Reaction mass of 5,5'-[vinylenebis[(3-sulpho-p-phenylene)azo]]bis[3-methylsalicylic] acid, potassium salt, compound with 2,2',2''-nitrilotriethanol and potassium 5-amino-3-{[4-(2-{4-[(7-amino-1-hydroxy-3-sulfo-2-naphthyl)diazenyl]-2-sulfophenyl}vinyl)-3-sulfophenyl]diazenyl}-4-hydroxy-7-sulfonaphthalene-2-sulfonate - 2,2',2''-nitrilotriethanol (1:1) and 3,3'-[vinylenebis[(3-sulpho-p-phenylene)azo]]bis[5-amino-4-hydroxynaphthalene-2,7-disulphonic] acid, potassium salt, compound with 2,2',2''-nitrilotriethanol and 3,3'-[vinylenebis[(3-sulpho-p-phenylene)azo]]bis[6-amino-4-hydroxynaphthalene-2-sulphonic] acid, potassium salt, compound with 2,2',2''-nitrilotriethanol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2016-11-08 to 206-12-21

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Municipal waste water treatment plant Mannheim, Germany
- Preparation of inoculum for exposure: Inoculum was pre-aerated two days before the start of the test.
- Initial cell/biomass concentration: 30 mg/L dry substance

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

TOC

Initial conc.:

52 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Test temperature: 22 ± 2 °C

TEST SYSTEM
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: pre-aeration for two days before test start
- Measuring equipment: carbon dioxide trap
- Test performed in open system: no

SAMPLING
- Sampling frequency: every other day

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Other: Inhibition control

Reference substance:

aniline

Remarks:

20 mg/L TOC

Preliminary study:

The total Organic Carbon was determined to be 381 mg/g.

Key result

Parameter:

% degradation (CO2 evolution)

Value:

> 30 - < 40

Sampling time:

28 d

Details on results:

The test substance was biodegraded by 30-40 % over 28 days. The test substance is determined to be not readily but inherently biodegradable according to the OECD criteria. The required pass level for ready biodegradability within a ten days window was not reached.

Results with reference substance:

The degree of biodegradation of the reference substance was determined to be 66 % CO2/ThCO2 after 14 days.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Description of key information

The ready biodegradability of the test substance was investigated in a study (BASF SE, 2017) according to the OECD guideline 301 B (1992). The test substance was biodegraded by 30 - 40 % over 28 days. The test substance is determined to be not readily but inherently biodegradable according to the OECD criteria.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The ready biodegradability of the test substance was investigated in a study (BASF SE, 2017) according to the OECD 301 B (1992) under GLP conditions. The biodegradation of the test substance was followed by exposing it over 28 days in the activated sludge from a municipal sewage plant (Municipal waste water treatment plant Mannheim, Germany). The inoculum was collected from the aeration tank of the plant. A suitable aliquot of the activated sludge suspension was sieved by a finely woven mesh with a mesh size about 1 mm. At the day of exposure the suspension was washed one time with drinking water. After settling, the supernatant was discarded and the remaining sludge suspension was filled up with drinking water and the concentration of the sludge was adjusted to 6.0 g/L dry weight. Aliquots of 7.5 mL were added to the test vessels to obtain an activated sludge concentration of 30 mg/L dry weight. To reduce the content of inorganic carbon in the blank controls the activated sludge was aerated with carbon dioxide free air for about 48 hours at 22 ± 2 °C. The incubation bottles were stirred on magnetic stirrers; the aeration was performed with carbon dioxide free air at a flow of approximately 800 mL per hour. The TIC- and DOC-analyses were performed as repeat determination. The bottles were connected to two serial scrubbing bottles (total volume 250 mL) filled with 100 mL 0.05 mol sodium hydroxide solution for the adsorption of carbon dioxide from biodegradation processes. Usually twice a week the Total Inorganic Carbon (TIC) values of the adsorption solutions of the first trap were determined and used for the calculation of the produced carbon dioxide. After each sampling the second trap was moved forward and the new trap with fresh sodium hydroxide solution was placed into the second position. Each trap was analyzed separately. The TIC-value of the freshly prepared sodium hydroxide solution was determined and considered by the calculation of biogenic produced carbon dioxide amount. The initial concentration of the test substance was ca. 52.5 mg/L (corresponding to 20 mg/L TOC). As a reference compound (aniline) was tested simultaneously under the same conditions. In the toxicity control no inhibitory effect on the microorganisms was observed. In the procedure controls, the reference compound aniline was biodegraded by 66 % after 14 days of exposure.  The required pass level for ready biodegradability within a ten days window was not reached. At the end of the test, after 28 days the test substance was biodegraded by 30 - 40 %. The test substance is determined to be not readily but inherently biodegradable according to the OECD criteria. The validity criteria were met.