Microplastics as Contaminant Vectors: Influencing the Bioaccessibility of Naphthalene from Freshwater

dc.contributor.authorAvazzadeh Samani, Farhaden
dc.contributor.departmentChemical Engineeringen
dc.contributor.supervisorMeunier, Louise Jr
dc.date.accessioned2023-05-25T18:55:48Z
dc.date.available2023-05-25T18:55:48Z
dc.degree.grantorQueen's University at Kingstonen
dc.description.abstractMicroplastics (MPs) are found throughout the environment and pose risks to human health as particulate pollutants. In addition, they have the potential to transfer environmental contaminants to humans and other sensitive receptors. However, there is a paucity of information on the vector effects of MPs for toxic persistent organic pollutants (POPs) in freshwater systems. The purpose of this research was to investigate the capacity of MPs to transfer naphthalene, a carcinogenic polycyclic aromatic hydrocarbon (PAHs), from freshwater systems to the human gastrointestinal tract (GIT). The focus was on characterizing the sorption mechanisms of naphthalene and its bioaccessibility (i.e., an estimate of the fraction of an ingested dose that becomes soluble in gastro-intestinal fluids). Three types of MPs, medium-density polyethylene (MDPE), polypropylene (PP), and polystyrene (PS), were selected as model compounds. The sorption behaviour of naphthalene onto these MPs was investigated through the kinetic and isotherm experiments in freshwater, and the bioaccessible fraction of naphthalene in the gastric and intestinal digestive phases was measured using a modified physiologically based extraction test (PBET). The effects of aging of MPs on the sorption of naphthalene was also investigated. The sorption kinetics of naphthalene onto MPs followed a pseudo second order model, with external mass transport as the rate-controlling step. Sorption was dominated by a hydrophobic interaction mechanism, as indicated by Langmuir and linear isotherm models. The sorption capacity of naphthalene followed the decreasing order of MDPE > PP > PS. The bioaccessibility of naphthalene was higher in the intestinal phase (28 to 60%) than in the gastric phase (24 to 40%). Artificial aging altered MP physico-chemical characteristics, with the sorption capacity of naphthalene decreasing by 25% for MDPE and increasing by 35% and 26% for PP and PS, respectively. These findings demonstrate that MPs can act as potential carriers for the transfer of POPs from freshwater environments to the human body. Consequently, MPs may provide a pathway (i.e., a vector effect) for human exposure to contaminants and pose a risk to human health. Further studies are necessary to assess the vector effect and risks of MPs for transferring other POPs in freshwater.en
dc.description.degreeM.A.Sc.en
dc.embargo.liftdate2028-05-24T19:33:10Z
dc.embargo.termsI am in the process of preparing the third chapter of my thesis for submission to a scientific journal, and it is currently in its final revision stage. In order to safeguard the rights for commercial publication and to ensure there are no plagiarism issues affecting the forthcoming publication, I respectfully request to restrict the availability of my thesis. I believe that this precautionary measure is in the best interest of preserving the academic integrity and commercial viability of our work.en
dc.identifier.urihttp://hdl.handle.net/1974/31670
dc.language.isoengen
dc.relation.ispartofseriesCanadian thesesen
dc.rightsQueen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canadaen
dc.rightsProQuest PhD and Master's Theses International Dissemination Agreementen
dc.rightsIntellectual Property Guidelines at Queen's Universityen
dc.rightsCopying and Preserving Your Thesisen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.subjectVector effecten
dc.subjectAssociated contaminantsen
dc.subjectHuman healthen
dc.subjectRisk assessmenten
dc.subjectContaminant transporten
dc.subjectIncidental ingestionen
dc.subjectIn-vitro digestion modelen
dc.subjectMicroplasticsen
dc.subjectArtificial agingen
dc.subjectSorptionen
dc.subjectBioaccessibilityen
dc.subjectMicroplastic ingestionen
dc.subjectpolycyclic aromatic hydrocarbonsen
dc.titleMicroplastics as Contaminant Vectors: Influencing the Bioaccessibility of Naphthalene from Freshwateren
dc.typethesisen
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