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Blubber taken from ringed seals (Pusa hispida) during a subsistence hunt at Ulukhaktok, NT (formerly Holman, NWT) at intervals between 2002 and 2015 was analysed for polybrominated diphenyl ether (PBDE) congeners. Results from these analyses were combined with others previously published to yield a data set of 18 tri- to hepta-substituted PBDE congeners in 102 animals sampled over a span of 19 year (females) and 34 year (males). In females, mean total PBDE concentrations increased between 1996 and 2015 by approximately 50%, from 1940 to 2780 pg/g wet wt., although not significantly so (p > 0.05) by one-way ANOVA. In males, concentrations ranged from 376 to 6470 pg/g wet wt. between 1981 and 2015 (p

Ringed seals (Phoca hispida) have been used as bioindicator species of environmental contamination in Canada since the 1970s. In the present study, seals were harvested during subsistence hunts in four regions of the Canadian Arctic: Beaufort Sea, Arctic Archipelago, Hudson Bay, and coastal Labrador. An extensive suite of persistent organic pollutants (POPs) was determined in seal blubber collected for multiple years between 1972 and 2016. Results from this long-term study indicate geographical differences in the contaminant concentrations in seals and the significant general decrease of most POPs, including polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and related compounds, chlordanes (CHL), and hexachlorocyclohexanes (HCH) over time in ringed seals. The highest decrease rates (up to −9.1%/year for α-HCH) were found in seals from the Hudson Bay region where all chemicals investigated have significantly decreased since 1986. Significant increases in concentrations of hexachlorobenzene (HCB) in seals from Labrador and β-HCH in Sachs Harbour, NT and Arctic Archipelago were observed. Site-specific and contaminant-specific associations between climate pattern (i.e., Arctic Oscillation, North Atlantic Oscillation, and Pacific/North American pattern) and mean ice-coverage (total, first-year ice, and old-ice) were found at sites with the longest time trend data (i.e., Arviat, Sachs Harbour/Ulukhaktok and Resolute Bay). Overall, results suggest that North American and international regulations have led to the long-term reduction of most POPs in Canadian Arctic ringed seals by reducing emissions from primary sources. However, other sources of legacy compounds (e.g., environmental reservoirs) as well changes in food web composition and structure in relation to climate changes could also be influencing the very slow rates of decline, or stable levels, of contaminants found in seals at some sites. Further work is warranted to discern between co-variation of climate changes and contaminant concentrations and cause-and-effect relationships.

The present study applies a chemical activity-based approach to: 1) evaluate environmental concentrations of di-ethylhexyl phthalate (DEHP; n = 23 651) and its metabolite mono-ethylhexyl phthalate (MEHP; n = 1232) in 16 environmental media from 1174 studies in the United States, Canada, Europe, and Asia, and in vivo toxicity data from 934 studies in 20 species, as well as in vitro biological activity data from the US Environmental Protection Agency's Toxicity Forecaster and other sources; and 2) conduct a comprehensive environmental risk analysis. The results show that the mean chemical activities of DEHP and MEHP in abiotic environmental samples from locations around the globe are 0.001 and 10-8 , respectively. This indicates that DEHP has reached on average 0.1% of saturation in the abiotic environment. The mean chemical activity of DEHP in biological samples is on average 100-fold lower than that in abiotic samples, likely because of biotransformation of DEHP in biota. Biological responses in both in vivo and in vitro tests occur at chemical activities between 0.01 to 1 for DEHP and between approximately 10-6 and 10-2 for MEHP, suggesting a greater potency of MEHP compared with DEHP. Chemical activities of both DEHP and MEHP in biota samples were less than those causing biological responses in the in vitro bioassays, without exception. A small fraction of chemical activities of DEHP in abiotic environmental samples (i.e., 4-8%) and none (0%) for MEHP were within the range of chemical activities associated with observed toxicological responses in the in vivo tests. The present study illustrates the chemical activity approach for conducting risk analyses. Environ Toxicol Chem 2017;36:1483-1492. © 2016 SETAC.

We explored how currently manufactured feeds, under real-world conditions and across geographically distinct locations, promoted flesh n-3 long-chain polyunsaturated fatty acid (LC-PUFA, i.e. 20:5n-3 + 22:6n-3) levels in various life stages of farmed Atlantic Salmon (Salmo salar). Potential effects on flesh LC-PUFA included: (1) diet and fish weight at one Canadian east coast farm, (2) diet and farm location across six east coast farms, and (3) diet and farm location between east and west coast farms. For objectives 1 and 2, salmon were fed a currently manufactured feed (labelled as feeds A, B or C) and harvested at 1, 3 and 5 kg. LC-PUFA levels in 5 kg (harvest size) fish were then compared to previously published values for west coast farmed Atlantic Salmon (Obj. 3). Combined results revealed that variability in LC-PUFA levels was better explained by diet than by fish weight or farm location. Fish size, however, was also important for two reasons. First, feeding a high LC-PUFA diet early in life appeared important for ensuring high LC-PUFA levels at harvest size. Second, salmon flesh LC-PUFA levels increased with fish size, but only when dietary LC-PUFA was provided above an apparent threshold value (~3000 mg per 100 g or 10% of total fatty acids) that likely promoted LC-PUFA incorporation and storage. Overall, our comparison makes new recommendations for feed manufacturers and demonstrates that farmed Atlantic Salmon reared under real-world conditions on currently available salmon feeds were good sources of n-3 LC-PUFA to consumers.

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) from stain-guard treated carpets in landfills continue to be released into the environment. To understand the leaching of PFASs from carpets to landfill leachate as a function of environmental factors, leaching concentrations of ten perfluoroalkyl carboxylic acids and four perfluoroalkyl sulfonic acids were quantified for different pHs, contact times, mixing speeds, and temperatures. Partitioning from carpet to leachate and distilled water at different pHs showed negligible differences. The total concentration of leaching PFASs in distilled water was approximately 1 ng L(-1) higher than in landfill leachate, indicating that the presence of multivalent cations in leachate could have a negative effect on leaching of PFASs. For all PFASs monitored, leaching increased with increasing contact time and temperature. Perfluorohexanoic and perfluoroheptanoic acids experienced the largest increases with contact time and temperature. Gibbs free energy (ΔG0), enthalpy (ΔH0), and entropy energy (ΔS0) indicated that PFAS leaching from carpet was dominantly controlled by entropy-driven processes and did not differ significantly among individual PFASs. PFAS concentrations in leachate with rotation of an end-over-end contactor were higher than under static conditions, but otherwise, varying the rotation speed had negligible influence. The results provide useful information for management of discarded stain-guard carpets in landfills.

To investigate whether Sediment Quality Guidelines (SQGs) for polychlorinated biphenyls (PCBs) in Canada and British Columbia achieve their objective of protecting ecosystems, we measured and compiled concentrations of PCB congeners in sediments, bivalves, crustaceans, fish, and marine mammals from 3 areas off the Pacific coast of British Columbia, Canada. The concentration data showed that whereas PCB concentrations in sediments were predominantly below the SQG of 20 µg/kg dry weight, large fractions of the PCB concentrations in fish and shellfish species exceeded the tissue residue guideline for the consumption of fish and shellfish by wildlife (i.e., 50 µg/kg wet weight [ww]) but were below the tissue residue guideline for the consumption of fish and shellfish by human populations (i.e., 2000 µg/kg ww). Also, PCB concentrations in marine mammals exceeded toxicity reference concentrations. The concentration data were used to develop species- and location-specific Biota-Sediment Accumulation Factors (BSAF = Cbiota /Csediment ), that were used to estimate PCB concentrations in wildlife species that may exist if the PCB concentration in sediments are equal to the SQGs. The results show that if the PCB concentration is equal to the SQGs, then PCB concentrations in most wildlife species can be expected to exceed the tissue residue guideline for the consumption of fish and shellfish by wildlife species and by humans, as well as toxicity reference concentrations for marine mammals. A methodology for developing SQGs for PCBs that are protective of the health of different wildlife species and human consumers of fish and shellfish from general Canadian and coastal First Nations populations was developed and applied. The proposed guidelines may provide useful guidance to establish SQGs for PCBs that can account for the ecological diversity in coastal environments and that better achieve the intent of the guidelines to protect ecosystems. The proposed methodology for guideline development may also be useful in the development of SQGs for other bioaccumulative substances.

The health of Skeena River Sockeye salmon (Onchorhychus nerka) has been of increasing concern due to declining stock returns over the past decade. In the present work, in-migrating Sockeye from the 2008 run were evaluated using a mass spectrometry-based, targeted metabolomics platform. Our objectives were to (a) investigate natural changes in a subset of the hepatic metabolome arising from migration-associated changes in osmoregulation, locomotion, and gametogenesis, and (b) compare the resultant profiles with animals displaying altered hepatic vitellogenin A (vtg) expression at the spawning grounds, which was previously hypothesized as a marker of xenobiotic exposure. Of 203 metabolites monitored, 95 were consistently observed in Sockeye salmon livers and over half of these changed significantly during in-migration. Among the most dramatic changes in both sexes were a decrease in concentrations of taurine (a major organic osmolyte), carnitine (involved in fatty acid transport), and two major polyunsaturated fatty acids (eicosapentaenoic acid and docosahexaenoic acid). In females, an increase in amino acids was attributed to protein catabolism associated with vitellogenesis. Animals with atypical vtg mRNA expression demonstrated unusual hepatic amino acid, fatty acid, taurine, and carnitine profiles. The cause of these molecular perturbations remains unclear, but may include xenobiotic exposure, natural senescence, and/or interindividual variability. These data provide a benchmark for further investigation into the long-term health of migrating Skeena Sockeye.

The commercial chemotherapeutant formulations SLICE® and AlphaMax® [active ingredients emamectin benzoate (EB) and deltamethrin respectively] are used in fin fish aquaculture to control parasitic sea lice. In some regions, the use of these substances has drawn concern from the commercial fishing industry regarding potential adverse effects on non-target organisms. In the present work, biodegradation of EB and deltamethrin, and their commercial formulations, was investigated over 135 days at 4 and 10°C in fresh marine sediments collected from underneath an active open net-pen salmon farm. EB incubated as either pure substance or commercial formulation was recalcitrant at both temperatures under abiotic and biotic conditions. Deltamethrin incubated alone or as its commercial formulation degraded slowly at 10°C (t1/2 = 330 ± 107 and 201 ± 27.1 days respectively). At 4°C, deltamethrin degradation was only significant following incubation as commercial formulation (t1/2 = 285 ±112 days). Degradation rates of EB and deltamethrin as pure substances versus their commercial formulations were not statistically different. Depletion of deltamethrin was observed in 10°C inactive sediments indicating that transformation occurred (at least in part) via an abiotic pathway. Overall, these data provide further insight into the fate and persistence of EB from the ongoing use of SLICE® in British Columbia's salmon aquaculture industry. AlphaMax® is not registered in Canada but is used in other salmon farming countries to control sea lice.

In blubber of ringed seals (Phoca hispida) from Ulukhaktok, NT, residues of DDT, other organochlorine pesticides, and PCBs declined between 1972 and 2010. The rate of decline varied: concentrations of the DDT-group began to fall after 1981, whereas those of PCBs fell rapidly between 1972 and 1981, and then slowed. Concentrations of cis- and trans-chlordane and of HCB in both sexes, and of cis-nonachlor in males, declined slowly between 1978 and 2010; those of other organochlorine pesticides remained steady. Exponential half-lives of p,p′-DDT and p,p′-DDE in female seals are about 9 and 36 y (corresponding to initial declines of 7.8% and 1.9% per year, respectively) and those of PCB congeners from about 20 to 60 y (declines of 3.2% to

Previous research on brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs) has largely focussed on their concentrations in the environment and their adverse effects on human health. This paper explores their transfer from waste streams to water and soil. A comprehensive mass balance model is developed to track polybrominated diphenyl ethers (PBDEs), originating from e-waste and non-e-waste solids leaching from a landfill. Stepwise debromination is assumed to occur in three sub-systems (e-waste, aqueous leachate phase, and non-e-waste solids). Analysis of landfill samples and laboratory results from a solid-liquid contacting chamber are used to estimate model parameters to simulate an urban landfill system, for past and future scenarios. Sensitivity tests to key model parameters were conducted. Lower BDEs require more time to disappear than high-molecular weight PBDEs, since debromination takes place in a stepwise manner, according to the simplified reaction scheme. Interphase mass transfer causes the decay pattern to be similar in all three sub-systems. The aqueous phase is predicted to be the first sub-system to eliminate PBDEs if their input to the landfill were to be stopped. The non-e-waste solids would be next, followed by the e-waste sub-system. The model shows that mass transfer is not rate-limiting, but the evolution over time depends on the kinetic degradation parameters. Experimental scatter makes model testing difficult. Nevertheless, the model provides qualitative understanding of the influence of key variables.

Reductions in flesh contaminant concentrations were evaluated in a 36-week feeding trial examining several dietary techniques. Atlantic salmon were fed one of seven dietary treatments for 24 weeks. These diets included a fishmeal, fish oil control diet, an industry control diet, three diets that examined a 75% replacement level of anchovy oil (AO) with flaxseed oil, canola oil and poultry fat, and two diets formulated to be low in contaminants formulated with canola oil, activated carbon-treated anchovy oil and canola protein concentrate or soy protein concentrate. Following this initial 24-week feeding interval, a 12-week finishing diet was utilized to restore the levels of omega-3 highly unsaturated fatty acids (n-3 HUFAs). The salmon had marked reductions in their flesh concentrations of total polychlorinated biphenyls (PCBs), dioxin-like PCBs and total toxic equivalents by the end of the grow-out phase, but also exhibited significant depressions in their flesh concentrations of n-3 HUFAs relative to 100AO-fed fish. The 12-week finishing diet period was effective in partially re-instating omega-3 levels to those present in the flesh lipids of fish fed 100AO while concurrently maintaining lower flesh contaminant concentrations.

Experiments and analysis were carried out by contacting e-waste with distilled water and leachate from a major urban landfill. Contacting of crushed e-waste from different eras with leachate in a custom built end-over-end contactor led to appreciable mass transfer of Polybrominated diphenyl ethers (PBDEs) to the aqueous phase. Temperature had limited influence for the limited range (10-25°C) investigated. Lower pH (in the range 4 to 9) generally resulted in higher transfer of PBDEs to the aqueous phase. Exposing e-waste to distilled water in the same contactor led to lower, but still appreciable PBDE analysed concentrations, than for leachate, probably due to dislodgement of fine dust from the surface of the e-waste particles.

The health of sockeye (Oncorhynchus nerka) salmon stocks is of increasing concern; reflecting both a sentinel of human-impacted aquatic environments and as a key fishery for British Columbia, Canada. The spawning migration of Pacific sockeye salmon represents a critical life stage where significant demands are made on animal biology and important BC fisheries are linked to this migration in the Skeena and Fraser River watersheds. These watersheds present very different environments; the former being sparsely populated with little industrial impact, while the latter flows through highly-populated areas. The present study used quantitative real-time PCR analysis of adult sockeye salmon from four 2008 stocks [Fulton River and Pinkut Creek (Skeena) and Weaver Creek and Harrison River (Fraser)] to evaluate ten hepatic gene transcripts associated with reproduction, stress, energy metabolism, and exposure to environmental contaminants. Dynamic changes in mRNA abundance were observed in Fulton River stock animals from the Skeena River mouth to the spawning ground which reflect the physiological demands of in-river migration and reproductive maturation. Inter-stock comparisons of migrants at spawning grounds demonstrated a marked difference in the sex-specific gene hepatic gene expression profiles. Our original hypothesis was that a greater diversity in mRNA profiles is associated with watersheds with higher human impact. However, our observations contradict this posit. Skeena males and females displayed poor definition in their molecular profiles between sexes while the Fraser River fish had very distinctive sex differences that were consistent with the previous year's migration. The genetic sex distribution and ratio of milt versus roe production did not differ between the Skeena and Fraser River spawning site fish. However, a significant percentage of Skeena animals displayed marked discordance of these characteristics with gender-specific hepatic mRNA profiles implying that an alteration in estrogen-mediated signaling has occurred. Continued geospatial and longitudinal assessments will help determine to what extent the dynamic molecular biology of late life-stage sockeye salmon reflects natural variation or modulation by anthropogenic causative agents.

Investigations into the biodegradation potential of perfluorooctane sulfonate (PFOS)-precursor candidates have focused on low molecular weight substances (e.g., N-ethyl perfluorooctane sulfonamido ethanol (EtFOSE)) in wastewater treatment plant sludge. Few data are available on PFOS-precursor biodegradation in other environmental compartments, and nothing is known about the stability of high-molecular-weight perfluorooctane sulfonamide-based substances such as the EtFOSE-based phosphate diester (SAmPAP diester) in any environmental compartment. In the present work, the biodegradation potential of SAmPAP diester and EtFOSE by bacteria in marine sediments was evaluated over 120 days at 4 and 25 °C. At both temperatures, EtFOSE was transformed to a suite of products, including N-ethyl perfluorooctane sulfonamidoacetate, perfluorooctane sulfonamidoacetate, N-ethyl perfluorooctane sulfonamide, perfluorooctane sulfonamide, and perfluorooctane sulfonate. Transformation was significantly more rapid at 25 °C (t(1/2) = 44 ± 3.4 days; error represents standard error of the mean (SEM)) compared to 4 °C (t(1/2) = 160 ± 17 days), but much longer than previous biodegradation studies involving EtFOSE in sludge (t(1/2) ∼0.7-4.2 days). In contrast, SAmPAP diester was highly recalcitrant to microbial degradation, with negligible loss and/or associated product formation observed after 120 days at both temperatures, and an estimated half-life of >380 days at 25 °C (estimated using the lower bounds 95% confidence interval of the slope). We hypothesize that the hydrophobicity of SAmPAP diester reduces its bioavailability, thus limiting biotransformation by bacteria in sediments. The lengthy biodegradation half-life of EtFOSE and recalcitrant nature of SAmPAP diester in part explains the elevated concentrations of PFOS-precursors observed in urban marine sediments from Canada, Japan, and the U.S, over a decade after phase-out of their production and commercial application in these countries.

The present study applies a chemical activity-based approach to: 1) evaluate environmental concentrations of di-ethylhexyl phthalate (DEHP; n = 23 651) and its metabolite mono-ethylhexyl phthalate (MEHP; n = 1232) in 16 environmental media from 1174 studies in the United States, Canada, Europe, and Asia, and in vivo toxicity data from 934 studies in 20 species, as well as in vitro biological activity data from the US Environmental Protection Agency's Toxicity Forecaster and other sources; and 2) conduct a comprehensive environmental risk analysis. The results show that the mean chemical activities of DEHP and MEHP in abiotic environmental samples from locations around the globe are 0.001 and 10

Concentrations and isomer profiles for 24 per- and polyfluoroalkyl substances (PFASs) were monitored over 5 months (February-June, 2010) in municipal landfill leachate. These data were used to assess the role of perfluoroalkyl acid (PFAA) precursor degradation on changes in PFAA concentrations over time. The influence of total organic carbon, total suspended solids, pH, electrical conductivity (EC), leachate flow rates, and meteorological data (precipitation, air temperature) on leachate PFAS concentrations was also investigated. Perfluoropentanoate and perfluorohexanoate were typically the dominant PFASs in leachate, except for March-April, when concentrations of perfluorooctane sulfonate, perfluorooctanoate, and numerous PFAA-precursors (i.e., (N-alkyl) perfluorooctane sulfonamides and fluorotelomer carboxylic acids) increased by a factor of 2-10 (~4 μg/L to ~36 μg/L ΣPFASs). During this time, isomer profiles of PFOA became increasingly dominated by the linear isomer, likely from transformation of linear, telomer-manufactured precursors. While ΣPFAA-precursors accounted for up to 71% of ΣPFASs (molar basis) in leachate from this site, leachate from a second landfill displayed only low concentrations of precursors (1% of ΣPFASs). Overall, degradation of PFAA-precursors and changes in leachate pH, EC, and 24-h precipitation were important factors controlling PFAS occurrence in leachate. Finally, 8.5-25 kg/yr (mean 16 kg/yr) of ΣPFASs was estimated to leave the landfill via leachate for subsequent treatment at a wastewater treatment plant.

The objective of this study was to access the suitability of using poultry fat (PF) or blends of PF with flaxseed oil (FO) to replace 75% of the supplemental anchovy oil (AO) in the diet of juvenile sablefish (Anoplopoma fimbria), a relatively new marine species to aquaculture. Sablefish were fed one of four diets twice daily to satiation for 15 weeks. The test diets were identical in composition except for the source of supplemental lipid which was either 100% AO (100AO), or had 75% of the supplemental AO replaced with 50% FO:25% PF, 25% FO:50% PF or 75% PF. Sablefish growth parameters, whole body and fillet proximate constituent concentrations, and apparent digestibility coefficients were uninfluenced by diet treatment. There were also no adverse effects of the diet treatments on fish health, as determined from analysis of various haematological and innate immunological parameters. Terminal fillet fatty acid compositions generally reflected the dietary fatty acid compositions. Results indicated that PF or blends of PF and FO may comprise 75% of the supplemental lipid in a grower diet for sablefish and are an economic alternative to AO while still providing humans with a rich dietary source of highly unsaturated fatty acids.

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Two of the most common products currently used to control parasitic sea lice in fin fish aquaculture, salmon in particular, are Slice® and AlphaMax®. Emamectin benzoate (EB) is the active ingredient in Slice® and deltamethrin is the active ingredient in AlphaMax®. Several analytical methods have been developed for the determination of the active ingredients in these products but these have been focused on specific matrices and lack the sensitivity and versatility required in environmental monitoring. Here we present a validated, versatile, and simple analytical method for the determination of EB, its desmethyl degradation product (AB), and deltamethrin in a wide range of environmental matrices (sea water, marine sediment, and tissue). Sediments and tissues were extracted by accelerated solvent extraction (ASE®) and sample cleanup was achieved by solid phase extraction (SPE) while sea water was extracted using SPE disks. Analyte identification and quantification was based on liquid chromatography tandem ma...

The environmental occurrence of perfluorooctane sulfonate (PFOS) can arise from its direct use as well as from transformation of precursors ((N-alkyl substituted) perfluorooctane sulfonamides; FOSAMs). Perfluorooctane sulfonamidoethanol-based phosphate (SAmPAP) esters are among numerous potential PFOS-precursors which have not been previously detected in the environment and for which little is known about their stability. Based on their high production volume during the 1970s-2002 and widespread use in food contact paper and packaging, SAmPAP esters may be potentially significant sources of PFOS. Here we report for the first time on the environmental occurrence of SAmPAP diester in marine sediments from an urbanized marine harbor in Vancouver, Canada. SAmPAP diester concentrations in sediment (40-200 pg/g dry weight) were similar to those of PFOS (71-180 pg/g). A significant (p0.05) correlation was observed between SAmPAP diester and N-ethyl perfluorooctane sulfonamido acetate (an anticipated degradation product of SAmPAP diester). ∑PFOS-precursor (FOSAM) concentrations in sediment (120-1100 pg/g) were 1.6-24 times greater than those of PFOS in sediment. Although SAmPAP diester was not detected in water, PFOS was observed at concentrations up to 710 pg/L. Among the per- and polyfluoroalkyl substances monitored in the present work, mean log-transformed sediment/water distribution coefficients ranged from 2.3 to 4.3 and increased with number of CF(2) units and N-alkyl substitution (in the case of FOSAMs). Overall, these results highlight the importance of FOSAMs as potentially significant sources of PFOS, in particular for urban marine environments.

This experiment investigated a range of dietary nicarbazin concentrations for efficacy against the myxosporean parasite Kudoa thyrsites and for toxicity in seawater-reared Atlantic salmon post-smolts. Nicarbazin was incorporated into diets at 0 (control), 2.5, 5, 10 or 25 g kg− 1 such that each dose was replicated among three tanks and delivered intermittently over 2155 degree-days. Compared with controls, the prevalence and severity of K. thyrsites, determined histologically, were significantly reduced in fish fed diets containing nicarbazin. Nicarbazin residues in skeletal muscle, liver and skin were proportional to dietary concentration between 0 and 10 g kg− 1 and were associated with a red discolouration of the skin. Cumulative mortality ranged from 0% to 12.4% among groups and was significantly elevated in the 10 and 25 g kg− 1 groups, relative to control. Weight and condition factor were reduced because of reduced feeding responses to the medicated diets. Feeding responses and appearance of the skin returned to normal and mortality ceased upon resumption of non-medicated diets. In conclusion, dietary nicarbazin was efficacious against K. thyrsites in Atlantic salmon, when included in diets at concentration of at least 2.5 g kg− 1. Further research will optimise nicarbazin treatment strategies and establish tissue residues following cessation of treatment.

The potential impact of commercial salmon aquaculture along the coast of British Columbia on the health of non-target marine wildlife is of growing concern. In the current initiative, the biological effects on gene expression within spot prawn (Pandalus platyceros) exposed to the sea lice controlling agent, emamectin benzoate (EB; 0.1–4.8 mg/kg sediment), were investigated. A mean sediment/water partitioning coefficient (Kp) was determined to be 21.81 and significant levels of EB were detected in the tail muscle tissue in all exposed animals. Animals selected for the experiment did not have eggs and were of similar weight. Significant mortality was observed within 8 days of EB treatment at concentrations between 0.1 and 0.8 mg/kg and there was no effect of EB on molting. Twelve spot prawn cDNA sequences were isolated from the tail muscle either by directed cloning or subtractive hybridization of control versus EB exposed tissues. Three of the transcripts most affected by EB exposure matched sequences encoding the 60S ribosomal protein L22, spliceosome RNA helicase WM6/UAP56, and the intracellular signal mediator histidine triad nucleotide binding protein 1 suggesting that translation, transcription regulation, and apoptosis pathways were impacted. The mRNA encoding the molting enzyme, β-N-acetylglucosaminidase, was not affected by EB treatment. However, the expression of this transcript was extremely variable making it unsuitable for effects assessment. The results suggest that short-term exposure to EB can impact biological processes within this non-target crustacean.

We sampled an abundant, native minnow (Longnose dace—Rhinichthys cataractae) throughout the Oldman River, Alberta, to determine physiological responses and possible population level consequences from exposure to compounds with hormone-like activity. Sex ratios varied between sites, were female-biased, and ranged from just over 50% to almost 90%. Histological examination of gonads revealed that at the sites with >60% females in the adult population, there was up to 38% occurrence of intersex gonads in fish identified through visual examination of the gonads as male. In the majority of intersex gonad cases, there was a large proportion (approx., 50%) of oocytes within the testicular tissue. In male dace, vitellogenin mRNA expression generally increased with distance downstream. We analyzed river water for 28 endocrine disrupting compounds from eight functional classes, most with confirmed estrogen-like activity, including synthetic estrogens and hormone therapy drugs characteristic of municipal wastewater effluent, plus natural hormones and veterinary pharmaceuticals characteristic of livestock production. The spatial correlation between detected chemical residues and effects to dace physiology indicate that multiple land uses have a cumulative impact on dace in the Oldman River and effects range from altered gene regulation to severely female-biased sex ratios.

Polybrominated diphenyl ethers (PBDEs) have been found at high levels, up to 7.6 × 106 pg/g, in biosolids commonly applied to agricultural soils. A field investigation was carried out in this study to measure concentrations of PBDEs in biosolid-amended agricultural soils in which various amounts of biosolids (20 and 80 t/ha) had been applied. Concentrations of PBDEs in surface soils that had received a single application of 80 t/ha biosolids were one to two orders of magnitude greater than that in soil, which had received a single application of 20 t/ha of biosolids. Assessment of PBDEs levels at different depths, between 0.05 and 1.05 m, in soils that received 80 t/ha biosolids, showed that PBDEs were mobilized from the surface soil to lower depths. Total PBDEs concentrations decreased from 10,250 pg/g dry weight basis (dw) in the 0.05 m soil layer to 220 pg/g dw at a depth of 1 m. The distribution of PBDEs with depth and cation exchange capacity of the soil could be described as exponential functions. The coefficients of correlation ranged from 0.47 to 0.57 and 0.47 to 0.67, respectively. Despite the deviation in the experimental measurements induced by variables, such as non-uniform biosolid application, heterogeneity of the soil, and the uneven surface of the field, variations of PBDEs along the soil profile in the biosolid-amended soil were clearly demonstrated.

This study was undertaken to determine the suitability of using cold-pressed flaxseed oil (FO) as a major source of lipid in place of anchovy oil (AO) in the diet of juvenile sablefish (Anoplopoma fimbria), a relatively new marine species to aquaculture. Sablefish were fed one of four diets twice daily to satiation for 15 weeks. The test diets were identical in composition, except for the source of supplemental lipid which was either 100% AO (100AO), or increasing replacement of AO with FO i.e., 75AO:25FO, 50AO:50 FO or 25AO:75FO. Sablefish growth parameters, whole body and fillet proximate constituent concentrations and apparent digestibility coefficients were uninfluenced by diet treatment. There were also no adverse effects of the diet treatments on fish health, as determined from analysis of various haematological and innate immunological parameters. Terminal fillet fatty acid compositions generally reflected the dietary fatty acid compositions, while flesh contaminant concentration decreased with increasing dietary flaxseed oil content. Results indicated that FO may comprise up to 75% of the supplemental lipid in a grower diet for sablefish, while still providing humans with a rich dietary source of highly unsaturated fatty acids.

The present study reports measured levels of organochlorine pesticides (OCPs) in commercial salmon feed (n = 8) and farmed Atlantic, coho, and chinook salmon (n = 110), as well as wild coho, chinook, chum, sockeye, and pink salmon (n = 91). Flesh residue concentrations (ng/g wet weight) of dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), chlordanes, chlorobenzenes (CBz) and cyclodiene pesticides (e.g., dieldrin, mirex) were 2 to 11 times higher (p 0.05) in farmed salmon compared with wild salmon. Concentrations were positively correlated with flesh lipid levels. Farmed Atlantic salmon (12-15% lipid) typically exhibited the greatest OCP burdens compared with other salmon species. However, when expressed on a lipid weight basis, concentrations of OCPs (ng/g lipid weight) in wild salmon, in many cases, exceeded those levels in farmed salmon. Observed interspecies and site-specific variations of OCP concentrations in farmed and wild salmon may be attributed to divergent life history, prey/feed characteristics and composition, bioenergetics, or ambient environmental concentrations. Calculated biomagnification factors (BMF = C(F)/C(D), lipid wt) of OCPs in farmed salmon typically ranged between two and five. Biomagnification of chemicals such as DDTs, chlordanes, and mirex was anticipated, because those compounds tend to exhibit high dietary uptake and slow depuration rates in fish because of relatively high octanol-water partition coefficients (K(OW)s 10⁵). Surprisingly, less hydrophobic pesticides such as hexachlorocyclohexanes and endosulfans (K(OW) s 10⁵) consistently exhibited a high degree of biomagnification in farmed salmon species (BMFs 5). This is contrary to previous laboratory and field observations demonstrating fish BMFs less than 1 for low K(OW) chemicals, because of efficient respiratory elimination of those compounds via gills. The results suggest that ambient seawater concentrations and bioconcentration-driven accumulation may play a key role in the bioaccumulation of these relatively more water-soluble contaminants in farmed salmon. Finally, OCP exposure through consumption of British Columbian salmon is found to be low relative to United States national average per capita total exposure levels and provisional tolerable daily intakes.

Leaching column tests were conducted to determine the mobility of polybrominated diphenyl ethers (PBDEs) in biosolids-amended soils. Deionized water was introduced from the bottom of a glass leaching column containing a 14-mm layer of biosolids-amended soils (210 g) under 42 mm of agricultural soil (600 g). After 4 weeks of leaching, 3.75 L of deionized water had passed through the 210-g biosolids–soil layer and 600 g soil, corresponding to 34 volumes of the leachate per volume of solid. The agricultural soil was divided into three 14-mm layers to determine the PBDE distribution along the flow path of the infiltrating water. PBDEs were found to leach from the biosolids-amended soils layer and migrate through the soil. The predominant congeners BDE47, 85, 99, 100, 153, 154, 183, and 209 decreased to 3–98% of their initial concentrations in the biosolids-amended soil, whereas the total concentration of these eight congeners decreased by 38%. PBDE concentrations in the first 14-mm soil layer increased from not detected (nd) to up to 234 × 103 pg/g dry weight basis (dw). Concentrations in the second and third soil layers increased from nd to 20 and 25 pg/g dw. PBDE in the leachate increased from nd to 310 × 103 pg/L. Mobilization of PBDEs is likely associated with dissolved organic matter and colloids in the infiltrating water.

In the flesh (skinless fillet) of chinook, chum, coho, pink, and sockeye salmon (Oncorhynchus tshawytscha, O. keta, O. kisutch, O. gorbuscha, and O. nerka, respectively), sablefish (Anoplopoma fimbria) and walleye pollock (Theragra chalcogramma) from several sites in the northeast Pacific sampled between 2002 and 2008, tetra- and pentabrominated diphenyl ethers (BDEs) (BDE 47, 49, 99, and 100) dominated the congener distribution. Chinook and sablefish contained the highest concentrations, followed by sockeye, coho, and pink salmon, and pollock. In sockeye from the Bering Sea – Aleutians and from the Gulf of Alaska, total tri- to hepta-BDE concentrations fell significantly between 2002 and 2005; in sablefish from Gulf of Alaska, there was a steady but statistically nonsignificant decline in BDE concentrations between 2002 and 2008. Relative proportions of the main BDE congeners did not change appreciably over time, within species or location. All species except sockeye salmon showed a clear southeastward increase in BDE concentrations, implying an increasing gradient in general ecosystem contamination. In chinook, coho, and sablefish, especially, the southeastward trend in increasing total concentrations was associated with increasing proportions of BDEs 47 and 100. Chinook returning to western North American natal streams appeared to accumulate most of their PBDE burden towards the end of their migration. Fish from more northern sampling sites often had higher proportions of more highly brominated congeners than those from more southern sites, perhaps reflecting contamination from Asian sources where higher-brominated commercial PBDE formulations are used. In sablefish and pollock, the relative proportions of BDEs 99 and 47 varied inversely in almost a 1:1 ratio, implying debromination of BDE 99 to 47. Environ. Toxicol. Chem. 2011; 30:1261–1271. © 2011 SETAC

0-DDE Health risk abstract We characterize for the first time the presence of DDT and its metabolites in tropical Galapagos sea lions (Zalophus wolleabeki). P DDT concentrations in Galapagos sea lion pups sampled in 2005 and 2008 ranged from 16 to 3070 lg/kg lipid. Concentrations of P DDT in pups in 2008 averaged 525 lg/kg lipid and were 1.9 times higher than that (281 lg/kg lipid) detected in pups in 2005. These concentrations are lower than those reported in many pinnipeds elsewhere, comparable to those in Hawaiian monk seals, and higher than those in southern elephant seals. The health risk characterization showed that 1% of the male pups exceeded the p,p 0-DDE toxic effect concentration associated with anti-androgenic effects reported in rats. The findings provide preliminary guidance on the relationship between DDT use and ecological impacts, serving as a reference point against which possible future impact of tropical DDT use can be assessed.

Dichlorodiphenyltrichloroethane (DDT) is an effective and relatively cheap anti-malaria pesticide which has saved human lives, but also brought Northern wildlife species to the brink of extinction due to its persistence, bioaccumulation in the food-web, and hormone-mimicking characteristics (Carson 1962; Vallack et al. 1998; UNEP 2001; ATSDR 2002; Blus 2003; WHO 2006; Colborn and Carroll 2007; Van den Berg 2008). Thirty-two years after its ban in the US and its inclusion on Schedule 2 of the UN Stockholm Convention on Persistent Organic Pollutants (POPs) because of its damaging health effects in human and wildlife populations (UNEP 2001; ATSDR 2002; WHO 2006; Vallack et al. 1998; Colborn and Carroll 2007; Blus 2003), the WHO has recommitted to the use of the malaria-fighting pesticide DDT in tropical countries because of an increase in malaria cases in tropical countries (e. g., Peru, Bolivia, Paraguay, Brazil, and African nations), where DDT use was halted or low application rates were used (Van den Berg 2008; WHO 2006; Roberts et al. 1997, 2000). Although evolutionary adaptation of the malaria vector has triggered insecticide resistance to DDT (Denholm et al. 2002), the return to an increased reliance on DDT use is testament to DDT’s effectiveness in combating malaria at a low cost. Large volumes of DDT (i.e., 4,000–5,000 tonnes of active ingredient per year) were used in India and Africa countries to overcome the malaria crisis (Van den Berg 2008). However, 50 years of research on DDT in the temperate and arctic regions of the Northern hemisphere have documented that human health benefits go hand in hand with detrimental effects on wildlife populations (Carson 1962; De Guise et al. 1998; Lahvis et al. 1995; Guillette et al. 1994; Blus 2003;). Since wildlife provides life support, sustenance, and economic opportunities through harvesting and ecotourism in many developing tropical countries, the health of wildlife cannot be viewed in isolation of human health. A balance needs to be struck between health benefits and health risks of DDT use. This requires an understanding of the fate, trends, and dose–response relationship for DDT in tropical wildlife. Such information does currently not exist and monitoring and source control programs that can help to document this relationship are as absent in tropical countries to date as they were in the Western world when DDT was first used in the 1940s and 1960s (Roberts et al. 2000; ATSDR 2002; Blus 2003; Colborn and Carroll 2007; Van den Berg 2008). From a global perspective, the protection of coastal food webs from contamination by chemical pollutants is critical to the long term conservation of the biodiversity and native inhabitants residing in unique places of the Earth, including UNESCO Global Heritage sites such as the Galapagos Islands. Coastal waters that are contaminated with persistent chemicals and pathogens can lead to human illness and adverse health, reduced fisheries quality and quantity, and impacts of the health of marine wildlife. This had obvious social and economic consequences. Conversely, coastal waters that are protected from chemical pollutants provide for an abundance of clean fisheries products and wildlife, and essential foundation for the well-being of the local biodiversity, human residents and the ecotourism sector. At the top of the marine-coastal food chain, marine mammals can provide an “integrated” overview of ecosystem health. As aquatic animals, they are also vulnerable to infection by pathogens of terrestrial origin. By documenting the presence of chemical pollutants in this species, we are able to deliver science-based advice to conservationists, managers, regulators, and stakeholders, on the implementation of best management practices. Equivalent to the role of killer whales as global sentinels of pollution in the Northeastern Pacific, the Galapagos sea lion has recently been used as a sentinel of marine pollution and a key indicator of the ecosystem functioning and oceanic-coastal environmental health in Galapagos Islands. Therefore, this synopsis aims to synthesize our recent findings on DDT contamination in Galapagos sea lions and its use as a sentinel-model species of environmental pollution by POPs.

We report measured concentrations of organohalogens and trace elements in muscle and eggs of returning wild Pacific sockeye and chinook salmon during their 2007 migration through the Fraser River watershed in Canada. Chemical analyses revealed the presence of ppb to ppm levels of a wide variety of contaminants in these fish, including polychlorinated biphenyls (PCBs); polychlorinated dibenzo-p-dioxins (PCDDs); polychlorinated dibenzofurans (PCDFs); polybrominated diphenyl ethers (PBDEs); organochlorine pesticides (OCPs) such as DDTs, hexachlorocyclohexanes (HCHs), octachlorostyrene, and cyclodienes; and Hg, As, Cd, Pb, and several other trace elements. Body weights and flesh lipid contents declined during upstream migration, resulting in significantly higher (p0.05) lipid-normalized concentrations of lipophilic organohalogens (PCBs, PCDD/Fs, pesticides) in those spawning salmon. Postmigration magnification factors (MFs) of organohalogens (0.1-10) were comparable to previous observations and model predictions. MFs generally increased with increasing hydrophobicity (K(OW)). For example, MFs of tetra- and pentachlorobenzenes and HCH isomers (log K(OW) range: 3.8-5) were relatively low (between 0.1 and 1.7) compared with those of more lipophilic compounds (log K(OW) 6) such as PCBs, DDTs, and mirex (MFs between 5 and 10). Lipid-normalized muscle:egg ratios in female salmon, which varied between 0.1 and 8, also exhibited a positive relationship with chemical K(OW). The results indicate that lipophilic compounds (K(OW) 10(6)) can be magnified in flesh lipids of Pacific salmon during spawning migration, but maternal transfer kinetics (deposition to eggs) of those chemicals are relatively slow compared with less hydrophobic compounds. 2,3,7,8-TCDD toxic equivalents (ΣTEQs) in eggs of these spawning salmon, calculated using WHO toxic equivalency factors (WHO-TEFs) for fish health, in some cases exceeded the 0.3 pg·g(-1) threshold level associated with 30% salmonid egg mortality, indicating the potential for reproductive impacts in Fraser River salmon populations.

In the current study, 28 organic contaminants were measured, many with estrogen-like activity, in water collected from 16 sites on two rivers in the South Saskatchewan River Basin, Alberta, Canada. The compounds detected included synthetic estrogens (birth control pill compounds and hormone therapy drugs) downstream of municipal wastewater effluents and natural hormones downstream of municipal wastewater effluents and in agricultural areas. Greater concentrations of cholesterol and derivatives, phytosterols, and fecal sterols were measured at the most downstream sites, which indicates cumulative inputs of such compounds in these rivers. A native minnow (longnose dace, Rhinichthys cataractae) was sampled to assess pathophysiological responses to exposure to compounds with estrogen-like activity. Hepatic vitellogenin protein was detected in at least one adult male longnose dace from 14 of 15 sites sampled for fish. Vitellogenin was negatively correlated with hepatosomatic (r = −0.47, p

The health and physiological condition of anadromous salmon is of concern as their upriver migration requires navigation of human-impacted waterways and metabolism of stored energy reserves containing anthropogenic contaminants. Such factors may affect reproductive success of fish stocks. This study investigates chemical contaminant burdens and select gene expression profiles in Pacific Sockeye (Oncorhynchus nerka) and Chinook (Oncorhynchus tshawytscha) salmon which traverse the Fraser River watershed during their spawning migration. Chemical analyses of muscle tissue and eggs of salmon collected from the lower Fraser River (pre-migration) and from upstream spawning grounds (post-migration) during the 2007 migration revealed the presence of numerous chemical contaminants, including PCBs, dioxins/furans, pesticides, and heavy metals. However, muscle tissue residue concentrations were well below human health consumption guidelines and 2,3,7,8 TCDD toxic equivalents (ΣTEQs) in salmon eggs, calculated using WHO toxic equivalency factors (WHO-TEFs) for fish health, did not exceed the 0.3 pg g−1 wet weight toxicological threshold level previously associated with 30% egg mortality in salmon populations. Quantitative real-time PCR probes were generated and used to assess differences in abundance of key mRNA transcripts encoding nine gene products associated with reproduction, stress, metal toxicity, and exposure to environmental contaminants. Gene expression profiles were characterized in liver and muscle tissue of pre- and post-migration Sockeye and Chinook salmon. The results of stock-matched animals indicate that dynamic changes in mRNA levels occur for a number of genes in both species during migration and suggest that Sockeye salmon exhibit a greater level of biological stress compared to the Chinook salmon population. Using a male-specific genotypic marker, we found that out of the 154 animals examined, one Sockeye was genotypically male but phenotypically female. This individual's gene expression profile in liver and muscle was reminiscent of, but not identical to, the female expression profile. These studies provide the first glimpse of the dynamic yet common nature of changes in the transcriptome that are shared between species during in-migration and highlight differences that may relate to population success. Continued longitudinal assessment will further define the association between contaminant burden, physiological stress, and modulation of gene expression in migrating Pacific salmon.

Marine fish oils (MFO) are used in salmon diets to mimic the natural diet, to ensure that essential fatty acid requirements for good fish growth and health are met, and to provide salmon flesh with an omega-3 highly unsaturated fatty acid content that can benefit human health. However, an extensive use of MFO in formulated salmonid diets is perceived as an unsustainable use of wild marine fish stocks. In addition, MFOs have a background level of persistent organic pollutants (POPs) unrelated to aquaculture practices. This review considers recently completed studies using alternative lipid sources of terrestrial origin as replacements for MFO and shows that the composition of conventional finfish diets can be altered to reduce the reliance on MFO while concurrently maintaining fish health as well as reducing background levels of POPs. A challenge still ahead is the need for a concerted and sustained outreach to ensure that the public is aware of such improvements to seafood quality so that the preoccupation of the news media with presenting negative images of fish culture to the public is combated.

Trends in alpha-, beta-, and gamma-hexachlorocyclohexane (HCH) concentrations were examined in blubber lipid of ringed seals (Phoca hispida) from Ulukhaktok (Holman), NT (Canada) sampled at intervals between 1978 and 2006. alpha-HCH usually represented approximately 90% of the total HCH isomers. alpha-HCH and gamma-HCH concentrations showed no change over the sampling interval, but beta-HCH concentrations increased significantly, about 8-10-fold in females and 4-5-fold in males. Residue concentrations showed no dependence on age. Concentrations (all data as ng/g lipid, GM (range)) of alpha-HCH were significantly higher (P0.001 by t-test) in males (217 (93.9-517), n=37) than those in females (138 (40.9-402), n=38). beta-HCH concentrations did not differ between the sexes. Concentrations of gamma-HCH were significantly higher (P0.05) in males (6.74 (0-46.7)) than in females (4.35 (0-19.0)). Although global emissions of both alpha-HCH and beta-HCH have declined since the early 1980's, the "signal" of HCH emission changes has not yet resulted in a "response" in ringed seal residue concentrations. In the light of our current understanding of the dynamics of HCH in the Arctic, we conclude that any such response may not be detected by retrospective analyses of the sort describe here at least for another decade or so, because of the longevity of the seals.

To assess occupational exposure, we determined the concentrations of PCDD/Fs and PCBs in human serum samples from 26 incinerator workers (10 industrial waste and 16 municipal solid waste incinerator workers), 38 residents near the facilities and 7 inhabitants (as control subjects) living over 10 km away from any incinerator facilities in Korea. The mean TEQWHO levels of PCDD/Fs in the industrial and MSWI workers were 41.57 and 9.86 pg TEQWHO g−1 lipid, respectively. For the residents, the mean TEQWHO was 13.47 pg TEQWHO g−1 lipid (residents near IWI, MSWI, and control subjects: 17.64, 13.31, and 6.91 pg TEQWHO g−1 lipid). Higher levels of certain PCDD/F congeners, mainly PCDFs, were detected in the serum of industrial incinerator workers in comparison to the levels measured in the residents. Significant differences were observed for PCDFs, the major compounds were OCDF, 1,2,3,4,6,7,8-HpCDF, and the minor components 1,2,3,4,7,8-HxCDF, 1,2,3,6,7,8-HxCDF, and 2,3,4,6,7,8-HxCDF (p

Recent studies have reported the occurrence of persistent organic pollutants (POPs) in commercial feeds used by fish hatcheries and aquaculture facilities. We measured levels of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzo furans (PCDFs), as well as several organochlorine pesticides (OCPs) in several aquafeeds as well as fry and smolts collected from four federal salmonid hatcheries from coastal British Columbia. ΣPCBs in aquafeed samples (n = 22) averaged 270 ± 136 ng/g lipid. ΣDDTs, ΣToxaphene, ΣChlordanes, ΣChlorobenzenes, ΣHexachlorocyclohexanes, dieldrin, endrin and pentachloroanisole in feeds ranged between 0.6 and 200 ng/g lipid. ΣPCDD/F levels in feed samples were relatively low (77 ± 50 pg/g lipid). In some cases, contaminant levels and patterns varied between different feed brands (i.e., Moore–Clarke, EWOS and OMP). ∑PCB concentrations (ng/g lipid) in Moore–Clarke (154.3 ± 88.9) were significantly lower (p

To assess levels and patterns of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in polar regions, XAD-resin based passive air samplers were deployed for one year at the Korean polar research stations at Ny-Alesund, Norway (2005-2006) and King George Island, Antarctica (2004-2005). Backward trajectories suggest that these stations are affected by long-range transport from source regions in Northern Europe and Russia and the southern tip of South America, respectively. Relatively high levels of PCB-11, averaging 60 pg x m(-3), were observed in Antarctica, suggesting an unusual source of PCB-11 to the Southern Hemisphere. Reflecting the hemispheric distribution of global PCB emissions, the average level of sigma205PCB (excluding three mono-CBs and PCB-11) was five times higher in the Arctic (95 pg x m(-3)) than in the Antarctic (19 pg x m(-3)). Levels of sigma9PCB at Ny-Alesund were similarto those reported for other Arctic sites, while levels at King George Island were lower than at other sites on the Antarctic Peninsula but 1 order of magnitude higher than background levels measured at a more remote Antarctic site. Light homologues were predominant in all samples (except for one Arctic sample), consistent with the hypothesis of global fractionation and predictions of long-range transport potential. Dominance of heavy PCBs on the roof of the main building at Ny-Alesund and a concentration gradient with distance from the main building at King George Island strongly indicated the influence of local sources. OCP levels were also influenced by long-range transport but not by local sources. This study highlights the feasibility of using passive air sampling to assess both long-range transport and local pollution in remote regions.

A comparative analysis of the bioaccumulation behaviour of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) was conducted involving simultaneous measurements of PBDE and PCB concentrations in organisms of a Canadian Arctic marine food web. Concentrations of individual PBDE congeners (BDE-28, -47, -99, -153, -154 and -183) in Arctic marine sediments (0.001-0.5 ng.g(-1) dry wt) and biota (0.1-30 ng.g(-1) wet wt) were low compared to those concentrations in biota from urbanized/industrial regions. While recalcitrant PCB congeners exhibited a high degree of biomagnification in this food web, PBDE congeners exhibited negligible biomagnification. Trophic magnification factors (TMFs) of PCBs ranged between 2.9 and 11, while TMFs of PBDEs ranged between 0.7 and 1.6. TMFs of several PBDE congeners (BDE-28, -66, -99, -100, -118, -153 and -154) were not statistically greater than 1, indicating a lack of food web magnification. BDE-47 was the only PBDE with a TMF (i.e. 1.6) statistically greater than 1, hence showing evidence of biomagnification in the food web. However, the TMF of BDE-47 (1.6) was substantially lower than TMFs of recalcitrant Cl(5)-Cl(7) PCBs (TMFs~9-11). Species-specific bioaccumulation factors (BAFs) of PBDEs in homeotherms were much smaller than those for PCBs. This further indicates the low degree or absence of biomagnification of PBDEs compared to PCBs in this food web. The field observations suggest PBDEs exhibit a relatively rapid rate of depuration though biotransformation in Arctic marine organisms, which is consistent with laboratory studies in fish and rats.

A sensitive magnetic particle enzyme-linked immunoassay (ELISA) was developed to analyze polybrominated diphenyl ethers (PBDEs) in water, milk, fish, and soil samples. The assay was rapid and can be used to analyze fifty samples in about 1h after sample cleanup. The assay has a limit of detection (LOD) below 0.1 ppb towards the following brominated diphenyl ether (BDE) congeners: BDE-47, BDE-99, BDE-28, BDE-100, and BDE-153, with the LOD approximately the same as GC-NCI-MS. The congeners most readily recognized in the ELISA were BDE-47 and BDE-99 with the cross-reactivities of BDE-28, BDE-100, and BDE-153 being less than 15% relative to BDE-47. As anticipated, the sensitivities are proportional to the similarities between the hapten structure and the BDE congener structure. Some oxygenated congeners with structural similarity to the hapten showed high to moderate cross-reactivities. Very low cross-reactivity was observed for other PBDEs or chlorinated environmental contaminants. The assay gave good recoveries of PBDEs from spiked water samples and a very small within and between day variance. Comparison with GC-NCI-MS demonstrated the ELISA method showed equivalent precision and sensitivity, with better recovery. The lower recovery of the GC-NCI-MS method could be caused by the use of an internal standard other than an isotopically substituted material that could not be used because of the fragmentation pattern observed by this method. The cleanup methods prior to ELISA were matrix dependent, no pretreatment was needed for environmental water samples, while fish, milk, and soil samples required various degrees of cleanup. Analysis of this wide variety of environmental samples by both ELISA and GC-MS demonstrated ELISA provides a timely and cost-effective method to screen for PBDEs in a variety of samples.

In vitro monitored estrogenicity of municipal wastewater influent/effluent samples (collected from September to December from a Northern Canadian biological nutrient removal (BNR) treatment plant serving an urban population of 750,000) were combined with operational, wastewater quality, and climate data to determine which of these latter variables may be related to the levels and reduction in the former parameter. Significant variability was present in operational and wastewater quality parameters throughout the sampling period including a 7 °C difference in wastewater temperature Most of the wastewater samples collected during this period show a considerable amount of recombinant yeast assay (RYA) activity with the greatest activity (estradiol (E2)-equivalents of 106–175 ng/L) seen in the final effluents collected from mid-September to mid-October. Percent reduction in the levels of RYA measured E2-equivalents varied from −234% to 75%. No correlations were seen in RYA activity reduction with percent reduction in 5-day biochemical oxygen demand (BOD 5 ), flow (i.e. inversely related to hydraulic retention time), solids retention time or even rainfall, and the reduction trends for RYA measured activity were explained best by ambient and effluent temperatures in an inverse fashion (% reduction in E2-equivalents=−10.8·(effluent temperature in °C)+191, p =0.005). Complementary instrumental analysis of select sample composites revealed that the free/conjugated estrogen ratio was indeed greater in the wastewater sampled during warmer temperatures.

Consumption of salmon, wild or farmed, has been encouraged by many scientists and by national and international health organizations due to the potential health benefits associated with their high contents of omega-3 (n-3) highly unsaturated fatty acids (n-3 HUFAs). In 2004, there was increased public concern regarding the safety of farmed Atlantic salmon following the publication of several studies that indicated higher levels of organohalogens in their flesh relative to those noted in the flesh of wild Pacific salmon. Farmed salmon obtain most of these contaminants from the consumption of marine fish oil (MFO) present in salmon feed. In both a laboratory feeding trial and an on-farm field study, partial replacement of MFO in aquaculture feeds with economical and abundant lipids of terrestrial origin resulted in farmed Atlantic salmon with reduced flesh polychlorinated biphenyl and polychlorinated dibenzodioxin and furan concentrations. Flesh levels of n-3 HUFAs (g/(100 g serving)) were lower in farmed Atlantic salmon fed diets with alternative lipids relative to farmed salmon fed more traditional MFO-based diets. However, the former salmon were found to have higher flesh levels of n-3 HUFAs and also similar or lower flesh levels of organic contaminants than some species of market-size wild Pacific salmon. These findings showthat consumption of either farmed Atlantic salmon or wild Pacific salmon can meet recommended weekly n-3 HUFA levels with minimal concurrent intake of flesh organohalogens.

Substances that accumulate to hazardous levels in living organisms pose environmental and human-health risks, which governments seek to reduce or eliminate. Regulatory authorities identify bioaccumulative substances as hydrophobic, fat-soluble chemicals having high octanol-water partition coefficients ( K OW )(≥100,000). Here we show that poorly metabolizable, moderately hydrophobic substances with a K OW between 100 and 100,000, which do not biomagnify (that is, increase in chemical concentration in organisms with increasing trophic level) in aquatic food webs, can biomagnify to a high degree in food webs containing air-breathing animals (including humans) because of their high octanol-air partition coefficient ( K OA ) and corresponding low rate of respiratory elimination to air. These low K OW –high K OA chemicals, representing a third of organic chemicals in commercial use, constitute an unidentified class of potentially bioaccumulative substances that require regulatory assessment to prevent possible ecosystem and human-health consequences.

Pacific sockeye salmon (Oncorhynchus nerka) can travel several hundred kilometers to reach native spawning grounds and fulfill semelparous reproduction. The dramatic changes in lipid reserves during upstream migration can greatly affect internal toxicokinetics of persistent organic pollutants (POPs) such as PCBs, PCDDs, and PCDFs. We measured lipid content changes and contaminant concentrations in tissues (liver, muscle, roe/gonads) and biomarker responses (ethoxyresorufin O-deethylase or EROD activity and CYP1A levels) in two Pacific sockeye salmon stocks sampled at several locations along their spawning migration in the Fraser River, British Columbia. Muscle lipid contents declined significantly with increasing upstream migration distance and corresponded to elevated lipid normalized concentrations of PCBs and PCDD/Fs in spawning sockeye. Post-migration magnification factors (MFs) in spawning sockeye ranged between 3 and 12 and were comparable to model-predicted MFs. sigmaPCBs(150-500 ng x g(-1) lipid), sigmaPCDD/Fs (1-1000 pg x g(-1) lipid) and 2,3,7,8-TCDD toxic equivalent or TEQ levels (0.1-15 pg x g(-1) lipid) in spawning sockeye were relatively low and did not affect hepatic EROD activity/CYP1A induction. Despite a 3-fold magnification, TEQ levels in eggs of spawning Fraser River sockeye did not exceed 0.3 pg x g(-1) wet wt, a threshold level associated with 30% egg mortality in salmonids. PCBs in Fraser River sockeye are comparable to previous levels in Pacific sockeye. In contrast to Pacific sockeye from more remote coastal locations, PCDDs and PCDFs in Fraser River sockeye were generally minor components (25%) of TEQ levels, compared to dioxin like PCB contributions (75%). The data suggest that (i) the Fraser River is not a major contamination source of PCBs or PCDD/Fs and (ii) marine contaminant distribution, food-chain dynamics, and ocean-migration pathway are likely important factors controlling levels and patterns of POPs in returning Pacific sockeye. We estimate an annual chemical flux entering the Fraser River of up to 150 g for sigmaPCBs and 40 mg for sigmaPCDD/ Fs via returning sockeye. The results indicate that historical concentrations of PCBs and PCDD/Fs remain a potential threat to organism and ecosystem health on the west coast of Canada.

A suite of 30 primarily estrogenic organic wastewater contaminants was measured in several influent/effluent wastewater samples from four municipal wastewater treatment plants and effluents from one bleached kraft pulp mill (BKME) using an ultra-trace analytical method based on gas chromatography-high resolution mass spectroscopy (GC-HRMS). In vitro recombinant yeast assay detection of the estrogenic equivalent (EEq) on whole and solid phase extracted (SPE) and fractionated wastewater was also performed. 19-norethindrone was the most frequently detected and abundant (26-224 ng/L) of all the synthetic estrogens/progesterones in the influent samples. 17alpha-ethinylestradiol was the more frequently detected synthetic estrogen/progesterone in the effluents occurring at or below 5 ng/L with some sporadic occurrences of up to 178 ng/L. The greatest levels of steroidal estrogens in municipal effluents were E1E2E3 which were all20 ng/L. Nonylphenol and di(2-ethylhexyl) phthalate were found to be the highest non-steroidal synthetic compounds surveyed in both municipal influent and effluent samples, both occurring at 6-7 microg/L in municipal effluents. BKME contained relatively large amounts of the plant sterol stigmasterol (4 microg/L) but low amounts of fecal sterols, and steroidal estrogens (E2 only at 6 ng/L) when compared to the municipal effluents. In vitro EEq in the wastewater surveyed ranged from 9-106 ng E2/L and ranked from municipal influentmunicipal effluent approximately BKME, with most of the estrogenicity fractionating in the 100% methanol SPE fraction followed by a secondary amount in the diethyl ether (for municipal) or methyl-tert butyl ether (for BKME) SPE fractions. Most correlations between chemical and in vitro estrogenic equivalency were weak (p0.05 in most cases). Unexpected inverse correlations between in vitro estrogenic activity and concentrations of the estrogenic contaminant bisphenol A were found which likely contributed to the weakness of these correlations. A modified toxicity identification and evaluation procedure was continued with the SPE extracts from the more potent 100% methanol SPE fractions of municipal effluent. High performance liquid chromatography band elution retention times, based on in vitro estrogen detection, indicated that steroidal estrogens such as E2 were responsible for most of the estrogenicity of the samples. Subsequent collection and GC-MS analysis of active bands did not confirm the presence of steroidal estrogens, but expanded the possibility of phthalate esters (i.e. dibutyl phthalate) and natural sterols (i.e. beta-sitosterol) contributing to the overall estrogenic load.

Optimization of the Varian Saturn 2200 ion-trap tandem mass spectrometry (IT-MS/MS) system and comparison of its data quality with two other detection methods [electron-capture detection (ECD) and high-resolution mass spectrometry (HRMS)] was pursued by measuring polychlorinated biphenyls (PCBs) levels in fish and shellfish samples. IT-MS/MS methodology provided limits of detection (LOD) comparable to those obtained by ECD but superior specificity for the detection of a selected number of 39 PCB native congeners and 9 13 C-labelled PCB standards. The method detection limits (MDLs) established for IT-MS/MS ranged between 1.0 and 5.0 pg/g on a wet weight basis while those obtained by ECD and HRMS were 1.0–4.0 pg/g and 0.1–2.0 pg/g, respectively. Overall, the results obtained in the study demonstrate that gas chromatography (GC) combined with IT-MS/MS provide higher data quality than those achievable by GC–ECD. For this particular set of target analytes the specificity achievable with IT-MS/MS was comparable to that obtained by HRMS and both techniques provided comparable data in terms of accuracy and precision.

This study compared the flesh quality of farmed and wild sources of British Columbia (BC) salmon with respect to concentrations of polychlorinated biphenyl compounds, polychlorinated dibenzodioxins/dibenzofurans and their associated toxic equivalents, total mercury (THg), methylmercury (MeHg), and selected fatty acids of known importance for human health viz., omega-3 (n-3) highly unsaturated fatty acids (n-3 HUFAs) and (n-6) fatty acids. Skinned fillets from known sources of farmed Atlantic, coho, and chinook salmon (n = 110) and wild coho, chinook, chum, sockeye, and pink salmon (n = 91) were examined. Atlantic salmon contained higher PCB concentrations (means, 28-38 ng/g) than farmed coho or chinook salmon, and levels in these latter species were similar to those in wild counterparts (means, 2.8-13.7 ng/g). PCB levels in Atlantic salmon flesh were, nevertheless, 53-71-fold less than the level of concern for human consumption of fish, i.e., 2000 ng/g as established by Health Canada and the U.S. Food and Drug Administration (US-FDA). Similarly, THg and MeHg levels in all samples were well below the Health Canada guideline (0.5 microg/g) and the US-FDA action level (1.0 microg/g). On average, THg in farmed salmon (0.021 microg/g) was similar to or lower than wild salmon (0.013-0.077 microg/g). Atlantic salmon were a richer source (mean, 2.34 g/100 g fillet) of n-3 HUFAs than the other farmed and wild sources of salmon examined (means, 0.39-1.17 g/100 g). The present findings support the recommended weekly consumption guidelines for oily fish species (includes all BC salmon sources) for cardio-protective benefits as made by the American Heart Association and the UK Food Standards Agency.

Due to a growing interest in the occurrence of pharmaceutically active compounds (PhACs) and endocrine disrupting compounds (EDCs) in the aquatic environment and their potential impacts on humans and the environment, a collaborative study was conducted on these emerging contaminants in the effluents from the wastewater treatment plants (WWTPs) and in the drinking water supply system of Calgary, Alberta. A number of PhACs and EDCs were detected in the WWTP effluents, at concentrations ranging from ng/L to low µ-g/L. Although these compounds were generally removed from WWTP effluents during wastewater treatment, some compounds, such as carbamazepine were more persistent. Some target PhACs and EDCs were detected at low ng/L levels in the surface and potable water in this study. Currently, there is no evidence that trace amounts of PhACs and EDCs in Calgary's waterways can have a health impact on humans, but they may pose adverse chronic effects on aquatic life.

Developing coho salmon alevin (Oncorhynchus kisutch) were exposed to concentrations of 1 to 10% municipal wastewater effluent (MWWE) during the labile period of sexual differentiation. MWWE was collected at regular time intervals from a municipal wastewater treatment plant during a 4-week period that coincided with the latter part of the spawning season of coho salmon. The salmon were exposed, from just prior to hatch until 28 d post hatch, to MWWE collected at 3 a.m., 8 a.m., 3 p.m. or 8 p.m. Subsequent gonadal development was assessed by histology and compared to genetic sex as determined by Y-chromosomal DNA markers. The MWWE (analyzed using GC-HRMS) had relatively high concentrations of steroidal estrogens and other endocrine active substances at some time points during the exposure period. A low incidence of intersex and sex reversal was noted in the coho salmon exposed to MWWE collected at only two time points; 3 a.m. (1% MWWE) and 8 p.m. (10% MWWE), and ≤19% of the male fish in these exposure groups were affected. The coho salmon utilized were of wild genetic backgrounds and thus the sporadic nature of the response observed may be due to a significant genetic influence on the ability to respond to exogenous hormones at this early stage of development.