1-(3,5-Dichloro-4-fluoro-phenyl)-2,2,2-trifluoro-ethanone

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

effects on growth of green algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From April 20 to April 23, 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch number: 1930461
Purity: 97.3%

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0.10, 0.32, 1.0, 3.2 and 10 mg/L
- Sampling method: Analysis of the concentration of the test item was performed by GC in 0 hour fresh solution and 72 hours old solutions in control and each test group.
- Sample storage conditions before analysis: stored in a refrigerator (2-8 °C)

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution of test item at a nominal concentration of 100 mg/L was prepared with OECD alga growth medium. 0.0501 g of test item was weighed and dissolved in 500 mL of growth medium by magnetic stirring for about 3 hours. After the test item was dissolved completely, the solution was used to dilute test solutions. Pipette 0.50, 1.6, 5.0, 16 and 50 mL of the stock solution and make up to 500 mL with OECD alga growth medium. The solutions were mixed thoroughly, resulting in test solutions at 0.10, 0.32, 1.0, 3.2 and 10 mg/L.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: freshwater alga
- Strain: Desmodesmus subspicatus
- Source (laboratory, culture collection): The stock alga was originally introduced from Institute of Hydrobiology, Chinese Academy of Sciences
- Age of inoculum (at test initiation): four days
- Method of cultivation:

ACCLIMATION
- Acclimation period: four days
- Culturing media and conditions (same as test or not): same
- Any deformed or abnormal cells observed:

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

21-24 oC

pH:

7.59 - 7.80

Nominal and measured concentrations:

Nominal concentrations: 0.10, 0.32, 1.0, 3.2 and 10 mg/L;
Meansured concentrations: 0.081, 0.254, 0.803, 2.24 and 7.42 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: flask
- Type (delete if not applicable): open / closed
- Material, size, headspace, fill volume: 500 mL
- Renewal rate of test solution (frequency/flow rate): no
- Initial cells density: 5E+03 cell/mL
- Control end cells density: 5.49E+05 cell/mL
- No. of organisms per vessel:
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- No. of vessels per vehicle control (replicates):

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used:

OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH: no
- Photoperiod:
- Light intensity and quality: 4440-8880 Lux
- Salinity (for marine algae):

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: manual cell counting with microscope

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations: 0.1, 1, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study:

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

4.1 mg/L

95% CI:

1.2 - 13.6

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.081 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.82 mg/L

95% CI:

0.48 - 1.4

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

yield

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.081 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

yield

Details on results:

During the 72-hour test duration, there was no abnormal appearance of the algae observed in control replicates and replicates of each test group. After 72 hours exposure, comparing with the control group, the test groups showed increasing inhibition effects with increasing concentration. There was no significant difference in algae growth rate and growth yield between the control group and the nominal concentration of 0.10 mg/L test group (p>0.05, t-test).

Results with reference substance (positive control):

72 hour EyC50 of 3,5-DCP to Desmodesmus subspicatus was 2.0 mg/L with the 95% confidence limits 2.0 - 2.1 mg/L and 72 hour ErC50 was 2.6 mg/L with the 95% confidence limits 2.5 - 2.8 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

The 72-hour effect concentration of average specific growth rate (ErCx) of and yield (EyCx) of the test item to Desmodesmus subspicatus was calculated as: ErC50 is 4.1 mg/L, EyC50 is 0.82 mg/L, NOEC for growth rate and yield is 0.081 mg/L.

Executive summary:

An alga growth inhibition study of PF-06458663 (Trifluoroketone) was conducted over a 72-hour exposure period in a static system, according to OECD Guideline 201 under GLP.

The 72-hour effect concentration of average specific growth rate (ErCx) of and yield (EyCx) of the test item to Desmodesmus subspicatus was calculated as: ErC50 is 4.1 mg/L, EyC50 is 0.82 mg/L, NOEC for growth rate and yield is 0.081 mg/L.

Description of key information

The 72-hour effect concentration of average specific growth rate (ErCx) of and yield (EyCx) of the test item to Desmodesmus subspicatus was calculated as: ErC50 is 4.1 mg/L, EyC50 is 0.82 mg/L, NOEC for growth rate and yield is 0.081 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

4.1 mg/L

EC10 or NOEC for freshwater algae:

0.081 mg/L

Additional information

An alga growth inhibition study of PF-06458663 (Trifluoroketone) was conducted over a 72-hour exposure period in a static system, according to OECD Guideline 201 under GLP.

The 72-hour effect concentration of average specific growth rate (ErCx) of and yield (EyCx) of the test item to Desmodesmus subspicatus was calculated as: ErC50 is 4.1 mg/L, EyC50 is 0.82 mg/L, NOEC for growth rate and yield is 0.081 mg/L.