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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
October 2001 till January 2002
Reliability:
1 (reliable without restriction)
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Version / remarks:
, 1992
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
,signed 1999-05-25
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of activated sludge: Neustadt, (ESN), Im Altenschemel, NW-Lachen-Speyerdorf, Germany
- Charge: 18102001
- Preparation of inoculum for exposure: The activated sludge was washed 3 x with drinking water, filtered, washed again and resuspended in medium and ventilated for 12 h.
- Concentration of sludge: the dry residue was 4840 mg solid / L.
Duration of test (contact time):
29 d
Initial conc.:
20 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
Stock solution (a)-(d) were prepared as described in OECD 301 (1992)
- Composition of medium: 30 mL (a), 3 mL (b), 3 mL (c), 3 mL (d) filled with aqua demin. ad up to 1000 mL
- Test temperature: 20 +-2°C
- pH adjusted: no
- Aeration of dilution water: yes
- Suspended solids concentration: 25.8 mg/L
- Continuous darkness: without direct lighting

TEST SYSTEM
- Culturing apparatus:
- Number of culture flasks/concentration: double determination
Determination of TC and IC

SAMPLING
- Sampling frequency: 1, 3, 6, 8, 10, 13, 16, 20, 24, 28 , 29

CONTROL AND BLANK SYSTEM
- Reference substance: Aniline
- Inoculum blank: 2x
- Abiotic sterile control: 1x (HgCl2 - 1.5 g)
- Toxicity control: 1x (Testsubstance and Aniline)
Reference substance:
aniline
Key result
Parameter:
% degradation (CO2 evolution)
Value:
88
Sampling time:
28 d
Details on results:
The IC value of the reference item measured at day 24 is considered as an outlier (based on dilution)
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The test item is readily biodegradable since a 88% degradation was observed after 28 days (10-day window passed). A toxicity control was performed.

Description of key information

readily biodegradable (88 % after 28 days; 10-d window passed)

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information