Lithium potassium titanium oxide

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:

30/06/2003-14/08/2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study has been performed according to OECD and EC guidelines and according to GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

(1984)

Test guideline 3

Qualifier:

according to guideline

Guideline:

ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Lithium Potassium Titanium Oxide

EC Number:

445-620-6

Cas Number:

39318-30-4

Molecular formula:

Hill Empirical formula: K(0.5-0.7) Li(0.27) Ti(1.73) O(3.8-3.95) CAS Empirical formula: K(0.5-0.7) Li(0.27) Ti(1.73) O(3.8-3.95)

IUPAC Name:

Lithium Potassium Titanium Oxide

Details on test material:

- Name of test material (as cited in study report): TERRACESS L
- Substance type: white powder
- Physical state: solid

- Lot/batch No.: 2D79A
- Expiration date of the lot/batch: 11 April 2004
- Storage condition of test material: At room temperature in the dark

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: During the final test duplicate samples for possible analysis were taken from all test concentrations and the control at the start and the end of the test period. Additionally, duplicate samples were taken after 24 hours from the 5 µm filtered solution prepared at 100 mg/l and the control. The volume taken was 20 ml and it was sampled from the approximate centr of the vessels
- Sample storage conditions before analysis: All samples were stored in a deep-freeze until shipment to Solvias AG, Basel, Switzerland

Test solutions

Vehicle:

no

Details on test solutions:

As a consequence of the poor solubility, supersaturated solutions were prepared at nominally 100 mg/l and magnetically stirred for three days to achieve maximum solubility. The resulting dispersions were filtered through a paper filter (Schleicher and Schuell 604) to remove the larger undissolved test substance particles (ca. > 5µm). The filtrate was used to prepare the lower test concentrations. The control received the same treatment. All final solutions were clear and colourless.
In the combined range-finding test dilutions containing 0.1, 1.0 and 10% of the filtrate were tested

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Selenastrum capricornutum
- Strain: NIVA CHL 1
- Source (laboratory, culture collection): In-house laboratory culture
- 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 23 ± 2°C

ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): Pre-culture and test medium: M2. Stock culture medium: M1.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

24 mg CaCO3/L

Test temperature:

22.6°C at the start of the test. During the exposure period the temperature measured in the incubator was maintained between 22.1 and 22.6°C

pH:

8.0-9.5

Nominal and measured concentrations:

Controls: Test medium without test substance or other additives (blank).
A 5 µm filtered solution prepared at a loading rate of 100 mg/l and dilutions containing 10, 18, 32 and 56% of the filtrate.
Analysis of the samples taken from the 5 µm filtrate prepared at a loading rate of 100 mg/l showed that measured concentrations based on Lithium at the start of the test were below the detection limit of the analytical method, i.e. below 0.1 mg/l. Those measured for Titanium equalled 0.1 mg/l in the presence of algae and were below the limit of detection in the absence of algae. The Potassium concentration could be measured and remained stable at approximately 4.5 mg/l during the 72-hour test period. Extrapolating the Potassium concentration to the concentration of the test substance TERRACESS L resulted in a concentration of 20 mg/l (using the formula: K concentration analysed / 0.76*M K )* M TERRACESS L). Extrapolating the measured Titanium concentration (0.1 mg/l) to a concentration TERRACESS L resulted in a concentration of 0.4 mg/l. Hence, actual measured TERRACESS L concentrations can not be determined and are expected to be even lower than indicated above based on the insoluble character of this inert substance

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 ml, all-glass
- Initial cells density: 1 x 10^4 cells/ml
- No. of vessels per concentration (replicates): 3 replicates of each test concentration.
6 replicates of the blank-control.
2 replicates of the highest concentration without algae for sampling purposes.
2 extra replicates of the control and highest concentration for sampling after 24 hours



GROWTH MEDIUM
- Standard medium used: yes


TEST MEDIUM / WATER PARAMETERS
-M2; according to the ISO-Standard "Algal growth inhibition test" Nov. 1989; formulated using Milli-Q water preventing precipitation and with the following composition:
NH4Cl 15 mg/l
MgCl2.6H2O 12 mg/l
CaCl2.2H2O 18 mg/l
MgSO4.7H2O 15 mg/l
KH2PO4 1.6 mg/l
FeCl3.6H2O 80 µg/l
Na2EDTA.2H2O100 µg/l
H3BO3 185 µg/l
MnCl2.4H2O 415 µg/l
ZnCl2 3 µg/l
CoCl2.6H2O 1.5 µg/l
CuCl2.2H2O 0.01 µg/l
Na2MoO4.2H2O 7 µg/l
NaHCO3 50 mg/l
Hardness (Ca+Mg) 0.24 mmol/l (24 mg CaCO3/l)
pH 8.3 ± 0.2



OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: Continuously using TLD-lamps of the type ‘Cool-white’ of 30 Watt, with a light intensity within the range of 70 to 95 uE.m-2.s-1



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]: At the beginning of the test, cells were counted by microscope, using a counting chamber. Thereafter cell densities were determined by spectrophotometric measurement of samples at 720 nm using a Varian Cary 50 single beam spectrophotometer with immersion probe (pathlength =20 mm). Algal medium was used as blank.


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Range finding study: yes
- Test concentrations: Algae were exposed to a blank-control and a 5 µm filtered solution prepared at a loading rate of 100 mg/l in the limit test. In the combined range-finding test dilutions containing 0.1, 1.0 and 10% of the filtrate were tested
- Results used to determine the conditions for the definitive study: no significant algal growth inhibition was observed at 10% of the filtrate and lower. The mean growth rate reduction and cell growth inhibition at 100 % filtrate were 17%. and 50%, respectively. Therefore, the results showed that the EC50 for cell growth inhibition was close to or just below a 5 µm filtered solution prepared at 100 mg/l. The EC50 for growth rate reduction was above the maximum soluble concentration present in the filtered solution

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 4.5 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

potassium

Basis for effect:

growth rate

Remarks on result:

other: (> WSL)

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 26 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks:

Terracess L

Basis for effect:

growth rate

Remarks on result:

other: (>WSL)

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 6.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks:

Terracess L

Basis for effect:

growth rate

Remarks on result:

other: (> WSL)

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 3.6 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Remarks:

Terracess L

Basis for effect:

biomass

Remarks on result:

other: (> WSL)

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no

Results with reference substance (positive control):

- Results with reference substance valid? yes
The EC50 for cell growth inhibition (EBC50: 0-72h) was 0.59 mg/l with a 95 % confidence interval ranging from 0.38 to 0.92 mg/l. The ISO-Standard gives a range for the EC50 for cell growth inhibition from 0.20 to 0.75 mg/l based on 16 inter-laboratory tests. Hence, the EBC50: 0-72h for the present batch was within this range.

The EC50 for growth rate reduction (ERC50: 0-72h) was 0.89 mg/l with a 95 % confidence interval ranging from 0.56 to 1.4 mg/l. The ISO-Standard gives a range for the EC50 for cell growth inhibition from 0.60 to 1.03 mg/l based on 16 inter-laboratory tests. Hence, the ERC50: 0-72h for the present batch was within this range

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study with Selenastrum capricornutum exposed to TERRACESS L, the ErC50 was calculated to be > WSL.