Appendix C Risk Calculations Western Margin of Northern Plumes

Transcription

1 Appendix C Calculations Western Margin of Northern Plumes Consolidated Human Health Assessment

2 General Parameters Air s During Irrigation (Reference: Guidelines for the Assessment and Management of Petroleum contaminated Sites in New Zealand) All Calculations NOTES: Vs = Volume of Air within Irrigation zone (m3) Chemical Parameters (H and MW) for taken from RAIS in August 2010 Q = Volumetric Flow rate of Water (L/min) 30 H (atm.m3/mol) = H' (dimensionless) / 41 Time = Duration of Irrigation (min) 60 d = Droplet diameter (cm) 0.2 t = Droplet drop time (s) 10 R = Gas Constant (atm.m3/mol/k) 8.20E-05 T = Absolute Temperature (K) 293 Ts = Sprinkler Water Temperature (K) 288 m1 = Water viscosity at 20oC (g/m.s) m2 = Water viscosity at Sprinkler Water Temperature (g/m.s) Chemical Parameters Calculations Liquid Mass Transfer Coefficient (cm/hr) Gas Phase Mass Transfer Coefficient (cm/hr) Overall Mass Transfer Coefficient (cm/hr) Adjusted Overall Mass Transfer Coefficient (cm/hr) Fraction Volatilised (mg/mg) Mass Volatilised (mg) in Soil Water (mg/l) COPC in Water (mg/l) Henry's Law (atm.m 3 /mol) Molecular Weight in Air (mg/m 3 ) Cw HL MW Kl Kg KL KL' fv Ms Cair Cwater 1,2-Dichloroethane (EDC) E E E E E E E E-02 Vinyl chloride E E E E E E E E-02 Carbon tetrachloride E E E E E E E E-03 Trichloroethene (TCE) E E E E E E E E-03 Tetrachloroethene (PCE) E E E E E E E E-03

3 Equations Uptake of Organic Chemicals into Crops from Water (Reference: Briggs et al. (1982), Travis and Arms (1988), RISC User Manual (Version 4.0, 2001)) Uptake into Root Crops Potential for Translocation to Above-Ground Crops Uptake into Above-Ground Crops where there is Potential 2 Uptake = VG RCF (logkow -1.78) logkow TSCF = exp( - ) = log Kow RCF = Uptake (1 - MC ) f K where: where: VG orrection Factor where: log Kow= log octanol/water partition coeff. (L/kg) RCF = Root Factor (mg/kg produce per mg/l) TSCF = Transpiration Stream Factor (unitless) MC = moisture content of produce (g/g) log Kow= log octanol/water partition coeff. (L/kg) log Kow= log octanol/water partition coeff. (L/kg) Koc = organic carbon partition coeff. (ml/g) Translocation of importance if TSCF>0.1 foc = fraction of organic carbon (g/g) oc oc Calculation of Uptake Factors COPC Uptake into Root Crops RCF (mg/kg produce per Uptake Factor (mg/kg mg/l) produce per mg/l water) Uptake Factor (mg/kg produce per mg/l water) log Kow (L/kg) Koc (ml/g) foc VG (unitless) TSCF Potential for uptake? MC (g/g) 1,2-Dichloroethane (EDC) E E E-01 yes E-01 Vinyl chloride E E E-01 yes E-01 Carbon tetrachloride E E E-01 yes E-02 Trichloroethene (TCE) E E E-01 yes E-01 Tetrachloroethene (PCE) E E E-01 yes E-02 s Above Ground Crops (mg/kg produce) Total Produce (19% root crops and 81% other crops) (mg/kg) COPC Soil Water (mg/l) Root Crops (mg/kg produce) 1,2-Dichloroethane (EDC) 3.1E E E E-03 Vinyl chloride 9.8E E E E-02 Carbon tetrachloride 6.2E E E E-04 Trichloroethene (TCE) 9.0E E E E-03 Tetrachloroethene (PCE) 8.9E E E E-04 Uptake into Above-Ground Crops

4 Calculation of Emissions into House with Crawl-Space Using Measured Flux Emissions Data Building Parameters Value Reference/Comments Indoor Air Model - Modified Box Model for Infinite Source LB length of building, m 12.7 Estimated size of house WB width of building, m 10 Estimated size of house HB height of building, m 2.7 Estimated typical height A area of floor of house, m Turczynowicz, 2002 Hcs height of crawl space, m 0.3 Estimated - Conservative Value Vcs volume of crawl space, m Calculated (Turczynowicz, 2002) Vd volume of dwelling space, m Calculated (Turczynowicz, 2002) Xcs air exchange rate in crawl space, (per day) Lower value from Australian Studies Xd air exchange rate in dwelling, (per day) Typical value as per Turczynowicz, 2002 Qcsd volumetric flow rate of air from crawl space to dwelling through wooden floor Typical value as per Turczynowicz, 2002 S indoor sinks (inhalation only), (m 3 /day) 35.1 Turczynowicz, 2002 Outdoor Air Model w Width of area outdoors (m) - upwind distance 25 Estimated A Area of area outdoors (m 2 ) 625 Calculated from width A Area outdoors (acres) 0.15 Conversion of area Q/C Dispersion Ratio (g/m 2 /s per kg/m 3 ) Calculated for typical climates in Aust. Calculation of Indoor Air (Turczynowicz, 2002) Chemical Volatile Degradation rate in Air Measured Emission Rate from Surface in Crawl Space within Building within Building Max Measured Emission Rate from Surface (per day) J (ug/day/m 2 ) C craw l space (ug/m 3 ) C building (ug/m 3 ) C building (mg/m 3 ) J (ug/min/m 2 ) 1,2-Dichloroethane 1.1E E E E E E-02 Dichloromethane 5.8E E E E E E+00 Carbon Tetrachloride 5.2E E E E E E-02 Trichloroethene 1.4E E E E E E-02 Tetrachloroethene 7.2E E E E E E-01 Calculation of Outdoor Air (Soil Screening Guidance 1996 and 2000) Chemical Measured Emission Rate from Surface Outside Outside ER (g/s/m 2 ) C outside (ug/m 3 ) C outside (mg/m 3 ) 1,2-Dichloroethane 7.50E E E-06 Dichloromethane 7.00E E E-04 Carbon Tetrachloride 2.83E E E-06 Trichloroethene 6.17E E E-06 Tetrachloroethene 1.30E E E-04

5 Inhalation of Volatiles (derived from Groundwater Source) Inhalation ExposureConc V a ET FI EF ED AT (mg/m 3 ) Parameters Relevant to Quantification of Exposure by Adult Residents - Western Margin Exposure Time Indoors (ET, hr/day) 20 Time spend indoors every day (as per NEPM 1999 and enhealth 2002) Exposure Time Outdoors (ET, hr/day) 4 Time spend indoors every day (as per Nap 1999 and enhealth 2002) Fraction Inhaled from Contaminated Source (FI, unitless) 1 Assume all of home above impacted soils Exposure Frequency (EF, days/yr) 337 Assume time at home each year Exposure Duration (ED, years) 54 Duration of exposure as per NEPM 1999 and USEPA 1989 Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC Background air Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Air (Ca) Inhalation Exposure Inhalation Exposure Non- Chronic Hazard - - Quotient Non (mg/m 3 ) -1 (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (unitless) (unitless) 1,2-Dichloroethane (EDC) 2.8E E E E E-7 89% -- Dichloromethane 2.0E-01 20% 1.6E E E E % Carbon tetrachloride 6.1E-03 40% 3.7E E E E % Trichloroethene (TCE) 4.3E E E E E E E-8 11% % Tetrachloroethene (PCE) 2.0E-02 10% 1.8E E E E % TOTAL 4.2E Ca oncentration in air weighted indoor and outdoor concentration

6 Exposure to Chemicals via Incidental Ingestion of Water (Extracted Groundwater) Daily Chemical Intake IW W IR W FI B EF ED (L/kg/day) BW AT Parameters Relevant to Quantification of Exposure by Adult Residents - Western Margin Ingestion Rate (Irw, L/day) 0.2 Assume 10% daily intake from backyard tap Fraction Ingested from Source 100% Assumed to be 100% Bioavailability (B) 100% Assume 100% bioavailability via ingestion of chemicals in water. Exposure Frequency (EF, days/year) 64 Assume contact with water 2 days per week in warmer 8 months Exposure Duration (ED, years) 54 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 75 ABS 2008 Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) USEPA 1989 and CSMS 1996 Non- Slope Factor TDI Background Intake (% TDI) TDI Allowable for Assessment (TDI- in Water (Cw) Daily Intake Non Non- Calculated Chronic Hazard Quotient (mg/kg-day) -1 (mg/kg/day) (mg/kg/day) (mg/l) (mg/kg/day) (mg/kg/day) (unitless) (unitless) 1,2-Dichloroethane (EDC) 1.0E E E E-7 0% -- Vinyl chloride 2.3E E E E-4 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E % Trichloroethene (TCE) 7.8E E E E E E-9 0% % Tetrachloroethene (PCE) 1.4E-02 10% 1.3E E E % TOTAL 2.0E

7 Dermal Exposure to Chemicals via Contact with Water (Extracted Groundwater) Daily Chemical Intake DW W SAw ET DP CF EF ED BW AT (L/kg/day) Parameters Relevant to Quantification of Exposure by Adult Residents - Western Margin Surface Area (Saw, cm 2 ) Whole adult body surface area, assuming that the adult gets completely we during irrigation or use of water from the backyard bore. A more realistic exposure would be to hands only (1068 cm2) (maximum assumed in Stage 2 Assessment) Exposure Time (ET, hr/day) 1 Assume contact with water for 1 hours each time GW is used Conversion Factor (CF, L/cm 3 ) 1.E-03 Conversion of units Dermal Permeability (cm/hr) Chemical-specific (as below) Exposure Frequency (EF, days/yr) 64 Assume contact with water 2 days per week in warmer 8 months Exposure Duration (ED, years) 54 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 75 ABS 2008 Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) USEPA 1989 and CSMS 1996 Non- Slope Factor TDI Background TDI Allowable for Intake (% TDI) Assessment (TDI- Dermal Permeability (DP) in Water (Cw) Daily Intake Non- Non- Calculated Chronic Hazard Quotient (mg/kg-day) -1 (mg/kg/day) (mg/kg/day) (cm/hr) (mg/l) (mg/kg/day) (mg/kg/day) (unitless) (unitless) 1,2-Dichloroethane (EDC) 1.0E E E E E-7 0% -- Vinyl chloride 2.3E E E E E-4 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E E % Trichloroethene (TCE) 7.8E E E E E E E-9 0% % Tetrachloroethene (PCE) 1.4E-02 10% 1.3E E E E % 1.8E

8 Inhalation of Volatiles (derived from Irrigation of Groundwater) Inhalation Exposure Conc V a ET FI EF ED AT (mg/m 3 ) Parameters Relevant to Quantification of Exposure by Adult Residents - Western Margin Exposure Time (ET, hr/day) 1 Assume groundwater used to irrigate for 1 hour each time Fraction Inhaled from Contaminated Source (FI, unitless) 1 All derived from impacted groundwater Exposure Frequency (EF, days/yr) 104 Assume groundwater used to irrigate 2 days per week Exposure Duration (ED, years) 54 Duration of exposure as per NEPM 1999 and USEPA 1989 Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC Background air Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Air (Ca) Inhalation Exposure Inhalation Exposure Non- Chronic Hazard - - Quotient Non (mg/m 3 ) -1 (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (unitless) (unitless) 1,2-Dichloroethane (EDC) 2.8E E E E E-8 8% -- Vinyl chloride 8.8E E E E E-7 91% -- Carbon tetrachloride 6.1E-03 40% 3.7E E E E % Trichloroethene (TCE) 4.3E E E E E E E-9 0% % Tetrachloroethene (PCE) 2.0E-02 10% 1.8E E E E % TOTAL 1.0E

9 Exposure to Chemicals via Ingestion of Home-grown Produce (Irrigated with Extracted Groundwater) Daily ChemicalIntake FV FV IR FV FH B EF ED BW AT (mg/kg/day) Parameters Relevant to Quantification of Exposure by Adult Residents - Western Margin Ingestion Rate of Fruit and Veg (IR FV kg/day) enhealth 2003 draft intake based on yr age group intake (max) Fraction Ingested that is Home-grown 35% Assume 35% of produce consumed each year is home-grown Bioavailability (B) 100% Assume 100% bioavailability Exposure Frequency (EF, days/year) 337 Assume time at home each year Exposure Duration (ED, years) 54 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 75 ABS 2008 Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) USEPA 1989 and CSMS 1996 Non- Slope Factor TDI Background Intake (% TDI) TDI Allowable for Assessment (TDI- in Produce (C FV ) Daily Intake Non Non- Calculated Chronic Hazard Quotient (mg/kg-day) -1 (mg/kg/day) (mg/kg/day) (mg/kg) (mg/kg/day) (mg/kg/day) (unitless) (unitless) 1,2-Dichloroethane (EDC) 1.0E E E E-7 0% -- Vinyl chloride 2.3E E E E-5 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E % Trichloroethene (TCE) 7.8E E E E E E-9 0% % Tetrachloroethene (PCE) 1.4E-02 10% 1.3E E E % TOTAL 4.2E

10 Inhalation of Volatiles (derived from Groundwater Source) Inhalation ExposureConc V a ET FI EF ED AT (mg/m 3 ) Parameters Relevant to Quantification of Exposure by Older Children Residents - Western Margin Exposure Time Indoors (ET, hr/day) 20 Time spend indoors every day (as per NEPM 1999 and enhealth 2002) Exposure Time Outdoors (ET, hr/day) 4 Time spend indoors every day (as per Nap 1999 and enhealth 2002) Fraction Inhaled from Contaminated Source (FI, unitless) 1 Assume all of home above impacted soils Exposure Frequency (EF, days/yr) 337 Assume time at home each year Exposure Duration (ED, years) 10 Duration of exposure as per NEPM 1999 and USEPA 1989 Age Dependant Adjustment Factor (ADAF) - where relevant 3 Relevant for children aged 2 to <16 years as per USEPA 2005 Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC Background air Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Air (Ca) Inhalation Exposure Inhalation Exposure Non- Chronic Hazard - - Quotient Non (mg/m 3 ) -1 (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (unitless) (unitless) 1,2-Dichloroethane (EDC) 2.8E E E E E-8 73% -- Dichloromethane 2.0E-01 20% 1.6E E E E % Carbon tetrachloride 6.1E-03 40% 3.7E E E E % Trichloroethene (TCE) 4.3E E E E E E E-8 27% % Tetrachloroethene (PCE) 2.0E-02 10% 1.8E E E E % TOTAL 9.4E Ca oncentration in air weighted indoor and outdoor concentration Includes consideration of early life susceptibility for non-threshold calculation

11 Exposure to Chemicals via Incidental Ingestion of Water (Extracted Groundwater) Daily Chemical Intake IW W IR W FI B EF ED (L/kg/day) BW AT Parameters Relevant to Quantification of Exposure by Older Children Residents - Western Margin Ingestion Rate (Irw, L/day) 0.2 Assume 10% daily intake from backyard tap Fraction Ingested from Source 100% Assumed to be 100% Bioavailability (B) 100% Assume 100% bioavailability via ingestion of chemicals in water. Exposure Frequency (EF, days/year) 64 Assume contact with water 2 days per week in warmer 8 months Exposure Duration (ED, years) 10 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 34.5 As per USEPA 1999 Age Dependant Adjustment Factor (ADAF) - where relev 3 Relevant for children aged 2 to <16 years as per USEPA 2005 Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) 3650 USEPA 1989 and CSMS 1996 Non- Slope Factor TDI Background Intake (% TDI) TDI Allowable for Assessment (TDI- in Water (Cw) Daily Intake Non Non- Calculated Chronic Hazard Quotient (mg/kg-day) -1 (mg/kg/day) (mg/kg/day) (mg/l) (mg/kg/day) (mg/kg/day) (unitless) (unitless) 1,2-Dichloroethane (EDC) 1.0E E E E-7 0% -- Vinyl chloride 2.3E E E E-5 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E % Trichloroethene (TCE) 7.8E E E E E E-9 0% % Tetrachloroethene (PCE) 1.4E-02 10% 1.3E E E % TOTAL 8.0E Includes consideration of early life susceptibility for non-threshold calculation

12 Dermal Exposure to Chemicals via Contact with Water (Extracted Groundwater) Daily Chemical Intake DW W SAw ET DP CF EF ED BW AT (L/kg/day) Parameters Relevant to Quantification of Exposure by Older Children Residents - Western Margin Surface Area (Saw, cm 2 ) Whole body gets wet each time GW is used, value adopted for male child aged years (90th percentile) (USEPA 1997) Exposure Time (ET, hr/day) 1 Assume contact with water for 1 hours each time GW is used Conversion Factor (CF, L/cm 3 ) 1.E-03 Conversion of units Dermal Permeability (cm/hr) Chemical-specific (as below) Exposure Frequency (EF, days/yr) 64 Assume contact with water 2 days per week in warmer 8 months Exposure Duration (ED, years) 10 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 34.5 As per USEPA 1997 Age Dependant Adjustment Factor (ADAF) - wher 3 Relevant for children aged 2 to <16 years as per USEPA 2005 Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) 3650 USEPA 1989 and CSMS 1996 Non- Slope Factor TDI Background TDI Allowable for Intake (% TDI) Assessment (TDI- Dermal Permeability (DP) in Water (Cw) Daily Intake Non- Non- Calculated Chronic Hazard Quotient (mg/kg-day) -1 (mg/kg/day) (mg/kg/day) (cm/hr) (mg/l) (mg/kg/day) (mg/kg/day) (unitless) (unitless) 1,2-Dichloroethane (EDC) 1.0E E E E E-8 0% -- Vinyl chloride 2.3E E E E E-5 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E E % Trichloroethene (TCE) 7.8E E E E E E E-9 0% % Tetrachloroethene (PCE) 1.4E-02 10% 1.3E E E E % 5.1E Includes consideration of early life susceptibility for non-threshold calculation

13 Inhalation of Volatiles (derived from Irrigation of Groundwater) Inhalation Exposure Conc V a ET FI EF ED AT (mg/m 3 ) Parameters Relevant to Quantification of Exposure by Older Children Residents - Western Margin Exposure Time (ET, hr/day) 1 Assume groundwater used to irrigate for 1 hour each time Fraction Inhaled from Contaminated Source (FI, unitless) 1 All derived from impacted groundwater Exposure Frequency (EF, days/yr) 104 Assume groundwater used to irrigate 2 days per week Exposure Duration (ED, years) 10 Duration of exposure as per NEPM 1999 and USEPA 1989 Age Dependant Adjustment Factor (ADAF) - where relevant 3 Relevant for children aged 2 to <16 years as per USEPA 2005 Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC Background air Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Air (Ca) Inhalation Exposure Inhalation Exposure Non- Chronic Hazard - - Quotient Non (mg/m 3 ) -1 (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (unitless) (unitless) 1,2-Dichloroethane (EDC) 2.8E E E E E-8 8% -- Vinyl chloride 8.8E E E E E-7 90% -- Carbon tetrachloride 6.1E-03 40% 3.7E E E E % Trichloroethene (TCE) 4.3E E E E E E E-9 1% % Tetrachloroethene (PCE) 2.0E-02 10% 1.8E E E E % TOTAL 2.0E Includes consideration of early life susceptibility for non-threshold calculation

14 Exposure to Chemicals via Ingestion of Home-grown Produce (Irrigated with Extracted Groundwater) Daily ChemicalIntake FV FV IR FV FH B EF ED BW AT (mg/kg/day) Parameters Relevant to Quantification of Exposure by Older Children Residents - Western Margin Ingestion Rate of Fruit and Veg (IR FV kg/day) enhealth 2003 draft intake based on average of 8-15 yr intake Fraction Ingested that is Home-grown 35% Assume 35% of produce consumed each year is home-grown Bioavailability (B) 100% Assume 100% bioavailability Exposure Frequency (EF, days/year) 337 Assume time at home each year Exposure Duration (ED, years) 10 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 34.5 As per USEPA 1997 Age Dependant Adjustment Factor (ADAF) - wh 3 Relevant for children aged 2 to <16 years as per USEPA 2005 Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) 3650 USEPA 1989 and CSMS 1996 Non- Slope Factor TDI Background Intake (% TDI) TDI Allowable for Assessment (TDI- in Produce (C FV ) Daily Intake Non Non- Calculated Chronic Hazard Quotient (mg/kg-day) -1 (mg/kg/day) (mg/kg/day) (mg/kg) (mg/kg/day) (mg/kg/day) (unitless) (unitless) 1,2-Dichloroethane (EDC) 1.0E E E E-8 0% -- Vinyl chloride 2.3E E E E-5 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E % Trichloroethene (TCE) 7.8E E E E E E-9 0% % Tetrachloroethene (PCE) 1.4E-02 10% 1.3E E E % TOTAL 1.1E Includes consideration of early life susceptibility for non-threshold calculation

15 Inhalation of Volatiles (derived from Groundwater Source) Inhalation ExposureConc V a ET FI EF ED AT (mg/m 3 ) Parameters Relevant to Quantification of Exposure by Young Children Residents - Western Margin Exposure Time Indoors (ET, hr/day) 20 Time spend indoors every day (as per NEPM 1999 and enhealth 2002) Exposure Time Outdoors (ET, hr/day) 4 Time spend indoors every day (as per Nap 1999 and enhealth 2002) Fraction Inhaled from Contaminated Source (FI, unitless) 1 Assume all of home above impacted soils Exposure Frequency (EF, days/yr) 337 Assume time at home each year Exposure Duration (ED, years) 6 Duration of exposure as per NEPM 1999 and USEPA 1989 Age Dependant Adjustment Factor (ADAF) - where relevant 10 Relevant for children aged <2 years as per USEPA Relevant for children aged <2 to <16 years as per USEPA 2005 Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC Background air Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Air (Ca) Inhalation Exposure Inhalation Exposure Non- Chronic Hazard - - Quotient Non (mg/m 3 ) -1 (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (unitless) (unitless) 1,2-Dichloroethane (EDC) 2.8E E E E E-8 60% -- Dichloromethane 2.0E-01 20% 1.6E E E E % Carbon tetrachloride 6.1E-03 40% 3.7E E E E % Trichloroethene (TCE) 4.3E E E E E E E-8 40% % Tetrachloroethene (PCE) 2.0E-02 10% 1.8E E E E % TOTAL 6.8E Ca oncentration in air weighted indoor and outdoor concentration Includes consideration of early life susceptibility for non-threshold calculation

16 Exposure to Chemicals via Incidental Ingestion of Water (Extracted Groundwater) Daily Chemical Intake IW W IR W FI B EF ED (L/kg/day) BW AT Parameters Relevant to Quantification of Exposure by Young Children Residents - Western Margin Ingestion Rate (Irw, L/day) 0.2 Assumed intake when using water in backyard Fraction Ingested from Source 100% Assumed to be 100% Bioavailability (B) 100% Assume 100% bioavailability via ingestion of chemicals in water. Exposure Frequency (EF, days/year) 64 Assume contact with water 2 days per week in warmer 8 months Exposure Duration (ED, years) 6 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 13.2 NEPM 1999 and enhealth 2002 Age Dependant Adjustment Factor (ADAF) - wh 10 Relevant for children aged <2 years as per USEPA Relevant for children aged <2 to <16 years as per USEPA 2005 Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) 2190 USEPA 1989 and CSMS 1996 Non- Slope Factor TDI Background Intake (% TDI) TDI Allowable for Assessment (TDI- in Water (Cw) Daily Intake Non Non- Calculated Chronic Hazard Quotient (mg/kg-day) -1 (mg/kg/day) (mg/kg/day) (mg/l) (mg/kg/day) (mg/kg/day) (unitless) (unitless) 1,2-Dichloroethane (EDC) 1.0E E E E-7 0% -- Vinyl chloride 2.3E E E E-4 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E % Trichloroethene (TCE) 7.8E E E E E E-8 0% % Tetrachloroethene (PCE) 1.4E-02 10% 1.3E E E % TOTAL 1.3E Includes consideration of early life suseptability for non-threshold calculation

17 Dermal Exposure to Chemicals via Contact with Water (Extracted Groundwater) Daily Chemical Intake DW W SAw ET DP CF EF ED BW AT (L/kg/day) Parameters Relevant to Quantification of Exposure by Young Children Residents - Western Margin Surface Area (Saw, cm 2 ) 7290 Whole body surface area (male child 3-4 yrs, 90 percentile, USEPA 1997) Exposure Time (ET, hr/day) 2 Assume contact with water for 2 hours each time GW is used Conversion Factor (CF, L/cm 3 ) 1.E-03 Conversion of units Dermal Permeability (cm/hr) Chemical-specific (as below) Exposure Frequency (EF, days/yr) 64 Assume contact with water 2 days per week in warmer 8 months Exposure Duration (ED, years) 6 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 13.2 NEPM 1999 and enhealth 2002 Age Dependant Adjustment Factor (ADAF) - wher 10 Relevant for children aged <2 years as per USEPA Relevant for children aged <2 to <16 years as per USEPA 2005 Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) 2190 USEPA 1989 and CSMS 1996 Non- Slope Factor TDI Background TDI Allowable for Intake (% TDI) Assessment (TDI- Dermal Permeability (DP) in Water (Cw) Daily Intake Non- Non- Calculated Chronic Hazard Quotient (mg/kg-day) -1 (mg/kg/day) (mg/kg/day) (cm/hr) (mg/l) (mg/kg/day) (mg/kg/day) (unitless) (unitless) 1,2-Dichloroethane (EDC) 1.0E E E E E-8 0% -- Vinyl chloride 2.3E E E E E-5 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E E % Trichloroethene (TCE) 7.8E E E E E E E-8 0% % Tetrachloroethene (PCE) 1.4E-02 10% 1.3E E E E % 7.7E Includes consideration of early life susceptibility for non-threshold calculation

18 Inhalation of Volatiles (derived from Irrigation of Groundwater) Inhalation Exposure Conc V a ET FI EF ED AT (mg/m 3 ) Parameters Relevant to Quantification of Exposure by Young Children Residents - Western Margin Exposure Time (ET, hr/day) 1 Assume groundwater used to irrigate for 1 hour each time Fraction Inhaled from Contaminated Source (FI, unitless) 1 All derived from impacted groundwater Exposure Frequency (EF, days/yr) 104 Assume groundwater used to irrigate 2 days per week Exposure Duration (ED, years) 6 Duration of exposure as per NEPM 1999 and USEPA 1989 Age Dependant Adjustment Factor (ADAF) - where relevant 10 Relevant for children aged <2 years as per USEPA Relevant for children aged <2 to <16 years as per USEPA 2005 Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC Background air Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Air (Ca) Inhalation Exposure Inhalation Exposure Non- Chronic Hazard - - Quotient Non (mg/m 3 ) -1 (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (unitless) (unitless) 1,2-Dichloroethane (EDC) 2.8E E E E E-9 8% -- Vinyl chloride 8.8E E E E E-7 90% -- Carbon tetrachloride 6.1E-03 40% 3.7E E E E % Trichloroethene (TCE) 4.3E E E E E E E-9 2% % Tetrachloroethene (PCE) 2.0E-02 10% 1.8E E E E % TOTAL 1.2E Includes consideration of early life susceptibility for non-threshold calculation

19 Exposure to Chemicals via Ingestion of Home-grown Produce (Irrigated with Extracted Groundwater) Daily ChemicalIntake FV FV IR FV FH B EF ED BW AT (mg/kg/day) Parameters Relevant to Quantification of Exposure by Young Children Residents - Western Margin Ingestion Rate of Fruit and Veg (IR FV kg/day) As per enhealth 2003 Fraction Ingested that is Home-grown 35% Assume 35% of produce consumed each year is home-grown Bioavailability (B) 100% Assume 100% bioavailability Exposure Frequency (EF, days/year) 337 Assume time at home each year Exposure Duration (ED, years) 6 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 13.2 NEPM 1999 and enhealth 2002 Age Dependant Adjustment Factor (ADAF) - wh 10 Relevant for children aged <2 years as per USEPA Relevant for children aged <2 to <16 years as per USEPA 2005 Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) 2190 USEPA 1989 and CSMS 1996 Non- Slope Factor TDI Background Intake (% TDI) TDI Allowable for Assessment (TDI- in Produce (C FV ) Daily Intake Non Non- Calculated Chronic Hazard Quotient (mg/kg-day) -1 (mg/kg/day) (mg/kg/day) (mg/kg) (mg/kg/day) (mg/kg/day) (unitless) (unitless) 1,2-Dichloroethane (EDC) 1.0E E E E-8 0% -- Vinyl chloride 2.3E E E E-5 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E % Trichloroethene (TCE) 7.8E E E E E E-9 0% % Tetrachloroethene (PCE) 1.4E-02 10% 1.3E E E % TOTAL 1.2E Includes consideration of early life susceptibility for non-threshold calculation

20 Inhalation of Volatiles (derived from Groundwater Source) Inhalation ExposureConc V a ET FI EF ED AT (mg/m 3 ) Parameters Relevant to Quantification of Exposure by Intrusive Worker in Excavation Exposure Time (ET, hr/day) 8 Assumed time spent in excavation Fraction Inhaled from Contaminated Source (FI, unitless) 1 Assume all of workplace above impacted soils Exposure Frequency (EF, days/yr) 10 Assume intrusive works on services occur over 10 days each year Exposure Duration (ED, years) 5 Assume works occur on the same site over 5 years Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC Background air Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Excavation Air (Ca) Inhalation Exposure - Non Inhalation Exposure - Non- Chronic Hazard Quotient (mg/m 3 ) -1 (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (mg/m 3 ) (unitless) (unitless) 1,2-Dichloroethane (EDC) 2.8E E E E E-9 89% -- Dichloromethane 2.0E-01 20% 1.6E E E E % Carbon tetrachloride 6.1E-03 40% 3.7E E E E % Trichloroethene (TCE) 4.3E E E E E E E-10 11% Tetrachloroethene (PCE) 2.0E-02 10% 1.8E E E E % TOTAL 1.8E Ca = 100 times larger than estimated in outdoor air, conservative estimate for excavations where air flow is limited

21 Summary of for RME Exposure - Western Margin Pathway Non s s Hazard Index Intrusive Workers Inhalation of volatile CHCs in excavations 1.8E Total 2E Adult Residents Inhalation of CHCs indoors and outdoors (from GW source) 4.2E Incidental ingestion of CHCs during backyard use of extracted GW 2.0E Dermal contact with CHCs during backyard use of extracted GW 1.8E Inhalation of CHCs during irrigation of extracted GW 1.0E Ingestion of CHCs accumulated in produce irrigated with extracted GW 4.2E Total (including exposures associated with extraction and use of GW) 4E Total (no GW use) 4E Older Child Residents Inhalation of CHCs indoors and outdoors (from GW source) 9.4E Incidental ingestion of CHCs during backyard use of extracted GW 8.0E Dermal contact with CHCs during backyard use of extracted GW 5.1E Inhalation of CHCs during irrigation of extracted GW 2.0E Ingestion of CHCs accumulated in produce irrigated with extracted GW 1.1E Total (including exposures associated with extraction and use of GW) 1E Total (no GW use) 9E Young Child Residents Inhalation of CHCs indoors and outdoors (from GW source) 6.8E Incidental ingestion of CHCs during backyard use of extracted GW 1.3E Dermal contact with CHCs during backyard use of extracted GW 7.7E Inhalation of CHCs during irrigation of extracted GW 1.2E Ingestion of CHCs accumulated in produce irrigated with extracted GW 1.2E Total (including exposures associated with extraction and use of GW) 2E Total (no GW use) 7E Lifetime (including exposures associated with extraction and use of GW) 8E Lifetime (no GW use) 6E