Sodium 3-(2-propyn-1-yloxy)-1-propanesulfonate

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:

2018-10-15 - 2018-10-18 (experimental phase)

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

under GLP

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)

Version / remarks:

OECD Guideline for the Testing of Chemicals No. 201, adopted 23. Mar. 2006, Annex 5 corrected: 28 July 2011 “Freshwater Alga and Cyanobacteria, Growth Inhibition Test”

Deviations:

yes

Remarks:

but not affecting the validity or integrity of the study

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

Commission Regulation (EU) No. 2016/266 amending Regulation (EC) No. 440/2008, Annex IV, Method C.3: “FRESHWATER ALGAE AND CYANOBACTERIA, GROWTH INHIBITION TEST,” adopted 07. December 2015

Deviations:

yes

Remarks:

but not affecting the validity or integrity of the study

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Sodium 3-(2-propyn-1-yloxy)-1-propanesulfonate

EC Number:

608-454-7

Cas Number:

30290-53-0

Molecular formula:

C6H9O4NaS

IUPAC Name:

Sodium 3-(2-propyn-1-yloxy)-1-propanesulfonate

Test material form:

liquid

Specific details on test material used for the study:

The test item was stored in the test facility in a closed vessel at room temperature (20 ± 5°C).

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0 / 10 / 18 / 32 / 56 / 100 mg/L nominal concentration
- Sample storage conditions before analysis: no

Test solutions

Vehicle:

no

Remarks:

test medium was used

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
A stock solution containing 100.0 mg/L test item in algal medium (demineralised water enriched with minerals but without algae) was prepared. Lower test concentrations were prepared by dilution of the stock solution in algal medium.
- Controls: algal medium / potassium dichromate
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): none

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Unicellular freshwater green alga
- Strain: Desmodesmus subspicatus, SAG Strain Number 86.81
- Source (laboratory, culture collection): The culture of Desmodesmus subspicatus was obtained in January 2016 by MBM Sci-encebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen). The algae are kept as stock culture on solid agar at 2 - 8 °C. From the stock culture, a permanent culture was prepared. From an aliquot of the permanent culture, the pre-culture was prepared.
- Age of inoculum (at test initiation): For the pre-culture an aliquot of the permanent culture was brought into nutrient medium and incubated under continuous lighting for 96 hours under test conditions. The resulting culture grew exponentially.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

none

Test conditions

Test temperature:

22.8 – 24.0 °C

pH:

7.5 - 8.9

Nominal and measured concentrations:

Nominal: 0 / 10 / 18 / 32 / 56 / 100 mg/L
Measured, t=0h: n.d. / 10.1 / 17.8 / 32.3 / 55.9 / 100.7 mg/L
Measured, t=72h: n.d. / 10.1 / 18.1 / 32.6 / 57.0 / 104.2 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass flasks
- Type (delete if not applicable): open, covered with perforated plastic foil acting as a stopper
- Material, size, headspace, fill volume: glass flasks total volume 65 mL, filled with 45 ±1 mL
- Renewal rate of test solution (frequency/flow rate): none
- Initial cells density: 2300 cells/mL
- Control end cells density: 522263 cells/mL
- No. of vessels per concentration (replicates): 3 replicates for each treatment
- No. of vessels per control (replicates): 6 replicates for the blank control
- No. of vessels per vehicle control (replicates): n/a

GROWTH MEDIUM
- Standard medium used: Yes, the algal medium corresponds to the OECD TG 201 medium.

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: 5000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter
- Other: pH; appearance of the algae

TEST CONCENTRATIONS
The concentrations to be tested are based on non GLP pre-tests.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a separate reference test.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

yield

Effect concentrations 3

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

yield

Effect concentrations 5

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 6

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

yield

Effect concentrations 7

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 8

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

yield

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): none
- Any stimulation of growth found in any treatment: yes, but not dose-dependent
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: none

Results with reference substance (positive control):

- Results with reference substance valid? yes
Parameter Value 95% confidence interval
72h ErC50 0.79 mg/L 0.79 mg/L – 0.79 mg/L
72h EyC50 0.39 mg/L 0.35 mg/L – 0.45 mg/L

Reported statistics and error estimates:

Since no inhibition of algal growth has occurred, no statistical evaluation was performed.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The study was conducted under GLP according to OECD guideline 201 and EU method C.3 on the registered substance itself. The method is to be considered scientifically reasonable with no deficiencies in documentation or relevant deviations from the guidelines, the validity criteria were met. Positive and negative controls gave the appropriate response. Hence, the results can be considered as reliable to assess the toxicity of POPS-Na towards algae.
At the start and at the end of the test, the content of the test item in the test solutions was determined using HPLC.
The measured concentrations lay between 99 % and 101 % of the nominal concentrations at the beginning of the test and between 100 % and 104 % of the nominal concentrations at the end of the test. Therefore, the determination of the results was based on the nominal concentrations.
No inhibition of algal growth has occurred, the 72h NOEC was so determined to be ≥ 100 mg/L, the EC50 > 100 mg/L. Hence, POPS-Na does not need to be classified as hazardous to the environment according to Regulation 1272/2008 and amendments, neither acute nor chronic.

Executive summary:

The study was conducted under GLP according to OECD guideline 201 and EU method C.3 on the registered substance itself. One valid experiment was performed.

The study was performed using 5 concentrations ranging from 10 to 100 mg/L. Incubation time (test system Desmodesmus subspicatus) was 72 hours. The cell concentration of each replicate was determined by measuring the cell numbers every 24 hours with an electronic particle counter. Growth rate µ and the yield were determined from the cell number at the respective observation times.

No inhibition of algal growth was observed in all tested concentrations.Algal growth in the highest concentration was higher than in the control.

At the start and at the end of the test, the content of the test item in the test solutions was determined using HPLC.

The measured concentrations lay between 99 % and 101 % of the nominal concentrations at the beginning of the test and between 100 % and 104 % of the nominal concentrations at the end of the test. Therefore, the determination of the results was based on the nominal concentrations.

Since no inhibition of algal growth has occurred, no statistical evaluation was performed.

The 72h-EC₅₀values of potassium dichromate (K₂Cr₂O₇, CAS No. 7778-50-9) were determined in a separate reference test. The values lay within the range of the laboratory (growth rate 0.73 - 1.10 mg/L, yield 0.21 – 0.66 mg/L).

The following results for the test item Propargyl 3-sulfopropyl ether, sodium salt (POPS-Na) were determined:

 

Table Results of the test item

Endpoint	NOEC	LOEC	EC10	EC50
Growth Rate	≥ 100 mg/L	> 100 mg/L	> 100 mg/L	> 100 mg/L
Yield	≥ 100 mg/L	> 100 mg/L	> 100 mg/L	> 100 mg/L

 

POPS-Na does not need to be classified as hazardous to the environment according to Regulation 1272/2008 and amendments, neither acute nor chronic.