BOSTON (CBS) — A group of enthusiastic volunteers tackled a big cleanup project in the heart of Boston on Sunday. They converged on the Muddy River, which winds through the city’s Emerald Necklace area.

This is the second year for the Muddy Water Initiative, a grassroots environmental effort that pulls trash out of the waterway with a boom and net system known as the “water goat.”

“Today we’re cleaning up the water’s surface. It’s visible and it makes a difference because that trash sinks down and it turns into microplastics in the water,” explained Caroline Reeves.

Next year, with some funding help from the city of Boston, the group plans to filter some of the Muddy River water, with the goal of reducing the level of harmful chemicals that can trigger toxic algae blooms.