Using genetic analysis of organic material found in aquatic environments it is possible to detect the presence of organisms without necessarily observing or capturing individuals. Explains terms, methods, and prospective utility of this approach.
Using ground-water geochemical analyses, and mathematical models, the factors affecting the quality of public water supply were identified as pumping schedule, screened interval, past land use within the recharge area, and natural geochemical conditions.
Using ground-water geochemical analyses and mathematical models, the factors affecting the quality of public water supply were identified as mixing of very recent recharge with older water, karst features, natural geochemical processes, and pumping.
Well vulnerability results from the young age of groundwater. Karst features permit contaminants to move into the aquifer easily, leading to a well mixed aquifer; geochemical processes do not degrade contaminants quickly.
Maps and text (Word or PDF format) and database (Excel or HTML format) for bedrock, forest floor, and mineral soil sampling in Voyageurs National Park, Minnesota to establish the background and baseline geochemistry and terrestrial mercury sources.
Homepage for the Biochemistry and Physiology Branch in Columbia, MO, which develops analytical techniques (cell bioassay/immunoassay) on toxicity related to fish and wildlife; and conducts research in microbiology and physiology.
Shows how coral reef specimens are collected, the type of information gained from them, and the methods by which they are measured and studied to understand recent (past few centuries) changes in climate.
Report describing the results of an interdisciplinary environmental study of the World Trade Center (WTC) area after the attack on September 11, 2001. The investigations included imaging spectroscopy mapping and laboratory analysis.
Direct measurement of an important indicator of interannual variability is extended, using geological proxy measures, farther back in time to well before modern measurements were made. This tells us about the history of climate variability.
Highlights research studies involving genetics and genomics, includes a glossary of terms on the subject, a directory of scientists involved in this type of work, and description of research facilities through which USGS carries out genetic studies
Describes the value of molecular biology genetic tools in enhancing the delineation of the genetic diversity and the effects of environmental degradation on living species. Links to research, which differentiated two species of sage-grouse.
Site to obtain currently available geochemical reference materials, certificates for reference materials no longer available, reference materials in production, and order and processing information. Some documents in PDF format.
Manual of chemical sediment analysis using Coulometer and CHN Analyzers to measure carbon content, spectrometric analysis for biogenic silica, and radiochemistry to measure isotopes. Includes techniques,sample preparation, and safety procedures.
Overview of chemical analyses, tracer studies, gas geochemistry, stable isotopes analyses, organic chemistry, and thermometry capabilities at major USGS laboratories with links to technique, equipment, and contacts for each procedure.
Services available at the Geological Survey TRIGA Reactor (GSTR) site in Denver with information on irradiation, neutron activation analysis, fission track radiography, and geochronology and tours of the facility.
The occurrence of solvents in the groundwater is not correlated with current overlying land use and human activities. Rather, the solvents are from legacy industrial uses, and it has taken decades for the groundwater to move to where it is now pumped.
Vanadium and boron were detected at high and moderate concentrations in this area. High concentrations for these constituents were detected almost exclusively in samples collected in the Temecula Valley study area.
Report presents an abridged guide for laboratory technicians and students using X-ray powder diffraction methodology to study crystalline structure and to determine the mineralogy of finer grained sediments, especially clays.
Homepage for the Missouri District Water-Quality Data & Analysis Section with links to data networks, projects, data availability, mobile laboratories, sampling boat, quality assurance practices, and real-time water-quality data.
Description of project monitoring the status of Greater Glacier National Park Area's grizzly bear and black bear populations using genetic techniques on DNA from bear hair or scats without handling bears, with photos and discussion of methods.
This report presents geochemical data generated during mineral and environmental assessments for the Bureau of Land Management in northern Nevada, northeastern California, southeastern Oregon, and southwestern Idaho, along with metadata and maps.
Homepage for description of the National Stream Quality Network (NASQAN), a long-term program monitoring the concentrations and flux of sediment and chemicals in the Nation's largest rivers (Mississippi, Columbia, Colorado, Rio Grande, and Yukon).
Project to assess the grizzly bear population size, trend, and survival in the Northern Continental Divide Ecosystem (NCDE) in Montana to improve the long-term survival for this threatened species. With description, DNA identification means and photos.
Results (*.pdf) of a 1998 targeted reconnaissance survey on the sources of radium, polonium, and lead radionuclides, data collection and laboratory methods, existing occurrences in drinking water, risk assessments, and compliance monitoring.
In all, 56 compounds were detected in samples collected approximately monthly during 2003-05 at the intake for the Clackamas River Water plant. On the basis of this screening-level assessment, adverse effects to human health are assumed to be negligible.
Description of the Denver Organic Geochemistry Laboratory where chemical and geological data is used to research the physical and chemical processes of hydrocarbon generation, migration and accumulation, with links to programs, personnel, and products.
The Organic Geochemistry Research Group of the Kansas District focuses on the fate and transport of organic contaminants in the environment with links to objectives, analytical methods, laboratory methods, publications, events, photos, and personnel.
We identified six compounds at concentrations less than human-health benchmarks, but within a factor of 10 of those limits. Those compounds might warrant further study to understand their transport and fate within the watershed.
Measured concentrations of many compounds in water people use. Some compounds are regulated as health hazards; a few of these were over the benchmark limits. Others may become issues of concern, so studies such as this give us helpful background levels.
Report of completed reservoir sediment studies in Kansas using a combination of bathymetric surveying, sediment coring, chemical analysis, and statistical analysis to understand the quantity and quality of deposited sediment.
Site on the Chlorofluorocarbon Laboratory and its analytical services for CFCs, sulfur hexafluoride, dissolved gases including nitrogen, argon, methane, carbon dioxide, oxygen, and helium, and tritium/helium-3 dating.
Links to Spectroscopy Lab projects to identify and map materials through spectroscopic remote sensing (imaging spectroscopy, hyperspectral imaging, imaging spectrometry, ultraspectral imaging, etc) on the Earth and in space.
Instrument measures elemental abundance and isotopic ratios in samples as small as a few nanograms. Uses include geochronology, geological thermometry, and trace element geochemistry of geological and biological materials.
USGS operates a low-enriched uranium-fueled, pool-type reactor located at the Denver Federal Center. We use it for analyses of fissile and fissionable isotopes, geochemical analysis, and geochronology.
Iron ore containing elevated concentrations of trace metals was smelted here during 113 years of operation (1771-1883). We sampled a variety of materials nearby to determine the amount of metals such as arsenic, chromium, copper, lead, and zinc.
Site with a series of articles showing how chemists and geologists use analytical chemistry to determine the age of the Earth, determine Earth's history, predict volcanic eruptions, observe long-term atmospheric change and study pollution.
Contaminants from mines move more easily from ore materials and mine waste piles to surrounding estuaries and living organisms when water moves through the mine site. Geochemical results shown here will help people mitigate the negative effects.