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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:
2020
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)
Version / remarks:
OECD 301 F (July 1992)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Specific details on test material used for the study:
Active substance: 100%
Oxygen conditions:
anaerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
Activated sludge from the municipal wastewater treatment plant Breisgauer Bucht was used as inoculum with a concentration corresponding to 30 mg dry solids per litre. The treatment plant clarifies predominantly domestic wastewater and has a capacity of 600.000 inhabitant equivalents. Sampling date of activated sludge was 21 January 2020. The dry solids (d.s.) content of the activated sludge was 4.6 g/L. It was determined by weight measurements after drying at 105°C for about 4.5 hours (mean of triplicate measurements).
Duration of test (contact time):
28 d
Initial conc.:
60.1 mg/L
Based on:
ThOD
Key result
Parameter:
% degradation (TOC removal)
Value:
0
Sampling time:
28 d
Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
No degradation of the test item could be observed within the test duration. The mean degradation after 28 days was just below 0% (-0.1% ThODNO3 / ThODNH4, each mean of three replicates).
The test item did not reach the criteria for ready biodegradability (60% of ThOD within 28 days and within a 10-d window).
The degradation of the toxicity control after 14 days was >25%. The test item had no inhibitory effect on the inoculum according to the criterion of the guideline.
Executive summary:

No degradation of the test item could be observed within the test duration. The mean degradation after 28 days was just below 0% (-0.1% ThODNO3 / ThODNH4, each mean of three replicates).

The test item did not reach the criteria for ready biodegradability (60% of ThOD within 28 days and within a 10-d window).

The degradation of the toxicity control after 14 days was >25%. The test item had no inhibitory effect on the inoculum according to the criterion of the guideline.

Description of key information

No degradation of the test item could be observed within the test duration. The mean degradation after 28 days was just below 0% (-0.1% ThODNO3 / ThODNH4, each mean of three

replicates).

The test item did not reach the criteria for ready biodegradability (60% of ThOD within 28 days and within a 10-d window).

The degradation of the toxicity control after 14 days was >25%. The test item had no inhibitory effect on the inoculum according to the criterion of the guideline.

Key value for chemical safety assessment

Biodegradation in water:
not biodegradable
Type of water:
freshwater

Additional information