Chapter 1 gives a general introduction into plastic polymer and microplastics including concepts, sources and distribution in the environment, microplastic sampling and analytical methods, and sampling area descriptions. Chapter 2 represents all methods and followed equipment used in the thesis. A double-filtration procedure preferable to Raman microscopy technique was developed to collect marine microplastics in brackish water from Can Gio and seawater from the East Sea. Chapter 3 is a comprehensive guideline on IR and Raman spectra interpretation of PE, PP, PVC, PS, PMMA, and polymer textiles, which is especially useful if the automatic library is not available. This chapter represents how to identify polymer type, predict sources and chemical behaviours of microplastics with the smallest size of 15 μm based on microscopic and spectroscopic data. Also, this chapter evaluates the sample handling workflows for salt, water and sand samples. Chapter 4 demonstrates the change in microplastic pollution from 250 MPs/L in Saigon urban canals (the center of Ho Chi Minh City), through UNESCO Can Gio Mangrove Biosphere Reserve (10 – 20 MPs/L), to estuaries of Saigon-Đong Nai River, Soai Rap River, Long Tau River (Ganh Rai Gulf), and eventually to the East Sea (3 – 5 MPs/L). Chapter 5 highlights the correlation of microplastic properties and compositions in beach sand and seawater in the coastal environment, particularly at Can Gio 30 April Tourist Beach. This is a pilot study to identify the differences and similarities in morphologies and compositions of microplastics accumulated in beach sand and distributed in seawater, thereby, concluding sources and transport routes of microplastics in the coastal environment. The results show that microplastics accumulated at concentrations from 0 to 92.56 MPs/kg from the surface to 20-cm sand layers. The seawater at Can Gio Beach and Đong Tranh Cape contained 6.44 and 3.75 MPs/L of microplastics, respectively. White polyethylene fragments predominated, and all the microplastics comprised small secondary microplastics with a minimum size of 25 µm and a maximum size of 260 µm for fragments and a length of 640 µm for fibers. The proportions of PE, PP, PS and PMMA were similar. The differing percentages of other compositions in sand and seawater are attributed to the morphology and density of the microplastics. Chapter 6 deals with the detection and determination of microplastics in Vietnamese sea salts. As a result, there was a higher fluctuation in microplastic amount amongs non-branded salts compared with branded salts. An average of 133.62 MPs/kg salt, corresponding to 487.71 microplastics entering the human body per year via salt consumption. More importantly, this chapter provides a convincing evidence for microplastic contamination in marine salts from the seawater. There are similarities in percentage, shape, size and colour of microplastics, especially PE, PET and PP extracted from sea salt and seawater collected in 3 different regions in Southern Vietnam (Can Gio Reserve and Vung Tau).:Chapter 1. Introduction 1.1. Synthetic polymers and plastic products 1.1.1. Overview of polymers and plastics 1.1.2. Plastic applications and global productions 1.1.2.1. Conventional plastics 1.1.2.2. Bioplastics 1.1.3. The life cycle of plastics and plastic pollution 1.2. Microplastics – definitions, sources and fate 1.2.1. Definition and classification of microplastics 1.2.2. Sources and pathways of microplastics into the environments 1.2.3. Global distribution and behaviours of microplastics in the environment 1.2.3.1. Physical behaviours: temporal and spatial accumulations 1.2.3.2. Chemical behaviours: Degradation and Adsorption 1.2.3.3. Biobehaviours: Ingestion, Translocation and Biodegradation 1.3. Effects and bioavailability of plastics on ecosystems, creatures and humans 1.3.1. Aquatic ecosystem 1.3.2. Terrestrial ecosystem 1.3.3. Food safety and human healths 1.4. Microplastic sampling techniques and analytical methods 1.4.1. Microplastic sampling techniques 1.4.1.1. Water sampling 1.4.1.2. Sediment sampling 1.4.2. Sample preparations for microplastic analysis 1.4.2.1. Matrix removal – oxidation and tissue digestion 1.4.2.2. Microplastic separation – density flotation and filtration 1.4.3. Microplastic qualification and quantification methods 1.4.3.1. Visual identification methods 1.4.3.2. Spectroscopic identification methods 1.4.3.3. Destructive thermal techniques 1.4.3.4. Summarized workflow from samples to the results on microplastics 1.4.3.5. Data expression Chapter 2. Materials and Methods 2.1. Materials 2.2. Microscopy-spectroscopy for microplastic quantification and qualification 2.3. Quality assurances (QA) and quality controls (QC) 2.4. Collected and interviewed data on the study areas 2.5. Water samples 2.6. Sand samples 2.7. Marine salt samples Chapter 3. The comprehensive guideline on micro-spectroscopic interpretation and sample preparations for microplastic analysis 3.1. Abstract 3.2. Visual characterizations of microplastics 3.3. Interpretation of IR and Raman spectra for plastic identification 3.4. The specificity of spectroscopies for identifying polymer type and chemical behaviours of sampled microplastics 3.4.1. Poly-Ethylene (PE) 3.4.2. Poly-Propylene (PP) 3.4.3. Poly-Vinyl Chloride (PVC) 3.4.4. Poly-Styrene (PS) 3.4.5. Poly Methyl Metacrylate (PMMA) 3.4.6. Poly-Ethylene Terephthalate (PET) 3.4.7. Poly-Amides-6, Nylon-6 (PA-6) 3.4.8. Similarity in Raman bands of pure plastics and sampled microplastics 3.5. The evaluation of sample treatment procedures 3.5.1. Salt samples 3.5.2. Sand samples 3.5.3. Water samples Chapter 4. Assessing microplastic prevalence and spatial dispersion from Saigon urban river network to East Sea by µ-Raman spectroscopy 4.1. Abstract 4.2. Microplastic pollution in the freshwater at Saigon urban canals 4.3. Microplastic pollution in the seawater at Can Gio Biosphere Reserve 4.4. Spatial and vertical dispersion of microplastics in the East Sea of Vietnam 4.5. Conclusions Chapter 5. Comparison of Microplastic Pollution in Beach Sediment and Seawater at UNESCO Can Gio Mangrove Biosphere Reserve 5.1. Abstract 5.2. Microplastic pollution in the sand at Can Gio Beach 5.2.1. Spatial variation in the microplastic amounts along the tidal lines 5.2.2. The abundance and composition of microplastics accumulated in sand layers 5.3. Microplastic pollution in seawater at Can Gio Beach and Đong Tranh Cape 5.4. Comparison of microplastic pollution between seawater and beach sand 5.5. Conclusions and recommendations Chapter 6. Microplastic contamination in Vietnamese sea salts 6.1. Abstract 6.2. The microplastics abundance in commercial sea salts 6.3. Microplastic pollution in the seawater taken at salt pans in Vietnam 6.4. Microplastic contamination in the sea salt collected at salt pans in Vietnam 6.5. Comparison of characteristics of microplastics in the seawater and sea salt 6.6. The enhanced toxicity of microplastics-contaminated salt consumption 6.7. Conclusions and recommendations Final Conclusions and Future Recommendations List of references Appendix Statistical data Photos taken on the sampling trips

This thesis presents a cross-national, cross-regime examination of foreign policy decision-making in the Spratly Islands dispute, focusing on China, Malaysia and the Philippines. It argues that how and why these countries have acted in particular ways towards the dispute relates to the relationship among foreign policy decision-making, government behaviour and domestic politics. The theoretical foundation of the study is foreign policy analysis. It applies the decision units approach advanced by Margaret and Charles Hermann and Joe Hagan to investigate who made foreign policy decisions on the Spratly Islands dispute in the three countries during the period 1991-2002, and how this influenced government behaviour. In addition, the contextual influence of domestic politics is considered. Four case studies inform the empirical analysis: the approaches taken by Malaysia and the Philippines to bolster their respective sovereignty claim, China???s establishment of a comprehensive maritime jurisdictional regime covering the Spratly Islands among other areas, China-Philippines contestation over Mischief Reef and the development of a regional instrument to regulate conduct in the South China Sea. Three conclusions are drawn. First, the decision units approach identifies the pivotal foreign policy decision-makers in each of the countries examined and the process involved. Second, it explains the relationship between decision unit characteristics -- self-contained or externally influenceable -- and each government???s behaviour towards the dispute. Injecting domestic politics into the analysis highlights motivations of and constraints faced by decision-makers, conditioning the form and content of government action. Third, it demonstrates a low predictive capability: the ???fit??? between hypothesised and actual government behaviour is poor. While it is not a comprehensive analytical tool, the combined decision units-domestic politics approach offers deeper insight into government decisions and behaviour on the Spratly Islands dispute than hitherto reported in the literature.

This thesis presents a cross-national, cross-regime examination of foreign policy decision-making in the Spratly Islands dispute, focusing on China, Malaysia and the Philippines. It argues that how and why these countries have acted in particular ways towards the dispute relates to the relationship among foreign policy decision-making, government behaviour and domestic politics. The theoretical foundation of the study is foreign policy analysis. It applies the decision units approach advanced by Margaret and Charles Hermann and Joe Hagan to investigate who made foreign policy decisions on the Spratly Islands dispute in the three countries during the period 1991-2002, and how this influenced government behaviour. In addition, the contextual influence of domestic politics is considered. Four case studies inform the empirical analysis: the approaches taken by Malaysia and the Philippines to bolster their respective sovereignty claim, China???s establishment of a comprehensive maritime jurisdictional regime covering the Spratly Islands among other areas, China-Philippines contestation over Mischief Reef and the development of a regional instrument to regulate conduct in the South China Sea. Three conclusions are drawn. First, the decision units approach identifies the pivotal foreign policy decision-makers in each of the countries examined and the process involved. Second, it explains the relationship between decision unit characteristics -- self-contained or externally influenceable -- and each government???s behaviour towards the dispute. Injecting domestic politics into the analysis highlights motivations of and constraints faced by decision-makers, conditioning the form and content of government action. Third, it demonstrates a low predictive capability: the ???fit??? between hypothesised and actual government behaviour is poor. While it is not a comprehensive analytical tool, the combined decision units-domestic politics approach offers deeper insight into government decisions and behaviour on the Spratly Islands dispute than hitherto reported in the literature.

2013年3月14日，習近平成為中共的最高領導人，不同於前幾代中國大陸領導人，習近平提出了「中國夢」的願景，不僅為主導與型塑著習近平時代中共的對外政策、戰略規劃與全球佈局，且其的內涵伴隨著情勢發展和現實需要不斷的擴充，不僅積極應處周邊關係，穩定亞太地區、妥善處理海權爭議、牽制美國亞太「再平衡」戰略，並向西推進「一帶一路」戰略。 而在亞太地區被公認為世界經濟發動的火車頭之際，「重返亞洲」則成美國最重要的外交目標。歐巴馬政府重新調整外交政策，強調透過盟友、國際制度、謹慎的外交及道德理想的力量來爭取他人認同美國的目標，藉此促進本身的利益；同時，藉由增加在該地區的政治、經濟和軍事投入，逐漸提升其他國家對於美國的信任，藉此鞏固美國的領導地位。 美中雙方為何這麼在意在南海區域的發展及權利伸張，美國在仲裁案後特別強調南海是美國「最高國家利益」，而中方也早早就說過南海是中國的「核心利益」，如此是否註定中美兩方必在南海地區發生權力爭奪戲碼，不禁令人要問美、中雙方到底誰才是破壞南海和平或南海秩序的國家？ 南海究竟具備什麼樣的地理特性或其他重要的條件，讓世界的霸權及崛起的強權交集的南海地區，而使這個地區被學者示警南海恐成第3次世界大戰舞臺。 / On March 14, 2013, Xi Jinping became the supreme leader of the Chinese Communist Party. Unlike the leaders of the previous generation of mainland China, Xi Jinping put forward the vision of "Chinese Dream", not only for the foreign policy and strategic planning And the global layout, and its connotation along with the development of the situation and the reality needs to continue to expand, not only actively should be peripheral relations, stability in the Asia-Pacific region, properly handle the sea dispute, contain the US Asia-Pacific "rebalancing" strategy, and westward " Along the way "strategy. In the Asia-Pacific region is recognized as the world economy launched the locomotive, the "return to Asia" has become the United States the most important diplomatic goals. The Obama administration has reoriented its foreign policy by emphasizing the goal of the United States through its allies, international regimes, prudent diplomatic and moral ideals, to promote its own interests; by increasing the political, Economic and military investment, and gradually enhance the confidence of other countries for the United States, to consolidate the US leadership. Why the United States and China are concerned about the development of the South China Sea region and the right to extend the United States in the arbitration case, especially stressed that the South China Sea is the United States "the highest national interest", and the Chinese side has long said that the South China Sea is China's "core interests", so destined China and the United States will be in the South China Sea area of power to compete for drama, can not help but to ask the United States, the two sides in the end who is the destruction of the South China Sea peace or the South China Sea order of the country? The South China Sea has what kind of geographical features or other important conditions, so that the world's hegemony and the rise of the power of the intersection of the South China Sea region, leaving the region by the students to warn the South China Sea fear of the third World War stage.

正如古典現實主義者所提倡的，最初的政治學中的關係探究存在於人類的本質中。權力的交替定義了君主世界中的相對關係，也因而形塑了我們對利益的追求。這樣的權力轉變正在中國發生，同時這也反應在中國對南海戰略的政策上。古典現實主義提供了海洋的國際政治學一個嶄新觀點。透過地理政治學上的解釋性分析，此研究檢視中國的政策與對世界的影響。在南海，中國持續崛起的力量、戰略與政策導致由中國主導的區域秩序。本研究所採用的研究方法發現到，中國崛起是一股相對的力量，且美國所企圖採取的權力平衡，可能無法成功圍堵中國的崛起。 / The primordial causal relationship within politics lies in the condition of our human nature, as classical realists argue. The constant exchange in power defines the relative relationships within the anarchical world, and shapes our pursuit of interests thereof. Such a change in power is occurring within China, and this is being reflected on its shifting policy and conduct in the South China Sea. Classical realism ought to shed light on and put forth a new perspective on the situation in the maritime sphere of international politics. The thesis scrutinizes, through interpretive analysis within a geopolitical approach, China’s policy and how it sees the world. The outcome of China’s increasing power, strategy and subsequent policy results in a China-led regional order starting in the waters of the South China Sea. The importance of this method in seeing China’s rise is the relativity of power and how the balance of power, including US, may prove to be inconclusive in trying to contain China’s unprecedented rise.

本文最主要的目的有二。其一為評估「民主和平論」是否依然有效地解釋「戰爭與和平」議題。若然，那麼同為自由主義的「貿易和平」是否相較之下之解釋力較佳。第二則是個案研究，聚焦於「南海爭端」用以進一步驗證本文的論述。本文認為以制度層面而言，貿易量事實上相較於政治體制是較能降低衝突帶來和平。 / This thesis has two purposes: the first one is to re-examine “Democratic Peace” and to testify “Trade Peace” with an eye to finding a more explainable solution on the issue of Conflict and Peace; and the second purpose is by providing a case study centering on the region of the South China Sea, the premise of this thesis will further be evaluated. The premise in here is that from an institutional perspective, trade is the more efficient and less costly method to reduce the possibility of initiating armed conflicts than polities.

Sovereignty over the South China Sea waters and the territorial features therein has been a contentious issue since at least the 1970’s, with conflicting claims going back even further. Key concepts of Liberal and Neo-Realist International Relations Theory are used to assess respective theory’s explanatory capability for why the South China Sea Dispute is difficult to settle. The scope of the study is limited to three pairings of international relations: China-Philippines, China-Vietnam and China-USA. The analysis concerns the development of these sets of international relations from 2016 up until now. The findings point to unilateral action by one claimant in the face of contesting claims by another as being one of the main factors perpetuating the conflict. Treaties and international law are designed with Liberal development of international relations in mind, but in practice Neo-Realist hard power politics interrupts this development. Examples of disruptive action include attempts to unilaterally exploit natural resources in the region, settling features in the sea, doing construction work on features in the sea, as well as regular FONOPS conducted by navy ships in the region. Finally, there are difficulties settling on a mechanism for sovereignty settlement, as China makes its claims based on historic- or historical claims, rather than international law as it is written out in UNCLOS.

The overall purpose of this dissertation is to provide an empirical study of the post-Cold War EastAsian security setting, with the aim of understanding why there is an East Asian peace. The EastAsian peace exists in a region with a history of militarised conflicts, home to many of the world'slongest ongoing militarised problems and a number of unresolved critical flashpoints. Thus, thepost-Cold War East Asian inter-state peace is a paradox. Despite being a region predicted to be ripefor conflict, there have not only been less wars than expected, but the region also shows severalsigns of a development towards a more durable peace. The dominant research paradigm –neorealism – has painted a gloomy picture of post-Cold War East Asia, with perpetual conflictsdominating the predictions. Other mainstream international relations theories, too, fail to accountfully for the relative peace. One of the greatest problems for mainstream theories, is accounting forpeace given East Asia's lack of security organisations or other formalised conflict managementmechanisms. Given this paradox/problem, this dissertation sets out to ask "Why is there a relativepeace in the East Asian security setting despite an absence of security organisations or otherformalised mechanisms to prevent existing conflicts from escalating into violence?" In order to answer this question, the case of East Asian peace is approached by comparingthree embedded case studies within the region: the Taiwan issue, the South China Sea, and theKorean nuclear conflict. It explores the full range of informal and formal processes plus the ConflictPrevention and Peacebuilding Mechanisms (CPPBMs) that have been important for the creation ofa continuing relative peace in East Asia between 1990 and 2008. The study furthermore focuses onChina's role in the three cases, on an empirical basis consisting of interviews conducted with keypersons during more than 1.5 years fieldwork in China. The three cases show that informal processes exist, and that they have furthermore beenimportant for peace, both by preventing conflicts from escalating into war, and by buildingconditions for a stable longer-term peace. Their impact on the persistence of peace has been tracedto a range of different CPPBMs. Returning to the level of the East Asian case, a common feature ofmany of the identified processes is that they can be understood as aspects or manifestations of theEast Asian regionalisation process. Specifically, elite interactions (personal networks, track twodiplomacy), back-channel negotiations, economic interdependence and integration, and functionalcooperation have together with (China's acceptance of) multilateralism and institutionalisation (ofpeaceful relations) been of high importance for the relative peace. Whereas formalised conflictmanagement mechanisms and the U.S. presence have also contributed to peace, this dissertationshows their contribution to be much more limited.

南海爭端近幾年區域緊張情勢不斷升高。中國已將南海列為「核心利益」，而美國則將南海視為「國家利益」。基此，這顯現中美兩國在南海議題的積極作為，雙方在其處理南海議題的戰略架構下，兩國主要舉措均在外交與軍事層面上針鋒相對。外交上中國以「睦鄰外交」，穩定周邊局勢，美國則運用「前沿部署外交」拉攏東亞各國；兩國對於東協國家的態度將更為重視，亦是雙方外交戰略的重點所在，渠等均希望藉由東協國家的支持在南海議題上更有話語權。而軍事上中國以「反介入/區域拒止」的軍事作為防止域外國家介入其主權議題，而美國研擬「空海一體戰」除運用其強大的軍事科技實力外，欲結合各盟邦的力量，與其一同牽制中國的軍事行動。 綜上，在中美兩國相互的競逐作為下，佐以米爾斯海默之攻勢現實主義觀點，檢視中美兩國在南海之未來互動關係。潛在霸權國中國擁有眾多的人口與快速成長的經濟，並在南海整軍經武，試圖強化與東協甚或是東亞諸國的經貿互賴程度，且於處理亞洲事務中將美國排除在外，以取代美國擔任亞洲關鍵角色，尤其在南海的不妥協性，顯現出中國在此區域的主導性。另外，既存霸權國美國面對中國綜合國力崛起，則扮演「離岸平衡者」，融合「推諉卸責」、「均勢」之概念，拉攏東協及日本、印度等相關國家，共同制衡南海區域的權力失衡狀態，鞏固霸權地位。中美雙方皆將南海問題的層級提高，並且均欲爭取南海區域之領導地位，因此兩國在此區域未來將趨於競爭關係。 / The tension caused by the South China Sea dispute has been rising in recent years. China has listed the South China Sea as her “core interest”, while the U.S. considers the South China Sea as “national interest”. This, shows that both China and the U.S. have been acting aggressively on the South China Sea issue. Both sides, under their own strategic frames in dealing with the issues, square off over each other’s diplomatic and military acts. Diplomatically, China practices “Good Neighboring Diplomacy” to stabilize the relations with her surrounding neighbors, while the U.S. applies “Forward-Deployed Diplomacy” to bring together each country in East Asia to fight against China. The two countries value the attitude of the ASEAN members more than ever, and this is also the main focus of their diplomatic strategies; both desire to have more say on the South China Sea issue by gaining support from members of the ASEAN. In terms of military operation, China practices “Anti-Access/Area-Denial” to prevent other countries from intervening her sovereignty issues, while the U.S. crafts “Air-Sea Battle”, in which the U.S. applies her devastating military and technology power, and combines the force of each ally to rein China’s military operation. All in all, with the China-U.S. competition as the backdrop, and by referring to John Mearsheimer’s offensive realism, this study examines the future Sino-American relations in the South China Sea. China, as a potential hegemon, possesses a large population and a fast-growing economy; the state also conducts military operations in the South China Sea, with a view to consolidating the mutual economic and trade dependence of China and the ASEAN, even countries in East Asia. Moreover, China excludes the U.S. from dealing with tasks in Asia for the purpose of replacing the U.S. as the Asia’s key player. China’s intransigency in the South China Sea particularly reveals her dominance in the region. Besides, in facing China’s rise in all aspects, the U.S., as the current hegemon, plays the role of “The Off-shore Balancer”. By mixing "Buck-Passing" with "Balancing", the U.S. brings together countries involved in the issue such as the members of ASEAN, Japan, and India to collectively rein the power imbalance in the South China Sea, so as to consolidate her dominance. Both China and the U.S. have raised the level of the South China Sea issue, and have scrambled to gain the dominance in the South China Sea. Therefore, in the future, the two countries will become more of two competitors in this region.

無 / Discussions of the South China Sea maritime territorial disputes are rife with assertions that certain state actors escalate regional tensions and that it is only a matter of time before provocations trigger armed conflict. However, these claims are based primarily on incomplete evidence, inaccurate comparisons with historical conflicts, and country or individual biases. This dissertation questions these common assertions and uses empirical evidence to assess their validity. Using time-series event data from the Global Database of Events, Language, and Tone (GDELT), it analyzes (1) the relationship between state involvement and South China Sea tensions and (2) which forecast models can most accurately predict South China Sea tensions based on data from earlier time periods. For RQ1, the analyses reveal that the involvement of certain countries corresponds with significantly higher tensions in the South China Sea, that state involvement and tensions are correlated at various positive and negative lags of interest, and that these correlations go in both directions. These findings have important implications for policymakers and researchers in that they offer empirical evidence that confirms or refutes assertions suggesting that certain countries’ actions lead to escalation or deescalation. They also provide a solid foundation for future research, which could take specific countries as individual case studies to further investigate the relationships between state involvement and South China Sea tensions. Moreover, the results indicate that there may be even more interesting phenomena at play that merit attention in future research: evidence suggesting that certain countries may either contribute to lower tensions or avoid becoming involved when there are heightened tensions, and evidence that some countries may not be contributing to but instead reacting to tensions and volatility in the South China Sea. For RQ2, two of the four forecast models perform better than the four benchmark models using both datasets. These findings also have important implications for policy and research. As governments become increasingly interested in using continuously updated global databases to facilitate policy-making, the results suggest that empirical data can help to inform conclusions about trends of escalation and deescalation in the South China Sea and be used to make relevant predictions. As a first cut at the data and a pioneering approach to analyzing South China Sea tensions, the analyses and findings of this dissertation represent a significant contribution to knowledge and a foundation for future research using time-series event data to understand the relationship between state involvement and tensions and the extent to which tensions can be forecasted in the South China Sea and around the world.