Removal of veterinary antibiotics in constructed wetland microcosms – Response of bacterial communities

• Published in: Ecotoxicology and environmental safety Vol. 169; pp. 894 - 901
• Main Authors: Santos, Filipa, Almeida, Cristina Marisa Ribeiro de, Ribeiro, Iolanda, Ferreira, Ana Catarina, Mucha, Ana Paula
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.03.2019
• Subjects: Ceftiofur; Enrofloxacin; Livestock effluent; Microbial structure; Mixture of antibiotics; Microbial structure; Mixture of antibiotics; Livestock effluent; Ceftiofur; Enrofloxacin
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2018.11.078

This study aimed to evaluate the response of bacteria, in terms of microbial community structure, from constructed wetland (CW) microcosms exposed to two veterinary antibiotics, enrofloxacin (ENR) and ceftiofur (CEF), alone or in a mixture, identifying which bacterial groups were dominant in CWs substrate during livestock wastewater treatment. Wastewater, not-doped or doped with ENR and/or CEF (100 µg/L each), was treated during 18 one-week cycles. Systems showed removal percentages > 85% for the added antibiotics, showing also high removal percentages for nutrients and organic matter and confirming CWs systems were working properly. However, both time of exposure and presence of antibiotics influenced significantly CWs substrate bacterial community structure. Pyrosequencing results showed bacterial communities were dominated by phyla Proteobacteria (38–48%), Firmicutes (20–27%), Bacteroidetes (12–15%) and Actinobacteria (4–9%), and that their relative abundance was clearly affected by the presence of the antibiotics. Results suggest the applicability of CWs for the removal of veterinary antibiotics from livestock wastewaters and provide new knowledge about the bacteria within the system, which can potentially be involved in removal processes. This information could in the future be used to improve CWs removal rates of pharmaceuticals from livestock wastewaters. •Time of exposure influenced significantly substrate bacterial community structure.•Relative abundance of bacterial communities phyla clearly affected by antibiotics presence.•Despite this, constructed wetlands showed antibiotics removals higher than 90%.