1-chloro-2-nitrobenzene

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:

1974

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions.

Data source

Reference

Reference 1

Reference Type:

other: re-evaluation of "Bayer AG, 1974"

Title:

Unnamed

Year:

2010

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1974

Reference 3

Reference Type:

secondary source

Title:

1-Chloro-2-nitrobenzene CAS: 88-73-3, SIDS Initial Assessment Report

Author:

OECD

Year:

2001

Bibliographic source:

UNEP publications

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

: 1) use of adapted activated sludge 2) test duration 20 d instead of 28 d

Principles of method if other than guideline:

Test was performed before actual guideline was established.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

1-chloro-2-nitrobenzene

EC Number:

201-854-9

EC Name:

1-chloro-2-nitrobenzene

Cas Number:

88-73-3

Molecular formula:

C6H4ClNO2

IUPAC Name:

1-chloro-2-nitrobenzene

Details on test material:

- Name of test material (as cited in study report): o-Nitrochlorobenzene
- Analytical purity: no data

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial, adapted

Details on inoculum:

- Source of inoculum/activated sludge: laboratory scale sewage treatment unit
- Pretreatment: adaptation
- Concentration of sludge: 1 mL/L
- Initial cell/biomass concentration: 10E3 to 10E6 bacteria per litre (low bacteria density)

Duration of test (contact time):

20 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

0.3 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

0.92 mg/L

Based on:

test mat.

Initial test substance concentration 3

Initial conc.:

3 mg/L

Based on:

test mat.

Initial test substance concentration 4

Initial conc.:

9.2 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

(expressed as BOD)

Details on study design:

TEST CONDITIONS
- Additional substrate: no
- Test temperature: 20 ± 1 °C
- pH: 6.1
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: completely filled closed bottles
- Number of culture flasks/concentration: no data


SAMPLING
- Sampling frequency: 5d, 10d, 20d


CONTROL AND BLANK SYSTEM
- Inoculum blank: yes


STATISTICAL METHODS: no data

Reference substance

Reference substance:

other: phenol

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

20 d

Remarks on result:

other: 0.3 mg/l

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

20 d

Remarks on result:

other: 0.92 mg/l

% Degradation 3

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

20 d

Remarks on result:

other: 3 mg/l

% Degradation 4

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

20 d

Remarks on result:

other: 9.2 mg/l

Details on results:

Chloride negative

Applicant's summary and conclusion

Interpretation of results:

under test conditions no biodegradation observed

Executive summary:

In 1974 Bayer AG assessed the biodegradability of o-Nitrochlorobenzene in a study similar to the later published OECD TG 301 D (Closed Bottle Test). In deviation to the guideline adapted activated sludge was used as inoculum. Taking into account the high toxicity of o-Nitrochlorobenzene on microorganisms low test substance concentrations of 0.3, 0.92, 3 and 9.2 mg/l were tested. After a 20 day exposure period even with adapted inoculum 0 % degradation was determined based on oxygen consumption (BOD), thus o-Nitrochlorobenzene is considered not to be readily biodegradable (re-evaluation of Bayer AG, 1974).

Examination of the degradation pathway of chloronitrobenzenes, showed these substances only to be biodegraded by isolated bacteria and adapted mixed sludge as long as the chloronitrobenzenes are not the only sole source for carbon and nitrogen (OECD SIDS, 2001; Kuhlmann, 1999).