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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:
Not reported
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:
no
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
Secondary (biological) activated sludge was obtained from the RWZI Horstermeer in Nederhorst den Berg, The Netherlands on January 13, 1993. The RWZI Horstermeer was an activated sludge plant treating predominantly domestic waste water. The dry weight of this inoculum appeared to be 4.0 mg/ml.
Duration of test (contact time):
28 d
Initial conc.:
20 mg/L
Based on:
test mat.
Initial conc.:
10 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
CO2 evolution
Reference substance:
acetic acid, sodium salt
Key result
Parameter:
% degradation (TOC removal)
Value:
ca. 60
Sampling time:
7 d
Remarks on result:
other: initial conc. 10 mg/l
Parameter:
% degradation (TOC removal)
Value:
ca. 84
Sampling time:
28 d
Remarks on result:
other: initial conc. 10 mg/l
Parameter:
% degradation (TOC removal)
Value:
ca. 42
Sampling time:
7 d
Remarks on result:
other: initial conc. 20 mg/l
Parameter:
% degradation (TOC removal)
Value:
ca. 56
Sampling time:
28 d
Remarks on result:
other: initial conc. 20 mg/l

Table 1: Results of the biodegradation test with CAPA 203 and sodium acetate. The results are expressed as CO2 mg (cumulative) formed after 7, 14, 21, 28 and 29 days (n=2)

Concentration

CAPA 203

(mg/l)

Concentration

Sodium acetate

(mg/l)

mg CO2 produced

7 days

14 days

21 days

28 days

29 days

 

 

 

 

 

 

 

0

100

44.0

56.9

60.8

59.4

59.8

20

100

37.6

61.5

71.4

73.1

72.9

10

0

28.6

35.7

38.6

40.0

40.2

20

0

39.9

50.8

52.4

53.2

53.2

Table 2: Percentage degradation of 100 mg/l sodium acetate, 20 mg/l CAPA 203 in the presence of 100 mg/l sodium acetate and CAPA 203 at a concentration of 10 and 20 mg/l

 

% biodegradation

7 days

14 days

21 days

28 days

29 days

 

 

 

 

 

 

sodium acetate (100 mg/l)

44

57

61

60

60

 

 

 

 

 

 

CAPA 203 (20 mg/l) in

the presence of sodium

acetate (100 mg/l)

-7

5

11

14

14

 

 

 

 

 

 

CAPA 203 (10 mg/l)

60

75

81

84

84

 

 

 

 

 

 

CAPA 203 (20 mg/l)

42

53

55

56

56

 

 

 

 

 

 

Table 3: Results of the biodegradability test

Concentration

CAPA 203

(mg/l)

Concentration

Sodium acetate

(mg/l)

mg CO2 of absorbed in the period

0-7

days

7-14

days

14-21

days

21-28

days

28-29

days

 

 

 

 

 

 

 

0

 

15.3

8.6

4.9

1.3

1.1

0

 

15.8

10.7

8.2

7.4

1.1

average

 

15.6

9.7

6.6

4.4

1.1

 

 

 

 

 

 

 

 

100

80.3

22.1

10.2

3.1

1.9

 

100

38.8

23.0

10.8

2.8

1.1

 

average

59.6

22.6

10.5

3.0

1.5

 

 

 

 

 

 

 

20

100

53.2

33.6

16.5

6.1

0.9

 

 

 

 

 

 

 

10

 

43.4

18.5

11.1

9.5

1.4

10

 

44.9

15.0

7.9

2.1

1.1

average

 

44.2

16.8

9.5

5.8

1.3

 

 

 

 

 

 

 

20

 

74.8

19.6

3.7

1.9

1.1

20

 

36.2

21.6

12.7

8.5

1.1

average

 

55.5

20.6

8.2

5.2

1.1

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The substance CAPA 203 was classified as readily biodegradable, having achieved 60% degradation within 7 days.
Executive summary:

A study was conducted to guideline OECD 301B using the substance CAPA 203. The reference compound (sodium acetate) degraded to 60% within 28 days. The total CO2-evolution in the inoculum blank at the end of the test was 37 mg, which was below the maximum acceptable amount according to the guideline (40 mg CO2L). The substance CAPA 203 was 60% degraded within 7 days when incubated at a concentration of 10 mg/L and 42% degraded when incubated at a concentration of 20 mg/L. On the basis of this result, CAPA 203 was classified as readily biodegradable.

Description of key information

One key study is presented. This study demonstrates that 2-oxepanone, polymer with 1,4-butanediol is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information

A reliable study was performed according to the OECD 301B guideline (Ready Biodegradability CO2 Evolution Test) using the test substance 2-oxepanone, polymer with 1,4-butanediol. Results showed 60% degradation of the test substance within 7 days when incubated at a concentration of 10 mg/L and 42% degradation when incubated at a concentration of 20 mg/L. On the basis of this result, the substance was classified as readily biodegradable.