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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
GLP compliance:
yes (incl. certificate)
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, adapted
Details on inoculum:
The inoculum was prepared from a secondary effluent obtained from Peppers Ferry Wastewater Treatment Plant (Blacksburg, Virginia). Effluent was preconditioned
for 7 days prior to use, by aerating at 20 °C.
Duration of test (contact time):
28 d
Initial conc.:
5 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
Test Bottle Preparation
1. Mineral medium was aerated for 20 minutes and allowed to stand for 20
hours prior to use. Dissolved oxygen was measured after this period.
2. Mineral medium was added to a large flask to approximately one third full
(the inoculum blank, or IB). Then, appropriate amounts of test substance
and reference substance were added to separate large flasks to make 5g
test substance per liter of mineral medium in the final solution (the test
solution, or TS), and 2g reference substance per liter of mineral medium in
the final solution (the procedure control, or PC).
3. Appropriate amounts of test substance and reference substance were added
to a fourth large flask to make up a treatment with a final solution
concentration of 5g test substance and 2g reference substance per liter of
mineral medium (the toxicity control, or TC).
4. Finally, inoculum was added to all flasks.
5. There were 10 bottles prepared with the inoculum blank, 10 bottles with
the test solution, 10 with the procedure control, and 6 bottles with the
toxicity control.
6. The concentration of the dissolved oxygen did not fall below 0.5 mg/l
throughout the test.
Biodegradability Test Procedure
All testing and reporting was conducted as per OECD 301D.
1. The contents of the large bottles were well mixed and any excess bubbles
were removed by gently tapping when finished stirring. The prepared
solutions were immediately transferred to their respective group of BOD
bottles by hose from the lower quarter (not the bottom) of the large flasks
until all the BOD bottles were completely filled.
The zero-time bottles were analyzed right away for dissolved oxygen. The
remaining bottles were stoppered, taking care to avoid trapping any air
bubbles inside, and those bottles stored at 20 degrees Celsius in an
incubator in the dark.
3. Each series of testing bottles was accompanied by a parallel series of
bottles with inoculated blank medium. These were withdrawn for analysis
at the same time intervals as the other bottles being tested. They were
checked weekly over the 28-day time period of the test.
Reference substance:
acetic acid, sodium salt
Parameter:
% degradation (DOC removal)
Value:
-3
Sampling time:
7 d
Parameter:
% degradation (DOC removal)
Value:
-2.8
Sampling time:
14 d
Parameter:
% degradation (DOC removal)
Value:
-2.5
Sampling time:
21 d
Parameter:
% degradation (DOC removal)
Value:
-1.9
Sampling time:
28 d
Details on results:
Validity of the Test
Oxygen depletion in the inoculum blank reached 1.07 mg dissolved oxygen/l at the end of 28 days. This did not exceed the method-specified limit of 1.5 mg dissolved oxygen/l.
The residual concentration of oxygen in the test bottles did not fall below 0.5 mg/l at any time. The difference of extremes of replicate values of the removal of the test chemical at the plateau was 2.01%. This difference did not exceed the method-specified limit of 20%. The removal of the reference compound on day 7 reached 64.09%, exceeding the method-specified minimum removal value of 60% of ThOD.
Results with reference substance:
The removal of the reference compound on day 7 reached 64.09%, exceeding the method-specified minimum removal value of 60% of ThOD.
Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
Results of biodegradability closed bottle test following the OECD 301D guidelines determined taht benzylated polyamine is not readily biodegrade over the course of the 28-day test, nor it is inhibitory to biodegradation of a reference compound.
Executive summary:

Results of biodegradability closed bottle test following the OECD 301D guidelines determined taht benzylated polyamine is not readily biodegrade over the course of the 28-day test, nor it is inhibitory to biodegradation of a reference compound.

Description of key information

Results of biodegradability closed bottle test following the OECD 301D guidelines determined that benzylated polyamine is not readily biodegrade over the course of the 28-day test, nor it is inhibitory to biodegradation of a reference compound.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed
Type of water:
freshwater

Additional information