The mighty Mississippi, which collects water from America's farming and industrial heartland, is a source of huge amounts of nutrients. Each year those nutrients cause a massive algae bloom just south of Louisiana, creating a "dead zone" the size of New Jersey.

To add insult to injury, on July 31, the state began dumping polluted, nutrient enriched wastewater more than 100 miles offshore from Tampa, adding to nutrient loading from the Mississippi. The wastewater comes from the Piney Point phosphate plant.

The Piney Point story is a sad saga of mismanagement by its owners and by the state Department of Environmental Protection, charged with enforcing state environmental laws to protect the public trust. Built in 1966, Piney Point produced gigantic heaps of radioactive waste, stacks of phosphogypsum that towered 50 to 70 feet over the flat Florida landscape.

Despite numerous warning signs of financial instability, the state continued to allow the plant to operate and accumulate rainwater on those waste stacks. Finally, in January 2001, the owners declared bankruptcy and walked away, leaving state taxpayers to clean up the toxic mess.

Since then, DEP has attempted several approaches to getting rid of Piney Point's toxic wastewater. Unfortunately, Florida has also seen record rainfalls in the same period. As the levels of polluted wastewater rose, so did anxiety about the health of Tampa Bay, the estuary only a mile or two away from Piney Point. One good tropical storm or hurricane could cause a failure of waste lagoons at Piney Point, dumping hundreds of millions of gallons of acidic wastewater directly into the estuaries of Tampa Bay -- a catastrophe that could destroy those resources for decades.

Having spent almost two years not building an incinerator that would actually be a cheaper and more environmentally friendly alternative, the state decided its only option was to use the ocean as the solution to pollution and discharge treated wastewater into the Gulf of Mexico. In January of this year, the state of Florida applied to the U.S. Environmental Protection Agency for an emergency permit to do just that. Dumping began July 31.

The first report from satellite monitoring of the Piney Point wastewater, compiled by University of South Florida scientists last week, finds a plume of chlorophyll-rich water is headed for the Keys but that "there is no solid evidence yet that this is due to the dispersal of treated wastewater," and notes that this is not the first time that Mississippi River water has reached the Keys.

For us in the Keys, the best we can hope is that the nutrient plume headed our way comes from the Mississippi watershed, not from the deliberate actions of our own state environmental stewards. That's not exactly comforting.

The very least DEP should do is start work on an incinerator for Piney Point, right now. If it turns out the Piney Point discharges are, in fact, causing harmful nutrient blooms, they would have a contingency plan. Also, the state is required by its EPA permit to continue efforts to minimize the amount it dumps in the Gulf. And finally, DEP is still going to have to figure out what to do with the estimated 700 million gallons of wastewater which will remain on the site after the EPA permit runs out (the EPA permit only authorizes the dumping of up to 534 million gallons; there are 1.2 billion gallons on site, and every inch of rain adds another 12 million gallons of toxic soup).

DEP should hold meetings in the Keys to explain to Keys fishermen, divers and all those who depend on the reef exactly what they're doing, why they're doing it and how they are minimizing and monitoring for downstream impacts, and to inform the public exactly what steps it is taking to make sure Piney Point is the last of its kind. Our oceans are simply too valuable to use as dumping grounds and solutions to land-based mismanagement.

Until the state comes to tell the people of the Keys what they're doing, we're simply left to gaze at the satellite images and try to guess whether the slug of chlorophyll originated in the heartland -- or how much is coming from our own state.