Three months after the disaster frequently referred to as the worst nuclear event since Chernobyl, Japan's situation remains as critical as the day the 9.0-magnitude earthquake sent some reactors at the Daiichi plant into nuclear meltdown and the others into a state of emergency. Once atoms begin nuclear fission, there is no way to stop the progress of radioactive decay. Unless contained, it will continue to threaten Japan for years.
Unfortunately, the radioactivity has been difficult to contain. As TEPCO threatens to release 40 Olympic pools worth of water, estimated to contain 10,000 times the legal concentrations of radioactivity, into the Pacific, and Japan admits radioactive emissions are more than twice the amounts originallyclaimed, how worried should we be in Teton Valley?
According to government agencies, not at all. Every section of the Environmental Protection Agency's website on the Japanese Nuclear Emergency offers a reassuring guarantee like this one:
"It is important to note that all of the radiation levels detected by RadNet monitors and sampling have been very low, are well below any level of public health concern, and continue to decrease over time."
To some, the repetition of soothing claims sounds like a well-rehearsed song and dance. Alternative news websites, chatroom boards, blogs and local coffee shop conversations are rife with claims that U.S. government agencies are whitewashing catastrophically dangerous levels of radiation.
"The truth," said James T. Powell, "is probably somewhere in between." Powell, executive director of local watchdog organization, Keep Yellowstone Nuclear Free, believes the alarmists' theories about government conspiracies and EPA cover-ups are unfounded. With six Department of Environmental Quality stations in Idaho alone and hundreds of radiation monitors stationed around the country, inspected by thousands of state and federal employees, there is simply no way the numbers could be falsified. And he doesn't think the levels seen so far are particularly dangerous.
But he is troubled that the EPA has taken as few samples as it has. A RadNet surveillance of radiation in precipitation, drinking water, milk and air cartridges, instituted in the wake of the nuclear event, was halted in Idaho due, the EPA website claims, to "a thorough data review showing declining radiation levels in these samples."
The problem with this explanation is that Idaho radiation levels were not declining when RadNet monitoring stopped reporting samples April 14. Boise's first precipitation sample, collected March 22, measured I-131 (a radioactive isotope of iodine) levels at 242 pCi/l (picocuries, or units of radioactivity, per liter). That is about 80 times the legal drinking water limits, the highest levels of rainwater radiation seen in the nation at any time since the Fukushima disaster. Since I-131 has a short half-life, Idaho Department of Environmental Quality said we could expect those levels to decrease quickly.
But, five days later, I-131 had not decreased. Two more samples were taken March 27. The sample recorded on the EPA's more accessible public site showed, in fact, a 60 percent increase, with I-131 measuring in at 390 pCi/l. A second sample, found through an in-depth search of EPA online records, yielded I-131 concentrations of 422 pCi/l. After that, no samples were recorded on the EPA site. And we can't expect an update any time soon - RadNet monitors were shipped out of Boise Tuesday.
This is especially worrisome for Boise residents who get their city water from surface water. Unlike Teton Valley, where water comes from deep in the Snake River Aquifer, Boise city water comes from a surface source, meaning whatever is in the rain is in the water. There is no filtration system in place for radionuclides like I-131.
This is appealing fodder for alarmists looking to "expose" an "EPA cover-up." While Powell doesn't think the EPA has been dishonest, he does think the EPA communication with the public has been unsatisfactory.
"What the EPA is banking on is that, by the time they do routine testing a month out, the high levels will have subsided. What Keep Yellowstone Nuclear free is pushing for is acknowledgement of the high levels now."
Mark Dietrich of IDEQ said that data from air cartridge testing indicates that those levels have, in fact, subsided. Air cartridge data showed a 93 percent decrease in I-131 content from March 24 to April 3. The dates that recorded high levels of radiation in air cartridges correspond more or less to the dates that recorded high levels in precipitation.
"What we really look at is the air cartridge and air filter levels," said Dietrich. "Air samples are taken every day. If you plot out iodine-131 since March 11, they've dropped way off in the last month." Even though we don't have precipitation data, we can conjecture that radiation levels have dropped in rainwater as well, he said.
Dietrich cautioned, "It's easy to take numbers out of context." In regards to the high levels of I-131 found in precipitation, Dietrich said, "Yes, the number is high. But we didn't see any levels high enough to warrant a public health concern."
Dietrich explained, as rainwater dissipates into soil and rivers, the amount showing up in surface-fed water systems is miniscule.
"The drinking water has been largely unaffected. The radioactive content in Idaho is well below the legal limit," Powell agreed.
Even in Boise, where drinking water comes from rainfall and snowmelt, the highest level was reported at .2 pCi/l. A Boise resident who drank a liter of water on March 28 got about as much radiation as if he/she had eaten a handful of Brazil nuts. We receive radiation from all kinds of sources: rocks, sun, food, outer space. The amount of radiation that could have been ingested from drinking Boise's water is small compared to the amount of radiation we absorb every day from natural sources.
Keri Huston, a source water specialist from the nonprofit Idaho Rural Water Association said she doesn't think there's reason to be concerned about irradiated rain, which was measured in far lower concentrations at our nearest RadNet monitor in Idaho Falls. Of far greater concern, she said, are the fertilizers and chemicals in fields, which threaten to taint rural water.
Dietrich said agriculture and livestock won't be affected much either. Though he said cesium, which has a much longer half life than radioiodine, "definitely got deposited in the soil," the quantities are so low that while "you might be able to detect it here and there, you're not going to see enough to make a difference."
But, though the data collected so far might not give reason for alarm, Powell said we shouldn't become complacent.
"You still have exposed fuel and burn-off that's not being contained," said Powell. "These levels we've seen are okay and safe for a short period of time. But if they keep up after a few months, I might begin to worry." KYNF, one of the organizations that pressed the EPA to make RadNet data accessible to the public, would like to see updated sample results on the RadNet site and an improved monitoring network in general.
"I'm not saying it's not a big deal," said Dietrich. "It is. I don't know that there's any radiation level that's good for you - If you can avoid it, avoid it. But we're not seeing levels that warrant changing your habits."