Spatial Distribution, Air-Water Exchange, and Toxicity of Organic Pollutants Using Passive Samplers
Notice bibliographique
Résumé
Thousands of hydrophobic organic contaminants (HOCs) are present in air and water worldwide, yet we know little about how these chemicals’ concentrations vary spatially and temporally, or what biological effects they have in concert. The first four studies described in this dissertation present data from a sampling campaign in which passive polyethylene samplers (PEs) deployed throughout the lower Great Lakes region (Lake Erie and Lake Ontario) from 2011 to 2014. Results were used to deduce air-water fluxes and analyze spatial trends of the truly gaseous and dissolved fraction of three distinct groups of HOCs: polycyclic aromatic hydrocarbons (PAHs), polycyclic musks (PCMs), and organic flame retardants (OFRs), with the goal of better understanding how sources and physico-chemical properties determine the environmental transport and spatial distribution of these HOCs. The specific objectives of these studies were to determine whether gaseous and dissolved HOCs exhibited positive correlation with regional population density within 25 km of each site in the lower Great Lakes region, investigate whether diffusive air-water exchange of HOCs was primarily leading to volatilization from, or absorption into, the lakes’ surface waters, and investigate health risks of ambient urban air by measuring aromatic hydrocarbon receptor (AhR)-mediated potency of the truly gaseous mixture of HOCs accumulated in PEs deployed in air on the Lake Erie shoreline near Cleveland (OH). Results showed that the radius at which strongest correlation between gaseous HOC concentration and human population was observed depended on vapor pressure, and a relationship between the maximum distance where significant correlation occurred and compound vapor pressure is presented for amassed PAH, PBDE, and PCM data. Air-water exchange calculations based on simultaneously deployed air and water PEs indicated that diffusive exchange of PAHs was variable based on compound and season. PCMs were found to be volatilizing from the lakes’ surface waters, suggesting that Lake Erie and Lake Ontario were acting as secondary sources of PCMs, while PBDEs were absorbed into surface waters. Bioassay experiments performed on PE extracts showed that <30% of AhR-mediated potency for gaseous air extracts was explained by target compounds measured via chemical analysis, suggesting that targeted analysis may underestimate health risks posed by gas-phase ambient air. The fifth and sixth studies described in this dissertation focused on measuring uptake of emerging and legacy HOCs into PEs to inform future calculation of ambient air and water concentrations from PE measurements. PE uptake profiles over 21-day deployments were used to determine whether
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 | 0,000 | 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) | 0,000 | 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 ».