東華大學圖書館 |

Microplastics' Journey Into The Gut : = Human Exposure To Microplastics And Associated Chemicals.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Microplastics' Journey Into The Gut :/
其他題名:	Human Exposure To Microplastics And Associated Chemicals.
作者:	Mohamed Nor, Nur Hazimah Bte.
面頁冊數:	1 online resource (166 pages)
附註:	Source: Dissertations Abstracts International, Volume: 84-01, Section: B.
Contained By:	Dissertations Abstracts International84-01B.
標題:	Triglycerides. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29185639click for full text (PQDT)
ISBN:	9798835552962

Microplastics' Journey Into The Gut : = Human Exposure To Microplastics And Associated Chemicals.
Mohamed Nor, Nur Hazimah Bte.

Microplastics' Journey Into The Gut :Human Exposure To Microplastics And Associated Chemicals. - 1 online resource (166 pages)

Source: Dissertations Abstracts International, Volume: 84-01, Section: B.

Thesis (Ph.D.)--Wageningen University and Research, 2022.

Includes bibliographical references

Microplastics are small plastic particles (1‒5000 µm), which are omnipresent in the environment and may likely be ingested by biota, especially humans. There has been an increasing concern on how much microplastics humans are actually exposed to in the world and if the levels can actually cause any effect in us. One of the potential effects of microplastics that have been identified is its ability to transport chemicals into the organism (commonly referred to as the vector effect) when the particles are ingested. Therefore, the fundamental aim of this thesis was to unravel the lifetime exposure of microplastics in humans around the world and the extent of the role of microplastics as a vector for chemical bioaccumulation in humans and other biota. To accomplish these aims, a mechanistic approach was needed that involved developing sophisticated experimental methods, mechanistic models, and modeling tools. The primary focus of this thesis was the transport of microplastics through the gastrointestinal tract and the extent of the chemical vector effect during the gut retention time.This thesis started with understanding the chemical dynamics of microplastics in a simulated gut environment using an in vitro experimental approach. A series of experimental setups to represent three different environmentally relevant scenarios was examined. First, an organism ingests contaminated (i.e., associated with chemicals) microplastics. Second, an organism ingests contaminated microplastics and contaminated food. Third, an organism ingests clean microplastics and contaminated food. Chemical transfer was demonstrated to be biphasic and fully reversible on the microplastics, with fast exchange within hours followed by a slow transfer lasting for weeks to months. Therefore, a biphasic reversible chemical exchange model was constructed and parameterized for organic chemicals on microplastics with the in vitro experimental data. Low density polyethylene (LDPE) showed faster sorption kinetics than polyvinyl chloride (PVC). Additionally, the apparent affinity of chemicals with PVC decreases as chemical hydrophobicity increases, which is contrasting to that found for LDPE. Model parameters from this first study was also later used in a later part of this thesis to understand the chemical vector effect in humans. Overall, this study demonstrated that whether microplastics increase or decrease the chemical body burden of an organism is context dependent.Although the first study in this thesis had provided a fundamental understanding on the chemical dynamics of microplastic-associated organic chemicals in the gut fluid systems, the food component in the experimental setup was an inert pool. In reality, food is constantly digested in the gastrointestinal tract of the biota, which would affect the chemical dynamics.Therefore, a follow-up in vitro gut fluid study was designed to include the food digestion kinetics and further develop the earlier biphasic reversible chemical exchange model. At the same time, the chemical affinities for different gut components (olive oil lipids and micelles) were investigated to evaluate the relative chemical distribution for each component. Our findings showed that as the olive oil lipids were digested by the enzyme, lipase, food-associated chemicals were released and taken up by microplastics. This process would decrease the amount of chemicals available for uptake by the organism when the microplastics are egested.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798835552962Subjects--Topical Terms:

3221269
Triglycerides.
Index Terms--Genre/Form:

542853
Electronic books.

Microplastics' Journey Into The Gut : = Human Exposure To Microplastics And Associated Chemicals.
LDR:04854nmm a2200397K 4500 001 2363117
005 20231116093757.5
006 m o d
007 cr mn ---uuuuu
008 241011s2022 xx obm 000 0 eng d
020 $a 9798835552962
035 $a (MiAaPQ)AAI29185639
035 $a (MiAaPQ)Wageningen594785
035 $a AAI29185639
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Mohamed Nor, Nur Hazimah Bte. $3 3703864
245 1 0 $a Microplastics' Journey Into The Gut : $b Human Exposure To Microplastics And Associated Chemicals.
264 0 $c 2022
300 $a 1 online resource (166 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 84-01, Section: B.
500 $a Advisor: Koelmans, A. A.
502 $a Thesis (Ph.D.)--Wageningen University and Research, 2022.
504 $a Includes bibliographical references
520 $a Microplastics are small plastic particles (1‒5000 µm), which are omnipresent in the environment and may likely be ingested by biota, especially humans. There has been an increasing concern on how much microplastics humans are actually exposed to in the world and if the levels can actually cause any effect in us. One of the potential effects of microplastics that have been identified is its ability to transport chemicals into the organism (commonly referred to as the vector effect) when the particles are ingested. Therefore, the fundamental aim of this thesis was to unravel the lifetime exposure of microplastics in humans around the world and the extent of the role of microplastics as a vector for chemical bioaccumulation in humans and other biota. To accomplish these aims, a mechanistic approach was needed that involved developing sophisticated experimental methods, mechanistic models, and modeling tools. The primary focus of this thesis was the transport of microplastics through the gastrointestinal tract and the extent of the chemical vector effect during the gut retention time.This thesis started with understanding the chemical dynamics of microplastics in a simulated gut environment using an in vitro experimental approach. A series of experimental setups to represent three different environmentally relevant scenarios was examined. First, an organism ingests contaminated (i.e., associated with chemicals) microplastics. Second, an organism ingests contaminated microplastics and contaminated food. Third, an organism ingests clean microplastics and contaminated food. Chemical transfer was demonstrated to be biphasic and fully reversible on the microplastics, with fast exchange within hours followed by a slow transfer lasting for weeks to months. Therefore, a biphasic reversible chemical exchange model was constructed and parameterized for organic chemicals on microplastics with the in vitro experimental data. Low density polyethylene (LDPE) showed faster sorption kinetics than polyvinyl chloride (PVC). Additionally, the apparent affinity of chemicals with PVC decreases as chemical hydrophobicity increases, which is contrasting to that found for LDPE. Model parameters from this first study was also later used in a later part of this thesis to understand the chemical vector effect in humans. Overall, this study demonstrated that whether microplastics increase or decrease the chemical body burden of an organism is context dependent.Although the first study in this thesis had provided a fundamental understanding on the chemical dynamics of microplastic-associated organic chemicals in the gut fluid systems, the food component in the experimental setup was an inert pool. In reality, food is constantly digested in the gastrointestinal tract of the biota, which would affect the chemical dynamics.Therefore, a follow-up in vitro gut fluid study was designed to include the food digestion kinetics and further develop the earlier biphasic reversible chemical exchange model. At the same time, the chemical affinities for different gut components (olive oil lipids and micelles) were investigated to evaluate the relative chemical distribution for each component. Our findings showed that as the olive oil lipids were digested by the enzyme, lipase, food-associated chemicals were released and taken up by microplastics. This process would decrease the amount of chemicals available for uptake by the organism when the microplastics are egested.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Triglycerides. $3 3221269
650 4 $a Organic chemicals. $3 3560375
650 4 $a Polyvinyl chloride. $3 686187
650 4 $a Bioaccumulation. $3 1071297
650 4 $a Food contamination & poisoning. $3 3562624
650 4 $a Equilibrium. $3 668417
650 4 $a Sediments. $3 3566210
650 4 $a Bisphenol A. $3 3377853
650 4 $a Chemical contaminants. $3 3695529
650 4 $a Polychlorinated biphenyls--PCB. $3 3680680
650 4 $a Polycyclic aromatic hydrocarbons. $3 697430
650 4 $a Bioavailability. $3 875104
650 4 $a Low density polyethylenes. $3 3695272
650 4 $a Polymers. $3 535398
650 4 $a Polyethylene. $3 2014375
650 4 $a Soil sciences. $3 2122699
650 4 $a Sodium. $3 3562677
650 4 $a Kinetics. $3 717752
650 4 $a Beverages. $3 548730
650 4 $a Natural & organic foods. $3 3564674
650 4 $a Agronomy. $3 2122783
650 4 $a Food science. $3 3173303
650 4 $a Physics. $3 516296
650 4 $a Plastics. $3 649803
650 4 $a Polymer chemistry. $3 3173488
650 4 $a Sedimentary geology. $3 3173828
655 7 $a Electronic books. $2 lcsh $3 542853
690 $a 0481
690 $a 0285
690 $a 0359
690 $a 0605
690 $a 0795
690 $a 0495
690 $a 0594
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a Wageningen University and Research. $3 3557914
773 0 $t Dissertations Abstracts International $g 84-01B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29185639 $z click for full text (PQDT)