--> --> Evaluating Sources of Groundwater Quality Variability in Residential Water Wells for Pre-Drill Sampling
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Evaluating Sources of Groundwater Previous HitQualityNext Hit Variability in Residential Previous HitWaterNext Hit Wells for Pre-Drill Sampling

Abstract

Significant concern has been expressed regarding the potential impact of shale gas extraction on surrounding drinking Previous HitwaterNext Hit resources. However, determining whether changes in groundwater chemistry (e.g., methane, salts, etc.) are natural in origin or caused by drilling operations can be difficult, particularly when a) different sampling and analytical methodologies are employed and b) Previous HitwaterNext Hit Previous HitqualityNext Hit can vary naturally over time due to various factors (e.g., intensity of residential Previous HitwaterNext Hit use). To better understand the sources of variability in Previous HitwaterNext Hit Previous HitqualityNext Hit in residential Previous HitwaterNext Hit wells in NE Pennsylvania, an area of active Marcellus shale gas extraction, two field studies were completed at nine residential Previous HitwaterNext Hit wells to evaluate the significance of sampling methodology and temporal variability on Previous HitwaterNext Hit Previous HitqualityNext Hit results. For the sampling variability study, the effect of different sample collection methods and sampling containers on dissolved gas concentrations, as well as the effect of purge volume on dissolved gas concentrations, general Previous HitwaterNext Hit Previous HitqualityNext Hit (e.g., sodium), and the isotopic signature of dissolved gases, Previous HitwaterNext Hit, and dissolved inorganic carbon was assessed. For the temporal variability study, Previous HitwaterNext Hit Previous HitqualityTop results from monthly sampling, as well as real-time data from a weather station and down-hole data loggers, were evaluated over an 18 month period to quantify the variability observed in measured parameters, identify relationships between parameters, and assess potential drivers of variability. Findings from these field programs improve our understanding of the inherent variability in pre- and post-drill results and offer insight into methods for improving sample collection protocols and data interpretation.