Quality assurance for laboratory analysis of suspended-sediment samples by the U.S. Geological Survey in Montana

Abstract

This report describes the policies and procedures used by the Montana District sediment laboratory of the U.S. Geological Survey to assure the quality of suspended-sediment data. Suspended-sediment concentration and percentage of sediment finer than 0.062 millimeter (sand-silt separation) for stream samples are routinely analyzed by standard methods. Qualitycontrol practices and documentation are used to identify and minimize errors for the various types of equipment and procedures used for sample processing and reporting of analytical results. Data are systematically evaluated by technical review and verification prior to final approval and release of suspended-sediment data.

Water-Quality Characteristics of Cottonwood Creek, Taggart Creek, Lake Creek, and Granite Creek, Grand Teton National Park, Wyoming, 2006

“…Samples were analyzed for major-ion chemistry, nutrients, trace elements, and pesticides at the USGS National Water Quality Laboratory (NWQL) in Lakewood, Colo. Sediment samples were analyzed for suspended concentrations at the USGS sediment laboratory in Helena, Mont. (Lambing and Dodge, 1993).…”

Water-quality, bed-sediment, and biological data, for streams in the upper Prickly Pear Creek watershed, Montana, 2001

“…Water samples for suspended-sediment concentration and the percentage of suspended sediment finer than 0.062-mm diameter (silt size and smaller) were analyzed by the USGS Montana District sediment laboratory in Helena, Mont., according to gravimetric methods described by Guy (1969) and Lambing and Dodge (1993).…”

“…Standard procedures used by the NWQL for internal sample handling and quality assurance are described by Friedman and Erdmann (1982), Jones (1987), and Pritt and Raese (1995). The Montana District sediment laboratory uses quality-assurance procedures described by Lambing and Dodge (1993).…”

Surface-Water Quality-Assurance Plan for the Montana District of the U.S. Geological Survey

“…The policies and procedures related to sediment followed by the District are described in selected WRD publications and in memorandums issued by OSW, OWQ, and WRD. Techniques for sediment QA adopted by the USGS and followed by the District are presented in Knott and others (1992) and Lambing and Dodge (1993). The District also follows procedures for the collection and computation of sediment data as presented in three publications of the series "Techniques of Water-Resources Investigations of the U.S. Geological Survey" (TWRI):…”

“…In addition to using proper sampling techniques, District personnel are required to document all pertinent information necessary to accurately process samples through the District sediment laboratory. A detailed description of sediment analysis procedures and associated quality assurance used by the Montana District is presented in Lambing and Dodge (1993).…”