Low-Level VOCs Background
"Low-level" detections of CFCs and other halogenated VOCs can be quite useful in determining whether fractions of post-1940s water are present in well discharge. Here, the term "low-level" refers to concentrations that typically are below the minimum detection level (MDL) for VOCs determined by purge and trap capillary column gas chromatography with mass spectrometry (GC-MS), and can be at concentrations as low as 2 to more than 4 orders of magnitude below the commonly reported GC-MS MDL of 0.01 to 0.2 ug/L. Preliminary results of the use of low-level concentrations of CFCs and other halogenated VOCs in detecting anthropogenic inputs in drinking water were presented in Shapiro et al. (2003, 2004).
Shapiro, S. D., Busenberg, E., Plummer, L. N., and Focazio, M. J. (2003) "Data from archived chromatograms on halogenated volatile organic compounds in untreated ground water used for drinking water in the United States, 1997-2000." U.S. Geological Survey, Open-File Report, 03-352, 1-31.
Shapiro, S. D., Busenberg, E., Focazio, M. J., and Plummer, L. N. (2004) "Historical trends in occurrence and atmospheric inputs of halogenated volatile organic compounds in untreated ground water used as a source of drinking water." Sci. Total Environ., 321, 201-217.