Appendix H Risk Calculations Off-Site

Size: px

Start display at page:

Download "Appendix H Risk Calculations Off-Site"

Barnaby Butler
5 years ago
Views:

1 Appendix H Calculations Off-Site

2 Exposure to Chemicals via Incidental Ingestion of Water (Extracted Groundwater) IR (L/kg/day) W FIBEFED Daily ChemicalIntakeIW CW BWAT Parameters Relevant to Quantification of Exposure by Adult Workers - Industrial/Irrigation Water Ingestion Rate (Irw, L/day) 0.05 Incidental ingestion of 50 ml water 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) 96 Assume contact with industrial water 2 days per work week Exposure Duration (ED, years) 30 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 78 as per enhealth (2012) 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) Mercury (as methyl mercury) 2.3E-04 20% 1.8E E E % Mercury (as total, inroganic) 6.0E-04 40% 3.6E E E % TOTAL 0.12

3 Exposure to Chemicals via Incidental Ingestion of Water (Extracted Groundwater) IR (L/kg/day) W FIBEFED Daily ChemicalIntakeIW CW BWAT Parameters Relevant to Quantification of Exposure by Adults - General Public - Irrigation Ingestion Rate (Irw, L/day) Incidental ingestion of 5 ml water during irrigation of gardens 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) 90 Frequency relevant to garden irrigation Exposure Duration (ED, years) 35 Duration of exposure assumed (enhealth 2012) Body Weight (BW, kg) 78 enhealth 2012 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) Mercury (as methyl mercury) 2.3E-04 20% 1.8E E E % Mercury (as total, inroganic) 6.0E-04 40% 3.6E E E % TOTAL 0.011

4 Exposure to Chemicals via Incidental Ingestion of Water (Extracted Groundwater) IR (L/kg/day) W FIBEFED Daily ChemicalIntakeIW CW BWAT Parameters Relevant to Quantification of Exposure by Older Children - General Public - Irrigation Ingestion Rate (Irw, L/day) Incidental ingestion of 5 ml water during irrigation of gardens 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) 90 Frequency relevant to garden irrigation (more conservative than municipal 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 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) Mercury (as methyl mercury) 2.3E-04 20% 1.8E E E % Mercury (as total, inroganic) 6.0E-04 40% 3.6E E E % TOTAL 0.025

5 Exposure to Chemicals via Incidental Ingestion of Water (Extracted Groundwater) IR (L/kg/day) W FIBEFED Daily ChemicalIntakeIW CW BWAT Parameters Relevant to Quantification of Exposure by Young Children - General Public - Irrigation Ingestion Rate (Irw, L/day) Incidental ingestion of 5 ml water during irrigation of gardens 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) 90 Frequency relevant to garden irrigation (more conservative than municipal Exposure Duration (ED, years) 6 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 13.2 Asper NEPM 1999 and enhealth 2002 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) Mercury (as methyl mercury) 2.3E-04 20% 1.8E E E % Mercury (as total, inroganic) 6.0E-04 40% 3.6E E E % TOTAL 0.066

6 Dermal Exposure to Chemicals via Contact with Water (Extracted Groundwater) DailyChemical Intake C DW W SAw ETDPCFEFED BW AT (L/kg/day) Parameters Relevant to Quantification of Exposure by Adult Workers - Industrial/Irrigation Water Surface Area (Saw, cm 2 ) 1120 Workers get hands wet (90% for adult males, USEPA 1997) during operation of the bore and watering activities Exposure Time (ET, hr/day) 8 Assume hands remain wet all day when 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) 96 Assume contact with industrial water 2 days per work week Exposure Duration (ED, years) 30 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 78 as per enhealth (2012) 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 % Tota l 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) Mercury (as methyl mercury) 2.3E-04 20% 1.8E E E E % Mercury (as total, inroganic) 4.2E-05 40% 2.5E E E E % 0.30

7 Dermal Exposure to Chemicals via Contact with Water (Extracted Groundwater) DailyChemical Intake C DW W SAw ETDPCFEFED BW AT (L/kg/day) Parameters Relevant to Quantification of Exposure by Adults - General Public - Irrigation Surface Area (Saw, cm 2 ) 6300 Exposed skin surface area for adults as per enhealth 2012 Exposure Time (ET, hr/day) 1 Assume adults remain wet for 1 hour each time 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) 90 Frequency relevant to garden irrigation (more conservative than municipal Exposure Duration (ED, years) 35 Duration of exposure assumed (enhealth 2012) Body Weight (BW, kg) 78 enhealth 2012 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) Mercury (as methyl mercury) 2.3E-04 20% 1.8E E E E % Mercury (as total, inroganic) 4.2E-05 40% 2.5E E E E % 0.20

8 Dermal Exposure to Chemicals via Contact with Water (Extracted Groundwater) DailyChemical Intake C DW W SAw ETDPCFEFED BW AT (L/kg/day) Parameters Relevant to Quantification of Exposure by Older Children - General Public - Irrigation Surface Area (Saw, cm 2 ) 4865 Surface area of hands, lower legs, forearms and feet (USEPA 2011) Exposure Time (ET, hr/day) 1 Assume adults remain wet for 1 hour each time 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) 90 Frequency relevant to garden irrigation (more conservative than municipal 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 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) Mercury (as methyl mercury) 2.3E-04 20% 1.8E E E E % Mercury (as total, inroganic) 4.2E-05 40% 2.5E E E E % 0.35

10 Dermal Exposure to Chemicals via Contact with Water (Extracted Groundwater) DailyChemical Intake C DW W SAw ETDPCFEFED BW AT (L/kg/day) Parameters Relevant to Quantification of Exposure by Young Children - General Public - Irrigation Surface Area (Saw, cm 2 ) 2300 Exposed skin, hands, forearms, lower legs and feet as per enhealth 2012 Exposure Time (ET, hr/day) 1 Assume adults remain wet for 1 hour each time 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) 90 Frequency relevant to garden irrigation (more conservative than municipal Exposure Duration (ED, years) 6 Duration of exposure as per NEPM 1999 and USEPA 1989 Body Weight (BW, kg) 13.2 As per NEPM 1999 and enhealth 2002 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) Mercury (as methyl mercury) 2.3E-04 20% 1.8E E E E % Mercury (as total, inroganic) 4.2E-05 40% 2.5E E E E % 0.43

11 General Parameters Air s During Irrigation - Main Plumes (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 Mercury (as methyl mercury) E-05 Mercury (as total, inroganic) E-01 Mercury (as elemental) E E E E E E E E-05

12 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 Workers - Industrial/Irrigation Water Exposure Time (ET, hr/day) 8 Assume use of water for 8 hours each time Fraction Inhaled from Contaminated Source (FI, unitless) 1 All derived from impacted groundwater Exposure Frequency (EF, days/yr) 96 Assume contact with industrial water 2 days per work week Exposure Duration (ED, years) 30 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) Mercury (as methyl mercury) 8.1E-04 20% 6.4E Mercury (as total, inroganic) 2.1E-03 10% 1.9E Mercury (as elemental) 2.0E-04 10% 1.8E E E E % TOTAL

13 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 Adults - General Public - Irrigation Exposure Time (ET, hr/day) 1 Assume the general public near irrigation for 1 hour each time Fraction Inhaled from Contaminated Source (FI, unitless) 1 All derived from impacted groundwater Exposure Frequency (EF, days/yr) 90 Frequency relevant to garden irrigation (more conservative than municipal irrigation) 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) Mercury (as methyl mercury) 8.1E-04 20% 6.4E Mercury (as total, inroganic) 2.1E-03 10% 1.9E Mercury (as elemental) 2.0E-04 10% 1.8E E E E % TOTAL

14 VAPOUR PARTITIONING, EMISSION AND AIR DISPERSION MODEL FOR CONTAMINATED SOIL & GROUNDWATER SOURCES Using Johnson & Ettinger Model (USEPA 2003) for VI and ASTM (2002) for Outdoors and Excavations Calculated Air s - Slab on Grade Commercial Building Above Impacted Groundwater Off-Site Site Specific Physical Input Parameters Units Abbrev. Value Comments Top Layer (unsaturated zone) Sand/Fill Depth to Groundwater [m] vd1 2 Assumed Moisture Content [ml/g] mocon 0.08 Default for sand Friebel & Nadebaum (2011) Soil Bulk Density [g/ml] rhob Default for sand, Friebel & Nadebaum (2011) Density of Solids [g/ml] sd 2.65 default Total Soil Porosity [ml/ml] theta 0.39 Calculated (1 - (rhob/sd)) Volumetric Water Content [ml/ml] wacon Calculated (mocon*rhob) Volumetric Air Content [ml/ml] acon Calculated (theta-wacon) Capillary Fringe Thickness of Capillary Fringe [m] cd 0.1 Estimated for on-site areas Volumetric Water Content [ml/ml] cfwacon 0.35 Value representative of capillary fringe, ASTM (2002) Volumetric Air Content [ml/ml] cfacon 0.04 Calculated (theta2-cfwacon) Receptor Specific Input Parameters Units Abbrev. Value Comments Building Characteristics Depth of Basement [m] basement 0 Slab on grade Width of Building [m] bwidth 10 Assumed size of workspace above impacts Length of Building [m] blength 10 Assumed size of workspace above impacts Area of Emission - Building Area [m 2 ] emarea Calculated based on building dimensions Proportion of site above contaminated groundwater Conservative estimate from review of data Foundation/wall thickness [m] fthick 0.10 Minimum relevant for commercial/industrial buildings Height of Room [m] boxh 2.4 Assumed for off-site offices Hourly Volume Exchange of Fresh Air [exch/hr] exchanges 2 Minimum exchange rate as per BCA Fraction of Cracks in Walls and foundation - cracks Default Value for type of building, USEPA 2004 Qbuilding [cm 3 /s] Qb Calculated, USEPA 2004 Is advective vapour flow significant? - Adv yes Based on building type/assumptions adopted Qsoil [cm 3 /s] Qs 13.3 Based on Qb/Qs ratio of Acrack [cm 2 ] Ac 3800 Calculated from building area and crack ratio, USEPA 2004 Volumetric Water Content in foundation/wall cracks [ml/ml] fwacon 0.12 Default Value Volumetric Air Content in foundation/wall cracks [ml/ml] facon Default Value Outdoor Air Characteristics Length of Contaminated Area [m] length 15 Assumed area outdoors contributing to outdoor concentration Width of Contaminated Area [m] width 15 Assumed area outdoors contributing to outdoor concentration Wind Speed Outdoors [m/s] wspd 4.9 Average 9am and 3pm winds from Sydney Airport Height of Outdoor Mixing Zone [m] outboxh 1.5 Default Value relevant for outdoors and excavations

15 Chemical Specific Parameters Water Solubility (mg/l) Koc (cm 3 /g) MW (g/mol) Air Diffusion Coefficient (cm 2 /s) Water Diffusion Coefficient (cm 2 /s) Vapour Pressure (mmhg) Henry's Law Constant (unitless) Mercury (as elemental) E Note: Physical/chemical properties obtained from RAIS website (January 2010) Vapour Transport Calculations Deff Layer 1 (cm 2 /s) Effective Diffusion Soil to Surface (cm 2 /s) Deff Layer 3 (cm 2 /s) Deff Foundations and Cracks (cm 2 /s) Deff Capillary Fringe (cm 2 /s) Total Effective Diffusion (GW to surface) (cm 2 /s) Total Effective Diffusion (GW to excavation) (cm 2 /s) Mercury (as elemental) 2.21E E E E E E E-4 Modelled Air s from Groundwater Source Phase Partitioning Results Dissolved Phase GW (mg/l) Modelled Vapour Phase (g/cm 3 ) Saturated Vapour (g/cm 3 ) Free Phase Mole Fraction (mol/mol) above Free Phase (g/cm 3 ) Vapour Phase Adopted (g/cm 3 ) Mercury (as elemental) E E E E-11 Calculated Air s Vapour Phase at Source 3 Vapour Phase at Source (mg/m 3 ) JE Attenuation Coefficient (unitless) Indoor Air (mg/m 3 ) Outdoor Air (mg/m 3 ) Excavation Air (mg/m 3 ) Mercury (as elemental) 5.6E E E E E-08

16 Inhalation of Volatiles (derived from Groundwater Source) Inhalation Exposure Conc V C a ET FI EF AT ED (mg/m 3 ) Parameters Relevant to Quantification of Exposure by Adult Workers Exposure Time Indoors (ET, hr/day) 10 Assumed long workday Fraction Inhaled from Contaminated Source (FI, unitless) 1 Assume all areas affected by impacted groundwater Exposure Frequency (EF, days/yr) 240 Working days per year Exposure Duration (ED, years) 30 Working lifetime as per enhealth 2012 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) Mercury (as methyl mercury) 8.1E-04 20% 6.4E Mercury (as total, inroganic) 2.1E-03 10% 1.9E Mercury (as elemental) 2.0E-04 10% 1.8E E E E TOTAL

17 Inhalation of Volatiles (derived from Groundwater Source) Inhalation Exposure Conc V C a ET FI EF AT ED (mg/m 3 ) Parameters Relevant to Quantification of Exposure by General Public Visiting Area Exposure Time Indoors (ET, hr/day) 1 Assumed time spent indoors visiting businesses Fraction Inhaled from Contaminated Source (FI, unitless) 1 Assume all areas affected by impacted groundwater Exposure Frequency (EF, days/yr) 20 Assume visits to the premises in the area over 20 days each year Exposure Duration (ED, years) 10 Assume visits occur over 10 separate 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 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) Mercury (as methyl mercury) 8.1E-04 20% 6.4E Mercury (as total, inroganic) 2.1E-03 10% 1.9E Mercury (as elemental) 2.0E-04 10% 1.8E E E E TOTAL

18 Exposure to Chemicals via Incidental Ingestion of Water (shallow groundwater) IR (L/kg/day) W FIBEFED Daily ChemicalIntakeIW CW BWAT Parameters Relevant to Quantification of Exposure by Workers involved in Excavations Ingestion Rate (Irw, L/day) Incidental ingestion of 5 ml water 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) 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 Body Weight (BW, kg) 78 enhealth 2012 Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) 1825 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) Mercury (as methyl mercury) 2.3E-04 20% 1.8E E E % Mercury (as total, inroganic) 6.0E-04 40% 3.6E E E % TOTAL

19 Exposure to Chemicals via Incidental Ingestion of Water (shallow groundwater) DailyChemical Intake C DW W SAw ETDPCFEFED BW AT (L/kg/day) Parameters Relevant to Quantification of Exposure by Workers involved in Excavations Surface Area (Saw, cm 2 ) 3300 Exposed surface area for construction workers as per USEPA 2001 Exposure Time (ET, hr/day) 3.3 Assume workers in excavation and wet for 33% of time on site (total 10 hrs/day) 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) 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 Body Weight (BW, kg) 78 enhealth 2012 Averaging Time - Non (Atc, days) USEPA 1989 and CSMS 1996 Averaging Time - (Atn, days) 1825 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 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) Mercury (as methyl mercury) 2.3E-04 20% 1.8E E E E % Mercury (as total, inroganic) 4.2E-05 40% 2.5E E E E % 0.039

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 Adult Workers - Industrial Water Exposure Time (ET, hr/day) 10 Assume working day is 10 hours Fraction Inhaled from Contaminated Source (FI, unitless) 1 All derived from impacted groundwater 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 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) Mercury (as methyl mercury) 8.1E-04 20% 6.4E Mercury (as total, inroganic) 2.1E-03 40% 1.3E Mercury (as elemental) 2.0E-04 10% 1.8E E E E TOTAL

Appendix C Risk Calculations: Western Margin of Northern Plumes

Appendix C Risk Calculations: Western Margin of Northern Plumes Appendix C Calculations: Western Margin of Northern Plumes Consolidated Human Health Assessment - 2017 Table of Contents C1.0 Introduction... C-1 C2.0 Calculation of Exposure and : Young Children... C-2