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PUBLIC HEALTH ASSESSMENT ADDENDUM

LETTERKENNY ARMY DEPOT
USA LETTERKENNY SOUTHEAST AREA
CHAMBERSBURG, FRANKLIN COUNTY, PENNSYLVANIA
AND
USA LETTERKENNY - PROPERTY DISPOSAL OFFICE AREA
CHAMBERSBURG, FRANKLIN COUNTY, PENNSYLVANIA


SUMMARY

The Letterkenny Army Depot (Letterkenny) is five miles north of Chambersburg, in Franklin County, Pennsylvania. The U.S. Army Depot consists of two National Priorities List (NPL) sites: USA Letterkenny Southeast Area (hereafter referred to as the SE Area) and USA Letterkenny - Property Disposal Office Area (hereafter referred to as the PDO Area). A public health assessment of those combined sites was released by the Agency for Toxic Substances and Disease Registry on September 30, 1988 (Appendix 1). The previous public health assessment combined discussion of both NPL sites due to similar contaminants and pathways. Since the release of the previous public health assessment, new environmental, community health concerns, and health outcome data have become available, warranting this addendum.

Seventeen contaminants have been detected on both NPL sites at concentrations exceeding ATSDR comparison values. Those contaminants were detected in on-site soils, groundwater, and surface waters. The sources of those contaminants are from past storage, treatment, and disposal practices at Letterkenny. The contaminants with the highest concentrations are volatile organic compounds (VOCs; e.g., trichloroethene, a solvent, and its associated degradation product, dichloroethene) which were used to maintain vehicles.

ATSDR considers the SE and PDO Areas to be Indeterminate Public Health Hazards because there are data gaps in environmental sampling on and off site and in site-specific health outcome data. Additional environmental and biota studies, as well as resampling of some private wells, are planned for 1993.

A past completed exposure pathway occurred via migration of VOC-contaminated groundwater to off-site residential wells east of the SE Area. Previous exposure occurred to residents using 41 off-site wells used for drinking water and other household purposes. Exposures were stopped when persons with well water containing VOCs at concentrations exceeding EPA drinking water standards were supplied bottled water in 1982. By 1987, those residences were connected to municipal water. Those past exposures are discussed in the Public Health Implications section of this document. Because the environmental data are limited, neither the range of concentrations of contaminants nor the duration of human exposure is known.

Some of those contaminated private wells and/or springs (particularly Rowe Run Spring) may still be used to irrigate off-site food crops and water farm animals near the SE Area. Potential receptor populations include local residents and anyone who consumes those produce and products. As long as food crops and farm animals are cooked, exposures to VOCs are not of public health concern, based on levels detected in springs/creeks thus far. However, metals, which may bioaccumulate or bioconcentrate in animal tissues, may be of concern if detected at levels of public health concern. Sampling of biota from off-site farms, near the SE Area, will occur in 1993. Also during 1993, a study will be conducted off-site at Rowe Run Spring to analyze groundwater flow rates and VOC concentrations at the spring. Those results will provide data to evaluate potential food chain exposure pathways.

Other off-site residential wells, not associated with past VOC contamination, were sampled in July 1991. Those wells were identified as a result of a residential well use survey. Those data are based on one sampling event. Lead was detected in several wells above the EPA action level of 15 ppb. Children are especially sensitive to lead exposure. Because lead is ubiquitous in the environment, any additional exposure to lead should be reduced. The source of lead contamination in off-site wells near the SE and PDO Areas may be associated with well piping. Those residents have been notified of their private well sampling results and referred to a health professional at the Pennsylvania Department of Health. They have also been advised of corrective measures that can be taken to reduce exposure to lead in water from the residential piping system. Persons with lead detected in their water above the EPA action level of 15 ppb should take precautions to reduce exposure to lead from their piping. During 1993, additional studies are planned by Letterkenny to determine if well piping is the source of lead contamination.

A completed pathway also exists to residents east of the SE Area through occasional accidental, occupational, and recreational exposure to contaminated springs and surface waters adjacent to the SE Area. That pathway continues to exist, but human exposure is not likely to result in adverse health effects because of the infrequent duration of exposure to low levels of VOCs detected in the open area. Other pathways of human exposure are restricted to the surface waters of the PDO Area. Those pathways involve recreational exposure in surface waters of the Rocky Spring Lake system and a food chain exposure resulting from the consumption of fish caught from the lake. Exposure to the surface waters of the PDO Area is not likely to result in adverse health effects because of the infrequent duration of exposure to low levels of VOCs and mercury detected in the open area. During 1993, sampling and analysis for mercury in fish tissue, algae, and lake and creek surface water from the Rocky Spring Lake system will be conducted. That information will further delineate potential and/or completed exposure pathways.

On-site deer in the AD/AS Area that are hunted and consumed represent a potential exposure pathway. Potential receptor populations may include installation personnel, their dependents, and guests (e.g. anyone who consumes the meat). As long as deer are cooked, exposures to VOCs are not of public health concern, based on levels detected in soil thus far. However, metals, which may bioaccumulate or bioconcentrate in animal tissues, may be of concern if detected at levels of public health concern. Further soil sampling and additional characterization are planned for the AD/AS Area in 1993. Those data will help to address potential pathways.

Community health concerns focus on potential long-term health effects that may occur from drinking contaminated private well water. Those health concerns are discussed in the Public Health Implications section of this public health assessment. No additional community health concerns were identified during the public comment period for this public health assessment.

Because there has been concern about potential health effects which may result from using past contaminated private wells and past exposure occurred to some compounds that are potential or probable carcinogens, available health outcome data from 1950 to 1979 and 1979 to 1981 have been evaluated for Franklin County. Evaluation of those data found no elevated cancer mortality rates for Franklin County. There are no community-specific health outcome data available for review.

ATSDR's Health Activities Recommendations Panel (HARP) has reviewed the data and information in the Public Health Assessment for Letterkenny Army Depot for follow-up health activities. Community health education has been conducted by the Army through established technical review committee meetings, public meetings, and individual meetings with concerned citizens. Letterkenny Army Depot continues to distribute environmental fact sheets to the public and communicate private well sampling results to homeowners whose wells have been sampled. Also, the Army has also provided an alternate water supply to residences with VOCs in well water at concentrations greater than EPA drinking water standards. Currently, there are no indications that adverse health conditions are occurring or have occurred from past exposures to Letterkenny contaminants. However, if during the site-characterization and remediation process, environmental or health outcome data become available that indicate human exposure to hazardous substances is occurring at levels of public health concern, ATSDR will reevaluate the sites to determine necessary followup.


BACKGROUND

A. Site Description and History

The Letterkenny Army Depot (Letterkenny), consisting of 19,520 acres, is five miles north of Chambersburg, in Franklin County, Pennsylvania (Appendix 1, Figure 1) (22). Although Letterkenny was established in 1942 with its primary mission being ammunition storage, the principal missions currently include storage and maintenance of ammunition, maintenance of wheeled and tracked vehicles, and issuance of chemicals and petroleum (2). Those activities (except those associated with ammunition) were conducted using significant quantities of trichlorethene (TCE), other chlorinated hydrocarbons, and other solvents.

Disposal and storage of hazardous wastes in two areas have created the two National Priorities List (NPL) sites at Letterkenny: USA Letterkenny Southeastern Area (SE Area) and USA Letterkenny - Property Disposal Office Area (PDO Area). They were listed on the NPL July 22, 1987 and March 17, 1989, respectively (8). Primarily, VOCs have been detected in groundwater, surface water, and soil at both NPL sites. Contaminants from the SE Area have migrated off-site and affected 41 private wells, rendering them unsuitable for potable use. Although those contaminated wells had been previously used as a potable water supply, the potential health impact could not be estimated due to the absence of exposure data. No follow-up health studies were recommended in that previous assessment, because no laboratory test was (or is) available to evaluate possible past exposures and no significant pathway of exposure has been present since the use of bottled and municipal water began in 1982 (22).

The Ammunition Disposal and Storage Area (AD/AS Area) lies outside of and is not part of either NPL site. The two NPL sites have been extensively studied; some remediation has occurred in both areas. Environmental studies for the AD/AS Area are underway to assess the potential for contamination. A map of these areas can be found in Appendix 1, Figure 2 (22, 28).

The Agency for Toxic Substances and Disease Registry (ATSDR) previously released a public health assessment for Letterkenny Army Depot on September 30, 1988 (Appendix 1). The SE Area and PDO Area were determined to be potential public health hazards due to the potential for contaminant migration. Since the release of that assessment in 1988, additional sampling, health data, and community information have become available, warranting an updated document. The figures and tables referenced in this public health assessment are provided in Appendices 2 and 3, respectively.

At least 52 potential contaminant source areas have been identified at Letterkenny based on past use of hazardous materials. Extensive testing of surface water, groundwater, and soil has indicated that seven of those 52 areas accounted for most of the past environmental releases of contaminants (2, 3). Those seven areas were within the SE and PDO Areas. At the SE Area, sources of contamination were as follows: (1) the K Area, (2) the industrial waste treatment plant (IWTP) lagoon, and (3) the storm sewer lines and industrial waste lines (Figure 6). At the PDO Area, sources of contamination were as follows: (4) Drum Storage Revetments, (5) Former Fire Training Pit, (6) Former Oil Burning Pit, and (7) Landfill Number 6, previously called the Open Landfill Area (Figure 7).

The previous IWTP Lagoon soils at the SE Area have been remediated and the lagoon is currently undergoing closure certification. The K Area soils are slated for low temperature treatment. At the PDO Area, the soils in the Drum Storage Revetments, Former Oil Burning Pit, and Landfill Number 6 do not warrant remediation (3, 106, 110, 119). However, groundwater sampling continues in the SE and PDO Areas and may be the focus of further studies. The following paragraphs below focus on the current efforts at the installation, describe historical background of previous contamination sources, and discuss future studies for the SE Area, PDO Area, and AD/AS Area.

Operable Units (OUs) for the two NPL sites have been established and recently updated. New OUs have been designated for each NPL site. OUs are usually areas that are grouped together according to how they will be cleaned-up or addressed in future studies. There are seven OUs in the SE Area and four in the PDO Area. The OUs in the SE Area are OU 1: K Area Contaminated Soils; OU 2: Industrial Waste Sewers and Contaminated Soils; OU 3: SE Area Contaminated Groundwater; OU 4: Storm Sewers and Contaminated Soils and Sediments; OU 5: Area A and Area B Contaminated Soils; OU 6: SE Area Off-Post Contaminated Groundwater; and OU 7: Truck Open Storage Area. The OUs in the PDO Area are OU 1: Source Areas (Oil Burning Pit and Drum Storage Revetments); OU 2: PDO Area Contamination (All Media); OU 3: Mercury in Rocky Spring Lake; and OU 4: Possible Groundwater Contamination Outside of the PDO Area (AD/AS Area and Off-site Residential Wells) (106, 107, 118). The identification of new OUs allows the CERCLA remedial process to continue without delay, while additional investigative work is performed for the previously established OUs (i.e., OU 4 in the SE Area).

Historical Background, Previous Studies, Remediation, and Future Fieldwork:

Southeastern Area: (SE Area)

K Area Soils: This area is behind Building 370, between East Patrol Road and Mortar Road. The three K Areas consisted of K-1 (a lagoon area about 189' x 78'), K-2 (revetments for trash/garbage storage about 20' x 60'), and K-3 (a drum storage area about 50' x 50'). Soils in two of those areas were contaminated as a result of past storage practices when hazardous wastes were stored in a lagoon and drum storage area (119). Storage of bulk materials also occurred here. Most of the areas were in use during the 1960s, but by 1970, aerial photographs indicate the areas had been covered with vegetation (15).

The SE Area Record of Decision (ROD) identified excavation of contaminated K Area soils (metals and VOCs) followed by low thermal treatment of the soils and the return of the treated soils to the original excavations (113). The contaminated soils in the K Area are scheduled for low temperature treatment so that there will be no need for future work at this site for cleanup of the soils (106, 119). A bench-scale treatability study has been conducted in this area to assess the efficiency of low thermal treatment and stabilization of the K Area soils (28). The Remedial Design Work Plan (RD WP) will include results from that study and specify how the remediation will be conducted. Treatment is expected to begin in July 1993 (106). Once the soils have been remediated, long-term monitoring of the groundwater is also proposed.

Industrial Waste Treatment Plant (IWTP) Lagoons: These concrete-lined lagoons were once situated about 100 feet from the IWTP, near the East Patrol Road and Gate Six. Beneath those lagoons were an older, unlined lagoon that was reportedly used to store sludges from the treatment plant and untreated industrial wastes. The older lagoon was used from 1954 until a sinkhole, formed in the underlying karst geology, was discovered in 1967. The same year, two concrete lagoons (designated 361 and 362) were built over the area and used as holding ponds for hazardous waste generated at Letterkenny until 1987, when cracks were discovered in the bottom of one of the lagoons (12). Studies by contractors have indicated that the lagoon area was once a main source of off-site groundwater contamination east of Letterkenny (5). A RCRA Closure Plan selected low thermal treatment of the soils in the lagoon area (28, 113). Remediation of them began on January 6, 1992 (50). That process included removing concrete, removing the soil down to the bedrock, thermally treating the soils, returning the treated soils to the original excavation, and capping the area. Lagoon closure was completed in November 1992, and closure certification is anticipated for early 1993 (28, 50, 106). Long-term monitoring and land use restrictions are planned for the area (13, 106).

Groundwater Treatment System (GWTP)--Building 365: Visible from State Route 997, along the East Patrol Road, is the Groundwater Treatment Plant (GWTP). It has been in operation since June 15, 1989, when cleanup of contaminated groundwater leaving the SE Area was initiated. This was undertaken in an attempt to prevent further migration of contaminated groundwater from the former lagoon area (10). However, it may take many years of pumping and treating the groundwater from the former lagoon area because of the cavernous porosity which characterizes the local limestone geology (5). The GWTP is enclosed within a metal building for winter protection and is about 300 feet northeast of the lagoons (28). The groundwater treatment system consists of nine on-site extraction wells, two air strippers operating in series, a vapor-phase carbon adsorption unit for the effluent air, and a liquid-phase carbon adsorption unit for the effluent groundwater (8). The system processes 120 gallons per minute. After treatment, the effluent is tested for total VOCs and total metals prior to being discharged into Rowe Run Stream, adjacent to the IWTP treated outfall (28). The system has treated more than 100 million gallons of contaminated groundwater since it began operation. This treatment system continues to operate without detectable limits of VOCs in the effluent (106, 107).

During 1993, a Groundwater Quality Assessment and Abatement Plan (GWAAP) will address the VOC contamination at Rowe Run Spring situated nearly two miles (off site of the SE Area) northeast of Gate 6. If actionable levels of VOCs are detected at Rowe Run Spring, a groundwater treatment system, compatible with the surrounding agricultural setting, will be considered for contaminant removal at the spring (106, 107). One off-site resident whose residential well contained low levels (below EPA Maximum Contaminant Levels) of VOCs will continue to receive bottled water until the Risk Assessment of the Rowe Run area is completed in 1993. Low levels of VOCs were detected in the well water when sampled in the summer of 1991 and December 1992 (106, 107, 118).

Industrial Waste Sewers and Storm Sewers; Contaminated Soils and Sediments: Based on field work conducted in the SE Area during 1991-1992, approximately 35 breaks in the storm sewer lines and 15 breaks in the industrial waste lines were determined. A soil gas study of the areas where the breaks were found will be conducted during the early months of 1993. Confirmed areas of leakage will then undergo a soil boring program to determine the extent of soil contamination. Based on those results, a contract will be initiated for interim repair of the confirmed breaks (106).

Area A and Area B Contaminated Soils: These areas are situated to the north of the K Area along the East Patrol Road and were used historically as an oil burn pit. Localized groundwater data from within Area B indicate the presence of lead and VOCs. Therefore, further sampling of Areas A and B is planned. For Area A, soils will be collected and analyzed for metals and VOCs. For Area B, the groundwater and soils will be collected and analyzed for metals and VOCs (118).

SE Area Off-Post Contaminated Groundwater: Further groundwater characterization (a dye-study) will be conducted off-site of the SE Area to help define the groundwater flow rates and contaminant concentrations in that area (118).

Truck Open Storage Area (North of Buildings 32/33): Soil will be collected and analyzed for metals and polynuclear aromatic hydrocarbons (PAHs) because this area has only been sampled for VOCs in the past (118). Additional sampling appears warranted because of historical use of this area.

Other Studies Related to the SE Area:

Surface water, sediment, and ecological sampling within the SE drainage basin (outfalls) were conducted in 1991. The samples were analyzed for VOCs, aromatic organics, and heavy metals, and the results will be released when the Remedial Investigation is finalized. Farm animal products from off-site farms adjacent to the SE Area will be collected and analyzed during summer and fall of 1993. Farm animal products, including beef, pork, poultry, eggs, and milk from a farm on Rowe Run Road will be analyzed for organics and metals (28, 30, 106, 107, 118). Milk samples will be collected from two farms in that area (119). Those results will be used in the preparation of the SE RA. The Final Remedial Investigation and Final Risk Assessment for the SE Area will be released to the public in late spring and fall of 1993, respectively (107).

Property Disposal Area (PDO):

Drum Storage Revetments: This fenced-in area, in the DRMO scrapyard within the PDO Area, was once used to store drums, surplus vehicles, wood, metal, and other debris. The area is comprised of 3,000 square feet and consisted of two adjacent, bermed areas used for storing 55-gallon drums containing hazardous waste. Between 200-300 drums of used oil, solvents, acids, pesticides, and other types of hazardous wastes were stored here until 1988 (3, 11). Those drums, the source of contamination, have since been removed (20). VOCs were detected in soil gas and groundwater in this area. However, VOCs were detected in the soil below the detection limit. Those sampling results support the conclusion that VOCs once present in the soils have migrated to the bedrock and groundwater and are volatilizing from the groundwater (3). Therefore, the Drum Storage Revetments are not considered a PDO Area contamination source as evidenced by the 1991 ROD for the area; no action was selected for the area (28, 106, 110).

Former Fire Training Pit: This pit, (called the Active Fire-Training Area in previous reports), was used from 1983 until 1987 to burn spent oils during fire fighters' training exercises. Located along Georgia Avenue, the pit was concrete-lined and approximately 58 feet by 58 feet in dimension. After its use was discontinued, it contained residual oil, sludge, and water. To eliminate a continuing spill threat posed by those residual elements, the pit concrete, underlying aggregate and stabilized sludge and oil were removed in December 1990 and disposed of off site as nonhazardous residual waste (119). This action was designated a CERCLA removal action. During the removal action, two areas of scattered bands of petroleum hydrocarbon-stained soil were observed (98). Sampling of soil and groundwater determined, however, that the stained soil was not contributing to groundwater contamination in the PDO Area. The excavation was lined with a plastic liner and backfilled with clean fill. A Decision Document detailing the removal action was prepared by the installation and reviewed and approved by the U.S. EPA and Pennsylvania Department of Environmental Resources (PADER). This document was finalized in September 1992 (106, 107).

Former Oil Burning Pit: Once called the Oil-Burning Pit, this area is at the intersection of Scalehouse Road and Georgia Avenue. The unlined pit was used from the early 1970s until May 1981 to burn spent oil. Occasionally, it was used in fire-fighting exercises (46, 47). VOCs were detected in soil gas and groundwater in this area. However, VOCs were detected in the soil below the detection limit. Those sampling results support the conclusion that VOCs once present in the soils have migrated to the bedrock and groundwater and are volatilizing from the groundwater (3). Therefore, the Former Oil Burning Pit is not considered a PDO Area contamination source as evidenced by the August 2, 1991 ROD for this area (106); no action was selected for the pit (28, 106, 110).

Landfill Number 6: Once termed the Open Landfill Area, this area is approximately 600 feet south of the Former Oil Burning Pit (46, 47). The types of waste disposed here are unknown. However, it is suspected that degreasing solvents were probably disposed here based on VOCs detected in soil gas and groundwater (3, 46, 47). VOCs were not detected above detection limits in the soils. Therefore, no action is warranted nor planned for the area (3, 46, 47, 106, 110).

Rocky Spring Lake: This area, in the southern portion of Letterkenny, is used for picnics and fishing; swimming is prohibited. Rocky Spring Creek feeds the trout holding pens and the man-made lake, Rocky Spring Lake (3).

Mercury in Rocky Spring Lake: During the fall of 1991, fish tissue, surface water, storm water, and soil were sampled for mercury from the Rocky Spring Lake vicinity. That sampling was conducted to follow up on mercury detected in lake surface water in June and July 1991. Mercury was not detected in soil and water samples (28, 106, 107). Mercury was, however, detected in the fish and duck tissue samples from Rocky Spring Lake, but the concentrations were comparable to national and regional background levels for mercury in fish and were well below the U.S. Food and Drug Administration (FDA) mercury action level for human consumption of fish.

On a biweekly basis from April through September 1992, fish tissue, algae, and surface water samples were collected and analyzed for mercury from Rocky Spring Lake. The Army Environmental Hygiene Agency (AEHA) performed a preliminary health risk assessment for human ingestion of fish containing mercury levels detected during the 1992 sampling effort. Mercury was reported to be detected at concentrations comparable to background concentrations and within human health and water quality standards (106, 107, 118, 119); however, the final report has not yet been released. During April through September 1993, fish tissue, surface water, and algae will again be sampled and analyzed for metals from those surface waters (118).

During the week of March 8, 1993, soil sampling for total metals, including mercury, was conducted near Building 1467 (a storage building adjacent to the Deactivation Furnace, Building 1456) which is situated several hundred yards upgradient from Rocky Spring Lake. The soils near this building are suspected to be a potential source of mercury in the lake (28, 106, 107, 118, 119), because mercury-containing munitions were stored on the ground near Building 1467. The area contains many spent shell casings on the ground surface (118). Mercury has been detected in one soil sample in one of two ditches draining Building 1467 in 1990 (119) and in Rocky Spring Lake water in 1991 (118).

Possible Groundwater Contamination Outside of the PDO Area--(Ammunition Area and Off-post Residential Wells): During the week of December 7, 1992, four off-site residential wells were sampled. Three residential wells were sampled for metals and one residential well was sampled for VOCs. This sampling was a follow-up to a summer 1991 sampling that detected lead, mercury, and VOCs in private wells. Lead was detected in two wells above the EPA action level of 15 ppb (54.4 and 24 ppb). Mercury was detected in one well (near orchards) at 0.6 ppb, and VOCs were detected in one well near Rocky Spring (total VOCs detected were 6.4 ppb). The persons with lead detected in their well have been referred to health professionals at the Pennsylvania Department of Health. Resampling of off-site wells are planned to determine if there is an association between the metals and VOCs detected in those wells and Letterkenny's groundwater system. The well in which total VOCs were detected has been sampled several times since the mid-1980's. All past groundwater data for that one well will be reviewed to assess if the organics in the well match the Letterkenny organics contamination profile (106, 107). In 1993, a hydrogeological study will be conducted and may help further delineate potential/completed exposure pathways.

Other Studies Related to the PDO Area:

Release of the Final Remedial Investigation and the Final Risk Assessment for the PDO Area are scheduled for spring of 1993, respectively (106, 107).

Ammunition Disposal and Storage Area (AD/AS Area): This area, the largest tract on post, is primarily used to dispose of and store ammunition. It is northwest of the SE Area. In June of 1990, a Site Investigation (SI) was initiated at 17 Solid Waste Management Units (SWMUs) in the area to determine whether additional SWMUs should become a separate RI/FS effort (28). That investigation indicated that some sites require further study, while other sites warrant no further action because they are considered "clean" for purposes of CERCLA and the NPL program (28, 45, 106, 107, 108). The following SWMUs have either no or very low levels of contamination and, therefore do not warrant further study: Acid Burning Pit, Open Burning Ground No. 1, Ammo Box Piles, Demolition Ground No. 1, Autocraft Shop - Waste Oil Tank, Building No. 3700, Classified Paper Incinerator Area, Residue Burial Site, Ingot Pig Storage (LOT 29), and the Deactivation Furnace.

The remaining SWMUs investigated in the 1991 SI are characterized by the following chemicals: 1) Demolition Ground No. 2 - explosives, magnesium, and thallium; 2) Open Burning Ground No. 2 - explosives and metals; 3) Burning/Neutralization Pit - VOCs and arsenic; 4) TNT Washout Plant - explosives; 5) Buried Drums Site # 1 - metals, possibly drums; 6) Buried Drums Site # 2 - metals, possibly drums; 7) Ingot Pig Storage (LOT 48) - lead; and 8) Transformer Pad - PCBs and pesticides. In 1993, further study of those SWMUs may confirm and delineate the extent of contamination (106, 107, 108). The Transformer Pad and Ingot Pig Storage (LOT 48) are located in the SE Area, and the remaining SWMUs are in the AD/AS Area (118).

Two sites, the Buried Drums No. 1 and No. 2 areas, were detected by geophysical survey methods to include areas of probable high concentrations of metals, possibly drums, which warrant further investigation by direct sampling methods. No contamination data were gathered for those sites in the Site Investigation (45). The status of those areas as potential sources of contamination will be determined by future studies conducted in 1993.

During the summer and fall of 1993, trenching will be conducted at the Buried Drum Sites No. 1 and 2 to locate any possible buried drums; soil sampling will be conducted at the TNT Washout Plant, Demolition Ground No. 2, Burning Ground No. 2, Neutralization Pit, Transformer Pad, and Ingot Pig Storage (LOT 48). Groundwater samples will be collected from the TNT Washout Plant, Demolition Ground No. 2, and Burning Ground No. 2. That field work is tentatively scheduled for the summer of 1993 (118); analysis will most likely be conducted in the fall of 1993. Those results will appear in an SI Addendum Report (106, 107, 108, 118). Until data are gathered for those SWMUs, it is not possible to accurately assess potential contamination at the SWMUs at this time. Data gathered from ongoing or future studies may identify new contaminants of concern or define pathways of contamination not currently delineated.

Off-Site of Letterkenny:

Rowe Run Spring:
The surface water flow down Rowe Run is increased by springs at various places, including Rowe Run Spring and Pinola Spring. The groundwater flows off the installation in a southeasterly direction and first surfaces as Rowe Run Spring, about one and one-half miles east of the Southeastern Area boundaries of Letterkenny (2). During dry periods, the spring is intermittent, resulting in infrequent surface water conditions. A dye-tracer study has shown that this spring is supplied groundwater from the SE Area on Letterkenny (119).

Pinola Spring: Groundwater surfaces again at Pinola Spring about three and one-half miles east of the Southeastern Area boundary of Letterkenny (2).

B. Site Visit

ATSDR conducted a site visit to Letterkenny Army Depot on January 9-11, 1991. ATSDR staff and regional representatives were present. Also present during the site visit were representatives from the U.S. Environmental Protection Agency (EPA), U.S. Army Environmental Hygiene Agency, Letterkenny Army Depot (AEHA), Pennsylvania Department of Health (PADH), and Pennsylvania Department of Environmental Resources (PADER).

The installation tour included meetings with the commanding officer and personnel from the engineering, legal, environmental, natural resources, and public affairs offices. The two NPL sites and other areas of interest were inspected. The observations made during the January 9-11, 1991 site visit by ATSDR that relate to public health are summarized here. Please refer to Appendix 4 for detailed site-specific observations (20).

Although the installation is fenced and access is controlled at two guarded gates, installation and remediation personnel have potential access to contaminated areas. Installation personnel and guests may hunt in the AD/AS (undergoing additional environmental characterization). Hunting is not permitted in the SE and PDO Areas (106). Residents may fish the lake, but swimming is not allowed in the Rocky Spring Lake.

Forty-one off-site wells, east of the SE Area, were replaced by bottled water, and eventually municipal water, when they were detected with VOCs exceeding MCLs. Most of those wells were at private residences and a few were at local businesses. The area where those wells are situated is largely characterized as rural and agricultural. Many of those residents, still can use their private wells to supply water to irrigate crops, lawns, fruit trees, and gardens and to water farm animals, including cattle, dairy cows, pigs, and poultry (1, 3, 11, 29, 30).

C. Demographics, Land Use, and Natural Resource Use

Demographics

Most of the information presented is from the 1990 census; however, data on housing conditions and median household income, are not yet available. Data presented for those parameters are from the 1970 and 1980 censuses.

The Letterkenny Army Depot is five miles north of Chambersburg, within three townships: Greene, Letterkenny, and Hamilton. Chambersburg, with a 1990 population of approximately 16,647 persons, is the county seat of Franklin County (1990 population of 121,082). According to 1990 census figures, Chambersburg is predominantly white (90.6%), with the remaining racial composition being black (7.2%), and other races (2.2%). A fairly high percentage of the Chambersburg population, 22.3%, are 65 years of age or older, indicating a more stable, less transient population. Only 51.5% of the households in Chambersburg are owner-occupied; there are 2.19 persons per household, which is fairly low compared to the county (9). The demographics for Franklin County and Chambersburg are presented in Figure 1 in Appendix 3.

Letterkenny is the largest employer in Franklin County (22), Pennsylvania, employing about 4,920 civilians and 90 military personnel (112). Approximately 45 of the 90 military employees (50%) live on-site (112). No other current demographics are available for the military or civilian population (18).

Population and housing data for the census blocks within the area where off-site wells, near the SE Area, were abandoned as a drinking water supply are available for 1990 but not for 1980. However, a comparison of 1980 and 1990 census tract level data reveals very few substantial changes over the decade, so the 1990 figures for those blocks should be representative of the 1980 figures (14, 39). Population and housing figures for 1990 for the area where wells were replaced near Letterkenny (Figure 2) are similar to those for the county (Figure 1). Nearly all persons are white. Nearly 78% of households are owner occupied; this trend suggests a nontransient population. Average persons per household (2.56) is nearly identical to the county average. Using that number (2.56) and the number of wells that were replaced with an alternate water supply (41 wells), approximately 105 persons might have been exposed in the past to contaminated well water. The range of concentrations and length of time they may have been exposed are unknown. The mean value of owner occupied housing and mean monthly contract rent are also very similar (14). The population density of 183 persons per square mile is relatively low and is typical of a largely rural area.

Three nursing homes are five or more miles from Letterkenny: Shook, Menno Haven, and Franklin County (106). According to the local chamber of commerce, all of those homes are using municipal water for drinking water and other household purposes (7).

A day care center for pre-schoolers of military and civilian employees is situated in the middle of the PDO Area, several hundred yards upgradient of Rocky Spring Lake (21, 106). Letterkenny has its own potable water source, (supplied from Letterkenny Reservoir, about eight miles north of Letterkenny) treatment and distribution system (2, 106). The day care center uses this potable water system.

There are approximately six schools within 5 miles of Letterkenny. All of them are connected to the municipal water system (17).

Land Use

Letterkenny is bordered to the north by State Route 533 and to the south by Boundary Road. The western boundary consists of the Buchanan State Forest and State Game Lands, and the eastern boundary consists of State Road 997 (23). Overall, the areas surrounding Letterkenny are primarily rural and agricultural (Figure 3).

Principal land uses north, east, and south of Letterkenny are farming and raising livestock (beef cattle, dairy cows, and pigs). Principal crops are fruit trees (including apples, pears, peaches), and corn (1, 6, 119).

Industries critical to Franklin County's economy include manufacturing, wholesale and retail trade, food processing, and agriculture. The county produces approximately four percent of Pennsylvania's total agricultural sales, with major crops being apples, peaches, cherries, and dairy products. Commercial food processors in Franklin County are Knouse Foods Cooperative, Inc.; Pet, Inc. (6); Borden's, Inc (28); Kraft, Inc.; and Nibble with Gibbles snack food products (6).

Natural Resource Use

The majority of residences and businesses off-site are connected to the Guilford Water Authority System. However, there are a few areas that use private wells for drinking water and other household purposes. Along the northeast, east, and southeast areas adjacent to the SE Area (Gate 6, Figure 4) and along the south and southwest areas adjacent to the PDO Area (Gate 1, Figure 5), residents use private wells for drinking water and other household purposes (28). Letterkenny Army Depot has its own potable water treatment and distribution system. Currently, the water is supplied from Letterkenny Reservoir, about eight miles north of the facility (2).

Letterkenny residents and guests hunt on site for white-tailed deer and small game (including squirrel, rabbits, foxes, and pheasants) within two hunting zones (21, 31) restricted to the AD/AS Area. There are some deer in the PDO Area, but they are not hunted and are isolated from deer in the AD/AS Area by an 8-foot, chain-link fence (106). Zone I includes 12,000 acres and is open only to Letterkenny civilian employees, military personnel, and retired military staff, their dependents, and their guests. Zone II covers 5,000 acres and is open to the public. Obtaining permission to hunt on Letterkenny is an involved process. All hunters must show proof of a valid Pennsylvania license, the appropriate tags for the season and hunting weapons. They must also complete a hunter safety course and attend an installation hunting briefing (31).

Fishing, but not swimming is allowed in the Rocky Spring Lake (2). Fishing is open only to Letterkenny civilian employees, military personnel, and retired military staff, their dependents, and their guests. Those persons must abide by the Pennsylvania licensing requirements by having an installation permit also (31). Although the lake has been stocked primarily with rainbow trout, it is also inhabited by brown trout, brook trout, large-mouth bass, crappie, catfish, and bluegills (28). The lake is fed by Rocky Spring (Figure 1, Appendix 1) which feeds a trout holding pen at the beginning of the lake. Rocky Spring Lake is also used for boating as well as a gathering place for cookouts/picnics at Letterkenny (20). Rocky Spring Creek begins below Rocky Spring Lake.

Off-site residents hunt deer, squirrel, rabbits, fox, pheasant, and other small game off-site in most areas surrounding Letterkenny. However, most hunting takes place in state game lands (Figure 3, Appendix 2) west of Letterkenny (21).

D. Health Outcome Data

This section identifies relevant, available databases for health outcome data, and the evaluation of those data is presented in the Public Health Implications section of this public health assessment. Persons within the local and state health department and nearby universities were contacted to obtain information about available health outcome data (32-36). However, only two databases were detected to be relevant to this assessment; those databases are discussed in the following paragraphs.

The Pennsylvania Department of Health provided data on cancer mortality and census information from the state of Pennsylvania and from three townships: Greene, Hamilton, and Letterkenny. Letterkenny Army Depot spans all three townships (36). Population data included age-sex distribution of the three townships and average annual sex-specific death rates of Pennsylvania from 1979 through 1981. Data provided in Tables 1-3 (Appendix 3) and a discussion of the results are in the Health Outcome Data Evaluation section of this public health assessment.

Cancer mortality rates from the EPA/National Cancer Institute (NCI) Riggans Mortality data compiled for the years 1950 through 1979 are presented and discussed in the Health Outcome Data Evaluation section.


COMMUNITY HEALTH CONCERNS

ATSDR gathered community concerns through conversations with Chambersburg citizens (37, 38), meetings with regional representatives, Letterkenny personnel, and various state and federal representatives. ATSDR also reviewed various information in the public affairs complaint log along with the Community Involvement and Response Plan for Letterkenny.

According to the complaint log, community health concerns were the greatest after the installation discovered off-site contamination in private wells. For instance, during 1988, Letterkenny evoked congressional and executive interest when a private citizen wrote the President and several state U.S. senators to express her concerns about health effects from drinking large amounts of well water prior to receiving municipal water. In addition, a group of Chambersburg citizens, primarily concerned about groundwater contamination, have met with Letterkenny personnel (20). However, since Letterkenny provided municipal water to residents in 1987, concerns have diminished (37, 38). The predominant concern has been about possible health effects that may have occurred from ingesting the contaminated groundwater. No additional community health concerns were identified during the public comment period for this public health assessment. Community health concerns identified from the Community Involvement and Response Plan are summarized below:

  1. What are the potential long-term health effects from ingesting contaminated well water?
  2. Will well water will be safe to use again in the future?
  3. Is the incidence of cancer on my neighbor's street unusually high, and is it related to the contaminants from Letterkenny Army Depot?

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