South Dakota Water Science Center
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Selection Procedure and Salient Information for Volatile Organic Compounds Emphasized in the National Water-Quality Assessment ProgramDavid A. Bender, John S. Zogorski, Michael J. Halde, and Barbara L. Rowe
U.S. Geological Survey, 1608 Mountain View Road, Rapid City, South Dakota 57702
Phone (605) 355-4560 ext. 248, Telecopier, (605) 355-4523, firstname.lastname@example.org
Volatile organic compounds (VOCs) are organic compounds with chemical and physical properties that allow the compounds to move freely between water and air. Many products contain VOCs including fuels, solvents, paints, glues, adhesives, deodorizers, refrigerants, and fumigants. Because of human-health concerns, many VOCs have been the focus of national regulations, monitoring, and research during the past 10 to 20 years.
The selection procedure for VOC target analytes for emphasis in the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program, completed in 1994-96, involved three sequential phases: (1) initial selection and preliminary screening of 130 candidate compounds on the basis of available information; (2) laboratory studies to ascertain the feasibility of analysis by purge-and-trap gas chromatography/ mass spectrometry; and (3) analysis of ground-water, surface-water, and quality-control samples to ascertain the performance of laboratory methods on environmental samples. Preliminary screening considered several factors including: (1) physical properties; (2) human cancer rating; (3) noncancer human-health risk; (4) toxicity to freshwater aquatic organisms; (5) occurrence data for VOCs in ground water, surface water, and drinking water; (6) potential for atmospheric ozone depletion; (7) bioconcentration in aquatic organisms; and (8) use or potential use as a fuel oxygenate in gasoline. As a result of the selection procedure, 55 VOC target analytes were identified for additional study including 21 halogenated alkanes, 10 halogenated alkenes, 3 aromatic hydrocarbons, 9 alkyl benzenes, 6 halogenated aromatics, 4 ethers, 1 aldehyde, and 1 nitrile.
Of the 55 VOC target analytes, 29 have a national enforceable drinking-water regulation; 28 are classified as known, probable, or possible human carcinogens; 35 have noncancer human-health effects; and 33 are known to impart taste and odor to water. For the protection of freshwater biota, 33 of the 55 VOC target analytes have water-quality guidelines established by the U.S. Environmental Protection Agency, and 17 have water-quality guidelines established by Environment Canada.