Besides such "legacy" pollutants lingering in sediments, a host of pharmaceuticals, personal care products and other hormone-mimicking chemical compounds have been detected in the outfalls of wastewater treatment plants and in fish sampled at various points around the bay. It is unclear, though, how widespread they are or what effects, if any, they're having on wildlife.
There has not been a great deal of research on the potential effects of contaminants on wildlife in the bay, said Mary Ann Ottinger, a professor of animal sciences at College Park and Lazarus' doctoral adviser. There have been studies of fish, but few involving birds such as ospreys.
"If we can detect these effects in ospreys, what effect are they having on other wildlife and humans?" asked Lazarus, who is working part time for the geological survey while completing her dissertation.
Back River is a good place to check because it is among the bay's least healthy tributaries, according to the most recent ecological report card issued by the University of Maryland. Among other problems, Back River is impaired by nutrients, the same pollutants that spark algae blooms and dead zones in the Chesapeake Bay.
One of the leading sources is the Back River sewage treatment plant, the state's largest, which processes household waste from 1.3 million residents in Baltimore and Baltimore County. The scientists checking the osprey nests say they have smelled ammonia — a nitrogen-rich ingredient of human waste — on the river near where the city-run plant discharges its treated wastewater.
Kurt Kocher, a spokesman for the city's Department of Public Works, said the facility meets all regulatory limits and is to receive a major upgrade in the fall. The plant's 466-acre site is home to ospreys and bald eagles, he noted.
Storm water washes trash and contaminants into the river from streets and parking lots. And two old toxic waste dumps on the federal government's Superfund cleanup list have leached pollutants into the river.
Watts, the William & Mary biologist, said the federal study is increasing what scientists know about the effects on wildlife — and by extension humans — of the contaminants that seem ubiquitous in the environment.
"There's an entire aquatic food chain," Watts noted, "some of which we eat."
The state has warned the public to limit consumption of some fish from Back River, such as brown bullhead and white perch, and to avoid eating other bottom-feeders caught there, such as channel catfish and carp. River sediments are still tainted by a long-banned termite pesticide, chlordane; by PCBs; and by flame-retardant compounds.
"It's getting a lot of trash; it's getting a lot of pollution and runoff," said Molly Williams, project manager for the Back River Restoration Committee, a community group that has been working for several years to clean up debris from the bottom and shoreline. "It's visually evident after you get a rain event. Pair that with pollution you can't see, it has to be devastating to ospreys."
Tony Kotecki, who has lived downriver from the treatment plant for 25 years, said he's seen more water birds of all types in recent years, including ospreys and bald eagles, and believes that's a sign cleanup efforts are working. The river is "getting way better," he said, though he acknowledges it still has a ways to go.
He built a nesting platform on his pier to encourage ospreys to make the river home, he said, and it did attract a pair of birds. But after eating fish, he recalled, they flew off.