Trapped river otters (Lontra canadensis) from central Saskatchewan exhibit differences in total and organic mercury concentrations with sex and geographic location
Notice bibliographique
Résumé
Human activities have resulted in increasing amounts of mercury Hg(II) in the atmosphere, oceans, and terrestrial systems. Biological processes convert inorganic forms of mercury released into the atmosphere into the neurotoxic and bioaccumulating methylmercury (MeHg) species resulting in increased concern for Hg emissions entering the biosphere. Once deposited from the atmosphere, in-situ methylation of inorganic Hg in sediments is believed to be the largest source of MeHg to freshwater aquatic systems compared to input from the terrestrial environment (i.e. run-off) or atmospheric deposition. Methylation of Hg is predominantly a microbial mediated process that is facilitated by some sulfate and iron reducing bacteria, as well as methanogens. Biological activity, nutrient availability, pH, temperature, redox potential, and the presence of inorganic and organic complexing agents have significant effects on rates of methylation. Degradation of MeHg can occur as well, so that the amount of MeHg available to organisms is a result of two opposing processes. Mink (Mustela vison) and otter (Lontra canadensis) are the most studied mammalian wildlife species with regard to Hg exposure and toxicity. Data indicate that consumption of diets that contained Hg (as MeHg) >1 mg kg-1 wet weight can cause neurotoxicity and death in adult mink and otter. Neurological signs in MeHg-intoxicated mammals typically include lethargy, ataxia, limb paralysis, tremors, convulsions, and ultimately death. Here, I measured Hg concentrations in fur, liver and kidney tissues removed from river otters (Lontra canadensis) collected from trappers in central Saskatchewan (n = 203) over two trapping seasons. Total Hg (THg) concentrations measured in otter tissues were consistent with tissues measured in other non-impacted sites in Canada. Fur THg was positively correlated with total and organic Hg measured in liver and kidney tissue, highlighting the potential for using fur as a rapid and less expensive method of monitoring Hg in mammals. Livers from males had significantly higher mean organic Hg concentrations than livers of females (p = 0.015), however, no sex related differences were observed in kidney organic Hg concentrations. Total Hg concentrations in the fur of otters collected in the Churchill River Upland (Boreal Shield ecozone) was significantly higher (p < 0.001) than otters collected from all other ecoregions located in the Boreal Plain ecozone. Otters trapped in close proximity to the now decommissioned smelter located in Flin Flon, MB contained the highest concentrations of total Hg measured in my study.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».