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Simulating the Fate and Transport of Carbon-based Nanomaterials Across Different Aquatic Ecosystems
Citation:
Avant, B., Chris Knightes, R. Zepp, D. Bouchard, X. Chang, H. Hsieh, Matt Henderson, J. Spear, Brad Acrey, AND Y. Han. Simulating the Fate and Transport of Carbon-based Nanomaterials Across Different Aquatic Ecosystems. 2018 AGU Fall Meeting, Washington, DC, December 10 - 14, 2018.
Impact/Purpose:
Presented at the 2018 AGU Fall Meeting
Description:
The widespread industrial applications of carbon-based nanomaterials (CNMs) have caused a rapid increase in their production over the last decades. However, toxicity of these materials is not fully known and still being investigated for potential ecological health risks. Detecting CNMs in the environment using current analytical methods is problematic, making environmental fate and transport modeling a practical way to estimate CNM environmental concentrations necessary for guiding management practices and developing legislative regulation. The Water Quality Analysis Simulation Program 8 (WASP8) is a dynamic, spatially resolved fate and transport model for simulating exposure concentrations in surface waters and sediments. Recently, WASP has been updated to incorporate processes for simulating the fate and transport of nanomaterials including heteroaggregation and phototransformation. Concentrations of multiwalled carbon nanotubes (MWCNTs), graphene oxide (GO) and its phototransformed product, reduced graphene oxide (rGO), are simulated in the water column and sediments of four aquatic systems in the southeastern United States. Sites include a seepage lake, a coastal plains river, a piedmont river, and an unstratified wetland lake. A hypothetical 50-year release is simulated for each site-nanomaterial pair to analyze CNM distribution between the water column and sediments. 99% of all nanomaterial mass released into each system is lost through advection without heteroaggregating and depositing in the sediments. However, significant accumulation in the sediments does occur over long periods of time. Results show that lakes accumulated higher concentrations of rGO compared to GO whereas rivers had the opposite result. Simulations provide recovery periods of 37+ years for lakes and 1-4 years for rivers to reduce sediment CNM loads by 50% suggesting CNMs will have potential long-term ecological effects.
