Publications by authors named "Rachel A Hauser-Davis"

Persistent organic pollutants (POPs) are ubiquitous in the environment and display the capacity to bioaccumulate in living organisms, constituting a hazard to both wildlife and humans. Although restrictions have been applied to prohibit the production of several POPs since the 1960s, high levels of these compounds can still be detected in many environmental and biological matrices, due to their chemical properties and significantly long half-lives. Some POPs can be passed from mother to the fetus and can gain entry to the central nervous system (CNS), by crossing the blood-brain barrier (BBB), resulting in significant deleterious effects, including neurocognitive and psychiatric abnormalities, which may lead to long-term socio-economic burdens.

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DNA integrity is crucial for organismal health, and assessing DNA damage in aquatic organisms is essential for identifying environmental threats and informing conservation efforts. Pollutants such as metals, hydrocarbons, agrochemicals, pharmaceuticals, and climate change are linked to genetic damage, oxidative stress, and mutagenesis in several species, such as elasmobranchs (sharks and rays). Most studies focus on bivalves, crustaceans, and bony fish, with fewer assessments being carried out in cartilaginous fish.

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Anthropogenic activities have increasingly contaminated aquatic ecosystems worldwide, requiring the development of adequate methods to assess the effects of environmental pollution on aquatic biota. Currently, ecotoxicological research on fish is largely based on in vivo studies, many times using post-mortem fish samples bought in fish markets or obtained through capture-and-release programs. However, such samples provide a narrow window to the cellular and molecular processes that occur to fish upon exposure to pollutants and other toxicants or pathogens.

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Elasmobranchs, including sharks, rays, and skates, are a global protein source but face threats from overfishing and population declines. Despite their lower market value, increased consumption raises sustainability and public health concerns. Commonly landed species like the Blue Shark, Shortfin Mako, and Spiny Dogfish are particularly vulnerable to bioaccumulation of metals such as mercury (Hg), lead (Pb), cadmium (Cd), and arsenic (As), posing health risks to consumers.

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Sharks, are highly vulnerable to fishing pressures, a key factor in their global population decline. Chemical pollution, however, especially metal and metalloid contamination, poses significant additional risks. Of around 520 shark species, about 170 are threatened, including the Sphyrna genus (hammerheads).

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The Eastern Mediterranean Sea (EMS) exhibits high temperature and salinity, low levels of biologic production and is considered oligotrophic. Nonetheless, it is also a hotspot of biodiversity, with several important endangered flagship species, including several species of sea turtles. These turtles serve as bioindicators for the health of their ecologic systems, due to changes in diet, habitat and migration patterns that characterize different stages in their lives.

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Cocaine and its primary metabolite, benzoylecgonine, have been recently detected in sharks, indicating a growing concern over marine drug pollution. The presence of this drug in marine fauna poses risks such as physiological stress, impaired growth, reproduction, and altered behaviors, potentially leading to biodiversity loss and disrupted ecological interactions. Biomagnification may further affect higher trophic levels, including humans.

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Maternal offloading of polycyclic aromatic hydrocarbons (PAHs) poses a significant exposure route for developing embryos, with implications for subsequent generations. Despite known developmental effects regarding fish physiology and behavior, maternal PAH transfer assessments in elasmobranchii are still lacking. This study investigated PAH contamination and maternal transfer in one female Lesser Numbfish (Narcine brasiliensis) electric ray and seven embryos for the first time.

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The potential negative impacts of Technology-Critical Elements (TCEs) on the environment and wildlife, despite increasingly recognized, remain largely overlooked. In this sense, this study aimed to investigate the concentrations of several TCEs, including rubidium (Rb), titanium (Ti) and various Rare Earth Elements (REEs), in different tissues of tiger sharks. Sharks incidentally caught by artisanal fleets in southern Brazil were opportunistically sampled and liver, gills, kidneys, heart, muscle, eyes, brain, skin, and teeth were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS).

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Cocaine (COC) and benzoylecgonine (BE), the main COC metabolite, have been detected in aquatic ecosystems. Studies focusing on wild fish are, however, very limited, and no reports concerning elasmobranchs are available. This study investigated COC and BE levels in Brazilian Sharpnose sharks (Rhizoprionodon lalandii) (n = 13) using LC-MS/MS.

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Pakistan, a country with limited water resources and highly vulnerable to the adverse effects of climate change, faces numerous challenges in managing its water supply. In this sense, this study assessed potentially toxic elements (PTEs) in the surface water and sediments of Pakistan's Indus River and its tributaries. Key water quality parameters such as pH, electrical conductivity (EC), and total dissolved solids (TDS) were determined, with respective average values of 7.

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Plastic pollution in aquatic ecosystems is increasing and plastic particles may adsorb and transport a diverse array of contaminants, thereby increasing their bioavailability to biota. This investigation aimed to evaluate the effects of varying polyethylene microplastics (PE MPs) and naphthalene (NAPH) concentrations on the survival and feeding rates of the model organism, Artemia salina, as well as NAPH adsorption to microplastics at different salinity levels (17, 75, 35.5 and 52.

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A mining tailing dam rupture in Brazil in November 2015 released millions of tons of mining waste into the Rio Doce ecosystem, leading to long-term aquatic ecosystem impacts. Although multiple lines of evidence indicate tailings associations with potentially toxic elements in estuarine sediments and biological impact and bioaccumulation pathways in fishes, the extent of contamination in base benthic species is still largely unknown. Moreover, Rare Earth Elements (REE) have not received any attention in this regard.

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Subcellular metal distribution assessments are the most adequate biomonitoring approach to evaluate metal toxicity, instead of total metal assessments This study aimed to assess subcellular metal distributions and associations to the main metal exposure biomarker, metallothionein (MT), in two bromeliad species (Tillandsia usneoides and Tillandsia stricta) exposed established in industrial, urban, and port areas in the metropolitan region of Rio de Janeiro, southeastern Brazil, through an active biomonitoring approach conducted one year. Metals and metalloids in three subcellular fractions (insoluble, thermolabile and thermostable) obtained from the MT purification process were determined by inductively coupled plasma mass spectrometry (ICP-MS). Lower MT concentrations were observed both during the dry sampling periods, associated to the crassulacean acid metabolism (CAM) and during the COVID-19 pandemic, due to reduced urban mobility, decreasing pollutant emissions.

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Aims: Although elasmobranchs are consumed worldwide, bacteriological assessments for this group are still sorely lacking. In this context, this study assessed bacteria of sharks and rays from one of the most important landing ports along the Rio de Janeiro coast.

Methods And Results: Bacteria were isolated from the cloacal swabs of the sampled elasmobranchs.

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A large-scale oil spill along the northeastern Brazilian coast in 2019-2020 severely impacted primary manatee habitats in Brazil. This study aimed to assess metal and metalloid contamination in a dead manatee calf found following this oil spill. Several elements were detected, including chromium, iron, nickel, lead, and vanadium, which are crude oil components, and thallium, a component of dispersants used to degrade and dissipate crude oil.

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Ecotoxicological assessments encompass a broad spectrum of biochemical endpoints and ecological factors, allowing for comprehensive assessments concerning pollutant exposure levels and their effects on both fish populations and surrounding ecosystems. While these evaluations offer invaluable insights into the overall health and dynamics of aquatic environments, they often provide an integrated perspective, making it challenging to pinpoint the precise sources and individual-level responses to environmental contaminants. In contrast, biliary pollutant excretion assessments represent a focused approach aimed at understanding how fish at the individual level respond to environmental stressors.

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Sponges are not routinely employed as metal bioindicators in Brazil. In this sense, this study reports baseline metal and metalloid concentrations, determined by inductively coupled plasma mass spectrometry, for two Demospongiae sponge species, Hymeniacidon heliophila and Desmapsamma anchorata, sampled from two Southeastern Brazil areas. Sponges from Ilha Grande Bay, an Environmental Protection Area, exhibited higher Al, As, Cd, Co, Cr, Fe, and Ni levels compared to Vermelha Beach, a metropolitan area in the Rio de Janeiro city.

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Yeast infections have gained significant attention in the field of marine biology in recent years. Among the broad diversity of marine organisms affected by these infections, elasmobranchs (sharks and rays) have emerged as highly susceptible, due to climate change effects, such as increasing water temperatures and pollution, which can alter the composition and abundance of fungal communities. Additionally, injuries, or compromised immune systems resulting from pollution or disease may increase the likelihood of fungal infections in elasmobranchs.

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Endocrine Disrupting Chemicals (EDCs) encompass a wide variety of substances capable of interfering with the endocrine system, including but not limited to bisphenol A, organochlorines, polybrominated flame retardants, alkylphenols and phthalates. These compounds are widely produced and used in everyday modern life and have increasingly been detected in aquatic matrices worldwide. In this context, this study aimed to carry out a literature review to assess the evolution of EDCs detected in different matrices in the last thirty years.

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Polycyclic aromatic hydrocarbon (PAH) contamination is ubiquitous and comprises a significant worldwide concern in ecological and Public Health frameworks. Many aquatic biota representatives have been reported as contaminated by these toxic compounds, including one of the most threatened vertebrate groups, elasmobranchs (sharks and rays). Although elasmobranchs play important ecological roles and provide significant ecosystem services, they are highly consumed and comprise a cheap source of protein for humans globally.

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Metal contamination poses a significant threat to elasmobranchs, underscoring the need for targeted conservation approaches. The critically endangered Brazilian guitarfish, Pseudobatos horkelii, confronts an array of challenges, notably overexploitation, putting its survival at risk. Our study investigated the potential toxicity arising from arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) contamination across various adult guitarfish tissues from southeastern Brazil.

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The current climate change scenario caused by anthropogenic activities has resulted in novel environmental pressures, increasing the occurrence and severity of fungal infections in the marine environment. Research on fungi in several taxonomic groups is widespread although not the case for elasmobranchs (sharks and rays). In this context, the aim of the present study was to screen the oral fungal microbiota present in artisanally captured , a batoid that, although endangered, is highly fished and consumed worldwide.

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Metal contamination associated with mining activities has been considered one of the main environmental pollution problems in the Amazon region. Understanding the levels of metal contamination from mining activities requires a good understanding of background metal concentrations, which may vary notably according to the geology/lithology characteristics of the region, soil type, and predominant biogeochemical processes. This review assessed 50 papers and reports published between 1989 and 2020 describing environmental concentrations of different metals and metalloids (As, Hg, Mn, Fe, Cd, Cu, Cr, Pb, Ni, and Zn) in water and sediments of mining and non-mining areas in five geographic regions of the Amazon basin.

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Article Synopsis
  • Organochlorine pesticides (OCP) like DDT are persistent environmental pollutants that pose risks to marine life and humans, especially in developing countries where their use continues despite restrictions.
  • This study investigated OCP levels in muscle and liver tissues of various marine species in Southeastern Brazil, finding the highest concentrations of DDE in Franciscana dolphins and generally higher levels in liver than muscle.
  • The research highlighted the need for ongoing monitoring of OCP in the region to protect local dolphin populations and assess potential health risks for coastal human communities.
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