1,3-Dioxole, 2,2,4-trifluoro-5-(trifluoromethoxy)

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:

February 21st, 2017 to October 2nd, 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

OECD guideline 202, Daphnia sp., Acute Immobilisation Test (2004).

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

Temperature deviated from the optimal range as prescribed by the study plan. Inadvertently, single samples were taken for analysis at the start of the study whereas the study plan asked for duplicate.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

605-263-0

EC Number:

605-263-0

Cas Number:

161611-74-1

Molecular formula:

C4F6O3

IUPAC Name:

605-263-0

Test material form:

liquid

Details on test material:

- Physical state: Colourless liquid; odorless
- Storage condition of test material: At room temperature

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: lot BLT 06 - 14 (0629 SE)
- Expiration date of the lot/batch: October 2020

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: The test material must be kept at room temperature in a pressurized container.

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: A test solution was prepared at an initial loading rate of 150 mg/L. Test solution preparation was performed in an incubator at 17°C and included slow magnetic stirring for 2 days to produce a Saturated Solution (SS), while preventing evaporation. Subsequently, a settlement period of 3½ hours was applied to ensure that undissolved test item settled on the bottom of the flask. The SS was collected by means of siphoning the upper part directly into a number of test beakers which were completely filled.

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentration of the test vessel was checked before the beginning of the test and was not as expected. A test limit at 150 mg/L of test substance was performed.
- After 24 hours, the concentration of the test substance in the test vessel was measured twice
- The concentration was again measured twice in a freshly prepared solution (duplicate analysis)

Test sample:
The samples were analyzed in duplicate on the day of sampling. 100 µL of the sample was transferred into a 10 ml vial containing 4900 µL ISO and 50 µL acetone through the septum of the vial with a syringe. After 5 minutes of incubation at 60°C, the headspace was analysed

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A test solution was prepared at an initial loading rate of 150 mg/L (no correction was made for the purity of the test item). The loading was above the regulatory limit as it was anticipated that it was very difficult to get and maintain the test item in solution. The test medium was cooled to a temperature of 17°C as to avoid boiling of the test item. A one-litre glass flask was filled for ¾ with the test medium. The test item (96 µl) was then introduced into the flask (using a pipette) and directly thereafter the flask was completely filled with cooled test medium leaving no headspace. Subsequently, slow magnetic stirring for 2 days was applied in an incubator set at 17°C to ensure a Saturated Solution (SS) of the test item was reached in test medium, while preventing evaporation. Subsequently, a settlement period of 3½ hours was applied to ensure that undissolved test item settled on the bottom of the flask. The SS was then collected by means of siphoning the upper part directly into a number of 42.5 mL P&T vials which were completely filled and closed. All test solutions were clear and colorless at the end of the preparation procedure.

- Control: Test medium without test item or other additives.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Food type: suspension of fresh water algae
- Frequency: daily, before the test

Study design

Test type:

semi-static

Water media type:

other: tap water purified by reverse osmosis

Limit test:

yes

Total exposure duration:

24 h

Remarks on exposure duration:

100 % of the daphnids were immobilized after 24 hours. Consequently, the test could not run for 48 hours.

Test conditions

Hardness:

180 mg/L

pH:

7.7 +/- 0.3

Nominal and measured concentrations:

A limit test at 150 mg/L was performed. The initial measured concentration before the start of the test was 1.95 mg/L. 24 hours later, the concentration was measured, with duplicate samples: 1.31 and 1.40 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: Purge and trap vials (Open Top VOA Vial Assembled w/Bonded P201TFE/Silicone Septa Cap) of ~42.5 mL content, airtight closed with a septum and parafilm, no headspace.
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: no headspace
- Aeration: No
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

OTHER TEST CONDITIONS
- Photoperiod: 16h light / 8 hours dark

Reference substance (positive control):

yes

Remarks:

Potassium dichromate was used as positive control.

Results and discussion

Effect concentrations

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

<= 1.95 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Due to the technical difficulties encountered during the initial project of exposing Daphnia magna to the test item for 48 hours, it was not possible to generate reliable analytical results to calculate the 48h-EC50. It was however concluded that it is highly likely that the 48h-EC50 is below 1.95 mg/L according to the values of the measured concentrations over the 1st 24 hours of the test, which caused 100% immobilisation of daphnids.

Results with reference substance (positive control):

- Results with reference substance (potassium dichromate) : The 24h-EC50 was 0.64 mg/L for the test substance with a 95% confidence interval between 0.56 and 0.73 mg/L. The 48h-EC50 reference substance 48h-EC50 was 0.48 mg/L with a 95% confidence interval between 0.43 and 0.53 mg/L.

Any other information on results incl. tables

Table 1 : Incidence of immobility in the Limit Test

Perfluoro methoxy dioxole Loading rate (mg/L)	Vessel number	Number Daphnia exposed	Response at 24 h
			Number	Total %
Control	A B C D	5 5 5 5	0 0 0 0	0
150	A B C D	5 5 5 5	5 5 5 5	100^#

 ^#Microscopic observation revealed that daphnids were all dead

Table 2 : Final test, test samples

Time of sampling (hours)	percentage of SS (1) (%)	Analyzed concentration (mg/L)	Relative to initial [%]
0	0 100	0.00061 (2) 1.95
24 (old)	0 0 100 100	0.00045 (2)  0.00031 (2) 1.40 1.31	75 50 72 67
24 (fresh)	0 0 100 100	0.00031  (2) 0.00032  (2) 0.056  (2) 0.030  (2)

(1) Percentage of saturated solution prepared at loading rate of 150 mg/L.

(2) Estimated value, calculated using the mean response factor of the lowest calibration solution.

Applicant's summary and conclusion

Validity criteria fulfilled:

no

Remarks:

Measurement of the quality control samples showed very high variability (varied between 10 and 66 %) and did not meet the SANCO criterion of 70-100 % recovery.

Conclusions:

Effect concentrations could not be determined as the test was stopped before the end. No options were found to improve the analytical method. It was not possible to perform a final test producing toxicity values based on reliable analytical results because of the high volatility, low boiling point and poor solubility of the test item.
It was however concluded that it is highly likely that the 24h-EC50 is below 1.95 mg/L according to the values of the measured concentrations over the fisrt 24 hours of the test, which caused 100% immobilisation of daphnids.

Executive summary:

The influence of the test substance on immobilisation of Daphnia magna was investigated according to OECD Guideline 202. Daphnids were exposed to the test item under semi-static conditions, for 24 hours.

A test limit at 150 mg/L was performed. The initial measured concentration of test substance was only 1.95 mg/L. All the daphnids exposed to this concentration of test substance were immobile after 24 hours of exposure, whereas all the daphnids exposed to the control were still mobile. Microscopic observation revealed that the immobilised daphnids had deceased. The experiment was consequently stopped and effect concentrations could not be determined. In conclusion, due to the technical difficulties it was not possible to generate reliable results to calculate the effect concentration. It was however concluded that it is highly likely that the 24h-EC50 is below 1.95 mg/L according to the values of the measured concentrations over the first 24 hours of the test, which caused 100% immobilisation of daphnids.