Pentyl 2-cyano-(3-(6-methoxybenzothiazol-2-ylimino)-2,3-dihydro-1H-isoindol-1-ylidene)acetate

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 Oct. 26, 2000 to Nov. 27, 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Secondary effluent of a domestic sewage treatment plant (KIäranlage Odenthal)
- Preparation of inoculum for exposure: Separation of coarse particles by filtration
- Pretreatment: Aeration of mineral medium plus inoculum (filtrate) for 6 d
- Concentration of effluent in reaction mixture: 5 mL/L

Duration of test (contact time):

28 d

Initial conc.:

3.7 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral medium

TEST SYSTEM
- Culturing apparatus: Bottles
- Number of culture flasks/concentration: 10 bottles
- Test performed in closed vessels due to significant volatility of test substance: Yes
- Test performed in open system: No

SAMPLING
- Sampling frequency: 7, 14, 21 and 28 d
- Sampling method: Degradation is followed by analysis of dissolved oxygen over a 28 d period. The amount of oxygen taken up by the microbial population during biodegradation of the test substance, corrected for uptake by the blank inoculum run in parallel, is expressed as a percentage of ThOD or COD.

CONTROL AND BLANK SYSTEM
- Inoculum blank: A measured volume of mineral medium containing only inoculum
- Procedure control: The reference chemical sodium benzoate is tested by setting up 2 flasks in parallel to the normal tests runs
- Toxicity control: containing test substance, reference substance and inoculum

Reference substance:

benzoic acid, sodium salt

Remarks:

2.9 mg/L

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

14 d

Details on results:

Theoretical oxygen demand: 1899 mg O2/g

Results with reference substance:

The reference substance showed 78 % degradation after 14 and 28 d.
Theoretical oxygen demand: 1665 mg O2/g

Toxicity control: Showed 32 % of degradation after 14 and 28 d.

The used concentrations of the test substance did not show toxic effects to bacteria.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Under the test conditions, the test substance is not readily biodegradable.

Executive summary:

A study was performed to assess the ready biodegradability of test substance according to EU Method C.4-E. and OECD Guideline 301 D in compliance with GLP.

The test substance in a mineral medium was inoculated with secondary effluent and incubated for 28 d under aerobic conditions in completely full, closed bottles. During this period the biodegradation is followed by analysis of dissolved oxygen. The amount of oxygen taken up by the test chemical, corrected for uptake by the blank inoculum run in parallel, is expressed as a percentage of theoretical oxygen demand (ThOD) or chemical oxygen demand (COD).

The test substance showed 0 % degradation after 7, 14, 21, 28 d. Therefore, the test substance is classified as not readily biodegradable. The reference substance showed 78 % degradation after 14 d.

Under the test conditions, the test substance is classified as not readily biodegradable.

Description of key information

The test substance is not readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

A study was performed to assess the ready biodegradability of test substance according to EU Method C.4-E. and OECD Guideline 301 D.

The test substance in a mineral medium was inoculated with secondary effluent and incubated for 28 d under aerobic conditions in completely full, closed bottles. During this period the biodegradation is followed by analysis of dissolved oxygen. The amount of oxygen taken up by the test chemical, corrected for uptake by the blank inoculum run in parallel, is expressed as a percentage of theoretical oxygen demand (ThOD) or chemical oxygen demand (COD).

The test substance showed 0 % degradation after 7, 14, 21, 28 d. Therefore, the test substance is classified as not readily biodegradable. The reference substance showed 78 % degradation after 14 d. The test substance is classified as not readily biodegradable (Dr. Muller, 2000).