Tài liệu đánh giá sự ô nhiễm vi hạt nhựa trong bụi không khí khô và ướt ở thành phố hồ chí minh, việt nam

VIETNAM NATIONAL UNIVERSITY – HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY FACULTY OF ENVIRONMENT AND NATURAL RESOURCES DEPARTMENT OF ENVIRONMENTAL MANAGEMENT ------------------- TRUONG TRAN NGUYEN SANG ĐÁNH GIÁ SỰ Ô NHIỄM VI HẠT NHỰA TRONG BỤI KHÔNG KHÍ KHÔ VÀ ƯỚT Ở THÀNH PHỐ HỒ CHÍ MINH, VIỆT NAM ASSESSMENT OF MICROPLASTIC POLLUTION IN DRY AND WET ATMOSPHERIC FALLOUTS IN HO CHI MINH CITY, VIETNAM Major: Environmental and Natural Resources Management Course’s ID: 8850101 MASTER THESIS Ho Chi Minh City, February, 2020 CÔNG TRÌNH ĐƯỢC HOÀN THÀNH TẠI TRƯỜNG ĐẠI HỌC BÁCH KHOA –ĐHQG –HCM Cán bộ hướng dẫn khoa học : TS. Kiều Lê Thủy Chung…………………… TS. Emilie Strady…………………………… Cán bộ chấm nhận xét 1 : PGS.TS. Lê Trình Cán bộ chấm nhận xét 2 : PGS.TS. Đặng Vũ Bích Hạnh.…………………. Luận văn thạc sĩ được bảo vệ tại Trường Đại học Bách Khoa, ĐHQG Tp. HCM ngày 06 tháng 01 năm 2020. Thành phần Hội đồng đánh giá luận văn thạc sĩ gồm: (Ghi rõ họ, tên, học hàm, học vị của Hội đồng chấm bảo vệ luận văn thạc sĩ) 1. PGS.TS. Phùng Chí Sỹ (Chủ tịch Hội đồng) 2. PGS.TS. Lê Trình (Cán bộ phản biện 1) 3. PGS.TS. Đặng Vũ Bích Hạnh (Cán bộ phản biện 2) 4. TS. Trần Bích Châu (Uỷ viên) 5. TS. Lâm Văn Giang (Thư ký hội đồng) Xác nhận của Chủ tịch Hội đồng đánh giá LV và Trưởng Khoa quản lý chuyên ngành sau khi luận văn đã được sửa chữa (nếu có). CHỦ TỊCH HỘI ĐỒNG TRƯỞNG KHOA MÔI TRƯỜNG VÀ TÀI NGUYÊN PGS.TS. PHÙNG CHÍ SỸ ĐẠI HỌC QUỐC GIA TP.HCM TRƯỜNG ĐẠI HỌC BÁCH KHOA CỘNG HÒA XÃ HỘI CHỦ NGHĨA VIỆT NAM Độc lập - Tự do - Hạnh phúc NHIỆM VỤ LUẬN VĂN THẠC SĨ Họ tên học viên: Trương Trần Nguyễn Sang MSHV: 1870490 Ngày, tháng, năm sinh: 13/02/1995 Nơi sinh: Vĩnh Long Chuyên ngành: Quản lý Tài nguyên và Môi trường Mã số : 8850101 I. TÊN ĐỀ TÀI: Đánh giá sự ô nhiễm vi hạt nhựa trong bụi không khí khô và ướt ở Thành phố Hồ Chí Minh, Việt Nam (Assessment of microplastic pollution in dry and wet atmospheric fallouts in Ho Chi Minh city,Vietnam). II. NHIỆM VỤ VÀ NỘI DUNG: - Nhận diện (i) sự có mặt của vi nhựa (dạng sợi và mảnh) trong bụi không khí khô và ướt ở TP.HCM và (ii) đặc tính vật lý của vi nhựa: hình dạng, kích thước, màu sắc. - Khảo sát sự thay đổi của mật độ vi nhựa tích lũy trong không khí ở TPHCM theo thời gian (1 năm khảo sát) và tại các khu vực thu mẫu khác nhau (các yếu tố môi trường xung quanh). III. NGÀY GIAO NHIỆM VỤ : 19/08/2019 IV. NGÀY HOÀN THÀNH NHIỆM VỤ: 08/12/2019 V. CÁN BỘ HƯỚNG DẪN (Ghi rõ học hàm, học vị, họ, tên): TS. Kiều Lê Thủy Chung TS. Emilie Strady Tp. HCM, ngày CÁN BỘ HƯỚNG DẪN (Họ tên và chữ ký) TS. Kiều Lê Thủy Chung tháng năm 2019 CHỦ NHIỆM BỘ MÔN ĐÀO TẠO (Họ tên và chữ ký) TS. Emilie Strady TS. Lâm Văn Giang TRƯỞNG KHOA MÔI TRƯỜNG VÀ TÀI NGUYÊN (Họ tên và chữ ký) PGS.TS. Võ Lê Phú ACKNOWLEDGEMENT I would like to express my special appreciation and thanks to my principal supervisor Dr. KIEU LE THUY CHUNG and co-supervisor Dr. EMILIE STRADY. I would like to thank them for encouraging my research and for allowing me to grow as a research scientist. Their advices on both research as well as on my career have been priceless. Without their supervisions and constant help, this thesis would not have been possible. I would also like to thank all academic staffs of the ASIAN CENTER FOR WATER RESEARCH (CARE) for their valuable advice, comments, suggestions as well as encouragements during my study. My special thanks to Dr. LE THI MINH TAM, the CARE laboratory manager, for her useful help and advice for my research. Thanks to all my colleagues of CARE for their support and encouragement. Finally, yet importantly, I would like to send my special thanks to my family and all of my friends. They were always supporting and encouraging me with their best wishes. Master Thesis ABSTRACT Nowadays, the fate of plastic debris, especially microplastics (MiPs) (particles smaller than 5 mm) in marine aquatic systems has become a major worldwide environmental issue due to harmful effects on marine organisms and human health through seafood or salt ingestion. Last 2 decades, the land-based origin of MiPs and the role of rivers and estuaries on their emissions to the ocean was considered. Occurrence of MiPs in urban compartments, consisting of wastewater, surface water and atmospheric fallout was found in developed countries in recent studies. However, in low income countries, characterized by high waste mismanagement, relative studies are still limited. This study firstly addresses a preliminary assessment of microplastic (MiP) pollution in atmospheric fallout in Ho Chi Minh City. MiP particles (fibers or fragments) was found in all samples collected from three sampling sites: S1- urban area (District 10), S2 - sub-urban area (Cu Chi district) and S3 - Phuoc Hiep landfill. The analysis result showed that average concentrations of microplastics in the atmospheric fallout during 1 one-year monitoring were 402 ± 209, 142 ± 64, and 551 ± 139 items.m-2.d-1 from sites S1, S2 and S3, respectively. In terms of size range and color distribution, over 50 % of found fibers at all sampling sites was under 1,100µm in length, but difference on surface area of fragments was recorded. Items in blue, made up over 95% of total MiPs was the dominant in comparison with ones in pink, transparent, violet, white and green. Master Thesis TÓM TẮT LUẬN VĂN Thời gian gần đây, sự tích lũy một khối lượng lớn rác thải nhựa và đặc biệt là các vi nhựa (MiPs) (nhựa có kích thước nhỏ hơn 5 mm) trong môi trường nước đã trở thành một vấn đề môi trường lớn trên toàn Thế giới, gây ra nhiều tác động có hại đối với sinh vật biển và sức khỏe con người thông qua các chuỗi thức ăn và tận dụng độ mặn của nước biển trong làm muối ăn. Trong 2 thập kỷ qua, nguồn gốc của các MiPs trong các lục địa và vai trò của các con sông và cửa sông trong việc phát tán chúng ra các đại dương đã được xem xét và chứng minh trong các nghiên cứu. Sự xuất hiện của MiPs trong các thành phần đô thị, bao gồm nước thải, nước mặt và bụi khí quyển đã được tìm thấy ở các nước phát triển trong các nghiên cứu gần đây. Tuy nhiên, ở các nước kém phát triển, được xem là nguồn phát sinh khối lượng lớn rác thải nhựa trong môi trường, các nghiên cứu tương tự vẫn còn chưa được tiến hành sâu rộng. Nghiên cứu này lần đầu tiên tiến hành đánh giá sơ bộ sự ô nhiễm MiPs trong bụi không khí khô và ướt tại thành phố Hồ Chí Minh. Trong 72 mẫu được thu thập tại ba vị trí: S1- khu vực nội thành (quận 10), S2 - khu vực ngoại thành (huyện Củ Chi) và S3- bãi rác Phước Hiệp trong 1 năm nghiên cứu, các vi nhựa (dạng sợi và mảnh) đều được tìm thấy. Kết quả phân tích cho thấy mật độ trung bình của vi nhựa có trong bụi không khí lần lượt là 402 ± 209, 142 ± 64 và 551 ± 139 vi nhựa. m-2.ngay-1 tại các vị trí S1, S2 và S3. Về hình dạng và kích thước của vi nhựa, kết quả nghiên cứu ghi nhận được hơn 50% các vi nhựa được tìm thấy là dạng sợi và có chiều dài dưới 1.100 µm. Trong khi vi nhựa dạng sợi được tìm thấy trong tất cả 72 mẫu, vi nhựa dạng mảnh chỉ được tìm thấy trong một số mẫu và có diện tích bề mặt thay đổi khác nhau từ 10,000 µm2 đến hơn 80,000 µm2. Về mau sắc, các vi nhựa có màu xanh lam chiếm hơn 95%, các vi nhựa có màu hồng, trong suốt, tím, trắng và xanh lục cũng được tìm thấy nhưng với phần trăm không đáng kể và phân bố khác nhau trong các mẫu quan sát. Master Thesis CERTIFICATE OF ORIGINAL AUTHORSHIP I, Truong Tran Nguyen Sang, declare that this thesis is submitted in fulfillment of the requirements for the thesis evaluation, in the Faculty of Environment and Natural resources at the University of Technology, Vietnam National University Ho Chi Minh City. This thesis is wholly my own work unless otherwise references or acknowledged. In addition, I certify that all information sources and literature used are indicated in the thesis. This document has not been submitted for qualifications at any other academic institution. This research is supported and funded by Ho Chi Minh City University of Technology, VNU-HCM, under grant number To-MTTN-2018-11 Signature Date: February, 10th, 2020 Master Thesis 0 CATEGORY CATEGORY…………….. ......................................................................................... i LIST OF FIGURES ................................................................................................... iii LIST OF TABLES ..................................................................................................... v LIST OF ACRONYMS ............................................................................................. vi CHAPTER 1 INTRODUCTION ................................................................................ 1 1.1 Necessity of the research ........................................................................... 1 1.2 Research objective ..................................................................................... 3 1.3 Study area .................................................................................................. 3 1.4 Research content ........................................................................................ 3 1.5 Methodology and research Techniques ..................................................... 3 1.5.1 Methodology .................................................................................... 3 1.5.2 Research Techniques ........................................................................ 4 1.6 Scientific and practical value of the research ............................................ 4 CHAPTER 2 LITERATURE REVIEW ..................................................................... 6 2.1 Situation of plastic pollution in the world and Vietnam ........................... 6 2.2. Overview on microplastic pollution ........................................................ 10 2.2.1. Definition and properties of Microplastic ...................................... 10 2.2.2. Sources of microplastics generation into the environment ............ 11 2.2.3. MiPs Formation and factors affecting to the abundance of atmospheric 14 2.2.4. The harmful effects of MiPs pollution on the environment, organisms and humans ..................................................................................... 16 2.2.5. General research situation on Microplastic pollution in the world and Vietnam...................................................................................................... 19 2.3. Chapter Summary .................................................................................... 24 CHAPTER 3 MATERIALS AND METHODS ....................................................... 26 3.1. Study area ................................................................................................ 26 3.2. Sampling and pre-treatment .................................................................... 27 3.3. Visual observation and FTIR analysis ..................................................... 30 3.4. Data analysis ............................................................................................ 31 3.5. Chapter summary ..................................................................................... 32 CHAPTER 4 -THE OCCURANCE OF MICROPLASTIC IN DRY AND WET ATMOSPHERIC FALLOUTS OF HO CHI MINH CITY...................................... 33 4.1. The occurrence of microplastic in atmospheric fallout of Ho Chi Minh City…… ............................................................................................................... 33 Truong Tran Nguyen Sang Page i Master Thesis 4.1.1. Number of microplastics found in the sampling sites .................... 33 4.1.2. Shape of microplastics found at the three sampling sites .............. 34 4.2. Concentrations of MiPs at the three sampling sites ................................ 38 4.2.1. Site 1: urban area (District 10) ....................................................... 38 4.2.2. Site 2: sub-urban area (Cu Chi district) .......................................... 40 4.2.3. Site 3 – Phuoc Hiep landfill ........................................................... 41 4.3. Spatial variation of microplastic concentration in atmospheric fallout ... 43 4.4. Temporal variation of microplastic concentration .................................. 45 4.5. Chapter summary ..................................................................................... 48 CHAPTER 5 - PHYSICAL CHARACTERISTICS OF MICROPLASTIC IN ATMOSPHERIC FALLOUTS IN HO CHI MINH CITY ...................................... 50 5.1 Size of fibers and fragments measured at the sampling sites .................. 50 5.1.1. In District 10 ................................................................................... 50 5.1.2. In Cu Chi district ............................................................................ 51 5.1.3. In Phuoc Hiep landfill .................................................................... 52 5.2. Color distribution of fibers and fragments found at three sampling sites 54 CONCLUSIONS AND RECOMMENDATIONS ................................................... 64 REFERENCES… 67 APPENDIX…….. ................................................................................................... A1 Truong Tran Nguyen Sang Page ii Master Thesis LIST OF FIGURES Figure 2.1 The increase of global plastic production, measured in tones per year, from 1950 through to 2015 (Gayer et al., 2017)………………………………………….. 6 Figure 2.2 Estimated historic trends in global plastic disposal method (from 1980 to 2015) (Gayer et al., 2017)…………………………………………………………... 7 Figure 2.3 Route of plastic items enters the world’s oceans (Ritchie and Roser, 2018) ……………………………………………………………………………………….8 Figure 2.4 Global plastic input to the oceans by region, 2015 (Lebreton et al., 2017) ……………………………………………………………………………………….9 Figure 2.5 Size range of plastic debris in comparison with living materials (GESAMP, 2015)………………………………………………………………………………. 11 Figure 2.6 Formation and accumulation of microplastic particles …………………13 Figure 2.7 Potential MiPs sources and pathways (Liu et al., 2019).......................... 14 Figure 2.8 Studies were defined according the number of individuals per groups of organisms (De et al., 2018)………………………………………………………... 16 Figure 3.1 Sampling sites with geographic distances ………………………………26 Figure 3.2 Sampling device for dry and wet atmospheric fallouts………………… 28 Figure 3.3 Protocol for extraction of MiPs fibers from atmospheric fallout samples ……………………………………………………………………………………...30 Figure 3.4 Stereomicroscopic S6D integrated with a MC170 camera…………….. 30 Figure 4.1 Abundance of micropastic particle found per sample at three sampling sites (from 15th June, 2018 to 25th May, 2019)……………………………………. 34 Figure 4.2 Percentage of total microplastic fibers and fragments found in all samples at sampling sites………………………………………………………………….... 37 Figure 4.3. Percentage of total microplastic fibers and fragments found in all samples of each sampling site………………………………………………………………. 37 Figure 4.4. Concentration of microplastic fibers and fragments found in District 10 40 Figure 4.5 Concentration of microplastic fibers and fragments at Cu Chi district… 41 Figure 4.6. Concentration of microplastic fibers and fragments at Phuoc Hiep landfill ……………………………………………………………………………………...42 Truong Tran Nguyen Sang Page iii Master Thesis Figure 4.7 Concentration of atmospheric MiPs at each sampling site…………….. 43 Figure 4.8 Concentration of MiPs compared to volume of rain water (ml) at each sampling site a) site 1, b) site 2 and c) site 3………………………………………. 45 Figure 4.9. Monthly Concentration of microplastic (items m-2 d-1) at the three sampling sites……………………………………………………………………... 47 Figure 4.10 Concentration of atmospheric microplastics on site S1, S2, S3 in parallel with daily rainfall (volume of rainwater)………………………………………….. 47 Figure 5.1 Cumulative percentage of a) length of microplastic fibers (m); b) area of microplastic fragments (m2) in District 10………………………………………. 51 Figure 5.2 Cumulative percentage of a) length of microplastic fibers (m); b) area of microplastic fragments (m2) in Cu Chi District………………………………….. 51 Figure 5.3 Cumulative percentage of a) length of microplastic fibers (m); b) area of microplastic fragments (m2) in Phuoc Hiep landfill……………………………… 52 Figure 5.4 Cumulative percentage of a) length of microplastic fibers (m); b) area of microplastic fragments (m2) in three sampling sites……………………………… 53 Figure 5.5 Total microplastics with colors found in the atmospheric fallout collected in sampling sites a) S1, b) S2 and c) S3…………………………………………… 54 Figure 5.6 Percentage of fibers in colors found in the atmospheric fallout collected in sampling sites a) S1, b) S2, c) S3……………………………………………….. 56 Figure 5.7 Percentage of fibers in colors found in the atmospheric fallout collected in sampling sites a) S1, b) S2, c) S3…………………………………………………. 58 Figure 5.8 The example of microplastics (under stereomicroscope)……………… 63 Truong Tran Nguyen Sang Page iv Master Thesis 0 LIST OF TABLES Table 2.1 Overview of sources of two types of MiPs (Duis and Coors, 2016)…... 12 Table 4.1. Number of microplastic fibers and fragments found at three sampling sites………………………………………………………………………………... 33 Table 4.2. Concentration of microplastic fibers and fragments found at three sampling sites……………………………………………………………………................... 38 Table 4.3 Concentration of microplastics in different areas……………………… 49 Table 5.1 Characteristics of observed microplastics in the similar and different area studied…………………………………………………………………………….. 61 Truong Tran Nguyen Sang Page v Master Thesis 1 LIST OF ACRONYMS Microplastics MiPs Microplastic MiP Ho Chi Minh City HCMC Wastewater treatment plants WWTPs Truong Tran Nguyen Sang Page vi Master Thesis 1. CHAPTER 1 INTRODUCTION 1.1 Necessity of the research Nowadays, plastic pollution is an emerging concern worldwide. According to the statistic report, plastic production is continually increasing, with 299 million metric tons produced in 2013 and estimations of 33 billion tons for 2050 (Rochman et al., 2014). Number of plastic wastes (consisting of in-use plastics) entering the oceans was calculated for 2010 at 4 –12 million tons per year (Jamback et al., 2015). In 2015, there were more than 407 million tons of plastic was produced, followed by 302 million tons of plastic pieces (around three-quarters) were discharged into the ocean (Gayer et al., 2017). Recently, scientists from Netherland reported that about 1.15 to 2.41 million tones of plastic debris were released into the ocean daily. Besides, authors firstly pointed out the temporal change of marine plastic emission, with over 74 % of plastic items were distributed into ocean in rainy season (Lebreton et al., 2017). The presence of plastic wastes caused a dramatic change of the nature of solid wastes in human society, especially in developing countries where plastic products are often mismanaged or abandoned in illegal dumping sites (Stanton et al., 2019). As a result, these plastic particles are scattered throughout the oceans and are found along the coastal zones, in seabed sediments, beach sands, or floating on water surface and even in frozen ice in Arctic and Antarctic regions as well as accumulating in continental aquatic systems, consisting of lakes, canals and rivers. (Barnes et al., 2009). The existence of plastics in the aquatic system poses challenges on the world’s environment. The 2030 Agenda for Sustainable Development and its Sustainable Development Goals dedicated several necessary goals that are relevant to this issue (e.g. SDG 11, SDG 12, SDG 14), especially the Target 14.1 which states: “By 2025, prevent and significantly reduce marine pollution of all kinds, in particular from landbased activities, including marine debris and nutrient pollution”. Under the impacts from many factors such as mechanical processes, oxidation, and biodegradation, microplastics (MiPs), plastic particles that less than 5 mm in size (Arthur, 2009) are formed and can last thousands of years in the environment due to their chemical stability and durability. MiPs are considered as a new pollutant that is of great concern Truong Tran Nguyen Sang Page 1 Master Thesis by the world due to deleterious effects on the survival and reproduction of aquatic organisms through ingestion and accumulation (Ma et al., 2019) as well as affect human health through seafood or salt ingestion and inhalation of airborne MiPs (Prata et al., 2018). Recently, global studies have shown the distribution and harmful effects of MiPs on marine environments such as seas (Zhu et al., 2019; Zhao et al., 2018; Thompson et al., 2004), freshwater lakes (Rios mendoza & Balcer, 2019; EerkesMedrano et al., 2015), rivers (McCormick et al., 2014; Moore et al. 2008), and terrestrial environments (Jambeck et al., 2015). In Vietnam, Lahens et al (2018) also reported that the concentrations of MiPs in the water of HCMC’s canals and Saigon river varied from 270 to 518×103 fibers/m3 and from 7 to 223 fragments/m3 (Lahens et al., 2018). While the presence of plastic debris in the marine environment is widely documented, their sources, dynamic and fate in rivers and estuaries remain poorly understood and largely undocumented (Gasperi et al., 2018; Dris et al., 2015b). Among the sources of MiPs, urban inputs such as wastewater treatment plant effluents are increasingly studied while the atmospheric compartment is mostly neglected, though the fact that plastic debris can escape as wind-blown debris was previously reported, leading to human exposure and the potential for subsequent health risks (Gasperi et al., 2018). HCMC is the most dynamic area as a social, cultural and economic center of Vietnam, where services, exchange of goods and traffic in this area have been expanded for a long time which drives economic growth, followed by a dramatic increase of air pollution. In a recent study on the relationship between air pollution and human health in HCMC, over 90% of children less than 5 years old were infected by respiratory disease (Ho, 2017). The presence of MiPs in atmospheric fallout have become an environmental and social challenge due to their ability to spread (i) toxic additives added during plastics production or (ii) organic and inorganic contaminants adhering on MiP surface to the aquatic environment. More seriously, these small particles can accumulate in human’s body during the inhalation, then enter the nose and mouth and cause lung diseases (Gasperi et al., 2018). Truong Tran Nguyen Sang Page 2 Master Thesis Therefore, it is urgent to conduct a survey on MiPs contamination in atmosphere in terms of human health risk. The lack of data on sources and fate of plastic contamination in rivers and estuaries in developing countries makes HCMC, the economic capital of Vietnam and one of the most dynamic developing cities from South East Asia, an adapted pilot study site to study MiPs in the atmospheric fallout. 1.2 Research objective The objective of the study is to characterize MiPs pollution in the dry and wet atmospheric fallout in HCMC. 1.3 Study area Dry and wet atmospheric fallout samples were collected from three following sites: 1) Urban area (on the roof of CARE building, University of Technology, district 10); 2) Suburbs area (house of local people in Cu Chi district); 3) Phuoc Hiep Landfill. 1.4 Research content To obtain the research objective, a one year monitoring on the occurrence of MiPs in dry and wet atmospheric fallout was conducted in three different areas of HCMC (urban zone, countryside, landfill) in order to: - Determine the presence of MiPs (fragments and fibers) in the dry and wet atmospheric fallouts in HCMC, - Characterize (i) their physical characteristics such as type, size, shape and (ii) chemical composition, and - Investigate temporal variation of atmospheric MiPs concentration through the year, respectively related to the surrounding environment. 1.5 Methodology and research Techniques 1.5.1 Methodology Microplastic pollution has become one of global environmental issues in recent decades. At present, studies on MiPs mainly based on the investigation of concentration of these small particles in the environment. In this study, a long-term monitoring (in 12 months) was conducted at three sampling sites (urban, sub-urban area and a landfill) for preliminarily assessing the concentration of MiPs in the Truong Tran Nguyen Sang Page 3 Master Thesis atmosphere in HCMC. Experiments were set up in 4 main steps: (i) sampling, (ii) sample treatment, (iii) sample filtration and (iv) visual observation using the stereoscope. As a results, the presence of MiPs as well as their characteristics (shape, size, color) in HCMC was illustrated and in comparison with that of different areas in the world. 1.5.2 Research Techniques Methods used in implementing the research are as follow: - Theory analysis and synthesis: a literature review on definition, characteristics, sources and impacts of MiPs on the environment, organisms and human health was necessary for understanding the research field. The summary on situation of relative studies will clarify the research gaps at the present, as a result the research objective become more impressive. Besides, methods for collecting and treating samples used in previous studies can be applied with adaptation for the current study, allowing more objective comparisons. - Sampling and laboratory treatment: this technique is important in experimental researches. Results of these studies were mostly based on the data from collection and sample analysis at the laboratory. Practical monitoring data will provide the current sate of the area studied, describe more realistically environmental conditions affecting to the research subject. Therefore, discussions and comparisons become more objective and convincible. - Data analysis: results from sampling and laboratory analysis was firstly showed in raw data and difficult for describing research results. Data analysis methods, using analytical and statistical tools for arranging, re-formatting, performing data on tables and charts are necessary to clarify the results and key findings of the study. 1.6 Scientific and practical value of the research This study will thus i) be the first one in this scientific topic to be leaded in Vietnam, ii) will be the first one conducted in a developing country where the waste and plastic waste management differed strongly from developed country (so far no Truong Tran Nguyen Sang Page 4 Master Thesis papers dealing in developing country were published, and iii) will bring new knowledge on the MiPs in the atmospheric environment. Data on composition, nature, and distribution of MiPs in the atmosphere will raise awareness of residents on microplastic pollution and be helpful for the Department of Natural Resources and Environment, as well as the Ministry of Natural Resources and Environment in making plastic waste management solutions and propose measures to prevent, control and minimize plastic pollution on rivers and canals. Truong Tran Nguyen Sang Page 5 Master Thesis 2. CHAPTER 2 LITERATURE REVIEW 2.1 Situation of plastic pollution in the world and Vietnam In original, plastic was defined as "malleable" or "flexible" material used widely for manufacturing most of industrial products (Moore, 2008). Due to their numerous properties such as resistance, lightweight, durability and low cost, plastic items have been used worldwide in households, schools, hospitals and factories, leading to the global annual production of plastic polymers has grown tremendously from 1.7 in 1950 to 350 million tons in 2015 (Gayer et al., 2017) and are forecasted to double by 2025, and triple by 2050 (Plastic Europe, 2016) (Figure 2.1). Nowadays, plastic is a common material used in place of glass, metal, wood, leather, fabric, etc. to produce daily items, such as raincoats, water pipes, household items and industrial products owing to advantage characteristics as durable, light, cheap, hard to break and colorful. At present, the most widely used type of plastic are Polyethylene (PE), Polypropylene (PP), Polystyrene (PS) and Polyethylene terephthalate (PET), more than 90% of plastic products all over the world are made up these types (Andrady and Neal, 2009). Figure 2.1 The increase of global plastic production, measured in tones per year, from 1950 through to 2015 (Gayer et al., 2017) For decades, the production and consuming of plastic products produce a large number of plastic wastes, leading to a dramatic nature change of solid wastes in human society. More seriously, as a results of poor waste management and low Truong Tran Nguyen Sang Page 6 Master Thesis recycling rate (as can be seen in Figure 2.2, from 1980 to 2015, only 55 percent of global plastic waste was discarded, the remaining was incinerated and recycled, accounted for 25% and 20%, respectively) (Geyer et al., 2017; Ritchie & Roser, 2018), significant number of plastic wastes was found on worldwide centennial environment and finally entered and persisted in marine ecosystems through natural impacts as river runoff and atmospheric transport, beach littering and human activities as shipping and fishing. According to data on global estimates from Jamback et al. (2015) along with plastic waste generation rates, coastal population sizes and waste management practices by conutry, Ritchie and Roser. (2018) calculated and described pathway by which plastic enters the world’s oceans, as a result the amount of plastic in surface waters was estimated ranging from 10,000 to 100,000 tons per year (Figure 2.3). Figure 2.2 Estimated historic trends in global plastic disposal method (from 1980 to 2015) (Gayer et al., 2017) Truong Tran Nguyen Sang Page 7