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Evaluation of the public health risks associated with former Manufactured Gas Plants

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Title:
Evaluation of the public health risks associated with former Manufactured Gas Plants
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English
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DeHate, Robin Brewer
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University of South Florida
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Subjects / Keywords:
Soil vapor intrusion
Risk assessment
Benzene
Inhalation unit risk
Cancer
Dissertations, Academic -- Public Health -- Doctoral -- USF   ( lcsh )
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non-fiction   ( marcgt )

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Summary:
ABSTRACT: Regulatory agencies have recently focused on assessing the potential for soil vapor intrusion (SVI) and risk posed to occupants of residential and commercial properties overlying and surrounding former Manufactured Gas Plants (MGPs). This study evaluated the potential for SVI at 10 commercial buildings and 26 single family and multi-family residential properties overlying and/or adjacent to three former MGPs. The potential for SVI exposure was categorized into three groupings according to thickness of the vadose zones: no vadose zone; 0 - 6 feet thick, and 6 to 25 feet thick. Indoor and outdoor air and soil vapor samples were collected and analyzed for VOCs by the USEPA Method TO-15. These findings were compared to federal and state regulatory background data sets. The results did not identify evidence of MGP-related soil vapor intrusion from any of the 36 sites regardless of depth to water table or proximity to MGP source tar or dissolved phase plumes.In addition, comparative risks were calculated based on maximum and mean concentrations for benzene, toluene, ethylbenzene, and xylenes measured in ambient air samples, soil vapor, and indoor air. These chemicals were selected based on frequency of detection within the data sets. Hazard Indexes were calculated using the study results and the mean, maximum and 95th percentile concentrations from regulatory data bases. Carcinogenic risks associated with benzene were calculated using both the measured mean and maximum study results and the mean, maximum and 95th percentile concentrations from state and federal data bases. The calculated Hazard Indexes were less than 1 or were comparable to the regulatory mean and maximum background levels. Calculated cancer risks for residential and occupational exposures ranged from 9.75x10⁻⁶ to 4.52x10⁻⁴. However background benzene exposure not related to former MGP sites ranged from 9.9x10⁻⁶ to 3.59x10⁻³.Cancer risk and exposures to indoor air, soil vapor or ambient air concentrations were equivalent or less than a normal resident in the northeast United States. No increased public health risks were associated with occupied residential or commercial properties overlying or surrounding MGPs.
Thesis:
Dissertation (Ph.D.)--University of South Florida, 2008.
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Includes bibliographical references.
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by Robin Brewer DeHate.
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Includes vita.

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Evaluation of the Public Health Risks Associ ated with Former Manufactured Gas Plants by Robin Brewer DeHate A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Environmenta l and Occupational Health College of Public Health University of South Florida Major Professor: Raymond D. Harbison, Ph.D. Ira S. Richards, Ph.D. Skai W. Schwartz, Ph.D. M. Rony Francois, Ph.D., M.D. Date of Approval: October 27, 2008 Keywords: Soil Vapor Intrusion, Risk Assessment, Benzene, Inhalation Unit Risk, Cancer Copyright 2008, Robin Brewer DeHate

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ii Dedication In loving memory of my father, William J ackson Brewer Sr.; “my life has been a poor attempt to imitate the man” (Dan Fogelberg). I love you Dad.

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Acknowledgements First I thank God for the blessings He ha s given me in my life; the biggest of those being my family. Without the sacrif ice, loving support and understanding of my wonderful husband Wade, and my children Al exis, Colin, and Corey, this work would not have been possible. I love you guys. Thanks Mom for always letting me know how much you love me and how proud you are of me. I love you too. I would like to thank each of my co mmittee members for their support through this journey of discovery. First I would lik e to thank Dr. Raymond D. Harbison, for his perseverance and, sometime needed kick in the butt, throughout this re search project. He is not only my mentor, but also my friend (w hich says a lot after spending so many years together). I would like to thank Dr. Ira Richards. He has been a motivator and never lost faith that I would finally get out of his hair. He also was one of those rare individuals who appreciated my sense of humor (and vice versa). To Dr. Skai Sc hwartz who, in spite of myself, taught me that Epidemiology act ually was interesting. And to Dr. Rony Francois for his support and encouragement. I would also like to thank Beverly Sanch ez and Michelle Seb ti, COPH Academic and Student Affairs, whose determined effo rts kept me enrolled each semester. You’re both the best of the best. In addition, I would like to thank my colleagues at GEI Consultants, Inc., Dennis Unites, David Terry, Brian Skelly, and Andrew Blicharz; without them this study would not have been possible. Thanks guys.

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i Table of Contents List of Tables ................................................................................................................ .... iiii List of Figures ............................................................................................................... .... vii List of Abbreviations ......................................................................................................... x Abstract ...................................................................................................................... ...... xiii Chapter One Introduction ................................................................................................... 1 Statement of the Problem .........................................................................................1 Chapter Two Health Effects Summary ............................................................................... 6 Risk Assessment Guidelines ..................................................................................12 Integrated Risk Information System (IRIS) ...............................................12 National Toxicology Program (NTP) ........................................................14 Agency for Toxic Substances and Disease Registry (ATSDR) .................14 International Agency for Research on Cancer (IARC) ..............................14 Benzene (Benzol, phenyl hydride, CAS #71-43-2) ...................................15 Toluene (methylbenzene, toluol, CAS # 108-88-3 ) ...................................17 Ethylbenzene (Ethylbe nzol, CAS # 100-41-4 ............................................18 Xylene Isomers (Xylenes, CAS # 1330-20-7, meta-Xylene, CAS # 108-38-3) (para-Xylene, CAS # 106-42-3)(ortho-Xylene, CAS # 95-47-6)......................................................................................................20 Chapter Three Methods and Materials .............................................................................. 25 Study Description...................................................................................................25 Risk Assessment ....................................................................................................31 Chapter Four Results......................................................................................................... 3 4 Chapter Five Discussion and Conclusions ...................................................................... 106

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ii List of References ........................................................................................................... 112 Bibliography .................................................................................................................. 117 About the Author ................................................................................................... End Page

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iii List of Tables Table 1. Carcinogens Associated with MGPs ..................................................................7 Table 2. Frequency of Detected Chemicals for No Vadose Zone ...................................8 Table 3. Frequency of Detected Chem icals for 06 feet Vadose Zone ...........................9 Table 4. Frequency of Detected Chem icals for 6 – 25 feet Vadose Zone .....................11 Table 5. Inhalation Reference Concentration (RfC) Summary ......................................22 Table 6. Inhalation Unit Risk (IUR) Summary ..............................................................23 Table 7. Weight of Evidence (WOE) Information Summary ........................................24 Table 8. EPA 2001 Building Assessmen t and Survey Evaluation (BASE) Background Concentrations for Indoor Air (ug/m3) ........................................35 Table 9. EPA 2001 Building Assessmen t and Survey Evaluation (BASE) Background Concentrations for Outdoor Air (ug/m3) .....................................35 Table 10. NYSDOH 2003 Study of Volatile Or ganic Chemicals in Air of Fuel Oil Heated Homes (ug/m3) – Indoor Air..........................................................36 Table 11. NYSDOH 2003 Study of Volatile Or ganic Chemicals in Air of Fuel Oil Heated Homes (ug/m3) – Outdoor Air .......................................................36 Table 12. Maximum Concentrations of Be nzene in Indoor Air versus Soil Vapor for Locations with No Vadose Zone ................................................................37 Table 13. Maximum Concentrations of Be nzene in Indoor Air versus Soil Vapor for Locations with 0 6 Feet Vadose Zone ......................................................40

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iv Table 14. Maximum Concentrations of Be nzene in Indoor Air versus Soil Vapor for Locations with 6 25 Feet Vadose Zone ....................................................42 Table 15. Maximum Concentrations of To luene in Indoor Air versus Soil Vapor for Locations with No Vadose Zone ................................................................43 Table 16. Maximum Concentration of Toluene by Location with 06 feet Vadose Zone ....................................................................................................46 Table 17. Maximum Concentration of To luene by Locations with 6 -25 feet Vadose Zone ....................................................................................................48 Table 18. Maximum Concentration of Ethylbenzene by Location with No Vadose Zone ....................................................................................................49 Table 19. Maximum Concentrations fo r Ethylbenzene by Location for Indoor Air vs Soil Vapor 0-6 Feet Vadose Zone .........................................................51 Table 20. Maximum Concentrations fo r Ethylbenzene by Location for Indoor Air vs Soil Vapor 625 Feet Vadose Zone ......................................................53 Table 21. Maximum Concentrations for m,p-Xylene by Location for Indoor Air vs Soil Vapor No Vadose Zone .......................................................................54 Table 22. Maximum Concentrations for m,p-Xylene by Location for Indoor Air vs Soil Vapor 0-6 Feet Vadose Zone ...............................................................57 Table 23. Maximum Concentrations for m,p-Xylene by Location for Indoor Air vs Soil Vapor 6-25 Feet Vadose Zone .............................................................59 Table 24. Maximum Concentrations for o-Xylene by Location for Indoor Air vs Soil Vapor No Vadose Zone ............................................................................60 Table 25. Maximum Concentrations for o-Xylene by Location for Indoor Air vs Soil Vapor 0-6 Feet Vadose Zone ....................................................................62 Table 26. Maximum Concentrations for o-Xylene by Location for Indoor Air vs Soil Vapor 6-25 Feet Vadose Zone ..................................................................63

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v Table 27. Minimum, Maximum and M ean Concentrations of Detected Chemicals in Outdoor Air by Thickness of Vadose Zone (ug/m3) ..................77 Table 28. Minimum and Maximum Concentr ations of Detected Chemicals in Indoor Air by Thickness of Vadose Zone (ug/m3)...........................................78 Table 29. Minimum and Maximum Concentr ations of Detected Chemicals in Soil Vapor by Thickness of Vadose Zone (ug/m3) ..........................................79 Table 30. Summary Table of Minimum, Maximum and Mean Concentrations of Highest Frequency Chemicals in Ou tdoor Air by Thickness of Vadose Zone (ug/m3) ....................................................................................................80 Table 31. Summary Table of Minimum, Maximum and Mean Concentrations of Highest Frequency Chemicals in Indoor Air by Thickness of Vadose Zone (ug/m3) ....................................................................................................80 Table 32. Summary Table of Minimum, Maximum and Mean Concentrations of Highest Frequency Chemicals in Soil Vapor by Thickness of Vadose Zone (ug/m3) ....................................................................................................80 Table 33. Hazard Indices for Mean Con centrations for Indoor Air by Vadose Zone .................................................................................................................81 Table 34. Hazard Indices for Maximu m Concentrations for Indoor Air by Vadose Zone ....................................................................................................81 Table 35. Hazard Indices for Mean Con centrations for Soil Vapor by Vadose Zone .................................................................................................................82 Table 36. Hazard Indices for Maximu m Concentrations for Soil Vapor by Vadose Zone ....................................................................................................83 Table 37. Hazard Indices for Mean Con centrations for Outdoor Air by Vadose Zone .................................................................................................................83 Table 38. Hazard Indices for Maximum Concentrations for Outdoor Air by Vadose Zone ....................................................................................................84

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vi Table 39. Hazard Indices for DOH Background Maximum, Mean and 95th Percentile Concentrations for Indoor Air .........................................................84 Table 40. Hazard Indices for DOH Background Maximum, Mean and 95th Percentile Concentrations for Outdoor Air ......................................................85 Table 41. Hazard Indices for EPA Background Maximum, Mean and 95th Percentile Concentrations for Indoor Air .........................................................85 Table 42. Hazard Indices for EPA Background Maximum, Mean and 95th Percentile Concentrations for Outdoor Air ......................................................86 Table 43. Cancer Inhalation Risks for Be nzene Mean Concentrations for Indoor Air from Study Results and EPA/DOH Background .......................................93 Table 44. Cancer Inhalation for Benzen e Maximum Concentrations for Indoor Air from Study Results and EPA/DOH Background .......................................94 Table 45. Cancer Inhalation Risks for Benzene Mean Concentrations for Soil Vapor from Study Result s and EPA/DOH Background ..................................96 Table 46. Cancer Inhalation Risks for Benzene Maximum Concentrations for Soil Vapor from Study Results and EPA/DOH Background ...........................97 Table 47. Cancer Inhalation Risks fo r Benzene Mean Concentrations for Outdoor Air from Study Resu lts and EPA/DOH Background ........................98 Table 48. Cancer Inhalation Risks for Benzene Maximum Concentrations for Outdoor Air from Study Resu lts and EPA/DOH Background ........................99

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vii List of Figures Figure 1. Example of Collection of Indoor Air Samples using Summa or equivalent canisters ..........................................................................................28 Figure 2. Example of Collection of So il Vapor Sample from a Temporary Soil Vapor Point using a Summa or equivalent canister ......................................29 Figure 3. Maximum Concentration of Benzene by Locations with No Vadose Zone .................................................................................................................39 Figure 4. Maximum Concentration of Be nzene by Locations with 0 – 6 feet Vadose Zone ....................................................................................................41 Figure 5. Maximum Concentration of Be nzene by Locations with 6 -25 feet Vadose Zone ....................................................................................................42 Figure 6. Maximum Concentration of Toluene by Location with No Vadose Zone .................................................................................................................45 Figure 7. Maximum Concentration of To luene by Locations with 06 feet Vadose Zone ....................................................................................................47 Figure 8. Maximum Concentration of To luene by Locations with 6 25 feet Vadose Zone ....................................................................................................48 Figure 9. Maximum Concentration of Ethylbenzene by Locations with No Vadose Zone ....................................................................................................50 Figure 10. Maximum Concentration of Ethyl benzene by Locations with 06 feet Vadose Zone ....................................................................................................52 Figure 11. Maximum Concentration of Ethylbenzene by Locations with ........................53 Figure 12. Maximum Concentration of m ,p-Xylene by Location with No Vadose Zone .................................................................................................................56

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viii Figure 13. Maximum Concentration of m ,p-Xylene by Location with 0-6 feet Vadose Zone ....................................................................................................58 Figure 14. Maximum Concentration of m,pXylene by Locations with 6 25 feet Vadose Zone ....................................................................................................59 Figure 15. Maximum Concentration of o-Xylene by Location with No Vadose Zone .................................................................................................................61 Figure 16. Maximum Concentration of o-Xylene by Location with 0-6 feet Vadose Zone ....................................................................................................63 Figure 17. Maximum Concentration of o-Xy lene by Locations with 6 25 feet Vadose Zone ....................................................................................................64 Figure 18. Difference in Frequency of Detections between Outdoor Air and Indoor Air with No Vadose Zone. ...................................................................68 Figure 19. Difference in Frequency of Detections between Outdoor Air and Indoor Air with a 0-6 Foot Vadose Zone. ........................................................69 Figure 20. Difference in Frequency of Detections between Outdoor Air and Indoor Air with a 6-25 Foot Vadose Zone. ......................................................70 Figure 21. Difference in Frequency of Detections between Indoor Air and Soil Vapor with No Vadose Zone. ..........................................................................71 Figure 22. Difference in Frequency of Detections between Indoor Air and Soil Vapor with a 0-6 Foot Vadose Zone. ...............................................................72 Figure 23. Difference in Frequency of Detections between Indoor Air and Soil Vapor with a 6-25 foot Vadose Zone. ..............................................................73 Figure 24. Difference in Fr equency of Detections be tween Outdoor Air and Soil Vapor with No Vadose Zone. ..........................................................................74 Figure 25. Difference in Fr equency of Detections be tween Outdoor Air and Soil Vapor with a 0-6 foot Vadose Zone. ................................................................75

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ix Figure 26. Difference in Fr equency of Detections be tween Outdoor Air and Soil Vapor with a 6-25 foot Vadose Zone. ..............................................................76 Figure 27. Hazard Index Comparison for Outdoor Air Mean Concentrations ..................87 Figure 28. Hazard Index Comparison for Ou tdoor Air Maximum Concentrations ..........88 Figure 29. Hazard Index Comparison for Indoor Air Mean Concentrations ....................89 Figure 30. Hazard Index Comparison for Indoor Air Maximum Concentrations .............90 Figure 31. Hazard Index Comparison for Soil Vapor Mean Concentrations ....................91 Figure 32. Hazard Index Comparison for Soil Vapor Maximum Concentrations ............92 Figure 33. Inhalation Cancer Risks for Be nzene Indoor Air Mean Concentrations .......100 Figure 34. Inhalation Cancer Risk s for Benzene Indoor Air Maximum Concentrations ...............................................................................................101 Figure 35. Inhalation Cancer Risks for Be nzene Soil Vapor Mean Concentrations .......102 Figure 36. Inhalation Cancer Risk s for Benzene Soil Vapor Maximum Concentrations ...............................................................................................103 Figure 37. Inhalation Cancer Risk s for Benzene Outdoor Air Mean Concentrations ...............................................................................................104 Figure 38. Inhalation Cancer Risks for Benzene Outdoor Air Maximum Concentrations ...............................................................................................105

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x List of Abbreviations ATSDR Agency for Toxic Substances and Disease Registry BASE Building Assessment and Survey Evaluation BMCL Benchmark Concentration Level BTEX Benzene, Toluene, Ethylbenzene, Xylene BTX Benzene, Toluene, Xylene CAS(RN) Chemical Abstract Service Registry Number CNS Central Nervous System CWG Carburetted Water Gas DOH New York State Department of Health ECG Electrocardiogram ECD Electron Capture Detector EPA United States Environmental Protection Agency EPRI Electric Power Research Institute FID Flame Ionization Detector GC/MS Gas Chromatography Mass Spectrophotometry HEC Human Equivalence Concentration HI Hazard Index HQ Hazard Quotient

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xi IARC International Agency for Research on Cancer IAIR Indoor Air IUR Inhalation Unit Risk LCS Laboratory Control Sample MGP Manufactured Gas Plant MRL Minimum Risk Level MS Matrix Spike MSD Matrix Spike Duplicate NAPL Non-aqueous Phase Liquid ND Non-detect NIOSH National Institute of Occupational Safety and Health NLM National Library of Medicine NOAEL No Observable Adverse Effects Level NRC National Research Council NTP National Toxicology Program NV No Vadose NYSDOH New York State Department of Health OAIR Outdoor Air PAHs Polycyclic Aromatic Hydrocarbons PID Photoionization Detector POD Point of Departure RfC Reference Concentration

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xii RfD Reference Dose RoC Report on Carcinogens SV Soil Vapor SVI Soil Vapor Intrusion SVOCs Semi-volatile Organic Compounds USEPA United States Environmental Protection Agency US United States of America VOCs Volatile Organic Compounds WOE Weight of Evidence

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xiii Evaluation of the Public Health Risks Associ ated with Former Manufactured Gas Plants Robin Brewer DeHate ABSTRACT Regulatory agencies have recently focu sed on assessing the potential for soil vapor intrusion (SVI) and risk posed to occupants of residential and commercial properties overlying and surrounding former Manufactured Gas Plants (MGPs). This study evaluated the potential for SVI at 10 commercial buildings and 26 single family and multi-family residential properties overlying and/or adjacent to three former MGPs. The potential for SVI exposure was categor ized into three groupings according to thickness of the vadose zones: no vadose zone; 0 6 feet thick, and 6 to 25 feet thick. Indoor and outdoor air and soil vapor samp les were collected and analyzed for VOCs by the USEPA Method TO-15. These findings were compared to federal and state regulatory background data sets. The results did not identify evid ence of MGP-related soil vapor intrusion from any of the 36 site s regardless of depth to water table or proximity to MGP source tar or dissolved phase plumes. In addition, comparative risks were ca lculated based on maximum and mean concentrations for benzene, toluene, ethylbenzene, and xylenes measured in ambient air samples, soil vapor, and indoor air. These chem icals were selected ba sed on frequency of detection within the data sets Hazard Indexes were calculat ed using the study results and

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xiv the mean, maximum and 95th percentile concentrations from regulatory data bases. Carcinogenic risks associated with benzen e were calculated using both the measured mean and maximum study results and the mean, maximum and 95th percentile concentrations from state and federal data bases. The calculated Hazard Indexes were less than 1 or were comparable to the regu latory mean and maximum background levels. Calculated cancer risks for residential a nd occupational exposures ranged from 9.75x10-6 to 4.52x10-4. However background benzene exposure not related to former MGP sites ranged from 9.9x10-6 to 3.59x10-3. Cancer risk and exposures to indoor air, soil vapor or ambient air concentrations were equivalent or less than a normal re sident in the northeast United States. No increased public health risks were associat ed with occupied residential or commercial properties overlying or surrounding MGPs.

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1 Chapter One Introduction Statement of the Problem Manufactured Gas Plants (MGP) have historica lly been used for generating local supplies of coal gas for decades during the early part of the 20th century. Manufactured gas supplied lighting, refrigeration, and heating to cities and encouraged the growth and development of the United States (US). Alt hough the coal gasification process generated a valuable product it also generated waste produ cts that, ultimately, c ontaminated the soil and groundwater surrounding these sites. With the advent of natural gas many of these manufactured gas systems were either converted from the use of coal to natural gas or abandoned. As a result of these activities, there are over 1,500 abandoned MGP sites in the US that present potential public health risks today (EPRI, 2008). The cost of remediation of these MGP sites range from one million dollars to tens of millions of dollars (EPRI, 2008). Without knowledge of th e potential contaminatio n associated with these former MGP sites many of these aba ndoned sites and the properties immediately abutting or adjacent to them, were redeve loped for residential and/or commercial purposes. Three processes were used to produce manufactured coal gas: Coal Carbonization Carbureted Water Gas (CWG)

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2 Oil Gas. Coal carbonization, used exclusively until 1875, heated bituminous coal in closed retorts with limited air contact. The gas was collected, cooled, and purified for use, while the coke was removed and sold or used. The gas was then measured, stored, and delivered to customers via underground pipes (EPA, 2004). The carbureted water gas process, introdu ced in the 1875, involved heating coal or coke in a generator into which steam wa s injected. Steam was fed through a bed of incandescent coke, producing a gas contai ning hydrogen and carbon monoxide. This gas (blue gas) then passed through two chambers containing hot firebrick, where oil was sprayed into the gas and crack ed into gaseous hydrocarbons and tar (Harkins, et.al., 1986). The most common oil gas process was pa tented in 1889. It is similar to the carbureted water gas process with a vaporizer replacing the carburetor. Oil was added to the reactor thereby generating more heat. Th e oil vapors were thermally cracked into gaseous hydrocarbons, tar, and carbon (l ampblack) (Harkins, et.al., 1986). All of these processes genera ted a dense, oily liquid byproduct known as coal tar. While the coal tar was a valuable by-product with many industrial us es, routine leaks and spills occurred that contaminated surface soil s, subsurface soils, and groundwater. From 1880 to 1950, MGPs produced approximately 15 trillion cubic feet of gas and approximately 11 billion gallons of tar as a by-product resulti ng in thousands of contaminated acres of land and millions of gallons of impacted water (Fischer et al, 1999).

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3 These contaminated sites have been targeted by both federal and state environmental agencies for assessment and re mediation. Previous assessments of these sites concentrated on the c ondition of the soil and groundwater at and surrounding these sites, however recent state and federal regulat ory agencies have focused on the potential hazards associated with soil vapor. Soil vapor intrusion (SVI) assessments of volatile chemicals associated with manufactured gas are being rout inely required by environmental regulatory agencies to evaluate the potential risks po sed to residents and occupants of commercial properties overly ing and surrounding former MGP sites. The purpose of this research was to eval uate the potential public health risks associated with former MGP sites to the human population located in residences and businesses adjacent to or above these cont aminated sites. Spec ifically, 1) What contaminants are present in the soil vapor, th e indoor air, and the ambient outdoor air; 2) Is the presence of chemical contaminants in the indoor air of these residences and commercial buildings the result of soil vapor intrusion; 3) What are the potential public health risks posed by these contaminants; and 4) Is this adjacent human population at greater risk of adverse health effects than that of a normal resident in the northeastern US. The goal of this risk assessment research is to evaluate whether there are complete exposure pathways from soil vapor to indoor air. In order for a complete exposure pathway to exist, vapors from MGP-related constituents would need to migrate through various pathways into residen tial or commercial buildings at concentrations that could result in an unacceptable human health risk. This study evaluated at total of 10 co mmercial and 26 single family and multifamily residential properties that were poten tially affected by SVI associated with the

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4 three former MGPs. All of these propertie s had potable water from municipal water sources. Each of the sites included in this study were located in th e northeastern US. This study evaluated the potential for SVI for pr operties overlying and immediately abutting MGP tar source material and properties ove rlying and adjacent to dissolved phased benzene, toluene, ethylbenzene and xylene (BTEX) and naphthalene plumes emanating from the MGPs. Further evaluation of the potential for SVI exposure was conducted to evaluate whether depth to groundwater influenced th e potential for SVI by categorizing each of the sites into three groupings according to dept h to the water table: no vadose zone; water table within 6 feet of the building slab (0-6 Feet Vadose Zone); and water table between 6 and 25 feet of the building slab (6-25 Feet Vadose Zone). Vadose zone is defined by the Britannica Encyclopedia (2008) as the region of aeration above the water table. This zone includes the capillary fringe above the wate r table, the height of which will vary according to the grain size of the sediments. In addition, comparative risk assessme nts were conducted on the five most frequently detected chemicals in the indoor air of the sampled buildings. These include benzene, toluene, ethylbenzen e, m,p-xylene, and o-xylene. For benzene, a known human carcinogen (NTP, 2005), cancer ri sk calculations were computed for the mean and maximum concentrations of benzene detected in the sample groups. For the noncarcinogenic chemicals, toluene, ethylbenzene, m,p-xylene, and o-xylene, hazard indices were calculated for both the mean and maximu m concentrations detected in the sample groups.

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5 The hypothesis that was tested was: Indoor air levels of volatile organic compounds are influenced by soil vapor concen trations from former MGP sites resulting in an increased risk of adverse health effect s for residents or occupants of buildings near or adjacent to thes e abandoned sites.

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6 Chapter Two Health Effects Summary Manufactured gas plants provided a major source of fuel for heating and lighting in many communities prior to the introduction of interstate natural gas pipelines in the 1950s. 1,500 to 3,000 plants were in operation in the United States during the period from the early 1800s to the 1960s, (EPRI, 1999) According to the EPA 3,000 – 5,000 MGP formerly operated in the US (EPA, 1999a). Coal tar and petroleum products derive d from the coal gasification process contain both volatile organic compounds (VOC s) and semi-volatile organic compounds (SVOCs). Many of these compounds, resi duals from the manufacturing process, impacted the soils and groundwater of thes e former plants. The VOCs consist of a mixture of benzene, toluen e, ethylbenzene, xylene isomers (BTEX), benzothiophene, carbon disulfide, n-decane, ndodecane, 2ethylthiophene, indan, indene, 2methylthiophene, 3methylthiophene, nona ne, styrene, 1,2,4,5tetramethylbenzene, thiophene, 1,2,3-trimethylbenzene, 1,2,4trim ethylbenzene, 1,3,5trimethylbenzene, and n-undecane. The SVOCs consist of a mixture of acenaphthene, acenaphthylene, anthracene, benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, benzo(e)pyrene, benzo(g,h,i)perylene, chry sene, dibenz(a,h)anthra cene, fluoranthene, fluorene, indeno(1,2,3-cd)pyrene, 2-methyl naphthalene, naphthalene, phenanthrene, phenols, and pyrene. Of these SVOCS napht halene and 2-methyl naphthalene are the

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7 semi-volatile components of coal tar most likely to be associated with soil vapor intrusion due to their volatility. These compounds can be present within sub-surface soils or as a dissolved phase groundwater plume. In some cases, these ch emical components may be present in nonaqueous phase liquids (NAPL) such as fuels, oils, or tar. The following table categorizes poten tially MGP-related compounds as known, probable or possible carcinogens and the agencies that have classified them as such: Table 1. Carcinogens Associated with MGPs Source: NTP1 EPA2 IARC3 Benzene X X X Benz[a]anthracene X X X Benzo[a]pyrene X X X Benzo[b]fluoranthene X X X Benzo[k]fluoranthene X X X Chrysene X Dibenz[a,h]anthracene X X X Indeno[1,2,3-cd]pyrene X X X Naphthalene X X X Styrene X Bolding indicates known carcinogen 1National Toxicology Program, 2005 2 U.S. Environmental Agency, 2005 3 International Agency for Research on Cancer, 2002 Of the above listed known, probable or possible carcinogens only benzene was detected at a high enough fre quency in the sample groups to be considered for further evaluation. For the non-carcinogenic chemicals toluene, ethylbenzen e, and the xylene isomers had the greatest frequency of detections in the sample groups.

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8 The highest percentage of detections in the outdoor air in the No Vadose Zone sample set for chemicals were benzene, tolu ene, m,p-xylene, ethylbe nzene, and o-xylene, respectively, as listed in Table 2. The highest percentage of detections in the indoor air in the No Vadose Zone sample set for chemicals were benzene, toluene, m,p-xylene, ethylbenzene, and o-xylene, respectively. The highest percentage of detections in soil vapor in the No Vadose Zone sample set for chemicals were toluene, benzene, nundecane, m,p-xylene, and et hylbenzene, respectively. Table 2. Frequency of Detected Chemicals for No Vadose Zone No Vadose Zone Frequency of Detection Frequency of Detection Frequency of Detection Chemical Name Outdoor Air Indoor Air Soil Vapor Benzene 24% 11% 10% Benzothiophene 0% 0% 1% Carbon disulfide 3% 2% 7% Decane, n1% 6% 7% Dodecane, n3% 5% 5% Ethylbenzene 9% 9% 6% Ethylthiophene, 20% 0% 0% Indan 0% 2% 2% Indene 0% 0% 3% Methylnaphthalene,10% 1% 1% Methylnaphthalene,20% 1% 2% Methylthiophene, 20% 0% 0% Methylthiophene, 30% 0% 0% Naphthalene 0% 2% 4% Nonane 1% 5% 5% Styrene 0% 3% 4% Tetramethylbenzene 1,2,4,50% 2% 2%

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9 Table 2. (continued) Thiophene 0% 0% 1% Toluene 27% 12% 11% Trimethylbenzene 1,2,30% 3% 4% Trimethylbenzene 1,2,40% 5% 5% Trimethylbenzene 1,3,50% 3% 2% Undecane, n3% 7% 7% Xylene, m,p20% 11% 7% Xylene, o7% 8% 5% Summarized in Table 3, the highest percenta ge of detections in the outdoor air in the 0 – 6 feet thick Vadose Zone sample se t for chemicals were toluene, m,p-xylene, benzene, ethylbenzene, and o-xylene, respectiv ely. The highest percentage of detections in the indoor air in the 0 – 6 feet thick Vadose Zone sample set for chemicals were oxylene, toluene, benzene, m,p-xylene, ethylbenzene, n-decane, and n-undecane respectively. The highest per centage of detections in soil vapor in the 0-6 feet thick Vadose Zone sample set for chemicals were toluene, benzene, carbon disulfide, n-decane, m,p-xylene, and n-unde cane, respectively. Table 3. Frequency of Detected Chem icals for 06 feet Vadose Zone 0-6 feet Vadose Zone Frequency of Detection Frequency of Detection Frequency of Detection Chemical Name Outdoor Air Indoor Air Soil Vapor Benzene 13% 8% 10% Benzothiophene 0% 0% 1%

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10 Table 3.(continued) Carbon disulfide 1% 2% 7% Decane, n6% 7% 7% Dodecane, n6% 6% 5% Ethylbenzene 7% 7% 6% Ethylthiophene, 20% 0% 0% Indan 1% 2% 2% Indene 0% 0% 3% Methylnaphthalene,10% 2% 1% Methylnaphthalene,21% 3% 2% Methylthiophene, 20% 0% 0% Methylthiophene, 30% 0% 0% Naphthalene 1% 3% 4% Nonane 4% 5% 5% Styrene 1% 3% 4% Tetramethylbenzene1,2,4,50% 2% 2% Thiophene 1% 0% 1% Toluene 16% 10% 11% Trimethylbenzene 1,2,34% 3% 4% Trimethylbenzene 1,2,46% 6% 5% Trimethylbenzene 1,3,53% 3% 2% Undecane, n4% 7% 7% Xylene, m,p13% 10% 7% Xylene, o7% 8% 5% As summarized in Table 4 the highest per centage of detections in the outdoor air in the 625 feet thick Vadose Zone sample se t for chemicals were toluene, m,p-xylene, oxylene, benzene, n-decane, 1,2,4-trimethylbenzene, and n-undecane respectively. The highest percentage of detections in the i ndoor air in the 625 f eet thick Vadose Zone sample set for chemicals were benzene, ndecane, n-dodecane, ethylbenzene, nonane, toluene, n-dodecane, m,p-xylene, and o-xylene, respectively. The highest percentage of

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11 detections in soil vapor in the 625 feet th ick Vadose Zone sample set for chemicals were toluene, m,p-xylene, n-undecane, nonane, 1,2,4,5-tetramethylbenzene, ethylbenzene, ndecane, n-dodecane, and naphthalene respectively. Table 4. Frequency of Detected Chemicals for 6 – 25 feet Vadose Zone 6-25 feet Vadose Zone Frequency of Detection Frequency of Detection Frequency of Detection Chemical Name Outdoor Air Indoor Air Soil Vapor Benzene 9% 7% 5% Benzothiophene 0% 0% 0% Carbon disulfide 0% 1% 3% Decane, n9% 7% 6% Dodecane, n6% 7% 6% Ethylbenzene 6% 7% 6% Ethylthiophene, 20% 0% 0% Indan 0% 2% 4% Indene 0% 0% 1% Methylnaphthalene,10% 2% 3% Methylnaphthalene,26% 3% 4% Methylthiophene, 20% 0% 0% Methylthiophene, 30% 0% 0% Naphthalene 3% 5% 6% Nonane 6% 7% 6% Styrene 0% 4% 5% Tetramethylbenzene 1,2,4,50% 3% 6% Thiophene 0% 0% 0% Toluene 11% 7% 7% Trimethylbenzene 1,2,36% 5% 5% Trimethylbenzene 1,2,49% 6% 5%

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12 Table 4.(continued) Trimethylbenzene 1,3,50% 2% 4% Undecane, n9% 7% 6% Xylene, m,p11% 7% 7% Xylene, o11% 7% 5% Risk Assessment Guidelines The National Research Council defines risk assessment as the characterization of the potential adverse health effects of huma n exposures to environmental hazards (NRC, 1983). In addition risk assessment includes th e potential for health effects based on an evaluation of results of epidemiologic, clinic al, toxicologic, and environmental research; extrapolation from those results to predict th e type and estimate the extent of health effects in humans under given conditions of exposures; judgments as to the number and characteristics of persons exposed at vari ous intensities and durations; and summary judgments on the existence and overall magnit ude of the public-health problem. Risk assessment also includes characterization of th e uncertainties inherent in the process of inferring risk (NRC, 1983). The USEPA and other federal and state agencies have developed risk assessment guidelines c onsistent with those of the NRC. Sources used for this risk assessment include the USEPA’s Integrated Risk Information System (IRIS), the National Toxicology program (NTP ), the Agency for Toxic Substances and Disease Registry (A TSDR), and the International Agency for Cancer Research (IARC). Integrated Risk Information System (IRIS). The Integrated Risk Information System (IRIS), prepared and maintained by the EPA’s National Center for Environmental

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13 Assessment (NCEA), is an electronic databa se containing information on human health effects that may result from exposure to va rious substances in the environment (EPA, 2008). Originally designed for internal use by the U.S. EPA, IRIS is now a publicly available repository of hea lth effects information on over 500 chemicals found in the environment (Persad et al., 2008). This inform ation database contains descriptive and quantitative information for both non-cancer a nd cancer effects of s ubstances. The term “substances” is used to include chemical s, and other forms of hazardous materials including radiation and biological agents. Fo r non-cancer effects oral reference doses (RfDs) and inhalation reference concentrati ons (RfCs) are devel oped generally for the non-carcinogenic effects of substances. Both RfCs and RfDs are estimates of daily exposure that are likely to be without an a ppreciable risk of a ny adverse effect over a lifetime (Persad et al., 2008). The USEPA developed weight-of-evidence (W OE) used to describe a substance’s potential to cause cancer in humans and the conditions under which the carcinogenic effects may be expressed. In the past th e USEPA utilized categories A through E to describe carcinogenic risk of substances. Since 2005, the USEPA has utilized a narrative approach to characterize carci nogenicity. Five standard weig ht-of-evidence descriptors Carcinogenic to Humans, Likely to Be Carc inogenic to Humans, Suggestive Evidence of Carcinogenic Potential, Inadequate Informati on to Assess Carcinogenic Potential, and Not Likely to Be Carcinogenic to Humans are now used to characterize carcinogenicity (IRIS, 2008). The USEPA has also developed cancer sl ope factors (ingestion) and unit risks (inhalation) used to estimate th e risk of cancer associated with exposure to a carcinogenic

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14 or potentially carcinogenic substance. The slope factor is an upper bound estimate, approximating a 95% confidence limit, on the increased cancer risk from a lifetime exposures to an agent by i ngestion generally expressed in units of proportion (of a population) affected per mg of substance/kg body weight-day. A unit risk is an upperbound excess lifetime cancer risk estimated to result from continuous exposure to an agent at a concentration of 1 g/L in water or 1 g/m3 in air (IRIS, 2008). National Toxicology Program (NTP). This federal agency, found in the National Institutes of Health (NIH) in the United Stat es Department of Health and Human Services (DHHS), evaluates agents of public health concern and publishes a biennial report known as the Report on Carcinogens (RoC). This report contains a list of all known human carcinogens or reasonably be anticipated to be human carcinogens to which a significant number of persons residing in the United St ates are exposed. The RoC does not present quantitative assessment of the risks of cancer nor the exposur e conditions associated with these substances (NTP, 2005). Agency for Toxic Substances and Disease Registry (ATSDR) The ATSDR, another agency of the DHHS located in the Center for Disease C ontrol and Registry, by congressional mandate, has specific functions concerning the effect on public health of hazardous substances in the environment. ATSDR publishes minimum risk levels (MRLs) for many hazardous substances. The MRLs are estimates of exposure levels for substances that are estimated to be without an appreciable risk of adverse health effects over a specified duration (ATSDR, 2008). International Agency for Research on Cancer (IARC). A branch of the World Health Organization, IARC conducts resear ch on environmental carcinogens and

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15 established strength of evidence categories for them. This strength of evidence categories are: Group 1A Carcinogenic to Humans (105 agents) ; Group 2A Probably Carcinogenic to Humans (66 agents) ; Group 2B Possibly Carcinogenic to Humans (248 agents) ; Group 3 not classifiable as to its carci nogenicity to humans (515 agents); and Group 4 probably not carcinogenic to humans (1 agent) (IARC, 2008). Based on the frequency of detection in the sample groups, the assessment of public health risks from potential soil vapor intrusion from former MGP sites will be conducted on the five chemicals with the highe st level of detections : benzene, toluene, ethylbenzene, m,p-xylene, and o-xylene. Benzene (Benzol, phenyl hydride, CAS #71-43-2). Benzene is a colorless to lightyellow liquid with an aromatic odor (NIOSH 2003, 2005). It is used as a gasoline additive, and can be found in cigarette sm oke, petroleum, and as a consequence of biomass combustion. It is also found to occu r naturally in some foods (Harbison 1998). Benzene is found in the air from emissions from burning coal and oil, gasoline service stations, and motor vehicle exhaus t (EPA, 2000). Benzene was first discovered and isolated from coal ta r in the 1800s but today, ben zene is made mostly from petroleum. Because of its wide use, benzene ranks in the top 20 in production volume for chemicals produced in the United States (A TSDR, 2007). Natural sources of benzene, which include gas emissions from volcanoes a nd forest fires, also contribute to the presence of benzene in the environment (ATSDR, 2007). Benzene is readily absorbed via inhalation with about 40-50% retained. It is taken up preferentially by fatty and nervous tissu es, and about 30-50% is excreted unchanged via exhalation. Epidemiologic studies and case studies provid e clear evidence of a causal

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16 association between exposure to benzene and acute nonlymphocytic leukemia and also suggest evidence for chronic nonlymphocytic leukemia and chronic lymphocytic leukemia. Other neoplastic conditions that are associated with an increased risk in humans are hematologic neoplasms, blood diso rders such as preleukemia and aplastic anemia, Hodgkin's lymphoma, and myel odysplastic syndrome (NLM, 2005). The majority of benzene metabolism occurs in th e liver, but the bone marrow is the target organ where its toxicity is expressed w ith the greatest sensitivity (EPA, 2002). Acute effects of benzene exposure incl ude irritation of mucous membranes, restlessness, convulsions, excitement, depres sion and even death due to respiratory failure. The major toxic effect of benzene is its hematopoietic toxicity (Khan, 2007). Benzene has been shown to produce neurotox ic effects in experimental animals and humans after short-term exposures to re latively high concentrations of the compound. Benzene produces generalized symptoms su ch as dizziness, headache, and vertigo, leading to drowsiness, tremor, delirium, and loss of consciousness (EPA, 2002). Benzene is characterized as a known huma n carcinogen for all routes of exposure based upon convincing human evidence as we ll as supporting evidence from animal studies (EPA, 2003). To date, only benzene, ha s utilized human data for derivation of all three quantitative risk estimates (i.e., RfC, RfD, and dose-response modeling for cancer assessment)(Persad et al., 2008). The RfC for established for benzene is 3 x 10-2 mg/m3 (EPA, 2005). The unit risk factor, expressed as a range, is 2.2 x 10-6 to 7.8 x 10-6, the increase in the lifetime risk of an indivi dual who is exposed for a lifetime to 1 g/m3 benzene in air (EPA, 2000).

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17 Toluene (methylbenzene, toluol, CAS # 108-88-3 ). Toluene is a clear, colorless liquid with a distinctive smell. Toluene occurs na turally in crude oil and in the tolu tree. It is also produced in the process of making ga soline and other fuels from crude oil and making coke from coal. Toluene is used in making paints, paint thinners, fingernail polish, lacquers, adhesives, and rubber and in some printing and leather tanning processes (ATSDR, 2008a). Acute exposures to toluene may cause di zziness, headache, lethargy, inebriation, exhilaration, drowsiness, st aggering gait, nausea, and CNS depression. Over 200 ppm, effects are more pronounced including di lated pupils, insomnia, and poor light accommodation. High concentrations lead to collapse, coma, and death (Harbison, 1998). Observed effects include reversible neurological symptoms from acute exposure progressing from fatigue, headache, and decr eased manual dexterity to narcosis with increasing exposure level, degenerative cha nges in white matter in chronic solvent abusers, and subtle changes in neurol ogical functions including cognitive and neuromuscular performance, hearing, and co lor discrimination in chronically exposed workers (ATSDR, 2000). In humans, respirat ory tract irri tation is experienced from exposure to toluene. Cardiac arrhythmia is a cause of death that has been associated with some solvent abuse fatalities. However, st udies in laboratory animals do not provide convincing support for a direct effect of toluene on the ca rdiovascular system (ATSDR, 2000). No studies examining the chronic or subchronic effects of oral exposure to toluene in humans are available (EPA, 2005). Eleven human epidemiology studies were located that assesse d toluene exposure as a possible risk factor for cancer. Can cers of most sites were not significantly

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18 associated with toluene exposure in any st udy and there was weak consistency in the findings of those studies that did find association of a partic ular cancer type with toluene exposure. Eleven human epidemiology studi es were located that assessed toluene exposure as a possible risk f actor (ATSDR, 2000). Under the Guidelines for Carcinogen Risk Assessment (EPA, 2005), there is inadequate informati on to assess the carcinogenic potential of toluene because studies of humans chronically exposed to toluene are inconclusive, toluene was not car cinogenic in adequate inhala tion cancer bioassays of rats and mice exposed for life for cancer (EPA, 2005) Cancers of most sites were not significantly associated w ith toluene exposure in any study and there was weak consistency in the findings of those studies that did find association of a particular cancer type with toluene exposure(ATSDR, 2000 ). The RfC established for toluene is 5 mg/m3 (EPA, 2005). Ethylbenzene (Ethylbenzol, CAS # 100-41-4). Ethylbenzene is a colorless liquid with an aromatic odor. Ethylbenzene is an ar omatic hydrocarbon that occurs naturally in petroleum and is a component of aviation and automotive fuels. Ethylbenzene is widely distributed in the environment. It is primarily used for the production of styrene, which is the monomeric unit for polystyrene materials. Ethylbenzene is also used as a solvent and in the manufacture of several organic compounds other than styrene; however, these uses are very minor in comparison to the am ounts used for styrene production (ATSDR, 2007a). Routine human activities, such as driving au tomobiles, boats, or aircraft, or using gasoline powered tools and equipment, re lease ethylbenzene to the environment. Environmental and background levels of ethylbe nzene are generally small and therefore,

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19 have minimal impact on public health. Trace levels of ethylbenzene are found in internal combustion engine exhaust, food, soil, water, and tobacco smoke, but usually at levels well below those that have been shown to exhi bit toxic effects in la boratory animals or human exposure studies (ATSDR, 2007a). Et hylbenzene in air is broken down in less than 3 days with the aid of sunlight (EPA, 1991). The production volume of ethylbenzene is typically among the highest of all chemicals manufactured in the United St ates. In 2005, nearly 12 billion pounds of ethylbenzene were produced dom estically, with historical le vels ranging anywhere from approximately 7 to 13 billi on pounds annually (ATSDR, 2007a). There are currently 3,558 fac ilities that produce, process, or use ethylbenzene in the United States (ATSDR, 2007). Unfractiona ted crude oil contai ns 1–2.5% by weight of C6–C8 aromatics, mainly toluene, the xylenes and ethylbenzen e, and oil refining therefore is also likely to re sult in exposures. Ethylbenzene has been detected in bitumen fumes during road paving. Another source of occupational exposure to ethylbenzene is the production and handling of gasoline and other fuels in which it is a component (IARC, 2000). Exposure to high levels of ethylbenzene in the air for short periods can cause eye and throat irritation. Exposure to higher le vels can result in vertigo and dizziness. Ethylbenzene is primarily an irritant to th e skin and mucous membranes and possesses narcotic properties at high concentrations (Fishbein, 1985a). No studies were located regarding lethality in humans following i nhalation exposure to ethylbenzene (ATSDR, 2007a). Long-term biomonitoring of occupationa l ethylbenzene exposur es, carried out in the past 20 years in some 200 ethylbenzene-pr oduction workers, revealed this substance

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20 to pose little hazard to human health (Bardod j, et al, 1988). The RfC established for ethylbenzene is 1 mg/m3 (EPA, 1991). Ethylbenzene is considered not classifiable as to human carcinogenicity (EPA, 1991). Xylene Isomers (Xylenes, CAS # 1330-20-7 meta-Xylene, CAS # 108-38-3) (paraXylene, CAS # 106-42-3)(ortho-Xylene, CAS # 95-47-6). Xylene isomers are clear, colorless liquids with a sweet aroma. Comm ercial or mixed xylene generally contains about 40–65% m -xylene and up to 20% each of o -xylene, p -xylene, and ethylbenzene (ATSDR, 2007b). It is produced in very large quantities and is ex tensively employed in a broad spectrum of applications, primarily as a solvent for which its use is increasing as a "safe" replacement for benzene, and in gasoli ne as part of the BTX component (benzenetoluene-xylene); xylenes are also frequently used in the rubber industry with other solvents such as toluene and benzene (Fishbe in, 1985). Xylene is a common ingredient in paints with some containing greater th an 50% xylenes (Harbison, 1998). U.S. manufacturers had an estimated annual pr oduction capacity of 18 billion pounds of mixed xylene in 2006 (SRI 2006). According to da ta collected under the Toxic Substances Control Act Inventory Update Rule, the total production volu me of mixed xylene reported by U.S. manufactur ers has remained above 1 billion pounds during each reporting year (ATSDR, 2007b). As individual isomers they are extensivel y employed in the synthesis of synthetic agents, for example phthalic acid, isopht halic acid, terephthalic acid and dimethylterephthalate, which have very broad applications in the fu rther preparation of phthalate ester plastici zers and components of polyester fi ber, film and fabricated items. There is a broad potential for exposure both to industrial worker s in the production and

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21 use of the xylenes and to the general public (via vehicle exhausts, consumer products, etc) (Fishbein, 1985). Approxima tely 70% of mixed xylene is used in the production of ethylbenzene and the m, o, and pisomers. The remaining mixed xylene is used as a solvent, in products such as paints and coatings, or bl ended into gasoline (ATSDR, 2007b). Xylene vapor is absorbed rapidly from the lungs, and xylene liquid and vapor are absorbed slowly through the skin (Langma n, 1994). High levels of xylene exposure can cause polyuric renal failure, re spiratory failure, hemorrhages, and necrosis in the brain, liver kidneys, and heart (Harbison, 1998). Xy lene in high concentrations acts as a narcotic, inducing neuropsychological and neurophysiological dysfunction. Respiratory tract symptoms are also frequent. More chronic, occupational exposure has been associated with anemia, thrombocytopenia, leukopenia, chest pain with ECG abnormalities, dyspnea and cyanosis, in addition to CNS symptoms (Langman, 1994). Chronic occupational exposure of worker s to an unspecified concentration of vapors of mixed xylene has also been associ ated with labored breathing and impaired pulmonary function (ATSDR, 2007b). A crosssectional study perf ormed in shipyard painters exposed to with solvent-based pa ints containing > 50% xylene found decreased peripheral nerve function (R uijten, et al., 1994). The RfC for non-carcinogenic health e ffects established for xylenes 0.1 mg/m3 (EPA, 2003a). Xylenes refer to mixtures of all three xylene isom ers and ethylbenzene. The inhalation RfC for xylenes is based on a principal study in which rats were exposed by inhalation to m-xylene. There was some uncertainty associated with selecting a principal study for xylenes that involved expos ure to m-xylene alone, but this isomer is

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22 generally predominant in commercial mixtures (EPA, 2003a). IRIS classifies xylenes as data are inadequate for an assessmen t of the carcinogenic potential Adequate human data on the carcinogenicity of xylenes are not available, and the available animal data are inconclusive as to the ability of xylenes to cause a carcinogenic response. Evaluations of the genotoxic effects of xylenes have cons istently given negative results (EPA, 2003a). The RfCs, unit risk factors, and weight of evidence, as listed by EPA’s IRIS, for each chemical discussed above are summari zed on Tables 5 through 7. The term “ point of departure ” (POD) used in Table 5 marks the beginning of extrapolation to lower doses. The POD is an estimated dose (usually expressed in human-equivalent terms) near the lower end of the observed range, without significant extrapolation to lower doses (EPA, 2005a). Table 5. Inhalation Reference Concentration (RfC) Summary Inhalation Reference Concentrations Substance CASRN Critical Effects Inhalation RfC Point of Departure* Overall Confidence Benzene 71-43-2 Decreased lymphocyte count 3x10-2 mg/m3 BMCL : 8.2 mg/m3 Medium Ethylbenzene 100-41-4 Developmental toxicity 1 mg/m3 NOAEL (HEC): 434 mg/m3 Low Toluene 108-88-3 Neurological effects in occupationallyexposed workers (other effect: ) 5 mg/m3 NOAEL (ADJ): 46 mg/m3 High

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23 Table 5. (continued) Xylenes 1330-20-7 Impaired motor coordination (decreased rotarod performance) 0.1 mg/m3 NOAEL (HEC): 39 mg/m3 Medium Source: IRIS, 2008. *The Point of Departure listed serves as a basis from which the Inhalation RfC was derived. CASRN – Chemical Abstract Service Registry Number BMCLBenchmark Concentration Level HEC – Human Equivalence Concentration NOAELNo Observable Adverse Effects Level Table 6. Inhalation Unit Risk (IUR) Summary Inhalation Unit Risks Substance CASRN Precursor Effect/ Tumor Type Extrapolation Method Inhalation Unit Risks Study Route Benzene 71-43-2 Leukemia Low-dose linearity utilizing maximum likelihood estimates 2.2x10-6 per ug/m3 1 Inhalation Low-dose linearity utilizing maximum likelihood estimates 7.8x10-6 per ug/m3 1 Ethylbenzene 100-414 Not Assessed under the IRIS program. Toluene 108-883 Not Assessed under the IRIS program. Xylenes 133020-7 Not Assessed under the IRIS program. CASRN – Chemical Abstract Service Registry Number

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24 Table 7. Weight of Evidence (WOE) Information Summary Weight-of-Evidence Characterizations Substance CASRN WOE 86 Guidelines WOE Narrative Benzene 71-43-2 A, Human Carcinogen Under the proposed revised Carcinogen Risk Assessment Guidelines (U.S. EPA, 1996), benzene is characterized as a known human carcinogen for all routes of exposure based upon convincing human evidence as well as suppor ting evidence from animal studies. (U.S. EPA, 1979, 1985, 1998; ATSDR, 1997). Ethylbenzene 100-41-4 D, Not classifiable as to human carcinogenicity Nonclassifiable due to lack of animal bioassays and human studies. Toluene 108-88-3 D, Not classifiable as to human carcinogenicity No human data and inadequate animal data. Toluene did not produce positive results in the majority of genotoxic assays. Xylenes 1330-207 NA, Not applicable. This substance was not assessed using the 1986 cancer guidelines (U.S. EPA, 1986). Under the Draft Revised Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1999), data are inadequate for an assessment of the carcinogenic potential of xylenes. Adequate human data on the carcinogenicity of xylenes are not available, and the available animal data are inconclusive as to the ability of xylenes to cause a carcinogenic response. Evaluations of the genotoxic effects of xylenes have consistently given negative results.

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25 Chapter Three Methods and Materials Study Description This study evaluated the potential fo r SVI for properties overlying and immediately abutting MGP tar source material and properties overlying and adjacent to dissolved phased benzene, toluene, ethyl benzene and xylene (BTEX) and naphthalene plumes emanating from the MGPs. A tota l of 10 commercial and 26 single family and multi-family residential properties associated with the three former MGPs were evaluated for potential SVI of MG P-related chemicals. Each of the sites included in this study were located in the northeastern US. Further evaluation of the potential for SVI exposure was conducted to evaluate whether depth to groundwater influenced th e potential for SVI by categorizing each of the sites into three groupings according to dept h to the water table: no vadose zone; water table within 6 feet of the building slab; a nd water table between 6 and 25 feet of the building slab. In addition, comparative risk assessment s were conducted on the five chemicals with the highest frequency of detection in the indoor air and soil vapor of the sampled buildings, and the outdoor air near these st ructures. The chemicals with the highest frequency of detection were benzene, tolu ene, ethylbenzene, m,p-xylene, and o-xylene (See Tables 2 through 4). For benzene, a known human carcinogen (NTP, 2005), cancer

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26 risk calculations were computed for the m ean and maximum concentrations of benzene detected in the sample groups. For th e non-carcinogenic chem icals, toluene, ethylbenzene, m,p-xylene, and o-xylene, h azard indices were calculated for both the mean and maximum concentrations detected in the sample groups. HQs were also calculated for benzene. Vapor Intrusion is the migration of volat ile chemicals from the subsurface into overlying buildings (EPA, 2002a). Prior to cond ucting a soil vapor intrusion assessment for a private property, an analysis of the f actors contributing to the migration of soil vapor to indoor air was conducted. Factors that could influence the result s of the soil vapor assessment included environmental factors and building factors. En vironmental factors included site specific conditions in the subsurface and abovegr ound surface that may affect the rate and direction at which soil vapor may migrate. Evaluation of the potential for SVI exposure was conducted to evaluate whether depth to gr oundwater influenced the potential for SVI by categorizing each of the former MGP sites into three groupings according to depth to the water table: no vadose zone; water table w ithin 6 feet of the bu ilding slab; and water table between 6 and 25 feet of the building slab. Building factors included the physical characteristics, such as structure, floor layout, air flow and physical conditions. The soil and groundwater conditions be tween the contamination and the residential/ commercial building were evaluated to identify the potential for man-made or natural preferential pathways for vapor mi gration in the vadose zone and/or for groundwater migration. Additiona l environmental factors evaluated included the depth to groundwater and the direction of groundwater flow from the contaminant source to the

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27 residential or commercial bu ilding; the location, depth, ex tent and concentration of potential MGP-related constituents in unsatur ated soil and groundwater on the property; the presence of an overlying water bearing zone not containing MGP impacts; and if present, the location, depth, and extent of potential “smear zones” (residual NAPL present at depths over which th e water table fluctuates). Building factors that could influence indoor air quality include the use or storage of petroleum-based household chemical produc ts or those containi ng volatile organic compounds (VOCs); the use of home heati ng oil storage tanks, underground storage tanks (USTs) or kerosene heaters; and recen t renovations to the building such as new paint or new carpet. The use or presence of these chemicals or products could be a confounder in the evaluation of potential MGP impacts on indoor air quality. According to the EPA, a complicating fact or in evaluating th e potential chronic risk from vapor intrusion is the potential pres ence of some of the same chemicals at or above background concentrations (from the am bient outdoor air and/or emission sources in the building e.g., household solvents, gasoline cleaners) that may pos e separately or in combination with vapor intrusion, a signifi cant human health risk (EPA, 2002a). The mere presence of a chemical in both the subsurface and indoor air is in general insufficient to establish that linkage, give n the high potential for other above-ground and indoor sources of many volatile organic chemicals of inte rest (Johnson, et al., 2002). To this end, a pre-assessment building survey and chemical inventory was conducted to identify and record the pres ence of these factors. In addition to the use of products that coul d influence air quality, an assessment of the building foundation constructi on characteristics (basement, footers, crawl spaces, etc)

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28 was conducted to identify potential preferen tial vapor intrusion pathways such as foundations cracks and utility penetrations. Heating system s, including fireplaces and clothes dryers, were identified since their use could create a pressure differential between the structure and the outside environment, cau sing an increase of mi gration of soil vapor into the building. For each property evaluated indoor air sa mples and outdoor ambient air samples were collected with Summa or equivalent can isters. In property sett ings where a vadose zone was present beneath the building slab, su b-slab soil vapor samples were collected. Where the water table was present above a bui ldings basement slab, soil vapor samples were collected beneath a surrogate cap (pati o, driveway, etc.) at an elevation above the basement slab; and in the property settings where no vadose zone was present (water table within 6-inches of the land surface) only indoor air samples were collected. For quality assurance purposes, a helium tracer gas was utilized to evaluate the integrity of the soil vapor probe seal and as sess the potential for in troduction of outside air into the soil vapor sample. Figure 1. Example of Collecti on of Indoor Air Samples usi ng Summa or equivalent canisters

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29 Figure 2. Example of Collecti on of Soil Vapor Sample from a Temporary Soil Vapor Point using a Summa or equivalent canister The samples were collected in accordance with federal and state regulatory recommended sampling procedures. An approve d laboratory was utilized to analyze all air samples, including the sub-sl ab or soil vapor samples. All samples were analyzed for VOCs by the United States Environmental Protection Agency (USEPA) Method TO-15 plus naphthalene. The vapor intrusion asse ssments focused on those volatile chemicals that are potentially MGP related, however th e TO-15 analytical method used to assess indoor air quality included many chemicals that are not MGP-related but are commonly evaluated when assessin g indoor air quality. To analyze an air sample using Method TO-15, a known volume of sample is directed from the canister through a solid mu ltisorbent concentrator. A portion of the water vapor in the sample breaks through th e concentrator during sampling, to a degree depending on the multisorbent composition, duration of sampling, and other factors. Water content of the sample can be further reduced by dry purging th e concentrator with helium while retaining target compounds. Af ter the concentration and drying steps are completed, the VOCs are thermally desorbed, en trained in a carrier gas stream, and then

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30 focused in a small volume by trapping on a reduced temperature trap or small volume multisorbent trap. The sample is then rele ased by thermal desorption and carried onto a gas chromatographic column for separation. The analytical strategy for Compendium Method TO-15 involves using a high resolution gas chromat ograph (GC) coupled to a mass spectrometer. Mass spectrometry is considered a more definitive identification technique than single specific detectors such as flame ionization detector (FID), electron capture detector (ECD), photoi onization detector (PID), or a multidetector arrangement of these (EPA, 1999). An independent data reviewer was us ed to perform data validation on all laboratory analytical results The data validation was based on the USEPA Contract Laboratory Program National Functional Guide lines for Organic Data Review, January 2005 (EPA, 2005b). The organic data were eval uated based on the following parameters: Data Completeness Holding Times and Sample Preservation Gas Chromatography/Mass Sp ectrometry (GC/MS) Tunes Initial and Continuing Calibrations Surrogate Recoveries Matrix Spike/Matrix Spike Duplicate (MS/MSD) Results Internal Standards Laboratory Control Sample (LCS) Results Quantitation Limits and Data Assessment Sample Quantitation and Compound Identification

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31 Risk Assessment This risk assessment followed the guidelines outlined in EPA’s Risk Assessment Guidance for Superfund (EPA, 1989). There are four steps to the risk assessment process: data collection and analysis; exposur e assessment; toxicity assessment; and risk characterization. Data collection and analysis involves gather ing and evaluating site data that will be the focus of the risk assessme nt. Indoor air, outdoor air, and soil vapor samples were collected from residents and bu ildings and analyzed for VOCs and SVOCs. This study identified five chemicals to be used in the risk assessment based on the frequency of detection in indoor ai r, outdoor air, and soil vapor. Exposure assessment estimates the ma gnitude, frequency, duration, and the potential pathways of exposure. This study fo cused on the potential pathway of soil vapor intrusion of chemicals into th e indoor air of residents and bu ildings and the potential risks associated with inhalation of these chemical s. Toxicity assessment considers potential adverse health effects associated with ch emical exposures; the relationship between magnitude of exposure and adverse effects; a nd the uncertainties such as the weight of evidence data. The health effects considered in this study are outlined in the previous section. Risk characterization summarizes and combines the data collected and used in the exposure assessment with the results of the toxicity assessme nt to characterize baseline risk to the occupants of buildings or residences adjacent to former MGP sites. Occupants of buildings and residences ad jacent to the former MGP sites were evaluated in this risk assessment. Th is population included adults and children. Comparisons of the indoor ai r, soil vapor, and outdoor ai r maximum and mean results

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32 categorized by vadose zone were made to the 95th percentile regulatory background concentrations for indoor and outdoor air. No data base is available for comparison of soil vapor concentrations; however it is generally acceptable practice to compare soil vapor data to indoor air bac kground levels if the soil vapor data is being evaluated for intrusion into the indoor ai r of a building structure. In addition, concentrations detected in the indoor air were compared to concentrations detected in soil vapor fo r each location. If soil vapor intrusion was occurring the concentration of chemicals in the soil vapor would be higher than those detected in the indoor air. Also, indoor air concentrations were compared to outdoor air concentrations to evaluate whether indoor air quality was influenced by chemicals detected in the outdoor air. To assess the overall potentia l for non-carcinogenic effects posed by more than one chemical, a hazard index (HI) approach was utilized (EPA, 1989). The HI approach presumes that simultaneous sub-threshold expos ures to several chemicals could result in an adverse health effect. HIs are sums of a non-cancer hazard quotient that assumes there is a level of exposure (i.e., RfC) below whic h it is unlikely for even sensitive populations to experience adverse health effects. Hazard quotients (HQs) were calculated by dividing the exposure concentration by the reference concentration. There may be a concern for potential non-carcinogenic effects if the HI is greater than 1 (EPA, 1989). Hazard Quotients (HQs) were calculated using the study results and the mean, maximum, and 95th percentile concentrations from regulatory data bases. HQs were calculated by dividing the mean, maximum and 95th percentile concentrations found in

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33 indoor air, outdoor air, and soil vapor by th e RfC. HIs were then calculated by summing the totals of the HQs for each chemical by media (i.e. indoor air, outdoor air, soil vapor). Carcinogenic risks associated with expos ure to benzene were calculated using both the measured mean and maximum st udy results and the mean, maximum and 95th percentile concentrations from state and fe deral data bases. The IUR for benzene is 2.210 6 to 7.810 6 (EPA, 2003). The IUR is based on a 70 kg adult breathing 20 m3 of air per day. Based on this IU R an individual exposed to 1 g/m3 benzene in air has an increased lifetime risk or IUR of 2.210 6 to 7.810 6 of developing leukemia. Cancer risks from inhalation of benzene were calculated by multiplying the concentrations in indoor air, outdoor air, and soil vapor by ben zene’s inhalation unit risk range. The EPA expresses the likelihood of cancer as a probabi lity, such as 1x10-6 or 1 in a 1,000,000 chance. This expression of probability means that for every 1,000,000 people, one excess cancer case may occur as a result of an exposure to a chemical. This one cancer case is in excess of the normal cancer cases expected fr om all other causes. This is an upper bound estimate of risk and the true risk could actua lly be zero. A generally acceptable range for cumulative excess cancer risk of 10-6 to 10-4 for protecting human health has been established by the EPA.

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34 Chapter Four Results Data was categorized into three groupings according to depth to the water table: no vadose zone; water table with in 6 feet of the building sl ab; water table between 6 and 25 feet of the building slab. Frequency of detection was determined for each compound analyzed and the five compounds with the hi ghest frequency of de tection identified (Tables 2-4). Benzene, toluene, ethylbenzene, m,p-xylene, and o-xylene had the highest frequency of detections of the study results. An alytical results of th e soil vapor intrusion assessments were directly compared to US federal and state background concentrations. The two comparative data bases used in this study as backgr ound values were the United States Environmental Protection Agency Building Assessment and Survey Evaluation (BASE 1994-1998) and the New York State Department of Health (NYSDOH ) Guidance for Evaluating Soil Vapor In trusion in the State of New York (2006). The USEPA BASE study included m easurement of VOCs, radon, formaldehyde, carbon monoxide, carbon dioxide, and particulat es in indoor air (Table 8) and outdoor air (Table 9) at 100 randomly selected public and commercial office buildings across the United States (EPA, 2001). Tables 8 and 9 summarize EPA background concentrations for benzene, toluene, ethylben zene, m,p-xylene, and o-xylene.

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35 Table 8. EPA 2001 Building Assessment a nd Survey Evaluation (BASE) Background Concentrations for Indoor Air (ug/m3) Indoor Air Compound Mean* Min 25th Median 75th 90th 95th 99th Max Benzene 4.5 <0.8 2.1 3.4 5.1 9.4 12.5 25.0 63.0 Ethylbenzene 2.8 <0.9 <1.6 1.4 3.4 5.7 7.6 18.5 73.6 Toluene 25.1 3.5 10.7 15.7 25.9 43.0 70.8 348.9 390.3 m,p-Xylene 10.8 <1.5 4.1 6.9 12.2 22.2 28.5 67.6 260.8 o-Xylene 3.8 <0.7 <2.4 2.4 4.4 7.9 11.2 20.1 90.5 Min Minimum concentration detected 25th – 25th percentile 75th – 75th percentile 90th – 90th percentile 95th95th percentile 99th99th percentile Max – Maximu m concentration detected Table 9. EPA 2001 Building Assessment a nd Survey Evaluation (BASE) Background Concentrations for Outdoor Air (ug/m3) Outdoor Air Compound Mean* Min 25th Median 75th 90th 95th 99th Max Benzene 3.2 <1.2 1.2 2.7 3.7 6.6 9.6 12.6 13.0 Ethylbenzene 1.4 <0.8 <1.4 <1.8 1.6 3.5 4.3 7.6 7.8 Toluene 15.4 2.1 5.9 9.6 16.3 33.7 49.2 86.5 93.1 m,p-Xylene 5.6 <1.4 <3.6 4.4 7.3 12.8 16.1 24.8 26.8 o-Xylene 2.0 <0.6 <1.4 1.4 2.6 4.6 6.0 9.6 11.1 Min Minimum concentration detected 25th – 25th percentile 75th – 75th percentile 90th – 90th percentile 95th95th percentile 99th99th percentile Max – Maximu m concentration detected

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36 The NYSDOH conducted a study of the occurr ence of VOCs in the indoor air of homes that heat with fuel oil. The purpose of the study was to characterize the indoor environment of fuel oil heated homes as a means of evaluating post clean-up conditions in residences affected by petroleum spills. The summary report was used to help characterize concentrations and establish “background” conc entrations of 69 compounds commonly found in the indoor and outdoor air of residential settings heated with fuel oil (NYSDOH, 2006). Tables 10 and 11 su mmarize NYSDOH background concentrations for benzene, toluene, ethylbenzen e, m,p-xylene, and o-xylene. Table 10. NYSDOH 2003 Study of Volatile Organi c Chemicals in Air of Fuel Oil Heated Homes (ug/m3) – Indoor Air INDOOR AIR Compound Mean* Min 25th Median 75th 90th 95th 99th Max Upper Fence Benzene 8.3 <0.25 1.1 2.1 5.9 15 29 120 460 13 Ethylbenzene 3.7 <0.25 0.4 1 2.8 7.3 13 26 340 6.4 Toluene 26 <0.25 3.5 9.6 25 58 110 300 510 57 m,p-Xylene 5.9 <0.25 0.5 1.5 4.6 12 21 46 550 11 o-Xylene 3.8 <0.25 0.4 1.1 3.1 7.6 13 32 310 7.1 MinMinimum concentration detected 25th – 25th percentile 75th – 75th percentile 90th – 90th percentile 95th95th percentile 99th99th percentile Max – Maximu m concentration detected Table 11. NYSDOH 2003 Study of Volatile Organi c Chemicals in Air of Fuel Oil Heated Homes (ug/m3) – Outdoor Air OUTDOOR AIR Compound Mean* Min 25th Median 75th 90th 95th 99th Max Upper Fence Benzene 1.9 <0.25 0.6 1.3 2.2 4.3 5.8 13 17 4.8

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37 Table 11. (continued) Ethylbenzene 0.8 <0.25 <0.25 <0.25 0.5 1.1 1.9 19 21 1.0 Toluene 11 <0.25 0.6 1.3 2.4 5.9 21 350 640 5.1 m,p-Xylene 0.8 <0.25 <0.25 <0.25 0.5 1.4 3.1 17 20 1.0 o-Xylene 0.7 <0.25 <0.25 <0.25 0.6 1.7 2.5 8.9 10 1.2 MinMinimum concentration detected 25th – 25th percentile 75th – 75th percentile 90th – 90th percentile 95th95th percentile 99th99th percentile Max – Maximu m concentration detected The soil vapor data for each location wa s categorized by thickness of the vadose zone and maximum indoor air and soil vapor concentrations. Ta ble 12 displays the maximum concentration for benzene in the indoo r air as compared to soil vapor at each location with no vadose zone. Soil vapor samp les were not collected at seven of the locations due to groundwater in contact with the building sla b. Twelve of the locations had higher concentrations of benzene in the soil vapor than in indoor air. Locations15, 20, 3, and 14 exceeded the EPA 95th percentile background concentration for benzene but were below DOH background. All of these loca tions had benzene in the indoor air well below background. The soil vapor concentratio n of benzene at Location 2 exceeded both the EPA and NYSDOH 95th percentiles for background indoor air; however the concentration of benzene in the indoor air for this locati on was well below background. Table 12. Maximum Concentrations of Benzen e in Indoor Air versus Soil Vapor for Locations with No Vadose Zone Maximum Concentrations of Benzene by Location for Indoor Air vs Soil Vapor (No Vadose Zone) (ug/m3) Location Indoor Air Soil Gas Location 8 0.61

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38 Table 12. (continued) Location 5 0.77 Location 4 0.79 Location 16 0.8 Location 19 0.8 Location 1 0.93 Location 12 1 Location 10 1.1 0.96 Location 7 0.58 1.2 Location 21 4.4 1.3 Location 9 0.69 1.8 Location 11 1.31 1.92 Location 6 0.64 2.6 Location 17 1.2 3 Location 13 1.69 3.14 Location 18 0.64 3.2 Location 15 1.1 14 Location 20 0.74 15 Location 3 1.2 18 Location 14 0.89 19 Location 2 0.7 58

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39 Benzene No Vadose Zone1 1.1 4.4 1.31 1.2 0.74 1.2 1.3 2.6 3.0 3.13.2 14.0 15.0 18.0 19.0 58.0 1.1 1.69 .7 .89 .64 .64 .69 .58 .93 .8 .61 .77.79 .8 1.9 1.2 1.8 .96 -5 5 15 25 35 45 55 65Location 8 Loca t i on 5 L o c at i on 4 L o c at i on 16 L o c at i o n 19 Location 1 L o c ation 12 L o c ation 10 L o c at i on 7 L o c at i on 21 Locat i on 9 L o cation 11 Location 6 L o c ation 17 L o c at i on 13 L o c at i on 18 L o c at i on 15 L o cation 20 Location 3 L o c ation 14 Loca t i on 2Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA95th %ile Figure 3. Maximum Concentration of Ben zene by Locations with No Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001

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40 Table 13 displays the maximum concentra tion for benzene in the indoor air as compared to soil vapor at each location with a 0 – 6 feet thick vadose zone. A soil vapor sample was not collected for Location 24. Only one out of 10 locations had a higher concentration of benzene in the indoor air than in the soil vapo r. As seen in Figure 4 all of the indoor air and soil vapor concentrati ons for benzene were well below both the EPA and NYSDOH 95th percentiles for background indoor air. Table 13. Maximum Concentrations of Benzen e in Indoor Air versus Soil Vapor for Locations with 0 6 Feet Vadose Zone Maximum Concentrations of Benzene by Location for Indoor Air vs Soil Vapor (06 feet Vadose Zone)(ug/m3) Location Indoor Air Soil Vapor Location 26 0.80.94 Location 22 2.11.1 Location 23 0.851.1 Location 27 0.761.2 Location 29 0.641.6 Location 32 0.692.2 Location 28 1.82.9 Location 31 2.35.9 Location 25 1.16.1 Location 30 1.38.2 Location 24 4.72

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41 Benzene 0-6 Feet Vadose Zone2.1 1.8 2.3 1.1 1.3 4.7 1.1 1.2 1.6 2.2 5.9 6.1 8.2 .8 .9 .8 .6.7 2.9 1.1 .94 0 5 10 15 20 25 30 35Lo c a t i o n 2 6 Locatio n 2 2 Locatio n 2 3 Lo cat i o n 2 7 Lo cat i o n 2 9 Lo cat i o n 3 2 Location 2 8 Location 3 1 Lo cat i o n 2 5 Lo catio n 3 0 Location 24Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th %ile Figure 4. Maximum Concentration of Benzene by Locations with 0 – 6 feet Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001

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42 Table 14 displays the maximum concentra tion for benzene in the indoor air as compared to soil vapor at each location with a 6 – 25 feet thick vadose zone. Three out of the 4 locations had higher concentr ations of benzene in the soil vapor than in indoor air. As seen in Figure 5 all of the indoor air a nd soil vapor concentrations for benzene were well below both the EPA and NYSDOH 95th percentiles for background indoor air. Table 14. Maximum Concentrations of Benzen e in Indoor Air versus Soil Vapor for Locations with 6 25 Feet Vadose Zone Maximum Concentrations of Benzene by Location for Indoor Air vs Soil Vapor (625 feet) (ug/m3) Location Indoor Air Soil Vapor Location 34 2.80.99 Location 35 0.993.1 Location 36 2.83.2 Location 33 1.66.6 Benzene 6-25 Feet Vadose Zone2.82.8 1.6 3.13.2 6.6 .99 .99 0 5 10 15 20 25 30 35Lo cat ion 3 4 Lo cat ion 3 5 Location 36 Location 33Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA95th %ile Figure 5. Maximum Concentration of Benzene by Locations with 6 -25 feet Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001

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43 Table 15 displays the maximum concentra tion for toluene in the indoor air as compared to soil vapor at each location with no vadose zone. Soil vapor samples were not collected at seven of the locat ions due to groundwater in co ntact with the building slab. Seven of the locations had higher concentrations of toluene in the i ndoor air than in the soil vapor. One location had e qual concentrations of toluen e in the indoor air and soil vapor. Six of the locations had higher concentrat ions of toluene in the soil vapor than in indoor air. As seen in Figure 6 three locat ions, 15, 9, and 4, had to luene concentrations above the EPA 95th percentile for background indoor air. Locations 9 and 4 exceeded both 95th percentile background concen trations for toluene in i ndoor air. According to the questionnaire conducted at the time of sampling Locatio n 9 had recently painted and Location 4 recently used solvents. In addition, groundwater monitoring informa tion was researched to determine the potential source of toluene in the soil vapor at Location 9. Toluene was either non-detect or at very low concentrations in the groundwater near this location and therefore could not be the source of toluene. It was concl uded the recent painting activities accounted for the high concentrations of toluene. Table 15. Maximum Concentrations of Toluen e in Indoor Air versus Soil Vapor for Locations with No Vadose Zone Maximum Concentrations of Toluene by Location for Indoor Air vs Soil Vapor (No Vadose Zone) (ug/m3) Location Indoor Air Soil Vapor Location 10 6.20.92

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44 Table 15.(continued) Location 18 2.51.2 Location 7 2.21.3 Location 6 2.11.5 Location 17 3.72.6 Location 21 4.26.6 Location 3 136.7 Location 15 1007.2 Location 20 7.87.8 Location 14 3.48.4 Location 11 4.639.49 Location 13 5.7214 Location 2 1015 Location 9 220430 Location 1 37 Location 4 190 Location 5 1.8 Location 8 3.7 Location 12 4.6 Location 16 3.8 Location 19 2.8

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45 Toluene No Vadose Zone6.2 2.52.22.1 3.74.2 7.8 3.4 4.65.7 1.8 3.7 4.6 3.8 2.8 430 37 190 220 100 13 10 15 14 9.5 8.4 7.8 7.2 .92 6.6 1.2 1.31.52.66.7 0 50 100 150 200 250 300 350 400 450L ocation 1 0 L oca t ion 1 8 L oc at i on 7 L oc at ion 6 L oc at ion 1 7 L oc at ion 2 1 Loc at ion 3 L o cati on 1 5 L o cati on 2 0 L o cati on 1 4 Location 11 L ocation 13 Location 2 Location 9 Lo c at i on 1 Lo c at i on 4 L oc at ion 5 L oc at i on 8 L oc at ion 1 2 L oc at ion 1 6 L o cation 1 9Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th %ile Figure 6. Maximum Concentration of Tolu ene by Location with No Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001

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46 Table 16 displays the maximum concentra tion for toluene in the indoor air as compared to soil vapor at each location with 0-6 feet thick vadose zone. A soil vapor sample was not collected for Location 24. Te n locations had higher concentrations of toluene in the indoor air than in soil vapor. As seen in Figure 7 none of the locations with 0-6 feet thick vadose zones exceeded either the EPA or NYSDOH 95th percentiles for background indoor air for toluene. Table 16. Maximum Concentration of Toluene by Location with 06 feet Vadose Zone Maximum Concentrations of Toluene by Location for Indoor Air vs Soil Vapor (0 -6 feet)(ug/m3) Location Indoor Air Soil Vapor Location 23 2.60.86 Location 29 9.81.2 Location 27 2.71.3 Location 26 2.61.9 Location 32 5.71.9 Location 25 9.23.3 Location 22 124.6 Location 31 7.75.2 Location 30 8.36 Location 28 7.46.3 Location 24 10.7

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47 Toluene 0-6 Feet Vadose Zone2.6 9.8 2.72.6 5.7 9.2 12 7.7 8.3 10.7 1.21.3 1.91.9 3.3 4.6 5.2 6 6.3 7.4 .86 0 20 40 60 80 100 120L o cation 23 L o cation 29 Location 27 Loca t ion 26 Loca t ion 32 L oca t ion 2 5 L oca ti on 2 2 L oca ti on 3 1 L oca ti on 3 0 L o cati o n 28 L o cati o n 24Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th %ile Figure 7. Maximum Concentration of Toluene by Locations with 06 feet Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001 Table 17 displays the maximum concentra tion for toluene in the indoor air as compared to soil vapor at each location with a 6-25 feet thick vadose zone. Three out of the 4 locations had higher concen trations of toluene in the in door air than in soil vapor. As seen in Figure 8 all of the indoor air co ncentrations for toluene were well below both the EPA and NYSDOH 95th percentiles for b ackground indoor air.

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48 Table 17. Maximum Concentration of Toluene by Locations with 6 -25 feet Vadose Zone Maximum Concentrations of Toluene by Location for Indoor Air vs Soil Vapor (6 25 feet) (ug/m3) Location Indoor Air Soil Vapor Location 34 6.71.8 Location 35 99.6 Location 36 3110 Location 33 7.912.9 Toluene 6-25 Feet Vadose Zone6.7 9 31 7.9 1.8 9.610 12.9 0 20 40 60 80 100 120Lo cat ion 3 4 Locati o n 3 5 Location 36 L ocati on 3 3Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th %ile Figure 8. Maximum Concentration of Toluene by Locations with 6 25 feet Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001 Table 18 displays the maximum concentra tion for ethylbenzene in the indoor air as compared to soil vapor at each location with no vadose zone. Soil vapor samples were not collected at seven of the locations due to groundwater in cont act with the building slab. Only one of the locations had higher concentrations of ethyl benzene in the indoor air than in the soil vapor. As seen in Fi gure 9 two locations, 15 and 9 had ethylbenzene

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49 concentrations above the EPA 95th percentil e for background indoor air but were below DOH background concentrations. Table 18. Maximum Concentration of Ethylben zene by Location with No Vadose Zone Maximum Concentrations of Ethylbenzene by Location for Indoor Air vs Soil Vapor (No Vadose Zone) (ug/m3) Location Indoor Air Soil Vapor Location 3 1.31.1 Location 2 0.871.4 Location 14 0.871.4 Location 6 0.871.7 Location 7 0.871.7 Location 10 0.511.7 Location 15 5.71.7 Location 17 0.871.7 Location 18 0.71.7 Location 21 0.871.8 Location 20 1.32.1 Location 11 0.6512.52 Location 13 0.5213.25 Location 9 1.69.3 Location 1 1.3 Location 4 1.3 Location 5 0.87 Location 8 0.87 Location 12 0.88 Location 16 0.87 Location 19 0.87

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50 Ethylbenzene No Vadose Zone1.3 5.7 1.3 1.6 1.31.3 1.41.4 1.71.71.71.71.71.7 1.8 2.1 2.5 3.3 9.3 .87 .87 .88 .87 .87 .52 .65 .87 .7 .87 .51 .87 .87 .87 .87 1.1 0 2 4 6 8 10 12 14Loca t ion 3 L ocati o n 2 Loca t ion 14 L oc a t io n 6 L ocation 7 Lo c a t io n 1 0 L ocation 1 5 Location 17 L oc a t io n 1 8 Location 2 1 Loca t ion 20 L ocati o n 1 1 Location 13 Loca t ion 9 L ocati o n 1 Location 4 Lo c a t io n 5 L ocation 8 Loca t io n 12 L ocati o n 1 6 Location 19Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th %ile Figure 9. Maximum Concentrati on of Ethylbenzene by Locati ons with No Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001

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51 Table 19 displays the maximum concentra tion for ethylbenzene in the indoor air as compared to soil vapor at each location wi th 0-6 feet thick vadose zones. A soil vapor sample was not collected for Location 24. Three of the locations had higher concentrations of ethylbenzene in the indoor air than in the soil vapor. As seen in Figure 10 one location, 24, had ethylbenzene at a conc entration above the EPA 95th percentile for background indoor air but was below DOH background concentrations. Table 19. Maximum Concentrations for Ethyl benzene by Location fo r Indoor Air vs Soil Vapor 0-6 Feet Vadose Zone Maximum Concentrations of Ethylbenzene by Location for Indoor Air vs Soil Vapor (0 6 feet) (ug/m3) Location Indoor Air Soil Vapor Location 28 1.30.61 Location 22 1.90.78 Location 30 0.871.2 Location 31 0.991.2 Location 25 0.871.6 Location 26 0.871.7 Location 29 0.871.7 Location 32 1.31.7 Location 23 0.871.8 Location 27 0.871.9 Location 24 5.34

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52 Ethylbenzene 0-6 Feet Vadose Zone1.3 1.9 1.0 1.3 5.3 1.2 1.6 1.71.7 1.8 1.9 .9 .9 .9 .9 .9 .9 1.7 1.2 .78 .61 0 2 4 6 8 10 12 14Loca t i o n 28 Loca t ion 2 2 Loca t ion 3 0 L o cation 31 L o cat i o n 25 Loca t i o n 26 Loca t ion 2 9 Loca t ion 3 2 L o cation 23 L o cat i o n 27 Loca t i o n 24Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th %ile Figure 10. Maximum Concentration of Ethylben zene by Locations with 06 feet Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001 Table 20 displays the maximum concentra tion for ethylbenzene in the indoor air as compared to soil vapor at each location wi th 6-25 feet thick vadose zones. Two out of the 4 locations had higher concen trations of ethylbenzene in th e indoor air than in the soil vapor. As seen in Figure 11 two lo cations, 36 and 33, had ethylbenzene at a concentrations above the EPA 95th percentile for background indoor air but were below DOH background concentrations.

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53 Table 20. Maximum Concentrations for Ethyl benzene by Location fo r Indoor Air vs Soil Vapor 625 Feet Vadose Zone Maximum Concentrations for Ethylbenzene by Location for Indoor Air vs Soil Vapor (6-25 Feet)(ug/m3) Location Indoor Air Soil Vapor Location 34 0.950.35 Location 36 5.61.2 Location 35 0.472.4 Location 33 3.98.9 Ethylbenzene 6-25 Feet Vadose Zone5.6 3.9 1.2 2.4 8.9 .47 .95 .35 0 5 10 15 20Lo cat ion 3 4 Lo cat ion 3 6 Location 35 Location 33Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th %ile Figure 11. Maximum Concentration of Ethyl benzene by Locations with 6 25 feet Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001

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54 Table 21 displays the maximum concentra tion for m,p-xylene in the indoor air as compared to soil vapor at each location with no vadose zone. Soil vapor samples were not collected at seven of the locat ions due to groundwater in co ntact with the building slab. Five of the locations had higher concentrations of m,p-xylene in the indoor air than in the soil vapor. As seen in Figure 12 one Loca tion 9 had m,p-xylene concentrations in soil vapor above both the EPA and DOH 95th perc entile for background indoor air. Table 21. Maximum Concentratio ns for m,p-Xylene by Locati on for Indoor Air vs Soil Vapor No Vadose Zone Maximum Concentrations of m, pXylene b y Location for Indoor Air vs Soil Vapor (No Vadose Zone) (ug/m3) Location Indoor Air Soil Vapor Location 17 10.44 Location 7 0.960.47 Location 20 3.51.7 Location 14 1.72.2 Location 15 122.9 Location 2 1.63.3 Location 6 0.463.4 Location 10 1.23.4 Location 18 1.73.4 Location 21 23.5 Location 3 6.63.7 Location 11 1.694.16 Location 13 1.175.85 Location 9 4.628 Location 1 3.9 Location 4 3.7 Location 5 0.52 Location 8 0.69

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55 Table 21. (continued) Location 12 2 Location 16 1.7 Location 19 1.7

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56 m,p-Xylene No Vadose Zone1 3.5 12 1.7 2 6.6 4.6 3.9 3.7 2 1.71.7 1.7 2.2 3.3 3.43.43.4 3.5 4.2 5.9 28.0 1.2 1.6 1.7 .96 1.2 .46 1.7 .52 .69 3.7 2.9 .4 .5 0 5 10 15 20 25 30Loc a tion 17 Location 7 Lo c a t i o n 20 Lo c a t i o n 14 Lo c a t i o n 15 Lo cat i on 2 Locati on 6 Loc a t i on 10 Loc a t i on 18 L o c a t i on 21 L ocation 3 Lo c ation 11 Lo c ation 13 Location 9 Location 1 Lo c a t i on 4 Lo c a t i on 5 Lo cat i on 8 Lo c a t i on 12 Loca tion 16 Loc a tion 19Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th%ile Figure 12. Maximum Concentration of m,p-Xy lene by Location with No Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001

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57 Table 22 displays the maximum concentra tion for m,p-xylene in the indoor air as compared to soil vapor at each location with 0-6 feet thick vadose zones. A soil vapor sample was not collected for Location 24. Four of the locations had higher concentrations of m,p-xylene in the indoor air than in the so il vapor. As seen in Figure 13 none of the locations had m,p-xylene con centrations above either the EPA or DOH 95th percentile for background indoor air. Table 22. Maximum Concentratio ns for m,p-Xylene by Locati on for Indoor Air vs Soil Vapor 0-6 Feet Vadose Zone Maximum Concentrations of m, pXylene by Location for Indoor Air vs Soil Vapor (0 -6 feet) (ug/m3) Location Indoor Air Soil Vapor Location 28 2.91.1 Location 32 2.81.5 Location 31 2.41.8 Location 22 6.42.7 Location 25 2.33.3 Location 30 1.43.3 Location 26 1.23.4 Location 29 1.73.4 Location 23 1.63.6 Location 27 2.53.8 Location 24 13.4

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58 Toluene 0-6 Feet Vadose Zone2.6 9.8 2.72.6 5.7 9.2 12 7.7 8.3 10.7 1.21.3 1.91.9 3.3 4.6 5.2 6 6.3 7.4 .86 0 20 40 60 80 100 120L o cation 23 L o cation 29 Location 27 Loca t ion 2 6 Loca t ion 3 2 L oca t ion 2 5 L oc ati on 2 2 L oc ati on 3 1 L oc ati on 3 0 L o cati o n 28 L o cati o n 24Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th %ile Figure 13. Maximum Concentration of m,p-Xy lene by Location with 0-6 feet Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001 Table 23 displays the maximum concentra tion for m,p-xylene in the indoor air as compared to soil vapor at each location with 6-25 feet thick vadose zones. Three out of the 4 locations had higher concen trations of m,p-xylene in th e indoor air than in the soil vapor. As seen in Figure 14, Location 36 exceeded the EPA 95th percentile m,p-xylene in background indoor air.

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59 Table 23. Maximum Concentratio ns for m,p-Xylene by Locati on for Indoor Air vs Soil Vapor 6-25 Feet Vadose Zone Maximum Concentrations of m, pXylene by Location for Indoor Air vs Soil Vapor (6 25 feet) (ug/m3) Location Indoor Air Soil Vapor Location 34 2.20.88 Location 36 201.9 Location 33 134.8 Location 35 1.36.6 m,p-Xylene 6-25 Feet Vadose Zone2.2 20 13 1.3 1.9 4.8 6.6 .88 0 5 10 15 20 25Lo cat ion 3 4 Lo cat ion 3 6 Location 33 Location 35Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th %ile Figure 14. Maximum Concentration of m,p-Xyle ne by Locations with 6 25 feet Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001 Table 24 displays the maximum concentra tion for o-xylene in the indoor air as compared to soil vapor at each location with no vadose zone. Soil vapor samples were not collected at seven of the locat ions due to groundwater in co ntact with the building slab. Five of the locations had higher concentrations of o-xylene in the i ndoor air than in the

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60 soil vapor. As seen in Figure 15 one Locati on 9 had o-xylene concentrations above both the EPA and DOH 95th percentile fo r background indoor air. Table 24. Maximum Concentrations for o-Xy lene by Location for Indoor Air vs Soil Vapor No Vadose Zone Maximum Concentrations of oXylene by Location for Indoor Air vs Soil Vapor (No Vadose Zone)(ug/m3) Location Indoor Air Soil Vapor Location 20 1.41.3 Location 3 3.61.4 Location 14 0.871.4 Location 15 4.41.5 Location 2 0.871.6 Location 6 0.871.7 Location 7 0.871.7 Location 10 0.931.7 Location 17 11.7 Location 18 0.871.7 Location 21 0.871.8 Location 11 0.6071.82 Location 13 0.5212.14 Location 9 1.59.7 Location 1 1.7 Location 4 1.5 Location 5 0.87 Location 8 0.35 Location 12 0.82 Location 16 0.87 Location 19 0.87

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61 o-Xylene No Vadose Zone1.4 3.6 4.4 1.0 1.5 1.7 1.5 1.41.4 1.5 1.6 1.71.71.71.71.7 1.8 1.8 2.1 9.7 .9 .9 .8 .4 .9 .5 .6 .9 .9 .9 .9 .9 .9 .9 1.3 0 2 4 6 8 10 12 14Loca ti on 20 Locatio n 3 Locati o n 14 Loca ti on 15 Locatio n 2 Locati o n 6 Loc atio n 7 L o c ati on 1 0 Locati o n 17 Loca ti on 18 L o c ati on 2 1 Locati o n 11 Loca ti on 13 Location 9 Loca t i o n 1 Loc atio n 4 Locatio n 5 Loca t i o n 8 Loca ti on 12 L o c ati on 1 6 Locati o n 19Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th %ile Figure 15. Maximum Concentration of o-Xy lene by Location with No Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001

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62 Table 25 displays the maximum concentra tion for o-xylene in the indoor air as compared to soil vapor at each location with 0-6 feet thick vadose zones. A soil vapor sample was not collected for Location 24. Two of the locations had higher concentrations of o-xylene in the indoor air than in the so il vapor. As seen in Figure 16 one no locations exceeded the EPA or DOH 95th percentile for background indoor air for o-xylene. Table 25. Maximum Concentrations for o-Xy lene by Location for Indoor Air vs Soil Vapor 0-6 Feet Vadose Zone Maximum Concentrations of oXylene by Location for Indoor Air vs Soil Vapor (0 -6 feet) (ug/m3) Location Indoor Air Soil Vapor Location 22 20.97 Location 31 0.821 Location 25 0.661.6 Location 26 0.871.7 Location 29 0.871.7 Location 30 0.871.7 Location 32 1.11.7 Location 23 0.721.8 Location 27 21.9 Location 28 1.22 Location 24 7.46

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63 o-Xylene 0-6 Feet Vadose Zone2.0 1.1 2.0 1.2 7.5 1 1.6 1.71.71.71.7 1.8 2 .7 .9 .9 .9 .7 .8 1.9 .97 0 2 4 6 8 10 12 14L o c a ti o n 2 2 L o c a ti o n 3 1 L o c a t i o n 2 5 L o c a t i o n 2 6 L o c a t i o n 2 9 L o c a t i o n 3 0 L o c a t i o n 3 2 L o c a ti o n 2 3 L o c a ti o n 2 7 L o c a ti on 2 8 L o c a ti o n 2 4Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th%ile Figure 16. Maximum Concentration of o-Xylene by Location with 0-6 feet Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001 Table 26 displays the maximum concentra tion for o-xylene in the indoor air as compared to soil vapor at each location with 6 25 feet thick vadose zones. Two out of the 4 locations had higher con centrations of o-xylene in th e indoor air than in the soil vapor. As seen in Figure 17, Locations 36a nd 33 had o-xylene concentrations above the EPA 95th percentile for background indoor air. Table 26. Maximum Concentrations for o-Xylene by Location for Indoor Air vs Soil Vapor 6-25 Feet Vadose Zone Maximum Concentrations of oXylene by Location for Indoor Air vs Soil Vapor (6 -25 feet)(ug/m3) Location Indoor Air Soil Vapor Location 34 0.740.41

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64 Table 26.(continued) Location 36 6.41.2 Location 35 0.513.5 Location 33 2.98.9 o-Xylene 6-25 Feet Vadose Zone6.4 2.9 1.2 3.5 8.9 .51 .74 .41 0 5 10 15 20 25 30Lo cat ion 3 4 Lo cat ion 3 6 Location 35 Location 33Concentration (ug/m3) Indoor Air Soil Vapor DOH 95th %ile EPA 95th %ile Figure 17. Maximum Concentration of o-Xylene by Locations with 6 25 feet Vadose Zone DOH 95th% ile – NYSDOH Background 95th Percentile for Indoor Air, 2003 EPA 95th %ileUSEPA BASE Background 95th Percentile for Indoor Air, 2001 Based on the results of the assessment c onducted for the 36 properties included in this study, no evidence of soil vapor intrus ion was found regardless of the thickness of vadose zone. Even at locations where i ndoor air concentrations exceeded background these concentrations were an order of magn itude below reference concentrations. The highest concentration of ben zene in indoor air was detected at Location 24 at 4.72 ug/m3. The RfC for benzene is 3x10-2 mg/m3. The highest concentration for toluene in indoor air was detected at Location 9 at 220 ug/m3. The RfC for toluene is 5 mg/m3.

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65 The highest concentration for ethylbenzene in indoor air was de tected at Location 15 at 5.7 ug/m3. The RfC for ethylbenzene is 1mg/m3. The highest concentration for m,p-xylene in indoor air was de tected at Location 15 at 12ug/m3. The RfC for xylenes is 0.1 mg/m3. The highest concentration for o-xylene in indoor air was de tected at Location 24 at 7.46 ug/m3. The RfC for xylenes is 0.1 mg/m3. The following figures (18-26) depict di fference in frequency of detections between outdoor air, indoor ai r, and soil vapor categorized by vadose zones. Figure 18 depicts the difference in the frequency of det ection for chemicals detected in the outdoor air versus the indoor air of bu ildings with no vadose zones. The positive values represent more detections for benzene, carbon disulfide, toluene, and m,p-xylene in the outdoor air than in the indoor air. Carbon disulfide is a natural product of anaer obic biodegradation; benzene, toluene, and m,p-xylene are all petroleum-related chemicals. The presence of these chemicals in the outdoor air co uld account for some proportion of their concentrations found in indoor air. Figure 19 depicts the difference in the frequency of detection for chemicals detected in the outdoor air vers us the indoor air of buildings with 0-6 feet thick vadose zones. The positive values represent more detections for benzene, thiophene, toluene, 1,2,3-trimethylbenzene, and m,p-xylene in the out door air than in the in door air. All of these chemicals are petroleum-related. The pr esence of these chemicals in the outdoor air could account for some proportion of their c oncentrations found in indoor air. Figure 20 depicts the difference in the frequency of detection for chemicals detected in the outdoor air vers us the indoor air of buildings with 6-25 feet thick vadose zones. The positive values represent more detections for benzene, n-decane,

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66 2-methylnaphthalene, toluene, 1,2,3-trim ethylbenzene 1,2,4-trimethylbenzene, nundecane, m,p-xylene, and o-xylene in the outdoor air than in the indoor air. All of these chemicals are present in petroleum-related compounds. The presence of these chemicals in the outdoor air could account for some proportion of their con centrations found in indoor air. Figure 21 depicts the difference in the frequency of detection for chemicals detected in the indoor air ve rsus soil vapor of buildings with no vadose zones. The positive values represent more detections for benzene, ethylbenzene, indan, 1-methylnaphthalene, nonane, toluene, 1,2,4trimethylbenzene, 1,3,5trimethylbenzene, m,p-xylene and o-xylene in the i ndoor air than in so il vapor. All of these chemicals are petroleum-related. Figure 22 depicts the difference in the frequency of detection for chemicals detected in the indoor air versus soil vapor of buildings with 0-6 feet thick vadose zones. The positive values represent more detect ions for n-decane, ethylbenzene, indan, 1-methylnaphthalene, 2-methylnaphthalene 2-methylthiophene, 3-methylthiophene, nonane, 1,2,4,5-tetramethylbenzene, 1,2,4-trimet hylbenzene, 1,3,5-trimethylbenzene, nundecane, m,p-xylene and o-xylene in the indoor air than in soil vapor. All of these chemicals are petroleum-related. Figure 23 depicts the difference in the frequency of detection for chemicals detected in the indoor air versus soil vapor of buildings with 6-25 feet thick vadose zones. The positive values represent more detecti ons for benzene, benzothiophene, n-decane, ndodecane, ethylbenzene, nonane, thiophene, toluene, 1,2,3-trimethylbenzene,

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67 1,2,4-trimethylbenzene, n-undecane, m,p-xylene a nd o-xylene in the indoor air than in soil vapor. All of these ch emicals are petroleum-related. Figure 24 depicts the difference in the frequency of detection for chemicals detected in the outdoor air versus soil vapor of buildings with no vadose zones. The positive values represent more detections for benzene, ethylbenzene, toluene, m,p-xylene and o-xylene in the outdoor air than in soil vapor. All of these chemicals are petroleumrelated. Figure 25 depicts the difference in the frequency of detection for chemicals detected in the outdoor air versus soil vapor of buildings with 0-6 feet thick vadose zones. The positive values represent more detections for benzene, n-dodecane, ethylbenzene, thiophene, toluene, 1,2,3-trimethylbe nzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, m,p-xylene and o-xylene in the outdoor air th an in soil vapor. All of these chemicals are petroleum-related. Figure 26 depicts the difference in the frequency of detection for chemicals detected in the outdoor air versus soil vapor of buildings with 6-25 feet thick vadose zones. The positive values represent more detections for benzene, n-decane, 2-methylnaphthalene, toluene, 1,2,3-trim ethylbenzene, 1,2,4-trimethylbenzene, n-undecane, m,p-xylene and o-xylene in the outd oor air than in soil vapor. All of these chemicals are petroleum-related. Based on the analyses of this data the five chemicals with highest frequency of detection in the study results, benzene, toluene, ethylbenzen e, m,p-xylene, and o-xylene, were more frequent in outdoor air than in indoor ai r and soil vapor.

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68 -10% -5% 0% 5% 10% 15% 20%B enze ne Benz o thiophe n e Ca r b on d i sul f ide D e cane n D ode ca ne, n Et h ylb e nzene E thy l thi op hene, 2 I nda n Inden e M ethylnaphthalene,1M et h yl nap ht h al en e, 2Methylthiophene, 2Methyl t hi o phe ne 3Naphthalene No na ne St y re n e Tetr amet h yl ben zen e, 1 ,2 4,5Th io p hene Tol u ene Trim eth yl ben ze ne,1, 2, 3T r i met h ylb en zene,1,2, 4Trim e th y lben z ene,1, 3 ,5Un de cane, n Xylene m ,pXyl e ne, o-Difference in frequency of detections No vadose OAIR IAIR Figure 18. Difference in Frequency of Detections between Outdoor Air an d Indoor Air with No Vadose Zone. A positive value represents more detections found in outdoor air. OAIR – Outdoor Air IAIR – Indoor Air

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69 -0.1 -0.05 0 0.05 0.1 0.15 0.2Benzene B enzo t hi o phe ne Carbon disu l fide D e cane, nDo d ecane, nE t h ylb en zene E t h ylthi op hene 2 I nd an Inden e M e t hyl na pht h al e ne, 1 Me t hylnaphthalene,2M e t hyl t h i oph ene 2Methylthiophene, 3Naphthalene N o nane Styr e ne Tetr a m ethyl ben ze ne,1, 2, 4 5Thiophe ne T ol u ene T rimet h ylbe n zene,1,2,3Tr i methyl benzen e, 1,2, 4 T rimet h ylbenzene,1,3,5U nd ecan e, nXylene, m,pX yl en e, o-Difference in frequency of detections 0-6 feet OAIR IAIR Figure 19. Difference in Frequency of De tections between Outdoor Air and Indoor Air with a 0-6 Foot Vadose Zone. A positive value represents more detections found in outdoor air. OAIR – Outdoor Air IAIR – Indoor Air

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70 -0.1 -0.05 0 0.05 0.1 0.15 0.2Benz e ne B enzo t hi op he ne Carbon disulfide D eca ne, nD od ecan e, n Ethylbenzene E t hyl thi oph ene 2 I nd an Indene M ethyl n aphthal e ne,1Me t hylnaph t ha l ene 2Methylthiophene, 2M e t hyl thi op hene 3 Naphthalene Nonane S t yr e ne T et ramet h ylb en zene,1,2, 4, 5T hi op hene T ol ue ne Tr i methylb e nzene,1,2, 3 T rimet hy lbe nz ene,1,2 ,4 T rimet hy lbe nz ene,1, 3 ,5 Un d ecane, n X yl en e, m, pXylene, o -Difference in frequency of detections 6-25 feet OAIR IAIR Figure 20. Difference in Frequency of De tections between Outdoor Air and Indoor Air with a 6-25 Foot Vadose Zone. A positive value represents more detections found in outdoor air. OAIR – Outdoor Air IAIR – Indoor Air

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71 -0.1 -0.05 0 0.05 0.1 0.15 0.2B enze ne Benzothiophene C arbon di su lfi de Decane, nD od ecan e, n Ethylbenzene E t hyl t h i ophe ne 2Indan I nd en e Methylnaphthalene,1M e t hyl n aph t ha le ne 2Me t hylt h iop h ene, 2 M ethyl t h i oph en e, 3Na p hth a len e N on ane Styren e T et r amethyl b enzen e ,1 2,4, 5 T h iophene T ol ue ne T r i methy l ben zen e, 1, 2 3Trimethyl b enzen e ,1,2,4T r i met hy l ben zen e, 1, 3 5U n decan e, nXylene, m ,pX yl en e, o-Difference in frequency of detection s No vadose IAIR SV Figure 21. Difference in Frequency of Detections between Indoor Air a nd Soil Vapor with No Vadose Zone. A positive value represents more detections found in indoor air IAIR – Indoor Air SV – Soil Vapor

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72 -0.1 -0.05 0 0.05 0.1 0.15 0.2Benzene B enzo t hi o phe ne Carbon disu l fide D e cane, nDo d ecane, nE t h ylb en zene E t h ylthi op hene 2 I nd an Inden e M e t hyl na pht h al e ne, 1 Me t hylnaphthalene,2M e t hyl t h i oph ene 2Methylthiophene, 3Naphthalene N o nane Styr e ne Tetr a m ethyl ben ze ne,1, 2, 4 5Thiophe ne T ol u ene T rimet h ylbe n zene,1,2,3Tr i methyl benzen e, 1,2, 4 T rimet h ylbenzene,1,3,5U nd ecan e, nXylene, m,pX yl en e, o-Difference in frequency of detection s 0-6 feet IAIR SV Figure 22. Difference in Frequency of De tections between Indoor Air and Soil Vapor with a 0-6 Foot Vadose Zone. A positive value represents more detections found in indoor air IAIR – Indoor Air SV – Soil Vapor

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73 -0.1 -0.05 0 0.05 0.1 0.15 0.2Benz e ne B enzo t hi op he ne Carbon disulfide D eca ne, nD od ecan e, n Ethylbenzene E t hyl thi oph ene 2 I nd an Indene M ethyl n aphthal e ne,1Me t hylnaph t ha l ene 2Methylthiophene, 2M e t hyl thi op hene 3 Naphthalene Nonane S t yr e ne T et ramet h ylb en zene,1,2, 4, 5T hi op hene T ol ue ne Tr i methylb e nzene,1,2, 3 T rimet hy lbe nz ene,1,2 ,4 T rimet hy lbe nz ene,1, 3 ,5 Un d ecane, n X yl en e, m, pXylene, o -Difference in frequency of detection s 6-25 feet IAIR SV Figure 23. Difference in Frequency of De tections between Indoor Air and Soil Vapor with a 6-25 foot Vadose Zone. A positive value represents more detections found in indoor air. IAIR – Indoor Air SV – Soil Vapor

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74 -0.1 -005 0 0.05 0.1 0.15 0.2B enze n e Benzothi o phene C a r bo n d isu l f i de D e cane, n Dodec an e, nE t h ylb en zene E t h ylthi op hene 2 Inda n I nd ene M e t hyl n aph t ha le ne 1Methylnaphthalene,2M e thylthiophene, 2 Met hyl thi op hen e, 3Napht h alene Nonane S t y r en e Tetr a me t hy l benz e ne, 1 ,2 4,5Thiophene T ol ue ne T r i m e t hy l b enz ene 1, 2,3Trim e thy l ben z ene,1,2 4T r i m e t hyl b enz ene 1, 3,5U n dec ane nXylene, m ,pX yl en e, o-Difference in frequency of detections No vadose OAIR SV Figure 24 Difference in Frequency of Detections between Outdoor Air and Soil Vapor with No Vadose Zone. A positive value represents more detections found in outdoor air OAIR Outdoor Air SV Soil Vapor

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75 -0.1 -0.05 0 0.05 0.1 0.15 0.2B enz ene Benzothiophene C arbon di su lfi de De c ane, nD o decan e, nEth yl ben ze ne Eth yl thiop h ene, 2Indan I nd ene Methyln a pht h alene, 1 M ethyl n aphthal e ne,2Me t hylthiophene, 2M e t hyl t h i oph ene 3N ap ht ha l ene No n ane S t yrene Tetra m ethylbenze n e,1,2,4,5Th i op he ne T o luene T r im et h yl ben ze ne, 1 2, 3Tri methyl b enze ne ,1 2,4T r im et h yl ben ze ne, 1 3, 5Undecane, nX yl en e, m, pXylene, o-Difference in frequency of detections 0-6 feet OAIR SV Figure 25. Difference in Frequency of De tections between Outdoor Air and Soil Vapor with a 0-6 foot Vadose Zone. A positive value represents more detections found in outdoor air OAIR – Outdoor Air SV – Soil Vapor

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76 -0.1 -0.05 0 0.05 0.1 0.15 0.2Benz e ne B enzo t hi op he ne Carbon disulfide D eca ne, nD od ecan e, n Ethylbenzene E t hyl thi oph ene 2 I nd an Indene M ethyl n aphthal e ne,1Me t hylnaph t ha l ene 2Methylthiophene, 2M e t hyl thi op hene 3 Naphthalene Nonane S t yr e ne T et ramet h ylb en zene,1,2, 4, 5T hi op hene T ol ue ne Tr i methylb e nzene,1,2, 3 T rimet hy lbe nz ene,1,2 ,4 T rimet hy lbe nz ene,1, 3 ,5 Un d ecane, n X yl en e, m, pXylene, o -Difference in frequency of detections 6-25 feet OAIR SV Figure 26 Difference in Frequency of Detec tions between Outdoor Air and Soil Va por with a 6-25 foot Vadose Zone. A positive value represents more detections found in outdoor air OAIR – Outdoor Air SV – Soil Vapor

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77 Comparative risk analyses were conducted for mean and maximum concentrations detected in indoor and outdoor air and soil vapor to determine potential carcinogenic and non-carcinogeni c health risks. Table 27 summarizes the minimum, mean, and maximum concentrations found in the study results for outdoor air categorized by vadose zone. Table 27. Minimum, Maximum and Mean Conc entrations of Detected Chemicals in Outdoor Air by Thickness of Vadose Zone (ug/m3) Outdoor Air No vadose zone 0-6 feet 6-25 feet Chemical Min Max Mean Min Max Mean Min Max Mean Benzene 0.22 2.65 0.79 0.66 2.5 1.14 0.54 1.2 0.79 Carbon disulfide 0.19 0.38 0.30 0.35 0.35 0.35 Decane, n0.62 0.62 0.62 0.41 1.7 0.97 0.29 0.87 0.62 Dodecane, n0.35 0.96 0.59 0.96 2.4 1.82 0.42 0.63 0.53 Ethylbenzene 0.24 0.83 0.44 0.26 1.3 0.76 1.1 1.4 1.25 Indan 0.4 0.4 0.40 2-Methylphthalene 0.34 0.34 0.34 0.35 0.35 0.35 Naphthalene 0.35 0.35 0.35 0.26 0.26 0.26 Nonane 0.52 0.52 0.52 0.42 0.47 0.44 0.63 0.73 0.68 Styrene 0.84 0.84 0.84 Thiophene 0.4 0.4 0.40 Toluene 0.26 6.4 1.74 0.76 8.5 3.49 1 9.9 4.23 1,2,3Trimethylbenzene 0.34 2.6 1.09 0.29 0.34 0.32 1,2,4Trimethylbenzene 0.65 2.6 1.24 0.25 0.74 0.54 1,3,5Trimethylbenzene 0.29 0.93 0.61 Undecane, n0.38 2.6 1.46 0.45 2.5 1.25 0.32 0.89 0.66 Xylene, m,p0.33 2.5 0.81 0.44 2.7 1.31 0.59 4.1 2.23 Xylene, o0.23 0.39 0.31 0.26 1.1 0.73 0.22 1.1 0.61

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78 Table 28 summarizes the minimum, mean, and maximum concentrations found in the study results for indoor ai r categorized by vadose zone. Table 28. Minimum and Maximum Concentrations of Detected Chemicals in Indoor Air by Thickness of Vadose Zone (ug/m3) Indoor Air No vadose zone 0-6 feet 6-25 feet Chemical Min Max Mean Min Max Mean Min Max Mean Benzene 0.31 4.4 0.88 0.58 4.72 1.36 0.7 2.8 1.29 Benzothiophene 0.346 0.346 0.35 0.274 0.274 0.27 Carbon disulfide 0.23 3.1 0.81 0.63 42.9 7.23 0.44 0.44 0.44 Decane, n0.29 50 3.93 0.52 8. 32 1.81 0.63 2.7 1.22 Dodecane, n0.35 36 4.25 0.42 16 3.04 0.56 2.1 1.21 Ethylbenzene 0.24 5.7 0.91 0.44 5.34 1.12 0.27 5.6 1.33 Indan 0.3 1.4 0.69 0.28 0.961 0.61 0.111 1.1 0.47 Indene 0.237 0.42 0.33 0.119 0.119 0.12 1-Methylphthalene 0.46 4.4 1.72 0.29 1.9 0.66 0.29 1.15 0.60 2-Methylphthalene 0.453 5.6 2.64 0.41 8.7 1.64 0.29 2.24 0.71 2-Methylthiophene 0.26 0.26 0.26 3-Methylthiophene 0.26 0.26 0.26 Naphthalene 0.29 2.5 1.03 0.4 12.9 2.58 0.26 0.84 0.41 Nonane 0.27 4 1.50 0.38 4.5 1.39 0.28 2.6 0.92 Styrene 0.25 19 3.62 0.3 6.09 1.16 0.132 0.98 0.45 1,2,4,5Tetramethylbenzene 0.44 4.8 1.18 0.33 15 5.55 0.055 1.3 0.48 Thiophene 0.41 0.41 0.41 Toluene 0.82 220 16.46 0.91 12 5.62 2.6 31 7.05 1,2,3Trimethylbenzene 0.295 20 4.57 0.39 5.26 2.09 0.28 1.8 0.49 1,2,4Trimethylbenzene 0.26 20 3.51 0.77 11.3 1.95 0.39 5 0.98 1,3,5Trimethylbenzene 0.44 6.6 2.12 0.45 8.55 1.47 0.226 1.2 0.45 Undecane, n0.35 140 8.22 0.38 12 2.57 0.51 7.7 1.62 Xylene, m,p0.27 12 1.92 0.43 13.4 2.47 0.67 20 4.20 Xylene, o0.217 4.4 0.98 0.43 7.46 1.19 0.3 6.4 1.22

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79 Table 29 summarizes the minimum, mea n, and maximum concentrations found in the study results for soil vapor categorized by vadose zone. Table 29. Minimum and Maximum Concentrations of Detected Chemicals in Soil Vapor by Thickness of Vadose Zone (ug/m3) Soil Vapor No vadose zone 0-6 feet 6-25 feet Chemical Min Max Mean Min Max Mean Min Max Mean Benzene 0.48 58 9.55 0.62 8.2 2.90 0.96 3.2 1.98 Benzothiophene 1.1 1.4 1.25 Carbon disulfide 0.666 12 4.08 1.5 5.1 3.37 6.7 16 10.13 Decane, n0.73 10 3.36 0.94 1.7 1. 36 3.8 18.3 7.47 Dodecane, n1.11 100 15.78 0.93 9.1 3.63 3.8 383 108.40 Ethylbenzene 0.48 9.3 2.43 0.61 1.2 0.95 0.35 2.4 1.32 Indan 1.3 6.6 3.17 0.55 0.55 0.55 0.239 0.79 0.58 Indene 0.53 1.8 0.84 0.89 0.89 0.89 1-Methylphthalene 6 6 6.00 0.73 0.8 0.77 7.5 340 162.50 2-Methylphthalene 0.93 14 6.01 2 2.1 2.05 0.38 512 185.47 Naphthalene 0.55 33 5.93 0.59 0.94 0.79 0.4 11.9 3.22 Nonane 0.897 3.9 1.92 0.82 1.8 1.23 0.58 7.3 2.74 Styrene 0.3 2.6 1.23 0.56 2.1 1.30 0.43 1.6 0.78 1,2,4,5Tetramethylbenzene 0.38 26 9.01 3.1 3.1 3.10 0.55 6.8 2.26 Thiophene 0.81 0.81 0.81 0.72 0.72 0.72 Toluene 0.92 430 29.33 0.77 6.3 2.86 1.8 12.9 7.88 1,2,3Trimethylbenzene 0.44 3.9 1.97 1.3 1.3 1.30 0.73 3 1.53 1,2,4Trimethylbenzene 0.55 3.68 1.89 1.3 1.6 1.43 1.1 5.3 2.50 1,3,5Trimethylbenzene 0.39 2.2 1.15 0.496 3.6 1.50 Undecane, n0.738 29 4.32 1.2 3.9 2.10 3.2 77.2 19.54 Xylene, m,p0.44 28 4.48 1.1 3.3 1.93 0.62 6.6 3.64 Xylene, o0.61 9.7 2.29 0.97 1.7 1.22 0.41 3.5 1.87 Tables 30 through 33 summarize the minimum, maximum and mean concentrations for benzene, toluene, et hylbenzene, m,p-xylene, and o-xylene, the chemicals with the highest frequency of det ection from the study results in indoor and outdoor air, and soil vapor.

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80 Table 30. Summary Table of Minimum, Maximu m and Mean Concentrations of Highest Frequency Chemicals in Outdoor Air by Thickness of Vadose Zone (ug/m3) Outdoor Air No vadose zone 0-6 feet 6-25 feet Chemical Min Max Mean Min Max Mean Min Max Mean Benzene 0.22 2.65 0.79 0.66 2.5 1.14 0.54 1.2 0.79 Ethylbenzene 0.24 0.83 0.44 0.26 1.3 0.76 1.1 1.4 1.25 Toluene 0.26 6.4 1.74 0.76 8.5 3.49 1 9.9 4.23 Xylene, m,p0.33 2.5 0.81 0.44 2.7 1.31 0.59 4.1 2.23 Xylene, o0.23 0.39 0.31 0.26 1.1 0.73 0.22 1.1 0.61 Table 31. Summary Table of Minimum, Maximu m and Mean Concentrations of Highest Frequency Chemicals in Indoor Air by Thickness of Vadose Zone (ug/m3) Indoor Air No vadose zone 0-6 feet 6-25 feet Chemical Min Max Mean Min Max Mean Min Max Mean Benzene 0.31 4.4 0.88 0.58 4.72 1.36 0.7 2.8 1.29 Ethylbenzene 0.24 5.7 0.91 0.44 5.34 1.12 0.27 5.6 1.33 Toluene 0.82 220 16.46 0.91 12 5.62 2.6 31 7.05 Xylene, m,p0.27 12 1.92 0.43 13.4 2.47 0.67 20 4.20 Xylene, o0.217 4.4 0.98 0.43 7.46 1.19 0.3 6.4 1.22 Table 32. Summary Table of Minimum, Maximu m and Mean Concentrations of Highest Frequency Chemicals in Soil Vapor by Thickness of Vadose Zone (ug/m3) Soil Vapor No vadose zone 0-6 feet 6-25 feet Chemical Min Max Mean Min Max Mean Min Max Mean Benzene 0.48 58 9.55 0.62 8.2 2.90 0.96 3.2 1.98 Ethylbenzene 0.48 9.3 2.43 0.61 1.2 0.95 0.35 2.4 1.32 Toluene 0.92 430 29.33 0.77 6.3 2.86 1.8 12.9 7.88 Xylene, m,p0.44 28 4.48 1.1 3.3 1.93 0.62 6.6 3.64 Xylene, o0.61 9.7 2.29 0.97 1.7 1.22 0.41 3.5 1.87 To determine the potential risk of non-carcinogenic health effects the concentrations summarized in Tables 30 th rough 32 were used to calculate hazard quotients (HQ) for each chemical by media and vadose zones. The HQs were used to obtain Hazard Indices (HIs) to assess the overall potential for non-carcinogenic effects posed by chemicals by vadose zone. To calculate HQs the concentrations from the study

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81 results were divided by the i ndividual chemicals’ RfCs. These HQs were then summed to obtain the HIs. HIs of 1 or less are considered to not pose chronic non-carcinogenic health hazards to the public. Table 33 summarizes the HQs and HIs for the mean concentrations of the study results for indoor air. HIs for the chemical s in the no vadose zone, the 0-6 feet thick vadose zone, and the 6-25 feet thick vadose zone were all below 1. Table 33. Hazard Indices for Mean Concen trations for Indoor Air by Vadose Zone Hazard Index (HI) for Mean Concentrations for Indoor Air Chemical No Vadose 0-6 Ft Vadose 6-25 Ft Vadose Benzene 0.0291670.0452043010.0429125 Ethylbenzene 0.00091460.0011164290.001332063 Toluene 0.0032910.0011247890.00141025 Xylene, m,p0.0191530.02470.042 Xylene, o0.0981730.011861290.0122275 Hazard Index 0.050.070.09 Table 34 summarizes the HQs and HIs for the maximum concentrations of the study results for indoor air. HIs for the ch emicals in the no vadose zone, the 0-6 feet thick vadose zone, and the 6-25 feet thick vadose zone were all below 1. Table 34. Hazard Indices for Maximum Concen trations for Indoor Air by Vadose Zone Hazard Index (HI) for Maximum Concentrations for Indoor Air Chemical No Vadose 0-6 Ft Vadose 6-25 Ft Vadose Benzene 0.1466670.15733330.093333 Ethylbenzene 0.00570.005340.0056

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82 Table 34. (continued) Toluene 0.0440.00240.0062 Xylene, m,p0.120.1340.2 Xylene, o0.0440.07460.064 Hazard Index 0.320.300.31 Table 35 summarizes the HQs and HIs for the mean concentrations of the study results for soil vapor. HIs for the chemical s in the no vadose zone, the 0-6 feet thick vadose zone, and the 6-25 feet thick vadose zone were all below 1. Table 35. Hazard Indices for Mean Concen trations for Soil Vapor by Vadose Zone Hazard Quotient (HQ) for Mean Concentrations for Soil Vapor Chemical No Vadose 0-6 Ft Vadose 6-25 Ft Vadose Benzene 0.3180.096550.06613 Ethylbenzene 0.00240.000950.00132 Toluene 0.005870.000570.00158 Xylene, m,p0.04470.019330.03638 Xylene, o0.022910.012230.01873 Hazard Index 0.370.120.11 Table 36 summarizes the HQs and HIs for the maximum concentrations of the study results for soil vapor. HIs for the chemi cals in the 0-6 feet thick vadose zone, and the 6-25 feet thick vadose zone were below 1, however the HI for the no vadose zone was above 1.

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83 Table 36. Hazard Indices for Maximum Concen trations for Soil Vapor by Vadose Zone Hazard Quotient (HQ) for Maximum Concentrations for Soil Vapor Chemical No Vadose 0-6 Ft Vadose 6-25 Ft Vadose Benzene 1.930.3183333330.1067 Ethylbenzene 0.010.00120.0024 Toluene 0.090.000240.0005 Xylene, m,p0.280.0330.0660 Xylene, o0.100.0170.0350 Hazard Index 2.310.350.18 Table 37 summarizes the HQs and HIs for the mean concentrations of the study results for outdoor air. HIs for the chemi cals in the no vadose zone, the 0-6 feet thick vadose zone, and the 6-25 feet thick vadose zone were all below 1. Table 37. Hazard Indices for Mean Concentr ations for Outdoor Air by Vadose Zone Hazard Quotients (HQ) for Mean Concentrations for Outdoor Air Chemical No Vadose 0-6 Ft Vadose 6-25 Ft Vadose Benzene 0.026380950.0379259260.04 Ethylbenzene 0.000440630.000760.00125 Toluene 0.000348670.0006989090.000845 Xylene, m,p0.008056110.0131122220.02225 Xylene, o0.003140.007280.006125 Hazard Index 0.040.060.07 Table 38 summarizes the HQs and HIs for the maximum concentrations of the study results for outdoor air. HIs for the ch emicals in the no vadose zone, the 0-6 feet thick vadose zone, and the 6-25 feet thick vadose zone were all below 1.

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84 Table 38. Hazard Indices for Maximum Concentr ations for Outdoor Air by Vadose Zone Hazard Quotients (HQ) for Maxi mum Concentrations for Outdoor Air Chemical No Vadose 0-6 Ft Vadose 6-25 Ft Vadose Benzene 0.088333330.0833333330.04 Ethylbenzene 0.000830.00130.0014 Toluene 0.001280.00170.00198 Xylene, m,p0.0250.0270.041 Xylene, o0.00390.0110.011 Hazard Index 0.120.120.10 For comparative purposes HQs and HIs were calculated for the mean, maximum and 95th percentile concentrations from both the EPA and the NYSDOH background studies. Table 39 summarizes the HQs and HIs for the maximum, mean and 95th percentile concentrations from the DOH bac kground study for indoor air. The HIs for the mean and 95th percentile concentrations were be low 1, however the HI for the maximum concentrations was 24.37533333, well above 1. As with the study results for soil vapor with no vadose zone, the driver for th is risk calculation was benzene. Table 39. Hazard Indices for DOH B ackground Maximum, Mean and 95th Percentile Concentrations for Indoor Air Hazard Quotient (HQ) for DOH Back ground Concentrations for Indoor Air Chemical Maximum Mean 95th Percentile Benzene 15.333333330.2766666670.966666667 Ethylbenzene 0.340.00370.013 Toluene 0.1020.00520.022 Xylene, m,p5.50.0590.21 Xylene, o3.10.0380.13 Hazard Index 24.380.381.34

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85 Table 40 summarizes the HQs and HIs for the maximum, mean and 95th percentile concentrations from the DOH b ackground study for outdoor air. HIs for these concentrations were all below 1. Table 40. Hazard Indices for DOH B ackground Maximum, Mean and 95th Percentile Concentrations for Outdoor Air Hazard Quotient (HQ) for DOH Background Concentrations for Outdoor Air Chemical Maximum Mean 95th Percentile Benzene 0.1466670.0633333330.093333 Ethylbenzene 0.00570.00080.0056 Toluene 0.0440.00220.0062 Xylene, m,p0.120.0080.2 Xylene, o0.0440.0070.064 Hazard Index 0.320.080.31 Table 41 summarizes the HQs and HIs for the maximum, mean and 95th percentile concentrations from the EPA b ackground study for indoor air. The HIs for the mean and 95th percentile concentrations were be low 1, however the HI for the maximum concentrations was 5.76466, well above 1. As with the HI for the maximum concentration in the DOH study, the driver fo r this risk calculation was benzene. Table 41. Hazard Indices for EPA Background Maximum, Mean and 95th Percentile Concentrations for Indoor Air Hazard Quotient (HQ) for EPA Back ground Concentrations for Indoor Air Chemical Maximum Mean 95th Percentile Benzene 2.10.150.416666667 Ethylbenzene 0.07360.00280.0076 Toluene 0.078060.005020.01416

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86 Table 41. (continued) Xylene, m,p2.6080.1080.285 Xylene, o0.9050.0380.112 Hazard Index 5.760.300.84 Table 42 summarizes the HQs and HIs for the maximum, mean and 95th percentile concentrations from the EPA background study for outdoor air. HIs for these concentrations were all below 1. Table 42. Hazard Indices for EPA Background Maximum, Mean and 95th Percentile Concentrations for Outdoor Air Hazard Quotient (HQ) for EPA Background Concentrations for Outdoor Air Chemical Maximum Mean 95th Percentile Benzene 0.4333333330.1066666670.32 Ethylbenzene 0.00780.00140.0043 Toluene 0.018620.003080.00984 Xylene, m,p0.2680.0560.161 Xylene, o0.1110.020.06 Hazard Index 0.840.190.56 Figures 27 through 32 compare the calcu lated Hazard Indices from the study results to the EPA and NYSDOH background st udies calculated Hazard Indices. As these figures demonstrate, the HIs from study results are below the HIs calculated from regulatory background concentrations.

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87 Hazard Index Comparison for Outdoor Air Mean Concentrations 0 0.05 0.1 0.15 0.2N o V a d o s e 0 6 F t V a d o s e 6 2 5 F t V a d o s e D O H E P A Hazard Index Figure 27. Hazard Index Comparison for Outdoor Air Mean Concentrations NYSDOH Background Outdoor Air Mean Concentrations, 2003 USEPA Background Outdoor Air Mean Concentrations, 2001

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88 Hazard Index Comparison for Outdoor Air Maximum Concentrations0.00 0.20 0.40 0.60 0.80 1.00N o V a d o s e 0 6 F t V a d o s e 6 2 5 F t V a d o s e D O H E P A Hazard Index Figure 28. Hazard Index Comp arison for Outdoor Air Maximum Concentrations NYSDOH Background Outdoor Air Maximum Concentrations, 2003 USEPA Background Outdoor Air Maximum Concentrations, 2001

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89 Hazard Index Comparisons for Indoor Air Mean Concentrations0 0.1 0.2 0.3 0.4 0.5N o V a d o s e 0 6 F t V a d o s e 6 2 5 F t V a d o s e D O H E P A Hazard Index Figure 29. Hazard Index Comparison for Indoor Air Mean Concentrations NYSDOH Background Indoor Air M ean Concentrations, 2003 USEPA Background Indoor Air Mean Concentrations, 2001

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90 Hazard Index Comparison for Indoor Air Maximum Concentrations0 5 10 15 20 25 30N o V a d o s e 0 6 F t V a d o s e 6 2 5 F t V a d o s e D O H E P A Hazard Index Figure 30. Hazard Index Comparison for Indoor Air Maximum Concentrations NYSDOH Background Indoor Air Ma ximum Concentrations, 2003 USEPA Background Indoor Air Ma ximum Concentrations, 2001

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91 Hazard Index Comparison for Soil Vapor Mean Concentrations0 0.1 0.2 0.3 0.4 0.5No Vad os e 0-6 Ft Vadose 6 -2 5 Ft Vad o s e DOH* EPA* Hazard Index Figure 31. Hazard Index Comparison for Soil Vapor Mean Concentrations *NYSDOH Background Indoor Air M ean Concentrations, 2003 *USEPA Background Indoor Air Mean Concentrations, 2001

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92 Hazard Index Comparison for Soil Vapor Maximum Concentrations0 5 10 15 20 25 30 No Vadose 0-6 Ft Vadose 6-25 Ft Vadose DOH*EPA* Hazard Index Figure 32. Hazard Index Comparison for Soil Vapor Maximum Concentrations *NYSDOH Background Indoor Air Ma ximum Concentrations, 2003 *USEPA Background Indoor Air Maximum Concentrations, 2001

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93 Benzene, a known human carcinogen, was the chemical with the highest frequency of detection in the study results. Inhalation is the only route of exposure that this study considered. Cancer risks from i nhalation of benzene were calculated by multiplying the mean and maximum concentratio ns in indoor air, outdoor air, and soil vapor by the inhalation unit risk (IUR) range of 2.2x10-6 and 7.8x10-6. Based on this IUR, exposure to 1 g/m3 benzene in air results in an in creased lifetime risk or IUR of 2.210 6 to 7.810 6 of developing leukemia. A generally acceptable range for cumulative excess lifetime cancer risk of 10-6 to 10-4 for protecting human health has been established by the EPA. Table 43 summarizes the cancer inhalati on risk calculations for the mean concentrations of benzene in indoor air from the study results and the mean and 95th percentile concentrations from the EPA a nd NYSDOH background studies. Study results ranged from 6.83x10-6 to 1x10-5. This range falls within EPA’s acceptable risk range for excess lifetime cancer risk. Regulatory b ackground results calculations ranged from 9.9x10-6 to 2.26x10-4. The cancer risk for the population in the study exposed to the mean concentration of benzene in indoor air was below the risk calculated for the mean and the 95th percentile concentrations of benzene in the re gulatory background studies. Table 43. Cancer Inhalation Risks for Benzene Mean Concentrations for Indoor Air from Study Results and EPA/DOH Background Indoor Air Mean Concentrations Benzene Inhalation Unit Risk 2.2x10-6 7.8x10-6 No Vadose Mean 1.93E-066.83E-06

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94 Table 43.(continued) 0-6 feet Mean 2.98E-061.06E-05 6-25 feet Mean 2.83E-061.00E-05 DOH Mean 1.83E-051.48E-05 EPA Mean 9.90E-063.51E-05 DOH 95th 6.38E-052.26E-04 EPA 95th 2.75E-059.75E-05 Table 44 summarizes the cancer risk calculations for the maximum concentrations of benzene in indoor air from the study results and the maximum and 95th percentile concentrations from the EPA and NYSDOH background studies. Study results ranged from 9.68x10-6 to 1.04x10-5. This range falls within EPA’s acceptable risk range for excess lifetime cancer risk. Regulatory b ackground results calculations ranged from 9.75x10-5 to 1.01x10-3. The cancer risk for the populat ion in the study exposed to the maximum concentration of benzene in indoor air was below the risk calculated for the maximum and 95th percentile concentrations of be nzene in the regulatory background studies. Table 44. Cancer Inhalation for Benzene Ma ximum Concentrations for Indoor Air from Study Results and EPA/DOH Background Indoor Air Maximum Concentrations Benzene Inhalation Unit Risk 2.2x10-6 7.8x10-6 No Vadose Max 9.68E-063.43E-05 0-6 feet Max 1.04E-053.68E-05 6-25 feet Max6.16E-062.18E-05 DOH Max 1.01E-033.59E-03

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95 Table 44. (continued) EPA Max 1.39E-044.91E-04 DOH 95th 6.38E-052.26E-04 EPA 95th 2.75E-059.75E-05 Table 45 summarizes the cancer risk calculations for the mean concentrations of benzene in soil vapor from the study results and the mean and 95th percentile concentrations in indoor air from the EPA and NYSDOH background studies. These calculations are based on a worse-case scen ario for soil vapor. The concentrations of benzene in soil vapor used for these calcula tions assume that the concentration of benzene in soil vapor are the same as would be found in the indoor air of a building or residence. Acceptable practice when screen ing soil vapor is to apply an attenuation factor of 0.1 to a concentration of a chemi cal detected in soil va por to estimate the potential concentration of that same chemical in the indoor air. Th e concentrations used to calculate the cancer risk for benzene from soil vapor does not use an attenuation factor. Study results ranged from 6.37x10-6 to 1.55x10-5. This range falls within EPA’s acceptable risk range for excess lifetime can cer risk. Regulatory background results calculations ranged from 9.9x10-6 to 2.26x10-4. The cancer risk for the population in the study exposed to the mean concentration of benzene in soil vapor was below the risk calculated for the mean and 95th percentile concentrations of benzene in the regulatory background studies.

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96 Table 45. Cancer Inhalation Risks for Benzene Mean Concentrations for Soil Vapor from Study Results and EPA/DOH Background Soil Vapor Mean Concentrations Benzene Inhalation Unit Risk 2.2x10-6 7.8x10-6 No Vadose Mean 2.10E-057.45E-05 0-6 feet Mean 6.37E-062.26E-05 6-25 feet Mean 4.36E-061.55E-05 DOH Mean* 1.83E-051.48E-05 EPA Mean* 9.90E-063.51E-05 DOH 95th* 6.38E-052.26E-04 EPA 95th* 2.75E-059.75E-05 Table 46 summarizes the cancer risk calculations for the maximum concentrations of benzene in soil vapor from the study results and the maximum and 95th percentile concentrations in indoor air from the EPA and NYSDOH background studies. As previously mentioned, these calculations do not consider an attenuation factor. Study results ranged from 7.04x10-6 to 4.52x10-4. The cancer risk calculated for the No Vadose maximum concentration is above the accepta ble range for excess lifetime cancer risk; however this risk calculation is still be low that of the background regulatory results. Regulatory background calculati on results ranged from 9.75x10-5 to 1.01x10-3. The cancer risk for the population in the study e xposed to the maximum concentration of benzene in soil vapor was below the ri sk calculated for the maximum and 95th percentile concentrations of benzene in indoor ai r in the regulatory background studies.

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97 Table 46. Cancer Inhalation Risks for Benzen e Maximum Concentrations for Soil Vapor from Study Results a nd EPA/DOH Background Soil Vapor Maximum Concentrations Benzene Inhalation Unit Risk 2.2x10-6 7.8x10-6 No Vadose Max 1.28E-044.52E-04 0-6 feet Max 1.80E-056.40E-05 6-25 feet Max 7.04E-062.50E-05 DOH Max* 1.01E-033.59E-03 EPA Max* 1.39E-044.91E-04 DOH 95th* 6.38E-052.26E-04 EPA 95th* 2.75E-059.75E-05 Table 47 summarizes the cancer risk calculations for the mean concentrations of benzene in outdoor air from the study results and the mean and 95th percentile concentrations in outdoor air from th e EPA and NYSDOH background studies. Study results ranged from 9.36x10-6 to 1.74x10-6. This range falls within EPA’s acceptable risk range for excess lifetime cancer risk. Regulat ory background results calculations ranged from 7.04x10-6 to 1.28x10-5. The cancer risk for the population in the study exposed to the mean concentration of benzene in outdoor ai r was similar to the ri sk calculated for the mean and 95th percentile concentratio ns of benzene in the re gulatory background studies.

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98 Table 47. Cancer Inhalation Risks for Benzen e Mean Concentrations for Outdoor Air from Study Results a nd EPA/DOH Background Outdoor Air Mean Concentrations Benzene Inhalation Unit Risk 2.2x10-6 7.8x10-6 No Vadose Mean 1.74E-066.17E-06 0-6 feet Mean 2.50E-068.87E-06 6-25 feet Mean 2.64E-069.36E-06 DOH Mean 4.18E-061.48E-05 EPA Mean 7.04E-062.50E-05 DOH 95th 1.28E-054.52E-05 EPA 95th 2.11E-057.49E-05 Table 48 summarizes the cancer risk calculations for the maximum concentrations of benzene in outdoor air from the study results and the maximum and 95th percentile concentrations in outdoor air from th e EPA and NYSDOH background studies. Study results ranged from 9.36x10-6 to 1.95x10-5. This range falls within EPA’s acceptable risk range for excess lifetime cancer risk. Regulat ory background results calculations ranged from 4.52x10-5 to 1.01x10-4. The cancer risk for the population in the study exposed to the maximum concentration of benzene in outdo or air was similar to the risk calculated for the maximum and 95th percentile concentrations of benzene in the regulatory background studies.

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99 Table 48. Cancer Inhalation Risks for Ben zene Maximum Concentrations for Outdoor Air from Study Results and EPA/DOH Background Outdoor Air Maximum Concentrations Benzene Inhalation Unit Risk 2.2x10-6 7.8x10-6 No Vadose Max 5.83E-062.07E-05 0-6 feet Max 5.50E-061.95E-05 6-25 feet Max2.64E-069.36E-06 DOH Max 3.74E-051.33E-04 EPA Max 2.86E-051.01E-04 DOH 95th 1.28E-054.52E-05 EPA 95th 2.11E-057.49E-05 Figures 33 through 38 compare the calculate d cancer risks for benzene mean and maximum concentrations from the study results to the calculated cancer risks for benzene for the mean, maximum, and 95th percentile concentrati ons in the EPA and NYSDOH background studies. As these figures dem onstrate, the cancer risks for benzene concentrations from study results are below or similar to those calcu lated from regulatory background concentrations.

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100 Inhalation Cancer Risks fo r Benzene Indoor Air Mean Concentrations 1.93E-06 2.98E-062.83E-06 3.51E-05 2.26E-04 9.75E-05 1.83E-05 9.90E-06 6.38E-05 2.75E-05 6.83E-06 1.06E-05 1.00E-05 1.48E-050.00E+00 5.00E-05 1.00E-04 1.50E-04 2.00E-04 2.50E-04 NV Mean0-6 feet Mean 6-25 feet Mean DOH Mean EPA Mean DOH 95thEPA 95th Inhalation Unit Risk 2.2x10-6 Inhalation Unit Risk 7.8x10-6 Figure 33. Inhalation Cancer Risks for Be nzene Indoor Air Mean Concentrations

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101 Cancer Inhalation Risk for Indoor Air Maximum Concentrations9.68E-061.04E-05 6.16E-06 2.75E-05 3.59E-03 4.91E-04 2.26E-04 1.01E-03 1.39E-04 6.38E-05 3.43E-053.68E-05 2.18E-059.75E-050.00E+00 5.00E-04 1.00E-03 1.50E-03 2.00E-03 2.50E-03 3.00E-03 3.50E-03 4.00E-03 NV Max0-6 feet Max6-25 feet MaxDOH MaxEPA MaxDOH 95thEPA 95th Inhalation Unit Risk 2.2x10-6 Inhalation Unit Risk 7.8x10-6 Figure 34 Inhalation Cancer Risks for Benzen e Indoor Air Maximum Concentrations

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102 Cancer Inhalation Risks for Soil Vapor Mean Concentrations4.36E-06 7.45E-05 2.26E-05 351E-05 2.26E-04 9.75E-05 2.75E-05 6.38E-05 1.83E-05 9.90E-06 6.37E-06 2.10E-05 1.48E-05 1.55E-050.00E+00 5.00E-05 1.00E-04 1.50E-04 2.00E-04 2.50E-04NV Mean0-6 feet Mean 6-25 feet Mean DOH Mean* EPA Mean*DOH 95th*EPA 95th* Inhalation Unit Risk 2.2x10-6 Inhalation Unit Risk 7.8x10-6 Figure 35. Inhalation Cancer Risks for Be nzene Soil Vapor Mean Concentrations *Comparison made to regulatory indoor air background concentrations

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103 Cancer Inhalation Risks for Soil Vapor Maximum Concentrations1.80E-05 7.04E-06 6.38E-05 2.75E-05 4.52E-04 3.59E-03 4.91E-04 1.28E-04 1.01E-03 1.39E-04 9.75E-05 226E-04 6.40E-052.50E-050.00E+00 5.00E-04 1.00E-03 1.50E-03 2.00E-03 2.50E-03 3.00E-03 3.50E-03 4.00E-03NV Max0-6 feet Max6-25 feet MaxDOH Max*EPA Max*DOH 95th*EPA 95th* Inhalation Unit Risk 2.2x10-6 Inhalation Unit Risk 7.8x10-6 Figure 36. Inhalation Cancer Risks for Ben zene Soil Vapor Maximum Concentrations *Comparison made to regulatory indoor air background concentrations

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104 Cancer Inhalation Risks for Outdoor Air Mean Concentrations8.87E-06 9.36E-06 1.48E-05 2.50E-05 4.52E-05 7.49E-05 2.11E-05 1.28E-05 7.04E-06 4.18E-06 2.64E-06 2.50E-06 1.74E-06 6.17E-060.00E+00 1.00E-05 2.00E-05 3.00E-05 4.00E-05 5.00E-05 6.00E-05 7.00E-05 8.00E-05 NV Mean0-6 feet Mean 6-25 feet Mean DOH Mean EPA Mean DOH 95thEPA 95th Inhalation Unit Risk 2.2x10-6 Inhalation Unit Risk 7.8x10-6 Figure 37. Inhalation Cancer Risks for Ben zene Outdoor Air Mean Concentrations

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105 Cancer Inhalation Risks for Outdoor Air Maximum Concentrations2.64E-06 2.07E-05 1.95E-05 1.33E-04 1.01E-04 4.52E-05 7.49E-05 5.83E-06 5.50E-06 2.11E-05 128E-05 2.86E-05 3.74E-05 9.36E-060.00E+00 2.00E-05 4.00E-05 6.00E-05 8.00E-05 1.00E-04 1.20E-04 1.40E-04 NV Max0-6 feet Max6-25 feet Max DOH MaxEPA MaxDOH 95thEPA 95th Inhalation Unit Risk 2.2x10-6 Inhalation Unit Risk 7.8x10-6 Figure 38. Inhalation Cancer Risks for Ben zene Outdoor Air Maximum Concentrations

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106 Chapter Five Discussion and Conclusions The purpose of this research was to eval uate the potential public health risks associated with former MGP sites to the human population located in residences and businesses adjacent to or overlying these cont aminated sites. This study identified the contaminants present in the soil vapor, the indoor air, and the ambient outdoor air of residences and commercial buildings and evaluated whether the presence of these chemical contaminants in the indoor air were the result of soil vapor intrusion. In addition this research identified the potential public health risks posed by these contaminants and evaluated whether the hum an population adjacent to the former MGPs was at greater risk of adverse health eff ects than that of a normal resident in the northeastern US. Analysis of the data collected to evalua te the potential for so il vapor intrusion of MGP-related chemicals concluded that no in trusion had occurred. Concentrations of chemicals detected in indoor air were an order of magnitude below published reference concentrations. Based on the analyses of th is data the five chemicals with highest frequency of detection in th e study results, benzene, toluen e, ethylbenzene, m,p-xylene, and o-xylene, were more frequent in outdoor air than in indoor air and soil vapor. A confounding factor in the determination of soil vapor intrusion is that many of the chemicals associated with MGPs are pe troleum-related, and ar e ubiquitous in the

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107 environment and present in many common househol d products. This is true with any soil vapor intrusion assessment. On the other ha nd, soil vapor intrusion could be masked by the use of household products that contai n the same chemical composition of the contaminant source. Based on the informati on uncovered in the pre-assessment interview and questionnaire, product invent ory, and field observations, th e risk assessor often has to determine whether what is being observed in in door air is a result of soil vapor intrusion or from products that are in use in the building or from ambient outdoor sources. As previously mentioned, the presence of chemicals in soil vapor does not, by default, mean that these chemicals will in trude into indoor air. Often chemical concentrations in the building are higher than those in soil vapor indicating that soil vapor intrusion has not occurred. In fact the opposite might be true that indoor air quality has affected soil vapor. In addition, soil vapor intr usion does not occur pref erentially, meaning one chemical will move into the building when others do not. Assessment of intrusion is holistic; the risk assessor must evaluate the movement of multiple volatile organic chemicals into indoor air from soil va por to conclude vapor intrusion. Federal and state regulatory agencies have conducted studies to establish background data for indoor air and outdoor air, yet while industry is spending millions of dollars in investigating and mitigating soil vapor intrusion, no background numbers exist for soil vapor. While EPA recommends the appl ication of attenuation fa ctors to soil vapor concentrations determine potenti al concentrations in indoor air, many regulatory agencies are reluctant to accept these attenuated numbers and require indoor air sampling. As this

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108 study reports, money is spent to investigat e and potentially remediate concentrations which are below background re gulatory concentrations. The majority of the buildings and residen ces in this study were built in the late 1950s to early 1960s; however some of these bui ldings were over 100 years old. Most of the structures had concrete floors in the ba sements, but some only had dirt floors or crawlspaces. Although the age and type of c onstruction of these structures would seem to increase the risk factors for soil vapor intr usion, this was not observed. A number of issues played a potential role in preventing soil vapor intrusion. Firs t, a clean layer of groundwater existed between the buildings a nd the contaminant plumes. Second, natural attenuation occurs for volatile organic ch emicals, especially the BTEX compounds, and some of the semi-volatile chemicals. Many bact eria use contaminants as the sole source of carbon and energy (Vivaldi, 2001 ). And third, the construc tion of the structures was not air-tight, and although this could increase the chance for soil vapor intrusion, it also may play a role in dilution of indoor air. As we have seen in this study a number of the chemicals detect ed in indoor air were attributed to the household or comm ercial products used in the buildings. Risk assessment methodologies were us ed to evaluate whether residents and occupants of commercial buildings adjacent to or overlying former MGP sites were at greater risk of adverse health effects than that of a normal resident in the northeastern US. This assessment found exposures to the study population were less than or similar to background. Hazard Indices were calculated to estim ate the risk of non-carcinogenic health effects. EPA’s Risk Assessment Guidelines (1989) state:

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109 Another limitation with th e hazard index approach is that the assumption of dose additivity is most properly applied to compounds that induce the same effect by the same mechanism of action. C onsequently, application of the hazard index equation to a number of compounds that are not expected to induce the same type of effects or that do not ac t by the same mechanism could overestimate the potential for effects, although such an approach is appropriate at a screening level. This possibility is generally not of concern if only one or two substances are responsible for driving the HI above unity. If the HI is greater than unity as a consequence of summing several hazard quot ients of similar value, it would be appropriate to segregate the compounds by effect and by mechanism of action and to derive separate hazard indices for each group With these limitations in mind the calcu lated HIs for the study group were less than the HIs calculated with regula tory background concentrations. Calculations to determine the potential for non-carcinoge nic health risks to the occupants of residents and commercial buildings found HIs below 1 for the mean and maximum concentrations of the study result s for indoor air and out door air regardless of the thickness of the vadose zone (depth to groundwater). Benzene was the largest contributor to non-carcinogeni c hazards for both the study results and the regulatory results. The HIs for the mean concentrations so il vapor and the maximum concentrations for soil vapor for the 0-6 feet and 6-25 feet thick vadose zones were below 1. Only the maximum concentration for soil vapor with no vadose zone was above 1 with a calculated HI of 2.41. Benzene, with a HQ of 1.93, was the driver for this HI, however

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110 this exceedance was not seen in either no va dose zone mean or maximum indoor air HIs indicating soil vapor was not intruding into indo or air. The calcula ted HIs for the study results were similar to the HIs calculate d for the EPA and DOH background studies. Use of health protective risk assessment procedures as descri bed in the cancer guidelines means that estimates, while uncerta in, are more likely to overstate than understate hazard and/or risk (EPA, 2005). Still using this risk assessment methodology the cancer risk calculations for inhalation of benzene for the study concentrations were below or similar to regulatory background cance r risks. As the results show exposure to benzene from the study results were belo w levels protective of human health. Calculations to determine the potential fo r carcinogenic health risks from benzene to the occupants of residents and co mmercial buildings ranged from 9.75x10-6 to 4.52x10-4. However background benzene exposure not related to former MGP sites ranged from 9.9x10-6 to 3.59x10-3. The highest cancer risk in the study results was 4.52x10-4 for the maximum concentration of ben zene in soil vapor with no vadose zone. This calculation is based on the assumption that the benzene concentration would be directly inhaled by the occupa nt. If an attenuation factor of 0.1 was applied to the maximum concentration of benzene in soil va por the actual concentration used for the cancer calculation would be 0.82 ug/m3. This attenuated concentr ation would result in a cancer risk range of 6.4x10-6 to 1.8x10-6, well within EPA’s acceptable risk range for excess lifetime cancer risk. In conclusion, cancer risk and exposures to indoor air, soil vapor or ambient air concentrations were equivalent or less than a normal resident in the northeast United States. No increased public health risks were associated with occupied residential or

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111 commercial properties over lying or surrounding MGPs.

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112 List of References Agency for Toxic Substances and Disease Registry, (1997). Toxicological Profile for Benzene. Update (Final Report) pp. 459 NTIS Accession No. PB98-101157. Atlanta, GA: Author. Agency for Toxic Substances and Disease Registry, (2000) Toxicological Profile for Toluene September, 2000: Author. Agency for Toxic Substances and Disease Registry, (2007) Toxicological Profile for Benzene August, 2007: Author. Agency for Toxic Substances and Disease Registry, (2007a) Toxicological Profile for Ethyl benzene, September, 2007: Author. Agency for Toxic Substances and Disease Registry, (2007b) Toxicological Profile for Xylene, August, 2007: Author. Agency for Toxic Substances and Disease Registry, (2008) http://www.atsdr.cdc.go v/glossary.html#G-M(accessed September 7, 2008) Agency for Toxic Substances and Disease Registry, (2008a) http://www.atsdr.cdc.gov/s ubstances/toluene/index.html (accessed September 8, 2008). Bardod j, Z., Crek, A., (1988). Long-term Study on Workers Occupationally Exposed to Ethylbenzene. Journal of Hygiene, Epidemiology, Microbiology and Immunology, 32 (1):1-5. Electric Power Research Institute, (1999) Remediation of Gas Holders at MGP Sites: A Manual of Practice, EPRI TR-111689, GRI-99/0239, Final Report, December 1999. Electric Power Research Institute, (2008). 50 MGP Site Management Portfolio, 2008: Author. Fishbein, L., (1985). An overview of envi ronmental and toxicological aspects of aromatic hydrocarbons. III. Xylene. Science of the Total Environment, 43 (1-2):165-83.

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113 Fishbein, L. (1985a) An overview of envi ronmental and toxicological aspects of aromatic hydrocarbons. IV. Ethylbenzene Science of the Total Environment, 44 (3):26987. Fisher, C., Schmitter, R., and Lane, E., (1999). Manufactured Gas Plants: The Environmental Legacy South & Southwest Hazardous Substance Research Center, Georgia Institute of Technology, Atlanta, GA. Harbison, R.D. (1998) Hamilton and Hardy’s Industrial Toxicology Mosby-Year Book, Inc., N.Y. Harkins, S.M., Truesdale, R.S., Hoffman, P., Winters, S. (1986). U.S. Production of Manufactured Gases: Assessmen t of Past Disposal Practices Research Triangle Institute, Research Triangle Park, NC. http://www.britannica.com/ EBchecked/topic/621445/vadosezone#tab=active~checked%2Citems ~checked&title=vadose%20zone%20-%20Britannica%20Online%20Encyclopedia (accessed August 30, 2008). International Agency for Research on Cancer, (2000). Ethylbenzene Monograph, Volume 77, 2000 : Author International Agency for Research on Cancer, (2008). http://monographs.iarc.fr/ENG/Classification/index.php (accessed September 7,2008). Integrated Risk and Information System, (2008)., U.S. EPA, http://www.epa.gov/ncea/iri s/help_ques.htm#whatiris (accessed September 6, 2008). Johnson, P.C., Ettinger, R.A., Kurtz, J., Bryan, R., and Kester, J.E., (2002). Migration of Soil Gas Vapors to Indoor Ai r: Determining Vapor Attenuation Factors Using a Screening-Level M odel and Field Data from the Cdot-Mtl Denver, Colorado Site American Petroleum Institute. Khan, A.H., (2007) Benzene’s toxicity: A consolidated short review of human and animal studies. Human and Experimental Toxicology, 26 : 677–685. Langman, J.M., (1994). Xylene: its toxici ty, measurement of exposure levels, absorption, metabolism and clearance. Pathology ; 26 (3):301-9. National Institute of Occupationa l Safety and Health, (2005). Pocket Guide to Chemical Hazards, npgd0049, Benzene, September, 2005 : Author.

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114 National Library of Medicine, (2005). Benzene, Hazardous Substances Databank Number : 35 Last Revision Date: 20050624. National Research Council, (1983). Risk Assessment in the Federal Government: Managing the Process. Committee on the Institutional Means for Assessment of Risks to Public Health, Committee on Life Sciences, National Academy Press, Washington, D.C. National Toxicology Program, (2005). Report On Carcinogens, Benzene, Eleventh Edition : Author New York State Departme nt of Health, (2006). Guidance for Evaluating Soil Vapor Intrusion in the State of New York, October 2007. Center for Environmental Health, Bureau of Environmental Ex posure Investigation: Author. Persad, A.S., and Cooper, G.S., (2008). Use of Epidemiological Data in Integrated Risk Information System (IRIS). Toxicology and Applied Pharmacology January 31, 2008. Ruijten, M.W., Hooisma, J., Brons, J.T., Habets, C.E., Emmen, H.H., Muijser, H. (1994). Neurobehavioral effects of long-term exposure to xylene and mixed organic solvents in shipyard spray painters. Neurotoxicology, 15 (3):613-20. SRI Consulting, 2006. Directory of chemical pro ducers: United States of America. Menlo Park, CA. United States Environmental Protection Agency, (1989) Risk Assessment Guidance for Superfund. United States Environmental Protecti on Agency, (1991). Integrated Risk Information System (IRIS) Toxicological Profil e 0051, Ethyl benzene. United States Environmental Protection Agency, (1992). Guidelines for Exposure Assessment Published on May 29, 1992, Fede ral Register 57(104):22888-22938 United States Environmental Protection Agency, (1998). Carcinogenic Effects of Benzene: An Update. National Center for Environmental Assessment–Washington Office, Office of Research and De velopment, Washington, DC: Author.

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115 United States Environmental Protection Agency, (1999). Compendium of Methods for the Determination of Toxic Organic Co mpounds in Ambient Air, Second Edition, Compendium Method TO-15 Determination Of Volatile Organic Compounds (VOCs) In Air Collected In Specially-Prepared Canisters And Analyzed By Gas Chromatography/Mass Spectrometry (GC/MS), Center for Environmental Research Information, Office of Research and De velopment, Cincinnati, OH: Author. United States Environmental Protection Agency, (1999a). A Resource for MGP Site Characterization and Remediation Ex pedited Site Characterization and Source Remediation at Former M anufactured Gas Plant Sites Office of Solid Waste and Emergency Response, (5102G): Author. United States Environmental Protection Agency, (2000). Air Toxics Facts Sheet, Benzene. United States Environmental Protection Agency, (2001). Building Assessment and Survey Evaluation (BASE 1994-1996). United States Environmental Protection Agency, (2002). Toxicological Review of Benzene (Noncancer Effects) (CAS No. 71-43-2) In Support of Summary Information on the Integrated Risk In formation System (IRIS) EPA/635/R-02/001F. United States Environmental Protection Agency, (2002a). Draft Guidance of Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion) Office of Solid Waste and Emergency Response (OSWER), Washington, DC: Author. United States Environmental Protecti on Agency, (2003). Integrated Risk Information System (IRIS) Toxicological Profile 0276, Benzene. United States Environmental Protecti on Agency, (2003a). Integrated Risk Information System (IRIS) Toxicological Profile 0270, Xylene. United States Environmental Protection Agency, (2004). Cleaning Up the Nation’s Waste Sites: Markets and Technology Trends Office of Solid Waste And Emergency Response, 542-R04-015 (5102G): Author. United States Environmental Protecti on Agency, (2005). Integrated Risk Information System (IRIS) Toxicological Profile 0118, Toluene. United States Environmental Protection Agency, (2005a). Guidelines for Carcinogen Risk Assessment Risk Assessment Forum, Washington, DC: Author.

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116 United States Environmental Protection Agency, (2005b). USEPA Contract Laboratory Program National Functional Guidelines for Organic Data Review January 2005: Author. United States Environmental Protec tion Agency, (2008). IRIS Frequent Questions, http://www.epa.gov/ncea/iri s/help_ques.htm#whatiris (accessed September 6, 2008). Vidali, M., (2001). Bioremediation. An overview. Pure and Applied Chemistry 73 7:pp. 1163–1172.

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117 Bibliography http://www.dec.ny.gov/chemical/24922.html (accessed August 31, 2008). International Agency for Research On Cancer, (2006). IARC Monographs on the Evaluation of Carcinogenic Risks to Humans Lyon, France: Author. International Agency for Research on Cancer, (1989). Xylenes Monograph, Volume 71, 1989: Author Interstate Technology and Regulatory Council, (2007). Investigative Approaches for Typical Scenarios, A Supplement to Vapor Intrusion Pathway: A Practical Guideline, January 2007 ITRC Vapor Intrusion Team. National Institute of Occupationa l Safety and Health, (2003). Benzene, Registry of Toxic Effects of Chemical Substances: Author. Savitz, D. A. and Andrews, K. W. (1 997). Review of Epidemiologic Evidence on Benzene and Lymphatic and Hematopoietic Cancers. American Journal of Industrial Medicine, 31 (3): 287-95. United States Environmental Protection Agency, (2005). Supplemental Guidance for Assessing Susceptibility from Early-Life Exposure to Carcinogens, March, 2005 Risk Assessment Forum, Washington, DC: Author. United States Environmental Protection Agency, (1992). Guidelines for Exposure Assessment, May 29, 1992 Federal Register 57(104):22888-22938: Author. United States Environmental Protection Agency, (1991). Guidelines for Developmental Toxicity Risk Assessment, December 5, 1991 Federal Register 56(234):63798-63826: Author.

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About the Author Robin Brewer DeHate received her Bachel or’s Degree in Environmental Health Science in 1983 from Eastern Kentucky Univ ersity. She completed her MPH in Safety Management at the University of South Flor ida in 2003 and entered the Ph.D. program in Toxicology and Risk Assessment. With over 25 years experience in the envi ronmental and occupational health field, Mrs. DeHate was formerly the president of a company specializing in the performance of occupational and environmental assessments and the development of occupational and environmental training programs for private industry and government agencies. She is currently the Senior Risk Mana ger and Corporate Health and Safety officer for a national environmental, geo-technical and water resources firm. She is a frequent lecturer at the USF College of Public Health and has been a presenter at national and international technical conferences. She is the coauthor of seven publications and abstracts.


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Evaluation of the public health risks associated with former Manufactured Gas Plants
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ABSTRACT: Regulatory agencies have recently focused on assessing the potential for soil vapor intrusion (SVI) and risk posed to occupants of residential and commercial properties overlying and surrounding former Manufactured Gas Plants (MGPs). This study evaluated the potential for SVI at 10 commercial buildings and 26 single family and multi-family residential properties overlying and/or adjacent to three former MGPs. The potential for SVI exposure was categorized into three groupings according to thickness of the vadose zones: no vadose zone; 0 6 feet thick, and 6 to 25 feet thick. Indoor and outdoor air and soil vapor samples were collected and analyzed for VOCs by the USEPA Method TO-15. These findings were compared to federal and state regulatory background data sets. The results did not identify evidence of MGP-related soil vapor intrusion from any of the 36 sites regardless of depth to water table or proximity to MGP source tar or dissolved phase plumes.In addition, comparative risks were calculated based on maximum and mean concentrations for benzene, toluene, ethylbenzene, and xylenes measured in ambient air samples, soil vapor, and indoor air. These chemicals were selected based on frequency of detection within the data sets. Hazard Indexes were calculated using the study results and the mean, maximum and 95th percentile concentrations from regulatory data bases. Carcinogenic risks associated with benzene were calculated using both the measured mean and maximum study results and the mean, maximum and 95th percentile concentrations from state and federal data bases. The calculated Hazard Indexes were less than 1 or were comparable to the regulatory mean and maximum background levels. Calculated cancer risks for residential and occupational exposures ranged from 9.75x10 to 4.52x10. However background benzene exposure not related to former MGP sites ranged from 9.9x10 to 3.59x10.Cancer risk and exposures to indoor air, soil vapor or ambient air concentrations were equivalent or less than a normal resident in the northeast United States. No increased public health risks were associated with occupied residential or commercial properties overlying or surrounding MGPs.
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