Enhanced uptake of perfluorooctanoic acid by polystyrene nanoparticles in Pacific oyster (Magallana gigas).

The effects of plastic pollution on marine organisms is of growing concern. The hydrophobic surface of plastics adsorbs organic contaminants and can alter the rate of chemical uptake in fishes. Per-fluorinated organic chemicals such as Perfluorooctanoic acid (PFOA) are highly hydrophobic toxic chemicals that adsorb to hydrophobic surfaces.

Identification and hazard prioritization of hydrophobic organic chemicals in flowback and produced water particles: Implications for water management.

Hydraulic fracturing flowback and produced water (HF-FPW) has raised significant concerns owing to its potential impact on aquatic organisms and human health. Understanding the chemical composition of HF-FPW is crucial for developing appropriate management and remediation strategies. Herein, we performed nontarget screening on hydrophobic organic chemicals in the particulate phase of FPW (P-FPW) using gas chromatography-Orbitrap mass spectrometry coupled with cheminformatic analysis.

Impacts of UV light on the effects of either conventional or nano-enabled azoxystrobin on Daphnia magna.

Agri-chemicals such as fungicides are applied in natural settings and hence are exposed to the environment's ultraviolet (UV) light. Recently, many fungicides in commerce are being modified as nano-enabled formulations to increase agricultural productivity and reduce potential off-target effects. The present study investigated the impacts of sunlight-grade UV emission on the effects of either conventional or nano-enabled azoxystrobin (Az or nAz, respectively), a commonly applied agricultural fungicide, on Daphnia magna.

Cellular mechanisms of ion and acid-base regulation in teleost gill ionocytes.

The mechanism(s) of sodium, chloride and pH regulation in teleost fishes has been the subject of intense interest for researchers over the past 100 years. The primary organ responsible for ionoregulatory homeostasis is the gill, and more specifically, gill ionocytes. Building on the theoretical and experimental research of the past, recent advances in molecular and cellular techniques in the past two decades have allowed for substantial advances in our understanding of mechanisms involved.

Evidence for transporter-mediated uptake of environmental L-glutamate in a freshwater sponge, Ephydatia muelleri.

The freshwater sponge, Ephydatia muelleri, lacks a nervous or endocrine system and yet it exhibits a coordinated whole-body action known as a "sneeze" that can be triggered by exposure to L-glutamate. It is not known how L-glutamate is obtained by E. muelleri in sufficient quantities (i.

Mechanistic characterization of waterborne selenite uptake in the water flea, , indicates water chemistry affects toxicity in coal mine-impacted waters.

Concentrations of selenium that exceed regulatory guidelines have been associated with coal mining activities and have been linked to detrimental effects on aquatic ecosystems and the organisms therein. Although the major route of selenium uptake in macroinvertebrates is via the diet, the uptake of waterborne selenite (HSeO), the prominent form at circumneutral pH, can be an important contributor to selenium body burden and thus selenium toxicity. In the current study, radiolabelled selenite (Se) was used to characterize the mechanism of selenite uptake in the water flea, .

Effects of Acute and Subchronic Waterborne Thallium Exposure on Ionoregulatory Enzyme Activity and Oxidative Stress in Rainbow Trout (Oncorhynchus mykiss).

The mechanisms of acute (96-hour) and subchronic (28-day) toxicity of the waterborne trace metal thallium (Tl) to rainbow trout (Oncorhynchus mykiss) were investigated. Specifically, effects on branchial and renal ionoregulatory enzymes (sodium/potassium adenosine triphosphatase [ATPase; NKA] and proton ATPase) and hepatic oxidative stress endpoints (protein carbonylation, glutathione content, and activities of catalase and glutathione peroxidase) were examined. Fish (19-55 g) were acutely exposed to 0 (control), 0.

Mechanistic examination of thallium and potassium interactions in Daphnia magna.

The trace element thallium (Tl) exerts its toxic effects, at least in part, through its mimicry of potassium (K) and subsequent impairment of K homeostasis. However, the specific nature of this effect remains poorly understood, especially in aquatic biota that are threatened by elevated concentrations of Tl associated with mining and refining effluents. In this study experiments were conducted to mechanistically examine the relationship between Tl and K in terms of uptake and toxicity in the regulatory model species Daphnia magna.

Accumulation of Thallium in Rainbow Trout (Oncorhynchus mykiss) Following Acute and Subchronic Waterborne Exposure.

The accumulation and tissue distribution of toxicants in aquatic biota can be determinative of their toxic impact to both exposed organisms and their potential human consumers. In the present study, accumulation of the trace metal thallium (Tl) in gill, muscle, plasma, and otoliths of rainbow trout (Oncorhynchus mykiss) following acute (96-h) and subchronic (28-day) waterborne exposures was investigated. Owing to known interactions between Tl and potassium ions (K ), plasma and muscle K concentrations were also determined.

The Acute and Chronic Effects of a Sediment-Bound Synthetic Musk, Galaxolide, on Hyalella azteca, Chironomus dilutus, and Lumbriculus variegatus.

Galaxolide is one of the most frequently used synthetic polycyclic musks on the market and is commonly detected in aquatic waterways. Previous studies have mainly evaluated the toxicity of this emerging contaminant using water-only exposures; however, its high Log K (5.9) suggests that this compound is likely to partition to sediments.

Sub-chronic exposure to waterborne extracellular microcystin-LR impairs calcium homeostasis in rainbow trout.

Fish mortality is associated with harmful algal blooms, although whether toxicity is related directly to the presence of cyanotoxins or the prevailing water chemistry remains unclear. Similarly, while planktivorous fish may be exposed to toxin through the diet, the hazard posed by waterborne extracellular toxin to carnivorous fish is less well understood. In this study rainbow trout (Oncorhynchus mykiss) were exposed for up to 28 d to waterborne microcystin-LR at nominal concentrations of 1.

Latent impacts on juvenile rainbow trout (Oncorhynchus mykiss) cardio-respiratory function and swimming performance following embryonic exposures to hydraulic fracturing flowback and produced water.

Technologies associated with hydraulic fracturing continue to be prevalent in many regions worldwide. As a result, the production of flowback and produced water (FPW) - a wastewater generated once pressure is released from subterranean wellbores - continues to rise in regions experiencing fracturing activities, while waste management strategies attempt to mitigate compounding burdens of increased FPW production. The heightened production of FPW increases the potential for release to the environment.

Factors Affecting the Binding of Diltiazem to Rainbow Trout Plasma: Implications for the Risk Assessment of Pharmaceuticals in Aquatic Systems.

The accumulation of organic toxicants in fish plasma, and how they partition between the bound and unbound fraction once absorbed, are important metrics in models that seek to predict the risk of such contaminants in aquatic settings. Rapid equilibrium dialysis of diltiazem, an ionizable weak base and important human pharmaceutical contaminant of freshwaters, was conducted with rainbow trout (Oncorhynchus mykiss) plasma. The effect of fed state, fish sex, fish strain/size, and dialysis buffer pH on the binding of radiolabeled diltiazem (9 ng ml ) was assessed.

The roles of plasma accessible and cytosolic carbonic anhydrases in bicarbonate (HCO) excretion in Pacific hagfish (Eptatretus stoutii).

Pacific hagfish (Eptatretus stoutii) are marine scavengers and feed on decaying animal carrion by burrowing their bodies inside rotten carcasses where they are exposed to several threatening environmental stressors, including hypercapnia (high partial pressures of CO). Hagfish possess a remarkable capacity to tolerate hypercapnia, and their ability to recover from acid-base disturbances is well known. To deal with the metabolic acidosis resulting from exposure to high CO, hagfish can mount a rapid elevation of plasma HCO concentration (hypercarbia).

Freshwater Sediment Toxicity Evaluation from Meso-Scale Spill Tests of Diluted Bitumen and Conventional Crude.

Oil and gas development and transportation in many areas of the world, such as the oil sands region of Alberta, Canada, are heavily monitored to minimize the environmental impacts of development and the risk of oil spills. However, oil spills to aquatic environments still occur. Although the science of oil spills has received considerable attention of late, uncertainty still remains in evaluating the fate and transport of oil spills as well as the effects of those spills on aquatic biota.

Embryonic cardio-respiratory impairments in rainbow trout (Oncorhynchus mykiss) following exposure to hydraulic fracturing flowback and produced water.

During hydraulic fracturing, wastewaters - termed flowback and produced water (FPW) - are created as a by-product during hydrocarbon extraction. Given the large volumes of FPW that a single well can produce, and the history of FPW release to surface water bodies, it is imperative to understand the hazards that hydraulic fracturing and FPW pose to aquatic biota. Using rainbow trout embryos as model organisms, we investigated impacts to cardio-respiratory system development and function following acute (48 h) and sub-chronic (28-day) FPW exposure by examining occurrences of developmental deformities, rates of embryonic respiration (MO), and changes in expression of critical cardiac-specific genes.

A numerical modeling framework for simulating the key in-stream fate processes of PAH decay in Muskeg River Watershed, Alberta, Canada.

Most previous water quality studies oversimplified in-stream processes for modeling the fate and transport of critical organic contaminants, such as Polycyclic Aromatic Hydrocarbons (PAHs). Taking four selected PAHs as representative organic contaminants, we developed a numerical modeling framework using a Water Quality Analysis Simulation Program 8 (WASP8) and a well-established watershed model, i.e.

Nanotechnology in agriculture: Comparison of the toxicity between conventional and nano-based agrochemicals on non-target aquatic species.

Increased crop production is necessary to keep up with rising food demand. However, conventional agricultural practices and agrochemicals are unable to sustain further increases without serious risk of adverse environmental consequences. The implementation of nanotechnology in agriculture practices has been increasing in recent years and has shown tremendous potential to boost crop production.

Effect of thallium on phototactic behaviour in Daphnia magna.

Thallium (Tl) is a trace metal enriched in wastewaters associated with mining and smelting of base metals. The toxicity of Tl to aquatic biota is poorly understood, particularly with respect to its sublethal effects. In this study, phototactic behavioural responses of naïve (i.

Dining on the dead in the deep: Active NH excretion via Na /H (NH ) exchange in the highly ammonia tolerant Pacific hagfish, Eptatretus stoutii.

Aim: Pacific hagfish are exceptionally tolerant to high environmental ammonia (HEA). Here, we elucidated a cellular mechanism that enables hagfish to actively excrete ammonia against steep ammonia gradients expected to be found inside a decomposing whale carcass.

Methods: Hagfish were exposed to varying concentrations of HEA in the presence or absence of environmental Na , while plasma ammonia levels were tracked.

Hypoxemia as the mechanism of acute cationic polymer toxicity in rainbow trout and prevention of toxicity using an anionic neutralizing polymer.

Industrial operations such as surface mining, road building, and aggregate washing result in high concentrations of suspended particles (Total Suspended Solids; TSS) in surface waters which must be treated prior to discharge into fish-bearing waters. A common industrial practice is to add flocculants to improve the efficacy and speed of TSS sedimentation. A significant environmental issue even small amounts of uncomplexed cationic polymer coagulant/flocculant remaining in treated water is highly toxic to fish at very low concentrations (LC ∼ 0.

Absence of some cytochrome P450 (CYP) and hydroxysteroid dehydrogenase (HSD) enzymes in hagfishes.

Corticosteroids are synthesized from cholesterol by steroidogenic enzyme catalysts belonging to two main families: the cytochrome p450s (CYPs) and hydroxysteroid dehydrogenases (HSDs). The action of these steroidogenic enzymes allows the genesis of the terminal active corticosteroids 11-deoxycortisol (S), 1ɑ-hydroxycorticosterone (1α-OH-B), or cortisol in different fish species. However, for Cyclostomes like hagfishes, the terminal corticosteroid is still undefined.

Complex impacts of hydraulic fracturing return fluids on soil microbial community respiration, structure and functional potentials.

The consequences of soils exposed to hydraulic fracturing (HF) return fluid, often collectively termed flowback and produced water (FPW), are poorly understood, even though soils are a common receptor of FPW spills. Here, we investigate the impacts on soil microbiota exposed to FPW collected from the Montney Formation of western Canada. We measured soil respiration, microbial community structure and functional potentials under FPW exposure across a range of concentrations, exposure time and soil types (luvisol and chernozem).

Acute waterborne strontium exposure to rainbow trout: Tissue accumulation, ionoregulatory effects, and the modifying influence of waterborne calcium.

Flowback and produced water (FPW) is an end-product of the hydraulic fracturing method of oil and gas extraction that is highly enriched in alkaline earth metals such as strontium (Sr). While Sr concentrations in FPW can exceed toxic thresholds for fish, the accompanying high concentrations of calcium (Ca) in FPW may ameliorate any toxicity. In this study, Sr bioaccumulation and molecular, biochemical, and physiological changes in ionoregulatory endpoints were investigated in rainbow trout (Oncorhynchus mykiss).