Toxicity of surface water and pore water from an oil sands pit lake (Lake Miwasin) to Daphnia
Notice bibliographique
Résumé
Canada holds approximately one-third of the world's confirmed crude oil reserves, primarily concentrated in the Alberta Oil Sands (AOS) region, in the form of bitumen. However, the extraction process of oil sands generates significant volumes of tailings and process water, which raises concerns about their potential effects on aquatic life and the need for remediation. Lake Miwasin, constructed in 2018, serves as a pilot-scale pit lake and a model for this context. It features treated fluid tailings overlaid by a mixture of oil sands process-affected water (OSPW) and freshwater, exhibiting seasonal stratification. Since its establishment, Lake Miwasin has been colonized by various organisms, including the Crustacean, Daphnia pulex. Monitoring data from Lake Miwasin has shown the presence of compounds in both water and sediment that could be detrimental to aquatic organisms. Therefore, the primary goals of this research were to assess surface water and pore water toxicity, including an evaluation of selenium (Se) bioaccumulation in Daphnia species exposed to the conditions representative of Lake Miwasin at its early development stages and possibly other future pit lakes in the AOS region.\nThis study examined the toxicity of Lake Miwasin surface water (LMW) and pore water (LMP) using lab-cultured and native Daphnia species. Interestingly, LMW exhibited no acute or chronic toxicity towards D. magna and D. pulex (lab strains) and the native Daphnia sp. (collected from Humboldt Lake, SK, Canada). However, LMP demonstrated acute toxicity to both lab strains and the native D. pulex (collected from Lake Miwasin, AB, Canada). Lake Miwasin pore water also negatively impacted lab D. pulex reproduction, leading to a reduced number of offspring. Salinity emerged as a significant stressor in LMP, and a Toxicity Identification Evaluation (TIE) phase I suggested ammonia and metals in LMP as potential contributors to the observed toxicity in the tested organisms. On a related point, results showed that concentrations of dissolved Se in LMW from 2019 to 2021 exceeded the Canadian Council of Ministers of Environment (CCME) water quality guidelines for long-term aquatic life protection (1 µg/L), and the British Columbia Ministry of Environment (BC MoE) water guideline alert concentration for the protection of aquatic life (1 µg/L). The latter water guideline was also adopted by the Government of Alberta. Further, another experiment assessed Se bioaccumulation in D. pulex through dissolved and dietary exposure routes, drawing comparisons to native specimens collected from Lake Miwasin. In semi-static tests (12 days), lab strain D. pulex exposed to selenate [Se(VI)] showed a Se concentration-dependent increase from days 5 to 12 for most treatments, whereas a lower bioaccumulation occurred at higher Se concentrations, which suggests a potentially internal regulatory mechanism. Native D. pulex exposed to LMW in laboratory conditions showed that Se bioaccumulation levels were similar to those of D. pulex collected directly from Lake Miwasin. Despite these findings, the Se concentrations in D. pulex from both lab exposures and Lake Miwasin collections remained below available regulatory guidelines for invertebrate tissue (4 µg/g), suggesting that D. pulex appears to pose minimal risk as a food source in the Lake Miwasin ecosystem. \nThese findings provide useful insights into the toxicity of Lake Miwasin water to aquatic invertebrates, the potential for Se bioaccumulation in daphnids in Lake Miwasin, the potential enhancement of pit lake monitoring programs, and the decision-making regarding the use of end pit lakes in the reclamation of OSPW and oil sands tailings.
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 | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 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 ».