Lithium 2-aminobenzothiazole-6-sulphonate

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:

2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Lithium 2-aminobenzothiazole-6-sulphonate

EC Number:

265-367-3

EC Name:

Lithium 2-aminobenzothiazole-6-sulphonate

Cas Number:

65072-36-8

Molecular formula:

C7H6N2O3S2.Li

IUPAC Name:

lithium 2-amino-1,3-benzothiazole-6-sulfonate

Test material form:

solid: particulate/powder

Details on test material:

- Bulk Density (g/ml): 0.39
- Particle size distribution (μm): 19.6
- Water solubility: 20%

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: IR2510181
- Expiration date of the lot/batch: 25 October 2019
- Purity test date: Not specified

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At controlled room temperature (15 - 25 °C, ≤ 70% RH)
- Stability under test conditions: Not specified
- Solubility and stability of the test substance in the solvent/vehicle: soluble at 100 mg/L in dilution water (ISO medium)

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Dissolved in ISO medium
- Preliminary purification step (if any): Not specified
- Final dilution of a dissolved solid, stock liquid or gel: 100 mg/L (nominal)

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg/L.
- Analytical measurements were performed at the start and end of the test.

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: 61.81 SAG
- Source: SAG - Collection of Algal Cultures, Institute of Plant Physiology, Univ. Göttingen, Germany.
- Age of inoculum: 4 days.

Study design

Test type:

static

Water media type:

other: ISO medium, reconstituted water

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Hardness:

The reconstituted water (ISO medium) had a total hardness of 245 mg/L (as CaCO3).

Test temperature:

Culture temperature was checked at the beginning of the experiment and each day thereafter in a flask filled with water, in the climatic chamber. In addition, water temperature was continuously measured (with a min/max thermometer) within the climate chamber. The temperature was 22.3-22.7°C measured in the flask and 21.0-23.5°C measured within the climate chamber.

pH:

The pH was checked at the beginning and at the end of the test, in the control and each concentration. The pH of the control medium was not increased by more than 1.5 units during the test. The range of the pH was 7.51 – 8.94 during the experiment.

Nominal and measured concentrations:

Nominal concentration: 100 mg/L.
Measured concentration (start of study): 94.9 ± 1.742 mg/L
Measured concentration (end of study): 97.3 ± 0.893 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: glass (Erlenmeyer flask)
- Type: closed
- Volume: 250 mL
- Initial cells density: 10^4 cells/mL
- Test end cells density: 50.83 x 10^4 cells/mL
- Control end cells density: 70.83 x 10^4 cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

Results and discussion

Effect concentrations

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Details on results:

The Test Item had no toxic effects on growth rate, had 27% inhibition effect on the algae biomass and 29% effect on yield at 100 mg/L (nominal); the EC50 results are higher than this level of the Test Item in the test medium.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In a study in Pseudokirchneriella subcapitata, lithium 2-aminobenzothiazole-6-sulphonate was found to have an EC50 > 100 mg/L.

Executive summary:

In an OECD guideline study, conducted to GLP, lithium 2-aminobenzothiazole-6-sulphonate was found to have an EC50 > 100 mg/L in Pseudokirchneriella subcapitata.