Fox News host Tucker Carlson ripped into immigrants in the nation’s capital, accusing them without evidence of contaminating the Potomac River.

In an interview with the Atlantic, Carlson said he’s been fishing in the river, which stretches from West Virginia into the Chesapeake Bay, for almost 35 years.

"It has gotten dirtier and dirtier and dirtier and dirtier," he said. "I go down there, and that litter is left almost exclusively by immigrants."

Asked how he knew immigrants were to blame, Carlson added: "Because I’m there. I watch it."

We found that Carlson’s claim is at odds with data collected by activists devoted to keeping the Potomac clean, who told us that the river has actually gotten cleaner over time.

Plus, there’s no evidence that immigrants are especially to blame for any trash floating around the river’s waters. (Fox News did not respond to requests for comment.)

Cleaner and cleaner, not dirtier and dirtier

The Potomac River has long been considered too polluted for swimming, particularly in and around Washington, D.C., where Carlson lives. Its waters were so bad that in 1965, former President Lyndon Johnson declared the river a "national disgrace."

But a 2018 report from the Potomac Conservancy, a nonprofit clean-water advocate in the region, found that the Potomac’s overall health has improved dramatically in the last 10 years.

Hedrick Belin, president of the group, blasted Carlson for his "groundless accusation" in a statement to PolitiFact, calling the Fox News host’s comments "factually incorrect" and "racist."

"For the first time in generations, we are within reach of fully enjoying a healthy, thriving Potomac River," Belin said, noting that river pollutants are in decline as fish are returning.

Other experts agreed. "This is a river that's getting cleaner and cleaner, not 'dirtier and dirtier,'" said Philip Musegaas, vice president of programs and litigation for the Potomac Riverkeeper Network. The nonprofit called Carlson’s claim "dead wrong" in a Facebook post.

Musegaas said plans to upgrade the sewer systems in Washington and Alexandria, Va., should eliminate the "last sources of untreated sewage pollution" in the nearby metropolitan area.

Curtis Dalpra, communications manager for the Interstate Commission on the Potomac River Basin, said different environmental issues affect different parts of the river, which is more than 380 miles long. But generally speaking, the river is cleaner than it was 30 years ago.

Still, Carlson was talking specifically about litter, so we also reached out to the Alice Ferguson Foundation, which organizes annual trash cleanups along the riverside and keeps tabs on the total amount of trash and recyclables its volunteers haul out of the Potomac’s shores each year.

According to the foundation’s data, less litter was collected in 2019 than in 2007, even as the number of volunteers increased. Specifically, the number of trash-and-recyclable-filled bags per volunteer dropped from an average of 2.14 bags in 2007 to 1.20 in 2019.

At Fletchers’ Cove — a spot that, according to the Washington Post, is roughly a 10-minute drive from Carlson’s house — the average number of bags-per-volunteer went from roughly 2.11 in 2007 to about 1.32 in 2019.

Litter isn’t the main problem

Local experts also cast doubt on Carlson’s claim that immigrant litter was at fault.

For starters, litter is not the top pollutant soiling the Potomac River’s waters. Belin said nutrients and sediment that flow off the land are the main causes for concern. When they hit the water, they harm wildlife, degrade habitats and taint the water, making it less clean and safe.

Litter is still an issue. But foreign-born people — who make up roughly 14% of the population in Washington, D.C., according to the Census Bureau — are not uniquely prone to littering.

"Littering is definitely a problem, but it is a problem that knows no color or ethnicity," Musegaas said. "Tourists litter, residents litter, and people fishing and boating on the river litter."

Not only that, but most of the trash that ends up in the Potomac River is not deposited directly, experts said. Often, trash left in the street or outside in barrels gets swept by rain into the sewer or the river.

Of course, that trash has to come from someone, Dalpra noted. At some point, it was thrown on the ground or stuffed in the trash. And in a dense city like Washington, there’s likely more litter to go around than elsewhere. But that litter "is really a problem that spans society," Dalpra said.

While we won’t discount the possibility that Carlson has spotted immigrants tossing trash in the Potomac, there’s no evidence that the litter "is left almost exclusively by immigrants."

Our ruling

Carlson said the Potomac River "has gotten dirtier and dirtier and dirtier and dirtier. I go down there and that litter is left almost exclusively by immigrants."

The available data shows the opposite; the Potomac has actually gotten cleaner. And there’s no evidence to suggest that immigrants are most responsible for the remaining litter in the river.

We rate this statement Pants on Fire!