South Dakota Water Science Center
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Occurrence and Distribution of Semivolatile Organic Compounds in Stream Bed Sediments, United States, 1992-95Tom J. Lopes, Edward T. Furlong, and Jeffrey W. Pritt
U.S. Geological Survey, 1608 Mt. View Road, Rapid City, South Dakota 57702, USA
Phone (605) 355-4560 ext. 240, Telecopier (605) 355-4523, firstname.lastname@example.org
Streambed sediment samples were collected from 460 locations throughout the Nation and analyzed for semi-volatile organic compounds (SVOCs) to assess the occurrence and distribution of hydrophobic contaminants as part of the U.S. Geological Survey's National Water-Quality Assessment program. Samples were collected during 1992-95 near stream-flow gaging stations and from additional sites to determine concentrations of 65 SVOCs in a variety of environmental settings. At each sampling site, 5 to 10 samples were collected from depositional zones in a 100-meter reach of a stream, composited, and then sieved to less than 2 millimeters using a stainless steel sieve. Only the surficial 2 to 3 centimeters of bed sediment were sampled to characterize concentrations of SVOCs in recently deposited sediments. Forty one SVOCs were detected in more than 5 percent of the samples; 10 were detected in more than 50 percent of the samples. Of these 41 SVOCs, 27 are polycyclic aromatic hydrocarbons (PAHs), 6 are phthalates, 5 are azaarenes, 2 are phenols, and 1 is a quinone. Halogenated, nitro-, and nitroso-compounds were detected in less than 5 percent of the samples. The frequency of detection of PAHs was highest in the northeastern part of the United States and lowest in the western part. The higher frequency of detection in the northeast could be due to the larger concentration of industry and urbanization compared to other areas of the United States. Concentrations of most PAHs and bis(2-ethylhexyl) phthalate, an endocrine disruptor, significantly correlated with the amount of urban land use surrounding sample locations. Combustion of oil products and the atmosphere could be significant sources and transport mechanisms controlling the distribution of certain SVOCs.
1997, American Society of Testing and Materials, Symposium on Environmental Toxicology and Risk Assessment, 7th, St. Louis, Mo.