Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
26 Oct. 1998 - 30 Oct. 1998
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP guideline study - but read-across

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report date:
1998

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
version 07 June 1984
GLP compliance:
yes

Test material

Constituent 1
Reference substance name:
Automatically generated during migration to IUCLID 6, no data available
IUPAC Name:
Automatically generated during migration to IUCLID 6, no data available
Details on test material:
other Test Substance:
SIPERNAT 820A, sodium aluminium silicate (Degussa) [CAS No. 1344-00-9]
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Melting point: ca. 1700 °C
- Boiling point: not relevant
- Vapour pressure: practically 0 Pa
- Water solubility (under test conditions): 48 mg/L (Sum of SiO2, Al, Na)
- Henry's law constant: not applicable
- log Pow: not applicable
- pKa: no data
- Stability in water: stable
- Stability in light: stable
- pH dependance on stability:


OTHER PROPERTIES (if relevant for this endpoint)
- Results of test for ready biodegradability: not applicable

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: stirring the suspensions for 24 h in 0.5 l ultrapure water, followed by filtration through paper filter.
- Eluate: Water extracts from 6250, 630, and 60 mg silicate/0.5 L, diluted to the target concentration
by additions of stock solutions needed for testing.
- Differential loading: yes
- Controls: without or with respective filtrates, but without algae
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): none
- Evidence of undissolved material (e.g. precipitate, surface film, etc): not specified

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: green alga
- Strain: CHODAT
- Source (laboratory, culture collection): Pflanzenphysiol. Inst. University of Göttingen/Germany
- Age of inoculum (at test initiation): see below
- Method of cultivation: preculture 3 days prepared before test from a stock culture

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Post exposure observation period:
none

Test conditions

Hardness:
not specified
Test temperature:
24.9 +-0.3°C
pH:
Initial pH: 8.00 (control); between 8.12 and 8.58 (tests)
final pH: 10.74 - 10.76
Dissolved oxygen:
-
Salinity:
not applicable
Nominal and measured concentrations:
96, 1008, and 10,000 mg/L nominal
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type: open
- Material, size, headspace, fill volume: 50 ml glass cylinders
- Aeration:
- Renewal rate of test solution (frequency/flow rate): none
- Initial cells density: approx. 8 x10^4/ml
- Control end cells density: 2.83 x10^6/ml
- No. of vessels per concentration (replicates): 5
- No. of vessels per control (replicates): 7 (algal growth control), 3 (TS controls without algae)


GROWTH MEDIUM
- Standard medium used: yes


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: synthetic medium from ultrapure water
- Total organic carbon: no data
- Alkalinity: not specified
- Ca/Mg ratio: not specified
- Conductivity: not specified



OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: approx. 8000 lux [>= 120 µE/(m2*sec)]


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: spectrophotometer at 578 nm after 24, 48, and 72 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10
Reference substance (positive control):
not specified

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
NOELR
Effect conc.:
10 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: biomass and growth rate
Remarks on result:
other: NOELR = No-observed effective loading rate
Duration:
72 h
Dose descriptor:
EL50
Effect conc.:
> 10 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: biomass and growth rate
Details on results:
- Exponential growth in the control (for algal test): yes,
After 72 h, an increase in biomass (cell numbers) at a factor of >30 was achieved at any concentration.

- Observation of abnormalities (for algal test): no particular findings specified

- Any stimulation of growth found in any treatment: slight stimulation rather than inhibition observed
Results with reference substance (positive control):
not applicable
Reported statistics and error estimates:
not applicable

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the test conditions, the test substance exhibited no acute and chronic toxic effect towards the test system (Scenedesmus subspicatus CHODAT).