In the past few months, people who live along Duluth's Park Point have been picking up shredded aluminum cans — by the bagful — on the neighborhood's Lake Superior beach.
The metal fragments were inadvertently deposited there last fall, when the U.S. Army Corps of Engineers dredged sediment from the harbor to help build back the eroding shoreline.
Neighbors started noticing the metal-studded sand back in October, when a woman walking her dog on a part of the beach near Duluth’s Canal Park found a sharp shard of an aluminum can wedged the animal’s paw.
The dog was fine. But it wasn't long after, said Dawn Buck, president of the Park Point Community Club, that others began to notice more and more bits of metal on the beach, glinting in the sun.
"Sure enough, neighbors went down there and started collecting the shredded cans and pieces of metal shards on the beach — and also in the water,” she said.
Before winter set in, Buck said, people who live along the Point — a spit of sand and neighborhood that juts southeast into Lake Superior off downtown Duluth — had filled several trash bags with sharp metal debris from a stretch of beach just across the water from the city's Aerial Lift Bridge.
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"That's a huge, very active beach,” Buck said. “It's the closest beach to town, people just coming across from Canal Park. There's the hotels down on Park Point here. The beach is very busy. So yeah, it's worrisome."
The shredded metal had emerged from the sand along the same stretch of beach that the U.S. Army Corps of Engineers had rebuilt in the fall.
They sprayed about 50,000 cubic yards of sediment, sand and silt dredged from shipping channels in the Duluth harbor. The beach has been severely eroding, after years of rising water and monster storms, some of the many effects of climate change on Lake Superior.
U.S. Army Corps of Engineers spokesperson Bill Dowell says the agency was surprised to hear about the emerging metal. But now they think they know where it came from.
"We believe there was an area that that we dredged that hadn't been dredged in some time, that somebody had dumped these aluminum cans, probably around the 1970s just based on the vintage of the cans," he said.
The Army Corps of Engineers estimates that about 27,000 cubic yards of dredge material came from the area where they've since discovered the old cans. That's enough sand to cover a football field more than 10 feet deep.
The Corps did test the sediment before it was dredged, to make sure it would be safe to deposit on the beach. But that testing was for toxic materials, not for trash.
"This dredge equipment does have screens on it,” he said, “but the screens were about the size that an aluminum can would still fit through. And so that's what we think happened."
The Corps is now monitoring the beach, and have helped local volunteers with cleanup. The city of Duluth is urging caution to anyone walking there.
Plans call for the Park Point shoreline replenishment project to continue into the next section of beach this summer.
If it moves forward, the sediment would be sprayed right behind neighbor Jan Karon's house. She spent every day in the month before Thanksgiving picking up pieces of the old cans along the beach a few blocks before her yard.
"What I wanted was to … be able to trust that if they do it again next year, which will be literally in my backyard, that I can trust that it will be a safe process,” she said. “I have not seen or heard what they would do specifically to make sure that the same problem didn't occur."
Dowell said he's confident his agency can work out a solution to make sure cans and other trash aren't deposited along with the sand later this year.
In the meantime, he said, monitoring and cleanup of the beach will continue into the spring.
Buck said the Park Point Community Club, a neighborhood organization, is encouraged that the Army Corps is “owning the problem.” She also said residents will continue doing their part to keep the beach safe.
“We are committed to returning the beach to a safe condition,” she said, “by removing these hazardous artifacts.”