Oxazolidine, 3-butyl-2-(1-ethylpentyl)-

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:

from 2005-06-06 to 2005-06-20

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:

adopted 17 July 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

adopted 31 July 1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Sampling method: The concentration and stability of the test material in the test preparations were verified by chemical analysis at 0 (fresh media), 24, 48, 72 (old and fresh media) and 96 hours (old media). A Strata X solid phase extraction (SPE) cartridge was sequentially pre-conditioned with acetonitrile and water. A volume of test sample was eluted through the cartridge. The test material was eluted from the cartridge with acetonitrile and prepared for subsequent GC-FID analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
Formulation: For the purpose of the definitive test the test material was dissolved directly in water with the aid of prolonged stirring. An amount of test material (2.25 g) was dispersed in 22.5 litres of dechlorinated tap water and stirred using a propeller stirrer set at approximately 1500 rpm at approximately 14 °C to 16 °C for 24 hours to give the 100 mg/L test concentration. The 100 mg/L test concentration was prepared in four replicates to give sufficient volume for the dilutions. Aliquots (4.0, 7.2, 12.8, and 22.4 litres) of the 100 mg/L test concentration were separately dispersed in dechlorinated tap water and the volume adjusted to 40 litres to give the remaining test concentrations of 10, 18, 32 and 56 mg/L, respectively.
Each of the prepared test concentrations was mixed thoroughly to ensure homogeneity.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Juvenile rainbow trout (Oncorhynchus mykiss)
- Source: Brow Well Fisheries Limited, Hebden, near Skipton, Yorkshire, UK
- Length at study end: mean standard length of 5.8 cm (SD = 0.2)
- Weight at study end: a mean weight of 2.91 g (SD = 0.38)
- Food type: commercial trout pellets which was discontinued approximately 24 hours prior to the start of the definitive test

ACCLIMATISATION
- Acclimation period: 15 June 2005 to 27 June 2005
- Acclimation conditions: 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods. Water temperature was controlled at approximately 14 °C with a dissolved oxygen content of greater than or equal to 9.8 mg O2/L.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

ca. 100 mg/L as CaCO3.

Test temperature:

13.6 - 15.3 °C

pH:

7.4 to 8.1 in the control group
7.5 to 8.2 in the 10 mg/L test group
7.6 to 8.2 in the 18 mg/L test group
8.0 to 8.2 in the 32 mg/L test group
8.4 to 8.6 in the 56 mg/L test group
up to 9.1 in the 100 mg/L test group

Dissolved oxygen:

83 to 101 % of ASV in the control in the control group
83 to 99 % of ASV in the control in the 10 mg/L test group
84 to 100 % of ASV in the control in the 32 mg/L test group
90 to 101 % of ASV in the control in the 56 mg/L test group
90 to 101 % of ASV in the control in the 100 mg/L test group
ASV = Air Saturation Value

Salinity:

not applicable

Nominal and measured concentrations:

Due to the rapid hydrolysis of the test item, steady measured concetrations of the test item was not achievable. The hydrolysis products could not be detected by the analytical method due to possible but unconfirmed adsorption to surfaces.

Details on test conditions:

TEST SYSTEM
- Test vessel: 40 litre glass exposure vessel
- No. of organisms per vessel: 7 animals per test vessel

TEST MEDIUM / WATER PARAMETERS
- Total organic carbon: average of 1.675 mg/L
- Pesticides: below detection limit
- Chlorine: average of < 0.135 mgL

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
NOEC: No Observed Effect Concentration: the highest test concentration at which no significant effect on the test animals is observed
LC 50: The calculated concentration of the test item which kills 50 % of the test fish.

TEST CONCENTRATIONS
In the initail range-finding test fish were exposed to a series of nominal test concentrations of 1.0, 10 and 100 mg/L.
Based on the results of the range-finding test the following test concentrations were assigned to the definitive test: 10, 18, 32, 56 and 100 mg/L.

Reference substance (positive control):

no

Duration:

3 h

Dose descriptor:

LC50

Effect conc.:

39 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% confidence limits 34 - 45 mg/L

Duration:

6 h

Dose descriptor:

LC50

Effect conc.:

39 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% confidence limits 34 -45 mg/L

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

39 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% confidence limits 34 -45 mg/L

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

24 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% confidence limits 18 -32 mg/L

Duration:

72 h

Dose descriptor:

LC50

Effect conc.:

22 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% confidence limits 19 -26 mg/L

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

20 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% confidence limirs 17 - 25 mg/L

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

<= 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: zero mortality and absence of sub-lethal effects

Details on results:

Due to the rapid hydrolysis of the test item, steady measured concentrations of the test item were not achivable. The hydrolysis products could not be detected by the analytical method due to possible but unconfirmed adsorption to surfaces.
Analysis of the mortality data by the trimmed Spearman-Karber method.

Sub-lethal effects
At 18 mg/L:
Increased pigmentation: 3/7 (48 h), 2/6 (72 h), 2/5 (96 h)
Swimming at the bottom with increased pigmentation: 4/7 (48 h), 3/6 (72 h), 3/5 (96 h)
Loss of equilibrium with increased pigmentation: 1/6 (72 h)
One fish was observed moribund at 75 h

At 32 mg/L:
Swimming at the bottom: 6/6 (3 h), 6/6 (24 h)
Swimming at the bottom with increased pigmentation: 6/6 (6 h)
All fish dead (48 h)

At 56 mg/L: All fish dead (3 h)
At 100 mg/L: All fish dead (3 h)

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test material to the freshwater fish rainbow trout (Oncorhynchus mykiss) has been investigated and gave a 96-hour LC50 value of 20 mg/L with 95 % confidence limits of 17 - 25 mg/L. The No Observed Effect Concentration was 10 mg/L.

Executive summary:

Acute toxicity of the test item was assessed with the rainbow trout (Oncorhynchus mykiss) in accordance to the relevant OECD guideline No 203 and EU method C.1. Following a preliminary range-finding test, fish were exposed, in groups of seven, to aqueous solutions of the parent test material over a concentration range of 10, 18, 32, 56 and 100 mg/L for a period of 96 hours at a temperature of 13.6 to 15.3 °C under semi-static test conditions. The number of mortalities and any sub-lethal effects of exposure in each test and control vessel were determined 3 and 6 hours after the start of exposure and then daily throughout the test until termination after 96 hours.

Due to the rapid hydrolysis of the test item, steady measured concentrations of the test item were not achievable. The hydrolysis products could not be detected by the analytical method due to possible but unconfirmed adsorption to surfaces.

The LC50 values based on nominal test concentrations were the following: 3 h LC50 = 39 mg/mL; 6 h LC50 = 39 mg/mL; 24 h LC50 = 39 mg/mL; 48 h LC50 = 24 mg/mL; 72 h LC50 = 22 mg/mL; 96 h LC50 = 20 mg/mL.

The No Observed Effect Concentration (NOEC) was 10 mg/L.

Sub-lethal effects of exposure were observed at test concentrations of 18, 32 and 56 mg/L. These responses were swimming at the bottom, increased pigmentation, swimming at the bottom with increased pigmentation, loss of equilibrium with increased pigmentation and the presence of moribund fish. After 1.5 hours of exposure one out of seven fish at 32 mg/L and seven out of seven fish at 56 and 100 mg/L were observed to be moribund. After 29 hours exposure one out of six fish were observed dead and three out of six fish moribund at 32 mg/L. After 30 hours exposure the remaining fish were observed moribund at 32 mg/L. After 75 hours of exposure one out of six fish was observed moribund at 18 mg/L.

Description of key information

The acute toxicity of the test material to the freshwater fish rainbow trout (Oncorhynchus mykiss) has been investigated and gave a 96-hour LC50 value of 20 mg/L with 95 % confidence limits of 17 - 25 mg/L. The No Observed Effect Concentration was 10 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

20 mg/L

Additional information

Acute toxicity of the test item was assessed with the rainbow trout (Oncorhynchus mykiss) in accordance to the relevant OECD guideline No 203 and EU method C.1. Following a preliminary range-finding test, fish were exposed, in groups of seven, to aqueous solutions of the parent test material over a concentration range of 10, 18, 32, 56 and 100 mg/L for a period of 96 hours at a temperature of 13.6 to 15.3 °C under semi-static test conditions. The number of mortalities and any sub-lethal effects of exposure in each test and control vessel were determined 3 and 6 hours after the start of exposure and then daily throughout the test until termination after 96 hours.

The LC50 values based on nominal test concentrations (due to the rapid hydrolysis of the parent compound) were the following:

3 h LC50 = 39 mg/mL; 6 h LC50 = 39 mg/mL; 24 h LC50 = 39 mg/mL; 48 h LC50 = 24 mg/mL; 72 h LC50 = 22 mg/mL; 96 h LC50 = 20 mg/mL.

The No Observed Effect Concentration (NOEC) was 10 mg/L.