Registration Dossier

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018

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

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption

Results and discussion

% Degradation
Key result
Parameter:
% degradation (O2 consumption)
Value:
95.7
Sampling time:
28 d

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
Percentage of biodegradation at 28 days : 95.7 %
Conclusion : Readily biodegradable
Executive summary:

The objective of this study was to assess the aerobic ready biodegradability of test item by measurement of manometric respirometry over a 28-day period according to the OECD 301F guideline (July 1992).

The test item, at approximately 100 mg/L, as the sole source of carbon and energy, was incubated in a buffer-mineral salts medium which was inoculated with a mixed population of micro-organisms. The consumption of oxygen was determined from the change in pressure in the apparatus. Evolved carbon dioxide was absorbed in a solution of sodium hydroxide. The amount of oxygen taken up by the microbial population during biodegradation of the test substance (corrected for uptake by blank inoculum, run in parallel) was expressed as a percentage of ThODNH3.

As the test item is poorly soluble in test conditions and volatile, the test solutions were prepared by direct addition of the test item on the silica gel.

The study is valid since:

Based on a biodegradation rate higher than 60% in 14 days (experimental value: 78.9 and 69.1 % in 6 days) in the reference control, the test was carried out under good conditions.

At the end of the test, measurements of Biological Oxygen Demand (BOD) in two replicates of the test item solution did not show a difference of more than 20% (experimental value: 8.3 %).

The oxygen uptake of the control was not greater than 60 mg/l in 28 days (experimental value: 33.1 and 27.0 mg O2/L).

Based on a biodegradation rate higher than 25% in 14 days (experimental value: 97.4 % in 13 days) in the toxicity control, the test item was not toxic to micro-organisms.

Results are the following:

Percentage of biodegradation at 28 days : 95.7 %

Conclusion : Readily biodegradable