Kyoto, 13-18 March 2023: The 3R International Scientific Conference on Material Cycles and Waste Management (3RINCs) opened this week, bringing together more than 400 researchers and students for a 6-day knowledge sharing occasion. The 9th annual conference, which was convened at Kyoto University after fully being held online for two years during the COVID-19 pandemic, aimed to enhance the practice of sustainable production and consumption through Reduce, Reuse, and Recycle (3R).

Academics and practitioners from 24 countries shared the latest development and discoveries within the field of waste management in different sessions.  

‘The Special Sessions initiated discussions within 8 important topics namely plastics, mercury waste management, open dumping and burning, Integrated Solid Waste Management (ISWM) and net zero, international cooperation, landfill management, and regional 3R and circular economy forum in Asia Pacific,’ said Dr Yasuhiko Hotta, Programme Director of Sustainable Consumption and Production Area at the Institute of Global Environmental Strategies (IGES), who oversaw the session.  

The General Sessions, meanwhile, have welcomed a total of 129 presentations with a wide range of disciplines including municipal solid waste, plastic pollution, e-waste, and disaster waste.  


Kyoto University, the venue of the 9th 3R International Scientific Conference on Material Cycles and Waste Management. (Photo courtesy: 3RINCs)


Protecting Mangrove Ecosystems from Plastic Pollution 

During the conference, the Regional Knowledge Centre for Marine Plastic Debris (RKC-MPD) had an opportunity to present our latest research on stocktaking good practices in protecting mangrove ecosystems from plastic pollution—with a case study in Indonesia.  

‘Home to the largest area of mangrove forest in Southeast Asia with a total area of 3.3 million hectares, Indonesia’s mangroves are under immense threat of surging amounts of plastic pollution,’ said Ms Ellen Putri Edita, a research associate from the RKC-MPD 

Mangrove forests in different parts of Indonesia had seen plastic waste build-ups as a result of land-based plastic leakage that flowed through the river and became trapped within the complex mangrove roots, based on an information from the Ministry of Marine Affairs and Fisheries Indonesia in 2023. This impacted on several growth problems, especially to mangrove seedlings.   

She then emphasized, ‘With mangroves being one of the largest blue carbon sinks, safeguarding it is therefore of high importance. 

The key point in protecting mangroves from plastic pollution lied on minimizing plastic flow in the river, which would eventually end up in mangrove forests that sat at the mouth of the river. This could be done both through direct and indirect measures.  


The RKC-MPD team member presents about plastic pollution prevention in mangrove ecosystems.


From Indonesia, we gathered direct good practices including The Ocean Clean Up’s Interceptor 001 in Cengkareng Drain, trash racks, and bamboo fence in Mangrove Forest Protection Area. 

‘In principle, these direct measures worked by filtering plastic and preventing it from flowing further downstream. The indirect good practices, on the other hand, worked by preventing the leakage of plastic waste in the first place through measures such as reducing plastic consumption and improving waste management,’ Ms Ellen said. 

The act of preventing plastic pollution in mangroves did not come without its own set of challenges. In terms of prevention, there is no specific regulation in place about plastic pollution in mangroves in Indonesia. With mangrove forest sitting in between land and sea, there would be a possible conflict of interest in its governance. Furthermore, in terms of handling the cumulated plastic waste in mangrove, mangrove clean-up and restoration are still difficult to be executed.  

Plastic debris monitoring method in Mekong River Basin 

Reliable data is essential in making policies and initiatives that are necessary in addressing plastic waste issues. For this reason, the Mekong River Commission, in collaboration with IDEA Consultants, developed a long-term and cost-effective monitoring method for riverine plastic debris particularly in the Lower Mekong River Basin. 

The protocol covered monitoring methods for riverine macroplastic, microplastic, and microplastic content in fish. Ms Kotone Iwamoto, a Junior Researcher at IDEA Consultants, explained that for monitoring microplastic ingested by fish, they chose 12 types of fish commonly caught in the four countries of the Lower Mekong River Basin as the suggested protocol.  

‘This monitoring protocol is now on progress to be released, which we hope will enable the collection of standardized monitoring data of riverine plastic debris in the region,’ added Ms Iwamoto. 

A presentation on Kyoto SDGs by the Mayor of Kyoto. (Photo courtesy: 3RINCs)

Also read: Plastic Pollution in Mekong River Basin: The Importance of Multi-Stakeholder Collaboration

The necessity of plastic products: Japanese consumers’ perception 

Consumers are one of the main stakeholders in achieving plastic circularity. Intervention to consumers’ behaviour, notably on the consumption and utilization of plastic products, hence needed to be addressed.  

Dr Yuta Ando, a researcher from Kyoto University, presented the results of a survey that collected Japanese consumers’ view on the necessity and substitutability of selected 50 plastic products that are frequently used and disposed daily.  

Based on 10,000 respondents, more than 44 percent of the plastic products were considered unnecessary and that there were more sustainable substitutes available on the market. The evaluation on demographic factors showed that gender and age were correlated with consumers’ views.  

‘The accumulated data can be further used to inform the development of a roadmap of future measures that are needed to address issues related to plastic products at the individual-product level,’ concluded Dr Ando. 

The opening of the 3RINCs reception dinner.

Also read: India-Japan Environment Week Shares Innovative Waste Management Technologies to Reduce Plastic Waste