Interactive effects of temperature and UV radiation on antibiotic uptake and degradation in a floating (Salvinia molesta) and a submerged/emergent (Myriophyllum aquaticum) macrophyte.

Pharmaceutical contaminants increasingly affect aquatic environments; however, the influence of environmental stressors on macrophyte-mediated antibiotic removal remains poorly understood. This study examined how temperature (15-29°C), UV radiation (UV-A and UV-B), and antibiotic exposure (500 ng/L azithromycin, 400 ng/L amoxicillin, 400 ng/L ciprofloxacin, and 900 ng/L sulfamethoxazole) interact to influence the phytoremediation capacity of Salvinia molesta (floating) and Myriophyllum aquaticum (submerged/emergent). Antibiotic uptake, metabolic transformation, and physiological response were assessed under controlled conditions. Results revealed that S. molesta retained higher antibiotic concentrations, whereas M. aquaticum exhibited enhanced metabolic degradation, particularly under UV exposure. Temperature strongly influenced phytoremediation efficiency, with S. molesta performing optimally at 29°C, whereas M. aquaticum maintained stable performance across temperatures. UV exposure differentially affected phytoremediation and enhanced degradation in M. aquaticum but promoted antibiotic retention in S. molesta due to shading effects that limited UV-driven degradation in the water column. This study highlights the importance of plant morphotypes in contaminant fate, as floating species modulate UV penetration whereas submerged species directly facilitate degradation. These findings provide a novel framework for optimizing phytoremediation strategies across diverse aquatic environments, suggesting that mixed-species systems can enhance contaminant removal by integrating complementary remediation functions.