Mokoenaetal2016

See discussions, stats, and author profiles for this publication at: assessment of microcystins from thehousehold’s drinking waterArticle in Applied Ecology and Environmental Research · April 2016DOI: 10.15666/aeer/1403_695710CITATIONS0READS511 author:Michael MokoenaTshwane University of Technology5 PUBLICATIONS 33 CITATIONS SEE PROFILEAll content following this page was uploaded by Michael Mokoena on 20 July 2016.The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original documentand are linked to publications on ResearchGate, letting you access and read them immediately.Mokoenaetal.:Hazardassessmentofmicrocystins-695-APPLIEDECOLOGYANDENVIRONMENTALRESEARCH14(3):695-710.●ISSN15891623(Print)●ISSN17850037(Online)DOI:2016,ALÖKIKft.,Budapest,HungaryHAZARDASSESSMENTOFMICROCYSTINSFROMTHEHOUSEHOLD’SDRINKINGWATERMOKOENA,M.M.1*‒MUKHOLA,M.S.1‒OKONKWO,O.J.21DepartmentofEnvironmentalHealth,TshwaneUniversityofTechnology,PretoriaCampus,StaatsartilleryRoad,P/BagX680,Pretoria,0001,RepublicofSouthAfrica(phone:[phone];fax:[phone];email:[e-mail])2DepartmentofEnvironmental,WaterandEarthSciences,TshwaneUniversityofTechnology,ArcadiaCampus,175NelsonMandelaDrive,Arcadia,Pretoria,0083,P/BagX680,Pretoria,0001,RepublicofSouthAfrica(phone:[phone];fax:[phone];email:[e-mail])*Correspondingauthor:email:[e-mail](phone:[phone];fax:[phone])(Received27thNov2015;accepted23rdApr2016)Abstract.Cyanobacteriaproducetoxinswhicharehazardoustothehealthofpeoplewhoareusingwaterthatiscontaminated.ThehazardquotientsuggestedbyUnitedStatesEnvironmentalProtectionAgency(USEPA)wasusedtoassessthehumanhealthhazardofusingcontaminatedwatercontainers.Therewasnostatisticallysignificantdifference(P=0.5511)inthelevelofmicrocystinbetweenbloominganddecayingseasons.Findingsshowthatalltreatedwatersamplesinthecontainerswerebelowthe1.0µg/Llevel,whichunderscorethisimportantissue:drinkingwaterfromtreatedwaterincontainershasnoadversehealtheffectwhencomparedtodrinkingwaterfromnon-treatedwatercontainers,whetherusedbyadultsorchildren.Inconclusion,collectingandstoringofeitherpre-treatedornon-treatedwaterusingcontainersneedspost-treatmentbeforedrinking.Keywords:hazardquotient,microcystinsmodelling,cyanobacteria,watercontainersIntroductionItisbelievedthatrecreationalandoccupationalcontactwithcontaminatedwaterarethemostcommonformsofexposuretocyanobacterialtoxinsindams,riversandmarinewater(Azevedoetal.,2008).InthereportsofHoffman(1976)andDuyetal.(2000)itwasdiscoveredthatlong-termexposuretolowlevelsofcyanotoxinsmayalsooccurinareaswhichreceivetreateddrinkingwater,asmostoftheconventionalwatertreatmentprocessesareineffectiveinremovingcyanotoxins(DWAF,1996).OberholsterandAshton(2008)reportedthatextracellulartoxinconcentrationsremainedconstantafterflocculationandfiltrationinaconventionalwatertreatmentplant.Dalyetal.(2007)evaluatedtheeffectofchlorineonthecellintegrityoftoxicMicrocystisaeruginosa.Flowcytometrydeterminedlive(viable)anddead(nonviable)Microcystiscells,anditwasfoundtohaveahigherconcentrationofchlorinethanwhatwassuggestedbyNicholsonetal.(1994).ThedifferencewasthatDalyetal.(2007)lysedthecell,whilstNicholsonetal.(1994)degradedthetoxinsdirectly.Tsujietal.(1997)reportedthatchlorinationandozonationareeffectivemeansfortheremovalofmicrocystins.Nicholsonetal.(1994)reportedthatachlorinedoseof3mg/Liseffectiveineliminatingthepresenceofmicrocystinsindrinkingwaterifaresidualof0.5mg/Lissustainedfor30minutes.Thisisbecausechlorinereactswithmicrocystinorganiccompoundstoformtrihalomethanes,whichmaybealsotoxicandcarcinogenictoMokoenaetal.:Hazardassessmentofmicrocystins-696-APPLIEDECOLOGYANDENVIRONMENTALRESEARCH14(3):695-710.●ISSN15891623(Print)●ISSN17850037(Online)DOI:2016,ALÖKIKft.,Budapest,Hungaryhumans(Muyodi,2009).Chlorinebleachisinexpensiveandreadilyavailable,instores,forthepublictopurchase.Allstudiesdemonstratedthatchlorinewaseffectiveindegradingmicrocystinsinwater(Tsujietal.,1997andNicholsonetal.,1994).TheuseofthecorrectconcentrationofbleachandtherightpHhasbeenproventoremovemicrocystinsbyupto99%indrinkingwater(DWAF,1996;Backeretal.,2008).Toxiccyanobacteriaarerecognisedashazardoustohumanandanimalhealthandassessmentsarecarriedouttodetermineenvironmentalhealthproblems(Ahmedetal.,2008).However,thoroughinvestigationofhumanillnessesanddeaths,followingexposuretomicrocystins,arerequired.Sometoxinsproducedbycyanobacteriaarecarcinogens.Non-carcinogenicmicrocystinshavebeenthemostwidelyinvestigatedtoxingroup.Thehealthrisksposedbyexposuretomicrocystinsaredifficulttoquantify,sincetheactualexposureandtheresultingeffectshavenotbeenconclusivelydetermined,especiallyinrelationtohumans(Chenetal.,2009).Microcystinexposurecanalsooccurthroughcontactwithoringestionofalgalscums.Three