As a baseline, New York City churns out around 1,200 tons (2.4 million pounds) of biosolids (poo and pee) each day. The average bowel movement for a westerner is around .25 pounds (pssst, eat more fiber), and the average person poops once a day (to say nothing of the common phenomenon of runner's diarrhea). So it wouldn't be nuts to assume that most of the runners made a deposit. If all 50,000-plus did, that's 12,500 pounds of poop before we add in spectators. Another way to look at this, if we're not going to discriminate against urine, is that porta potties can generally accommodate 60 gallons of various wastes. That's about 500 pounds of water, and, well, we hope your poop isn't that watery. If we're conservative and assume that each of these johns were at least a quarter full, that comes out to more than 250,000 pounds of extra waste (again, we hope a gallon of your poop would weigh more than a gallon of water, but we're not your doctor). Either way, the marathon poo is a veritable drop in the bucket for the Big Apple. But that's still a lot of crap to deal with, and you might wonder where it gets carted off to.