Plastic debris in the Laurentian Great Lakes System, North America: Analysis of types, abundances, and sources
Abstract
Understanding plastic pollution in the Laurentian Great Lakes system requires investigation of all plastic debris sizes and categories. Visible polymeric debris (VPD) mainly characterize shorelines, and microplastics (MPs;mm) are found in benthic and beach sediment. Field sampling of VPD from all five Great Lakes, visual and chemical identification of VPD types, and implementation of a matrix scoring technique (MST) indicate that plastic industries, urban areas, and shoreline recreation are major sources of VPD. Sampling for MPs in the St. Clair system, followed by preliminary density separation, and microscopy, suggest that wastewater treatment plants are a major source. This work is the first freshwater study to use an MST and the largest published lacustrine VPD study. The results should encourage industry, policy makers, and the general public to work towards a circular economy.