Analysis of Metal Contaminants and Mercury Speciation in Fishes from the Slave and Athabasca Rivers
Notice bibliographique
Résumé
The Slave and Athabasca are two connected rivers impacted by a variety of anthropogenic activities such as oil sands extraction, metal mining, pulp mills and agriculture. Concerns have been raised regarding the health of these two rivers especially the Athabasca River which runs through areas of oil sands development. The health of fish in these rivers is one of the primary concerns due to the cultural and economic importance of the fish to local community members. Metal contaminants in fish can have an impact on fish health and can pose a risk to the health of consumers of fish, including humans. This thesis investigates metals in five fish species (burbot, goldeye, northern pike, walleye, and whitefish) from sites along the Slave and Athabasca Rivers during four seasons (summer, fall, winter, and spring). A suite of 25 metals were analyzed by ICP-MS and the majority of the metal concentrations showed little location associated variability nor were they detected at concentrations of concern. One metal, Hg, was detected at concentrations of concern and four metals (As, Se, Tl, and V) demonstrated statistically significant variations in concentrations between sampling sites with greater concentrations in the sites on the lower Slave River compared to the upper Slave River, Athabasca River, and Peace River sites. The concentrations of these metals were not of sufficient magnitude to be of concern to fish or human health, but the trend is of interest due to concerns regarding industrial activities on the Athabasca River. Mean Hg concentrations in fish muscle exceed Health Canada consumption guidelines in 2.6% of fish groups separated by species, location, and season. These concentrations exceeded subsistence advisory Hg guideline concentrations in 47.4% of fish groups. The magnitude of Hg concentrations was not new information as other researchers have found similar concentrations in fish in the region and fish consumption advisories are already in place for the Athabasca River due to Hg concerns. The two species of Hg found in fish are Hg(II) and methylmercury. Methylmercury is the predominant form of Hg in fish and has the potential to biomagnify, increasing concern for fish and human health. A method to analyze for the two Hg species was developed utilizing sodium tetraethylborate derivatization with headspace solid-phased microextraction (SPME) followed by gas chromatography and orbitrap mass spectrometry (GC-Orbitrap MS) analysis. The use of GC-Orbitrap MS allows for the scanning of a wide range of mass/charge (m/z) at high resolution (>200,000). This resolution and scan range were utilized to quantify each Hg species and Hg isotopes. The percent of total Hg represented by methylmercury in a subsample of the fish collected from the Slave and Athabasca Rivers were found to be 82.4% for goldeye, 90.2% in northern pike, 87.2% in walleye, 92.3% in whitefish, and 87.5% in burbot. Isotope patterns of Hg were also determined for these samples though the method was not sensitive enough to detect subtle differences in stable isotope patterns. Mercury concentrations are nearing, and in certain circumstances exceeding, Canadian guidelines. Overall, metal concentrations, with the exception of Hg, in the Slave and Athabasca Rivers do not appear to be at levels of concern for fish or human health at this time. The trend of four metals being greater in the lower Slave River provides an interesting opportunity for further research into metal chemodynamics.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| 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 | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| 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) | 0,001 | 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 source (Gemma direct ou Codex distillé), 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 ».