Dead Dolphins, Radioactive Mountains: Inside Florida’s Phosphorus Crisis

“This is not normal,” Caulin Donaldson insists, the video wavering as he circles the body of a dead dolphin which washed up on Redington Beach in the Tampa Bay area this August. “For anyone who says that this red tide is natural, it’s not. Dolphins don’t wash ashore like this every year.” Donaldson has amassed over 1.4 million followers on TikTok for his beach clean-up videos, sometimes funny and always emphatic. In the past few months, he has focused on the impact of a severe red tide on Tampa Bay. Panning away from the dolphin, he points out thousands more dead fish on the beach. Drone footage shows the shoreline littered with carcasses.

Like wildfires in the west and hurricanes in the east, Florida anticipates the toxic algal blooms known as “red tides” every year now. In past centuries, red tides happened once every few decades, but because of rising sea temperatures and pollution, Florida has suffered red tides every year since 1998. The culprit is Karenia brevis, a microscopic organism which produces a suite of neurotoxic compounds called brevetoxins, killing marine species up and down the food chain. Year after year, Florida’s waters bloom red, and vast quantities of dead fish wash up on beaches. But this year, Tampa Bay has seen the worst red tide in the past fifty years. And its severity is no coincidence.

In late March, leaks were discovered in a phosphogypsum pond at the abandoned Piney Point fertilizer plant near the coastline of lower Tampa Bay. This pond held approximately 480 million gallons of toxic wastewater, a decades-old byproduct of phosphate processing for fertilizer. If the pond’s walls broke, a 20-foot tall wave would have flooded the surrounding neighborhood. Instead, the state authorized 215 million gallons of wastewater to be dumped into Tampa Bay. This toxic wastewater was high in nitrogen and phosphorus, which are key nutrients for Karenia brevis’s growth. By July, over 3,400,000 pounds of dead marine creatures had been collected from beaches in Pinellas County alone.

This is not the first ecological disaster implicating Piney Point. In its 35 years of operation from 1966-2001, a succession of owners illegally and legally dumped hundreds of millions of gallons of wastewater into Bishop Harbor, an estuary flowing into Tampa Bay, causing massive fish kills, toxic plumes of air, evacuations, and groundwater pollution. Under state control after the plant’s closure, 1.1 billion more gallons of wastewater were dumped into Tampa Bay between 2003 and 2007. Coverage by the Tampa Bay Times over the past decades charts a startling history of mismanagement, greed, and negligence on the part of Piney Point’s owners, the county and the state. The Center for Biological Diversity and local conservation groups are currently suing Governor DeSantis and Florida regulators for years of mismanaging Piney Point. In 2003, a top state regulator called Piney Point “one of the biggest environmental threats in Florida history.” Twenty years since the plant’s closure, the threat it poses to ecological and public health has not diminished.

With each leak and heavy rainfall, Piney Point threatens the future of Tampa Bay. Hundreds of millions of gallons of untreated wastewater sit pooled atop Piney Point’s 50-70 foot tall gypstack, which itself is filled with radioactive phosphogypsum, a byproduct of creating phosphoric acid for fertilizer. For every ton of useful phosphoric acid produced, five tons of useless phosphogypsum are created, and heaped into vast mountains of radioactive waste with no clear disposal method. And Piney Point is only one of 25 gypstacks in Florida, which altogether contain two trillion pounds of radioactive phosphogypsum. Many of the other gypstacks, located farther inland, threaten the Floridan Aquifer, which supplies drinking water for 60% of Florida residents, and has been contaminated by gypstack leaks before. Florida is at the epicenter of the phosphate industry, supplying 80% of the US’s phosphate and 25% of the world’s phosphate; Florida’s residents and ecosystems suffer much of the industry’s toxic excesses. To understand why this environmental hazard has been allowed to persist, we should take a closer look at phosphorus.

Phosphorus is essential to organic life. It makes up 1% of our body weight, and is found in our DNA, cells, bones, and teeth. Plants require it for photosynthesis and many other functions. But phosphorus is a highly reactive element, and never found uncombined in nature; many of the compounds it forms are not immediately accessible to plants. Wild plants have developed elaborate mechanisms for finding and securing phosphorus, ranging from tailored chemical secretions to expansive root systems. By far their most common adaptation, though, is acquiring phosphorus through symbiotic relationships with mycorrhizal fungi.

This knowledge is both relatively recent and rarely applied in commercial agriculture, which has a far less nuanced relationship to phosphorus. For one, most modern crops are “dumb”—they were cultivated in artificially fertilized soil, and lack the innate abilities of wild plants to seek out phosphorus. Then when phosphate fertilizer is applied, most of it immediately reacts with soil minerals to form inaccessible compounds, forcing farmers to apply far more fertilizer than crops can use.

Phosphorus build-up in soil causes its own problems to farmers, and as much as 40% of phosphate fertilizer ends up as runoff polluting rivers and lakes and oceans. The damage to freshwater ecosystems in the US from excess nitrogen and phosphorus exceeds $2.2 billion dollars per year. At best, the common application of phosphate fertilizers is inefficient and unsustainable. At worst, it is an ecological and public health crisis from cradle to grave; from mine to radioactive gypstack to field to polluted waterway.

We can’t delay addressing this issue much longer, because phosphorus is a finite resource. Each year it grows more expensive for farmers, and some scientists estimate that current global reserves of phosphorus rock may be depleted in 50–100 years. Meanwhile, phosphorus mining is an ecologically devastating industry with a hulking radioactive footprint, characterized at every stage by waste. If this was, as the fertilizer industry claims, the only way to feed the world, then we should still be seeking at every step to curb the industry’s toxic excesses. But it turns out that phosphate rock mining is not essential.

While phosphate mining is riddled with inefficiencies, nutrient cycling in nature is strikingly efficient. Animals, including humans, excrete almost 100% of the phosphorus they consume. Only half of manure today is cycled back into farmland, but manure provided all the phosphorus that crops needed for centuries, and remains a simple, practical solution to an outlandishly wasteful problem. Here, regenerative agriculture comes into play. Regenerative agriculture prioritizes soil health, including those beneficial mycorrhizal fungi that provide wild plants with the phosphorus they need. Practitioners often reincorporate animals and their manure into farming. Together, utilizing manure and maintaining healthy soil microbes can make farmers far less reliant on inputs like fertilizer.

To soften the transition into a more sustainable agricultural practice, scientists have found so much “legacy phosphorus” in commercial farmers’ soil, the UK could meet its phosphate fertilizer demand for the next 54 years with the phosphorus already in their fields. Other global projections convey similar overabundance. Regenerative agriculture is not only a bright hope for farming in coming decades of climate instability. It circumvents the need for further habitat destruction and radioactive waste from phosphate mining and processing, and provides a way to increase the health of marine ecosystems around the world currently polluted by agricultural runoff and plagued by toxic algal blooms.

From seashores riddled with corpses in Tampa Bay to agricultural runoff polluting rivers a thousand miles away, phosphate fertilizer has exacted a heavy toll on the American landscape. Discarded mountains of radioactive phosphogypsum remain a looming problem. But we know enough now to say—it doesn’t have to be this way anymore.


Image courtesy of Flickr. Originally published by S&S on Sept. 22, 2021.

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