3-(dimethylamino)propylurea

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:

2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Principles of method if other than guideline:

In accordance with Japanese Industrial Standards (JIS) K 0102- 1998section 14.1

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

3-(dimethylamino)propylurea

EC Number:

401-950-2

EC Name:

3-(dimethylamino)propylurea

Cas Number:

31506-43-1

Molecular formula:

C6H15N3O

IUPAC Name:

[3-(dimethylamino)propyl]urea

Test material form:

liquid: viscous

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

Activated sludge sampling sites and date
Sampling sites:
On-site sludge sampling was carried out at the following 10 locations in Japan.
- Fushikogawa city sewage plant (Sapporo-shi, Hokkaido)
- Fukashiba industrial sewage plant (Kashima-gun, Ibaraki)
- Nakahama city sewage plant (Osaka-shi, Osaka)
- Ochiai city sewage plant (Shinjuku-ku, Tokyo)
- Kitakarni River (Ishinomaki-shi, Miyagi)
- Shinano River (Niigata-shi, Niigata)
- Yoshino River (Tokushima-shi, Tokushima)
- Lake Biwa (Otsu-shi, Shiga)
- Hiroshima Bay (Hiroshima-shi, Hiroshima)
- Dookai Bay (Kitakyushu-shi, Fukuoka)
Date March, 2002

Sludge sampling
City sewage
Return sludges from sewage plants were collected.
Rivers, lake and sea
Surface water and surface soil which was in contact with the atmosphere were collected.

Preparation of activated sludge
Activated sludge was prepared as follows to maintain its uniformity.
The filtrate (5 L) of the supernatant of the activated sludge cultivated about for 3 months was mixed with the mixed filtrate (5 L) of the supernatant of a sludge collected newly at each location. The mixed filtrate (10 L) was aerated after the pH value of the mixture was adjusted to 7.0 +/- 1.0.
The activated sludge cultivated the mixed filtrate (10 L) of the supernatant of sludge collected at the ten locations subject to cultivation as per below. Prefiltered open air was used.

Cultivation
Roughly 30 minutes after ceasing aeration of the sludge mixture, supernatant corresponding to about 1/3 of the whole volume was removed. Dechlorinated water was added to the remaining portion so that the total volume reached 10 L. This mixture was aerated, and then a predetermined amount of synthetic sewage was added to the mixture so that the concentration of the synthetic sewage was 0.1 wt% in the volume of dechlorinated water added. This procedure was repeated once every day. Cultivation was carried out at 25 +/- 2 °C.

Synthetic sewage
Glucose, peptone and potassium dihydrogenphosphate were dissolved in dechlorinated water to obtain 50 g/L of the solution for each component. The pH of the solution was adjusted to 7.0 +/- 1.0 with sodium hydroxide.

Control and use
During cultivation, the appearance of the supernatant, sedimentation of the sludge, formation of flock, pH, dissolved oxygen concentration in the solution and temperature were checked to maintain a normal state of sludge. It was confiied that these were within the scope of the control standard stipulated in the "Testing Methods for New Chemical Substances", and these results were stored as raw data. Microflora in the activated sludge was microscopically observed and sludge with no abnormal symptoms was used for the test.

Inspection of activity and date of initiation of use of activated sludge
Inspection of activity
Activity of the sludge was assessed using a reference item.
Date of initiation of use April 16, 2002

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

DOC removal

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

% Degradation 2

Parameter:

% degradation (TOC removal)

Value:

2

Sampling time:

28 d

% Degradation 3

Key result

Parameter:

% degradation (test mat. analysis)

Value:

1

Sampling time:

28 d

Details on results:

Results:
1) Percentagebiodegradation by BOD: 0 %, 3 %, 1 %, average 1 %
2) Percentage biodegradationby TOC: 2 %, 2 %, 3 %, average 2 %
3) Percentage biodegradation by HPLC 1 %, 1 %, 0 % average 1 %

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

A mixture of the reaction products (1-(3-(Dimethylamino)propyl)urea (CAS 31506-43-1, EC 401-950-2, monoDMAPAU) )and 1,3-bis[3-(dimethylamino)propyl]urea (CAS 52338-87-1, EC 257-861-2, bisDMAPAU) was tested in an OECD 301c modified MITI test for biodegradation. Under the present test conditions, the test item was not biodegraded.

Executive summary:

Under the present conditions, about theoretical amount of two components of the test item remained and average percentage biodegradation by BOD and TOC were 1 % and 2 %, respectively. The results indicate that the test item was neither biodegraded nor changed.