Dissertation
NANOPLASTIC AND NANOMATERIALS IN TERRESTRIAL SYSTEMS: ENVIRONMENTAL CONCERNS AND CHALLENGES
Doctor of Philosophy (PhD), Washington State University
01/2020
Handle:
https://hdl.handle.net/2376/111292
Abstract
Micro- and nanomaterials have always been a part of earth's biogeochemical cycles. Only within the last century has the production of anthropogenic materials in the micro- to nanometer size range become a signicant input to earth's ecosystems. Over the last few decades, much research has been done to characterize how specic micro- and nanomaterials interact with a variety of ecosystems. One source of engineered micro- and nanomaterials to terrestrial environments is the application of biosolids to the soil as a source of plant nutrients
and organic matter. Unplanned addition of engineered materials to the soil may have negative environmental consequences, or could hinder the further use of biosolids as a benecial soil amendment. The overall goal of this dissertation is to assess the potential for micro- and nanoplastic, as well as silver nanoparticles, to accumulate in dryland agricultural soils with 20+ years of biosolids application for fertilizer. We also seek to understand the interaction of these man-made materials with the ecosystem, and develop better methods for their identification and characterization in soil. The results indicate that micro- and nanometer-sized plastic particles accumulate on the surface of Arabidopsis and wheat roots, especially root caps, but no evidence for movement of nanoplastic into the root tissue was found. It is also
shown that silver, in Ag2S nanoparticulate form, has accumulated to concentrations of 1.5 mg silver kg-1 soil after 20+ years of biosolids application. Ecotoxicological effects of Ag2S nanoparticles at that concentration in soil are unknown based on current literature. Finally,
thermal gravimetric analysis (TGA) coupled with mass spectrometry (MS) was unable to detect concentrations of five environmentally relevant plastics in biosolids amended soils, but plastics were detected in biosolids. The detection limit for this method were determined to
be 0.08 wt. % for polystyrene. Alternative extraction, identification, and quantification techniques were also tested and reviewed. The results, taken together, highlight the need for further development of methods to assess the potential environmental risks posed by the
addition of biosolids with associated silver and plastic nano- and microparticles to terrestrial ecosystems.
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Details
- Title
- NANOPLASTIC AND NANOMATERIALS IN TERRESTRIAL SYSTEMS: ENVIRONMENTAL CONCERNS AND CHALLENGES
- Creators
- Stephen Edmond Taylor
- Contributors
- Markus Flury (Advisor)Carolyn I Pearce (Committee Member)Karen A Sanguinet (Committee Member)Indranil Chowdhury (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Crop and Soil Sciences, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 163
- Identifiers
- 99900581497901842
- Language
- English
- Resource Type
- Dissertation