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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:
1998-09-07 to 1998-09-30
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Study conducted in compliance with minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The concentration of solvent was 1 mL/L for all test concentrations instead of the maximum level of 0.1 mL/L. The study report was conclusive and done to a valid guideline.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report date:
1998

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Ethyl (3aR,7R,7aR)-2,2-dimethyl-7-[(methylsulfonyl)oxy]-3a,6,7,7a-tetrahydro-1,3-benzodioxole-5-carboxylate
EC Number:
606-548-2
Cas Number:
204254-84-2
Molecular formula:
C13 H20 O7 S
IUPAC Name:
Ethyl (3aR,7R,7aR)-2,2-dimethyl-7-[(methylsulfonyl)oxy]-3a,6,7,7a-tetrahydro-1,3-benzodioxole-5-carboxylate
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
Yellowish powder
Purity: 97.0%
Expiry date: 09 January 1999

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
The entire volume of each sample (10 mL) was transferred quantitatively into 20 mL volumetric flasks using acetonitrile. The flasks were filled up to the mark with acetonitrile. If necessary, the solutions were further diluted with 50/50 (v/v) acetonitrile / ISO-medium to obtain concentrations
within the calibration range. Samples taken at 0 and 48 hours.

Test solutions

Vehicle:
yes
Details on test solutions:
A pretest was performed to examine the solubility of the test substance in the test medium. A concentration of 100 mg/L could not homogeneously be dissolved or dispersed in test medium. Acetone proved to be a suitable solvent. However, the highest concentration which could be dissolved in
acetone was 100 mg/mL . To include a concentration of 100 mg/L in the test an amount of 1 mL/Lof this stock solution was added to the test medium.
Hence, the concentration of solvent was 1 mL/L for all test concentrations instead of the maximum level of 0.1 mL/L as prescribed by the guidelines.
Stock solutions were prepared separately for each individual test concentration at a factor of 1000 higher than the final test concentrations. All final test solutions were clear without precipitation and ranged from yellow to colourless.
Based on the results of the range-finding test, a range of nominal concentrations from 10 to 180 mg/L increasing by a factor of 1.8.
Controls: Test medium without test substance or other additives (0mg/L), and one control containing test medium with the additive used in the
treatment of the stock solutions (i.e. acetone 1 mL/L).

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
Daphnia maqna (Crustacea, Cladocera) (Straus, 1820).
Young daphnia with an age of < 24 hours were selected for the test.
Start of each batch: With newborn animals, i.e. less than 3 days old, by placing about 250 of them into 10 litres of medium in an ail-glass culture
vessel.
Maximum age of the cultures: 4 weeks
Renewal of the cultures: After 7 days of cultivation half of the medium twice a week.
Temperature o f medium: 18-22 °C constant within +/-1°C
Feeding: Daily, a suspension of fresh water algae.
Medium: M7, as prescribed by Dr. Elendt-Schneider (Elendt, 8 . - P . , 1990: Selenium deficiency in Crustacea. An ultrastructural anoroach to antennal damage in Daphnia maqna' Straus. Protoplasma 154, 25-33).

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h

Test conditions

Test temperature:
21.0 to 21.2°C
pH:
7.9-8.1
Dissolved oxygen:
8.3-8.9
Nominal and measured concentrations:
During the final test samples were taken from 10, 32 and 180 mg/L for analysis. Also samples were taken from the acetone control.
Results: Solvent control - not detected at 0 and 48 hours
Nominal 10 mg/L - analysed 10.2 mg/L (0 hours) and 9.24 mg/L (48 hours)
Nominal 32 mg/L - analysed 34.0 mg/L (0 hours) and 31.6 mg/L (48 hours)
Nominal 180 mg/L - analysed 144 mg/L (0 hours) and 152 mg/L (48 hours)
Details on test conditions:
Test type: Static
Test duration: 48 hours
Test vessels: 100 ml, all-glass
Medium: ISO, prepared in milli-RO water
Number of daphnia: 20 per concentration
Loading: 10 per vessel containing 80 ml medium
Light: 16 hours photoperiod daily
Feeding: No feeding
Aeration: No aeration of the test solutions.
Introduction of daphnia: Within 1/2 hour after preparation of the test solutions.

Sampling: at 0 and 48 hours. 10mL taken from the approximate centre of the test vessel.
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrations
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
69.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% 60.3-86.6 mg/L
Details on results:
The responses recorded in this test allowed for reliable determination of an EC50. The responses recorded after 24 hours of exposure were in
agreement with the results of the range-finding test. The responses at 100 mg/L recorded at the end of the test were higher than expected based on
the results of the range-finding test.
Under the conditions of the present study with the test item, the 24h-EC50 for daphnids exceeded the highest concentration tested, being 180 mg/L.

The 48h-EC50 was 69 mg/L with a 95% confidence interval between 60 and 87 mg/L.
Results with reference substance (positive control):
The reference substance potassium dichromate was tested using daphnia from the same culture as those used with the test item.
Concentrations: 0.10, 0.18, 0.32, 0.56, 1.0 and 1.8 mg/L in ISO-medium. Control: ISO-medium without test substance.
The 24h-EC50 was 0.90 mg/L with 95% fiducial limits of 0.75 - 1.2 mg/L
The 48h-EC50 was 0.52 mg/L with 95% fiducial limits of 0.46 - 0.65 mg/L.
The actual responses in this reference test were within the ranges of the expected responses at the different concentrations. Hence, the sensitivity
of this batch of D. magna was in agreement with the historical data collected.
Reported statistics and error estimates:
The EC50-value was calculated at 48 hours of exposure from the probits of the percentages of affected daphnia and the logarithms of the corresponding test substance concentrations using the maximum likelihood estimation method (Finney, D.J., 1971: Probit analysis, Cambridge University Press, Cambridge, U.K., 3rd edition).

Any other information on results incl. tables

No daphnids became immobilized or trapped at the surface of the water in either the blank- or the solvent-controls. Hence, the acetone concentration of 1 ml/L had no effect on the condition of the daphnids exposed in the treated solutions. The analytical program showed that the actual test concentrations were stable during the exposure period and could be maintained at 80 % of the initial concentration. Further, all test conditions remained within the ranges prescribed by the protocol.

Table of acute immobilization of daphnia after 24 or 48 hours:

 Test item concentration (mg/L)  Vessel code  Number exposed  Response: number immobile at 24 hours   Response: number immobile at 48 hours
 Blank - control  A  10  0  0
   B  10  0  0
 Acetone-control  A  10  0  0
   B  10  0  0
 10  A  10  0  0
   B  10  0  0
 18  A  10  0  0
   B  10  0  0
 32  A  10  0  0
   B  10  0  0
 56  A  10  0  1
   B  10  0  0
 100  A  10  0  10
   B  10  0  9
 180  A  10  0  10
   B  10  1  10

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the conditions of the present study with the test item, the 24h-EC50 for daphnids exceeded the highest concentration tested, being 180 mg/L.

The 48h-EC50 was 69 mg/L with a 95% confidence interval between 60 and 87 mg/L.
Executive summary:

After a range-finding test, a final test was performed with Daphnia exposed for a maximum of 48 hours to a range of nominal concentrations from 10 to 180 mg/L. The test was performed in duplicate with 10 daphnia per vessel. Acetone was used as a presolvent in the stock solutions. Due to the limited solubility of the test substance in acetone, the concentration of this solvent in the test solutions was 1 mL/L instead of 0.1 mL/L as prescribed by the guidelines. Samples for analysis were taken at the start and the end of the final test.

Analysis of the samples taken during the final test showed that the measured concentrations were in agreement with nominal. No daphnia became immobilised or trapped at the surface in the solvent-controls. Hence, the acetone concentration of 1 mL/L had no effect on the condition of the daphnids exposed in the treated solutions.

Under the conditions of the present study with the test item, the 24h-EC50 for daphnids exceeded the highest concentration tested, being 180 mg/L. The 48h-EC50 was 69 mg/L with a 95% confidence interval between 60 and 87 mg/L.