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Properties and chemical constituents in ground water from the middle Claiborne Aquifer, Gulf Coast regional aquifer systems, south-central United States

January 1, 1994

The U.S. Geological Survey used four programs in 1990 to provide external data quality assurance for the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Results of the intersite- comparison program indicate that 80 and 74 percent of the site operators met the NADP/NTN goals for pH determination and 98 and 95 percent of the site operators met the NADP/NTN goals for specific- conductance determination during the two studies in 1990. The effects of routine sample handling, processing, and shipping determined in the blind-audit program indicated significant positive bias for calcium, magnesium, sodium, potassium, chloride, nitrate, and sulfate. Significant negative bias was determined for hydrogen ion and specific conductance. A Kruskal-Wallis test indicated that there were no significant (a=0.01) differences in analytical results from the three laboratories participating in the interlaboratory-comparison program. Results from the collocated-sampler study indicate the median relative error for potassium and ammonium concentration and deposition exceeded 15 percent at most sites while the median relative error for sulfate and nitrate at all sites was less than 6 percent for concentration and was less than 15 percent for deposition.

Citation Information

Publication Year 1993
Title Properties and chemical constituents in ground water from the middle Claiborne Aquifer, Gulf Coast regional aquifer systems, south-central United States
DOI 10.3133/wri924104
Authors Robert A. Pettijohn, John F. Busby, Michael A. Cervantes
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Water-Resources Investigations Report
Series Number 92-4104
Index ID wri924104
Record Source USGS Publications Warehouse
USGS Organization