Fate of famoxadone in the environment

Abstract

The fate of famoxadone [Famoxate®, 3-anilino-5-methyl-5-(4-phenoxyphenyl)-1,3-oxazolidine-2,4-dione] in the aquatic and soil environment was examined. It was found to be relatively stable at pH 5, but hydrolysed rapidly in pH 7 and 9 buffer solutions. Primary hydrolytic degradation reactions included the opening of the oxazolidinedione ring and the cleavage of the oxazolidinedione-aminophenyl linkage. The compound degraded rapidly in soil by both hydrolytic and microbial action. In addition to the generation of [ 14 C] carbon dioxide and unextractable bound residues, hydroxylation and hydrolysis reactions occurred to yield multiple degradation products. Nitration of famoxadone at the 2- or 4-phenylamino position was observed as a novel non-biological degradation reaction of famoxadone in soil. Degradation in aqueous solution (pH 5) and on soil surfaces was accelerated under simulated sunlight irradiation. Famoxadone exhibited negligible soil mobility potential, and its primary degradation products were also shown to dissipate rapidly in the environment.