Annual Boston Harbor debris cleanup begins

They do the work by hand, using a humble net bag on a stick, as you would to clean a swimming pool. Valencik said she’s seen systems used in other harbors, such as Baltimore’s, that draw in water and strain the trash out, but Boston Harbor has so many jellyfish and so much seaweed that such a system would be quickly gummed up here.

Once pulled from the water, the debris is stored at the Black Falcon Cruise Ship Terminal in South Boston until enough has accumulated for a contractor to pick it up. Plastic bottles and metal containers are recycled by Save That Stuff Inc., and most of the rest goes into landfills.

Valencik agreed with Li that environmental factors are a major cause of trash making its way into the water.

“A part of it is due to negligence, people not being careful about throwing things away or just throwing it in the street,” Valencik said. “But a large part of it actually comes from things like the wind. Some of the trash cans don’t have covers on it, or they’re overfull and they just get blown into the water. ... Another thing is also storm drains. Like whenever it rains, things just get washed into the water.”

Winds, rains, and tides also cause the trash to pool in certain areas around the harbor, Valencik said, including between the wharves of the North End, downtown, and South Boston; near the new Spaulding Rehabilitation Hospital in Charlestown Navy Yard; and in the inlet between Jeffries Point and Logan International Airport in East Boston.

Though some trash is unavoidable, Valencik said she’s seen great improvement from the days when “you could barely drive out of the channel, you would just be coming across so much trash.”

Efforts to make people more aware of where their trash goes have paid off, Valencik said, and it helps that many people who work along the waterfront or have boats there see the cleanup crews and find out about their work.

“People will see us out here, ask what we’re doing,” she said, “and they see what we collect and they are usually pretty outraged at the fact that there is this much stuff in the water.”

Li said there’s still more we can do to prevent trash from entering the waters.

“Most of the items, aside from the pilings, are things that we really can prevent coming into the harbor,” she said. “So our message always is, we’d like you to put the program out of business by being sure there’s no more debris in Boston Harbor. And we can all do our part to clean up the harbor.”

Email Jeremy C. Fox at jeremycfox@gmail.com.

(Jeremy C. Fox for Boston.com)

Sarah Valencik fished trash out of Boston Harbor on Thursday.