Registration Dossier

Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Primary biodegradation (89%) of an analogous substance occurs within 7 days in aerobic river water/sediment mixtures.  Mineralization to 14CO2 reached 5 and 15% of theoretical yield after 83 and 181 days, respectively.  

Key value for chemical safety assessment

Additional information

The primary biodegradation and mineralization of a 14C-radiolabeled C16 mono-alkyl/di-sulfonatated diphenyl oxide substance (DOWFAX 8390) was evaluated in freshwater river water/sediment mixtures under both aerobic and anaerobic conditions. This substance is structurally similar to the Dowfax 2A1 substance, with the alkyl group occurring as a branched C12 chain. The sulfonated diphenyl oxide structure is common to both substances, and radiolabeling was specific to the diphenyl oxide rings. Therefore, mineralization of the tested substance to 14CO2 demonstrated in this study is expected to represent the same rate/extent of degradation for the Dowfax 2A1 substance in surface water/sediments. Although degradation half-lives were not derived as part of these studies, it can be concluded based on the extent of 14CO2 yield at selected time points are indicative of ultimate degradation half-life of > 60 days in freshwater and > 180 days in freshwater sediments. However, these results indicate that the substances are ultimately biodegradable, and will not persist indefinitely in the aquatic environment.