reaction product of diphenylmethanediisocyanate, toluenediisocyanate ( reaction mass of isomers: 65 % 2,4- and 35 % 2,6-diisocyanate), octylamine, oleylamine and 4-ethoxyaniline (molar ratio 3.88:1:6.38:0.47:2.91)

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:

1999-01-29 to 1999-06-30

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: supplied by the sewage plant Groß-Zimmern, Germany
- Method of cultivation: The activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was resuspended in tap water and again centrifuged. This procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 1.5 g dry material per litre were mixed with test water and then aerated until use.

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: in accordance to the guideline
- Test temperature: 22.2 - 22.3 °C
- pH: 7.4 - 7.6
- pH adjusted: no
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: flasks containing a volume of 500 mL
- Number of culture flasks/concentration:
two flasks containing test substance
two flasks containing inoculum control
one procedure control
one abiotic control
one toxicity control
- Measuring equipment:
Measurement of Oxygen: The change of pressure in the test flasks was measured by means of a manometric method (BSB/BOD-Sensor-System, Aqualytic, D-63263 Neu Isenburg, Germany) each day.
Temperature: Temperature was measured each working day in the climatic chamber.
pH-Value: pH-values were measured in all flasks at the start and end of the test using a pH-electrode ECM-Multi (Dr. Lange, D-40549 Düsseldorf, Germany).
- Details of trap for CO2 and volatile organics if used: Evolved carbon dioxide was absorbed in an aqueous solution (45 %) of potassium hydroxide.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Activated sludge at a concentration of 30 mg suspended solids per litre was filled up with test water to a volume of 244 mL. The inoculum control was also used for projects which run in parallel.
- Abiotic sterile control: 19.9 mg UREA 6 filled up with test water (sterile filtered, 0.2 - 0.45 µm filter) to a volume of 244 mL.
- Toxicity control: 10.1 mg UREA 6, 9.8 mg aniline and activated sludge at a concentration of 30 mg suspended solids per litre were filled up with test water to a volume of 244 mL.
- Procedure control: 25.3 rag Aniline and activated sludge at a concentration of 30 mg suspended solids per litre were filled up with test water to a volume of 244 mL. The procedure control was also used for other projects which ran in parallel.

Reference substance:

aniline

Test performance:

The amounts of test substance and reference compound were directly weighed into the test flasks. No emulsifiers or solvents were used, but the solutions were dispersed by stirring during the exposure period to achieve a homogeneous solution of the test substance. The closed test flasks were incubated in a climatic chamber under continuously stirring. The consumption of oxygen was determined by measuring the change of pressure in the flasks.

Key result

Parameter:

% degradation (O2 consumption)

Value:

14.25

Sampling time:

28 d

Remarks on result:

other: based on ThOD NH4

Details on results:

After correction of the mean biochemical oxygen demand of the inoculum controls at the end of the 28-day exposure period degradation rates of 13.0 % and 15.5 % were found based on a ThOD NH4 which is theoretically calculated, according to the molar ratio of the starting materials. If the calculation of biodegradation is based on ThOD NO3 percentage biodegradation reached 10.7 % and 12.8 % after 28 days of incubation.

Key result

Parameter:

BOD5

Value:

20 other: mgO2/L

Results with reference substance:

The reference compound aniline was sufficiently degraded to 96.0 % after 14 days, and to 100.0 % after 28 days of incubation.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test substance can not considered to be ready biodegradable.

Executive summary:

The test substance was investigated for its ready biodegradability in a Manometric Respirometry Test over a period of 28 days. The biodegradation was followed by the oxygen uptake of the micro organisms during exposure. As a reference compound aniline was tested simultaneously under the same conditions as the test substance, and functioned as a procedure control. After correction of the mean biochemical oxygen demand of the inoculum controls at the end of the 28-day exposure period degradation rates of 13.0 % and 15.5 % were found based on a ThOD NH4 which is theoretically calculated, according to the molar ratio of the starting materials. If the calculation of biodegradation is based on ThOD NO3 percentage biodegradation reached 10.7 % and 12.8 % after 28 days of incubation. The test substance can therefore not considered to be ready biodegradable. The reference compound aniline was sufficiently degraded to 96.0 % after 14 days, and to 100.0 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum. The biodegradation in the toxicity control containing both, the test substance and the reference compound aniline showed a similar course over the 28 days of exposure as the procedure control containing the reference compound aniline only. 43.8 % biodegradation was noted within 14 days and 54.1 % biodegradation was determined after 28 days of incubation. Thus, the test substance can be assumed to be not inhibitory on the activated sludge micro organisms.

Description of key information

The ready biodegradability of the test item was assessed over a 28 day period. The test material attained 14.25 % biodegradation after 28 days. Thus, the test item was classified not readily biodegradable under the conditions of the test.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

The test substance was investigated for its ready biodegradability in a Manometric Respirometry Test over a period of 28 days according to EU method C.4 D, OECD guideline 301 F and OPPTS-method 835.3110. The biodegradation was followed by the oxygen uptake of the micro organisms during exposure. As a reference compound aniline was tested simultaneously under the same conditions as the test substance, and functioned as a procedure control. After correction of the mean biochemical oxygen demand of the inoculum controls at the end of the 28-day exposure period degradation rates of 13.0 % and 15.5 % were found based on a ThOD NH4 which is theoretically calculated, according to the molar ratio of the starting materials. If the calculation of biodegradation is based on ThOD NO3 percentage biodegradation reached 10.7 % and 12.8 % after 28 days of incubation. The test substance can therefore not considered to be ready biodegradable. The reference compound aniline was sufficiently degraded to 96.0 % after 14 days, and to 100.0 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum. The biodegradation in the toxicity control containing both, the test substance and the reference compound aniline showed a similar course over the 28 days of exposure as the procedure control containing the reference compound aniline only. 43.8 % biodegradation was noted within 14 days and 54.1 % biodegradation was determined after 28 days of incubation. Thus, the test substance can be assumed to be not inhibitory on the activated sludge micro organisms.