He swam the polluted Gowanus Canal in Brooklyn and called it "pretty disgusting."
But after swimming the entire length of the 3.5-mile Newtown Creek on Wednesday, Christopher Swain says the canal experience doesn't compare.
"It was probably the worst, most disgusting swim I've ever done," he said of his Newtown Creek paddle. He said he saw "floating turds," used condoms and was enveloped in smells that couldn't be identified.
"There's all kinds of industrial chemical smells and tastes you don't get on the Gowanus," he said. "We smelled chemical smells similar to cinnamon toast, but we known it's not cinnamon toast."
Newtown Creek forms part of the border between Brooklyn and Queens.
Swain, a clean water advocate, has been calling attention to the city's polluted waterways by suiting up in protective gear and swimming through water that the federal government warns could be hazardous to human health. He swam the entire 1.8-mile Gowanus Canal in October.
Newtown Creek is a Superfund site that is home to one of the largest oil spills in the United States and is one of the most industrialized waterways in the city.
He said after his swim, clad in yellow gear, that he wants to see more than "some" cleanup done in the creek. "I want the finish line for Newtown Creek to be a creek that's safe for swimming every day."