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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
15 Sep - 15 Oct 1999
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
yes
Remarks:
Day 5, two vessels: air flow fell to a minimum of 20 mL/min, which is slightly below the recommended 30 - 100 mL/min
Qualifier:
according to
Guideline:
EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)
Deviations:
yes
Remarks:
Day 5, two vessels: air flow fell to a minimum of 20 mL/min, which is slightly below the recommended 30 - 100 mL/min
GLP compliance:
yes
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): Oakley sewage treatment works
- Laboratory culture: no
- Preparation of inoculum for exposure: homogenisation, filtration through Whatman GFC filter paper
- Concentration of sludge: 30 mg suspended solids/L
Duration of test (contact time):
29 d
Initial conc.:
10 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Composition of medium: Mineral salts medium
- Test temperature: 21.3 - 23.6 °C
- pH: 7.5-7.7
- pH adjusted: no
- Aeration of dilution water: yes
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: 5 L glass culture bottles
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: bubbling with CO2-free air (30-100 mL/min)
- Test performed in closed vessels due to significant volatility of test substance: no
- Test performed in open system: yes
- Details of trap for CO2 and volatile organics if used: air outlet was connected to three Dreschel bottles in series, each containing 100 mL of 0.025 N of barium hydroxide


SAMPLING
- Sampling frequency: every second day
- Sampling method: 1st Dreschel bottle was disconnected and used for analysis; a fresh bottle was connected to the outlet at the end of the series


CONTROL AND BLANK SYSTEM
- Inoculum blank: bottles No. 1, 2
- Abiotic sterile control: no
- Toxicity control: bottle No. 6
- Other:
reference: bottle No. 3
test substance: bottles No. 4, 5


STATISTICAL METHODS: CO2/ThCO2

Reference substance:
benzoic acid, sodium salt
Key result
Parameter:
% degradation (CO2 evolution)
Value:
81
Sampling time:
29 d
Results with reference substance:
The reference substance sodium benzoate showed the expected biodegradation results (for details please see table below).

Sampling day

Degradation (% CO2/ThCO2)

Reference substance

Toxicity control

Test substance

Culture 1

Culture 2

Mean

2

19

23

1

1

1

4

54

54

28

27

28

6

65

63

40

39

40

8

72

-

49

48

49

10

76

-

57

55

56

12

79

-

62

59

61

14

80

-

67

64

66

19

82

-

77

73

75

24

82

-

82

78

80

28

83

-

82

79

81

29

83

-

82

79

81

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
Butane-1,3-diol is readily biodegradable as demonstrated in the Modified Sturm Test performed according to OECD 301B.
Executive summary:

The ready biodegradability of 1,3 -butanediol was studied in a Modfied Sturm Test following OECD 301B. The test substance was degraded to 81% (CO2/ThCO2) after 29 days. The 10 -days window was met. The validity criteria were fulfilled. 1,3 -Butanediol is readily biodegradable according to OECD criteria.

Description of key information

Readily biodegradable as demonstrated in OECD TG 301 B (Barnes, 2000). 

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

The ready biodegradability of 1,3 -butanediol was studied in a Modfied Sturm Test following OECD 301B. The test substance was degraded to 81% (CO2/ThCO2) after 29 days. The 10 -days window was met. The validity criteria were fulfilled. 1,3 -Butanediol is readily biodegradable according to OECD criteria (Barnes, 2000).