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PUBLIC HEALTH ASSESSMENT

LORING AIR FORCE BASE
LIMESTONE, AROOSTOOK COUNTY, MAINE


ENVIRONMENTAL CONTAMINATION/ PATHWAYS
ANALYSIS/PUBLIC HEALTH IMPLICATIONS

We describe here one situation in which significant concentrations of contaminants are present,but measures are in place to prevent exposure; a second where measures prevent possible futureexposure; and a third where remedial activities will prevent future exposures to hazardous levelsof contaminants. In three other situations, low levels of contamination are present, but no one isbeing exposed or expected to be exposed in the future at concentrations of concern. In thissection we will discuss available information that relates to our analysis and suggest means tomitigate risks. When appropriate, we list additional information that should be gathered in asituation to add data necessary for a complete determination.

ATSDR's public health assessments are exposure, or contact, driven. Chemical contaminantsdisposed of or released into the environment at LAFB have the potential to cause adverse healtheffects. However, not all releases result in exposure. Persons can only be exposed to a chemicalif they come in contact with that chemical. Exposure may occur by breathing, eating, or drinkinga substance containing the contaminant or by skin (dermal) contact with a contaminated substance.

The type and severity of health effects that occur in an individual from contact with acontaminant depend on (a) exposure concentration (how much), (b) frequency and/or duration ofexposure (how long), (c) route or pathway of exposure (breathing, eating, drinking, or skincontact), and (d) the multiplicity of exposures (combination of contaminants). Once exposureoccurs, characteristics such as age, sex, nutritional status, genetics, lifestyle, and health status ofthe exposed individual influence how that individual absorbs, distributes, metabolizes, andexcretes the contaminant. Together these factors and characteristics determine what healtheffects may occur as a result of exposure to a contaminant.

I. NO APPARENT PUBLIC HEALTH HAZARD

ATSDR concluded that three situations concerning the LAFB installation pose no apparentpublic health hazard: 1) catching fish from waters affected by base-associated contaminants, 2)drinking water from off-site or on-site water wells, and 3) wading and swimming in on-site waterways.

A. Catching Fish from Waters Affected by Base-Associated Contaminants

Evaluation of chemical and toxicologic data from analysis of fish fillets sampled from certainsurface waters on-base and off-base showed increased carcinogenic and noncarcinogenic risks from eating such fish. Fish taken from the West Branch, Greenlaw Brook (WBGB), MalabeamLake, Chapman Pit Pond, Green Pond, and East Branch, Greenlaw Brook (EBGB) (entirely orprimarily on-base) and from Greenlaw Brook, the lower Little Madawaska River (downstream ofbase influence), and Wolverton, Brandy, Factory, and Nichols Brooks (entirely or primarily off-base) contain contaminants at levels of concern (Figure 2). The greater risks result fromincreased concentrations of polychlorinated biphenyls (PCBs) from Arochlor 1260 (most of theabove-cited waterways) and from elevated polycyclic aromatic hydrocarbons (PAH) levels(Malabeam Lake only), contaminants that are associated with past base activities. Backgrounddata were gathered from water bodies north of the base, such as Butterfield Lake, which are notimpacted by on-base contamination. The lower risk associated with background sites is duemainly to residues of DDT and its two major degradation products remaining from earlierwidespread use of DDT in agricultural areas. The risk equation, values substituted for thevarious parameters, and a sample calculation are shown in Appendix C.

The risk values for consumption of fish caught in the above-mentioned waters exceed the MaineDepartment of Human Services (MDHS) cancer guideline. As a result, MDHS established acatch-and-release fish advisory in 1996 that warns against ingestion of fish taken from the LittleMadawaska River (LMR) and its tributaries between the Little Madawaska Reservoir Dam andGrimes Road, just upstream of the confluence of the LMR with the Aroostook River (Figure 2).5 (Figure 3 shows the location of the LMR and tributaries relative to LAFB boundaries). A fishadvisory was enacted and publicized to protect the public from risks associated with eatingcontaminated fish from these waters.

The MDHS advisory and an accompanying fact sheet were distributed widely to print media,radio and television stations, community groups, and individuals. Affected water bodies wereposted to reflect the catch-and-release edict. Details of the fishing advisory have now beenincluded in the Maine 1998-1999 Open Waters Fishing Regulations provided to everyonepurchasing a fishing license in Maine, alerting anglers to risks inherent in consuming fish fromdesignated waters.

PCB levels in fish are expected to drop over time. The BRAC Cleanup Team (BCT) projectsthat concentrations of PCBs will be low enough in five to ten years for the fish advisory to belifted.6 A plan should exist and be funded by AFBCA to monitor PCB levels in fish at three- to-five-yearintervals and to include samples taken from Green Pond, Greenlaw Brook, and the LMR.

Low levels of DDT, DDE, and DDD found in fish from Butterfield Brook and East Loring Lakeon LAFB are thought to be due to widespread spraying of DDT in years before use of DDT wasbanned in the United States and not associated specifically with former base activities. The lessthan 1 milligram/kilogram (mg/kg) total concentrations found do not represent a public health hazard at the consumption rates that may be reasonably associated with fishers of these waters.

Several considerations argue against significant past exposure of persons to PCBs in fish at or near LAFB. PCB concentrations undoubtedly were smaller in the affected waterways previously, since PCB contamination resulted cumulatively during the years of LAFB operation. Also, theLMR, a much larger fishery than the EBGB, has the fish with lower PCB levels. Additionally,anglers have had an abundance of alternative fishing waters in the nearby area. Finally, a studyby Duggan et al.7,8 in 1983, part of a federal monitoring program conducted by the U. S. Foodand Drug Administration (FDA) and the U.S. Department of Agriculture (USDA), measuredPCB concentrations in dairy products and raw meats in the United States during the years 1970 to1976. Forty-six percent of 2901 samples of fish were positive for PCBs, and all 2901 resultswere averaged to yield a result of 0.892 ppm (g/g) in fish. This value, reflective of fishmarketed for human consumption throughout the United States in the 1970s, is comparable toconcentrations found in fish from the EBGB and LMR at the inception of the MDHS fishadvisory (Appendix C). The FDA has established an upper limit of 2 ppm (g/g) of PCBs infood fish to protect the public from harmful health effects.9 The MDHS fish advisory is morerestrictive than the FDA requirement for PCBs in fish. It is unlikely that any adverse healtheffects have occurred in the past that are attributable to PCBs in fish from waters covered by thefish advisory.


Figure 2. Location of Fish Advisory


No Apparent Public Health Hazard Situation: Fish in Waters Affected by Base-Associated Contaminants
PATHWAY NAME CONTAMINANTS EXPOSURE PATHWAYS ELEMENTS TIME COMMENTS
SOURCE ENVIRONMENTAL MEDIA POINT OF EXPOSURE ROUTE OF EXPOSURE POTENTIALLY EXPOSED POPULATION
Contaminated fish in the lower Little Madawaska River and site-associated tributaries, on-base and off-base.

PCBs*, PAHs**, pesticides

Releases of hazardous substances to soils, surface water, and groundwater from flight operations, from transformer leaks and other PCB spills, and from disposal on base

Fish

Eating contaminated fish

Ingestion

Potentially Exposed:
People who eat fish in spite of the fish advisory for those waters stipulating a policy of catch-and-release.

Past
Current
Future
Details of the State of Maine fish advisory proscribing consumption of fish in the affected waters are now included in the Maine 1998-1999 Open Water Fishing Regulations provided to all purchasing a fishing license.
*PAHs - polycyclic aromatic hydrocarbons
**PCBs - polychlorinated biphenyls

Conclusions and Public Health Action Plan: Fish from Waters Affected by Base-Associated Contaminants and Covered by the Maine Department of Human Services Fish Advisory, Issued April 18, 1996.

Conclusions:

  1. Persons consuming weekly, eight-ounce meals of fish taken from the Little Madawaska River and its tributaries between the Little Madawaska Reservoir Dam and Grimes Road, just upstream of the confluence of the LMR with the Aroostook River, have an elevated risk for cancer over a 70-year lifetime exposure.

  2. Adherence to the current fish advisory eliminates this risk.

Action in Effect:

The Maine Department of Human Services established a fish advisory that warns against ingestion of fish taken from the LMR and its tributaries as described in the conclusion above. The advisory advocates a policy of catch-and-release in these waters, including the on-base portions of Greenlaw Brook, until such time that contamination is demonstrated to have abated to a point where fish consumption no longer represents a health hazard.

Recommendation:

We recommend to AFBCA that a plan be in place and funded to monitor contaminant levels in fish at three- to five-year intervals, including samples taken from Green Pond, Greenlaw Brook, and the LMR, and that the levels found be compared to guidelines existing at the time to permit modifying or lifting of the MDHS Fishing Advisory when appropriate.

B. Drinking Water from On-Site or Off-Site Water Wells

1. On-Site Wells: Numerous water supply wells have been installed on-site at LAFB, beginningwith the initiation of construction of the base around 1947 and continuing until at least 1985. Most of the wells were constructed in the period from the late 1940s through the middle 1950s. There are at least 35 such wells on base.10 None of these wells are now used to supply drinkingwater on the installation.11 In 1957, when the output of the wells was projected to be insufficientfor future LAFB needs, the Little Madawaska River (LMR) Reservoir facility was constructed tosupply the base. Although the main water system at Loring has been supplied exclusively fromthe LMR Reservoir since completion of the facility in 1960, individual wells supplied potablewater to persons at a few remote locations on the installation until the base was closed in 1994. Extensive, low-level groundwater contamination resulted on the developed western portion of thebase from previously accepted hazardous material handling and disposal practices at LAFB. However, the deep groundwater is typically in a discharging (artesian) condition in the areas ofsignificant surface water and groundwater contamination, i.e. the FLDD, FLDD Wetland, and theEBGB. Thus, shallow groundwater is forced to the surface and carries attendant contamination,if any, down the EBGB, not to deeper groundwater aquifers. When remediation is complete atLoring, most water supply wells will have been abandoned and sealed according to acceptablecriteria. The BCT is developing a long-term, groundwater monitoring plan that should beavailable in early 1999; this plan will stipulate which wells will be retained as monitoring wellsor for other potential uses and which will be abandoned and sealed.6 No-pump areas andcompliance boundaries will also be identified. Parcels transferred to new owners will be conveyed by deeds stipulating restrictions on installation of potable-water wells on the properties. Potable waterwill continue to be available from the LMR Reservoir for properties transferred through the Loring Development Authority.

What was to become LAFB was constructed from forest and wetland in the late 1940s and early1950s. Water wells on LAFB supplied all base needs from the arrival of the first Air Force unitin 1950 until the LMR Reservoir came on line in 1960. Negligible contamination ofgroundwater occurred during this period, and the primary water source has been theuncontaminated reservoir water ever since. Five wells have provided potable water duringperiods after 1957 to a limited number of persons. Well # 20 and its backup, Well # 9, suppliedup to 100 persons in the Weapons Storage Area of East Loring for eight hours per day from 1952until 1994.12 These wells are in deep bedrock at depths of 323 and 275 feet, respectively. Thereis moderate contamination of shallow groundwater in this area; however, bedrock in this areashows low transmissivity below 45 feet. There is an upward hydraulic influence (water at lowerlevels in bedrock exerts upward pressure) and the shallow bedrock has been shown to dischargeto overburden which, in turn, discharges to surface water (East Loring Lake and ButterfieldBrook).13 Significant levels of contaminants do not travel to the depths from which the wellsdrew water when they were in use. The DRMO Well, also on East Loring, was in service duringthe years 1966 to 1994 and served a small number of persons. This well is in an area with littlegroundwater contamination and not within a designated groundwater flow field, an area ofconcern defined by demonstrated groundwater contamination, potential flow pathways, anddischarge zones. The sewer treatment plant water well remains in service on base but is nolonger used for drinking water purposes. Also, neither this well nor the weather station well arelocated in a designated OU12 flow field. The ski chalet well supplied drinking water to guests inthe past but is no longer used to provide potable water. The low levels of groundwatercontamination in the areas of these latter four wells make it unlikely that any contamination ofwater in the wells has occurred. There is no indication of past exposures to contaminants indrinking water on base that would have posed a health hazard. Currently, no exposures tocontaminated drinking water are occurring. Deed restrictions limiting construction of new wellson transferred properties are designed to prevent future exposures to contaminated drinkingwater.

2. Off-Site Wells: The Air Force undertook sampling of private wells at the East Gate Estatesand West Gate Villa mobile home parks. Wells within a 0.5 mile radius of the Receiver Site, Landfills #2 and #3, and the Fuels Tank Farm/East Gate Waste Storage Tanks were also selectedfor sampling. Sampling and chemical analysis were to address concerns that on-basecontaminants might have migrated to these wells. An ATSDR Health Consultation released inFebruary 1993 addressed the results of the chemical tests.14 Eleven of 13 properties served bywells meeting the criteria for testing were sampled. The owners of the other two propertiesshared another well, but attempts to arrange sampling in the same round were unsuccessful. Manganese was the only contaminant of public health concern identified. This contaminant wasdetected at a concentration of 1840 mg/kg in the well at Carpenter's Service Station. ATSDRconcluded that the well could be safely used for such activities as washing cars but should not beused as a residential or business drinking water source. The manganese is not believed to beassociated with the LAFB installation.14 A copy of the February 1993 consultation is included in the present document as Appendix D.

Since the publication of the 1993 health consultation (Appendix D), the remaining well has beensampled and analyzed. All analyte concentrations were below levels of concern.15 Another welllocation has been identified that meets the original criteria for sampling off-base wells, but, basedon known groundwater contours and monitoring-well-sampling results, the resident is not atrisk.16 The nearest downgradient well to Landfill 2 (Well G-H) is being sampled on an annualbasis. No contaminants have been found in this well at concentrations of concern. Monitoringwells just off base and to the northwest of Landfill 2 yielded samples showing vinyl chlorideconcentrations in the range of 0.15 to 1.0 parts-per-billion (ppb), where Maine's screening valueis 0.15 ppb and the USEPA's is 2.0 ppb.6 The direction of groundwater flow in the area is to thenorthwest. No concentrations above screening values have been seen for vinyl chloride or anyother contaminants in the array of monitoring wells to the west, between Landfill 2 and Well G-H. No evidence of past or current exposures to contaminants in drinking water from off-basewater wells has been seen. Long-term monitoring of OU12 and OU4 groundwater is designed toprotect the purity of off-base water wells in the future.



Table 2.

No Apparent Public Health Hazard Situation: Drinking Water from On-Site or Off-Site Water Wells
PATHWAY NAME CONTAMINANTS EXPOSURE PATHWAYS ELEMENTS TIME COMMENTS
SOURCE ENVIRONMENTAL MEDIA POINT OF EXPOSURE ROUTE OF EXPOSURE POTENTIALLY EXPOSED POPULATION
Basewide groundwater
(OU12) and on-site water wells

Fuel-related compounds, VOCs (including chlorinated solvents), pesticides, metals

Releases of hazardous substances to soils, surface water, and groundwater from flight operations and support functions

Groundwater
(OU12)

Water from taps in on-base locations that rely on wellwater Ingestion, direct contact, or inhalation (of vapors) of contaminated wellwater Potentially Exposed:
Persons drinking water from a on-base water well that becomes contaminated
Past
Current
Future
No wells on the Loring facility are known to be used currently for drinking water. Potable water has been supplied from the Madawaska Reservoir water system since 1960. Conveyance of parcels will include stipulations against constructing wells to provide water for drinking purposes.
Basewide groundwater
(OU12) and off-site water wells

Fuel-related compounds, VOCs (including chlorinated solvents), pesticides, metals

Releases of hazardous substances to soils, surface water, and groundwater from flight operations and support functions

Groundwater
(OU12)

Water from taps in private residences or businesses nearby (<1 mile) that rely on wellwater

Ingestion, direct contact, or inhalation (of vapors) of contaminated wellwater Potentially Exposed:
Persons drinking water from an off-base water well that becomes contaminated
Past
Current
Future
Off-base water wells near the installation have tested free from base-associated contamination. Measures are in place to assure that these wells will not be impacted in the future by unacceptable levels of contaminants from OU-12 groundwater.
Landfill-associated groundwater (OU4) and off-site water
wells
Fuel-related compounds, VOCs (including chlorinated solvents), pesticides, 2,6-dinitrotoluene, metals Landfills two and three Groundwater
(OU4)
Water from taps in private residences or businesses nearby (<1 mile) that rely on wellwater Ingestion, direct contact, or inhalation (of vapors) of contaminated wellwater Potentially Exposed:
Persons drinking water from an off-base water well that becomes contaminated
Past
Current
Future
Off-base water wells near the installation have tested free from base-associated contamination Landfill effluents will be monitored for at least 30 years after closure of the landfills to evaluate and mitigate any threat to aquifers.

VOCs - Volatile Organic Compounds

Conclusions and Public Health Action Plan: Drinking Water from Off-Site or Approved On-Site Water Wells

Conclusions:

  1. The LMR Reservoir provides a safe, abundant, and reliable source of potable water that is a superior alternative to wellwater for current and projected future needs for the Loring complex.

  2. Groundwater contamination on the Loring installation does not pose a contamination threat to off-base private water wells.

Planned Actions:

  1. A long-term groundwater monitoring plan will be developed and drafted by the AFBCA and the OU12 contractor for consideration and modification as negotiated within the BRAC Cleanup Team (BCT). The approved plan is expected to stipulate which wells on Loring property (water-supply, monitoring, and others) will be retained and which abandoned. Those to be abandoned are to be sealed by acceptable methods (State of Maine protocols) to remove potential conduits for spread of contaminants in shallow groundwater to deeper aquifers.

  2. Deeds to transfer parcels to new owners will include stipulations restricting installation of water supply wells.

Recommendation:

ATSDR requests that it be provided a copy of the long-term groundwater monitoring plan for review when the plan becomes available in draft form for comment.

C. Wading and Swimming in On-Site Waterways

Considerable data are available to evaluate risks that might be posed by contamination in brooks,streams, and ponds on the Loring installation. Much of this information is contained in theBasewide Surface Water/Sediment Operable Unit (OU13) Remedial Investigation Report.17 TheBCT calculated acceptable risks and corresponding soil and sediment cleanup levels based onfuture land-use scenarios (residential, recreational, industrial/commercial) as defined in theRecord of Decision for Disposal of Loring Air Force Base, Maine, April 1996.1 AFBCAcontractors performed removal actions as necessary, guided by analytical results.

Wolverton Brook and Brandy Brook are southwestwardly flowing tributaries of the LittleMadawaska River, which itself flows south toward its confluence with the Aroostook Riversoutheast of the town of Caribou (Figure 2). The Wolverton Brook/Brandy Brook Study Area islocated along the western side of LAFB and is approximately 4600 acres in size, about 700 acresof which are within LAFB boundaries (Figure 3). Risks were calculated for a scenario positingchild trespassers, 6 to 16 years of age, experiencing recreational exposure to contaminants insurface water and sediment while wading and surface soil while playing.18 Risks for surfacewater, sediment, and soil pathways were less than the MEDEP cancer guidance value of 10-5, thevalue accepted by ATSDR for this public health assessment as being protective of public health. This guidance value corresponds to a 1 in 100,000 (0.00001) increase in the lifetime risk ofcancer from spending 26 days/year for 11 years wading and playing in this area. The doses ofnoncarcinogenic contaminants were smaller than quantities that could result in health effects. Wading and playing in the Wolverton Brook/Brandy Brook Study Area pose no apparent publichealth hazard.

The Flightline Drainage Ditch (FLDD) is located in the south-central part of the base, west of theflightline and south of the nose-dock area. The FLDD is a 20 to 25 feet wide, about 2,500 feetlong, unlined, drainage channel. The FLDD extends from a triple-culvert headwall and drainsthe flightline area. It passes through the Spill Containment Facility (SCF), continues through theFLDD wetland, and flows into the East Branch of Greenlaw Brook (EBGB), which joins theWest Branch of Greenlaw Brook (WBGB) before the confluence of Greenlaw Brook with theLittle Madawaska River (Figure 3).

The January 8, 1997, ATSDR Health Consultation for LAFB recommended that wading in theFLDD be prohibited due to risk attributable to levels of PCBs found in water sampled from theFLDD/FLDD wetland area.19 Cancer risks greater than 10-4 were calculated20 for the trespasserchild (6 to 16 years old), substantially higher than the MEDEP permissible value of 10-5. However, the ban on wading prevented such exposures. A remedial action was undertaken inthe summer of 1997 to excavate areas of the FLDD, FLDD Wetland, and EBGB to remove PCBsand other contaminants. Work was completed on the FLDD and FLDD Wetland during 1997. There was confirmatory analysis of sediment and water by AFBCA contractors demonstrating achievement of the acceptable concentrations of 1 ppm PCBs in stream sediment and 5 ppm in flood-plain sediment in the completed areas.6, 21 The ban on wading has been lifted from theFLDD and none will be imposed on the FLDD Wetland. The remediation plan is set out in theRecord of Decision for OU13. Remaining excavation work, essentially that on the EBGBdownstream of Station 52+00 to the LAFB boundary, was completed by the end of 1998 and willbe followed by long-term monitoring to assess the effectiveness of the remediation process.22


Figure 3. Location of OU 13 Study Areas

The SCF is an oil-water separator located on the western bank of the lower end of the FLDD andupstream of the FLDD wetland. SCF sediment "hot-spots" were excavated and the removedsediment properly disposed of during OU13 remediation. Further, the SCF is within a chain-linkfence and secured by a locked gate. Potential human carcinogenic risks are less than the MEDEPcancer guidance value, and noncarcinogenic risks are also less than USEPA and MEDEPguidelines. Therefore, the Spill Containment Facility poses no apparent public health hazard.

The East Branch of Greenlaw Brook (EBGB) begins in a wetland south of the Fuels Tank Farm,flowing westerly 2,500 feet to its confluence with the FLDD Wetland drainage (Figure 3). TheEBGB continues westerly, combining with the WBGB and then merging with the LittleMadawaska River. A total of 29 IRP sites are located near the EBGB, and several are known tohave contributed contaminants, including the Fuels Tank Farm, Base Laundry, RefuelingMaintenance Shop Area, and Coal Storage Pile/Fly Ash Area. The EBGB has also been impactedby contaminants flowing downstream from the flightline area via the FLDD and FLDD Wetland. Primary contaminants in the EBGB include polyaromatic hydrocarbons (PAHs), total petroleumhydrocarbons, chlorinated pesticides (including DDT metabolites and chlordane), PCBs, andlead, among other inorganics. Even so, "...potential human health recreational carcinogenic risksassociated with recreational exposure to surface soil, sediment, and surface water in this studyarea are within or below the USEPA carcinogenic risk range".23 Carcinogenic risks were also ator below the 10-5 MEDEP acceptable risk value except for RME "reasonable maximumexposure" sediment values at the EBGB and at the Ditch G12 PCB hot spot. An RME sedimentvalue at the hot spot also provides the only noncarcinogenic risk value above acceptable risk. These hot spots have been or are being addressed by excavation and removal of sediment and soilfrom the EBGB and Ditches G11 and G12. AFBCA contractors will take sediment, soil, and fishsamples and perform chemical and biological assays to evaluate the effectiveness of theseremovals.

The WBGB begins in a wetland north of the Flight Line Area and about 750 feet west of the baseboundary (Figure 3). The WBGB flows south onto base property, passes west of the Quarry andNose Dock area, and forms Malabeam Lake. Upon leaving the lake the watercourse forms andthen exits Chapman Pit Pond. About 3.4 miles from its source the WBGB merges with theEBGB. The WBGB Study Area contains five IRP sites, including the Quarry, the Nose DockArea, the Base Exchange Service Station, Landfill 1, and the Chapman Pit Disposal Area. GreenPond, beaver ponds, and several drainage ditches and wetlands are also within this study area. Primary contaminants detected in the WBGB Study Area were PAHs, total petroleumhydrocarbons, and metals such as cadmium, lead, manganese, silver, barium, and zinc. However,potential human health carcinogenic risks in this study area, associated with exposure tosediment, surface water, and surface soil, are at or below the cancer risk guidance value of 10-5. Average concentrations for noncarcinogenic effects of contaminants resulted in risks that areacceptable by USEPA and MEDEP guidelines.24 Exposure to surface water, sediment, and soils along the WBGB poses no apparent public health hazard to persons wading or playing.

The Little Madawaska River (LMR) flows south from the dam forming the MadawaskaReservoir and follows a course about 1.5 miles west of the LAFB boundary (Figures 2 and 3). Itstributaries include Wolverton, Brandy, and Greenlaw Brooks. The LMR joins the AroostookRiver a few miles south and east of the city of Caribou. Greenlaw Brook is the primary pathwaycarrying base-related contaminants toward the LMR. However, chemical analysis of predesignand OU13 Remedial Investigation samples of Greenlaw Brook sediments west of the culvertplunge pool under Sawyer Road showed concentrations of PCBs to be below the remediationgoals of 1 mg/kg for stream sediments and 5 mg/kg for sediments or soil in the floodplain.6 Potential current and future carcinogenic and noncarcinogenic risks for surface water andsediment in the LMR are well within the USEPA and MEDEP guidelines for all wading andswimming scenarios used in risk calculations. Risk calculations and values chosen for risk-related parameters are shown in Appendix W of Reference 15. Values chosen for parameters inthe risk equations are conservative (protective of public health) and are acceptable to ATSDR. The impact of future groundwater discharge on surface water contaminant concentrations wasmodeled; the impact of such discharge on future surface-water risks is negligible.25

Butterfield Brook (BB) flows south onto the eastern side of LAFB and into East Loring Lake, a 40-acre impoundment surrounded by the Weapons Storage Area (Figure 3). Willard Brook joins BB as the latter flows from East Loring Lake to Durepo Reservoir, an 80-acre, man-made water body just south of the base boundary. The flow from the reservoir is joined by Durepo Stream from the east to form Limestone Stream (LS). LS enters the Aroostook River 10 miles further south. There are a number of Installation Restoration Program (IRP) sites within the BB/LS Study Area that might contribute contaminants to surface water, including the Railroad Maintenance Site, Fire Training Area, Underground Transformer Site, and the 9,000 Debris Area.26, 27 The Underground Transformer Site Wetland required excavation to achieve an acceptably low level of risk.28 However, risk assessment calculations show that recreational exposure to surface soil, sediment, and surface water in this area are within USEPA and MEDEP guidelines for both cancer and noncancer risk.29 These surface-water bodies pose no apparent public health hazard to persons wading or swimming.



Table 3.

No Apparent Public Health Hazard Situation: Wading and Swimming in On-Site Waterways
PATHWAY NAME CONTAMINANTS EXPOSURE PATHWAYS ELEMENTS TIME COMMENTS
SOURCE ENVIRONMENTAL MEDIA POINT OF EXPOSURE ROUTE OF EXPOSURE POTENTIALLY EXPOSED POPULATION
Surface Water and Sediments in On-site Waterways PCBs, pesticides, PAHs, metals

Releases of hazardous substances to soils, surface water, and groundwater from flight operations and from transformer leaks and other PCB spills and disposal on base

Sediment and surface water

Skin contact and incidental ingestion from wading and swimming

Dermal contact and ingestion.

Potentially Exposed:
Child and adult swimmers and waders.

Current
Future
Most areas present no current public health hazard. Remedial excavation of selected sections of the FLDD/FLDD Wetland and the East Branch of Greenlaw Brook is designed to mitigate risks. Future sampling will provide data to evaluate remaining risk.

PCBs - Polychlorinated Biphenyls
PAHs - Polycyclic Aromatic Hydrocarbons
FLDD - Flight Line Drainage Ditch

Conclusions and Public Health Action Plan: Wading and Swimming in On-Site Waterways

Conclusions:

  1. Wolverton Brook, Brandy Brook, the Spill Containment Facility, the West Branch of Greenlaw Brook and associated impoundments, the Little Madawaska River, and the Butterfield Brook/Limestone Stream drainage system pose no apparent public health hazard to persons wading or swimming.

  2. The FLDD; the FLDD Wetland; the EBGB; Ditches G11 and G12; and the Underground Transformer Site have contained water, sediment, or soil with contaminants present at concentrations of concern. However, these areas represented low short-term risk, and remediation was finished by the end of 1998.

Actions in Progress:

  1. Sediment and soil are being excavated and removed by AFBCA contractors from the FLDD; the FLDD Wetland; the EBGB; Ditches G11 and G12; and the Underground Transformer Site as necessary to lower contaminant levels. The removal actions are guided by analytical results and are being accomplished during the summers of 1997 and 1998.

Planned Actions:

  1. AFBCA contractors will conduct long-term environmental monitoring, to include chemical, physical, and biological testing, to gauge effectiveness of the remediation process. AFBCA will submit a draft of the monitoring program to the USEPA and MEDEP for review and approval prior to implementation.

Recommendations:

  1. ATSDR requests that AFBCA forward the post-remediation analytical results for surface water, sediment, and soil from the FLDD, FLDD Wetland, and EBGB to ATSDR for review.

  2. ATSDR requests that AFBCA forward the long-term environmental monitoring plan for OU13 to ATSDR for review at the same time that it is submitted to USEPA and MEDEP.

II. NO PUBLIC HEALTH HAZARD

ATSDR concluded that three situations associated with the Loring AFB installation pose nopublic health hazard: 1) future land use by new occupants; 2) possible migration of on-basecontaminants to Limestone Stream to yield concentrations in water of public health concern, and 3) volatile contaminants in the air at the Loring installation.

A. Possible Hazards Associated with Future Use of Former Loring Air Force Base Property Parcels by New Occupants, Prevention Needed

1. Previously Addressed Specific Case: The ATSDR health consultation for LAFB published inJanuary of 1997 found that there was no health-related reason that Parcels B and B-1 to B-7should not be transferred to the U. S. Department of Labor for use as a contractor-operated JobCorps Training Center.19

2. Specific Current Case: Transfer of Parcels E and E-1 for for recreational use under management by the U. S. Fish and Wildlife Service (Figure 4).

The parcels (E and E-1) proposed for transfer to the United States Fish and Wildlife Service(USFWS) are largely forest and grassland; a number of buildings and IRP sites are also included. Parcel E is on the eastern side of the base and includes the Fire Training Area, UndergroundTransformer Site, Explosives Ordnance Discharge (EOD) Range, and former Weapons StorageArea. Parcel E-1 is on the western side of the base and contains Landfills 1, 2, and 3. USFWSadministrators envision use of the property for hunting, fishing, hiking, mountain biking, autotouring past wildlife habitats, and wintertime cross country skiing.30 Activities would all bedaytime events with no overnight camping. The parcels would, insofar as possible, be returned to a natural state, with many of the existing buildings and fences removed over time.

There is the potential for physical hazards from equipment and materials left in the bunkers of the former Weapons Storage Area and razor wire atop the surrounding fences. The EOD Range is undergoing sampling and testing to assure acceptably low levels of explosives or munitions residues in soil. The EOD and ten other sites will be "safed", which entails the removal of any live munitions that may have been left behind following munitions practice activities conducted when LAFB was an active base. ATSDR supports planned stipulations in transfer documents that, although these areas are considered safe for recreational uses, incompatible uses, such as construction and digging, will not be allowed. It is ATSDR's understanding that all drinking water wells and monitoring wells for which a future need is not identified are to be sealed and abandoned according to State of Maine standards prior to Air Force transfer of Parcels E and E-1 to USFWS. Also, asbestos in buildings on the parcels is to be removed and properly disposed. If the asbestos is not removed prior to transfer of the parcels, the Decision Document should identify and define this environmental issue so that it may be addressed by the new owners.

Conclusion and Public Health Action Plan: Future Use of Parcels E and E-1 for Recreational Purposes under Management by the U. S. Fish and Wildlife Service (USFWS)

Conclusion:

Contaminants are not present at levels of concern in surface water, sediment, soil, or air on Parcels E and E-1; the concentrations present pose no public health hazard.

Actions in Progress:

The Explosives Ordnance Discharge (EOD) Range is undergoing remediation to assure that explosives or munitions residues are present at or will be reduced to acceptable levels, and that the EOD and ten similar areas will be cleared of any remaining, intact explosives or munitions.

Planned Actions:

  1. Seal and abandon unneeded wells on Parcels E and E-1 according to State of Maine standards prior to property transfer.

  2. Include groundwater use restrictions in all property transfer documents to prevent drilling of water wells in contaminated aquifers.

Recommendations:

  1. AFBCA should remove physical hazards associated with the bunkers within the Former Weapons Storage Area, including equipment and materials remaining in these structures and any razor wire and concertina wire associated with fencing around this area, or, alternatively, disclose the presence of these potential hazards to safe recreational use in the property transfer documentation.

  2. AFBCA should remove and dispose of any asbestos in buildings on Parcels E and E-1 (and other parcels for transfer) or, alternatively, disclose all available information on the existence, extent, and condition of asbestos containing material (ACM) in the appropriate transfer document.

  3. AFBCA should stipulate in explosive safety certification documents that, although the "safed" areas are considered safe for recreational uses, incompatible uses such as construction and digging will not be permitted.

  4. AFBCA should provide the Final version of the transfer documents for Parcels E and E-1 (and other parcels for transfer) to ATSDR for review so that responsibilities of the transferor and transferee to address remaining environmental issues may be identified, and ATSDR can assess whether any of the proposed uses of the property suggest a possible public health hazard.

Figure 4. Main Base Property and Off-Site Parcel IV Limestone Receiver Site - Disposal Parcelization

Levels of contaminants in surface water and sediments of Parcels E and E-1 are low and pose nohazard to persons engaged in recreational pursuits, as shown in Section IC. Fish caught in BBand East Loring Lake contain low levels of DDT and two related compounds that represent nopublic health hazard at expected rates of fish consumption, as illustrated in Section IA andsupported by calculations in Appendix C. The DDT compounds are thought to be due towidespread spraying of DDT for agricultural pest control and not associated with LAFBactivities. Fish caught from surface-water bodies within Parcel E-1 are covered by the MDHSadvisory. Section IIC (below) demonstrates that air quality basewide represents no public healthhazard. Air quality is not an issue on Parcels E and E-1.

3. General Case: Transfer of remaining parcels by deed to new organizations for proposed uses as defined and stipulated in the Record of Decision for the Disposal of Loring AFB, Maine, April 1996.

An Environmental Baseline Survey (EBS) was completed for Loring in 1993. This documentassesses the environmental condition of any property to be acquired, transferred, leased, or soldfor reuse at a former military base. Subsequent updates called Supplemental EBS (SEBS) reportshave been completed for each parcel as it is leased or transferred. An SEBS supports thepreparation of a Finding of Suitability to Lease (FOSL) prior to lease execution and a Finding ofSuitability to Transfer (FOST) before deed conveyance to organizations other than a federalagency. When a transfer is to be effected to an arm of the federal government, the suitabilityinstrument is called a Decision Document. FOSLs, FOSTs, and Decision Documents mustsubstantiate the nature, magnitude and extent of any environmental contamination for a parcel. They assess any health and safety risks on a property to be leased or transferred and stateappropriate restrictions and notifications for the property.

B. Possible Migration of On-Base Contaminants to Limestone Stream to Yield Concentrations in the Limestone Water Supply of Public Health Concern.

Limestone Stream serves as an alternative source of raw water for the Limestone Water District,which supplies potable water to the city of Limestone, Maine. Concerns were expressed in thepast by a former employee at Loring Air Force Base (LAFB), that contamination on the easternside of the base might be migrating to LS and could affect water quality.31

Butterfield Brook (BB) originates north of LAFB and flows southeasterly onto the installation. Willard Brook, a tributary, also originates off-base and joins Butterfield Brook on the LAFBproperty. BB is dammed to form 40-acre East Loring Lake within the Weapons Storage Area,and then flows southeasterly to join Durepo Brook in forming Durepo Reservoir just to the eastof the LAFB boundary (Figure 3). LS, formed by the outflow of Durepo Reservoir, flows souththrough the city of Limestone to its confluence with the Aroostook River, ten miles from DurepoReservoir. A portion of the stream flow is diverted as needed to provide Limestone with a backup supply of potable water.

All surface water samples from the BB/LS Study Area, including a "hot spot" sample, gave totalcarcinogenic risks and total noncarcinogenic risks below MEDEP guidance values and within theUSEPA range of acceptable risk. Analysis of surface water in the Durepo Reservoir detected nocarcinogenic chemicals of potential concern.32 The noncarcinogenic risk was three orders ofmagnitude below the threshold of acceptable risk. Since the Durepo Reservoir is located off-site at the downstream end of Butterfield Brook, it is clear that this watershed is not contributing measurable contamination to Limestone Stream by the surface-water pathway.

A final consideration is whether contaminants might be entering LS via the groundwaterpathway. Ten groundwater flow fields (FFs) are identified in the LAFB OU12 RemedialInvestigation Report33, of which two (FF 10 and FF 5) could influence LS. FF 10 is the largerand more northerly of the two flow fields. The Fire Training Area (FTA) and the UndergroundTransformer Site (UTS) are potential contributors of contaminants to FF 10 groundwater. Vinylchloride, benzene, arsenic, TCE, CCl4, phthalates, manganese and iron were detected at lowconcentrations in various combinations at several sampling sites. Risk assessments thatevaluated the groundwater as if it were drinking water yielded total carcinogenic risks of around1 x 10-4 and noncarcinogenic risk hazard indices of about 15, where a hazard index of one or lessindicates no health effect. The values of 1 x 10-4 and 15 are somewhat conservative since thevinyl chloride seemed to be an artifact contributed by the WestbayTM monitoring wells and thephthalates an artifact due to laboratory contamination. Although contributing to risk, themanganese and iron are likely not related to LAFB activities. The most important conclusion ofthe basewide groundwater flow model for LAFB is that shallow groundwater on the installationdischarges primarily to local streams and surface waters.34 Specifically "East Loring Lake andthe BB drainage area (includes saturated overburden) are the discharge areas for bedrock andoverburden groundwater flowing beneath both sites."35 and " The highest concentrations ofcontaminants are located in proximity to the source area; contaminant concentrations diminishdowngradient from the source area and downward within the aquifer."35 The discharge ofgroundwater into East Loring Lake and BB has not resulted in measurable concentrations ofchemicals of concern in Durepo Reservoir, as seen from the surface water analyses alluded toabove. The groundwater flow patterns do not produce contamination in deep groundwater thatcould adversely impact either Limestone Stream or the Aroostook River.

FF 5 is smaller than FF 10 and is located at the Railroad Maintenance Site. When thegroundwater at FF 5 was evaluated for human risk as if it were to be used for drinking water, therisk drivers were vinyl chloride and bis(2-ethylhexyl phthalate), yielding risks in the 1 x 10-5 range. Circumstances suggested strongly that the vinyl chloride result was an artifact due to plastic usedin the WestbayTM monitoring well. This compound was not detected in any of the other wells;associated chlorinated parent compounds PCE and TCE were not detected in any wells at thesite. The phthalate compound is often found as a laboratory artifact, due to its ubiquity as aplasticizer. If these two compounds are ignored in the risk calculation, the risk of drinking thesampled FF 5 groundwater is less than 1 x 10-6. LS, which flows to within about 1 mile from FF5, is the likely discharge area for groundwater from FF 5; however, there appears to be nosignificant contamination of FF 5 groundwater in terms of human health. If contaminationexisted, concentrations would be diminished greatly before reaching LS. There is a smalltributary entering Noyes Lake, south of Noyes Mill Road and west of LS. Analysis of a watersample from this brook in March of 1993 showed no contaminants of concern at levels thatwould pose a public health hazard.36 Contaminants on base do not migrate to Limestone Streamto yield concentrations of public health concern in the Limestone Water District water supply.

C. Air Quality on Base

ATSDR prepared a health consultation for LAFB in January 1997 to address several possibleexposure pathways, including the air pathway in the vicinity of the FLDD.19 ATSDR concludedin this consultation that the exceedingly low levels of airborne contaminants measured at variouspoints near the FLDD and on adjacent Job Corps campus parcels posed no public health hazardto Job Corps students or employees. The other areas of the installation are further from theFLDD and thus even less impacted than the Job Corps Parcels. Arguments showing thatpotential air-emission sources due to remediation activity and identified in the health consultationdo not represent a public health hazard may be generalized to include all areas of the installation. No other significant sources of air emissions have been identified on base. The low contaminantconcentrations in air on the Loring installation pose no public health hazard.

Data included in Reference 19, the January 1997 ATSDR Health Consultation for LAFB,provides perspective on past exposures at the base to contaminants in air. The 1993 data in theAir Monitoring Technical Memorandum for Loring AFB37 show an average concentration forthree 8-hour-long monitoring events of 1.82 ppbv for benzene at the FLDD headwall "hotspot". This value, representative of the worst-case, localized concentration of this risk-drivingcompound during a time when LAFB was in operation, is comparable to the 1.80 ppbv dailymedian benzene concentration expected as background in suburban areas of the United States38. Samples taken upwind from the FLDD averaged 0.22 ppbv benzene while downwind samplesregistered 0.32 ppbv, both values less than the 0.47 ppbv background level characteristic of ruralAmerica38. The low contaminant concentrations in air believed to have existed at LAFB in thepast represented no public health hazard.


COMMUNITY HEALTH CONCERNS EVALUATION AND
HEALTH OUTCOME DATA

1. At the time of the first ATSDR site visit in 1991 some members of the communityexpressed concerns that levels of radioactivity existed at Loring that could pose a danger topersons.

Radioactivity associated with storage and maintenance of strategic and conventional weapons atLoring was confined to Operable Unit 1, the Low-Level Radioactive Waste Disposal Sites. These seven sites, designated Areas A through G, were located in the former Weapons StorageArea of Loring Air Force Base. The seven sites include two former low-level radioactive wastedisposal trenches and five underground storage tanks (USTs) for low-level radioactive liquidwaste. The five radiological USTs were removed in 1994, as were the contents of the two wastetrenches. Tests showed no leaking of the tanks and that no significant radioactivity remainedafter exhumation of the contents of the trenches. All radioactive waste was disposed of off site. Any remaining low levels of radioactivity at Site 1 pose no public health hazard to persons,including those who might visit the OU1 sites.

2. Members of the community asked if it was safe to consume fish from waters on base andoff-base water bodies into which they flowed.

As discussed in Section IA of this report, MEDEP, MDHS, and the Air Force, in consultationwith USEPA, agreed that a catch-and-release policy with a recommendation of no consumptionwas appropriate for the Little Madawaska River and its tributaries, including those on formerLAFB property, south of the reservoir dam to the point where the LMR passes under GrimesRoad. The waters affected are shown in Figure 2 and include streams and impoundments onformer LAFB property. Other waters in the area are not affected by the advisory. Theconcentrations of PCBs in fish necessitate the advisory to protect public health. With removal ofmost of the PCBs in EBGB sediments by remedial excavation, as existing fish grow old and dienew generations will be exposed to greatly reduced concentrations, and PCB levels in fish willdiminish. The Base Cleanup Team estimates that the restrictions of the fishing advisory will bereduced and possibly lifted over the next five to ten years.

3. Is on-base contamination migrating to Limestone Stream (an alternate source of publicwater for Limestone Water and Sewer District)? If so are concentrations of contaminantshigh enough to affect the health of persons drinking the water?

Possible surface-water and groundwater pathways for transport of contaminants to LimestoneStream are considered in section IIB of this document. Surface-water and groundwater analysis, together with information on groundwater modeling, show that contaminants on base do notmigrate to Limestone Stream to yield concentrations of public health concern in the LimestoneWater District water supply.

4. A citizen mentioned that it seemed to him a number of persons he knew of onMadawaska Road had cancer. He wondered whether these cancers could be associated inany way with contaminants that had originated on base, particularly in Landfills 2 and 3.

There is no evidence that contaminants from these landfills have migrated the several miles tothe area of Madawaska Road. Monitoring wells are located at close intervals in a "picket fence"array to be able to detect and characterize any off-site migration of contaminants in groundwater. A private water well near the LAFB boundary proximate to Landfill 2 is monitored annually andhas shown no evidence of contamination. Long-term monitoring of groundwater will continue forat least the next 30 years. No other pathways could transport contaminants from the base to thehouses in significant concentrations.

People have strong fears about cancers caused by environmental exposures. It has beenestimated that only about 2% of human cancer deaths are attributed to environmental pollution.39The presence of environmental contamination in a community does not necessarily mean thatpeople are coming into contact with sufficient quantities of hazardous materials to cause disease. Again, we emphasize that it is our opinion that no contaminants from LAFB have migrated to thearea of Madawaska Road to make exposure of persons possible.

5. The Environmental Health Director for the Aroostook Band of Micmacs expressedconcerns about future exposures of tribal members to possible hazards, including chemicalcontamination, associated with future use of former Loring Air Force Base parcels slatedfor transfer to the Micmac Tribe.40 More specifically, he was concerned that certain plantor animal species might uptake or bioaccumulate contaminants at the site to hazardouslevels. He asked whether following Tribal cultural practices and food preferences on theseparcels (Parcels D and D-1) might pose a public health hazard.

ATSDR is sensitive to the concerns expressed by the Micmac Environmental Health Director andwill work with his office and other Micmac authorities to develop a health consultation toidentify and evaluate potential exposure pathways. Available environmental data will provideinformation on identity and concentration of contaminants in soils on the parcels. A search of theliterature will yield information from existing studies of bioaccumulation from soil of variouscontaminants in plant and animal species. For food plants and animals, the major route of humanexposure is ingestion. Inhalation of smoke from burning plant materials in cultural and spiritualactivities is another route. Dermal contact can also occur. Detailed information on Micmaccustoms and food preferences can guide the identification of possible specific exposurepathways. These considerations, combined with other information including the geology of theAroostook County region, should permit evaluation of risks inherent in the specific pathways.



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