U.S. Geological Survey External Quality-Assurance Project Report for the National Atmospheric Deposition Program / National Trends Network and Mercury Deposition Network, 2011-12

Wetherbee, Gregory A.; Martin, RoseAnn

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https://hdl.handle.net/2142/88412 Copy

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Title

U.S. Geological Survey External Quality-Assurance Project Report for the National Atmospheric Deposition Program / National Trends Network and Mercury Deposition Network, 2011-12

Author(s)

• Wetherbee, Gregory A.
• Martin, RoseAnn

Issue Date

2014-07

Keyword(s)

• National Atmospheric Deposition Program and National Trends Network (U.S.)
• Mercury Deposition Network (U.S.)
• Mercury
• Chemical analysis
• Rain gauges
• Precipitation

Abstract

The U.S. Geological Survey operated six distinct programs to provide external quality-assurance monitoring for the National Atmospheric Deposition Program (NADP) / National Trends Network (NTN) and Mercury Deposition Network (MDN) during 2011–2012. The field-audit program assessed the effects of onsite exposure, sample handling, and shipping on the chemistry of NTN samples; a system-blank program assessed the same effects for MDN. Two interlaboratory-comparison programs assessed the bias and variability of the chemical analysis data from the Central Analytical Laboratory and Mercury Analytical Laboratory (HAL). A blind-audit program was implemented for the MDN during 2011 to evaluate analytical bias in HAL total mercury concentration data. The co-located–sampler program was used to identify and quantify potential shifts in NADP data resulting from the replacement of original network instrumentation with new electronic recording rain gages and precipitation collectors that use optical precipitation sensors. The results indicate that NADP data continue to be of sufficient quality for the analysis of spatial distributions and time trends of chemical constituents in wet deposition across the United States. Co-located rain gage results indicate -3.7 to +6.5 percent bias in NADP precipitation-depth measurements. Co-located collector results suggest that the retrofit of the NADP networks with the new precipitation collectors could cause +10 to +36 percent shifts in NADP annual deposition values for ammonium, nitrate, and sulfate; -7.5 to +41 percent shifts for hydrogen-ion deposition; and larger shifts (-51 to +52 percent) for calcium, magnesium, sodium, potassium, and chloride. The prototype N-CON Systems bucket collector typically catches more precipitation than the NADP-approved Aerochem Metrics Model 301 collector.

Publisher

Illinois State Water Survey

Series/Report Name or Number

ISWS Miscellaneous Publication MP-202

Type of Resource

text

Language

en

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http://hdl.handle.net/2142/88412

Sponsor(s)/Grant Number(s)

National Atmospheric Deposition Program

Copyright and License Information

Copyright ... University of Illinois Board of Trustees. All rights reserved. This document is a product of the Illinois State Water Survey, and has been selected and made available by the Illinois State Water Survey and the University Library, University of Illinois at Urbana-Champaign. It is intended for research and educational use, and proper attribution is requested.

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