Glutamic acid

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

Guideline:

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

GLP compliance:

yes (incl. QA statement)

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.

% Degradation

% Degradation 1

Parameter:

% degradation (DOC removal)

Value:

0

Sampling time:

1 d

% Degradation 2

Parameter:

% degradation (DOC removal)

Value:

90

Sampling time:

4 d

% Degradation 3

Parameter:

% degradation (DOC removal)

Value:

92

Sampling time:

7 d

% Degradation 4

Parameter:

% degradation (DOC removal)

Value:

95

Sampling time:

14 d

% Degradation 5

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.