2-imino-1-methylimidazolidin-4-one

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

21.11.2002 - 02.12.2002

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

other: DIN EN ISO 9 888, replaces DIN EN 29 888

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: sewage treatment plant Trostberg
- Method of cultivation: aerobic cultivation, dry solids: 4.9 g/L

Duration of test (contact time):

11 d

Initial conc.:

953 mg/L

Based on:

test mat.

Initial conc.:

ca. 460 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: activated sludge, nutrient medium, deionized water
- Additional substrate: nutrient medium (according to DIN EN 9888)
- Test temperature: 20-25°C
- pH adjusted: yes (to pH 7 +/- 0.5 if required)

TEST SYSTEM
- Culturing apparatus: brown glass vessels (2 L)
- Number of culture flasks/concentration: 1
- Method used to create aerobic conditions: aeration and agitation

SAMPLING
- Sampling frequency: at least every 4 days

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes (1 replicate)
- Abiotic sterile control: yes (HgCl2 added, 1 replicate)

Reference substance:

other: no reference substance used

Preliminary study:

Not applicable.

Test performance:

No unusual observations during test affecting results.

Parameter:

% degradation (DOC removal)

Value:

93

Sampling time:

11 d

Details on results:

No further details reported.

Results with reference substance:

Not applicable, no reference substance tested.

Table 2: DOC removal [%]

Date	Day	DOC removal [%]
		Test vessel a	Test vessel b	Control vessel
21.11.2002	0.125
22.11.2002	1	5	8	64
25.11.2002	4	84	4	85
28.11.2002	7	93	-	94
02.12.2002	11	88	3	100

Validity criteria fulfilled:

not applicable

Remarks:

no test results with reference substance available (e.g. aniline, ethylene glycol)

Interpretation of results:

readily biodegradable

Conclusions:

Creatinine is readily biodegradable under the conditions of the test.

Executive summary:

Creatinine was tested for its biodegradability according to the German Guideline DIN EN ISO 9888 which is similiar to OECD 302 B (Zahn-Wellens-Test) at an initial concentration of ca. 460 mg DOC/L at a temperature of 20 -25 °C for 11 days. Biodegradation was followed by measurements of DOC removal.

Under the conditions of the test, 93 % degradation could be observed after 11 days. Also the biodegradation was within the 10 day window and therefore Creatinine is regarded as readily biodegradable.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04.10.2005 - 21.12.2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

Qualifier:

according to guideline

Guideline:

EU Method C.4-B (Determination of the "Ready" Biodegradability - Modified OECD Screening Test)

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Water solubility (under test conditions): 90 g/L (20 °C)
- Stability of test material at room temperature: stable

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Details on inoculum:

Inoculum from the effluent of the sewage treatment works A-2500 Baden, which waste-water catchment is predominantly domestic, was collected. On arrival in the laboratory, the sample was aerated by means of filtered compressed air for about 45 minutes before used for the study.
The inoculum was not acclimatised or adapted to Creatinine before exposure to the test substance in this study.

Duration of test (contact time):

28 d

Initial conc.:

40 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: see "any other information on material and methods"
- Test temperature: 22.0 +/- 0.6 °C.
- pH: 6.26 - 7.56
- pH adjusted: no
- Continuous darkness: yes

Reference substance:

benzoic acid, sodium salt

Preliminary study:

no data

Test performance:

see "any other information on materials and methods"

Key result

Parameter:

% degradation (DOC removal)

Value:

96.1

Sampling time:

28 d

Details on results:

see "any other information on results"

Results with reference substance:

The plateau of biodegradation was reached on Day 2 and the degradation of the positive control substance sodium benzoate exceeded the pass level of 70 % within 14 days.

Blank corrected data of the DOC determination is presented in table 2 and percentage biodegradation is listed in table 3.

Table 2: Blank-corrected DOCs (mg/L)

Day	test substance		positive control PK5	toxicity control TK6
	A3	A4
0	40.01	39.33	20.74	58.94
2	39.83	39.69	1.52	40.81
4	12.73	12.68	1.15	13.24
7	11.84	12.99	0.89	11.03
10	11.98	13.00	1.19	10.36
14	10.57	11.31	0.48	8.81
17	10.23	10.73	1.26	8.37
21	2.44	8.94	1.22	2.12
24	1.88	1.53	1.08	2.08
28	1.92	1.22	0.57	1.52

Table 3: Percentage biodegradation

Day	Test substance		mean	positive control PK5	toxicity control TK6
	A3	A4
0	0	0	0	0	0
2	0.46	-0.91	-0.23	92.67	30.76
4	68.18	67.77	67.98	94.46	77.54
7	70.41	66.98	68.69	95.70	81.29
10	70.05	66.95	68.50	94.24	82.42
14	73.59	71.24	72.42	97.71	85.06
17	74.44	72.73	73.58	93.92	85.80
21	93.91	77.27	85.59	94.12	96.41
24	95.31	96.12	95.72	94.81	96.48
28	95.20	96.90	96.05	97.25	97.42

1) Test substance

Creatinine degraded by 96.1 % within 28 days. The degradation occurred within a 10 -d window as defined by the Guidelines. The 10 -d window started at about Day 3. 70 % degradation was exceeded at approx. Day 13, i.e. within the 10 -d window.

2) Positive control

The plateau of biodegradation was reached on Day 2 and the degradation of the positive control substance sodium benzoate exceeded the pass level of 70 % within 14 days.

3) Toxicity control

Degradation in the toxicity control, which contained sodium benzoate and the test substance, was not indicative of an inhibition of the microbial activity by the test substance.

4) Abiotic degradation

On Day 0, the DOC concentration was between 40.58 and 40.61 mg/L and on Day 28 between 39.58 and 39.46 mg/L, therefore no significant degradation to inorganic carbon occured in the abiotic sterile control.

5) Adsorption control

On Day 0, the DOC concentration was between 40.37 and 42.29 mg/L and on Day 28 between 39 .08 and 39.63 mg/L, therefore no adsorption of the test substance to the inoculum occured.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test substance Creatinine with a nominal concentration of 40 mg DOC/L was degraded by 96.1 % after 28 days of incubation at 22 +/- 0.6 °C. The biodegradation occured within a 10-d window according to the Guideline. Therefore Creatinine can be classified as readily biodegradable.

Executive summary:

The ready biodegradability of Creatinine was determined by the measurement of DOC (dissolved organic carbon) at frequent intervals over a 28 day period. The methode used was that described in Part C.4-B of the EC Commission Directive 92/69/EEC and in the OECD Guideline 301 E.

The reference substance sodium benzoate was degraded by 97.7 % within 14 days. Degradation in the toxicity control, which contained sodium benzoate and the test substance, was not indicative of an inhibition of the microbial activity by the test substance. The test substance Creatinine with a nominal concentration of 40 mg DOC/L was degraded by 96.1 % after 28 days of incubation at 22 +/- 0.6 °C. The biodegradation occured within a 10-d window according to the Guidelines.

According to the Guidelines a substance giving a result greater than 70 % loss of DOC in a 10 -d window within 28 days is regarded as readily biodegradable. Therefore Creatinine can be classified as readily biodegradable.

Description of key information

Two tests were performed to assess the biodegradability of Creatinine.

The first methode used was that described in Part C.4-B of the EC Commission Directive 92/69/EEC and in the OECD Guideline 301 E.

The second was according to the German Guideline DIN EN ISO 9888 which is similiar to OECD 302 B (Zahn-Wellens-Test).

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Two tests were performed to assess the biodegradability of Creatinine. The first methode used was that described in Part C.4-B of the EC Commission Directive 92/69/EEC and in the OECD Guideline 301 E. The second was according to the German Guideline DIN EN ISO 9888 which is similiar to OECD 302 B (Zahn-Wellens-Test).

In the first test Creatinine (with a nominal concentration of 40 mg DOC/L) was degraded by 96.1 % after 28 days of incubation at 22 +/- 0.6 °C. Under the conditions of the second test 93 % degradation could be observed after 11 days. Also the biodegradation occured within a 10-d window according to the Guideline and therefore Creatinine is regarded as readily biodegradable.