PBDEs in Oysters in Matanzas River

Banned element found in oysters
Monday, April 20th, 2009 at 12:10 am by Beth Romanik

By STEVE PATTERSON
Morris News Service

A chemical compound that’s banned in some countries has turned up in surprising levels in oysters in a nearly untouched St. Johns County waterway.
The discovery of the fire-retardant chemical in the Matanzas River near Crescent Beach is puzzling, but whether it’s really meaningful remains to be seen, said a scientist who works in the area.
“It’s a concern, but it’s not something that’s a panic situation,” said Michael Shirley, director of the Guana Tolomato Matanzas National Estuarine Research Reserve. He said he’s not sure why the chemical might be found there and has asked federal researchers who reported the levels to recheck their findings.
“I could understand if we had a drainage going into that area from a landfill,” Shirley said. “This area is fairly pristine. … It’s not industrialized at all.”
The substance, called polybrominated diphenyl ethers (PBDEs), has a similar chemical structure to polychlorinated biphenyls (PCBs), which were banned decades ago as a health hazard.
Recently, federal researchers studied shellfish and sediment samples from shorelines around the country to survey PBDE levels nationally.
Their study, released this month, reported a high PBDE level in oyster tissue in the Matanzas near the Verle Pope Bridge on State Road 206. That’s one of few places in Northeast Florida where oyster harvesting is still allowed.
A smaller amount was also found in oysters from Chicopit Bay, where the St. Johns River meets the Intracoastal Waterway in Jacksonville.
The research by National Oceanic and Atmospheric Administration scientists is apparently the first national survey of PBDE levels in sediment and sea life. There is no standard for how much of the chemical is safe in oysters.
Oysters can be a barometer for a lot of factors affecting a river, said Shelley Beville, a coastal ecologist who has been studying oysters locally. She was not part of the NOAA project.
Because they anchor themselves in one spot and sift up to 50 gallons of water daily for food, oysters hold years of information about water conditions in the place they’re found, said Beville, who works for the Nature Conservancy.
Their tissue shows how some chemicals accumulate in flesh, and that tissue also is food for fish, crabs and raccoons, whose bodies can absorb the same chemicals.
PBDEs worry scientists because some research suggests the compounds cause liver, thyroid and behavioral problems in animals and might affect people, too. Once widely used, the chemical has been banned from products sold in Europe and most forms of PBDEs aren’t made in this country anymore, either.
The NOAA research was meant to measure how much of the chemicals are still lingering on coastlines.
The NOAA study found high PBDE concentrations in oyster samples from four places in Florida. Matanzas River had the lowest of those readings, at 322 parts per billion. The higher readings were found in Cedar Key, Apalachee Bay and Charlotte Harbor.
Tests on oysters in 28 other spots in Florida and three in Georgia found lower levels of the chemical.
Because the researchers only had one set of PBDE tests from Matanzas, there’s no way to know whether PBDE levels have been rising over time, falling or holding steady — any of which would help find meaning in the readings, Shirley said.
The river has been part of a NOAA project to measure other chemicals in water and oysters for years, and it’s usually considered a very clean, healthy waterway, he said.
It’s possible something unusual happened in the river just before the test, Shirley said, or even that something happened in the lab that affected the results. He said he asked NOAA scientists to look again at some of their findings but said there are lots of measures in place already to catch any mistakes.
The amount in oysters from Chicopit Bay, 153 parts per billion, was several times greater than most of the Florida samples but was far short of what the researchers considered a high reading.
Finding man-made chemicals in the bay isn’t surprising, though they’re usually not too heavily concentrated, said Richard Bryant, chief of resources at the Timucuan Ecological and Historic Preserve.
There are houses and roads on the East Arlington shoreline, he said, and “you’re getting some runoff that is staying in that little bay.”
The National Park Service, which manages the Timucuan, tested water around the preserve last summer and found Chicopit Bay was in fairly good shape, he said.
“There are some minor concerns there” in the bay, he said. “It’s not great; it’s not bad.”
The NOAA research found no PBDEs in the sand and sediment of either the bay or the Matanzas, something that held true for about half of the Florida sites where sediment testing was done.