PUBLIC HEALTH ASSESSMENT
RICKENBACKER AIR NATIONAL GUARD BASE (USAF)
(a/k/a RICKENBACKER AIR FORCE BASE)
COLUMBUS, FRANKLIN COUNTY, OHIO
Rickenbacker Air National Guard Base (RANGB) is a military installation near Columbus, Ohio. This military facility first opened in 1942 to provide basic pilot training and military support. During its peak years in the 1970s, the facility (then known as Rickenbacker Air Force Base) covered approximately 4,129 acres and supported 5,000 employees. In 1980, the Department of Defense closed Rickenbacker Air Force Base, disposed of its excess property, and transferred the remaining management and operation responsibilities to the Air National Guard. After property transfers and sales resulting from the closure were completed in 1984, RANGB covered 2,016 acres. A significant, further down-sizing occurred on September 30, 1994, when RANGB was realigned and reduced to 164 acres. Currently, the base is surrounded primarily by agricultural areas, but hosts a number of diverse commercial and industrial facilities.
In January 1994, RANGB was proposed for listing on the United States Environmental Protection
Agency 
National Priorities List because of contamination detected in the base groundwater and
surface water. Past base operations and waste handling practices resulted in contamination of site
media by volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs),
polycyclic aromatic hydrocarbons (PAHs), and metals at 44 sites and the Rickenbacker Landfill
being investigated under the Department of Defense's Installation Restoration Program (IRP).
In the past, community members have expressed concern about potential health effects associated
with site contaminants in groundwater, surface water, soil, and locally-caught fish. The Agency
for Toxic Substances and Disease Registry (ATSDR) conducted site visits in 1994 and 1999,
spoke with local community members, and reviewed and evaluated groundwater, surface water,
sediment, soil, and local fish data. In this public health assessment, ATSDR reviews groundwater,
surface water, sediment, soil, and biota data for the current RANGB facility, as well as for land
that was formerly owned by the military but is no longer RANGB property.
At seven RANGB sites and the Rickenbacker Landfill, groundwater contains VOCs, SVOCs, and/or metals above ATSDR health-based comparison values. Appendix A presents the specific site locations, detected contaminant concentrations, and respective comparison values for RANGB. There was no past exposure to this groundwater contamination because on-site military wells and off-site municipal and private drinking water supply wells were either upgradient or drew from uncontaminated groundwater sources. Currently, all on-site and off-site water is supplied by municipal water sources. The military and municipal wells are routinely tested and private wells are periodically tested. All drinking water supplies meet federal and state drinking water standards.
Local surface water is relatively uncontaminated, but sediment in the RANGB drainage ditches (Sites 25 and 27) contains some contaminants that exceed ATSDR comparison values, including VOCs, SVOCs, PAHs, pesticides, and metals. Local surface waters are not used for drinking water, although people recreationally fish in area creeks and rivers. Public exposure (past, current, and future) to surface water and sediment, however, is minimal, if it occurs at all, and therefore does not present a public health hazard.
ATSDR evaluated surface soil data for all 44 IRP sites and the Rickenbacker Landfill. Although contaminants at some IRP sites exceeded ATSDR comparison values for soil, these sites are infrequently, if ever, contacted by the public. Incidental, infrequent exposure will not result in adverse health impacts. Other sites were not contaminated by RANGB activities. IRP sites are not associated with any known public health hazards because: 1) no site-related contaminants are present; 2) contaminant concentrations detected are too low to pose a health hazard; and/or 3) past and current exposures to the general public have been prevented through land use restrictions and/or remedial activities. At IRP sites where soil contamination has the potential to impact underlying groundwater, soil removal activities have or will further reduce contaminant concentrations and the potential for their migration to groundwater.
Limited sampling analyses at Rickenbacker Landfill have detected only low levels of surface soil contamination, not sufficient to suggest a potential public health hazard. However, environmental contamination has not been fully characterized at the landfill. ATSDR identified infrequent incidental exposure to trespassers as a potential pathway. Until more data become available, ATSDR concludes that Rickenbacker Landfill poses an indeterminate public health hazard.
ATSDR found no public health data or community health problems to indicate that local fish are unsafe for human consumption. To date, no fish tissue samples have been analyzed, but available ecological quality information indicates the water and sediment contamination are insufficient to likely contaminate fish. Therefore, the consumption of local fish poses no apparent public health hazard. If and when more information becomes available, ATSDR will assess the data and reevaluate its conclusion, if necessary.
ATSDR concludes that there is no public health hazard associated with on- and off-base groundwater and surface water because exposures are unlikely to occur. Based on the environmental sampling available since the mid 1980s, ATSDR concludes that no apparent public health hazards are associated with on-site drainage ditch sediments, IRP site soils, and locally-caught fish because exposures to contaminated media are extremely limited, if they occur at all, and/or contaminant levels are well below those expected to present a possible public health hazard. Rickenbacker Landfill poses an indeterminate public health hazard because the nature and extent of landfill contamination has not been fully characterized.
Table 1. Exposure Hazards Summary--Rickenbacker Air National Guard Base (RANGB)
| Exposure Scenario | Time Frame | Exposure Yes/No |
Hazard | Actions Taken/Recommended |
| Exposure to groundwater underlying RANGB | Past Current Future |
Past, current, and future: No | No hazard | • To prevent potential future exposures, the Air Force is remediating groundwater at Site 2; removing contaminated soil at Sites 21, 41, 42, and 43; and assessing the potential need for remedial actions at Sites 1 and 12. |
| Exposure to off-base groundwater | Past Current Future |
Past, current, and future: No | No apparent hazard | • To prevent potential future exposures, the Air Force is remediating groundwater at Site 2; removing contaminated soil at Sites 21, 41, 42, and 43; and assessing the potential need for remedial actions at Sites 1 and 12. |
| Dermal contact with surface water and sediments, both on- and off-site | Past Current Future |
Past, current, and future: Minimal exposure, if any, to surface water and sediment. Local residents do not swim or drink from surface waters. | Surface water: No hazard
Sediment: No apparent hazard |
• No surface water actions are necessary to protect public
health.
• For sediment in on-base ditches, the Air Force recommends no further action status. The regulatory agencies recommend conducting toxicity testing, a feasibility study, or "hot spot removal" actions. |
| Dermal contact with surface soil at IRP sites | Past Current Future |
Past, current, and future: Minimal exposure, if any, to contaminated soil. | No apparent hazard | • The Air Force has or will remove contaminated soils
from Sites 21, 41, 42, and 43 because of the potential for contaminants
to leach into underlying groundwater. • The Air Force is assessing the potential need for remedial actions at Sites 1 and 12. |
| Dermal contact with surface soil at Rickenbacker Landfill | Past Current Future |
Past, current, and future: Possible infrequent incidental exposure (trespassers) | Indeter-minate hazard | • The United States Army Corps of Engineers (USACE) is
conducting environmental investigations to assess the nature and extent
of contamination. • USACE will perform all necessary interim and remedial actions to protect human health. |
| Consumption of locally caught fish | Past Current Future |
Past, current, and future: Unlikely | No apparent hazard | • No actions are necessary to protect public health. |
Originally known as the Northeastern Training Center of the Army Air Corps and later renamed Lockbourne Air Force Base (AFB), this military facility was officially named Rickenbacker AFB (RAFB) in 1974 and renamed Rickenbacker Air National Guard Base (RANGB) in 1980.(1) RANGB is a closed military base, although it still stations several active military units. Currently, RANGB consists of approximately 2,000 acres with a runway and airfield area, industrial areas, recreational facilities, and housing units. It is located approximately 12 miles southeast of downtown Columbus, Ohio, and one-half mile east of the village of Lockbourne, Ohio (Figure 1). Surrounded by flat, agricultural lands, RANGB lies in Pickaway and Franklin Counties, Ohio.
RANGB has been in operation since the early 1940s to support training and air-to-air refueling operations. RANGB was officially activated in 1942 as a pilot training center for the Army Air Corps. At that time, it encompassed 1,574 acres. In 1949, the base was deactivated by the Air Force and used as an Ohio Air National Guard (OHANG) training base for 18 months. In January 1951, however, RANGB responded to the Korean Conflict by reactivating its role as an Air Force installation. RANGB acquired additional properties and expanded its pilot training and Air Force operations to cover 4,129 acres (IT Corp. 1996a, b). Until 1980, RANGB supported a variety of military missions: operations, maintenance, personnel support, aircrew training, aircraft housing facilities, equipment storage, cargo activities, airlift and refueling, and aerial pesticide spraying.
In April 1980, RAFB was closed and turned over to OHANG (IT Corp. 1996a, b). After this conversion, portions of the base were no longer necessary for military purposes, so the newly formed Rickenbacker Port Authority (RPA) began overseeing land reuse opportunities. During the 1980s, about 2,082 acres of the military base were excessed. Of this, 415 acres were sold to private developers, 24 acres were transferred to the U.S. Navy, and 1,642 acres were acquired by the RPA through an airport public benefit transfer. In 1981, an Aerial Spray Branch, responsible for aerial pesticide spraying missions at other bases around the country, was located at RANGB. It remained at RANGB during the next decade.
In 1991, the Department of Defense identified RANGB as a candidate base for closure under their Base Realignment and Closure (BRAC) program (Parsons 1995) and directed the Air National Guard and Air Force Reserve units to relocate to Wright-Patterson AFB, Ohio. In July 1993, however, the BRAC commission reversed its decision and allowed the Air National Guard units to remain at RANGB. The realignment was completed in September 1994, after which RANGB became a 164-acre Department of Defense owned cantonment within the Rickenbacker Airport vicinity. Also in 1994, the U.S. Army Reserve and the Ohio Army Guard moved units to land parcels adjacent to RANGB.
An official reuse plan, entitled The Disposal-Record of Decision for RANGB, was developed by the Air National Guard, Air Force, and RPA, and signed in May 1995. Following closure, RPA will manage most of the former base property as an air-cargo airport (Parsons 1995). Once RANGB reuse plans are finalized and fully implemented, the military will occupy a relatively small portion of an approximately 3,000-acre, civilian airport managed by RPA. Portions of the base will be developed for industrial and commercial uses. None of the current base property is planned for residential housing reuse purposes.
Presently, the OHANG, Ohio Army National Guard (OARNG), Naval Reserve, and Army Reserve operate small units out of RANGB. One Air National Guard unit, the 121 Air Refueling Wing (formed from a 1994 merger of the 121st Fighter Wing with the 160th Air Refueling Group) remains in a centralized military retained development area on base. The OHANG unit uses 179 acres, known as the Cantonment, and OARNG occupies 129 acres, known as the Enclave. These two areas will remain under ownership of the federal government (Parsons 1995). Figure 2 shows the layout of the base and its surrounding vicinity.
As a result of past waste and resource management practices at RANGB, some areas of the base
have become contaminated by various hazardous substances. Waste producing activities include
aircraft and vehicle maintenance, pesticide application, and painting and stripping operations. The
base also contains a landfill, fuel/oil storage areas, wastewater treatment centers, and fire
protection training areas. The primary contaminants of concern are solvents and pesticides. Other
contaminants of concern include dioxins and metals. Most contamination is contained within the
industrial areas of RANGB property and the Rickenbacker Landfill. No off-site contaminants
have been detected above trace levels, although some on-site contaminants (e.g., at Sites 1 and 2)
may have the potential to migrate off base via groundwater.
Remedial and Regulatory History
Numerous investigations have been conducted, or are ongoing, at RANGB to determine the extent of environmental contamination associated with base activities. To date, such investigations include a comprehensive Underground Storage Tank program, a base-wide asbestos survey, preliminary assessments (PAs), site investigations (SIs), a remedial investigation (RI), and a feasibility study (FS). The Air Force, OHANG, OARNG, Ohio Environmental Protection Agency (OEPA), United States Environmental Protection Agency (USEPA), and United States Army Corps of Engineers (USACE) are working together to characterize and address environmental concerns.
The Installation Restoration Program (IRP) at RANGB was initiated in 1986 when the PA identified 27 potential sites of contamination (HMTC 1987). These sites are listed in Appendix A. Five of these sites (Sites 7, 8, 11, 13, and 18) were eliminated from consideration based on the findings of the PA. Site 7 was eliminated from further investigation because no contamination was discovered associated with the fuel storage tanks at Building 901. The USACE, however, continues to investigate, review, and will remediate (if necessary) the area surrounding Site 7, specifically the former Lockbourne Air Force Base Landfill (Rickenbacker Landfill). PA activities could not physically locate Site 8 and it was designated a no further action (NFA) site. Site 11 was removed from the PA because records indicate that spilled fuel was recovered and the contaminated soil was excavated. Site 13 was removed from the PA because the spilled fuel was consumed by a fire resulting from an RB-47 aircraft crash. Site 18 was not part of the PA because no leakage was known to have occurred at the site and, when the site was inspected by Hazardous Materials Training Center personnel, all barrels were in good condition. The 22 remaining IRP sites were investigated during the SI conducted in 1988 and 1989 (ES 1994). Additional sampling was later done at Sites 7 and 18 and confirmed that these sites required no additional investigation. RANGB conducted a Phase I RI Data Collection effort from 1993 through April 1994 to further evaluate 15 sites investigated during the SI. The RANGB base drainage ditches (Sites 25 and 27) have been proposed for future investigation and remediation. A BRAC Clean-up Team (BCT), consisting of Air Force, USEPA, and OEPA representatives, is currently discussing contaminated ditch sediment issues.
An environmental baseline survey (EBS) for RANGB was completed in 1993 to review site information and further characterize soil and groundwater contamination (SAIC 1993). In 1995, a Phase II EBS was conducted at RANGB to investigate sites identified in the EBS or by base personnel as requiring investigation (IT Corp. 1996b). The Phase II RI was conducted in 1996 at 14 sites. These investigations identified five sites that required remediation. A proposed plan has been prepared for the remediation of these five sites. The remaining sites are either slated for a NFA decision document or are being investigated under the Ohio Bureau of Underground Storage Tank Regulations (BUSTR) or the Resource Conservation and Recovery Act (RCRA). Appendix A provides further details on all 44 IRP sites that have been identified and characterized throughout the years. Appendix A lists 45 individual sites, but RANGB consolidated Site 27 into Site 25, thereby creating a total of 44 IRP sites.
RANGB was proposed for inclusion on the USEPA's National Priorities List (NPL) in January 1994. At the present time, RANGB has not been finalized as a NPL site .
RANGB does not have a Federal Facilities Agreement or State Administrative Orders on Consent. However, the Base Closure and Realignment Executive Order 12580 requires that all work done at a federal facility site be consistent with the Comprehensive Environmental Response, Compensation, and Liability Act (i.e., Superfund) and the National Oil and Hazardous Substance Pollution Contingency Plan. A Department of Defense/State Memorandum of Agreement exists for the site which states that OEPA and Department of Defense will jointly maintain oversight of the investigation and remedial work conducted at RANGB (IT Corp. 1998).
Currently, environmental investigations and remedial efforts at RANGB are being conducted under the IRP, RCRA regulations, and BUSTR rules. RANGB has published decision documents for all NFA IRP sites. In October 1998, a Final FS study was published to present alternatives for remediation of five IRP sites (Sites 2, 21, 41, 42, and 43). The Air Force then developed the Remedial Action Decision Document, including minutes of a public meeting, written comments, and a responsiveness summary for the five sites moving forward into the remedial design/remedial action stage. The Air Force, USEPA, and OEPA signed a Remedial Action Decision Document for Sites 2, 21, 41, 42, and 43 on October 14, 1999, approving the most feasible approaches to ensure adequate protection of human health and the environment. The Design Documents for the remedial activities were completed on October 21, 1999. The Air Force is currently working on the Remedial Action Work Plans and plans to begin work in fiscal year 2000. The Air Force will enforce on-base deed restrictions to protect public health at Sites 2, 21, 31, 32, and 42, including the prohibition of drinking underlying UWBZ water and drilling wells near groundwater plumes (Friedstrom 2000). Two other sites, Sites 1 and 12, may require remedial actions and future deed restrictions to prevent potential public exposures.
Unlike the IRP sites, Rickenbacker Landfill is in a different environmental investigation and remediation process under the Formerly Used Defense Site (FUDS) program. The USACE, rather than by RANGB, currently oversees Rickenbacker Landfill environmental investigations and will carry out any necessary remediation activities at the landfill to protect public health.
To characterize the population and identify the presence of sensitive subpopulations, such as young children, in the vicinity of RANGB, the Agency for Toxic Substances and Disease Registry (ATSDR) examines the demographics of the nearby communities. This information also provides detail on residential history in a particular area that helps ATSDR assess time frames of potential human exposure to contaminants. The demographic and housing data for RANGB and the surrounding areas, particularly the areas west and southwest of the site where groundwater and surface water contamination may have migrated, are presented in this section. The demographics are based on U.S. Census data from 1990.
Most of RANGB lies within southeastern Franklin County, population 961,437. The remaining portion of the base stretches into northern portions of Pickaway County, population 48,255. The nearest population centers, measured in miles from the nearest edge of the base, include residential housing (immediately north), the village of Lockbourne (approximately 0.5 miles to the west), Duvall (approximately 1.5 miles to the south), Groveport (approximately 1.5 miles to the northeast), Canal Winchester (approximately 5 miles to the northeast), and Columbus (approximately 12 miles to the northwest) (IT Corp. 1998).
During peak operations in the mid-1970s, approximately 5,000 employees worked on base (Friedstrom 1999). In 1984, all RANGB on-site housing was sold and transferred by the Air National Guard and Air Force to corporate buyers. Currently, two housing areas on (former) RANGB property are in use. The village of Lockbourne, one civilian subdivision, several trailer parks, and scattered houses lie within a one-mile radius of the base perimeter (IT Corp. 1998).
Natural Resources and Land Use (Reuse Plan)
Some limited wooded areas, typically associated with surface drainage areas, occur around RANGB (IT Corp. 1998). The predominant surface water bodies near the base are Little Walnut Creek to the east and Big Walnut Creek to the west. The base is located on a till plain separating the Big Walnut Creek and Little Walnut Creek Drainage Basins. A portion of the old Ohio Canal runs to the west of RANGB, where several locks are still present (IT Corp. 1996a).
Land use adjacent to the original RANGB property is commercial, industrial, residential and agricultural. Industrial and residential properties lie primarily to the north and west of RANGB, while most other surrounding areas are comprised largely of agricultural and vacant land (Parsons 1995). A large portion of the area surrounding RANGB supports an agricultural economy, but the base itself sustains commercial and industrial uses. Remaining adjacent property to the northeast belongs to several private owners.
Prior to 1993, the underlying groundwater supplied all military, municipal, and private production wells in the area. Irrigation water also comes from underlying groundwater. In 1993, however, RANGB and the village of Lockbourne began receiving potable water from the city of Columbus Municipal Water System. Some off-base homeowners still obtain their drinking water from private wells. Six formerly-used on-base water supply wells have been abandoned and closed in accordance with OEPA regulations, due to the base realignment, declining personnel, and the cost of maintaining the wells (ATSDR 1995). A seventh well, located at the former RANGB golf course clubhouse and sold to private developers in the 1980s, continues to be used by golf patrons. This well draws water from the uncontaminated intermediate aquifer.
In the RANGB vicinity, several surface water bodies support recreational fishing activities (IT Corp. 1998). Big Walnut Creek lies approximately three quarters of a mile (at its closest point) to the west of the base. Little Walnut Creek lies approximately one-third mile (at its closest point) to the east of the base (IT Corp. 1998).
Since the 1980s, many areas of the original base have been relinquished by the federal government (Parsons 1995). Currently, the RPA owns most property adjacent to RANGB and holds a 70-year lease for the airfield; a 50-year lease for 29 acres adjacent to the airfield on the north side of Taxiway A used for aviation support; and a lease on three jet fuel storage tanks. The RPA manages and operates Rickenbacker International Airport on owned and leased land.
Land excessed to the RPA as a part of the September 1994 base realignment will be used as designated in the Reuse Plan. The Reuse Plan for RANGB includes re-designating most of the base's former properties for institutional (e.g., military reserve), commercial, or industrial purposes. Rickenbacker International Airport will occupy approximately 1,300 acres and use the main runway, taxiway, stub apron parking, operational apron, and aviation support. Other parcels are going to be transferred to OHANG, OARNG, and the Army Reserve, all of which currently occupy portions of the base. There are no plans to redevelop the current base area as residential property. If, in the future, land is sold for residential development, RANGB will enforce deed restrictions to protect public health (e.g., prohibition from drinking UWBZ groundwater, prohibition from drilling near groundwater plumes in order to prevent further migration of contaminants into underlying aquifers) (Friedstrom 2000). RANGB recently implemented similar provisions (including the prohibition of drawing on-site well water from the UWBZ and deed restrictions on on-site drilling at Sites 2, 21, 41, 42, and 43) to prevent potential future on-base exposures (Friedstrom 2000).
ATSDR conducted an initial site visit of RANGB in November 1994. The purpose of the visit was to collect information necessary to rank the site according to its potential public health hazard and to identify public health issues related to environmental contamination at the base. ATSDR staff met with RANGB staff and representatives from the Air Force, OEPA, Franklin County Water Department, and local citizens. ATSDR health assessors identified several community health concerns during the visit. As a result of these meetings, site visit observations, and a preliminary review of the data currently available, ATSDR identified four areas of concern: groundwater quality, landfill contamination, drainage ditch contamination, and the Reuse Plan (ATSDR 1995; US Air Force 1995).
In August 1995, the ATSDR Site Summary for Rickenbacker Air National Guard Base, Franklin and Pickaway Counties, Ohio, was released. This document preliminarily outlined issues identified during ATSDR's 1994 site visit to be evaluated by ATSDR during the public health assessment process.
In January 1999, ATSDR conducted a second site visit at RANGB. ATSDR viewed all on-base sites and remediation efforts, as well as those located in the off-base housing areas. ATSDR met with Air Force, USACE, USEPA, and OEPA representatives, and identified RANGB's fuel line distribution system and landfill as two sites of potential concern, primarily due to soil contamination and their potential to leak into underlying groundwater. ATSDR also identified groundwater supplying local production wells, surface water in local drainage ditches, and fish in Big Walnut Creek as potential exposure pathways at RANGB. Contacts were made with the community of Lockbourne to discuss community concerns.
ATSDR learned that during a RANGB Restoration Advisory Board (RAB) meeting in December 1998, community members expressed several concerns regarding:
Other than general questions regarding groundwater contamination and thyroid diseases, no local community members expressed any specific health concerns they attribute to RANGB. Most concerns appear to focus on the environmental quality and economic viability of the land areas to be turned over to the public under the base Reuse Plan.
Quality Assurance and Quality Control
In preparing this public health assessment, ATSDR relied on the information provided in the referenced documents. Documents prepared for the CERCLA and RCRA programs must meet specific standards for adequate quality assurance and control measures for chain-of-custody procedures, laboratory procedures, and data reporting. The validity of the analyses and conclusions drawn in this document are dependent upon the availability and reliability of the referenced information. The environmental data presented in this public health assessment are from Air National Guard, Air Force, USACE, and OEPA reports; the remedial site investigations of the IRP sites; quarterly groundwater monitoring data; and drinking and irrigation water data from RANGB, municipal, and private wells.Based on our evaluation, ATSDR determined that the quality of environmental data available in site-related documents is adequate to make public health decisions.
EVALUATION OF ENVIRONMENTAL CONTAMINATION AND POTENTIAL EXPOSURE PATHWAYS
In this section, exposure pathways are evaluated to determine whether people accessing or living near RANGB could have been (past scenario), are (current scenario), or will be (future scenario) exposed to site-related contaminants. In evaluating exposure pathways, ATSDR determines whether exposure to contaminated media has occurred, is occurring, or will occur through ingestion, dermal (skin) contact, or inhalation of contaminants. If the contamination is located in an area where exposure is not likely, no public health hazard will be expected to occur (for instance, where contaminated soil is located in an area that is fenced and access is restricted). Exposure to contaminants does not necessarily result in adverse health effects. For a health hazard to be possible, the contaminants must be present in large enough amounts to cause harm, and the exposure must be for a long enough time for the effect to be possible. To determine whether completed pathways pose a potential health hazard, ATSDR compares contaminant concentrations to health-based comparison values.
Comparison values are calculated from available scientific literature on exposure and health effects. These values, which are defined for each of the different media, reflect the estimated maximum contaminant concentration for a given chemical that is not likely to cause adverse health effects, given a standard daily ingestion rate and standard body weight. If contaminant concentrations are above comparison values or background concentrations, ATSDR further analyzes exposure variables (for example, duration and frequency) and the toxicology of the contaminant. This exposure evaluation process is summarized in Figure 3. To determine background concentrations, non-impacted on-base locations in the RANGB vicinity were selected and approved by the BCT comprised of Air Force, USEPA, and OEPA representatives. These selected locations were sampled and characterized by the Air Force. Investigation results on naturally occurring background metals in soil, groundwater, surface water, and sediment were used to compare results from samples collected at RANGB (IT Corp. 1998).
ATSDR evaluated available information on underlying groundwater, local surface water and sediment, the 44 IRP sites (Figure 4), and locally-caught fish to determine if they pose any past, current, or potential future public health hazards. After fully evaluating potential human exposure pathways at RANGB, ATSDR concluded that public exposures to groundwater, surface water, sediment, soil, and locally-caught fish are not likely to result in adverse human health effects because contamination in these media is below levels of health concern, there is no public exposure to contamination in these media, and/or interim and remedial activities will prevent potential future exposures. ATSDR identified no completed exposure pathways for any contaminants at levels that would pose a possible health concern, although surface soil exposure at Rickenbacker Landfill poses an indeterminate public health hazard because the nature and extent of contamination has not been fully characterized. Information on the various contaminated media and associated exposure pathways is summarized in Table 1 and the following text.
The following discussion evaluates community concerns about potential human exposure via contaminated groundwater, surface water and sediment, soil, and locally-caught fish. ATSDR's conclusions regarding the past, current, and potential future exposures to various environmental media on and in the vicinity of RANGB are based on an evaluation of information gathered from remedial site investigations, groundwater monitoring data, on- and off-base drinking water well data, irrigation well data, and the observations compiled during site visits.
Hydrogeology
Three water-bearing units have been identified at RANGB: the upper water-bearing zone (UWBZ), the intermediate aquifer, and the deep aquifer. Only the intermediate and deep aquifers are confined aquifers. The UWBZ is encountered beneath all portions of RANGB, typically with the top of the water table less than 10 feet below ground surface. Groundwater flow direction and gradient in the UWBZ appear to be controlled primarily by surface topography, including the configuration of the base drainage system and the locations of the creeks in the area. Some movement of groundwater and contaminants may occur along buried subsurface utilities. Many utilities at RANGB, however, are backfilled with native soil materials and are not bedded with uniform sand or gravel. In such cases as these, subsurface utilities may not form preferential groundwater flow paths (IT Corp. 1998). A north/south trending groundwater divide is located in the central portion of the base. Groundwater west of this divide flows southwest toward Big Walnut Creek. Groundwater east of the divide flows southeast toward Little Walnut Creek (Parsons 1995).
The intermediate aquifer is the shallowest water-bearing zone capable of supporting a water supply adequate for domestic use. It is present beneath the base at depths of between 60 and 100 feet below ground surface. The gradient of the intermediate aquifer is west and west-southwest.
The deep aquifer lies at depths of between 130 and 210 feet below ground surface, where it meets a shale bedrock layer. The gradient of the deep aquifer is west and west-southwest.
Groundwater Use
Five on-base wells (RB-1 through RB-5), when previously active, provided water to RANGB and the village of Lockbourne. The wells typically had water-producing zones that began around 30 to 90 feet below ground surface (historical records indicate that four of the five production wells drew from the deep aquifer--it is unknown which aquifer supplied the fifth well). Although no longer used, the five production wells are located in the northwest portion of the base. A sixth production well (RB-6), screened in the intermediate aquifer, supplied water to the base heating plant and was not used for human consumption. Because of base realignment, declining personnel, and the cost of maintaining the on-base well system, the base wells were shut down in 1993 (ATSDR 1995). The six formerly-used on-base water supply wells were abandoned and closed in accordance with OEPA regulations for water supply well closure. RANGB and the village of Lockbourne now receive potable water from the city of Columbus Municipal Water System which meets all federal and state drinking water standards. A seventh production well, which has no "RB" designation, is located adjacent to the former Rickenbacker clubhouse at the golf course. This well provided domestic water for past patrons of the golf course, prior to the early 1980s, after which it was temporarily shut down (Edwards 2000). In 1983, the golf course, including the seventh well, was sold by GSA to a private organization (US Air Force, 2000). Under new ownership, the well was re-activated in the late 1980s and continues to be used for drinking water purposes for golf course visitors. The well draws from the intermediate aquifer and meets all federal and state drinking water standards (Edwards 2000; ODHL 2000; ODHDL 1999; ODHDL 1997; ODNR 1953).
Private production wells still supply some off-base homeowners with drinking water. Private wells located north, south, and east of the base draw primarily from the intermediate aquifer. In 1996, seven residences in the village of Lockbourne were identified as having private production wells. Five of these wells draw water from the UWBZ; two draw water from the intermediate aquifer. One of these residences, however, was later determined to be on municipal water (Waters 1996). Most irrigation water comes from the intermediate aquifer.
Nature and Extent of Groundwater Contamination
Past activities and waste disposal practices at RANGB affected groundwater underlying military property. Dioxins, detected at trace levels, are contaminants of concern at the Rickenbacker Landfill and are currently being further investigated by the USACE. Volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), polycyclic aromatic hydrocarbons (PAHs), and metals (including arsenic and lead) have been detected above ATSDR comparison values at:
Groundwater contaminant plumes underlying RANGB have been detected in, and appear limited to, the UWBZ--with the exception of the Rickenbacker Landfill area, where groundwater contaminants have been detected in the UWBZ and intermediate aquifers. All on-base production wells, when active, were located upgradient from the groundwater contaminant plumes and/or drew from the deeper aquifer.
The groundwater contaminant plumes underlying the base flow primarily in a west or west-southwest direction, towards the village of Lockbourne. Groundwater monitoring indicates that contaminants are localized and not migrating off RANGB property (Friedstrom 2000). When Lockbourne private wells were sampled in 1985 as part of a construction loan application to tie the village into Columbus's water supply, bromochloromethane, other chlorinated methane compounds, and metals were detected below ATSDR drinking water comparison values. Lockbourne residents expressed concern that the source of the groundwater contamination was the Rickenbacker Landfill.
In 1986, OEPA, the Ohio Department of Health, and the Franklin County Health Department collected water from 22 Lockbourne private wells and four RANGB monitoring wells. Several of the Lockbourne private wells had high bacterial counts because of failed septic systems and poorly constructed wells (Franklin County District Board of Health 1986). Trace amounts of lead, arsenic, and cadmium were also detected in some private wells, all at levels below ATSDR comparison values and USEPA's Maximum Contaminant Levels (MCL) for drinking water (15, 50, and 5 parts per billion [ppb], respectively) (Franklin County District Board of Health 1986). The RANGB monitoring wells contained higher contaminant concentrations than those detected in Lockbourne private wells, with concentrations of lead and arsenic above ATSDR comparison values. Contaminants were limited to the UWBZ and intermediate aquifer.
After Lockbourne private wells were found to contain high bacterial counts and trace contaminants in 1986, RANGB trucked in potable water from base wells to the community. By July 1989, the entire village of Lockbourne was connected to the RANGB drinking water supply line (Ohio Department of Health 1989). In 1993, the base and the village of Lockbourne were connected to the city of Columbus Division of Water (Rickenbacker Port Authority 1993). Seven residences, however, continued to use private well water. In 1995, OEPA collected and analyzed groundwater samples (screened in the shallow aquifer) from five of these seven private wells. All sampled wells drew water from the UWBZ. OEPA deemed it unnecessary to sample two wells that drew water from the deeper intermediate aquifer because contaminant concentrations were believed to be below UWBZ levels. Water from the five tested wells met all federal and state drinking water standards (Waters 1996).
In 1997, USACE detected a variety of low-level dioxins in groundwater underlying the Rickenbacker Landfill. Because different dioxin compounds each have varying harmful effects, ATSDR uses a toxicity equivalent factor to assess the relative toxicity of each compound by comparing it to the dioxin 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD-2,3,7,8). TCDD-2,3,7,8 is one of the most toxic dioxins and has been studied more extensively than other dioxins. Thus, TCDD-2,3,7,8 serves as the prototype for dioxins, and the TCDD-2,3,7,8 equivalent concentration serves as a conservative screening value. Hereafter, this public health assessment refers to TCDD-2,3,7,8 equivalent concentrations as "dioxin" concentrations.
During the 1997 sampling event for dioxin, no groundwater samples exceeded ATSDR's most conservative comparison values (chronic Environmental Media Evaluation Guide of 0.01 ppb for a child and 0.04 ppb for an adult). The maximum detected dioxin concentration of 0.00004 ppb, however, slightly exceeded USEPA's MCL of 0.00003 ppb (PMC 1999). This sample was collected from the UWBZ in an on-base monitoring well near Rickenbacker Landfill. There was no public exposure to water from this well.
USACE conducted a subsequent phase of dioxin sampling in 1998 to further investigate and characterize dioxin contamination. Unfiltered and filtered groundwater samples were collected and analyzed at six selected locations near the Rickenbacker Landfill. All dioxin concentrations (maximum detected concentration of 0.000001 ppb) were below ATSDR's comparison values and USEPA's MCL. Sampling results indicate that the Rickenbacker Landfill does not appear to be contributing to groundwater dioxin concentrations. Rather, the dioxins appear ubiquitous in the environment and have been primarily attributed to suspended solids in the groundwater samples (HSDB 1999; PMC 1999).
OEPA periodically samples groundwater underlying the village of Lockbourne, including private well water, and has found it to meet federal and state drinking water standards. The existing wells in the monitoring network, however, do not allow for a determination of whether there is any connection between shallow groundwater contamination in the UWBZ at the Rickenbacker Landfill and the quality of groundwater underlying Lockbourne. USACE continues to investigate these potential connections.
Evaluation of Potential Public Health Hazards
On-base Exposures
In sampling during 1986, no contaminants were detected above USEPA's MCLs in six on-base wells (RB-1 through RB-6). Prior to 1986, active on-base wells (including the seventh well at the golf course) were tested for some water quality parameters, including hardness, corrosivity, bacterial counts, lead, and iron (US Air Force 2000; Edwards 2000; ODHL 2000; ODHDL 1999; ODHDL 1997; ODNR 1953). All active on-base production wells met federal and state drinking water standards in effect at the time. Water quality parameters for dioxins, VOCs, SVOCs, and PAHs, however, were not evaluated when the wells were active. Therefore, quantitative historical groundwater data are not available to estimate past exposure (if any) to these chemicals for the base and village of Lockbourne. Current groundwater data supports that the on-base production wells drew water from upgradient and/or uncontaminated aquifers (e.g., the deep aquifer). For these reasons, ATSDR does not believe that there was any public exposure to on-site contaminants. Currently, drinking water is provided by municipal water sources that are tested routinely to ensure they meet all federal and state drinking water standards. To prevent potential future exposures, RANGB recently implemented provisions, including the prohibition of drawing on-site well water from the UWBZ and deed restrictions on on-site drilling at Sites 2, 21, 41, 42, and 43 (Friedstrom 2000). ATSDR concludes that groundwater underlying the base poses no past, current, or future public health hazard.
Off-base Exposures
Currently, there is no known off-site groundwater contamination that exceeds ATSDR comparison values or presents a public health hazard. Remedial actions at Sites 2, 21, 41, 42, and 43 will prevent contaminants from leaching into groundwater and migrating off site in the future. Sites 1, 2, and 12 are the only other IRP sites with the potential for future migration of contaminants to off-site areas. RANGB and OEPA are currently discussing potential remedial actions at Sites 1 and 12 to ensure that future exposures will be prevented. At Site 2, RANGB is preventing potential future exposures by installing a reactive wall to remediate groundwater contaminants.
The potential for exposure to dioxin-contaminated groundwater near Rickenbacker Landfill appears minimal because the use of private wells in the area is very limited (PMC 1999). Additionally, household private water supply systems usually include a pressure tank and filtration system which would decrease the amount of suspended solids in the water. It is expected that these measures would decrease the concentration of dioxin in the water ingested to below method detection limits and well below levels that would present a health hazard (PMC 1999).
Records for well water analyses in the village of Lockbourne indicate that there was no substantial contamination of groundwater from 1986 to the present and that contaminant concentrations were not likely higher historically than they are at present. No one is exposed to harmful levels of contaminants because contaminant plumes have not impacted private drinking water wells or irrigation wells in the village of Lockbourne and other surrounding areas. Moreover, most local residents receive water from the Columbus Municipal Water System which meets all federal and state drinking water standards (e.g., MCLs). ATSDR concludes that off-site groundwater poses no apparent public health hazard.
On-site Surface Water and Sediment Characteristics
The terrain at RANGB is flat and most of the soils are poorly drained. A topographic high extends across RANGB from the northwest to the center of the flight line and forms a hydrogeologic divide for surface water runoff. Surface water on the east side of the divide drains into Little Walnut Creek. Surface water on the west side of the divide drains into Big Walnut Creek. Little and Big Walnut Creeks flow from north to south. The Ohio Canal, which runs along Canal Road and the western boundary of the base, is typically dry (ANGRC 1992). The village of Lockbourne lies within a 100-year floodplain and Big Walnut Creek floods periodically (Federal Emergency Management Agency 1979).
During initial base construction, the Air Force created a base-wide drainage ditch system to divert the surface runoff and rinse water from base operations to nearby waterways. In 1954, the village of Lockbourne entered into a formal agreement with the federal government to allow the USACE to construct this drainage ditch through the village and drain RANGB wastewater (surface runoff and rinse water) into Big Walnut Creek (Village of Lockbourne 1994). RANGB currently holds National Pollutant Discharge Elimination System permits with the state to discharge wastewater into the ditch system.
All surface water runoff from RANGB is drained through this extensive storm drainage network of corrugated metal pipes, concrete pipes, and open drainage ditches. The base drainage network has been designated as Site 25 (formerly Sites 25 and 27), and includes off-base surface water drainages that have been impacted by releases from the base. The on-base drainage system consists of several ditches of varying widths and depths that encircle the installation and discharge RANGB runoff, either to the east into the Little Walnut Creek or the west into Big Walnut Creek (Figure 1) (U.S. Air Force 1994). To the west, the ditch passes by several homes before it reaches the Ohio Canal, passes through the Lockbourne Municipal Park, and ultimately drains into Big Walnut Creek. Excavation by unknown persons has altered the ditch flow in recent years (ATSDR 1995). To the east, the ditch flows along several local roads, next to a trailer park, and past some other residences as it flows into Little Walnut Creek.
Site 25 includes approximately 8.5 miles of drainage ditches and encompasses four major drainage areas, each of which flows to one of four emergency interceptors. The four major drainage areas of Site 25 are referred to as the Northeast, Southeast, Southwest, and Northwest Quadrants. Each of these quadrants is discussed in greater detail in Appendix A. Surface water running through the emergency interceptors ultimately flows into either Little or Big Walnut Creeks. A fifth drainage area encompasses the Ordnance Storage Area in the south-central portion of the base and drains directly into Little Walnut Creek.
The base drainage system between the runways consists of a series of long, broad, grass-covered swales, approximately 7 to 8 feet deep. Surface water runoff in the swales flows into storm drains located at the ends. Discharge from the storm drain culverts flows into the ditch system. The flightline swales are dry during periods of no precipitation. Flow rates through the on-base drainage ditches vary and at times no standing water is present (Parsons 1995).
Nature and Extent of Surface Water and Sediment Contamination
Most of the contamination in the drainage ditches occurs in the sediment and not in the surface water. Low-level dioxins were detected in one sediment location in one drainage ditch, but at a level below ATSDR comparison values for soil (PMC 1999). On-site sediment contaminants that exceeded ATSDR comparison values include VOCs, SVOCs, PAHs, pesticides, and metals. All contaminant concentrations were greatest in the most upgradient portions of the ditch system, areas where there is no public access. The primary mode of contaminant migration in the ditches appears to be transport of contaminated sediment. Contaminant concentrations generally decreased below ATSDR comparison values as the ditches flowed off base and into publicly accessible areas.
Contaminants detected in each of the four quadrants of the ditch system were similar (IT Corp. 1998). Contaminants of primary concern were PAHs and those identified with the potential for off-base migration, specifically pesticides and mercury in sediment.
Levels of total PAHs in the most upgradient portions of the ditch system sediments reached up to 100 parts per million (ppm), but the concentration gradient declined as ditches ran off base and into Little Walnut Creek and Big Walnut Creek (IT Corp. 1998). The elevated concentrations of PAHs and pesticides in the vicinity of the emergency interceptors is apparently due to sediment deposition in those areas. Off base, in Big Walnut Creek, PAH concentrations were detected below 10 ppm (OEPA 1998). Typical background concentrations for PAHs range from less than 2 ppm in agricultural soil to over 500 ppm in urban soil (ATSDR 1994a).
On-base pesticide concentrations in RANGB sediments reached a maximum detected concentration of 2 ppm for 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) and a maximum detected concentration of 0.4 ppm for 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT). These maximum detected concentrations are below ATSDR's comparison values of 3 ppm and 2 ppm for DDD and DDT, respectively. Concentrations of DDD in Big Walnut Creek sediment were detected at 8 ppb (OEPA 1998). DDT was not detected in Big Walnut Creek sediment. Typical background concentrations for DDD and DDT in agricultural soils range between 0.2 to 6 ppm (ATSDR 1994b).
Mercury concentrations in RANGB sediment ranged from 0.03 to 0.4 ppm. Off base, in Big Walnut Creek, mercury concentrations reached 0.05 ppm. In industrial use scenarios, mercury concentrations up to 400 ppm in soil and sediment are believed protective of human health and the environment (IT Corp. 1998). RANGB levels are several orders of magnitude below this level. ATSDR does not have soil comparison values for mercury, but comparison values for a similar compound, mercuric chloride, are available. Detected mercury concentrations at RANGB are several orders of magnitude below ATSDR's mercuric chloride comparison values for soil (100 ppm for children and 1,000 ppm for adults).
Given the industrial/commercial land use of the area and the agricultural land use in the surrounding vicinity, all sediment contaminant concentrations in the RANGB drainage ditch system may be within normal background concentrations. Currently, the BCT and their technical support members (including representatives from the Air Force, USEPA, and OEPA) are discussing the status of the drainage ditch system under the IRP. The Air Force recommends NFA status, but USEPA and OEPA recommend that the Air Force conduct toxicity testing, a feasibility study, or a "hot spot removal" of the more highly contaminated sediments in the ditch system.
Evaluation of Potential Public Health Hazards
Local surface waters are not used for drinking water so there is minimal, if any, public exposure to this water. Any incidental, infrequent exposure to this water will not result in adverse health impacts.
All off-site sediment contaminant concentrations are within normal background ranges, but some on-base sediment contaminant concentrations exceeded ATSDR comparison values. Public access and exposure to these on-base sediments, especially where contamination is greatest, is minimized by industrial/commercial land use surrounding the drainage ditches. The likelihood that workers in their routine responsibilities, or trespassers during their infrequent access, would contact the most contaminated sediments for an extended period is remote. If workers or trespassers do contact contaminated sediments, exposure most likely is intermittent and brief. Such incidental, infrequent exposure to sediment via dermal and/or ingestion contact is not likely to result in adverse health impacts. ATSDR concludes that past, current, or future exposure by the public to local surface waters and sediment poses no apparent public health hazard.
Nature and Extent of Soil Contamination
Numerous investigations have been conducted since 1986 to characterize RANGB soil contamination. The completion of the site FS found that four(2) IRP sites at RANGB require soil removal activities. These sites contain the following contamination above ATSDR comparison values:
Soil removal activities at these four sites are intended to minimize the leaching of contaminants into the groundwater and prevent additional groundwater contamination in the future. Air Force and OEPA discussions are ongoing regarding potential soil remediation requirements at Site 1 (Former Hazardous Waste Storage Area) and Site 12 ( Bulk Storage Tank Farm) to remove VOCs and SVOCs.
Surface soil contamination also exists in the Rickenbacker Landfill, a FUDS site undergoing investigation by USACE. Although site contaminants have not been fully characterized, dioxins, metals, and VOCs have been detected in surface soil at Rickenbacker Landfill, all at concentrations below ATSDR comparison values for soil. In the past, contaminated water treatment plant lime sludge was disposed of at the landfill (Bynum 1992). Sampling of the sludge at the water treatment plant indicated contamination with several metals. In 1986, the Ohio Department of Health detected trichloroethylene (TCE) at 1.4 ppb in a landfill leachate sample (Bynum 1992). The TCE level was below the USEPA's MCL (5 ppb) for drinking water and was not of health concern. The leachate sample, however, may not be representative of the composition of the leachate generated in the landfill because the sampling took place under dry conditions. No significant rain fall had occurred for more than 2 weeks prior to the sampling. According to OEPA, four previously observed leachate seeps along the western edge of the landfill were reduced to a trickle (OEPA 1986). During a 1991 site inspection, OEPA observed additional leachate seeps along the southwestern perimeter of the landfill. According to OEPA, soil gases were also detected at the Rickenbacker Landfill (ATSDR 1995). USACE is beginning its investigation of the landfill, with preliminary SI information expected in May 2000 (Learner 2000).
Evaluation of Potential Public Health Hazards
Potential receptors for on-site soil contaminants include the on-base industrial workers (adult) and on-base trespassers (adult and child). An evaluation of potential public health hazards associated with soil contamination at all 44 IRP sites is summarized in Appendix A. No IRP sites are associated with any known public health hazards because: 1) no site-related contaminants are present where exposure to the public could occur; 2) contaminant concentrations detected are too low to pose a health hazard; and/or 3) past and current exposures to the general public have been prevented. For the sites requiring soil remediation, remedial activities have or will reduce contaminant concentrations to levels that pose no public health threat. In other locations, contamination occurs below ground surface in subsurface soils and public exposure is not possible. Most IRP sites (including the five remediation sites) lie in industrial/commercial areas that are infrequently, if ever, contacted by the public. It is not likely that workers in their routine responsibilities contact the most contaminated soil for an extended period of time. If workers do contact contaminated soil, exposure most likely is intermittent and brief. Such minimal, infrequent exposure to on-site contaminants, if it occurs at all, would not be expected to result in adverse health impacts (see Appendix A). ATSDR concludes that on-site soils at the 44 IRP sites pose no apparent public health hazards.
At Rickenbacker Landfill, the principal exposure concern is that of short-term, infrequent exposure by trespassers, primarily via incidental dermal contact with soil. Only a 3-foot tall fence that is easily crossed surrounds the landfill. No signs are currently posted at the site to prohibit access (Green 2000). The USACE, RANGB, and regulators report that trespassers, including children and hunters, do periodically access the site.
Environmental contamination at Rickenbacker Landfill is still under investigation. The limited sample analyses available at present does not indicate sufficient contamination is present to pose a public health hazard as a result of infrequent and intermittent exposure. However, until sufficient data are available to confirm that contaminants are not present at levels of health concern to trespassers, the USACE should ensure that adequate fencing limits access and that signs are posted to apprise trespassers of the potentially hazardous nature of the site. Additionally, as a part of the ongoing public involvement activities at RANGB, the public should be provided with information detailing the extent of the contamination present and the status of the remedial investigations. ATSDR concludes that because information is currently limited on-site soil at Rickenbacker Landfill poses an indeterminate public health hazard.
Nature and Extent of Contamination
According to citizens of Lockbourne, people fish in Big Walnut Creek for recreational purposes (ATSDR 1995). In 1991, OEPA sampled one area of Big Walnut Creek as part of a larger stream survey. The 1991 sampling event revealed that local fish populations fully met OEPA's exceptional warmwater habitat (EWH) criteria, based on fish abundance, diversity, and health. Fish tissues were not quantitatively tested or analyzed for potential contaminant concentrations.
In 1996, OEPA conducted a biological and water quality study of Big Walnut Creek and Walnut Creeks tributaries that found a decline in the fish community compared to 1991. The 1996 study sampled a total of 795 fish, representing 40 species and two hybrids, from Big Walnut Creek. The decline in the fish community (as evidenced by a decrease in the number of species detected) resulted in OEPA designating Big Walnut Creek as meeting partial achievement of the EWH criteria. The evaluation of Big Walnut Creek immediately upstream, adjacent to, and downstream from the Rickenbacker Airport storm water outlet found that these waters were of "good to very good" conditions (OEPA 1998). OEPA concluded that the Rickenbacker Airport "did not appear to have a negative influence on the fish communities of Big Walnut Creek" (OEPA 1998). OEPA did not analyze the fish tissues for potential contaminant concentrations.
The Walnut Creek tributaries evaluated, including a man-made channel 0.5 miles long, contained fish populations deemed "fair, marginally good, good, very good, and very good/exceptional" by OEPA's EWH criteria (OEPA 1998). Because it is unlikely that these tributaries contain enough fish to be an appreciable source for consumption, they were not considered to contain fish population deemed of concern for human health. For this reason, OEPA did not sample tissue samples from these populations for potential contaminant concentrations. It is not known if local residents fish from these tributaries, but it appears that most local fishing is limited to Big Walnut Creek and other large surface water bodies.
Evaluation of Potential Public Health Hazards
Based on EWH criteria, as well as the low levels of contaminants detected in water and sediment samples, it is unlikely that contamination has negatively affected fish populations. As described in previous sections of this document, the water and sediment quality of Big Walnut Creek and other local fishing waters are within normal background ranges. ATSDR does not expect these low-levels of ubiquitous environmental contaminants to bioaccumulate in fish tissue at levels of concern to public health. No public health data or community health problems were identified to indicate that local fish are unsafe for human consumption. ATSDR will assess any new data (e.g., tissue analysis studies), if and when new data become available, and will then, if necessary, reevaluate its conclusion of potential public health hazards. Based on current, available information, however, ATSDR concludes that the consumption of local fish poses no apparent public health hazard.
By talking with local citizens and reviewing the discussions during the RANGB RAB Meeting in December 1998, ATSDR identified several community health concerns. Specifically, ATSDR found that the community had concerns regarding groundwater contamination, the proposed plan for the five IRP remediation sites, the status of the USACE project at the Rickenbacker Landfill, and the status of other USACE projects on adjacent property formerly owned by the Air Force. No public health hazards are associated with the 44 IRP sites. ATSDR did not identify any public health hazards at Rickenbacker Landfill, but until USACE environmental investigations are completed, ATSDR recommends taking precautionary measures (e.g., enhance fencing, post signs) to deter trespassing. The status of the various sites and remediation projects are outlined in the Public Health Action Plan section and Appendix A of this report.
A past community health concern involved the question of whether or not increased incidences of thyroid cancer might be occurring in the community due to environmental contamination from RANGB. In response to this concern, in 1986, the Ohio Department of Health conducted a cancer incidence study to determine if Lockbourne cancer incidence rates were elevated due to possible exposure to contaminants in drinking water. Elevated cancer rates were not found (Ohio Department of Health 1986). Based on toxicological information and the nature of environmental contaminants on and in the vicinity of RANGB, it does not appear that site-related contaminants could be causally related to thyroid cancer. Moreover, there is only limited exposure, if any, to the environmental contaminants at RANGB. Adverse public health impacts are not likely from the exposures that would reasonably be expected to occur or would have reasonably been expected to have occurred in the past. Based on recent information obtained from the base environmental program, from regulators, and from the Lockbourne community, the concern regarding thyroid disease is general and no longer involves contamination from RANGB.
During the public comment period, ATSDR identified two additional concerns: (1) the drainage ditches (Site 25, formerly Sites 25 and 27), and (2) future land use scenarios. As detailed in the Evaluation of Environmental Contamination and Potential Exposure Pathways section and in Appendix A, public exposure to on-site sediments is minimal, if exposure occurs at all. Without an exposure pathway, no public health hazards exist. Therefore, based on the current industrial/commercial land use at RANGB, Site 25 poses no apparent public health hazards. As for future land use scenarios, the RPA will continue to maintain the property for industrial/commercial use. There are no plans to redevelop the area as residential property. If, however, in the future the property is sold for residential development, RANGB will enforce deed restrictions to protect public health (e.g., prohibition from drinking UWBZ groundwater, prohibition from drilling near groundwater plumes to prevent the migration of contaminants into underlying aquifers) (Friedstrom 2000).
ATSDR recognizes that infants and children may be more sensitive to exposures than adults in communities with contamination in their water, soil, air, or food. This sensitivity is a result of a number of factors. Children are more likely to be exposed to soil or surface water contamination because they play outdoors and often bring food into contaminated areas. For example, children may come into contact with and ingest soil particles at higher rates than adults do; also, some children with a behavior trait known as "pica" are more likely than others to ingest soil and other nonfood items. Children are shorter than adults, which means they can breath dust, soil, and any vapors close to the ground. Also, they are smaller, resulting in higher doses of chemical exposure per body weight. The developing body systems of children can sustain permanent damage if toxic exposures occur during critical growth stages. Because children depend completely on adults for risk identification and management decisions, ATSDR is committed to evaluating their special interest at sites such as RANGB, as part of the ATSDR Child Health Initiative.
ATSDR has attempted to identify populations of children in the vicinity of RANGB and any completed exposure pathways to these children. According to the 1990 U.S. Census, 25 percent of the persons in Lockbourne are children under the age of 19 years old, and 29 percent of the persons in Groveport are children under the age of 19 years old. The closest schools to RANGB are associated with the Lockbourne, Groveport, and Hamilton Meadows subdivisions, and the adjoining subdivision immediately north of the base. No children live on base, but children have been seen on RANGB riding their bicycles. Teenagers have also been seen on base in cars (OEPA 2000).
Off-base child exposures to local drinking water and surface water will not result in adverse health impacts because contaminant concentrations at all off-base exposure points (i.e., the five private production wells drawing from the UWBZ) are below ATSDR comparison values for children. For most on-base contaminants, including the 44 IRP sites, there is little, if any, child exposure because children do not regularly access RANGB. Such short-term and infrequent contact to on-base media is not expected to result in contaminant exposures of potential public health concern. Children trespassing on RANGB, however, may incidentally be exposed to on-base contaminants at Rickenbacker Landfill. Except for minimal fencing (approximately 3 feet tall), no measures currently prevent unauthorized access to the landfill (Green 2000). Because the nature and extent of contamination at Rickenbacker Landfill has not yet been fully characterized, the landfill poses an indeterminate health hazard to child trespassers. ATSDR concludes that past, current, and future exposures to on- and off-site groundwater, surface water, sediment and soil at the 44 IRP sites pose no apparent public health hazard for children. Rickenbacker Landfill poses an indeterminate public health hazard for children.
Based on a thorough evaluation of available information, ATSDR has reached the following conclusions:
The Public Health Action Plan (PHAP) for RANGB contains a description of actions taken and those to be taken, as necessary, by ATSDR, the Air Force, OHANG, OARNG, USEPA, OEPA, and USACE at and in the vicinity of the base subsequent to the completion of this public health assessment. The purpose of the PHAP is to ensure that the public health assessment not only identifies public health hazards, but provides a plan of action designed to mitigate and prevent adverse human health effects resulting from exposure to hazardous substances in the environment. The public health actions that are completed, being implemented, or planned are as follows (see Figure 5):
ANGRC. 1992. U.S. Air National Guard Readiness Center. Environmental Assessment of Three Currently Proposed Actions at Rickenbacker Air National Guard Base, Ohio. Andrews AFB, Washington, D.C.
ATSDR. 1994a. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Polycyclic Aromatic Hydrocarbons. U.S. Department of Health and Human Services, Atlanta, Georgia.
ATSDR. 1994b. Agency for Toxic Substances and Disease Registry. Toxicological Profile for DDT, DDD, and DDE. U.S. Department of Health and Human Services, Atlanta, Georgia.
ATSDR. 1995. Agency for Toxic Substances and Disease Registry. Division of Health Assessment and Consultation. Rickenbacker Air National Guard Base Site Summary, Franklin and Pickaway Counties, Ohio. August 1995.
Bynum, DL 1992. Preliminary Assessment Narrative for the Rickenbacker Landfill. Ohio Environmental Protection Agency. January 1992.
Edwards.2000. ATSDR record of communication. Telephone conversation between David Edwards, former water plant foreman at Rickenbacker Air Force Base and Eastern Research Group, Inc., regarding the seventh on-site well. March 29, 2000.
ES.1994. Engineering Science. Environmental Baseline Survey. 1994.
Federal Emergency Management Agency. 1979. Flood Insurance Study for village of Lockbourne, Ohio, Franklin County. November 1979.
Franklin County District Board of Health. 1986. Letter to village of Lockbourne, from Joseph P. Weaver. September 12, 1986.
Friedstrom. 1999. ATSDR record of communication. Telephone conversation between Alan C. Friedstrom, BRAC Environmental Coordinator at Rickenbacker Air Force Base Conversion Agency and Eastern Research Group, Inc., regarding on-base worker and residential populations. May 10, 1999.
Friedstrom. 2000. ATSDR record of communication. Telephone conversation between Alan C. Friedstrom, BRAC Environmental Coordinator at Rickenbacker Air Force Base Conversion Agency and Eastern Research Group, Inc., regarding site up-dates. March 27, 2000.
Green. 2000. ATSDR record of communication. Telephone conversation between Walter Green, United States Army Corps of Engineers and Eastern Research Group, Inc., regarding Rickenbacker Landfill environmental investigation up-dates. March 27, 2000.
HMTC. 1987. Hazardous Material Technical Center. Installation Restoration Program Phase I - Record Search for Rickenbacker Air National Guard Base, Ohio. June 1987.
HSDB. 1999. National Library of Medicine, Hazardous Substances Database (as cited in PMC 1999).
IT Corp. 1996a. IT Corporation. Phase II Remedial Investigation/Feasibility Study Work Plan for Rickenbacker Air National Guard Base, Ohio.
IT Corp. 1996b. IT Corporation. Supplemental Phase II Environmental Baseline Survey Investigation for Rickenbacker Air National Guard Base, Ohio.
IT Corp. 1998. IT Corporation. Scientific/Management Decision Point IRP Site 25, Rickenbacker Air National Guard Base, Ohio. September 14, 1998.
Learner. 2000. ATSDR record of communication. Telephone conversation between Thomas Learner, United States Army Corps of Engineers and Eastern Research Group, Inc., regarding Rickenbacker Landfill environmental investigation up-dates. March 27, 2000.
McCarren. 2000. E-mail from Paul McCarren, IT Corp., to Eastern Research Group, Inc., regarding the current status of Site 1.
ODHDL. 1997. Ohio Department of Health Division of Laboratories, Columbus, Ohio. Inorganic Chemical Sample Submission Report for Rickenbacker Golf Club. September 11, 1997.
ODHDL. 1999. Ohio Department of Health Division of Laboratories, Columbus, Ohio. Inorganic Chemical Sample Submission Report for Rickenbacker Golf Club. November 3, 1999.
ODHL. 2000. Ohio Department of Health Laboratory, Columbus, Ohio. Inorganic Chemical Sample Submission Report for Rickenbacker Golf Club. March 13, 2000.
ODNR. 1953. State of Ohio Department of Natural Resources, Division of Water, Columbus, Ohio. Well log and drilling report. No. 101798. November 9, 1953.
OEPA. 1986. Ohio Environmental Protection Agency. Memorandum to Col. Richard Haines, from William M. Schneider. April 23, 1986.
OEPA. 1998. Biological and Water Quality Study of Lower Big Walnut Creek and Walnut Creek Tributaries. Rickenbacker Airport: Franklin and Pickaway Counties, Ohio. April 3, 1998.
OEPA. 2000. Letter to Max M. Howie, Jr., ATSDR, from Diana L. Bynum, Site Coordinator, Division of Emergency and Remedial Response, State of Ohio Environmental Protection Agency. Public Comments re: Rickenbacker ANGB, Franklin County, Ohio EPA #125-0685 Health Assessment. January 18, 2000.
Ohio Department of Health. 1986. Assessment of Cancer Incidence in the village of Lockbourne, Franklin County, Ohio.
Ohio Department of Health. 1989. Letter to ATSDR regarding groundwater use in Lockbourne, Franklin County, Ohio.
Parsons. 1995. Parsons Engineering Science Inc. Draft Final Remedial Investigation Report, Phase I, Sections 1, 2, 3, 4, and 5 and Appendices A-M. Rickenbacker Air National Guard Base. June 1995.
PMC. 1999. Program Management Company. Draft Report for the Supplemental Dioxin Investigation (Phase II Site Investigation) at the Former Lockbourne Air Force Base Landfill. March 1999.
Rickenbacker Port Authority. 1993. Letter to Larry Reed, USEPA from Lawrence D. Garrison. November 23, 1993.
SAIC. 1993. (Phase 1) Environmental Baseline Survey Rickenbacker Air National Guard Base Air Force Center for Environmental Excellence, Brooks AFB, Texas.
US Air Force. 1994. Memorandum for ATSDR, Attn: Joan Davis, ATSDR from Alan Friedstrom, RANGB. October 1994.
US Air Force. 1995. Memorandum Rickenbacker Restoration Advisory Board. Minutes of the March 21, 1995, Meeting. April 1995.
US Air Force. 2000. Comments on Public Comment PHA for Rickenbacker ANGB. Supplied to ATSDR, February 2000.
Village of Lockbourne. 1994. Letter to United States of America from Dwight E. Scott, Mayor village of Lockbourne. August 8, 1994.
Waters, T. W. 1996. Letter from Thomas W. Waters, Chief of the Environmental Restoration Division of the Corps of Engineers (Nashville District) to Sandra Isaacs of ATSDR regarding the testing of wells in the Village of Lockbourne, Ohio. December 20, 1996.
Table 2. Exposure Pathways at Rickenbacker Air National Guard Base
| PATHWAY NAME | POTENTIAL SOURCE OF CONTAMINATION | ENVIRON-MENTAL MEDIUM | POINT OF EXPOSURE | ROUTE OF EXPOSURE | TIME OF EXPOSURE | EXPOSED POPULATION | COMMENTS |
| Groundwater (on-base) |
Dioxins, volatile organic compounds (VOCs), semi-volatile
organic compounds (SVOCs), polycyclic aromatic hydrocarbons (PAHs), and
metals--underlying Rickenbacker Air National Guard Base (RANGB), primarily
in the upper water-bearing zone (UWBZ).
Sites that are likely contributing to the on-base groundwater contamination include: the Bulk Storage Tank Farm, the Rickenbacker Landfill, the Water Treatment Plant, the Oil/Water Separator at Building 848, a Jet Engine Test Stand, and a Test Cell Hush House. |
Groundwater (primarily limited to the UWBZ) |
• Prior to 1993, on-base employees and residents
obtained their drinking water from on-base production wells that drew underlying
groundwater, primarily from the deep aquifer.
• Post 1993, on-base employees and residents received their drinking water from the Columbus Municipal Water System which meets all federal and state drinking water standards (e.g., U.S. Environmental Protection Agency's Maximum Contaminant Levels [MCL]). |
Ingestion
(inhalation, dermal contact) |
Past: • No exposures occurred. According to 1986 sampling results, no contaminants were detected above their respective MCLs in on-base active production wells. Current and Future: |
Past: • None Current and Future: |
Past: • The primary production wells for the base appear to have been unaffected by contamination. Prior to 1993, the active wells extracted water from the deep aquifer and/or upgradient from contamination areas. Groundwater contamination underlying RANGB is limited primarily to the UWBZ. Sampled in 1986, the on-base wells met federal and state drinking water standards (e.g., MCLs). Current and Future: Past, current, and future use of RANGB groundwater poses no public health hazards. |
| Groundwater (off-base) |
Chlorinated methane compounds, lead, arsenic, and cadmium--
primarily in the UWBZ.
Rickenbacker Landfill may contribute to off-base groundwater contamination. The landfill contains leachate and surface soil contaminants above Agency for Toxic Substances and Disease Registry (ATSDR) comparison values and MCLs. Other RANGB sites that may contribute to the off-base groundwater contamination include: the Bulk Storage Tank Farm, the Water Treatment Plant, the Oil/Water Separator at Building 848, a Jet Engine Test Stand, and a Test Cell Hush House. |
Groundwater (primarily limited to the UWBZ) |
Water supplied to seven off-base households via private wells. These households have continued to use groundwater as a source of drinking water even though municipal water has been available to them since 1993. | Ingestion
(inhalation, dermal contact) |
Past and Current: • Contaminants were first detected in trace amounts in off-base wells in 1985. Low levels of chlorinated methane compounds and metals were detected below MCLs. Several private wells had high bacterial counts. Future: |
Past and Current: • None. Future: |
Past and Current: • Trace amounts of contaminants were detected in off-base drinking water at levels below concentrations of health concern. After contaminants were first detected, RANGB trucked in potable water from base wells to the community. These community wells were directly downgradient from on-base monitoring wells with contaminant concentrations above ATSDR comparison values and MCLs. In July 1989, the village of Lockbourne was connected to the Rickenbacker drinking water supply line. In 1993, local residents were connected to the Columbus Municipal Water System which meets all federal and state drinking water standards (e.g., USEPA's MCLs). • Even though municipal water was made available in 1993, seven off-base households continued to use their private wells as a source of drinking water. • Current private well monitoring data are unavailable for the seven active off-base private wells. Authorities have suggested that, as a precaution, local residents use only municipal water for domestic water supply. Future: • To prevent potential future exposures, the Air Force is remediating groundwater at Site 2; removing contaminated soil at Sites 21, 41, 42, and 43; and assessing the potential need for remedial actions at Sites 1 and 12. Past, current, and future exposures to off-base groundwater poses no apparent public health hazards. |
| Surface Water
and Sediments (on- and off-base) |
Dioxins, VOCs, SVOCs, PAHs, pesticides, PCBs, and metals from the RANGB storm drainage network area (Site 25). | Surface water and sediments | Off-base exposure to surface water and sediments | Dermal contact, incidental ingestion | Past, Current and Future: • No contaminants have been detected above MCLs in local surface waters. • Contaminants in sediments are most concentrated on base in areas inaccessible to the public. Except for DDD concentrations of 8 ppb in Big Walnut Creek, off-base sediment contaminants are below ATSDR comparison values for soil. All contaminant concentrations are within normal background ranges. |
• Past, Current and Future: Local residents |
Past, Current and Future: • Most of the contamination in RANGB drainage ditches occurs in the sediment and not in the surface water. There is minimal, if any, public exposure to these sediments. • No one drinks local surface waters so there is no public exposure to this water. • Incidental exposure to sediment is not likely to present a public health hazard. • For sediment in on-base ditches, the Air Force recommends no further action status. The regulatory agencies recommend conducting toxicity testing, a feasibility study, or "hot spot removal" actions. Past, current, and future exposures to on- and off-base surface water pose no public health hazard; sediments pose no apparent public health hazards. |
| Soil (on-base) |
RANGB sites with soil contaminants above ATSDR comparison
values include: the Bulk Storage Tank Farm, the Rickenbacker Landfill, the
Water Treatment Plant, the Oil/Water Separator at Building 848, a Jet Engine
Test Stand, and a Test Cell Hush House. VOCs, SVOCs, vinyl chloride, PAHs,
and metals have been detected.
The Rickenbacker Landfill contains leachate and surface soil contaminants above ATSDR comparison values. |
Soil | On-site soil (primarily at the Rickenbacker Landfill) | Dermal contact | Past, Current, and Future: • Incidental exposure of unknown duration. |
Past, Current, and Future: • On-site workers and trespassers. |
Past, Current, and Future: • Exposure to the 44 IRP sites is minimal, if it occurs at all. • Rickenbacker Landfill is surrounded by limited fencing and trespassers can access the site. • Fully-characterized soil contamination data are currently not available for Rickenbacker Landfill. ATSDR recommends that the Port Authority maintain the fence and post signs to deter area residents from trespassing. • Incidental exposure is not likely to present a public health hazard. Past, current, and future contact with on-site soil poses no apparent public health hazards. Rickenbacker Landfill poses an indeterminate public health hazard. |
| Consumption of Local Fish (Off-base in Little and Big Walnut Creeks) |
RANGB drainage system (Site 25, formerly Sites 25 and 27). | Local fish populations | Consumption of locally-caught fish | Ingestion | Past, Current and Future: • Unknown |
Past, Current and Future: • Local fishermen |
Past, Current and Future: • Although local fish populations may be declining, ATSDR found no public health data or community health problems to indicate that local fish are unsafe for human consumption. • ATSDR will assess any new data if and when they become available and reevaluate its conclusion of potential public health hazards. Past, current, and future consumption of locally-caught fish poses no apparent public health hazards. |
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