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Modeling the Fate and Transport of Two Nanometal Oxides in Multiple Aquatic Systems
Citation:
Ross, B. AND Chris Knightes. Modeling the Fate and Transport of Two Nanometal Oxides in Multiple Aquatic Systems. American Geophysical Union Fall Meeting 2022, Chicago, IL, December 12 - 16, 2022.
Impact/Purpose:
Nanomaterials are a useful class of chemicals, due to their special properties. The use of nanomaterials have increased over the past years, and as such have increased the potential release into the environment. Understanding how these chemicals move and transform within the environment improves our understanding of potential harm to wildlife and humans. One class of nanaomaterials includes metal oxides. Nanomaterial copper oxide and zinc oxide have antimicrobial properties. They have become incorporated into paints and applied to boats to reduce microbial fouling of the boat material. This work investigates using mathematical models and software to predict the release of nanometal oxides from boats and dissolving into their ionic forms (copper and zinc) to investigate the concentrations the occur over time in the water column and sediments. This work investigates three different types of water bodies: a reservoir, a river, and a harbor.
Description:
Engineered nanomaterials (ENMs) have emerged as their own unique class of contaminants to the environment, due to their increased use and production over the past several decades. ENMs vary in their composition and function and are used in a wide variety of industrial applications. Nanometals, a class of ENMs, are of particular concern for ecosystems, because unlike carbon-based materials, metals are conserved in the environment. Two nanometals that are frequently used in aquatic settings are nano copper oxide (nanoCuO) and nano zinc oxide (nanoZnO). NanoCuO and nanoZnO are active ingredients in many antifouling boat-bottom paints and lumber preservatives. NanoZnO is also used in many sunscreen products, due to its capabilities for absorbing, reflecting, and scattering ultraviolet light. In addition to these products releasing nanoCuO and nanoZnO into surface waters, both nanometals can also dissolve to produce Cu2+ and Zn2+, respectively. Both nanometals and their ionic forms have proven toxic to some aquatic organisms. Despite the widespread use of nanoCuO and nanoZnO, few studies have evaluated their behavior in environmental systems. In this study, we used the Water Quality Analysis Simulation Program (WASP, version 8.4) to investigate the fate and transport of nanometals and their dissolution products in three different aquatic environments. Specifically, we modeled nanoCuO, nanoZnO, Cu2+, and Zn2+ in the surface water and sediments of a river (Merrimack River, MA, USA), a thermally stratified lake (Quabbin Reservoir, MA, USA), and an estuary (Wickford Harbor, RI, USA). We targeted boat-bottom paints as our source for nanoCuO and nanoZnO in Quabbin Reservoir and Wickford Harbor, as both waterbodies are frequented regularly by recreational boaters. To evaluate an alternative release method, we simulated nanoCuO and nanoZnO concentrations resulting from wastewater treatment plant discharge into the Merrimack River. WASP has recently been updated to include an Advanced Toxicant module, which is capable of modeling heteroaggregation and the transformation of ENMs into chemical solutes. Through this study, we hope to further an understanding of the implications of nanoCuO and nanoZnO release into the environment.
