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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

Administrative data

Endpoint:
biodegradation in water: sewage treatment simulation testing
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

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2012

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
other: Commission Regulation 440/2008/EC, Method C.4-D
Deviations:
no
Qualifier:
according to
Guideline:
other: OECD 301 F
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: solid
Details on test material:
Purity 99.4%
Batch No. K09A3559
Radiolabelling:
no

Study design

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 test substance concentration
Initial conc.:
102 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Reference substance
Reference substance:
other: Sodium benzoate as procedure control

Results and discussion

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.
% Degradation
% Degr.:
0
Parameter:
O2 consumption
Sampling time:
28 d
Transformation products:
not measured
Evaporation of parent compound:
not measured
Volatile metabolites:
not measured
Residues:
not measured
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.

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.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
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.