hexasodium 5,5'-{[2,7-disulfonato-9-(2-sulfonatophenyl)-9H-xanthene-9-ylium-3,6-diyl]bis(azanediyl)bis[(2,4,6-trimethyl-3,1-phenylene)aminosulfonyl]}diisophthalate

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:

Experimental start date 29 January 2018. Experimental completion date 17 May 2018.

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

hexasodium 5,5'-{[2,7-disulfonato-9-(2-sulfonatophenyl)-9H-xanthene-9-ylium-3,6-diyl]bis(azanediyl)bis[(2,4,6-trimethyl-3,1-phenylene)aminosulfonyl]}diisophthalate

EC Number:

854-560-3

Cas Number:

1891094-25-9

Molecular formula:

C53H38N4Na6O22S5

IUPAC Name:

hexasodium 5,5'-{[2,7-disulfonato-9-(2-sulfonatophenyl)-9H-xanthene-9-ylium-3,6-diyl]bis(azanediyl)bis[(2,4,6-trimethyl-3,1-phenylene)aminosulfonyl]}diisophthalate

Test material form:

solid: particulate/powder

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Details on test solutions:

A nominal amount of test item (62.5 mg) was dissolved in culture medium and the volume adjusted to 500 mL to give a 100 mg ai/L stock solution from which a series of dilutions was made to give further stock solutions of 33.3, 11.1, 3.7 and 1.2 mg ai/L. An aliquot (250 mL) of each of the stock solutions was separately inoculated with algal suspension (1.2 mL) to give the required test concentrations of 1.2, 3.7, 11.1, 33.3 and 100 mg ai/L.
The stock solutions and each of the prepared concentrations were inverted several times to ensure adequate mixing and homogeneity.

Test organisms

Test organisms (species):

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

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

Temperature was maintained at 24 ±1 ºC throughout the test.

pH:

The pH value of the control cultures was observed to increase from pH 7.5 at 0 hours to pH 8.5 at 72 hours. The pH deviation in the control cultures was less than 1.5 pH units after 72 hours and therefore was within the limits given in the Test Guidelines.

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

ca. 33.3 other: mg ai/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 11.1 other: mg ai/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Details on results:

Analysis of the test preparations at 0 and 72 hours showed measured test concentrations to be near nominal with the exception of the 1.2 mg ai/L test preparations where measured concentrations of 131% and 127% of nominal were obtained at 0 and 72 hours respectively. Analysis of the duplicate 0-Hour preparation gave a measured concentration of 173% of nominal. Such high and variable values were considered to be due to an artefact of the analytical method. As the test concentration of 1.2 mg ai/L fell below both the ECx and NOEC values it was considered appropriate to calculate the results based on nominal test concentrations only.

Any other information on results incl. tables

Inhibition of growth rate

ErC10 (0 to 72 hour) : 79 mg ai/L

ErC20 (0 to 72 hour) : >100 mg ai/L

ErC50 (0 to 72 hour) : >100 mg ai/L

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The effect of the test item on the growth of Pseudokirchneriella subcapitata has been investigated over a 72-Hour period and gave the following results:
Response Variable
Growth rate -EC10 (mg ai/L) was 79
Growth rate EC20 (mg ai/L) >100
Growth rate EC50 (mg ai/L) >100
Growth RateNo Observed Effect Concentration (NOEC) (mg ai/L) measured at 11.1
Growth RateLowest Observed Effect Concentration (LOEC) (mg ai/L)measured at 33.3

Executive summary:

Introduction

The study was performed to assess the effect of the test item on the growth of the green alga Pseudokirchneriella subcapitata. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (2006) No 201, "Freshwater Alga and Cyanobacteria, Growth Inhibition Test" referenced as Method C.3 of Commission Regulation (EC) No 761/2009.