TAMPA, Fla. — Contamination in local waters seems to have declined since the discharge of polluted water in early April from the old Piney Point fertilizer plant site into Tampa Bay, researchers said Monday.
Early results show the effects of the release were relatively contained in an area of lower Tampa Bay, according to scientists at the University of South Florida College of Marine Science. But many questions remain about the consequences of the spill on fish, seagrasses and what — if any — harm might emerge over time.
“We’re fairly fortunate that we didn’t see a long-lived, widespread effect on that ecosystem,” said Thomas Frazer, dean of the college.
Researchers from the university began taking samples from Tampa Bay in early April, as the release was ongoing. Early on, they reported an bloom of a non-toxic form of algae, immediately around Port Manatee. That has since dissipated, they said Monday, along with concentrations of nutrients such as nitrogen and phosphorus in the bay. Over time, wastewater was flushed and mixed into the bay, reducing concentrations. Today, the scientists believe levels are more in line with historic averages.
Researchers are still awaiting lab results for monitoring metals such as cadmium, nickel and cobalt that could have been added to the bay off Piney Point. They are also still analyzing samples taken from fish to understand how contamination might have affected marine life. Steve Murawski, a marine ecologist, said after the spill he did not see any fish in the area with lesions or obvious signs of harm.
“Fish were relatively abundant off Port Manatee,” he said.
About 215 million gallons of polluted water was pumped to Tampa Bay because of the crisis at Piney Point. State environmental regulators allowed the discharge to reduce pressure, fearing a leak in a plastic-lined reservoir at the property would break open, causing a collapse and catastrophic flood.
Crews released the water through Port Manatee. From there, it was carried into the greater bay, bearing high levels of nutrients. Clean water advocates said that waste, like fertilizer on land, could spur growth in algae — some of which are harmful.
The discharge was equal in nitrogen to about 100,000 bags of hardware store fertilizer being dumped into the estuary over several days, according to one estimate from the Tampa Bay Estuary Program’s director.
Port Manatee sits between a couple of aquatic preserves, Cockroach Bay in Hillsborough County and Terra Ceia to the south.
Sampling over the last several weeks has detected very low to low levels of the organism found in Red Tide around Lower Tampa Bay, according to the Florida Fish and Wildlife Conservation Commission. Those results do not indicate a full-on bloom. Sustained Red Tide is a major concern, because it can cause large fish kills, breathing trouble for people on the shore and shellfish harvesting closures.
The Piney Point discharge alone would not cause Red Tide to turn up in Tampa Bay, researchers have said, but extra nutrients threatened to help fuel a bloom.
The University of South Florida scientists said they will continue taking samples and analyzing the results over coming months.
“We should not be walking away from this,” Murawski said.
Frazer, the dean, said the Piney Point situation has revealed the importance of having consistent monitoring of Tampa Bay, so that scientists have a decent baseline by which to measure the effects of pollution.
“We need to better understand how the ecosystem in the bay responds to a pulse event like this,” he said.
