The USGS National Geochemical Database: A tool for environmental and resource management

by David B. Smith

The U.S. Geological Survey (USGS) has been chemically analyzing samples of geologic material such as rocks, soils, and stream sediments since shortly after it was established in 1879. In the late 1960s, computer technology had evolved to the point where it became possible to store chemical analyses in digital databases. Over the course of the past 30 years, the analytical laboratories of the USGS's Geology Discipline have analyzed about 1.2 million samples and have preserved these analyses, along with information on the nature of the samples analyzed and their locations, in digital format. In 1985, the USGS inherited responsibility for all the data generated during the U.S. Department of Energy's (DOE) National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) Program, which was conducted from the late 1970s through the early 1980s. The NURE HSSR data represent about half a million samples of stream sediments, soils, and waters. Together, these analyses of approximately 1.7 million samples of geologic materials from USGS and DOE programs make up the USGS National Geochemical Database (NGDB). The USGS Mineral Resources Program is currently responsible for managing this important database.

For many years, two separate chemical laboratories within the USGS Geology Discipline maintained their own databases for storing chemical analyses. One of these databases was called RASS (Rock Analysis Storage System). RASS primarily contained data generated from assessments and investigations of the Nation's nonfuel mineral resources. The other database was called PLUTO (named for the god of the underworld from classical mythology). PLUTO contained data generated from many topical investigations in the Geology Discipline such as geologic mapping, volcanic hazards, energy resources, and so on. A summary of each of the three databases making up the NGDB is given below.

RASS (Rock Analysis Storage System)

• USGS data from late 1960s to late 1980s
• Data generated primarily during mineral resource assessments and investigations
• Stream sediment is dominant sample medium
• Other media include soil, rock, heavy mineral concentrates derived from stream sediment, and vegetation
• Contains data for approximately 722,000 samples (fig. 1)
• Contains about 23.6 million analytical determinations

Figure 1 - RASS sediment and soil sample locations. Vegetation sample locations not shown Compiled by J.N. Grossman, 1999. Link to larger, 79 kb, version of map.

PLUTO

• USGS data from 1970s through 1990s
• Data mostly from topical research projects other than mineral resources
• Dominantly whole-rock chemistry
• Other media include stream sediment, soil, and vegetation
• Contains data for approximately 484,000 samples (fig. 2)
• Contains about 20.5 million analytical determinations

Figure 2 - PLUTO sediment and soil samples. Vegetation sample locations not shown. Compiled by J.N. Grossman, 1998. Link to larger, 41 kb, version of map.

NURE HSSR

• Department of Energy (DOE) data from mid-1970s to early 1980s
• Data generated by four DOE national laboratories (Lawrence Livermore Laboratory, California; Los Alamos Scientific Laboratory, New Mexico; Oak Ridge Gaseous Diffusion Plant, Tennessee; and Savannah River Laboratory, South Carolina)
• Sample media are stream sediment, soil, and water
• Approximately 500,000 samples (fig. 3)

Figure 3 - NURE sediment and soil sample types. Water sample locations not shown. Compiled by J.N. Grossman, 1998. Link to larger, 61 kb, version of map.

The evolution of each database has led to inevitable inconsistencies, omissions, and, on occasion, incorrect information. The Mineral Resources Program has initiated a long-term effort to improve the quality of these databases through systematic error-identification and correction. As this effort progresses, the upgraded data are released to the public via web sites and (or) CD-ROM publications. At the moment, data are available from the following sources:

1. NURE HSSR data: http://pubs.usgs.gov/of/1997/ofr-97-0492/index.html
2. RASS data for Alaska: http://pubs.usgs.gov/of/1999/of99-433/
3. PLUTO data: USGS Digital Data Series DDS-47 (A CD-ROM publication titled National Geochemical Database: PLUTO Geochemical Database for the United States, by Phillip A. Baedecker, Jeffrey N. Grossman, and Kim P. Buttleman).

In addition to these three sources, files containing data for streams sediments, rocks, and soils from the original (pre-upgrade) RASS and PLUTO databases, as well as many other databases, can be downloaded from the following web site: http://tin.er.usgs.gov/

The geochemical data in the NGDB represent an extremely valuable tool for both resource and environmental management. Customers regularly using data from the NGDB represent Federal, State, and local environmental and public health agencies, mineral exploration companies, and companies in the private sector engaged in risk-based assessment of contaminated land. A potential user of the NGDB must recognize that the data were generated for many different purposes over the past thirty-plus years. The samples in the NGDB were collected by many different sample protocols and analyzed by many different techniques. Putting together an appropriately consistent data set from the NGDB is not a trivial effort. The contacts listed below are always happy to assist in navigating successfully through this database.

For more information

For any aspect of the National Geochemical Database, please contact:

David B. Smith
U.S. Geological Survey Denver Federal Center
Box 25046, MS 973
Denver, Colorado 80225
dsmith@usgs.gov
303-236-1849

NURE HSSR data, please contact:

Steven M. Smith
U.S. Geological Survey
Denver Federal Center
Box 25046, MS 973
Denver, Colorado 80225
smsmith@usgs.gov
303-236-1192

Geochemical data for Alaska, please contact:

Elizabeth A. Bailey
U.S. Geological Survey
4200 University Drive
Anchorage, Alaska 99508
eabailey@usgs.gov
907-786-7442