2-methylhydroquinone

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19.02.2018 - 21.03.2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)

Deviations:

no

GLP compliance:

no

Remarks:

accredited by DAkkS

Specific details on test material used for the study:

The test item is methylhydroquinone (CAS-No.: 95-71-6) with a purity of >99 %.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial, non-adapted

Duration of test (contact time):

28 d

Key result

Parameter:

% degradation (DOC removal)

Value:

33

Sampling time:

28 d

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

test duration [d]	DOC [mg/l] of methylhydroquinone samples			DOC [mg/l] blank samples			DOC-difference [mg/l]	Degradation DOC[%]
	I	II	mean	I	II	mean
0	52,00	56,75	54,38	9,40	8,99	9,20	45,18	0
2	44,60	46,03	45,32	1,80	2,82	2,31	43,01	5
5	46,42	44,47	45,45	4,49	3,97	4,23	41,22	9
7	45,86	45,17	45,52	4,92	6,13	5,53	39,99	11
9	46,77	44,88	45,83	5,74	5,44	5,59	40,24	11
12	41,81	45,11	43,46	7,25	9,27	8,26	35,20	22
16	34,78	37,56	36,17	< 0,50	< 0,50	< 0,50	35,67	21
19	35,94	39,42	37,68	< 0,50	4,96	2,73	34,95	23
21	35,25	39,47	37,36	3,64	4,34	3,99	33,37	26
23	35,69	33,03	34,36	< 0,50	5,57	3,04	31,33	31
26	32,71	27,58	30,15	< 0,50	< 0,50	< 0,50	29,65	34
28	34,88	29,46	32,17	2,34	1,54	1,94	30,23	33

       

Validity criteria fulfilled:

yes

Remarks:

The reference samples biodegraded within 5 days to a degree of 88%. Abiotic control samples showed no DOC-degradation.

Interpretation of results:

not readily biodegradable

Conclusions:

Methylhydroquinone is not rapidly biodegradable.

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 methylhydroquinone do not meet this criterion since only 33% DOC-elimination during the total test duration were attained. Hence, methylhydroquinone is classified as not rapidly biodegradable.

Description of key information

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 methylhydroquinone do not meet this criterion since only 33% DOC-elimination during the total test duration were attained. Hence, methylhydroquinone is classified as not rapidly biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater