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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
28 d
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019
Report Date:
2019

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Test material form:
solid: particulate/powder

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
Aerobic biodegradation of the test item was determined by measuring oxygen consumption in an inoculum containing aerobic mixed bacterial culture originated from a municipal wastewater treatment plant and maintained at laboratory conditions. The bacterial culture was not adapted to the test item.
Type of inoculum: aerobic mixed bacterial culture
Source: Municipal wastewater treatment plant, Esztergom-Kertváros
Date of arriving: 03 July 2017
Duration of test (contact time):
28 d
Details on study design:
The amount of oxygen consumed by the microorganisms when metabolising the test item is called Biochemical Oxygen Demand (BOD). The BOD of test item is determined by the manometric respiratory - OxiTop® system. The principle of the determination of BOD by OxiTop® - system is based on the measurement of the consumption of oxygen by a pressure sensor in the top of the tightly closed test vessels.
Test vessels with the test item solution and mixed bacterial culture, so called inoculum, are under continuous stirring in an incubator at 21 ± 1 °C for 28 days. The carbon dioxide which is evolved during the biodegradation is absorbed by sodium hydroxide granulates. The reduced amount of oxygen causes definite pressure changes in the test vessels which are measured by the apparatus. The amount of oxygen taken up by microorganisms during biodegradation of the test item is expressed as a percentage of theoretical oxygen demand (ThOD).
The percentage of biodegradability of the test item is calculated on the base of quotient of 28-day biochemical oxygen demand (BOD28) and theoretical oxygen demand. The pass level for the biodegradability is 60% of ThOD for Manometric Respirometry method. The pass value has to be reached in 10 days (10-d) window within the 28-day period of the test. The 10-d window begins when the degree of biodegradation has reached 10% ThOD and must end before day 28 of the test. Biodegradability classification of the test item is made according to OECD 301 guideline, which says that chemicals which reach the pass level up to 28-d period are deemed to be readily biodegradable.
Reference substance
Reference substance:
acetic acid, sodium salt

Results and discussion

Test performance:
Aerobic biodegradation of the test item was determined by measuring oxygen consumption in an inoculum containing aerobic mixed bacterial culture originated from a municipal wastewater treatment plant and maintained at laboratory conditions. The bacterial culture was not adapted to the test item. The Biochemical Oxygen Demand for 28 days (BOD28) of test item were determined by the manometric respiratory - OxiTop® system. Blank controls, a positive control (reference item), a toxic control and an abiotic control treatment were also included in the study. The test duration was 28 days. Sodium acetate was used as reference item. The measured BOD values for test item, positive and toxicity controls were corrected with the results of blank controls. Next table below summarizes the biodegradation data (BOD28/ThOD, %) measured at the end of the test.
The percentage of biodegradability of the test item is calculated on the base of quotient of 28-day biochemical oxygen demand (BOD28) and theoretical oxygen demand. The pass level for the biodegradability is 60% of ThOD for Manometric Respirometry method. The pass value has to be reached in 10 days (10-d) window within the 28-day period of the test. The 10-d window begins when the degree of biodegradation has reached 10% ThOD and must end before day 28 of the test.
% Degradation
Key result
Parameter:
% degradation (O2 consumption)
Value:
4
Sampling time:
28 d
Remarks on result:
other:
Remarks:
mean of two replicates

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
According to OECD guideline the test item should be classified as readily biodegradable if the percentage biodegradation reaches 60% of theoretical oxygen demand within 28 day period in a 10-day window.
Based on ready biodegradability testing results the Acetoxy-AD-enolether is not readily biodegradable.