pymetrozine (ISO); (E)-4,5-dihydro-6-methyl-4-(3-pyridylmethyleneamino)-1,2,4-triazin-3(2H)-one

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 Aug 1992 to 26 Nov 1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1984

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Composite samples of each test concentration were drawn by mixing identical volumes of the test solutions taken from the approximate center of the test vessels. They were taken immediately before the exposure and after 96 hours exposure and kept at - 18°C to - 22°C until analysis.

Vehicle:

no

Details on test solutions:

- Stock solution: 10.001 g test substance were mixed and made up to 5000 mL with water.
Calculated amounts of the stock solution to produce the desired test concentrations were given into the water and were homogeneously distributed. The fishes were then transfered into the aquaria. The test substance was homogeneously distributed in the test vessel at all test times and test concentrations.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Supplier: P. Hohler / CH-4314 Zeiningen
- Length at study initiation: 55 mm (50 - 58 mm) based on 10 fishes
- Weight at study initiation: 1.40 g (1.10 - 1.65 g) based on 10 fishes

ACCLIMATION
- Acclimation period: 32 days
- Adaptation: No food 24 hours prior to exposure

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

161 mg as CaCO3/L

Test temperature:

14 ± 1 °C

pH:

- pH at test start: 7.6 - 7.7
- pH at test end: 8.2 - 8.3

Dissolved oxygen:

94 - 104 % O2

Salinity:

Not reported

Conductivity:

Not reported

Nominal and measured concentrations:

- Nominal concentrations: 0 (control), 10, 18, 32, 58 and 100 mg/L
- Mean measured concentrations at t=0h: <0.6 (control, LOD), 9.2, 16.3, 29.8, 52.8 and 101.0 mg/L
- Mean measured concentrations at t=96h: <0.6 (control, LOD), 8.5, 16.3, 29.8, 54.7 and 99.8 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass aquaria of 20 liters filled with 15 liters (36x22x25 cm).
- Aeration: Gentle aeration during exposure.
- No. of organisms per vessel: 10
- No. of vessels per concentration: 2
- No. of vessels per control (replicates): 2
- Biomass loading rate: 0.46 g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dechlorinated tap water (carbon filter)

WATER QUALITY MEASUREMENTS
The oxygen content, pH and temperature were measured at 0, 24, 48, 72 and 96 hours.

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light / 8 hours dark
- Light quality: Fluorescent light

EFFECT PARAMETERS MEASURED: mortality and sub-lethal effects
Mortalities were recorded after 24, 48, 72 and 96 hours exposure. The fishes were examined daily for sub-lethal effects (swimming behaviour, loss of equilibrium, respiratory functioning, exophtalmus and pigmentation).

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

No mortality or sub-lethal effects were observed in the control group and any of the test substance treatments after 96 hours exposure.

Validity criteria fulfilled:

yes

Remarks:

see 'Any other information on materials and methods incl. tables'

Conclusions:

The acute toxicity of the test substance to rainbow trout has been investigated by exposing fish under static conditions to concentrations between 0 and 100 mg/L of the test substance followed by a 96 hours observation period. Up to 100 mg/L no mortalities occurred and no other symptoms were observed. Measured initial and final concentrations were between 91 % and 101 % of the nominal values.

Executive summary:

The short-term toxicity to freshwater fish was determined in a study according to OECD TG 203 and in compliance with GLP criteria. In this study, groups of 10 rainbow trout (Oncorhynchus mykiss) were exposed to nominal concentrations of 0 (control), 10, 18, 32, 58 and 100 mg/L for 96 hours under static conditions. Water samples of the nominal test concentrations were taken at t = 0h and 96h for test substance analysis. Throughout the study, the measured concentrations remained within ±20% of the nominal concentrations; therefore, effect concentrations are expressed as nominal. Incidences of mortality and sub-lethal effects were recorded daily. The validation criteria were met. Up to 100 mg/L no mortalities occurred and no other symptoms were observed. Based on these findings, the 96-h LC50 value was determined to be >100 mg/L.

Description of key information

All available data was assessed and the studies representing the worst-case effects were included as key studies. Other studies are included as supporting information. The key studies are considered to be worst-case and were selected for the CSA.

- The 96 -h LC50 value is > 100 mg/L in freshwater fish (Oncorhynchus mykiss), OECD 203, Grade 1993

- No quantitative acute effect value can be determined as no ≥ 50% mortality was reached.

Additional information

Table: Overview of available data on the short-term toxicity to fish

Species	Guideline / GLP	Endpoint	Effect value	Comment	Reference
Oncorhynchus mykiss(freshwater)	OECD 203 / GLP	96-h LC50	>100 mg mg/L	Static regime. Measured concentrations remained within 20% of nominal. No mortalities occurred and no other symptoms were observed in all treatments	Grade, 1993