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Environmental fate & pathways

Biodegradation in soil

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Description of key information

Mineralization of a radiolabeled analogous substance to 14CO2 resulted in 50-67%, 17 - 75%, and 52%  of theoretical CO2 yield after 366 days in aerobic surface soils, freshwater sediments, and estuarine sediments, respectively.  

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Additional information

The primary biodegradation and mineralization of a 14C-radiolabeled C16 mono-alkyl/di-sulfonatated diphenyl oxide substance (DOWFAX 8390) was evaluated in aerobic surface soils, freshwater sediments, and an estuarine sediment over 266 days. 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 > 180 days in soils and sediments. However, these results indicate that the substances are ultimately biodegradable, and will not persist indefinitely in the terrestrial or aquatic environments.