Perhydroimidazo[4,5-d]imidazole-2,5-dione

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:

1999

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:

yes (incl. QA statement)

Specific details on test material used for the study:

Chemical name: Tetrahydra-imidaza-(4,5-d)-imidazol-2,5-dion.
Batch number: Intermediate product from partie 692.
Date of manufacturing: 27 July 1998.
Purity: 97.6 % resp. 109.3 % based on elementary analysis of carbon and nitrogen respectively.
Impurities: 0.024% urea, 0.02% water.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial, non-adapted

Details on inoculum:

Activated sludge from laboratory wastewater plants treating municipal and synthetic sewage. Concentration of dry substance 30mg/L.

Duration of test (contact time):

35 d

Initial conc.:

ca. 59 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

Mixture of test substance, a defined inorganic medium and a non pre-adapted inoculum (activated sludge) are incubated and aerated at room temperature for up to 28 days. Samples were taken at regular intervals to determine the DOC concentration. In addition to the test substance the following tests were also caried out; blank values, biodegradation of a reference substance, inhibition of the inoculum by the test substance, abiotic elimination and adsorption onto the inoculum.

Reference substance:

aniline

Preliminary study:

TOC (mg/g): 329.
DOC (mg/g): 326.

Test performance:

Degradation degree of test substance after 14 days (% DOC): 90-100.
Degradation degree in the inhibition control after 14 days (% DOC): 50-60.
Physico-chemical (abiotic) elimination of the test substance (% DOC): <10 at the end of the test.
Elimination of the test substance by adsorption (% DOC): 10-20 after 5 days.

Parameter:

% degradation (DOC removal)

Value:

>= 100

Sampling time:

35 d

Details on results:

DOC decrease [%]:

Date Day RS IH PC AC TS1 · TS2 TSmv
10.09.98 0 0 0 0 0 0 I 0 0
11.09.98 1 -1 -1 10 -17 -18 ' -5 -12
13.09.98 3 0 2 15 12 9 8 9
15.09.98 5 98 51 9 10 -4 ' -4 -4
17.09.98 7 93 56 23 19 I 16 18
20.09.98 10 89 44 2 -10 1 -8 -9
24.09.98 14 90 50 2 -1 1 0
27.09.98 17 94 44 5 -2 -13 -8
01.10.98 21 96 51 7 5 I 12 9
04.10.98 24 95 54 5 23 I 26 25
07.10.98 27 99 61 14 36 43 40
08.10.98 28 95 64 19 48 54 51
11.10.98 31 96 82 -4 67' 86 77
14.10.98 34 101 100 -2 94 I 97 96
15.10.98 35 98 100 -1 106, 104 105

'
-Remarks: mv = mean value

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

Substance is inherently biodegradable but is not readably biodegradable according to the OECD guideline criteria.

Executive summary:

A study was carried out to determine the biodegradability of the test substance in the DOC (Die-Away Test) according to Annex of EEC-Directive 92/69 (July 1992), corresponding to OECD Guideline 301A (1993), and ISO Standard 7827 (1994). Mixtures of the test substance, a defined inorganic medium and activated sludge from laboratory wastewater plants treating municipal and synthetic sewage are incubated and aerated at room temperature for up to 28 days. Samples are taken at regular intervals to determine the DOC concentration. A 100% Biodegradation degree (DOC removal) was found after 35 days. And so, it was concluded that the test substance is biodegradable, but not readily biodegradable (according to OECD 301A criteria).

Description of key information

A standard DOC (Die Away Biodegradability) test was run according to the OECD 301A (1993), EEC 92/69 (July 1992) and ISO 7827 (1994), to determine the ultimate aerobic biodegradability of the test substance in water. By the end of the 35 days; 100% of the test substance has biodegraded. However, the substance did not completely degrade within the initial 28 days. Therefore, the substance can be classified as biodegradable but not readily biodegradable under the OECD 301A guideline criteria.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater