A mixture of: 2,4 -bis(N'-(4-methylphenyl)ureido)toluene; 2,6 -bis(N'-(4-methylphenyl)ureido)toluene

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:

9 September 1992 - 7 October 1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles. Limited information available to verify the composition of the used test substance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

(1981)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

A mixture of: 2,4 -bis(N'-(4-methylphenyl)ureido)toluene; 2,6 -bis(N'-(4-methylphenyl)ureido)toluene

EC Number:

411-070-0

EC Name:

A mixture of: 2,4 -bis(N'-(4-methylphenyl)ureido)toluene; 2,6 -bis(N'-(4-methylphenyl)ureido)toluene

Molecular formula:

C23H24N4O2

IUPAC Name:

3-(2-methyl-5-{[(4-methylphenyl)carbamoyl]amino}phenyl)-1-(4-methylphenyl)urea

Details on test material:

- Name of test material (as cited in study report): KY-ET
- Substance type: light yellow solid
- Physical state: solid
- Stability under test conditions: stable at least 48 hours in water
- Storage condition of test material: RT in the dark

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municiple sewage treatment plant Waterschap de Aa, Schijndel, The Netherlands
- Preparation of inoculum for exposure: The activated sludge was aerated for 4 hours aeration. After 0.5 hours settling, the supernatant was decanted to provide a significantly large volume for a 1% inoculum for each test flask

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

10 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

20 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Test temperature: The temperature varied between 18.5 and 21.5 degrees Celsius, except for day 0 when the medium temperature was 17 degrees Celsius
- pH: 4.8-5.5
- pH adjusted: no
- Continuous darkness: yes - brown vessels

TEST SYSTEM
- Number of culture flasks/concentration: 1
- Test performed in closed vessels due to significant volatility of test substance:
- Details of trap for CO2 and volatile organics if used: barium hydroxide (CO2 produced in each bottle reacted with the barium hydroxide in the gas scrubbing bottle and precipitated out as barium carbonate; amount of CO2 produced was determined by titrating the remaining Ba(OH)2 with 0.05 N standardized HCl.

SAMPLING
- Sampling frequency: d2, 5, 7, 9, 12, 16, 21 and 28

Reference substance

Reference substance:

other: sodium acetate

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (CO2 evolution)

Value:

13

Sampling time:

28 d

Remarks on result:

other: concentration 10 mg/l

% Degradation 2

Parameter:

% degradation (CO2 evolution)

Value:

6

Sampling time:

28 d

Remarks on result:

other: concentration 20 mg/L

Details on results:

Based on the calculated ThCO2 for the test substance, only 13% and 6% biodegradation, respectively for the low (10mg/L) and high (20 mg/L) nominal test concentrations, was observed. Therefore KY-ET was judged not readily biodegradable.

BOD5 / COD results

Results with reference substance:

The reference substance was biodegraded more than 60% (62%) within 12 days and was degraded to 97% by the end of the testing period (28d). The total CO2 release within the blank was 9.4 mg CO2.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: under test conditions little biodegradation observed

Conclusions:

Under the conditions of the test KY-ET was not readily biodegradable.

Executive summary:

A Modified Sturm Test (CO2 evolution) was performed according to OECD 301B. There were no protocol or other deviations and the data was judged reliable. The nominal concentrations of 10 mg/L and 20 mg/L showed only 13% and 9% degradation, respectively, via CO2 evolution. Therefore the test substance was judged not readily biodegradable.