(E)-1,2-difluoroethylene

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:

Experimental starting date: June 22 2020 Experimental completion date: June 26 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: "Fish, Acute Toxicity Test" stipulated in the "Testing Methods for New Chemical Substances" of Japanese Chemical substances Control Law .

Version / remarks:

Latest revision July 1, 2019

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Chemical name; (E)-1,2,-Difluoroethylene
Other name: TKN1

Purity of test item: 99.9989% (GC area)

Colourless gas
Flammable, stable in dark storage space at room temperature

Analytical monitoring:

yes

Details on sampling:

The test solution for analysis (approximately 10 mL - all test levels) was taken out from the middle layer of the test vessel.

Vehicle:

no

Details on test solutions:

Preparation of test solution
After approximately 2 L of dilution water was added in 3 L sampling bag for gas analysis (Tedlar bag), about 500 mL gaseous test sample (approximately 10 minutes at about 50 mL/min) was enclosed in the bag. It was then shaken overnight to prepare the stock solution. After shaking, the test item concentration in the stock solution was measured. As a result, the stock solutions of 649 and 1080 mg/L were prepared at the start of exposure and before renewal at the 48 hours, respectively. Required volumes of the stock solution and dilution water were mixed in the test container, and stirred to prepare the test solution of 300 mg/L. The stock solution and the test solution were prepared at the start of exposure and the renewal after 48 hours.

Test organisms (species):

Oryzias latipes

Details on test organisms:

supplier: CERI Kurume (in-test facility production)
Total length: 2.0 +/- 1.0 cm
Allocation: random sampling

Acclimation
Age at the start of exposure: 1 month
Water: Dechlorinated tap water
Dissolved oxygen concentration: At least 80% of air saturation value
Temperature: 24 +/1 1°C
Lighting condition: Room light - 16-hour light/ 8-hour dark
Feed: Newly hatched Artemia nauplii
Feeding amount and frequnecy: Saturation volume, every daya
No use of medicant for external disnfection
Duration of acclimation: 17 days
Moratlity of test group: 0%
Feed withdrawal: 24 hours before the start of exposure

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

40 mg/L of CaCO3

Test temperature:

23°

pH:

pH meter HM-21P (DKK-TOA)
7.9

Dissolved oxygen:

Instrument: Dissolved oxygen meter HQ30d
7.9 mg/L at start of study
6.7 mg/L at end of study

Salinity:

Not applicable as freshwater study

Conductivity:

17 mS/m

Nominal and measured concentrations:

300 mg/L (nominal concentration) as limit test
138 mg/L as measured concentration
The test concentration was derived from the results of the preliminary study.

Details on test conditions:

Type of test: Semi-static regime (renewal whole test solution at 48 hours after the start of exposure), closed system with headspace
Test vessel: 3 L glass closed tank
Cover on test vessel: Airtight transparent plastic lid

Replicate: 1 replicate/test vessel
Number of fish per test vessel: 7
Volume of test solution: approximately 2.7 L per test vessel.
Aeration: No aeration
pH adjustment: No pH adjustment
Lighting condition: Room light, 16-hr light/8-hour dark
Feeding: no feeding


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:Dechlorinated tap water
- Total organic carbon: <0.5 mg/L
- Particulate matter: <1 mg/L
- Chlorine: <0.02 mgL
- Alkalinity: 41 mg/L CaCO3

Obsevation and measurement
a) Mortality and visible abnormality were observed at 3, 24, 48, 72 and 96 hours after the start of exposure.
b) Total length and body weight of test organism
c) Appearance of test solution
d) Condition of test solution
e) Concentration of test item in test solution

Reference substance (positive control):

yes

Remarks:

Copper (II) sulphate pentahydrate

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 138 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

Mortality
Number of dead fish in the control at the end of exposure was 0.
Number of dead fish at the end of the exposure was zero.

Observed performance status
No abnormal response was observed in the control
No abnormal response in the exposure level during exposure was observed.

Size of test organism
Total length: 2.0 +/- 0.1 cm 91.9 - 2.2 cm)
Body weight: 0.074 +/- 0.009 (0.067 - 0.092 g)

Observation of test solution:
The test solutions in all test levels were colorless and clear at the start and before the renewal.

Conditions of test solution:
The measured values of dissolved oxygen concentration, pH and temperature during exposure were 6.6 - 8.4 mg/L, 7.1 -7.6 and 24.0 - 24.5°C.
The measured values of dissolved oxygen concentration met the criterion for the validity of the test (at least 60% of saturate concentration at the water temperature).

Concentration of test item in test solution: The measured concentrations of the test item in the test solutions were 267 and 176 mg/L at the start of exposure and after the renewal, and 92.9 and 65.1 mg/L before the renewal and at the end of exposure were 34.8 and 37.0% of the concentrations at preparation. The time-weighted mean of the measured concentrations was 138 mg/L.

Results with reference substance (positive control):

A 96-hour acute toxicity test with reference substances is periodically conducted. The latest test with Copper (II) sulfate pentahydrate gave a result of 96-hr LC50 0.43 mg/L. This value was within the stipulated range of the test facility.

Sublethal observations / clinical signs:

Cumulative Morality

Measured concentration (mg/L)*	Cumulative mortality (%)
	3 hours	24 hours	48 hours	72 hours	96 hours
Control	0	0	0	0	0
138	0	0	0	0	0

*Time-weighted mean of the measured concentrations

Validity criteria fulfilled:

yes

Conclusions:

The 96-hour LC50 of the test item for Medaka was >138 mg/L.

Executive summary:

The objective of the study was to determine the 96 -hr LC50 by conducting an acute toxicity study of TKN1 in Medaka.The test guideline followed was OECD Guidelines for Testing of Chemicals, No. 203, July 17, 1992, "Acute fish Toxicity Test".

Seven fish were exposed to 300 mg/L nominal concentration (148 mg/L measured concentration) for a period of 96 hours under semi-static conditions

No effects were observed on the test organisms, and the time-weighted mean of the measured concentrations during the exposure period was 138 mg/L, so the 96 -hour LC50 was > 138 mg/L. The environmental conditions were within the suitable range. Therefore, it is concluded that this study complied with the applied test guidelines.

Description of key information

 

The objective of the study was to determine the 96 -hr LC50 by conducting an acute toxicity study of TKN1 in Medaka.The test guideline followed was OECD Guidelines for Testing of Chemicals, No. 203, July 17, 1992, "Acute fish Toxicity Test".

 

Seven fish were exposed to 300 mg/L nominal concentration (148 mg/L measured concentration) for a period of 96 hours under semi-static conditions (renewal at 48 hrs) in a closed system with headspace.

 

No effects were observed on the test organisms, and the time-weighted mean of the measured concentrations during the exposure period was 138 mg/L, so the 96 -hour LC50 was > 138 mg/L.

The environmental conditions were within the suitable range. Therefore, it is concluded that this study complied with the applied test guidelines.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

> 138 mg/L