Re: uranium in urine analysis

["Christoph Hofmeyr" <Christoph_Hofmeyr@NNR.CO.ZA>]

Dov, Otto and Radsafers,

 Because I omitted a qualifying phrase regarding uptake, my formulation

wrongly seemed to imply concentration in body fluid above the intake

concentration of uranium of 9 mg/l.   Obviously,  the gut uptake factor

(directly into the body fluids) should be factored in, but water loss from

the body would also be through other channels, e.g. breathing and sweating,

thereby effecting a concentration.  The critical factor surely is chronic

intake at this level of concentration, which cannot reasonably be compared

with an acute intake.   I could be wrong , but I would have assumed that

uranium dissolved in water is of soluble type, with a gut transfer factor

of several percent.   Since soluble uranium is excreted faster, I tend to

agree the body would probably manage to keep the concentration of uranium

at sub-lethaI levels via the kidneys.    I  think Otto Raabe explains a

mechanism of concentration in the longer term.   The term 'poison' is

rather relative -  is an unhealthy concentration a poison?

Chris Hofmeyr

chofmeyr@nnr.co.za



Dov wrote:





>Dear Chris and radsafers



>At 08:29 27/03/01 +0200, Christoph Hofmeyr wrote:

>>

>>Radsafers,

>>I can understand Franz's concern.  You are talking uranium intake in

water

>>of up to 9 mg/l, and there is bound to be further concentration in the

body

>>fluids.



>In fact uranuim absorbed to the bloodstream will  move to the extracelluar

>space. Then about 50-60% are cleared rather rapidly by the urine , 15-20%

>are retained in the kidneys this fraction may lead to kiney damage), and

>about  20% are retained in the bones. (This is the ICRP-30 uranium model,

>newer models do not differ significantly for this disscussion). I don't

see

>where the U will be "further concentrated.



 >>If I am not mistaken,  3 mg/l was regarded as a maximum

>>sustainable uranium excretion rate in urine, whereas 10 mg/l would lead

to

>>rapid kidney damage and failure.



>Butterworth ("Human data on uranium exposure" in symposium on occupational

>health expirience and practice in the uranium industry held in New York

Oct

>15-17 1958 - HASL-58 pp41-46, 1958) described a man who drank about 1 gr

of

>uranil nitrate .  Urine U concentrations were up to 10 mg/l. Beside

>transient proteinuria (for about 24 hours), no damage to the kidney was

>observed.



  >>The lethal body burden of dissolved

>>uranium is supposedly 1 mg/kg of body mass (70 - 100 mg total for an

>>adult).



>More accurately this is the assumed human lethal dose  of soluble uranium

>(uranyl nitrate , uranyl fluoride etc.) injected intravenously. The

ICRP-30

>uranium model assume a 0.05 factor for the absorbtion form the GI tract

for

>soluble uranium.

>Uranium in well-water is in insoluble oxide form, the absorbtion factor is

>0.002. Therefore from every liter of water less than 20 micrograms are

>abosrbed.



>>  That 'water' is poison.



>Not in this concentration of U. I would not let my kids drink them, but in

>microgram/liter x 50 x 70 to get 70 mg for an adult..) , as fast as

>possible...



>Dov (Dubi) Brickner    MD

>Beer-Sheva  ISRAEL



>brickner@in.zahav.net.il



Otto Raabe wrote:



>At 10:59 PM 3/27/01 +0200, Dov Brickner wrote:

>>In fact uranium absorbed to the bloodstream will  move to the

extracelluar

>>space. Then about 50-60% are cleared rather rapidly by the urine , 15-20%

>>are retained in the kidneys this fraction may lead to kidney damage), and

>>about  20% are retained in the bones. (This is the ICRP-30 uranium model,

>>newer models do not differ significantly for this disscussion). I don't

see

>>where the U will be "further concentrated.

****************************************************************

>March 27, 2001

>Davis, CA



>Since the retention half-time for uranium in bone is quite long, the

>uranium concentration in the bone will continue to increase over time with

>daily ingestion in contaminated water until it reaches some equilibrium

>level after several years and this will result in higher average

>concentrations in other tissues including blood and kidneys, although the

>main concentrating effect is in the bone.



>Otto



>Prof. Otto G. Raabe, Ph.D., CHP

>Institute of Toxicology & Environmental Health







************************************************************************

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line.



------------------------------