ENHANCED DEPOSITION OF RADON DAUGHTER NUCLEI IN THE VICINITY OF POWERFREQUENCY ELECTROMAGNETIC-FIELDS

We report the attraction of radon daughter nuclei in normal domestic r oom air to everyday sources of power frequency electromagnetic fields. TASTRAK plastic track detectors were used to measure alpha-emission f rom the radon (Rn-222) daughters Po-218 and Po-214 close to 50-Hz main s frequency power cables and domestic appliance leads. We observed tha t wires carrying mains frequency potential attract radon daughter nucl ei in a manner visually similar to the attraction of iron filings to a magnet. Increased deposition of up to a factor of 18 was observed. Fu rther experiments designed to simulate the effect of overhead power li nes at ground level showed large scale variations in local plateout an d airborne concentration of radon daughters. The effects appear to be due to interactions of the electric component of the EM-field with bot h the ultrafine and attached fraction of radon daughter aerosols. Thre e mechanisms have been examined. First, aerosols instantaneously polar ize in sympathy with the electric component of an applied mains freque ncy EM-field and as a result may migrate up strong E-field gradients. This effect is however quite weak and may only affect larger aerosols in strong field gradients. Second, charged aerosols oscillate in a 50- Hz field and in the case of the ultrafine fraction this may lead to si gnificantly increased plateout. Third, there is the possibility that o scillation of charged aerosols induces fluctuations in the magnitude o f the instantaneous charges carried and this results in a diffusive-li ke motion along the field lines. The effect on dose to body organs is considered. Enhanced plateout on the skin is likely, increasing the do se to the basal layer. The dose to internal organs is governed initial ly by inhalation and lung deposition of radon daughters. Therefore inc reased local concentration in room air could lead to increased dose by inhalation. E-fields are heavily attenuated by the human body and bod y values in tissue of no more than 10(-4) of the external field streng th have been suggested. Nevertheless calculations suggest that under e xposure to strong external fields this may still be sufficient to alte r the deposition pattern of the charged component of the ultrafine fra ction in the bronchial region. In contrast it is unlikely that interna l electric fields could significantly affect the attached radon daught ers. In this context the lack of measurements of residual E-fields in the cavities of the mouth, pharyngeal and bronchial regions is of cons iderable importance and should be addressed. We believe that the obser vations may have implications for the apparent enigma that there is no persuasive biological evidence to show that power frequency electroma gnetic fields can influence any of the accepted stages in carcinogenes is. On the contrary, the observations show that EM-fields can concentr ate in their vicinity a cocktail of radon daughter nuclei, a known car cinogen, and presumably other potentially harmful agents.