Plastics in the Global Environment Assessed Through Material Flow Analysis, Degradation and Environmental Transportation

Abstract

Knowledge on plastic emissions to the environment and accumulation in time and space is vital for the development of successful mitigation strategies and risk assessments of plastics. In this study, plastic losses to the environment and human exposure are assessed on a global level through a yearly mass flow analysis. Countries, industrial sectors and environmental compartments are distinguished. Globally, 0.8 million metric tonnes (mmt) of microplastics and 9.5 mmt of macroplastics were emitted to the environment in 2017. Packaging contributed most for macroplastics, and tyre wear for microplastics. Both micro and macroplastics are mainly released to soils, including roadside, natural and residential soil. Additionally, accumulation, degradation and environmental transportation processes of plastics are considered for different environmental compartments until 2050. Macro- and microplastics will accumulate in the environment to 2.1 million metric kilotonnes (mmkt) and 4.1 mmkt in 2050 respectively (scenario: yearly consumption increase of 4%). This will be 30% less when a yearly production reduction of 1% until 2050 is modeled to 1.5 and 3.0 mmkt macro and microplastics respectively. Almost 2.5 mmkt of micro and macroplastics accumulate in the environment until 2050 with zero plastic production after 2022 due to leakage from landfills and degradation. Most micro and macroplastics will accumulate in natural soils, subsurface soils and the subsurface of aquatic environments. Results are compared to modeling studies that use both similar and alternative modeling methods. The current study distinguishes in aquatic compartment other than ocean, predicting lower emissions to ocean and higher emissions to surface waters including lakes and rivers. Terrestrial compartments are observed to accumulate most plastics emitted to the environment. The approach used in this study results in a flexible and adaptable model that addresses plastic losses to the environment over time and space, with detail on country level and environmental compartments.

Keywords: Mass flow analysis, plastic pollution, Microplastics, accumulation, Degradation, Environment