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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from May 03 to May 05, 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Qualifier:
according to
Guideline:
EPA OPPTS 835.3110 (Ready Biodegradability)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid: viscous
Specific details on test material used for the study:
Test item identification: YELLOW 2747
Batch number: 78-242-15
manufacturing date: February 01, 2017 (in accordance to SOP G 04)
Expiry date : February 01, 2018 (in accordance to SOP G 04)
Chemical name: 1H-Benz[de]isoquinoline-1,3(2H)-dione,6-amino-,N,N’-bis[mixed 2-ethylhexyl and 3-[(2-ethylhexyl)oxy]
propyl] derivs
C.A.S. number: 1971906-58-7
The test item was stored at room temperature in the dark

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
The study was performed using aerobic activated sludge from BRIANZACQUE civil wastewater treatment plant. The sludge was collected on April 28, 2017. A homogenized aliquot of the wet sludge was centrifuged, the supernatant was removed while the solid phase was weighed, dried and the ratio of wet to dry weight was calculated to be equal to 6.13 %.
Based on this ratio, calculated amounts of wet sludge was centrifuged, the supernatant was removed and the solid phase was suspended in the test medium to get a concentration equivalent to 3 g dry material per litre.
The prepared sludge inoculum was pre-conditioned to the experimental conditions by aerating it in the dark. The concentrated suspension was used as inoculum to give a final concentration of 15 mg dry material per litre into test flasks.
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
74 mg/L
Based on:
COD
Details on study design:
Since the test item is not totally soluble in test medium, the test item was directly weighed into the test flasks to obtain the final concentrations of 50 mg/L of test item. The test flasks were made up to a final volume of 250 mL or 150 mL (based on setting scale) with test medium (see Table 1).

Moreover, stock solutions (10 g/L) of reference item Sodium Benzoate and sterilizing agent HgCl2 were prepared and an appropriate aliquot of the stock solution was added to the test medium (final volume: 250 mL or 150 mL ) in the test flasks to obtain a final concentration of 100 mg/L.
Activated sludge was added to each flask (with the exception of the abiotic control) before incubation.
Finally, the test flasks, containing stir bars covered with teflon, were kept under continuous stirring by the means of a magnetic stirrer for the 28-days test period.

Test environment: thermostat.
Monitoring of test medium pH: at the start and at the end of the test, in all test item flasks.
Test temperature: 21.6– 22.3 °C.
pH of test medium: 7.23 – 7.59 at the test start.
7.10 – 7.93 at the test end.


Results and discussion

% Degradation
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d
Details on results:
The biological results were referred to nominal concentration of test item
Nitrate formation: 0.098 mg total oxygen equivalent for nitrate formation.
Nitrite formation: none.

No significant degradation was observed in the abiotic control.

The test item showed no inhibitory effects on the microorganism activity at the tested concentration, as demonstrated by the biodegradation percentage in the toxicity control exceeding the 25% pass level after four days of exposure (25.0%).

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test item was found to be not ready and completely biodegradable under the conditions applied in a manometric respirometry test.
Biodegradation at the end of the test period (28 days of exposure) was equal to 0.0 % (mean percentage values between two test item replicates).
This value of biodegradation at the end of the test was corrected with nitrification contribution.