Particulate matter emissions associated with marcellus shale drilling waste disposal and transport

ABSTRACT

This study models emissions quantities and neighboring exposure concentrations of six airborne pollutants, including PM₁₀, PM_2.5, crystalline silica, arsenic, uranium, and barium, which resulted from the disposal of Marcellus shale drill cuttings waste during the 2011–2017 period. Using these predicted exposures, this study evaluates current setback distances required in Pennsylvania from waste facilities. For potential residents living at the perimeter of the current setback distance, 274 m (900 ft), a waste disposal rate of 612.4 metric tons per day at landfills (the 99th percentile in record) does not result in exceedances of the exposure limits for any of the six investigated pollutants. However, the current setback distance can result in exceedance with respect to the 24-hr daily concentration standards for PM₁₀ and PM_2.5 established in the National Air Ambient Quality Standards (NAAQS), if daily waste disposal rate surpasses 900 metric tons per day. Dry depositions of barium-containing and uranium-containing particulate matter should not be a danger to public health based on these results. To investigate the air quality impacts of waste transportation and the potential for reductions, this article describes an optimization of landfill locations in Pennsylvania indicating the potential benefits in reduced environmental health hazard level possible by decreasing the distance traveled by waste disposal trucks. This strategy could reduce annual emissions of PM₁₀ and PM_2.5 by a mean of 64% and reduce the expected number of annual fatal accidents by nearly half, and should be considered a potential risk management goal in the long run. Therefore, policy to limit or encourage reduction of distances traveled by waste removal trucks and manage setback distances as a function of delivered waste quantities is merited.     

Spatial analyses of groundwater level differences using geostatistical modeling

The purpose of this study was to determine and evaluate the spatial changes in the depletion of groundwater level differences by using geostatistical methods based on data from 58 groundwater wells during the period from April 1999 to April 2008 in the study area. Geostatistical methods have been used widely as a convenient tool to make decision on the management of groundwater levels. To evaluate the spatial changes in the level of the groundwater, geographic information system is used for the application of universal kriging method with cross-validation leading to the estimation of groundwater levels. The resulting prediction mappings identify the locations of groundwater level fluctuations of the study area. The average range of variogram (spherical model) for the spatial analysis is about 9,200 m. Results of universal kriging for groundwater level differences drops were underestimated by 15 %. Cross-validation errors are within an acceptable level. The maps show that this area of high decrease of groundwater level is located at the southwest. Kriging model helps also to detect sensitively risk prone areas for groundwater withdrawing. Such areas must be protected with an effective management procedure for future groundwater exploitations.