State Rep. Erin Grall wants to restrict the use of partially treated sewage sludge in the upper St. Johns River watershed, which includes Blue Cypress Lake and Indian River County.
A bill Grall, a Republican who represents Indian River County and part of St. Lucie County, filed Tuesday morning would prohibit the state Department of Environmental Protection from authorizing disposal of "domestic wastewater biosolids" in the river's upper watershed.
But there's an out: So-called Class B biosolids can be spread on farmland if the landowner can "affirmatively demonstrate" nutrients from the sludge won't run off the land and cause pollution downstream.
Class B biosolids have been treated at sewage-treatment plants but still contain pathogens, heavy metals and high levels of nitrogen and phosphorus, which can feed toxic algae blooms.
The law wouldn't restrict use of highly treated sewage sludge known as Class AA biosolids, even though they still contain high levels of nitrogen and phosphorus.
A state law approved in 2013 prohibits spreading Class B biosolids on farmland in the Lake Okeechobee and St. Lucie River watersheds, which includes St. Lucie and Martin counties.
Data from DEP shows that shifted the practice north, particularly to the St. Johns River watershed.
Grall's bill specifically notes Class B biosolids would be banned at Blue Cypress Lake, the headwaters of the St. Johns River in western Indian River County and home to the world's largest concentration of osprey nests.
A TCPalm investigation published in June questioned whether biosolids spread at Pressley Ranch near Blue Cypress Lake were to blame for rising phosphorus levels, which can — and two weeks later did — cause a highly toxic blue-green algae bloom in the lake.
Testing by the Ocean Research & Conservation Association in Fort Pierce found the bloom in Blue Cypress Lake contained the toxin microcystin at a level of 4,700 parts per billion.
The World Health Organization considers microcystin levels higher than 2,000 parts per billion "very highly hazardous" in recreational contact.
Microcystin can cause nausea and vomiting if ingested, and rash or hay fever symptoms if touched or inhaled. Drinking water with the toxins can cause long-term liver disease.
Grall told TCPalm in June she would support banning Class B biosolids if water-quality data "indicates phosphorus and nitrogen are at unsafe, elevated levels along the St. Johns River basin.
Beyond that, legislators should "consider bans and stricter oversight by (the Florida Department of Environmental Protection) wherever nutrient levels are a problem."
Since then, Indian River County commissioners have enacted two six-month moratoriums on spreading partially treated sewage on fields.
When the panel approved the second moratorium early this month, Commissioner Peter O'Bryan said a permanent ban enacted by the state "is one of our top priorities in the upcoming legislative session."
The ranch owners have agreed not to use biosolids "at least through 2019," County Attorney Dylan Reingold told commissioners.
The Fellsmere City Council also has extended its biosolid moratorium for the next six months.
In July, the Treasure Coast Regional Planning Council called for Florida's state and local governments to reduce and eventually eliminate the land application of biosolids and to start looking for alternative ways to dispose of the sewage sludge.
Action by the council — which represents Martin, St. Lucie, Indian River and Palm Beach counties — is merely a recommendation and not binding.