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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2007-03-26 to 2007-09-04
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Qualifier:
according to
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
GLP compliance:
yes (incl. certificate)
Remarks:
: Certificate issued by the Swiss GLP monitoring authorities
Analytical monitoring:
yes
Details on sampling:
- Sampling method: Duplicate samples were taken from the test medium and the control at the start and at the end of the test. At the end of the test, the contents of the respective replicates were combined prior to the sampling.
- Sample storage conditions before analysis: The samples were deep-frozen immediately after sampling and .stored deep-frozen (at about -20 °C) until analysis. Based on pre-experiments for investigation of the storage stability (without GLP), the test item proved to be stable in the test water under these storage conditions.
- The concentrations of the test substance were analytically measured in the duplicate test medium samples taken at the start and the end of the test. From the control samples, one of the duplicate samples was analyzed from the corresponding sampling times.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test medium was prepared by dissolving 30.3 mg of test substance completely in 300 mL of test water using intense stirring for 15 minutes at room temperature. The test medium was freshly prepared just before introduction of the daphnids (i.e., start of the test). The actual concentration of the test substance in the test medium was analytically determined.
- Controls: yes, concurrent no treatment
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: water flea
- Strain: Straus
- Source: A clone of this species (defined by the supplier as clone 5) was originally supplied by the University of Sheffield/UK in 1992.
- Method of breeding: Since 1992, the clone has been bred in the laboratories of RCC in reconstituted water of the quality identical to the water quality used in the tests (in respect to pH, main ions, and total hardness) and under temperature and light conditions identical to those of the tests.
- Feeding during test: no

ACCLIMATION: no data

QUARANTINE (wild caught): none
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Post exposure observation period:
none
Hardness:
2.5 mmol/L (250 mg/L as CaCO3)
Test temperature:
20 °C (the test was performed in a temperature-controlled room, monitored continuously)
pH:
7.8-7.9
Dissolved oxygen:
7.2
Salinity:
no data
Nominal and measured concentrations:
100 mg/L (nominal concentration); 119 mg/L (mean meausred concentration)
Details on test conditions:
TEST SYSTEM
- Test vessel: 100 ml glass vessels
- Type (delete if not applicable): no data
- Material, size, headspace, fill volume: glass, 100 mL, 50 mL, 50 mL
- Aeration: The test water was aerated prior to the start of the study until oxygen saturation was reached. During the test period, the test water was not aerated.
- Type of flow-through (e.g. peristaltic or proportional diluter): not applicable
- Renewal rate of test solution (frequency/flow rate): not applicable
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): not applicable
- Biomass loading rate: not applicable

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: purified water
- Total organic carbon: no data
- Particulate matter: no data
- Metals: no data
- Pesticides: no data
- Chlorine: 0.075 mmol/L (65 mg/L) as KCl
- Alkalinity: 0.8 mmol/L
- Ca/mg ratio: 4:1 (based on molarity)
- Conductivity: no data
- Culture medium different from test medium: no data
- Intervals of water quality measurement: At the start and at the end of the test, the pH, the dissolved oxygen concentrations and the water temperature were determined in the single test concentration and the control. The appearance of the test medium was visually recorded at the start of the test and after 24 and 48 hours.

OTHER TEST CONDITIONS
- Adjustment of pH: no data
- Photoperiod: 16 hours light/8 hours dark (30 min transition period)
- Light intensity: 490-650 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Immobilization was defined as those organisms which are not able to swim within 15 seconds after gentle agitation of the test container and was monitored after 48 hours of continuous treatment with the test substance.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: not applicable
- Justification for using less concentrations than requested by guideline: A limit test was performed in accordance with the test guidelines to demonstrate that the test
item has no toxic effect on the test organisms up to the test item concentration of 100 mg/L. Thus, a single nominal test substance concentration of 100 mg/L was tested. Additionally, a control was tested in parallel (test water without addition of the test substance).
- Range finding study: Yes
- Test concentrations: no data
- Results used to determine the conditions for the definitive study: no data
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 119 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
- Behavioural abnormalities: no
- Observations on body length and weight: no
- Other biological observations: no
- Mortality of control: no
- Other adverse effects control: no
- Abnormal responses: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: no
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Mortality: no data
- EC50/LC50: The result of the latest positive control test in December 2006 (48-hour EC50: 0.73 mg/L, RCC Study No. B10664) indicated that the sensitivity of the test organisms was within the historical range of the RCC laboratory (48-hour EC50 from 1996 to 2006: 0.53-1.1 mg/L).

Reported statistics and error estimates:
no data

At the start and the end of the test, the analytically determined concentration of the test substance in the test medium was 132 and 105 mg/L, respectively. The mean measured concentration of the test substance was 119 mg/L. All biological results were based on the nominal concentration of the test substance of 100 mg/L.

At the beginning and the end of the test period, the dissolved oxygen concentration in the test medium and the control was at least 7.2 mg/L. The pH of the test medium and the control was between 7.8 and 7.9. The water temperature was 20 deg C at the start and the end of the test.

Validity criteria fulfilled:
yes
Conclusions:
The acute toxicity of T002675 to Daphnia magna was determined in a 48-hour limit test under static conditions according to OECD guideline 202. Based on mean measured concentration, the 48-h EC50 was determined to be > 119 mg/L. The results of the test can be considered reliable without restriction.

Description of key information

The study of Bätscher (2017), investigating the acute toxicity of T002675 in Daphnia magna according to OECD guideline 202, was considered as the key study for endpoint coverage. An EC50 > 119 mg/L (based on analytically test concentrations) was found after an exposure of 48 hours in a static limit test in freshwater. Based on the results it can be concluded that T002675 is not harmful to aquatic invertebrates.

Key value for chemical safety assessment

Additional information