Impact of the COVID-19 pandemic on Montreal municipal wastewater leading to increase exposure to endocrine disruptor nanoparticles: potential effect on placental biology
Bibliographic record
Abstract
The COVID-19 pandemic brought about a sudden change in behavior, leading to increased exposure to harmful compounds derived from single-use plastics, and environmental impacts whose effects may be felt for generations. To this end, we analyzed Montreal municipal wastewater data for levels of suspended solids and oxidizing species. Our analyses show that human activity in times of sanitary restriction leads to a temporary reduction in wastewater contamination. In the second part of this study, we focused on metal nanoparticles as emerging compounds linked to single-use plastics. Specifically, we focused on titanium dioxide, zinc oxide and cerium dioxide. We tested their effects on JEG-3 choriocarcinoma cells (placental cell model). First, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cell viability assays were used to determine the IC50 concentration of each of the nanoparticles analyzed. We subsequently performed flow cytometry and immunofluorescence analyses to determine the apoptotic state and condition of cell nuclei, respectively. Our results show that all nanoparticles reduce cell viability and increase apoptosis. The greatest effects were observed with zinc oxide, which showed an IC50 of 153.2 and 146.5 ug/ml at 24hr and 48hr exposure respectively. Overall, our results indicate that nanoparticles have a deleterious effect on the viability and proliferation of JEG-3 cells, a placental cell model, suggesting a potential effect of these three nanoparticles on pregnancy and fetal development. Further studies on primary placental cell cultures are required to confirm and extend these findings. La pandémie de COVID-19 a entraîné un changement soudain des comportements qui a conduit à une exposition accrue aux composés nocifs dérivés des plastiques à usage unique ainsi qu'à des impacts environnementaux dont les effets peuvent se faire sentir pendant des générations. À cette fin, nous avons analysé les données relatives aux eaux usées municipales de Montréal pour déterminer les niveaux de matières en suspension ainsi que les espèces oxydantes. Nos analysent démontrent que l'activité humaine en temps de restriction sanitaire entraîne une réduction temporaire de la contamination des eaux usées. Dans la seconde partie de cette étude nous nous sommes concentrés sur les nanoparticules métalliques en tant que composés émergents liés aux plastiques non réutilisables. Plus particulièrement, nous nous sommes concentrés sur le dioxyde de titane, l'oxyde de zinc et le dioxyde de cérium. Nous avons testé leurs effets sur les cellules de choriocarcinome JEG-3 (modèle de cellules placentaires). Dans un premier temps, les tests de viabilité cellulaire MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) ont été effectués pour déterminer la concentration IC50 de chacune des nanoparticules analysées. Nous avons par la suite effectué des analyses de cytométrie en flux et d’immunofluorescence, pour déterminer l’état apoptotique et la condition des noyaux des cellules, respectivement. Nos résultats montrent que toutes les nanoparticules réduisent la viabilité cellulaire et augmentent l'apoptose. Les effets les plus importantes ont été observé avec le ZnO, qui montrent un IC50 de 153.2 et 146.5 ug/ml à 24hr et 48hr d’exposition respectivement. Dans l’ensemble, nos résultats indiquent que les nanoparticules ont un effet délétère sur la viabilité et la prolifération des cellules JEG-3, un modèle de cellules placentaires, suggérant un effet potentiel de ces trois nanoparticules sur la grossesse et le développement du foetus. D'autres études devront être menées sur les cultures cellulaires placentaires primaires pour confirmer et approfondir ces résultats.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".