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Full-Text Articles in Physical Sciences and Mathematics

Physiological, Biochemical, And Metabolic Responses Of Wheat (Triticum Aestivum) Exposed To Perfluorooctanesulfonic Acid (Pfos), Polycarp Chidiebere Ofoegbu Aug 2021

Physiological, Biochemical, And Metabolic Responses Of Wheat (Triticum Aestivum) Exposed To Perfluorooctanesulfonic Acid (Pfos), Polycarp Chidiebere Ofoegbu

MSU Graduate Theses

The effects of perfluorooctanesulfonic acid (PFOS) on agricultural plants is a serious environmental concern that needs to be addressed. PFOS is a member of a class of organic chemical compounds known as per and polyfluoroalkyl substances (PFAS). These compounds are utility chemicals in household, commercial, and industrial items, but have become environmental contaminants of global concern. Full lifecycle and short-term exposure studies of wheat grown in soil amended with 0, 25, and 50 mg/kg PFOS were conducted to assess the impacts of PFOS on wheat. PFOS uptake analysis, physiological assays, elemental analysis, and metabolomics were carried out in the full …


Nanomaterials For Double-Stranded Rna Delivery, Stuart Lichtenberg Jan 2019

Nanomaterials For Double-Stranded Rna Delivery, Stuart Lichtenberg

Theses and Dissertations--Plant and Soil Sciences

RNA interference has enormous potential as a potent, specific, and environmentally friendly alternative to small molecule pesticides for crop protection. The use of exogenous double-stranded RNA offers flexibility in targeting and use in crops in which transgenic manipulation is not an option. The combination of RNAi with nanotechnology offers further advantages that are not available with dsRNA alone. In this work, I have evaluated several different combinations of nanomaterials and polymers for use in RNAi-based pest control systems. First, I have characterized the use of chitosan/dsRNA polyplex nanoparticles for gene knockdown using the model nematode Caenorhabditis elegans. Though chitosan/dsRNA …


Influence Of Salinity, Sunlight, And Sediment On The Toxicity Of Pesticides In Three Non-Target Organisms, Emily Noelle Vebrosky Oct 2018

Influence Of Salinity, Sunlight, And Sediment On The Toxicity Of Pesticides In Three Non-Target Organisms, Emily Noelle Vebrosky

LSU Doctoral Dissertations

Pesticides used in the United States must undergo registration by the United States Environmental Protection Agency (USEPA), after a multitude of analyses ranging from environmental fate to aquatic toxicological impacts to human risk exposure. Testing varies for each chemical, some requiring more testing than others. In many cases, environmental factors are restricted in the analysis of chemical behavior and organismal testing is limited to larvae. Many pesticides are formulated to breakdown in the environment by means of photolysis, hydrolysis, or oxidation, either to ensure low-persistence, limited transport, or to form the active ingredient (pro-pesticides). Environmental influences on chemical behaviors include …


Transformations, Bioavailability And Toxicity Of Manufactured Zno Nanomaterials In Wastewter, Sewwandi Rathnayake Jan 2013

Transformations, Bioavailability And Toxicity Of Manufactured Zno Nanomaterials In Wastewter, Sewwandi Rathnayake

Theses and Dissertations--Plant and Soil Sciences

In order to properly evaluate the ecological and human health risks of ZnO Manufactured nanomaterials (MNMs) released to the environment, it is critical to understand the likely transformation products in the wastewater treatment process and in soils receiving biosolids. To address this critical knowledge gap, we examined the transformation reactions of 30 nm ZnO MNMs in single component and multi-component systems, with phosphate and natural organic matter (NOM). We also assessed the influence of nano ZnO transformation on the bioavailability, and toxicity of ZnO transformation products to Triticum aestivum. The data revealed that ZnO MNMs react with phosphate at …


Determination Of Copper Speciation, Bioavailability And Toxicity In Saltwater Environments, Tara N. Tait Jan 2013

Determination Of Copper Speciation, Bioavailability And Toxicity In Saltwater Environments, Tara N. Tait

Theses and Dissertations (Comprehensive)

The speciation of copper plays a strong role in determining bioavailability and toxicity upon copper exposure in marine environments. Specifically, natural organic matter (NOM) can complex with copper, influencing speciation and decreasing bioavailability. The aim of this research was to determine accurate copper speciation values using literature and new techniques and applying the techniques that reflect the most accurate speciation values to investigate the influence of NOM quantity and quality on copper speciation and toxicity. The results from this study will have implications on the development of a marine Biotic Ligand Model (BLM). Free copper was measured using a flow-through …