[No public or meaningful name is available]

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

Test material information

Constituent 1

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.