The Government of Indonesia has made ambitious commitments to improve waste management and tackle marine litter. In recent years, some global studies that estimated inputs of plastic waste into the oceans ranked Indonesia as one of the largest contributors to plastic marine pollution. The challenge of plastic waste and marine litter requires a robust national response to curb the significant impacts on Indonesian marine biodiversity, its communities and its economy. However, there is still lack of detailed understanding on the current state and origin of plastic pollution that is meaningful to design appropriate measures.
Mismanaged municipal solid waste transported via rivers
Our assessment indicated that mismanaged municipal solid waste in Indonesia results in plastic waste inputs into the sea between 201.1 and 552.3 kton/year, most of it transported via rivers. Huge amounts of plastic waste generated remain uncollected, in particular in rural areas. As such, communities lack sustainable alternatives to deal with their waste, relying on improper waste handling practices, such as burning and disposal of waste in waterways.
Transport and fate from source to sea
In the assignment, we constructed a spatially and temporally variable representation of the generation, transport and fate of plastic waste from source to sea, as a reflection of certain performances of waste generation and management from the communities that live within a catchment area.
Using Deltares suite of models, we simulated the mobilisation and transport of plastic in all major catchments in the country, considering the topography, elevation, soil-type, land-use and spatially and variable weather data, such as rainfall. These results were then aggregated to determine the contribution of each river to marine plastic pollution, the regencies/cities that are most problematic, as well as the total national estimate of plastic discharges from Indonesia into the marine environment.
Pinpointing where and which interventions are most needed
Such a detailed type of information can help the Indonesian government to tackle plastic pollution by pinpointing where and which interventions are most needed, as well as providing a realistic baseline against which progress in preventing plastic inputs into the sea can be tracked.
The study was welcomed by the Indonesian Coordinating Ministry for Maritime Affairs and Investment, who oversees marine litter policies in Indonesia.