REx (Version 2.1G): Page 1 of 38

RExResidential Exposure Assessment Model

TECHNICAL GUIDE

Prepared by

infoscientific.com, Inc.

Prepared for

Organo Phosphates Case Study Group

April 2000

REx (Version 2.1G): Page 2 of 38

TABLE OF CONTENTS

Page

1.0 Introduction ………. 3

2.0 Product Use Scenarios ………. 4

3.0 Exposure Pathways & Assessment Methods ………. 5

4.0 Inputs ………. 7

5.0 Algorithms ……… 10

REx (Version 2.1G): Page 3 of 38

1.0 INTRODUCTION

REx (Residential Exposure Assessment Model) is a spreadsheetEXCEL basedexposure/dose assessment model that allows aggregating product use scenarios.REx is implemented in a user-friendly environment such that both simple deterministicand complex stochastic exposure and dose assessments can be made.

The product use scenarios in REx are those based on EPA’s Residential SOPs draftdocument. One or more (up to six) scenarios can be aggregated to estimate exposureand dose to receptors of interest. Receptors included in this version of REx are adultsand three categories of children (< 1 year, 1 year < age < 6 years, and age > 6 years).

Aggregation can be done for “day 0” during and post application scenarios.

REx (Version 2.1G): Page 4 of 38

2.0 PRODUCT USE SCENARIOS

The following scenarios are currently represented in REx:- Lawn Care- Vegetable Garden Care- Ornamental Plant Care- Tree Care- Pick Own Fruits/Vegetables- Crack & Crevice Treatment- Termite Control- Rodent Control- Pet Care- Outdoor Fogger Use- Indoor Fogger Use- Indoor Treatment- Paint/Wood Treatment- Impregnated Materials- Detergent/Handsoap Use- Swimming Pool Use- Custom

REx (Version 2.1G): Page 5 of 38

3.0 EXPOSURE PATHWAYS & ASSESSMENT METHODS

The following are the receptor-specific (adult and child groups) exposure pathwaysand the associated assessment methods included in REx. The name of the algorithmrepresenting each assessment method is provided in parenthesis alongside themethod.

ADULT

During Application

DermalUnit Exposure, Area Treated (Dermal 101)Unit Exposure, Amount of Formulation Used (Dermal 102)

InhalationUnit Exposure, Area Treated (Inhalation 101)Unit Exposure, Amount of Formulation Used (Inhalation 102)

Dermal + InhalationUnit Exposure, Area Treated (Multiple 101)Unit Exposure, Amount of Formulation Used (Multiple 102)

Post Application

DermalTransfer Coefficient (Residue) (Dermal 103)Transfer Coefficient (Area Treated) (Dermal 105)Transfer Factor (Residue) (Dermal 107)Transfer Factor (Area Treated) (Dermal 109)Fraction Transferred (Dermal 111)Flux Rate (Dermal 113)Water Concentration (Dermal 115)Film Thickness (DERMAL Model) (Dermal 117)

Ingestion: WaterWater Concentration (Ingestion 106)

InhalationIndoor Air Concentration (Inhalation 103)Outdoor Air Concentration (Inhalation 105)

REx (Version 2.1G): Page 6 of 38

CHILD

Post Application

DermalTransfer Coefficient (Residue) (Dermal 104)Transfer Coefficient (Area Treated) (Dermal 106)Transfer Factor (Residue) (Dermal 108)Transfer Factor (Area Treated) (Dermal 110)Fraction Transferred (Dermal 112)Flux Rate (Dermal 114)Water Concentration (Dermal 116)Film Thickness (DERMAL Model) (Dermal 118)

Ingestion: Granules/Pellets (Formulation)Granules/Pellets (Formulation) (Ingestion 101)

Ingestion: Grass/PlantsGrass/Plants (Ingestion 102)

Ingestion: SoilSoil (Ingestion 103)

Ingestion: Hand-To-Mouth TransferMass Balance (Ingestion 104)Fraction Transferred (Ingestion 109)EPA SOPs Method (Ingestion 110)

Ingestion: Paint ChipsPaint Chips (Ingestion 105)

Ingestion: WaterWater Concentration (Ingestion 107)

Ingestion: Flux rateFlux Rate (Ingestion 108)

InhalationIndoor Air Concentration (Inhalation 104)Outdoor Air Concentration (Inhalation 106)

REx (Version 2.1G): Page 7 of 38

4.0 INPUTS

4.1 GENERAL (scenario independent)

Exposure Clothing Penetration Fraction (Uncovered) unitlessClothing Penetration Fraction (Covered) unitlessIngestion Rate (Granules/Pellets) (Child) g/dayIngestion Rate (Grass/Plants) (Child) cm2/dayIngestion Rate (Soil) (Child) mg/dayIngestion Rate (Paint Chips) (Child) mg/dayIngestion Rate (Water) (Adult) L/hrIngestion Rate (Water) (Child) L/hrTransfer Efficiency (Hand-To-Mouth) (per Contact) (Child) unitlessFraction Transferred (Hand-To-Mouth) (Total) (Child) unitlessReference Duration day

Dose Fraction Absorbed (Dermal + Inhalation) (During Application) unitlessFraction Absorbed (Dermal) unitlessFraction Absorbed (Ingestion) unitlessFraction Absorbed (Inhalation) unitlessNOEL (Dermal) (Applied Dose) mg/kg/dayNOEL (Ingestion) (Applied Dose) mg/kg/dayNOEL (Inhalation) (Applied Dose) mg/kg/dayNOEL (Absorbed Dose) (Systemic) mg/kg/day

Human Area (Hands) (Uncovered) (Adult) cm2

Factors Area (Hands) (Covered) (Adult) cm2

Area (Upper Body) (Uncovered) (Adult) cm2

Area (Upper Body) (Covered) (Adult) cm2

Area (Lower Body) (Uncovered) (Adult) cm2

Area (Lower Body) (Covered) (Adult) cm2

Area (Feet) (Uncovered) (Adult) cm2

Area (Feet) (Covered) (Adult) cm2

Area (Hands) (Uncovered) (Child) cm2

Area (Hands) (Covered) (Child) cm2

Area (Upper Body) (Uncovered) (Child) cm2

Area (Upper Body) (Covered) (Child) cm2

Area (Lower Body) (Uncovered) (Child) cm2

Area (Lower Body) (Covered) (Child) cm2

Area (Feet) (Uncovered) (Child) cm2

Area (Feet) (Covered) (Child) cm2

Area (Total) (Adult) cm2

Area (Total) (Child) cm2

Area (Hands) (Hand-To-Mouth) (Child) cm2

Contact Frequency (Hand-To-Mouth) (Child) events/hrInhalation Rate (Adult) m3/hrInhalation Rate (Child) m3/hrBody Weight (Adult) kgBody Weight (Child) kg

REx (Version 2.1G): Page 8 of 38

4.2 SPECIFIC (scenario dependent)

Source Application (AI per Area Treated) lb ai/acreApplication (AI per Amount of Formulation Used) lb ai/galArea Treated acreAmount of Formulation as Used (By Volume) galAmount of Formulation as Used (By Weight) mgFraction AI in Formulation as Used unitlessDensity of Formulation g/cm3

Environment Air concentration (Indoor) of AI microg/m3

Dilution factor (Outdoor air) unitlessVolume of air (Outdoor, imaginary) m3

Concentration of AI in Water mg/m3

Permeability Coefficient cm/hrFlux Rate of AI through Impregnated Material mg/m2/dayFraction Transferred to Whole Body (Dermal) unitlessFraction AI available (Ingestion) unitlessTransferable Residue (Surface) (Environment/Pet) mg/cm2

Soil Density (Outdoor) g/cm3

Thickness of Effective Soil Layer cmGround Cover (Grass/Plants) g/cm2

Fraction AI Dislodgeable from Surface (Environment/Pet) unitlessFraction AI Dislodgeable from Grass/Plants unitlessFraction AI Dislodgeable from Soil unitlessFraction AI in Paint Chips unitlessFraction AI Dissipated Daily unitless

Exposure Unit Exposure (Dermal + Inhalation) (During Application) mg/lb aiUnit Exposure (Dermal) (During Application) mg/lb aiUnit Exposure (Inhalation) (During Application) mg/lb aiFilm Thickness of Formulation on Dermal Area cmTransfer Coefficient (Dermal) (Adult) cm2/hrTransfer Coefficient (Dermal) (Child: age > 6) cm2/hrTransfer Coefficient (Dermal) (Child: 16) cm2

Area Contacted with Imp Material (Child: 1

REx (Version 2.1G): Page 9 of 38

Area Mouthed with Imp Mat (Child: 16) hrExposure Duration (Impregnated Material) (Child: 1

REx (Version 2.1G): Page 10 of 38

5.0 ALGORITHMS

5.1 Exposure Pathway: Dermal

Methods:

Dermal 101Unit Exposure, Area Treated

Dermal 102Unit Exposure, Amount of Formulation Used

Dermal 103/104Transfer Coefficient (Residue)

Dermal 105/106Transfer Coefficient (Area Treated)

Dermal 107/108Transfer Factor (Residue)

Dermal 109/110Transfer Factor (Area Treated)

Dermal 111/112Fraction Transferred

Dermal 113/114Flux Rate

Dermal 115/116Water Concentration

Dermal 117/118Film Thickness (DERMAL Model)

REx (Version 2.1G): Page 11 of 38

Dermal 101

Method: Unit exposure, Area treated

Application: DuringReceptor: Adult

Inputs

Source Application (AI per Area Treated) kg ai/m2

Area Treated m2

Exposure Unit Exposure (Dermal) (During application) mg/kg aiReference Duration day

Human Factor Body Weight (Adult) kg

Calculation (ExposureAdult: mg/kg/day)

( ) ( ) ( )( ) ( )

Adult

TreatedAreaDermalAdult

WeightBodyDurationferenceRe

TreatedAreanApplicatioExposureUnitExposure

×

××=

REx (Version 2.1G): Page 12 of 38

Dermal 102

Method: Unit exposure, Amount of Formulation Used

Application: DuringReceptor: Adult

Inputs

Source Application (Amount of AI Used) kg ai/m3

Amount of Formulation Used m3

Exposure Unit Exposure (Dermal) (During Application mg/kg aiReference Duration day

Human Factor Body Weight (Adult) kg

Calculation (ExposureAdult: mg/kg/day)

( ) ( ) ( )( ) ( )

Adult

UsedFormAmtDermalAdult

WeightBodyDurationferenceRe

UsedFormofAmountnApplicatioExposureUnitExposure

×

××=

REx (Version 2.1G): Page 13 of 38

Dermal 103/104

Method: Transfer Coefficient (Residue)

Application: PostReceptor: Adult / Child

Inputs

Environment Transferable Residue (Surface) (Environment/Pet) mg/cm2

Fraction Dissipated Daily unitlessExposure Transfer Coefficient (Adult/Child) cm2/hr

Fraction Transferred to Hand (Dermal) (Child) unitlesst (= Post Application Day) dayExposure Duration (Adult/Child) hr/day

Human Factor Body Weight (Adult/Child) kg

Calculation (Transferable Residue: mg/cm2; ExposureAdult/Child: mg/kg/day; ExposureHand,Child: mg/day)

( ) ( )ttt DailyDissipatedFractionsidueReleTransferabsidueReleTransferab −×= = 10

( ) ( ) ( )( )

Child/Adult

Child/AdultChild/AdulttChild/Adult WeightBody

DurationExptCoefficienferTranssidueReTransExposure

××=

( ) ( ) ( ) ( )ChildChild,HandChildtChild,Hand DurExpTransFracCoeffTranssReTransExposure ×××=

REx (Version 2.1G): Page 14 of 38

Dermal 105/106

Method: Transfer Coefficient (Area Treated)

Application: PostReceptor: Adult / Child

Inputs

Source Application (AI per Area Treated) kg ai/m2

Environment Fraction AI Dislodgeable in Surface unitlessFraction AI Dissipated Daily unitless

Exposure Transfer Coefficient (Adult/Child) cm2/hrt (= Post Application Day) dayFraction Transferred to Hand (Dermal) (Child) unitlessExposure Duration (Adult/Child) hr/day

Human Factor Body Weight (Adult/Child) kg

Calculation (Transferable Residue: mg/cm2, ExposureAdult/Child: mg/kg/day; ExposureHand,Child: mg/day)

( ) ( ) ( ) 1001 ×−××= tTreatedAreat DailyDissFracDislodgeAIFracnApplicatiosidueReTrans

( ) ( ) ( )( )

Child/Adult

Child/AdultChild/AdulttChild/Adult WeightBody

DurationExptCoefficienferTranssidueReTransExposure

××=

( ) ( ) ( ) ( )ChildChild,HandChildtChild,Hand DurExpTransFracCoeffTranssReTransExposure ×××=

REx (Version 2.1G): Page 15 of 38

Dermal 107/108

Method: Transfer Factor (Residue)

Application: PostReceptor: Adult / Child

Inputs

Environment Transferable Residue (Surface) (Environment/Pet) mg/cm2

Fraction Dissipated Daily unitlessExposure Transfer Factor – Hands (Uncovered) (Adult/Child) unitless

Transfer Factor – Hands (Covered) (Adult/Child) unitlessTransfer Factor – Upper Body (Uncovered) (Adult/Child) unitlessTransfer Factor – Upper Body (Covered) (Adult/Child) unitlessTransfer Factor – Lower Body (Uncovered) (Adult/Child) unitlessTransfer Factor – Lower Body (Covered) (Adult/Child) unitlessTransfer Factor – Feet (Uncovered) (Adult/Child) unitlessTransfer Factor – Feet (Covered) (Adult/Child) unitlessClothing Penetration Fraction (Uncovered) (Adult/Child) unitlessClothing Penetration Fraction (Covered) (Adult/Child) unitlessReference Duration day

Human Factor Surface Area (Hands) (Uncovered) (Adult/Child) cm2

Surface Area (Hands) (Covered) (Adult/Child) cm2

Surface Area (Upper Body) (Uncovered) (Adult/Child) cm2

Surface Area (Upper Body) (Covered) (Adult/Child) cm2

Surface Area (Lower Body) (Uncovered) (Adult/Child) cm2

Surface Area (Lower Body) (Covered) (Adult/Child) cm2

Surface Area (Feet) (Uncovered) (Adult/Child) cm2

Surface Area (Feet) (Covered) (Adult/Child) cm2

Body Weight (Adult/Child) kg

Calculation (Transferable Residue: mg/cm2; ExposureAdult/Child: mg/kg/day; ExposureHand,Child: mg/day)

( ) ( )ttt DailyDissipatedFractionsidueReleTransferabsidueReleTransferab −×= = 10

( ) ( ) ( ){ } ( )( ) ( )

Child/Adult

tChild/AdultChild/Adult

WeightBodyDurationferenceRe

sReTransFactorPenClothAreaSurfFactorTransExposure

××××

= ∑

- summation across all body parts (uncovered and covered)

( ) ( ) ( ){ } ( )( )DurationferenceRe

sReTransFactorPenClothAreaSurfFactTransExposure tChildChild,Hand

∑ ×××=- summation across hands (uncovered and covered)

REx (Version 2.1G): Page 16 of 38

Dermal 109/110

Method: Transfer Factor (Area Treated)

Application: PostReceptor: Adult / Child

Inputs

Source Application (AI per Area Treated) kg ai/m2

Environment Fraction AI Dislodgeable in Surface unitlessFraction AI Dissipated Daily unitless

Exposure Transfer Factor – Hands (Uncovered) (Adult/Child) unitlessTransfer Factor – Hands (Covered) (Adult/Child) unitlessTransfer Factor – Upper Body (Uncovered) (Adult/Child) unitlessTransfer Factor – Upper Body (Covered) (Adult/Child) unitlessTransfer Factor – Lower Body (Uncovered) (Adult/Child) unitlessTransfer Factor – Lower Body (Covered) (Adult/Child) unitlessTransfer Factor – Feet (Uncovered) (Adult/Child) unitlessTransfer Factor – Feet (Covered) (Adult/Child) unitlessClothing Penetration Fraction (Uncovered) unitlessClothing Penetration Fraction (Covered) unitlesst (= Post Application Day) dayReference Duration day

Human Factor Surface Area (Hands) (Uncovered) (Adult/Child) cm2

Surface Area (Hands) (Covered) (Adult/Child) cm2

Surface Area (Upper Body) (Uncovered) (Adult/Child) cm2

Surface Area (Upper Body) (Covered) (Adult/Child) cm2

Surface Area (Lower Body) (Uncovered) (Adult/Child) cm2

Surface Area (Lower Body) (Covered) (Adult/Child) cm2

Surface Area (Feet) (Uncovered) (Adult/Child) cm2

Surface Area (Feet) (Covered) (Adult/Child) cm2

Body Weight (Adult/Child) kg

Calculation (Transferable Residue: mg/cm2, ExposureAdult/Child: mg/kg/day; ExposureHand,Child: mg/day)

( ) ( ) ( ) 1001 ×−××= tTreatedAreat DailyDissFracDislodgeAIFracnApplicatiosidueReTrans

( ) ( ) ( ){ } ( )( ) ( )

Child/Adult

tChild/AdultChild/Adult

WeightBodyDurationferenceRe

sReTransFactorPenClothAreaSurfFactorTransExposure

××××

= ∑

- summation across all body parts (uncovered and covered)

( ) ( ) ( ){ } ( )( )DurationferenceRe

sReTransFactorPenClothAreaSurfFactTransExposure tChildChild,Hand

∑ ×××=- summation across hands (uncovered and covered)

REx (Version 2.1G): Page 17 of 38

Dermal 111/112

Method: Fraction Transferred

Application: PostReceptor: Adult / Child

Inputs

Source Amount of Formulation as Used (By Weight) mgFraction AI in Formulation unitless

Environment Fraction AI Dislodgeable on Surface (Environment/Pet) unitlessFraction AI Dissipated Daily unitless

Exposure Fraction Transferred to Whole Body (Dermal) cm2/hrFraction Transferred to Hand (Dermal) (Child) unitlesst (= Post Application Day) dayReference Duration day

Human Factor Body Weight (Adult/Child) kg

Calculations (Transferable Residue: mg; ExposureAdult/Child: mg/kg/day; ExposureHand,Child: mg/day)

( ) ( ) ( ) ( )tt DailyDissFracDislodgeAIFracFormAIFracUsedFormAmtsidueReTrans −×××= 1

( ) ( )( )

Child/Adult

Child/Adult,BodyWholet

Child/AdultWeightBody

dTransferreFractionsidueReleTransferabExposure

×=

( ) ( ) Child,HandtChild,Hand dTransferreFractionsidueReleTransferabExposure ×=

REx (Version 2.1G): Page 18 of 38

Dermal 113/114

Method: Flux Rate

Application: PostReceptor: Adult / Child

Inputs

Environment Flux Rate of AI through Impregnated Material mg/m2/dayFraction Dissipated Daily unitless

Exposure Exposure Duration (To Impregnated Material) (Adult/Child) hrFraction Transferred to Hand (Dermal) unitlesst (= Post Application Day) dayReference Duration day

Human Factor Surface Area Contact with Impregnated Material (Ad/ Ch) cm2

Body Weight (Adult/Child) kg

Calculations (ExposureAdult/Child: mg/kg/day; ExposureHand,Child: mg/day)

( ) ( )tChild/Adult DailyDissFracAIRateFluxExposure −×= 1( ) ( )

( ) ( ) ( )2410000××××

×Child/Adult

Child/AdultChild/Adult,Contact

WeightBodyDurationferenceRe

DurationExposureAreaSurface

( ) ( )tChild,Hand DailyDissipatedFractionAIRateFluxExposure −×= 1( ) ( ) ( )

( ) ( )2410000××××

×DurationferenceRe

DurationExposuredTransferreFractionAreaSurfaceChildChild,HandChild,Contact

REx (Version 2.1G): Page 19 of 38

Dermal 115/116

Method: Water Concentration

Application: PostReceptor: Adult / Child

Inputs

Environment Concentration of AI Pool Water mg/m3

Fraction Dissipated Daily unitlessPermeability Coefficient cm/hr

Exposure Exposure Duration (Adult/Child) hrt (= Post Application Day) dayReference Duration day

Human Factor Surface Area (Whole Body) (Adult/Child) cm2

Body Weight (Adult/Child) kg

Calculations (ExposureAdult/Child: mg/kg/day)

( ) ( ) ( )CoefftyPermeabiliDailyDissipatedFractionWaterAIConcExposure tChild/Adult ×−×= 1( ) ( )( ) ( ) ( )1000000××

××

Child/Adult

Child/AdultChild/Adult,Contact

WeightBodyDurationferenceRe

DurationExposureAreaSurface

REx (Version 2.1G): Page 20 of 38

Dermal 117/118

Method: Film Thickness (DERMAL Model)

Application: PostReceptor: Adult / Child

Inputs

Environment Density of Formulation mg/cm3

Fraction of AI in Formulation unitlessExposure Film thickness of Formulation on Dermal Area cm

Fraction Transferred to Hand (Dermal) (Child) unitlessReference Duration day

Human Factor Surface Area (Exposed to Formulation) (Adult/Child) cm2

Body Weight (Adult/Child) kg

Calculations (ExposureAdult/Child: mg/kg/day; ExposureHand,Child: mg/day)

( ) ( ) ( ) ( )( ) ( )

Child/Adult

Child/Adult,Exposed

Child/AdultWeightBodyDurationferenceRe

AreaSurfThickFilmFormAIFracFormDensityExposure

×

×××=

( ) ( ) ( )ThicknessFilmnFormulatioAIFractionnFormulatioDensityExposure Child,Hand ××=( ) ( )

( )DurationferenceRedTransferreFractionAreaSurface

Child,HandChild,Exposed×

×

REx (Version 2.1G): Page 21 of 38

5.2 Exposure Pathway: Ingestion

Methods:

Ingestion 101Granules/Pellets (Formulation)

Ingestion 102Grass/Plants

Ingestion 103Soil

Ingestion 104Hand-To-Mouth Transfer: Mass Balance

Ingestion 105Paint Chips

Ingestion 106/107Water Concentration (Swimming Pool)

Ingestion 108Flux Rate

Ingestion 109Hand-To-Mouth Transfer: Fraction Transferred

Ingestion 110Hand-To-Mouth Transfer: EPA SOP

REx (Version 2.1G): Page 22 of 38

Ingestion 101

Method: Granules/Pellets (Formulation)

Application: PostReceptor: Child

Inputs

Source Fraction AI in Formulation as Used unitlessExposure Ingestion Rate (Granules/Pellets) (Child) mg/dayHuman Factor Body Weight (Child) kg

Calculation (ExposureChild: mg/kg/day)

( ) ( )( )

Child

Child,Pellets/GranulesChild

WeightBody

Pellets/GranulesinAIFractionRateIngestionExposure

×=

REx (Version 2.1G): Page 23 of 38

Ingestion 102

Method: Grass/Plants

Application: PostReceptor: Child

Inputs

Source Application (AI per Area treated) kg ai/m2

Environment Ground Cover (Grass/Plants) g/cm2

Fraction AI Dislodgeable from Grass/Plants unitlessFraction AI Dissipated Daily unitless

Exposure Ingestion Rate (Grass/Plants) (Child) mg/dayt (= Post Application Day) day

Human Factor Body Weight (Child) kg

Calculation (ExposureChild: mg/kg/day)

( ) ( ) ( )( )CoverGround

DailyDissFracPlants/GrassAIFracnApplicatiosidueRe

tTreatedArea

Plants/Grass

−××=

1

( ) ( )( )

Child

Child,Plants/GrassPlants/GrassChild

WeightBody

RateIngestionsidueReExposure

×=

REx (Version 2.1G): Page 24 of 38

Ingestion 103

Method: Direct: Soil

Application: PostReceptor: Child

Inputs

Source Application (Area Treated) kg ai/m2

Environment Soil Density (Outdoor) g/cm3

Thickness of Effective Soil Layer cmFraction AI Dislodgeable from Soil unitlessFraction AI Dissipated Daily unitless

Exposure Ingestion Rate (Soil) (Child) mg/dayt (= Post Application Day) day

Human Factor Body Weight (Child) kg

Calculation (ExposureChild: mg/kg/day)

( ) ( ) ( )( ) ( )LayerSoilThicknessDensitySoil

DailyDissipatedFractionSoilAIFractionnApplicatiosidueRe

tTreatedArea

Soil ×

−××=

1

( ) ( )( )

Child

Child,SoilSoilChild

WeightBody

RateIngestionsidueReExposure

×=

REx (Version 2.1G): Page 25 of 38

Ingestion 104

Method: Hand-To-Mouth Transfer (Mass Balance)

Application: PostReceptor: Child

Inputs

Exposure Hand Dermal Exposure (Child) mg/dayContact Frequency (Hand-To-Mouth) (Child) events/hrTransfer Efficiency (Hand-To-Mouth) (per Contact) (Child) unitlessExposure Duration (Hand-To-Mouth) (Child) hr

Human Factor Body Weight (Child) kg

Calculation (ExposureChild: mg/kg/day)

( ) ( )[ ]( ) ( )[ ]

∑×

=

−−− −×=

DurationExpFreqContact

n

nMouthToHand EffTransferEffTransferFactorTransfer

1

11

( ) ( )( )

Child

MouthToHandChild),Dermal(Hand

ChildWeightBody

FactorTransferExposureExposure −−

×=

REx (Version 2.1G): Page 26 of 38

Ingestion 105

Method: Paint Chips

Application: PostReceptor: Child

Inputs

Source Fraction AI in Paint Chips unitlessFraction AI (in Paint Chips) available for ingestion unitless

Exposure Ingestion Rate (Paint Chips) (Child) mg/dayHuman Factor Body Weight (Child) kg

Calculation (ExposureChild: mg/kg/day)

( ) ( ) ( )( )

Child

Child,ChipsintPa

ChildWeightBody

AvailableAIFracChipsintPainAIFracRateIngestionExposure

××=

REx (Version 2.1G): Page 27 of 38

Ingestion 106/107

Method: Water Concentration (Swimming Pool)

Application: PostReceptor: Adult / Child

Inputs

Source Water Concentration (Swimming Pool) mg ai/m3

Exposure Ingestion Rate (Pool Water) (Adult/Child) m3/hrExposure Duration (in Pool) (Adult/Child) hrReference Duration day

Human Factor Body Weight (Adult/Child) kg

Calculation (ExposureChild: mg/kg/day)

( ) ( ) ( )( ) ( )

Child/Adult

Child/AdultChild/Adult,WaterPoolPoolgminSwimChild/Adult

WeightBodyDurationferenceRe

DurExpRateIngConcWaterExposure

×

××=

REx (Version 2.1G): Page 28 of 38

Ingestion 108

Method: Flux Rate

Application: PostReceptor: Child

Inputs

Source Flux Rate of AI mg/cm2/dayExposure Surface Area (Impregnated Material) Mouthed (Child) cm2

Human Factor Body Weight (Child) kg

Calculation (ExposureChild: mg/kg/day)

( ) ( )( )

Child

MouthedChild WeightBody

MaterialpregnatedImAreaSurfaceAIRateFluxExposure

×=

REx (Version 2.1G): Page 29 of 38

Ingestion 109

Method: Hand-To-Mouth Transfer (Fraction Transferred)

Application: PostReceptor: Child

Inputs

Exposure Hand Exposure (Dermal) (Child) mg/dayFraction Transferred (Hand-To-Mouth) (Based on TotalContacts Per Day) (Child)

unitless

Human Factor Body Weight (Child) kg

Calculation (ExposureChild: mg/kg/day)

( ) ( )( )

Child

MouthToHandChild),Dermal(Hand

ChildWeightBody

dTransferreFractionExposureExposure −−

×=

REx (Version 2.1G): Page 30 of 38

Ingestion 110

Method: Hand-To-Mouth Transfer (EPA SOP)

Application: PostReceptor: Child

Inputs

Source Application (Area Treated) kg ai/m2

Environment Fraction AI Dislodgeable in Surface unitlessFraction AI Dissipated Daily unitless

Exposure t (= Post Application Day) dayHand-To-Mouth Contact Frequency (Child) events/hrExposure Duration (Child) hrSurface Area of Hands Mouthed (Child) cm2

Human Factor Body Weight (Child) kg

Calculation (Transferable Residue: mg/cm2, ExposureChild: mg/kg/day)

( ) ( ) ( ) 1001 ×−××= tTreatedAreat DailyDissFracDislodgeAIFracnApplicatiosidueReTrans

( ) ( ) ( ) ( )( )

Child

ChildChild,HandsChildtChild

WeightBody

DurExpMouthedAreaSurfFreqContHtoMsReTransExposure

×××=

REx (Version 2.1G): Page 31 of 38

5.3 Exposure Pathway: Inhalation

Methods:

Inhalation 101Unit Exposure, Area Treated

Inhalation 102Unit Exposure, Amount of Formulation Used

Inhalation 103/104Indoor Air Concentration

Inhalation 105/106Outdoor Air Concentration

REx (Version 2.1G): Page 32 of 38

Inhalation 101

Method: Unit exposure, Area treated

Application: DuringReceptor: Adult

Inputs

Source Application (AI per Area Treated) kg ai/m2

Area Treated m2

Exposure Unit Exposure (Inhalation) (During Application mg/kg aiReference Duration day

Human Factor Body Weight (Adult) kg

Calculation (ExposureAdult: mg/kg/day)

( ) ( ) ( )( ) ( )

Adult

TreatedAreaInhalationAdult

WeightBodyDurationferenceRe

TreatedAreanApplicatioExposureUnitExposure

×

××=

REx (Version 2.1G): Page 33 of 38

Inhalation 102

Method: Unit exposure, Amount of Formulation Used

Application: DuringReceptor: Adult

Inputs

Source Application (Amount of AI in Formulation) kg ai/m3

Amount of Formulation Used m3

Exposure Unit Exposure (Inhalation) (During Application) mg/kg aiReference Duration day

Human Factor Body Weight kg

Calculation (ExposureAdult: mg/kg/day)

( ) ( ) ( )( ) ( )

Adult

UsedFormAmtInhalationAdult

WeightBodyDurationferenceRe

UsedFormofAmountnApplicatioExposureUnitExposure

×

××=

REx (Version 2.1G): Page 34 of 38

Inhalation 103/104

Method: Indoor Air Concentration

Application: PostReceptor: Adult / Child

Inputs

Environment Air concentration of AI (Indoor) µg/m3

Exposure Exposure Duration (Adult/Child) hr/dayHuman Factor Inhalation Rate (Adult/Child) m3/hr

Body Weight (Adult/Child) kg

Calculation (ExposureAdult/Child: mg/kg/day)

( ) ( ) ( )( )

Child/Adult

Child/AdultChild/AdultChild/Adult WeightBody

DurationExposureRateInhalationAIConcAirExposure

××=

REx (Version 2.1G): Page 35 of 38

Inhalation 105/106

Method: Outdoor Air Concentration

Application: PostReceptor: Adult / Child

Inputs

Source Amount of Formulation (As Used) (By Volume) m3

Fraction of AI in Formulation (As Used) unitlessDensity of Formulation mg/m3

Environment Dilution Factor (Outdoor Air) unitlessVolume (Outdoor, Imaginary) m3

Exposure Exposure Duration (Adult/Child) hr/dayHuman Factor Inhalation Rate (Adult/Child) m3/hr

Body Weight (Adult/Child) kg

Calculation (ExposureAdult/Child: mg/kg/day)

( ) ( ) ( ) ( )( )Outdoor

OutdoorOutdoor

Volume

FactorDilutionFormDensityFormAIFracFormAmtionConcentratAir

×××=

( ) ( ) ( )( )

Child/Adult

Child/AdultChild/AdultOutdoorChild/Adult WeightBody

DurationExposureRateInhalationConcAirExposure

××=

REx (Version 2.1G): Page 36 of 38

5.4 Exposure Pathway: Multiple (Dermal + Inhalation)

Methods:

Multiple (Dermal+Inhalation) 101Unit Exposure, Area Treated

Multiple (Dermal+Inhalation) 102Unit Exposure, Amount of Formulation Used

REx (Version 2.1G): Page 37 of 38

Multiple 101

Method: Unit exposure, Area treated

Application: DuringReceptor: Adult

Inputs

Source Application (AI per Area Treated) kg ai/m2

Area Treated m2

Exposure Unit Exposure (Dermal + Inhalation) (During Application) mg/kg aiReference Duration day

Human Factor Body Weight (Adult) kg

Calculation (ExposureAdult: mg/kg/day)

( ) ( ) ( )( ) ( )

Adult

TreatedAreaInhalationDermalAdult

WeightBodyDurationferenceRe

TreatedAreanApplicatioExposureUnitExposure

×

××= +

REx (Version 2.1G): Page 38 of 38

Multiple 102

Method: Unit exposure, Amount of Formulation Used

Application: DuringReceptor: Adult

Inputs

Source Application (Amount of AI in Formulation) kg ai/m3

Amount of Formulation Used m3

Exposure Unit Exposure (Dermal + Inhalation) (During Application) mg/kg aiReference Duration day

Human Factor Body Weight (Adult) kg

Calculation (ExposureAdult: mg/kg/day)

( ) ( ) ( )( ) ( )

Adult

UsedFormAmtInhalationDermalAdult

WeightBodyDurationferenceRe

UsedFormofAmountnApplicatioExposureUnitExposure

×

××= +