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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:
19 Jul - 17 Aug 1994
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report Date:
1994

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
Basic Blue 123 Cl

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
sewage, predominantly domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: ARA Reinach CH, 19 July 1994
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
25 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 OECD 302B
- Test temperature: Room temperature
- pH adjusted: no
- Lighting: indirect daylight

TEST SYSTEM
- Culturing apparatus: glass vessels
- Number of culture flasks/concentration: 2
- Other: total test volume 250 mL per vessel

Measurement frequency: 1, 2, 5, 6, 7, 9, 13, 16, 19, 21, 23, 26, 27 and 28 d

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control: no, but OECD 209 run 9in parallel (3-h IC50 = 66 mg/L)
Reference substance
Reference substance:
diethylene glycol

Results and discussion

% Degradation
Key result
Parameter:
% degradation (DOC removal)
Value:
37.5
Sampling time:
28 d
Details on results:
Adsorption after 3 h: ca. 20.5%

BOD5 / COD results

Results with reference substance:
100% biodegradation after 6 d

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not inherently biodegradable
Conclusions:
The test item is not inherently biodegradable based on a biodegradation rate of 37.5% after 28 d (DOC removal).