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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:
04 May 2018 - 18 Jul 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Vehicle:
yes
Remarks:
water
Details on test solutions:
A stock preparation with a test item concentration of 100 mg/L was freshly prepared.
Out of the saturated solution five concentration levels were tested in a geometrical series with a spacing factor of √10: 1.00 - 3.16 - 10.0 - 31.6 - 100% of the saturated solution, corresponding to the geometric mean measured test item concentrations: 0.0100* – 0.0135* – 0.0224 – 0.169 – 1.82 mg/L (* = ½ LOQ).
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
Test organism: Pseudokirchneriella subcapitata HINDAK, SAG 61.81
Origin:
Sammlung von Algenkulturen (SAG), Pflanzenphysiologisches Institut der Universität Göttingen, Göttingen, Germany
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Test temperature:
22.0-24.0 °C
pH:
7.7 - 9.1
Details on test conditions:
The study was performed as a static test in open vessels under culture conditions. The flasks contained 100 mL either reconstituted water or test medium (test item group).
The duration of exposure was 72 hours. The algal biomass in each flask was determined daily during the exposure period via Chlorophyll a-fluorescence. Microscopic evaluation of the cells at the start and at the end of the incubation period was carried out.
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 0.097 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
other: yield
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 1.82 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
0.081 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 95% CL: 0.0382 - 0.122
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
0.01 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Results with reference substance (positive control):
- Results with reference substance valid? Yes
- EC50: 72-h EC50 (growth rate) = 0.574 mg/L (95% CL: 0.549 - 0.596)
Validity criteria fulfilled:
yes
Conclusions:
The 72-h EC50 value and 72-h EC10 value based on growth rate were determined to be > 1.82 mg/L and 0.0806 mg/L, respectively.

Description of key information

OECD 201: EC50 (72 h, growth rate) > 1.82 mg/L; EC10 (72 h, growth rate) = 0.0806 mg/L

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:
0.081 mg/L

Additional information