Dipotassium titanate(2-)

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:

26 January 2018 till 07 Feb 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

Principles of method if other than guideline:

Procedures for obtaining a saturated solution were based on the test methods described in the OECD series on testing and assessment number 23, 2000.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dipotassium titanate(2-)

EC Number:

261-919-2

EC Name:

Dipotassium titanate(2-)

Cas Number:

59766-31-3

Molecular formula:

K2O17Ti8

IUPAC Name:

dipotassium titanate(2-)

Test material form:

solid: particulate/powder

Details on test material:

Appearance: White powder (fibrous particle)
Test item storage: At room temperature

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples for possible analysis were taken from all test concentrations and the control at t=0 and t=48 hours. In addition, the filter containing the undissolved residue used in the preparation of test solutions was analysed.

Test solutions

Vehicle:

no

Details on test solutions:

The test material was not completely soluble in test medium at the loading rate initially prepared. The water solubility at 20 °C was determined to be ≤ 0.041 mg/L, using the column elution method (Charles River Den Bosch Project 518459).
Preparation of test solutions started with a loading rate of 100 mg/L applying a three-day period of magnetic stirring to ensure maximum dissolution of the test item in test medium. Thereafter, the aqueous Saturated Solution (SS) was collected by filtration and used as the highest test concentration. Lower test concentrations (1% and 10% of the SS) were prepared by subsequent dilutions of the SS in test medium. All test solutions were clear and colorless at the end of the preparation procedure. Hence tested concentrations were TISMO D Solutions containing 1.0, 10 and 100% of a Saturated Solution prepared at a loading rate of 100 mg/L. As controls test medium without test item or other additives was used.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by a cyclical parthenogenesis under specified breeding conditions.
Source: In-house laboratory culture with a known history.
Validity of batch: Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.
Characteristics: For the test selection of young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.
Feeding during test: none.

Study design

Test type:

static

Water media type:

other: Adjusted ISO medium

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

Not applicable.

Test conditions

Hardness:

180 mg/L expressed as CaCO3

Test temperature:

20-21°C

pH:

Range at start and end in control and all test concentrations: 7.9-8.1

Dissolved oxygen:

Range at start and end in control and all test concentrations: 8.6-9.3 mg/L

Salinity:

Not applicable.

Conductivity:

Not measured.

Nominal and measured concentrations:

Nominal concentrations were TISMO D Solutions containing 1.0, 10 and 100% of a Saturated Solution prepared at a loading rate of 100 mg/L. No test item was detected in the control samples and test samples (100% of a Saturated Solution). To demonstrate proper preparation of the test solutions, an aliquot of the filter residue was analyzed. The element Titanium was detected in this solution, which demonstrated that the test item was used for the preparation of the test solutions. Based on these results, the effect parameters were based on the applied loading rate.

Details on test conditions:

Test vessels: 60 mL, all-glass;
Number of daphnids: 20 each in the control and the highest test concentration, 10 per intermediate test concentration;
Loading: 5 per vessel containing 50 mL of test solution;
Light: 16 hours photoperiod daily;
Feeding: No feeding;
Aeration: No aeration of the test solutions;
Introduction of daphnids: Within 18 minutes after preparation of the test solutions.
Immobility (including mortality): Recorde at 24 hours and at 48 hours.
Dissolved oxygen & pH: Measured at the beginning of the test, for all concentrations and the control. At the end of the test, for the highest concentration and the control.
Temperature of medium: Measured continuously in a temperature control vessel, beginning at the start of the test.

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: see remark

Remarks:

Tested concentrations were TISMO D Solutions containing 1.0, 10 and 100% of a Saturated Solution prepared at a loading rate of 100 mg/L. The effect parameters were based on the applied loading rate of 100 mg/L.

Basis for effect:

mobility

Details on results:

In the control and in the TISMO D Solutions containing 1.0, 10 and 100% of a Saturated Solution prepared at a loading rate of 100 mg/L, 0% immobility was recorded after 24 and 48 hours. .

Results with reference substance (positive control):

Potassium dichromate (K2Cr2O7) was tested in a separate test on 02-04 January 2018. The 24h-EC50 was 0.87 mg/L with a 95% confidence interval between 0.80 and 0.95 mg/L. This is within the expected range according to OECD 202 (2012): 06-2.1 mg/L, confirming the sensitivity of the test organisms.

Reported statistics and error estimates:

Not applicable.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

1. In the control: 0% immobility, no signs of disease or stress. 2. The oxygen concentration at the end of the test was ≥3 mg/L in control and test vessels.

Conclusions:

Under the conditions of the present study with Daphnia magna, no immobilisation was recorded at the maximum soluble concentration of TISMO D in test medium at a loading rate of 100 mg/L. The 48h EL50 for Daphnia magna exposed to TISMO D was beyond the range tested, i.e. exceeded a loading rate of 100 mg/L.

Executive summary:

The objective of the study was to evaluate TISMO D for its ability to generate acute toxic effects on the mobility of Daphnia magna during an exposure period of 48 hours and, if possible, to determine the EL50 at 24 and 48 hours of exposure.

The study procedures described in this report were based on the OECD guideline No. 202, 2004. In addition, procedures were based on the test methods described in the OECD series on testing and assessment number 23, 2000.

The batch of TISMO D tested was a white powder (fibrous particle) with a purity of 99.7% and not completely soluble in test medium at the loading rate initially prepared.

A Saturated Solution (SS) was prepared at a loading rate of 100 mg/L and used as the highest concentration. Lower concentrations were prepared by diluting the highest concentration in test medium.

A combined limit/range-finding test was performed. Twenty daphnids per group (5 per replicate, quadruplicate) were exposed to an untreated control and to an undiluted SS prepared at a loading rate of 100 mg/L, in a limit test. In addition ten daphnids per group (5 per replicate, duplicate) were exposed to solutions containing 1.0 and 10% of the SS prepared at a loading rate of 100 mg TISMO D per litre in the combined range-finding test. The total exposure period was 48 hours and samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the test.

No immobilisation was observed at any of the loading rates tested.

Samples taken from the control and the highest test concentration were analysed. No test item could be detected. Consequently the undissolved residue collected in the filter used in the preparation of test solutions was analysed. This analysis proved that the residue was test item related and the test solutions had been prepared correctly. Based on these results, the effect parameters were based on the applied loading rate.

The study met the acceptability criteria prescribed by the study plan and was considered valid.

In conclusion, due to the very low solubility of TISMO D in test medium, concentration levels that might be toxic for D. magna could not be reached. Under the conditions of the present study with D. magna, no immobilisation was recorded at the maximum soluble concentration of TISMO D in test medium at a loading rate of 100 mg/L. The 48h EL50 for Daphnia magna exposed to TISMO D was beyond the range tested, i.e. exceeded a loading rate of 100 mg/L.