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.
