(E)-1,2-difluoroethylene

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental starting date: June 22 2020 Experimental completion date: June 24 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: "Testing Mthods 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:

Concentration of test item in the test solution
Frequency of measurement: At the stanrt and end of exposure

Sample for measurement:
Another solution, sampled separately from the preparation container (at the start of exposure)
One test vessel in each test vessel (at the end of exposure)

Volume of sample:
approximately 10 mL (all test levels; at the start of exposure)
Approximately 50 mL (all test levels; at the end of exposure)

Vehicle:

no

Details on test solutions:

After approximately 2L of dilution solution was added in 3L sampling bag for gas analysis (Tedler bag), about 500 mL gaseous test sample (approximately 10 minutes at about 5 mL/min) was enclosed in the bag. It was then shaken overnight at room temperature to prepare the stock solution. At the day that the test solution of 250 mg/L was prepared, test item concentrations of stock solution was measured. The measured concentration of the test item in the stock solution was 909 mgL. Required volumes of the stock solution and dilution water were mixed and stirred in a preparation container to prepare the test solution which was divided into each test vessel.

Test organisms (species):

Daphnia magna

Details on test organisms:

Supplier: The University of Sheffield, UKAcclimation: Young dapnids produced by parents that were cultured in the test facility were used. The parents to obtain young daphnids were bred in the same quality of water (dechlorinated tap water), water temperature (20 +/-1°C) and photoperiod (16-hour light, 8-hour dark) as used in the study. The parent animals used for the test were from the same lot and ther age and survival rate were 24-day old and 100 % respectively/
Chlorella vulgaris of 0.1 - 0.2 mgC/day per Daphnia was fed to the parents once oer day.

Allocation: random sampling

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

40 mg/L CaCO3

Test temperature:

20 +- 1°C

pH:

7.9
no adjustment

Dissolved oxygen:

Dissolved oxygen meter
>/= 3 mg/L without aeration

Salinity:

Not applicable as freshwater study

Conductivity:

17 mS/m

Nominal and measured concentrations:

250 mg/L nominal concentration
170 mg/L as measured concentration

Details on test conditions:

Test vessel: 50 mL stoppered Erlenmeyer flask (closed vessel)
Replicate: 4 replicates per test vessel
Number of organisms: 20 daphnids/test level (5 daphnids/test vessel)
Volume of test solution: Approximately 200 mL/test level (approximately 50 mL/test vessel)

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

Observation and measurement
a) Observation of test organisms
Observations of immobility and symptoms of the test organisms were conducted at 24 and 48 hours after exposure.
b) Appearance of test solution
Observation at the start and end of exposure
c) Condition of test solution
Frequency of measurement: At the start and end of exposure

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 170 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Immobility:
Immobility in the exposure level was 5%, which met the requirement for the limit test i.e. not more than 10%. Immobility in the control was 0%, which met the criterion for the validity of the test i.e. not more than 10%.

Observed abnormal response:
In the exposure level, one daphnid (5% of the test organisms) showed immobilization, including lethargy. However, other daphnids did not show any abnormal responses (e.g. discolour of body, trapping at the surface of the water), which met the requirement for the limit test i.e. not more than 10%.

In the control, no abnormal response was observed during exposure, which met the criterion for the validity of the test.

Concentration of the test item in test solution:
The measured concentrations of the test item in the test solution at the start and end of exposure were 170 mg/L together, and the time-weighted mean of the measured concentrations was 170 mg/L.

Observation and measurement of test solution:
Appearance of test solution: The test solutions in the exposure level and the control were colorless and clear at the start and end of exposure.

Condition of test solution:
The measured values of dissolved oxygen concentration, pH and temperature of the test solutions during exposure were 7.7 - 8.2 mg/L, 7.5 - 7.6 and 20.0 - 20.2°C. The measured values of dissolved oxygen concentration met the criterion for the validity of the test (greater than 3 mg/L at the end of exposure).

Results with reference substance (positive control):

A 48-hour acute immobilization test with potassium dichromate was periodically conducted. The latest data gave a result of 48-h EC50 0.12 mg/L. This value was within the stipulated range for the test facility.

Immobility:

Measured concentration (mg/L)	Vessel	24 hours		48 hours
		No of immobilized daphnids/Total daphnids	Immobility (%)	No of immobilized daphnids/Total daphnids	Immobility (%)
Control	A	0 / 5	0	0 / 5	0
	B	0 / 5		0 / 5
	C	0 / 5		0 / 5
	D	0 / 5		0 / 5
170	A	0 / 5	0	1 / 5	5
	B	0 / 5		0 / 5
	C	0 / 5		0 / 5
	D	0 / 5		0 / 5

 

Validity criteria fulfilled:

yes

Conclusions:

The 48-hr EC50 of the test item for Daphnia magna is >170 mg/L.

Executive summary:

The objective of the study was to determine the 48 -hr EC50 of the test material by conducting an acute immobilization study of TKN1 in Daphnia magna. The test guideline followed was OECD Guidelines for Testing of Chemicals No. 202, April 13, 2004, "Daphnia sp., Acite Immobilisation Test".

20 daphnids were exposed to a nomnal concentration of 250 mg/L (170 mg/L as measured concentration) for a period of 48 hours, using a static regime, and closed system without headspace.

The 48 Hr EC50 was determined to be >170 mg/L, based on the time-weighted mean of measured concentrations.

Description of key information

 

The objective of the study was to determine the 48 -hr EC50 of the test material by conducting an acute immobilization study of TKN1 in Daphnia magna. The test guideline followed was OECD Guidelines for Testing of Chemicals No. 202, April 13, 2004, "Daphnia sp., Acite Immobilisation Test".

 

20 daphnids were exposed to a nominal concentration of 250 mg/L (170 mg/L as measured concentration) for a period of 48 hours, using a static regime, and closed system without headspace.

 

The 48 Hr EC50 was determined to be >170 mg/L, based on the time-weighted mean of measured concentrations.

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 invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 170 mg/L