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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #424080
Research Project: Managing Manure as a Soil Resource for Improved Biosecurity, Nutrient Availability, and Soil Sustainability

Location: Agroecosystem Management Research

Title: Isotopically tracing the impact of water contaminant “cocktails” on nitrogen pathways in constructed treatment wetlands

Author
item BYERS, EMILY - University Of Kentucky
item MESSER, TIFFANY - University Of Kentucky
item TOBIAS, CRAIG - University Of Kentucky
item Miller, Daniel
item BARTON, CHRISTOPHER - University Of Kentucky
item UNRINE, JASON - University Of Kentucky
item AGOURIDIS, CARMEN - University Of Kentucky

Submitted to: Water Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/23/2025
Publication Date: 7/24/2025
Citation: Byers, E.N., Messer, T.L., Tobias, C., Miller, D.N., Barton, C., Unrine, J., Agouridis, C. 2025. Isotopically tracing the impact of water contaminant “cocktails” on nitrogen pathways in constructed treatment wetlands. Water Research. 287. Article 124294. https://doi.org/10.1016/j.watres.2025.124294.
DOI: https://doi.org/10.1016/j.watres.2025.124294

Interpretive Summary: Wetland treatment systems effectively treat surface runoff, but the effects of contaminant mixtures on wetland performance is not well understood. An isotopic tracer method was used to assess how urban contaminants (imidacloprid, caffeine, and PFOS) and rural contaminants (atrazine, glyphosate, and sulfate) impact N removal pathways in two constructed wetland designs, floating treatment wetlands (FTW) and free-water surface wetlands (FWS). Contaminants mixtures reduced overall N removal with more N taken up in plants in treatments with contaminants compared to controls. After 10 days, 98% of the stable isotope was accounted for in the mesocosms without vegetation while a large fraction (23-86%) was unaccounted in the planted mesocosms, indicating gas diffusion from the plant biomass may be very important. Both wetland designs are viable treatment options for N removal but differences in management and maintenance plans are recommended due to the FTWs accumulated more N in their biomass. Furthermore, N processes in two constructed wetlands will be impacted based upon contaminants in the landscape (e.g., urban, rural).

Technical Abstract: Wetland treatment systems are used extensively to mitigate surface runoff, yet implications of common contaminant “cocktail” mixtures to wetland performance are relatively unexplored. A 15N isotopic tracer was used to assess the impact contaminants from urban (imidacloprid, caffeine, and PFOS) and rural (atrazine, glyphosate, and sulfate) environments have on nitrogen (N) pathways. Two constructed wetland designs, floating treatment wetlands (FTW) and free-water surface wetlands (FWS), were assessed using pulse flow enrichments along with planted and un-planted controls. Contaminant mixtures were observed to reduce N removal with increased N plant uptake in treatments with contaminants compared to planted controls. Furthermore, after 10 days, 98% of the 15N was accounted for in the mesocosms without vegetation while a large fraction of 15N (23-86%) was unaccounted in the planted mesocosms, indicating N gas diffusion from the plant biomass may be a significant removal pathway. Both wetland designs are viable treatment options for N removal but differences in management and maintenance plans are recommended due to the FTWs accumulated more N in their biomass. Furthermore, N processes in two constructed pulse flow wetlands will be impacted based upon contaminants in the landscape (e.g., urban, rural).