BROOKLYN, N.Y. -- With each steady stroke, John Lipscomb inched the canoe deeper into an infamous urban waterway. The water surrounding the boat grew increasingly murky; the sulphuric stench more offensive.
"Onward we go into the heart of darkness," said Lipscomb, boat captain for the clean water advocacy group Riverkeeper, as the tips of his oars again disappeared beneath the grey-brown surface of the Gowanus Canal.
Before long, the floating debris became too dense to outmaneuver. Tampons, condoms and human feces -- mixed with plastic lids, straws and wrappers -- bobbed around the boat, re-assorting with each stroke.
Lipscomb slowed, then filled the noticeable silence onboard: "It's too gross for words."
Although this Brooklyn waterway is an extreme example, its pollution illustrates the often "direct connection between our waterways and our toilets," explained Lipscomb. The common pathway: antiquated plumbing that carries sewage, industrial wastewater and rainwater together to treatment plants. A number of older U.S. communities sit atop these combined systems. Once considered state-of-the-art, today they pose serious problems that go well beyond a noisome nuisance.
A quarter-inch of rain can be enough to overburden the multi-use pipes that serve the majority of New York City neighborhoods. As a result, about 27 billion gallons of the mix spews into the city's surrounding waters annually via combined sewage outflows, so-called CSOs, according to Riverkeeper. Lipscomb noted that about 13 percent of that total is untreated sewage -- more or less during any given overflow depending on how fast the rain falls and how dry it had been prior.
And in some places, such as the stagnant Gowanus, the rain-flushed sewage tends to stick around for a while -- acutely evident on this sunny August canoe ride.
"If people knew of the massive quantities of untreated sewage going into our waterbodies, I think they would be surprised," said Judith Enck, regional administrator for the U.S. Environmental Protection Agency region that includes New York. "I think most people around the country don't realize how serious this problem is. By definition it's underground, so they don't see it."
Of course, many people have seen, smelled or even felt its effects. Every year, 1.8 million to 3.5 million Americans get sick after contact with recreational waters polluted by sewage, according to the EPA. Children are particularly vulnerable to contamination often undetectable by sight or smell. And while the most common ailments are gastrointestinal, the risks don't end there.
"Any pathogenic organism present within the population is also present within the sewage," said Andy Juhl, a marine biologist at Columbia University's Lamont-Doherty Earth Observatory in New York. "So, the sky is the limit."
What's more, CSO's don't just carry sewage. "Everything on a city street comes washing through, including toxic chemicals," said Enck. Seafood and drinking water may also become contaminated.
Despite how bad it may sound, overall water quality in the U.S. has improved significantly in recent decades. People are reclaiming urban waterways to swim, to fish, to kayak. New York City hosted its first annual Ironman Triathlon this summer -- although the swim leg was nearly cancelled due to a sewage discharge along the Hudson River.
"Forty years since the passage of the Clean Water Act, we've made tremendous improvements in water quality throughout New York Harbor," said Angela Licata, the city's deputy commissioner for sustainability, highlighting the October anniversary of Clean Water Act. "Water quality is the best it's been in 100 years."
"We have in fact stopped a lot of the traditional sources of pollution," added Lipscomb, referring to environmental battles to halt the toxic dumping by oil companies, cement manufacturers, beer distributers, even chicken processors along the Gowanus and other New York City waterways. (He recalled once spotting blood and feathers coming out of an outflow.)
Much of that toxic legacy remains layered beneath the water in the sediment, under a coat of sewage, and is marked for removal thanks to the Superfund designation Gowanus received in 2010.
"But after the Superfund effort, there are still gonna be sewers," said Lipscomb. And that brings the ultimate problem much closer to home: our bathrooms.