UPDATED April 26, 2021 at 3:52 p.m. – PALMETTO – About half the wastewater in a leaking retention pond built into a gyp stack at the closed Piney Point phosphate plant has been pumped into Tampa Bay at Port Manatee, and the 215 million gallons are spreading.
Officials initiated the controlled emergency discharge in March to take pressure off the compromised gyp stack and avoid an accidental spill of even more of its contents after a leak was detected on March 26.
The discharge ended April 9, leaving a pollutant plume containing what the Florida Department of Environmental Protection (DEP) calls “mixed sea water.” The acidic blend of saltwater and debris from a Port Manatee dredge project, stormwater runoff and rainfall also contains “legacy process water” – wastewater from phosphate processing that carries nutrients such as phosphorus and nitrogen that can feed toxic red tide algae blooms.
Sensitive environmental areas in Tampa Bay, the Gulf of Mexico, the Manatee River, the Little Manatee River, Bishop Harbor and Terra Ceia Bay are impacted so far, according to Dr. Robert H. Weisberg, distinguished professor of physical oceanography at the University of South Florida’s College of Marine Science in St. Petersburg.
“We see obvious visible impacts of plant growth. You see water that looks rather brown, instead of water that’s normally green,” he said in a video conference, adding that it’s likely to adversely affect fish and marine plants.
A team of scientists is tracking where the plume will go, how it dilutes over time and what its effects will be, he said.
The wastewater is “sloshing back and forth” with the tides, currents and winds, causing the plume to disperse more widely, he said.
Dilution is a slow process, Weisberg said, estimating that there will be low concentrations in Tampa Bay and the Gulf as it disperses over the coming months.
The process is likely to continue until strong winds flush it out of the bay, he added.
“This time of year, we really don’t get those big (wind) events that will flush the system out, so it’s going to be with us for a while,” he said. “At least so far, we don’t see any indication of anything toxic. But when you feed a lot of nutrients, plant growth takes off, just like in your garden.”
Multiple educational institutions, governmental agencies and environmental organizations are collecting water, fish, seagrass and other samples to assess acidity, oxygen, salinity, temperature, carbon, bacteria, phytoplankton, nutrients and trace metals in the wake of the discharge. Results will not be immediate.
Water quality reports
Red tide has been detected in Manatee County in low concentrations for the first time since the Piney Point disaster.
Red tide-related respiratory irritation was reported in Manatee County, and fish kills were reported in Sarasota County to the south, according to the most recent Florida Fish and Wildlife Conservation Commission weekly report.
Environmental officials say that the nutrients phosphorus and nitrogen, which feed toxic red tide algae blooms, were present in the 215 million gallons of polluted water discharged into Tampa Bay at Port Manatee from one of the inactive Piney Point phosphate plant’s retention ponds, built into a gypsum stack.
The DEP reports that the red tide is “not thought to be a direct result of the Piney Point discharges, however, elevated nutrients have the potential to exacerbate these algal blooms, and increased sampling is ongoing.”
Low concentrations of red tide were found at Mead Point (Perico Island) in lower Tampa Bay, and very low concentrations were detected at the Rod & Reel Pier in Anna Maria, also in lower Tampa Bay, School Key (Key Royale), and the Longboat Pass boat ramp in Sarasota Bay.
Red tide produces a neurotoxin called brevetoxin that can cause respiratory irritation, coughing, and more serious illness for people with severe or chronic respiratory conditions such as asthma, emphysema or COPD, according to the Florida Department of Health. Health officials recommend that people experiencing symptoms stay away from the water, go inside to an air-conditioned space, or wear masks, especially during onshore winds.
Consuming shellfish exposed to red tide can cause neurotoxic shellfish poisoning.
Health officials also warn against swimming near dead fish, and advise keeping pets away from dead fish and sea foam, which can contain high concentrations of algae. Pets are not allowed on Anna Maria Island’s beaches, but are allowed on the Palma Sola Causeway on Manatee Avenue leading to the Island.
If the plume of wastewater from the Piney Point discharge reaches the red tide in Sarasota, “… it’s like adding gasoline to a fire,” Sarasota Bay Estuary Program Executive Director Dave Tomasko said.
Blue-green algae was detected in 17 water samples taken in Tampa Bay (indicated by blue dots) from April 8-21 in response to the recent release of polluted water from Piney Point, according to the DEP’s latest blue-green algae report.
Analysis has revealed trace levels of cyanotoxins, neurotoxins that are produced by blue-green algae.
Exposure to cyanotoxins can cause hay fever-like symptoms, skin rashes, respiratory and gastrointestinal distress, and, if consumed, liver and kidney damage, according to the U.S. Environmental Protection Agency.
The closest sample to Anna Maria Island was taken northwest of Robinson Preserve in Palmetto. Bloom conditions continue to be monitored.
– Joe Hendricks contributed to this report
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