As a significant contributor of plastic waste to the marine environment, Indonesia is striving to construct a national strategy for reducing plastic debris. Hence, the primary aim of this study is to create a model for plastic waste quantity originating from the mainland, accumulated in estuaries. This was achieved by compiling baseline data of marine plastic disposal from the mainland via comprehensive contextualisation of data generated by remote sensing technology and spatial analysis. The parameters used in this study cover plastic waste generation, land cover, population distribution, and human activity identification. These parameters were then used to generate the plastic waste disposal index; that is, the distribution of waste from the mainland, flowing through the river, and ultimately accumulating in the estuary. The plastic waste distribution is calculated based on the weighting method and overlap analysis between land and coastal areas. The results indicate that 0.6% of Indonesia, including metropolitan cities, account for the highest generation of plastic waste. Indicating of plastic releases to the ocean applied by of developing three different scenarios with the highest estimation 11.94 tonnes on a daily basis in an urban area, intended as the baseline study for setting priority zone for plastic waste management.

Low priority on waste management has impacted the complex environmental issue of plastic waste pollution, as evident by results of this study where it was found that 24.3% of waste generation in Jakarta and Bandung is emitted into the waterway due to the high intensity of human activity in the urban area. In this study, we investigated the viable integration between material flow analysis and leakage hotspot modeling to improve management strategies for plastic pollution in water systems and open environments. Using a multi-criteria assessment of plastic leakage from current waste management, a material flow analysis was developed on a city-wide scale defining the fate of plastic waste. Geospatial analysis was assigned to develop a calculation for identification and hydrological analysis while identifying the potential amount of plastic leakage to the river system. The results show that 2603 tons of plastic accumulated along the mainstream of the Ciliwung River on an annual basis, and a high-density population like that in Bandung discarded 1547 tons in a one-year period to the Cikapundung River. The methods and results of this study are applicable towards improving the control mechanisms of river rejuvenation from plastic leakage by addressing proper management in concentrated locations.

Determination of plastic leakage sources and pathways is essential in plastic pollution mitigation. Finding ways to stem land-sourced plastic waste leakage requires understanding its sources. Spatial analysis conducted in a geographic information system (GIS) environment and remote sensing investigation uncovered insights into the distribution of plastic leakage in the lower Mekong River basin (LMRB). The main objectives of this approach were: (i) to map plastic leakage density using multi-source geospatial data; and (ii) to identify plastic leakage source hotspots and their accumulation pathways by incorporating hydrological information. Mapping results have shown that plastic leakage density was highly concentrated in urban areas with a high intensity of human activities. In contrast, the major pathways for plastic leakage source hotspots were the high morphometric areas directly influenced by facilities, infrastructure, and population. The overall efforts in this study demonstrate the effectiveness of the proposed novel method used for predicting plastic leakage density and its sources from land-based activities. It is also accomplished using multi-geospatial data with GIS-based analysis to produce a graphical model for plastic leakage waste density in each region that non-technical personnel can easily visualize. The proposed method can be applied to other areas beyond the LMRB to improve the baseline information on plastic waste leakage into the river.

Today the world faces the fact that 10 million tonnes of waste, primarily plastic waste, pas through the river. This global issue has become a serious problem that can be resolved with location-based that utilizes remote sensing technology, following recent developments of technology. This study aims to estimate the weight of potential plastic waste at the estuary before it enters the ocean and becomes marine debris. Several parameters are developed based on three main aspects, which are environment as graded by LULC, social aspect as provided by population density using building data, and economic aspect as provided by nightlight from NOAA’s VIIRS. The estimation used raster-based digital numbers processing, by using estimated data and providing weight. As a result, it shows that most of the metropolitan cities such as Jakarta contribute almost 507 tonne of plastic waste per day. For other cities, its generation is directly proportional to the increase in population. This study could become a consideration to synthesize policies, with the fact that massive population density impacts the increasing of the plastic waste generation.

Low priority on waste management has impacted the complex environmental issue, where this study found out up to 24.3% of waste generation in Jakarta and Bandung is emitted to the waterway due to the high intensity of human activity in the urban area. In this study, we investigated the viable integration between material flow analysis and leakage hotspot modelling to improve the management strategy of the plastic pollution in the water system and open environment. Using the multi-criteria assessment through the plastic leakage from its management, a material flow analysis has developed on the city scale. Comprehensively identifying using potent identification and hydrological characterization, plastic waste from Jakarta city has occasionally estimated 2603 ton discarded to Ciliwung River while the plastics from Bandung Area has contributed to 1547 ton, addressing Cikapundung River as the main tributary of Citarum mainstream in annual basis.