title: Toxicity of chlortetracycline and its metal complexes to model microorganisms in wastewater sludge.
abstract: Complexation of antibiotics with metals is a well-known phenomenon. Wastewater treatment plants contain metals and antibiotics, thus it is essential to know the effect of these complexes on toxicity towards microorganisms, typically present in secondary treatment processes. In this study, stability constants and toxicity of chlortetracycline (CTC) and metal (Ca, Mg, Cu and Cr) complexes were investigated. The calculated stability constants of CTC-metal complexes followed the order: Mg-CTC>Ca-CTC>Cu-CTC>Cr-CTC. Gram positive Bacillus thuringiensis (Bt) and Gram negative Enterobacter aerogenes (Ea) bacteria were used as model microorganisms to evaluate the toxicity of CTC and its metal complexes. CTC-metal complexes were more toxic than the CTC itself for Bt whereas for Ea, CTC and its metal complexes showed similar toxicity. In contrast, CTC spiked wastewater sludge (WWS) did not show any toxic effect compared to synthetic sewage. This study provides evidence that CTC and its metal complexes are toxic to bacteria when they are biologically available. As for WWS, CTC was adsorbed to solid part and was not biologically available to show measurable toxic effects.
authors.affiliation: INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec, G1K 9A9, Canada.
authors.forename: Rama
authors.initials: R
authors.lastname: Pulicharla
authors.affiliation: INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec, G1K 9A9, Canada.
authors.forename: Ratul Kumar
authors.initials: RK
authors.lastname: Das
authors.affiliation: INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec, G1K 9A9, Canada. Electronic address: satinder.brar@ete.inrs.ca.
authors.forename: Satinder Kaur
authors.initials: SK
authors.lastname: Brar
authors.affiliation: INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec, G1K 9A9, Canada.
authors.forename: Patrick
authors.initials: P
authors.lastname: Drogui
authors.affiliation: INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec, G1K 9A9, Canada.
authors.forename: Saurabh Jyoti
authors.initials: SJ
authors.lastname: Sarma
authors.affiliation: CO2 Solutions Inc., 2300, Rue Jean-Perrin, Québec, Québec G2C 1T9, Canada.
authors.forename: Mausam
authors.initials: M
authors.lastname: Verma
authors.affiliation: Department of Civil Engineering, University of Nebraska-Lincoln, N104 SEC PO Box 886105, Lincoln, NE 68588-6105, USA.
authors.forename: Rao Y
authors.initials: RY
authors.lastname: Surampalli
authors.affiliation: INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec, G1K 9A9, Canada.
authors.forename: Jose R
authors.initials: JR
authors.lastname: Valero
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D001419:Bacteria; D002751:Chlortetracycline / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D056831:Coordination Complexes / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D008670:Metals / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D008956:Models, Chemical; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D002751:Chlortetracycline; D056831:Coordination Complexes; D008670:Metals; D062065:Wastewater
keywords: Bacteria; Chlortetracycline; Metal complexation; Toxicity; Wastewater sludge