Mapping Plastic and Plastic Additive Cycles in Coastal Countries: A Norwegian Case Study

The growing environmental
consequences caused by plastic
pollution
highlight the need for a better understanding of plastic polymer cycles
and their associated additives. We present a novel, comprehensive
top-down method using inflow-driven dynamic probabilistic material
flow analysis (DPMFA) to map the plastic cycle in coastal countries.
For the first time, we covered the progressive leaching of microplastics
to the environment during the use phase of products and modeled the
presence of 232 plastic additives. We applied this methodology to
Norway and proposed initial release pathways to different environmental
compartments. 758 kt of plastics distributed among 13 different polymers
was introduced to the Norwegian economy in 2020, 4.4 Mt was present
in in-use stocks, and 632 kt was wasted, of which 15.2 kt (2.4%) was
released to the environment with a similar share of macro- and microplastics
and 4.8 kt ended up in the ocean. Our study shows tire wear rubber
as a highly pollutive microplastic source, while most macroplastics
originated from consumer packaging with LDPE, PP, and PET as dominant
polymers. Additionally, 75 kt of plastic additives was potentially
released to the environment alongside these polymers. We emphasize
that upstream measures, such as consumption reduction and changes
in product design, would result in the most positive impact for limiting
plastic pollution.