Berislav Momčilović

Seasonality of 214Bi activity in the human body and of 222Rn concentration in home ambient air

We studied the seasonal variation of the environmental radon progeny 214Bi activity in the whole bodies (WB) of women and men participating in community-based studies at the Grand Forks Human Nutrition Research Center (GFHNRC), the 214Bi background activity of the GFHNRC whole body counter (WBC) steel room, and ambient air 222Rn concentration in the homes of Grand Forks residents, over the 1988–2004 time period. In this cross-sectional epidemiological study, 214Bi activity in women and men, in the WBC steel room, and 222Rn concentration in resident homes fluctuated such that the highest values were observed in winter and the lowest in summer, respectively. 214Bi activity in the WB of human subjects was higher in women who have more 214Bi activity per unit mass than men. Apart from their common seasonal pattern, human WB 214Bi activity (lnBq) was comparatively higher than that for the ambient air 222Rn activity in a human-equivalent volume of 72 L.

Natural distribution of environmental radon daughters in the different brain areas of an Alzheimer Disease victim

BackgroundRadon is a ubiquitous noble gas in the environment and a primary source of harmful radiation exposure for humans; it decays in a cascade of daughters (RAD) by releasing the cell damaging high energy alpha particles.ResultsWe studied natural distribution of RAD 210Po and 210Bi in the different parts of the postmortem brain of 86-year-old woman who had suffered from Alzheimers disease (AD). A distinct brain map emerged, since RAD distribution was different among the analyzed brain areas. The highest RAD irradiation (mSv·year-1) occurred in the decreasing order of magnitude: amygdale (Amy) >> hippocampus (Hip) > temporal lobe (Tem) ~ frontal lobe (Fro) > occipital lobe (Occ) ~ parietal lobe (Par) > substantia nigra (SN) >> locus ceruleus (LC) ~ nucleus basalis (NB); generally more RAD accumulated in the proteins than lipids of gray and white (gray > white) brain matter. Amy and Hip are particularly vulnerable brain structure targets to significant RAD internal radiation damage in AD (5.98 and 1.82 mSv·year-1, respectively). Next, naturally occurring RAD radiation for Tem and Fro, then Occ and Par, and SN was an order of magnitude higher than that in LC and NB; the later was within RAD we observed previously in the healthy control brains.ConclusionNaturally occurring environmental RAD exposure may dramatically enhance AD deterioration by selectively targeting brain areas of emotions (Amy) and memory (Hip).

Comment on the Capstone Depleted Uranium (DU) Aerosol Characterization and Risk Assessment Study.

Dear Editors: WE NOTED that nowhere in the issue of Health Physics, March 2009, devoted to “The Capstone Depleted Uranium (DU) Aerosol Characterization and Risk Assessment Study” (Parkhurst and Guilmette 2009) were nanoparticles considered or even mentioned. The smallest particles considered were approximately 0.7 m in diameter (Holmes et al. 2009). Perhaps DU atoms may have entered the brain via olfactory pathways (Tjälve and Henriksson 1999) or carbon nanoparticles, i.e., buckyballs or fullerenes (Kroto et al. 1985), may have been produced when DU burned as the armor piercing shells struck a target (Krupka et al. 2009). Recent research has indicated the possibility of nanotoxicity to the lung and via lungs to other body compartments. (Oberdörster et al. 2005). One may ask, is it possible that the carbon fullerenes could also capture individual DU molecules that can be taken in the nasal mucosa and transported through the olfactory nerve further into the brain (Persson et al. 2003; Dorman et al. 2009)?