Piney Point spill ‘diluted’ in Tampa Bay, but USF researchers point to unknown impacts
The harmful nutrients that entered Tampa Bay following the discharge of 215 million gallons of wastewater at Piney Point have mostly diluted, according to University of South Florida researchers.
In April, a leak at the former phosphate processing plant forced the Florida Department of Environmental Protection to approve an emergency release of water that could pose a threat for the environment. In a Monday press conference, scientists said many of those impacts are still unknown.
“Although the residence time of water in Tampa Bay is on the order of months and the bay flushes slowly, the discharged water seems to have been diluted pretty quickly,” said Bob Weisberg, a physical oceanographer at USF who put together a forecast model that predicted the flow of the nutrients last month.
An updated model depicts much lower nutrient levels throughout Tampa Bay, lending credence to FDEP’s idea to pump the nutrient-rich water into the bay where the deep channel could minimize the environmental danger.
Since April 7, USF has sent crews to the area to collect water samples. While there was a spike in nutrient levels, researchers said those effects were localized, not widespread.
“The area in the immediate vicinity of Port Manatee was subject to a spike in nutrient concentrations and a corresponding increase in phytoplankton abundance,” said Tom Frazer, dean of USF’s College of Marine Science.
Other concerns that researchers are keeping tabs on include impacts to marine life and seagrass beds, as well as concentrations of contaminants in ocean water, sediment and fish.
“An obvious question that people have is seafood safety,” said Steve Murawski, a fish biologist and professor at USF.
Murawski said fish appear healthy in the area of the spill, and noted that the Florida Department of Health has not issued any fish consumption advisories for the area. However, researchers are still in the process of checking local fish populations for elevated heavy metals, nutrients and radiological contaminants, Murawski said.
Another feared outcome of the discharge was a major toxic algae bloom, such as red tide. Algae organisms are known to feed off of the nutrients, especially nitrogen and phosphorous, in Piney Point’s wastewater.
A short-lived, non-toxic algae bloom did occur in the direct area of the spill in April. But so far, no harmful algal blooms have been documented there. And researchers don’t see a clear link between the discharge and low levels of the red tide organism that have been present in lower Tampa Bay in recent weeks.
“There are low to background concentrations of the red tide organism in the southern part of the bay right now, but I think it’d be premature to draw a cause and effect relationship between those two things,” Frazer said.
Frazer said the current research efforts will help scientists answer important questions about how an ecosystem like Tampa Bay responds to a major wastewater discharge.
This story was originally published May 26, 2021 at 5:00 AM.
