Microplastic Pollution in High Population Density Zones of Selected Rivers from Southeast Asia.

Southeast Asia (SEA) faces significant environmental challenges due to rapid population growth and economic activity. Rivers in the region are major sources of plastic waste in oceans. Concerns about their contribution have grown, but knowledge of microplastics in the area is still limited. This article compares microplastic levels in sediment and water from urban zones of three major rivers in SEA: Chao Phraya River (Thailand), Saigon River (Vietnam), and Citarum River (Indonesia). The study reveals that in all three rivers, microplastics were found, with the highest concentrations in Chao Phraya's water (80 ± 60 items/m3) and Saigon's sediment (9167 ± 4559 items/kg). The variations in microplastic sizes and concentrations among these rivers may be attributed to environmental factors and the exposure duration of plastic to the environment. Since these rivers are important water supply sources, rigorous land-use regulations and raising public awareness are crucial to mitigate plastic and microplastic pollution.

Identification of illegally dumped plastic waste in a highly polluted river in Indonesia using Sentinel-2 satellite imagery.

Plastic waste monitoring technology based on Earth observation satellites is one approach that is currently under development in various studies. The complexity of land cover and the high human activity around rivers necessitate the development of studies that can improve the accuracy of monitoring plastic waste in river areas. This study aims to identify illegal dumping in a river area using the adjusted plastic index (API) and Sentinel-2 satellite imagery data. Rancamanyar River has been selected as the research area; it is one of the tributaries of Citarum Indonesia and is an open lotic-simple form, oxbow lake type river. Our study is the first attempt to construct an API and random forest machine learning using Sentinel-2 to identify the illegal dumping of plastic waste. The algorithm development integrated the plastic index algorithm with the normalized difference vegetation index (NDVI) and normalized buildup indices. For the validation process, the results of plastic waste image classification based on Pleiades satellite imagery and Unmanned Aerial Vehicle (UAV) photogrammetry was used. The validation results show that the API succeeded in improving the accuracy of identifying plastic waste, which gave a better correlation in the r-value and p-value by + 0.287014 and + 3.76 × 10-26 with Pleiades, and + 0.143131 and + 3.17 × 10-10 with UAV.

Identification of fibrous suspended atmospheric microplastics in Bandung Metropolitan Area, Indonesia.

Most research mainly focused on microplastics in the aquatics and terrestrial environment, whereas studies related to microplastics in the atmospheric environment are still limited. This study aims to identify microplastics in Total Suspended Particulates (TSP) in two different spatial areas. The measurement and study was to represent the commercial area (urban area) and residential area (sub-urban) in Greater Bandung City, Indonesia. Suspected microplastics were identified by visual observation using a digital microscope, then were confirmed by the hot needle test method. Microplastics fibres were found in all samples with a concentration range of 0.3-0.6 particles/m3 in the commercial area and 0.1-0.3 particles/m3 in the residential area. Black is the dominant colour of microplastics both in the commercial and residential areas, which counted up to 77.2% and 81.8% respectively. Microplastics fibres have various sizes, with the dominant size ranging from 1000 to 1400 µm in the commercial area and 600-1000 µm in the residential area. The proven occurrence of microplastics in Greater Bandung Region and in other parts of the world can be used to attract attention on further study on source, fate, impact, and possibility of a new air quality monitoring parameter.

Microplastic distribution in surface water and sediment river around slum and industrial area (case study: Ciwalengke River, Majalaya district, Indonesia).

Microplastic research in urban and industrial areas, including remote areas, have been conducted recently. However, there is still a lack of research about microplastic abundances in slum area. Ciwalengke River is located in Majalaya, Indonesia, which is dominated by slum and industrial areas that probably generate microplastics. This research was conducted to investigate the distribution of microplastic around the slum area for the first time. Surface water and sediment samples of the river were obtained at ten locations and grouped into six segments location based on different land use at the riverbank. Microplastic particles were identified using binocular microscope and categorized by shape and size. The average microplastic concentration were 5.85 ±â€¯3.28 particles per liter of surface water and 3.03 ±â€¯1.59 microplastic particles per 100 g of dry sediments. Microplastic concentration in the sediment samples were found to have significant differences in location segment (Kruskal Wallis test, p-value = 0.01165 < 0.05), but no significant differences were found in the water samples (Kruskal Wallis test; p-value = 0.654 > 0.05). In addition, microplastic distribution was dominated by fiber particle. More fiber shape might be derived from the direct clothing of residents in the river and fabric washing process in the textile industries. This was also revealed by Raman spectroscopy test of several microplastic particles indicating that the type of microplastic were polyester and nylon.