Reaction product of: 2-[[4-amino-2-ureidophenylazo]-5-[(2-(sulfooxy)ethyl)sulfonyl]]benzenesulfonic acid with 2,4,6-trifluoropyrimidine and partial hydrolysis to the corresponding vinylsulfonyl derivative,mixed potassium/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:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Yellow MGi 1301

IUPAC Name:

Yellow MGi 1301

Test material form:

solid

Sampling and analysis

Analytical monitoring:

yes

Test organisms

Test organisms (species):

Scenedesmus sp.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

24 °C

pH:

7.5-9.7

Nominal and measured concentrations:

Nominal test concentrations were 1.9, 6.1, 19.5, 62.5 and 200 mg test substance/l

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 200 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.:

> 121 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

19 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

8.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Any other information on results incl. tables

The growth inhibition effect of YELLOW MGi 1301 on Scenedesmus subspicatus was caused in a high degree to the indirect effect, the light absorption in the coloured test solutions. However, at the highest test concentration a real toxic effect of the test substance on the growth of Scenedesmus subspicatus can not be excluded. Therefore, the results of this experimental part, where the algae grew in the test media with dissolved test substance as in a usual algal growth inhibition test should be taken into consideration for the determination of the toxic effect of the test substance on the growth of Scenedesmus subspicatus.

In this experimental part the test substance had a statistically significant inhibitory effect (results of a Dunnett-test, one-sided, a = 0.05) on the growth of Scenedesmus subspicatus after the exposure period of 72 hours first at the concentration of 7.9 mg test substance/l (mean measured concentration of main compound at the nominal concentration of 19.5 mg/l). Thus, this test concentration was determined as the 72 -hours LOEC (lowest concentration tested with toxic effects). The 72-hour NOEC (highest concentration tested without toxic effects after a test period of 72 hours) was determined at the concentration of 2.7 mg test substance/l (mean measured concentration of nominal 6.1 mg/l), since up to and including this test concentration the mean growth rates of the algae were statistically not significantly lower than in the control.

Applicant's summary and conclusion

Conclusions:

ErC50 (72 h) > 200 mg/l based on nominal concentration (corresponding to > 121 mg/l based on measured concentration)