6 | WINTER 2018 | GBF.ORG IMPORTANT INFO WHY WE NEED TO CARE ABOUT MICROPLASTICS IN THE GREAT LAKES HOW MUCH PLASTIC IS OUT THERE? The influx of plastic into the Great Lakes likely began over half a century ago, when industrial plastic production took off. Now, showing no signs of slowing down, annual plastic produc- tion has reached around 300 million metric tons after having doubled in the last 15 years. It is estimated that 60% of all plastics ever produced have either been diverted to land- fills or accumulated in the environment. Many of these are microplastics, derived from plastic debris breaking down into small fragments or entering the environment as microscopic particles. Measuring how many pieces of plastic are in the environment is not an easy task. To quanti- fy floating plastic, I have towed fine-mesh nets aboard research vessels and boats conducting citizen science, such as the youth training tall ships of Toronto Brigantine. Quantifying the number of microplastics can be time consum- ing – particles are individually separated, sorted and counted. While information on microplastics in the Great Lakes is limited compared to marine environments like the ocean gyres, a study on three of the Great Lakes (Lake Superior, Lake Huron and Lake Erie) showed the average abundance in surface water was approximate- ly 43,000 microplastic particles per square kilometer. In 2014, surface water was sampled in Lake Erie, Lake Ontario and the rivers that feed into them. Recorded abundances of microplastics were between 90,000 and 6.7 million particles per square kilometer. These levels of microplastics are similar to and even exceed concentrations found in ocean gyres like the “Great Pacific Garbage Patch.” The kinds of microplastics found in these stud- ies — largely fibers, fragments and spheres With my nitrile gloves and fish dissection kit, I am a cog in the machine investigating the impacts of plastic on the Great Lakes. Working with a team of researchers, we are helping to bring new understanding to a lake scattered with tiny pieces of plastic. By Lisa Erdle, PhD Student University of Toronto Microfibers <5mm from a Lake Ontario water sample collected in 2015.