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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:
190-021 February 2020
Reliability:
1 (reliable without restriction)
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
yes
Vehicle:
yes
Details on test solutions:
Because the test item is poorly soluble in water, test item stock solution was prepared using a saturated solution method according to the Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures, OECD No. 23.
Saturated test item solution (nominal loading rate of 100.0 mg/L) was prepared by dispersing/dissolving the amount of test item into the test medium (ISO Medium) two days before the start of the experiment. This solution was shaken for about 24 hours at approximately 30°C and then equilibrated for about 24 hours at approximately 20°C.
The non-dissolved test material was removed by filtration through a fine (0.22 μm) filter to give the appropriate 100 % saturated solution.
Test item solution was prepared fresh for each renewal using the method described above. The test solution was prepared just before introduction of the Daphnia (start of the treatments).
Test organisms (species):
Daphnia magna
Test type:
semi-static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Hardness:
The reconstituted water (ISO medium) had a total hardness of 247 mg/L (as CaCO3).
Test temperature:
The test temperature was in the range of 20.6 – 20.8°C measured in the test vessels.
pH:
The pH was measured at the start and at the end of the renewal periods in one test vessel both in the control and test item group and was in the range of 7.72 – 7.98.
Dissolved oxygen:
The dissolved oxygen concentration was measured in the control and in the test concentration in one replicate at the start and at the end of the renewal periods and was in the range of 7.6 – 8.6 mg/L.
Reference substance (positive control):
no
Key result
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Validity criteria fulfilled:
yes
Conclusions:
The LC50 >100 mg/L based on nominal loading rate. The measured concentration was below the limit of quantification.
Executive summary:

Acute toxicity of CAS 577978-76-8 on Daphnia magna was assessed in an acute immobilisation test, over an exposure period of 48 hours in a semi-static test system following the OECD 202 test guideline in accordinace with GLP.

Because no toxic response was observed during the preliminary range-finding test, a Limit Test was carried out using only one test concentration at 100 mg/L nominal loading rate and one control group in the definitive test.

The test concentration was analytically determined at the start and at the end of the renewal periods, but the test item concentration could not be analytically quantified during the whole experiment, consequently, the measured concentrations were below the Limit of Quantification (LOQ = 0.484 mg/L).

The biological results are based on nominal loading rate.

The 48 hr LC50 is >100 mg/l.

Description of key information

Acute toxicity of CAS 577978-76-8 on Daphnia magna was assessed in an acute immobilisation test, over an exposure period of 48 hours in a semi-static test system following the OECD 202 test guideline in accordinace with GLP.

Because no toxic response was observed during the preliminary range-finding test, a Limit Test was carried out using only one test concentration at 100 mg/L nominal loading rate and one control group in the definitive test.

The test concentration was analytically determined at the start and at the end of the renewal periods, but the test item concentration could not be analytically quantified during the whole experiment, consequently, the measured concentrations were below the Limit of Quantification (LOQ = 0.484 mg/L).

The biological results are based on nominal loading rate.

The 48 hr LC50 is >100 mg/l.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
100 mg/L

Additional information