Glutamic acid

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

January 17 - February 14, 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study has been performed according to OECD guidelines and according to GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

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

Test material information

Constituent 1

Reference substance name:

Glutamic acid

EC Number:

200-293-7

EC Name:

Glutamic acid

Cas Number:

56-86-0

Molecular formula:

C5H9NO4

IUPAC Name:

glutamic acid

Details on test material:

- Name of test material (as cited in study report): L-Glutamic acid
- Physical state: White powder

- Stability under test conditions: no data available
- Storage condition of test material: 7 degrees C, protected form moisture and light

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Municipal sewage treatment plant,
D-31137, Hildesheim.
- Laboratory culture: no data available
- Method of cultivation: no data available
- Storage conditions: in aerobic condition by aeration
- Storage length: no data available
- Preparation of inoculum for exposure:
- Pretreatment: the activated sludge was filtered. The filtrate was maintained in aerobic condition by aeration until test begin.
- Concentration of sludge: no data available
- Initial cell/biomass concentration: colony forming units of the inoculum: ca. 10 exp5 CFU/ml
- Water filtered: no

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

Remarks:

, samples were taken on days 0, 1, 4, 7, 14, 21 and 28

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral nutrient solution acc. to OECD 301 E
- Additional substrate: no
- Solubilising agent (type and concentration if used): no data
- Test temperature: range 22 +/- 2 degrees C
- pH: range 7.4 +/- 0.1
- pH adjusted: yes, at test begin if necessary
- CEC (meq/100 g): no data
- Aeration of dilution water: no data
- Suspended solids concentration: no data
- 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 item concentration and for the inoculum control, one incubation vessel
for the reference item 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 inoculum
- Abiotic sterile control: no data
- Toxicity control: test and reference item in test concentration and inoculum

STATISTICAL METHODS:
No data available

Reference substance

Reference substance:

other: Sodium acetate, puriss (Fluka)

Results and discussion

Preliminary study:

No data

Test performance:

CARBON CONTENT OF THE TEST ITEM
The test item 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 item, the biodegradation came to 93% after 14 days. The biodegradation of the reference
item was not inhibited by the test item.

The test item in the test concentration of 50 mg/L reached the level o f10% (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

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:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test item L-glutamic acid must be regarded to be readily biodegradable in the 10-d-window.
After 28 days the biodegradation came to a maximum of 97%.