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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: inherent biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1993
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
None
Qualifier:
according to
Guideline:
OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)
Deviations:
no
Principles of method if other than guideline:
Guideline followed
GLP compliance:
yes (incl. certificate)
Specific details on test material used for the study:
None
Oxygen conditions:
aerobic
Inoculum or test system:
sewage, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Sludge of a biological sewage treatment plant (ARA-Therwil) collected on 22.06.93
Duration of test (contact time):
28 d
Initial conc.:
150 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
Experimental conditions:
Water/Nutrient: according to the specification of the EEC L133 (pp. 99-105) Volume 31 resp. OECD Method 302B.
Temperature: 22.0 ± 3°C (room temperature)
Test duration: 28 days
Lighting: indirect daylight
Estimation Technique: TOC/DOC Analyzer/ SHIMADZU TOC-500
Reference substance:
diethylene glycol
Preliminary study:
None
Test performance:
None
Key result
Parameter:
% degradation (DOC removal)
Value:
4
Sampling time:
28 d
Details on results:
Test substance:
The bioelimination of FAT - 92'348/A measured as DOC after 28 days corrected by the blank control is: 4.0 % (average of 2 tests running in parallel)
Adsorption after 3 hours: 3.6 %

Reference substance:
The bioelimination, corrected by the blank control and measured as DOC (mg/l) is: 98.7 % 16th day
Results with reference substance:
The bioelimination, corrected by the blank control and measured as DOC (mg/l) was: 98.7 % on 16th day.

None

Validity criteria fulfilled:
yes
Interpretation of results:
not inherently biodegradable
Conclusions:
The bioelimination of the test substance FAT - 92348/A after 28 days was: 4.0 %.
Executive summary:

The inherent biodegradability of FAT - 92348/A was determined in a 28 days Zahn-Wellens Test according to the OECD Guideline for Testing of Chemicals, No. 302B, Paris 1981 and the EEC-Directive, L133 (pp. 99-105) Volume 31, May 88, in accordance with GLP.

The test substance was tested in concentration of 150 mg/l DOC. The reference substance diethylene glycol was also tested in a concentration of 150 mg/l DOC.

The bioelimination of the test substance FAT - 92'348/A after 28 days was: 4.0 %, while the bioelimination of the reference substance after 16 days was: 98.7 %.

Description of key information

FAT 92348/A is neither readily nor inherently biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

In the key study, the inherent biodegradability of FAT - 92348/A was determined in a 28-day Zahn-Wellens - Test according to the OECD Guideline for Testing of Chemicals, No. 302B, Paris 1981 and the EEC-Directive, L133 (pp. 99-105) Volume 31, May 88, in accordance with GLP. The test substance was tested in concentration of 150 mg/l DOC. The reference substance Diethylenglycol was also tested in a concentration of 150 mg/l DOC. Based on the findings of the study, the bioelimination of the test substance FAT 92348/A after 28 days was estimated to be 4.0 %, while the bioelimination of the reference substance after 16 days was 98.7 %.

In two separately conducted studies in 1993, the Biological Oxygen Demand (BOD5) of FAT - 92348/A over a duration of 5 days was estimated to be 8 mg 02/g, while the COD of determined to be 855 mg O2/g. Hence, the BOD5/COD ratio was calculated to be 8/855 = 0.009, which indicates substance to be not rapidly biodegradable.

For FAT 40065/A (1974), BOD5 was found to be 56 mg/g O2 and COD was found to be 817 mg/g O2. Correspondingly the BOD5/COD quotient is calculated to 0.069 at pH= 4.8. The substance is considered to be not rapidly biodegradable.

Hence all the available data point to the substance being neither readily nor inherently biodegradable.