july 11, 2017 identify the hazards posed to people by ... science-based, public health document that...

July11,2017CommentsontheNationalToxicologyProgram’s“DraftReportonCarcinogensMonographonHaloaceticAcidsFoundasWaterDisinfectionBy-Products”EnvironmentalWorkingGroup,anonprofitresearchandpolicyorganizationwithofficesinWashington,D.C.;SanFrancisco,California;andAmes,Iowa,submitsthisletterinsupportoftheNationalToxicologyProgram’seffortstoevaluateandidentifythehazardsposedtopeoplebyhaloaceticacidsindrinkingwaterandtheproposaltolistthesechemicalsintheReportonCarcinogens.Thisreport,publishedbytheU.S.DepartmentofHealthandHumanServices,isacongressionallymandated,science-based,publichealthdocumentthatNTPpreparesandupdatesregularly.Itservesasabasisforpublicpolicydecisionsmadebyvariousfederalandstateagenciestaskedwithprotectionofpublichealth.Haloaceticacidsarecommondrinkingwatercontaminantsthatformwhendisinfectantssuchaschlorineinteractwithplantandanimalwasteinsourcewater.EWGhasbeenresearchingandeducatingAmericansaboutthetoxicityandconcernsofwaterdisinfectionbyproductsforalmosttwodecades(EWG2013).Giventhestrongevidenceofhaloaceticacidcarcinogenicityfromanimalstudiesandwidespreadhumanexposuretothesechemicals,EWGfullysupportsandagreeswiththeNTP’sproposedclassificationofthesixfollowinghaloaceticacidsas“reasonablyanticipatedtobehumancarcinogens”:

• Dichloroaceticacid,containingtwochlorineatoms;• Dibromoaceticacid,containingtwobromineatoms;• Bromochloroaceticacid,containingonebromineandonechlorineatom;• Bromodichloroaceticacid,containingonebromineandtwochlorineatoms;• Chlorodibromoaceticacid,containingonechlorineandtwobromineatoms;• Tribromoaceticacid,containingthreebromineatoms.

Thisproposedclassificationisgroundedinextensiveresearchshowingthattheabovehaloaceticacidsproducetumorsinexperimentalanimalsandcanbeexpectedtosimilarlycausecancerinhumans.EWGreviewedtheanalysispresentedintheDraftReportandconcurswiththeNTP’sconclusionthatthislistingisbothjustifiedandnecessary.Whiledrinkingwaterdisinfectioniscriticaltosavelivesandpreventillnessfromdisease-causingmicroorganisms,whenchlorineandotherdisinfectantsreactwith

organicmatterinthewater,harmfuldisinfectionbyproductslikehaloaceticacidsareformed.Thesebyproducts,thesecondlargestgroupofhalogenateddisinfectionbyproducts,arefoundinthewaterofmorethan250millionAmericans,increasingtheimportanceoftheNTP’sproposedclassification.EWGalsourgestheNTPtoclassifytrichloroaceticacidas“reasonablyanticipatedtobeahumancarcinogen,”basedonevidenceofliverneoplasmsinmaleandfemalemiceexposedtothischemicalthroughdrinkingwater,asdocumentedbytheCaliforniaOfficeofEnvironmentalHealthHazardAssessmentinitsreviewofthischemical(OEHHA1999).EWGalsoraisesconcernsaboutthehealtheffectsandpotentialcarcinogenicityofiodine-containinghaloaceticacids.Inthedraftmonograph,NTPdidnotidentifysufficientdataforimmediateclassificationofiodoaceticacids.Yet,researchshowsthatiodine-containingdisinfectionbyproductsaregenotoxicinmammaliancells(Richardson2008),andmoreresearchonthesecompoundsisurgentlyneeded.ThepublichealthimplicationsoftheNTPresearchonhaloaceticacidsaresignificantbecausehundredsofmillionsofAmericans,childrenandadults,areexposedtothesedisinfectionbyproducts,includinghaloaceticacids,everydaywhentheydrinktapwater,shower,orswiminpublicpools.Theidentificationofthecancerhazardsofhaloaceticacidsisthenecessaryfirststeptoprotectingthepublicfromcancer-causingdisinfectionbyproducts.Inconclusion,EWGfirmlybelievesthathaloaceticacidsshouldbelistedinthenationalReportonCarcinogensas“reasonablyanticipatedtobehumancarcinogens.”Thegeneralpublic,academicresearchers,othergovernmentagencies,andwaterutilitiesalllookuptotheNTPforanunbiasedassessmentofcancerrisksfromchemicalsinourenvironmentandinourwater.ThehealthofallAmericans–especiallyvulnerablepopulationsandchildren–shouldbesafeguardedfromthetoxiceffectsofwatercontamination,andNTPresearchandanalysisisessentialinthisprocess.Thankyoufortheopportunitytocommentonthisimportantassessment.SubmittedonbehalfoftheEnvironmentalWorkingGroup,TashaStoiber,Ph.D.,SeniorScientistEnvironmentalWorkingGroup

500WashingtonSt.Suite400SanFrancisco,CA94111(415)963-0750ReferencesEnvironmentalWorkingGroup,2013,WaterTreatmentContaminants:ForgottenToxicsinAmericanWater.Availableatstatic.ewg.org/reports/2013/water_filters/2013_tap_water_report_final.pdf?_ga=2.236991296.1736848890.1499706616-2009753781.1455041018NationalToxicologyProgram,2017,DraftReportonCarcinogensMonographonHaloaceticAcidsFoundasWaterDisinfectionBy-Products.Availableatntp.niehs.nih.gov/ntp/about_ntp/monopeerrvw/2017/july/haadraftmonograph.pdfOfficeofEnvironmentalHealthHazardAssessment(OEHHA),1999,EvidenceontheCarcinogenicityofTrichloroaceticAcidanditsSalts.Availableatoehha.ca.gov/media/downloads/crnr/tcaf.pdfS.D.Richardsonetal.,2008,OccurrenceandMammalianCellToxicityofIodinatedDisinfectionByproductsinDrinkingWater.EnvironSciTechnol.42(22):8330-8.