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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
march 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: crystalline
Details on test material:
White powder
Specific details on test material used for the study:
Batch 562371/016

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
Strain : Chodat
Family : Chlorophyceaa
Order : Chlorococcales
Obtained in Dec 2009 from the institut fur Pflanzenphysiologie of Universitat Gottingen.
The Alga are kept as stock culture on solid agar at 8°C.

Study design

Test type:
not specified
Water media type:
freshwater
Total exposure duration:
72 h
Post exposure observation period:
0, 24, 48, 72h

Test conditions

Test temperature:
21.0 to 25.0°C
pH:
7.3 to 7.7
Details on test conditions:
light intensity : 6800 lux
Reference substance (positive control):
yes
Remarks:
Dichromate (CAS 7778-50-9)

Results and discussion

Effect concentrationsopen allclose all
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
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
ca. 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
ca. 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Details on results:
One valid main study was performed.
As the test item is poorly soluble in water, a saturated solution was prepared. this was done by shaking the nominal load with the appropriate amount of deionised water for 24 hours, followed by membrane filtration. The lower treatments were prepared by dilution of this saturated solution.
The study was performed using three concentrations containing 1, 10 and 100 mg/L.
The treatments were used to incubate the unicellular freshwater green alga Desmodesmus subspicatus for a period of 72 hours. The cell concentration of each replicate was determined by measuring the absorption of the cuvettes at 440 nm every 24 hours with a spectral photometer. With there measured values, the number of cells was calculated (linear correlation between cell concentration and adsorption given). Then the
growth rate, the area under the growth curve and the yield were determined.
The EC50s of potassium dichromate were tested in a current reference test. The values lay within the normal range of the laboratory.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The following results for the tests item were determined :
72h LOEC> 100mg/L (growth tae and biomass)
72h EC50 (growth rate and biomass) > 100mg/L
72h NOEC (growth rate and biomass) = 100 mg/L
Executive summary:

One valid main study was performed.

As the test item is poorly soluble in water, a saturated solution was prepared. this was done by shaking the nominal load with the appropriate amount of deionised water for 24 hours, followed by membrane filtration. The lower treatments were prepared by dilution of this saturated solution.

The study was performed using three concentrations containing 1, 10 and 100 mg/L.

The treatments were used to incubate the unicellular freshwater green alga Desmodesmus subspicatus for a period of 72 hours. The cell concentration of each replicate was determined by measuring the absorption of the cuvettes at 440 nm every 24 hours with a spectral photometer. With there measured values, the number of cells was calculated (linear correlation between cell concentration and adsorption given). Then the

growth rate, the area under the growth curve and the yield were determined.

The EC50s of potassium dichromate were tested in a current reference test. The values lay within the normal range of the laboratory.

The following results for the tests item were determined :

72h LOEC> 100mg/L (growth tae and biomass)

72h EC50 (growth rate and biomass) > 100mg/L

72h NOEC (growth rate and biomass) = 100 mg/L