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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:
30 September 1998 to 28 October 1998
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted to EU test guidance in compliance with GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report date:
1998

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)
Deviations:
no
GLP compliance:
yes

Test material

Constituent 1
Details on test material:
Batch number: HI-295
Purity: 94.7 %
Solubility in water< 0.5 g/l
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not applicable.

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
Type: mixed population of aquatic micro-organisms (activated sludge)
Origin: secondary effluent of a domestic sewage treatment plant (Klaranlage Odenthal)
Date of collection: 25.09.1998
Pre-treatment: none
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
3.3 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
Test substance
Name of test substance: T-9601
Remarks: direct weighing
Initial concentration: 3.3 ± 0.2 mg/l test substance

Reference substance
Name of reference substance: Aniline
Purity: at least 99.5 %
Initial concentration: 2.0 mg/l reference substance

Inoculum
Source of sewage effluent: secondary effluent of a domestic sewage treatment plant (Klaranlage Odenthal)
Treatment given: separation of coarse particles by filtration
Concentration of effluents in reaction mixture: 5ml/I (SOP 2030-6600102-96 D)
Preconditioning: aeration for 5 days

Study conditions
Duration: 28 days
Test temperature: 20 ± 1 °C
Reference substance
Reference substance:
aniline

Results and discussion

Preliminary study:
Not conducted.
Test performance:
The test performed in accordance with the specifications detailed within the guideline.
% Degradation
Parameter:
% degradation (O2 consumption)
Value:
1
Sampling time:
28 d
Details on results:
The substance achieved only 1% biodegradation within 28-days, and cannot be considered as readily biodegradable.

BOD5 / COD results

Results with reference substance:
In parallel preparations with the reference substance aniline a degradation of 66 % was achieved within 14 days.

Any other information on results incl. tables

Oxygen measurement

Test substance: T-9601

Reference substance: Aniline

 

Dissolved oxygen of blank inoculum: (mg O2 after x days)

Bottle No.

0 days

Bottle No.

7 days

Bottle No.

14 days

Bottle No.

21 days

Bottle No.

28 days

1

9.40

3

8.93

5

8.83

7

8.86

9

8.81

2

9.39

4

9.10

6

9.02

8

9.00

10

8.79

Mean

9.40

 

9.02

 

8.93

 

8.93

 

8.80

 

Dissolved oxygen of reference substance: (mg O2 after x days)

Bottle No.

0 days

Bottle No.

7 days

Bottle No.

14 days

Bottle No.

21 days

Bottle No.

28 days

11

9.41

13

6.81

15

5.86

17

5.33

19

4.75

12

9.40

14

6.71

16

5.66

18

5.32

20

4.94

Mean

9.41

 

6.76

 

5.76

 

5.33

 

4.85

 

Dissolved oxygen of test substance: (mg O2/l after x days)

Bottle No.

0 days

Bottle No.

7 days

Bottle No.

14 days

Bottle No.

21 days

Bottle No.

28 days

41

9.36

43

8.94

45

8.90

47

8.86

49

8.79

42

9.34

44

8.99

46

8.97

48

8.84

50

8.68

Mean

9.35

 

8.97

 

8.94

 

8.85

 

8.72

 

Dissolved oxygen of toxicity control: (mg O2/l after x days)

Bottle No.

0 days

Bottle No.

7 days

Bottle No.

14 days

Bottle No.

21 days

Bottle No.

28 days

51

9.33

53

6.05

55

5.53

57

4.88

59

5.04

52

9.33

54

6.54

56

5.48

58

5.01

60

5.11

Mean

9.33

 

6.30

 

5.50

 

4.95

 

5.08

 

Results – DO depletion: % Degradation

 

Test substance

Test concentration: 3.3 ± 0.2 mg/l

ThOD: 1827 mg/g

COD: ---mg/g

DO depletion after n days [mg/l]

7 d

14 d

21 d

28 d

No. 1: (mt0 – mtx) – (mb0 – mbx)

0.04

0.00

0.03

0.00

No. 2: (mt0 – mtx) – (mb0 – mbx)

0.00

0.00

0.03

0.06

D1: % Degradation

1

0

0

0

D2: % Degradation

0

0

0

1

D, Mean

1

0

0

1

 

Reference substance

Test concentration: 2.0 mg/l

ThOD: 2409 mg/g

COD: --- mg/g

DO depletion after n days [mg/l]

7 d

14 d

21 d

28 d

No 1: (mt0 – mtx) – (mb0 – mbx)

2.22

3.08

3.61

4.06

No. 2: (mt0 – mtx) – (mb0 – mbx)

2.31

3.27

3.61

3.86

D1: % Degradation

46

64

75

84

D2: % Degradation

48

68

75

80

D, Mean

47

66

75

82

 

* Toxicity control

DO depletion after n days [mg/l]

7 d

14 d

21 d

28 d

No.1: (mt0 – mtx) – (mb0 – mbx)

2.90

3.34

3.98

3.69

No.2: (mt0 – mtx) – (mb0 – mbx)

2.41

3.38

3.85

3.62

D1: % Degradation

27

31

37

34

D2: % Degradation

22

31

35

33

D, Mean

25

31

36

34

Comments: * In the toxicity control 3.3 ± 0.2 mg/l test substance and 2.0 mg/l reference substance were used. The ThOD values were respectively COD values of these substances are shown in the tables above.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
Within the test period of 28 days, a degradation of 1 % was determined for T-9601

T-9601 has to be classified as "Not Readily Biodegradable".
Executive summary:

Study conducted to procedure: Biodegradability - Closed Bottle Test Method according to Council Directive 92/69 EEC, Method C.4-E., in compliance with GLP.

 

The test substance is suspended in a mineral medium, inoculated with a mixed population of aquatic microorganisms and incubated for 28 days under aerobic conditions in the dark at 20 ± 1°C.During this period, the biodegradation of the test substance is determined on the basis of the reduction of dissolved oxygen.

 

Within the test period of 28 days, a degradation of1% was determined for T-9601

 

T-9601 has to be classified as "Not Readily Biodegradable".

 

Comments relevant to result: The validity criteria mentioned in the laboratories SOP number 2030-6600102-96 D were met.

 

In parallel preparations with the reference substance aniline a degradation of 66 % was achieved within 14 days.