Super bacteria as a result of Fukushima ?

Dear Reader,

I am sure that many of you will be aware of Godzilla the movie monster which was a dinosaur which got a dose of radiation and thus turned into the super monster. Also for those readers who were born in the 1980s there is the infinitely more annoying ‘teenage mutant ninja turtles’ who according to one version were pet turtles which encountered some exotic toxin which turned them into super turtles (more like irksome turtles). Here the toxin turned the turtles into super turtles.

Recently I saw a paper which asked the question of would normal bacteria after a dose of Fukushima radiation turn into super germs which would be immune to antibiotic drugs. The good news is that according to Shigeyuki Nakanishi, John E. Moore, Motoo Matsuda, Colin E. Goldsmith, Wilson A. Coulter and Juluri R. Rao in Ecotoxicology and Environmental Safety, 2012, volume 76, pages 169 to 174 it will not happen.

They found that radiation does not turn germs into super germs, I suspect that while the gamma rays may have increased the mutation rate because the microbes were not being subject to attack by antibiotics at the same time the increase in mutation rate did not make the germs evolve.

I suspect that if germs were never exposed to antibiotics that very few germs would be immune to the drugs, the reason is that the immunity to the drug does not give the germ an advantage if the drug is never present.

Also as many organisms evolve an immunity to a drug or a pesticide by changing their biochemistry to make it more “exotic”, the exotic biochemistry might give the organism a disadvantage when the biocide is absent.

For example penicillin stops germs by stopping them making the proteins needed for their cell membranes, if the germs change to have second new enzyme which the penicillin does not deactivate in addition to their normal enzyme then they will have to make a greater effort to grow as they will have to make two enzymes while normal germs only need to make one.

For example I saw an open university film about biology years ago which explained that normal grass can not tolerate copper, but the grass on a mine spoil head is a special grass which can tolerate copper. As a result the grass on the spoil heap is different to the normal grass in a field which is unable to grow on the spoil head.

Because the copper tolerant grass is less able to grow under normal conditions than the ordinary grass the copper tolerant grass is not able to take over the normal land. In the same way I suspect that radiation on its own will not make the germs evolve into antibiotic resistant germs.

I think that the only way to make the radiation turn the germs into antibiotic resistant germs would be to expose a culture of the germs to both radiation and the antibiotic at the same time.

Depressing film

Dear Reader,

Me and my wife have been watching some disaster films recently, last night we choose to watch “On the Beach” which is a ‘oh so not so joyous film‘ about the end of the human race. The human race is snuffed in the film (and in the novel) out by very intense fallout from a nuclear war.

This made me think about it for a moment, several things were wrong with the physics and the chemistry of the film.

1. The fallout takes many weeks to arrive in Auz, looking at a paper on bomb fallout by some workers from Kyoto, Kanazawa and Hiroshima Universities it is clear that the fallout will be more than 200 times less radioactive gram for gram after ten days than it would have been 2 hours after it was deposited as ‘heavy’ local fallout very close to the bomb detonation.

So by the time that the fallout would have got down under it would have lost much of its strength. In the book on the beach it took much more than ten days for the fallout to arrive in Auz. This means that the reduction in the radioactivity due to simple decay would be even larger.

I had taken a very simple view that no chemical separation would have occurred during the transport of the radioactivity from the bomb detonation to Auz.

2. Around about 10 to 100 days after detonation the majority of the gamma dose will be due to Te-132/I-132, Ba-140 / La-140, Zr-95 / Nb-95, Ru-103 and I-131. While the iodine (I) and tellurium (Te) are very mobile the barium (Ba) and zirconium are less mobile. A good rule of thumb is that the chemical form of an isotope twenty seconds after the detonation will determine how the isotope behaves.

100 % of the zirconium-95 will be in the form of yttrium-95 (half life ten minutes) at twenty seconds after detonation. The yttrium is very non volatile and is likely to be in the form of an solid oxide at that point. I suspect that it will be very likely to become part of the larger particles from things like soil which will fall to earth more quickly. As a result the local fallout close to the bomb will be enriched in zirconium-95 while the distant fallout will have less of this isotope.

The barium-140 will be formed from cesium-140 (half life one minute) which will be the form of this isobar twenty seconds after the detonation. The cesium is only a semi volatile so about 30 % will be in a solid form.

The ruthenium-103 (Ru) is formed by the decay of molybedum-103 (Mo), as the Mo-103 has a half life of seventy seconds it will dictate much of the behaviour of the Ru-103.  The boiling point of MoO3 is about 1160 oC which is lower than that of ZrO2 and Y2O3 (both about 4300 oC) and higher than what I would expect for of Cs2O. So as a result I much of the ruthenium-103 to be lost into solid particles. So the enrichment process may tend to deposit it in the local fallout.

Now according to the graphs published by Japanese workers if all the involatile forms of the radioisotopes are lost from the fallout then the dose absorbed over the ten to one hundred days the will be only three quarters of the dose which would have been suffered if no chemical fractionation had occurred.

Both of these effects would tend to protect the population down under by lowering their dose, I hold the view that a nuclear war would be a horrible event. But I do not think that a total extermination of mankind by fallout would be a certainty.