Radiation Hormesis challenge to Linear No Threshold theory
I've been following with some interest a discussion which started on Google+ and has spread to PRI's The World and The Economist, of the radiation levels caused by bad engineering and profits-over-people thinking in Japan. The good news is, the radiation levels and types of radiation found outside the plant gate are almost all less dangerous than the natural radiation people face every day in multiple locations on Planet Earth.
There are places (such as Ramsar, Iran http://www.ecolo.org/documents/documents_in_english/ramsar-natural-radioactivity/ramsar.html http://www.iaea.org/Publications/Magazines/Bulletin/Bull332/33205143638.pdf ; Kerala, India http://www.ncbi.nlm.nih.gov/pubmed/19066487, and Brazilian beaches of monazite sand http://www.physics.isu.edu/radinf/natural.htm http://www.jstor.org/pss/3574425) where people naturally are exposed to many times the 'safe' radiation limit, often from radium (which is a nasty, nasty bone-seeking element, far worse than the cesium or iodine found in fallout). They live, they thrive, and that has led science to consider alternatives to the unproven LNT (linear-no-threshold) risk theory.
There is a large amount of data from Chernobyl where the 250,000 deaths predicted by LNT failed to happen, to the Cohen study showing a negative correlation with radon to the Taiwan apartments which saw a 97% reduction in cancers to the undisputable fact that natural background radiation is & always has been far higher in some parts of the world (eg Kerala, India where it is 17 times the safe limit) with no observed ill effects. See http://www.radpro.com/641luckey.pdf and http://a-place-to-stand.blogspot.com/2010/03/low-level-radiation-evidence-that-it-is.html for these and other contradictions to LNT.
The Académie des Sciences — Académie nationale de Médecine (French Academy of Sciences — National Academy of Medicine) stated in their 2005 report concerning the effects of low-level radiation ( Dose-effect relationships and estimation of the carcinogenic effects of low doses of ionizing radiation that many laboratory studies have observed radiation hormesis. While most major studies have used LNT, the French study concerning the effects of low-level radiation rejected LNT as a scientific model of carcinogenic risk associated for doses less than 100 mSv. They consider there to be several dose-effect relationships rather than only one, and that these relationships have many variables such as target tissue, radiation dose, dose rate and individual sensitivity factors. They propose that more study is done on low doses (less than 100mSv) and very low doses (less than 10 mSv) as well as the impact of tissue type and age. Low to moderate levels of radiation poses no risk to human health below a threshold comparable to natural radiation. The Academy also points out that approximately 40% of laboratory studies on cell cultures and animals report some sort of radiobiological hormesis. They state:
“…its existence in the laboratory is beyond question and its mechanism of action appears well understood.”
Yes, it seems contrary to establishment doctrine. But, science, if to be all useful, must accept *fact* and integrate it into thought. A scientific mind, like a parachute, only works when open.