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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Remarks:
Biodegration in water: sewage treatment simulation test
Type of information:
experimental study
Adequacy of study:
key study
Study period:
11/01/2012 - 08/03/2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP, Guideline study
Qualifier:
according to guideline
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
no
GLP compliance:
yes
Specific details on test material used for the study:
Radiolabelling: no
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
Aerobic activated sludge, micro organisms from a domestic waste water treatment plant was supplied by the sewage plant Rossdorf, Germany.
Duration of test (contact time):
28 d
Initial conc.:
102 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Reference substance:
other: Sodium benzoate
Remarks:
as procedure control
Test performance:
The test item dinotefuran technical contains nitrogen, therefore the evaluation of biodegradation has to be based ThODNH4 and ThODNO3. The criterion for ready biodegradability under the conditions of a manometric respirometry test is the 10-day window, describing the period between reaching at least 10% degradation and 60% degradation. This period should not exceed 10 days.
The mean biodegradation after 28 days of dinotefuran technical was 0% (ThODNH4) and (ThODNO3); the 10 day window criterion was not passed.
Therefore, dinotefuran technical is considered not to be readily biodegradable.
The reference item sodium benzoate was sufficiently degraded to 85% after 14 days and after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used.
In the toxicity control containing both, the test item and the reference item sodium benzoate, 52% (ThODNH4) and 35% (ThODNO3) biodegradation was noted within 14 days and 50% (ThODNH4) and 34% (ThODNO3) biodegradation after 28 days of incubation. Thus, the test item can be assumed to be not inhibitory to the aerobic activated sludge micro-organisms.
Identity of transformation product: No. Evaporation of parent compound, volatile metabolites, and resiudes were not measured.
Key result
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d
Details on results:
The test item dinotefuran technical contains nitrogen, therefore the evaluation of biodegradation has to be based ThODNH4 and ThODNO3. The criterion for ready biodegradability under the conditions of a manometric respirometry test is the 10-day window, describing the period between reaching at least 10% degradation and 60% degradation. This period should not exceed 10 days.

The mean biodegradation after 28 days of dinotefuran technical was 0% (ThODNH4) and (ThODNO3); the 10 day window criterion was not passed.
Therefore, dinotefuran technical is considered not to be readily biodegradable.
Results with reference substance
The reference item sodium benzoate was sufficiently degraded to 85% after 14 days and after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used.

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
The degradation rate of dinotefuran technical did not reach 60% within the 10-day window and after 28 days of incubation.
Therefore, dinotefuran technical is considered not to be readily biodegradable.
The percentage biodegradation of the reference item confirms the suitability of the used aerobic activated sludge inoculum.
According to the validity criteria of OECD test guideline 301, the test item can be assumed to be not inhibitory on the aerobic activated sludge micro organisms because degradation was > 25% within 14 days.

Description of key information

Dinotefuran is considered not to be readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed
Type of water:
other: activated sludge

Additional information