Publications

Organic explosives are determined in samples of ground water and surface water with emphasis on identifying and quantifying trinitrotoluene (TNT) metabolites. Water samples are filtered to remove suspended particulate material and passed through a polystyrene divinylbenzene-packed cartridge by a vacuum-extraction system. The target analytes subsequently are eluted with acetonitrile. A...

The analysis of natural-water samples for antimony by automated-hydride atomic absorption spectrophotometry is described. Samples are prepared for analysis by addition of potassium and hydrochloric acid followed by an autoclave digestion. After the digestion, potassium iodide and sodium borohydride are added automatically. Antimony hydride (stibine) gas is generated, then swept into a...

Twenty-two bottom-sediment samples were collected from Town Lake in Austin, Texas, in 1991 and 1992 and analyzed for chlorinated insecticides by a reconnaissance-quality, electron-capture gas chromatography screening method developed by the U.S. Geological Survey (USGS). Four different chlorinated insecticides (aldrin, chlordane, dieldrin, and p,p'-DDT) and two degradation products of p...

This Services Catalog contains information about field supplies and analytical services available from the National Water Quality Laboratory in Denver, Colo., and field supplies available from the Quality Water Service Unit in Ocala, Fla., to members of the U.S. Geological Survey's Water Resources Division. To assist personnel in the selection of analytical services, this catalog lists...

All inorganic and organic methods for analyzing samples of water and fluvial sediment, which have been approved for use by the U.S. Geological Survey from 1954 to the present (1994), are listed. Descriptive method names include references to published reports for easy retrieval of methodology. The year each method was approved is listed as well as the year the method was discontinued...

As part of its primary responsibility concerning water as a national resource, the U.S. Geological Survey collects and analyzes samples of ground water and surface water to determine water quality. This report describes the method used since June 1987 to determine selected total-recoverable carbamate pesticides present in water samples. High- performance liquid chromatography is used to...

No abstract available.

The National Water Quality Laboratory determines organic and inorganic constituents in samples of surface and ground water, river and lake sediment, aquatic plant and animal material, and precipitation collected throughout the United States and its territories by the U.S. Geological Survey. In water year 1994, the Laboratory produced more than 900,000 analytical results for about 65,000...

On March 15, 1979, four moderate earthquakes (ML 4.9, 5.3, 4.5, 4.8) occurred in the Homestead Valley area of the Mojave Desert (Figure 1). At that time, they were noteworthy for a vigorous aftershock sequence and for off-fault epicentral locations that formed a cruciform pattern (Hutton, et al., 1980; Stein and Lisowski, 1983). More recently, there is renewed interest in the Homestead...

No abstract available.

Water and streambed-sediment samples were collected on March 9 and 10,1987 from one site upstream and three sites downstream of the discharge from a municipal wastewater-treatment plant on Rowlett Creek near Dallas, Texas. To extract and separate organic compounds, purgeand-trap, closed-loop stripping, and pH-adjusted solvent extraction methods were used for water samples; and a Soxhlet...

Increased awareness of the quality of water in the United States has led to the development of a method for determining low levels (0.2-5.0 microg/L) of silver in water samples. Use of graphite furnace atomic absorption spectrophotometry provides a sensitive, precise, and accurate method for determining low-level silver in samples of low ionic-strength water, precipitation water, and...