Direct ContactRisk Assessment

Direct ContactRisk Assessment

Jim WalshAvatar Environmental

October 23, 2003

Jim WalshAvatar Environmental

October 23, 2003

Housatonic River – Rest of RiverHousatonic River – Rest of River

Direct Contact ChallengeDirect Contact Challenge• Over 100 miles of river and associated soils

and sediments• Hundreds of properties and exposure areas• Degree and distribution of PCBs unknown• Incidental ingestion and dermal absorption

(soil, sediment, and surface water)• Inhalation of ambient air• Focus project resources

• Over 100 miles of river and associated soils and sediments

• Hundreds of properties and exposure areas• Degree and distribution of PCBs unknown• Incidental ingestion and dermal absorption

(soil, sediment, and surface water)• Inhalation of ambient air• Focus project resources

Phased ApproachMedia ScreeningPhased ApproachMedia Screening

• Air• Air• Surface Water• Soil/Sediment

Phase 1Phase 2

• Surface Water• Soil/Sediment

Phase 1Phase 2

AirAir• Historical Data • Air Sampling Program

– RFI Report- All Nondetects (DL < 1E-06 risk level)

• Eliminated from further evaluation

• Historical Data • Air Sampling Program

– RFI Report- All Nondetects (DL < 1E-06 risk level)

• Eliminated from further evaluation

Air (con’t)Air (con’t)• Supporting Information

Recent Upper Reach SamplingIndoor Air Sampling

• Supporting InformationRecent Upper Reach SamplingIndoor Air Sampling

Surface WaterSurface Water• No potable use of water• Swimming/Wading

Scenario• Site-specific SRBCs –

ingestion while swimming• Six locations in Reaches

5, 6, and 7• Maximum Concentrations

less than SRBCs• Eliminated from further

evaluation

• No potable use of water• Swimming/Wading

Scenario• Site-specific SRBCs –

ingestion while swimming• Six locations in Reaches

5, 6, and 7• Maximum Concentrations

less than SRBCs• Eliminated from further

evaluation

Phase 1 Exposure Area Screening Approach – Soil/SedimentPhase 1 Exposure Area Screening Approach – Soil/Sediment

Scenario and Medium Identification

Media•Floodplain soil•Riverbank soil•Sediment

Exposure Scenarios•Residential•Recreational•Agricultural•Commercial/Industrial

Comparison of maximum detectedmedium PCB level to medium-specific SRBC

ExceedsSRBC?Yes No

No further evaluation necessary

HHRAYes

NoExceedsSRBC?

Comparison of PCB EPC tomedium-specific SRBC

Important ConceptsImportant Concepts• Exposure Areas• SRBCs• Data Collection

• Exposure Areas• SRBCs• Data Collection

Exposure Area ConceptExposure Area Concept

• Properties• Groups of Properties • Reach • River Characteristics• State

• Properties• Groups of Properties • Reach • River Characteristics• State

Exposure AreasExposure AreasSoil

Individual properties (Reaches 5 & 6)Groups of properties (Reaches 7 & 8)Reach 9State (Connecticut, Reaches 10-16)

SedimentStretches of river (Reaches 5 & 6)Free-flowing vs. impoundments (Reaches 7 & 8)Reach 9State (Connecticut, Reaches 10-16)

SoilIndividual properties (Reaches 5 & 6)Groups of properties (Reaches 7 & 8)Reach 9State (Connecticut, Reaches 10-16)

SedimentStretches of river (Reaches 5 & 6)Free-flowing vs. impoundments (Reaches 7 & 8)Reach 9State (Connecticut, Reaches 10-16)

Phase 1 ScreeningRisk-Based Concentrations

Phase 1 ScreeningRisk-Based Concentrations

2 mg/kgAgricultural

Sediment

Soil

5 mg/kg – high contact7 mg/kg – low contact

Recreational

20 mg/kgCommercial/industrial

3 mg/kg – high contact5 mg/kg – low contact

Sediment exposure

2 mg/kg – high contact5 mg/kg – low contact

Residential

High Contact ResidentialHigh Contact Residential

• Refers to current residential properties only• Defined in CD as actual/potential lawn• SRBC = 2 mg/kg• If any concentration > 2 mg/kg, transfer to

GE for more in-depth analysis

• Refers to current residential properties only• Defined in CD as actual/potential lawn• SRBC = 2 mg/kg• If any concentration > 2 mg/kg, transfer to

GE for more in-depth analysis

Low Contact Residential and High Contact RecreationalLow Contact Residential and High Contact Recreational

0.000001Conversion factor (CF), (kg/mg)

252 (see next slide)Age-adjusted soil contact factor (SFS), (mg-year/kg-day)

TR x AT/(EF x SFS x ABS x SF x CF)Dermal Contact SRBC (mg/kg) =

2.0Slope factor (SF), (mg/kg-day)-10.14Dermal absorption factor (ABS)

114 (see next slide)Age-adjusted soil ingestion factor (IFS), (mg-year/kg-day)

84Exposure frequency (EF), (days/year)25,550Averaging time (AT), (days)

5E-06Target risk (TR)

TR x AT/(EF x IFS x SF x CF)Ingestion SRBC (mg/kg) =

Low Contact Residential and High Contact RecreationalLow Contact Residential and High Contact Recreational

0.2 (AFc), 0.01 (AFa)Soil-to-skin adherence factor (AF), (mg/cm2)

15 (BWc), 70 (BWa)Body weight (BW), (kg)

200 (IRc), 100 (IRa)Ingestion rate (IR), (mg/day)

6 (EDc), 24 (EDa)Exposure duration (ED), (years)

252Age-adjusted soil contact factor (SFS), (mg-year/kg-day)

114Age-adjusted soil ingestion factor (IFS), (mg-year/kg-day)

(EDc x AFc x SAc/BWc)+(EDa x AFa x SAa/BWa)SFS (mg-year/kg-day) =

2,900 (SAc), 5,700 (SAa)Exposed skin surface area (SA), (cm2)

(EDc x IRc/BWc)+(EDa x IRa/BWa)IFS (mg-year/kg-day) =

SRBC IntegrationSRBC Integration

SRBCSRBCintint = [(SRBC= [(SRBCinging))--11 + (SRBC+ (SRBCdcdc))--11]]--11

Medium-specific SRBC for dermal contact

SRBCdc =

Medium-specific SRBC for ingestion

SRBCing =

Medium-specific integrated SRBC for all pathways combined

SRBCint =Where:

Data CollectionData Collection• Iterative Process

- Transect sampling- Other sampling programs- HHRA sampling

• Focus- Likelihood of Exposure- Degree of Contamination- Filling of Data Gaps

• Iterative Process- Transect sampling- Other sampling programs- HHRA sampling

• Focus- Likelihood of Exposure- Degree of Contamination- Filling of Data Gaps

Reaches 5 and 6 Screening ResultsReaches 5 and 6 Screening Results

Woods Pond

New Lenox Road

Confluence

Reaches 7 and 8 Screening ResultsReaches 7 and 8 Screening Results

MassachusettsTurnpike

Woods Pond

Stockbridge

Reaches 7 and 8 Screening ResultsReaches 7 and 8 Screening Results

Rising Pond

Stockbridge

Reach 9 Screening ResultsReach 9 Screening Results

• Rising Pond Dam to CT Border (25 miles)• Rising Pond Dam to CT Border (25 miles)

0.3510.290.161 – 0.67612/60Sediment

0.7590.510.258 – 1.29/12Riverbank Soil

0.5050.4990.26 – 6.3292/205Floodplain Soil

95% UpperConfidence

Limit(ppm)

Arithmetic Mean

Concentration(ppm)

Range of Detected Concentrations

(ppm)

Frequency of

DetectionMedium

Reaches 10 through 16 Screening Results

Reaches 10 through 16 Screening Results

• Connecticut Border to Derby DamSediment

Soil • Reach 9 eliminated• Minimal floodplain• Sediment eliminated

• Connecticut Border to Derby DamSediment

Soil • Reach 9 eliminated• Minimal floodplain• Sediment eliminated

0.026 – 0.474/28Sediment (0-6”)

Range of Detected Concentrations

(ppm)Frequency of

DetectionMedium

Phase 2Phase 2• Exposure-

area Specific Risk Assessments

• Exposure-area Specific Risk Assessments

Phase 2 Direct ContactRisk Assessment

Phase 2 Direct ContactRisk Assessment

• Exposure area-specific risk assessments

90 soil exposure areas• 66 in Reaches 5 & 6• 24 in Reaches 7 & 88 sediment exposure areas• 3 in Reaches 5 & 6• 5 in Reaches 7 & 8

• Exposure area-specific risk assessments

90 soil exposure areas• 66 in Reaches 5 & 6• 24 in Reaches 7 & 88 sediment exposure areas• 3 in Reaches 5 & 6• 5 in Reaches 7 & 8

Phase 2 Important ConceptsPhase 2 Important Concepts

• Development of EPCs• Exposure Scenarios• Results• TEQ risk• TEQ risk

• Development of EPCs• Exposure Scenarios• Results

Exposure Point ConcentrationsExposure Point Concentrations

• Reaches 5 and 6 SoilHall’s bootstrapSpatial WeightingAccessibility categoriesUse weighting

• Reaches 5 and 6 SoilHall’s bootstrapSpatial WeightingAccessibility categoriesUse weighting

Accessibility CategoriesAccessibility Categories

• Walkable – easily accessible wearing sneakers or boots. (1.0)

• Difficult to Access – wet with soft muck during part of the year; dense vegetation throughout the year. (0.5)

• Wadable – waters less than 3 feet deep for some part of the year; fairly open when dry. (0.5)

• Boatable – accessible by boat, but too deep to wade. (0)

• Walkable – easily accessible wearing sneakers or boots. (1.0)

• Difficult to Access – wet with soft muck during part of the year; dense vegetation throughout the year. (0.5)

• Wadable – waters less than 3 feet deep for some part of the year; fairly open when dry. (0.5)

• Boatable – accessible by boat, but too deep to wade. (0)

Process for Identifying Exposure ScenariosProcess for Identifying Exposure Scenarios

• Area residents- Sportsmen's clubs- Environmental groups- Educators- Officials

• Field sampling team• State Agencies• HHRA team

• Area residents- Sportsmen's clubs- Environmental groups- Educators- Officials

• Field sampling team• State Agencies• HHRA team

Exposure ScenariosExposure Scenarios

Land Uses (current and future)• Residential• Recreational• Agricultural• Commercial/industrial

Land Uses (current and future)• Residential• Recreational• Agricultural• Commercial/industrial

Recreational ActivitiesRecreational Activities

CanoeingCanoeing

Boat launchingBoat launching

Recreational ActivitiesRecreational Activities

Walking,Walking,HikingHiking

Recreational ActivitiesRecreational Activities

HuntingHunting

FishingFishing

Recreational ActivitiesRecreational Activities

CampingCamping

Mountain bikingMountain biking

Recreational Exposure ScenariosRecreational Exposure Scenarios

• General recreation• ATV/dirt and mountain bike rider• Recreational canoeist/boater• Marathon canoeist• Angler• Waterfowl hunter• Sediment

• General recreation• ATV/dirt and mountain bike rider• Recreational canoeist/boater• Marathon canoeist• Angler• Waterfowl hunter• Sediment

General RecreationRisk CalculationGeneral RecreationRisk Calculation

Soil Ingestion Dose = CS x IR x FI x EF x ED x CF/(BW x AT)Soil Ingestion Dose = CS x IR x FI x EF x ED x CF/(BW x AT)Exposure area-specificSoil concentration (CS), (mg/kg)

25,550Averaging time (AT), (days)70Body weight (BW), (kg)0.000001Conversion factor (CF), (kg/mg)52Exposure duration (ED), (year)

90 or 30 (site-specific)Exposure frequency (EF), (days/year)

1.0Fraction ingested (FI)100Soil ingestion rate (IR), (mg/day)

Adult RME parameters for cancer effects.Adult RME parameters for cancer effects.

General RecreationRisk Calculation (con’t)General RecreationRisk Calculation (con’t)

0.14Dermal absorption factor (ABS)2Activity duration – cool months (AD2), (months)

5,700Skin surface area – warm months (SA1), (cm2)0.07Adherence factor – warm months (AF1), (mg/cm2)1,306Skin surface area – cool months (SA2), (cm2)0.15Adherence factor – cool months (AF2), (mg/cm2)5Activity duration – warm months (AD1), (months)

Exposure area-specificSoil concentration (CS), (mg/kg)

25,550Averaging time (AT), (days)70Body weight (BW), (kg)0.000001Conversion factor (CF), (kg/mg)

52Exposure duration (ED), (year)90 or 30 (site-specific)Exposure frequency (EF), (days/year)

Dermal Absorption Dose = CS x EF x ED x {[(SA1 x AF1 x AD1) + (SDermal Absorption Dose = CS x EF x ED x {[(SA1 x AF1 x AD1) + (SA2 x AF2 x A2 x AF2 x AD2)]/AD1 +AD2} x ABS x CF/(BW x AT)AD2)]/AD1 +AD2} x ABS x CF/(BW x AT)

Adult RME parameters for cancer effects.Adult RME parameters for cancer effects.

General RecreationRisk Calculation (con’t)General RecreationRisk Calculation (con’t)

Decker Canoe Launch Area

3E-053E-056E-062.01.3E-053.2E-0625.7

Total

Dermal Contact

RiskIngestion

RiskSlope Factor (mg/kg-day)-1

Dermal Contact

Dose (mg/kg-day)

Ingestion Dose

(mg/kg-day)

Exposure point concentration

(mg/kg)

Based on RME parameters for total PCBsBased on RME parameters for total PCBs

Summary of Cancer Risk Estimates from Soil Exposure

Summary of Cancer Risk Estimates from Soil Exposure

1E-09

1E-08

1E-07

1E-06

1E-05

1E-04

1E-03

1E-02

Can

cer R

isk

(log-

scal

e)

= RME

= CTE

= EPA risk range (1E-06 to 1E-04)

Residential

ATV/ Dirt and

Mountain Bike

Rider

Recreational

Canoeist

Marathon

Canoeist

Angler

Waterfowl

Hunter

Farmer

Groundskeeper

Utility Worker

General

Recreation

Summary of Hazard Indices from Soil Exposure

Summary of Hazard Indices from Soil Exposure

0.001

0.01

0.1

1

10

100

Haz

ard

Inde

x (lo

g-sc

ale)

Residential

ATV/ Dirt and

Mountain Bike

Rider

Recreational

Canoeist

Marathon

Canoeist

Angler

Waterfowl

Hunter

Farmer

Groundskeeper

Utility Worker

General

Recreation

= RME

= CTE

Summary of Cancer Risk Estimates from Sediment Exposure

Summary of Cancer Risk Estimates from Sediment Exposure

Area 8

1E-08

1E-07

1E-06

1E-05

1E-04

1E-03

1E-02

Can

cer R

isk

(log-

scal

e)

Confluence to

New Lenox Road

New Lenox Road

to Woods Pond

Woods Pond

Columbia Mill Dam

Impoundment

Eagle Mill Dam

Impoundment

Willow M

il Dam

Impoundment

Rising Pond

Glendale Dam

Impoundment

= EPA risk range (1E-06 to 1E-04)

Reach 5 Reach 6 Reach 7 Reach 8

Summary of Hazard Indices from Sediment Exposure

Summary of Hazard Indices from Sediment Exposure

0.001

0.01

0.1

1

10

100

Haz

ard

Inde

x (lo

g-sc

ale)

Confluence to

New Lenox Road

New Lenox Road

to Woods Pond

Woods Pond

Columbia Mill Dam

Impoundment

Eagle Mill Dam

Impoundment

Willow M

il Dam

Impoundment

Rising Pond

Glendale Dam

Impoundment

Reach 5 Reach 6 Reach 7 Reach 8

Approach to Calculating PCB plus TEQ riskApproach to Calculating PCB plus TEQ risk

• Congener samples – 10% of PCB samples• Developed association between PCB

concentrations and TEQ conc.• General Recreation Scenario Risk

Estimates- 1, 5, 10, 50, 100 mg/kg PCBs

• Range of TEQ risk/PCB risk (2.5 – 0.5)

• Congener samples – 10% of PCB samples• Developed association between PCB

concentrations and TEQ conc.• General Recreation Scenario Risk

Estimates- 1, 5, 10, 50, 100 mg/kg PCBs

• Range of TEQ risk/PCB risk (2.5 – 0.5)

Summary of Cancer Risk Estimates

Summary of Cancer Risk Estimates

1E-08

1E-07

1E-06

1E-05

1E-04

1E-03

Can

cer

Ris

k (lo

g-sc

ale)

= Risk from PCBs.

= Risk from PCBs and TEQ.

Residential

ATV/ Dirt and

Mountain Bike

Rider

Recreational

Canoeist

Marathon

Canoeist

Angler

Waterfowl

Hunter

Sediment

Exposure

Farmer

Groundskeeper

Utility Worker

General

Recreation

= EPA risk range (1E-06 to 1E-04)

Direct ContactRisk AssessmentHousatonic River – Rest of RiverDirect Contact ChallengePhased ApproachMedia ScreeningAirAir (con’t)Surface WaterPhase 1 Exposure Area Screening Approach – Soil/SedimentImportant ConceptsExposure Area ConceptExposure AreasPhase 1 ScreeningRisk-Based ConcentrationsHigh Contact ResidentialLow Contact Residential and High Contact RecreationalLow Contact Residential and High Contact RecreationalSRBC IntegrationData CollectionReaches 5 and 6 Screening ResultsReaches 7 and 8 Screening ResultsReaches 7 and 8 Screening ResultsReach 9 Screening ResultsReaches 10 through 16 Screening ResultsPhase 2Phase 2 Direct ContactRisk AssessmentPhase 2 Important ConceptsExposure Point ConcentrationsAccessibility CategoriesProcess for Identifying Exposure ScenariosExposure ScenariosRecreational ActivitiesRecreational ActivitiesRecreational ActivitiesRecreational ActivitiesRecreational Exposure ScenariosGeneral RecreationRisk CalculationGeneral RecreationRisk Calculation (con’t)General RecreationRisk Calculation (con’t)Summary of Cancer Risk Estimates from Soil ExposureSummary of Hazard Indices from Soil ExposureSummary of Cancer Risk Estimates from Sediment ExposureSummary of Hazard Indices from Sediment ExposureApproach to Calculating PCB plus TEQ riskSummary of Cancer Risk Estimates

barcodetext: SDMS DocID 517483barcode: *517483*