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Copper Nanoparticles in Complex Agricultural Matrices: Detection, Quantitation, and Implications.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Copper Nanoparticles in Complex Agricultural Matrices: Detection, Quantitation, and Implications./
作者:	Laughton, Stephanie N.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2020,
面頁冊數:	166 p.
附註:	Source: Dissertations Abstracts International, Volume: 82-03, Section: B.
Contained By:	Dissertations Abstracts International82-03B.
標題:	Environmental engineering. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28029254
ISBN:	9798662582194

Copper Nanoparticles in Complex Agricultural Matrices: Detection, Quantitation, and Implications.
Laughton, Stephanie N.

Copper Nanoparticles in Complex Agricultural Matrices: Detection, Quantitation, and Implications. - Ann Arbor : ProQuest Dissertations & Theses, 2020 - 166 p.

Source: Dissertations Abstracts International, Volume: 82-03, Section: B.

Thesis (Ph.D.)--Carnegie Mellon University, 2020.

This item must not be sold to any third party vendors.

Nanoparticle-enabled agrichemicals are currently in use, despite a dearth of information on the fate of the nanoparticles in agricultural matrices such as plant tissue and soil. Current analytical tools and sample preparation methods for detecting and quantifying nanoparticles in plant tissue have significant limitations in their ability to assess the soluble, agriculturally relevant nanoparticles (NP) in environmental samples. These limitations must be overcome to satisfy the potential concerns of farmers, consumers, and regulators. Additionally, toxicity assays for soluble agricultural NP in soil have not yet been standardized, leading to confusing and sometimes contradictory environmental risk literature. The problem appears to be rooted in the different ways dose has been quantified. Most exposures are measured at a single point in time, rather than over time. This fails to account for the dynamic processes soluble NP undergo in plants and soil occurring at similar time scales to the exposure durations. Further, it could explain some of the inconsistency in soil-based toxicity studies. This dissertation addresses these limitations in three distinct ways.Firstly: Since NP toxicity has been linked to particle size, it is important to be able to measure the particle size distribution (PSD) of NP. Single particle inductively coupled plasma mass spectrometry (spICP-MS) is an analytical tool which enables characterization of composition and particle size for a large sample in a relatively short amount of time. This tool can be applied to characterize metallic nanomaterials after application to plant tissues. However, for moderately water-soluble materials (such as copper- and zinc-based NP), current standard sample preparation methods will dissolve these particles and alter their size distribution. This dissertation aimed to develop a sample preparation method for extraction of soluble NP from plant leaf tissues which preserved the in-situ PSD. This involved evaluation of the applicability of the currently accepted enzymatic digestion method for extraction of CuO NP from lettuce tissues in contrast to a novel solvent digestion method. CuO NP are soluble in aquatic matrices, and their dissolution is enhanced by low pH and organic matter. Thus, enzymatic digestion previously used for insoluble materials proved insufficient. A solvent method (using methanol and sonication) was developed and evaluated instead. It demonstrated the successful extraction of Au, CuO, and ZnO nanoparticles from leaf tissues of three common crop plants without loss of original PSD.Secondly: Application of copper-based nano-enabled products to plant tissues, particularly leafy vegetables such as lettuce, is a potential direct path for consumer exposure to nanomaterials. To inform potential risk assessment for these products, an understanding of the fate and transformation on leaf tissues must be acquired. Utilizing the solvent-based sample preparation method developed in this dissertation, the transformation of three nano-enabled agrichemical products after application to growing lettuce leaves was assessed using spICP-MS. These products included two pristine NP (CuO and Cu(OH)2 NP) and one commercial formulation (Kocide® 3000). The effects of (a) increased time on the leaf after dosing and (b) rinsing of the leaf tissue with tap water at harvest were evaluated. It was shown that, at environmentally relevant dosing concentrations, rinsing causes a significant removal of copper from the leaf tissue for all NP treatments, though the change in the particle size distribution and particle concentration is influenced by the copper formulation. Increased time on the leaf causes a minor downshift of the PSD, though the original amount of copper is retained on the tissue in the absence of washing.Finally: As the toxicity of soluble NP in soil depends significantly on their dissolution and release of Cu ions, organisms can experience different concentrations of NP and/or NP-derived ions over time (i.e. the bioavailable dose varies). The dimension of time is not often considered regarding dose in NP toxicity assessment. Instead one sees attempts to correlate toxicity with a single time point concentration of total or extractable metal. The final part of the research demonstrated that calculating the area under the dissolution curve over the period of exposure (AUC) may better represent the cumulative bioavailable dose. The DTPA AUC correlated strongly with a range of different toxicity endpoints (including biochemical and physiological changes to plants and soil invertebrates) in a meta-data analysis of available literature. Time resolved DTPA extractions of copper from soil are applicable to the range of salt-based and particulate copper agrichemicals in available studies. This could possibly enable regulatory homogenization across different physical states of chemicals. Though more data and method development are needed, this seems to be a promising opportunity to improve understanding of metal NP toxicity testing in soil.

ISBN: 9798662582194Subjects--Topical Terms:

548583
Environmental engineering.
Subjects--Index Terms:

Copper

Copper Nanoparticles in Complex Agricultural Matrices: Detection, Quantitation, and Implications.
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300 $a 166 p.
500 $a Source: Dissertations Abstracts International, Volume: 82-03, Section: B.
500 $a Advisor: Lowry, Gregory;Casman, Elizabeth.
502 $a Thesis (Ph.D.)--Carnegie Mellon University, 2020.
506 $a This item must not be sold to any third party vendors.
520 $a Nanoparticle-enabled agrichemicals are currently in use, despite a dearth of information on the fate of the nanoparticles in agricultural matrices such as plant tissue and soil. Current analytical tools and sample preparation methods for detecting and quantifying nanoparticles in plant tissue have significant limitations in their ability to assess the soluble, agriculturally relevant nanoparticles (NP) in environmental samples. These limitations must be overcome to satisfy the potential concerns of farmers, consumers, and regulators. Additionally, toxicity assays for soluble agricultural NP in soil have not yet been standardized, leading to confusing and sometimes contradictory environmental risk literature. The problem appears to be rooted in the different ways dose has been quantified. Most exposures are measured at a single point in time, rather than over time. This fails to account for the dynamic processes soluble NP undergo in plants and soil occurring at similar time scales to the exposure durations. Further, it could explain some of the inconsistency in soil-based toxicity studies. This dissertation addresses these limitations in three distinct ways.Firstly: Since NP toxicity has been linked to particle size, it is important to be able to measure the particle size distribution (PSD) of NP. Single particle inductively coupled plasma mass spectrometry (spICP-MS) is an analytical tool which enables characterization of composition and particle size for a large sample in a relatively short amount of time. This tool can be applied to characterize metallic nanomaterials after application to plant tissues. However, for moderately water-soluble materials (such as copper- and zinc-based NP), current standard sample preparation methods will dissolve these particles and alter their size distribution. This dissertation aimed to develop a sample preparation method for extraction of soluble NP from plant leaf tissues which preserved the in-situ PSD. This involved evaluation of the applicability of the currently accepted enzymatic digestion method for extraction of CuO NP from lettuce tissues in contrast to a novel solvent digestion method. CuO NP are soluble in aquatic matrices, and their dissolution is enhanced by low pH and organic matter. Thus, enzymatic digestion previously used for insoluble materials proved insufficient. A solvent method (using methanol and sonication) was developed and evaluated instead. It demonstrated the successful extraction of Au, CuO, and ZnO nanoparticles from leaf tissues of three common crop plants without loss of original PSD.Secondly: Application of copper-based nano-enabled products to plant tissues, particularly leafy vegetables such as lettuce, is a potential direct path for consumer exposure to nanomaterials. To inform potential risk assessment for these products, an understanding of the fate and transformation on leaf tissues must be acquired. Utilizing the solvent-based sample preparation method developed in this dissertation, the transformation of three nano-enabled agrichemical products after application to growing lettuce leaves was assessed using spICP-MS. These products included two pristine NP (CuO and Cu(OH)2 NP) and one commercial formulation (Kocide® 3000). The effects of (a) increased time on the leaf after dosing and (b) rinsing of the leaf tissue with tap water at harvest were evaluated. It was shown that, at environmentally relevant dosing concentrations, rinsing causes a significant removal of copper from the leaf tissue for all NP treatments, though the change in the particle size distribution and particle concentration is influenced by the copper formulation. Increased time on the leaf causes a minor downshift of the PSD, though the original amount of copper is retained on the tissue in the absence of washing.Finally: As the toxicity of soluble NP in soil depends significantly on their dissolution and release of Cu ions, organisms can experience different concentrations of NP and/or NP-derived ions over time (i.e. the bioavailable dose varies). The dimension of time is not often considered regarding dose in NP toxicity assessment. Instead one sees attempts to correlate toxicity with a single time point concentration of total or extractable metal. The final part of the research demonstrated that calculating the area under the dissolution curve over the period of exposure (AUC) may better represent the cumulative bioavailable dose. The DTPA AUC correlated strongly with a range of different toxicity endpoints (including biochemical and physiological changes to plants and soil invertebrates) in a meta-data analysis of available literature. Time resolved DTPA extractions of copper from soil are applicable to the range of salt-based and particulate copper agrichemicals in available studies. This could possibly enable regulatory homogenization across different physical states of chemicals. Though more data and method development are needed, this seems to be a promising opportunity to improve understanding of metal NP toxicity testing in soil.
590 $a School code: 0041.
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653 $a Nanomaterials
653 $a Complex agricultural matrices
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710 2 $a Carnegie Mellon University. $b Civil and Environmental Engineering. $3 2097787
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793 $a English
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