Testing under Phase III of the Marcellus Shale Coalition (MSC) Dissolved Methane investigation was initiated in early January, 2018. This study is a continuation of the round-robin dissolved methane evaluation conducted by the MSC during 2014-2015 (Phase I) and 2016 (Phase II). Recommendations from the earlier phases included the need for a study to work with the laboratories with significant deviation from phases and ultimately also the development of a commercially available reference standard. The earlier phases identified calibration and differences between sample and standard handling as the primary source of bias. For this Phase III study, synthetic methane reference standards were prepared by Environmental Service Laboratories (ESL; Indiana, Pennsylvania). The samples were then labeled and shipped to each of the participating laboratories for methane analysis. Three reference laboratories and eight non-reference laboratories were included in the study. The non-reference laboratories were chosen from the prior phases as those laboratories with significant bias from the accepted value. These laboratories were instructed to carefully self-diagnose their procedures, use the prepared and known concentration standards, and identify the procedures, activities, and/or techniques that are causing the bias.
A Phase III report has recently been drafted. The draft describes the steps taken to prepare the reference standards, and the metrics used to verify the usability of those standards. The draft report also describes the laboratory procedures influencing the variability observed with dissolved methane concentrations. Further, the report will highlight laboratory best practices for the analysis of dissolved light gases from domestic water well samples to support a publishable analytical method.