4-[4-[[2,5-dimethoxy-4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonic acid, sodium salt

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

May 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Remarks:

Details on analytical measurement, test concentrations and phys-chem data are missing

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

yes

Remarks:

modified to differentiate between toxic effects (algicidal) and indirect effects due to light absorption in coloured test substance (algistatic)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

4-[4-[[2,5-dimethoxy-4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonic acid, sodium salt

EC Number:

263-418-4

EC Name:

4-[4-[[2,5-dimethoxy-4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonic acid, sodium salt

Cas Number:

62121-76-0

Molecular formula:

C20H20N4Na2O12S3

IUPAC Name:

4-[4-[[2,5-dimethoxy-4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonic acid, sodium salt

Test material form:

solid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

At the start of the test a sample from the freshly prepared stock solution and duplicate samples from the freshly prepared test media (without algae) of all test concentrations and from the control were taken. All samples are kept stored at -20 °C to enable additional analyses on request of the sponsor. After delivery of the final test report all samples will be discarded.

Test solutions

Vehicle:

no

Details on test solutions:

A stock solution was prepared just before the start of the test by dissolving the test substance in test water (1.0 g/l).

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Scenedesmus subspicatus
- Strain: 86.81 SAG
- Source (laboratory, culture collection): Sammlung von Algenkulturen, Pflanzenphysiologisches Institut der Universität Göttingen, Germany
- Method of cultivation: in synthetic test water according to OECD guideline 201

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Nominal and measured concentrations:

Me

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: closed (Erlenmeyer flask covered with glass dishes, covered with wath glass dishes
- Material, size, headspace, fill volume: glass, 100 mL, -, 50 mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- Number of organisms: 10000 cells/mL

The test was performed in Erlenmeyer flasks (100 ml), each with 50 ml algal suspension, continuously stirred by magnetic stirrers, 3 flasks per test concentration and 6 flasks in control. Each Erlenmeyer flask was placed in a black cylinder, coated inside with aluminium foil. The cylinders were covered with glass dishes, the dishes were covered with watch glass dishes to prevent evaporation.
The test included two experimental parts:
Experimental part A:
The algae grew in test media with dissolved dyestuff in the Erlenmeyer flasks (5 test concentrations and a control). All glass dishes above the cylinders contained untreated test water. Thus, the inhibition of algal growth in this experimental part was caused due to a real toxic effect of the dyestuff and in addition to the reduced light intensities in the coloured test media in the Erlenmeyer flasks.
Experimental part B:
In this experimental part the glass dishes above the cylinders contained the coloured dyestuff solutions with the same five test concentrations as in Part A, however without algae (3 replicates per test concentration). In the Erlenmeyer flasks below, the algae grew in test water without dyestuff (as in control), however under changed light conditions due to the filter effect of the coloured test solutions in the glass dishes. Thus, the growth inhibition in part B was caused due to light absorption only. The depth of the test solutions in the glass dishes was
20 mm, i.e. half the depth of the test solutions in the Erlenmeyer flasks because the algae in the stirred test solutions stay in the statistical mean in this mean depth.
All flasks were incubated in a temperature controlled water bath and continuously illuminated at a mean light intensity of about 8200 Lux, range 7600 - 8600 Lux. The light intensity was measured just before the start of the test below the coating cylinders in those areas, where the Erlenmeyer flasks were placed in the test. This illumination was achieved by fluorescent tubes (universal white L 25, 36 W) installed above the algal flasks.
The test duration was 72 hours.


TEST MEDIUM / WATER PARAMETERS according to guideline

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

No effect occured up to 10 mg/L. Due to the lack of documentation it is unclear why the test was stopped at this concentration. Therefore, the study will not be used for classification purposes.