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Georgetown, Canada

Kennedy C.J.,Simon Fraser University | Stecko P.,Minnow Environmental | Truelson B.,Environment Canada | Petkovich D.,Access Consulting Group
Environmental Toxicology and Chemistry | Year: 2012

The modulation of Cu effects on olfactory-mediated behaviors by dissolved organic carbon (DOC) and Fe was examined in juvenile chinook salmon. Chinook were exposed to several concentrations of Cu, DOC, and Fe alone or in combination in a flow-through system for either 4 d (acute exposure) or 14 d (subchronic exposure) and tested for their ability to detect and avoid the odorant L-histidine in an avoidance/preference trough assay. In both acute and subchronic exposures, Cu inhibited the ability of fish to detect this amino acid in a concentration-dependent manner, and Cu toxicity (olfactory inhibition) decreased with increasing DOC concentration. In both acute and subchronic experiments including DOC, Cu-induced olfactory inhibition decreased in a linear fashion with increasing DOC concentration, although the modulation was lower in subchronic exposures. The protective effect of DOC on Cu olfactory inhibition was reduced only slightly in the presence of Fe, indicating that other metals can potentially affect the modulation of the olfactory inhibition of Cu through competition for DOC binding sites. The results of the present study clearly show the amelioration by DOC of the effects of Cu on juvenile chinook salmon olfaction at a behavioral level. These data further indicate that DOC concentrations should be considered when evaluating the potential impact of Cu on fish olfaction. © 2012 SETAC.

Orr P.L.,Minnow Environmental | Wiramanaden C.I.E.,Minnow Environmental | Paine M.D.,Paine | Franklin W.,Teck Coal Ltd. | Fraser C.,Teck Coal Ltd.
Environmental Toxicology and Chemistry | Year: 2012

Previous studies conducted in the Elk River watershed showed that selenium concentrations are higher in aquatic biota in lentic compared to lotic habitats of the system having similar water selenium concentrations. Studies have also shown that water selenium concentrations have increased over time (~10% per year) and recent annual average concentrations have ranged up to 0.044mg/L in areas downstream from mine discharges. For the present study, trophic transfer of selenium was characterized in lotic versus lentic habitats using concentrations measured in field-collected samples and assuming a three-step food chain of water to the base of the food web (biofilm), to benthic invertebrates, and then to westslope cutthroat trout (WCT) ovaries. Food chain models were developed for each habitat type (lotic and lentic) by combining linear regression equations for the three transfer relationships, allowing for prediction of fish ovary concentrations from water concentrations. Greater accumulation of selenium in lentic areas was mostly attributable to greater uptake at the base of the food chain compared to lotic areas. Enrichment/trophic transfer factors for selenium at all levels of the lotic and lentic food chains decreased and then became near constant as exposure concentrations increased. The lotic model predicted little increase in WCT ovary selenium concentrations over an eightfold increase in water concentrations (~0.005-0.040mg/L), accounting for the lack of observed increase in within-area fish tissue concentrations over time despite increasing trends in water concentrations. © 2011 SETAC.

Janz D.M.,University of Saskatchewan | Liber K.,University of Saskatchewan | Pickering I.J.,University of Saskatchewan | Wiramanaden C.I.E.,Minnow Environmental | And 12 more authors.
Integrated Environmental Assessment and Management | Year: 2014

For the past decade, considerable research has been conducted at a series of small lakes receiving treated liquid effluent containing elevated selenium (Se) from the Key Lake uranium (U) milling operation in northern Saskatchewan, Canada. Several studies related to this site, including field collections of water, sediment, and biota (biofilm and/or periphyton, invertebrates, fish, and birds), semicontrolled mesocosm and in situ caging studies, and controlled laboratory experiments have recently been published. The aim of the present investigation was to compile the site-specific information obtained from this multidisciplinary research into an integrative perspective regarding the influence of Se speciation on biogeochemical cycling and food web transfer of Se in coldwater ecosystems. Within lakes, approximately 50% of sediment Se was in the form of elemental Se, although this ranged from 0% to 81% among samples. This spatial variation in elemental Se was positively correlated with finer particles (less sand) and percent total organic C content in sediments. Other Se species detected in sediments included selenosulfides, selenite, and inorganic metal selenides. In contrast, the major Se form in sediment-associated biofilm and/or periphyton was an organoselenium species modeled as selenomethionine (SeMet), illustrating the critical importance of this matrix in biotransformation of inorganic Se to organoselenium compounds and subsequent trophic transfer to benthic invertebrates at the base of the food web. Detritus displayed a Se speciation profile intermediate between sediment and biofilm, with both elemental Se and SeMet present. In benthic detritivore (chironomid) larvae and emergent adults, and in foraging and predatory fishes, SeMet was the dominant Se species. The proportion of total Se present as a SeMet-like species displayed a direct nonlinear relationship with increasing whole-body Se in invertebrates and fishes, plateauing at approximately 70% to 80% of total Se as a SeMet-like species. In fish collected from reference lakes, a selenocystine-like species was the major Se species detected. Similar Se speciation profiles were observed using 21-day mesocosm and in situ caging studies with native small-bodied fishes, illustrating the efficient bioaccumulation of Se and use of these semicontrolled approaches for future research. A simplified conceptual model illustrating changes in Se speciation through abiotic and biotic components of lakes was developed, which is likely applicable to a wide range of northern industrial sites receiving elevated Se loading into aquatic ecosystems. Key Points: Selenium speciation profiles were determined in biotic and abiotic compartments (whole sediments, detritus, periphyton and/or biofilm, benthic invertebrates, emergent insects, forage fish, and predatory fish) of a coldwater aquatic ecosystem using synchrotron-based X-ray absorption spectroscopy (XAS) Integrating the results of 10 previously published articles, this case study provides broader perspectives on the influence of Se speciation on biogeochemical cycling and food web transfer of Se in northern coldwater aquatic ecosystems Periphyton and/or biofilm at the sediment-water interface was the key driver of Se biotransformation to organoselenium species and subsequent trophic transfer to benthic invertebrates and fishes In benthic invertebrates and fishes, Se speciation profiles shifted from selenocystine-like species to selenomethionine-like species in a concentration-dependent manner, plateauing at approximately 70% to 80% of total Se as selenomethionine-like species © 2014 SETAC.

Wiramanaden C.I.E.,Minnow Environmental | Orr P.L.,Minnow Environmental | Russel C.K.,Minnow Environmental
Environmental Toxicology and Chemistry | Year: 2015

The present study investigated the integrated effects of several geochemical processes that control radium-226 (226Ra) mobility in the aquatic environment and bioaccumulation in in situ caged benthic invertebrates. Radium-226 bioaccumulation from sediment and water was evaluated using caged oligochaetes (Lumbriculus variegatus) deployed for 10d in 6 areas downstream of decommissioned uranium operations in Ontario and Saskatchewan, Canada. Measured 226Ra radioactivity levels in the retrieved oligochaetes did not relate directly to water and sediment exposure levels. Other environmental factors that may influence 226Ra bioavailability in sediment and water were investigated. The strongest mitigating influence on 226Ra bioaccumulation factors was sediment barium concentration, with elevated barium (Ba) levels being related to use of barium chloride in effluent treatment for removing 226Ra through barite formation. Observations from the present study also indicated that 226Ra bioavailability was influenced by dissolved organic carbon in water, and by gypsum, carbonate minerals, and iron oxyhydroxides in sediment, suggestive of sorption processes. Environmental factors that appeared to increase 226Ra bioaccumulation were the presence of other group (II) ions in water (likely competing for binding sites on organic carbon molecules), and the presence of K-feldspars in sediment, which likely act as a dynamic repository for 226Ra where weak ion exchange can occur. In addition to influencing bioavailability to sediment biota, secondary minerals such as gypsum, carbonate minerals, and iron oxyhydroxides likely help mitigate 226Ra release into overlying water after the dissolution of sedimentary barite. Environ Toxicol Chem 2015;34:507-517. © 2015 SETAC.

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