In my book, I claim America gives a porcelain send-off to 108 million pounds of poop every single day. 4.5 million pounds an hour. 39.4 billion pounds a year.

Now I’ll prove it.

Or, rather, I won’t. Because my research uncovered a shocking gap in scientific knowledge: we don’t actually know how much we poop.

Here’s what we do know: there are 300 million Americans. In 1996, the EPA estimated that 72% of us are served by America’s 16,000+ publicly-owned sewage treatment plants. Assuming that number is still accurate, that’s 216 million people today. Those of you who are good at math have already figured out where this is headed: 216 million people, 108 million pounds — a daily per-capita of a half-pound of cable laid.

But that’s an educated guess. Because, as it turns out, there are no definitive figures. In his book Nanomedicine, Dr. Robert A. Freitas Jr. cites three studies in putting his daily figure at 100-200 grams — that is, .22 to .44 pounds a day. A 1992 study in Gastroenterology found an average of 106 grams a day among 220 UK residents, but with the caveat that “data from other populations of the world show average stool weight to vary from 72 to 470 g/day.” The Merck Manual says that Westerners grunt out 100-300 grams a day. But in the very next breath, Merck says that “generally, stool amount > 300 g/day is considered diarrhea” — which is ridiculous, because who defines diarrhea by weight? A two-pound bowl-curler isn’t diarrhea because it tips some arbitrary scale; nor is a sputtering blurt of rancid curry ambiguous until some formal weigh-in.

With no logical recognition of the nature of diarrhea, it’s no wonder science lacks consensus on our species’ blatting average. But Merck seemed pretty confident in its declaration, so for my book I split its figures — 200 grams, .44 pounds — and rounded up to make the math easier. Multiply by 216 million people and I got my answer. And it’s a staggering figure — the equivalent of 123 fully-loaded 747s! Of 18.3 million 14-inch iBook G4s! Of 108 million one-pound weights!

But dive down into your toilet, swim through the sewers, and emerge at the treatment plant, and you’ll discover a lot more than 108 million pounds floating through the network. Wikipedia estimates that 17% of Americans are served by on-site sanitation systems like septic tanks. Septic tanks are emptied by pump trucks, and pump trucks are emptied into the sewage infrastructure — so even those living off the sewage grid are still adding their poop to it.

(It’s just too bad we can’t use that poop for good.)

I’m sure some will question my half-pound-per-day estimate. That’s fine — I question it myself. For instance, is it even relevant to calculate a daily average? After all, while some people go three times a day, others go three times a week, and because diet and metabolism are unique to all of us, such variation in schedule is not at all abnormal. Furthermore, a high-fiber diet bumps up stool weight; those who aren’t eating their veggies aren’t bulking their poop. And poop itself is around 75% water — on hot days, when we sweat a lot, does our poop weigh less?

In other words: it took me three hours to write this article. In that time, I believe America passed 13.5 million pounds of poop.

But no one really knows for sure.

Dave Praeger is the author of Poop Culture: How America is Shaped by its Grossest National Product. Get your copy today!

With the news that North American farmers might soon endure a fertilizer shortage (also reported here), I’d like to present two completely unrelated numbers:

1. Farmers in the US use sixty-seven million pounds of nitrogen fertilizer every single day.
   
   
2. Toilet users in the US flush 108 million pounds of poop* down the toilet every single day.

Why do I call those numbers “unrelated”? After all, the poop-educated amongst us will instantly recognize that #2 can replace #1 — that human waste, when properly composted, makes excellent fertilizer. You know that humanity’s place at the top of the food chain means we’re supposed to be at the bottom, providing food for bacteria and fertilizer for plants. Can’t the poop we flush grow the food we eat? Why endure a fertilizer shortage when we’re flushing 108 million pounds of fertilizer down the toilet every single day?

The reason is that it’s not just poop and pee arriving at the sewage treatment plant.

If sewers contained only organic waste, there wouldn’t be a problem. But in addition to poop and pee, sewers contain the Drano we pour into our bathtubs and the paint we pour into our sinks. In cities with combined rainwater and wastewater sewers, they contain the oil-slicked runoff from roads and melted roadside snow turned brown from the exhaust of the cars driving past. They contain industrial and commercial waste dumped both legally and illegally. And at the sewage treatment plant, all these chemicals and metals and compounds and contaminants are concentrated with our poop and our pee into sludge.

And since it’s impossible to say what’s in the sludge beyond our poop and pee, it’s impossible to know what will happen when all those chemicals and metals and compounds and contaminants are applied to the land.

This is why we can’t just ship our sludge to the farmers and let them have at it. As smart and holistic as it would be to reinstate humanity’s place at the bottom of the food chain, it may be better to shove it all in a landfill and hope it never comes back.

I say “may” because I’m not convinced one way or the other. On the one hand, you have the EPA’s long and detailed rules regulating the use of sludge as fertilizer — they do allow it, provided you abide by a number of precautions meant to keep the contaminants from moving down into the water table or up into the crops. But on the other hand, you have essays like Abby Rockefeller’s seminal Civilization and Sludge, which argues that even with those rules, the contaminants in the sludge are going to outlive the farmers who maintain the land, and that they’re going to come back to hurt us eventually.

So even if shortages mean farmers can’t get the sixty-seven million pounds of fertilizer they need each day this spring, we can’t help them out with the 108 million pounds of fertilizer we’ll waste. Until we can figure out how to keep our sewers free from all but poop and pee, those two numbers may have to remain forever unrelated.

* I’ll be blogging about how I arrived at the “108 million pounds of poop per day” figure in the next couple of days.