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Environmental fate & pathways

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:
04.05.11 to 08.06.11
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Report on substance meets the criteria for classification as reliable without restriction according to Klimisch et al (1997)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011
Report date:
2011

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
no
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Tetrapotassium 5,5'-{ethane-1,2-diylbis[thio-1,3,4-thiadiazole-5,2-diyldiazene-2,1-diyl(5-amino-3-tert-butyl-1H-pyrazole-4,1-diyl)]}diisophthalate
EC Number:
700-616-6
Cas Number:
849608-59-9
Molecular formula:
C36H32K4N14O8S4
IUPAC Name:
Tetrapotassium 5,5'-{ethane-1,2-diylbis[thio-1,3,4-thiadiazole-5,2-diyldiazene-2,1-diyl(5-amino-3-tert-butyl-1H-pyrazole-4,1-diyl)]}diisophthalate

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, adapted
Details on inoculum:
- Source of inoculum/activated sludge: Totnes Sewage Treatment Works, Totnes, Devon, UK
- Storage conditions: Room temperature, aerated, maintained at pH 7.0 +/- 1 degree centigrade.
- Preparation of inoculum for exposure: Centrifuged, washed and resuspended in mineral medium
- Concentration of sludge: 30 mg/L
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Test temperature: 22 degrees centigrade +/- one degree
- pH: 6.7-7.5
- Continuous darkness: yes

TEST SYSTEM
- Measuring equipment: Oxitop respirometer
- Test performed in open system: no
- Details of trap for CO2 and volatile organics if used:CO2 absorbed by KOH solution in a seal cup in neck of bottle

SAMPLING
- Sample storage before analysis: ambient temperature
Reference substance
Reference substance:
benzoic acid, sodium salt
Remarks:
100 mg/L

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (O2 consumption)
Value:
< 5
Sampling time:
5 d
Parameter:
% degradation (O2 consumption)
Value:
< 5
Sampling time:
10 d
Parameter:
% degradation (O2 consumption)
Value:
< 5
Sampling time:
15 d
Parameter:
% degradation (O2 consumption)
Value:
< 5
Sampling time:
20 d
Parameter:
% degradation (O2 consumption)
Value:
< 5
Sampling time:
28 d

BOD5 / COD results

Results with reference substance:
Sodium benzoate attained a maximum mean level of biodegradation (based on BOD:ThOD ratio) of 67%. >60% degradation was acheived in the 10 day window.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
It is concluded that in this study the test substance failed to meet the criteria for ready biodegradability.