3-methyl-1,1-diphenylurea

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:

02.02.-06.03.2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, non-adapted

Details on inoculum:

INOCULUMThe inoculum contained a mixed population of microorganisms obtained from the secondary effluent of the waste water treatment plant of Pardubice processing predominantly municipal sewage.PREPARATION OF INOCOLUMThe fresh collected waste water was filtered through paper filter. COD was determined and waste water was aerated till using.Justification of the test systemThe inoculum preparation is in conformity with the recommendations of the test guideline.

Duration of test (contact time):

0 - 28 d

Initial conc.:

3.41 mg/L

Based on:

COD

Details on study design:

TEST CONDITIONSThe mineral medium was strongly aerated for 20 minute and let standing for 20 hours at the test temperature. The volume of waste water for the inoculation of mineral medium was chosen 2.0 mL per 1 L of medium (COD of waste water: 73 mg.L-1). 30 L aerated mineral medium was prepared for the test and before the beginning of the test it was inoculated with 60 mL of modified waste water. - pH: 7.4-Temperature: 20 ± 1.0 °C -Illumination: no illumination, in the dark-Exposition time: 28 daysTEST SYSTEM-2 x 9 bottles with test substance and inoculated medium-2 x 9 bottles with reference substance and inoculated medium for the check of inoculum activity-9 bottles with test substance and inoculated medium for the determination of oxidized nitrogen forms-2 x 5 bottles with test and reference substance mixture and inoculated medium for the toxicity test-2 x 9 bottles with inoculated medium only for the blank determinationCONTROL AND BLANK SYSTEM- Inoculum blank: yes, the inoculated mineral medium- Toxicity control: yes, the test substance and refence substance mixturedMEASUREMENTAt the 3rd, 7th, 10th, 14th, 17th, 21st, 24th and 28th day of test the appropriate bottles from each series were taken off and they were analysed for dissolved oxygen.

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

8.5

Sampling time:

28 d

Key result

Parameter:

COD

Value:

1.173 other: mg.mg-1

Key result

Parameter:

BOD5

Value:

0.01 other: mg.mg-1

Results with reference substance:

COD of the reference substance: 1.637 mg.mg-1, biodegradation 78.5 % after 28 days

Table No.: 4          Biodegradation of test and reference substance in the main test

	Formula for calculation of biodegradation		Biodegradation (%) after period (days)
			0	3	7	10	14	17	21	24	28
Test substance		1	0	2.8	4.8	4.5	5.4	6.6	9.2	9.2	8.9
		2	0	1.9	4.0	4.5	4.8	5.1	9.2	9.2	8.1
		average	0	2.3	4.4	4.5	5.1	5.9	9.2	9.2	8.5
Reference substance		1	0	56.8	65.0	62.9	66.7	73.1	76.9	78.1	78.1
		2	0	56.8	63.2	62.9	65.8	73.1	77.8	78.1	78.9
		average	0	56.8	64.1	62.9	66.3	73.1	77.3	78.1	78.5

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

COD of the reference substance: 1.637 mg.mg-1

Executive summary:

The test substance,Akardit,was tested forthe ready biological degradability in Closed Bottle Test.

The test was performed according to:

Method C.4E - Closed Bottle Test, Council Regulation (EC) No. 440/2008, published in O.J.L 142, 2008.

 

The results of biological degradation are related to experimentally determined COD values
of test and reference substance at the beginning of the test.

The test substance was sufficiently soluble in used mineral medium so the dosage from the stock solution was carried out.

Sodium benzoate was used as the reference substance. The dosage was carried out from the stock solution.

COD of the test substance in medium at the beginning of the main test:  3.41 mg·L^-1

COD of reference substance in medium at the beginning of the main test: 3.44 mg·L^-1

In parallel to the main test the toxicity test was performed.

Based on the test substance contains nitrogen inthe chemical composition,the oxidized nitrogen forms were determined and the correction for nitrification was carried out.

The test was performed at temperature of 20 ± 1 °C with the pH values of solutions 7-8
at the beginning of the test.

 

Validity of test

The prescribed validity criteria in the test were fulfilled.

The test substance was not inhibiting for the used inoculum.

Since all criteria of acceptability were met, this study is considered to be valid.

 

Test results

In this 28-day study of ready biological degradability the degradation of 8.5 % of the test substance, Akardit,was attained in the end of study.

Description of key information

The test substance, Akardit, was tested for the ready biological degradability in Closed Bottle Test. The test was performed according to method Method C.4E - Closed Bottle Test, Council Regulation (EC) No. 440/2008, published in O.J.L 142, 2008.

Only one study is available.

GLP study.

Klimish score 1.

In this28-day study of ready biological degradabilitythe degradation of 8.5 % of the test substance,Akardit,was attained in the end of study.The test substance Akardit is not ready biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed