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Environmental fate & pathways

Biodegradation in water: screening tests

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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

Referenceopen allclose all

Reference Type:
other: re-evaluation of "Bayer AG, 1974"
Title:
Unnamed
Year:
2010
Reference Type:
study report
Title:
Unnamed
Year:
1974
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:
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

Reference
Name:
Unnamed
Type:
Constituent
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 concentrationopen allclose all
Initial conc.:
0.3 mg/L
Based on:
test mat.
Initial conc.:
0.92 mg/L
Based on:
test mat.
Initial conc.:
3 mg/L
Based on:
test mat.
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

% Degradationopen allclose all
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
20 d
Remarks on result:
other: 0.3 mg/l
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
20 d
Remarks on result:
other: 0.92 mg/l
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
20 d
Remarks on result:
other: 3 mg/l
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).