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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
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report date:
2008

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes (incl. QA statement)

Test material

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 100 mg test item was transferred to 1 l growth medium in a 2 l flask with a drain port near the bottom. The preparation was stirred at 200 rpm for 48 h at 20°C. To exclude insoluble parts from the test media, the test preparation was filtered by using a 0.22 µm filter (Millipore MCE-MF, cellulose nitrate and acetyl cellulose, no. GSWP04700) without pre-filtration.
- Eluate: Filtration of test item particles to separate the eluate (0.22 µm filter; Millipore MCE-MF, cellulose nitrate and acetyl cellulose, no. GSWP04700) without pre-filtration. The obtained test solution representing the highest concentration was diluted with growth medium using a spacing factor of 2 and 10 to prepare the other 5 test concentrations,

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Source (laboratory, culture collection): SAG, Culture Collection of Algae at Pflanzenphysiologisches Institut of the Unversity of Göttingen, Albrecht von Haller Institut, Untere Klarspüle 2, 37073 Göttingen, Catalogue No. 86.81
- Method of cultivation: Stock culture were maintained according to OECD guidelines. Three days prior to testing a pre-culture was established in OECD growth medium to obtain exponentially growing algae for the test.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
None

Test conditions

Hardness:
A sterilized synthetic growth medium (OECD medium) according to OECD 201 was used for culture and preparation of the test medium.
Test temperature:
22.0-22.5°C
pH:
Controls: 7.47-8.17; test cultures: at the beginning 7.26-7.47, at the end of test 7.95-8.04
Dissolved oxygen:
-
Salinity:
-
Nominal and measured concentrations:
Nominal: 0.63, 6.25, 12.5, 25.0, 50.0 and 100 mg/l; measured: all < 1.1 µg/l
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): Covered with silicone-sponge caps (sterilized prior to use)
- Material, size, headspace, fill volume: 250 ml conical glass flasks
- Initial cells density: 10,000 cells/ml
- No. of organisms per vessel: 1,000,000 cells
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
Reference substance (positive control):
yes

Results and discussion

Effect concentrations
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Details on results:
All EC50 and NOEC values were estimated to be < 1.13 µg/l (LOQ of chem. analysis)

Applicant's summary and conclusion

Conclusions:
The ErC50 for growth rate was calculated to be 100 mg/l based on nominal loading. The EC50 values for yield and biomass were at loadings of 32.6 and 52.6 mg/l, resp. The NOEC for all parameters was determined to be 6.25 mg/l nominal loading. Chemical analysis: conc. < 1.13 µg/l in all samples.