[ RadSafe ] Uranium and genotoxicity

[James Salsman]

Dear Dr. Raabe:

Leach and his associates did not measure genotoxicity, even though
karyotyping was readily available to them.  They also did not measure
reproductive toxicity.

Why did Leach and his associates ignore the 1949 work of Maynard and Hodge?

Maynard, EA.; Hodge, HC. Studies of the toxicity of various uranium
compounds when fed to experimental animals. In: Voegtlin C, Hodge HC.
, editors. Pharmacology and Toxicology of Uranium Compounds. New York:
McGraw-Hill Book Company, Inc.; 1949. pp. 309–376.

James Salsman

On Sat, Jun 7, 2008 at 2:08 PM, Otto G. Raabe <ograabe at ucdavis.edu> wrote:
> June 7, 2008
>
> Over half century of biological studies and the body of scientific
> literature has shown that uranium is probably one of the least toxic of all
> the heavy metals. It is essentially inert in the human body, sequesters in
> the skeleton, and is slowly excreted through the kidneys. High uptakes can
> temporarily interfere with kidney function associated with deposition in the
> kidney tubules and glomeruli, but uranium is not readily taken up by or
> metabolized in the body.
>
> While in graduate school at the University of Rochester I had the
> opportunity to observe the inhalation studies being conducted with uranium
> oxide using various animal species. The Rochester studies began in the 40's
> as part of the Manhattan project and were still in progress when I was a
> graduate student in the 60's. Two of the key papers summarizing the uranium
> dioxide inhalation studies were published by Leonard Leach and his
> associates. The references are Heath Physics  18: 599-612 (1970) and Health
> Physics 25: 239-258 (1973). The opening sentence of the Abstract of the 1973
> paper states: "Inhalation studies show that dogs, monkeys and rats can
> breathe a natural uranium dioxide (UO2) aerosol of approximately 1 um mass
> median particle diameter at a mean concentration of 5 mg U/m3  (25 x TLV or
> 28 x MPCa), for periods as long as 5 yr with little evidence of serious
> injury."
>
> Natural and depleted uranium are chemically and biologically identical in
> their behavior and radiologically very similar. There is really no basis for
> claims of inordinate hazards from exposure to oxides of uranium.
>
> References: "Handbook of the Toxicology of Metals", Friberg et al.(1990),
> "Uranium, Plutonium, Transplutonium Elements", Hodge et al. (1973), "A five
> year inhalation study with natural uranium dioxide", HEALTH PHYS 25, 230-258
> (1973), "Depleted Uranium In The Gulf": http://www.gulflink.osd.mil/du_ii
>
> **********************************************
> Prof. Otto G. Raabe, Ph.D., CHP
> Center for Health & the Environment
> University of California
> One Shields Avenue
> Davis, CA 95616
> E-Mail: ograabe at ucdavis.edu
> Phone: (530) 752-7754   FAX: (530) 758-6140
> ***********************************************