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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:
1989-09-01 to 1989-10-05
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Version / remarks:
1982
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.6 (Degradation: Chemical Oxygen Demand)
Version / remarks:
1984
Deviations:
no
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: RZWI Nieuwgraaf in Duiven. The RZWI Nieuwgraaf in Duiven is an activated sludge plant treating predominantly domastic waste water.
- Laboratory culture: no
- Initial cell/biomass concentration: 2 mg DW/L
Duration of test (contact time):
28 d
Initial conc.:
2 mg/L
Based on:
test mat.
Initial conc.:
2.58 other: g O2/g
Based on:
ThOD
Remarks:
per L
Parameter followed for biodegradation estimation:
O2 consumption
Remarks:
The biodegradation was calculated as the ratio of the biochemical oxygen demand (BOD) to the theoretical oxygen demand (ThOD). The ThOD of the test substance (pure active ingredient) is 2.58 g O2/g test substance.
Details on study design:
TEST CONDITIONS
- Composition of medium: according to the guideline
- pH: 7.4 (end of the test)

TEST SYSTEM
- Culturing apparatus: 280 mL BOD (Biological Oxygen Demand) bottles
- Number of culture flasks/concentration: 2
- Stock solution: Sodium acetate was added to the bottle using stock solution of 1000 mg/L. For the application of the test substance on silica gel, a stock solution of 1000 mg/L in dichlormethane was added.

SAMPLING
- Sampling frequency: on day 0, 5, 15, 28

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes


Reference substance:
acetic acid, sodium salt
Key result
Parameter:
% degradation (O2 consumption)
Value:
65
Sampling time:
28 d
Details on results:
The biodegradation rate reached 65% at the end of the test period. Therefore, the test item should be classified as readily biodegradable in this Closed-Bottle-Test.
Results with reference substance:
The biodegradation of the positive control sodium acetate was 94 % on day 28.

Oxygen consumption (in mg O2/litre) after 5, 15 and 28 days:

- test substance: 5.1; 3.0; 3.4

- sodium acetate: 4.2; 4.6; 4.9

Percentages biodegradation (in % BOD/ThOD) after 5, 15, 28 days:

- test substance: 44; 58; 65

- sodium acetate: 81; 88; 94

The validity of the test is shown by the oxygen consumption in the control bottle with sodium acetate and and endogenous repiration of 0.4 mg/L. The pH of the medium at the end of the test period is 7.4.

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The ready biodegradability of the test item was assessed according to OECD guideline 301 D and EU-method C.6. The test item was biodegraded 65 % at day 28 in the Closed Bottle test. Therefore it can be concluded that the ditetradecyl peroxydicarbonate is readily biodegradable.
Executive summary:

A ready biodegradability test of ditetradecyl peroxydicarbonatewas performed which allows the biodegradability to be measured in an aerobic aqueous medium. The ready biodegradability was determined in the Closed Bottle test performed according to OECD guideline no. 301 . The biodegradation rate reached 65% at the end of the test period. Therefore, the test item should be classified as readily biodegradable in this Closed Bottle Test. The test is valid as shown by an endogenous respiration of 0.4 mg/L and by the mineralization of the reference compound, sodium acetate (94 %).

Description of key information

The ready biodegradability of the test item was assessed according to OECD guideline 301 D and EU-method C.6. The test item was biodegraded 65 % at day 28 in the Closed Bottle test. Therefore it can be concluded that the test item is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information

A ready biodegradability test of ditetradecyl peroxydicarbonatewas performed which allows the biodegradability to be measured in an aerobic aqueous medium. The ready biodegradability was determined in the Closed Bottle test performed according to OECD guideline no. 301 . The biodegradation rate reached 65% at the end of the test period. Therefore, the test item should be classified as readily biodegradable in this Closed Bottle Test. The test is valid as shown by an endogenous respiration of 0.4 mg/L and by the mineralization of the reference compound, sodium acetate (94 %).

Furthermore the biodegradability of the read-across substance was assessed according to OECD guideline 301 D. The test item was biodegraded by 68 % at day 28 in the Closed Bottle test. Over 60 % biodegradation was achieved in a period of less than 12 days immediately following the attainment of 10 % biodegradation. Hence the read across substance was classified as readily biodegradable, too.