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Simulating the Fate and Transport of Nanoparticles and Their Reaction Products in Surface Waters Using the Water Quality Analysis Simulation Program 8 (WASP8)
Citation:
Han, Y., Chris Knightes, R. Zepp, D. Bouchard, X. Chang, H. Hsieh, B. Avant, Matt Henderson, J. Spear, AND Brad Acrey. Simulating the Fate and Transport of Nanoparticles and Their Reaction Products in Surface Waters Using the Water Quality Analysis Simulation Program 8 (WASP8). 2018 iEMSs Conference, Fort Collins, CO, June 24 - 28, 2018.
Impact/Purpose:
Presented at the to 2018 iEMSs Conference
Description:
The production of graphene oxide (GO) nanoparticles increased appreciably in recent years. GO also has been found to be the most toxic nanoparticles among graphene-based nanoparticles. Sunlight exposure induces GO phototransformation in surface waters, resulting in products that include reduced GO (rGO) and polycyclic aromatic hydrocarbons (PAHs). The Water Quality Analysis Simulation Program (WASP) is one of the most widely used water quality models and has recently been updated (WASP8) to include algorithms for simulating the fate and transport of engineered nanoparticles in surface waters. This study simulates the fate and transport of GO nanoparticles and their major phototransformation products, rGO and PAHs, in a river located in southeastern U.S.A. (Brier Creek, GA). We specifically investigated the influences of three important processes on the fate and transport of GO: (1) light attenuation, (2) phototransformation, and (3) heteroaggregation. Phototransformation of GO in surface waters is influenced by depth-dependent attenuation of the light intensity and wavelength changes in the water column. Heteroaggregation of nanoparticles with suspended solids is acknowledged as the dominant process for their deposition from the water column into bottom sediments. The fate and transport of GO and its photoproducts are simulated for 100 years in this study. Results indicate that phototransformation strongly affects distribution of graphene oxide and their phototransformation products by enhancing their heteroaggregation and deposition into bottom sediments. These changes in GFN distributions are discussed in the context of risk assessment for a GO release to a surface water.
