Precipitation Chemistry Quality Assurance Project (PCQA)

National Atmospheric Deposition Program

INSTRUCTIONS FOR SUBMISSION OF THE SYSTEM BLANK SAMPLE

These instructions are available as a PDF file

PLEASE READ ALL INSTRUCTIONS CAREFULLY BEFORE PROCEEDING

Your site has been selected to participate in the system blank program, one of the external quality-assurance programs operated by the U.S. Geological Survey for the National Atmospheric Deposition Program/Mercury Deposition Network (NADP/MDN). The system blank program is designed to measure the effects of field exposure, handling and processing on the chemistry of NADP/MDN precipitation samples. This program is vital in maintaining high data quality produced by the NADP.

Please do not submit a system blank sample until a week without precipitation occurs at your site


The sample you have been sent should be submitted after the first standard Tuesday-to-Tuesday sampling week without precipitation within the next 12 months. Tthe last day of sample submission is stated on the sample bottle you received. If this time period passes without a full dry week, please ship the sample to Frontier Global Sciences, Inc. either in the original box in which it was sent or in an open slot in the MDN cooler. Mail the enclosed post card to the U.S. Geological Survey explaining that there were no dry weeks prior to the deadline date.

ENCLOSED PLEASE FIND THE FOLLOWING SUPPLIES:
  1. One - system blank sample
  2. Two - MDN Observer Forms for the system sample and bottle sample
  3. One - postage paid post card addressed to the U.S. Geological Survey for recording the site id and date the system blank sample is shipped to Frontier Geosciences Inc.


If you did not receive any of these items or these instructions are unclear, please call Greg Wetherbee at (303)236-1837.

OTHER SUPPLIES YOU WILL NEED (ITEMS PROVIDED BY FRONTIER GLOBAL SCIENCES, INC. THAT YOU NORMALLY USE TO PROCESS WEEKLY PRECIPITATION SAMPLES):
  1. A standard cooler for shipping samples to Frontier Global Ssciences, Inc.


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OVERVIEW: The system blank sample must be processed on a Tuesday, when you visit your MDN site. If no precipitation occurred during the preceding week, 50% of the system blank sample will be poured through the precipitation collection funnel of the MDN collector into the "sample collection bottle" that spent the previous week installed in the collector. After the transfer, the "sample collection bottle" will be handled in the same manner as an actual precipitation sample and sent to Frontier Geosciences Inc. The remaining 50% of the system blank sample will be shipped to Frontier Global Xciences Inc. in its original bottle. There are many detailed steps that need to be correctly completed, so please read all of the instructions carefully and follow them in the order listed.
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INSTRUCTIONS
  1. Verify that no precipitation occurred during the preceding week
    Process and submit a system blank sample only if you have a standard Tuesday-to-Tuesday period when no precipitation occurred. Check the rain gage chart, making sure the collector lid did not open and uncover the sample train. Any event pen marks indicating that the sensor was activated must not have been accompanied by even the slightest rise on the precipitation record pen trace. If you are in an area with high humidity that results in lid openings during the week without precipitation, please note this in the comments section of the observer form (example: "collector opened due to heavy fog/humidity, but no precipitation occurred"). The precipitation trace must be absolutely flat even if there were lid openings in response to periods of high humidity. Verify the record is complete and there were no clock stoppages or pen skips on the event recorder chart. If equipment malfunctioned during the preceding week, please do not process the system blank sample. Once you have verified that: 1) the wet deposition collector was working properly during the week; and 2) there was no precipitation. Lid openings not caused by precipitation are acceptable. Proceed to step B to begin processing the system blank sample.


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