The Oregonian has a helpful Q&A on radioactive fallout from the Fukushima Daiichi nuclear plant showing up in Northwest milk.
You may have seen the news about very low levels of the radioactive isotope iodine-131 showing up in milk from Spokane (by very low, I mean 5,000 times lower than the level at which government regulators would intervene for safety concerns).
Oh yeah, Earl Fordham of the Washington Health Department told me yesterday. “We expected that to happen.”
Fordham is the department’s director of radiation protection, and he fielded a few questions from the crowd at last night’s state of Hanford meeting in Portland (more on that later).
The radioactive isotope iodine-131 has blown across the Pacific to the West Coast and it has fallen onto grass, hay and water consumed by cows. It’s no surprise that it’s showing up in the milk produced by the cows, Fordham said.
The first detection of low-level radioactivity in the air reaching the West Coast from Japan was made by nuclear weapons testing detectors developed in part by Pacific Northwest National Labs.
Now the the radiation is showing up in secondary places – in the milk that is regularly tested by the Environmental Protection Agency.
Milk naturally contains its own levels of radiation from potassium-40, and it’s also considered a useful indicator of radioactive fallout. It’s also consumed by many children, who have a lower threshold for safe exposure. So pasteurized milk samples are collected at dairy plants regularly and tested for radioactivity.
Fordham said the timing of the Fukushima fallout was actually fortunate for cows and milk-drinkers. Right now, most cows are eating stored feed and not grass where radioactive fallout is more likely to land.
He also said the only Fordham said the only chance of any kind of health threat would come if a person drank the milk at the tested levels continuously for a year. But iodine-131 has a very short half-life of eight days, so it will be gone before it can accumulate to a dangerous level.
More from the O’s Q&A: