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Responses Of Daphnia Magna To Chronic Exposure Of Cadmium And Nickel Mixtures, Edgar Pérez, Tham C. Hoang
Responses Of Daphnia Magna To Chronic Exposure Of Cadmium And Nickel Mixtures, Edgar Pérez, Tham C. Hoang
School of Environmental Sustainability: Faculty Publications and Other Works
The present study assessed the chronic toxicity of cadmium (Cd) and nickel (Ni) mixtures to Daphnia magna. Using a titration design, Ni concentrations of 20, 40, 80, 100, 120, 140, and 160 μg/L were tested alone and simultaneously titrated in increments against a constant concentration of 1.5 μg/L Cd. The results demonstrated that Cd at 1.5 μg/L was highly toxic to D. magna, and Ni alone concentrations ≥80 μg/L were toxic to D. magna survival, reproduction, and growth. No Ni alone concentration was found to induce a toxic effect on undeveloped embryos and the time to first brood. …
Mchm (4-Methylcyclohexane Methanol) Influences The Predator-Prey Interaction Between Danio Rerio And Daphnia Magna, Anna C. Wagner
Mchm (4-Methylcyclohexane Methanol) Influences The Predator-Prey Interaction Between Danio Rerio And Daphnia Magna, Anna C. Wagner
Electronic Theses and Dissertations
Chemical contamination alters organism-level traits, such as activity and feeding, that can ultimately affect aquatic trophic interactions. Despite the importance of predator-prey relationships in aquatic communities, chemical toxicity is often tested on single species prior to use. For example, 4-methylcyclohexane methanol (MCHM) used in industrial coal-cleaning enters the environment regularly from low-level contamination during disposal and occasionally in high concentrations following accidental spills, but its effects on fish-zooplankton interactions remain unknown. It was hypothesized MCHM exposure affects zebrafish and D. magna swimming behavior differently when exposed individually or together, and ultimately affects their relationship. Zebrafish and D. magna were exposed …
Chronic Toxicity Of Binary‐Metal Mixtures Of Cadmium And Zinc To Daphnia Magna, Edgar Pérez, Tham C. Hoang
Chronic Toxicity Of Binary‐Metal Mixtures Of Cadmium And Zinc To Daphnia Magna, Edgar Pérez, Tham C. Hoang
School of Environmental Sustainability: Faculty Publications and Other Works
The present study characterized the chronic effect of binary‐metal mixtures of cadmium (Cd) and zinc (Zn) on Daphnia magna. The titration design was chosen to characterize the 21‐d chronic effects of the binary‐metal mixtures on survival, growth, reproduction, and metal accumulation in D. magna. Using this design, increasing concentrations of Zn (10, 20, 40, 80, 120, 160, and 200 μg/L) were titrated against a constant concentration of 1.5 μg/L Cd. The results demonstrated that Cd was highly toxic to D. magna. In a mixture with Cd and Zn, sublethal concentrations of 10 and 20 μg/L Zn were …
Hazard Assessment Of A Mixture Of Pharmaceuticals Detected In The Upper Tennessee River Of Daphnia Magna And The Determination Of Riverine Zooplankton Assemblage As It Relates To Chitobiase Activity, Daniel Neil Wolfe
Masters Theses and Doctoral Dissertations
In order to respond to the need for hazard assessment of environmentally relevant pharmaceutical mixtures, 21-d life cycle tests were performed on a mixture of pharmaceuticals found in the Tennessee River using Daphnia- magna as a surrogate. Endpoints measured were time to first brood, reproduction, mortality, and number of neonates produced per adult reproduction day. Reproduction was the only endpoint that showed a significant effect. The LOEC of the pharmaceutical mixture was found at 100 times (100x) greater concentration (p=0.005) than what was detected in the Tennessee River. Similarly, the NOEC was 75x (p=0.150). Single concentrations of pharmaceuticals within the …
The Toxicity Of Carbon Nanotubes To Daphnia Magna, Aaron Edgington
The Toxicity Of Carbon Nanotubes To Daphnia Magna, Aaron Edgington
All Dissertations
A particle is classified as nano in size if it has at least one dimension less than 100 nm which gives them chemical and physical characteristics that are different from the bulk material. Over the last twenty years nanotechnology has exploded as an industry. It has been estimated that there are 1000 consumer products on the market today that contain nanomaterials and 2 million jobs worldwide will be devoted directly to nanotechnology research, development, and product manufacturing by 2015. Carbon nanotubes (CNTs) can be visualized as sheets of graphene rolled into a cylinder. Carbon nanotubes small diameter (nanometer scale) and …
The Effects Of Pulsed Exposures Of Suspended Clay On The Survival, Growth, And Reproduction Of Daphnia Magna, Sarah Robinson
The Effects Of Pulsed Exposures Of Suspended Clay On The Survival, Growth, And Reproduction Of Daphnia Magna, Sarah Robinson
All Theses
Suspended sediments are a natural component of aquatic ecosystems but anthropogenic activity such as land development can result in significant increases, especially following rain events due to surface erosion. Continuous exposures of suspended clay and silt have been shown to effect growth and reproduction of Cladocera, leading to a decrease in population growth rate. The mechanism of clay toxicity in these filter-feeding organisms is clogging of the gut tract resulting in decreased food uptake and assimilation. When placed in clean water, daphnids can purge clay from their gut and recover. In many surface waters, aquatic organisms experience episodic exposures of …
Influence Of Suspended Solids On Acute Toxicity Of Carbofuran To Daphnia Magna: Ii. An Evaluation Of Potential Interactive Mechanisms, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer
Influence Of Suspended Solids On Acute Toxicity Of Carbofuran To Daphnia Magna: Ii. An Evaluation Of Potential Interactive Mechanisms, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer
Steven P. Bradbury
It has been demonstrated that simultaneous exposure of Daphnia magna to suspended solids and a carbamate pesticide potentiates the toxic response to the pesticide. The toxicodynamics between these stressors were investigated to determine possible mechanisms of interaction. Three experimental series were conducted with D. magna to determine: the effect of food availability on carbofuran toxicity; the effect of food availability on jointly administered carbofuran and suspended solids; and changes in the magnitude of effects which can occur with suspended solids of different composition. These experiments demonstrated that both carbofuran toxicity and the joint toxicity of carbofuran and suspended solids to …
Influence Of Suspended Solids On Acute Toxicity Of Carbofuran To Daphnia Magna: I. Interactive Effects, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer
Influence Of Suspended Solids On Acute Toxicity Of Carbofuran To Daphnia Magna: I. Interactive Effects, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer
Steven P. Bradbury
This study explored the effects on Daphnia magna from exposure to the pesticide carbofuran in combination with stress from suspended solids exposure. Our objective was to assess whether suspended solids affects the toxicodynamic response of D. magna to carbofuran. A series of laboratory experiments was performed where animals were exposed to carbofuran concentrations ranging from 0 to 160 mg/l in combination with suspended solids concentrations ranging from 0 to 10,000 mg/l. In the absence of suspended solids, effects of carbofuran were dose dependent and resulted in an EC(sub)50 of 92 mg/l. Exposure to suspended solids, up to extreme levels that …
New Testing Apparatus For Assessing Interactive Effects Of Suspended Solids And Chemical Stressors On Plankton Invertebrates, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer
New Testing Apparatus For Assessing Interactive Effects Of Suspended Solids And Chemical Stressors On Plankton Invertebrates, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer
Steven P. Bradbury
To better predict and interpret the responses of aquatic organisms to environmentally relevant chemical exposures, it is necessary to investigate the combined effects of physical (e.g., suspended solids) and chemical stressors. One of the limitations in investigating suspended solids–chemical interactions has been the lack of an appropriate testing system. The specific objective of the current study was to develop and assess a suspended solids testing apparatus (SSTA) for studies on the combined effects of suspended solids and chemicals on aquatic invertebrates. The SSTA was designed to permit the assessment of varying suspended solids concentrations on Daphnia magna at a constant …