Help, It Rained, and I Have Millions of Tritium Atoms in My Hair!

In my last couple of posts, when trying to picture what enormous numbers mean, it was shown that 3 big teaspoons of natural rain falling on my head in Australia would contain about a million tritium atoms. This sounds really scary but as I will gradually show, it is of no concern. Washing our hair would increase the amount.

Tritium forms in our atmosphere every day when cosmic rays hit gases in the air, mostly nitrogen. It is washed down into rivers and streams to the ocean as well as falling directly into the ocean. Tritium forms a minute part of the background radiation that surrounds us always. Life evolved on Earth at a time when background radiation levels were 5, maybe even 10 times higher than today. All life with its complex biochemistry deals with low radiation levels so well, that there was never a need to be able to sense radiation and hence avoid it.

Tritium is even less dangerous than most sources of ionizing radiation. It gently sends out low energy beta rays. Too much of anything can kill us. High dose radiation is dangerous, and we need protection from it.  The bigger the ray particle and/or the energy involved, determines just how harmful various forms of radiation are. Tritium’s beta rays are low energy electrons. It has a half life of about twelve and a half years. The rays are so weak, they cannot penetrate the skin. If swallowed most of it leaves as water in our urine within a day or so. If tritium water vapour is breathed in the World Health Organisation standard for drinking water is 10,00, it leaves again within minutes.

This is an ironic look at statements made out to be scientific fact. Most of the fear about radiation is not true and certainly not scientific fact.

I am still scared! A million sounds such a lot!

If you read my earlier posts on tritium, you may recall that 1 TU (Tritium Unit) is one tritium atom in 10¹⁸ hydrogen atoms. This is far smaller than one person among all the people on earth. You need to visualize one person only on as many planets as there are people on earth all with similar populations as Earth. Three big teaspoons of water contain 12*10²³ hydrogen atoms. One million in 12*10²³ is equivalent to 1 in 10¹⁸. It is mind boggling small.

Australia receives between 2 and 3 TU in rain falling on our land. 1TU is equivalent to 0.118 Bq /L of water.  One becquerel (Bq)is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. The World Health Organization standard for drinking water is 10,000 Bq/L. To reach the same levels of radioactivity in 3 big teaspoons of our rainwater you would need to drink about a quarter of a million litres of water in one day.  Whoops! A small fraction of that amount of water as just H₂O would kill you.

The human body has 30 to 700*10¹² cells. Another enormous number.

So single strand DNA breaks occur naturally in the whole human body over 10¹⁶ times a day. This is another enormous number. Our bodies repair this damage.

These slides have been taken from a talk I gave to a group of CSIRO alumni.

The message is that the radioactivity associated with the Fukushima discharge will not harm anything physically. Fear may cause damage to many livelihoods.