Evaluation of the diffusion gradient in thin-films (DGT) technique for measuring trace metal concentrations in freshwaters
Notice bibliographique
Résumé
The recently developed Diffusion Gradient in Thin-films (DGT) technique is based on a simple device that accumulates metals in situ, over time in a Na resin gel. Metal ions diffuse through a hydrogel membrane and are rapidly bound by the resin. The many advantages associated with the DGT technique (simplicity, in situ technique, low detection limits, and ability to measure many metals) have lead to its rapid application in aquatic environments. Caveats have been recognized with the DGT technique when it is used in aquatic environments. These include: the ability of strongly complexed organic-metal molecules to diffuse through the hydrogel and become complexed by the resin gel, and in freshwater lakes with a low concentration of cations (Σ [cations] ≤ 2 × 10 -4 M), it is hypothesized that the diffusion coefficient of metal ions entering the DGT device increases. Both of these caveats overestimate the concentrations of labile inorganic metals in the deployment solution. The hypothesis that deploying DGT devices equipped with two different hydrogel formulations ("open" and "tight") will provide reasonable measurements of DGT-labile "organic" and "inorganic" concentrations of Mn, Cd and Pb was tested in the field. DGT devices were deployed in three lakes (Lake Tantare, Lake 8t. Joseph and Lake Memphremagog). To compare the responses of the DGT devices with the total dissolved metal concentration (< 0.20 um) of each lake, in situ dialysis samplers were deployed simultaneously. Overestimation of DGT-labile "inorganic" concentrations of Mn and Pb, and overestimation of DGT-labile "organic" Cd was observed when compared to the measured total dissolved metal concentrations in the lakes. The hypothesis that DGT devices equipped with a Ca form of the resin gel (as an alternative to the sodium based resin gel in the DGT device) will reasonably measure Mn, Cd and Pb labile metal concentrations in freshwater lakes with low cation concentrations was tested. DGT devices with the Ca form of the resin gel were deployed in Lake Tantare, Lake 8t. Joseph and Lake Memphremagog. Overestimation of DGT-labile metal concentrations of Mn, Cd and Pb were observed with the Ca resin gel in the lakes when compared to the measured total dissolved concentrations. The implication of these findings is that the DGT technique should not be used in freshwaters with low cation concentrations (Σ [cations] ≤ 2 × 10 -4 M), typical of lakes found in the Canadian environment, until the caveats of the technique have been resolved. Extreme caution should be used when drawing conclusions regarding the concentrations of inorganic and organic metal species, since it has been found the DGT devices with the two different hydrogel formulations overestimate the inorganic metal concentration relative to the organic metal concentration in aquatic environments.
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 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 | 0,004 | 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 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 ».