ASTM_D_4401_-_84_1995.pdf

Designation:D 4401 84(Reapproved 1995)Standard Practice forCollecting Benthic Macroinvertebrates With Petersen GrabSampler1This standard is issued under the fixed designation D 4401;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers the procedures for obtaining aqualitative sample of macroinvertebrates inhabiting sand,gravel,mud,clay,and similar substrates.1.2 This grab sampler has limited application,and is notrecommended for quantitative benthic work.1.3 The grab must be used with due consideration of itsdefects when quantitative estimates are attempted.1.4 This device is used primarily in freshwater lakes andreservoirs and is adaptable to river,estuarine,and oceanhabitats.1.5 For the advantages and disadvantages,see GuideD 4387.1.6 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 determine the applica-bility of regulatory limitations prior to use.For specifichazards,see Section 5.2.Referenced Documents2.1 ASTM Standards:D 4387 Guide for Selecting Grab Sampling Devices forCollecting Benthic Macroinvertebrates23.Summary of Practice3.1 The Petersen grab sampler has paired jaws that mustpenetrate the intended substrate without disturbing the watersurface boundary layer of the substrate,close when positionedproperly on the bottom,and retain the sample of sedimentwhile it is brought to the surface for processing.3.2 The standard Petersen grab has been modified to im-prove its efficiency and reliability.3.3 Newer versions of the Petersen grab sampler may havea screened window at the top of each jaw to allow water toescape while the grab is descending and closing.3.4 While some modifications may close or function better,the sampling characteristics remain the same.3.5 Most of the modified versions are intended for use inestuarine and marine waters.3.6 A small version can be hauled aboard by hand and heldwith one hand for washing procedures.4.Significance and Use4.1 The Petersen grab sampler is used to collect qualitativesamples from different aquatic habitats containing benthicmacroinvertebrates living on or in various types of substrates.4.2 The organisms in the sample are used to define macro-invertebrate community characteristics in water quality studiesand ecological assessments.5.Hazards5.1 The Petersen grab sampler should be inspected formechanical defects prior to use.5.2 This grab sampler cannot be used under adverse weatherconditions.5.3 It is advisable to use a winch and cable to lower andraise the sampler.5.4 Ideally a stationary boat or platform should be usedwhen taking samples.5.5 Auxiliary weights can be added to each jaw to increaseits weight for penetrating certain hard substrates.5.6 The modified Petersen devices are designed to be quiteheavy and require heavy gear and a large vessel for efficientoperation.6.Procedure6.1 The sampler is slowly lowered to the bottom when opento avoid disturbing lighter materials of the substrate.6.2 When the lowering line is slackened,a catch is released,the two scoops close,and a semicircular bite of the sediment istaken.6.3 Raise the sampler at a slow but steady rate to preventsample loss or washout.6.4 Once the grab is aboard the vessel,empty the sampleeither into a suitable container or a sieving device directly forprocessing.6.5 Thoroughly wash or hose the device with water,so thatall the sample is included in the sample processing before areplicate sample is taken.1This practice is under the jurisdiction of ASTM Committee E47 on BiologicalEffects and Environmental Fate and is the direct responsibility of SubcommitteeE47.03 on Terrestrial Assessment and Toxicology.Current edition approved Sept.28,1984.Published November 1984.2Annual Book of ASTM Standards,Vol 11.05.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard.Users of this standard are expressly advised that determination of the validity of any such patent rights,and the riskof infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of theresponsible technical committee,which you may at