Wikipedia:Requests for mediation/Depleted uranium and related articles/Total inhalation exposure

How accurately will isotope ratio urine studies which depend on particulate uranium aerosol remaining undissolved in the lung measure total inhalation exposure?

Request for clarification

Surely urine studies depend on aerosol particles dissolving in the lungs? Physchim62 (talk) 00:08, 22 February 2006 (UTC)

The urine studies taking place fifteen years after exposure assume that some uranium has remained undisolved as quadravalent ceramic UO₂ particles, because other tissues don't retain as much U-238 as the particulate inhalation exposure victims have in their lungs. The issue is that many people are exposed to hexavalent uranyl oxide without inhaling any particulate UO₂ or U₃O₈ --James S. 06:54, 22 February 2006 (UTC)

OK, so if I get you correctly, you are more concerned (for the moment) about the chemical toxicity of absorbed uranium than the possible radiological toxicity of the inhaled-but-undissoved UO₂ particles? (I would guess that after fifteen years any U₃o₈ would have been absorbed, leaving only UO₂) Physchim62 (talk) 07:04, 22 February 2006 (UTC)

Exposure to soluble uranium compounds would presumptively lead to a quicker spike in urine uranium, but lower long-term urine uranium concentrations than comparable exposures to insoluble uranium particulates. Exposure to sufficient amounts of soluble uranium over sufficiently short time periods would lead to urine concentrations exceeding the threshold for nephrotoxicity. As no increases in specific types of kidney damage have been observed amongst Gulf War veterans, it has been surmised that these thresholds were never reached, thereby placing an upper limit on actual exposures received in the Gulf War. Urine isotope ratios of uranium varying from natural ratios are reliable proof of exposure to depleted uranium in the immediate or distant past. Dr U 03:26, 23 February 2006 (UTC)

I disagree; the amount of UO₃(g) produced must be measured or calculated before the level of accuracy from methods depending on the presense of insoluble compounds can be determined. --James S. 17:48, 26 February 2006 (UTC)

Sources to back up this assumption? Dr U 17:58, 26 February 2006 (UTC)

Morrow et al. '72: less than five day's biological half time in the lungs for UO₃ particles -- and any lung text which will tell you that condensing gasses are absorbed directly into the bloodstream. You aren't going to get dissolutions five years later from gasses; probably not even detectable amounts after five days, and since they disperse diferently than aerosol particles, there's going to be divergence between the extent to which any given person was exposed to either form. By the way, the diffusion rate in open explains the diference in hexavalent compound detection Salbu et al. talk about. --James S. 07:20, 27 February 2006 (UTC)