The Lincoln Memorial and the reflecting pool on the Mall. (Matt Campbell/European Pressphoto Agency)

The Lincoln Memorial’s Reflecting Pool will be drained and cleaned next week after a waterborne parasite killed several ducklings, officials said.

Since May 20, about 80 ducklings have been found dead in the Reflecting Pool, and necropsies showed the likely cause of death to be parasites that grow in snails that live in the water, the National Park Service said in a statement. Chemical treatments cannot kill the parasites and snails, so the water must be drained and cleaned, the statement said.

Though the risks of a person contracting the parasite at the Reflecting Pool are “extremely low,” according to the statement, those who come in contact with it could get cercarial dermatitis, more commonly known as swimmer’s itch, which causes a skin rash.

The draining, which will take two days, and cleaning will begin on Sunday, the Park Service said, and refilling will begin June 16.

Mike Litterst, a spokesman for the National Park Service, said the Reflecting Pool, with a capacity of almost 4 million gallons, has been drained and cleaned before, but not for this reason. It’s not clear why the parasite killed the ducks this year, he said, but the deaths might be related to a string of 90-degree days in May that somehow made the parasite more deadly.

“That’s something we’re trying to figure out,” he said. “We may never know.”