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

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 Mar- 16 Oct 1991

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study

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 203 (Fish, Acute Toxicity Test)

Version / remarks:

Adopted in 1981, updated in 1984

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

EEC Directive 67/548 Annex V C.1 (84/449/EEC). Adopted in 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
- Stability under test conditions: ensured by daily renewal of test media and verified by chemical analysis
- Storage condition of test material: in darkness at 4°C

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Duplicate samples (each comprising 100.0 mL test medla plus 1.0 ml 50% v/v orthophosphoric acid (aqueous) in 100 ml glass bottles) were
received from the Unit of Fish Toxicology between 22 and 26 March 1991. One of each sample pair was stored at -20 °C. The retained sample was shaken and a sub-sample transferred by bulb pipette (5.0 mL) to a volumetric flask (10.0 mL). The sample was made to volume with acetonitrile and shaken. An aliquot was passed through a 0.45 micron membrane filter and retained for analysis.
- Samples were collected from control and test concentrations at 0 and 72 hours (fresh media) and at 24 and 96 hours (expired media)

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):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: Westacre Trout Farm, Swaffham, United Kingdom
- Length at study initiation (mean, SD): 3.8 cm, 0.2 cm
- Weight at study initiation (mean, SD): 0.67 g, 0.14 g
- Feeding during test: no

ACCLIMATION
- Acclimation period: the fish stock was held since 26 February 1991 and acclimatised to test conditions since 4-22 March 1991
- Acclimation conditions (same as test or not): yes
- Type of food: commercial trout pellets
- Feeding frequency: daily, discontinued 24 h prior to test
- Health during acclimation (any mortality observed): no mortalities were observed during the acclimation period

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test conditions

Hardness:

~ 350 mg/L as CaCO3

Test temperature:

14 ± 1 °C

pH:

7.9-8.0

Dissolved oxygen:

≥ 10.2 mgO2/L

Nominal and measured concentrations:

Nominal: control, 1.0, 1.8, 3.2, 5.6 and 10 mg/L
Measured: control, 0.81, 1.5, 2.5, 4.6 and 7.8 mg/L
The test substance concentration ranged from 87-96% of nominal concentrations for fresh media and 67-87% for expired media

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass aquaria containing 20 L of test medium
- Aeration: yes, via narrow bore glass tubes
- Renewal rate of test solution: daily
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): 1
- Biomass loading rate: 0.34 g bw/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: laboratory tap water, dechlorinated by the addition of sodium thiosulphate

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

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality and behaviour at 3, 6, 24, 48, 72 and 96 hours

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

3.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CI: 2.5-4.6 mg/L

Effect concentrations 2

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

3.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CI: 2.6-3.8 mg/L

Effect concentrations 3

Duration:

72 h

Dose descriptor:

LC50

Effect conc.:

2 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CI: 1.5-2.5 mg/L

Effect concentrations 4

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

1.6 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CI: 1.4-1.8 mg/L

Details on results:

- Behavioural abnormalities: Loss of equilibrium, increased pigmentation and lethargic state were observed at concentrations from 1.8 mg/L and above
- Mortality of control: no mortalities were reported in either control or solvent control

Any other information on results incl. tables

Sublethal observations / clinical signs:

Table 1. Cumulative mortality data for rainbow trout exposed for 96 hours to fluroxypyr methyl ester

Test concentration (mg/L)	Cumulative mortality (initial population: 10)
	3 h	6 h	24 h	48 h	72 h	96 h
Control	0	0	0	0	0	0
Solvent control	0	0	0	0	0	0
1.0	0	0	0	0	0	0
1.8	0	0	0	0	0	2
3.2	0	0	0	3	10	10
5.6	0	0	10	10	10	10
10.0	0	0	10	10	10	10

Applicant's summary and conclusion

Validity criteria fulfilled:

yes