Boonlee Ooi: Dear Nick Tsurikov, i believe you on the way to re-measure the lynas rare earth radiation. hope you on the safe way.
1) your photos are show comparison radiation measure in gamma. I guess the rare earth will release alpha, beta radiation as well. Can it be measured?
Nick Tsurikov :
1. Alpha-beta-gamma thing?
Alpha and beta cannot be measured “directly”. The only way is to measure what is in the air and water (in Becquerels per cubic meter of litre), then estimate how much air person breathes per year and how much water person drinks per year. Then there are internationally-accepted coefficients on how to convert “radiation intake” in Becquerels to the actual radiation dose in milliSieverts.
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2) Does alpha, beta radiation harmful to health? alpha, beta, gamma; which is more dangerous to health?
3) There is external and internal human body exposures of radiation from decay activity. I guess internal exposure is more dangerous. am I right?
2 & 3. How harmful all these are?
Effectively, there are different ways how different types of radiation can affect your body; gamma is just a wave, beta is a free electron and alpha – is a particle consisting of two protons and two neutrons that is about 50,000 times heavier than the beta one. Naturally, and quite obviously – a small rock weighting 1 gram will hitting you will have a different effect if this rock weights 50 kilograms…
There are internationally-accepted “radiation weighting factors” and whilst for gamma and beta these are “1”, for alpha it is “20”. So, of course, it is more dangerous, twenty times more dangerous.
The issue, however, is how one gets an “alpha exposure”. The alpha particles are relatively huge and cannot possibly penetrate even a piece of paper or human skin – so the only possible exposure is if one breathes it “in” or drinks it. I did illustrate in my assessment of LAMP, with the help of the main author of the report by the European Committee on Radiation Risk (ECRR - Dr Busby) that the only really dangerous dust particles that can actually go “all the way into the lungs” are less than 1 micrometer in size. The dust of this type is never present in mining and mineral processing, the lowest would be about 5 micrometers, which means that even if there is any dust around – it cannot get into the lungs much. Just ask any occupational hygienist or a doctor. I am not sure, but I would be surprised if some ‘dust particle size characterisation’ measurements will not be undertaken at LAMP, I think they would be…
Water is a different story of course, but if even some stuff will get into solution – no one is going to drink water from some processing pipe inside the plant and, in my recollection, the limits that are put on the discharge water are about the same as the limits recommended by the World Health Organisation for the drinking(!) water.
So – whilst of course monitoring needs to be done and theoretical assumptions need to be confirmed – I do not see any problem with “internal exposures” associated with LAMP…
Boonlee Ooi 1,2,3) Thanks for giving explantion of dangerous level of alpha, beta and gamma. All three radiation are harm to health. alpha will 20 times more dangerous than beta and gamma, but it only travel short distance.
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4) The Thorium is not only radioactive decay, it will decay into Pb, Lead, heavy metal which is proven harm to human brain system. It is also bio-accumulate. May I know does lynas rare earth contents Pb? what is Pb concentration?
Nick Tsurikov :
4. You are absolutely correct – the ‘end product’ of all decays (both thorium and uranium) is lead. And, in my personal opinion, that what may have caused elevated levels of this stuff in blood of children as measured by Dr Jayabalan at Bukit Merah. Please keep in mind though that there the initial concentrations of thorium/uranium/radium (that all decay into lead) were over a hundred times more than they could possibly be at Lynas. Like… For example, some ceramic tiles – which are in many homes and kitchens – may contain (in the glaze) as much thorium as Lynas concentrate and much more uranium, we do not worry much about getting lead from there, are we…?
In addition we do know that thorium decays very slowly – therefore, the “rate of lead generation” will be as slow as the rate of thorium decay; basically something that you need several life-spans just to do a first approximation by measuring anything…
As to what actually is in the Lynas concentrate – I am not sure but I think the ‘Material Safety Data Sheet’ (MSDS) for it should be somewhere in the “public domain”. I think I’ve got it somewhere here, but honestly, do not have the time to look for it in my archives. What I remember is that the ‘heavy metals’ as a group (lead, mercury, cadmium, whatever…) either were measured to be “below detection limits” or somewhere around some tens of ‘parts per million’. You would have to either trawl through Lynas docs or ask them for it – I am not a specialist in lead, its toxicity etc; all I can do is to roughly stimate the rate of its generation…
Boonlee Ooi 4) You also think that lead level in chidren blood was caused from thorium decay.
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5) the media said smoke a pack of cigarette (but it did not said number of stick), cause radiation of 150 milliSv/year. It is CONFUSING to public people. I guess cigarette is thermal radiation, rare earth is alpha, beta, gamma radiation, I dont think cigarette will release gamma, both radiation should be different. can you clarify?
Nick Tsurikov :
5. Radiation and smoking
I did write it somewhere, but cannot find it now…
Basically, what happens:
Tobacco plants (and leaves in particular) have “natural affinity” to polonium that exists naturally, who knows why. This comes from natural radon – like, it is known that in Malaysia on average natural radon concentration is 14 Bq/m3, meaning that 14 atoms of polonium-218 are generated in every cubic meter or air around you every second. Plus, there are two more poloniums in the decay chain of uranium – Po-214 and Po-210.
Naturally, the more of radon is around – the more of it will be absorbed by the leaves. And if a farmer decides to use some phosphate fertiliser to improve productivity – it may be naturally about 2 Bq/g (2000 Bq/kg) of uranium, that will eventually result in 2000 atoms of each (!) of three poloniums to be generated every second and be available for the plant to “uptake”.
Then what happens – we dry the leaves up, chop them and put them into cigarettes. So, when one smokes, polonium is just one of those 40-50 ‘toxic’ ingredients of the smoke.
Now – where it becomes dangerous and important is when we will ‘look into’ the particle size (as I’ve mentioned above). Of course, the particles of tobacco smoke are “sub-micron” in size and can get anywhere inside the lungs – thus if someone smokes: the more he/she smokes – the more he/she has radioactive polonium atoms irradiating the lungs from the inside. [Please do tell this to everyone who snokes - they may change their mind or least will start thinking of quitting...]
As in regards to the number: I, honestly, do not think that 150 mSv/year is entirely correct – I have seen the numbers from 10 mSv/year to 30 mSv/year (using different assumptions and different kinds of tobacco), so 150 looks to me a bit too high…
But I do know why the quoted number is so high - because it is said that this is the "dose to the lung"... Which, in all honestly, should not be compared with the 'overall bosy dose'...
Apologies for maybe getting too technical, but I hope that you and most people will get it…
You see, we are all exposed to three different types of radiation (alpha, beta and gamma). And, of course, different types of radiation affect different parts of the body differently.
Let’s see… For example, I walk on some radioactive material that emits mostly alpha radiation, has fallen over and have it now (a) between my shoelaces and inside the shoes, (b) inside shirt pockets and (c) on my hands. I would not even bother about the stuff inside the shoes (unless they became uncomfortable), in the shirt pockets – the same thing, who cares – it will not go through the shirt or my skin. I will, however, wash my hands thoroughly before eating or drinking – so I will not “ingest” anything.
Now let’s assume that the stuff emits mostly gamma – the situation would be a bit reversed, I will still not care much about the shoes (though will clean them before leaving the area), then I will firstly empty the pockets of the shirt, and only then will wash my hands – as my heart and lungs are, of course, more ‘sensitive’ to radiation than my hands…
I did mention the ‘radiation weighting factors’ above – for different types of radiation. But then there are also ‘tissue weighting factors’ – which are all a faction of “1” and can be from 0.01 for the skin to 0.20 for ‘gonads’.
Effectively what the 'dose in milliSeieverts' is - is a combination of different types of radiation affecting different body parts to a different degree; I would call it a "common denominator" or something... Basically, so we can sompare the dose of nuclear medicine physician (X-rays) to a dose of oil and gas worker doing borehole logging (beryllium/americium - to see what's under the ground), or a worker in mining and mineral processing (all the 'natural' sources of radiation). All measured in milliSieverts per year.
What I am trying to say – and why I wrote the explanation above – is that the quoted 150 mSv per year is the dose “to the lung”, not to the whole body. To get the actual ‘body dose’ (meaning that we can compare the value with the background, possible doses at Lynas or in any other place) one has to multiply the ‘dose to the lungs’ by the ‘tissue weighting factor for lungs’, which, if I remember it right, is 0.12. Therefore, the dose to a person (not lungs) is actually 18 mSv/year – this value actually makes more sense to me and it is within the range of values I've seen before...
Boonlee Ooi @Nick Tsurikov
5) You also agreed the smoke will not give too high value of radiation. Our Govt without study then publish some wrong information to misleading public .
------------>To be continue
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