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Water Quality Assessment Simulation Program (WASP8): Upgrades to the Advanced Toxicant Module for Simulating Dissolved Chemicals, Nanomaterials, and Solids
Citation:
Ambrose, B., B. Avant, Y. Han, Chris Knightes, AND T. Wool. Water Quality Assessment Simulation Program (WASP8): Upgrades to the Advanced Toxicant Module for Simulating Dissolved Chemicals, Nanomaterials, and Solids. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-17/326, 2017.
Impact/Purpose:
Agency Research Drivers Under the Toxic Substances Control Act (TSCA), the Environmental Protection Agency (EPA) is required to perform new chemical reviews of nanomaterials identified in pre-manufacture notices. Nanomaterials have unique electronic, mechanical and structural properties, which has led to their increased production and use in technological applications. It is unclear, however, what will happen to nanomaterials as they are released into the environment. Currently available environmental fate and transport models, which were developed for traditional contaminants, are limited in their ability to simulate nanomaterials’ environmental behavior. These limitations are due to an incomplete understanding and representation of the processes governing nanomaterial distribution in the environment and by scarce empirical data quantifying the interaction of nanomaterials with environmental surfaces. Science Challenge The goal of this research was address these challenges by developing and parameterizing a widely used water quality model (WASP) so that it would be able to simulate the fate and transport of nanomaterials in surface water systems. WASP is one of the most widely used water quality modeling frameworks in the US and the world. WASP has undergone several updates and upgrades since its original formulation in the 1980s. Research Approach This product incorporates a complete overhaul on the toxicant module in WASP8, upgrading from Fortran77 to Fortran95. We developed WASP8 Advanced Toxicant Module working alongside nanomaterial laboratory researchers to carve out the best implementation of nanomaterial specific governing processes, while maintaining the utility and applicability within the WASP8 framework. Results The redesigned architecture of WASP in WASP8 is a great improvement on WASP7. The newly updated Advanced Toxicant module advances the old toxicant module from only a few chemicals and a few solids, to any number of chemicals, nanomaterials, solids, dissolved organic carbon, and pathogens and salinity and temperature. The functionality of governing processes has similarly been improved, such as having the nanomaterial specific particle attachment process of heteroaggregation incorporated into the model. Additionally, improved algorithms for processes like photo-transformation due to light of various wavelengths (now 10 can be simulated) as well as improved representations of chemical reactions depending on different environmental factors (like oxidants or reductants in a Monod formulation). Anticipated Impact/Expected use Agency Research Drivers Under the Toxic Substances Control Act (TSCA), the Environmental Protection Agency (EPA) is required to perform new chemical reviews of nanomaterials identified in pre-manufacture notices. Nanomaterials have unique electronic, mechanical and structural properties, which has led to their increased production and use in technological applications. It is unclear, however, what will happen to nanomaterials as they are released into the environment. Currently available environmental fate and transport models, which were developed for traditional contaminants, are limited in their ability to simulate nanomaterials’ environmental behavior. These limitations are due to an incomplete understanding and representation of the processes governing nanomaterial distribution in the environment and by scarce empirical data quantifying the interaction of nanomaterials with environmental surfaces. Science Challenge The goal of this research was address these challenges by developing and parameterizing a widely used water quality model (WASP) so that it would be able to simulate the fate and transport of nanomaterials in surface water systems. WASP is one of the most widely used water quality modeling frameworks in the US and the world. WASP has undergone several updates and upgrades since its original formulation in
Description:
The Water Quality Analysis Simulation Program (WASP) is a dynamic, spatially-resolved, differential mass balance fate and transport modeling framework. WASP is used to develop models to simulate concentrations of environmental contaminants in surface waters and sediments. As a modeling framework, it allows users to construct the model design that is appropriate for the system of interest, in one, two, or three dimensions. WASP allows for time-varying processes of advection, dispersion, point and diffuse mass loading, boundary conditions and boundary exchange. WASP can be linked to hydrodynamic and sediment transport models, or the hydrodynamic algorithms within the WASP framework can be used. WASP is one of the most widely used water quality models in the USA and throughout the world. It has been applied in development of Total Maximum Daily Loads (TMDLs); simulation of nutrients in Tampa Bay; and remediation strategies for mercury in the Sudbury River. WASP is an enhancement of the original version developed in the 1980s. Over the years, it has undergone many improvements and enhancements. In July 2017, WASP8 (WASP, v.8.1) was released. It was a complete overhaul and recoding that moved from Fortran77 to Fortran95 to take advantage of many updated features. This release also incorporated a new WASP interface, a new post-processor (WRDB), and the ability to run on a PC or Mac.