What a field day for the heat
A thousand people in the street
Singing songs and carrying signs
Mostly saying, "hooray for our side"

Thursday, January 22, 2015

What we talk about when we discuss

Radiation exposure risks. I've been thinking about this post since Confusion where I explained this concept to the shocked and horrified expressions of those listening.

So, it turns out that radiation from Fukushima has reached the Western shorn of America. We'll note here that it wasn't the first radioactive particles from Fukushima to reach the US, nor the only way the lingering radiation from that accident is affecting us.

But, yes the amount of radiation is relatively small at 1 Becquerel per cubic meter of water. The government has declared it "safe", and we all get more radiation every year from just breathing the air than we'd get by an hour in the water.

Sounds wonderful, doesn't it?

Well, here's what we're actually talking about. Some of you are going to die of cancer caused by environmental exposure to radiation. That's just the truth of it. So many people out of one million will contract and die of cancer that can be traced to once source. That's just the facts of life. You're exposed to approximately 300 milli-RADs of radiation every year by just living on this planet (well, in the USA in particular). It takes at least 300 RADs for a lethal dose, so that yearly exposure is 1/1000th of a lethal dose. Pretty small. But then, a 300 RAD has a high chance of killing you within a month or two (and can be averted by a bone marrow transfusion in many cases). And that does needs to delivered to your whole body within a short space of time. And we're talking about living 60-80 some years on Earth.

There is no safe dose of ionizing radiation. The way we think about these things, there are various thresholds for certain effects, like cataracts, having your hair fall out, or reddening of the skin. However, there is no safe level of dose to avoid all effects of radiation. Every dose you receive is a ticket to the Cancer Lottery. And just like a real lottery, more than likely you won't win. The odds, however, are more in your favor when it comes to cancer.

So, how can they say that any radiation is safe? Well, they can't. This is what they mean. These aren't the real figures, because I'm just to mind fried to look them up, sorry. But let's say the actual statistic is 100 out of 1,000,000 of us will get cancer that can be tied to radiation. This exposure may mean 101 people in 1,000,000 will now get cancer. That is a minuscule risk increase (here we are playing with statistics, for pharmaceutical research if a drug takes the instance of a disease from 2 in 1,000 to 1,000 that's a 50% decrease of your chance of getting the disease if you use the drug - never mind the 998 other people who didn't get it either). Basically, it'll hide in the normal variance around the mean or average. So, your chances of getting cancer from this increased exposure is practically 0%. So it's safe. See how that works?

But they're lying to you, Becquerels don't mean diddly squat. Becquerels (and Curies) describe radiation in the air. It's a basic way of saying "we see these many air molecules being effected over this period of time." Sounds important, doesn't it. It doesn't mean squat to you. Because there is another measurement, related to Becquerels that's a little more important, and those are RADs (or Greys). This is the exposure that actually hits your skin. RAD is "radiation absorbed dose." That sounds a little more important, doesn't it. You see where this is going, don't you.

The most important number (without getting even more pedantic) is REMs (or Sieverts). REM is "radiation equivalent man." This is the number that looks at the RAD and applies some multipliers that are quite important, such as the type of radiation you received. X-ray and Gamma (high energy photons) rays are a multiplier of 1, Beta radiation (high energy electrons) are a multiplier of 2 (because electrons are larger, they cause more damage and are more likely to cause damage), and Alpha radiation (basically Helium nuclei stripped of their electrons) is a multiplier of 20. The good thing here is paper can stop Alpha particles, Beta particles don't penetrate very far, but X-ray and Gamma will go all the way through you.

So, when someone tells you any radiation count that isn't given in REM or Sieverts, they're lying to you. These are the two most important measurements (yes, DAP and the others work better, but do you really want a physics course?).

Well, I was going to go on more, but I just received some news I need to process. I didn't want to hold this up. That's most of what I wanted to say.

1 comment:

Dr. Phil (Physics) said...

Beyond Physics, most Americans need a desperate course of study in statistics -- which politicians and advertisers take shameless advantage of.

Dr. Phil