Laboratory Sub-Sampling and Analysis for Methane in Water
Oral Presentation
Prepared by J. Black, M. McGarvey, T. Upadhyay, P. Higgins
PA Department of Environmental Protection - Bureau of Laboratories, PO Box 1467, Harrisburg, PA, 17105, United States
Contact Information: [email protected]; 717-346-8638
ABSTRACT
Analysis of methane and other light hydrocarbon gases in water has been of increasing interest in recent years due to the increase in shale gas drilling. Migration of methane from drilling sites into nearby residential wells is a public concern with regards to the health and safety of US citizens. However, because methane is not regulated in water by the EPA, there are no published methods available to guide the analysis techniques used by commercial and governmental laboratories. The EPA SOP known as RSK175 has been in use for many years along with several variations including purge & trap analysis and the use of aqueous calibration standards instead of the gaseous standards. In addition, an ASTM method is currently being reviewed for possible publication.
One of the stipulations of RSK175 and the upcoming ASTM method is that the sample vial must not be opened prior to analysis of the sample. The recommended technique of using compressed helium to force sample from the vial into a syringe for analysis is time consuming and inefficient in a production laboratory setting. A study conducted in our laboratory addresses the question: Does opening of the vial prior to analysis significantly affect the data obtained for the sample? The results show that along with the use of good laboratory technique, the effect of opening the vial prior to analysis may not be as significant as previously assumed. In addition, a review of the three primary analytical techniques used for methane analysis will be presented.
Oral Presentation
Prepared by J. Black, M. McGarvey, T. Upadhyay, P. Higgins
PA Department of Environmental Protection - Bureau of Laboratories, PO Box 1467, Harrisburg, PA, 17105, United States
Contact Information: [email protected]; 717-346-8638
ABSTRACT
Analysis of methane and other light hydrocarbon gases in water has been of increasing interest in recent years due to the increase in shale gas drilling. Migration of methane from drilling sites into nearby residential wells is a public concern with regards to the health and safety of US citizens. However, because methane is not regulated in water by the EPA, there are no published methods available to guide the analysis techniques used by commercial and governmental laboratories. The EPA SOP known as RSK175 has been in use for many years along with several variations including purge & trap analysis and the use of aqueous calibration standards instead of the gaseous standards. In addition, an ASTM method is currently being reviewed for possible publication.
One of the stipulations of RSK175 and the upcoming ASTM method is that the sample vial must not be opened prior to analysis of the sample. The recommended technique of using compressed helium to force sample from the vial into a syringe for analysis is time consuming and inefficient in a production laboratory setting. A study conducted in our laboratory addresses the question: Does opening of the vial prior to analysis significantly affect the data obtained for the sample? The results show that along with the use of good laboratory technique, the effect of opening the vial prior to analysis may not be as significant as previously assumed. In addition, a review of the three primary analytical techniques used for methane analysis will be presented.
