"SAN FRANCISCO, Calif. – In a shallow arm of the bay, where Pacific tides cause hardly a ripple, hundreds of harbor seals lounge, mate and bear young. With placid expressions on bewhiskered faces and bulky bodies reclining on shorelines, the seals belie a disturbing burden they carry."
"Living on the edge of a metropolitan hub, these seals are under scrutiny by scientists. There’s a mystery afoot in San Francisco Bay: A manmade chemical, pulled from production 12 years ago, is still turning up at high levels in the seals.
Once the prime ingredient in Scotchgard, a chemical known as PFOS has remained elevated in these harbor seals even though it has declined in sea birds that share their fish diet."