Tuesday, April 19, 2011

Is Low-Dose Ionizing Radiation from Fukushima a Risk to Health?

The answer is yes but the unknown is how much of a risk because there are so many variables ranging from exposure level, exposure type, internal versus external, and health and age of the person exposed.

I am going to post some research findings on this subject:

THE OLD MODEL OF RADIATION EFFECTS HELD THAT EFFECTS INCREASED IN A LINEAR MANNER WITH DOSE. THE NEW MODEL CHALLENGES THAT LINEAR EFFECTS FRAMEWORK:

MAJIA'S SUMMARY:
Old model assumed only cells directly subject to radiation were damaged.

New model emphasizes how low-dose radiation can cause indirect damage to cells through the bystander effect and through genomic instability.

The effects of low-dose ionizing radiation are variable and can reduce DNA repair mechanisms, operate lethally on cells or some instances activate them depending upon type of radiation, chemical environment, etc.

“In recent years, several lines of evidence have been accumulating that low-dose effects of ionizing radiation involve formerly unexpected cellular phenomena such as non-targeted and delayed radiation effects. These effects clearly contradict the classical paradigm of radiation biology saying that all radiation effects on cells, tissues and organisms are due to the direct action of radiation on DNA…. As another low-dose non-linear radiation response can be added the phenomenon of low-dose radiation hypersensitivity (LDRH) [68] and [69] that has been observed in many cell types. It manifests itself by high lethality”

Dietrich Averbeck, a, Towards a New Paradigm for Evaluating the Effects of Exposure to Ionizing Radiation Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis Volume 687, Issues 1-2, 1 May 2010 pages 7-12


LOW-DOSE RADIATION CAN SUPPRESS BODIES' ABILITY TO FIX DNA DAMAGE
Low-Dose radiation suppresses the body’s adaptive response against genomic instability

Huang L, Kim PM, Nickoloff JA, Morgan WF. 2007. Targeted and nontargeted effects of low-dose ionizing radiation on delayed genomic instability in human cells. Cancer Research 67:1099–1104.

“The demonstration of a bystander effect in 3D human tissues and, more recently, in whole organisms have clear implication of the potential relevance of the non-targeted response to human health. The observations that the progeny of non-targeted cells show an increase in genomic instability as evidenced by an increase in delayed mutations and chromosomal aberrations many generations afterwards indicate the need for a comprehensive assessment of the bystander issue, particularly among genetically susceptible populations….” (http://www.radiation-bystander.columbia.edu/)


KIDS ARE AT INCREASED RISK FROM LOW-DOSE IONIZING RADIATION, ESPECIALLY WHEN THEY ARE ALSO EXPOSED TO CHEMICAL CONTAMINANTS

“Overall, the evidence from the studies conducted following the Chernobyl accident, nuclear tests, environmental radiation pollution and indoor accidental contamination reveals consistently increased chromosome aberration and micronuclei frequency in exposed than in referent children…. Future research in this area should be focused on studies providing information on: (a) effects on children caused by low doses of radiation; (b) effects on children from combined exposure to low doses of radiation and chemical agents from food, water and air; and (c) specific effects from exposure during early childhood (radioisotopes from water, radon in homes). Special consideration should also be given to a possible impact of a radiochemical environment to the development of an adaptive response for genomic damage”

Fucic, A.; Brunborg, G.; Lasan, R.; Jezek, D.; Knudsen, L.E.; Merlo, D.F..Genomic damage in children accidentally exposed to ionizing radiation: A review of the literature. By: Mutation Research/Reviews in Mutation Research, Jan2008, Vol. 658 Issue 1/2, p111-123, 13p;

EVEN SO-CALLED "NORMAL" LEVELS OF "BACKGROUND RADIATION" CAN CAUSE CANCER IN KIDS

“In a recent paper (Wakeford et al 2009 Leukaemia 23 770–6) we stimated the proportion of childhood leukaemia incidence in Great Britain attributable to natural background radiation to be about 20%. In this paper we employ the two sets of published leukaemia risk models used previously, but use recently published revised estimates of natural background radiation doses received by the red bone marrow of British children to update the previous results. Using the newer dosimetry we calculate that the best estimate of the proportion of cases of childhood leukaemia in Great Britain predicted to be attributable to this source of exposure is 15–20%...”

Mark P Little1,4, Richard Wakeford2 and Gerald M KendallUpdated estimates of the proportion of childhood leukaemia incidence in Great Britain that may be caused by natural background ionising radiation Journal of Radiological Protection Volume 29 Number 4 467 10.1088/0952-4746/29/4/001

IMPLICATIONS

It is simply untrue that there are no health risks from Fukushima radiation.

However, it is almost impossible to model those health effects directly because of the complexity of the situation and the variation in individual susceptibility based on their level of exposure, their general health, the other chemicals they are exposed to, and their age, among other factors.

PRACTICAL IMPLICATIONS

Pay attention to radiation results of food testing since internal emitters pose the greatest risk.

Increase overall health by avoiding chemicals that increase susceptibility (known or suspected carcinogenic chemicals) and by eating foods that boost immune response.

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