Biodegradation and Photodegradation of Selected Antimicrobial/ Antifungal Agents in the Aquatic Environment and Their Sorption onto Sediments

• Published in: Journal of Environmental Chemistry Vol. 22; no. 3; pp. 113 - 119
• Main Authors: TAMURA, Ikumi, YAMAMOTO, Hiroshi
• Format: Journal Article
• Language: Japanese
• Published: Japan Society for Environmental Chemistry 2012
• Subjects: antimicrobials; biodegradation; photodegradation; sorption
• ISSN: 0917-2408; 1882-5818
• DOI: 10.5985/jec.22.113

Triclosan, triclocarban, and other antimicrobial and antifungal agents have recently become a significant concern for public due to their potentially high ecological risk for aquatic organisms. In the present study, laboratory riverwater biodegradation, sunlight photodegradation and sorption experiments using river sediments were conducted for four selected antimicrobials and antifungal agents of concern, triclosan, triclocarban, and their alternatives, phenoxyethanol, and 4-isopropyl-3-methylphenol, to estimate their fate and transport in the aquatic environment. As results, we found relatively fast removal of triclosan by sunlight while the other three compounds were found to be recalcitrant against sunlight emission. As for the degradation in the river water, relatively fast degradation of phenoxyethanol and moderate degradation of triclocarban was observed while triclosan and 4-isopropyl-3-methylphenol are somewhat resistant against microbes. The sorption coefficients of triclosan and triclocarban were relatively high and comparable to a four-ring polycyclic hydrocarbon, pyrene, and they are possible to accumulate in the sediment while phenoxyethanol and 4-isopropyl-3-methylphenol remain in the aqueous phase. These results overall suggests the relatively high accumulation of triclosan and triclocarban in the sediment due to their high hydrophobicity and their effects on benthic organisms could be the significant concern as well as those on aquatic organisms. In contrast, phenoxyethanol and 4-isopropyl-3-methylphenol tend to remain in the aqueous phase, which agrees to the relatively high detected concentrations of these compounds in the urban streams with unsewered watershed area.