To learn more, Keller's lab is looking to the U.S. Pacific, where sea turtles haven't been tested for contaminants.
One hypothesis is that chemicals might be responsible for a virus, called fibropapillomatosis, that promotes the growth of tumors in the Pacific’s sea turtles. If chemicals suppress their immune system, the virus could grow into tumors.
But so far Keller has not found any evidence of that. "Our pilot study is showing that it does not look like organic contaminants are the trigger or cause," she said.
Since the 2001 phaseout of PFOS, levels have decreased in many marine animals. From 2000 to 2008, PFOS declined by 20 percent annually in loggerhead turtles tested near Charleston, S.C. Yet PFOS and its precursors remain in older consumer products, and sea turtles remain contaminated.
"PFOS is still out there in consumer products. It's still on couches and carpets," Keller said. "Eventually those things are going to go to the landfill. We need better ways to dispose of them."
This article originally ran at Environmental Health News, a news source published by Environmental Health Sciences, a nonprofit media company.