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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: screening test, other
Remarks:
Pre-guideline study; method: other: original Zahn-Wellens test (see reference 2) and 3)). Comparable to OECD test guideline 302 B (Zahn-Wellens/EMPA Test)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Pre-guideline, but comparable to guideline study. Detailed study report not available
Principles of method if other than guideline:
Pre-guideline study; method: other: original Zahn-Wellens test (see reference 2) and 3)). Comparable to OECD test guideline 302 B (Zahn-Wellens/EMPA Test)
GLP compliance:
no
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: source of inoculum/activated sludge unknown
- Preparation of inoculum for exposure: centrifugation for 5 min at 2000 R/min
- Pretreatment: no data
- Concentration of sludge in test medium: 1 g dry substance/L (ca. 12 g wet sludge after centrifugation for 2 L reaction medium)
- Water filtered: no, tap water
Duration of test (contact time):
10 d
Initial conc.:
ca. 1 000 mg/L
Based on:
COD
Parameter followed for biodegradation estimation:
other: COD
Details on study design:
TEST CONDITIONS
- Composition of medium: mineral medium: 215 mg urea (alternatively 385 mg NH4Cl) and 89 mg NaH2PO4 x H2O in 2 L of water
- Additional substrate: no
- Solubilising agent (type and concentration if used): no
- Test temperature: 22 ± 3°C
- pH: 6.5 - 7.5
- pH adjusted: if necessary
- Aeration of dilution water: yes
- Suspended solids concentration: 1 g dry substance (activated sludge)/L
- Continuous darkness: no data

TEST SYSTEM
- Culturing apparatus: 4 L cylindric glas vessel (beaker)
- Number of culture flasks/concentration: 1
- Method used to create aerobic conditions: stirring and introduction of compressed air passed through a cotton wool strainer and a wash-bottle
- Measuring equipment: COD or TOC analyser
- Test performed in closed vessels due to significant volatility of test substance: no data
- Test performed in open system: no data

SAMPLING
- Sampling frequency: daily or appropriate timepoints
- Sampling method: withdrawal of sample from test vessel and filtration of sample through paper filter (Schleicher und Schüll, Blauband Nr. 589) washed three times with distilled water

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
Reference substance:
not specified
Parameter:
other: COD
Value:
> 95
Sampling time:
10 d
Parameter:
other: COD
Value:
88
Sampling time:
5 d
Validity criteria fulfilled:
not specified
Interpretation of results:
readily biodegradable
Conclusions:
Isobutylamine undergoes > 95% biodegration within 10 days based on determination of COD (Zahn-Wellens test). The pass levels for ready biodegradability (70% degradation, 10 d window) are met.
Executive summary:

Isobutylamine was tested for biodegradability in a pre-guideline test following the original method of Zahn-Wellens. Test realization ist reported with no specific details, but the general procedure followed is described in reference 2. The test method is comparable to OECD test guideline 302 B (Zahn-Wellens/EMPA Test).

 

Non-adapted activated sludge of a sewage treatment plant served as inoculum. Test substance was incubated for 10 days at 22°C. No parallels were set up. Samples were analyzed for COD at different time points.

 

After 10 days isobutylamine was degraded to > 95% (day 5: 88%). Pass levels for ready biodegradability are met.

 

In a Zahn-Wellens test for biodegradability, isobutylamine was shown to be readily biodgradable (Hoechst AG, 1977).

 

This biodegradability study is classified as acceptable. The method used is comparable to OECD test guideline 302 B (Zahn-Wellens/EMPA Test) with minor restrictions (no duplicates, different test medium, restricted reporting).

Description of key information

Isobutylamine was tested for biodegradability in a pre-guideline test following the original method of Zahn-Wellens. Test realization ist reported with no specific details, but the general procedure followed is described in reference 2. The test method is comparable to OECD test guideline 302 B (Zahn-Wellens/EMPA Test).

 Non-adapted activated sludge of a sewage treatment plant served as inoculum. Test substance was incubated for 10 days at 22°C. No parallels were set up. Samples were analyzed for COD at different time points.

 

After 10 days isobutylamine was degraded to > 95% (day 5: 88%). Pass levels for ready biodegradability are met.

 

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information