L-Aspartic acid, N,N'-1,2-ethanediylbis-, sodium salt (1:3)

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: sediment simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 6 March to 7 April 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 303 A (Simulation Test - Aerobic Sewage Treatment. A: Activated Sludge Units)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Directive 79/831/EEC (1987). Part C : Methods for the Determination of Ecotoxicity: Blodegradation Activated Sludge Simulation Tests.

Deviations:

no

GLP compliance:

yes

Radiolabelling:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: the inoculum used is activated sludge obtained from the aerators of the treatment plant of Bochott dealing predominantly with domestic sewage
- Concentration of sludge: 2.5 g/L
- Initial cell/biomass concentration: no data

Duration of test (contact time):

ca. 31 d

Initial conc.:

ca. 20 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Volume of test solution/treatment: trisodium EDDS was added in such a way that an influent concentration of 20 mg C/L was obtained.
- Composition of medium: water containing inoculum at about 2.5 g/L
- Additional substrate: no data
- Solubilising agent (type and concentration if used): water
- Test temperature: 18.1-21.7oC
- pH: 6.8-8.4
- pH adjusted: no
- CEC (meq/100 g): no data
- Aeration of dilution water: no
- Suspended solids concentration: 16.4 g/L
- Continuous darkness: no data
- Any indication of the test material adsorbing to the walls of the test apparatus: no data

TEST SYSTEM
- Culturing apparatus: the equipment consists of a storage vessel for the test substance stock solution, a storage vessel for the sewage influent, a dosing pump, an aeration vessel, a separator, an air-lift pump to recycle the activated sludge, and a vessel for collecting the treated effluent. The test material and the sewage are pumped separately to the aerator by means of two peristaltic pumps.
- Number of culture flasks/concentration: no data
- Method used to create aerobic conditions: air is blown Into the aeration vessel by a sintered aeration plate at the apex of the cone.
- Method used to create anaerobic conditions: not required
- Measuring equipment: no data

SAMPLING
- Sampling frequency:
Nutrient solution: sample for COD 2 times a week.
Effluent: samples for DOC analysis were taken 5 times a week. From day 14, additional 250 mL samples were taken 3 times a week for the sponsor to perform specific analysis if needed.
Mixed Liquor: 2 times a week.
- Sampling method: COD analysis of the nutrient solution was performed within 24 h after samplng. Effluent samples were analysed for DOC either immediately or stored in a refrigerator to be analysed the next day. The additional 250 mL samples were preserved with 3% formaldehyde 35% and stored In a freezer. The determination of suspended solids In the mixed Iiquor was performed immediately after sampling using Whatmann GF/C glass microflbre filters.
- Sterility check if applicable: no data
- Sample storage before analysis: samples were preserved with 3% formaldehyde 35% and stored In a freezer

STATISTICAL METHODS:
Mean, standard deviation and tolerance limits at 95% probablity level was performed on DOC removal results.

Compartment:

other: water / sediment, material (mass) balance

Remarks on result:

other: no data

% Degr.:

73.2

Parameter:

DOC removal

Sampling time:

1 d

% Degr.:

6.7

Parameter:

DOC removal

Sampling time:

4 d

% Degr.:

87.9

Parameter:

DOC removal

Sampling time:

7 d

% Degr.:

93.5

Parameter:

DOC removal

Sampling time:

11 d

% Degr.:

97.4

Parameter:

DOC removal

Sampling time:

14 d

% Degr.:

99.4

Parameter:

DOC removal

Sampling time:

18 d

% Degr.:

99.2

Parameter:

DOC removal

Sampling time:

21 d

% Degr.:

59.1

Parameter:

DOC removal

Sampling time:

25 d

% Degr.:

90.6

Parameter:

DOC removal

Sampling time:

28 d

% Degr.:

90.6

Parameter:

DOC removal

Sampling time:

30 d

Transformation products:

not measured

Evaporation of parent compound:

no

Volatile metabolites:

no

Residues:

no

Details on results:

TEST CONDITIONS
- Aerobicity, moisture, temperature and other experimental conditions maintained throughout the study: yes
- Anomalies or problems encountered (if yes): COD values of the nutrient solution were occasionally just outside the recommended range 350-400 mg/L.


MAJOR TRANSFORMATION PRODUCTS
- Range of maximum concentrations in % of the applied amount and day(s) of incubation when observed: no data
- Range of maximum concentrations in % of the applied amount at end of study period: no data



MINOR TRANSFORMATION PRODUCTS
- Range of maximum concentrations in % of the applied amount and day(s) of incubation when observed: no data
- Range of maximum concentrations in % of the applied amount at end of study period: no data


TOTAL UNIDENTIFIED RADIOACTIVITY (RANGE) OF APPLIED AMOUNT: no data


EXTRACTABLE RESIDUES
- % of applied amount at day 0: no data
- % of applied amount at end of study period: no data


NON-EXTRACTABLE RESIDUES
- % of applied amount at day 0: no data
- % of applied amount at end of study period: no data


MINERALISATION
- % of applied radioactivity present as CO2 at end of study: no data


VOLATILIZATION
- % of the applied radioactivity present as volatile organics at end of study: no data


STERILE TREATMENTS (if used)
- Transformation of the parent compound: no data
- Formation of transformation products: no data
- Formation of extractable and non-extractable residues: no data
- Volatilization: no data


RESULTS OF SUPPLEMENTARY EXPERIMENT (if any): no data

Table.1: Measured temperature, pH and DO (Dissolved oxygen) concentration in the mixed liquor

Date	Day of test	Control Unit			Test unit
		T (oC)	pH	DO (mg/L)	T (oC)	pH	DO (mg/L)
08/03/93	0	18.4	6.92	8.3	18.1	6.98	7.9
11/03/93	3	20.3	6.83	8.1	20.2	7.30	8.1
15/03/93	7	19.8	7.59	6.8	19.8	7.82	7.4
18/03/93	10	21.0	8.07	7.3	20.9	8.09	8.0
22/03/93	14	19.3	8.29	8.7	19.1	8.43	8.1
25/03/93	17	21.0	8.17	8.0	21.0	8.31	7.7
29/03/93	21	21.3	8.17	7.6	21.3	7.86	7.6
01/04/93	24	21.7	7.38	7.7	21.7	7.36	7.4
05/04/93	28	21.1	6.40	7.9	21.3	7.15	7.6

Table 2: COD values of the sewage

Date	Day of the test	COD (mg/L)
08-03-1993	0	310*
11-03-1993	3	295*
15-03-1993	7	388
19-03-1993	11	345
22-03-1993	14	360
24-03-1993	16	444*
26-03-1993	18	392
29-03-1993	21	348
01-04-1993	24	404
06-04-1993	29	368

* enrichment with synthetic sewage

Validity criteria fulfilled:

yes

Conclusions:

The biodegradation of trisodium EDDS was monitored in an activated sludge simulation test (DOC removal) conducted according to OECD Guideline 303 A and in compliance with GLP. The mean DOC removal value, based on 17 measurements taken between days 8-30 (with one result excluded) was 95.6% (SD 3.3%). Therefore, trisodium EDDS was shown to be readily biodegradable.

Executive summary:

In a GLP study conducted according to OECD Guideline 303 A, the biodegradation of trisodium EDDS was assessed in an activated sludge simulation test (DOC removal).

Raw, predominantly domestic, sewage from a municipal treatment facility was used (occasionally enriched with synthetic sewage) and DOC measured for about 31 days in a test unit (with test substance added at 20 mg C/L) and a control unit (receiving only the sewage inoculum). DOC concentrations were measured in both units and the difference was taken to reflect undegraded test material. The mean DOC removal value, based on 17 measurements taken between days 8-30 (with one result excluded) was 95.6% (SD 3.3%). Therefore, trisodium EDDS was shown to be readily biodegradable in this system.

Reference 2

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is readily biodegradable

Description of key information

The biodegradation of trisodium EDDS was assessed in an activated sludge simulation test (DOC removal) conducted according to OECD Guideline 303 A and in compliance with GLP.

The mean DOC removal value, based on 17 measurements taken between days 8-30 (with one result excluded) was 95.6% (SD 3.3%). Therefore, trisodium EDDS was shown to be readily biodegradable.

Additional information

In a GLP study conducted according to OECD Guideline 303 A, the biodegradation of trisodium EDDS was assessed in an activated sludge simulation test (DOC removal).

Raw, predominantly domestic sewage from a municipal treatment facility was used (occasionally enriched with synthetic sewage) and DOC measured for about 31 days in a test unit (with test substance added at 20 mg C/L) and a control unit (receiving only the sewage inoculum). DOC concentrations were measured in both units and the difference was taken to reflect undegraded test material. The mean DOC removal value, based on 17 measurements taken between days 8-30 (with one result excluded) was 95.6% (SD 3.3%). Therefore, trisodium EDDS was shown to be readily biodegradable in this system (Geukens, 1993b).