Southwest Florida’s recent toxic algae blooms were unprecedented in scope, persistence and sheer nastiness. Also unprecedented was how Lee County disposed of some of the crud, shown by science to be potentially carcinogenic to humans.

With $1.61 million from the Florida Department of Environmental Protection, the county hired the California-based firm AECOM to mount a “suck it and truck it” operation, vacuuming algae from Lee County canals, loading the slurry into tanker trucks, then hauling it to North Fort Myers for processing. Martin County, which was also slimed, hired the firm for a smaller treatment operation as well.

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The technique is "an absolutely new process," said AECOM's Dan Levy. "There hadn't been the money for it until the governor made his executive order, which freed up the funds." (Rick Scott's state of emergency declaration made $3 million in cleanup money available to hard-hit counties.)

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The algae solids were "dewatered," and the resulting mass was taken to a Lee County landfill in Hendry County, with the stipulation that it be covered to protect wildlife.

The liquids were treated to Florida Department of Environmental Protection standards, said Lee County spokeswoman Betsy Clayton, then transferred into a 5-million-gallon holding pond almost the size of five football fields 50 feet wide and 10 feet deep, before being pumped into a 2,600-foot deep well, below the confined drinking-water aquifer, Clayton said.

Injecting water into this underground geologic region, known as the boulder zone, is not a new notion. Some south Florida municipalities send their treated sewage effluent down there and the South Florida Water Management District has proposed pumping polluted Lake Okeechobee water into the boulder zone during high-water periods to reduce the strain on the Caloosahatchee and St. Lucie estuaries.

But questions remain about this method, which has not proven foolproof.

In 2016, effluent from Miami’s wastewater treatment plants escaped the boulder zone’s confines, showing “that fractures, karst-collapse structures, faults, or other hydrogeologic features may permit effluent injected into the Boulder Zone to be transported to overlying permeable zones in the Floridan aquifer system,” from which much of the state gets its drinking water, according to a U.S. Geologic Services report. And in the early 1990s, 20 south Florida disposal wells failed, sending partly treated sewage into aquifers that may be needed for drinking water in the future, according to a ProPublica report.

“A lot of the toxic things we’re injecting into the boulder zone may not stay there,” said Nicole Johnson, the Conservancy of Southwest Florida’s director of environmental policy. “We really need to be careful as we look at the best way to dispose of this stuff (and) get a better understanding of what happens to it.”

One of Calusa Waterkeeper John Cassani’s concerns is that the algae the county removed produces microcystin, a potent toxin that could not be completely removed from the treated solids and liquids.

The microcystin that remained was injected into the well, albeit in small quantities. In all, 202 grams of microcystin — a little less than half a pound — was sent underground mixed into more than 60 million gallons of water.

Catchiness aside, the old adage: “The solution to pollution is dilution” has not proven sound environmental policy, Cassani said.

"Microcystin is a horrendously potent toxin. It's carcinogenic. The temptation is to say, 'well it's confined, so it's no worse than wastewater or surface water," Cassani said, but that's a mistake. "Even though it's not regulated, it's a known toxin — and it bioaccumulates."

Especially since even diluted, the contaminants remain, Cassani points out, and in quantities above the EPA’s recommended safety threshold for infants and preschool children. Instead, the DEP used a different standard established by the World Health Organization.The DEP did not immediately return a request for comment.

University of Miami professor and algae researcher Larry Brand is less worried about potential danger from the deep well injections ("I know it's something some environmentalists don't like ... but in my view, it's probably OK.") and more concerned about taxpayer financing and the distraction factor of such operations.

"It's incredibly expensive, (but) it gives politicians a chance to say they're doing something," Brand said. "Realistically, given the scale of this, there's no logistically or economically good way of getting rid of these blooms once they've happened. You've got to stop the nutrients at their source."

Cassani agrees.

"If injecting toxins underground becomes a standard response to cyanobacteria blooms, it will bring less emphasis and funding to regulating nutrient pollution — the underlying cause."

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