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Emerging and Recalcitrant Compounds in Groundwater

Water Quality Control

  1. Tom Mohr1,
  2. James A. Jacobs2

Published Online: 15 APR 2005

DOI: 10.1002/047147844X.wq609

Water Encyclopedia

Water Encyclopedia

How to Cite

Mohr, T. and Jacobs, J. A. 2005. Emerging and Recalcitrant Compounds in Groundwater. Water Encyclopedia. 2:316–319.

Author Information

  1. 1

    Santa Clara Valley Water District, San Jose, California

  2. 2

    Environmental Bio-Systems, Inc., Mill Valley, California

Publication History

  1. Published Online: 15 APR 2005


During the last two decades, the dominant groundwater contamination issues have focused on petroleum hydrocarbons (including gasoline, diesel, motor oil, lubricants, and jet fuel), chlorinated solvents, metals, and pesticides. Recently, attention has shifted to a variety of newly discovered compounds in groundwater. Some of these compounds were additives to fortify or stabilize the previously mentioned products. As additives, these compounds were present at low ratios, ranging from 10% to less than 1% of the total volume of the product. Though widely used in industry for decades, these emerging compounds were, until recently, not analyzed or regulated. Emerging and recalcitrant compounds include, but are not limited to, methyl tertiary-butyl ether (MtBE) a gasoline oxygenate additive; perchlorate, the major component of solid rocket motors and a minor ingredient of highway safety flares, and various stabilizers of chlorinated solvents such as 1,4-dioxane. Many of these recalcitrant compounds are also suspected to be carcinogenic or to cause other adverse health effects. Consequently, advisory drinking water action levels have been adopted for many emerging contaminants; regulatory agencies have added these compounds to their list of Compounds of Interest at remediation sites.


  • 1,4-dioxane;
  • abiotic degradation;
  • biotransformation;
  • emerging contaminants;
  • fuel oxygenate;
  • MtBE;
  • recalcitrant compound;
  • solvent stabilizers