I have a photo taken in Manhattan, on a block where there were a lot of people walking their dogs. The sunlight is reflecting off the sidewalk, and a woman is

I have a photo taken in Manhattan, on a block where there were a lot of people walking their dogs. The sunlight is reflecting off the sidewalk, and a woman is picking up her dog's shit. The place where she has picked up the shit has a spot remaining, and you can see, all over the sidewalk, similar spots. Not just a few, I mean all over the sidewalk. As I took the photo, I wondered, how much of that shit is being tracked into everyone's homes?