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Purging A quantity of water is purged to remove stagnant water and draw in water <br />representative of the aquifer prior to sampling. In "micropurge" systems such as <br />pneumatic pump setups, the pump is set in the open interval and just enough water is <br />purged to clear the delivery tubing and pump chamber, counting on ground water flowing <br />through the wellbore to keep the open interval flushed. Where pumps are not set in the <br />open interval, it is necessary to waste a certain volume ("macropurge") to clear stagnant <br />water in the casing. There is a common convention specifying three wellbore volumes <br />should be purged for an adequate purge; but this convention is not strictly applicable to <br />deep wells with complex water bearing intervals. <br />Pyrolysis Shell's in situ heating leads to melting of kerogen, and cracking of its long chain <br />hydrocarbons to short chain and aromatic compounds, over an extended period <br />QA (quality assurance) samples Blanks, duplicates and spikes submitted for analysis to <br />confirm acceptable analytical quality. Analytical QA is distinct from data QA. QA samples <br />include: <br />Trip blanks are bottles filled with de-ionized water by the laboratory that ship to <br />the site with empties, and returned to the lab without opening <br />Field blanks are filled at a well location with de-ionized water <br />Rinse blanks are filled by running de-ionized water through the wellhead <br />connection and sampling fittings <br />Duplicates are collected with an "original" sample, interspersing them so that <br />filling of the original metals bottle is followed by the duplicate metals <br />bottle, original VOA by duplicate VOA, etc. <br />Spike samples are made up by dilution of a standard solution of a number of <br />constituents with de-ionized water <br />Well bore volume Purging volumes are usually referenced to a well bore volume. This is the <br />quantity of water standing in the wellbore, including cased and open intervals. It is thus <br />the length from water level to total depth times the appropriate cross sectional areas. Not <br />all of the standing water column in the well is expelled by purging, since the column <br />above the pump is only fractionally drawn down. The volume of the column between the <br />pump and the open interval (the conduit volume) is a bare minimum purge volume. <br />EAST RDD ENVIRONMENTAL MONITORING, SAMPLING AND ANALYSIS PLAN <br />TOC-4