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Full-Text Articles in Physical Sciences and Mathematics
Responses Of Target And Non-Target Species To Algaecide Exposures, Alyssa Calomeni
Responses Of Target And Non-Target Species To Algaecide Exposures, Alyssa Calomeni
All Theses
Laboratory experiments are often used to predict the responses of target and non-target species to chemical exposures in the field. In the first two experiments of this thesis, a rigorous evaluation of six algal viability measures was conducted. A definitive evaluation of the algal response measures was conducted using heat treatment to create known live: dead cell suspensions. Results from the response measures were compared to the known viability of the cell suspensions to determine their variance and accuracy. Copper-based algaecides were then used as a more realistic exposure to test the algal viability measures. When algal viability measures had …
Prevention Of Iron- And Copper-Mediated Oxidative Dna Damage By Neurotransmmitters And Related Compounds: Evidence For Metal Binding As An Antioxidant Mechanism, Carla Garcia
All Theses
An array of health concerns have been attributed to oxidative DNA damage from the hydroxyl radical (*OH), and the presence of the most biologically available metals iron and copper perpetuate the production of this radical through the Fenton and Fenton-like reactions, respectively. The concentrations at which flavonol and polyphenol antioxidants prevent 50% of DNA damage (IC50) were measured using gel electrophoresis assays upon Fe(II)/H2O2- and Cu(I)/H2O2-mediated DNA damage (Chapter 2). Results show that catechol- and gallol-containing antioxidants differ greatly in preventing DNA damage by Cu(I)/H2O2, compared to Fe(II)/H2O2, behavior that was explained using electron paramagnetic resonance spectroscopy. Semiquinone and other …
Recovery Of Fathead Minnows (Pimephales Promelas) Following Episodic Copper Exposure: A Biochemical, Physiological, Individual, And Population Perspective, Holly Zahner
All Dissertations
The US EPA utilizes the Biotic Ligand Model (BLM) when developing site-specific water-quality criteria for copper. The BLM was calibrated using toxicity data from fixed duration continuous exposures (48 or 96h LC50). However, exposures of copper in natural aquatic systems typically vary in concentration, duration, and may occur multiple times over the life-span of an organism. Additionally, organisms will experience periods in copper free water, potentially allowing them to detoxify and recover homeostasis. Yet, the BLM framework does not consider brief exposures (<24h), multiple exposures, latent responses, or organism recovery, potentially resulting in an inaccurate assessment of exposure toxicity. A recently proposed physiologically-based addition to the BLM will extend the applicability of the framework to brief, multiple pulse copper exposures. Thus, the overall goal of this research was to characterize the recovery of larval Pimephales promelas following episodic copper exposure at a biochemical, physiological, individual, and population level.
The response of whole-body sodium, whole-body Na+/K+-ATPase, and whole-body carbonic anhydrase in larval P. promleas was quantified …
Responses Of Problematic Cyanobacteria To Exposures Of Copper Containing Algaecides, O'Niell Tedrow
Responses Of Problematic Cyanobacteria To Exposures Of Copper Containing Algaecides, O'Niell Tedrow
All Theses
Cyanobacteria (blue-green algae) are associated with production of potent hepatotoxins (Microcystis; microcystin) and dense surface and benthic mats (Lyngbya), which impede critical water resource usages. Water resource managers are in need of effective and efficient treatment techniques for these problematic algae in field situations. Applications of algaecides are considered in situations where algal problems become acute or when critical water usages are threatened. However, laboratory data are needed that accurately predict responses of algae prior to field-scale algaecide applications. Site water and algae were used in laboratory algal toxicity experiments to predict responses of the target alga following an algaecide …