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How frequently are volatile organic compounds (VOCs) detected in groundwater?

Volatile organic compounds (VOCs), which are widely used in the manufacture of many products including refrigerants, plastics, adhesives, paints, and petroleum products, have been detected in about one-third of the wells sampled by the National Water-Quality Assessment (NAWQA) Program of the USGS. 

  • Chloroform and other trihalomethanes, the most commonly detected compounds, were found in about 9 percent of the sampled wells.
  • Solvents, particularly chlorinated solvents, were found in about 8 percent of sampled wells.

VOCs predominantly occur in urban areas, often in mixtures; specifically, 2 or more compounds were found in about one quarter of the sampled urban wells.

Learn More: Volatile Organic Compounds in the Nation’s Ground Water and Drinking-Water Supply Wells