LEGACY URANIUM MINES: WHAT ARE THE HUMAN HEALTH RISKS OF WINDBLOWN DUSTS CONTAMINATED WITH HEAVY AND TRANSITION METALS? (Invited Presentation)

Legacy mines and waste from hardrock mining pose risks of contaminating surrounding regions with heavy and transition metal toxicants if not properly remediated. Over 500 abandoned uranium mines (AUM) exist on Navajo Nation, alone, with 1000’s more throughout the Western U.S.; uncertainty exists regarding the potential for aeolian resuspension of particulates from these sites and downwind impacts on human health. We have undergone research campaigns at 2 partially-remediated AUM sites to address potential exposures and toxicity in rodent models using a mobile inhalation exposure research laboratory. Extracting particulates directly from mine sites (using laboratory-based approaches) has revealed elevated levels of metals, such as uranium and vanadium, that are more potently toxic to the lungs. Such particulates taken directly from sites promote greater lung inflammation, injury and oxidative stress than do particulates derived from nearby regions that have not been impacted by mining. However, atmospheric collection nearby these sites, along with rodent exposures to naturally-occurring ambient particulate matter, revealed no evidence of metals transport from the two AUMs studied. Meteorological factors (i.e., wind direction) largely favored the safety of local populations. Thus, while the sediments in the regions of AUMs have contaminant metals and are more toxic, resuspension of such sediments was not a measurable phenomenon in the ambient airshed, even immediately adjacent to a ~3000-acre AUM. These studies support ground covering as an essential component of remediation, but do not impugn current methods as unsafe. The results do not address other pathways of contaminant metal transport and exposure, such as drinking water or agricultural contamination.