CHICAGO (WLS) -- It's the 27th year for Chicago River Day where thousands of volunteers get together to clean up trash from the river.On Saturday, volunteers cleaned up and beautified 156 miles of shoreline. It's not just for aesthetics, but for the environmental impact to us and wildlife living here. This year they're starting something new to prevent trash from building up."We'll see birds, like seagulls or ducks with fishing line on them, or trapped in various types of garbage. But some of the litter we see interacting with the wildlife is really small. We've been collecting fish from the Chicago River, and from rivers in the area, and looking inside their digestive system to see exactly what kinds of litter are in their stomachs," said Tim Hoellein, an aquatic biologist at Loyola University.It's not just the trash in the water, but the litter around it, too. New this year, the trash that's collected will be analyzed."The next step we can take is to use the information in the trash, which means the types of trash that are out there, the numbers that we find. We can take all those value and try to analyze them from a scientific prospective to answer a few questions about the nature of the material," Hoellein said.Volunteers cleaned up 65 locations in the city and suburbs and there was a lot to tackle."We're happy to help out, it definitely needs it," said volunteer Katie Tobolik.Nonprofit organization "Friends of the Chicago River" makes this event their mission, rain or shine, to protect not just our waterways but people, plants and animals."We're working on not only on days like today, we're working to actually clean up the river physically, but we're also working on public policy to help improve it over time," said Margaret Frisbie with Friends of the Chicago River.Since its start, tens of thousands of volunteers have come together to remove 600 tons of trash from the river.