The sources, pathways, quantities, and fate of plastic pollution are still uncertain. Despite Switzerland having a more efficient waste management system compared to other countries, recent studies have revealed significant plastic pollution in Swiss waters, including Lake Geneva.

The objective of this research is to determine the contribution of different sources to the plastic pollution in Lake Geneva and to compare the findings from two different approaches: a top-down approach using modeling to analyze socio-economic activities, plastic losses, and releases into the lake, and a bottom-up approach extrapolating plastic flows based on field measurements from six different pathways. This research provides new insights and understanding of the fate and pathways of plastic pollution while identifying methodological gaps.

The two methods produced results of comparable magnitudes and gave an initial estimate of the plastic flow from the land to Lake Geneva, which is approximately 55 tons per year.