Designation:D4401–84(Reapproved2002)StandardPracticeforCollectingBenthicMacroinvertebratesWithPetersenGrabSampler1ThisstandardisissuedunderthefixeddesignationD4401;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticecoverstheproceduresforobtainingaqualitativesampleofmacroinvertebratesinhabitingsand,gravel,mud,clay,andsimilarsubstrates.1.2Thisgrabsamplerhaslimitedapplication,andisnotrecommendedforquantitativebenthicwork.1.3Thegrabmustbeusedwithdueconsiderationofitsdefectswhenquantitativeestimatesareattempted.1.4Thisdeviceisusedprimarilyinfreshwaterlakesandreservoirsandisadaptabletoriver,estuarine,andoceanhabitats.1.5Fortheadvantagesanddisadvantages,seeGuideD4387.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.Forspecifichazards,seeSection5.2.ReferencedDocuments2.1ASTMStandards:D4387GuideforSelectingGrabSamplingDevicesforCollectingBenthicMacroinvertebrates23.SummaryofPractice3.1ThePetersengrabsamplerhaspairedjawsthatmustpenetratetheintendedsubstratewithoutdisturbingthewatersurfaceboundarylayerofthesubstrate,closewhenpositionedproperlyonthebottom,andretainthesampleofsedimentwhileitisbroughttothesurfaceforprocessing.3.2ThestandardPetersengrabhasbeenmodifiedtoim-proveitsefficiencyandreliability.3.3NewerversionsofthePetersengrabsamplermayhaveascreenedwindowatthetopofeachjawtoallowwatertoescapewhilethegrabisdescendingandclosing.3.4Whilesomemodificationsmaycloseorfunctionbetter,thesamplingcharacteristicsremainthesame.3.5Mostofthemodifiedversionsareintendedforuseinestuarineandmarinewaters.3.6Asmallversioncanbehauledaboardbyhandandheldwithonehandforwashingproc...
