Appendix C Risk Calculations: Western Margin of Northern Plumes

Transcription

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

2 Table of Contents C1.0 Introduction... C-1 C2.0 Calculation of Exposure and : Young Children... C-2 C3.0 Calculation of Exposure and : Older Children and Adults... C-11 C4.0 Calculation of Exposure and : Intrusive Workers... C-25 Consolidated Human Health Assessment

3 C1.0 Introduction This appendix presents the calculations undertaken to characterise risks to human health for all relevant receptors and exposure pathways associated with contamination along the Western Margin of the Northern Plumes within the 2017 CHHRA. The methodology adopted for the characterisation of risk is presented in Appendix A, and details relevant to the risk issues that require evaluation and exposure concentrations are presented in the main report. Consolidated Human Health Assessment C-1 P age

4 C2.0 Calculation of Exposure and : Young Children Consolidated Human Health Assessment C-2 P age

5 Calculation of Emissions into House with Crawl-Space - Young Children 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 floorin 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 ) Ccrawl space (ug/m 3 ) Cbuilding (ug/m 3 ) Cbuilding (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-01 Carbon Tetrachloride 5.2E E E E E+00 Trichloroethene 1.4E E E E E E-02 Tetrachloroethene 7.2E E E E E E-02 Calculation of Outdoor Air (Soil Screening Guidance 1996 and 2000) Chemical Measured Emission Rate from Surface Outside Outside ER (g/s/m 2 ) Coutside (ug/m 3 ) Coutside (mg/m 3 ) 1,2-Dichloroethane 1.67E E E-06 Dichloromethane 1.48E E E-04 Carbon Tetrachloride 0.00E E E+00 Trichloroethene 3.33E E E-06 Tetrachloroethene 3.33E E E-06 Consolidated Human Health Assessment C-3 P age

6 Air s During Irrigation - Young Children (Reference: Guidelines for the Assessment and Management of Petroleum contaminated Sites in New Zealand) General Parameters 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 COPC in Water (mg/l) Henry's Law (atm.m 3 /mol) Molecular Weight 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 Air (mg/m 3 ) in Soil Water (mg/l) Cw HL MW Kl Kg KL KL' fv Ms Cair Cwater 1,2-Dichloroethane (EDC) E E E E E E E E-02 Consolidated Human Health Assessment 2017 C-4 P age

7 Equations Uptake of Organic Chemicals into Crops from Water - Young Children (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 Uptake VG RCF log Kow RCF TSCF exp( (log Kow ) 2 ) log Kow Uptake 10 (1 MC ) f oc K oc where: where: VG = Correction 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) Calculation of Uptake Factors COPC log Kow (L/kg) Koc (ml/g) foc VG (unitless) Uptake into Root Crops Uptake into Above-Ground Crops RCF (mg/kg produce per mg/l) Uptake Factor (mg/kg produce per mg/l water) TSCF Potential for uptake? MC (g/g) Uptake Factor (mg/kg produce per mg/l water) 1,2-Dichloroethane (EDC) E E E-01 yes E-01 s Soil Water (mg/l) Root Crops (mg/kg produce) Above Ground Crops (mg/kg produce) Total Produce (19% root crops and 81% other crops) (mg/kg) COPC 1,2-Dichloroethane (EDC) 1.9E E E E-03 Consolidated Human Health Assessment 2017 C-5 P age

8 Inhalation of Volatiles (derived from Groundwater Source) Inhalation ExposureConc V C a ET FI EF ED (mg/m 3 ) AT Parameters Relevant to Quantification of Exposure by Young Children Residents - Western Margin Exposure Time Indoors (ET, hr/day) 20 Time spend indoors every day (enhealth 2012b) Exposure Time Outdoors (ET, hr/day) 4 Time spend outdoors every day (enhealth 2012b) Fraction Inhaled from Contaminated Source (FI, unitless) 1 Assume all of home above impacted groundwater Exposure Frequency (EF, days/yr) 365 Assumed time at home each year (enhealth 2012b) Exposure Duration (ED, years) 6 Duration of exposure Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC air Background Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Air (Ca) Inhalation Exposure - Non Inhalation Exposure - Non- Chronic Hazard (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 -- Dichloromethane 3.5E-01 20% 2.8E E E E % Carbon tetrachloride 6.1E-03 40% 3.7E Trichloroethene (TCE) 4.0E E-03 10% 1.8E E E E E Tetrachloroethene (PCE) 2.0E-01 10% 1.8E E E E TOTAL 3.8E Ca = in air weighted indoor and outdoor concentration Consolidated Human Health Assessment 2017 C-6 P age

9 Exposure to Chemicals via Incidental Ingestion of Water (Extracted Groundwater) Daily Chemical Intake IW C 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 Body Weight (BW, kg) 15 Average for children aged 1-5 years as per enhealth (2012b) 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 Calculated Non Non- Chronic Hazard (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-8 100% -- TOTAL 8.8E-8 Consolidated Human Health Assessment 2017 C-7 P age

10 Dermal Exposure to Chemicals via Contact with Water (Extracted Groundwater) Daily Chemical Intake DW C W SAw ET DP BW CF EF ED (L/kg/day) AT Parameters Relevant to Quantification of Exposure by Young Children Residents - Western Margin Surface Area (Saw, cm 2 ) 6100 Whole body surface area for child aged 2-3 years (enhealth 2012b) 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 Body Weight (BW, kg) 15 Average for children aged 1-5 years as per enhealth (2012b) 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- Dermal Permeability (DP) in Water (Cw) Non- Daily Intake Calculated Non- (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-8 100% E-8 Chronic Hazard Consolidated Human Health Assessment 2017 C-8 P age

11 Inhalation of Volatiles (derived from Irrigation of Groundwater) Inhalation Exposure Conc V C 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 Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC air Background Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Air (Ca) Inhalation Exposure - Non Inhalation Exposure - Non- Chronic Hazard (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-9 100% -- TOTAL 6.0E-9 Consolidated Human Health Assessment 2017 C-9 P age

12 Exposure to Chemicals via Ingestion of Home-grown Produce (Irrigated with Extracted Groundwater) IR FV Daily Chemical Intake C FV FV FH BW B EF AT ED (mg/kg/day) Parameters Relevant to Quantification of Exposure by Young Children Residents - Western Margin Ingestion Rate of Fruit and Veg (IRFV kg/day) Intake for 2-3 year olds as per enhealth (2012b) Fraction Ingested that is Home-grown 10% Assume 10% total fruit and vegetable intake is homegrown, NEPM (2013) Bioavailability (B) 100% Assume 100% bioavailability Exposure Frequency (EF, days/year) 365 Assumed time at home each year (enhealth 2012b) Exposure Duration (ED, years) 6 Duration of exposure Body Weight (BW, kg) 15 Average for children aged 1-5 years as per enhealth (2012b) 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 Calculated Non Non- Chronic Hazard (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-9 100% -- TOTAL 7.9E-9 Consolidated Human Health Assessment 2017 C-10 P age

13 C3.0 Calculation of Exposure and : Older Children and Adults Consolidated Human Health Assessment C-11 P age

14 Calculation of Emissions into House with Crawl-Space - Older Children and Adults 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 floorin 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 ) Ccrawl space (ug/m 3 ) Cbuilding (ug/m 3 ) Cbuilding (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 ) Coutside (ug/m 3 ) Coutside (mg/m 3 ) 1,2-Dichloroethane 5.50E E E-06 Dichloromethane 5.17E E E-04 Carbon Tetrachloride 3.00E E E-06 Trichloroethene 5.17E E E-06 Tetrachloroethene 8.83E E E-04 Consolidated Human Health Assessment C-12 P age

15 Air s During Irrigation - Older Children and Adults (Reference: Guidelines for the Assessment and Management of Petroleum contaminated Sites in New Zealand) General Parameters 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 COPC in Water (mg/l) Henry's Law (atm.m 3 /mol) Molecular Weight 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 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-01 Carbon tetrachloride E E E E E E E E-03 Trichloroethene (TCE) E E E E E E E E-03 in Soil Water (mg/l) Consolidated Human Health Assessment C-13 P age

16 Equations Uptake of Organic Chemicals into Crops from Water - Older Children and Adults (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 Uptake VG RCF log Kow RCF TSCF exp( (log Kow ) 2 ) log Kow Uptake 10 (1 MC ) f oc K oc where: where: VG = Correction 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) Calculation of Uptake Factors COPC log Kow (L/kg) Koc (ml/g) foc VG (unitless) Uptake into Root Crops Uptake into Above-Ground Crops RCF (mg/kg produce per mg/l) Uptake Factor (mg/kg produce per mg/l water) TSCF Potential for uptake? MC (g/g) Uptake Factor (mg/kg produce per mg/l water) 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 s COPC Soil Water (mg/l) Root Crops (mg/kg produce) Above Ground Crops (mg/kg produce) Total Produce (19% root crops and 81% other crops) (mg/kg) 1,2-Dichloroethane (EDC) 2.7E E E E-03 Vinyl chloride 1.3E E E E-02 Carbon tetrachloride 4.1E E E E-04 Trichloroethene (TCE) 6.0E E E E-04 Consolidated Human Health Assessment C-14 P age

17 Inhalation of Volatiles (derived from Groundwater Source) Inhalation ExposureConc V C a ET FI EF ED (mg/m 3 ) AT Parameters Relevant to Quantification of Exposure by Older Children Residents - Western Margin Exposure Time Indoors (ET, hr/day) 20 Time spend indoors every day (enhealth 2012b) Exposure Time Outdoors (ET, hr/day) 4 Time spend outdoors every day (enhealth 2012b) Fraction Inhaled from Contaminated Source (FI, unitless) 1 Assume all of home above impacted groundwater Exposure Frequency (EF, days/yr) 365 Assumed time at home each year (enhealth 2012b) Exposure Duration (ED, years) 10 Duration of exposure Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC air Background Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Air (Ca) Inhalation Exposure - Non Inhalation Exposure - Non- Chronic Hazard (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 43% -- Dichloromethane 3.5E-01 20% 2.8E E E E % Carbon tetrachloride 6.1E-03 40% 3.7E E E E % Trichloroethene (TCE) 4.0E E-03 10% 1.8E E E E E-8 57% % Tetrachloroethene (PCE) 2.0E-01 10% 1.8E E E E % TOTAL 1.3E Ca = in air weighted indoor and outdoor concentration Consolidated Human Health Assessment C-15 P age

18 Exposure to Chemicals via Incidental Ingestion of Water (Extracted Groundwater) Daily Chemical Intake IW C 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 Body Weight (BW, kg) 37 Average for children aged 6-15 years as per enhealth 2012b 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 Calculated Non Non- Chronic Hazard (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-8 0% -- Vinyl chloride 1.2E E E E-5 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E % Trichloroethene (TCE) 4.6E E-04 10% 4.5E E E E-8 0% % TOTAL 4.8E Consolidated Human Health Assessment C-16 P age

19 Dermal Exposure to Chemicals via Contact with Water (Extracted Groundwater) Daily Chemical Intake DW C W SAw ET DP BW CF EF ED (L/kg/day) AT 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 is average for children aged 6-16 years (enhealth 2012b) 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 Body Weight (BW, kg) 37 Average for children aged 6-15 years as per enhealth 2012b 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- Dermal Permeability (DP) in Water (Cw) Daily Intake Calculated Non- Non- (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 1.2E E E E E-5 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E E % Trichloroethene (TCE) 4.6E E-04 10% 4.5E E E E E-8 0% % 2.7E Chronic Hazard Consolidated Human Health Assessment C-17 P age

20 Inhalation of Volatiles (derived from Irrigation of Groundwater) Inhalation Exposure Conc V C 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 Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC air Background Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Air (Ca) Inhalation Exposure - Non Inhalation Exposure - Non- Chronic Hazard (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 6% -- Vinyl chloride 8.8E E E E E-7 92% -- Carbon tetrachloride 6.1E-03 40% 3.7E E E E % Trichloroethene (TCE) 4.0E E-03 10% 1.8E E E E E-9 2% % TOTAL 2.5E Consolidated Human Health Assessment C-18 P age

21 Exposure to Chemicals via Ingestion of Home-grown Produce (Irrigated with Extracted Groundwater) IR FV Daily Chemical Intake C FV FV FH BW B EF AT ED (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) Intake for 9-13 year old children as per enhealth (2012b) Fraction Ingested that is Home-grown 10% Assume 10% total fruit and vegetable intake is homegrown, NEPM (2013) Bioavailability (B) 100% Assume 100% bioavailability Exposure Frequency (EF, days/year) 365 Assumed time at home each year (enhealth 2012b) Exposure Duration (ED, years) 10 Duration of exposure Body Weight (BW, kg) 37 Average for children aged 6-15 years as per enhealth 2012b 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 (CFV) Daily Intake Calculated Non Non- Chronic Hazard (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-9 0% -- Vinyl chloride 1.2E E E E-6 99% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E % Trichloroethene (TCE) 4.6E E-04 10% 4.5E E E E-9 0% % TOTAL 2.2E Consolidated Human Health Assessment C-19 P age

22 Inhalation of Volatiles (derived from Groundwater Source) Inhalation ExposureConc V C a ET FI EF ED (mg/m 3 ) AT Parameters Relevant to Quantification of Exposure by Adult Residents - Western Margin Exposure Time Indoors (ET, hr/day) 20 Time spend indoors every day (enhealth 2012b) Exposure Time Outdoors (ET, hr/day) 4 Time spend outdoors every day (enhealth 2012b) Fraction Inhaled from Contaminated Source (FI, unitless) 1 Assume all of home above impacted groundwater Exposure Frequency (EF, days/yr) 365 Assumed time at home each year (enhealth 2012b) Exposure Duration (ED, years) 19 Duration of exposure as adult (based on 35 years in total at one home) Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC air Background Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Air (Ca) Inhalation Exposure - Non Inhalation Exposure - Non- Chronic Hazard (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 43% -- Dichloromethane 3.5E-01 20% 2.8E E E E % Carbon tetrachloride 6.1E-03 40% 3.7E E E E % Trichloroethene (TCE) 4.0E E-03 10% 1.8E E E E E-7 57% % Tetrachloroethene (PCE) 2.0E-01 10% 1.8E E E E % TOTAL 2.4E Ca = in air weighted indoor and outdoor concentration Consolidated Human Health Assessment C-20 P age

23 Exposure to Chemicals via Incidental Ingestion of Water (Extracted Groundwater) Daily Chemical Intake IW C 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) 19 Duration of exposure as adult (based on 35 years in total at one home) Body Weight (BW, kg) 78 Adult body weight as per enhealth 2012b Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) 6935 USEPA 1989 and CSMS 1996 Non- Slope Factor TDI Background Intake (% TDI) TDI Allowable for Assessment (TDI- in Water (Cw) Daily Intake Calculated Non Non- Chronic Hazard (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-8 0% -- Vinyl chloride 1.2E E E E-5 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E % Trichloroethene (TCE) 4.6E E-04 10% 4.5E E E E-8 0% % TOTAL 4.4E Consolidated Human Health Assessment C-21 P age

24 Dermal Exposure to Chemicals via Contact with Water (Extracted Groundwater) Daily Chemical Intake DW C W SAw ET DP BW CF EF ED (L/kg/day) AT 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) 19 Duration of exposure as adult (based on 35 years in total at one home) Body Weight (BW, kg) 78 Adult body weight as per enhealth 2012b Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) 6935 USEPA 1989 and CSMS 1996 Non- Slope Factor TDI Background Intake (% TDI) TDI Allowable for Assessment (TDI- Dermal Permeability (DP) in Water (Cw) Daily Intake Calculated Non- Non- (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 1.2E E E E E-5 100% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E E % Trichloroethene (TCE) 4.6E E-04 10% 4.5E E E E E-8 0% % 3.7E Chronic Hazard Consolidated Human Health Assessment C-22 P age

25 Inhalation of Volatiles (derived from Irrigation of Groundwater) Inhalation Exposure Conc V C 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) 19 Duration of exposure as adult (based on 35 years in total at one home) Averaging Time - Non (Atc, hours) USEPA 2009 Averaging Time - (Atn, hours) USEPA 2009 Inhalation Unit Chronic TC air Background Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Air (Ca) Inhalation Exposure - Non Inhalation Exposure - Non- Chronic Hazard (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 6% -- Vinyl chloride 8.8E E E E E-7 92% -- Carbon tetrachloride 6.1E-03 40% 3.7E E E E % Trichloroethene (TCE) 4.0E E-03 10% 1.8E E E E E-9 2% % TOTAL 4.7E Consolidated Human Health Assessment C-23 P age

26 Exposure to Chemicals via Ingestion of Home-grown Produce (Irrigated with Extracted Groundwater) IR FV Daily Chemical Intake C FV FV FH BW B EF AT ED (mg/kg/day) Parameters Relevant to Quantification of Exposure by Adult Residents - Western Margin Ingestion Rate of Fruit and Veg (IR FV kg/day) Intake for adults aged 19 years and older as per enhealth 2012b Fraction Ingested that is Home-grown 10% Assume 10% total fruit and vegetable intake is homegrown, NEPM (2013) Bioavailability (B) 100% Assume 100% bioavailability Exposure Frequency (EF, days/year) 365 Assumed time at home each year (enhealth 2012b) Exposure Duration (ED, years) 19 Duration of exposure as adult (based on 35 years in total at one home) Body Weight (BW, kg) 78 Adult body weight as per enhealth 2012b Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) 6935 USEPA 1989 and CSMS 1996 Non- Slope Factor TDI Background Intake (% TDI) TDI Allowable for Assessment (TDI- in Produce (CFV) Daily Intake Calculated Non Non- Chronic Hazard (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-9 0% -- Vinyl chloride 1.2E E E E-6 99% -- Carbon tetrachloride 1.4E-03 40% 8.5E E E % Trichloroethene (TCE) 4.6E E-04 10% 4.5E E E E-9 0% % TOTAL 2.4E Consolidated Human Health Assessment C-24 P age

27 C4.0 Calculation of Exposure and : Intrusive Workers Consolidated Human Health Assessment C-25 P age

28 Inhalation of Volatiles (derived from Groundwater Source) Inhalation ExposureConc V C a ET FI EF ED (mg/m 3 ) AT 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 air Background Intake (% Chronic TC) Chronic TC Allowable for Assessment (TC- Daily Exposure Calculated in Excavation Air (Ca) Inhalation Exposure - Non Inhalation Exposure - Non- Chronic Hazard (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 98% -- Dichloromethane 3.5E-01 20% 2.8E E E E % Carbon tetrachloride 6.1E-03 40% 3.7E E E E % Trichloroethene (TCE) 4.0E E-03 10% 1.8E E E E E-9 2% % Tetrachloroethene (PCE) 2.0E-01 10% 1.8E E E E % TOTAL 8.2E Ca = 100 times larger than estimated in outdoor air, conservative estimate for excavations where air flow is limited Consolidated Human Health Assessment C-26 P age