Methyl O-(4-amino-3,5-dichloro-6-fluoropyridin-2-yloxy)acetate

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:

26 Mar - 28 Mar 1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study with acceptable restrictions (test concentrations reached 20-24% of nominal at 48 hours)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

Adopted in 1984

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

EEC Directive 67/548 Annex V, C2 (84/449/EEC), 1984

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Methyl O-(4-amino-3,5-dichloro-6-fluoropyridin-2-yloxy)acetate

EC Number:

407-550-4

EC Name:

Methyl O-(4-amino-3,5-dichloro-6-fluoropyridin-2-yloxy)acetate

Cas Number:

69184-17-4

Molecular formula:

Hill formula: C8 H7 Cl2 F N2 O3 CAS formula: C8 H7 Cl2 F N2 O3

IUPAC Name:

methyl 2-[(4-amino-3,5-dichloro-6-fluoropyridin-2-yl)oxy]acetate

Details on test material:

- Name of test material (as cited in study report): Fluroxypyr methyl ester
- Physical state: solid, grey powder
- Analytical purity: 90.8%
- Lot/batch No.: C-3B
- Expiration date of the lot/batch: August 1992
- Storage condition of test material: in darkness at 4°C

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Duplicate samples (each comprising 50.0 mL test medla plus 1.0 ml 5N sulphuric acid (aqueous) in 100 ml glass bottles) were received from the Unit of Fish Toxicology between 26 and 28 March 1991. One of each sample pair was stored at -20 °C. The retained sample was shaken and the contents transferred to a separating funnel. The bottle was rinsed with dichloromethane (50 mL) and the washings also transferred to the separating funnel. After extraction (1 minute shake) the lower organic layer was drained into a round-bottomed flask and the aqueous layer re-extracted with dichloromethane (50 mL). The organic phases were combined and the solvent evaporated just to dryness (at 40 °C). Any remaining solvent was removed under nitrogen and the extracts dissolved in mobile phase for analysis.
- Samples were collected from control and test concentrations (replicates pooled) at 0 hours, and from the top five concentrations at 48 hours.

Test solutions

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The preliminary solution was created by adding the test substance and 1% Tween 80-acetone
- Controls: blank and vehicle control
- Chemical name of vehicle: acetone

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Strain: Straus
- Source: laboratory culture originating from a strain supplied by IRChA, France
- Age at study initiation: < 24 hours

ACCLIMATION
- Acclimation conditions: daphnids were kept at 20 ± 2 °C in glass vessels containing 2 L of dechlorinated and aged tap water. Gravid adults were isolated 24 hours prior to initiation of the test in which the young daphnids produced overnight were used.
- Type of food: fry fish food
- Feeding frequency: daily

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Test conditions

Hardness:

~ 350 mgCaCO3/L

Test temperature:

21 ± 1 °C

pH:

7.9

Dissolved oxygen:

8.6-8.9 mgO2/L

Nominal and measured concentrations:

Nominal: control, 0.1, 0.18, 0.32, 0.56, 1.0, 1.8, 3.2, 5.6 and 10 mg/L
Relevant measured: control, 0.56, 1.0, 2.0, 3.2 and 5.1 mg/L
Test concentrations ranged from 80 - 103 % of nominal at 0 hours to 20 - 24 % of nominal at 48 hours (average 67 %)

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass jars containing 200 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
- Biomass loading rate: 20 mL test solution per organism

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dechlorinated (with sodium thiosulphate) and aged laboratory tap water

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light, 8 hours darkness

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobilisation at 24 and 48 hours

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 5.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 5.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- No immobilisation was reported in either test concentration or control groups

Applicant's summary and conclusion

Validity criteria fulfilled:

yes