Considerations and data update for the inference of environmental quality standards for two avermectins widely used in salmon aquaculture.

We have updated and reviewed toxicity data for Emamectin benzoate (EMB) and Ivermectin (IVER), two in-feed drugs used to treat sea lice in farmed Atlantic salmon, and inferred new Environmental Quality Standards (EQS) using a deterministic approach or Species Sensitivity Distributions (SSDs) based on available data. We used a SSD model averaging approach and inferred a water acute EQS value of 24.9 ng/L (SSD) for EMB, while previously established chronic water EQS of 0.

Changes in Temperature Alter the Toxicity of Polycyclic Aromatic Compounds to American Lobster (Homarus americanus) Larvae.

Polycyclic aromatic compounds (PACs) present in the water column are considered to be one of the primary contaminant groups contributing to the toxicity of a crude oil spill. Because crude oil is a complex mixture composed of thousands of different compounds, oil spill models rely on quantitative structure-activity relationships like the target lipid model to predict the effects of crude oil exposure on aquatic life. These models rely on input provided by single species toxicity studies, which remain insufficient.

Calibration of an acute toxicity model for the marine crustacean, Artemia franciscana, nauplii to support oil spill effect assessments.

Oil spill risk and impact assessments rely on time-dependent toxicity models to predict the hazard of the constituents that comprise crude oils and petroleum substances. Dissolved aromatic compounds (ACs) are recognized as a primary driver of aquatic toxicity in surface spill exposure scenarios. However, limited time-dependent toxicity data are available for different classes of ACs to calibrate such models.

Species sensitivity distributions for two widely used anti-sea lice chemotherapeutants in the salmon aquaculture industry.

The main objective of the present study is to construct acute aquatic species sensitivity distributions (SSD) and generate proposed HC values (i.e. the hazardous concentration for which 5 % of species are affected or potentially affected) for two aquaculture anti-sea lice bath pesticides, azamethiphos, and hydrogen peroxide.

Prioritization of Pesticides for Assessment of Risk to Aquatic Ecosystems in Canada and Identification of Knowledge Gaps.

Pesticides can enter aquatic environments via direct application, via overspray or drift during application, or by runoff or leaching from fields during rain events, where they can have unintended effects on non-target aquatic biota. As such, Fisheries and Oceans Canada identified a need to prioritize current-use pesticides based on potential risks towards fish, their prey species, and habitats in Canada. A literature review was conducted to: (1) Identify current-use pesticides of concern for Canadian marine and freshwater environments based on use and environmental presence in Canada, (2) Outline current knowledge on the biological effects of the pesticides of concern, and (3) Identify general data gaps specific to biological effects of pesticides on aquatic species.

Assessing the Toxicity of Individual Aromatic Compounds and Mixtures to American Lobster (Homarus americanus) Larvae Using a Passive Dosing System.

Aquatic exposures to aromatic compounds (ACs) may be important contributors to biological effects of oil spills. The present study examined the acute toxicity of 11 ACs and 3 binary AC mixtures on stage 1 American lobster larvae using a passive dosing test design. The ACs investigated covered a range of classes and log octanol-water partition coefficient values (K ; 2.

A review of 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane in the environment and assessment of its persistence, bioaccumulation and toxicity.

Following the ban of many historically-used flame retardants (FRs), numerous replacement chemicals have been produced and used in products, with some being identified as environmental contaminants. One of these replacement flame retardants is 1,2-dibromo-4-(1,2-dibromoethyl)-cyclohexane (DBE-DBCH; formerly abbreviated as TBECH), which to date has not been identified for risk assessment and potential regulation. DBE-DBCH technical mixtures consist largely of α- and β-diastereomers with trace amounts of γ- and δ-DBE-DBCH.

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.

Uptake, Deposition, and Metabolism of Triphenyl Phosphate in Embryonated Eggs and Chicks of Japanese Quail (Coturnix japonica).

The toxicokinetics of triphenyl phosphate (TPHP) in vivo including the uptake, deposition, and biotransformation into the metabolite diphenyl phosphate (DPHP) is presently reported in embryonated eggs and chicks of Japanese quail. Quail were dosed with TPHP at 3 concentrations by air cell egg injection on embryonic day 0, followed by daily oral dosing after chicks hatched (5 d). Vehicle-only exposed controls were also used.

Is the current-use flame retardant, DBE-DBCH, a potential obesogen? Effects on body mass, fat content and associated behaviors in American kestrels.

The current-use brominated flame retardant, 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (DBE-DBCH), is capable of perturbing sex steroid and thyroid hormone pathways in vitro and in vivo. Chemicals with this capability may also disrupt metabolic processes and are candidate obesogens, but this potential has not yet been determined for DBE-DBCH. Our objective was to examine gross biomarkers of metabolic disruption in captive American kestrels.

Changes in thyroid function of nestling tree swallows (Tachycineta bicolor) in relation to polycyclic aromatic compounds and other environmental stressors in the Athabasca Oil Sands Region.

In the Canadian Athabasca Oil Sands Region (AOSR), nestling tree swallows (Tachycineta bicolor) raised near mining-related activities accumulated greater concentrations of polycyclic aromatic compounds (PACs) that contributed to their poorer condition, growth, and reproductive success. Here, we report changes in thyroid function of the same 14 day old (do) nestlings (N ≤ 68) at these mining-related sites (OS1, OS2) compared to reference nestlings (REF1), and in relation to multiple environmental stressors that influence avian thyroid function. Thyroid function was compromised for OS1 nestlings but generally comparable between OS2 and REF1 chicks.

Reproductive and developmental changes in tree swallows (Tachycineta bicolor) are influenced by multiple stressors, including polycyclic aromatic compounds, in the Athabasca Oil Sands.

Mining in the Athabasca Oil Sands Region (AOSR) has contributed extensively to increased exposure of wildlife to naturally occurring polycyclic aromatic compounds (PACs), yet little is known about the toxicity of PACs to wildlife in this region. We identified reproductive and developmental changes in tree swallows (Tachycineta bicolor) breeding in close proximity to mining-related activities in the AOSR, and determined these changes in relation to the birds' exposure and accumulation of 41 PACs (parent-, alkylated-PAHs), dibenzothiophenes (DBTs; previously published), diet (carbon (δC), nitrogen (δN)), volatile organic compounds, and weather variables. Tree swallow pairs (N = 43) were compared among mining-related (OS1, OS2) and reference (REF1, REF2) sites.

Elevated exposure, uptake and accumulation of polycyclic aromatic hydrocarbons by nestling tree swallows (Tachycineta bicolor) through multiple exposure routes in active mining-related areas of the Athabasca oil sands region.

In the Athabasca Oil Sands (OS) Region, the exposure (by air, water, diet), uptake and deposition of polycyclic aromatic compounds (PACs), including parent and alkylated hydrocarbons (PAHs) and dibenzothiophenes (DBTs), was assessed in nestling tree swallows (Tachycineta bicolor) at mining-related (OS1, OS2) and reference (REF) sites. The OS sites did not receive oil-sands processed waters (OSPW) and were ≥60km from the reference sites. Most of the 42 PACs (≤98%) were detected in all matrices.

Multiple stressors including contaminant exposure and parasite infection predict spleen mass and energy expenditure in breeding ring-billed gulls.

Daily energy expenditure (DEE) in animals is influenced by many factors although the impact of stressors remains largely unknown. The objective of this study was to determine how multiple physiological stressors (parasite infection and contaminant exposure) and natural challenges (energy-demanding activities and weather conditions) may affect DEE in nesting ring-billed gulls (Larus delawarensis) exposed to high concentrations of persistent organic contaminants (POPs). Physical activity, temperature, gastrointestinal parasitic worm abundance, relative spleen mass, plasma thyroid hormone levels and liver concentrations of POPs were determined; field metabolic rate (FMR) was used as a measure of DEE.

Spatiotemporal patterns and relationships among the diet, biochemistry, and exposure to flame retardants in an apex avian predator, the peregrine falcon.

Flame retardants (FR) are industrial chemicals and some are proven environmental contaminants that accumulate in predatory birds. Few studies have examined the influence of diet on FR profiles in nestling raptors and the possible physiological implications of such FR exposure. The objectives of this research were (1) to determine spatial patterns of ≤ 48 polybrominated diphenyl ether (PBDE) congeners and ≤ 26 non-PBDE FRs, including organophosphate esters (OPEs), in nestling peregrine falcons (Falco peregrinus) across the Canadian Great Lakes-St.

Disruption of thyroxine and sex hormones by 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (DBE-DBCH) in American kestrels (Falco sparverius) and associations with reproductive and behavioral changes.

1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (DBE-DBCH - formerly TBECH) is an emerging brominated flame retardant (BFR) pollutant with androgen potentiating ability and other endocrine disrupting effects in birds and fish. The objectives of this study were to determine the effects of exposure to environmentally-relevant levels of DBE-DBCH on circulating levels of thyroid and sex steroid hormones in American kestrels, and if hormonal concentrations were related to previously reported changes in reproductive success and courtship behaviors. Sixteen kestrel pairs were exposed to 0.

Transfer of hexabromocyclododecane flame retardant isomers from captive American kestrel eggs to feathers and their association with thyroid hormones and growth.

Feathers are useful for monitoring contaminants in wild birds and are increasingly used to determine persistent organic pollutants. However, few studies have been conducted on birds with known exposure levels. We aimed to determine how well nestling feather concentrations reflect in ovo exposure to hexabromocyclododecane (α-, β- and γ-HBCDD), and to determine if feather concentrations are related to physiological biomarkers.

Sex-specific changes in thyroid gland function and circulating thyroid hormones in nestling American kestrels (Falco sparverius) following embryonic exposure to polybrominated diphenyl ethers by maternal transfer.

High concentrations of polybrominated diphenyl ethers (PBDEs) accumulate in predatory birds. Several PBDE congeners are considered thyroid disruptors; however, avian studies are limited. The authors examined circulating thyroid hormones and thyroid gland function of nestling American kestrels (Falco sparverius) at 17 d to 20 d of age, following embryonic exposure by maternal transfer only to environmentally relevant levels of PBDEs (DE-71 technical mixture).

Short-term fasts increase levels of halogenated flame retardants in tissues of a wild incubating bird.

Many species are adapted for fasting during parts of their life cycle. For species undergoing extreme fasts, lipid stores are mobilized and accumulated contaminants can be released to exert toxicological effects. However, it is unknown if short-term fasting events may have a similar effect.

Field Metabolic Rate Is Dependent on Time-Activity Budget in Ring-Billed Gulls (Larus delawarensis) Breeding in an Anthropogenic Environment.

Environmental and behavioral factors have long been assumed to affect variation in avian field metabolic rate (FMR). However, due to the difficulties in measuring continuous behavior of birds over prolonged periods of time, complete time-activity budgets have rarely been examined in relation to FMR. Our objective was to determine the effect of activity (measured by detailed time-activity budgets) and a series of extrinsic and intrinsic factors on FMR of the omnivorous ring-billed gull (Larus delawarensis).

Exposure to the androgenic brominated flame retardant 1,2-dibromo-4-(1,2-dibromoethyl)-cyclohexane alters reproductive and aggressive behaviors in birds.

Detected in environmental samples, 1,2-dibromo-4-(1,2-dibromoethyl) cyclohexane (DBE-DBCH) is a bioaccumulative isomer of a current-use brominated flame retardant. All 4 structural isomers are androgen agonists; however, little toxicological information exists for this compound. The objective of the present study was to determine if β-DBE-DBCH, the isomer found most prominently in animal tissue, affects androgen-dependent behavior of breeding American kestrels (Falco sparverius).

Uptake, distribution, depletion, and in ovo transfer of isomers of hexabromocyclododecane flame retardant in diet-exposed American kestrels (Falco sparverius).

Hexabromocyclododecane (HBCDD) is a flame retardant and a global contaminant, yet the toxicokinetics of HBCDD diastereoisomers remains unknown in wildlife species. The present study examined in captive American kestrels (Falco sparverius) (diastereo) isomer-specific HBCDD uptake, depletion, tissue distribution, and transfer to eggs in a dietary dosing study with an HBCDD technical mixture (HBCDD-TM). Adult tissue and plasma collections were from separate cohorts of unpaired individual males (n = 10) and females (n = 10) exposed for 21 d to 800 ng/g wet weight of HBCDD-TM (in safflower oil and injected into their cockerel [brain] diet), followed by a 25-d depuration period.

Dietary exposure of American kestrels (Falco sparverius) to decabromodiphenyl ether (BDE-209) flame retardant: uptake, distribution, debromination and cytochrome P450 enzyme induction.

Accumulation and evidence of debromination of the flame retardant 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) have been reported for biota, including raptorial birds, based on PBDE congener residues in tissues and eggs. However, in vivo studies with BDE-209-exposed birds are rare and unknown for a raptorial species. In the present study, males (n=22) of raptorial American kestrels (Falco sparverius) were exposed to 116,000ng of BDE-209 (high purity, >98%; in safflower oil) per day for 21days (~2,436,000ng total BDE-209 exposure over this uptake period), followed by a 25-day depuration period.

Changes in the incubation by American kestrels (Falco sparverius) during exposure to the polybrominated diphenyl ether (PBDE) mixture DE-71.

Polybrominated diphenyl ethers (PBDE) are persistent environmental pollutants that have been detected in wildlife globally. American kestrels exposed to the commercial PBDE mixture DE-71 have previously demonstrated reduced reproductive success and behaviors during courtship and brood rearing; however, it remains unknown whether DE-71 affects incubation. During breeding, captive kestrels were exposed to the DE-71 mixture dissolved in safflower oil at two environmentally relevant concentrations (low: 283.