Here’s something to ruin your summer. The sand at the beach might be filled with fecal matter

Scientists have found the sand at a beach can have 100 times more fecal bacteria than the water. They’ve known about it for a decade, but apparently no one thought to alert the public until now.

It’s a combination of everything from bird poop, sewage runoff, and dirty diapers that aren’t disposed of properly. Little kids at the beach go “boom boom” in the ocean more than you might expect.

A new study at the University of Hawaii looked at why there’s so much fecal matter in beach sand compared to the ocean, and found the bacteria takes much longer to decay when it’s in sand than it does in saltwater.

The good news is it probably won’t kill you. But if you come into contact with enough of it, you can end up with stomach pains and diarrhea.