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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 1996 - January 1997
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: well documented GLP-guideline study
Reference:
Composition 0
Qualifier:
according to
Guideline:
EU Method C.4-B (Determination of the "Ready" Biodegradability - Modified OECD Screening Test)
GLP compliance:
yes
Test material information:
Composition 1
Oxygen conditions:
aerobic
Inoculum or test system:
sewage, predominantly domestic, non-adapted
Details on inoculum:
Effluent of laboratory scale unit receiving sewage from the south Wupper area water authority (predominantly domestic sewage).
Duration of test (contact time):
28 d
Initial conc.:
18.2 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
TEST CONDITIONS
- Test temperature: 22 +- 2 °C
- Concentration of stock solution of the sample: 1 g/l
- Initial concentration of the reference substance: 17.5 mg/l DOC
- Continuous darkness: yes

CONTROL AND BLANK SYSTEM
- Toxicity control: test and reference substance plus inoculum
Reference substance:
aniline
Preliminary study:
No information about a preliminary study are available.
Test performance:
The used concentrations of the test substance did not show toxic effects to bacteria.
By technical reasons no DOC-determination has been carried out at day 27. Therefore an additional DOC-determination has been carried out at day 29.
Parameter:
% degradation (DOC removal)
Value:
92
Sampling time:
7 d
Parameter:
% degradation (DOC removal)
Value:
94
Sampling time:
14 d
Parameter:
% degradation (DOC removal)
Value:
94
Sampling time:
21 d
Parameter:
% degradation (DOC removal)
Value:
96
Sampling time:
28 d
Details on results:
The test substance is considered to be "Readily Biodegradable".
Results with reference substance:
In parallel preparations with the reference substance aniline a degradation of 92 % was achieved within 14 days. All validity criteria of the test method were met.

test
substance
% degradation after n days
flask no. 0 h 7 d 14 d 21 d 28 d 29 d
8 0 88 90 95 98 99
9 0 96 97 92 94 98
mean 0 92 94 94 96 99
reference substance % degradation after n days
flask no. 0 h 7 d 14 d 21 d 28 d 29 d
3 0 100 89 95 97 96
4 0 98 95 94 95 96
mean 0 99 92 95 96 96
toxicity
control
% degradation after n days
flask no. 0 h 7 d 14 d 21 d 28 d 29 d
10 0 84 92 94 96 97
Validity criteria fulfilled:
yes
Remarks:
All validity criteria of the test method were met.
Interpretation of results:
readily biodegradable
Conclusions:
Within 28 days, a degradation of 96 % was determined for Lekutherm-Beschleuniger KU 6519 Neu. Lekutherm-Beschleuniger KU 6519 Neu has to be classified as "Readily Biodegradable".
Executive summary:

The biodegradability of the substance Lekutherm-Beschleuniger KU 6519 Neu was determined according to EU Method C.4-B (Determination of the "Ready" Biodegradability - Modified OECD Screening Test). The studiy was conducted in compliance with the Principles of Good Laboratory Practice (GLP).

The test substance is suspended in a mineral medium, inoculated with a mixed population of aquatic microorganisms and incubated for 28 days in the dark at 22 +- 2 °C. During this period, the biodegradation of the test substance is determined on the basis of the reduction in DOC. Within 28 days, a degradation of 96 % was determined for Lekutherm-Beschleuniger KU 6519 Neu. Lekutherm-Beschleuniger KU 6519 Neu has to be classified as "Readily Biodegradable".

In parallel preparations with the reference substance aniline a degradation of 92% was achieved within 14 days. All validity criteria of the test method were met.

Description of key information

Within 28 days, a degradation of 96 % was determined for Lekutherm-Beschleuniger KU 6519 Neu. Lekutherm-Beschleuniger KU 6519 Neu has to be classified as "Readily Biodegradable".

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

The biodegradability of the substance Lekutherm-Beschleuniger KU 6519 Neu was determined according to EU Method C.4-B (Determination of the "Ready" Biodegradability - Modified OECD Screening Test). The studiy was conducted in compliance with the Principles of Good Laboratory Practice (GLP).

The test substance is suspended in a mineral medium, inoculated with a mixed population of aquatic microorganisms and incubated for 28 days in the dark at 22 +- 2 °C. During this period, the biodegradation of the test substance is determined on the basis of the reduction in DOC. Within 28 days, a degradation of 96 % was determined for Lekutherm-Beschleuniger KU 6519 Neu. Lekutherm-Beschleuniger KU 6519 Neu has to be classified as "Readily Biodegradable".

In parallel preparations with the reference substance aniline a degradation of 92% was achieved within 14 days. All validity criteria of the test method were met.