From Toilet To Pond: Suburban Ecosystems Are Full Of Human Waste

Jan 16, 2018

Scientists at Yale took a look at the diet of tadpoles in suburban ponds, and they made a discovery that – fair warning – is a bit gross. It turns out human waste plays a much larger role in the suburban ecosystem than we thought.

Scientists went to a pond in Madison, Connecticut, not too far from Yale. They found these tadpoles live on algae that’s made primarily of human waste.

Max Lambert, one of the authors, says this unwholesome cycle begins with the septic tanks in our backyards and the sewer lines under our feet. “Septic systems are designed by their very nature to release fluid after so much time. Whatever comes out of it has a good chance of leaching into the water underground and that kind of flows into these ponds.”

That waste turns into bacteria, fungi and algae. And it’s that algae that makes up most of a typical wood frog tadpole’s diet. And of course, you are what you eat – so that means these tadpoles are pretty much made of human waste themselves.

Lambert says, believe it or not, that might not necessarily be a bad thing. “If anything, because they’re eating more algae, we kind of consider algae to be a higher-quality food resource, so in some ways you might argue there’s more robust tadpoles coming out of these suburban ponds.”

It’s not necessarily a good thing either. Sometimes tadpoles are also eating things like pharmaceuticals that don’t break down in our waste. Scientists have found estrogen and other hormones in suburban ponds.

“Tadpoles metamorphose – they grow four legs, they crawl out of the pond, they crawl off into the landscape. So in some ways we’re kind of fertilizing our suburban landscapes with our own wastes.”

Those frogs will get eaten by birds, snakes, raccoons and all other manner of animals, spreading our byproducts far and wide in the ecosystem.