3-Fluorphenylboric acid

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05 Dec 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

All concentration levels and the control were analytically verified at the start (0 h) and at the end of exposure (72 h) with algae.

Vehicle:

yes

Remarks:

water

Details on test solutions:

A stock preparation with a test item concentration of 100 mg/L was freshly prepared. Out of the stock solution 5 concentration levels were tested in a geometrical series with a dilution factor of 0.2, 0.632, 2.0, 6,32 and 20 mg/L (nominal). The concentration levels are based on the results of a preliminary range finding test.

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

Test organism: Pseudokirchneriella subcapitata HINDAK, SAG 61.81
Origin: Sammlung von Algenkulturen (SAG), Pflanzenphysiologisches Institut der Universität Göttingen, Göttingen, Germany

ACCLIMATION
- Acclimation period: not required
- Any deformed or abnormal cells observed: no

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

22.0-23.5 °C

pH:

7.73 - 8.85

Nominal and measured concentrations:

Nominal concentrations: 0.2, 0.632, 2.0, 6,32 and 20 mg/L
Measured concentrations after 0h: 0.213, 0.656, 2.05, 6.70, 20.8 mg/L
Measured concentrations after 72h: 0.207, 0.647, 2.06, 6.81, 21.4 mg/L

Details on test conditions:

The algal biomass in each flask was determined daily during the exposure period via Chlorophyll a-fluorescence. Microscopic evaluation of the cells at the start and at the end of the incubation period was carried out.
TEST SYSTEM
- Test vessel: Sterile Erlenmeyer flasks (vol. 250 mL) with cotton wool plugs
- Type: open
- Material, fill volume: glass, 100 mL
- Aeration: no
- Initial cells density: 6839 cells/mL
- Control end cells density: 2559585 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes, according to the guideline

TEST MEDIUM / WATER PARAMETERS
- Preparation of dilution water: according to the guideline

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 24 hours/day light
- Light intensity and quality: Approximately 4440 to 8880 lux, corresponding to 60 to 120 µE*m-2*s-1

EFFECT PARAMETERS MEASURED
- Determination of cell concentrations: The cell density was measured daily via Chlorophyll a- fluorescence, excitation at 436 nm, emission at 685 nm. Dilution water was used as a background signal.
Microscopic evaluation of the cells at the start and the end of the incubation period was carried out. The cells were checked for unusual cell shapes, colour differences, differences in chloroplast morphology, flocculation, adherence of algae to test containers and agglutination of algae cells.
The pH-values at the start of exposure were measured in one additional replicate of each test item concentration and the control. At the end of exposure, the pH-values were measured from pooled samples of each test item concentration and the control. The room temperature was measured continuously. Light intensity was measured prior to the start of exposure.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: √10
- Range finding study
- Test concentrations: 1, 10, 100 mg/L
- Results used to determine the conditions for the definitive study: yes, EC50 between 1 and 10 mg/L

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

6.45 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.986 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.19 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.105 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 0.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Results with reference substance (positive control):

The toxicity of potassium dichromate (SIGMA, batch number MKBV0900V, purity 99.0 %, CAS RN 7778-50-9) to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined over a period of 72 hours from 2017-10-10 to 2017-10-13. The reference item toxicity is in the valid range following test facility SOPs. The EC50 based on growth rate was 0.535 mg/L (Validity range: 0.747 ± 0.524), the EC50 based on yield was 0.320 mg/L (Validity range: 0.398 ± 0.291).

Reported statistics and error estimates:

The NOEC and LOEC were determined by calculation of statistically significant differences of growth rates and yield. As a standard, One Way Analysis of Variance (ANOVA) and Dunnett's test were used for NOEC/LOEC calculations. When running a One Way Analysis of Variance, a Normality test and an Equal Variance test were done first. P-values for both Normality and Equal Variance tests are 0.05. The α-value (acceptable probability of incorrectly concluding that there is a difference) is α=0.05.

Validity criteria fulfilled:

yes

Conclusions:

The test item was found to inhibit the growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 hours with the following effect values (based on the nominal test item concentrations): The EC50 for growth rate and yield were 6.45 and 1.19 mg/L. The EC10 (72 h) value for inhibition of growth rate is 0.986 mg/L.

Executive summary:

The toxicity of the test item to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD 201 and Council Regulation (EC) No 266/2016 C.3. The aim of the study was the determination of NOEC, LOEC, EC10 and EC50-values of growth rate and yield over a period of 72 hours. The study was conducted under static conditions with an initial cell density of 6839 cells/mL. A stock solution with a nominal test item concentration of 100 mg/L was freshly prepared with dilution water. Out of the stock solution five concentration levels were tested in a geometrical series: 0.200 - 0.632 - 2.00 - 6.32 - 20.0 mg/L. Three replicates were tested for each test item concentration and six replicates for the control. The environmental conditions were within the acceptable limits. The concentrations of the test item were determined at the start of the exposure (0 hours) and at the end of the exposure (72 hours) of all tested solutions and the control via HPLC-DAD. The measured concentrations of the test item were between 103% and 106% of the nominal concentration at the start of the exposure (0 hours) and between 102 and 108% at the end of the exposure (72 hours). Therefore all effect values given are based on the nominal test item concentrations. The test item was found to inhibit the growth of the freshwater green after 72 hours with the following effect values: The EC50 for growth rate and yield were 6.45 and 1.19 mg/L, for EC10 0.986 and 0.105 mg/L. The EC10 (72 h) value for inhibition of growth rate is 0.986 mg/L.

Description of key information

The test item was found to inhibit the growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 hours with the following effect values (based on the nominal test item concentrations): The EC50 for growth rate and yield were 6.45 and 1.19 mg/L. The EC10 (72 h) value for inhibition of growth rate is 0.986 mg/L. (reference 6.1.5-1).

Key value for chemical safety assessment

EC50 for freshwater algae:

6.45 mg/L

EC10 or NOEC for freshwater algae:

0.986 mg/L

Additional information

The toxicity of the test item to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD 201 and Council Regulation (EC) No 266/2016 C.3. The aim of the study was the determination of NOEC, LOEC,EC10and EC50-values of growth rate and yield over a period of 72 hours. The study was conducted under static conditions with an initial cell density of 6839 cells/mL. A stock solution with a nominal test item concentration of 100 mg/L was freshly prepared with dilution water. Out of the stock solution five concentration levels were tested in a geometrical series: 0.200 - 0.632 - 2.00 - 6.32 - 20.0 mg/L. Three replicates were tested for each test item concentration and six replicates for the control. The environmental conditions were within the acceptable limits. The concentrations of the test item were determined at the start of the exposure (0 hours) and at the end of the exposure (72 hours) of all tested solutions and the control via HPLC-DAD. The measured concentrations of the test item were between 103% and 106% of the nominal concentration at the start of the exposure (0 hours) and between 102 and 108% at the end of the exposure (72 hours). Therefore, all effect values given are based on the nominal test item concentrations. The test item was found to inhibit the growth of the freshwater green after 72 hours with the following effect values: The EC50 for growth rate and yield were 6.45 and 1.19 mg/L, for EC10 0.986 and 0.105 mg/L.

The EC10 (72 h) value for inhibition of growth rate is 0.986 mg/L. (reference 6.1.5-1).