Accumulation of mercury and selenium in the brain of river otters (Lontra canadensis) and wild mink (Mustela vison) from Nova Scotia, Canada

Haines, Kevin J.R.; Evans, R. Douglas; O'Brien, Michael; Evans, Hayla E.

doi:10.1016/j.scitotenv.2009.09.055

Cited by 35 publications

(20 citation statements)

References 35 publications

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“…A previous study [14] also detected greater Hg in otters trapped further from the coast. Possibly, Hg that reaches high concentrations in terrestrial waters becomes diluted by oceanic [29] found no correlation between Hg concentrations and corpora lutea scars in wild otters (each scar represents a past birth).…”

Section: Discussionmentioning

confidence: 51%

“…Additional factors that may decouple fur Hg and reproductive effects include demethylation and shunting to fur. Several studies have suggested that MeHg may be demethylated (and thus detoxified) in the liver of waterbirds, and although this may occur in otters, the mechanisms are not well understood [7,14,32,33].…”

Section: Discussionmentioning

confidence: 99%

“…Fur samples were removed from feet of carcasses and sent to Trent University (Peterborough, Ontario, Canada) for total Hg quantification. Methylmercury is strongly correlated with total Hg [14] and highly correlated among tissues [7]. Fur samples were washed prior to analysis.…”

Section: Methodsmentioning

confidence: 99%

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Correlates of mercury in female river otters (Lontra canadensis) from Nova Scotia, Canada

Spencer

Shutler

O'Brien

2011

Enviro Toxic and Chemistry

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Mercury (Hg) can reach toxic concentrations in aquatic habitats, sometimes as a consequence of human activity. Mercury can have deleterious effects, particularly in piscivorous mammals in which it bioaccumulates. Furs from trapper-provided female otter (Lontra canadensis) carcasses in Nova Scotia were analyzed for total Hg. Concentrations of total Hg in fur samples averaged 25 µg/g dry weight, ranging from 1.4 to 137 µg/g; 20 µg/g is the fur concentration at which toxic effects are expected. Mercury concentrations were greater in otters from watersheds with bedrock substrates known to contain more available Hg, from otters trapped farther inland, and from otters trapped on watersheds with hydroelectric dams. Otter reproductive potential was measured by counting the number of blastocysts in reproductive tracts. Tooth annuli were used to age otters. Reproductive potential was not related to Hg concentration, nor was Hg concentration related to age. In a general linear model, 53% of variation in fur Hg was explained by underlying bedrock, distance from the coast at which otters were trapped, and presence/absence of a hydroelectric dam. The proportion of juveniles in a population did not differ relative to bedrock Hg concentration, but was lower on watersheds with hydroelectric dams. Because we found no evidence of reduced reproductive potential from greater Hg concentrations, the low proportion of juveniles suggests that Hg reduced juvenile survival, although our evidence is circumstantial.

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Section: Discussionmentioning

confidence: 51%

Section: Discussionmentioning

confidence: 99%

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Correlates of mercury in female river otters (Lontra canadensis) from Nova Scotia, Canada

Spencer

Shutler

O'Brien

2011

Enviro Toxic and Chemistry

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“…In addition, differences across species may lead to increased understanding of unique sensitivities and molecular mechanisms. As mentioned earlier, studies have shown mammalian wildlife to differ in their ability to metabolize methylmercury in their brain tissues (Basu et al 2005a, b ;Haines et al 2010 ) .…”

Section: Health Effects Of Methylmercurymentioning

confidence: 93%

“…For example, mink and river otters are both members of the Mustelidae family and inhabit common environments, but they have vastly different abilities to metabolize mercury. Mink have a poorer ability to demethylate organic mercury (~80 vs. >95% of total mercury was organic) and accumulate selenium (which is believed to counteract the neurotoxicity of MeHg) in a 1:1 molar ratio in their brain when compared to river otter (Basu et al 2005a, b ;Haines et al 2010 ) . While there is ample evidence that mink are sensitive to mercury, much less evidence exists for otters.…”

Section: Environmental Exposures To Methylmercurymentioning

confidence: 99%

Piscivorous Mammalian Wildlife as Sentinels of Methylmercury Exposure and Neurotoxicity in Humans

Basu

2012

Methylmercury and Neurotoxicity

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The purpose of this chapter is to provide an overview of how piscivorous (fi sh-eating) wildlife can be used to complement existing public health strategies to assess the neurotoxic risks of methylmercury. A brief introduction concerning the use of wildlife as model sentinel organisms in the fi eld of environmental neurotoxicology is provided. Next, selected scientifi c examples are detailed that illustrate how data from piscivorous wildlife may provide pertinent, real-world information on the bioavailability of methylmercury and environmental exposures. Information concerning methylmercury's subclinical (e.g., perturbations in brain neurochemistry and neuroendocrine hormones) and clinical (structural and functional defi cits) neurological effects across organisms is also discussed.

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Ecogenetics of mercury: From genetic polymorphisms and epigenetics to risk assessment and decision‐making

Basu

Goodrich

Head

2014

Enviro Toxic and Chemistry

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The risk assessment of mercury (Hg), in both humans and wildlife, is made challenging by great variability in exposure and health effects. Although disease risk arises following complex interactions between genetic ("nature") and environmental ("nurture") factors, most Hg studies thus far have focused solely on environmental factors. In recent years, ecogenetic-based studies have emerged and have started to document genetic and epigenetic factors that may indeed influence the toxicokinetics or toxicodynamics of Hg. The present study reviews these studies and discusses their utility in terms of Hg risk assessment, management, and policy and offers perspectives on fruitful areas for future research. In brief, epidemiological studies on populations exposed to inorganic Hg (e.g., dentists and miners) or methylmercury (e.g., fish consumers) are showing that polymorphisms in a number of environmentally responsive genes can explain variations in Hg biomarker values and health outcomes. Studies on mammals (wildlife, humans, rodents) are showing Hg exposures to be related to epigenetic marks such as DNA methylation. Such findings are beginning to increase understanding of the mechanisms of action of Hg, and in doing so they may help identify candidate biomarkers and pinpoint susceptible groups or life stages. Furthermore, they may help refine uncertainty factors and thus lead to more accurate risk assessments and improved decision-making.

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Accumulation of mercury and selenium in the brain of river otters (Lontra canadensis) and wild mink (Mustela vison) from Nova Scotia, Canada

Cited by 35 publications

References 35 publications

Correlates of mercury in female river otters (Lontra canadensis) from Nova Scotia, Canada

Correlates of mercury in female river otters (Lontra canadensis) from Nova Scotia, Canada

Piscivorous Mammalian Wildlife as Sentinels of Methylmercury Exposure and Neurotoxicity in Humans

Ecogenetics of mercury: From genetic polymorphisms and epigenetics to risk assessment and decision‐making

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