4,4'-methylenebis(2,6-diisopropylaniline)

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:

May - July 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, adapted

Details on inoculum:

- Source of inoculum/activated sludge: activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf
- Pretreatment: the sludge was filtrated, washed with tap water twice, then washed with and re-suspended in test medium. It was then aerated. The dry matter was determined with 3880 mg suspended solids/litre.
- Date of collection: 29th June 2007
- Batch no: 29062007
- Inoculum concentration: 25.9 mg/L
- Water filtered: yes

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

DOC

Details on study design:

- Flask volume: 1500 mL
- Controls: 2, containing mineral medium and inoculum
- Reference flasks: 2, containing reference item, mineral medium and inoculum
- Test flasks: 2, containing test item, mineral medium and inoculum
- Abiotic control: 1, containing test item, mineral medium and HgCI2
- Toxicity control: 1, containing test item, reference item, mineral medium and inoculum
- Temperature: 22 ± 2 °C
- Duration: 28 days

Reference substance:

aniline

Remarks:

a stock solution containing 2.1 g/L (nominal) in deionised water was prepared and its organic carbon content was measured with 1667 ppm, resulting in an organic carbon content of the reference item of 79.0 %.

Test performance:

The medium was prepared from the stock solutions. The inoculum was taken from its source, washed, aerated and the dry matter was determined. The test vessels were filled with medium and inoculum. Then all flasks were aerated for 72 hours with purified, CO2-free, moistened air to purge the system of CO2.The test was performed with a nominal start concentration of 20 mg organic carbon/L.
The following amounts of test item and reference item were added to the flasks:
- Lonzacure M-DIPA: 24.1-24.6 mg/L
- Aniline: 25.3 mg/L
Organic carbon was calculated to be 20 mg/L for reference 1 and 2, 19.6 and 20.0 mg/L for test vessels 1 and 2, 19.9 mg/L for abiotic control and 39.9 mg/L for toxicity control

Parameter:

% degradation (CO2 evolution)

Value:

-3.5

Sampling time:

2 d

Parameter:

% degradation (CO2 evolution)

Value:

-1.8

Sampling time:

6 d

Parameter:

% degradation (CO2 evolution)

Value:

-6.5

Sampling time:

14 d

Parameter:

% degradation (CO2 evolution)

Value:

-9

Sampling time:

23 d

Parameter:

% degradation (CO2 evolution)

Value:

-10.7

Sampling time:

29 d

Results with reference substance:

Day Degradation reference substance (mean %)
2 -1.1
6 81.6
14 83.2
23 88
29 85.2

Validity criteria fulfilled:

no

Remarks:

no 10-day-window could be identified and the pass level of 60 % given in the OECD guideline was missed

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test item is considered as "not readily biodegradable" . No biodegradalion was detected within 28 days. No 10-day-window could be identified and the pass level of 60% given in the OECD guideline was missed.

Executive summary:

The study was performed in order to evaluate aerobic elimination and degradation potential of the test item in a test for ready biodegradability, using a test item concentration of nominally 20 mg organic carbon/L (corresponding to 24.6 mg test item). The study was conducted in accordance with OECD guidelines no.301 B and EU testing methods C.4 C (CO2 -Evolution-Test / Modified STURM Test). Test duration was 28 days. The test item is considered as "not readily biodegradable" . No biodegradation was detected within 28 days. No 10-day-window could be identified and the pass level of 60% given in the OECD guideline was missed.

Description of key information

The study was performed in order to evaluate aerobic elimination and degradation potential of the test item in a test for ready biodegradability, using a test item concentration of nominally 20 mg organic carbon/L (corresponding to 24.6 mg test item). The study was conducted in accordance with OECD guidelines no.301 B and EU testing methods C.4 C (CO2 -Evolution-Test / Modified STURM Test). Test duration was 28 days. The test item is considered as "not readily biodegradable" . No biodegradation was detected within 28 days. No 10-day-window could be identified and the pass level of 60% given in the OECD guideline was missed.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Source: GLP-report