Benzonitrile

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:

1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Guideline study (OECD 301 E) with acceptable restrictions which do not impair the overall conclusion from the data; buffer used has a higher capacity than that described in OECD Guideline, incubation at 20+/-2°C instead of 22+/-2°C, no information about light conditions; information on purity of test substance is missing,but as ths substance is readily biodegradable potential impurities don't have a negative influence on the test result.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

Deviations:

yes

Remarks:

incubation at 20+/-2°C instead of 22+/-2°C, no information about light conditions

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Duration of test (contact time):

28 d

Initial conc.:

12.2 mg/L

Based on:

test mat.

Initial conc.:

24.3 mg/L

Based on:

test mat.

Parameter:

% degradation (DOC removal)

Value:

0

Sampling time:

0 d

Remarks on result:

other: 12.2 mg/l BN added

Parameter:

% degradation (DOC removal)

Value:

100

Sampling time:

14 d

Remarks on result:

other: 12.2 mg/l BN added

Key result

Parameter:

% degradation (DOC removal)

Value:

100

Sampling time:

28 d

Remarks on result:

other: 12.2 mg/l BN added

Parameter:

% degradation (DOC removal)

Value:

0

Sampling time:

0 d

Remarks on result:

other: 24.3 mg/l BN added

Key result

Parameter:

% degradation (DOC removal)

Value:

100

Sampling time:

14 d

Remarks on result:

other: 24.3 mg/l BN added

Details on results:

The results show a complete degradation of sodium acetate within one week as expected of an inoculum with sufficient activity. This degradation of sodium acetate was not influenced by the presence of benzonitrile in the medium.
A complete degradation of benzonitrile took place within 7 days.
12.2 mg/l BN added 24.3 mg/l BN added
Days mg DOC/l % mg DOC/l %
0 6 0 12 0
7 0 100 1 92
14 0 100 0 100
28 1 83 1 92

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Benzonitrile is regarded as readily biodegradable.

Executive summary:

The biodegradability of the product Benzonitrile was determined by the method laid down in the OECD Guideline 301E; 'Ready Biodegaradbility: Modified OECD Screening Test'.

Benzonitrile was tested in two concentrations: 12 mg/L and 24 mg/L. A control test with sodium acetate showed that the activity of the inoculum was sufficient, and that there was no inhibition of the inoculum activity by Benzonitrile.

Significant biodegradability was found in the test bottles with Benzonitrile; this substance is regarded as readily biodegradable.

Description of key information

Benzonitriles is regarded as readily biodegradable. 

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

The biodegradability of the product Benzonitrile was determined by the method laid down in the OECD Guideline 301E; 'Ready Biodegaradbility: Modified OECD Screening Test'.

Benzonitrile was tested at two concentrations: 12 mg/L and 24 mg/L. A control test with sodium acetate showed that the activity of the inoculum was sufficient, and that there was no inhibition of the inoculum activity by Benzonitrile.

Significant biodegradability was found in the test bottles with Benzonitrile; this substance is regarded as readily biodegradable.