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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
18 - 21 February 2020
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Vehicle:
yes
Test organisms (species):
Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Test temperature:
Culture temperature was checked at the beginning of the experiment and each day thereafter in a flask filled with water, in the climatic chamber. In addition, water temperature was continuously measured (with a min/max thermometer) within the climate chamber.
pH:
The range of the pH was 7.74 – 8.97 during the experiment.
Reference substance (positive control):
yes
Remarks:
Potassium dichromate
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Validity criteria fulfilled:
yes
Conclusions:
The ErC50 is >100 mg/l based on nominal loading rates.
Executive summary:

The effect of CAS 577978-76-8 test item was assessed on algal growth using the unicellular green alga Pseudokirchneriella subcapitata, over an exposure period of 72 hours.

Because a significant inhibition was not observed during the preliminary concentration range-finding test, a Limit Test was carried out using only one test concentration at 100.0 mg/L nominal loading rate and one control group.

The test concentration was analytically determined at the start and at the end of the experiment, but the test item concentration could not be analytically quantified during the 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 test design included six replicates at test concentration groups and six replicates for the untreated control.

Statistical comparisons of biomass, average specific growth rates and yield in control and in treated groups were carried out using 2 Sample t-Test (α = 0.05) by TOXSTAT software.

The ErL50, EbL50 and EyL50 values of the test item were determined directly from the raw data.

The ErC50 is >100 mg/l.

Description of key information

The effect of CAS 577978-76-8 test item was assessed on algal growth using the unicellular green alga Pseudokirchneriella subcapitata, over an exposure period of 72 hours.

Because a significant inhibition was not observed during the preliminary concentration range-finding test, a Limit Test was carried out using only one test concentration at 100.0 mg/L nominal loading rate and one control group.

The test concentration was analytically determined at the start and at the end of the experiment, but the test item concentration could not be analytically quantified during the 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 test design included six replicates at test concentration groups and six replicates for the untreated control.

Statistical comparisons of biomass, average specific growth rates and yield in control and in treated groups were carried out using 2 Sample t-Test (α = 0.05) by TOXSTAT software.

The ErL50, EbL50 and EyL50 values of the test item were determined directly from the raw data.

The ErC50 is >100 mg/l.

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L
EC10 or NOEC for freshwater algae:
100 mg/L

Additional information