Dipotassium dodecenylsuccinate

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

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

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Dipotassium dodecenylsuccinate

EC Number:

260-612-0

EC Name:

Dipotassium dodecenylsuccinate

Cas Number:

57195-28-5

Molecular formula:

C16H26K2O4*H2O

IUPAC Name:

Dipotassium dodecenylsuccinate

Test material form:

liquid

Details on test material:

30 % aqueous solution
pure substance is solid (bulk/powder), but is only used as aqueous solution and blends it into mixture
Substance dissolves in water at 40wt%, then becomes gel and becomes solid, if mixed 61wt% with water

Specific details on test material used for the study:

- Test item: Dipotassium dodecenylsuccinate (aq. solution)
- Batch number: 170727
- Active substance: Dipotassium dodecenylsuccinate (30% : Water 70%)
- Appearance: Light brownish, clear liquid
- Water solubility: Soluble
- Stability under test conditions: Not specified
- Expiry date: 2019-07-27
- Recommended storage: Store in the tightly closed container in a dark, cool (room temperature), dry and well ventilated place.

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

- Test item: Dipotassium dodecenylsuccinate (aq. solution)
- Stock solution, media preparation: 2000 mg test item/L was freshly prepared with dilution water. The dispersion was agitated until the solution was visually clear. The stock solution was checked via laser beam (Tyndall effect) for undissolved test item. The Tyndall effect was negative.
- Test concentrations (nominal): The stock solution was diluted to get the required test item concentrations. Six concentrations were tested in a geometrical series with a spacing factor of 2.5: 20.5 - 51.2 - 128 - 320 - 800 - 2000 mg/L, corresponding to active substance concentrations of 6.15 – 15.4 – 38.4 – 96 – 240 - 600 mg Dipotassium dodecenylsuccinate/L. The concentrations are based on the results of a preliminary range finding test (non-GLP).
- Control: Six replicates (without test item) were exposed under the same conditions as the test concentrations.
- Reference Item: Potassium dichromate was tested as a reference item.
- Replicates: 3 replicates per concentration level and 6 for the controls were tested.
- Test container: Sterile Erlenmeyer flasks (vol. 250 mL) with cotton wool plugs
- Test volume: 100 mL
- Ultrapure water: Ultrapure water was used to prepare the dilution water (conductivity max. 0.1 µS/cm)

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: Pseudokirchneriella subcapitata HINDÁK CCAP 278/4
- Source (laboratory, culture collection): Culture Collection of Algae and Protozoa (CCAP), SAMS Research Services Ltd., Dunstaffnage Marine Laboratory, Dunbeg, OBAN; Argyll PA37 1QA; Scotland, UK
- Method of cultivation: Fresh stocks are prepared every month on Z-Agar. Light intensity amounts 2567 – 5130 lux for 24 hours per day.
- Culturing media and conditions: Nutrient medium Z according to LÜTTGE et al. (1994)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

21 - 24 °C

pH:

7.24 - 9.23

Nominal and measured concentrations:

nominal concentrations: 20.5, 51.2, 128, 320, 800 and 2000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Sterile Erlenmeyer flasks (vol. 250 mL) with cotton wool plugs
- Type (delete if not applicable): open
- Initial cells density: Nominal: approximately 5 x 103 - 104 cells/mL; Actual: 6442 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: One-fold concentrated modified AAP medium according to the guidelines, modified with regard to the content of MgCl2, MgSO4 and CaCl2 was used. The concentration of these components was reduced in order to enable solubility of the test item in the dilution water.

OTHER TEST CONDITIONS
- Photoperiod: 24 hours/day light
- Light intensity and quality: Approximately 4440 to 8880 lux, corresponding to 60 to 120 µE*m-2*s-1

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 2 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

EC50

Remarks:

yield

Effect conc.:

678 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 3

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

51.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: NOEC-values for both inhibition of growth rate and yield.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In this study, Dipotassium dodecenylsuccinate (aq. solution) was found to inhibit the growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 hours with the following effect values (based on nominal test item concentrations): The EC50-values with 95% confidence intervals for inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were > 2000 mg/L and 678 (467 - 1037) mg/L of the nominal test item concentration, respectively. The NOEC-values for both inhibition of growth rate and yield after 72 hours were 51.2 mg/L of the nominal test item concentration.