Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

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:
2017-06-01 until 2016-10-06
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Version / remarks:
adopted July 1992
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
Version / remarks:
2008
Deviations:
no
GLP compliance:
yes
Remarks:
according to Annex I, German Chemical Law
Specific details on test material used for the study:
Date of receipt : 2014-01-15
Expiry date : 2017-09-17
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
Type : mixed population of aquatic microorganisms (activated sludge)
Origin : aeration tank of a wastewater plant treating predominantly domestic sewage (Wupper area water authority, WWTP Odenthal)
Date of collection : 2017-03-06
Concentration of inoculum : 30 mg/L suspended solids
Pre-treatment of the inoculum
− Before use, the inoculum was stored for two days at room temperature under continuous stirring with aeration.
− The sludge was washed twice by adding mineral medium and centrifuging for 10 min at 2000 rpm and 20 °C and decanting off the supernatant.
− An aliquot of the wet sludge was dried in order to determine the wet weight / dry weight ratio of the sludge and to prepare a stock suspension (activated sludge) of 3 g dw/L.
− The calculated amount of sludge, needed to achieve 300 mL of this stock suspension, was dissolved in mineral medium and then filled up to a defined end volume.
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Remarks:
consumption of oxygen (BOD) was determined by measuring the drop in pressure in the automated respirometer flasks
Details on study design:
This study was designed to assess the ready biodegradability of phosphorothioyltris(oxybenzene-4,1-diylcarbamoyloxyethane-2,1-diyl) trisprop-2-enoate.
A suspension of 100 mg/L test item in a mineral medium, equalling to 50-100 mg ThOD or COD/Litre as the nominal sole source of organic carbon, was stirred in a closed flask and inoculated at a constant temperature (22 ± 1 °C) for up to 28 days under aerobic conditions in the dark.

The endogenous activity of the inoculum was checked running parallel blanks with inoculum but without test item. A reference compound (sodium benzoate) was run in parallel to check the operation of the procedures.
A toxicity control (test item and reference compound mixed, one replicate) was run in parallel, to ensure that the chosen concentration of the test item was not inhibitory to microorganisms.
Degradation was followed by the determination of oxygen uptake and measurements were taken at frequent intervals to allow the identification of the beginning and end of biodegradation and the slope of the biodegradation curve.

Because of the nature of biodegradation and of the mixed bacterial populations used as inoculum, determinations of test item and inoculum blank were carried out in triplicate and of reference compound in duplicate.

The test item is an N-containing substance. Therefore, the concentration of nitrite and nitrate was determined at the start of the test. The oxygen consumed by nitrification was not determined after 28 days, because poor degradation of the test item was observed.

Exposure conditions
Test volume : 250 mL
Test apparatus : OxiTopControl System (WTW)
Mixing : 1 magnetic stirrer per test vessel
Incubation time : 28 days
Incubation temperature : 22 ± 1 °C
Reference substance:
benzoic acid, sodium salt
Parameter:
% degradation (O2 consumption)
Value:
1
Sampling time:
28 d
Details on results:
phosphorothioyltris(oxybenzene-4,1-diylcarbamoyloxyethane-2,1-diyl) trisprop-2-enoate showed:
1 % degradation after 7 days
0 % degradation after 14 days
0 % degradation after 21 days
1 % degradation after 28 days
Parameter:
ThOD
Value:
1.494 mg O2/g test mat.
Remarks on result:
other: Test concentration: 100 mg/L
Results with reference substance:
Degradation of reference compound:
Test concentration : 100 mg/L
Theoretical oxygen demand : 1.665 mg O2/mg
The reference compound reached the level of ≥ 60 percent for ready biodegradability within 14 days.

The oxygen consumed by nitrification was not determined at the end of the study, because poor degradation of the test item was observed and the correction for oxygen uptake by nitrification would not have an influence on the results.

Validity criteria fulfilled:
yes
Remarks:
The toxicity control exhibited degradation rates > 25 % within 14 days. At the end of the test, at the plateau, or the end of the 10-d window, biodegradation in parallels with test item did not differ by more than 20 percentage points.
Interpretation of results:
not readily biodegradable
Conclusions:
A study on degradation of phosphorothioyltris(oxybenzene-4,1-diylcarbamoyloxyethane-2,1-diyl) trisprop-2-enoate was performed according to OECD Guideline 301 F showing 1 % degradation after 28 days. Therefore, the test item is considered to be “Not Readily Biodegradable“.
Executive summary:

A study was performed to assess the ready biodegradability of phosphorothioyltris(oxybenzene-4,1-diylcarbamoyloxyethane-2,1-diyl) trisprop-2-enoate according to OECD Guideline 301 F. A suspension of the test item in a mineral medium was inoculated and incubated for 28 d under aerobic conditions. During this period, degradation was followed by continuous automated BOD determinations. Phosphorothioyltris(oxybenzene-4,1-diylcarbamoyloxyethane-2,1-diyl) trisprop-2-enoate showed a 1 % degradation after 28 days and is therefore considered to be “Not Readily Biodegradable“.

Description of key information

A study on degradation of phosphorothioyltris(oxybenzene-4,1-diylcarbamoyloxyethane-2,1-diyl) trisprop-2-enoate was performed according to OECD Guideline 301 F showing 1 % degradation after 28 days. Therefore, the test item is considered to be “Not Readily Biodegradable“.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information