Thursday, 27 June 2013

Radioactivity – Everybody cover your junk

I’ll bet you didn’t know that bananas are radioactive. It is one of those weird facts that science abounds with, but it is most certainly true. There is even a tongue-in-cheek unit of radiation exposure that some people (scientists seems too strong a word) refer to as the “Banana Equivalent Dose.”

It’s not anything worth worrying about (trust me, I’ve looked into it), but it’s interesting all the same. The best comparison that I came across while researching this article was made by Keith Yost, a columnist for MIT’s newspaper:

The risk of death is on par with smoking 1/700th of a cigarette, or spending a third of a second in a canoe.”

But what is radioactivity, anyway? The short answer is that it is energy released by atoms as they turn from one substance into another. One of the cooler things about atoms is that some of them  come in different flavours… Unstable flavours. For example, about one in every 10,000 potassium atoms is an “unstable isotope.” What that means is that if a particularly feisty beta-particle comes shooting down from space and crashes into our unstable potassium atom, one of the protons in the nucleus can turn into a neutron.
When you change the number of protons in an atom, you change what that atom is. If you take an atom of mercury and subtract a proton, congratulations you just made some gold. Knock off another proton and it becomes platinum, even better. In our example with the potassium, when a proton turns into a neutron, the atom becomes argon; and when that happens, a little bit of radioactive energy is released.

The trouble with radioactive energy is that large doses of it don’t agree with DNA. When cells divide in the presence of radioactivity, they act like a 17 year old raiding his parents’ liquor cabinet... Things get messy. Mistakes happen when the DNA of cells tries to replicate and that can lead to out of control division down the road, AKA cancer. 

Radiation can also make you sick to your stomach, which is why, if you ever find yourself downwind of a nuclear blast, you don’t want to try catching anything on your tongue as is drifts down from the sky. Unfortunately, Native Pacific Islanders caught downwind from the experimental nuclear blasts on the Bikini Atoll in the 1940's and 50's got this advice a little too late.

Since humans discovered radioactivity in 1895, we haven’t been as careful with it as present common sense would suggest. Marie Curie, a Nobel laureate and co-discoverer of the element radium, died in 1934 from aplastic anemia; probably the result of radium mutating cells in her bone marrow. When the Enola Gay dropped the first atomic bomb on Hiroshima in 1945 it killed between 60,000 and 80,000 people instantly, but the total death toll from the bombing is estimated at around 135,000 when radiation related deaths are included.

And that brings us back to the banana. The reason that bananas are radioactive is because they are loaded with potassium. And, as we now know, 1 in every 10,000 potassium atoms is able to have an identity crisis. Bananas aren’t the only thing that might leave you glowing green if you spend too much time with them, though. Radioactivity is everywhere. Kitty litter, glossy magazine pages, granite counter tops, and even the city of Denver all increase your exposure to radiation. Again though, the doses are tiny, so don’t lose any sleep over it… 

But you might want to invest in some lead-lined underwear.