How long afterwards were Hiroshima and Nagasaki uninhabitable due to radiation?

[Dayman]

I've always heard that the sites of nuclear explosions were to be avoided for a very long time. I understand those two bombs were low yield compared to today's, but still, I would feel weird visiting those places today.

[Sphere]

Actually, in comparison to most modern nuclear weapons, the two used against japan where quite "dirty". Only a very small fraction of the Uranium & Plutonium was actually fissioned (<3% IIRC), the rest was just their to reach critical mass.

[Rhaegar1]

what he said.

anyhow did you know that only about 500 people in hiroshima and nagasaki died as a result of leukemia and solid cancer (stochastic effects) opposed to the + 200.000 dying from the initial blast and radiation disease (deterministic process). I allways think that result is quit low.

of course that's only the people who died from it and not taking into account all those whom quallity of life was significantly decreased without dying.

[Ludicus]

.

anyhow did you know that only about 500 people in hiroshima and nagasaki died as a result of leukemia and solid cancer

Wikipedia...

Not at all.

Detailed answer:
Study, number of subjects: 86,572 survivors.
From this group, 37,458 survivors (43%) with doses less than 0.005 Sv were primarely survivors who were located more than 2.5 km from the hypocenter.

Solid cancer deaths, and noncancer disease deaths by radiation dose:
Deaths,Total
Solid cancer deaths (1950-1997) : 9,335
Noncancer disease deaths (1950-1997) 31,881

[Rhaegar1]

Watch out where you're waving wikipedia around, I have my level 3 radiation hygiene grade so I'm not just a wikipedia wiseguy on this subject
I won't doubt the numbers you give but I think they lack the fact that it's impossible to distinguish cancer due to radiation from 'natural' cancer. The only way of actually getting some data out of it is using statistics and since my source (which is somewhat older than yours I guess) speaks of 7578 deaths of solid cancer in total. I'm pretty sure the average japanese death by cancer hasn't been substracted from your (obviously more recent) number of 9335 deaths.

But I admit I wasn't clear on what I meant in the post you're refering to, I said 500 cancer deaths but what I meant was about 500 deaths above the average of japanese cancer deaths. And it's not a number I got from wikipedia but one I heard mentioned during the level 3 course from one of the trainers.

In my book they are talking about an increase of about 1.4 % per Gray of cancer with deathly result but since most people allready die within few days/weeks after radiated by about 3/4 Gray there's only a small amount of people where the radiation caused a significant increase in death by cancer which was the point I tried to make.

On top of that does my source mention that from the 38100 people from the study group of 86572 that allready died 23% died from cancer which is allthough perhaps a slight increase above normal not an outragous number since cancer is in the netherlands for example the number 1 course of death so probably also somewhere around that percentage (or even higher)

Sorry it has become such a long story but this is my primairy source (besides wikipedia )
Inleiding tot de stralingshygiene (Introduction to radiation hygiene) from A.J.J. Bos and others (2000 version)

Wikipedia...

Not at all.

Detailed answer:
Study, number of subjects: 86,572 survivors.
From this group, 37,458 survivors (43%) with doses less than 0.005 Sv were primarely survivors who were located more than 2.5 km from the hypocenter.

Solid cancer deaths, and noncancer disease deaths by radiation dose:
Deaths,Total
Solid cancer deaths (1950-1997) : 9,335
Noncancer disease deaths (1950-1997) 31,881

[Ludicus]

Watch out where you're waving wikipedia around,

" did you know that only about 500 people in hiroshima and nagasaki died as a result of leukemia and solid cancer"
Sorry, but it´s the wikipedia reference: "Since then, more have died from leukemia (231 observed) and solid cancers (334 observed) attributed to exposure to radiation released by the bombs"

I won't doubt the numbers you give but I think they lack the fact that it's impossible to distinguish cancer due to radiation from 'natural' cancer

Leukemia
Pierce and coleagues estimated that 44% of leukemia deaths among survivors with doses exceeding 0.005 Sv were due to radiation exposure.
They evaluated patterns of risk by sex, age and exposure, and time since exposure for four major subtypes of leukemia (acute lymphocytic, acute myelogenous, chronic mielogenous, and adult T-cell)
Dose-response relationships were seen for the first three but not for the last one The estimated numbers of cases in excess of background were 17.1 for acute lymphocytic, 29.9 for acute myelogenous, and 25.9 for chronic myelogenous. The other major type, chronic lymphocytic, showed no excess - but its infrequent in Japan.
The results of analysis of all types of leukemia showed dependence on sex, age at exposure, and time since exposure, similar to those for for the mortality data, and led to a model that is based on mortality data.
Analysis of leukemia are based on bone marrow dose.

Analysis of the combined category of all solid cancers are based on colon dose.
Analysis of site-specific cancers are based on specific organ doses.
Preston and collegues estimates that 8% of the 5502 solid cancers deaths among those with doses exceeding 0.005 Sv were due to radiation, much lower than the corresponding percentage of 44% for leukemia.

Lymphoma
analysis of mortality data showed no evidence of an association for lymphoma; its not possible to distinguish between Hodgkin and non Hodgkin. From 210 lymphoma cases, a statistically significant dose-response was found for males, but not for females.

Multiple Myeloma
There is a statistically significant dose-response based on mortality data, but incidence data showed little evidence of such an association.

Nervous sytem tumors
A statistically significant dose related association was observed for all nervous sytem tumors.


Significant dose response relationships were observed for all solid nodules, adenoma, nodules without histological diagnosis, autoimmune hipothyroidism,stomach tumors, breast diseases (proliferative and nonproliferative)

Non-neoplastic diseases:
A statiscally significant dose-response relationship with mortality from non-neoplastic diseases in A bomb survivors was demontrated (hearth disease, stroke, live cancer,diseases of digestives, respiratory, and hematopoietic systems)


Life shortening:

A clear decrease in median life expectance with increasing radiation dose was found.
------
Summarizing:
The Life Span study cohort consists of about 120,000 survivors of atomic bombings in Hiroshima and Nagasaki who have been studied by the Radiation Effects Research Foundation. the cohort includes a large proportion of survivors who were within 2.5 kms of the hypocenters ans similar sized sample of survivors who were between 3 and 10 kms from the hypocenters and whose radiation doses were negligible.

The population has a long follow-up (50 years) and includes both sexes and all ages of exposure, allowing a direct comparation of risks by these factors.
Because of the use of Japanese family rgistration system, mortality data are virtually complete for survivors who remained in Japan.

High-quality tumor registries in both Hiroshima and Nagasaki allow the study of site-specific incidence with reasonable reliable diagnostic data.
LS Study cohort is less subject to potential bias from confounding than many other exposed cohorts because of a primary determinant of dose is distance from hypocenter, with a steep gradient of dose as function of distance.
Special studies involving subgroups of the LS Study have provided clinical data, biological measurements of radiation exposure on other health outcomes than cancer.
The LLS choort of A-bomb survivors serves as the single most important source of data for evaluating risks at low and moderate doses.
Although cancer is is the main late effect that has been demonstrated in the survivors studies, several sudies had adressed the effects on other health outcomes including benign tumors and mortality from other causes of death other than cancer.

Source: Health risks from exposure to low levels of Ionizing Radiation
BEIR VII Phase 2.
National research Council of the National Academies.

[Dayman]

I mean if you walked around their with a geiger counter would it be higher than normal?

[Rhaegar1]

I must say I don't really know, I think the actual activity is still not back to what it was before the bombings but I think that it didn't take as long as you might before it was safe to repopulate the area.

You have to keep in mind that there is a large variety in the normal background radiation anyway (due to cosmic radiation and terrestial radiation) for example is the average dose in the netherlands about 50 nanogray (gray=absorbed energy per unit of mass) per hour but there are also places in the world where this can be up too 25 microgray per hour. so that's 500 times as much!

[Gungalley]

Not to mention countless birth defects and permanent genetic damage.

[Rhaegar1]

That's an interesting study, it seems my source is sadly lacking much information about leukemia and is mostly refering to solid cancer since those numbers are much higher, the 8 percent you mention seems roughly equivalent to the numbers I read.
The only thing really mentioned about leukemia is a number of only 249 deaths in total (from the 86572) which is quit small and probably the reason why this book isn't going into that any further considering that it was only a side step in the course. I have no medical background so I don't know the numbers of non-lethal cancers and leukemia cases but from a mathemetical point of view it seems to me that only +- 250 cases is quit small for very accurate estimates in such a 'statistics heavy' area as this.

Anyhow the only point I tried to make was that in my opinion the stochastic (late) effects of the nuclear bombings was far less compared to the determenistic effects (imidiate/fast) then I was allways led to believe.