Disodium hexatitanate

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

3 January 2012 - 30 March 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:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

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:

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

Test solutions

Vehicle:

yes

Details on test solutions:

Due to the presence of titanium in the composition of the test substance, the test organisms were maintained and the tests conducted in ISO medium, as recommended in the OECD test guideline, to minimise chelation. The medium was prepared in deionised, reverse osmosis water.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Stock cultures of Daphnia magna were maintained in glass vessels containing approximately 0.5 to 0.8 litres of Elendt M4 culture medium in a temperature-controlled laboratory at nominally 20 ± 2 °C. A photoperiod of 16 hours light : 8 hours dark was maintained, with periods of subdued lighting at the beginning and end of each light phase. The culture medium was renewed three times each week. Cultures were fed daily with a suspension of the unicellular green algae, Pseudokirchneriella subcapitata, to provide nominally 0.1 to 0.2 mg carbon per daphnid, per day, except during the initial two days when a slightly lower ration was given. Culture conditions ensure that the stock animals reproduce by parthenogenesis. The day before the start of the study, all juvenile Daphnia were removed from the laboratory cultures. The following morning, juveniles produced by the gravid (egg-bearing) adult Daphnia were removed from the culture vessels and held in a separate holding vessel; these animals, which were less than 24 hours old, were used in the test.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Test temperature:

20 ± 2 °C

Nominal and measured concentrations:

Following investigations into the aqueous solubility of test substance in the formulation trial, the range finding test employed filtrates of aqueous mixtures prepared with initial nominal test concentrations of 1, 10 and 100 mg/L. After 48 hours, no immobility was observed at any test concentration. Analysis of samples of the test media indicated that the levels of titanium were below the limit of detection of the analytical method (0.2 mg/L).
Based on these results, the definitive (limit) test employed a filtrate of an aqueous mixture with an initial nominal concentration of 100 mg test substance.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Effect concentrations 2

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Test substance was not found to be toxic to Daphnia magna in media that was filtered prior to use; therefore the material was tested within its limit of aqueous solubility under the conditions of the test.
Consequently, the 48-hour EC50 could not be calculated but must be >0.1 mg/L and the “noobserved effect concentration” was 0.1 mg/L.