An%c3%a1lisis de Riesgos

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ANALISIS DE RIESGOS ~'f;~~;w~+?'I'~~~~!('ILa evaluacin e riesgos mbientalesersasobre -::1

el aumentoen la probabilidadde que un daoocurra.Existe un riesgo en cadauna de las actividadesque levamosa cabo.El riesgoa 10 argo denuestravida es 1 o 100%Uno de los propsitosde la evaluacinde riesgoses proporcionarun punto de partida en el balanceentreun incrementoaceptable el riesgoy loscostespara controlar el riesgoa esenivel.La evaluacinde riesgospuededi'.Tidirse n lassiguientesetapas:- Identificacin del txico- EvaluacinDosis-Respuesta

- Evaluacinde la exposicin-Caracterizacin el riesgo


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t:i ~ble 14.1 Risk of death for Americans from various activities.~:~~ Approximate Number Approximate Odds Lifetime Risk~ of U.S. Deaths-Each of Death from of Death fromt Cause of Death Year from This Cause" This Cause This Cause

~.Diseaseall kinds) 2,000,000 1 n 1.1 9.1 X 10-1Heart isease 770,000 1 in 2.7 3.7 X 10-1Cancerall kinds) 480,000 1 n 4.4 2.3 X 10-1Accidentsall kinds) 95,000 i in 22 4.5 X 10-2Autoaccidents 48,000 1 n 44 2.3 X 10-2Diabetes 37,000 lin 57 1.8 X 10-2Suicide 31,000 1 n 68 1.5 X 10-2Homicide 21,000 1 in 100 1.0 X 10-2Drowning 5,900 1 in 360 2.7 X 10-3fire 4,800 1 in 440 2.3 X 10-:3Asthma 4,000 1 n 530 1.9 X 10-3Firearm ccident 1,500 1 in 1,400 7.1 X 10-4Viral hepatitis 1,000 1 n 2,100 4.8 X 10-4

. Electrocution 850 1 n 2,500 4.0X 10-4Car-trainaccident 570 1 n 3,700 2.7 X 10-4Appendicitis 510 1 n 4,100 2.4 X 10-4Pregnancy nd elated 470 1 n 4,500 2.2 X 10-4Lightning 78 1 n 27,000 3.7 X 10-5Aood 58 1 n 36,000 2.8 X 10-5Tomado -58 1 in 36,000 2.8 X 10-5Fireworks 8 1 n 260,000 3.8 X 10-6BotulisIJl 2 1 n 1,100,000 9.1 X 10-7o The number 01 deoths Irom 011 auses is 2.1 million, out 01 a total U.S. populotion 01245 million in 1988.Source: Bosed on USHHS, 1988.

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- TOXICIDAD AGUDAEfectoscausadosras un corto periodo de tiempotras la exposicinal compu~sto umico.Una forma de describirlo es mediante a cantidadde compuestoque es necesario ara mataralorganismo.Se sueleexpresaren mg/kg. No todoslos miembrosde una poblacinreaccionan e lamisma forma.LDso= Dosis que mataal 50% de la poblacin

TABLE 4.6 A conventional rating system or the acute toxicitv of chemicals nhumans .Probable lethal oral clase or humans

Toxicity rating Dose (mg/kg of body weight) For average adult-l. Pr.actically nontoxic more than 15.000 More than 1 quar.2. Sllghtly tOXIC 5,000-15.000 1 pint to 1 quart3. Moderately toxic 500-5,000 1 ounce to 1 pint4. Very toxic 50-500 1 teaspoon to 1 ounce5. Extremely toxic 5-50 7 drops to 1 tea:.poon6. Supertoxic Less han 5 Less han 7 drops

100 100.?:' Chemical A .?:' ChemicalA ical C... ...'.: '.:c cE 50 E 50C C" "~ ~" "~ O ~ O

100 LD50 1000 LDso 10,000 LDso LD50Dose (mg/kg of body weight)- Dose-

j (a) (b)FIGURE4.4 Dose-response mortality curves for acure oxicity: (a) Chemical A is always more toxic than B; (b) butChemical A is less oxic than C at low clases ven though it has a lower LDso.I


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,TOXICIDAD CRONICALos organismos stnsujetosa una exposicinprolongadaduranteun periodo mportantede su vidaSerepresenta l riesgo de efectosadversos obre a salud rentea la dosis(mg/kg d). Para a dosisse oma una exposicinmediasobre oda a vida (70 aospara os humanos).Parasustancias ancergenase asumeque cualquiercantidadinduceun riesgo, por lo que a curvapasapor el origen. Para assustancias o cancergenas ormalmente e suponeuna dosisumbral por debajode la cual no hay respuesta.Cuandose hacenensayos on animalesse suele ntroducir unfactor de escalado ara os humanos

Carcinogen Carci~ogenLinear. Nonlmear,no threshold no threshold1 NoncarcinogenVI~


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,INDICE DE PELIGROSIDAD PARA,SUSTANCIAS NO CANCERIGENAS

Se asumeque existe un umbral por debajodel cual no existeincrementoen los efectosadversos obre os valoresnormales.La menor dosisadministradaque produceefectossedenomina LOAELs) lowest-observed-adverse-effectevelsLa mayor dosisadministradaque no produceefectossedenomina NOAELs) No-observed-adverse-effectevelsDosis de referencia RfD)= Consumodiario aceptableSeobtienedividiendo NOAEL por un factor de seguridad,normalmente10.

tuU)~~~

Dose (mg/kg/day) -FIGURE.. 11 The re~erence ose RfD is the no-observed-adverse-effects-levelNOAEL) divided bncertamty factor typlcally between 10 and 100). yan


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,INDICE DE PELIGROSIDAD PARA,SUSTANCIAS NO CANCERIGENASEstablecidoel RtD debecompararsea exposicin mg/kg d) con l.

Dosis media diaria en el periodo de exposicinCuota de peligrosidad=RtD

TABlE 4.11 Oral RfDs for chronic noncarcinogenic ffectsof selectedchemicals.Chemical RfD (mglkg-day)Acetone 0.100Arsenic 0.0003Cadmiurn 0.0005Chloroform 0.0101,1-dichloroethylene 0.009cis-l,2-Dichloroethylene 0.010Fluoride 0.120Mercury (inorganic) 0.0003Methylene chloride 0.060Phenol 0.600Tetrachloroethylene 0.010Toluene 0.2001,1,1- richloroethane 0.035Xylene 2.000 \-

Source:U.S.EPA. http://www.epa.gov/iris

Cuotasde peligrosidad nferioresa 1 implican que no existe unriesgo significativo.,lndice de peligrosidad= Sumade as cuotasde peligrosidad


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"roble 14.4 Referencedo~e values for selected chemicals.Substance 0--' ...~~ , " ., - - ral RfD (rng/kg-da) InhaledRfD (~~~Metals and InorganicsAmmonia - 2.86 10-2Arseruc 3 x 10-4Beryllium 2 X 10-3 -

. 5.7 X 10-6Cadlnlum 1OX 10-3 (d. )let 6.15.0 x 10-4 (water) 6 1Chlorine .

. 0.1 5.7 X 10-5: ChrolnlumVI 3 X 10-3 ' 2.86 X 10-5I Hydrogenhloride -I 5.71 X 10-3,Manganese 1 4 -l.X 10 (dlet) 1.43 X 10-'

4.60 X 10-2 (water) 1.43 X 10-5Mercury -. 8.57 X 10-5Seleruum 5.0 X 10-:3Zinc 3 X 10-] -

1 --Organic CompoundsCarbondisulfide O1 02

I Chloroform 1 X 10-2 ~I Formaldehyde 0.2 i n-Hexane -2 -! 6.00 X 10 5.71 X 10-2

1, Methanol 5 X 10-1 -----Methyl ethyl ketone 06 --. - -' 1 M th .' 0.286ylene chlonde 6.0 X 10-2 0.857

Styrene " 0.2 0.286Tetrachloroethylene 1OX 10-2. 0.171. Toluene O2 0.114Xylene 2.0Source: RNl,2000;USEPA,1999.

roble 14.5 Sources of uncertainty in risk assessment.-Sources -,' Contaminant Pathways ReceptorsuUJ:\;C~ :::,:'- - .

Lack of informationon source Unknown pattemof subsurface Limitations of the dose-response10cation(s) heterogeneity models:

Poorly knownhistory of contaminant Complexitiesdue o naturaland . xtrapolation f hazardand oxicityreleases anthropogenic tresses dataUnknownvariability n massor In~bility to define and characterize . nsufficientdata o identify hazards rconcentration istributionsof physical.chemical,and biological ate dose-responsessessmentelationshipcontamin~ts and ransportprocesses .Model selection

Complexity n the chemical Limitations of mode1s f contaminant . ararneter stimation orcomposition f contaminants fate and ransportprocesses dose-response ode1

Difficulties in estimatingparametersor Problems haracterizing xposure ndcontaminant ate and ransportmodels outcome:. dentificationof toxicants. dentification of target populationover ime

. ariability n receptorsSource:NRC, 1999.


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TABLE4.10 ExampleEPA Exposure actors ecommendedor RiskAssessmentsExposure Exposure .Exposure Dai!y frequency. duration. ;

Land use pathway intake daysiyear years Body weight. kgResidential Ingestion of 2 L (adult) 350 30 70 (adult)potable water I L (chi!d) 15 (chi!d)

Ingestion of soil 200 mg (child) 350 6 15 (child) ~and dust 100mg (adu!t) 24 70 (adult)

Inhalation of 20 m) (adu!t) 350 30 70contaminants 12m' (child)

Industria[ and Ingestion of 1 L 250 25 70commcrcial potablc:water

Ingestion of soi! 50 mg 250 25 70 :anddust !;

Inhalatio~ of 20 m) (workday) 250 25 70 fcontammants .Agricultura! Consumption of 42 g (fruit) 350 30 70 i

homegrown produce 80 g (veg.)Rccreational Consump!ion of locally 54 g 350 30 70 ..

caught fishSuurct': U.S. EPA (1991).

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Factor Potencial(Cancergenos)

Incrementodel riesgo de cncerFactor Potencial=

Ingestincrnica diaria (CD1)

Incremento iesgo cncer=CDI x Factor PotencialDosis media diaria (mgid)CD (mg/kg d) =

Peso kg)TABLE4.9 Toxicity data (or se!ectedpotencialcarcinogens

Potency actor Potency actororal route inhalation routeCht:rnical Category (rng'kg.day)-' (rng./kg-day)-rAr:;enic A 1.75 5081:nzcne A 2.9 X 10-: 2.9 x 10-28enzol(a)p)TCne 82 11.5 6.11Cadrniurn B1 - 6.1l.:arbonetrachloridc: B2 0.13 -Chloroform 82 6.1X 10-.1 8.1 X 10-2Chromiurn I A - 41DDT 82 0.34 -1.1-Dichloroethylcnc: C 0.58 1.16

~ Dieldrin 82 30 -) Heptachlor B2 3.4 -Hexachloroethane C 1.4x 10-2 -\1ethylene hloride 82 7.5 x 10-3Nickelandcornpounds A-Po1ychlorinatediphenyls PCBs) B2 7.7 -2,3.7.8-TCDD (dioxin) B2 1.56 x 10~ . -Tetrachloroethylene 82 5.1 X 10-21.1.1-Trichloroethane1.1,l-TCA) D - -Trichloroethylene (TCE) B2 1.1 X 10-2 1.3 X 10-2Vinyl chloride A 2.3 0.295

Sourct: U.s. EPA http://www.epa.gov/iris.


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,'BIOCONCENTRACIONUna ruta importantede exposicina compuestos eligrososes elconsumode pescadocontaminado

,.Concentoen peces = (Concent. en agua) x(Factor bioconcentracin)

TABlE 4.12 Bioconcentration Factors BCFs) for a SelectedList of Chemicals.Chemical Bioconcentration Factor (Ukg)Aldrin 28Arsenic and compounds 44Benzene 5.2Cadmium and compounds 81Carbon tetrachloride 19Chlordane 14.000Chlorofom1 3.75Chromium 111, I, and compounds 16Copper 200DDE 51,(XX)DDT 54,

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