Sciencemadness Discussion Board - Generational radiation exposure

Generational radiation exposure

hyfalcon - 16-10-2014 at 01:11

I've been trying to get some hard information on the effects of radiation exposure in the succeeding generations.

http://www.atomicvetkin.com/genetics.html

The above reference is 15 years old. Is there more recent research? My interest is because of my fathers lifetime exposure.
It was conservatively estimated that he had a lifetime exposure of 19 rem. I'm trying to see if this could have effected my own health due to the fact that he received that exposure prior to my conception. I'm of course worried about any effects that might have been passed on to me. Is anyone currently working on anything regarding this?

Not sure if I chose the right forum for this or not. Toss up between this section and radio-chemistry.

Just to give you a little background on my father's exposures. He was part of the occupation force that hove to in Nagasaki Japan. 6 weeks after the blast, him and some of the crew from his ship, were taken to the epocenter of that blast and were allowed to pick through the trash for souvenirs. His second exposure was working at a gaseous diffusion plant for 2 years. He went from there to a pile reactor in the Idaho dessert that was working on the first nuclear powered plane. While in Idaho, they were air testing A bombs in the Nevada desert. Fallout from those tests blew over his job site and was so bad that they were setting off radiation detectors going INTO the facility. To the point that they just had to turn them off. All of this happened before he came back east where he met my mother and I came about. Maybe I'm tilting at windmills, but I do have a concern as to whether I might have been affected in some way by his lifetime exposure. Any insight into this that anyone has would be greatly appreciated.

[Edited on 16-10-2014 by hyfalcon]

[Edited on 16-10-2014 by hyfalcon]

Chemosynthesis - 16-10-2014 at 08:04

Epidemiologically, it seems highly unlikely: http://www.radiationanswers.org/radiation-and-me/radiation-r...

I had a similar progenitorial exposure from the same project, different circumstances. I do not believe there is any way to know for certain in such circumstances, but the chances of the exposure not only being heritable rather than somatic, and then passing down through the genes seems slim both through available data and my reasoning.

First, consider how sperm is selected; the fastest and most penetrant of the ovum makes a zygote. The likelihood of deleteriously affected sperm being the selected for fertilization seems low given what I have seen in clonogencity assays. Even assuming this is the case, you now have assume that you inherit these traits, which is less likely if the mother's presumably healthy alleles mask a recessive mutation.

hyfalcon - 16-10-2014 at 08:25

Makes sense, thanks for the link. If I'm reading it correctly, if I were to have anything to manifest, it would have done so long before now. I am an only child though, so I don't have any siblings to compare notes with.

[Edited on 16-10-2014 by hyfalcon]

careysub - 16-10-2014 at 12:41

The first thing you should know is that there has been no detectable difference in the offspring of Hibakusha (atomic bomb survivors) compared to other Japanese.

This means that the risk to thousands of highly exposed Japanese is low enough that it cannot be measured through epidemiology.

From "Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII – Phase 2" p. 252:
"The risk estimates provided in Chapter 4 are about 3000
to 4700 cases of excess genetic disease per million first-generation
progeny per gray of radiation to the parental generation.
Compared to the natural (i.e., baseline) risk of genetic
diseases of 738,000 per million live births in the population,"

Let me parse this for you.

For a natural unexposed population the prevalence of a detectable genetic disease is a rate of 0.738 (if evenly distributed 3/4 of the population would have them, genetic disease overall is more common that not). Notice that the extreme prevalence of "genetic disease" as a whole indicates that in general the consequences are quite mild, to the point of being unnoticeable.

This may seem remarkable, but remember humans are a "wild" population that has never been bred to create genetic uniformity and only extremely disadvantageous mutations get culled out. Mutation is study-able in white mice because each strain line is a clone - no genetic variation at all.

A Gray is essentially 100 REM, so an exposure of 100 REM to a parent creates an additional risk of at most 0.0047, and for 19 REM it is an additional risk of this nature that is between 0.0006 and 0.0009.

It would take an enormous high level radiation exposure event (affecting millions of people) to create any change in human heritable mutations that we could detect - if we could even then.

neptunium - 16-10-2014 at 17:24

note that a dose of 100 rem IF absorbed at 1 time is a lethal dose (or closed to ) and is an extreme case scenario ..
If your father received an estimated 19 in two differente exposure ( separated i assume by many months or years) i dont think as his son you should have to much to worry about...but i do understand your concerns

careysub - 16-10-2014 at 17:53

Quote: Originally posted by neptunium

note that a dose of 100 rem IF absorbed at 1 time is a lethal dose (or closed to ) and is an extreme case scenario ..
If your father received an estimated 19 in two differente exposure ( separated i assume by many months or years) i dont think as his son you should have to much to worry about...but i do understand your concerns

100 rem, all at once, is a 100% survival exposure, it is on the boundary for having any clinical symptoms (some will, some want).

A 19 rem exposure in Japan, post bombing, would be accumulated over weeks. Not even blood work would show any abnormalities from the acute exposure.

[Edited on 17-10-2014 by careysub]

Ozone - 16-10-2014 at 19:35

Actually, a Gray is 100 RAD, a Sievert is 100 REM. The difference is the actual dose vs dose equivalent. This involves the knowledge of how much radiation, it's type (for quality factor) and energy. The RAD is the absorbed dose, say 0.01J/kg. The REM is the dose equivalent, which is adjusted for quality factor (e.g. what damage did that energy likely do? This depends on how ionizing the radiation type is). For example, alphas, if ingested, are very bad, a quality factor multiplier of about 4 (non-internal, who cares). Gammas have a low cross section for interaction with low Z materials, e.g. you, and would require a much larger flux for equivalent dose (although the lower the energy, the more likely it is to interact with you), so the factor is one (but, indirect exposure is almost certain). Neutrons can activate you, so about 3, and so on.

It gets quite complicated when considering biological compartments in dose models, e.g. bone seekers and the like (Sr-90, Ra-226/228, Pu, and friends), urinary/fecal elimination (biological half-life), etc. This is especially true with fallout, which contains (depending on half-life) the whole packing-fraction curve (many isotopes and radiation types). Depending on how long the area was allowed to cool off, it ranges from the whole gamut to mostly Sr-90 (beta), Cs-137/Ba-137m (gamma), I-131 (gamma), residual transuranics (mostly alpha, and minimal) and a few others.

Given my druthers, I'd choose to live and not worry overmuch.

Cheers,

O3

careysub - 16-10-2014 at 19:52

Quote: Originally posted by Ozone

Actually, a Gray is 100 RAD, a Sievert is 100 REM. The difference is the actual dose vs dose equivalent. This involves the knowledge of how much radiation, it's type (for quality factor) and energy. The RAD is the absorbed dose, say 0.01J/kg.

You are correct, but all of his measured exposure would have been gamma rays with QF=1, so 100 rad gamma = 100 rem.

neptunium - 17-10-2014 at 07:05

Quote: Originally posted by careysub

Quote: Originally posted by neptunium

100 rem, all at once, is a 100% survival exposure, it is on the boundary between having any clinical symptoms (some will, some want).

A 19 rem exposure in Japan, post bombing, would be accumulated over weeks. Not even blood work would show any abnormalities from the acute exposure.
A 19

yeah i meant 1000...although i wouldnt like getting 100 either..

hyfalcon - 17-10-2014 at 07:36

I thank everyone for the learned comments. It eases my mind. The 7 pollops they found on my colonoscopy this spring in which one was pre-cancerous still has me concerned, but not as much as before. Again, thanks.