Toxicology Commons^™

From Sunscreen To Seafood: Tracing The Ecological And Human Health Risks Of Oxybenzone Contamination In Local Fish, Alyssa Brasko

Discovery Day - Daytona Beach

Oxybenzone (benzophenone-3) is a widely used ultraviolet (UV) filter in sunscreens, offering protection against harmful radiation but raising significant environmental concerns due to its persistence and toxicity in aquatic ecosystems. This ongoing study aims to investigate the bioaccumulation and ecological impact of oxybenzone in fish species along Florida’s Space Coast, contributing to a broader understanding of its environmental fate and potential human exposure through seafood consumption. The research will employ advanced analytical techniques, including Gas Chromatography-Mass Spectrometry (GC-MS) and High-Performance Liquid Chromatography (HPLC), to quantify oxybenzone levels in locally sourced fish. Fish samples will be obtained from the non-profit organization …

Fish Tissue Digestion And Microplastic Polymer Identification Protocol Using Open-Source Ftir Database, Shawn L. Kissinger, Vick-Ariel Privert, Jason Bystriansky, Kyle A. Grice

DePaul Discoveries

Microplastic (MP) contamination in aquatic ecosystems poses significant concerns for environmental and public health, as seafood represents a critical food source worldwide. Despite increasing evidence of MP presence in marine organisms, efficient and accessible detection methods remain essential for characterizing contamination patterns and informing regulatory frameworks. This study extracted MPs from brain, gill, intestine, liver, and muscle tissues of gilt-head bream (Sparus aurata) and European sea bass (Dicentrarchus labrax), two commercially important species from the Gulf of Cádiz, Spain, using a NaOH–HNO₃ chemical digestion protocol. Isolated particles were characterized by Fourier Transform Infrared (FTIR) spectroscopy, with …

Acute Effects Of The Psychoactive Pollutant Fluoxetine On The Antipredator Behavior Of The Gulf Killifish (Fundulus Grandis), Semyra Reus

Honors Theses

Pharmaceutical contaminants are increasingly prevalent in aquatic environments, yet their sublethal effects on ecologically relevant behaviors remain poorly understood, particularly in estuarine systems. Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, are of particular concern due to the conserved role of serotonin in regulating behavior across vertebrates. Here, we investigated how acute exposure to environmentally relevant concentrations of fluoxetine influences anti-predator behavior in Gulf killifish (Fundulus grandis), a key estuarine fish commonly found in saltmarsh habitats. Killifish were exposed to control (0 ng/L), low (17.8 ng/L), and high (596 ng/L) fluoxetine concentrations and subsequently tested in the presence …

Muscular Degeneration In Caenorhabditis Elegans By Microplastic And Chemical Exposure Through Locomotion Analysis, Juan Pablo Olvera Rodriguez, Angelica Cue-Leon, David Mares

Posters - 2026

We use Caenorhabditis elegans (C. elegans) as a model organism to investigate the effects of microplastic and chemical exposure on muscle structure and function.

• Microplastics (MP) are pieces of plastic less than 5 μm, and Nanoplastics (NP) are less than 1 μm. Microplastics are man-made pollutants and have been found in the environment and in the food and water sources, including drinks from plastic bottles (Hu, 2020). • Our work relates environmental contamination to potential biological consequences at the muscular level, providing insight into how pollutants may contribute to degenerative damage.

• Polystyrene (PS) MPs alone and combined with …

Imidacloprid Effects On The Survival And Cutaneous Microbiome Of Northern Leopard Frogs, Evelyn Margaret Osterloo

Honors Thesis

Amphibians are experiencing population declines due to habitat loss, climate change, and diseases, particularly chytridiomycosis caused by the fungus Batrachochytrium dendrobatidis. Protection from this fungal infection stems from the cutaneous microbiome. Pesticides have been shown to affect amphibians in a variety of ways, including reducing survival, locomotor performance, and accumulation in body tissues. Pesticides may also lead to changes in the cutaneous microbiome affecting amphibians who rely on these organisms as an anti-Bd defense mechanism. To investigate the effect of imidacloprid, a neonicotinoid insecticide, Northern Leopard frogs (Lithobates pipiens) were subjected to sublethal concentrations (control = …

Trophic Structure And Mercury Bioaccumulation In Walleye And Yellow Perch In The Upper And Lower Red Lake Basins, Marissa Pribyl

Biology Graduate Theses

Mercury is a persistent global contaminant that biomagnifies through aquatic food webs, with dietary and environmental factors serving as the primary drivers of accumulation in fishes. Trophic structure and methylmercury dynamics in Walleye (ogaa; Sander vitreus) and Yellow Perch (asaawens; Perca flavescens) were investigated in the Upper and Lower Red Lake basins in Red Lake, Minnesota, during 2024-2025. Diets of Walleye and Yellow Perch were assessed through stomach dissections, and tissue samples from both species were analyzed for total mercury concentrations. Additional analyses included shiners (gigoozens; Notropis spp., Hudsonius spp.) along with a variety of freshwater fish and …

Conditioned Feed Aversion As A Means Of Conditioning Livestock To Avoid Consuming Toxic Plants Growing In South Africa : An Overview, Leendert D. Snyman, Frederick D. Provenza

Poisonous Plant Research (PPR)

Significant economic losses to the livestock industry are caused by the ingestion of toxic plants in South Africa, among which the most dangerous ones are Moraea pallida (geeltulp), Urginea/Drimea sanguinea (rooislangkop), Senecio latifolius (Staggers Ragwort), and Geigeria ornativa (vermeerbos). Conditioned feed aversion is a potential means to address this issue. Treating animals with an aversive substance along with an extract of the sensory characteristics of a specific plant conditions animals to avoid the plant. Geigeria ornativa, unlike the other three plants, is non-aversive. Following treatment for aversion, the induced aversion fades with time and eventually breaks down. Continuous exposure …

Hfpo-Da Aquatic Toxicity And Bioaccumulation, Bailey Dawn Rappold

Theses, Dissertations and Capstones

Per- and polyfluoroalkyl substances (PFAS) have been detected globally in environmental media and biota. Legacy compounds PFOA and PFOS have been observed to be toxic and bioaccumulative in low doses and have been removed from production and industrial processes. Replacement PFAS chemicals are less understood and present a gap in current knowledge in their toxicological effects. This research utilized extended chronic toxicity studies to assess the impacts of HFPO-DA, a short chain replacement PFAS, on the standard aquatic toxicology organism Pimephales promelas. Organisms were exposed for 29 to 30 days at environmentally relevant concentrations of the toxicant, 7.8125 ng/L …

Neonicotinoid Bioaccumulation In Bluegill And Bullhead Within Lake Julia And Lake Zumwalde, Jake Stuber

Journal of Earth and Life Science

Brown Bullhead Ameiurus nebulosus, Yellow Bullhead Ameiurus natalis, and Bluegill Lepomis macrochirus are unique in their stark differences. Bullhead are scaleless bottom feeders that can tolerate high pollution and low O₂ conditions. In contrast, Bluegill are scaled, aggressive nesters and are less tolerant of high pollutants or low-oxygen conditions. Among these pollutants include a class of chemicals called neonicotinoids (hereafter referred to as neonics). Neonics are a class of insecticides primarily used within agriculture and pest management. Due to the effectiveness, application has escalated on a global scale. They have been well documented by many toxicology assessments. …

Fluctuation Of Organochlorine Concentrations In Bull Sharks At Different Life Stages, Mackenzie R. Phillips

Dissertations, Master's Theses and Master's Reports

For Carcharhinid species such as the bull shark (Carcharhinus leucas), the maternal offloading of nutrients is essential for pup development and growth, however, significant amounts of OCs are also transferred. As a top predator in aquatic food webs, bull sharks can potentially bioaccumulate high concentrations of pollutants such as dichloro-diphenyl-trichloroethane (DDT) that biomagnify through aquatic food webs. These pollutants are also hydrophobic and fat soluble and therefore pose toxicity risks to developing young bull sharks. In this study, liver tissues collected from juvenile bull sharks inhabiting Florida’s coastal waters were analyzed for a suite of organochlorine pesticides (OCs) …

Spiders In The World Of Pesticides: A Review, Jackson L. Mendillo

Williams Honors College, Honors Research Projects

Pesticides and other agrochemicals have varying effects on spiders depending on their mechanism of action and dosage, ranging from behavioral changes and ataxia, to reproductive changes and physiological stress, to lethal non-target effects. Additionally, peptide Hv1a has promising effects as a more narrow-spectrum pesticide.

Methodology For Environmental Toxicology: Assessing Feeding And Rearing Strategies In Largemouth Bass (Micropterus Nigricans) Larvae, Amber Hitchins, Hannah Mcneese, Deise Cruz, Andrew Todd, Maria Sepúlveda, Tyler Hoskins

Discovery Undergraduate Interdisciplinary Research Internship

Poly- and perfluoroalkyl substances (PFAS) are an anthropogenic group of chemicals known for their persistence in the environment and their potential to bioaccumulate. PFAS can bioaccumulate in largemouth bass (Micropterus nigricans), yet the effects of exposure on bass larvae are unknown. While largemouth bass are commonly raised for aquaculture, techniques for rearing bass which enable controlled experiments at known densities, a necessity for toxicity studies, are poorly understood. Furthermore, the live prey typically used in existing approaches are not suitable for PFAS studies due to high background concentrations. The objective of this project was to assess different venues …

Continuous Exposure To An Aversive Mixture: A Means Of Maintaining Aversion In Sheep Averted To Geigeria Ornativa O. Hoffm. (Vermeerbos) - An Assessment, Leendert D. Snyman

Poisonous Plant Research (PPR)

Establishing aversion to Geigeria ornativa only lasts for some time, after which the induced aversion disappears and sheep start eating G. ornativa again. This behavior is aggravated by the social influence of non-averted sheep in mixed grazing situations. Exposing sheep continuously to a so-called “aversive mixture”, containing an aversive substance (lithium chloride) and the sensory characteristics of the plant (hexane extract of G. ornativa) mixed with a tasty meal (maize meal), following an initial aversion treatment, resulted in sustained aversion to G. ornativa in the field. This method proved to be applicable to mixed grazing situations with averted and …

Ms Environmental Biology Capstone: Evaluating Environmental Risks And Conflicts In Golf Course Landscapes, Meredith Boos

Regis University Student Publications (comprehensive collection)

1) This review investigates the relationship between pesticide use on golf courses and in agriculture to determine whether the adverse health effects documented in agricultural settings also apply to golf course environments. While the negative health effects from agricultural pesticide use are well established, golf courses use pesticides with greater frequency and intensity, suggesting a potentially higher exposure risk for both workers and players.

2) This study proposes methods to quantify pesticide bioaccumulation on golf courses and adjacent lands. We hypothesize that areas surrounding golf courses will exhibit a spatial gradient of pesticide accumulation, increasing with proximity to treated sites …

The Relationship Between Plant Density And Microplastic Concentration In The Water In Lake Bemidji, Mn, Arian Garcia

Journal of Earth and Life Science

Microplastics, plastic particles smaller than 5 mm, are an increasing environmental threat, particularly due to their widespread distribution and toxicity. While much research has focused on larger freshwater and marine ecosystems, the presence and impacts of microplastics in smaller inland lakes remain less understood. This study investigates the relationship between plant density and microplastic concentrations in Lake Bemidji, a smaller freshwater lake. A total of 30 water samples were collected across varying vegetation conditions, ranging from open water (0%) to 90% plant coverage. Microplastics were identified and categorized into six morphological types: fibers, fragments, films, spheres/beads, and foam. The samples …

Evaluating The Chemical Reactivity Of Wildfire-Derived Dissolved Organic Molecules: Glutathione Binding Through Kendrick Mass Defect Analysis, Hannah M. Hamontree, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

The emerging risks to organisms of pyrogenic-derived dissolved organic matter (PyDOM) from forest fires are of concern due to its toxic and mutagenic potential (e.g., pro-oxidative responses in fauna through the depletion of glutathione, a nitrogen- and sulfur-containing tripeptide found in cells). This study simulates this phenomenon in a laboratory setting by identifying bonding between reduced l-glutathione and organic molecules in leachates from environmentally weathered biomass samples (charred and uncharred) using Kendrick Mass Defect (KMD) analysis from formula lists obtained from negative-mode electrospray ionization-Fourier transform-ion cyclotron resonance-mass spectrometry ((-)ESI-FT-ICR-MS). These formula lists reveal a 10-fold increase in nitrogen- and sulfur-containing …

Investigating Nekton Response To Changing Salinities In The Mississippi Sound: An Experimental And Statistical Approach, Adam Murray

Master's Theses

The Mississippi Sound provides nursery habitats for many coastal species and is recognized for its commercial fisheries. Previous freshening events linked to the Bonnet Carré Spillway, a Mississippi River flood diversion structure, proved catastrophic for oyster populations in the Mississippi Sound, but effects on mobile fish and shellfish species are not well-defined. The planned Mid-Breton Sediment Diversion (MBSD), an initiative to combat wetland loss, is also forecasted to lower salinities in the region, increasing the need to better understand responses of commercially and ecologically important species to freshening events. The objective of this study was to characterize effects of salinity …

Rabbit Control: Bait Products, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity factsheets

This factsheet is part of the bait and poison directory for vertebrate pests in Western Australia (WA). It provides information on bait, poison, and toxin (bait) products available for use in WA to control rabbits (Oryctolagus cuniculus).

For information on how to access bait, poison and toxin (bait) products, training required, animal welfare considerations and legal requirements, refer to the Bait and poison directory for vertebrate pests’ page on the website at dpird.wa.gov.au. Information on bait, poison, and toxin (bait) products available for use in WA for rabbits, is provided below.

Rabbit Control: 1080 Versus Pindone, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity factsheets

There are two toxins available for controlling pest rabbits in Western Australia: 1080 and pindone. This factsheet provides a brief summary of the main characteristics of both vertebrate pesticides. 1080 is generally the preferred toxin for rabbit control in Western Australia (WA).

Any attempt to reduce the impact of rabbits on the productivity of any agricultural enterprise (for example, pasture, crops, tree farms, horticulture) should be undertaken as part of a pest management plan.

This strategy should be proactive rather than reactive to a problem. It should also include a long term strategy for dealing with potential rabbit damage, including …

Rabbit Control: Fumigation, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity factsheets

Fumigation for rabbit control involves the introduction of poisonous gas into a warren. It is one of the best control methods to use where low numbers of rabbits live in a few widely scattered warrens. The threat to non-target animals is minimal. This factsheet should be read in conjunction with registered product labels and directions for use. Check the Department of Health, Western Australia website (health.wa.gov.au) for public health requirements for the use of phosphine fumigation.

Fumigation may be used in areas where access is limited, such as fence lines, around trees, and on riverbanks, but it may be difficult …

Toxicosis From Range Lupine Ingestion In A Research Herd Of Rafter 7 Merino Sheep, Benjamin J. Weigler, Walter F. Mandeville Iii, Scott Huber, Gary Mccuin, Fabrizio Caragena, Daniel D. Cook, Stephen T. Lee, Chris A. Pritsos

Poisonous Plant Research (PPR)

An outbreak of lupine alkaloid neurotoxicosis and death occurred in sheep grazed on rangeland areas of the Nevada Great Basin during the summer of 2023. Overall, 97 sheep died despite veterinary supportive care. Lupinus argenteus var. utahensis was implicated as the causative plant with high levels of lupanine (11.5 µg/mg) and spartiene (13.7 µg/mg) in collected and archived samples. Previous reports of sheep deaths due to lupine ingestion have not been recorded in this region. An increased abundance of the number plants producing seed pods having a high alkaloid content may have been associated with abnormally elevated levels of precipitation …

The Interaction Of Sodium Fluoride And Sodium Selenate On The Developmental Toxicity To Xenopus Laevis And Ambystoma Maculatum Embryos, Shelby Wolfram

Theses

Amphibians play critical roles in the environment's wellness. Fluoride (F) is a widely existing environmental pollutant. It is commonly known for being added to drinking water and as a topical dose on teeth. Selenium (Se) can be found in organic and inorganic forms in nature. Many different fertilizers, pesticides, insecticides, and fungicides contain sodium selenate in them. The range selenium has between deficiency and toxicity is narrow, meaning excess exposure could cause various adverse effects in aquatic organisms. Xenopus laevis is a standard model for developmental toxicity due to being minimal maintenance, cost efficient, and having transparent embryos. Xenopus makes …

The Effects Of Length, Weight, Age, And Gender On Mercury Concentrations In Burbot In North-Central Minnesota Lakes, Liam Hanley

Journal of Earth and Life Science

Burbot Lota lota in north-central Minnesota lakes have the potential to reach large sizes and consume large volumes of prey. This caveat may make burbot susceptible to higher rates of biocontamination, bioaccumulation and biomagnification. The objective of this study was to determine how changes in age, length, gender, weight, and lake affect total mercury concentrations in burbot. In this experiment 28 burbot were angled from three lakes: Cass (n = 17), Winnibigoshish (n = 4), and Bad Medicine (n = 7). Then tissue samples were taken from each fish and were lyophilized and homogenized. Homogenized tissue samples were analyzed by …

Aversion Properties Of Retrorsine, Retrorsine Nitrogen Oxide And Frosted Senecio Latifolius, Leendert D. Snyman

Poisonous Plant Research (PPR)

Two pilot trials, investigating the aversive properties of retrorsine and retrorsine nitrogen oxide and that of frosted Senecio latifolius, were executed. Retrorsine and retrorsine-NO (the toxic principles of Senecio retrorsus), unlke sceleratine-NO (the toxic principle of another hepatotoxic pyrrolizidine alkaloid containing plant, namely S. latifolius), were not capable of establishing aversion when given to a sheep. Frosted S. latifolius given to a sheep also did not induce aversion. However, a sheep averted to S. latifolius (non-frosted) refused eating frosted S. latifolius.

Sceleratin Nitrogen Oxide As Aversive Agent In Conditioning Livestock To Avoid Senecio Latifolius, Leendert D. Snyman

Poisonous Plant Research (PPR)

Sceleratine nitrogen oxide, when administered together with a dichloromethane extract of Senecio latifolius, successfully conditioned cattle and sheep to avoid milled freeze dried S. latifolius mixed with maize meal. This treatment was effectively applied in conditioning steers to refuse eating S. latifolius grown in pots.

Isolation Of The Toxic Principle Of Senecio Latifolius By Means Of The Sensory Receptors Of Sheep, Leendert D. Snyman

Poisonous Plant Research (PPR)

The aversive substance of Senecio latifolius was isolated by means of the sensory receptors of sheep averted to S. latifolius. Chemical fractions refused due to the presence of the aversive substance sensed by the sheep were fractionated until a purified substance had been isolated. Nuclear magnetic resonance (NMR) analysis of the purified substance showed it to be sceleratine nitrogen oxide, the toxic principle of S. latifolius.

Linking The Metabolic And Ecological Fate Of Caribbean Ciguatoxins And Related Neurotoxins In Reef Herbivores, Jessica K. Gwinn

Graduate Theses and Dissertations (2019 - present)

Ciguatera poisoning (CP) is one of the most prominent seafood-borne illnesses worldwide, affecting between 25,000–500,000 people annually. Ciguatera is caused by the ingestion of seafood contaminated with algal-derived ciguatoxins (CTX), the precursors of which are produced by benthic and toxigenic dinoflagellates in the genera Gambierdiscus and Fukuyoa. These compounds enter marine food webs through herbivory and are subsequently transferred to higher trophic levels, undergoing complex metabolic biotransformations, which produce structurally related CTX derivatives. Consumption of CTX induces a variety of severe neurological, gastrointestinal, and/or cardiovascular symptoms beginning within hours and lasting for weeks to months following exposure. Despite the impact …

Telomeres: A Tool To Assess The Impacts Of Mining Contaminants On Riparian Songbirds, Lillian Krach, Bridger Creel, Megan Fylling, Zac Cheviron, Creagh Breuner

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Mining has left massive environmental and physical scars across the landscape. Aquatic and riparian landscapes in particular have been significantly impacted by traditional mining practices. Waste products left over from hard-rock mining leech heavy metals onto the landscape and these metals spread from headwater streams to major waterways (Lottermoser 2010). Heavy metals have been shown to cause physiological stress and challenges to organisms depending on the metal and the concentration (Baos et al. 2019, Boyd & Rajakaruna 2013). While some mining-impaired areas have undergone restoration efforts, is it enough? Typical restoration methods replace the contaminated floodplain, but not the riverbed …

Assessment Of Spilled Toxic Bait By Wild Pigs And Potential Risk To Non-Target Species, John C. Kinsey, Justin A. Foster, Nathan P. Snow, Jason D. Wishart, Linton D. Staples, Janis K. Bush, Kurt V. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Background

In 2018, a sodium nitrite (SN)-based toxic bait for invasive wild pigs (hereafter wild pigs; Sus scrofa), was evaluated to determine its effectiveness in reducing local wild pig populations in Texas. Localized population reductions of > 70% were achieved, but spillage of bait outside wild pig-specific feeders (bait stations) caused by feeding wild pigs resulted in the deaths of non-target animals. To evaluate risks to non-target animals, we tested whether bait presentation influenced the total amount of bait spilled by wild pigs and estimated the associated risk to non-target species.

Results

We found that bait spilled outside bait stations …

Bioaccumulation Of Polychlorinated Biphenyl Compounds And Mercury In A Mining Impacted Aquatic Ecosystem, Michelle Bollini

Dissertations, Master's Theses and Master's Reports

The Keweenaw area continues to be influenced by the century of copper mining that ended nearly 50 years ago. This project is focused on Torch Lake, an aquatic ecosystem that has been heavily impacted by mining waste disposal. The watershed has been impaired by mine discharge and tailings, smelter and smokestack plumes, and poor waste disposal practices. The lake is listed as a Great Lakes Area of Concern with beneficial use impairments of restrictions on fish consumption and a degraded benthic community. Polychlorinated biphenyl compounds (PCBs) and methylmercury (MeHg) are persistent, bioaccumulative, and toxic substances (PBTs). These contaminants pose threats …