The Gulf of Mexico receives 10 million pounds of chemical pollution each year, some of which mimics human hormones. These pesticides, herbicides and fungicides can interfere with sexual function in reptiles and amphibians. The effect on humans is unknown.
"You can see we have some disturbing trends," said chemist Julia Lytle, who has worked with her husband, Tom, to study pollutants in sediments on the Coast since the early 1970s.
Lytle spoke Wednesday as part of a Sustainable Fisheries lecture series sponsored by the Gulf Coast Research Laboratory in Ocean Springs.
The Lytles' work has revealed that toxic chemicals locked in ocean sediments remain potent for a long time. PCBs, DDT, TBTs and other toxic chemicals degrade slowly.
"It's around and it's hard to get rid of," Lytle said.
Even common detergents cause damage by making the water cloudier in the same way they lift dirt from soiled clothes. Detergents also might disrupt the bodily functions of animals and humans.
"A lot of detergents act as endocrine disrupters, which can mimic a hormone," Lytle said.
Pollutants entering the Gulf include hydrocarbons from petroleum, PCBs from manufacturing and combustion, pesticides from farming, heavy metals and toxic compounds used in antifouling boat paint.
Another speaker said that controlling sewage pollution is crucial to the Gulf's $50 million oyster industry. Seven percent of the Gulf oysters are harvested from Mississippi waters. More oysters could be harvested if sewage treatment systems were improved.
"We're kind of holding our own," said Tom Herrington, assistant director of the Gulf of Mexico Program.
A virulent bacteria, vibrio vulnificus, causes about 18 deaths a year nationwide in people who eat raw oysters, but hundreds of stomach illnesses are caused when human waste contaminates oyster reefs.
Mississippi's tightly managed oyster program, however, has prevented vibrio vulnificus deaths and virtually all other illnesses.
"They are some of the best oysters in the world," Herrington said.