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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: inherent biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
16 Jan - 13 Feb 1995
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995
Report Date:
1995

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)
Version / remarks:
08/1989
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Details on test material:
Basic Red 14 H2PO4

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
Inoculum I (Wupperverband): small wastewater treatment plant with domestic sewage
Inoculum II (KA Odenthal): large wwtp with domestic sewage
Inoculum III (GKW Bürrig): predominantly industrial sewage

Day of collection: 16 Jan 1994
Pretreatment: washed twice, separation via centrifugation
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
TEST CONDITIONS
- Composition of medium: mineral medium according to guideline
- Test temperature: 20-25°C

SAMPLING
- Sampling frequency: 0h, 3h, 7d, 14d, 21d, 28d

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Key result
Parameter:
% degradation (DOC removal)
Remarks:
mean of three tests
Value:
7
St. dev.:
0.47
Sampling time:
28 d
Details on results:
Inoculum I: 7% after 28 d
Inoculum II: 7% after 28 d
Inoculum III: 6% after 28 d
All values corrected with blind value

BOD5 / COD results

Results with reference substance:
100% after 14 d

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not inherently biodegradable
Conclusions:
The inherent biodegradability of the test item was determined in three inocula of different wastewater treatment plants. Based on the DOC removal after 28 d, the mean biodegradation rate was calculated at 7%. The substance is therefore not considered inherently biodegradable in the OECD 302B test.