Step 4: Mismanaged Waste and Leakage

Overview of the process to determine the share domestic waste that is mismanaged and the fraction of the latter that is leaked to oceans and waterways.

Plasteax scheme highlighting the step that determines the share of plastic waste that is mismanaged and, eventually, gets leaked into water.

A key output of the model is the estimation of how much waste from the different categories is mismanaged, meaning it ultimately ends up in the environment at the end of its life cycle. This mismanagement can occur due to littering, lack of waste collection, or improper disposal (e.g., disposal in unsanitary landfills).

To estimate the proportion of waste that is littered, littering rates (percentages of waste littered) are applied to various categories and polymers, based on data from a Eunomia report that observed littering behaviour in Europe.

For waste that is uncollected or improperly disposed, external data sources such as Eurostat, Census reports, national statistics, and scientific publications are used. The model for these disposal fates mirrors the approach used for landfilling and incineration, but in this case, the remaining waste quantities are adjusted by subtracting the amounts allocated to landfilling and incineration too (in addition to those of recycling, export, and littering).

Once the quantities of mismanaged waste (littered, uncollected, and improperly disposed) are calculated, the final step of the model estimates how much of this waste reaches oceans and freshwater bodies. Release rates specific to different waste categories are applied, without distinguishing by polymer. These rates depend on factors such as the size of the category and its value in the informal waste sector. Categories with higher value are more likely to be recovered from dumpsites by the informal sector, reducing the likelihood of waste entering waterways.