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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:
2020
Report Date:
2020

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
Type:
Constituent
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
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
Preparation of inoculum test culture: Before the test 300 ml stock culture was filtered through a filter with 0.2 mm pore size to remove the bigger insoluble particles and then the dry substance content of the filtrate was determined. The measured value was 6.41 g/L. For preparing the inoculum culture 169 ml mineral medium was added to 31 ml filtered stock culture. The calculated dry mass of inoculum culture was 1 g/L.
Preparation of test vessels:
Following test vessels were prepared and analysed for the study:
- Test item (in two replicates)
- Blank control (in two replicates)
- Reference solution (positive control)
- Reference and test item solution (toxicity control)
- Sterilized solution of test item (abiotic control)
Rubber sleeves with sodium-hydroxide pellets were mounted into the vessels. The test vessels were tightly closed with measuring heads and placed into thermostat. The temperature during the test was adjusted to 21 ± 1 °C. The vessels were kept in complete darkness and they were stirred continuously.
The vessels were kept in thermostat for 28 days. On the OxiTop® controller the actual parameters (test duration, final volume, number of
test vessels) were adjusted.
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.
% Degradation
Parameter:
% degradation (O2 consumption)
Value:
46
Remarks on result:
other: mean of two replicates

BOD5 / COD results

Results with reference substance:
Reference solution (positive control): 66%

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 15α-hydroxy-androstenedione is not readily biodegradable.