Community airborne particulate matter from mining for sand used as hydraulic fracturing proppant

Abstract

Field and laboratory studies were conducted to evaluate the impact of proppant sand mining and processing activities on community particulate matter (PM) concentrations. In field studies outside 17 homes within 800 m of sand mining activities (mining, processing, and transport), respirable (PM4) crystalline silica concentrations were low (< 0.4 μg/m3) with crystalline silica detected on 7 samples (2% to 4% of mass). In long-term monitoring at 6 homes within 800 m of sand mining activities, the highest daily mean PM concentrations observed were 14.5 μg/m3 for PM2.5 and 37.3 μg/m3 for PM10, although infrequent (< 3% of time), short-term elevated PM concentrations occurred when wind blew over the facility. In laboratory studies, aerosolized sand was shown to produce respirable-sized particles, containing 6% to 19% crystalline silica. Dispersion modeling of a mine and processing facility indicated that PM10 can exceed standards short distances (< 40 m) beyond property lines. Lastly, fence-line PM and crystalline silica concentrations reported to state agencies were substantially below regulatory or guideline values, although several excursions were observed for PM10 when winds blew over the facility. Taken together, community exposures to airborne particulate matter from proppant sand mining activities at sites similar to these appear to be unlikely to cause chronic adverse health conditions.