PUBLIC HEALTH ASSESSMENT
HANSCOM FIELD/HANSCOM AIR FORCE BASE
BEDFORD, MIDDLESEX COUNTY, MASSACHUSETTS
Figure 2. IRP Sites at HF/HAFB
Figure 3. Demographics Within a One-Mile Radius of HF/HAFB
Table 1. Exposure Pathways evaluated at Hanscom Field/Hanscom Air Force Base
| Exposure Situation | Time Frame | Exposure Yes/No |
Hazard | Actions Taken/Planned | Recommendations | Public Health Evaluation |
| 1. Have past HAFB activities impacted off-site and community water supplies? | ||||||
| The groundwater plumes are primarily located within site
boundaries, but some VOC contamination, at relatively low levels, has extended
beyond the site's northern boundary into the Bedford Forest. However, community
members living near HF/HAFB and base residents do not use groundwater beneath
or immediately downgradient of the site, therefore no exposures are occurring
to site-related groundwater contamination.
Possible Contaminants: VOCs including TCE, cis-1,2-DCE, and vinyl chloride from numerous plumes in OU-1. |
Past Current Future |
No No No |
No No No |
Actions - HAFB has characterized and delineated boundaries of plumes across the site through numerous IRP investigations beginning in 1983. - In 1991, HAFB began extracting and treating groundwater contamination in areas of OU-1. - HAFB is at various stages of plume remediation/planning for other plumes across the site. - HAFB monitors off-site wells and boundary wells along the northern border. |
Recommendations ATSDR concurs with the continued off-site groundwater monitoring to ensure that contaminants are not migrating off site in the directions of private water supplies. ATSDR also agrees with HAFB's decision to implement and enforce institutional controls to ensure that no new drinking water or irrigation wells are installed in locations within contaminant plumes. |
ATSDR has determined that no groundwater drinking wells
are located within plume areas, and the groundwater beneath the site is
not used as a water supply. Thus, the groundwater pathway is incomplete.
|
| 2. Could people be harmed by exposure to former landfill areas on and around the site? | ||||||
| 2a. Installation Restoration Program (IRP) Site 4 | ||||||
| Workers and residents using the current ball field located
at the former IRP Site 4 Landfill could come in contact with buried hazardous
substances.
Possible Contaminants: VOCs, SVOCs, and metals.
|
Past Current Future |
Unknown Yes Yes |
Unknown No No |
Actions - HAFB discovered a leachate problem in 1974, soon after the landfill was closed, followed by erosion problems identified in 1977. - In 1988, HAFB capped the landfill with a low permeability cap, covered it with grass, bermed around the edges, and converted it to grassed open space, part of which is used as a ball field. - Additional risk assessments and long-term monitoring of soil, groundwater, and surrounding surface water (1989-1996) determined that no further action was needed. -The area is currently fenced to prohibit motor-vehicle traffic, but access by foot is possible. The area is inspected quarterly for cap maintenance needs. |
Recommendations ATSDR concurs with HAFB's decision to maintain the cap and conduct inspections at the IRP Site to ensure continued protection of public health. |
ATSDR has reviewed surface soil data from IRP Site 4 investigations and determined that no contaminants are present in concentrations that would cause adverse health effects for current and future users of the site. However, due to lack of sampling data, exposures prior to remediation are unknown. |
| 2b. IRP Site 6 Former Filter Bed Area | ||||||
| Workers and residents frequenting areas near IRP Site
6 could come in contact with waste from the former filter bed area and former
landfills in surface soil and surrounding surface water.
Possible Contaminants: VOCs, SVOCS (including PAHs), pesticides, and metals. |
Past Current Future |
Unknown No No |
Unknown No No |
Actions - HAFB conducted remedial investigations of IRP Site 6 soil, groundwater, and surrounding surface water in 1993, 1996, and 1998. - In 2001, HAFB removed "hotspots" of contamination within the surrounding wetlands and installed a permeable cap on the landfill areas. - In October 2002, HAFB began long-term monitoring of the area and put in place institutional controls to prevent digging and dumping and control access. The area is currently fenced with locked gates and posted with "No Digging, No Dumping, Per Order of the Installation Commander" signs. |
Recommendations ATSDR concurs with HAFB's decision to continue to maintain the cap over the area, conduct inspections, and enforce institutional controls. |
ATSDR has reviewed surface soil data from IRP Site 6 investigations and determined that current institutional controls, including a fence and posted signs, prevent public access to this area. Contamination that spilled over the site boundary has been removed. Consequently there is no current or future exposure at this site, however, due to lack of sampling data, potential exposure prior to removal is unknown. |
| 2c. IRP Site 8 Scott Circle Landfill | ||||||
| Potential contact with buried substances in the landfill
by workers and residents, including children frequenting IRP Site 8. Note:
The daycare center is fenced; therefore, children attending do not have
access to the site. However, older children living in the nearby housing
areas and walking to/from school do have access.
Possible Contaminants: Petroleum hydrocarbons and metals, particularly lead. |
Past Current Future |
Unknown Yes Yes |
Unknown No No |
Actions - HAFB conducted soil, groundwater, and surface water sampling of IRP Site 8 from 1986 to 1990. - HAFB capped and covered exposed soil with clean soil and grass in October 1991. |
Recommendations ATSDR concurs with the continued maintenance of the cap over the area. |
ATSDR has evaluated surface soil data from IRP Site 8 investigations and determined that current and future contaminant levels are not expected to cause adverse health effects in the concentrations and distribution detected. Past exposure is unknown due to lack of sampling data. |
| 3. Are recreational users of the Shawsheen River exposed to harmful levels of contaminants in surface water or sediment? | ||||||
| Recreational users of the Shawsheen River adjacent to
and downstream of HF/HAFB may be exposed to surface water and sediment contamination
through wading, fishing, canoeing, and incidental ingestion.
Potential Contaminants: VOCs, SVOCs, pesticides, and metals. |
Past Current Future |
Yes Yes Yes |
No No No |
Actions - HAFB has sampled portions of the surface water and sediment in the Shawsheen River and surrounding wetlands during various remedial investigations of the sites along the river. |
Recommendations Because on-site groundwater plumes can discharge to and potentially impact surface water quality, ATSDR concurs with the USAF's continued monitoring of the groundwater quality to assure that levels do not increase to the point that contamination could reach the Shawsheen River or surrounding wetlands at levels that could present a public health hazard.
|
Based on available surface water and sampling data from
IRP Sites 4, 6, 8, 21, and OU-1, contaminants present in surface water and
sediment are not expected to cause adverse health effects based on conservative,
recreational use exposure estimates.
|
Sources: HAFB 2002a, 2002b
Key:
ATSDR = Agency for Toxic Substances and Disease Registry
DCE = dichloroethylene
HAFB = Hanscom Air Force Base
HF/HAFB = Hanscom Field/Hanscom Air Force Base
IRP = Installation Restoration Program
OU = operable unit
PAH = polycyclic aromatic hydrocarbon
SVOC = semi-volatile organic compound
TCE = trichloroethylene
VOC = volatile organic compound
| OU # | Site # | Site Name | Documents Reviewed Related to Site | Investigated Further? | Section of PHA |
| 1 | 1 2 3 5 19 20 |
Fire Training Area Paint Waste Disposal Area Jet Fuel Residue/Tank Sludge Disposal Area Fire Training Area I Suspected Dump Site Suspected Fire Training Area |
HAFB 2002a; HAFB 2002b; CH2MHILL 1997a; IT 2002a | Yes | GW |
| 2 | 4 | Sanitary Landfill | HAFB 2002a; HAFB 2002b; CH2MHILL 1996; CH2MHILL 1997b; O'Brien & Gere Engineers, Inc 1996 | Yes | Soil |
| 3 | 6 | Former Filter Bed Area | HAFB 2002a; HAFB 2002b; Metcalf & Eddy 1992; EA Engineering, Science, and technology, Inc. 1998; CH2MHILL 1998; CH2MHILL 1999; IT 2002b; IT 2002c | Yes | Soil |
| 3 | 21 | Unit 1 Petroleum Release Site | HAFB 2002a; HAFB 2002b; Environmental Compliance Services, Inc 1998a; Environmental Compliance Services, Inc 1998b; IT 2002d | Yes | GW, SW/Sed |
| 4 | 7 | Industrial Waste Water Treatment Plant | HAFB 2002a; HAFB 2002b | No | NFA |
| 4 | 8 | Scott Circle Landfill | HAFB 2002a; HAFB 2002b; Metcalf & Eddy 1990; Metcalf & Eddy 1992 | Yes | Soil |
| NA | 9 | Administration Building Jet Fuel Spill | HAFB 2002a; HAFB 2002b | No | NFA |
| NA | 10 | Mercury Spill at Building 1128 | HAFB 2002a; HAFB 2002b | No | NFA |
| NA | 11 | Various Fuel Spills on Runways and Taxiways | HAFB 2002a; HAFB 2002b | No | NFA |
| NA | 12 | AAFES Service Station Gasoline Leak | HAFB 2002a; HAFB 2002b | No | NFA |
| NA | 13 | Motor Pool Gasoline Leak | HAFB 2002a; HAFB 2002b | No | NFA |
| NA | 14 | Multi-site UST Investigation | HAFB 2002a; HAFB 2002b | No | NFA |
| NA | 15 | Multi-site UST Removal | HAFB 2002a; HAFB 2002b | No | NFA |
| NA | 16 | Contamination at Building T-860 | HAFB 2002a; HAFB 2002b | No | NFA |
| NA | 17 | Contamination at Building 1103 | HAFB 2002a; HAFB 2002b | No | NFA |
| NA | 18 | Contamination at Building 1102-C | HAFB 2002a; HAFB 2002b | No | NFA |
| NA | 22 | AAFES Service Station Petroleum Leaks | HAFB 2002a; HAFB 2002b | No | NFA |
Key:
GW = groundwater
NA = not applicable
NFA = no further action
SW/Sed = surface water/sediment
UST = underground storage tank
Table 3. Contaminants Detected Above Comparison
Values in Surface Soil at Sites 4 and 8
| Chemical | Location | Maximum Concentration (ppm) |
CV (ppm) | CV Source | Number of Samples > CV | Number of Samples Analyzed |
| Benzo(a)pyrene | Site 4 | 0.45 | 0.1 | CREG | 1 | 2 |
| Arsenic | Site 4 | 15 J | 0.5 | CREG | 2 | 2 |
| Arsenic | Site 8 | 32 | 0.5 | CREG | 15 | 15 |
Sources: Metcalf & Eddy 1990, 1992; O'Brien & Gere 1996.
Key:
CREG = cancer risk evaluation guide
CV = comparison values
J = estimated quantity
ppm = parts per million
Note: Soil samples from Site 8 were collected "generally less than five-foot depth" (Metcalf & Eddy 1990).
Table 4. Contaminants detected above Comparison
Values in Surface Soil at Site 6
| Chemical | Location | Maximum Concentration (ppm) | CV (ppm) | CV Source |
| Benzo(a)pyrene | Site 6 - Ash Disposal Area | 23 | 0.1 | CREG |
| Benzo(b)fluoranthene | Site 6 - Ash Disposal Area | 24 | 3.9 | RBC-C |
| Benzo(a)anthracene | Site 6 - Ash Disposal Area | 31 | 3.9 | RBC-C |
| Dibenzo(a,h)anthracene | Site 6 - Ash Disposal Area | 2.6 | 0.39 | RBC-C |
| Indeno(1,2,3-cd)pyrene | Site 6 - Ash Disposal Area | 9.9 | 3.9 | RBC-C |
| Arsenic | Site 6 | 11.1 | 0.5 | CREG |
| Lead | Site 6 | 470 | 400 | EPA action level |
Sources: EA 1998; IT 2002b
Key:
CREG = cancer risk evaluation guide
CV = comparison values
EPA = U.S. EPA
ppm = parts per million
RBC-C = risk-based concentration, cancer (industrial scenario)
Table 5. Contaminants Detected Above Comparison
Values in Shawsheen River Surface Water
| Chemical | Maximum Concentration (ppb) | CV (ppb) | CV Source | Number of Samples > CV | Number of Samples Analyzed |
| Chloromethane | 41 | 3 | LTHA | 6 | 18 |
| Vinyl chloride | 0.11 F | 0.03 | CREG | 1 | 18 |
| Aldrin | 0.045 P | 0.002 | CREG | 2 | 6 |
| Heptachlorepoxide | 0.038 | 0.004 | CREG | 1 | 6 |
| Arsenic | 5.5 B | 0.02 | CREG | 4 | 12 |
| Manganese | 780 | 500 | RMEG-child | 5 | 12 |
Sources: EA 1998; Metcalf & Eddy 1992; IT 2002d.
Key:
B = result between instrument detection limits (IDL) and contract
required detection limits (CRDL).
CREG = cancer risk evaluation guide
CV = comparison value
F = result between method detection limit (MDL) and recovery limit (RL)
LTHA = lifetime health advisory
P = lower gas chromatography (GC) column value
ppb = parts per billion
RMEG-child = reference media evaluation guide - value for a child
Note: The detection limit for arsenic was 2 ppb, above the CV of 0.02 ppb. For the three samples that were not above CV, they were below the detection limit, so they may or may not have been above CV.
Table 6. Contaminants Detected Above Comparison
Values in Wetland Surface Water Surrounding Operable Unit 1
| Chemical | Maximum Concentration (ppb) |
Date of Maximum | CV (ppb) | CV Source | Number of Samples > CV |
Number of Samples Analyzed |
| Vinyl chloride | 19 | March-86 | 0.03 | CREG | 7 | 37 |
| Methylene chloride | 9 | October-87 | 5 | CREG | 1 | 33 |
| 1,2-Dichloroethene (total) | 130 | March-86 | 55 | RBC-N | 3 | 37 |
| 1,2-Dichloroethane | 4.9 J | October-87 | 0.4 | CREG | 1 | 37 |
| Trichloroethene | 100 | March-86 | 5 | MCL | 14 | 37 |
| Benzene | 1.5 J | September-88 | 0.6 | CREG | 1 | 23 |
| Lead | 130 | May-98 | 15 | EPA action level | 4 | 10 |
Source: IT 2002a
Key:
CREG = cancer risk evaluation guide
CV = comparison value
EPA = U.S. Environmental Protection Agency
J = estimated quantity
MCL = maximum contaminant level
ppb = parts per billion
RBC-N = risk-based concentration, noncancer
Table 7. Contaminants Detected Above Comparison
Values in Elm Brook and Wetland Surface Water Surrounding IRP Site 4
| Chemical | Maximum Concentration (ppb) | CV (ppb) | CV Source | Number of Samples > CV | Number of Samples Analyzed |
| Methylene chloride | 14 B | 5 | CREG | 6 | 23 |
| Arsenic | 14.9 | 0.02 | CREG | 14 | 14 |
| Iron | 27,900 | 11,000 | RBC-N | 1 | 27 |
| Manganese | 1,630 | 500 | RMEG-child | 4 | 14 |
Sources: CH2MHILL 1996; O-Brien & Gere 1996; Environmental Resources Management, Inc. 1992.
Key:
B = associated with laboratory blank contamination
CREG = cancer risk evaluation guide
CV = comparison value
ppb = parts per billion
RBC-N = risk-based concentration, noncancer
RMEG-child = reference media evaluation guide-value for a child
Table 8. Contaminant Detected Above Comparison
Values in Wetland Surface Water Surrounding Sites 6 and 21
| Chemical | Maximum Concentration (ppb) |
CV (ppb) |
CV Source | Number of Samples > CV | Number of Samples Analyzed |
| Benzene | 1 | 0.6 | CREG | 2 | 9 |
| Chloromethane | 27 | 3 | LTHA | 2 | 7 |
| Benzo(a)pyrene | 0.059 | 0.005 | CREG | 1 | 1 |
| Heptachlorepoxide | 0.092 P | 0.004 | CREG | 1 | 5 |
| Arsenic | 108 | 0.02 | CREG | 3 | 10 |
| Cadmium | 5.8 | 2 | EMEG-chr-child | 1 | 10 |
| Iron | 175,000 | 11,000 | RBC-N | 2 | 7 |
| Lead | 28.1 | 15 | EPA action level | 2 | 8 |
| Manganese | 1,530 | 500 | RMEG-child | 4 | 8 |
| Vanadium | 202 | 30 | EMEG-int-child | 1 | 7 |
Sources: Dynamac Corporation 1988; EA Engineering Science and Technology 1998; HAFB 2000; Metcalf & Eddy 1992
Key:
CREG = cancer risk evaluation guide
CV = comparison value
EMEG-chr-child = chronic environmental media evaluation guide, value for a child
EMEG-int-child = intermediate environmental media evaluation guide, value for
a child
EPA = U.S. Environmental Protection Agency
LTHA = lifetime health advisory
P = lower gas chromatography (GC) column value
ppb = parts per billion
RBC-N = risk-based concentration, noncancer
RMEG-child = reference media evaluation guide, value for a child
Table 9. Contaminants Detected Above Comparison
Values in Shawsheen River Sediments
| Chemical | Maximum Concentration (ppm) | CV (ppm) | CV Source | Number of Samples > CV | Number of Samples Analyzed |
| Benzo(a)anthracene | 2.2 | 0.87 | RBC-C | 4 | 9 |
| Benzo(b)fluoranthene | 3.4 | 0.87 | RBC-C | 6 | 9 |
| Benzo(a)pyrene | 2.2 | 0.09 | CREG | 9 | 9 |
| Dibenzo[a,h]anthracene | 0.29 | 0.09 | RBC-C | 1 | 4 |
| Indeno[1,2,3-cd]pyrene | 1.2 | 0.87 | RBC-C | 2 | 9 |
| PCB-1260 | 1.3 D | 0.32 | RBC-C | 2 | 8 |
| Arsenic | 36 | 0.5 | CREG | 12 | 12 |
Sources: Dynamac Corporation 1988; EA Engineering Science and Technology 1998; Metcalf & Eddy 1992
Key:
CREG = cancer risk evaluation guide
CV = comparison value
D = analysis conducted at a secondary dilution factor
PCB = polychlorinated biphenyl
ppm = parts per million
RBC-C = risk-based concentration, cancer (residential scenario)
Table 10. Contaminants Detected Above Comparison
Values in Wetland Sediments
| Contaminant | Maximum Concentration (ppm) | CV (ppm) | CV Source | Number of Samples > CV | Number of Samples Analyzed |
| Site 4 - Elm Brook and Surrounding Wetlands | |||||
| Arsenic | 32 J | 0.5 | CREG | 13 | 13 |
| Iron | 52,100 | 23,000 | RBC-N | 4 | 13 |
| Site 6 - Surrounding Wetlands | |||||
| Benzo(a)pyrene | 0.38 | 0.09 | CREG | 3 | 10 |
| Heptachlor epoxide | 0.1 | 0.08 | CREG | 1 | 23 |
| PCB-1248 | 1.9 | 0.32 | RBC-C | 1 | 5 |
| Arsenic | 38.1 | 0.5 | CREG | 7 | 8 |
| Iron | 95,500 | 23,000 | RBC-N | 1 | 7 |
Sources: CH2MHILL 1996, 1997, 1998, 2001; Dynamac 1988; EA Engineering Science and Technology 1998; IT 2002c; Metcalf & Eddy 1992; O-Brien & Gere 1996
Key:
CREG = cancer risk evaluation guide
CV = comparison value
J = estimated quantity
PCB = polychlorinated biphenyl
RBC-C = risk-based concentration, cancer (residential scenario)
RBC-N = risk-based concentration, noncancer (residential scenario)
Table 11. Contaminants Detected Above Comparison
Values in the Hartwell Road Production Wells
| Contaminant | Maximum Concentration (ppb) |
CV (ppb) |
CV Source |
| Benzene | 30 | 0.6 | CREG |
| Trichloroethylene | 33 | 5 | MCL |
| Iron | 31,000 | 300 | Secondary MCL |
Source: CDM 1984c
Key:
CREG = cancer risk evaluation guide
MCL = maximum contaminant level
ppb = parts per billion
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