Simulating the Fate, Transport, and Transformations of Organic Nanoparticles and their Daughter Products in Surface Waters and Sediments: Combining Laboratory Studies with Process Modeling
Abstract
The unique properties of engineered nanoparticles have led to their increased production and potential release into the environment. Understanding exposure concentrations in aquatic ecosystems is challenging because currently available environmental fate models are limited in their ability to simulate nanoparticles' environmental behavior. This limitation is due to an incomplete understanding and representation of governing processes and by scarce observed data quantifying particle interactions, transformations, and daughter products. The Water Quality Analysis Simulation Program (WASP) has been updated to allow for simulation of nanoparticles environmental fate by defining new state variables and incorporating nanomaterial-specific processes, including hetero-aggregation with particulate matter and photo-transformation. Laboratory studies were performed to provide necessary parameters, including attachment efficiencies and photo-transformation rate constants as well as the formation and yields of low molecular weight products. Our work has focused on organic nanoparticles, particularly multi-walled carbon nanotubes (MWCNT) and graphene oxide (GO). GO has been shown to photo-degrade into reduced GO (rGO) as well as forming Polycyclic Aromatic Hydrocarbons (PAHs). The yields and structures of several PAHs have been identified. This work combines development of the WASP model with laboratory measured parameters to simulate exposure concentrations in surface water and sediments following a hypothetical release of MWCNT and GO from a waste water treatment facility into surface water. Simulations are performed in two rivers (Yadkin River, NC and Brier Creek, GA) and two lakes (Lake Barco, FL and Lake Waccamaw, NC) in the United States. These simulations of MWCNT and GO provide insight into how these nanoparticles might behave in the environment once released, including distance traveled, sediment accumulation, and daughter products that form over time. While this work focuses on nanoparticles, the advanced toxicant module also can simulate other emerging contaminants, such as pharmaceuticals and per- and polyfluoroalkyl substances (PFAS).
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H12F..01K
- Keywords:
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- 0409 Bioavailability: chemical speciation and complexation;
- BIOGEOSCIENCESDE: 1832 Groundwater transport;
- HYDROLOGYDE: 1865 Soils;
- HYDROLOGYDE: 1871 Surface water quality;
- HYDROLOGY