range Finding Study: 7.15 to 7.47;
Main Study: 7.26 to 7.55.

Dissolved oxygen:

Dose Range Finding Study: ˃84.9%;
Main Study: >80.0%.

Nominal and measured concentrations:

Dose range finding study was conducted with 6 concentrations of 0.19, 0.43, 0.94, 2.07, 4.55 and 10.0 mg/L; the main study was conducted at the test concentrations of 0.16, 0.31, 0.63, 1.25, 2.50, 5.00 and 10.00 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: Thoroughly cleaned rectangular glass aquaria having the water holding capacity of
50 liters.
- Type of flow-through: Proportional diluter
- Renewal rate of test solution: Test media will not be renewed until termination of the test.
- No. of organisms per vessel: 7
- Seven groups [1 control and 6 treatment groups] consisting of 7 fish in each group were used during the dose range finding study.
- Eight groups [1 control and 7 treatment groups] consisting of 7 fish in each group were used during the main study.
- A maximum loading of fish was 0.32 and 0.28 g wet weight of fish/L during dose range finding study and main study respectively.

TEST MEDIUM / WATER PARAMETERS
- Reverse Osmosis Water (RO Water) was used in the test.
- Total organic carbon: ≤ 2 mg/L

OTHER TEST CONDITIONS
- Adjustment of pH: Dose Range Finding Study: 7.15 to 7.47; Main Study: 7.26 to 7.55.
- Photoperiod: Photoperiod of 12 hour light and 12 hour darkness was maintained during dose range finding study and main study respectively.
- Light intensity: Dose Range Finding Study: 574 to 750; Main Study: 584 to 810.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Dose Range Finding Study 2.2; main study 2.0.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.87 mg/L

95% CI:

>= 0.333 - <= 1.406

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

Based on results of the dose range finding study, the main study was conducted at the tested concentrations of 0.16, 0.31, 0.63, 1.25, 2.50, 5.00 and 10.00 mg/L along with control group. The test concentrations were spaced using a geometric factor of 2.0.
During main study, no clinical signs of toxicity were observed in the control group and at the tested concentration of 0.16 mg/L during the 96 hours of exposure period.
Clinical sign of hypoactivity was observed at 54 hours and continued up to 96 hours exposure period at the tested concentration of 0.31 mg/L.
Clinical signs of abnormal horizontal orientation and hypoactivity were observed at 24 hours and continued up to 96 hours exposure period at the tested concentrations of 0.63 and 1.25 mg/L.
Clinical signs of abnormal horizontal orientation was observed at 24 hour exposure period and continued up to 54 hour exposure period. Clinical sign of hypoactivity and abnormal surface distribution/behavior was observed at 24 hour and 48 hour exposure period and continued up to 96 hours exposure period at the tested concentration of 2.50 mg/L.
Clinical sign of abnormal horizontal orientation was observed and ended at 24 hours exposure period, clinical signs of hypoactivity and abnormal surface distribution/behaviour were observed at 24 hours exposure period and continued up to 96 hours exposure period at the tested concentration of 5.00 mg/L.
Clinical sign of abnormal horizontal orientation was observed and ended at 24 hours exposure period, clinical signs of hypoactivity and abnormal surface distribution/behaviour were observed at 24 hours exposure period. However the clinical sign of hypoactivity was continued up to 78 hours and clinical sign of abnormal surface distribution/behavior was continued up to 72 hours exposure period respectively at the tested concentration of 10.00 mg/L.
No mortality was observed in control group and at the tested concentration of 0.16 mg/L during the 96 hours exposure period. Percent mortalities of 14.3, 28.6, 57.1, 71.4, 71.4 and 100.0% were observed at the tested concentrations of 0.31, 0.63, 1.25, 2.50, 5.00 and 10.00 mg/L of prop-2-yn-1-yl 1H-imidazole-1-carboxylate respectively during the 96 hour exposure period.

Reported statistics and error estimates:

The acute Median Lethal Concentration (LC50) of prop-2-yn-1-yl 1H-imidazole-1-carboxylate was evaluated by using Sigma Plot Version No.: 14 software with 95% confidence limits based on the nature of the mortality data. The LC50 values were evaluated with fiducial limits and graph was plotted with probit mortality against log concentration for recommended exposure periods of 96 hours.
Regression Equation
y = min + (max-min)/(1 + (x/LC50)^(-Hillslope))
y = 11.9217 + (72.5488-11.9217)/(1 + (x/0.8698)^(-3.0592))

Validity criteria fulfilled:

yes

Conclusions:

The 96 hours acute Median Lethal Concentration (LC50) value of prop-2-yn-1-yl 1H-imidazole-1-carboxylate is 0.8698 mg/L, with 95% confidence limits, lower limit of 0.3333 mg/L and upper limit of 1.4064 mg/L.

Executive summary:

The study was performed in accordance with the OECD Guidelines for Testing of Chemicals (Section 2), Effects on Biotic Systems, Guideline No. 203, “Fish Acute Toxicity Testing” adopted on 18 June 2019.

The objective of the study was to determine the toxicity of the test item prop-2-yn-1-yl 1H-imidazole-1-carboxylate on fish, Cyprinus carpio to determine 96 hours LC₅₀ value.

Based on results of the dose range finding study, the main study was conducted at the test concentrations of 0.16, 0.31, 0.63, 1.25, 2.50, 5.00 and 10.00 mg/L along with control group. The test concentrations were spaced using a geometric factor of 2.0.

No mortality was observed in control group and at the tested concentration of 0.16 during the 96 hours exposure period. Percent mortalities of 14.3, 28.6, 57.1, 71.4, 71.4 and 100.0 % were observed at the tested concentrations of 0.31, 0.63, 1.25, 2.50, 5.00 and 10.00 mg/L of prop-2-yn-1-yl 1H-imidazole-1-carboxylate respectively during the 96 hour exposure period.

The 96 hours acute Median Lethal Concentration (LC₅₀) value of prop-2-yn-1-yl 1H-imidazole-1-carboxylate is 0.8698 mg/L, with 95% confidence limits, lower limit of 0.3333 mg/L and upper limit of 1.4064 mg/L.

Description of key information

The test item, prop-2-yn-1-yl 1H-imidazole-1-carboxylate was tested for acute toxicity on fish, Cyprinus carpio.

The freshwater fish Cyprinus carpio was exposed over 96 hours to prop-2-yn-1-yl 1H-imidazole-1-carboxylate to determine the 96 hours Median Lethal Concentration (LC₅₀).

The 96 hours acute Median Lethal Concentration (LC₅₀) value of prop-2-yn-1-yl 1H-imidazole-1-carboxylate is 0.8698 mg/L, with 95% confidence limits, lower limit of 0.3333 mg/L and upper limit of 1.4064 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

0.87 mg/L