Health and Medical Professional Issues in Malaysia
Friday, March 16, 2012
NST: LYNAS PLANT: No evidence it's harmful ... By Datuk Dr Looi Hoong Wah
16 March 2012 | last updated at 12:21am
LYNAS PLANT: No evidence it's harmful
By Datuk Dr Looi Hoong Wah, Kuantan, Pahang
IT is painful to see so many well-educated Malaysians, including doctors and professors, being misled by irresponsible people.
Even the president of the Consumers Association of Penang thought that since thorium-40 has a long half-life (24,100 years), it is extremely dangerous when the reverse is true.
Here are some facts with regards to the Lynas controversy:
THE potassium tablets for high blood pressure is highly radioactive, with a radioactivity of 32 Bq/g and we need about 2g to 3g of potassium daily to stay alive. (Bq is the number of atoms decaying in one second.)
The radioactivity comes from potassium-40. This is more than 500 per cent the radioactivity of the Lynas waste which contains only 6 Bq/g mainly from thorium-232.
Potassium when taken stays in the intracellular space where the cancer-sensitive chromosomes are located, whereas the ingested or inhaled thorium-232 remains in the extracellular (outside the cell) space.
All the potassium that we consume daily in our food contains potassium-40 and the normal dietary potassium would give a total of about 80 Bq/g per day.
THE so-called sodium-free salt recommended by health experts to combat high blood pressure is nothing more than highly radioactive potassium salt.
Thorium-232 decay produces only alpha particles, which can be stopped by a piece of thin paper and cannot penetrate even the outer layer of the human skin, whereas potassium-40 in our diet produces dangerous gamma and beta rays from all the three types of beta decay, that is, electron emission, electron capture and positron emission.
A typical 5.5 MeV alpha particle can be expected to travel less than 0.005cm in body fluids.
THE longer the half-life of a substance, the less its radioactivity and as such, the less dangerous it is.
As a simple analogy, if it takes 14 billion years for half of a house to be burnt, there is no chance of anybody getting hurt. But if it takes only 14 minutes for half of the house to be burnt down, many will be injured or killed.
Thorium-232, which is found in the Lynas waste, has an incredibly long half-life of 14 billion years and as such is much less radioactive than the potassium-40 whose half-life is only 1.25 billion years.
IT has been estimated that in the worst-case scenario, the radiation risk from the Lynas plant is only 0.002 mSv/yr.
In Ramsar, Iran, the naturally occurring radiation is extremely high at 260 mSv/yr. This is 13,000,000 per cent higher than the expected worse-case scenario in Kuantan.
And the people in Ramsar have been found to be healthier and live longer than the rest of the Iranians.
There is also no increase in the number of cancer cases.
In the southwestern area of Kerala state in India, the thorium-232 in the soil is as high as 4,000 parts per million as compared with the Lynas waste, which has only 1,650 parts per million.
And studies have shown that the population which has been living all their lives in these areas do not have a higher incidence of cancer and their blood and tissues do not have a significant increase in the level of thorium.
We are exposed to radiation all our lives. In fact, we get 4,400 Bq of radiation from the potassium-40 with a further 3,000 Bq from carbon-14, which forms part of our body tissues.
There is no way we can escape completely from radiation. Even outer space is full of radiation.
Another fear is the inhalation of thorium dust.
We must remember that thorium-232 is heavier than the so-called non-radioactive lead-208 (actually lead-208 does decay, but since it has an even longer half-life of 19 million billion years, the radioactivity is insignificant).
Because of its mass, thorium-232 particles are heavy and it has great difficulty getting airborne.
Normally, these particles get airborne only when they are tiny and the only ones that can get deep into the lungs are those which are about 1 micron in diameter.
These fine particles are only found in the mines and experimental nuclear plants where powerful machines are used or where there is combustion.
The chance of inhaling 1 micron sized thorium particles in the Kuantan air is practically non-existent.
I have not seen or heard or found in the scientific literature of any case of proven lung disease, death or, for that matter, any disease in humans caused by ingestion or inhalation of thorium-232.
Thorium-232, by inhalation or ingestion, has not been proven to have caused a single human death.