Registration Dossier

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:
25 Nov - 24 Dec 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

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

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): Cambridge Sewage Treatment Works, Cowley Road, collected 24 Nov 2009
- Pretreatment: Sieved to 850 µm, settled, decanted and resuspended using mineral media. Centrifuged at ca. 4000 rpm for ca. 10 minutes discarded the supernatant, re-suspended and centrifuged again at ca. 4000 rpm for ca. 10 minutes and discarded the supernatant. Dry sludge solids determination was conducted on the pellet produced
- Dry sludge solids: 5.7%
- Volume of mineral medium: 1.5 L per bioreactor
- Dry sludge solids in test: 0.03 g/L
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
> 39.4 - < 39.5 mg/L
Based on:
test mat.
Initial conc.:
20 mg/L
Based on:
other: carbon
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST SYSTEM
- Culturing apparatus: 2000 mL flasks filled with 1500 mL test medium
- Number of culture flasks/concentration: 2
- Details of trap for CO2 and volatile organics if used: Atmospheric air was pumped into the test system and scrubbed clean of carbon dioxide by passing over soda lime. The air continued into the test vessel where it collets any evolved carbon dioxide before moving into the carbon dioxide traps, each containing 200 mL of 0.05 M sodium hydroxide solution
- Other: The test solutions were stirred for the duration of the study

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 flasks
- Reference: 2 flasks
- Toxicity control: 1 flask

Reference substance
Reference substance:
acetic acid, sodium salt

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (CO2 evolution)
Value:
0
Sampling time:
0 d
Parameter:
% degradation (CO2 evolution)
Value:
24
Sampling time:
5 d
Parameter:
% degradation (CO2 evolution)
Value:
50
Sampling time:
9 d
Parameter:
% degradation (CO2 evolution)
Value:
71
Sampling time:
14 d
Parameter:
% degradation (CO2 evolution)
Value:
87
Sampling time:
28 d

Any other information on results incl. tables

Table 1: Inorganic carbon (mg) in 200 mL NaOH

Time (days)

Blank

Reference

Test chemical

Toxicity control

1

2

1

2

1

2

2

2.52

2.54

10.82

9.24

4.01

3.44

14.00

5

2.17

2.06

8.17

8.09

9.25

7.21

13.17

7

1.13

1.05

3.49

3.73

5.35

5.03

6.23

9

0.94

0.80

2.76

2.81

4.10

5.84

5.38

14

1.62

1.48

4.54

5.44

6.97

8.77

9.85

19

0.85

0.84

2.49

2.61

3.73

3.78

5.12

23

0.63

0.51

2.00

2.14

2.17

2.29

3.81

28

1.24

0.59

1.42

2.06

1.26

1.46

2.15

29

0.65

1.84

1.69

2.30

1.17

0.33

1.48

29

2.56

1.47

3.13

2.44

1.60

1.24

6.33

Table 2: Cumulative inorganic carbon (mg) from test

Time (days)

Reference

Test chemical

Toxicity control

1

2

1

2

0

0.00

0.00

0.00

0.00

0.00

2

8.29

6.71

1.48

0.91

10.27

5

14.34

12.68

8.61

6.00

15.21

7

16.74

15.32

12.87

9.94

16.25

9

18.63

17.26

16.10

13.91

17.16

14

21.62

21.15

21.52

21.13

19.14

19

23.26

22.91

24.40

24.06

20.50

23

24.69

24.48

26.00

25.78

22.08

28

25.19

25.62

26.34

26.32

22.87

29

25.63

26.67

26.26

25.40

23.60

29

26.74

27.09

25.84

24.62

28.51

Table 3: Percentage degradation

Time (days)

Reference

Test chemical

Toxicity control

1

2

Mean

1

2

Mean

0

0

0

0

0

0

0

0

2

28

22

25

5

3

4

34

5

48

42

45

29

20

24

51

7

56

51

53

43

33

38

54

9

62

57

60

53

46

50

57

14

72

70

71

71

70

71

64

19

77

76

77

81

80

80

68

23

82

82

82

86

85

86

74

28

84

85

85

88

87

87

76

29

85

89

87

87

84

86

79

29

89

90

90

86

82

84

95

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable