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Environmental fate & pathways

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:
1988
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: According to national standards (DIN 10707:1998-03)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report Date:
1989

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Qualifier:
equivalent or similar to
Guideline:
EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)
Qualifier:
according to
Guideline:
other: DIN EN ISO 10707
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- origin: sewage treatment plant at Frankfurt am Main, Sindlingen (domestic)
- type of inoculum: supernatant from settled domestic sewage sludge, no pre-treatment, not pre-adapted to the test or the reference substance
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
>= 2.58 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
- Test temperature: 20°C ± 1°C
- Culturing apparatus: 250 mL BOD bottles
- Sampling method: for each oxygen measurement a separate vessel was used. The vessels were not further incubated after they had been opened for one analysis
- Degradation analysis: at each sampling time the dissolved oxygen content was measured in 3 vessels.
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
7 d
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
14 d
Parameter:
% degradation (O2 consumption)
Value:
2
Sampling time:
21 d
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d

BOD5 / COD results

Results with reference substance:
The degradation of the reference substance sodium benozoate reached > 70 % in 7 days. Details see below.

Any other information on results incl. tables

Table 1: Results test substance

Time

O2-concentration [mg/L], mean values

 

 

 

Test substance

Control

O2-consumption

O2-consumption in [%] of the COD

0 d

8.57

8.58

0.01

0

7 d

8.53

8.29

-0.06

0

14 d

8.04

8.04

0.00

0

21 d

7.99

8.09

0.10

2

28 d

8.15

7.76

-0.39

0

Table 2: Results reference substance

Time

O2-concentration [mg/L], mean values

 

 

 

Reference substance

Control

O2-consumption

O2-consumption in [%] of the COD

0 d

8.83

8.58

-0.25

0

7 d

4.47

8.29

3.83

74

14 d

4.40

8.04

3.64

70

21 d

4.38

8.09

3.71

72

28 d

4.61

7.76

3.51

61

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test substance is not readily biodegradable.
Executive summary:

During a test period of 28 days no significant oxygen consumption could be noticed. Test revealed, that according to OECD 301D Guideline the test substance is not readily biodegradable.