Human Health Risk Assessment - Raytheon

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34 Human Health Risk Assessment DRAFT potential carcinogens is not calculated based on the childhood exposure duration because the LADD is higher (i.e., more protective) based on the longer-term exposure scenario for the adult. EPCs are provided in Table 5 and exposure factors are summarized in Table 6. Because the Pinellas Trail is located immediately adjacent to the Site, we have used on-Site groundwater concentrations to estimate outdoor air levels on the Pinellas Trail. Dose and risk calculations for potential exposures to COPCs by users of the Pinellas Trail via inhalation of outdoor air are provided in Appendix A; Table A-10. 4.3.9 Apartment/Condo Complex Landscaper The Brandywine Apartments and Stone’s Throw Condominium Complex are located east of the Pinellas Trail. There are two irrigation wells on the Brandywine property and a single irrigation well on the Stone’s Throw Condominium property. All three irrigation wells are more than 200 feet deep and cased to a minimum depth of 100 feet. The irrigation well on the Stone’s Throw Condominium property has been sampled over the past several years and no COPCs have been detected above FDEP GCTLs. 10 Because existing irrigation wells are screened in the unaffected Floridan aquifer, no potential exposure pathways are complete for landscape/maintenance workers at the Brandywine Apartments and Stone’s Throw Condominium Complex. The only COPC detected in shallow groundwater in this area is 1,4-dioxane; however, volatilization from groundwater is not considered to be a complete exposure pathway for this COPC. 4.3.10 Apartment/Condo Resident Similarly, because a clean water layer prevents potential volatilization of COPCs from underlying groundwater, no potential exposure pathways are complete for residents of the Brandywine Apartments and Stone’s Throw Condominium Complex. 4.3.11 Apartment/Condo Construction/Utility Worker Dermal Contact with Groundwater. For the purpose of estimating potential risks to utility workers involved in subsurface excavation activities, it is assumed that a construction/utility worker may be dermally exposed to saturated soil and groundwater for 2 hours per day, 8 days per year for 10 years. It is assumed that the worker is wearing long pants, shoes and a shortsleeved shirt but the worker’s head, hands, and forearms could be exposed to groundwater. The dermally absorbed dose of COPCs received from contact with groundwater is calculated using equations (4-22) through (4-24) and the LADD is calculated using equation (4-21) with the exception that the ADD is replaced by the DAD. Exposure point concentrations for off-Site 10 1,4-dioxane was detected at a concentration of 1.9 µg/L in April, 2008 but was not detected in a second, follow-up sample from the same well.
35 Human Health Risk Assessment DRAFT shallow groundwater are reported in Table 5 and exposure factors for off-Site utility/construction workers are summarized in Table 6. Dose and risk calculations for potential exposures to COPCs via dermal contact with exposed groundwater by off-Site construction/utility workers are provided in Appendix A; Table A-11. Incidental Ingestion of Soil. Some incidental ingestion of soil may occur during subsurface excavation activities. The average daily dose (ADD) from ingestion of soil is calculated using equation (4-25). The LADD is calculated using equation (4-21). Subsurface soil concentrations were estimated using equation (4-19) and exposure point concentrations for subsurface soils off-Site are reported in Table 5. Soil parameters were chosen to be consistent with a loamy sand with a dry soil bulk density of 1.62 L/kg and a volumetric water content of 39% for saturated soils. Exposure point concentrations for off-Site soils are reported in Table 5 and exposure factors for off-Site utility/construction workers are summarized in Table 6. Dose and risk calculations for potential exposures to COPCs via incidental ingestion of subsurface soil by off-Site construction/utility workers are provided in Appendix A; Table A-12. Inhalation of Air During Subsurface Excavation. If groundwater containing COPCs is exposed during the subsurface excavation activities, volatile constituents may be released to outdoor air. The ADD received from inhalation of outdoor air in the vicinity of the subsurface excavation is calculated according to equation (4-20) where the EPC is the concentration of COPCs in outdoor air as described in sections 4.2.5. The LADD is calculated using equation (4-21). Exposure point concentrations for off-Site outdoor air in the vicinity of subsurface excavation activities are reported in Table 5 and exposure factors for off-Site construction/utility workers are summarized in Table 6. Dose and risk calculations for potential exposures to COPCs via inhalation of outdoor air by off- Site construction/utility workers involved in subsurface excavation activities are provided in Appendix A; Table A-13. 4.3.12 Off-Site Residents In off-Site areas above the area of impacted groundwater, residents may be exposed to COPCs via direct exposure to groundwater used for irrigation purposes via ingestion, dermal contact and inhalation. Additional potential exposure pathways for residential receptors include exposures to surface soil and ingestion of homegrown produce irrigated with groundwater. Dermal contact with irrigation water used for recreational purposes (to operate a sprinkler or fill a child’s wading pool) is also evaluated along with potential exposures from dermal contact with surface water. Because a clean water layer prevents potential volatilization of COPCs from underlying groundwater, indoor and outdoor air exposure pathways are considered to be incomplete. Use of Irrigation Water. In off-Site areas, the existence of an irrigation well can facilitate direct contact with COPCs in groundwater. A recent well survey conducted in 2008 identified a
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Page 5 and 6: Executive Summary 1 Human Health Ri
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Page 35 and 36: where: DAD = Dermal absorbed dose (
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Page 59 and 60: 7 Uncertainty Analysis 55 Human Hea
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DRAFT CSFd RfDd DA event C w DAD LA
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DRAFT Table A-9. Dose and Risk Calc
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DRAFT CSFd RfDd DA event C w DAD LA
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DRAFT Table A-13. Dose and Risk Cal
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Human Health Risk Assessment - Raytheon

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