trisodium 2-(2-sulfoethoxy)ethane-1-sulfonate ethenesulfonate

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

Study period:

November 2022

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Specific details on test material used for the study:

Reaction mass of disodium 2,2 oxydiethanesulfonate and sodium ethenesulfonate
Batch lot number:202206140027
Dry weight content : 33.94 %, correction factor is 2.94 The test item is a multi-constituent
Composition.
Constituent1:Sodium ethylene sulphonate cas 3039-83-6: 74.84 %
Constituent 2 : Isethionate bisether, disodium salt cas 63440-92-6: 15.18%
Impurity 1:Isethionate sodium cas 1562-00-1: 5.15%
Impurity 2:Sodium ethionate, disodium salt cas1562-03-4: 0.48 %
Impurity 3:Sodium sulfate cas 7757-82-6 :3.12 %
Impurity 4:Sodium ethandisulfonate disodium salt cas 5325-43-9:0.49 %

Analytical monitoring:

yes

Details on sampling:

Samples for possible analysis were taken from all test concentrations and the control according to the schedule below. The method of analysis is described in the appended Analytical Report (Appendix 4).
Frequency at t=0, t=24 and t=72 hours.
Volume 1.5 mL from the approximate center of the test solutions.
Storage Samples were stored in a freezer (set to maintain -20°C) until analysis at the analytical laboratory of the Test Facility.
At the end of the exposure period, the replicates with algae were pooled at each concentration before sampling.
Compliance with the quality criteria regarding maintenance of actual concentrations was checked by running a test vessel at 32 mg/L but without algae (abiotic control) and samples for analysis were taken at the start, after 24 hours of exposure and at the end of the test period.
Additionally, reserve samples of 1.5 mL were taken from all test solutions for possible analysis.

Vehicle:

yes

Remarks:

water

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
- Eluate:
- Differential loading:
- Controls:
- Chemical name of vehicle (organic solvent, emulsifier or dispersant):
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)):
- Test concentration separation factor:
- Evidence of undissolved material (e.g. precipitate, surface film, etc.):
- Other relevant information:

Test organisms (species):

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

Details on test organisms:

Raphidocelis subcapitata, strain: NIVA CHL 1

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

Samples for analysis were taken from all test concentrations and the control according to the schedule below. Frequency at t=0, t=24 and t=72 hours.

Post exposure observation period:

not applicable

Hardness:

24 mg/L CaCO3 (ca +Mg)

Test temperature:

Continuously monitored in a temperature control vessel.
During the exposure period the temperature measured in the incubator was maintained around 22°C. Temperature remained within the limits prescribed by the study plan (21 24°C, constant within ±1°C).

pH:

see table 5

Dissolved oxygen:

not applicable

Nominal and measured concentrations:

Nominal 10, 18, 32, 56 and 100 mg/L.
Control:Test medium without test material or other additives.
Based on the analytical results the effect parameters were expressed as analytically confirmed nominal concentrations.

Details on test conditions:

TEST SYSTEM
- Test vessel:100 mL, all-glass with aluminum caps, perforated for ventilation, containing 50 mL of test solution.
- Type (delete if not applicable): open / closed
- Material, size, headspace, fill volume: 100ml containing 50 ml
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): static
- Renewal rate of test solution (frequency/flow rate):
- Initial cells density: An initial cell density of 1 x 10000 cells/mL.
- Control end cells density:
- No. of organisms per vessel:
- No. of vessels per concentration (replicates):3
- No. of vessels per control (replicates):6
- No. of vessels per vehicle control (replicates):

GROWTH MEDIUM
- Standard medium used: yes M2
- Detailed composition if non-standard medium was used:

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
- Total organic carbon:
- Particulate matter:
- Metals:
- Pesticides:
- Chlorine:
- Alkalinity:
- Ca/mg ratio:
- Conductivity:
- Culture medium different from test medium:M1
- Intervals of water quality measurement:

OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH:
- Photoperiod:
- Light intensity and quality:60 to 120 µE/m²/s
- Salinity (for marine algae):

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: spectrophotometric measurement of samples at 680 nm using a spectrophotometer with immersion probe (path length = 20 mm). Test medium was used as blank.
- Chlorophyll measurement: no
- Other:

TEST CONCENTRATIONS
- Spacing factor for test concentrations:
- Justification for using less concentrations than requested by guideline:
- Range finding study ( see appendix 5)
- Test concentrations: 0, 1, 10, 100 mg/L
- Results used to determine the conditions for the definitive study: yes

CULTURING APPARATUS
-Details on culturing apparatus used:

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: no effects seen

Remarks on result:

other: not mesurable because of the absence of any effect

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: no efects

Remarks on result:

other: not measurable becauce of absence of any effect

Details on results:

For determination of the NOEC(Appendix 2,3) the approaches recommended in the OECD guideline 201 were used. An effect was considered to be significant if statistical analysis of the data obtained for the test concentrations compared with those obtained in the control revealed significant inhibition of growth rate or inhibition of yield (Williams Multiple Sequential t-test Procedure, α=0.05, one-sided, smaller). This statistical comparison was preceded by a check on normal distribution of the data (Shapiro-Wilk’s Test) and a test for homogeneity of the variances (Levene’s test).
The ECx-values could not be determined because the observed effects were below 10%.
ToxRat Professional v 3.3.0 (ToxRat Solutions® GmbH, Germany) was used to perform the analysis.

Results with reference substance (positive control):

Test Facility Study No. 20415601
Experiment performed November 2022.
The batch of Raphidocelis subcapitata tested, showed expected sensitivity to Potassium dichromate (EC50: 1.8 mg/L with a 95% confidence interval ranging from 1.6 to 2.0 mg/L). This value was slightly above the range specified in ISO International Standard 8692, February 2012, i.e. above a range of 0.92 and 1.46 mg/L.
However, based on historical data that were collected at the Test Facility of the past five years, the 72h-ERC50 fell within the expected range of 0.86 to 2.0 mg/L. In conclusion, the batch of Raphidocelis subcapitata tested, showed expected sensitivity to Potassium dichromate.
The raw data from this study are kept in the Charles River Den Bosch archives. The test described above was performed non-GLP.

Validity criteria fulfilled:

yes

Remarks:

for further information see executive Summary.

Conclusions:

In conclusion, under the conditions of the present study with Raphidocelis subcapitata, no inhibition of growth rate or inhibition of yield was recorded at any of the concentrations of Reaction mass of disodium 2,2’-oxydiethanesulfonate and sodium ethenesulfonate (EC 700-978-5) tested.
The 72h-EC50 for growth rate inhibition (ERC50) and for yield inhibition (EYC50) were beyond the range tested.
The 72h-NOEC for growth rate inhibition and for yield inhibition were higher than or equal to 100 mg/L.

Executive summary:

The objective of the study was to evaluate Reaction mass of disodium 2,2’‑oxydiethanesulfonate and sodium ethenesulfonate( EC700-978-5) for its ability to generate toxic effects in Raphidocelis subcapitata during an exposure period of 72 hours and, if possible, to determine the NOEC, EC₁₀, EC₂₀ and EC₅₀ for both inhibition of growth rate and inhibition of yield.

A correction was made for the water content of the test material. A correction factor of 2.946 was used. All concentrations reported are based on dry residue.

Dose Range  Finder ( Appendix 5)

Prior to the start of the main study with the present test material, a non-GLP pre-testing was performed at 0,1,10 and 100 mg/L, to select the most appropriate preparation procedure for test solutions and to provide initial information about the approximate toxic effects in Raphidocelis subcapitata..it was concluded that no inhibition of growth rate or inhibition of yield was recorded at any of the concentrations of Reaction mass of disodium 2,2’-oxydiethanesulfonate and sodium ethenesulfonate (EC 700-978-5) tested.

Final study

A final test at 10,18,32,56,and 100 mg/L was performed, based on the results of a non-GLP preliminary range-finding test performed under a separate project, namely Test Facility Refence No. 20332244.The final  study met the validity criteria prescribed by the study plan and was considered valid.

Validation criteria.

1. In the control, cell density increased by an average factor of at least 16 within the exposure period (i.e. 251).


2. The mean coefficient of variation for section-by-section specific growth rates in the control cultures did not exceed 35% (i.e. 30%).


3. The coefficient of variation of average specific growth rates during the whole test period in replicate control cultures did not exceed 7% (i.e. 0.40%).

 

The results of analysis of the samples taken during the final test are described in Table 3 and Table 4 of the appended Analytical report.                                                                                                                  Samples taken from all test concentrations and the control were analyzed for the two monitored constituents of the test material. The measured concentrations at the start of the test were generally around nominal at all test concentrations for both constituents. During the exposure period, the concentrations remained stable at the end of the test.                                                                                                                       Based on these results, effect parameters were expressed as analytically confirmed nominal concentrations.                                                                                                                               The concentrations measured in the samples taken from solutions with algae were comparable with the concentrations measured in the samples without algae. Hence, it can be stated that the presence of the algae did not affect the concentration of the test material in test medium throughout the test.

For determination of the NOEC the approaches recommended in the OECD guideline 201 were used. An effect was considered to be significant if statistical analysis of the data obtained for the test concentrations compared with those obtained in the control revealed significant inhibition of growth rate or inhibition of yield (Williams Multiple Sequential t-test Procedure, α=0.05, one-

sided, smaller). This statistical comparison was preceded by a check on normal distribution of the data (Shapiro-Wilk’s Test) and a test for homogeneity of the variances (Levene’s test).

The EC_x-values could not be determined because the observed effects were below 10%.

ToxRat Professional v 3.3.0 (ToxRat Solutions^® GmbH, Germany) was used to perform the analysis.No significant differences were recorded between the values for growth rate or yield at any of the test concentrations when compared to the control group.Microscopic observations at the end of the test revealed a normal and healthy appearance of the algal cells exposed to the highest concentration when compared to the control.                          In conclusion, under the conditions of the present study with Raphidocelis subcapitata, no inhibition of growth rate or inhibition of yield was recorded at any of the concentrations of Reaction mass of disodium 2,2’-oxydiethanesulfonate and sodium ethenesulfonate (EC 700-978-5) tested.

The 72h-EC₅₀ for growth rate inhibition (E_RC₅₀) and for yield inhibition (E_YC₅₀) were beyond the range tested.The 72h-NOEC for growth rate inhibition and for yield inhibition were higher than or equal to 100 mg/L.

Description of key information

In conclusion, under the conditions of the present study with Raphidocelis subcapitata, no inhibition of growth rate or inhibition of yield was recorded at any of the concentrations of Reaction mass of disodium 2,2’-oxydiethanesulfonate and sodium ethenesulfonate (EC 700-978-5) tested.
The 72h-EC50 for growth rate inhibition (ERC50) and for yield inhibition (EYC50) were beyond the range tested.
The 72h-NOEC for growth rate inhibition and for yield inhibition were higher than or equal to 100 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L