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Ecotoxicological information

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:
27th February 2003 to 8th May 2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Proprietary study conducted according to guidelines and GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report Date:
2003

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
and US EPA OPPTS 850.1010
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
E-Caprolactone, clear colourless liquid. Purity: 99.95%. Batch no: U05175. Stored at room temperature.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
No relevant.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Aliquots of the samples were directly used for GC-analysis at test initiation (time 0) and test termination (time 48). Nominal concentrations analysed were 0, 62.5, 125, 250, 500 and 1000 mg/l.

Test solutions

Vehicle:
no
Details on test solutions:
e-Caprolactone in solution with M4-medium: synthetic fresh water (used for culture and test purposes. M4 medium is aerated for approximately 24 hours with oxygen until saturation is reached. The stock solution and dilution was prepared by stirring the test substance in the M4 medium for approximately 10 minutes at 20±2oC. The stock solution was clear and colourless, with a nominal concentration of 1000mg/l. The stock solution was diluted with M4 medium.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
A clone of Daphnia magna STRAUS 1820 was used. Animals were aged 2-24h at the start of the test (starting with the 3rd generation of parent animals). Stock animals were 2-4 weeks old. They were kept under artificial light, type warm white (OSRAM L58 W31) on a day:night cycle of 16:8h. The animals were not fed during the test.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
No post-exposure observation period.

Test conditions

Hardness:
M4 medium: 2.20-3.20 mmol/l
Test temperature:
19.6-20.1oC
pH:
7.8-8.1
Dissolved oxygen:
7.1-9.7mg/l (M4 medium aerated for 24 hours with oxygen until saturation is reached).
Salinity:
Not relevant; freshwater test.
Nominal and measured concentrations:
Nominal: 0, 62.5, 125, 250, 500 and 1000 mg/l. Measured test initiation (mean two samples): 0, 66.5, 126.1, 252, 481 and 973mg/l. Measured test termination (mean two samples): 0, 59.4, 124.6, 249, 499 and 980mg/l.
Details on test conditions:
Test vessels were glass test tubes with flat bottoms (nominal volume 20ml). Test volume: 10ml. 5 animals per vessel; 0.5 animals/ml. 4 replicates per concentration; 20 animals per concentration. There 4 replicates/control, and 1 replicate for measurement of pH and oxygen. 1 parallel per test concentration and control without animals for measurement of pH and oxygen at start of experiment, this was thrown away after measurement. Daphnia were kept under artificial light, type warm white (OSRAM L58 W31) on a day:night cycle of 16:8h.
Visual observations were made at 0, 24 and 48h to determine swimming ability; if Daphnia were unable to swim within 15 seconds, even after gentle agitation of the test vessel, they were considered to be immobile.
Test-substance was used in solution with M4 medium. M4 medium parameters: pH = 8.2; conductivity = 596µS/cm; total hardness = 2.42mmol/l; Ks up to pH 4.3 = 0.87mmol/l.
An initial non-GLP range finding study was conducted to determine concentrations for the main test.
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
259 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC0
Effect conc.:
125 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
204 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 172-240mg/l
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
500 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
No precipitation of test material was observed. Immobilisation in the control did not exceed 10%.
Results with reference substance (positive control):
The EC50(24h) of the control substance potassium dichromate (non-GLP) was 1.37mg/l (project number 02/0106/50/13).
Reported statistics and error estimates:
The probit method was used for calculation of the EC50, with 95% confidence limits.

Any other information on results incl. tables

Validity criteria met: in the control the immbolisation observed was ≤10%. In the control no Daphnids were captured in a surface film. The O2 concentration was >3mg/l in all tested replicates.

As the analytical results were found be within +/- 80% on the nominal exposure concentrations the results are based on nominal exposure concentrations.

The number of immobile Daphnia measured at each timepoint is presented below (20 Daphnia exposed in each concentration)

Nominal conc. (mg/L)

Number of immobile Daphnia

% inhibition

24 hours

48hours

24 hours

48hours

Control

0

0

0

0

62.5

0

0

0

0

125

0

1

0

5

250

7

15

35

75

500

20

20

100

100

1000

20

20

100

100

 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The toxicity of e-Caprolactone to the water flea, Daphnia magna, was determined in the 48 hour acute immobilisation test conducted according to OECD 202. The daphnids were exposed to concentrations of e-Caprolactone between 6.25 and 1000mg/l. The 48 hour EC50 was 204mg/l (with 95% confidence limits: 172 -240mg/l). Validity criteria were fulfilled.
Executive summary:

The toxicity of e-Caprolactone to the water flea, Daphnia magna, was determined in the 48 hour acute immobilisation test conducted according to OECD 202. The daphnids were exposed to concentrations of e-Caprolactone between 6.25 and 1000mg/l. The 48 hour EC50 was 204mg/l (with 95% confidence limits: 172 -240mg/l).