title: Macrophytes may not contribute significantly to removal of nutrients, pharmaceuticals, and antibiotic resistance in model surface constructed wetlands.
abstract: Outdoor shallow wetland mesocosms, designed to simulate surface constructed wetlands to improve lagoon wastewater treatment, were used to assess the role of macrophytes in the dissipation of wastewater nutrients, selected pharmaceuticals, and antibiotic resistance genes (ARGs). Specifically, mesocosms were established with or without populations of Typha spp. (cattails), Myriophyllum sibiricum (northern water milfoil), and Utricularia vulgaris (bladderwort). Following macrophyte establishment, mesocosms were seeded with ARG-bearing organisms from a local wastewater lagoon, and treated with a single pulse of artificial municipal wastewater with or without carbamazepine, clofibric acid, fluoxetine, and naproxen (each at 7.6μg/L), as well as sulfamethoxazole and sulfapyridine (each at 150μg/L). Rates of pharmaceutical dissipation over 28d ranged from 0.073 to 3.0d(-1), corresponding to half-lives of 0.23 to 9.4d. Based on calculated rate constants, observed dissipation rates were consistent with photodegradation driving clofibric acid, naproxen, sulfamethoxazole, and sulfapyridine removal, and with sorption also contributing to carbamazepine and fluoxetine loss. Of the seven gene determinants assayed, only two genes for both beta-lactam resistance (blaCTX and blaTEM) and sulfonamide resistance (sulI and sulII) were found in sufficient quantity for monitoring. Genes disappeared relatively rapidly from the water column, with half-lives ranging from 2.1 to 99d. In contrast, detected gene levels did not change in the sediment, with the exception of sulI, which increased after 28d in pharmaceutical-treated systems. These shallow wetland mesocosms were able to dissipate wastewater contaminants rapidly. However, no significant enhancement in removal of nutrients or pharmaceuticals was observed in mesocosms with extensive aquatic plant communities. This was likely due to three factors: first, use of naïve systems with an unchallenged capacity for nutrient assimilation and contaminant removal; second, nutrient sequestration by ubiquitous filamentous algae; and third, dominance of photolytic processes in the removal of pharmaceuticals, which overshadowed putative plant-related processes.
authors.affiliation: Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
authors.forename: Pascal
authors.initials: P
authors.lastname: Cardinal
authors.affiliation: Richardson College for the Environment, Department of Environmental Studies and Sciences, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada; Richardson College for the Environment, Department of Chemistry, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada.
authors.forename: Julie C
authors.initials: JC
authors.lastname: Anderson
authors.affiliation: Richardson College for the Environment, Department of Environmental Studies and Sciences, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada; Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; Richardson College for the Environment, Department of Chemistry, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada.
authors.forename: Jules C
authors.initials: JC
authors.lastname: Carlson
authors.affiliation: Richardson College for the Environment, Department of Environmental Studies and Sciences, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada; Richardson College for the Environment, Department of Chemistry, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada.
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Low
authors.affiliation: Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; Richardson College for the Environment, Department of Environmental Studies and Sciences, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada; Richardson College for the Environment, Department of Chemistry, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada.
authors.forename: Jonathan K
authors.initials: JK
authors.lastname: Challis
authors.affiliation: Richardson College for the Environment, Department of Environmental Studies and Sciences, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada; Richardson College for the Environment, Department of Chemistry, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Beattie
authors.affiliation: Richardson College for the Environment, Department of Environmental Studies and Sciences, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada; Richardson College for the Environment, Department of Chemistry, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada.
authors.forename: Caitlin N
authors.initials: CN
authors.lastname: Bartel
authors.affiliation: Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
authors.forename: Ashley D
authors.initials: AD
authors.lastname: Elliott
authors.affiliation: Richardson College for the Environment, Department of Environmental Studies and Sciences, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada; Department of Environmental Engineering, Costa Rica Institute of Technology, Cartago 30101, Costa Rica; Richardson College for the Environment, Department of Chemistry, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada.
authors.forename: Oscar F
authors.initials: OF
authors.lastname: Montero
authors.affiliation: Richardson College for the Environment, Department of Environmental Studies and Sciences, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada; Richardson College for the Environment, Department of Chemistry, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada.
authors.forename: Sheetal
authors.initials: S
authors.lastname: Lokesh
authors.affiliation: Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
authors.forename: Alex
authors.initials: A
authors.lastname: Favreau
authors.affiliation: Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
authors.forename: Tatiana A
authors.initials: TA
authors.lastname: Kozlova
authors.affiliation: Department of Civil & Environmental Engineering, University of Strathclyde, Glasgow, Scotland G1 1XJ, United Kingdom.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Knapp
authors.affiliation: Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Hanson
authors.affiliation: Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; Richardson College for the Environment, Department of Environmental Studies and Sciences, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada; Richardson College for the Environment, Department of Chemistry, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada. Electronic address: wong.charles.shiu@alum.mit.edu.
authors.forename: Charles S
authors.initials: CS
authors.lastname: Wong
mesh_terms: D001673:Biodegradation, Environmental; D002220:Carbamazepine / Q000032:analysis; D002995:Clofibric Acid / Q000032:analysis; D004352:Drug Resistance, Microbial / Q000235:genetics; D008956:Models, Chemical; D010944:Plants; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data*; D053833:Wetlands
chemical_list: D002220:Carbamazepine; D002995:Clofibric Acid; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Antibiotic resistance genes; Micropollutants; Pharmaceuticals; Surface flow constructed wetlands; Wastewater treatment