Sodium methyl sulphate

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:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Sodium methyl sulphate

EC Number:

208-142-7

EC Name:

Sodium methyl sulphate

Cas Number:

512-42-5

Molecular formula:

CH4O4S.Na

IUPAC Name:

sodium methyl sulphate

Test material form:

solid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: KIRSCHAZ2-00182
- Expiration date of the lot/batch: 2018-07-07
- Water solubility: 925 g/L ± 9 g/L at T = 20.0 °C ± 0.5 °C

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature, protect from light, in the tightly closed original
container
- Stability under test conditions: stable

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: One limit concentration of 120 mg/L
- Sample storage conditions before analysis: All original samples were stored at room temperature. Prepared samples were stored at room temperature in an autosampler until analysis.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
120 mg test item/L was freshly prepared with dilution water. The dispersion was agitated until the stock solution was clear. Before use the completeness of dissolution was checked
via Laser beam (Tyndall effect), which was negative.

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriel/a subcapitata HINDAK, SAG 61.81
- Source (laboratory, culture collection): Sammlung von Algenkulturen (SAG) Pflanzenphysiologisches Institut der Universität Göttingen, D-37073 Göttingen
- Cultivation at test facility: Fresh stocks are prepared every month on Z-Agar. Light intensity amounted to 2590 - 5180 lux for 24 hours per day.
- Age of inoculum (at test initiation): A three day old preculture, prepared in dilution water, was used as inoculum

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

21.8 -23.0 °C

pH:

7.86-8.50

Nominal and measured concentrations:

Nominal: 120 mg/L, measured: 130-142 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Sterile Erlenmeyer flasks,
- Type (delete if not applicable): sealed with cotton wool plugs
- Material, size, headspace, fill volume: 250 mL
- Initial cells density: 6839 cells/mL
- Control end cells density: 1926568 cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to the guideline

OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Photoperiod: 24 hours/day light
- Light intensity and quality: 4630 to 5602 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]
- Chlorophyll measurement: Cell density was measured daily via Chlorophyll a-fluorescence, excitation at 436 nm, emission at 685 nm. Dilution water was used as a background signal. No self-fluorescence was found in the
definitive test at the concentration of 120 mg/L.
- Other: Microscopic evaluation of the cells at the start and end of the exposure was carried out. The cells were checked for unusual cell shapes, colour differences, differences in chloroplast morphology,
flocculation, adherence of algae to test containers and aggregation of algae cells.

TEST CONCENTRATIONS
-One limit concentration of 120 mg/L was tested. The concentration level is based on the results of a preliminary range finding test (non-GLP).

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 120 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.:

>= 120 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

- Results with reference substance:
- ErC50: 0.435 mg/L
:

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In this study, no inhibition of the growth rate but a slight effect on yield (16% inhibition in comparison with the control) of the freshwater green alga Pseudokirchneriella subcapitata was found after 72 hours exposure to the test item Sodium methyl sulfate. The nominal EC50-values for inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were > 120 mg test item/L, respectively. The nominal NOEC-value for inhibition of growth rate was 120 mg test item/L. The NOEC-value for yield was < 120 mg test item/L. All effect values given are based on nominal test item concentration of Sodium methyl sulfate.