Persistence of glyphosate, and associated influence on available nutrients, in native plant tissues following sublethal herbicide application in northern British Columbia forests
Notice bibliographique
Résumé
Glyphosate-based herbicides (GBH) are highly effective, nonselective herbicides that have been used in British Columbia’s forest industry since the early 1980s to remove deciduous vegetation competing with commercially important coniferous tree seedlings. Long term persistence of glyphosate and its metabolic byproduct aminomethylphosphonic acid (AMPA) in the forest ecosystem has not previously been monitored beyond one year, although it is known that glyphosate may be stored in tissues of plants that received a sublethal dose of GBH. The primary objective of this research thesis was to determine the duration (up to twelve years) of glyphosate and AMPA persistence in the roots, shoots, and fruits of selected perennial plant species in GBH-treated forest cutblocks. Due to the ability of glyphosate to form insoluble complexes with metal ions, it was suspected that metal nutrient concentrations in surviving plants might be affected by persistent glyphosate. The second main objective of this thesis was to determine if concentrations of calcium (Ca), iron (Fe), magnesium (Mg), manganese (Mn), nickel (Ni) and zinc (Zn) were significantly altered by GBH treatment. Plant tissue samples from five forest understory perennial species growing in two distinct biogeoclimatic (BEC) zones of northern BC were analyzed for glyphosate and AMPA content, and comparisons were made between species, plant tissue type, and BEC zone. Residues persisted for up to 12 years in some tissue types, and root tissues generally retained glyphosate residues longer than shoot tissue types. Samples from the drier, colder, more northern Boreal White and Black Spruce (BWBS) BEC zone retained significantly higher levels of glyphosate for longer than samples collected from the warmer Sub-Boreal Spruce (SBS) BEC zone. Shoot samples from three species in the SBS zone were further analyzed for nutrient contents. Nutrient concentrations were more variable over time in treated samples than in control samples, and comparison of treated and control samples resulted in significant differences in 47 % of all cases, and in 61 % of year one samples. Generally, Ca, Mg and Ni decreased with treatment in all three species; Zn increased with treatment for each species; and Fe and Mn had inconsistent changes with treatment. Both the persistence of glyphosate and related changes in plant nutrient concentrations may have cumulative health effects for wildlife. More research should be conducted in this field, as many questions remain unanswered.
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 | 0,001 | 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 ».