Registration Dossier

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:
November 27, 2007-December 14, 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study has been performed according to OECD and EC guidelines and according to GLP principles.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report Date:
2008

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
Qualifier:
equivalent or similar to
Guideline:
ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Physical state: Blue solid lumps
- Stability under test conditions: Stable
- Storage condition of test material: at room temperature in the dark

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: all test concentrations and control
- Sampling method: 40 ml from the approximate centre of the test vessels
- Sample storage conditions before analysis: Samples were stored in a refrigerator until analysis.

Test solutions

Vehicle:
no
Details on test solutions:
Preparation of test solutions started with a loading rate of 100 mg/l. The aqueous mixture was treated with ultrasonic waves for 5 minutes, followed by a 24-hour magnetic stirring period and a 2¼ hour stabilisation period. The resulting mixture was slightly blue and contained test substance particles, precipitate and a floating layer. Therefore, the mixture was passed over glass wool, after which it was clear and colourless.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Source: In-house laboratory culture with a known history.
- Age at study initiation (mean and range, SD): young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.
- Method of breeding: With newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an all-glass culture vessel.
- Feeding during test: no feeding

Study design

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

Test conditions

Hardness:
180 mg/l expressed as CaCO3
Test temperature:
The temperature of the test medium was 21.0°C at the start of the test. The temperature continuously measured in a temperature control vessel varied between 19.4 and 20.7 °C during the test, and complied with the requirements as laid down in the protocol (18-22°C, constant within 2°C).

pH:
7.7 - 7.9
Dissolved oxygen:
8.8 - 9.4 mg/L
Nominal and measured concentrations:
Loading rate 0 mg/L t=0h: TOC = 0.6626 mg/L
Loading rate 0 mg/L t=48h: TOC =0.7624 mg/L
Loading rate 100 mg/L t=0h: TOC = 1.013 mg/L
Loading rate 100 mg/L t=48h: TOC = 0.7183 mg/L
The TOC contents in treated samples were comparable to those in control samples, indicating that the actual test substance concentration was very low. This is not unexpected considering the presence of precipitate and a floating layer in the solution, which were removed by passing the solution over glass wool.
Details on test conditions:
TEST SYSTEM
- Test vessel: 60 ml, all-glass
- Aeration: No aeration of the test solutions
- No. of organisms per vessel: 5 per vessel containing 50 ml of test solution
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 20 daphnids exposed
- No. of vessels per vehicle control (replicates): 4


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Adjusted ISO medium
- Total organic carbon: o.66 mg/L
- Culture medium different from test medium: yes, for culturing M7 medium is used.

OTHER TEST CONDITIONS
- Photoperiod: 16 hours photoperiod daily


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : EC50 daily


TEST CONCENTRATIONS
- Spacing factor for test concentrations: limit test with a water accommodated fraction prepared at a loading rate of 100 mg/L
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrations
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
loading rate
Basis for effect:
mobility
Details on results:
No immobility was observed in the control or the test concentration.
Results with reference substance (positive control):
- Results with reference substance valid? yes
Concentration
(mg/l) No.Exposed % immobile
24h 48h

Blank-control 20 0 0
0.10 20 5 5
0.18 20 0 0
0.32 20 5 15
0.56 20 30 75
1.0 21 90 100
1.8 20 100 100

- EC50/LC50:
The 48h-EC50 was 0.45 mg/l with a 95% confidence interval between 0.35 and 0.56 mg/l.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the conditions of the present study the test substance did not induce acute immobilisation of Daphnia magna at a loading rate of 100 mg/l after 48 hours of exposure (NOEC).

Due to the very low solubility of the test substance in water, concentration levels that might be toxic for daphnids could not be reached. Hence the 48h-EC50 was above a loading rate of 100 mg/l.