Rastus2: This is all a bunch of B.S. scare tactics. I am a...

Rastus2: This is all a bunch of B.S. scare tactics. I am a professional environmental human health risk assessor. I have run the RESRAD DOE computer model to assess risks from exposures to alpha and gamma radionuclide emissions for several studies of groundwater, soil, indoor air, and buidling materials.

LAMP will not be a problem for radionuclide exposure from radon gas to nearby residents.

Here is the essence of the problem with these scare tactics posted by the SMSL: Gamma emissions are expected to be of low significance to carcinogenicity because the impact decreases with the inverse square of distance from the source. However, alpha particle emission is ONLY a problem if there is a migration pathway which leads to direct inhalation of an AIRBORNE radionuclide which can thereby experience alpha-decay within the lungs. Infiltration of radon gas into homes from naturally occurring rocks in the subsurface is one example.

Gamma radiation is associated with exposure to either U-238 or Th-232 decay chains, both of which are present at low levels in LAMP residues. However, gaseous radon-220, which is part of the Th-232 decay chain, only has a half life of 55 sec before it decays to a solid element, which won't migrate through air. So Th-232 won't really be a problem for radon inhalation because it never reaches the target lung in the short amount of time it has to migrate as an airborne radionuclide.

On the other hand, Rn-222 arises from the U-238 decay chain, and has a half life of 3.8 days, which allows a longer time for airborne migration to reach a person's breathing zone from a given solid particle source residue.

It is noteworthy that U-238 levels in LAMP residues are relatively low (200 Bq/kg) compared to those in the cited Swedish study (600 to 5000 Bq/kg). However, it is Ra-226 that is an intermediate to production of other decay chain progeny, and it is not known whether processing extraction of REEs alters the natural secular equilibrium ratio of U-238 to Ra-226.

Hence, it is unlikely that members of the public would be exposed to enough airborne radon to be harmful, unless they were located very, very close to a source of dust such that they would be inhaling the particulate dust itself as opposed to the radon decay product released by the dust.

I elaborated upon this issue in a post on the Yahoo message board where we were speculating about the safety of using LAMP residues to make building products, either gypsum wallboard or concrete for roads (the latter seemed like a better idea).

http://messages.finance.yahoo.com/Stocks_%28A_to_Z%29/Stocks_L/threadview?m=ms&bn=70393&tid=30810&mid=30951&tof=-1&rt=1&frt=2&off=1

http://messages.finance.yahoo.com/Stocks_%28A_to_Z%29/Stocks_L/threadview?m=ms&bn=70393&tid=30810&mid=30884&tof=-1&rt=1&frt=2&off=1