Acute toxicity testing of 6PPD-quinone on the estuarine-dependent sport fish, Sciaenops ocellatus.

Recently, large-scale fish kills in the Pacific Northwest were linked to tire wear particles (TWPs) left on roadways, with the lethality attributed to 6PPD-quinone. which has a median lethal concentration of <1 µg/L for selected salmonids. However, there remains a paucity of 6PPD-quinone toxicity values developed for estuarine fish species, which is particularly significant because estuaries receiving inflows from highly urbanized watersheds are especially vulnerable to TWP contamination. Therefore, the present study aimed to determine the toxicity of 6PPD-quinone to an economically and ecologically important estuarine-dependent fish-red drum (Sciaenops ocellatus). Here, we examined the relative sensitivities of three early life stages within red drum: embryonic, larval, and post-settlement for 24-72 hours, depending on the life stage. Exposure concentrations ranged from 10 µg/L to 500 µg/L. We also assessed the sub-lethal impacts of 6PPD-quinone exposure on development during embryonic and larval stages, including body and organ sizes. Our results indicate that red drum are not acutely sensitive to 6PPD-quinone at each early life stage tested. We also found that yolk-sac larvae did not exhibit sub-lethal morphological impacts in a dose-dependent manner, regardless of exposure during embryonic and larval stages. These data are the first to assess the impacts of 6PPD-quinone on estuarine-dependent non-model fishes.

Comparative Effects of Embryonic Metformin Exposure on Wild and Laboratory-Spawned Fathead Minnow (Pimephales promelas) Populations.

Metformin is routinely detected in aquatic ecosystems because of its widespread use as a treatment for Type 2 diabetes. Laboratory studies have shown that exposure to environmentally relevant concentrations of metformin can alter metabolic pathways and impact the growth of early life stage (ELS) fish; however, it is unknown whether these effects occur in wild populations. Herein, we evaluate whether findings from laboratory studies are representative and describe the relative sensitivities of both populations. Duplicate exposures (0, 5, or 50 µg/L metformin) were conducted using wild- and lab-spawned fathead minnow (Pimephales promelas) embryos. Apart from the water source, exposure conditions remained constant. Wild embryos were exposed to previously dosed lake water to account for changes in bioavailability, while reconstituted freshwater was used for the laboratory study. Developmental metformin exposure differentially impacted the growth and morphology of both cohorts, with energy dyshomeostasis and visual effects indicated. The fitness of wild-spawned larvae was impacted to a greater extent relative to lab-spawned fish. Moreover, baseline data reveal important morphological differences between wild- and lab-spawned ELS fatheads that may diminish representativeness of lab studies. Findings also confirm the bioavailability of metformin in naturally occurring systems and suggest current exposure scenarios may be sufficient to negatively impact developing fish.

Planktonic Fiddler Crab (Uca longisignalis) Are Susceptible to Photoinduced Toxicity Following in ovo Exposure in Oiled Mesocosms.

Benthic organisms may be exposed to polycyclic aromatic hydrocarbons (PAHs) in marine sediments as the result of oil spills. PAH photoinduced toxicity, which has been documented in a wide range of early life stage (ELS) aquatic biota, is a phenomenon by which ultraviolet (UV) radiation potentiates the toxicity of photodynamic PAHs (often leading to mortality). Fiddler crabs (Uca longisignalis) are important ecosystem engineers that influence biogeochemical cycles via burrowing. As gravid females burrow, their eggs may bioaccumulate PAHs from contaminated sediments, leading to in ovo exposure. Consequently, free-swimming larvae exposed to intense UV may be at risk for photoinduced toxicity. In the present study, mature fiddler crabs were bred on oiled sediments contaminated via simulated tidal flux. Gravid females were transferred to clean water after 10 days, and larvae were collected at hatch. While in ovo exposures to oil alone did not affect survival, offspring that were subsequently exposed to full spectrum sunlight in clean water experienced significant mortality that corresponded with in ovo exposures to sediments containing ≥1455 µg/kg tPAH50. Results presented here provide evidence for the potential of photoinduced toxicity to occur in benthic organisms with free-swimming early life stages.

Alterations to the Intestinal Microbiome and Metabolome of Pimephales promelas and Mus musculus Following Exposure to Dietary Methylmercury.

Mercury is a global contaminant, which may be microbially transformed into methylmercury (MeHg), which bioaccumulates. This results in potentially toxic body burdens in high trophic level organisms in aquatic ecosystems and maternal transfer to offspring. We previously demonstrated effects on developing fish including hyperactivity, altered time-to-hatch, reduced survival, and dysregulation of the dopaminergic system. A link between gut microbiota and central nervous system function in teleosts has been established with implications for behavior. We sequenced gut microbiomes of fathead minnows exposed to dietary MeHg to determine microbiome effects. Dietary exposures were repeated with adult CD-1 mice. Metabolomics was used to screen for metabolome changes in mouse brain and larval fish, and results indicate effects on lipid metabolism and neurotransmission, supported by microbiome data. Findings suggest environmentally relevant exposure scenarios may cause xenobiotic-mediated dysbiosis of the gut microbiome, contributing to neurotoxicity. Furthermore, small-bodied teleosts may be a useful model species for studying certain types of neurodegenerative diseases, in lieu of higher vertebrates.

Effects of metformin on wild fathead minnows (Pimephales promelas) using in-lake mesocosms in a boreal lake ecosystem.

Due to its widespread use for the treatment of Type-2 diabetes, metformin is routinely detected in surface waters globally. Laboratory studies have shown that environmentally relevant concentrations of metformin can adversely affect the health of adult fish, with effects observed more frequently in males. However, the potential risk to wild fish populations has yet to be fully elucidated and remains a topic of debate. To explore whether environmentally relevant metformin exposure poses a risk to wild fish populations, the present study exposed wild fathead minnows (Pimephales promelas) to 5 or 50 µg/L metformin via 2 m diameter in-lake mesocosms deployed in a natural boreal lake in Northern Ontario at the International Institute for Sustainable Development - Experimental Lakes Area (IISD-ELA). Environmental monitoring was performed at regular intervals for 8-weeks, with fish length, weight (body, liver and gonad), condition factor, gonadosomatic index, liver-somatic index, body composition (water and biomolecules) and hematocrit levels evaluated at test termination. Metabolic endpoints were also evaluated using liver, brain and muscle tissue, and gonads were evaluated histologically. Results indicate that current environmental exposure scenarios may be sufficient to adversely impact the health of wild fish populations. Adult male fish exposed to metformin had significantly reduced whole body weight and condition factor and several male fish from the high-dose metformin had oocytes in their testes. Metformin-exposed fish had altered moisture and lipid (decrease) content in their tissues. Further, brain (increase) and liver (decrease) glycogen were altered in fish exposed to high-dose metformin. To our knowledge, this study constitutes the first effort to understand metformin's effects on a wild small-bodied fish population under environmentally relevant field exposure conditions.

Injuries following accidents with electric scooters.

INTRODUCTION: Since the introduction of electric scooter (e-scooter) rental services in Denmark in January 2019, injuries following accidents involving e-scooters have increased. Internationally, a few studies have been published examining patient and injury characteristics following accidents involving e-scooters. However, data are limited. The purpose of this study was to describe the injuries, treatment and hospital course following accidents involving e-scooters. METHODS: Prospective collection of data on all persons involved in accidents related to e-scooters who were examined and treated at the Emergency Department of Bispebjerg and Frederiksberg, Denmark, during the period from 30 June 2019 to 30 September 2019. RESULTS: A total of 49 patients, 37 (75.5%) male, 46 riders and three non-riders, with a median age of 26 years (range: 8-56 years) were admitted to the emergency department. Common injuries were head injuries (46.9%) and fractures (26.5%). Most patients (79.6%) were discharged to their home from the emergency department after treatment without further hospital follow-up. CONCLUSIONS: The majority of persons involved in e-scooter accidents are young men. Our results revealed a high frequency of head injuries and fractures. Most patients were discharged to their home after treatment in the emergency department. FUNDING: none. TRIAL REGISTRATION: The study was approved as a quality control project by the Head of the Department of Emergency Medicine and the Head of the Hospital Administration.

An 'omics approach to investigate the growth effects of environmentally relevant concentrations of guanylurea exposure on Japanese medaka (Oryzias latipes).

Metformin is a widely prescribed pharmaceutical used in the treatment of numerous human health disorders, including Type 2 Diabetes, and as a results of its widespread use, metformin is thought to be the most prevalent pharmaceutical in the aquatic environment by weight. The removal of metformin during the water treatment process is directly related to the formation of its primary degradation product, guanylurea, generally present at higher concentrations in surface waters relative to metformin. Growth effects observed in 28-day early life stage (ELS) Japanese medaka exposed to guanylurea were found to be similar to growth effects in 28-day ELS medaka exposed to metformin; however, effect concentrations were orders of magnitude below those of metformin. The present study uses a multi-omics approach to investigate potential mechanisms by which low-level, 1 ng · L-1 nominal, guanylurea exposure may lead to altered growth in 28-day post hatch medaka via shotgun metabolomics and proteomics and qPCR. Specifically, analyses show 6 altered metabolites, 66 altered proteins and 2 altered genes. Collectively, metabolomics, proteomics, and gene expression data (using qPCR) indicate that developmental exposure to guanylurea exposure alters a number of important pathways related to the overall health of ELS fish, including biomolecule metabolism, cellular energetics, nervous system function/development, cellular communication and structure, and detoxification of reactive oxygen species, among others. To our knowledge, this is the first study to both report the molecular level effects of guanylurea on non-target aquatic organisms, and to relate molecular-level changes to whole organism effects.