WOODS HOLE – Cape Cod is one of the top areas in the world for marine mammal strandings. The animals are sometimes loaded with parasites or are sick. But, despite a long history of pollution in our coastal waters, the toll pollution takes on sea creatures has been harder to establish.
In a study, recently published in the journal Environmental Pollution, Eric Montie, a University of South Florida scientist who did most of his research while a doctoral student at the Woods Hole Oceanographic Institution, found high levels of man-made chemicals in the brains and fluid surrounding the brains of marine mammals.
Scientists have known for a while that dangerous compounds like the pesticide DDT, the insulating material PCB (polychlorinated biphenyls) and the flame retardant PBDE (polybrominated diphenyl ethers) accumulate in the fatty tissue of mammals, particularly top-of-the-food-chain predators that eat chemical-laden prey.
They are also passed on through milk from mother to calf.
Although the compounds are very stable and resist being broken down within animals, studies have shown metabolized forms of these compounds in the plasma of dolphins and polar bears, and the blood of Pacific killer whales. While prior research on these chemicals had focused on their role as carcinogens or as hormone disrupters, Montie wants to discover their effects on brain development.
“People had not looked at the brain,” Montie said last week.
Montie theorized that while most contaminants are fat soluble, some become more water soluble inside animals and could possibly be able to bind to a thyroid hormone protein and pass into the central nervous system.
Working with the Cape Cod Stranding Network, Montie went to marine mammal strandings in 2004 and 2005 and retrieved the freshly dead or euthanized carcasses of 10 dolphins and a young gray seal. He used a magnetic resonance imaging machine to capture a detailed picture of their brains, to establish a baseline for future research on how chemicals could be affecting their neurological development.
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