Freshwater Effects of Pesticide Mixtures in Mesocosms of Great Pond Snails (Lymnaea stagnalis)
Notice bibliographique
Résumé
Pesticide exposure in the environment accumulates through soil, water, and living organisms. Environmental factors such as weather and water conditions can influence how pesticides can impact an ecosystem. Pesticide mixtures from agricultural runoffs could have complex interactive effects between compounds on organisms in natural waterways. Toxicity of pesticides can be increased through additive or synergistic effects in a mixture. This study assessed the chronic toxicity of a pesticide mixture on the great pond snails (Lymnaea stagnalis) over a 28-day period using semi-natural outdoor mesocosms. We used the mesocosms to house a natural biofilm (periphyton) that included other small invertebrates. This design incorporates trophic exposure of pesticides, and potential community effects of the pesticides on the food web. L. stagnalis is a model organism in ecotoxicology. It has well-studied growth, reproductive, behavioral, and biochemical responses to anthropogenic stress that we utilized for this study. We chose to expose the snails and biofilm to a pesticide mixture commonly found in the water surrounding corn/soybean farming of southern Quebec, Canada, based on a report by the ministère de l’Environnement et de la Lutte contre les changements climatiques de la Faune et des Parcs (MELCCFP). Our final selection included the herbicides atrazine, metolachlor, and glyphosate, as well as the insecticides clothianidin, thiamethoxam, imidacloprid, and chlorantraniliprole. The pesticide mixture varied at three environmentally relevant concentrations (atrazine: 0.5-5 ng/mL; metolachlor: 1-10 ng/mL; glyphosate: 1.5-15 ng/mL; clothianidin, imidacloprid, thiamethoxam, chlorantraniliprole: 0.05-0.5 ng/mL). We showcased physiological effects with respect to nominal reductions in pesticide mixture concentrations. We also confirmed environmental exposure concentrations in the experimental media and tissues to provide evidence for policy makers and agronomists to make decisions about the future of agricultural practices. Results showed that snail survival rates were unaffected by pesticides. Smaller snails had lower survival at the highest mixture concentration compared to larger snails, leading to a larger increase in the remaining 1x mixture treatment population’s average body mass. This increase in body mass could potentially be due to community effects, as shown in other studies. The effect sizes of changes in population body mass did decrease with reduced pesticide mixture concentrations. Clutch sizes increased in 1x treatments at greater rates compared to controls. However, 0.5x treatments exhibited reduced clutch sizes compared to controls. Stress-induced reproduction of L. stagnalis has been observed in other studies. However, it was unclear if the varied reproductive effects are a gradient of toxicity with respect to the pesticide exposure concentration. Snail tissues had higher amounts of s-metolachlor, chlorantraniliprole, glyphosate, and imidacloprid than the water, indicating bioaccumulation. Biofilm tissue bioconcentrated chlorantraniliprole, s-metolachlor, and glyphosate at larger than the water. Concentrations of herbicides (atrazine, s-metolachlor, and glyphosate) in snails was significantly related to the concentrations in biofilm, suggesting possible trophic transfer. A two-fold reduction in pesticide exposure did not reduce the accumulation factors of s-metolachlor and imidacloprid in pond snails. Likewise, the concentration factors of s-metolachlor and chlorantraniliprole in biofilm were not diminished. In conclusion, pesticide mixture effects are complex, with imposed sub-lethal and community effects that can appear to benefit an organism. The costs of body mass or reproduction changes need to be studied further. Additionally, the threat of pesticide bioaccumulation in snails and its potential to move throughout the food web remains an unanswered concern.
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 ».