Skip to main content
ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #425836
Research Project: Managing Manure as a Soil Resource for Improved Biosecurity, Nutrient Availability, and Soil Sustainability

Location: Agroecosystem Management Research

Title: Impact of UV weathered polystyrene and polyethylene microplastics on microbially mediated nitrate reduction in floating treatment wetlands

Author
item SUTTON, MEREDITH - University Of Nebraska
item Miller, Daniel
item MESSER, TIFFANY - University Of Kentucky
item BARTELT-HUNT, SHANNON - University Of Nebraska

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/30/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Floating treatment wetlands are a remediation option for waterbodies that receive nutrient pollution from agricultural and urban sources. Microplastics, a contaminant of emerging concern, are also prevalent in these sources and have the potential to alter microbially mediated nitrogen transformation, thus impacting the effectiveness of floating treatment wetlands. Previous experiments using virgin polyethylene and polystyrene microplastics to look at the influence of added microplastics on potential denitrification in floating wetland systems found an increase or decrease in the potential denitrification rate dependent on microplastic size. This research indicates the potential for microplastic influence in floating wetland systems but further exploration is needed to consider the impacts of altered surface characteristics due to environmental weathering of microplastics and the mechanisms causing the observed changes in potential denitrification. To create more environmentally relevant microplastics, the surface of polyethylene (200 µm) and polystyrene (200 µm and 30 µm) microspheres were weathered with simulated sunlight via xenon arc lamp over a spectral range of 300 – 800 nm at an irradiance of 650 W/m2 and a 65 oC BST for 30 days (720 hrs). Weathered microplastics were evaluated for changes in surface characteristics after the full weathering period. Rate of nitrate reduction was assessed for both weathered and virgin microplastics over two concentrations (1 mg/L and100 mg/L). Microplastics were incorporated into microcosms with aggregated root samples collected from floating treatment wetland mats and monitored over five days to observe changes in nitrate concentration in the microcosm. Results from this research will help inform function and denitrification potential of floating treatment wetlands placed to provide remediation in polluted waterbodies as well as contribute to potential trends on the impact of microplastic presence in environments that host similar denitrifying microbial communities such as natural wetlands and wastewater treatment plants.