Estimation of the leakage amount of Plastic Litter into the Environment

It is important to estimate the total amount of plastic litter discharged into the environment, including the oceans and develop an inventory of its source and amount as basic information to steadily promote measures against plastic pollution and to monitor progress in this area. In addition, a globally applicable harmonized methodology of estimating the amount of plastic litter discharged into the environment, including the oceans, is necessary to promote international efforts to deal with plastic pollution.

1. Estimation of the amount of Marine Plastic Litter Discharged in Japan

This work involves the study of methods for estimating amount, and efforts to develop an inventory for evaluating the amount of plastic litter discharged into the ocean in Japan.

However, these results are not definitive values, and all estimation formulas and data used are provisional based on information
available as of FY2024.
We will continue to refine and update the estimation based on the latest results of related surveys and research.

Results of the study as of the FY2024

Results as of the FY2024 Estimated Amount of Marine Plastic Litter Discharged in Japan

Results of the study as of the FY2025

Results as of the FY2025 Estimated Amount of Marine Plastic Litter Discharged in Japan

2. Toward estimation of the of Global Plastic Leakage into the environment, including the Marine Environment

This work involves the study of methodologies for estimating and developing an inventory for evaluating the amount of global plastic leakage into the environment, including the marine environment.

Publication of ‘Guidance on Estimation Methods for Inventory Development of Plastic Leakage into the Environment, Including the Marine Environment’

MOEJ published the ‘Guidance on Estimation Methods for Inventory Development of Plastic Leakage into the Environment, Including the Marine Environment’ in May 2026. This guidance systematizes the existing international and Japanese estimation methodologies in a catalogue style for evaluating the amount of global plastic leakage into the environment, including the marine environment. It is a method-selection and implementation guide and provides a stepwise workflow so that users can select the most appropriate methodology for their purpose and for each dataset categorized by statistical data (production, consumption and waste management) and field survey data. These estimation methodologies include not only those for the total leakage amount, but also those for developing an inventory estimated by sources and items.
Please refer to the “References” for the list of sources cited in the guidance.

【Guidance】
Guidance on Estimation Methods for Inventory Development of Plastic Leakage into the Environment, Including the Marine Environment

【Project Materials】
Project on Inventory Development Methodology for a Plastic Leakage into the Environment, Including the Marine Environment (FY 2025)

【Project Material from Previous year】
Project on Inventory Development Methodology for a Plastic Leakage into the Environment, Including the Marine Environment (FY 2024)