p-benzoquinone

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:

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

Test material information

Constituent 1

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.