Dissolved Light Gas Validation Studies Presented to the SW-846 Organic Methods Workgroup

In October 2022, David Gratson, CEAC, and Rock Vitale, CEAC, of Environmental Standards presented a summary of a series of light gas studies, collected over the 7 years of work, to the US EPA SW-846 Organic Methods Workgroup. From the beginning in 2015, their goal had been to validate and then publish with agency approval/endorsement, a method that the environmental community will follow. Prior data had clearly illustrated poor precision and inaccuracy when measuring these compounds. Through this work commissioned by the Marcellus Shale Coalition, they have put forward an excellent solution. 

Vitale and Gratson conducted the multi-year collaborative study involving laboratory, government, and consulting entities. They designed all phases of the study, including the final multi-laboratory study that included eight participating laboratories (including one state and one US EPA laboratory). The sponsors and stakeholders undertook this effort to ensure that a multi-laboratory validated method for potable groundwater sources, with known accuracy and precision, would be available to the laboratory community to appropriately protect public health.

The study was performed over a 7-year period and documented major laboratory performance issues, diagnosed/remediated those issues, and standardized a multi-laboratory validated method for the analysis for dissolved light gases.

During the initial study phases, significant precision and accuracy problems were observed; variability and low bias were identified within an alarming number of participating laboratories. Additional information collected and shared during the subsequent phases of the study resulted in notable improvements in precision and accuracy across all participating laboratories.

The lessons learned with 26 participating laboratories were applied in the preparation of the light gas analytical method used in the two rigorous inter-laboratory studies using real-world, spiked groundwater and a commercially available light gas certified reference material.