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Quality-assurance data for routine water analysis in the National Water-Quality Laboratory of the US Geological Survey for water year 1988

Water-Resources Investigations Report 89-4166

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Abstract

The US Geological Survey maintains a quality assurance program based on the analysis of reference samples for its National Water Quality Laboratory located in Denver, Colorado. Reference samples containing selected inorganic, nutrient, and precipitation (low-level concentration) constituents are prepared at the Survey 's Water Quality Services Unit in Ocala, Florida, disguised as routine samples, and sent daily or weekly, as appropriate, to the laboratory through other Survey offices. The results are stored permanently in the National Water Data Storage and Retrieval System (WATSTORE), the Survey 's database for all water data. These data are analyzed statistically for precision and bias. An overall evaluation of the inorganic major ion and trace metal constituent data for water year 1988 indicated a lack of precision in the National Water Quality Laboratory for the determination of 8 out of 58 constituents: calcium (inductively coupled plasma emission spectrometry), fluoride, iron (atomic absorption spectrometry), iron (total recoverable), magnesium (atomic absorption spectrometry), manganese (total recoverable), potassium, and sodium (inductively coupled plasma emission spectrometry). The results for 31 constituents had positive or negative bias during water year 1988. A lack of precision was indicated in the determination of three of the six nutrient constituents: nitrate plus nitrite nitrogen as nitrogen, nitrite nitrogen as nitrogen, and orthophosphate as phosphorus. A biased condition was indicated in the determination of ammonia nitrogen as nitrogen, ammonia plus organic nitrogen as nitrogen, and nitrate plus nitrite nitrogen as nitrogen. There was acceptable precision in the determination of all 10 constituents contained in precipitation samples. Results for ammonia nitrogen as nitrogen, sodium, and fluoride indicated a biased condition. (Author 's abstract)

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Quality-assurance data for routine water analysis in the National Water-Quality Laboratory of the US Geological Survey for water year 1988
Series title:
Water-Resources Investigations Report
Series number:
89-4166
Edition:
-
Year Published:
1989
Language:
ENGLISH
Publisher:
Dept. of the Interior, U.S. Geological Survey : Books and Open-File Reports [distributor],
Description:
x, 96 p. :ill. ;28 cm.