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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:
July 22 - 25, 2008
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to OECD and EC guidelines and according to GLP principles. Study performed without analytical support.
Cross-reference
Reason / purpose for cross-reference:
reference to same study

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
Principles of method if other than guideline:
ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Details on test material:
- Name of test material (as cited in study report): Nikkol VC-IP
- Substance type: Colourless liquid (determined at NOTOX)
- Physical state: Liquid
- Stability under test conditions: stability in water unknown
- Storage condition of test material: At room temperature in the dark
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not applicable.

Sampling and analysis

Analytical monitoring:
no
Details on sampling:
Not applicable.

Test solutions

Vehicle:
no
Details on test solutions:
Preparation of test solutions started with a loading rate of 100 mg/l. This solution was stirred for 24 hours, which resulted in a slightly hazy
dispersion containing undissolved material and an oily-like floating layer on the surface. The dispersion was consequently left to stabilise for 30
minutes after which the middle fraction was collected and filtered through glass wool to remove the majority of non-dissolved material. The lower testconcentrations were prepared by subsequent dilution of the filtrate in test medium. The final test solutions were all clear and colourless.

After preparation, volumes of 50 ml were added to each replicate of the respective test concentration. Subsequently, 1 ml of an algal suspension was added to each replicate providing a cell density of 10^4 cells/ml.

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Strain: NIVA CHL 1
- Source (laboratory, culture collection): In-house laboratory culture
- Age of inoculum (at test initiation): not indicated
- Method of cultivation: Algae stock cultures were started by inoculating growth medium with algal cells from a
pure culture on agar. The suspensions were continuously aerated and exposed to light in a climate room at a
temperature of 21-24°C.

ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): stock culture medium is M1 (according to the NPR
6505, formulated using Milli-Ro water); test medium and pre-culture medium is M2 (according to the OECD
201 Guideline, formulated using Milli-Q water (tap water purified by reverse osmosis and subsequently
passed over activated carbon and ion-exchange cartridges) preventing precipitation.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Post exposure observation period:
No post exposure observations.

Test conditions

Hardness:
0.24 mmol/l (24 mg CaCO3/l)
Test temperature:
22.7 - 23.4°C.
pH:
8.1 - 8.2 (measured)
Dissolved oxygen:
no data
Salinity:
no data
Nominal and measured concentrations:
1.0, 10 and 100% of a glass wool filtered solution prepared at a loading rate of 100 mg/l.
Details on test conditions:
TEST SYSTEM
- Test vessel: 100 ml, all-glass, containing 50 ml of test solution
- Initial cells density: 10000 cells/ml
- Control end cells density: 180000 cells/ml
- No. of vessels per concentration (replicates): 6 replicates of the control and the filtrate, 3 replicates of each of the dilutions from the filtrate, 1 replicate of each test concentration without algae
- No. of vessels per control (replicates): 6 replicates of the control
GROWTH MEDIUM
- Standard medium used: yes
OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: 82 to 94 μE.m-2.s-1 using TLD-lamps of the type ‘Cool-white’ of 30 Watt.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : 0, 24, 48 and 72 h
- Determination of cell concentrations: spectrophotometer
TEST CONCENTRATIONS
- Spacing factor for test concentrations: 0 and 1 and 10% dilution of the filtrate and undiluted filtrate
- Range finding study: the study is a combined limit/range finding study
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrations
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 0.09 mg/L
Nominal / measured:
nominal
Basis for effect:
growth rate
Remarks on result:
other: Solubility in medium is unknown and solubility in water is < 0.09 mg/l.
Details on results:
- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no abnormalities observed
- Any stimulation of growth found in any treatment: no
Results with reference substance (positive control):
Results with reference substance valid: Yes
- EC50: The EC50 for growth rate reduction (ERC50: 0-72h) was 1.7 mg/l with a 95 % confidence interval ranging from 1.1 to 2.7 mg/l.
Reported statistics and error estimates:
no data

Any other information on results incl. tables

No other information.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the conditions of the present study with Pseudokirchneriella subcapitata, no reduction of growth rate or inhibition of yield was recorded at or
below the concentration present in a glass wool filtered solution prepared at a loading rate of 100 mg/l (NOEC > 0.09 mg/l).

Hence, both the EC50 for growth rate reduction (ERC50: 0-72h) and the EC50 for yield inhibition (EYC50: 0-72h) exceeded the maximum solubility in test medium.