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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
other: SIDS
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data

Data source

Reference
Reference Type:
publication
Title:
SIDS for L-Glutamic acid
Author:
OECD
Year:
2013
Report Date:
2013

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)
GLP compliance:
yes (incl. certificate)

Test material

Specific details on test material used for the study:
- Name of test material (as cited in study report): L-Glutamic acid
- Physical state: White powder
- Storage condition of test material: 7 degrees C, protected form moisture and light

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
50 mg/L
Based on:
formulation
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
[TEST CONDITIONS]
- Composition of medium: Mineral nutrient solution according to OECD 301 E
- Additional substrate: no
- Test temperature: 22 +/- 2 degrees C
- pH: 7.4 +/- 0.1
- pH adjusted: yes, at test begin if necessary
- Continuous darkness: yes

[TEST SYSTEM]
- Culturing apparatus: the vessels were stirred continuously with magnetic bars
- Number of culture flasks/concentration: two incubation vessels for the test substance concentration and for the inoculum control, one incubation vessel for the reference substance and for the toxicity control
- Method used to create aerobic conditions: by aeration
- Measuring equipment: pH-meter (Corning Ph240), DOC-Analysator (Multi N/C 3000, Analytik Jena), Thermohygrograph (Lufft)
- Test performed in closed vessels due to significant volatility of test substance: no
- Test performed in open system: yes

[SAMPLING]
- Sampling frequency: samples were taken on day 0, 1, 4, 7, 14, 21 and 28
- Sampling method: no data- Sterility check if applicable: no- Sample storage before analysis: no data

[CONTROL AND BLANK SYSTEM]
- Inoculum blank: nutrient solution and inoculums
- Abiotic sterile control: no data
- Toxicity control: test and reference item in test concentration and inoculum
Reference substance
Reference substance:
other: Sodium acetate, puriss.

Results and discussion

Test performance:
[CARBON CONTENT OF THE TEST SUBSTANCE]
The test substance was added at a test concentration of 50 mg/L corresponding to a carbon content of 20.4 mg C/L in the test vessels.

[COURSE OF THE BIODEGRADATION]
The total amount of DOC was analysed in seven measurements over a period of 28 days.
In the toxicity control containing both test and reference substance, the biodegradation came to 93% after 14 days. The biodegradation of the reference substance was not inhibited by the test substance.The test substance in the test concentration of 50 mg/L reached the level of 10% (begin of the biodegradation) after 1 day. In the 10-d-window a biodegradation rate > 70% was reached. After 28 days the biodegradation came to a maximum of 97%.The validity criteria of the test are fulfilled according to the guideline.
% Degradationopen allclose all
Parameter:
% degradation (DOC removal)
Value:
0
Sampling time:
1 d
Parameter:
% degradation (DOC removal)
Value:
90
Sampling time:
4 d
Parameter:
% degradation (DOC removal)
Value:
92
Sampling time:
7 d
Parameter:
% degradation (DOC removal)
Value:
95
Sampling time:
14 d
Key result
Parameter:
% degradation (DOC removal)
Value:
97
Sampling time:
28 d

BOD5 / COD results

Results with reference substance:
In order to check the activity of the test system sodium acetate in a concentration of 130 mg/L was used as functional control. The adaptation phase changed after 1 day into the degradation phase (degradation >= 10%). The course of the degradation phase was rapid and reached a degradation rate of 96% already on day 14. The quality criterion degradation >= 70% after 14 days was fulfilled.

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Interpretation of results:
readily biodegradable
Conclusions:
The biodegradation of L-glutamic acid measured by DOC removal was 97% after 28 days. L-glutamic acid is considered to be readily biodegradable.