Emerging investigator series: nontargeted screening of aryl hydrocarbon receptor agonists in endangered beluga whales from the St. Lawrence Estuary: beyond legacy contaminants.

The elevated concentrations of organohalogen contaminants in the endangered St. Lawrence Estuary (SLE) belugas have prompted the hypothesis that aryl hydrocarbon receptor (AhR) activity may be a contributor towards their potential adverse effects. While indirect associations between AhR and contaminant levels have been reported in SLE beluga tissues, AhR activity was never directly measured.

Variations in thyroid hormone levels in endangered St. Lawrence Estuary belugas: Potential linkage with stress and organohalogen contaminant exposure.

The St. Lawrence Estuary (SLE) beluga (Delphinapterus leucas) population is highly exposed to an array of contaminants that were identified as one of the causes to the non-recovery of this endangered and declining population. In the last decade, an increasing number of parturition-associated complications and calf mortality has been reported in this population.

Impact of landfill characteristics on the atmospheric exposure to halogenated flame retardants in gulls.

Large amounts of consumer products containing halogenated flame retardants (HFRs) are disposed of annually in landfills, which may lead to significant releases of these semi-volatile contaminants into the environment. During their foraging activities in landfills, gulls can be exposed to elevated levels of HFRs in air. Ring-billed gulls (Larus delawarensis) breeding in the densely populated Montreal area (QC, Canada) are significantly exposed to air levels of polybrominated diphenyl ethers (PBDEs) in or in the vicinity of landfills.

Halogenated flame retardant exposure pathways in urban-adapted gulls: Are atmospheric routes underestimated?

Urban-adapted gulls can be exposed to flame retardants while foraging in landfills where elevated concentrations of polybrominated diphenyl ethers (PBDEs) and other halogenated flame retardants (HFRs) have frequently been measured in air. However, the contribution of atmospheric exposure has largely been overlooked compared to dietary exposure in birds and other wildlife. The overall objective of this study was to investigate the contribution of atmospheric exposure pathways relative to diet for PBDEs and other HFRs in ring-billed gulls (Larus delawarensis) nesting in the densely populated Montreal area (QC, Canada).

Biotransformation of Dec-604 and potential effect on thyroid deiodinase activity in highly flame retardant-exposed gulls.

Several halogenated flame retardants (HFRs) have been identified as thyroid disruptors in birds including the polybrominated diphenyl ether (PBDE) mixtures, which have been replaced with other HFRs such as Dechlorane-604 (Dec-604). Dec-604 Component B (Dec-604 CB), a putative debrominated product of Dec-604, has been frequently reported in urban-adapted ring-billed gulls (Larus delawarensis) breeding in the Montreal area (QC, Canada). The metabolic pathways of Dec-604 are yet to be characterized, although the occurrence of Dec-604 CB in gulls may suggest that enzyme-mediated dehalogenation may occur, potentially involving the thyroid deiodinases.

Occurrence and temporal trends of industrial antioxidants and UV absorbents in the endangered St. Lawrence Estuary beluga whale (Delphinapterus leucas).

Elevated contaminant exposure has been identified as a stressor that has negative impacts on the health and recovery of the endangered St. Lawrence Estuary (SLE) beluga (Delphinapterus leucas) population. However, the accumulation of many groups of contaminants of emerging concern is still unknown in the SLE beluga.

Triclosan is the Predominant Antibacterial Compound in Ontario Sewage Sludge.

Sewage treatment plants (STPs) accumulate both antibiotic and nonantibiotic antimicrobial compounds that can select for antibiotic resistant bacteria. Herein, we aimed to identify the predominant antibacterial compounds impacting from Ontario sewage sludge consisting of thousands of unknown compounds. Among the 10 extracted sludge samples, 6 extracts exerted significant growth inhibition effects in .

Flame retardants and their associations with thyroid hormone-related variables in northern fulmars from the Faroe Islands.

Flame retardants (FRs) are widely reported in tissues of seabirds including birds sampled from remote areas. There is evidence that FRs can disrupt the hypothalamic-pituitary-thyroid (HPT) axis in seabirds, although information is limited on thyroid-related mechanisms and effects. This study investigated the associations between concentrations of polybrominated diphenyl ethers (PBDEs) and other FRs, and changes in the HPT axis in northern fulmars (Fulmarus glacialis) from the Faroe Islands (North Atlantic).

Disruption by stealth - Interference of endocrine disrupting chemicals on hormonal crosstalk with thyroid axis function in humans and other animals.

Thyroid hormones (THs) are important regulators of growth, development, and homeostasis of all vertebrates. There are many environmental contaminants that are known to disrupt TH action, yet their mechanisms are only partially understood. While the effects of Endocrine Disrupting Chemicals (EDCs) are mostly studied as "hormone system silos", the present critical review highlights the complexity of EDCs interfering with TH function through their interactions with other hormonal axes involved in reproduction, stress, and energy metabolism.

Time-dependent biological responses of juvenile yellow perch (Perca flavescens) exposed in situ to a major urban effluent.

Municipal wastewater treatment plant (WWTP) effluents are significant sources of organic and inorganic pollutants to aquatic ecosystems. Several studies have shown that the health of aquatic organisms can be adversely impacted following exposure to these complex chemical mixtures. The objective of this study was to examine the effects of in situ exposure in the St.

Spatial and temporal variations of halogenated flame retardants and organophosphate esters in landfill air: Potential linkages with gull exposure.

Landfills represent important sources of local emissions of organic contaminants, including halogenated (HFR) and organophosphate ester (OPE) flame retardants used in a large variety of consumer products. Gulls foraging in landfills may be exposed to elevated atmospheric concentrations of HFRs and OPEs that may vary spatially and temporally within a landfill site, thus modulating their exposure. The objective of the present study was to investigate the spatial and temporal variability of HFR and OPE concentrations in air samples collected from a major landfill in the Montreal area (QC, Canada) that is frequently visited by gulls for foraging.

Suspect and Nontarget Screening Revealed Class-Specific Temporal Trends (2000-2017) of Poly- and Perfluoroalkyl Substances in St. Lawrence Beluga Whales.

The global use of >3000 per- and polyfluoroalkyl substances (PFASs) has given rise to chemical regulatory action. However, limited information exists regarding current and historical emissions for the majority of PFASs under currently implemented regulations. This study employed suspect and nontarget screening to examine the temporal trends of legacy and unregulated PFASs in liver of the endangered beluga whale () population from the St.

Gulls foraging in landfills: Does atmospheric exposure to halogenated flame retardants result in bioaccumulation?

Several bird species have adapted to foraging in landfills, although these sites are known to represent significant sources of emissions of toxic semi-volatile chemicals including the halogenated flame retardants (HFRs) (e.g., polybrominated diphenyl ethers (PBDEs) and emerging compounds).

Lipid metabolites as indicators of body condition in highly contaminant-exposed belugas from the endangered St. Lawrence Estuary population (Canada).

The endangered St. Lawrence Estuary (SLE) beluga population is declining and has shown no sign of recovery over the past decades despite several protective measures. Changes in the availability of food resources and exposure to organohalogen contaminants have been suggested as potential factors limiting the recovery of this population.

Bidirectional transfer of halogenated flame retardants between the gastrointestinal tract and ingested plastics in urban-adapted ring-billed gulls.

The hypothesis that plastics can transfer chemical pollutants to organisms after ingestion has been supported by several lab and field studies. However, models indicate that this transfer could be bidirectional and that whether chemicals move from plastics to the animal or vice versa, depends on several factors, including the relative concentrations of chemicals in both the animal and the plastics ingested. To explore this phenomenon in the field, we examined the relative concentrations of several halogenated flame retardants (HFRs) in a population of urban-dwelling ring-billed gulls (Larus delawarensis) and the plastics in their gastrointestinal (GI) tracts.

Trophic transfer of polybrominated diphenyl ethers in a recently modified freshwater food web from the St. Lawrence River, Canada.

Introduction of invasive species can have a profound impact on food web structure and therefore on trophic transfer of contaminants. In the St. Lawrence River (Canada), 20 years after its first detection in the system, invasive round goby (Neogobius melanostomus) has become the main prey for several piscivorous species.

An investigation of physiological effects of the Deepwater Horizon oil spill on a long-distance migratory seabird, the northern gannet.

Exposure to oil can have long-term impacts on migratory birds. Following the 2010 Deepwater Horizon blowout in the Gulf of Mexico (GOM), we investigated potential impacts of oil exposure on a population of northern gannets (Morus bassanus) that breed on Bonaventure Island (Québec, Canada) and winter in GOM and along the U.S.

Metabolomic profiles of the endangered St. Lawrence Estuary beluga population and associations with organohalogen contaminants.

The endangered beluga (Delphinapterus leucas) population residing in the St. Lawrence Estuary (SLE; Eastern Canada) is declining. The elevated tissue concentrations of a wide range of organohalogen contaminants might play a role in the non-recovery of this whale population.

Environmental exposure of northern pike to a primary wastewater effluent: Impact on the lipidomic profile and lipid metabolism.

Lipids play important roles in growth, reproduction, locomotion, and migration of fish. Municipal effluents, which are complex mixtures of biological and chemical compounds including flame retardants, have been shown to alter lipid metabletabolism in environmentally and experimentally exposed fish. Down-regulation of several genes coding for fatty acid metabolism enzymes has previously been reported in male northern pike (Esox lucius) collected in the St.

Influence of overwinter distribution on exposure to persistent organic pollutants (POPs) in seabirds, ancient murrelets (Synthliboramphus antiquus), breeding on the Pacific coast of Canada.

Assessing the fate of both legacy and newer persistent organic pollutants (POPs) is an ongoing challenge. Top predators, including seabirds, are effective monitors of POPs because they forage over a range of marine habitats, integrating signals over space and time. However, migration patterns can make unravelling contaminant sources, and potentially assessments of the effectiveness of regulations, challenging if chemicals are acquired at distant sites.

Changes in plasma biochemistry in breeding ring-billed gulls: Effects of anthropogenic habitat use and contaminant exposure.

Gulls (Larids) have become successful at exploiting anthropogenic areas for foraging. However, little is known on the health implications of using anthropogenic habitats and on the associated exposure to environmental contaminants, particularly with respect to plasma biochemistry that is routinely used to diagnose physiological disorders and diseases. The objective of the present study was to investigate the effects of anthropogenic habitat use and exposure to ubiquitous halogenated flame retardants (HFRs) on plasma biochemistry of urban-breeding ring-billed gulls (Larus delawarensis) from one of the largest colonies in North America.

Landfills represent significant atmospheric sources of exposure to halogenated flame retardants for urban-adapted gulls.

Halogenated flame retardants (HFRs) are contaminants that are abundantly emitted from waste management facilities (WMFs) and that became ubiquitous in air of urbanized regions. Urban birds including gulls have adapted to exploiting human food resources (refuse) in WMFs, and have thus experienced population explosions worldwide. However, foraging in WMFs for birds may result in exposure to HFRs that have been shown to be toxic for animals.

Associations between organohalogen exposure and thyroid- and steroid-related gene responses in St. Lawrence Estuary belugas and minke whales.

Elevated concentrations of persistent organic pollutants (POPs) and emerging halogenated flame retardants (HFRs) have been reported in tissues of the endangered St. Lawrence Estuary (Canada) beluga population as well as in minke whales visiting that same feeding area. This study examined the linkages between blubber concentrations of POPs and emerging HFRs, and transcription in skin of genes involved in the regulation of thyroid and steroid axes in belugas and minke whales from the St.

Suspect screening of plastic-related chemicals in northern pike (Esox lucius) from the St. Lawrence River, Canada.

Environmental contaminant monitoring traditionally relies on targeted analysis, and very few tools are currently available to monitor "unexpected" or "unknown" compounds. In the present study, a non-targeted workflow (suspect screening) was developed to investigate plastic-related chemicals and other environmental contaminants in a top predator freshwater fish species, the northern pike, from the St. Lawrence River, Canada.

Habitat use strategy influences the tissue signature of trace elements including rare earth elements in an urban-adapted omnivorous bird.

Concentrations of trace elements vary naturally between geological environments and as a result of emissions from anthropogenic activities. Habitat use strategy is an important determinant of trace element concentrations in tissues and eggs of wild birds. However, a scarcity of studies have documented the relationships between individual bird movements related to foraging activities and exposure to contaminants including trace elements.