# [ RadSafe ] Concerning Rizzini's claim of one ug U-238

Lantzelot Mattias.Lantz at physics.uu.se
Mon Oct 28 02:28:36 CDT 2013

```Otto,

I think your result is off by a factor of ten, the conversion factor
from Ci to Bq looks a bit odd.
But it does not change the general conclusion regarding Rizzini's statement.
My approach (I will appreciate any spotted errors):

1 Ci = 3.7*10^10 Bq
1 uCi = 37000 Bq
0.5 uCi = 18500 Bq

lam238 = log(2)/(4.5*10^9 yrs * 365 days * 24 hrs * 3600 s)
N238 = 1*10^(-6)  * 6.022*10^23 / 238
A238 = lam238 * N238 = 0.012 Bq/ug

18500 Bq / 0.012 Bq/ug = 1.5 g

Mattias

--
Mattias Lantz - Researcher
Department of Physics and Astronomy
Division of Applied Nuclear Physics
Uppsala University, Box 516
SE - 751 20, Uppsala, Sweden
email:  mattias.lantz at physics.uu.se

On 10/28/2013 08:14 AM, Otto G. Raabe wrote:
> Rizzini has been quoted as saying that one microgram of U-238 can kill
> a person. An article from March 31, 2011, Rizzini once again claims
> that 1 microgram of uranium is enough to kill a person:
>
> _PLEASE CHECK MY MATH_: According to ICRP-2 (page 81) a human can have
> a body burden of U-238 of 0.5 microcuries without lifetime risk.
> That is 0.5 microcuries times 3.7 x 10^9 Bq/uCi = 1.9 x 10^9 Bq. One
> microgram of U-238 equals 0.012 Bq.
>
> Hence, according to ICRP-2 a human could have an internal burden of
>
> Am I missing something here? Please check my math.
>
> Otto
>
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> Center for Health & the Environment
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