ASTM_D_6452_-_99_2012e1.pdf

Designation:D645299(Reapproved 2012)1Standard Guide forPurging Methods for Wells Used for Groundwater QualityInvestigations1This standard is issued under the fixed designation D6452;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEEditorial changes were made throughout in July 2012.1.Scope1.1 This guide covers methods for purging wells used forgroundwater quality investigations and monitoring programs.These methods could be used for other types of programs butare not addressed in this guide.1.2 This guide applies only to wells sampled at the well-head.1.3 This standard describes seven methods(A-G)for theselection of purging methods.Method AFixed VolumePurging,Method BPurging Based on Stabilization of Indi-cator Parameters,Method CPurging Based on Stabilizationof Target Analytes,Method DPurging Based on FixedVolume Combined with Indicator Parameter Stabilization,Method ELow Flow/Low Volume(Minimal Drawdown)Purging,Method FWell Evacuation Purging,and MethodGUse of Packers in Purging.1.4 This guide offers an organized collection of informationor a series of options and does not recommend a specificcourse of action.This document cannot replace education orexperience and should be used in conjunction with professionaljudgment.Not all aspects of this guide may be applicable in allcircumstances.This ASTM standard is not intended to repre-sent or replace the standard of care by which the adequacy ofa given professional service must be judged,nor should thisdocumente be applied without consideration of a projectsmany unique aspects.The word“Standard”in the title of thisguide means only that the document has been approvedthrough the ASTM consensus process.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and to determine theapplicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD4750 Test Method for Determining Subsurface LiquidLevels in a Borehole or Monitoring Well(ObservationWell)(Withdrawn 2010)3D5088 Practice for Decontamination of Field EquipmentUsed at Waste SitesD5092 Practice for Design and Installation of Ground WaterMonitoring WellsD5521 Guide for Development of Ground-Water MonitoringWells in Granular AquifersD6089 Guide for Documenting a Ground-Water SamplingEvent3.Terminology3.1 Definitions:3.1.1 For definitions of common technical terms in thisstandard,refer to Terminology D653.3.1.2 casing volumethe quantity of water contained in thecasing above the screen or open borehole.3.1.3 fixed volume purgingremoving a specified numberof well volumes to achieve purging.3.1.4 flow-through cell(purging)a vessel that allowspurge water to pass over sensors for continuous measurementof indicator parameters.3.1.5 flushingsee purging.3.1.6 grab sampling devicea bailer or similar device thatremoves an aliquot of water from the well with each insertionand removal from the well.1This guide is under the jurisdiction of ASTM CommitteeD18 on Soil and Rockand is the direct responsibility of Subcommittee D18.21 on Groundwater andVadose Zone Investigations.Current edition approved July 1,2012.Published November 2012.Originallyapproved in 1999.Last previous edition approved in 2005 as D645299(2005).DOI:10.1520/D6452-99R12E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.7 indicator parameters(purging)those physical orchemical properties,or both,used as a correlative measure todetermine when water to be sampled reflects ambient ground-water chemistry.3.1.8 low yield wella well that does not produce sufficientwater such that the objectives of purging and sampling cannotbe achieved without first removing all water from the well.3.1.9 packer(purging)an expandable device used tophysically isolate one or more zones in a well.3.1.10 purge volumethe quantity of water removed fromthe well to accomplish the objectives of purging.3.1.11 purgingthe practice of removing stagnant(stand-ing)water from a well prior to sampling.3.1.12 purging ratethe rate at which water is removedfrom a well or sampling point during purging.3.1.13 recovery rate(purging)the rate at which the waterlevel in a well returns to equilibrium with the hydraulicconditions of the formation after