1,3-Cyclohexanedimethanamine, N1,N3-bis(2-methylpropylidene)-

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:

2011-03-17 to 2011-04-14

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle 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: sewage plant for domestic sewage in Balatonfüred, Hungary
- Preparation of inoculum for exposure: The activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was re-suspended in isotonic saline solution 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 5 g dry material per litre was mixed with reconstituted water and then aerated until use (in this study 100 mL inoculum was prepared). Before use the sludge was filtered through cotton wool.

Duration of test (contact time):

28 d

Initial conc.:

2 mg/L

Based on:

test mat.

Initial conc.:

6.66 other: mg/mg

Based on:

ThOD/L

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 °C
- pH: 7.27
- pH adjusted: no

TEST SYSTEM
- Culturing apparatus: Winkler bottles (300 mL, coded) with special neck and glass stoppers.
- Number of culture flasks/concentration:
10 (+2 reserve) bottles containing the test item and inoculum
10 (+2 reserve) bottles containing the reference item and inoculum (procedure control)
10 (+2 reserve) bottles containing only inoculum (inoculum control)
10 (+2 reserve) bottles containing the test item, reference item and inoculum (toxicity control)

Reference substance:

benzoic acid, sodium salt

Test performance:

The test item was exposed to activated sludge from the aeration tank of a domestic waste water treatment plant for 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item Sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

Key result

Parameter:

% degradation (O2 consumption)

Value:

5.9

Sampling time:

28 d

Details on results:

Correction for oxygen uptake for interference with nitrification:
Because of the N-containing test item, the oxidised nitrogen (nitrate and nitrite) concentrations were determined after each oxygen measurement with photometric method using nitrite and nitrate cell tests. The LOQ of the measurements was 0.03 mg NO2/mL and 0.4 mg NO3/mL, respectively. The measured quantity of nitrite was below the LOQ in the measured samples on the days 0, 7, 14 and 21 and was in the measurable range in the second parallel vessel of the inoculum control (0.64 mg/L) and in the first parallel vessel of the toxicity control (0.12 mg/L). The measured quantity of nitrate was below the LOQ in the measured samples on the days 0, 7, 14 and 21 and was in the measurable range in the second parallel vessel of the inoculum control (0.8 mg/L).
Percentage Biodegradation:
Under the test conditions the percentage biodegradation of Incorez 397 reached a mean of 5.9 % after 28 days based on ThODNO3.

Key result

Parameter:

BOD5

Value:

> 0.38 other: mgO2/mg test item

Results with reference substance:

The reference item Sodium benzoate was sufficiently degraded to a mean of 69.7 % after 14 days, and to a mean of 73.8 % after 28 days of incubation, based on ThODNH4. The percentage biodegradation of the reference item confirms the suitability of the used activated sludge inoculum.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Correction for oxygen uptake for interference with nitrification:
The measured dissolved oxygen concentrations were not in accordance with the obtained nitrite and nitrate concentrations on the 28th day of the experiment, furthermore the appearance of the relatively high oxidised nitrogen concentrations was occasionally, unique (nitrite or nitrate was not detected in the second parallel vessels of each group and the nitrite and nitrate appeared on the 28th day only), therefore, the calculated BOD values were not corrected for nitrification.
Percentage Biodegradation:
The test item can be considered to be not ready biodegradable. According to the test guidelines the pass level for ready biodegradability is removal of 60 % ThODNO3.

Executive summary:

The purpose of this study was to determine the ready biodegradability of the test item Incorez 397. The test item was exposed to activated sludge from the aeration tank of a domestic waste water treatment plant for 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item Sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. Under the test conditions the percentage biodegradation of Incorez 397 reached a mean of 5.9 % after 28 days based on ThODNO3. Therefore the test item can be considered to be not ready biodegradable. The reference item Sodium benzoate was sufficiently degraded to a mean of 69.7 % after 14 days, and to a mean of 73.8 % after 28 days of incubation, based on ThODNH4, thus confirming the suitability of the used activated sludge inoculum. In the toxicity control containing both, the test item and the reference item, a mean of 28.3 % biodegradation was noted within 14 days and 33.8 % biodegradation after 28 days of incubation. Thus, the test item can be assumed to not inhibit the activated sludge microorganisms.

Description of key information

Incorez 397 was assessed in a closed bottle test in accordance to OECD guideline 301 D and EU method C.4 VI. The test item was exposed to activated sludge from an aeration tank for 28 days. Under the test conditions the percentage biodegradation of Incorez 397 reached a mean of 5.9 % based on ThODNO3. Thus, Incorez 397 was not ready biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

The purpose of this study was to determine the ready biodegradability of the test item Incorez 397. The test item was exposed to activated sludge from the aeration tank of a domestic waste water treatment plant for 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item Sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. Under the test conditions the percentage biodegradation of Incorez 397 reached a mean of 5.9 % after 28 days based on ThODNO3. Therefore the test item can be considered to be not ready biodegradable. The reference item Sodium benzoate was sufficiently degraded to a mean of 69.7 % after 14 days, and to a mean of 73.8 % after 28 days of incubation, based on ThODNH4, thus confirming the suitability of the used activated sludge inoculum. In the toxicity control containing both, the test item and the reference item, a mean of 28.3 % biodegradation was noted within 14 days and 33.8 % biodegradation after 28 days of incubation. Thus, the test item can be assumed to not inhibit the activated sludge microorganisms.