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:
23 May - 20 Jun 2002
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
yes
Remarks:
Due to a malfunction of the cooling system on day 27 temperatures rose to a maximum of 45 °C on the last day of the test. This increase did not influence the overall test result.
Qualifier:
according to
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid

Study design

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): Activated sludge from the aeration tank of the sewage treatment plant Odenthal, Germany (date of collection: 21 May 2002)
- Pretreatment: none
- Concentration of sludge: 30 mg/L ss
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium: according to guideline
- Test temperature: 20 ± 1 °C
- pH: 7.5 (end of incubation); In one replicate the pH dropped to 5.9 due to malfunction of cooling apparatus
- pH adjusted: no
- Other: 25 mg test substance was weighed out on aluminium foil. This substance incl. aluminium foil was added to the test vessels.

TEST SYSTEM
- Culturing apparatus: Voith Sapromat (250 mL; continuously stirred)
- Number of culture flasks/concentration: 3
- Measuring equipment: BOD was continuously measured; NO2-N/NO2-N was analysed and the sum of both was determined by flow analysis (CFA and FIA) and spectrometric detection (EN ISO 13395)
- Test performed in closed vessels: yes

SAMPLING
- Sampling frequency: continuous analysis of BOD

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 3 bottles
- Abiotic sterile control: no
- Toxicity control: yes, 2 bottles
- Other: reference substance: yes, 3 bottles
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Parameter:
% degradation (O2 consumption)
Value:
28
Sampling time:
28 d
Remarks on result:
other: Mean of three replicates

BOD5 / COD results

Results with reference substance:
The reference substance was degraded to 85% after 14 d and 90% after 28 d.

Any other information on results incl. tables

Table 1: Degradation of the test item, reference substance and toxicity control during study period

Replicate

Day

4

6

8

12

14

18

20

22

26

28

 

 

Biodegradation of test item [%]

1

 

8

13

16

19

21

25

26

29

32

25

2

6

12

14

18

20

23

24

25

27

21

3

8

13

16

19

21

25

26

27

30

37

Mean

7

13

15

19

21

24

25

27

30

28

 

 

Biodegradation of reference item [%]

1

 

61

71

77

82

84

88

89

89

91

89

2

62

72

79

85

88

91

92

94

95

94

3

62

71

77

82

84

87

88

89

91

86

Mean

62

71

78

83

85

89

90

91

92

90

 

 

Biodegradation of toxicity control [%]

1

 

41

48

54

59

60

63

64

65

66

65

2

41

49

54

60

62

64

65

66

68

67

Mean

41

49

54

60

61

64

65

66

67

66

The BOD values on day 28 were corrected for the oxygen consumed by nitrification.

Table 2: Oxygen uptake by nitrification

 

Time

NO3-N [mg/L]

Oxygen uptake [mg/L]

NO2-N [mg/L]

Oxygen uptake [mg/L]

Test substance

0 h

< 1.00

4.57

< 0.10

0.34

Test substance

28 d

1.37

6.26

< 0.10

0.34

Oxygen uptake

28 d

-

1.69

-

0.00

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable