The goopy oil and sticky tarballs that once tainted Florida's sugar-white beaches have been thoroughly cleaned up, and even the layers of buried oil beneath the sand are gone, according to a new study by University of South Florida scientists released Tuesday.
However, they still found residual oil contamination on those beaches, detected by using ultraviolet lights.
And the way the beach was cleaned left the beaches looking slightly dirtier than they were before the spill, although spring break partiers probably won't notice. Getting it back to its completely pristine prespill conditions will still take years, however.
In their National Science Foundation-funded study, geologists Ping Wang, Rip Kirby and Jun Cheng found little to no visible oil on the surface, below the sand or in the swash zone — where waves wash up onto the beach and typically deposit seaweed and debris. The areas they surveyed last month stretched from Panama City Beach west to Dauphin Island, Ala.
"We found that most of the small surface residual tarballs on the beach were removed or further pulverized to sizes that cannot be identified with untrained eyes," their report says. "The beaches appear to be in similar condition as before the spill, except the massive temporary tire/tilling tracks" from the cleanup machinery.
The study, however, did not include looking for tar mats several inches thick reported to be submerged offshore, Wang noted.
It also didn't examine other aspects of the spill, such as a recent bloom of harmful algae that appeared to feed on the bacteria that had gobbled up the oil, Kirby said. Such blooms are rare in February, when the Gulf of Mexico is still cool from winter, he said. It could be a harbinger of a far larger and nastier bloom this summer, he said.
After the Deepwater Horizon rig exploded April 20 and began spewing oil into the Gulf of Mexico two days later, crews hired by BP cleaned the Florida beaches that were contaminated by the spreading oil spill.
However, the USF geologists who toured the beaches in June documented thick layers of oil buried inches beneath the sand by wave action. The beaches that had been "cleaned" by BP remained contaminated when oil sheets were chopped into tiny tarballs.
When they returned in August, scientists found conditions still the same. Since then, however, cleanup crews have subjected the beaches to a more "aggressive" mechanical cleanup that local residents came to call "dig-sift-refill," Kirby and Wang said.
The machines actually dug up the sand and shook it through a sieve, straining out the tarballs but mixing together the remaining contaminated and uncontaminated sand, Wang said.
As a result, Kirby said, "the sand is a shade darker." But only longtime Florida beachgoers are likely to notice the difference.
"Is it perfect like it was on April 19, before the spill started? No, it's not," Kirby said. "It will take time for bacteria to eat" the remaining microscopic oil particles — perhaps as long as five years.
In the meantime, he said, the possibility of toxic effects from those microscopic particles is fairly remote.
"You probably get more exposure filling up your gas tank than sitting on a beach," he said.
A separate USF investigation is examining the spill's effect on the small creatures whose habitats include the beach and the swash zone, and might have been affected by the cleanup.
Meanwhile, federal officials have announced that they are launching a 10-year study of the health effects of the spill on 20,000 of the workers who were involved in the cleanup — the largest such health study ever conducted after a spill.
Craig Pittman can be reached at firstname.lastname@example.org.