ASTM_D_5257_-_11.pdf

Designation:D525711Standard Test Method forDissolved Hexavalent Chromium in Water by IonChromatography1This standard is issued under the fixed designation D5257;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.Scope*1.1 This test method covers procedures for the determina-tion of dissolved hexavalent chromium in wastewater,surfacewater,and drinking water.1.2 The precision and bias of this test method has beentested in reagent water and industrial wastewater and has beenfound suitable over the range of approximately 1 to 1000 g/L.See Table 1 for details.Higher levels can be determined byappropriate dilution.1.3 Samples containing very high levels of anionic species(that is,chloride,sulfate,etc.)may cause column overload.Samples containing high levels of reducing species(that is,sulfides,sulfites,etc.)may cause reduction of Cr(VI)to Cr(III).This can be minimized by buffering the sample to a pH of 9 to9.5,filtering it,storing it at 6C.aA holding time of 28 daysmay be used if the user can demonstrate that such holding timedoes not affect sample integrity per US EPA 40 CFR 136 PartII.1.4 The values stated in either SI or inch-pound units are tobe regarded as the standard.The values given in parenthesesare for information only.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 determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1066 Practice for Sampling SteamD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis2.2 EPA Standard:EPA Method 218.6 Determination of Dissolved HexavalentChromium in Drinking Water,Groundwater and IndustrialWastewater Effluents by Ion Chromatography3US EPA 40 CFR 1363.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 eluentthe ionic mobile phase used to transport thesample through the ion-exchange column.3.2.2 resolutionthe ability of a column to separate con-stituents under specified test conditions.4.Summary of Test Method4.1 Afixed volume of buffered and filtered sample,typically100 L,is injected into the eluent flow path and separated byanion exchange using an ammonium sulfate based eluent.4.2 After separation,the sample is reacted with an acidicsolution of diphenylcarbohydrazide.Hexavalent chromiumreacts selectively with this reagent to form the characteristicviolet colored complex.4.3 The eluent stream passes through a photometric detectorfor detection of the chromium diphenylcarbohydrazide com-plex by visible absorbance at 530 nm.Absorbance is propor-tional to the hexavalent chromium concentration.5.Significance and Use5.1 Hexavalent chromium salts are used extensively in themetal finishing and plating industries,in the leather industry as1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved March 15,2011.Published April 2011.Originallyapproved in 1992.Last previous edition approved in 2009 as D5257 09.DOI:10.1520/D5257-11.2For 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.3Available from Superintendent of Documents,U.S.Government PrintingOffice,Washington,DC 20402.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 a tanning agent,and in the manufacture of paints,dyes,explosives,and ceramics.Trivalent chromium salts are used asmordants in textile dying,in the ceramic and glass industry,and in photography.Chromium,in either oxidation state,maybe present in wastewater from these industries and may also bedischarged from chromate-treated cooling waters.5.2 Hexavalent chromium is toxic to humans,animals,andaquatic life.It can produce lung tumors when inhaled andreadily induces skin sensitization.It is not known whethercancer will result from ingestion of chromium in any of itsvalence states.5.3 Ion chromatography provides a means of separating thehexavalent chromium