Methyl (R)-2-(4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy)propionate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

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

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: U.S. EPA - FIFRA Pesticide Assessment Guidelines Subdivision J, Hazard Evaluation: Non-target Plants Guideline 123-2

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

DE-535
Substance ID: NB10150401
Purity: 98.4%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

acetone

Test organisms (species):

other: Selenastrum capricornutum Printz

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

4 d

Test temperature:

24.0 ± 0.4 °C (23.8 °C-24.8 °C)

pH:

7.4 to 7.6 without algae and from 7.6 to 8.0 with algae

Nominal and measured concentrations:

Nominal: 0 (medium), 0 (acetone), 0.313, 0.625, 1.25, 2.5, 5.00, 10.0 mg/L
Measured: 0.261, 0.500, 0.876, 0.641, 3.87, 2.44 mg/L

Duration:

4 d

Dose descriptor:

other: EC25

Effect conc.:

> 3.87 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: ester equivalent

Basis for effect:

other: algal growth

Remarks on result:

other: highest dose tested

Key result

Duration:

4 d

Dose descriptor:

EC50

Effect conc.:

> 3.87 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: ester equivalent

Basis for effect:

biomass

Remarks on result:

other: highest dose tested

Key result

Duration:

4 d

Dose descriptor:

EC50

Effect conc.:

> 3.87 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: ester equivalent

Basis for effect:

growth rate

Remarks on result:

other: highest dose tested

Duration:

4 d

Dose descriptor:

EC50

Effect conc.:

> 3.87 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: ester equivalent

Basis for effect:

other: algal growth

Remarks on result:

other: highest dose tested

Duration:

4 d

Dose descriptor:

NOEC

Effect conc.:

2.44 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: ester equivalent

Basis for effect:

other: algal growth

Validity criteria fulfilled:

yes

Conclusions:

3-4 d ErC50 (green algae): >3.87 mg/L (highest dose tested)
3-4 d EbC50 (green algae): >3.87 mg/L (highest dose tested)
3-4 d NOEC (green algae): 2.44 mg/L (algal growth)

Executive summary:

The purpose of this study was to assess the effects of test substance on the growth Selenastrum capricornutum, Printz, a freshwater green alga. These data were used to determine the EC50 and EC25 values (those concentrations that limited growth of this algal species to 50%, and 25% of the test population when compared to the control population, respectively). The EbC50 value (the concentration that inhibits of growth of this species to 50% of the test population when compared to the control population), the ErC50 value (the concentration that inhibits the growth rate of this species to.50% of the test population when compared to the control population) and a no-observed-effect concentration (NOEC) were also determined. The study was performed according to U S EPA 123-2, OECD guideline 201 and EEC C.3.

The freshwater algae were exposed to mean analyzed equivalent test substance concentrations of 0.261, 0.500, 0.641, 0.876, 2.44, and 3.87 mg/L over a 4-day period. Undissolved test substance was observed in the neck of the volumentric flask used to prepare the following dose levels of 0.641, 0.876, 2.44 and 3.87 mg/L. Treatment, assay medium control group (negative control) and the acetone solvent control (100 µL/L) group were all set in triplicate, with an initial average cell density of 10101 cells/mL (range of 6119-12565 cells/mL).

Effects of test substance on algal growth were based on the average analyzed methyl ester equivalent concentrations (ester plus acid, as ester equivalents) at each dose level. The effects of on cell growth after three days of exposure, relative to the combined control groups, ranged from 5.3% stimulation of growth at 0.261 mg/L to 20.0% inhibition of growth at 3.87 mg/L. The effects on cell growth after four days of exposure relative to the combined control groups, ranged from 3.3% stimulation of growth at 0.500 mg/L to 16.9% inhibition of growth at 3.87 mg/L.

The 3- and 4-day EC50 values for inhibition of growth were greater than a mean analyzed concentration of 3.87 mg/L. Similarly, the 3- and 4-day ErC50 values for growth rate, the 3- and 4-day EC25 values, and the 3- and 4-day EC50 values for algal growth was greater than a mean analysed concentration of 3.87 mg/L. The statistically derived 3- and 4-day no-observable effect concentration was 2.44 mg/L.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: U.S. EPA - FIFRA Pesticide Assessment Guidelines Subdivision J, Hazard Evaluation: Non-target Plants Guideline 123-2

GLP compliance:

yes

Specific details on test material used for the study:

DE-535 (methyl ester)
Substance ID: NB10150101, TSN101748
Purity: 98.4%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

acetone

Test organisms (species):

Navicula pelliculosa

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

5 d

Test temperature:

23.8 ± 0.3 °C (23.5 °C-24.3 °C)

pH:

6.7 to 7.4 without diatoms and from 7.2 to 7.4 with diatoms

Nominal and measured concentrations:

Nominal: 0 (medium), 0 (acetone), 0.365, 0.731, 1.46, 2.92, 5.85, 11.7 mg/L
Measured:

Duration:

5 d

Dose descriptor:

other: EC25

Effect conc.:

1.52 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: ester equivalent

Basis for effect:

other: diatom growth

Remarks on result:

other: 95% CI: 0.02-3.03 mg/L

Key result

Duration:

5 d

Dose descriptor:

EC50

Effect conc.:

1.72 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: ester equivalent

Basis for effect:

other: inhibition of growth

Remarks on result:

other: 95% CI: 0.48-6.11 mg/L

Key result

Duration:

5 d

Dose descriptor:

EC50

Effect conc.:

5.37 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: ester equivalent

Basis for effect:

growth rate

Duration:

5 d

Dose descriptor:

EC50

Effect conc.:

2.55 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: ester equivalent

Basis for effect:

other: diatom growth

Remarks on result:

other: 95% CI: 1.00-4.09 mg/L

Duration:

5 d

Dose descriptor:

NOEC

Effect conc.:

1.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: ester equivalent

Basis for effect:

other: diatom growth

Validity criteria fulfilled:

yes

Conclusions:

5 d ErC50 (diatom): 5.37 mg/L
5 d EbC50 (diatom): 1.72 mg/L
5 d NOEC (diatom): 1.10 mg/L (diatom growth)

Executive summary:

The purpose of this study was to assess the effects of test substance on the growth Navicula pelliculosa, a freshwater diatom. These data were used to determine the EC50 and EC25 values (those concentrations that limited growth of this species to 50%, and 25% of the test population when compared to the control population, respectively). The EbC50 value (the concentration that inhibits of growth of this species to 50% of the test population when compared to the control population), the ErC50 value (the concentration that inhibits the growth rate of this species to.50% of the test population when compared to the control population) and a no-observed-effect concentration (NOEC) were also determined. The study was performed according to U S EPA 123-2.

The freshwater diatoms were exposed to mean analyzed equivalent test substance concentrations of 0.271, 0.552, 1.10, 1.60, 2.73, and 3.36 mg/L over a 5-day period. Treatment, assay medium control group (negative control) and the acetone solvent control (100 µL/L) group were all set in, with an initial average cell density of 26438 cells/mL (range of 23990-34628 cells/mL).

Effects of test substance on diatom growth were based on the average analyzed methyl ester equivalent concentrations (ester plus acid, as ester equivalents) at each dose level. The effects on diatom growth after five days of exposure, relative to the combined control groups, ranged from 9.9% stimulation of growth at 0.552 mg/L to 96.6% inhibition of growth at 3.36 mg/L.

The measured 5-day EbC50 value for this species of diatom was 1.72 mg/L. The 5-day ErC50 value was 5.37 mg/L. The 5-day EC25 and EC50 values were 1.52 mg/L and 2.55 mg/L, respectively, and the 5-day NOEC was 1.10 mg/L.

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

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:

yes

Remarks:

Experimental Conditions; Test Concentrations (the pre-tests were not performed in compliance with the GLP guidelines).

GLP compliance:

yes

Specific details on test material used for the study:

XRD 535 METHYL
Lot #: RN 88-7R
Purity: 98%

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 2.20 to 0.028 µg/mL
- Sample storage conditions before analysis: Deep frozen

Vehicle:

yes

Remarks:

Tween 80

Details on test solutions:

The test substance was suspended in the test medium at a concentration of 10 mg/100 ml (stock suspension) using Tween 80 (0.2 g/100 ml) as detergent. Based on pre-test results, series of sequential dilutions with the test medium were prepared to obtain the final test concentrations of the test article. The highest concentration of Tween 80 was 0.01 %. Along with the test article, control samples with and without Tween 80 were run.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Green algae
- Source: Umweltbundesamt, Berlin (west), West Germany

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

pH:

7.5

Nominal and measured concentrations:

Nominal: 0 (control without tween 80), 0 (control with tween 80), 0.0781, 0.156, 0.3125, 0.625, 1.25, 2.5, 5.0 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks
- Type: Closed
- Material, size, headspace, fill volume: 50 mL Erlenmeyer flasks
- No. of organisms per vessel: 10000 cell per mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- No. of vessels per vehicle control (replicates): 3

GROWTH MEDIUM
- Standard medium used: Yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Photoperiod: Continuous illumination
- Light intensity and quality: 8000 lux

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

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.078 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

1.792 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 1.696-1.897 mg/L

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

3.176 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 2.589-4.037 mg/L

Duration:

96 h

Dose descriptor:

LOEC

Effect conc.:

0.156 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

EC50: 0.82 mg/L (95% CL: 0.81-0.84 mg/L) (growth rate)

Validity criteria fulfilled:

yes

Conclusions:

96 h EC50 (green algae): 1.792 mg/L (growth rate)
72 h EC50 (green algae): 3.176 mg/L (growth rate)
96 h NOEC (green algae): 0.0781 mg/L (growth rate)

Executive summary:

The influence of the test substance on the growth of the green alga was investigated.

The study was performed according to the OECO Guideline 201.

Based on the growth inhibition curve, the NOEC and the LOEC values were found to be 0.0781 mg/L and 0.156 mg/L, respectively. The EC50 values after 72 and 96 hours were 3.176 mg/L and 1.792 mg/L, respectively.

Description of key information

72-hour EC50 (green algae, Desmodesmus subspicatus): 3.176 mg/L; 96 -hour EC50 (green algae): 1.72 mg/L OECD 201; Reliability = 1

96-hour NOEC (Desmodesmus subspicatus): 0.078 mg/L; OECD 201; Reliability = 1

5-day EC50 (freshwater diatom, Navicula pelliculosa): 1.72 mg/L; U.S. EPA-FIFRA Pesticide Assessment Guidelines, Subdivision J, Hazard Evaluation: Non-target Plants Guideline 123-2; Reliability=1

5-day NOEC (freshwater diatom, Navicula pelliculosa): 1.1 mg/L; U.S. EPA-FIFRA Pesticide Assessment Guidelines, Subdivision J, Hazard Evaluation: Non-target Plants Guideline 123-2; Reliability=1

4-day EC50 (Selenastrum capricornutum Printz): >3.87 mg/L; OECD 201, EU Method C.3, U.S. EPA-FIFRA Pesticide Assessment Guidelines, Subdivision J, Hazard Evaluation: Non-target Plants Guideline 123-2; Reliability=1

4-day NOEC (Selenastrum capricornutum Printz): 2.44 mg/L; OECD 201, EU Method C.3, U.S. EPA-FIFRA Pesticide Assessment Guidelines, Subdivision J, Hazard Evaluation: Non-target Plants Guideline 123-2; Reliability=1

Key value for chemical safety assessment

EC50 for freshwater algae:

1.72 mg/L

EC10 or NOEC for freshwater algae:

0.078 mg/L

Additional information

Algae tests were conducted in 3 freshwater species. The EC50 value ranged from 1.72 to 3.87 mg/L and the NOEC values ranged from 0.078 to 2.44 mg/L.