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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: screening test, other
Remarks:
According to EN ISO 9888
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2001-04-26 to 2001-12-11
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods with acceptable restrictions
Qualifier:
according to guideline
Guideline:
other: EN ISO 9888
Version / remarks:
Zahn-Wellens-Test (similar to OECD 302 B)
GLP compliance:
no
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Source of activated sludge: Recirculation sludge from the industrial sewage treatment plant (DSM fine chemicals , Austria) and recirculation sludge from the communal (domestic) sewage treatment plant Welser Heide
- Pretreatment: Both sludges were mixed in a ratio of 1:1
- Concentration of sludge: 1g/L
Duration of test (contact time):
4 d
Initial conc.:
900 mg/L
Based on:
test mat.
Initial conc.:
436 mg/L
Based on:
other: TOC
Parameter followed for biodegradation estimation:
TOC removal
Details on study design:
TEST CONDITIONS
- Composition of medium: according to EN ISO 9888
- Test temperature: 24-22.5°C
- pH: no data.
- Suspended solids concentration: 1 g/L
- Continuous darkness: no data

TEST SYSTEM
- Number of culture flasks/concentration: 2 separate vessels for the test substance

SAMPLING
- Sampling frequency: day 0, 1, 2, and 4

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, one vessel
- Abiotic sterile control: yes, one vessel without sludge
- Positive control: yes, one vessel with sodium benzoate

Reference substance:
benzoic acid, sodium salt
Preliminary study:
not applicable
Parameter:
% degradation (TOC removal)
Value:
35
Sampling time:
1 d
Parameter:
% degradation (TOC removal)
Value:
98
Sampling time:
2 d
Key result
Parameter:
% degradation (TOC removal)
Value:
99
Sampling time:
4 d
Details on results:
For details on the test results please see table 1 under any other information on results incl. tables.
Results with reference substance:
The reference substance sodium benzoate was degraded to about 95 % within 4 days. 95 % degradation of the reference substance in 4 days indicates a valid result.

 

Table 1, degradation:

Date

day

Blank
(no test substance, just sludge)

Reference substance
(Na-benzoate)

Test substance,
vessel 1

Test substance,
vessel 2

Blank
(test substance without sludge)

Elimination vessel 1

Elimination vessel 2

Mean elimination vessel 1 and 2

 

 

 

mg TOC/L

          

(%)

2001-07-02

0

5

-

402

403

433

0

0

0

2001-07-03

1

9

256

265

267

405

36

35

35

2001-07-04

2

14

42

21

22

422

98

98

98

2001-07-06

4

12

23

17

12

384

99

100

99

 

Validity criteria fulfilled:
yes
Interpretation of results:
inherently biodegradable, fulfilling specific criteria
Conclusions:
Succinimide is inherently biodegradable in the static test within 4 days.
Executive summary:

A static test on the determination of the inherent aerobic biodegradation on succinimide was conducted applying a mix of activated sludge from the on-site STP and 50 % of the nearby municipal STP. The reference substance sodium benzoate was degraded by approx. 95 % in 4 days, indicating a valid test result. No abiotic elimination of succinimide was observed in the blank (test substance without sludge). The test substance succinimide reached a degradation of 99 % after 4 days, based on TOC removal.

Succinimide can therefore be considered as inherently biodegradable in the static test.

Description of key information

In a test to determine the aerobic biodegradation of succinimide (according to EN ISO 9888 - Zahn Wellens Test) the test item was degraded to 99 % after 4 days.

The applied sewage sludge was taken by 50 % from the on-site STP of DSM fine chemicals and by 50 % from the municipal STP.

The substance fulfills the criteria for being inherently biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
inherently biodegradable, fulfilling specific criteria
Type of water:
freshwater

Additional information