Drink 58,000 Glasses of Radioactive Japanese Milk = Increase Your Lifetime Risk of Cancer by 4 Percent

NPR has interviewed Peter Caracappa, a health physicist at Renssealaer Polytechnic Institute, about the dangers of the contaminated food found near Japan’s Fukushima Daiichi nuclear plant. Despite the fact that milk and spinach from the are are not being sold because their radiation levels are above Japan’s legal limit, Caracappa believes that the health risk is tiny.

First, some information about radioactive spinach:

Caracappa calculated for me the implications of eating the most radioactive sample of the vegetable reported so far – a bunch of spinach grown in the open air near Hitachi, a Japanese city about 70 miles south of the Fukushima power plant. Japanese authorities reported over the weekend that 2.2 pounds of this particular spinach sample contained 54,000 becquerels of radioactive iodine-131. (A becquerel is a measure of radioactivity.)

That spinach reading is by far the highest reported so far.

It takes a million becquerels to reach a nuclear plant worker’s annual limit of radioactivity – and remember, that’s not enough to do any measurable harm, in the short or long term.

Caracappa figures someone would need to eat 41 pounds of that Hitachi spinach to reach the nuclear power plant worker’s annual exposure limit. “That’s a significant amount of spinach,” he allows.

But what about cancer? That’s probably what most people worry about when they hear about radioactivity in food. Well, it takes 20 million becquerels to yield a Sievert’s worth of exposure; remember, that’s what it takes to increase a lifetime cancer risk by 4 percent.

That translates to 820 pounds of spinach – more than two pounds a day for a year.

And on to the milk:

To reach the radiation dose limit for a power plant worker, you’d need to drink 2,922 eight-ounce glasses of milk. To raise your lifetime cancer risk by 4 percent, you’d have to drain more than 58,000 glasses of milk. That would take you 160 years, if you drank one 8-ounce glass a day.

Even if what he says is true, consumers in Japan will not have to worry about drinking that radioactive milk. The government is restricting the shipment and sale of milk and spinach from those areas, and is conducting tests on other food products as well.

A few more interesting links about radioactivity and human health:

• The Yomiuri Shimbun has an article about how the Japanese government “jumped the gun” with its distribution of iodine pills: “Premature distribution risked ill effects on health, depleted emergency supplies”
• XKCD Radiation Dose Chart – Really helps one understand the comparative seriousness of the different radiation levels one hears about in media reports.
• The 420 Times reassures American potheads that California’s marijuana farms will probably not be contaminated by Japanese radiation.

• Akihabara News – Gadgetry from Japan (Subscribe)
• Dannychoo.com – Your portal to Japan (Subscribe)