Publications

No abstract available.

Identifying the sources and impacts of organic and inorganic contaminants at the watershed scale is a complex challenge because of the multitude of processes occurring in time and space. Investigation of geochemical transformations requires a systematic evaluation of hydrologic, landscape, and anthropogenic factors. The 1160 km2 Boulder Creek Watershed in the Colorado Front Range encompasses a gra

Geothermal features in the Yellowstone National Park contain up to several milligram per liter of aqueous arsenic. Part of this arsenic is volatilized and released into the atmosphere. Total volatile arsenic concentrations of 0.5–200 mg/m3 at the surface of the hot springs were found to exceed the previously assumed nanogram per cubic meter range of background concentrations by orders of magnitude

A quality management system (QMS) is a document that describes the quality policy, system, and practices of an organization. The document may include by reference other publications relating to the laboratory's arrangements.The U.S. Geological Survey QMS describes the policies, objectives, principles, organizational authority, responsibilities, accountability, and implementation plan of the Nation

No abstract available.

One of the most frequently detected organic chemicals in a nationwide study concerning the effects of wastewater on stream water quality conducted in the year 2000 was the widely used insect repellant N,N-diethyl-m-toluamide (DEET). It was detected at levels of 0.02 μg/L or greater in 73% of the stream sites sampled, with the selection of sampling sites being biased toward streams thought to be su

 The use of glyphosate has increased rapidly, and there is limited understanding of its environmental fate. The objective of this study was to document the occurrence of glyphosate and the transformation product aminomethylphosphonic acid (AMPA) in Midwestern streams and to compare their occurrence with that of more commonly measured herbicides such as acetochlor, atrazine, and metolachlor. Water

A method for the determination of 28 polycyclic aromatic hydrocarbons (PAHs) and 25 alkylated PAH homolog groups in sediment samples is described. The compounds are extracted from sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography. The compounds are identified and uantitated using capillary-column gas chromatography/mass spectrometr

A method applicable for the determination of 19 organochlorine (OC) pesticides, including total toxaphene as a complex mixture, and 3 polychlorinated biphenyl (PCB) mixtures as Aroclor equivalents--Aroclor 1016/1242, 1254, and 1260--in soil, aquatic bottom sediment, and suspended sediment is described. Method performance data are presented. The solvent system is designed to extract simultaneousl

A method for the isolation of 20 parent organophosphate pesticides and 5 organophosphate pesticide degradates from natural-water samples is described. Compounds are extracted from water samples with methylene chloride using a continuous liquid-liquid extractor for 6 hours. The solvent is evaporated using heat and a flow of nitrogen to a volume of 1 milliliter and solvent exchanged to ethyl acetate

Alkaline persulfate digestion was evaluated and validated as a more sensitive, accurate, and less toxic alternative to Kjeldahl digestion for routine determination of nitrogen and phosphorus in surface- and ground-water samples in a large-scale and geographically diverse study conducted by U.S. Geological Survey (USGS) between October 1, 2001, and September 30, 2002. Data for this study were obtai

A method for determination of the alkyl ethers u sed as gasoline oxygenates [ethyl tert-butyl ether (ETBE), methyl tert-butyl ether (MTBE), diisopropyl ether (DIPE), and tert-amyl methyl ether (TAME)], some of their main degradates [acetone, methyl acetate, tert-butyl alcohol (tBA), and tert-amyl alcohol (tAA)], and BTEX (benzene, toluene, ethylbenzene, and xylenes) at low concentrations (<5 micro