Sodium 1,2-diisobutoxycarbonylethanesulphonate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2011

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all
- Sampling method and Sample storage conditions before analysis: Specimens were diluted with me
thanol (1:1) and were stored deep frozen (≤ -18°C) until they were analysed. Concentrations of the
test item in test solutions were analysed at test start (0 hours) and at the test end (48 hours).

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
A stock solution was prepared by adding the test item to test medium. The stock solution was stirred for 10 minutes on a magnetic stirrer.
Stock solution and test vessels were prepared in the following way:

- a stock solution (stock A) was prepared by weighing 2193.0 mg test item into a graduated flask and bringing to a volume of 1000 mL (= 2193.0 mg/L test item)
- 0.5 mL algal inoculum (measured 100 x 104 cells/mL in the stock culture) were added to a 100 mL test volume to result in an initial biomass of 5 x 103 cells/mL

- Controls: blank control

- Chemical name of vehicle (organic solvent, emulsifier or dispersant): none

- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)): not relevant

- Test concentration separation factor: 2.5

- Evidence of undissolved material (e.g. precipitate, surface film, etc.): no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Desmodesmus subspicatus HILSE
- Strain: strain: 86.81 SAG
- Source (laboratory, culture collection): purchased from
MBM ScienceBridge GmbH,
Hans-Adolf-Krebs-Weg 1, 37077 Göttingen
Germany

- Age of inoculum (at test initiation): 4 days
- Method of cultivation: cultivation was performed in glass flasks with the medium described above; algae were kept at the same temperature and light conditions as in the test itself

ACCLIMATION
- Acclimation period: 4 days
- Culturing media and conditions (same as test or not): yes

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

22.7 – 23.2 °C (recorded continuously in a vessel containing test medium)

pH:

7.44 to 8.09

Nominal and measured concentrations:

Control (0), 51.6, 140.4, 350.9, 877.2, 2193.0 mg/L test item; Control (0), 23.0, 57.5, 143.9, 359.7, 899.1 mg/L active matter
Measured concenrations within 100 to 108 % of the nominal concentrations.

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL Erlenmeyer flask with air-permeable stoppers
- Type (delete if not applicable): air-permeable stoppers
- Initial cells density: 5000 cells/mL
- Control end cells density: 349000 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used: AAP medium


OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: continuous cold white fluorescent light; light intensity was measured once before test start: light intensity: on average 75 µE·m-2·s-1 measured at 400-700 nm differences from the selected light intensity over the test area did not exceed the range ± 15%

EFFECT PARAMETERS MEASURED:
- Determination of cell concentrations: 24, 48 and 72 hours after test start, the biomass (number of cells per millilitre) in all test vessels including control was determined by direct counting (actual microscopic cell count using a Neubauer counting chamber).
- Chlorophyll measurement: no

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.5
- Justification for using less concentrations than requested by guideline: N.A.


CULTURING APPARATUS
-Details on culturing apparatus used: axenic stock cultures grew in culturing vessels for 4 days prior to test initiation; cultivation was performed in glass flasks with the medium described above; algae were kept at the same temperature and light conditions as in the test itself

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 899.1 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 899.1 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): none
- Unusual cell shape: none
- Colour differences: none
- Flocculation: none
- Adherence to test vessels: none
- Aggregation of algal cells: none
- Other: No differences such as sedimentation of test solution, cell aggregation or colour differences of algae cells were noticed between the control vessels and the test vessels containing the test item during the test.
- Any stimulation of growth found in any treatment: yes, but < 5% at any dose level
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no, no relevant difference observed
- Effect concentrations exceeding solubility of substance in test medium: no

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50: 1.11 mg/L

Reported statistics and error estimates:

From average specific growth rates and yield, recorded in a series of test solutions, effect concentrations of ErC10, ErC20 and ErC50, (average specific growth rate) and EyC10, EyC20 and EyC50 (yield) was determined using concentrations-response modelling (linear regression method, Probit).

Validity criteria fulfilled:

yes

Conclusions:

72h-ErC10: > 899.1 mg a.i./L
72h-ErC50: > 899.1 mg a.i./L

Executive summary:

In the Klimisch 1 GLP study from Warning (2021) the toxicity of the registered substance to Desmodesmus subspicatus was determined in a static 72 -Hour Algal Growth Inhibition Test. The test was performed according to OECD 201. The nominal test concentrations were 0 (control), 23.0, 57.5, 143.9, 359.7, 899.1 mg active matter/L. Six control replicates and 3 replicates from each test solution were set up. Dose verification analysis was performed and confirmed the correct dosage and stability of the test item throughout the test period for all test groups. In order to determine the growth of the cultures, the cells were counted by Neubauer counting chamber. The cell density was determined at 0, 24, 48 and 72 hours. The growth of the control cultures fulfilled the validity criteria from OECD 201 (2006). The 72 -hour ErC10 and ErC50 are both > 899.1 mg active matter/L based on the nominal concentration.

 

The results of this study are considered to be reliable without restrictions for the risk assessment.

Description of key information

72 h ErC10 > 899.1 mg/L
72 h ErC50 > 899.1 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:

899.1 mg/L

EC10 or NOEC for freshwater algae:

899.1 mg/L

Additional information

In the Klimisch 1 GLP study from Warning (2021) the toxicity of the registered substance to Desmodesmus subspicatus was determined in a static 72 -Hour Algal Growth Inhibition Test. The test was performed according to OECD 201. The nominal test concentrations were 0 (control), 23.0, 57.5, 143.9, 359.7, 899.1 mg active matter/L. Six control replicates and 3 replicates from each test solution were set up. Dose verification analysis was performed and confirmed the correct dosage and stability of the test item throughout the test period for all test groups. In order to determine the growth of the cultures, the cells were counted by Neubauer counting chamber. The cell density was determined at 0, 24, 48 and 72 hours. The growth of the control cultures fulfilled the validity criteria from OECD 201 (2006). The 72 -hour ErC10 and ErC50 are both > 899.1 mg active matter/L based on the nominal concentration.

 

The results of this study are considered to be reliable without restrictions for the risk assessment.