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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:
17 November 1992 - 16 March 1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles. Limited information available to verify the composition of the used test substance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1993
Report Date:
1993

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
(1984)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): KY-ET
- Substance type: light yellow solid
- Physical state: solid
- Stability under test conditions: Stable in water for at least 48 hours
- Storage condition of test material: Room temperature in the dark

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Sampling method: At t = 0 and t = 48h, duplicate samples of 10 mL were taken from the vehicle control and the solutions containing 10%, 32% and 100% of filtrate. Simultaneously, reserve samples of 25 mL were taken from all test solutions.
- Sample storage conditions before analysis: -20 degrees C

Test solutions

Vehicle:
yes
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A supersaturated solution of 1000 mg/L nominal was prepared by stirring for 48h; Cremophor RH40 was added as dispersant. After stirring, the saturated solution was filtered and the filtrate was diluted further with ISO-medium with the dispersant Cremophor RH40 to concentrations of 10, 18, 32, 56 and 100% of the filtrate.
- Controls: blank, Cremophor RH40 100 mg/L
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Cremophor RH40
- Concentration of vehicle in test medium (stock solution and final test solution): 100 mg/L
- Evidence of undissolved material (e.g. precipitate, surface film, etc): After filtering, clear without substance deposits

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Source: in-house culture
- Age at study initiation (mean and range, SD): < 24 hours
- Method of breeding: new batch with <3d old animals; 4 wk max age; renewal every 7d (half medium); daily feeding with freshwater algae

Study design

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

Test conditions

Hardness:
250 mg/L CaC03
Test temperature:
19.5-20.5 degrees C
pH:
7.8-8.1
Dissolved oxygen:
8.1-9.7 mg/L
Nominal and measured concentrations:
Blank and vehicle controls: nominal = 0 mg/L; measured = 0 mg/L
Test Substance:
Nominal = 10% of filtrate (100 mg/L); measured t0 = 0.14 mg/L, t48 = 0.083 mg/L; mean concentration = 0.11 mg/L
Nominal = 32%' of filtrate (320 mg/L);measured t0 = 0.46 mg/L, t48 = 0.25 mg/L; mean concentration = 0.36 mg/L
Nominal = 100% (1000mg/L); measured t0 = 1.0 mg/L, t48 = 0.74 mg/L; mean concentration = 0.87 mg/L
Details on test conditions:
TEST SYSTEM
- Material, size, headspace, fill volume: glass, 100 mL
- Aeration: None
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Milli-Q water (reverse osmosis purified tap water)

OTHER TEST CONDITIONS
- Adjustment of pH: None
- Photoperiod: 16 hours

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : imobilization (including mortality) at 24 and 48 hours

TEST CONCENTRATIONS
The low solubility of test substance meant a supersaturated stock solution of nominal 1000 mg/L was made by stirring the substance for 48 h. The resulting solution was then filtered through a paper filter to give a substance-deposit free filtrate. This filtrate was subsequently diluted with ISO medium containing 100 mg/L of the dispersant Cremophor RH40 which resulted in the following test concentrations:
0% (blank control, 100mg/L Cremophor (vehicle control)), 10%, 18%, 32%, 56%, 100% of filtrate. The amount of test substance was later measured at both t = 0h and t = 48h in the controls, and in the 10%, 32%, and 100% of filtrate test concentrations.
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrations
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 0.87 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: In the final test solutions no precipitation was observed.
- No effects were observed at the tested concentrations. The 48h-EC50 value was determined to be higher than 0.87 mg/L, which is the highest test concentration. Since this exceeds the maximum solubility of KY-ET in water (0.002 mg/L), it can be concluded that the 48h-EC50 value is above the maximum solubility of KY-ET in water.
Results with reference substance (positive control):
- Results with reference substance valid? Yes
-48h EC50: >0.32 and < 0.56 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
No effects were observed at the tested concentrations. The 48h-EC50 value was determined to be higher than 0.87 mg/L, which is the highest test concentration. Since this exceeds the maximum solubility of KY-ET in water (0.002 mg/L), it can be concluded that the 48h-EC50 value is above the maximum solubility of KY-ET in water.
Executive summary:

An Acute Immobilization Study was performed with Daphnia magna according to OECD 202. The test was performed using filtrates of a supersaturated solution of KY-ET. Three of the filtrate levels (10%, 32% and 100%) were analyzed for actual KY-ET concentrations. The mean measured concentrations were 0.11, 0.36 and 0.87 mg/L, respectively.

No effects were observed at the tested concentrations. The 48h-EC50 value was determined to be higher than 0.87 mg/L, which is the highest test concentration. Since this exceeds the maximum solubility of KY-ET in water (0.002 mg/L), it can be concluded that the 48h-EC50 value is above the maximum solubility of KY-ET in water.