Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

The test substance was considered not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

A study was conducted to determine the ready biodegradability of the test substance according to OECD Guideline 301B and EU Method C.4 -C (CO2 evolution test), in compliance with GLP. Domestic activated sludge was exposed to the test substance at concentrations of 0 or 17.5 mg/L (i.e., corresponding to 12 mg TOC/L) for 28 days. A positive control (sodium acetate) and a toxicity control (test substance + sodium acetate) were included in the experiment followed by sampling at regular intervals to measure the CO2 evolution. The amount of CO2 produced was determined by titrating the remaining Ba(OH)2 with with standardised HCl. Each sample was measured in duplicates. The relative biodegradation values calculated from the measurements performed during the test period revealed 14% and 15% biodegradation of the test substance (based on ThCO2), 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, the test substance was found not to inhibit microbial activity. Since all criteria for acceptability of the test were met, this study was considered to be valid. Under the study conditions, the test substance was considered not readily biodegradable (Desmares-Koopmans, 2017).