GREENPOINT — The man who's paddled through the most polluted channels in the city to advocate for cleaner waters, emerged from the toxic soup of Newtown Creek Wednesday cold and shivering, his left eye red and swollen from water that had seeped through his mask.

He declared the waterway the "worst, dirtiest water," he'd ever been in, after his 3.5 mile swim.

"This is just from a guy who swims in poop as a vocation," said Christopher Swain, 47, shivering on the banks of the slimy creek after the swim. "Newtown is the worst...This is much worse than Gowanus."

While Swain said that his was not a scientific assessment of the water quality, the creek was viscerally the most repulsive body of water he'd ever paddled through.

"We saw floating turds, we saw used condoms," he said. "A lot of nasty things you'd see on the street."

Beyond the debris the canal was ripe with "industrial smells and tastes," like oil fumes and the mysterious smell of cinnamon toast at one point along the way, he said.

Newtown Creek, which was designated as a Superfund site in 2010 by the federal government, is one of the country's most polluted waterways with an extensive history of oil refineries, glue factories, sawmills, chemical and metal plants and a sewage treatment facility along its shores that dumped and leeched pollutants into the water.

Many factories still operate along the shores and the Newtown Creek Wastewater Treatment Plant is the city's biggest sewage treatment plant. Storm runoff from the streets and sewage overflow from the overburdened treatment plant continue to muck up the waters.

Before embarking on his swim the Environmental Protection Agency had warned Swain against the endeavor, advice that he'd shrugged off with the hastags "#idontcare" and "#cantgetenough."

Dear Sweet #NewtownCreek, even the #epa says you are bad for me #idontcare #youdoitforme #cantgetenough #sueme #swimwithswain A photo posted by Christopher Swain, Swimmer (@swimwithswain) on Dec 22, 2015 at 11:36am PST

Garbed in a puncture-resistant search and rescue suit, earplugs, goggles, swimming cap, and with his face coated in a water-wicking gel, Swain dipped his booties into the water at 8:20 a.m. on Wednesday morning at the East Branch tip of the canal near the Grand Street Bridge on the border of East Williamsburg and Maspeth and headed west from there.

He finished up just before noon and paddled out into the East River to let the salt water begin to clean off some of the toxins, though he planned on bathing in a water and bleach mixture later in the day, he said.

Twice during the swim, creek water got into his mouth and he had to rinse with hydrogen peroxide, he said.

"I see why people think I need counseling," the swimmer admitted.

Over the course of his nearly two-decade career of swimming in toxic waters, Swain has suffered skin rashes, ear infections, sore throats and swollen lymph nodes the size of ping pong balls, he said.

"I'm willing to freeze, I'm willing to swim in poop, I'm willing to put myself on the line. I'm willing to risk my health," he said. "You gotta be willing to have some skin in the game..if you really want to make change in the world."

Swain hopes that his paddling down the Newtown Creek and extensively documenting the journey with water samples and thousands of pictures, will encourage a cleanup of the creek.

"All these urban waterways they were stolen from us," he said. "They've been taken away and I'd like to steal them back."

Swain plans on swimming the creek's four other tributaries — Whale Creek, Maspeth Creek, Dutch Kills and English Kills — over the course of the next few months, he said.

"Unless someone puts themselves on the line, nothing changes," he said.