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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:
21.03.2018 - 23.04.2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)
Deviations:
no
GLP compliance:
no
Remarks:
accredited by DAkkS

Test material

Constituent 1
Chemical structure
Reference substance name:
p-benzoquinone
EC Number:
203-405-2
EC Name:
p-benzoquinone
Cas Number:
106-51-4
Molecular formula:
C6H4O2
IUPAC Name:
1,4-benzoquinone
Test material form:
solid: particulate/powder

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, industrial, non-adapted
Duration of test (contact time):
28 d

Results and discussion

% Degradation
Key result
Parameter:
% degradation (DOC removal)
Value:
56
Sampling time:
28 d

Any other information on results incl. tables

Table 1: DOC-content of blank value-samples and samples with p-benzoquinone, calculated mean values and resulting difference as well as DOC-degradation within total test duration.       

test duration [d]

DOC [mg/l] p-benzoquinone-samples

DOC [mg/l] of blank samples

DOC-difference [mg/l]

DOC-degradation [%]

I

II

mean

I

II

mean

0

40,71

35,54

38,13

6,19

0,50

3,35

34,78

0

2

41,28

41,99

41,64

2,04

1,43

1,74

39,90

0

5

42,72

43,87

43,30

3,20

0,89

2,05

41,25

0

8

35,63

29,53

32,58

7,00

4,29

5,65

26,94

23

13

30,19

20,24

25,22

3,69

8,72

6,21

19,01

45

16

18,40

22,10

20,25

0,56

3,31

1,94

18,32

47

21

21,07

21,53

21,30

3,82

6,61

5,22

16,09

54

23

23,16

23,19

23,18

6,32

7,28

6,80

16,38

53

28

23,62

22,34

22,98

7,94

7,53

7,74

15,25

56

In day 2 and 5 the degree of DOC-degradation would be negative in purely arithmetical terms. This is due to a faster DOC-reduction in blank samples compared to test item samples. Hence, the degradation was set to 0.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
The reference samples biodegraded within 2 days to a degree of 76%. Abiotic control samples showed only a minimal DOC-degradation of 35 mg/l to 31 mg/l.
Interpretation of results:
not readily biodegradable
Conclusions:
p-Benzoquinone is not rapidly biodegradable as determined in a DOC Die-away test.
Executive summary:

As a criterion for the classification as rapidly biodegradable a DOC-elimination of 70% of the test item within a 10 day-window during a total test duration of 28 days is considered. The test samples of p-benzoquinone do not meet this criterion since only 56% DOC-elimination during the total test duration were attained. Hence, p-benzoquinone is classified as not rapidly biodegradable.