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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Nov. 18, 2002-Dec. 19, 2002
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report Date:
2002

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Marl-Ost municipal sewage treatment plant
- Initial cell/biomass concentration: 3.94 g/l dry matter
Duration of test (contact time):
29 d
Initial test substance concentration
Initial conc.:
34.3 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Test temperature: 19.7-21.9 degree C
- pH: 7.4-7.5
- Aeration of dilution water: yes, overnight
- Suspended solids concentration: 26.3 mg/L

TEST SYSTEM
- Culturing apparatus: 5000 ml Woullf flasks
- Number of culture flasks/concentration: 2 flasks

SAMPLING
- Sampling frequency: 0, 2, 5, 9, 12, 14, 21, 28, and 29 days

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 flasks

STATISTICAL METHODS: Results were calculated using the EXCEL computer program.
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
85
Sampling time:
29 d
Details on results:
The test substance was 85% degraded on day 29.

BOD5 / COD results

Results with reference substance:
The reference substance was 89% degraded in 29 days.

Any other information on results incl. tables

% Degradation

Test Duration (days)

Sodium Benzoate

Test Vessel 1

Test Vessel 2

Test Vessel Mean

0

0

0

-1

-1

2

32

1

-5

-2

5

59

24

19

22

9

76

57

46

52

12

84

73

66

70

14

84

72

67

70

21

93

76

79

78

28

95

86

80

83

29

89

84

85

85

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The test substance was 85% degraded in 29 days, and is considered readily biodegradable.
Executive summary:

This study examined the biodegradability of the test substance. 34.3 mg/L of test substance was added to flasks containing activated sludge. The amount of CO2 evolved was then measured over the next 29 days. Sodium benzoate was used as a reference substance. The reference substance was 89% degraded in 29 days. Therefore the test is valid. The test substance was 85% degraded in 29 days. The test substance is readily biodegradable.