L-Glutamine, L-alanyl-

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1994-02-28 to 1994-03-18

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

Version / remarks:

adopted 17 July 1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Remarks:

Supernatant of activated sludge was used.

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Activated sludge was taken from a municipal STP at Taunusstein-Bleidenstadt, Germany
- Pretreatment: Supernatant was filtered through coarse paper filter and the first 200 mL were discarded.
- Storage conditions: The supernatant was stored aerobic until use on the same day of pre-treatment.

Duration of test (contact time):

16 d

Initial conc.:

40 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: mineral nutrient solution accroding to OECD guideline
- Additional substrate: no
- Test temperature: 20.0 - 23.7 °C (mean: 22.07 °C)
- pH: 6.87 - 8.03
- pH adjusted: yes, once in both test solutions
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 2 vessels
- Method used to create aerobic conditions: aeration with filtered compressed air and agitation with a magnetic stirrer
- Measuring equipment: DOC-analyzer: LiquiTOC, Foss-Heraeus
- Test performed in open system: yes

SAMPLING
- Sampling frequency: at days 0, 2, 3, 6, 9, 13 and 16

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 2 vessels
- Abiotic sterile control: no
- Toxicity control: no
- Positive control: yes, 2 vessels

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (DOC removal)

Value:

97

Sampling time:

16 d

Parameter:

% degradation (DOC removal)

Value:

95

Sampling time:

13 d

Parameter:

% degradation (DOC removal)

Value:

92

Sampling time:

9 d

Parameter:

% degradation (DOC removal)

Value:

93

Sampling time:

6 d

Results with reference substance:

Degradation rate of sodium benzoate: 99% after 13 days.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The final degradation value after a test period of 16 d was 97%. The control substance was degraded to 99% within 13 days. From the data obtained the test material can be regarded as readily biodegradable.

Description of key information

Readily biodegradable: 97% after 16 d (OECD 301 E)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The ready biodegradability of the substance was investigated in a study conducted according to OECD guideline 301 E (GLP). Activated sludge from a municipal sewage treatment plant was used and the degradation rate was determined by measuring the removal of dissolved organic carbon (DOC) in the test medium. After an incubation period of 16 days, a degradation rate of 97% based on DOC removal was recorded. The 10-day window criterion was met. Due to the high degradation rate the study period was shortened to 16 instead of 28 d. Based on the results, the substance is considered to be readily biodegradable according to OECD criteria.