Chemicals in Indian River Lagoon affect dolphins health in several ways!

Scientists have discovered chemicals used to fireproof plastics and products in the blood and blubber of bottlenose dolphin in the Indian River Lagoon.

They don't yet know for certain how the chemicals got there, but they suspect they could be playing a role in the new diseases, such as herpes, that are attacking the marine mammals.

"The data suggests at this point that these flame retardants suppress a part of the immune system that makes antibodies," said Greg Bossart, one of the researchers who made the discovery. "There's a potential of opening up these animals to a Pandora's box of diseases."

Bossart and his colleagues found flame retardants called polybrominated diphenyl ethers or PBDEs in tests of dolphin in the lagoon and in Charleston Harbor, S.C. They measured mean levels of total PBDEs in lagoon dolphin at about 1,500 parts per billion in fat tissue, more than three times the highest levels found in humans, 500 parts per billion.

Bossart said the research hasn't determined what level of PBDEs has significant effect on dolphin or human health.

"What we do know is that we found these chemicals," he said. "My concern is that we're documenting these emerging diseases in bottlenose dolphins."

For example, when the dolphin health study began in 2003, his research team found no oral or genital tumors on lagoon bottlenose dolphin. Last year, 47 percent had tumors.

"There's something that's going on that's allowing this disease to manifest itself," Bossart said.
The team plans to publish its results in coming months.

Testing

In the third of five years, the study compares the health of lagoon bottlenose to bottlenose in Charleston Harbor. Most of the $1.25 million for study--scientists have spent about $800,000 so far -- comes from sales of Florida's dolphin license plates.

Bossart and his colleagues drew blood and plasma samples from 113 bottlenose dolphin -- ages 3.5 to 28 years old -- in the lagoon and harbor in summers 2003 and 2004.

He said the South Carolina dolphin tested at higher levels of PBDEs than lagoon dolphin likely because the area has more industry.

Bossart said the PBDEs may be linked to the increased rates of tumors caused by viruses, stomach ulcers from bacterial infections and other conditions afflicting dolphin.

But the finding also raises concern about whether humans may be at risk.

Studies show PBDEs don't break down easily and may be linked to cancer and birth defects, including ones that affect brain and thyroid development.

"It's not readily metabolized by the body," said Erin Hughes, marine biologist and aquatic toxicologist at University of Florida's Center for Environmental and Human Toxicology. "They will biomagnify in larger organisms. They stick to fat and blubber."

Human impact

PBDEs are widely used flame retardants rising rapidly in human tissues. Studies have found them in blood, breast milk and fat. They're blended into plastics and foams used for computer casings, carpet pads and foam cushions on chairs and couches.

A California ban on two forms of PBDEs takes effect later this year.

People can take in the chemical by contact but mostly ingest it from foods. Salmon and catfish typically have the highest levels among fish, tilapia the lowest, according to studies by the U.S. Environmental Protection Agency. Pork, sausage and bacon can also have high levels.

PBDEs settle in sediments, then make their way up the food chain to marine mammals, fish and bird eggs. They run off in stormwater and seep up from contaminated groundwater and sewage.
"Wastewater's probably the most likely source of this," said John Windsor, a professor at Florida Tech's department of marine and environmental sciences. "It's hard to say exactly that these things are causing the effect, because there might be something else in the water we're not looking for causing the effect."

Health crisis

Windsor said PBDEs have not yet been found in the lagoon.

"It's too low in concentration, so it's hard to measure," he said. "We can analyze things at very low concentrations, we just don't know what the effects are."

The PBDE discovery adds to a growing list of chemicals and environmental stresses Bossart said might be clues to emerging dolphin epidemics.

"Our data certainly suggests that these animals are on the edge of a health crisis," he said.