Publications

Metal concentrations of the soluble fraction of the cytoplasm (cytosol) and the whole body were determined in the caddisfly Hydropsyche spp. (Trichoptera). Metal accumulation in the cytosol and the whole body were compared in samples collected along 380 kms of a contamination gradient in the Clark Fork river in four consecutive years (1992–1995), and from a contaminated tributary (Flint...

A theoretical analysis is presented that compares the response characteristics of the constant head and the constant flowrate (flow pump) laboratory techniques for quantifying the hydraulic properties of geologic materials having permeabilities less than 10-10 m/s. Rigorous analytical solutions that describe the transient distributions of hydraulic gradient within a specimen are...

The in situ measurement of water flow and chemical transport through clay pan soils is crucial to understanding potential water contamination from agricultural sources. It is important due to the large areal extent of these soils in agricultural regions of the midwestern United States and because of preferential flow paths caused by desiccation cracks, worms burrowing, and root...

Bacterial oxidation of14CH2Br2 and14CH3Br was measured in freshwater, estuarine, seawater, and hypersaline-alkaline samples. In general, bacteria from the various sites oxidized similar amounts of14CH2Br2 and comparatively less 14CH3Br. Bacterial oxidation of14CH3Br was rapid in freshwater samples compared to bacterial oxidation of 14CH3Br in more saline waters. Freshwater was also the...

Saturated hydraulic conductivity of aquifer sediments at a crude-oil spill research site near Bemidji, Minnesota were examined using pneumatically-induced head-difference tests and packer/vacuum system tests. Results from slug tests on 58 wells show that hydraulic conductivity varies both horizontally and vertically in the range from about 10-7 to 10-4 meters per second (m/s), with a...

Forty-two water analyses are reported for samples collected at 8 hot springs and their overflow drainages, two geysers, and two ambient-temperature acid streams in Yellowstone National Park during 1994-95. These water samples were collected and analyzed as part of the initial research investigations on sulfur redox speciation in the hot springs of Yellowstone and to document chemical...

A wireline-operated packer was designed for use with a standard geophysical logging system. The packer probe consists of a downhole packer inflated with water removed from the borehole by an in-line submersible pump, and a differential pressure transducer calibrated to measure the hydraulic-head difference between the zones above and below the packer. Analysis of the packer data is based...

This report is intended to summarize major findings that emerged between 1991 and 1995 from the water-quality assessment of the Willamette Basin Study Unit and to relate these findings to water-quality issues of regional and national concern. The information is primarily intended for those who are involved in water-resource management. Yet, the information contained here may also...

No abstract available.

Water samples were collected from four lakes in Byram Township, Sussex County, N.J., in the summer of 1998 as part of an investigation of the occurrence of volatile organic compounds (VOCs) in domestic wells of lakeside communities. Cranberry Lake and Lake Lackawanna are surrounded by densely populated communities where the use of gasoline-powered watercraft is prevalent, and water is...

Subsurface spills of gasoline and other petroleum products are a common environmental problem throughout the industrialized world. The U.S. Environmental Protection Agency has estimated that 40 percent of the more than 200,000 retail service stations in the United States have had accidental releases of petroleum hydrocarbons to the subsurface (U.S. Environmental Protection Agency, 1991)

Knowledge of the residence times of the ground-water systems in Chesapeake Bay watershed helps resource managers anticipate potential delays between implementation of land-management practices and any improve-ments in river and estuary water quality. This report presents preliminary estimates of ground-water residence times and apparent ages of water in the shallow aquifers of the...