Rapid mercury analysis for the field: Method development and application to natural gas utility sites

A new technique based on traditional concepts has been developed for rapid, on-site analysis of mercury in environmental media. In this method, mercury is analyzed by integration of thermal decomposition, amalgamation, and atomic absorption spectrometry (TDA-AAS). Sample preparation and analysis are essentially integrated into a single instrumental system; solid samples can be analyzed directly, without chemical pre-treatment, in an analysis time of approximately 5 minutes per sample. A wide range of standard reference material has been analyzed by TDA-AAS. Agreement with the certified values at the 95% confidence interval for all matrices tested validates this technique. Subsequent to validation, TDA-AAS has been used in a series of field studies in conjunction with remediation of mercury-contaminated soil at natural gas utility sites. Reasonable agreement has been demonstrated between TDA-AAS on-site results and laboratory results using conventional mercury analysis techniques. Independent laboratory confirmation of the field data is not required as TDA-AAS demonstrates lab-quality results on-site. This field technique has been shown to surpass traditional laboratory methods in terms of both precision and detection limits. A method for the United States Environmental Protection Agency (US EPA), Method 7473, has been developed and validated based on TDA-AAS methodology (US EPA, 1998).