ASTM_E_1943_-_98_2015.pdf

Designation:E194398(Reapproved 2015)Standard Guide forRemediation of Ground Water by Natural Attenuation atPetroleum Release Sites1This standard is issued under the fixed designation E1943;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.1.Scope1.1 This is a guide for determining the appropriateness ofremediation by natural attenuation and implementing remedia-tion by natural attenuation at a given petroleum release site,either as a stand alone remedial action or in combination withother remedial actions.1.2 Natural attenuation is a potential remediation alternativefor containment and reduction of the mass and concentration ofpetroleum hydrocarbons in the environment to protect humanhealth and the environment.Remediation by natural attenua-tion depends upon natural processes such as biodegradation,dispersion,dilution,volatilization,hydrolysis,and sorption toattenuate petroleum constituents of concern to achieve reme-dial goals.NOTE1Remedial goals must be established through another processas determined by the appropriate regulatory agency.1.3 In general,remediation by natural attenuation shouldnot be considered a presumptive remedy.A determination ofwhether remediation by natural attenuation is appropriate foran individual petroleum release site,relative to site-specificremedial goals,requires site characterization,assessment ofpotential risks,evaluation of the need for source area control,and evaluation of potential effectiveness similar to otherremedial action technologies.Application and implementationof remediation by natural attenuation requires demonstration ofremedial progress and attainment of remedial goals by use ofconverging lines of evidence obtained through monitoring andevaluation of resulting data.When properly applied to a site,remediation by natural attenuation is a process for risk man-agement and achieving remedial goals.Monitoring should beconducted until it has been demonstrated that natural attenua-tion will continue and eventually meet remedial goals.1.3.1 The primary line of evidence for remediation bynatural attenuation is provided by observed reductions inplume geometry and observed reductions in concentrations ofthe constituents of concern at the site.1.3.2 Secondary lines of evidence for remediation by natu-ral attenuation are provided by geochemical indicators ofnaturally occurring degradation and estimates of attenuationrates.1.3.3 Additional optional lines of evidence can be providedby microbiological information and further analysis of primaryand secondary lines of evidence such as through solutetransport modeling or estimates of assimilative capacity.1.4 The emphasis in this guide is on the use of remediationby natural attenuation for petroleum hydrocarbon constituentswhere ground water is impacted.Though soil and ground waterimpacts are often linked,this guide does not address naturalattenuation in soils separate from ground water or in situationswhere soils containing constituents of concern exist without anassociated ground water impact.Even if natural attenuation isselected as the remedial action for ground water,additionalremedial action may be necessary to address other completedexposure pathways at the site.1.5 This guide does not address enhanced bioremediation orenhanced attenuation.1.6 Also,while much of what is discussed is relevant toother organic chemicals or constituents of concern,thesesituations will involve additional considerations not addressedin this guide.1.7 The guide is organized as follows:1.7.1 Section 2 lists referenced documents.1.7.2 Section 3 defines terminology used in this guide.1.7.3 Section 4 describes the significance and use of thisguide.1.7.4 Section 5 provides an overview of the use of naturalattenuation as a remedial action alternative,including;1.7.4.1 Advantages of remediation by natural attenuation asa remedial alternative;1.7.4.2 Limitations of remediation by natural attenuation asa remedial alternative;and1.7.4.3 Using multiple lines of evidence to demonstrate theappropriateness of remediation by natural remediation.1This guide is under the jurisdiction ofASTM Committee E50 on EnvironmentalAssessment,Risk Management and Corrective Action and is the direct responsibil-ity of Subcommittee E50.04 on Corrective Action.Current edition approved April 1,2015.Published July 2015.Originallyapproved in 1998.Last previous edition approved in 2010 as E194398(2010).DOI:10.1520/E1943-98R15.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 1.7.5 Section 6 describes the decision process for appropri-ate application and implementation of remediation by naturalattenuation including;1.7.5.1 Initial response,site characterization,selection ofchemicals of