[1,1'-Biphenyl]-2-carbonitrile, 4'-[(1,4'-dimethyl-2'-propyl[2,6'-bi-1H-benzimidazol]-1'-yl)methyl]-

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2 August- 3 August 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted in GLP compliance and in accordance with several internationally established guidelines (OECD, EEC, EPA guidelines, see below).

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

not specified

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Deviations:

not specified

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

480-420-2

EC Name:

-

Cas Number:

144702-27-2

Molecular formula:

C33 H29 N5

IUPAC Name:

4'-{[4-methyl-6-(1-methyl-1H-1,3-benzodiazol-2-yl)-2-propyl-1H-1,3-benzodiazol-1-yl]methyl}-[1,1'-biphenyl]-2-carbonitrile

Test material form:

other: solid

Details on test material:

- Name of test material (as cited in study report): BIBR 277 Nitril
- Physical state: Solid
- Analytical purity: 99.7%
- Lot/batch No.: T02/03
- Expiration date of the lot/batch: April 2006
- Storage condition of test material: At room temperature, dark and dry.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): STP for domestic sewage in Veszprem, Hungary

The activated sludge was washed by centrifugation, supernatant liquid was decanted. The solid material was re-suspended in an isotonic saline solution and centrifuged again (procedure was repeated twice). An aliquot of the final sludge suspension was weighed, dried and the ratio of wet/dry weight was determined.
based on this ratio, calculated aliquots of washed sludge suspension containing 4g dry material/L were mixed with test water and aerated until use. Before use, sludge was filtered with cotton wool.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

2 mg/L

Based on:

ThOD/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: grade salts were added to deionised water to give stock solutions. Stock solutions were diluted in deionised water, aerated for 20 minutes and allowed to stand for 20 hrs at the test temperature. Dissolved oxygen concentration was about 9.0 mg/L prior to starting the test.
- Test temperature: 20°C
- pH: 7.2 (at the start of the test)
- pH adjusted: no
- Aeration of dilution water: yes (see above)


TEST SYSTEM
- Culturing apparatus: BOD 300 mL bottles
- Number of culture flasks/concentration: Each 16 (+2 reserve) bottles containing: a) the test item and inoculum, b) the reference item and inoculum (positive control), c) only inoculum (inoculum control) and d) test item, reference item and inoculum (toxicity control).
- Method used to create aerobic conditions: inoculum and medium solutions were sufficiently aerated prior to the start of the test.
- Measuring equipment: self-stirring O2 electrode
- Test performed in closed vessels: yes
- Details of trap for CO2 and volatile organics if used: not used


SAMPLING
- Sampling frequency: oxygen was measured at days 0, 2, 5, 7, 12, 14, 21 and 28 after the start of the test.
- Sampling method: no sampling was performed for oxygen analysis, the oxygen concentrations were measured with an oxygen meter with a stirring O2 electrode.
- Sterility check if applicable: no
- Sample storage before analysis: no
- Other: Nitrite and nitrate concentrations were measured (representing oxidized nitrogen within the test solutions) via HPLC-UV analysis. Samples were directly injected.

CONTROL AND BLANK SYST EM
- Inoculum blank: yes
- Abiotic sterile control: no
- Toxicity control: yes
- Other: see above for details

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

% Degradation

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

Details on results:

The residual oxygen concentration did not drop below 0.5 mg O2/L at any time. The difference in duplicate samples was less than 20%.

BOD5 / COD results

BOD5 / COD

Parameter:

BOD5

Value:

mg O2/g test mat.

Results with reference substance:

The percentage of degradation of the reference substance item reached the passt level for ready biodegradability (> 60%) within 14 days.
The oxygen consumption in the inoculum control did not exceed 1.5 mg/L after 28 days.

Any other information on results incl. tables

The BOD valued were not corrected for nitrification, because the quantity of total oxidised nitrogen (nitrite and nitrate) were below the LOQ of HPLC-UV analysis or was about 0 after the correction with control values.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable

Conclusions:

Under the test conditions the percentage biodegradation of BIBR 277 Nitril reached a mean of -1% after 28 days of incubation, based on ThOD (No3).The test item is regarded to be not readily biodegradable.