Interaction of veterinary antibiotic tetracyclines and copper on their fates in water and water hyacinth (Eichhornia crassipes)

Water hyacinth (Eichhornia crassipes) may provide an alternative solution for the removal of co-contamination between antibiotics and heavy metals from livestock and poultry wastewater. A hydroponic experiment was conducted to investigate interaction of tetracyclines (TCs) and copper (Cu) on growth of E. crassipes, removal of TCs and Cu by plants and their fates in solution. After 20 days, plant growth, concentrations and accumulation of Cu and TCs in plants, removal by plants, and dissipation in solution were significantly influenced by interaction of Cu and TCs. Influence of only Cu or TCs on plant growth was not significant, except for TCs at 15 mg L−1 which produced a negative effect on plant biomass. The presence of low-Cu and high-TCs acted synergistically to promote the negative effect of TCs on plant biomass, but increasing Cu concentration partially alleviated the adverse effect. Co-contamination of low-concentration Cu and TCs could exert antagonistic effects on the removal and accumulation of Cu and TCs by plants; in contrast, synergistic effects were found for the combination of high-concentration Cu and TCs. The Cu/TCs in solution could effectively be removed using E. crassipes. Plants significantly enhanced dissipation of TCs in solution. Hence, interaction of TCs and Cu should be taken into consideration when judging (1) an ecotoxicological potential of TCs and Cu residues in aquatic environments, and (2) removal efficiency of TCs and Cu in phytoremediation.