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

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

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 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

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: 0.085 µg/mL XRD-535 acid and 0.055 µg/mL test substance
- Sample storage conditions before analysis: Deep frozen

Vehicle:

yes

Remarks:

Tween 80 (polyoxyethylene sorbitan monooleate)

Details on test solutions:

The test substance was suspended in the test medium by sonicating for 30 minutes at a concentration of 100 mg/100 ml (stock suspension) using Tween 80 (0.10 g/100 ml) as solubilizing agent. Thereafter, 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 substance, control samples with and without Tween 80 were tested.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Strain/clone: Daphnia magna
- Age at study initiation: Less than 24 hrs
- Source: Laboratories of RCC
- Feeding during test : No feeding

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20 ± 2°C

pH:

Initial: 8.3
Final: 8.2

Dissolved oxygen:

Initial: 8.5 mg/L
Final: 8.4 mg/L

Nominal and measured concentrations:

Nominal: 0 (control with tween 80), 0 (control without tween 80), 0.78, 1.56, 3.13, 6.25, 12.5, 25, 50, 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Beaker
- Material, size, headspace, fill volume: 50 mL beakers containing 20 mL test medium
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 2

TEST MEDIUM
- CaCl2.2H2O: 294 mg/L
- MgSO4.7H2O: 123 mg/L
- NaHCO3: 65 mg/L
- KCl: 5.8 mg/L

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

6.12 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Immobility

Remarks on result:

other: 95% CL: 4.10-12.41 mg/L

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

30.66 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Immobility

Remarks on result:

other: 95% CL: 13.26-78.38 mg/L

Details on results:

- Mortality of control: No mortality was observed within 48 hours for the untreated control. The mortality of Tween 80-treated samples was 0% after 24 and 48 hours of exposure.

Results with reference substance (positive control):

48 h EC50: 1.3 mg/L (1.1-1.8 mg/L)
24 h EC50: 1.7 mg/L (1.4-2.0 mg/L)

Validity criteria fulfilled:

yes

Conclusions:

48 h EC50 (D. magna): 6.12 mg/L
24 h EC50 (D. magna): 30.66 mg/L

Executive summary:

The test substance was tested for its acute toxicity to Daphnia magna under static conditions for 48 hours. The tests were performed according to OECD guideline 202 and EU method C.2. Concentrations tested were 0 (control), 0.78, 1.56, 3.13, 6.25, 12.5, 25, 50 and 100 mg/L. The low, medium and high concentrations were sampled for acid and ester content. Analysis showed partial hydrolysis of the ester to the corresponding acid.

The EC0 after 24 and 48 hours was determined to be 1.95 and 1.09 mg/L, respectively. The 24 and 48 hours EC50 of the test substance based on initial nominal concentrations were calculated to be 30.66 and 6.12 mg/L, respectively. It is concluded that the test substance showed a slight toxicity to daphnids when exposed for 24 hours. After 48 hours, the toxicity increased to the moderate level.

The immobilization rate of the control animals was 0% after 48 hours. The tests were validated by testing potassium dichromate. The EC50 values determined for potassium dichromate after 24 and 48 hours were 1.7 and 1.3 mg/L, respectively.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

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:

EPA OPP 72-3 (Estuarine/Marine Fish, Mollusk, or Shrimp Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Haloxyfop-methyl
Lot #: AGR 229637
Purity: 99.5%

Analytical monitoring:

yes

Vehicle:

yes

Remarks:

dimethyl formamide (DMF)

Test organisms (species):

other: Crassostrea virginica (Eastern oyster)

Test type:

flow-through

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

23.6-24.4°C

pH:

7.8-8.0

Dissolved oxygen:

6.3 mg/L (91% saturation) and 7.1 mg/L (100% saturation)

Salinity:

31-32%

Nominal and measured concentrations:

Nominal: 0 (dilution water control), 0 (solvent control), 0.065, 0.108, 0.180, 0.300, 0.500 mg/L

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

0.32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: new shell growth

Remarks on result:

other: 95% CL: 0.29-0.35 mg/L

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.098 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: new shell growth

Description of key information

48-hour EC50 (Daphnia magna): 6.12 mg/L; OECD 202, EU Method C.2; Reliability = 1

96-hour EC50 (Crassostrea virginica): 0.32 mg/L; EPA 72 -3; Reliability = 1

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

6.12 mg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

0.32 mg/L

Additional information

Acute aquatic invertebrate tests were conducted in one freshwater species and one marine species. The 48-h EC50 value in fresh water species, Daphnia magna was 6.12 mg/L and 96 -h EC50 in marine water species, Crassostrea virginica was 0.32 mg/L.