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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:
2017-2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
April 13, 2004
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
white crystalline powder

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Samples for possible analysis were taken from all test concentrations and the control according to the schedule below. The method of analysis is described in the appended Analytical Report.

Frequency at t=0 h and t=48 h
Volume 2.0 mL from the approximate centre of the test vessels
Storage Samples were stored in a freezer (≤-15°C) until analysis at the analytical laboratory of the Test Facility.

At the end of the exposure period, the replicates were pooled at each concentration before sampling.
Additionally, reserve samples of 2.0 mL were taken at the same frequency for possible analysis.

Test solutions

Vehicle:
yes
Details on test solutions:
Preparation of test solutions started with the highest concentration of 10 mg/L (final test) or 100 mg/L (range-finding test) applying 26-27 minutes of magnetic stirring to accelerate dissolution of the test item in medium. Lower test concentrations were prepared by subsequent dilutions of the highest concentration in test medium. All test solutions were clear and colorless at the end of the preparation procedure.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Water flea
- Source: In-house laboratory culture with a known history
- Age of parental stock (mean and range, SD): at least third generation
- Feeding during test: no
- Food type: a suspension of fresh water algae
- Frequency: Daily

ACCLIMATION
- Type and amount of food: a suspension of fresh water algae
- Feeding frequency: Daily
- Health during acclimation (any mortality observed): Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.

Study design

Test type:
static
Water media type:
freshwater
Remarks:
M7, as prescribed by Dr. Elendt-Schneider
Limit test:
no
Total exposure duration:
48 h

Test conditions

Test temperature:
20°C
pH:
8-8.1
Dissolved oxygen:
8.8-9 mg/L
Nominal and measured concentrations:
0.10, 0.18, 0.32, 0.56 and 1.0 mg/L.
The concentrations measured at the start of the test were at 94-109% of the nominal concentration. During the exposure period the measured concentrations decreased to 78-90% of the nominal concentration. Based on these results, the average exposure concentrations were calculated and used to determine the effect parameters.
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 60 mL, all-glass
- Aeration: No aeration of the test solutions.
- No. of organisms per vessel: 5 daphnids per vessel containing 50 mL of test solution
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): 4
- Biomass loading rate: 5 daphnids per vessel containing 50 mL of test solution

TEST MEDIUM / WATER PARAMETERS: M7, as prescribed by Dr. Elendt-Schneider

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours photoperiod daily
- Light intensity: /

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobility

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: 0, 0.1, 1, 10, 100 mg/L
- Results used to determine the conditions for the definitive study: yes
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
0.39 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
0.3 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Results with reference substance (positive control):
The actual responses in this reference test with K2Cr2O7 are within the ranges of the expected responses at the different concentrations, i.e. the 48h-EC50 was between 0.3 and 1.0 mg/L. Hence, the sensitivity of this batch of D. magna was in agreement with the historical data collected at Charles River Den Bosch.
The 24h-EC50 was 0.59 mg/L with a 95% confidence interval between 0.52 and 0.68 mg/L.
The 48h-EC50 was 0.41 mg/L with a 95% confidence interval between 0.34 and 0.46 mg/L.
Reported statistics and error estimates:
24h-EC50 0.39 [0.33-0.45] (95% confidence interval)
48h-EC50 0.30 [0.26-0.34] (95% confidence interval)

Any other information on results incl. tables

The test conditions remained within the limits prescribed by the study plan (pH: 6-9, not varying by more than 1.5 units; oxygen:³3 mg/L at the end of the test).

The temperature continuously measured in a temperature control vessel was maintained at 20°C during the test, and complied with the requirements as laid down in the study plan (18-22°C, constant within 2°C).

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
In conclusion, the 48h-EC50 for Daphnia magna exposed to CH02241 was 0.30 mg/L based on average exposure concentrations (95% confidence interval between 0.26 and 0.34 mg/L).
Executive summary:

The objectiveof the study was to evaluate CH02241 for its ability to generate acute toxic effects on the mobility of Daphnia magna during an exposure period of 48 hours and, if possible, to determine the EC50after 24 and 48 hours of exposure.

The study procedures described in this report were based on the OECD guideline No. 202, 2004.

The batch of CH02241 tested was a white crystalline powder and completely soluble in test medium at the concentrations tested.

A final test was performed based on the results of a preceding range-finding test.Twenty daphnids per group (5 per replicate, quadruplicate) were exposed to an untreated control and to0.10, 0.18, 0.32, 0.56 and 1.0 mg/L. The total exposure period was 48 hours and samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the test.

No immobility was observed in the control and the two lowest test concentrations, while immobility increased with increasing concentration at the highest three test concentrations.

Samples taken from all concentrations were analysed. The concentrations measured at the start of the test were 94-109% of the nominal concentration. During the exposure period, the measured concentrations decreased to 78-90% of the nominal concentration.Based on these results, the average exposure concentrations were calculated and used to determine the effect parameters.

The study met the acceptability criteria prescribed by the study plan and was considered valid.

In conclusion, the 48h-EC50for Daphnia magna exposed to CH02241 was 0.30 mg/L based on average exposure concentrations (95% confidence interval between 0.26 and 0.34 mg/L).