ST. AUGUSTINE -- An announcement last week that bacterial
contamination will close between 10 and 15 percent of southern
St. Johns County's shellfish beds has raised questions about
where the pollutants are originating and what can be done to
protect the resource.
In testing the Intracoastal Waterway, environmental managers
have identified increasing concentrations of fecal coliform, a
bacteria found in human and animal waste. Now, they want to
bolster that testing to better understand what is behind the
Fecal coliform is a potential carrier of pathogens that can
cause infections or other illness in those who eat
And while the waterborne levels of the bacteria are nowhere
near the levels that would restrict activities like swimming,
they are a cumulative problem in shellfish. Shellfish act as
super filters, processing huge amounts of water in search of
food, then retaining bacteria like fecal coliform.
In Florida, shellfish beds are being slowly invaded by the
contaminants that render the delicate meats in oysters, clams
and mussels inedible. Around the state, about 1 percent of the
beds are lost each year, say state environmental monitors.
For example, shellfishing in Duval County has been closed
since 1993. There are no areas open in Nassau County. In fact,
between the Georgia border and Volusia County, only St. Johns
County has waters approved for the harvests.
Chris Benjamin, intergovernmental coordinator for St. Johns
County, said that to find answers, agencies including the
county, the St. Johns River Water Management District and the
state Department of Environmental Protection are working on a
plan that would increase water sampling.
In addition to closing the waters to shellfish harvesters who
have long used the waters for a livelihood, the increasing
contamination points to a larger issue, Benjamin said.
"It's a pretty good indicator of water quality," said
Benjamin. "That's why it is important."
Stormwater runoff, septic tanks and boaters who dump waste
into the water have been identified as sources of the bacteria
in waters around the Matanzas Inlet. But because massive
development has not hit areas like southern St. Johns County,
environmental managers are perplexed about why contamination is
Benjamin said agencies could take over some of the testing to
allow the state to begin sampling untested waters like those to
the south in Flagler County.
Intensive water surveys conducted throughout rising and
falling tide cycles could be used to build computer models that
would give a clearer picture of what is happening, Benjamin said.
"We would probably jump into the hot spots we know of," he
said. "We'd try to identify what we call the plume."
That plume, a footprint of where bacteria is at certain times
of a tide cycle, could help identify the sources of the
"This is a creative approach and I am looking at it
positively," said Robert Thompson, an environmental
administrator with the Department of Environmental Protection.
But, he said, there is a problem with expense.
The same approach was considered in Hillsborough County but
abandoned because of cost, he said. …