Credit: Screenshot | South Portland Parks and Recreation

South Portland Parks and Recreation said they placed about 300 flags in Hinckley Park to mark where people didn’t clean up their dog’s poop.

Park officials said the waste ends up in the ponds, which connect to Trout Brook and, ultimately, wash out to Casco bay without treatment.

Pet waste contains bacteria that threaten the health of animals and people, especially children. Pet waste also contains nutrients that encourage excess weed and algae growth. Excess nutrients are a major cause of water quality decline, according to park officials.

“Do your part by keeping a close eye on your pet, especially when you first arrive. If you see a pile that isn’t yours, pick it up anyways. Everyone missed a pile from time to time so pay it forward when you spot a poop,” South Portland Parks and Recreation said in a Facebook post.

Park officials said if people can join them in a cleanup effort from 9 a.m. to noon April 20.