ASTM_E_1242_-_97_2014.pdf

Designation:E124297(Reapproved 2014)Standard Practice forUsing Octanol-Water Partition Coefficient to EstimateMedian Lethal Concentrations for Fish Due to Narcosis1This standard is issued under the fixed designation E1242;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 practice covers a procedure for estimating thefathead minnow(Pimephales promelas)96-h LC50 of nonre-active(that is,covalently bonded without unsaturated residues)and nonelectrolytic(that is,require vigorous reagents tofacilitate substitution,addition,replacement reactions and arenon-ionic,non-dissociating in aqueous solutions)organicchemicals acting solely by narcosis,also referred to as Meyer-Overton toxicity relationship.21.2 This procedure is accurate for organic chemicals that aretoxic due to narcosis and are non-reactive and non-electrolytic.Examples of appropriate chemicals are:alcohols,ketones,ethers,simple halogenated aliphatics,aromatics,and aliphaticsubstituted aromatics.It is not appropriate for chemicals whosestructures include a potential toxiphore(that structural compo-nent of a chemical molecule that has been identified to showmammalian toxicity,for example CN is known to be reponsiblefor inactivation of enzymes,NO2for decoupling of oxidativephosphorylation,both leading to mammalian toxicity).Ex-amplesofinappropriatechemicalsare:carbamates,organophosphates,phenols,beta-gamma unsaturated alcohols,electrophiles,and quaternary ammonium salts.2.Referenced Documents2.1 ASTM Standards:3E729 Guide for Conducting Acute Toxicity Tests on TestMaterials with Fishes,Macroinvertebrates,and Amphib-iansE943 Terminology Relating to Biological Effects and Envi-ronmental FateE1023 Guide for Assessing the Hazard of a Material toAquatic Organisms and Their UsesE1147 Test Method for Partition Coefficient(N-Octanol/Water)Estimation by Liquid Chromatography(With-drawn 2013)43.Terminology3.1 Definitions:3.1.1 narcosisareversiblestateofstupor,unconsciousness,or arrested activity produced by the influenceof chemicals on critical sites within membranes or by disrupt-ing the normal functioning of certain proteins by means ofnonspecific binding of organic chemical(s)to hydrophobicsites.Death results if exposure is not terminated after a lengthof time which varies with concentration.3.1.2 octanol-water partition coeffcient(Kow)referred toas P in some literature.3.1.3 toxiphorea chemical structure substituent group thatwhen present gives rise to an adverse effect in exposedorganisms.3.2 For definitions of other terms used in this standard,referto Guide E729,Terminology E943,and Guide E1023.4.Summary of Practice4.1 The hydrophobicity of a non-reactive and non-electrolytic organic chemical as quantified by log of theoctanol-water partition coefficient is substituted into an experi-mentally derived equation and an approximate 96-h log LC50for fathead minnow is calculated.This value is a maximumvalue.The actual LC50 could be lower,but should not behigher.5.Significance and Use5.1 This procedure can be used to limit the need forscreening tests prior to performing a test for estimating theLC50 of a non-reactive and non-electrolytic chemical to thefathead minnow.By eliminating the screening test,fewer fishneed be tested.The time used for preparing and performing the1This practice is under the jurisdiction of ASTM Committee E50 on Environ-mental Assessment,Risk Management and Corrective Action and is the directresponsibility of Subcommittee E50.47 on Biological Effects and EnvironmentalFate.Current edition approved Oct.1,2014.Published December 2014.Originallyapproved in 1988.Last previous edition approved in 2008 as E1242 97(2008).DOI:10.1520/E1242-97R14.2Lipnick,Robert L.,“Validation and Extension of Fish Toxicity QSARs andInterspecies Comparisons for Certain Classes of Organic Chemicals,”QSAR inToxicology and Xenobiochemistry,Elsevier,1985.3For 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.4The 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 screening test can also be saved.The value obtained in thisprocedure can be used as the preliminary estimate of the LC50in a full-scale test.5.2 Estimates can be used to set testing priority of groups ofnon-reactive and non-electrolytic chemicals.5.3 If the estimated value is more than 0.3 times theexperimental value,the mechanism of action is probablynarcosis.If less,the effect concentration is considered to reflecta different mechanism of action.5.4