Microplastic Pollution in Waters and its Impact on Health and Environment in Indonesia: A Review

Introduction: Microplastics have become a pollution problem that has received worldwide attention. Microplastics in the water impact the environment and health, especially in Indonesia, which is the second largest plastic waste contributor in the world. This literature study aims to determine the distribution of microplastics pollution in waters and its impact on health and the environment in Indonesia. Methods : The literature search on papers from 2010-2021 through Google Scholar, Pubmed, ScienceDirect, and ProQuest, with the keywords of ‘Microplastics’, ‘Indonesia’, ‘aquatic’, ‘environment’ found 477 articles. Then, after exclusion of duplicate articles, and other inclusion criteria, the final review was done on 42 articles. PRISMA guidelines was used for reviewing procedure. Results: Most microplastic research was conducted in Java Island, which is dominated by rivers and beaches. Based on the source, microplastics came from domestic waste, tourism and fishing activities. The most common forms found were black and blue fibers from fishing lines, nets and clothing fibers of various sizes. The type of polymer identified is polyethylene plastic. Microplastics impacted the tourist destinations, marine ecosystems through the food chain and also humans who consume seafood. Conclusion: Microplastics are found in the Indonesian marine environment. Humans can consume seafood contaminated with microplastics, which will have an impact on health. Therefore, health risk assessment should be done to provide information for taking environmental management efforts.


Introduction
Microplastics (MPs) are a growing pollution problem which recently expressed as a tremendous contaminant of all environmental components. 1,2 Then, microplastics received the attention of scientists, politics, media, the general public and various circles. [3][4][5][6][7][8][9][10][11][12][13][14][15] Asia is the region with the fastest growing waste production in the world. Five countries are responsible for more than 50% of all plastic waste in the oceans, all of

JOURNAL OF PUBLIC HEALTH FOR TROPICAL AND COASTAL REGION
(JPHTCR) Journal homepage: http:/ejournal2.undip.ac.id/index.php/jphtr/index ISSN : 2597-438 which are in the Asian region which is China, Vietnam, the Philippines, Thailand, and Indonesia. 16 Currently, plastic waste in Indonesia can be called an emergency because Indonesia is the second contributor to plastic waste in the world. 17 In 2019, Indonesia produced around 67.8 million tonnes and this will continue to grow as the population grows. 18 The source of plastic waste comes from residential areas and various industries which use plastic to package their products. 19 Apart from its very large source, plastic waste is dumped into the oceans, thus posing a serious threat to marine life. 20 Microplastics can pose a risk to marine organisms and ecological processes. This is also presumed to pose a risk to seafood security. 21 From various studies, more than 690 marine species have been affected by plastic waste with tiny plastic particles observed in the digestive tracts of organisms of various trophic levels. 22 Of the 192 countries in the world, only 22.9% (44) countries that have researched microplastics and their impact on organisms mostly target fish (38%). 23 Microplastics are often detected in the digestive tract of aquatic organisms. 24 In an African study, it was found that 35% of fish samples ingested plastic particles analyzed in the digestive tract. 5 Microplastics can also physically stick to the gills and skin of fish. 25 Other studies have revealed that excreted fish (whole fish excluding offal and gills) contained higher levels of microplastics than cut organs (offal and gills), highlighting that evisceration did not necessarily eliminate the risk of consuming microplastics by consumers. 26 Seafood is consumed by human worldwide, so the presence of microplastics has the potential to pose a food safety risk. 27 However, knowledge about the adverse effects on human health due to the consumption of marine organisms containing microplastics is still very limited. 28 But based on the literature, the potential toxicity of particle on human health can be focused on gastrointestinal toxicity, liver toxicity, neurotoxicity, and reproductive toxicity, which involves oxidation stress mechanisms, inflammatory reactions, and metabolic disorders. 29 Other toxicity produced is inflammation due to persistent microplastic properties, as well as its unique nature such as hydrophobicity and chemical composition, and it is suspected to have an accumulative effect depending on dosage. Microplastic has shown that cytotoxic effects induced in T98G and Hela cells (human brains and epithelial cells). 30 Polystyrene microplastic with a diameter of 460 nm and 1 μm can affect erythrocytes. 31 This literature study aimed to determine the distribution of microplastics pollution in waters and its impact on health and the environment in Indonesia.

Study Selection
The article search included Indonesian and English language articles with open access. This search was conducted through Google Scholar, Pubmed, ScienceDirect, and ProQuest.

Inclusion/Exclusion Criteria
The database search criteria utilized the keywords of 'microplastics', 'Indonesian', 'aquatic' and 'environment'. The articles accessed were articles from 2010 to 2021. The search found 477 articles. Data were extracted manually by research title, year of publication and research method.
The inclusion criteria for article searches were: 1) full text availability; 2) targeting microplastics in the aquatic environment. The exclusion criteria were: 1) theses, books, review articles, final assignments, papers, outline, and baseline; 2) double publication. Criteria for data storage in publications were: 1) location; 2) specific location; 3) source and type of plastic; 4) method; 5) shape; 6) polymer type, and 7) environmental and human impacts.

Data Extraction
This literature review referred to the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines. It can be seen in Figure 1.

Study Location
Forty-two articles were included in this review. The location of this study is presen -ted in Figure 2.
The locations of microplastics studies were mostly on Java Island. As can be seen in Figure  2, the least number of studies were Articles are included after reading references from articles taken (n = 6) done in Papua and Ambon. The high level of population concentration in Java compared to other islands motivates the researcher to relate the microplastics in the environment with anthropogenic factors. 32 The microplastic studies were mostly done in Java Island. A study showed that wastes were accumulated through Bengawan Solo River, which in turn due to the currents were carried into Java Sea. The microplastic in the currents then accumulates on the water of Banyuurip Village, East Java. The river estuary and sea is affected by the currents with a speed between 0,1-0,2 m/s. 33 In Surabaya, the majority of waste were came from domestic and industrial sources. 34 People living in the area of 500m radius from Surabaya River, dumps their domestic waste to the river body 35 and about 10 industrial waste outlets, dump their waste water to the river 34 . Other studies in East Java, one on Pantai Utara, East Java, founded that the high level of human activity is the catalyst of a high amount of plastic waste disposed into the sea. 36 The beach along Tuban Regency also has a high potential for microplastic contamination, with the higher concentration on the river estuary. Lack of proper microplastic management (incomplete burning, unplanned burning and dumping) can be the possible cause of microplastic transportation and their relative abundance around the beaches and river estuary area. Myriads of human activity directly affects areas as a waste disposal areas. 37 Plastic waste accumulation, indirectly, affects fishing capabilities, sea ecosystem, tourism sectors and the health of people around the coastline of Pasuruan Regency. 38 People's activity directly and indirectly causes an impact to the water environment around the coast of Mangunharjo Village, Tugu District, Central Java. 39 Kendal River in Central Java flows from the land to the sea with a length of 9.5 km, with 40.56 km 2 size of River Flow Area (DAS) and 216 m 3 /sec river water debit, has a potential to carry microplastic. 40 Human activity can contribute to microplastic contamination, such as on Ayah Beach Kebumen which is also a tourist destination and closed to a fishmonger. Daily plastic waste in Kebumen on 2018 was 9.09 tonnes or approximately 24% of the total managed waster. 41 Still on Central Java, there are 5 main rivers in Yogyakarta which ferries plastic waste from densely populated area to the sea in southern Yogyakarta, for example, is on Baron Beach, Gunungkidul Regency. 42 On the western area of Java, which is the Banten Gulf, plastic waste are spread through water flow and food chain and then reaching the island chain of Seribu. 43 The beach and rivers were the most specific places of studies.
Specific locations which highlights Beach and Rivers such as: Surabaya River 34 50 The source of microplastic waste as shown on Table 1 is dominated by domestic waste or from household activities. Indonesia is known as a dense populated country which certainly affects the abundance of microplastics. 42,65 The total plastic waste generation in Indonesia reaches 5.4 tons per year, which is 14% of the total amount of household waste. 66

Domestic wastes
Disposable plastic bags (45) Apart from household activities, the presence of microplastics is also influenced by tourism and fishing activities. Tourism activities conducted between tourists and tourism actors, directly and indirectly, can cause waste generation every day. A study from the United Nations Environment Program (UNEP) stated that tourists on average produce six times more waste when they were on vacation. 67 Fishing activities also affect the amount of plastic in the waters and on the other hand, fishermen will also be affected. The presence of plastic can hinder boat travel (waste of fuel), disturb aesthetics in tourist areas (loss to tourism), and interfere with health. 68

Shape, Size, and Colours of Microplastics
Shows the existence of 8 forms of microplastic (Fiber, Fragment, Film, Foam, Filament, Pellet, Granule, and Microbead) and each article did not only discuss and find one form of microplastic. The most microplastics form found was fibers of different sizes, which has been mentioned in 34 articles.
Fibre form of microplastic commonly comes from river or estuary areas due to the anthropogenic influences. 57 Fibre were found to be of the highest concentration in comparison with the three other type of plastic waste in Lekok Beach and Panjang Beach. The high level of fishing activity in both of these beaches is the reason for the fibres' abundance. 38 The microplastic comes from the usage of fish catching apparatus such as fishing rods and degraded fishing nets. 49 The most dominant type of microplastic that were identified inside the Lemuru Protolan fish were fibre. 51 In the other study, fibres were found on the digestive tract of Swanggi fish. It was assumed that it originates from the fishing catching apparatus and nets that were used. 36 On sea urchins, the average weight on fibre microplastic were found to be 0.0058g per individual, which is assumed due to fisherman activities using fishing nets. 69 Other than on biotas, fibres are also a type of microplastic which were most commonly found on sediments. 55 Fibre also comes from boat ropes that are no longer used by fishermen or ones that experience friction and then break down into very small plastic particles which are then carried away by inflows into the waters. 39 High amount of fibre type can also be suspected from the rest of the cloth of seat cover of bean bag which are directly placed on the beach 49 or from the clothing fibre of domestic waste. 44 Microplastics come in various forms, sizes and colors. Microplastics are usually defined as plastic waste which degrades and breaks down into small plastic particles ≤ 5 mm. 36 The size of microplastics can be divided into two which is large (1 -≤ 5 mm) and small (1 μm -≤ 1000 μm). 70 In all of the studies, the found smallest microplastic size was 28 μm and the largest size was 5 mm.
Various colors of plastic material are made with the addition of dyes. 34 The discovery of microplastics with various colors can be seen in Figure 3. The dominant colors are black (17%), blue (17%) and red (15%). The microplastics found during high and low tides are dominated by black, white, red, blue and green colored fibers. 57 Fiber is shaped like a thread with various colors such as blue, red and black. 39 Another study stated that the fibers found had a morphology similar to fishing nets or fibers with dark blue, light blue and red colors. 55 The color of microplastics on the surface of the river water, the middle depth and the bottom of the Surabaya river was found to be blue and black and red. 34 The color of microplastics at all stations, namely the river estuary were also found to be black, red, blue, pink. 47 The dominant colors of microplastics found in fish samples were black (38 particles), red (11 particles), blue (6 particles). 50 Black microplastic has a high ability to absorb pollutants. 71 In all microplastic studies the highest amount found was black. Black color can indicate the amount of contaminants absorbed in microplastics and other organic particles. Black microplastics also have a high ability to absorb pollutants, which also affects the texture of microplastics. 58 The black color indicates the types of polystyrene and polypropylene and is thought to also contain pollutants such as PAHs and adsorbed PCBs. 41 Staining in plastics can pose a potential eco-toxicological risk to aquatic biota due to the release of chemical compounds. 34 The color of the microplastic

Types of Microplastic Polymers
To identify the type of polymer, all of the studies used Fourier transform infrared spectrophotometry (FT-IR) test. FT-IR is the most popular technique and is often used to identify polymer types from microplastics. 49 The test results with FT-IR are in the form of graphs with specific wavelength values. This wavelength value shows the functional group of a compound. 39 Based on the results, the type of polymer found was dominated by polyethylene and polypropylene. The estimation of the types of polyethylene and polypropylene polymers in the sample was indicated by the presence of a wavelength peak was in the range of 2,935-2,915 cm -1 which was interpreted the presence of CH stretch bonds. 40 The peak results from the FTIR test of Sei Sikambing River water samples from the three locations contained bonds with the following wavelengths: 2913.47 cm -1 , 2846.07 cm -1 , 1463.13 cm -1 , 1371.86 cm -1 , 1028.23 cm -1 . These wavelengths are close to the standard wavelengths for polyethylene and polypropylene. 45 The low density polymers (low density polyethylene, polyethylene and polypropylene) of microplastic in the study were not only found on the surface, but also in the depths of other rivers. This condition can be affected by biofouling. Biofouling gradually forms a biofilm on the surface area of the microplastic. 34 Polypropylene can come from broken polypropylene-based chairs due to the abundance of such chairs along the coast. 49 Most of the microplastics are found with a dark color that can be used as an initial identification of polyethylene polymers which have low density which are abundant in surface waters. Polyethylene is the main ingredient in plastic waste bags and containers. 58

Impact of Microplastics for the Environment and Food Chain
Microplastic research in Indonesia focuses more on water and sediment. Studies globally state that microplastics have also been detected in water bodies and sediments on seven continents and four oceans. 73 Microplastics have the potential to disrupt the food chain if they accumulate in water areas. 52 Microplastics are present in all aquatic ecosystems and can be digested by a wide variety of organisms through consumption. [74][75] Sea fish are widely used as food for human consumption. 76 Therefore, many researchers have focused their studies on microplastics in fish, as can be seen in Table 2. Microbead 2

Discussion
The large amount of plastic waste that is disposed of has an impact on the development of tourism which is currently being intensively carried out by the government. Several tourist destinations have been affected. 77 Microplastics are more dangerous because they contain chemical compounds. For example, research on the coast of Cilacap, Indonesia, stated that the presence of highly toxic hydrophobic compounds had been confirmed in marine plastic waste. Thus, plastic waste can pose a threat to marine ecosystems, with the potential to release these POPs (persistent organic pollutants) into distant seawater or aquatic animal organisms, after ingestion. 78 Microplastics can harm marine organisms and even reach humans through the food chain/web. 79 The consumption of microphractic-containing fish may cause carcinogenic and non carcinogenic risk in humans, based on the intake rate. Both non-carcinogenic or carcinogenic risks indicate the strong relation with the concentration (C) of microplastic in fish, intake rate (R), shelf frequency (FE), exposure duration, and weight (WE) of the respondents. 80 Based on the results of the study, microplastics were found in all feces of samples of pregnant women in the working area of Puskesmas Pattingalloang and Jumpandang Baru, Makassar. Microplastics were found from thirty stool samples ranging from 5-21 microplastics with the types of fibers, fragments, and films due to fish consumption. 81 In the human body, after swallowing foods containing microplastic, it interact with the mucus layer of the digestive tract. Then, microplastic particles combine and cross the mucosal layer and in contact with epithelial cells. Microplastic is then transferred to lymphatic and circulatory systems, and through this system, microplastic reaches and builds up in organs such as the liver, the kidneys, the spleen, the heart and the brain which in turn have an effect on human health. 25 Alternative consumption of microparticles can cause changes of chromosomes which causes infertility, obesity, and cancer. 82 Ingestion of microplastics can cause local inflammation and cancer due to immune cell response, especially in individuals with metabolic disorders and poor cleansing mechanisms. 83 Polyvinyl chloride microplastics that enters into the digestive organs and human blood circulation systems can absorb and bind serum albumin, destroy the molecular structure and function of proteins, transfer to each organ through the blood, and further cause more serious in vivo damage. 84 Research on the adverse effects of microplastics on the environment and health in Indonesia is still limited. Therefore, it is necessary to conduct more in-depth research as well as efforts to reduce its impact. Research conducted in Tempode, Salama Village, Manggarai Regency, East Nusa Tenggara, to reduce the dangers and impacts of microplastics showed that it is necessary to introduce the management of coastal areas as part of the ecosystem through outreach activities to coastal communities. With the socialization, the public's understanding on the concept of marine waste, microplastics, and ecosystems has increased by 76%. 79 Apart from the efforts to manage the aquatic environment, it is important to estimate the intake of microplastics in humans. Estimates on the global average, humans can ingest 0.1-5 g of microplastic each week via various exposure routes. 85 Considering the potential risk of contamination, the edible parts of fish and food sizes that are safe for adults is 300g/ week and for children is 50g/ week. 86

Conclusion
Microplastics are very dangerous for the environment and humans. Humans are exposed to microplastics through food chain contamination. Therefore, analysis and assessment of the potential health risks has to be done to provide information and make the right decision. Efforts to overcome these problems must be carried out, especially in reducing the accumulation of plastic waste in the ocean environment and strict regulation for the use of plastic products.

Author Contribution
SBK contributes to conceptualization, writing the sections of "the presence of microplastic in Indonesia by general and specific locations," "the source and type of plastic" and "the microplastic forms." SH and EMS contribute to the sections of "the microplastic identification methods" and "the environmental and health impacts on humans due to microplastic" BK contributes to the sections of "data analysis method", prepared the tables and figures, editing the language. All authors read the manuscript and approve the final manuscript.