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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:
1995-02-13 to 1995-06-28
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Certificate included in the report
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Domestic waste water treatment plant : ARA Ergolz II, Füllinsdorf, Switzerland
- Preparation of inoculum for exposure: The sludge was washed three times with tap water and an amount corresponding to 4g/L dry material (± 10%) was mixed with Sörensen buffer solution pH7 and then aerated prior to incubation. An amount of 0.5 mL sludge (filtered over cotton wool) was added to 1000 mL test medium.
Duration of test (contact time):
ca. 28 d
Initial conc.:
44 mg/L
Based on:
test mat.
Initial conc.:
>= 18.2 - <= 19 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
TEST CONDITIONS
- Composition of medium: according to OECD Guideline No. 301 E
- Test temperature: 19.7 - 21.5°C
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 2


SAMPLING
- Sampling frequency: day 0 (treatment day) , 7, 14, 21, 27 and 28
- Sampling method: Per sampling interval, two flasks of the samples containing the test article or the reference compound, one flask of the inoculum blank and one flask of the toxicity control were taken and analysed for DOC in triplicate.


CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: Aniline and the test compound were dissolved in the test medium at concentrations of 45 mg/L SP 703 and 26 mg/L aniline corresponding to an actually measured concentration of 39.3 mg DOC/L

Reference substance:
aniline
Preliminary study:
Test substance concentration was based on the DOC-values from a pre-test.
Parameter:
% degradation (DOC removal)
Value:
99
Sampling time:
28 d
Key result
Parameter:
% degradation (DOC removal)
Value:
95
Sampling time:
7 d
Results with reference substance:
The reference compound aniline reached complete biodegradation during the first seven exposure days. At the end of the test, aniline was readily biodegraded by an average of 95.1%.
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
Alpha-amylase was found to be readily biodegradable in the 'Modified OECD Screening Test' (OECD 301E).
Executive summary:

Alpha-amylase was tested for ready biodegradability in the '28 -day Modified OECD Screening Test'. The test was performed according to OECD 301E and in compliance with GLP.

The concentration of DOC (Disssolved Organic Carbon) in the test flasks containing alpha-amylase decreased by an average of 95.0 %, 92.5 % and 93.8% within 7, 14 and 21 days of exposure, respectively. At the end of the test (day 28), alpha-amylase was biodegraded by an average of 99.0%. Consequently, alpha-amylase was found to be readily biodegradable.

The reference compound Aniline reached complete biodegradation during the first seven exposure days. At the end of the test (day 28) Aniline was readily biodegraded by an average of 95.1%.

Description of key information

Alpha-amylase was found to be readily biodegradable in the 'Modified OECD Screening Test' (OECD 301E).

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Alpha-amylase was tested for ready biodegradability in the '28 -day Modified OECD Screening Test'. The test was performed according to OECD 301E and in compliance with GLP.

The concentration of DOC (Dissolved Organic Carbon) in the test flasks containing alpha-amylase decreased by an average of 95.0 %, 92.5 % and 93.8% within 7, 14 and 21 days of exposure, respectively. At the end of the test (day 28), alpha-amylase was biodegraded by an average of 99.0%. Consequently, alpha-amylase was found to be readily biodegradable.