The in vivo and vitro degradation of sulfonamides in wetland plants reducing phytotoxicity and environmental pollution.

Abstract

Aquatic plants can be used for in situ remediation of water-borne pharmaceutical compounds; however, such information and that of the potential risks of metabolites released into the environment are limited. This study determined the capacity of Canna indica and Acorus calamus used in the remediation of water-borne sulfonamides (SA). The tolerance, removal, accumulation, and biotransformation of various water-borne SAs were investigated in vivo by exposing plants to SA solutions (50µg/L and 500µg/L). After 28days, C. indica removed more SAs (89.3-97.8%) than A. calamus (12.8-84.6%) and non-planted systems (8.0-69.3%). The SA removal results, except from the A. calamus system with 500µg/L SA, fit the first-order kinetics model. The estimated half-lives of all SAs were 3-40h and 2-60h in the C. indica and A. calamus systems, respectively. In vivo biotransformation and rhizosphere degradation were the major phyto-removal mechanisms, constituting 24.9-81.1% and 0.0-37.1% of all SAs in the C. indica and A. calamus systems, respectively. SA acetyl metabolites were detected only in plant tissues supporting evidence for plant metabolic processes without risk into the environment. SA metabolism including oxidation, methylation, and conjugation via acetylation was potentially beneficial to accumulation and tolerate stress of antibiotic. Canna indica was more suitable for cleaning SA. Our findings better clarify the potential and low risks of phytoremediation in antibiotic-contaminated waters.