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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:
1999-11-10 to 2000-01-05
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
GLP compliant study based on the Directive 92/69/EEC, C.4-E, 1992, the OECD No. 301 D, 1992 and the EPA Guideline 712-C-98-076: OPPTS 835.3110, 1998

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2000
Report date:
2000

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Version / remarks:
(July 17, 1992)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 835.3110 (Ready Biodegradability)
Version / remarks:
(January 1998)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)
Version / remarks:
(December 1992)
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
m-acetylphenyl acetate
EC Number:
219-524-8
EC Name:
m-acetylphenyl acetate
Cas Number:
2454-35-5
Molecular formula:
C10H10O3
IUPAC Name:
3-acetylphenyl acetate
Test material form:
solid
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Purity test date: October 19, 1999
- Lot/batch No.: 489

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature, light protection

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Final dilution of dissolved solid: 3.04 mg/L test substance (ThOD(NH4) = 6.0 mg O2/L)

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: domestic sewage treatment plant Groß-Zimmern, Germany
- Preparation of inoculum for exposure: activated sludge was centrifuged, decantated and solid material resuspended in tap water with a final centrifugation
- Pretreatment: suspension with water was aerated until use
- Concentration of sludge: 0.5 mL effluent/L
- Water filtered: no
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
3.04 mg/L
Based on:
test mat.
Initial conc.:
6 mg/L
Based on:
ThOD
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium: analytical grade salts were added to deionised water to give stock solutions. 1 mL of stock solutions were combined and filled to final volume of 1000 mL with deionised water. The test medium was aerated for 20 minutes and allowed to stand for about 20 hrs at the test temperature. Dissolved oxygen concentration was about 8.7 mg/L at about 20°C.
- Test temperature: 22°C
- pH: 7.5 - 7.6 (measured at the start of the test)
- Aeration of dilution water: yes (see above "composition of medium")
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Karlsruher flasks of 250 mL volume with glass stopper
- Number of culture flasks/concentration: 16 bottles containing: a) the test substance and inoculum, b) the reference compound Aniline and inoculum (positive control), c) only inoculum (inoculum control). 10 bottles containing test substance, reference compound Aniline and inoculum (toxicity control).
- Method used to create aerobic conditions: inoculum and medium solutions were sufficiently aerated prior to the start of the test.
- Measuring equipment: The oxygen concentrations were electrochemically measured in an airtight system with oxygen-electrode (WTW Oxi 340, Wissenschaftliche Technische Werkstätten GmbH, Weilheim, Germany) under constant stirring.
- Test performed in closed vessels: yes

SAMPLING
- Other: Oxygen measurements were performed in duplicate on days 0, 2, 5, 7, 12, 14, 21 and 28 (measurements of the toxicity control were done only on days 0, 7, 14, 21 and 28).

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes
- Other: Inoculum control (only inoculum)
Reference substance
Reference substance:
aniline

Results and discussion

% Degradationopen allclose all
Key result
Parameter:
% degradation (O2 consumption)
Value:
79
Sampling time:
28 d
Parameter:
% degradation (O2 consumption)
Value:
72
Sampling time:
10 d
Parameter:
% degradation (O2 consumption)
Value:
10
Sampling time:
2 d

BOD5 / COD results

Results with reference substance:
Degradability of the reference compound Aniline was sufficiently to the mean of 72 % after 14 days, and to 97 % after 28 days of incuation, thus confirming the suitablility of the used activated sludge inoculum.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
Based on a degradation of 79 % (O2 consumption) within 28 d and a degradation of 72 % within 10 d, the substance is readily biodegradable according to OECD criteria.
Executive summary:

Within the test period of 28 days, a degradation of 79 % was determined for the test substance in an OECD 301D test. Within the test period of 10 days, a degradation of 72 % was determined and the is assumed readily biodegradable.

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