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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report date:
2008

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
EPA OPPTS 835.3120 (Sealed Vessel Carbon Dioxide Production Test)
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Ethyl difluoroacetate
EC Number:
207-223-4
EC Name:
Ethyl difluoroacetate
Cas Number:
454-31-9
Molecular formula:
C4H6F2O2
IUPAC Name:
ethyl difluoroacetate
Details on test material:
- Name of test material (as cited in study report): Ethyl difluoroacetate
- Physical state: liquid / colorless, clear
- Analytical purity: 99.9%
- Batch No.: 33244/106 A
- Storage condition of test material: Storage at refrigerator, avoid temperatures >70 °C

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: municipal activated sludge from the wastewater treatment plant of the city Mannheim, Germany
- Preparation of inoculum for exposure: A suitable aliquot of the activated sludge suspension was sieved by a finely woven mesh with a mesh size about 1 mm. After settling the supernatant was discarded and the sludge suspension was filled up with tap water. This suspension was pre-aerated for about 24 hours at room temperature. The sludge of the suspension was adjusted to a concentration 800 mg/L of dry weight and then added to the
test vessels to obtain a sludge concentration of 4 mg/L dry substance.
- Concentration of sludge: 4 mg/L dry substance

Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
52 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
TOC removal
Details on study design:
TEST CONDITIONS
- Composition of medium: 160 ml (aqueous phase) containing 4.4 µl (52.0 mg/L) test substance, 90 ml mineral medium, 0.5 ml (800 mg/L dry matter) inoculum, 9.5 ml water
- Test temperature: 22 ± 2 °C
- pH: 7.4 ± 0.2
- pH adjusted: no

TEST SYSTEM
- Culturing apparatus: 160 ml incubation bottles filled up to a volume of 100 ml closed with butyl rubber septa gas tight
and shaken
- Number of culture flask
- 23 blank control assays
- 23 test substance assays
- 23 inhibition control test assays
- 14 reference substance assays
- 5 assays for abiotic control

SAMPLING
- Sampling frequency: at Day 3, 7, 10, 14, 21, 28

Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Parameter:
% degradation (TOC removal)
Value:
40 - 50
Sampling time:
28 d
Details on results:
- Duration of the adaptation phase: 2 days
- Elimination of the test substance at physical chemical control at the end of exposure (%TIC/TOC): < 10
- Degradation degree in the inhibition control after 14 days (% TIC/TOC): 48

BOD5 / COD results

Results with reference substance:
- Degradation degree of the reference substance after 14 days (% TIC/TOC): 60%

Applicant's summary and conclusion

Interpretation of results:
other: partly/moderately biodegradable