Disodium hexatitanate

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:

13 January 2012 - 13 July 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Disodium hexatitanate

EC Number:

815-182-4

Cas Number:

12058-75-2

Molecular formula:

Na2Ti6O13

IUPAC Name:

Disodium hexatitanate

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Identity: Terracess DSR
Chemical name: Sodium Titanium Oxide
Appearance: White powder
Storage conditions: Room temperature
Batch number: 1C96
Expiry date: 24 March 2014
Purity/assay: 100%
Sample received: 26 August 2011

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples were taken from control and test flasks at 24, 48 and 72 hours

Test solutions

Vehicle:

yes

Details on test solutions:

Four stock solutions were prepared according to the following table, using filtered, dechlorinated tap water which had been softened and treated by reverse osmosis, before microfiltration and purification (resistivity of 18 Megohm/cm). Stock solutions were sterilised by autoclaving or by membrane filtration before being stored at 4 °C in the dark.
Aliquots of stock solutions 1-3 were further diluted with the same diluent and autoclaved again to produce the working strength nutrient medium. Stock solution 4 was added to the medium on the day of use. The pH of the medium after equilibration with air is approximately 8.

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

Strain No. CCAP 278/4

Study design

Test type:

not specified

Water media type:

freshwater

Total exposure duration:

72 h

Test conditions

Test temperature:

The temperature was maintained at 23 ± 2°C.

pH:

7.96 - 8.64

Results and discussion

Effect concentrations

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

The 72-hour EC50 values could not be calculated but must be >0.1 mg/L and the “no-observed effect concentration” was 0.1 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

After 72 hours of exposure to a saturated solution, test substance was not found to be inhibitory to Pseudokirchneriella subcapitata under the conditions of the test.
Consequently, the 72-hour EC50 values could not be calculated but must be >0.1 mg/L and the “no-observed effect concentration” was 0.1 mg/L.