Per. Mineral. (2008), 77, 2, 27-34 doi:10.2451/2008PM0010 http://go.to/permin

PERIODICO di MINERALOGIAestablished in 1930

An International Journal ofMINERALOGY, CRYSTALLOGRAPHY, GEOCHEMISTRY,ORE DEPOSITS, PETROLOGY, VOLCANOLOGYandappliedtopicsonEnvironment,ArchaeometryandCultural Heritage

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Abstract. — Calabrian ophiolitic deposits findindustrial uses in two areas depending on theconditions of the deposit: the first exploits thefriabilityof rocks, toobtain theaggregateused inlocalconcretes,whiletheseconduseconsistsoftheproductionofthemassiveblocksofstonesusedfordecorativeelements,frames,paving,flooring,lapidaryandjewelsart,etc.Weselectedthesetwominingandmillingmethods togainanunderstandingof theiroperationswiththeaimofassessingtheriskoftheworker’sexposuretoasbestosairbornefibers,andthepossibledispersionofsuchfibersinthesurroundingenvironment.Also,theworkingcyclerelativetotheproductionoflapidarymaterialwasinvestigatedinordertoassesstheriskoftheworker’sexposuretoairborneasbestosfibers.Furthermore,bothsquaresandstreetsoftheurbandistrictsneartheophiolitesquarriesandmillingplantswereinvestigatedbyairsampling to determine the possible dispersion ofasbestosfibersintothesepopulatedareas.Sampleswerecollectedontomembranefiltersandanalysedusing Scanning Electron Microscopy (SEM).ThequalitativecharacterisationofthefiberswascarriedoutbyEnergyDispersiveSpectroscopy(EDS).Theresults show that the highest values of the meantremolitefiberconcentrationsareobtainedduringthe

diamondwirecuttingoperation(0.071fiber/cm3)andthebroomingprocess(0.059fiber/cm3).Furthermore,about 42% of the respirable asbestos fibers arereleasedduringthecuttingoperations.Eventhoughthe worker’s exposure to tremolite fibers did notexceedtheregulatorylimitspecified,theyshouldbesuppliedwithsuitablepersonalprotectionequipmentinordertoreduceasbestosriskexposure.Furthermore,theworkersshouldbeeducatedandinformedabouttherisksrelatingtooccupationalexposuretoasbestosfibers.Theasbestosfiberconcentrationsobtainedbyenvironmental samplings performed in the urbandistrictsdonotexceedthelimitof1fiber/litre,asWorldHealthOrganizationrecommendsforurbanareas.However,inordertoreducethedispersionoftremolitefibersthebestavailable techniquesshouldbeadoptedandusedtoreduceexposure.

Riassunto.-IgiacimentiofioliticidellaCalabria,grazieallelorodiverseproprietà,vengonoutilizzatiin due particolari tipologie di lavorazioni. Taliattivitàsonostateesaminateal finedi identificareleprincipalifasidelciclolavorativo,letecnicheele apparecchiature utilizzate. La prima tipologia,sfruttandolafriabilitàdellerocce,consentediottenereilprodottousatoprincipalmentecomeinerteperlaproduzionedicalcestruzzoenelsettoredell’edilizia.La seconda invece, consiste nella produzione di

Calabrian ophiolites: dispersion of airborne asbestos fibers during mining and milling operations

aneta MaRia ZakRZewska 1,*,PietRo Paolo CaPone 1,antonino iannò 1,VinCenZo taRZia 1,antonella CaMPoPiano 2,egidio Villella 3andRenato giaRdino 3

1ISPESL,LaboratorioPolverieFibre,CentrodiRicerche,LameziaTerme(CZ)2ISPESL,DipartimentoIgienedelLavoro,MontePorzioCatone,Roma

3ASLn°6,S.P.S.A.L.,LameziaTerme(CZ)

*Correspondingauthor,E-mail:anetama@alice.it

28 a.M. ZakRZewska, P.P. CaPone, a. iannò, V. taRZia, a. CaMPoPiano, e. VillellaandR. giaRdino

grossiblocchidipietracompattausatiperlavorazionipiùparticolari,qualiadesempio,elementidecorativi,cornici,pavimentazioni,artelapidea,monili.

L’obiettivo del presente lavoro è di valutarel’eventualerischiodiesposizioneafibrediasbestoaerodispersedurante i processidi lavorazionedeimaterialiprovenientidagliaffioramentiofioliticielapossibiledispersionedi tali fibrenell’ambientecircostante.Atalfinesonostatieseguitiicampionamentipersonalidurantelalavorazionedeimaterialiofioliticiedalcunicampionamentiambientalinellevicinanzedellecaveedegliinsediamentiproduttivi.Icampionidiaria,raccoltisullemembranefiltranti,sonostatianalizzatiutilizzando ilMicroscopioelettronicoaScansionecorredatodiMicroanalisiaraggiXperlacaratterizzazionequalitativadellefibre.

La valutazione dell’esposizione professionalehaevidenziatochelaconcentrazionedellefibreditremoliteèinferioreailimitiprevistidallavigentenormativama è, tuttavia, necessario chevenganoadottate le norme di protezione indispensabili ailavoratoripotenzialmenteespostiarischioamianto.Inoltre,ènecessariocheglistessisianoformatiedinformati sui rischi connessi all’esposizione adamianto durante il lavoro. Dai risultati emergeche la concentrazione media di fibre respirabilidi tremolite è maggiore durante le operazioni deltagliodelle lastre con il filodiamantato (0,071 f/cm3) seguitodalprocessodibocciardatura (0,059f/cm3).È statoappurato, inoltre, checirca il 42%dellefibreriscontrateall’internodell’impiantovienerilasciatodurantelelavorazionideltaglio.Ivaloridelleconcentrazionidifibrediasbestoottenutidaicampionamenti ambientali effettuati nei comunisedidellecaveedegliinsediamentiproduttivinonsuperanoillimiteraccomandatodallaWorldHealthOrganizationparia1fibra/litroperlezoneurbane.Alfinedicontenereladiffusionedellefibrediamiantonell’ambiente devono essere adottate delle best available techniquesdisponibilisulmercatoperaltrerealtàproduttiveincuiilcontrollodelladispersionedifibreèessenzialesiapermotividiigienechedisicurezza.

key woRds: ophiolites, asbestos, tremolite, airborne fibers.

intRoduCtion

Theophiolites,agroupofbasicandultrabasicmagmaticassociationsofrocks,duetotheirtypical

dark greenish colours are called greenstones.InCalabria,inthesouthofItaly,thegreenstonefieldsoftheMountReventinohaveaconsiderableimportanceastheyareanimportantandeconomicresource.Thesematerialsareusedinbuildings,intheproductionof theornamentalstones,andasdecorative jewels.Unfortunately thesedepositscontainasbestosfibersthatmaybereleasedduringtheminingandmillingof thesegreenstones. Ifthesefibersarerespirabletheymaypenetrateintothelungtissueandconsequently,mayleadtoanasbestos-related disease (e.g., asbestosis, lungcancerormesothelioma)(SelikoffandLee,1978;McDonaldandMcDonald,1998;SuzukiandYuen,2002;Senyigit et al.,2004)

TheclassificationschemeofthegreenstonesandtheiruseinrelationtotheirofasbestoscontentaredefinedintheMinisterialDecreeof14May1996.Suchclassificationisbasedonthepetrographicinformation.TheophiolitesoftheCalabrianArcareconsideredtohavebeenpartoftheneo-TethysoceaniclithospherethatonceseparatedtheEuropeanandAfricanPlates(Guerrera et al., 1993;Cello et al., 1996).TheCalabrianPeloritanArclinksthesouthernApenninicchaintotheMaghrebianchain(Amodio-Morelli et al. 1976)andissubdividedinto northern (Sila and Catena Costiera) andsouthernsectors(Bonardiet al.,1980;Tortorici, 1982).ThenappesystemofthenorthernCalabrianPeloritanArcissubdividedintothreemaintectoniccomplexes:theApennineComplex,theLiguridecomplexand theCalabrideComplex (Ogniben, 1973). In the literature, theCalabrianLigurideComplexhasbeensubdividedintoseveraltectono-metamorphicunits:theDiamante-Terranovaunit,theMalvitounit,theGimigliano-MonteReventinounit and theFridounit (Amodio-Morelli et al., 1976). The Gimigliano-Monte Reventino unitconsistsofserpentinites,metabasalts,metagabbros/metadoleriteswithametasedimentarycovermadeup of marble alternating with calcschists andquarzites(Piluso et al., 2000).Theserpentinites(withcloselyassociatedophicalcites)aremainlycomposedbyserpentine,actinoliteandchloritewithminor relictsofspinel,orthopyroxeneandolivine.Themetabasitesaremainlyrepresentedbygreenishtogreyishepidote-chlorite-actinoliteschists.Themineralassociationincludeschlorite,epidote,actinolite,whitemica,albite,quartzandlawsonite.Thebandedtextureischaracterisedby

Calabrian ophiolites: dispersion of airborne asbestos fibers during mining and milling operations 29

thinalternating layersofalbiteandsubordinatequartz together with epidote, amphibole andchlorite(Piluso et al., 2000).

Method and teChniques

Thegreenstones,duetotheirdifferentproperties,areusedintwoparticularmanufacturingprocesses.Thefirsttypeexploitstherocksfriabilityallowingit to be used principally as the inert filler forconcreteproduction.Theseconduseconsistsoftheproductionofthelargeblocksofstonesusedmainlyfordecorativeelements,frames,pavements,indoorflooring,lapidaryandjewels.Andinturntherearetwodifferentmillingprocessused.

The production of the friable material issubdivided in two phases, the first takes placedirectlyinthequarrywithselectionofrawmaterialandthesecondoccursatthecrushingandsieveingplant where the material, transported from thegreenstonequarry,isunloadedinsidethehopperandcrushed.Nextitismovedbyaconveyorbelttovibrating-sieveswhere it is subdivided in tohomogeneoussizeclasses.Thefinalprocessingphaseconsistsofloadingthematerialontrucksfortransport.Itisworthnothingthatthecrushingandsizingplantisequippedwithaclarificationsystemofrecycledwaterandmud.

The ophiolitic site, where the rock is moremassive, situated, for example, near the urbandistricts of Conflenti, are characterized by aquarryingactivityofthelargeblocksofstone.Theworkingcycle,inthiscase,differssomewhatasafunctionoftheenduseoftheproduct.Regardless,oftheproduct,thefirststepiscuttingtheblocksandtransportingthemoutofthequarry.Recalltheblocksarecutintoslabsbyeitheradiamond-wireordiamond-blades.

Basedon the thickness,hardness, colourandveinswithin the slabs, a series of thedifferentsuperficial treatments are performed to obtaindifferentproducts.Thepolishingprocessproducesa product used for pavements and decoration.The brooming process is obtained by rotatingplatesequippedwithWidia-tips,thatgivesslapsa rough and irregular look.Theseproducts areusedforstreetpavementsandoutdoordecoration.Theslapsobtainedbythepolishingorbroomingprocess are cut with diamond blades to obtain

tiles which represent the finished product. Forsomeapplications, theslapsareglued together.Theseworkingprocessesareperformedinawetabatementsystem,exceptforthestone-masonorstone-breaker,whichareperformeddirectlyontheblocksandslabswithchisels.

The working cycle relative to production oflapidary material was investigated in order toassesstheriskoftheworker’sexposuretoasbestosairbornefibers.

In order to verify the presence of asbestosboth bulk and air samples were characterized.AnalysesoffibrousmineralswerecarriedoutonnaturalsamplesoftheophioliticrocksoccurringintheneighbouringPlataniaandConflentiareas.Fig.1showtheGeologicalmapoftheCalabrianPeloritanArc,northernsector(Piluso et al., 2000),andthelocationoftheareaofstudy.

The personal exposure data were collectedbypersonalsamplingsaccordingtoItalianLawDecree277/91.TheportablesamplersAcquariaAcquaria(mod.Personal)and metallic selectors were usedandmetallicselectorswereusedwithaflowrateofonel/min.Polycarbonatefilterswithaporesizeof0.8µmandadiameterof25mmwereused,andthevolumeofairwasestablishedinrelationtothequantityoftheairbornedust.

Bothsquaresandstreetsnearthequarriesandthe greenstone processing plants of the urbandistricts of Decollatura, Platania and Conflentiwere sampled. Temperature, relative humidity(R.H.)andwindvelocity(W.V.)weredeterminedbyathermoigrometer(mod.Testo445).

Thesamplefilterswerepreparedaccordingtothe analysis method specified by a MinisterialDegree 6/9/94: Quantitative determination of airborne asbestos fiber concentrations in indoor environments. A portion of each filterwas transferred onto an aluminium stub, andthencoatedwithathinlayerofgoldtoincreasetheconductivity,andanalysedwithaScanningElectronMicroscope(Leo1430).ThequalitativecharacterizationofthefiberswerecarriedoutbyEnergy Dispersive X-ray Spectroscopy (EDS,IXRFSystemsmod.500).BasedonthePoissoniandistribution,themethodvariabilitywasestimated.

30 a.M. ZakRZewska, P.P. CaPone, a. iannò, V. taRZia, a. CaMPoPiano, e. VillellaandR. giaRdino

Results

T h e f i b r o u s v a r i e t y o f t r e m o l i t eCa2Mg5Si8O22(OH)2,arelativelycommonmineralin metamorphic rocks, was found in the bulkmetamorphic rocks, was found in the bulk rocks, was found in the bulksamplesfromthegreenstoneoutcrops(Figs.2-3).Fig.4showsanSEMphotographofanairborneasbestos fiber deposited on the surface. Thepresenceofthevarietyoftremolitewasconfirmedbyaqualitative fiberanalysis.Fig.5 showsanexampleoftheEDSspectraofatremolitefiber.

The values of personal exposure and thecorresponding values of the upper and lowerconfidencelimits,forthePoissoniandistribution,obtained for each duty during the lapidaryproductionareshowninTable1.Theresultsshow

Fig.1–GeologicalsketchmapoftheCalabrianPeloritanArc,northernsector(Piluso et al., 2000),andthelocationofthestudiedarea.1.ApennineUnitsComplex;2.OphioliteUnits;ContinentalcrustUnits;3.Castagnaunit;4.CalabrideUnits;5.sedimentarycoveroftheCalabrideUnits;6.LigurideComplexoftheCalabrian-Lucanianboundary;7.Miocene-Oligocenesedimentarysequences.

Fig.2–SEMmicrographofthebulksampleusingx2000magnification.

Calabrian ophiolites: dispersion of airborne asbestos fibers during mining and milling operations 31

thatthehighestvaluesofthemeanasbestosfiberconcentration are obtained during a diamondwirecuttingoperation(0.071fiber/cm3)andthebroomingprocess(0.059fiber/cm3).Furthermore,about42%of the respirable asbestos fibers arerespirable asbestos fibers areasbestos fibers arefibers arearereleasedduring thecuttingoperationsasFig.6indicates.Last, the resultsof the air samplingsperformed in urban districts of Decollatura,PlataniaandConflentiareshowninTable2.ThehighestmeanconcentrationofasbestosfiberswasfoundinurbandistrictofDecollatura(0.18fiber/

litre)andassumedtooccurbecauseofthepresenceofthegreenstoneworkingplantinthatarea.

disCussion

Our sampling showed that both types ofgreenstone outcrops contain fibrous tremolite.Thepresenceofamphibolesgivesthegreenstonesparticular physical properties that make themsuitable fordifferent industrial applications. In

Fig.3–EDSspectrumofabulksample.

Fig.4–SEMmicrographofairbornetremolitefiberusingx7000magnification.

32 a.M. ZakRZewska, P.P. CaPone, a. iannò, V. taRZia, a. CaMPoPiano, e. VillellaandR. giaRdino

fact, theoutcropswitha lightgreencolour arerichinamphiboles, fragile, and easily broken intoamphiboles, fragile, and easily broken intofragile,andeasilybrokenintopieces; forthisreasontheyareused forconcreteproductionandasaggregate.Therockswithadarkgreencolourcontain feweramphibolesandaremoredurable;theyareusedinpavements,indoorflooring,andlapidaryproduction.

The estimation of the airborne asbestosconcentrationconfirms that the fibersdiffusiongeneratedduringquarryingactivitiesdependsonthetypeofthematerialextracted(Falcone et al.,2005).Thefiberconcentrationsarehigherinthequarrycharacterizedbyfriablematerialthaninthequarrywiththepresenceofthemassiveblocks;however,duringnaturalweatheringthediffusionofasbestosfibersisverylow.

The evaluation of the worker’s exposure toasbestosfibersduringlapidarymaterialproductionshowedthattherespirablefiberconcentrationsoftremolitearelowerthanthelimitof100fiber/litrecurrentlyrecommended.Evaluatingtheprincipalphasesoftheworkingcycle,thecuttingoperationproducedthelargestofrespirablefibers.Inthisprocess about 42% of the asbestos respirablerespirablefibers were released; during both diamond bladewerereleased; during both diamond blade;duringbothdiamondbladecutting (13%)anddiamondwirecutting (29%)operations.The appropriate abatement systemsshouldbeused todecrease thefibersdiffusion;for example the continuous use of water jetsduringthevariousworkingphasescontributestothereducingofworker’sexposure.Theasbestosfibersconcentrationsobtainedbyenvironmental

table 1 — Mean asbestos fiber’s concentrations obtained by personal samplings during lapidary production

DutyNo.of Conc. LCL UCL

samples Meanvalue(fiber/cm3) (fiber/cm3) (fiber/cm3)

Diamondwirecuttingoperator 5 0.071 0.042 0.093Diamondbladecuttingoperator 6 0.036 0.021 0.049Stone-breakeroperator 5 0.029 0.006 0.064Brooming 6 0.059 0.042 0.087Polishing 5 0.040 0.025 0.074Gluing 5 0.030 0.023 0.042

Urbandistrict No.ofsamplesConc.

LCL(fiber/L) UCL(fiber/L)MeanValue(fiber/L)

Decollaturaa 8 0.18 0.06 0.92

Conflentib 4 0.03 0.00 0.40

Plataniac 3 0.00 0.00 0.40aTemp.21.1°C;R.H.56.1%bTemp.21.5°C;R.H.51.0%;W.V.1.9m/s.W.V.0.9m/s.cTemp.17.5°C;R.H.63.5%;W.V.1.0m/s.

table 2 — The respirable fiber concentration of tremolite obtained by environmental samplings carried out in urban district next to the quarries and greenstone working plants

Calabrian ophiolites: dispersion of airborne asbestos fibers during mining and milling operations 33

samplings carried out in the urban districts ofurban districts ofDecollatura,PlataniaandConflentidon’texceedthe limit of one fiber/litre, as World HealthOrganization (WHO “Air quality guidelines for Europe”, 1987) recommendsforurbanareas.

ConClusions

Theresultsofthisstudyshowthatthepersonalexposures to airborne asbestos fibers are keptbelowthecurrentlimitvaluesinItaly;however,theworkersshouldbesuppliedwithsuitablepersonalprotectionequipmentinordertoreduceasbestosriskexposureevenfurther.Inordertoreducethedispersionof tremolite fibers thebestavailabletechniquesshouldbeadoptedandusedinotherproductionareaswherefibercontrolisessential

for hygiene and industrial safety. Furthermore,the workers should be educated and informedabouttherisksrelatingtooccupationalexposuretoasbestosfibers.Thepresenceoftheophioliticsitesdoesnotseemtoplacethelocalpopulationatanelevatedrisk;however,furtherstudyisneededonthedispersionofthefibers,particularlyinthedistrict of Decollatura where, unlike the otherareas,agreenstonemillingplantissituatedintheurbancentre.

Examinations of the asbestos fibers by SEManalysisshowthattheirdimensionsarevariable.Further examination is necessary to determinethe dispersion of finest asbestos fibers. Thesefiberscancrossthepulmonary-pleuralbarrierandthereforemayleadtoincreasesinmesotheliomaandotherbenignpleuralmanifestationsasrecent

Fig.5–EDSspectrumofairbornetremolitefiber.

Fig.6–Percentagesoftremolitefibersfoundduringprincipalworkingphases.

34 a.M. ZakRZewska, P.P. CaPone, a. iannò, V. taRZia, a. CaMPoPiano, e. VillellaandR. giaRdino

researchesdemonstrate(Chiappino,2006;Tomatiset al.,2006).

aCknowledgeMents

Wewish to expressourdeepest appreciation toprof.R.Cirrincioneandprof.M.E.Gunterfortheirconstructive reviews, that greatly improved thispaper.

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