To be successful, solutions to marine plastic pollution must be predicated upon a clear understanding of the issues based on sound science. This session discussed a review of scientific research on marine plastic pollution in South-East Asia and considered how critical research gaps can be filled. This work is a result of a team effort from several researcher centres of the National University of Singapore (NUS): the Centre for International Law (CIL), the Tropical Marine Science Institute (TMSI) and St John Marine Laboratory (SJML).

Publishing on marine litter in the region has boomed in recent years, but scientific literature research is not enough to identify the full breadth of what is being done. It is necessary to further build on our understanding of marine litter and plastic pollution status and ecosystems impacts, as well as human health impacts. Developing a more complete understanding of societal and economic aspects requires a long term commitment to developing the science.

The international trade in plastic waste for disposal and recycling has boomed. Social, economic, and environmental impacts arise as a result of mismanagement and weak accountability, prompting several countries in South-East Asia to impose restrictions on scrap plastic imports. This has led to spill over to other countries, and illegal trade persists. Governments in the region have started to adopt much stricter regulations and legal frameworks, changing the dynamics and movements of transboundary plastic waste.

Solutions to this intractable challenge involve understanding better the responsibilities of exporting and importing countries, increasing investment in plastic waste traceability, and developing recycling mechanisms, through creating demand in the manufacturing market for second-life plastics. This will contribute to closing the loop and minimising leakages from the system. Increasing legal instruments in the ASEAN region are important next steps in targeting legal and illegal imports of plastic scraps in the region. Solutions can be achieved by monitoring transboundary movement of plastics, enhancing sorting in exporting countries, building end-markets for secondary materials, designing products for recyclability and recycling, and investment in developing functional circular economies. Recipient countries were encouraged to better communicate globally the measures and guidelines they are putting in place to regulate trade. There is a demand for legally traded plastic waste for businesses, and this will also support environmental protection.

Scientific data is crucial in understanding the sources and drivers, dynamics and distribution of marine litter and the impacts on the environment. Data is also vital to formulate adequate management responses. The possibilities of new technologies, such as drones and remote sensing have improved data collection. Approaches from the global regional and national-level are needed. Better coordination is needed to avoid duplication of effort and filing of some key gaps. This will help us get “the bigger picture” and support better action planning. It is also important to involve the public whenever possible, and generate data products comprehensible to local populations through improved science communication.

The CSIRO Marine Debris Research Program is analysing data from beach clean ups to understand the effects of plastic bans. The Global Plastics leakage project validates estimates of pollution from land to identify hotspots and understand drivers of plastic pollution. UNEP is working to better understand the key hotspots, impactful polymers, products, life cycle stages and pathways in order to identify holistic solutions and key areas of interventions - and to support government converging towards instruments to implement the interventions. UNEP is also providing guidance for reports on the national level, and developing an online platform for user-friendly data on plastics which will be launched in 2020.

The UNEP CounterMEASURE Project utilizes multi-source satellite imagery to analyse the Mekong River and the project shares all their analysis and codes openly (CounterMEASURE website will be launched in 2020). The data includes statistics on seasonal plastic flooding patterns to identify peak discharge patterns and field data collections gathered with drones, to initiate beach clean-ups

In Indonesia, a National Plan put the focus on plastic pollution as priority. Joint efforts are underway between Indonesia and international partners to understand the hotspots through beach plastic debris monitoring. In the Citarum River, scientific outcomes were translated into action. In 22 sectors at the river delta, new technologies were used to empirically verify the modelling. The results showed that with 60% single use plastic, this is the highest contributor to plastic litter in the river delta. The majority of the items are plastic bags. The outcome of this research encouraged the local government of the 22 districts to take local regulations in action banning the use of single plastic goods. This example showcases the importance of linking data to target interventions.

Access to data on plastic flows and leakage points will allow for better understanding of how to keep plastics at the highest possible value chain - how we avoid polluting oceans and rivers. Standardized data collection and new technologies, such as drones and remote sensing, can be employed to better conduct and disseminate research. Citizen Science can be very useful to get the bigger picture of plastic debris pathways. Social Media can also prove useful in creating new citizen science platforms. Solutions could also be reached through a global data base, or project repository, incorporating information on production and consumption into analysis of plastic leakage and wastage, to better assess to address the extent of plastic debris.

Toxic, or potentially toxic properties of plastics were discussed - including chemical additives in plastics, and chemicals adsorbed to plastics in the marine environment. Discussants reviewed the implications and existent/proposed solutions from different perspectives of the plastic lifecycle, including design, recycling, waste-water treatment and policies interventions.

Research was shared on the hydrophobic additives which are retained in marine plastics and microplastics, and the accumulation of additives. Research on landfill leachate shows that they are a major contributor to high BPA levels in rivers in Tokyo. High levels of BPA are also found in sewage near landfill sites. Wastewater is not treated adequately to address BPA levels and impacts are longer lasting. Studies show that chemical can be bioaccumulated and affect humans. More research is needed on chemical contents in plastic products.

Hazardous flame-retardant additives are contained in many consumer products. Recommendations to limit POP levels in plastic products call for better lifecycle management. Full-scale plants to separate PBDE/bromine-containing polymers exist, but may be inadequate to process plastics if stronger limits are legislated in future. Solvent-based solutions can also separate polymers, are however costly. A full-scale plant for packaging material recycling is in operation in Indonesia. Hence, there is a need for non-toxic alternatives to substitute hazardous materials that are currently difficult/costly to separate and manage appropriately. A substitution approach can achieve a successful phase out and replacement of hazardous chemical additives. The tools exist, but capacity building is required across the board for alternatives assessments. The Stockholm Convention includes provisions for the phase-out and substitution of hazardous chemicals such as POPs. However, the challenge remains that there are many different types of plastics and a huge range of chemical additives. Therefore, there is a need for a comprehensive list of chemical additives and their positive/negative impacts.

Consensus was shared that a reduction, restriction and phase out of selected plastic products is required. In order to reduce landfill leachate, it is necessary to separate organic and non-organic waste. Segregation of plastic waste from organic waste at the individual level would prevent conversion of plastic into more toxic byproducts. Chemicals and additives should be prioritised in the design and production stages since it is too late and too costly to mitigate their effects in later stages. Priority actions to address chemicals in plastics include: regulation and enforcement, research, transparency, awareness and education, phase-out and reduction