A Landscape-Process Approach to Assess Potential Human Exposure to Erionite-Rich Dust in Northern Nevada, USA

Erionite is a naturally occurring fibrous mineral that, when inhaled, may be up to 800 times more carcinogenic than asbestos. Erionite exposure is associated with lung cancer and mesothelioma and was previously identified as the cause of the malignant mesothelioma epidemic in Cappadocia, Turkey. The goal of our study is to identify the distribution of erionite-bearing rocks throughout the hydrogeomorphic landscape of northern Nevada (NV) to assess the potential inhalation exposure to fibers in airborne dust. The geologic history of NV has produced an ideal setting for erionite formation, with erionite beds up to several meters thick associated with lacustrine depositional environments, where volcanic ash settled into alkaline waters of shallow lakes.

Geologic samples were collected in Eastgate, NV from volcanic tuff-rich lacustrine rocks and fluvial sediment samples from nearby dry streambeds. Using these samples, we developed an erionite-dust potential map based on the distribution of erionite from primary sources and eroded erionite deposited throughout the hydrogeomorphic landscape. Erionite fibers were isolated from rock and sediment samples using gravity settling in isopropanol and identified based on mineral morphology via scanning electron microscopy and chemical properties using energy dispersive X-ray spectroscopy, X-ray diffraction, and electron probe microanalysis. Erionite was identified in all rock and sediment samples from Eastgate, and initial results show that erionite concentrations in fluvial sediment reduce with increasing distance from primary source areas. Initial results of the erionite-dust potential assessment will be paired with other geomorphic factors, including landform type, soil characteristics, and vegetation density to develop a hazard map of erionite dust emission susceptibility. This map will be used to assess potential human exposure to erionite in the natural environment at regional scales and will ultimately be combined with genetic data and medical records to investigate the health outcomes of northern Nevadans as part of the Healthy Nevada Project (HNP). The HNP is a large (>50,000) all-comers population health study across Nevada that focuses on identifying associations between disease, genetics, environment, and social health determinants.