Two women are seen at the waterline along Ben T. Davis Beach Thursday, July 25, 2013 in Tampa. The Hillsborough County Health Department issued an advisory for three beaches July 24 after testing revealed excessive levels of enterococci bacteria. The advisory for Bahia Beach, Ben T. Davis, and Picnic Island Park beaches will remain in effect until re-sampling indicates the water is within the satisfactory range, health officials say. The beaches will be retested today. CHRIS URSO/STAFF
TAMPA - The sign posted on the shoreline at Picnic Island Park warned people that swimming could pose a health risk.
Amy Dickinson didn't notice the sign as she unloaded a personal watercraft from the back of her truck.
"The water looks the same," Dickinson, 34, said with a shrug. "It's just a little darker."
When she was told the area was closed to swimmers because of high levels of bacteria, Dickinson was surprised.
"OK, that actually concerns me," she said. "That kind of scares me."
The Hillsborough County Health Department last week issued advisories for two other popular recreational areas along Tampa Bay - Bahia Beach and Ben T. Davis Beach - because of high levels of enterococci bacteria in the water.
The advisory remains in effect today and won't be lifted until water samples show bacteria has decreased to a safe level, said health department spokesman Steve Huard.
Scientists will test the waters again this week.
There is no big mystery how the bacteria gets into recreational waters, said Michael Muszynski, associate dean for Florida State University's College of Medicine.
"There tends to be spikes in contaminant counts when there's lots and lots of rainfall," said Muszynski, a medical doctor who studies the spread of infectious diseases. "It's typically caused by storm-water runoff."
Hillsborough County has had plenty of rainfall in July.
As of Sunday, Tampa has been doused with 7.25 inches of rain, with is more than average for the entire month of July, said Robert Garcia, forecaster for the National Weather Service.
Muszynski said bacteria also can spread by overflowing septic tanks and effluent from sewage or water treatment plants. The bacteria is found in human and animal fecal matter.
Picnic Island Park, a waterfront expanse south of Port Tampa on Tampa's Interbay Peninsula, has a dog park where canines are allowed in the water. Ben T. Davis beach is a stretch of sand and gentle waves on the south side of the eastern Courtney Campbell Causeway.
Dickinson, from St. Petersburg, said she used to frequent a boat ramp off Gandy Boulevard in Pinellas County but made Picnic Island Beach one of her prime destinations because of one factor: "The water just seemed cleaner over here," she said of Picnic Island. "We haven't had any problems before. Hopefully we still don't."
As for the enterococci bacteria itself?
"They're just markers," Muszynski said. "They indicate that there could be other pathogenic organisms in the water that cause disease."
The diseases run the gamut from mild cases of vomiting, diarrhea and respiratory ailments to more serious cases of salmonella, dysentery, cholera and typhoid.
Enterococci is found in salt water and E Coli bacteria is found in fresh water.
There is no procedure to remove the bacteria from the water, but given time the organisms simply die off, Muszynski said.
Samples taken from Picnic Island Park's beach last week showed 105 colony-forming units of enteroccoci bacteria per 100 milliliters of water, Huard said.
That means there are about 105 individual bacterial microbes in that amount of water which can produce separate colonies of more bacteria, according to the state health department.
The Environmental Protection Agency's recommended standard is no more than 104 colony-forming units of the bacteria per 100 milliliters of water.
This has been the third advisory about poor water quality posted this year at Picnic Island and the first for Bahia Beach, according to the state Department of Health's Healthy Beaches Program. Ben T. Davis Beach has had five instances of poor water quality this year.
"We test the water in those beaches every week," Huard said.
North and south portions of Picnic Island Park had advisories or closings posted on 65 days last year, according to a water quality study by the National Resources Defense Council. The council is an environmental advocacy group based in New York.
Portions of Ben T. Davis Beach had a total of 119 advisories or closings last year; Bahia Beach had 19, the study reported.