1.1 This test method covers the determination of the dissolved gases methane, ethane, ethylene, and propane in drinking, waste, and ground waters, including domestic wells and commercial wells in the vicinity of oil and gas exploration and operations, including hydraulic fracturing, waste water injection, well closure, and reclamation. Dissolved gases in water can be analyzed up to the saturation concentration. If the water is super saturated at one atmosphere and 25C with a target dissolved gas, the sample would require dilution. This test method has an analytical range from 10 to 11 000 g/L for methane and 10 to 5000 g/L for ethane, ethylene, and propane. 1.2 This test method is applicable to samples collected at a nominal ambient pressure. Samples collected under high pressures, that is, above ambient pressure, cannot be accurately analyzed using this test method. 1.3 This test method is applicable to a variety of dissolved gases; however, for the present test method, only methane, ethane, ethylene, and propane were validated. To validate for a gas not listed in this test method, the analyst would need to establish the saturation concentration of the new gas and establish a valid curve, method detection limits, and demonstration of capability following the procedures outlined in this test method. 1.4 It is the analysts responsibility to ensure the validity of the test method for dissolved gases other than methane, ethane, ethylene, and propane and other sample matrices. 1.5 Units-The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 1.6 A single laboratory study was done to establish precision and bias for the surrogate. ASTM rules state that a test method can be approved with one laboratory with the approval of the results advisor and as long as an interlaboratory study is done within five years of the test method getting a designation. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Keywordsdissolved gas; headspace; flame ionization; ground water; drinking water; domestic well water; methane; ethane; ethylene; propane; light hydrocarbons; aqueous
Hydraulic fracturing in conjunction with horizontal drilling to tap natural gas reservoirs has sometimes caused issues with dissolved gas contamination of drinking water. Dissolved gases can be hazardous both to the environment and humans. The Robert S. Kerr EPA laboratory developed a standard operating procedure, RSK-175, to test for dissolved gases through static headspace sampling. However, as these compounds are extremely volatile, a closed sampling system is required. Furthermore, RSK-175 is a standard operating procedure and not a formal test method; thus, testing procedures for dissolved gases have had a wide range of implementations. This test method is being proposed to determine quantitatively dissolved gases in both ground and drinking water reservoirs.Back to Top