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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:

30 April 2003 to 31 October 2003

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:

July 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

EC Comission Directive 1999/11/EC of 8 March 1999 (Official Journal No L 77/8)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Test concentrations were verified by chemical analysis. Triplicate 100 ml samples were taken from the control and each test concentration at 0 and 72 hours (fresh media), 24 and 96 hours (expired media) for analysis.

Vehicle:

no

Details on test solutions:

Samples of the test substance weighing 500 mg were dispersed in separate 5.0 litre flasks of test medium and ultrasonicated for one hour with intermittent vigorous shaking. These were then pooled to produce a stock dispersion of 100 mg/l. Serial dilutions of this stock dispersion were prepared with test medium to give the remaining nominal test concentrations (in descending order of concentration) of 46, 22, 10, 4.6 and 2.2 mg/l.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: Westacre Trout Farm, Norfolk

- Length at study initiation (mean and SD): 5.1 ± 0.52 cm
- Weight at study initiation (mean and SD): 2.11 ± 0.51 g

HOLDING / ACCLIMATION
- Acclimation period: at least 14 days after delivery
- Acclimation conditions (same as test or not): same
- Type and amount of food during acclimation: 2 % of their body weight daily with commercial fry pellet
- Health during acclimation (any mortality observed): no medication, mortalities 0 %

FEEDING DURING TEST
No feeding from 24 hours prior to the test and during the total test period

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

149 -168 mg CaCO3/l

Test temperature:

14 - 15 °C

pH:

7.2 - 7.4

Dissolved oxygen:

8.9 – 9.6 mg O2/l

Nominal and measured concentrations:

Nominal concentrations: 2.2, 4.6, 10, 22, 46 and 100 mg/l
Mean measured concentrations (unfiltered): 2.1, 4.4, 9.3, 21, 45 and 94 mg/l
Mean measured concentrations (filtered): 1.7, 4.0, 8.4, 19, 40 and 78 mg/l
The unfiltered samples ranged from 84.3 – 102 % of nominal (fresh medium; 0 and 72 hours) and from 89.2 – 101 % of nominal (expired medium; 24 and 96 hours). The filtered samples ranged from 77.0 – 88.4 % of nominal (fresh medium; 0 and 72 hours) and from 74.4 – 91.3 % of nominal (expired medium; 24 and 96 hours).

All results are expressed in terms of mean measured concentrations of unfiltered samples. For details on the chemical analysis (measured concentrations of T-71) see Appendix 3 “T-71 – results acute toxicity to fish.pdf”).

Details on test conditions:

TEST SYSTEM
- Test vessel: vessels (25 x 46 x 25 cm), containing 20 liters of test medium
- Type (delete if not applicable): open
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Supplementary aeration was provided in this study, through narrow bore glass tubes.
- Biomass loading rate: 0.74 g bodyweight/L (static volume)

TEST MEDIUM / WATER PARAMETERS
Dilution water: The water used for the study was laboratory tap water filtered, dechlorinated and softened by passage through a Vivendi® water purification system. Total chlorine levels ranged from 0.00 to 0.03 mg/l and free chlorine from 0.00 to 0.02 mg/l throughout the seven days of the acclimatisation period and during the exposure period. The water hardness, measured daily during the same period.

Medium renewal: Fish were exposed to the test or control conditions for a period of 96 hours with daily batchwise renewal of the test medium to ensure the maintenance of satisfactory environmental conditions and near nominal exposure levels.

OTHER TEST CONDITIONS : Adjustment of pH: no; Photoperiod: 16 hour photoperiod daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Mortality and sub-lethal effects were recorded at 15 minutes 2, 4, 24, 48, 72 and 96 hours following the start of exposure. In addition, every afternoon from day 0 to observe for any dead or severely distressed fish. The environmental parameters (pH, mgO2/l, T°C) were recorded at 0, 24, 48, 72, 96 hours.

TEST CONCENTRATIONS
-Spacing factor for test concentrations: 2.2
-Range finding study: test concentrations ranging from 1.0 to 100 mg/l; results indicated that the LC50 was likely to lie between 10 and 100 mg/l.

CRITERIA OF EFFECT: The criteria of death employed in this study were (i) absence of respiratory movement and (ii) absence of response to physical stimulation of the caudal peduncle.

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

30.7 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% confidence limit (21 - 45 mg/l)

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

21 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

There was a clear treatment related effect on the survival of the fish, with no mortality at 2.1, 4.4, 9.3 and 21 mg/l, the four lowest concentrations, and 100% mortality at the two highest test concentrations of 45 and 94 mg/l. There was no mortality in the control group.
For details see attachment "T-71 - results acute toxicity to fish.pdf".

Reported statistics and error estimates:

LC50 values were calculated using a logistic model (Ashton, 1972) for which 95% confidence limits were estimated by the likelihood ratio method (Williams, 1986).

Sublethal observations / clinical signs:

After 2 and 4 hours exposure, remaining fish in 45 mg/l were observed to exhibit coughing.

Validity criteria fulfilled:

yes

Remarks:

no mortality of control animals; concentration of dissolved oxygen in all test vessels >60 % of the air saturation; test conditions were maintained constant throughout the test

Description of key information

LC₅₀ (96h) of 30.7 mg/l (95% confidence limits: 21 - 45 mg/l) for Oncorhynchus mykiss (EU Method C.1, OECD guideline 203)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

30.7 mg/L