Phytoextraction of ciprofloxacin and sulfamethoxaxole by cattail and switchgrass

Abstract

Cattail (Typha latifolia L.) and switchgrass (Panicum virgatum L.) can effectively remove inorganic contaminants from soils and biosolids, but their role in the attenuation of organic contaminants, such as antimicrobials, is currently poorly understood. Uptake by plants is one of several mechanisms by which plant-assisted attenuation of antimicrobials can be achieved. The objectives of this growth room study were to evaluate the plant uptake of ciprofloxacin (CIP) and sulfamethoxazole (SMX) and examine their partitioning between plant roots and aboveground biomass (AGB). Plant uptake of the two ¹⁴C labeled antimicrobials was studied at two environmentally relevant concentrations (5 and 10 μg L^-1). Plants were destructively sampled every 3-4 d during the 21-d growth period. Accumulation of CIP and SMX in both plant species was greater in the roots than in the AGB. The percentage uptake values of the two antimicrobials were significantly greater for cattail (34% for CIP, 20% for SMX) than for switchgrass (10% for both CIP and SMX). Translocation factors of the two antimicrobials were <1 for both plants, indicating slow movement of the antimicrobials from the roots to the shoots. For cattail roots, the BCF for CIP (1.58 L g^-1) was significantly greater than that for SMX (0.8 L g^-1). By comparison, BCFs for switchgrass roots did not differ significantly between CIP (0.88 L g^-1) and SMX (1.13 L g^-1). These results indicate greater potential for cattail to phytoextract CIP and SMX and significantly contribute to the attenuation of these antimicrobials in systems designed for the phytoremediation of contaminated wastewater.

Keywords: Antimicrobials; Logistic models; Phytoremediation; Translocation factor.