It sounds bad: radioactive isotopes leaking into Biscayne Bay from the nation's sixth largest power plant just 2500 feet from its mangrove- fringed shores.
"Is it safe or advisable to eat fish anymore from Biscayne Bay?" reader Tom Moran asked in an email. "Should we avoid swimming in Biscayne Bay?"
Yes to the first. No to the second. That's the good news. The bad news is recent reports that found elevated levels of tritium in Biscayne Bay, while not posing a human health hazard, reveal Florida Power & Light’s cooling system at Turkey Point is leaking underground and could be threatening marine life to the east and tainting underground drinking water to the west. Still, its presence, even in small amounts is a signal for regulators to be on alert.
Here are 11 things to know about tritium in Biscayne Bay:
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1) There is nothing to panic about. What’s happening in Biscayne Bay is nothing like the disaster in Fukushima , Japan, where highly radioactive water from damaged reactors and storage pools for fuel rods spilled into ocean waters. At Turkey Point, the tritium is simply a “tracer” element that marks water flowing out from under the nuclear power plant’s vast cooling canals.
Federal guidelines set what sounds like a high threshold for drinking water: 20,000 picocuries. But a picocurrie is miniscule. Still, in Biscayne Bay Miami-Dade County regulators say any water above 20 picocuries could signal an unnatural problem.
In January, they found way more: between 2,652 and 4,317 in deep water nearest the canals and lower rates extending about two miles east. That, they said, means cooling canal water, where tritium has been measured at between 1,200 and 16,500 picocuries, has leaked. It’s not the tritium they are worried about as much as other stuff in cooling canal water: high salinity, phosphorus and ammonia, which could trigger toxic algae blooms, kill fish and, if left unchecked, contaminate drinking water supplies.
2) Tritium is all around us. It’s used to make watches, exit signs, dials and non-electronic gadgets glow. It’s also produced when the sun’s rays enter the upper atmosphere, binding with hydrogen and mostly transported through water.
3) From 1945 until the mid 1970s, nuclear weapons testing widely dispersed tritium around the planet. But because tritium has a relatively short half-life of just 12.3 years, most of that has decayed. That leaves nuclear reactors as one of the planet’s major sources of tritium.
4) In a pressurized reactor like FPL uses at Turkey Point, tritium is produced when its neutrons interact with boron and lithium in cooling water, added to control the rate of nuclear reactions and reduce corrosion. While the water is generally very clean, bits of tritium-containing debris can stick to the sides of pipes, “concentrated like scales on a coffee pot,” said David Lochbaum, director of the Nuclear Safety Project for the Union of Concerned Scientists. When the pipes get cleaned, tritium can get released, discharges that the NRC closely tracks.
5) Production of tritium varies, but a state of California hazard assessment calculated the amount of tritium produced by pressurized reactors at about 800 curies per billion watts of electricity. Turkey Point’s reactors produce nearly 1,400 mega watts or 1.4 billion watts.
6) Tritium increases the risk of cancer, California health officials say. But they also say because tritium exits the body rapidly, it should be considered “one of the least-dangerous radionuclides.”
7) The Nuclear Regulatory Commission, which tracks the release of tritium near nuclear power plants, also says the kind of radiation emitted by tritium "does not travel very far in air and cannot penetrate the skin." That means drinking water tainted with tritium is about the only way to get exposed.
8) But there is some debate about what should be considered safe levels. In 2006, California, which is generally more restrictive than the rest of the country on environmental matters, set an ambitious goal to shave the limit in drinking water to just 400 picocuries.
9 ) A 2016 article in the journal Environmental Health Perspectives also argued that too many gaps exist in what’s known about radionuclides. Studies done since 2000 suggest toxicity “may be farther-reaching and more significant than thought at the time the EPA drinking water standards were established,” the report said. More research also needs to be done on the whether naturally occurring and manmade radioactive elements have different health risks, the report said.
10) After FPL uprated the Turkey Point reactors to produce more power in 2013, cooling canals began running hotter. Salinity spiked and high temperatures nearly forced the plant to shut down the reactors. To freshen the canals, FPL began adding massive amounts of fresh water from a nearby canal. But that additional water now appears to have helped spread an underground saltwater plume being tracked by the county and tied to the canals.
11) Is the bay radioactive? No. But is there a chance cooling canal water loaded with salt and ammonia could have consequences? Environmental regulators says yes. That portion of the bay, said Lee Hefty, director of the county Division of Environmental Resources Management, is nearly free of nutrients, meaning its gin clear waters are near perfect for growing seagrass that act as the ocean’s nurseries. Adding ammonia to the mix can be lethal. “We haven’t observed any dead fish or anything. But it represents something that’s not acceptable,” he said. “It needs to be addressed.”
Follow Jenny Staletovich on Twitter @jenstaletovich