1H-Benz[e]indolium, 2-[2-[2-chloro-3-[2-[1,3-dihydro-1,1-dimethyl-3-(4-sulfobutyl)-2H-benz[e]indol-2-ylidene]ethylidene]-1-cyclohexen-1-yl]ethenyl]-1,1-dimethyl-3-(4-sulfobutyl)-, inner salt, ammonium salt (1:1)

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)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Test guideline 3

Qualifier:

according to guideline

Guideline:

ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum)

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23, December 14,2000.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-[(1E)-2-[(3Z)-2-chloro-3-{2-[(2E)-1,1-dimethyl-3-(4-sulfobutyl)-1H,2H,3H-benzo[e]indol-2-ylidene]ethylidene}cyclohex-1-en-1-yl]ethenyl]-1,1-dimethyl-3-(4-sulfonatobutyl)-1H-benzo[e]indol-3-ium amine

EC Number:

700-626-0

Cas Number:

1073607-50-7

Molecular formula:

C46 H50 Cl N2 O6 S2 . H4 N

IUPAC Name:

2-[(1E)-2-[(3Z)-2-chloro-3-{2-[(2E)-1,1-dimethyl-3-(4-sulfobutyl)-1H,2H,3H-benzo[e]indol-2-ylidene]ethylidene}cyclohex-1-en-1-yl]ethenyl]-1,1-dimethyl-3-(4-sulfonatobutyl)-1H-benzo[e]indol-3-ium amine

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Analysis performed on samples at the start, at 24h and at 74h of exposure.

Test solutions

Vehicle:

no

Details on test solutions:

Preparation of test solutions started with a loading rate of 100mg/l applying a 16-minute period of ultrasonic treatment in combination with stirring. Thereafter, the aqueous dispersion was magnetically stirred for three days to ensure reaching maximum dissolution in test medium. The resulting green dispersion contained precipitate and floating small particles at the surface and through the dispersion. The dispersion was consequently filtered througha 0.45µm membrane filter to remove the undissolved material. This resulted in a very slightly green filtrate that was used as highest test concentration. The lower test concentrations were prepared by subsequent dilutions of the filtrat in test medium. The dilutions were all clear and colourless.

Test organisms

Test organisms (species):

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

Details on test organisms:

strain: NIVA CHL 1

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Test conditions

Hardness:

24mg/l expressed as CaCO3

Test temperature:

at the start: 21.8°C
during the exposure period: 22.4-22.8°C

pH:

7.6-8.1

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 1.4 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: both for growth rate and yield inhibition

Remarks on result:

other: The initial measured exposure concentration corresponds to a loading concentration of >100mg/l.

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.4 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: both for growth rate and yield inhibition

Remarks on result:

other: The initial measured exposure concentration corresponds to a loading concentration of 100mg/l.

Any other information on results incl. tables

Acceptability of the test:

1. In the controls, cell density increased by an average factor of >16 within two days.

2. The mean coefficient of variation for section-by-section specific growth rates in the control cultures did not exceed 35%.

3. The coefficient of variation of average specific growth rates during the whole test period in replicate control cultures did not exceed 7%.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Both the EC50 for growth rate reduction and the EC50 for yield inhibition exceeded the initial measured concentration of 1.4mg/l, being the maximum soluble concentration of test substance in test medium.
Due to the very low solubility of test substance in test medium, concentration levels that might be toxic for algae could not be reached.