Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

The test item was determined to be not readily biodegradable but the results of the test can be used to support inherent biodegradability (OECD 301 F).

Additional information

Biodegradation

GUIDELINE

The objective of the study was to evaluate the test item for its ready biodegradability in an aerobic aqueous medium with microbial activity introduced by inoculation with activated sludge; Manometric Respirometry Test. Study procedures were conducted in compliance with OECD Guideline 301F, Section 3. Degradation and Accumulation. "Ready Biodegradability: Manometric Respirometry Test", (adopted July 17, 1992).

METHODS

The test item was a clear colourless liquid with a purity of 84.1%. The Theoretical Oxygen Demand with full nitrification (ThODNO3) of test item was calculated to be 2.62 mg O2/mg. The test item was tested in duplicate at a target concentration of 30.5 mg/L, corresponding to a ThODNO3 of 80 mg O2/L. The ThODNO3 was based on the results of elemental composition analysis and was confirmed by TOC analysis. The study consisted of six bottles: 2 inoculum blanks (no test item); 2 test bottles (test item); 1 procedure control (1-octanol) and; 1 toxicity control (test item plus 1-octanol).

 

The test item was added directly to the inoculated mineral medium. The test solutions were continuously stirred during the test to ensure optimal contact between the test item and test organisms. Test duration was 28 days. In order to transfer test item to the test vessels, the required amounts were pipetted directly into the test bottles containing medium with microbial organisms and mineral components.

RESULTS

The relative biodegradation values calculated from the measurements performed during the test period revealed 59 % and 47 % biodegradation of test item based on ThODNO3, for the duplicate bottles tested. Thus, the criterion for ready biodegradability (at least 60% biodegradation within a 10-day window) was not met. In the toxicity control, test item was found not to inhibit microbial activity. Since all criteria for acceptability of the test were met, this study was considered to be valid.

CONCLUSION

The test item was not readily biodegradable under the conditions of the Manometric Respirometry Test presently performed. However, since the results of the present test indicate that the pass level criterion was almost fulfilled the results can be used to support inherent biodegradability.