2,2,4(or 2,4,4)-trimethylhexane-1,6-diamine

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:

1992-09-22 to 1992-10-20

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-A (Determination of the "Ready" Biodegradability - Dissolved Organic Carbon (DOC) Die-Away Test)

Version / remarks:

Cited as Directive 92/69/EEC, C.4-A

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

INOCULUM/TEST ORGANISM
- Sampling site: Municipal WWTP Marl-Ost, sampled 22 Sep 1992
- Preparation of inoculum: sampling, centrifugation (1100 g / 10 min), discard supernatant and resuspend with mineral medium, repeat centrifugation as above, resuspension of sludge (4.9 g dry weight/l), aeration through frit
- Initial cell concentration: 24.5 mg sludge/l

Duration of test (contact time):

28 d

Initial conc.:

9.93 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST SYSTEM
- Culturing apparatus: 2000 ml Erlenmeyer flask covered loosely with  aluminum sheet, filled with 900 ml test soln.
- Number of culture flasks per concentration: 2 with test substance (9.93 mg DOC/l) and inoculum; 2 with inoculum only; 2 with control substance 
(10.42 mg DOC/l) and inoculum;
- Aeration device: shaking for 28 days

SAMPLING: Days 0, 7, 14, 21, 27, 28

TEST CONDITIONS
- Composition of medium: 10 ml solution A + 1 ml solutions B-D per litre deionized water:  
A: 8.5 g KH2PO4, 21.75 g K2HPO4, 33.3 g Na2HPO4 x 2 H2O,  20.0 g (NH4)Cl 
B:  22.5 g MgSO4 x 7 H2O;  C: 27.5 g CaCl2;  D: 0.25 g FeCl3 x 6 H2O
- Test temperature: 21.8 - 22.1 degree C; dark

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (DOC removal)

Value:

7

Sampling time:

28 d

Details on results:

Kinetic of test substance (in %):
= 0 after 14 day(s)
= 0 after 27 day(s)

Degradation products: not measured

Results with reference substance:

Kinetic of control substance (in %):
= 99 after 7 day(s)

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable

Conclusions:

The test substance was determined as not readily biodegradable (7% biodegradation within 28 days)

Executive summary:

The biodegradability of the test item was examined in a "DOC-DIE AWAY"-test according to EU-Method C.4 -A (Hüls AG 1992). DOC removal was measured at weekly intervals over a period of 28 days. The test item was observed to be "not ready biodegradable" under the present test conditions (7% biodegradation within 28 days). The study was assessed as "reliable without restriction".

Description of key information

The biodegradability of the test item was examined in a "DOC-DIE AWAY"-test according to EU-Method C.4 -A. DOC removal was measured at weekly intervals over a period of 28 days. Other tests on biodegradability were conducted by Hüls AG 1979 and 1992. The test item was observed to be "not readily biodegradable" under the present test conditions (7% biodegradation within 28 days). 

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Additional information

The biodegradability of the substance was determined in several tests on ready and inherent biodegradation. The DOC die-away test showed that the test substance is not readily biodegradable. Other tests (Zahn-Wellens test, Closed Bottle test and Warburg test) support this finding (degradation rates between 1 and 13 %) and show that the test substance is neither readily nor inherently biodegradable.