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Microbiological and Chemical Exposure Assessment

Research In Action

Development of analytical methods for measuring contaminants in drinking water


There is potential for residues of unregulated contaminants to be present in drinking water, however little is known about their prevalence in the environment. To protect public health, EPA needs information about how common it is for various contaminants to be present in drinking water. Sometimes there is no analytical method available to detect a particular contaminant. In these situations, new analytical methods must be developed.


EPA scientists have developed a number of new methods for the detection of unregulated contaminants. EPA Method 522 uses gas chromatography and mass spectrometry, to detect and quantify the presence of 1,4-dioxane — a chemical that can irritate the eyes and digestive tract, and may also be a human carcinogen. EPA Method 537 uses liquid chromatography and mass spectrometry together to test water for perfluorinated alkyl acids, which may be carcinogenic to humans. EPA Method 538 can be used to detect and quantify pesticides or pesticide degradates using direct aqueous injection liquid chromatography and mass spectrometry.

Result and Impact

These methods are under consideration by EPA for use in a future EPA national drinking water study. These national studies are conducted every five years to test public water systems for selected unregulated contaminants. The data from these studies helps inform policies that keep drinking water safe and clean. Under the Safe Drinking Water Act, EPA regularly monitors water contaminants that have the potential to pose a threat to human health.

For more information on EPA analytical methods developed to detect unregulated contaminants in drinking water, see www.epa.gov/nerlcwww/ordmeth.htm

Related Publications
  • Grimmett, P.E. and J.W. Munch, Method Development for the Analysis of 1,4-Dioxane in Drinking Water Using Solid Phase Extraction and Gas Chromatography/Mass Spectrometry, Journal of Chromatographic Science, 47: 31-39 (2009).
  • Shoemaker, J.A., B. Boutin, P. Grimmett, Development of a U.S. EPA Drinking Water Method for the Analysis of Selected Perfluoroalkyl Compounds by Solid-Phase Extraction and LC/MS/MS, Journal of Chromatographic Science, (2009), 47(1), 3-11.
  • Shoemaker, J.A., Development and multi-laboratory verification of U.S. EPA Method 538 for the Analysis of Drinking Water Contaminants by Direct Aqueous Injection-LC/MS/MS, Analytical Methods, 3, 1628- 1636 (2011)

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