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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
Study period:
2021-01-07 - 2021-04-29
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
Aeration tank of a wastewater plant treating predominantly domestic sewage (Wupper area water authority, WWTP Odenthal).
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
A suspension of 100 mg/L test item in a mineral medium, equalling to 236 mg 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.
Reference substance:
benzoic acid, sodium salt
Parameter:
% degradation (O2 consumption)
Value:
12
Sampling time:
21 d
Remarks on result:
other: Standard deviation not given.
Parameter:
% degradation (O2 consumption)
Value:
11
Sampling time:
14 d
Remarks on result:
other: Standard deviation not given.
Parameter:
% degradation (O2 consumption)
Value:
9
Sampling time:
7 d
Remarks on result:
other: Standard deviation not given.
Parameter:
% degradation (O2 consumption)
Value:
13
Sampling time:
28 d
Remarks on result:
other: Standard deviation not given.
Details on results:
The biodegradation of Reaction products of m-cresol and propene, high boiling alkylphenol isomers was 13 % (COD) after 28 days. The test item failed the pass level requested in test method OECD 301 F which is a biodegradation ≥ 70 % DOC or ≥ 60 % COD.
Results with reference substance:
The reference compound sodium benzoate showed 88 % degradation after 14 days.
Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
The biodegradation of Reaction products of m-cresol and propene, high boiling alkylphenol isomers was 13 % (COD) after 28 days. The test item failed the pass level requested in test method OECD 301 F which is a biodegradation ≥ 70 % DOC or ≥ 60 % COD.

The test item is, therefore, considered to be not readily biodegradable.
Executive summary:

The study was conducted in accordance with the Council Regulation (EC) No 440/2008, Method C.4-D “Manometric Respirometry Test“(2008). This test method is in all essential parts identical with OECD Guideline 301 F (adopted July 1992).
A suspension of 'reaction products of m-cresol and propene, high boiling alkylphenol isomers' 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.


The 28-day degradation was 13 % while a biodegradation of 88 % was observed for the positive control (with reference substance sodium benzoate). In conclusion the substance is not readily biodegradable under test conditions.
The degradation rate of the test item was set in relation to its experimentally determined COD. As the COD implicitly covers the oxygen demand for the nitrification process, there was no need to take additional correction measures into account.

Description of key information

The study was conducted in accordance with the Council Regulation (EC) No 440/2008, Method C.4-D “Manometric Respirometry Test“(2008). This test method is in all essential parts identical with OECD Guideline 301 F (adopted July 1992).
A suspension of 'reaction products of m-cresol and propene, high boiling alkylphenol isomers' 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.


The 28-day degradation was 13 % while a biodegradation of 88 % was observed for the positive control (with reference substance sodium benzoate). In conclusion the substance is not readily biodegradable under test conditions.
The degradation rate of the test item was set in relation to its experimentally determined COD. As the COD implicitly covers the oxygen demand for the nitrification process, there was no need to take additional correction measures into account.

Key value for chemical safety assessment

Biodegradation in water:
not biodegradable
Type of water:
freshwater

Additional information