Science and Technology

Wastewater crisis sheds light on Florida’s environmental troubles

University experts in marine science, environmental health, law, and engineering reflect on state and local leaders’ decisions during a crisis prompted by contaminated water spewing from an old phosphate retention pond.
An aerial view of the Piney Point reservoir site. Photo: Florida Department of Environmental Protection
An aerial view of the Piney Point reservoir site. Photo: Florida Department of Environmental Protection

Government leaders from across the state of Florida are breathing a sigh of relief as the threat of a toxic flood seems to be dissipating in the Tampa Bay area.

Last weekend, more than 300 homes and businesses near the Piney Point site in Manatee County—just south of Tampa—were forced to evacuate when a retention pond holding contaminated water from a former phosphate plant began spewing the liquid from a ripped seam in its containment liner. The leak threatened to topple one of the reservoir’s walls, potentially sending a 20-foot wall of toxic water into the surrounding community, and Tampa Bay just a few miles away.

On Saturday, emergency officials, working with the state’s Department of Environmental Protection and the United States Army Corps of Engineers determined that siphoning water out of the leaking reservoir, into another pond and into Tampa Bay, was the best way to prevent a larger flood.

While their efforts may have stemmed a crisis for nearby residents, the impacts of dumping an estimated 165 million gallons of this water into Tampa Bay could be extremely damaging to the Gulf Coast of Florida and the state’s tourism-dependent economy, University of Miami experts say. The Piney Point emergency also reveals a larger struggle in the Sunshine State—how to hold powerful corporations accountable when they damage the environment.

With work crews funneling the contaminated water into Tampa Bay, officials are now watching closely to see whether the nutrient-rich wastewater will spawn algae blooms that could cause fish kills and other environmental damage.

Larry Brand, a phytoplankton ecologist at the Rosenstiel School of Marine and Atmospheric Science, hasn’t seen the actual numbers on the concentrations of nitrogen and phosphorous in the water being pumped, but he believes the nutrients may generate an algal bloom about a week after they are dumped.

Those effects could have a detrimental impact on marine life. An abundance of algae in the water prevents light from reaching the seabed, killing seagrasses that are important habitats and nurseries for many species.

“We have seen this process many times throughout the world,” Brand said.

Even worse, if the blooms are very dense, they could eliminate all of the oxygen at night, generating an anoxic habitat and producing toxic hydrogen sulfide.

“This would then kill virtually everything in the bottom water and benthos,” he said, noting that such a habitat is often referred to as a “dead zone.”

Biology professor Kathleen Sullivan Sealey, who studies coastal ecology and water quality in Florida and the Caribbean, agreed. An example of a dead zone is at the mouth of the Mississippi River, where many oil spills have prompted the loss of life. 

“We know that putting these chemicals in the water will cause irreparable damage,” Sealey said. “Once these nutrients get in the water, they are hard to get out.”

But while high concentrations of nutrients often lead to algae blooms, scientists still have a difficult time predicting which species of algae will win the competition for those nutrients. One species of concern is the dinoflagellate Karenia brevis, better known as Florida red tide, which produces a powerful neurotoxin that kills fish, dolphins, manatees, sea turtles, and seabirds, and makes people sick.

“The hot spot for this species is along the west coast of Florida from Tampa Bay to Naples,” Brand said. “We have had a moderate red tide since this past November. It started at the mouth of the Caloosahatchee River, and currents have carried it up to just south of Tampa Bay in Sarasota County. Should the currents lead to a mixing of this nutrient-rich water from Piney Point and the red tide, a much larger red tide could develop and lead to a large fish kill.”

Other factors, like the presence of other chemicals that might be introduced with the nutrients, could also play a role in whether a bloom will develop, according to Kim Popendorf, a chemical oceanographer at the Rosenstiel School. 

“Relatively low concentrations of copper, for instance, can prevent algal growth, which comes with its own problems as it reduces the growth of both harmful algal blooms, but also could kill all of the beneficial phytoplankton and bacteria in the water,” she said. 

The decision to pump the Piney Point water into Tampa Bay is doubly unfortunate because of the progress the region has made in the past 30 years, Sealey said. In response to the harmful effects of pollution from industry, the Tampa Bay Estuary Program was founded in 1991 and it remains one of the most important success stories in coastal restoration, she said. The effort has improved the seagrass beds, limited the nutrients present in the water, and allowed many species, like sting rays, to return, Sealey said.

“This is undoing what millions of dollars and what thousands of people have worked to do to clean up Tampa Bay,” she added.

In addition, the question of how to adequately clean up contaminated sites in Florida is not limited to Piney Point, Sealey said. In fact, there are many other sites with reservoirs just like it, she added. State and local officials are now trying to determine how to remediate these sites, which have changed ownership several times, but there is no clear path.

“When many of these phosphate mines closed, they put in these temporary impoundments [to hold the contaminated water],” said Sealey. “They paid millions of dollars to these consulting companies who put in these temporary pools. But they can’t last forever.”

Phosphate mines have a long history in Florida, and trace back to the 1940s and ’50s, Sealey said. Phosphate rock is used to make phosphorous, one of the critical ingredients in fertilizer, and the raw mineral is readily found in the southeastern United States.

Today, the Environmental Protection Agency ranks phosphate mining as the fifth largest mining industry in the U.S., and most of the nation’s phosphate is mined in Florida, North Carolina, and Tennessee. The Sunshine State is home to 27 phosphate mines, and nine are still active, according to the Florida Department of Environmental Protection. Most are clustered in the center of Florida, west of Orlando.

To produce the phosphorous needed for fertilizer, however, the companies had to dig up the phosphate. Justin Stoler, associate professor of geography and regional studies as well as public health, who studies water access and quality, said that after it is mined, phosphate rock is put into an acidic solution of water and other chemicals needed to make fertilizer. The leftover waste is called phosphogypsum.

Without any designated place to contain this waste safely, companies like the one operating at Piney Point simply piled it on the ground in a large circle or rectangle, with a plastic liner underneath. This byproduct hardened to form the “stacks” that are the walls of the reservoirs at Piney Point, and the water left from the waste often pools in the middle and mixes with rainwater to form the reservoirs.

Although heavy-duty liners prevent the water from leaching into the ground, the weight of rainfall and other waste dumped into the pools can stretch the liners, causing them to tear. This is what prompted the water—which could contain radon gas, arsenic, nitrogen, mercury and lead—to start gushing from Piney Point last week, Stoler said.

“Those heavy-duty liners are a common way we contain waste products,” he added, noting that they are similar to the liners used when creating landfills or burying any toxic waste, as well as to cap a landfill. “But it’s not ideal.”

Often a capped landfill can be turned into a park or recreational space. Some former phosphate mines have done this in central Florida, Sealey said. But older ones, like the Piney Point site, have not been held accountable, she added.

Another way to get rid of the contaminated water, which Manatee County leaders are now considering, is to build a deep injection well that reaches hundreds of feet below the ground and to pour the water from Piney Point into it.

“Deep-well injection is effective in that it keeps the wastewater from being discharged into surface water bodies, thereby avoiding very negative ecological impacts and associated water-quality impairments,” said David A. Chin, a professor of environmental engineering at the University of Miami.

Yet a well could also be problematic, Stoler said, because if any of this contaminated material gets into Florida’s two aquifers, it could affect the state’s sources of clean drinking water. Sealey said that in the past, the Keys built similar wells and some of the material ended up seeping into the ocean several dozen miles from the well and damaging coral reefs.

Both Sealey and Stoler agree that the best course of action would be to treat this water before releasing it anywhere, but they acknowledged that it is costly. Yet, rather than the taxpayers, who are funding the emergency actions happening today, the companies that cause this damage should be forced to mitigate the environmental impacts, Sealey stated.

“Why do the people of Florida, or the U.S., have to pay for the mess that a private company made?” Sealey asked.

Abigail Fleming, the Fredman Foundation Practitioner in Residence at the University of Miami School of Law’s Environmental Justice Clinic echoed her sentiments and said the entire crisis points to a larger issue.

“Once again, the state of Florida failed to keep ecosystems and economies safe; and now, taxpayers will suffer the consequences,” Fleming said. “Although I can envision environmental groups and residents bringing a lawsuit to seek relief, litigation is expensive, time-consuming, and may not address systemic issues—one being Florida’s lax enforcement of environmental regulations.”