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)

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

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 301 B (Ready Biodegradability: CO2 Evolution Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Test guideline 3

Qualifier:

according to guideline

Guideline:

ISO DIS 9439 (Ultimate Aerobic Biodegradability - Method by Analysis of Released Carbon Dioxide)

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: ISO Standard 10634 "Water Quality - Guidance for the preparation and treatment of poorly water-soluble organic compounds for the subsequent evaluation of their biodegradability in an aqueous medium" (1995)

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

Details on test material:

Since the test substance was not sufficiently soluble to allow preparation of an aqueous solution at a concentration of 1 g/l, weighed amounts were added to the 2-litres test bottles containing medium with microbial organisms and mineral components. To this end, 20 ml of Milli-RO water was added to each weighing bottle containing the test substance. After vigorous mixing (vortex) the resulting suspension was added quantitatively to the test medium. The test solutions were continuously stirred during the test, to ensure optimal contact between the test substance and the test organisms.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

The freshly obtained sludge was kept under continuous aeration until further treatment. The concentration of suspended solids was 3.4g/l in the concentrated sludge (information obtained from the municipal sewage treatment plan). Before use, the sludge was allowed to settle (32 minutes) and the supernatant liquid was used as inoculum at the amount of 10ml/l of mineral medium.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

18.5 mg/L

Based on:

other: corresponding to 12mg TOC/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

The study consisted of six bottles:
- 2 inoculum blanks (no test substance)
- 2 test bottles (test substance)
- 1 positive control (sodium acetate)
- 1 toxicity control (test substance + sodium acetate)

Reference substance

Reference substance:

acetic acid, sodium salt

Remarks:

positive control and part of toxicity control

Results and discussion

Test performance:

1. temperature: The temperature recorded in a vessel with water in the same room varied between 21.9 and 22.9°C.
2. pH:
inoculum blanks: 7.5 (start) 7.6 (day 28)
positive control: 7.5 (start) 7.8 (day 28)
toxicity control: 7.5 (start) 7.8 (day 28)
test substance: 7.5 (start) 7.6 (day 28)

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

>= 18 - <= 19

St. dev.:

1

Remarks on result:

other: Biodegradation was determined on day 2, 5, 7, 9, 14, 19, 23, 27 and 29.

Details on results:

In the toxicity control, the test substance was found not to inhibit microbial activity (more than 25% biodegradation occurred withiin 14 days)..

Any other information on results incl. tables

Acceptability of the test:

1. The positive control substance was biodegraded by at least 60% (76%) within 14 days.

2. The difference of duplicate values for %-degradation of the test substance was always less than 20.

3. The total CO2 release in the blank at the end of the test did not exceed 40 mg/l (52.5 mg CO2 per 2 litres of medium, corresponding to 26.3 mg CO2/l).

4. The Inorganic Carbon content (IC) of the test substance (suspension) in the mineral medium at the beginning of the test was less than 5% of the Total Carbon content (TC). Since the test medium was prepared in tap-water purified by reverse osmosis (Milli-RO water (Millipore Corp., Bedford, Mass., USA, carbon levels < 500 ppb)), IC was less than 5% of TC (mainly coming from

the test substance, 12 mg TOC/l).

Since all criteria for acceptability of the test were met, this study was considered to be valid.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other:

Conclusions:

Not readily biodegradable