[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: background vs man-made emmissions - fallout
Hiroshima was an air blast>
Tom Lashley
LashleyT@DTEenergy.com
Bernard L Cohen wrote:
> For some perspective on long term exposures from the Hiroshima bomb, I
> remember a conversation with a scientist who was among the first to enter
> Hiroshima after the bombing, with the job of using survey meters to look
> for radioactivity. He was finding nothing for some time until he got
> excited by a substantial positive reading. On investigating it, he found
> that it was a medical source. Apparently, within the limits of survey
> meters at that time, there was essentially no radioactivity from fallout
> in Hiroshima.
>
> Bernard L. Cohen
> Physics Dept.
> University of Pittsburgh
> Pittsburgh, PA 15260
> Tel: (412)624-9245
> Fax: (412)624-9163
> e-mail: blc+@pitt.edu
>
> On Sun, 30 Apr 2000 GlennACarlson@aol.com wrote:
>
> > I thought the existence of fallout at Hiroshima was well established, though
> > the levels and the health impact are still debated. Is this incorrect?
> >
> > Consider also the following:
> >
> > Health Phys 1996 Sep;71(3):340-6; 137Cs concentration in soil samples from an
> > early survey of Hiroshima atomic bomb and cumulative dose estimation from the
> > fallout. Shizuma K, Iwatani K, Hasai H, Hoshi M, Oka T, Okano M Faculty of
> > Engineering, Hiroshima University, Japan.
> >
> > Low background gamma-ray measurement has been performed to determine the
> > 137Cs content in soil samples collected in a very early survey of the
> > Hiroshima atomic bomb. These soil samples were collected just 3 d after the
> > explosion within 5 km from the hypocenter and were not exposed to the global
> > fallout from nuclear weapon tests. Out of 22 samples, 137Cs was detected for
> > 11 samples, and their radioactivities ranged from 0.16-10.6 mBq g-1 at the
> > time of the measurement. A comparison of the 137Cs deposition with the
> > rainfall area within Hiroshima city indicates that the rainfall area was
> > wider than the previously proposed one. Cumulative exposure by the fallout
> > has been estimated to be 0.31 mC kg-1 (0.12 R) in Hiroshima city except for
> > the heavy fallout area and at most 1.0 mC kg-1 (4 R) in the heavy fallout
> > area.
> >
> >
> > J Radiat Res (Tokyo) 1991 Mar;32 Suppl:32-9; Studies of radioactivity
> > produced by the Hiroshima atomic bomb: 2. Measurements of fallout
> > radioactivity. Hasai H, Hoshi M, Yokoro K Faculty of Engineering, Hiroshima
> > University, Japan.
> >
> > Three studies of fallout measurements were reviewed for the discussion of
> > possible radioactivity intake from the Hiroshima atomic bomb. The first study
> > discussed correlations between enriched 234U and 137Cs specific activities
> > from the measurement of soil samples collected in the "black rain" area. The
> > second study measured 137Cs activity on the rock and roof tile samples
> > collected in the hypocenter area immediately after the explosion. Some of the
> > rock and roof tile samples collected near the hypocenter had a small but
> > detectable amount of 137Cs activity. However, it has been determined that
> > 137Cs exposure, for example, was negligible compared with DS86 dose
> > estimates, since these activity levels were low. The third study detected
> > 90Sr activity in some of the specimens of human bones exhumed on Ninoshima
> > Island. This study compared the difference in activity between the bone head
> > and shaft, with higher activities obtained in the bone head. This fact
> > suggests a short intake period for this activity, however, the levels of 90Sr
> > contamination were too low to allow a discussion of the exposure risks.
> >
> > In a message dated 4/30/2000 12:37:11 PM Central Daylight Time,
> > frantaj@aecl.ca writes:
> >
> > > Subj: RE: background vs man-made emmissions - fallout
> > > Date: 4/30/2000 12:37:11 PM Central Daylight Time
> > > From: frantaj@aecl.ca (Franta, Jaroslav)
> > >
> > > Thanks for the information Glenn....
> > >
> > > ....but I'm very dubious about its veracity.
> > >
> > > The doses absorbed by the bombing victims are estimated to have been in the
> > > range of a few hundred rem (depending on location, any shielding effects,
> > > etc. (deaths were due to CONVENTIONAL thermal burns from the light flash
> > and
> > > from building fires, and from other forms of physical trauma, NOT due to
> > ARS
> > > !! ).
> > >
> > > Even if all of this exposure were due to neutrons - which it certainly was
> > > not (there was a large gamma constituent) - it would have been very, very
> > > far from sufficient to cause "High levels of residual radiation ...on the
> > > ground...in the
> > > > form of induced radioactivity produced secondarily as a result of the
> > > > nuclear reaction of neutrons."
> > > >
> > > Trust me, its BS.
> > > We have the recent example of the Tokaimura criticality accident, where the
> > > absorbed doses were about ten times higher than those in Japan (actual
> > > deaths from ARS), yet even there the levels of neutron-induced
> > radioactivity
> > > inside the building were negligible ( escaped airborne radioactivity was
> > due
> > > to vapours issuing from the precipitation tank containing the critical
> > > solution of 20% U235 & FPs ).
> > >
> > > Radioactive fallout rain in Japan reportedly occurred, but far outside the
> > > cities, after much dilution.
> > > Any fallout soot from "intense firestorms" would NOT have been radioactive,
> > > for the reasons given above.
> > >
> > > Glenn, the quotations you provide look to me like the same sort of
> > > self-delusion that is practiced in the Ukraine and Belarus on account of
> > the
> > > Chernobyl disaster. Its amazing how many people believe THAT nonsence (tens
> > > of thousands dead as a result, etc.). I take it you're NOT one of them ?
> > >
> > > Thanks again,
> > >
> > > Jaro
> > > frantaj@aecl.ca
> > >
> > > > ----------
> > > > From: GlennACarlson@aol.com[SMTP:GlennACarlson@aol.com]
> > > > Reply To: radsafe@romulus.ehs.uiuc.edu
> > > > Sent: Sunday April 30, 2000 12:01 PM
> > > > To: Multiple recipients of list
> > > > Subject: Re: background vs man-made emmissions - fallout
> > > >
> > > > _From http://www.city.hiroshima.jp/C/City/ABombDamage/07.html
> > > >
> > > > "7.2 Residual Radiation
> > > >
> > > > High levels of residual radiation were present on the ground for a
> > certain
> > > >
> > > > period of
> > > > time starting one minute after the explosion. Residual radiation came in
> > > > the
> > > > form of
> > > > induced radioactivity produced secondarily as a result of the nuclear
> > > > reaction of
> > > > neutrons when initial radiation collided with the soil and building
> > > > materials, and it
> > > > also came from nuclear fission products and unfissioned uranium scattered
> > > > by
> > > > the
> > > > bomb.
> > > >
> > > > It is quite likely that anyone entering the area within 1 km of the
> > > > hypocenter within
> > > > 100 hours after the explosion to search for people or help with relief
> > > > efforts was
> > > > affected by radiation coming from the soil and other such places due to
> > > > induced
> > > > radioactivity. In addition, soot and dust saturated with induced
> > radiation
> > > >
> > > > from nuclear fission products and unfissioned uranium scattered at the
> > > > time
> > > > of the bombing were carried high into the atmosphere and later fell to
> > the
> > > >
> > > > ground as radioactive fallout, giving rise to further possibilities for
> > > > contamination.
> > > >
> > > > 7.3 Black Rain
> > > >
> > > > As the downtown area erupted in huge fires after the explosion, intense
> > > > firestorms
> > > > and whirlwinds developed. After 20-30 minutes, black rain began to fall
> > in
> > > > a
> > > > wide area
> > > > stretching from downtown to the northwest.
> > > >
> > > > Large amounts of fallout, referred to as "Ashes of Death" were contained
> > > > in
> > > > the rain
> > > > in the form of radioactive soot and dust and caused contamination even
> > in
> > > > areas
> > > > remote from the hypocenter.
> > > >
> > > > According to a study after the bombing, heavy rain fell in a 19km x 11
> > km
> > > > area and
> > > > light rain fell in a 29km x 15km area, but there have been testimonies
> > > > that
> > > > black rain
> > > > fell in places outside these areas as well."
> > > >
> > > > Glenn A. Carlson, P.E.
> > > > glennacarlson@aol.com
> > > >
> > > > > Subj: RE: background vs man-made emmissions - fallout
> > > > > Date: 4/30/2000 7:18:00 AM Central Daylight Time
> > > > > >
> > > > > > Regarding your comment, what about exposure from fallout?
> > > > > >
> > > > > > Glenn A. Carlson, P.E.
> > > > > > glennacarlson@aol.com
> > > > > >
> > > > ************************************************************************
> > > > > >
> > > > > Reply : as far as I know, there wasn't any, since in both cases it
> > was
> > > > a
> > > > > high-altitude explosion. This was confirmed by radiation surveyors on
> > > > the
> > > > > ground there soon after the explosions.
> > > > >
> > > > > Jaro
> > > > > frantaj@aecl.ca
> > > > > *************************************
> > >
> > ************************************************************************
> > The RADSAFE Frequently Asked Questions list, archives and subscription
> > information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
> >
>
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html