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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:
21 March 2005 to 23 March 2005
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study was conducted in 2002 according to OECD Method # 202 and in accordance with GLP. The study material is well characterized

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report Date:
2005

Materials and methods

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

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
extremely light tan coloured powder; stored at room temperature in the dark; received at testing laboratory on 15 February 2005 .
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
potassium dichromate. Test series (0.32,0.56, 1.0, 1.8 and 3.2 mg/L) were made from 100 mg/L and 10 mg/L stock solutions in reconstituted water.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Water samples were taken from the control (replicates R1 -R2 pooled) and the 100 mg/L test group (replicates R1-R2 and R3 -R4 pooled) at 0 and 48 hours for quantitative analysis. Duplicate samples were taken and stored at approximately -20°C for further analysis if necessary.

Test solutions

Vehicle:
yes
Details on test solutions:
An amount of test material (200 mg) was dissolved in reconstituted water with the aid of ultrasonication for approximately 20 minutes, and the volume adjusted to 2 litres to give the 100 mg/L test concentration. The prepared concentration was inverted several times to ensure adequate mixing and homogeneity. The concentration and stability of the test material in the test preparations were verified by chemical analysis at 0 and 48 hours.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: first in star daphnia magna
- Source: in -house laboratory cultures
- Age at study initiation (mean and range, SD): less than 24 hours old
- Method of breeding: Culture conditions ensured that reproduction was by parthenogenesis.
- Feeding during test - Food type: suspension of algae (Chlorella sp.).
- Frequency: daily

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h

Test conditions

Hardness:
approximate theoretical total hardness of 250 mg/L as CaC03
Test temperature:
Temperature ranged from 21.3 C at 0 hour to 20.6 C at 24 and 48 hour test vessels
Temperature ranged from 21.3 C at 0 hour to 20.6 to 20.8 C at 24 hr and 20.6 to 20.7 C at 48 hour for control vessels
pH:
pH 7.8 +/- 0.2 for test vessels
pH 8.0 at 0 hour and 48 hr for controls
Dissolved oxygen:
air saturation value (ASV) of 96 % at 0 and 48 hour for test vessels( one value of 94%)
air saturation value (ASV) of 96 % at 0 ( one 94%) and all 94% at 48 hour for control vessels
Nominal and measured concentrations:
Analysis of the test preparations at 0 and 48 hours showed measured test concentrations to range from 97% to 98% of nominal value and so it was considered justifiable to estimate the EC50 values in terms of the nominal test concentrations only.
Details on test conditions:
TEST SYSTEM
- Test vessel: 250 mL glass jars
- The test vessels were then covered to reduce evaporation
- 250 mL glass jars , approximately 200 mL of test preparation
- Not aerated
- No. of organisms per vessel: 5 daphnids were placed in each test and control vessel at random
- No. of vessels per concentration (replicates) and No. of vessels per control (replicates): 4 replicate test and control vessels were prepared.
-The test preparations were not renewed during the exposure period.

TEST MEDIUM / WATER PARAMETERS: Water temperature was recorded daily throughout the test. Dissolved oxygen concentrations and pH were recorded at the start and termination of the test. The pH and dissolved oxygen concentration were measured

OTHER TEST CONDITION: test and control vessels were maintained in a temperature controlled room at 20.6 C to 21.4 C with a photoperiod of 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods. The daphnids were not individually identified, received no food during exposure and the vessels were not aerated.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Any immobilisation or adverse reactions to exposure were recorded at 24 and 48 hours after the start of exposure. The criterion of effect used was that Daphnia were considered to be immobilised if they were unable to swim for approximately 15 seconds after gentle agitation. An estimate of the EC50 values was given by inspection of the immobilisation data

TEST CONCENTRATIONS
Water samples were taken from the control (replicates R1 -R2 pooled) and the 100 mg/L test group (replicates R1-R2 and R3 -R4 pooled) at 0 and 48 hours for quantitative analysis. Duplicate samples were taken and stored at approximately -20°C for further analysis if necessary.

- Range finding study
- Test concentrations: eries of nominal test concentrations of 1.0, 10 and 100 mg/L.
- Results used to determine the conditions for the definitive study: Based on the results of the range-finding test a "Limit test" was conducted at a concentration of 100 mg/L to confirm that at the maximum concentration given in the OECD/EEC Test Guidelines, no immobilisation or adverse reactions to exposure were observed.
Reference substance (positive control):
yes
Remarks:
potassium dichromate as the reference material was conducted using test concentrations of 0.32,0.56 , 1 .0, 1.8 and 3.2 mg/L

Results and discussion

Effect concentrations
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% CL
Details on results:
n the range finding study no immobilisation was observed at the test concentrations of 1.0, 10 and 100 mg/L.There was no immobilisation in 20 daphnids exposed to a test concentration of 100 mg/L for a period of 48 hours. The No Observed Effect Concentration after 24 and 48 hours exposure was 100 mg/L. The No Observed Effect Concentration is based upon zero immobilisation at this concentration.
Results with reference substance (positive control):
The No Observed Effect Concentrations after 24 and 48 hours were 1.0 mg/L and 0.56 mg/L respectively. The No Observed Effect Concentration is based upon zero immobilisation at this concentration.

The results from the positive control with potassium dichromate were within the normal range for this reference material. The mean 48-Hour ECso value calculated from all positive controls was 0.78 mg/L (sd = 0.24).
Reported statistics and error estimates:
An estimate of the EC50 value at 3 hours was given by inspection of the immobilisation data. The EC50 values and associated confidence limits at 24 and 48 hours were calculated using the trimmed Spearman-Karber method (Hamilton et a1 1977) using the ToxCalc computer software package (ToxCalc 1999).

Any other information on results incl. tables

The test preparations were observed to be clear, colourless solutions throughout the duration of the test. While there were no treatment related differences for oxygen concentration, concentration dependent differences in pH were observed throughout the test.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
The test is considered invalid if >= 10% of the control daphnids appear to be immobilised or stressed after 48 hours( test result was 0%) or if the oxygen concentration of the control vessels falls below 60% of Air Saturation Values (ASV) at the end of t
Conclusions:
The acute toxicity of the test material to the freshwater invertebrate Daphnia magna has been investigated and gave a 48-Hour ECS0 of greater than 100 mg/L. Correspondingly the No Observed Effect Concentration was 100 mg/L.