[ RadSafe ] Uranium and genotoxicity

Otto G. Raabe ograabe at ucdavis.edu
Sat Jun 7 16:08:27 CDT 2008

>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

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