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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:
03 January 2017 through 24 April 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
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
Test material form:
liquid
Specific details on test material used for the study:
BAtch No. : VE00466805
Purity : 93.5% (sum of two isomers)
Expiry Date : 23 January 2019

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
For the determination of the actual test item concentrations, duplicate samples were taken from each test concentration and the control at the start and at the end of the two 24-hour test medium renewal periods.

However, from the highest test concentration of 25mg/L, the last samples were taken after 24 hours, since all daphnids were dead at that observation time at this concentration.

For sampling from the aged test media, the contents of the respective replicates were combined prior to sampling.

All samples were stored frozen (at about -20 °C) immediately after sampling. Based on pre-experiments for investigation of the storage stability (non GLP IES Study 20160321), the test item was found to be stable in the test water under these storage conditions.

The concentrations of GR-50-3010 were analyzed in one of the duplicate test medium samples from the control and all test concentrations with surviving daphnids from the start and end of both test medium renewal periods.

Test solutions

Vehicle:
no
Details on test solutions:
The test medium of the highest nominal concentration of 25 mg/L was prepared by completely
dissolving 25.05 and 25.03 mg of test item in 1000 mL of test water using intense stirring for
24 hours at room temperature in the dark, on Day -1 and Day 0, respectively. Adequate volumes
of this test medium were diluted with test water to prepare the lower concentrations of test
media.
The test media were prepared just before the introduction of the daphnids (i.e., start of the test
and prior to the test medium renewal).

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
The study was performed with young daphnids of the species Daphnia magna Straus. A clone of this species (originally from the Daphnia Collection of the University of Basel/Switzerland in 2015) is successfully bred in IES Ltd Laboratories. The cultivation of the parental daphnids is performed in reconstituted water of the quality identical to the water quality used in the tests (with respect to pH, main ions, and total hardness) and under temperature and light conditions identical to those of the tests.

During breeding, daphnids were generally fed three times a week with an algal suspension of the green algae Desmodesmus subspicatus CHODAT, Strain No. 86.81 SAG, supplied by the Collection of Algal Cultures (SAG, Institute for Plant Physiology, University of Göttingen, 37073 Göttingen/Germany) and cultivated at IES Ltd Laboratories under standardized conditions or a mixture of this algal suspension and a commercial fish diet (Tetra Min® Hauptfutter, supplied by TETRA-Werke, 49324 Melle/Germany).

At the start of the test, the organisms used in the test were less than 24 hours old and were not first brood progeny.

Study design

Test type:
semi-static
Water media type:
freshwater
Remarks:
Reconstituted water according to ISO 6341.
Limit test:
no
Total exposure duration:
48 h

Test conditions

Hardness:
250 mg/L as CaCO3
Test temperature:
20 - 21 °C
pH:
pH 7.7 - 8.0
Dissolved oxygen:
Dissolved Oxygen : 8.4 - 8.9 mg O2/L
Nominal and measured concentrations:
The measured concentrations of GR-50-3010 in the test media of the nominal test
concentrations of 1.0 to 25 mg/L were between 100 and 104% of the nominal values at the start
of the two test medium renewal periods. Thus, the correct dosage of the test item could be
verified. During the test periods of 24 hours, the test item concentrations in the test media
decreased. At the end of the two test medium renewal periods, 31 to 77% of the nominal values
were found.
Details on test conditions:
The test was performed in 100-mL glass beakers filled with 50 mL of test medium. The test vessels were covered with a glass sheet to reduce the loss of water by evaporation and to avoid the entry of dust into the solutions as well as limit the volatilization of the test item from the test system.

The test was performed in a temperature-controlled room with continuous monitoring of the room temperature. The water temperature was in the range of 20-21 °C.

The daphnids were not fed during the test.

A 16-hour light to 8-hour dark cycle with a 30-minute transition period was used. Light intensity during the light period was approximately between 15 and 17 µmol m-2 s-1.
Reference substance (positive control):
yes
Remarks:
Potassium Dichromate - reference toxicity test performed at least twice a year.

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
6.4 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% CI : 5.7- 7.2 mg/L
Duration:
48 h
Dose descriptor:
EC0
Effect conc.:
1.9 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
17 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
1.9 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
other: Sub-lethal effect observations
Results with reference substance (positive control):
For evaluation of the quality of the daphnia clone and the experimental conditions, potassium
dichromate is tested as a positive control twice a year. The result of the latest positive control
test in October 2016 (24-hour EC50: 1.0 mg/L, IES Laboratories Study 20160278) showed that
the sensitivity of the test organisms was within the range given by the guideline (24-hour EC50:
0.60-2.1 mg/L).

Any other information on results incl. tables

A clear dose-response effect was observed during the study.

During the first 24 hours of the test, no immobilized test organisms were determined in the

control and up to and including the mean measured concentration of 4.1 mg/L.

100% immobilization of daphnids observed at

the highest mean measured test concentration of 17 mg/L after 48 hours exposure, 75 and 10%

immobilization at 7.5 and 4.1 mg/L respectively and 0% immobilization at the two lower tests

concentrations.

The test is considered to be valid, as in the control no daphnids showed immobilization or other signs of disease or stress (e.g., discolouration or unusual behaviour such as trapping at the surface of water). Furthermore, the dissolved oxygen concentration at the end of the test was ≥3 mg/L in all test vessels

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The test item GR-50-3010 had acute toxic effects on Daphnia magna in a 48-hour semi-static test.

The 48-hour EC50 was determined to be at the test concentration of 6.4 mg/L with 95%-confidence limits of 5.7 and 7.2 mg/L (based on mean measured concentrations).

The 48hr EC0 and NOEC was determined to be 1.9 mg/L and the 48 hr EC100, 17 mg/L.
Executive summary:

A clear dose-response effect was observed with 100% immobilization of daphnids observed at the highest mean measured test concentration of 17 mg/L after 48 hours exposure, 75 and 10% immobilization at 7.5 and 4.1 mg/L respectively and 0% immobilization at the two lower tests concentrations.

The test item GR-50-3010 had acute toxic effects on Daphnia magna in a 48-hour semi-static test.

The 48-hour EC50 was determined to be at the test concentration of 6.4 mg/L with 95%-confidence limits of 5.7 and 7.2 mg/L (based on mean measured concentrations).

The 48hr EC0 and NOEC was determined to be 1.9 mg/L and the 48 hr EC100, 17 mg/L.