Several article have appeared recently about plastics in the oceans and Great Lakes including this one by Maryse Jobin for Radio-Canada:
Des chercheurs alarmés par la quantité de plastique dans les Grands Lacs [Scientists alarmed by quantity of plastics in the Great Lakes]
The article highlighted the alarming quantity of "micro-plastics", small filaments and beads invisible to the naked eye, which have been found accumulating in major water bodies and oceans.
Dr. Kristen Mitchell was quoted about the Ecohydrology group's research into remote sensing techniques to track the location and magnitude of these particles in the Great Lakes.
More information about this research can be found at the University of Waterloo's Marine Debris Research page.