Disodium 4-hydroxy-3-[[2-methoxy-5-methyl-4-[(4-sulphonatophenyl)azo]phenyl]azo]-7-(phenylamino)naphthalene-2-sulphonate

Toxicity to aquatic plants other than algae

Administrative data

Endpoint:

toxicity to aquatic plants other than algae

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:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 221 (Lemna sp. Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Direct Violet 9

IUPAC Name:

Direct Violet 9

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

yes

Test organisms

Test organisms (species):

Lemna minor

Details on test organisms:

Exponential growing plant monoculture of Lemna minor (Umweltbundesamt, FGIII 2.5, Überwachungsverfahren Abwasserentsorgung, Schichauweg 58, D-12307 Berlin)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

7 d

Test conditions

Test temperature:

Temperature 24 ± 2 °C

pH:

pH 6.5 at the beginning of the test; the pH value in the blank control should not increase by more than 1.5 units during the test.

Nominal and measured concentrations:

The test was performed as a limit test at 174.5 mg/l test item, corresponding to 100 mg/l A.I

Details on test conditions:

Test vessel
400 ml beakers, all-glass, with 200 ml of test medium. The beakers were covered with black paper up until the 200 ml mark to ensure that illumination comes only from above and not from the sides.

Test medium
Swedish standard-Medium (SIS Medium; Table 2), prepared with ultra-pure water

Pre-culture
Exponentially growing plant monoculture of Lemna minor (the culture was visibly free from contamination by other organisms such as algae and protozoa).

Illumination Intensity:
continuous (6500–10000 lux) from Osram Fluora L18W77 (Osram AG, Winterthur, Switzerland) and CH Lighting F18T8/6500K EUP (CH Lighting CO., Ltd., China)

Incubation Beakers were incubated on a black non-reflecting surface.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

The test concentrations of Direct Violet 9 during the 7 day test period were determined by photometry at the beginning of the test, as well as after 3, 5 and 7 days of exposure. These analyses confirmed the right dosage of the test item, but showed that the concentrations of the test item decreased over the whole 7 day test period. The measured concentrations of the active ingredient were 93.2, 78.8, 73.1 and 81.5 mg/l after 0, 3, 5 and 7 days, respectively. As they did not remain in the 80-120% range of the nominal concentration, the effective concentrations (ErC50 and EyC50) were assessed based on the geometric mean (GM) of the measured concentrations of the active ingredient, i.e. 81.3 mg/l.
With respect to growth rate inhibition, no significant effects as compared to the untreated controls were observed at the tested concentration.
With respect to yield inhibition, no significant effects as compared to the untreated controls were observed at the tested concentration.
Based on the above considetations, the tested substance should be considered as not toxic for aquatic plants and the EC50 growth rate/frond numbers is set at > 100 mg/l.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The results show that the tested item is not toxic to Lemna minor with EC50 > 100 mg/L.

Executive summary:

No significant effects as compared to the untreated controls were observed at the tested concentration with respect to growth rate inhibition, and to yield inhibition.