ATSDR - PHA - South Weymouth Naval Air Station, South Weymouth, Norfolk County, Massachusetts

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ATSDR > Public Health Assessments & Consultations

PUBLIC HEALTH ASSESSMENT

SOUTH WEYMOUTH NAVAL AIR STATION
SOUTH WEYMOUTH, NORFOLK COUNTY, MASSACHUSETTS

APPENDICES

APPENDIX A: Evaluation of Potential Public Health Hazards Associated With the MCP Sites

MCP Site	Site Description/Waste Disposal History	Environmental Monitoring Results	Corrective Activities and Current Status	ATSDR's Evaluation of Public Health Hazards
MCP SITES AT SWNAS
1986 JP-5 spill	On December 13, 1986, a JP-5 fuel storage tank was overfilled by approximately 6,000 gallons. The fuel flowed overland and intercepted a storm drain leading to French's Stream. Oil traveled off site to Rockland and Abington.	Soil: Soil was screened for excavation and removal by headspace measurement of VOC vapors.	Corrective Activities: •The spill was contained as much as possible with sorbent pads and booms. Oil was recovered from surface water with a vacuum truck. • At least 150 cubic yards (cy) of contaminated soil were excavated, stockpiled, and removed. Current Status: • No further remedial action is planned.	Soil: Any health hazards presented by contaminated soil cannot be evaluated due to the lack of sampling data. Any dermal exposure through recreational use was likely to be very limited, however, because the spill occurred in December and grossly contaminated soil was removed soon thereafter. Surface water: French's Stream does not supply drinking water. Any recreational exposure was unlikely because the spill occurred in December.
#3-2621 SWNAS	This site designation refers to the SWNAS listing as a National Priorities List site. The Navy is conducting investigations and remediation under CERCLA.	CERCLA investigations are described in the Evaluation of Environmental Contamination and Potential Exposure Pathways section of this PHA.	CERCLA investigations are described in the Evaluation of Environmental Contamination and Potential Exposure Pathways section of this PHA.	CERCLA investigations are described in the Evaluation of Environmental Contamination and Potential Exposure Pathways section of this PHA.
#3-10239 Small Spill at Bachelor Officers' Quarters (BOQ)	On November 30, 1993, 30 to 35 gallons of No. 2 fuel oil were released from a portable boiler. The release was restricted to the ground surface beneath a mobile trailer used to heat the BOQ.	Soil: Confirmatory soil samples after excavation showed contamination was below MCP cleanup levels.	Corrective Activities: • Approximately 8 cy of soil were removed. Current Status: • The site is now incorporated into the Large Spill MCP Site at the BOQ site (#3-10469).	Soil: The spill occurred beneath a mobile trailer, thereby limiting past exposure to contamination. Contaminated soil was removed. No current or future exposures exist.
#3-10469 Large Spill at BOQ	On January 21, 1994, a fuel line to a 3,000-gallon UST was severed during construction activities and fuel oil leaked out.	Soil: Confirmatory samples indicated contamination was reduced to below MCP cleanup levels, except for inaccessible soil beneath the building foundation. Groundwater: Oil accumulated on the surface of groundwater in the open excavation and in the basement sump of the BOQ. Sampling from 10 monitoring wells did not detect any contaminants.	Corrective Activities: • Site investigation. • Oil and oil-soaked soil were removed. • Immediate Response Action (IRA) Plan required the installation of a groundwater treatment system with effluent going to French's Stream. • UST and 800 cy of contaminated soil were removed and disposed of off site. The area is clean except for contaminated soil beneath the building foundation. • Excavated areas have been backfilled. Current Status: • Navy is preparing an activity use limitation (AUL) for this area under the building. • Response Action Outcome (RAO) is planned for December 1999.	Soil: Past exposures to the public were unlikely due to site access restrictions. Accessible contaminated soil was removed. Present exposure is unlikely because remaining contaminated soil is inaccessible. AUL on the remaining inaccessible contaminated soil will prevent future exposures. Groundwater: No production wells are located in this area, therefore, there were no past or present exposures. The UST and contaminated soil were removed, therefore preventing future exposures.
#3-10628 Building 81 Spill	A 500-gallon UST used for temporary storage of waste oil was removed in 1991. Stained soil was observed by the removal workers. Since 1991, a series of seven investigations have been conducted to define the nature and extent of contamination and remove contaminant sources.	Soil: Over the seven investigations, 34 soil samples were collected. PAHs exceeded comparison values in soil. Groundwater: Over the seven investigation, 51 monitoring wells were installed and sampled. LNAPL and kerosene-type fuel oil were detected in one well. The most recent sampling of 34 wells detected 1,1-dichloroethene, benzene, trichloroethylene, and PCE above comparison values.	Corrective Activities: • UST removed in 1991. • Phase I Limited SI conducted in March 1993. • Immediate Response Action conducted in August 1994. Soil excavated from UST vicinity. • Phase I Initial Site Investigation conducted in March 1995. • Supplemental Phase II field program to delineate PCE completed in July 1997. • Release Abatement Measure (RAM) completed in 1998. Approximately 1,250 cy of soil containing LNAPL was excavated. Current Status: • Ongoing investigations are being conducted to support remedial actions.	Soil: Past exposures to the public were unlikely due to access restrictions. Present and future exposures are unlikely because access is still limited and future remedial activities will likely achieve cleanup goals. Groundwater: No production wells are located in this area, therefore, there were no past or present exposures. Remedial activities should reduce contaminants in groundwater to levels that are protective of human health for any future uses.
#3-10739 Building No. 226 / Tacan Spill	Downstream of the Tacan storm water outfall, a sheen was discovered on French's Stream when approximately 200 gallons of oil were released from an oil/water separator located beneath an airfield tarmac.	Surface Water: Samples were collected to document cleanup actions. Sediment: Collected samples contained residual petroleum hydrocarbons at the outfall. Additional samples were taken within the containment boom.	Corrective Activities: • Oil absorbent booms were deployed across the drainage brook downstream of the outfall and oil was skimmed directly from the water surface to limit contamination. • The Phase I Limited SI of French's Stream in March 1995, concluded that further investigation was required. • Phase II Report submitted in March 1997. • RAO submitted in August 1997. Current Status: • No further remedial action is planned.	Surface Water: Access to the site is restricted and past exposures to the general public were therefore unlikely. Current and future exposures will not pose a public health hazard because remedial activities reduced contaminant concentrations. Sediment: Access to the site is restricted and past exposures to the general public were unlikely. Current and future exposures will not pose a public health hazard because remedial activities reduced contaminant concentrations.
#3-10858 Fuel Tank Farm	The fuel farm was developed in 1951 and used for storage of jet fuels and aviation gasoline until 1994, when three tanks were removed. Two tanks remain.	Soil: Total petroleum hydrocarbons (TPH) were detected at greater than 500 ppm. Groundwater: A 2-inch layer of LNAPL was detected in one well. MCP groundwater reportable concentrations of 50 ppm were also exceeded.	Corrective Activities: • A SI in August 1991 collected surface water and sediment samples in accordance with the IRP. • The Navy conducted a Phase I Limited SI in accordance with the MCP and removed Tanks 1, 4, and 5 and associated contaminated soils. • The Draft Phase IV Report was distributed for public comment in July 1997. • Tanks and 500 cy of contaminated soil was removed. Current Status: • Additional soil removal may be required. • The Navy may propose an AUL at this site. • Project completion expected in January 2000.	Soil: Access was highly restricted and past exposures to the general public were therefore unlikely. Present and future exposures are unlikely because access is still limited and future remedial activities will likely achieve cleanup goals. Groundwater: No production wells are located in this area; therefore, there were no past or current exposures to groundwater. Remedial activities should reduce contaminants in groundwater to levels that are protective of human health for any future uses.
#3-11622 Building 81	The Navy notified the MADEP about a second release of waste oil at this site related to the first release (#3-10628). These two sites are addressed together under #3-10628.	See #3-10628	See #3-10628	See #3-10628
#3-13157 Failed Leak Test at Building 8	Five 25,000-gallon No. 6 fuel oil USTs located adjacent to the Boiler Building were tested in November 1995. Tank 4 was determined to be leaking, based on the presence of tracers in the soil surrounding the tank.	Soil: Three soil borings were sampled during the installation of monitoring wells. Groundwater: Three monitoring wells were constructed as part of the IRA plan.	Corrective Activities: • The Navy filed a Release Notification Form with MADEP in December 1995. • A follow-up IRA Status Report was submitted to MADEP in March 1996. • RAM to remove the UST was completed in 1998. Current Status: • The Navy is conducting monitoring for free product. • RAO is planned for September 1999.	Soil: Access was restricted and past exposures to the public were therefore highly unlikely. Present and future exposures are unlikely because access is still limited and future remedial activities will likely achieve cleanup goals. Groundwater: No production wells are located in this area; therefore, there were no past or current exposures to groundwater. Remedial activities should reduce contaminants in groundwater to levels that are protective of human health for any future uses.
#3-13316 Navy Exchange Building	Elevated concentrations of organic compounds in air and soil were detected during the installation of a vapor recovery line for a gasoline UST.	Soil: Collected samples were believed to have been contaminated by the gas line.	Corrective Activities: • In September 1995, 12 cy of contaminated soil were excavated. • Final Phase I Report was submitted in January 1997. • A Final RAM plan was submitted in April 1997. • Three USTs and 1,000 cy of contaminated soil were removed. • RAO submitted in July 1998. Current Status: • No further remedial action is planned.	Soil: Past exposures to the general public were unlikely due to access restrictions. USTs and contaminated soil were removed, thereby preventing present and future exposures.
#3-13673 Shea Drive	A Navy street sweeper leaked approximately 40 gallons of hydraulic oil along Shea drive. The Navy notified MADEP on April 18, 1996.	No environmental sampling was conducted.	Corrective Activities: • Spill was contained and cleaned up with sorbent material. • RAO submitted in June 1996. Current Status: • No further remedial action is planned.	Soil: Exposures to the general public were unlikely because the spill was contained and cleaned up quickly.
#3-14180 Building 116	During removal of gasoline USTs, elevated VOC vapors in soil were detected. The Navy notified the MADEP on August 30, 1996.	Soil: Soil screening detected VOC vapors. Confirmatory soil samples after excavation showed contamination was reduced to below MCP cleanup levels.	Corrective Activities: • USTs were removed. • RAO was submitted in July 1997. Current Status: • No further remedial action is planned.	Soil: Past exposures to the general public were unlikely due to site access restrictions and the inaccessibility of the soil. USTs were removed and soil contaminant levels were below MCP cleanup levels, thereby preventing present or future exposures.
#3-14646 Tanks 9A/9B	During removal of gasoline USTs, elevated VOC vapors in soil were detected. The Navy notified the MADEP on December 19, 1996.	Soil: Soil screening indicated VOC vapors. Confirmatory soil samples after excavation showed contamination was reduced to below MCP cleanup levels.	Corrective Activities: • USTs were removed. • RAO submitted in October 1997. Current Status: • No further remedial action is planned.	Soil: Past exposures to the general public were unlikely due to site access restrictions and the inaccessibility of the soil. USTs were removed and soil contaminant levels were below MCP cleanup levels, thereby preventing present or future exposures.
#3-14804 Quarters A	During removal of fuel oil USTs, elevated VOC vapors in soil were detected. The Navy notified the MADEP on February 7, 1997.	Soil: Soil screening detected VOC vapors. Confirmatory soil samples after excavation showed contamination was reduced to below MCP cleanup levels. Groundwater: Groundwater samples showed contamination above MCP cleanup levels.	Corrective Activities: • USTs and contaminated soil were removed. • Groundwater treatment performed. • IRA was completed and RAO submitted in February 1998. Current Status: • No further remedial action is planned.	Soil: Past exposures to the general public were unlikely due to access restrictions. USTs and contaminated soil were removed, thereby preventing present and future exposures. Groundwater: No production wells are located in this area; therefore, there were no past or current exposures to groundwater. Remedial activities should reduce contaminants in groundwater to levels that are protective of human health for any future uses.
#3-15289 Swimming Pool	During removal of a fuel oil UST, elevated VOC vapors in soil were detected. The Navy notified the MADEP on July 10, 1997.	Soil: Soil screening detected VOC vapors. Confirmatory soil samples after excavation showed contamination was reduced to below MCP cleanup levels. Groundwater: Three groundwater monitoring wells and Geoprobes were installed in October 1997. VOC vapors and oil were detected in groundwater.	Corrective Activities: • The UST and contaminated soil were removed and disposed of off site. The excavation was backfilled. • RAO submitted in July 1998. Current Status: • No further remedial action is planned.	Soil: Past exposures to the general public were unlikely due to access restrictions. The UST and contaminated soil were removed, thereby preventing present and future exposures. Groundwater: No production wells are located in this area; therefore, there were no past or current exposures to groundwater. Remedial activities should reduce contaminants in groundwater to levels that are protective of human health for any future uses.
#3-15342 Building 78	During removal of a fuel oil UST, elevated VOC vapors in soil were detected. The Navy notified the MADEP on July 28, 1997.	Soil: Soil screening detected VOC vapors. Confirmatory soil samples after excavation showed contamination was reduced to below MCP cleanup levels.	Corrective Activities: • UST and contaminated soil were removed and disposed of off site. The excavation was backfilled. • RAO submitted in December 1997. Current Status: • No further remedial action is planned.	Soil: Past exposures to the general public were unlikely due to access restriction. The UST and contaminated soil were removed, thereby preventing present and future exposures.
#3-15350 Building 14 (Supply)	During removal of a fuel oil UST, elevated VOC vapors in soil were detected. The Navy notified the MADEP on July 29, 1997.	Soil: Soil screening detected VOC vapors. Confirmatory soil samples after excavation showed contamination was reduced to below MCP cleanup levels.	Corrective Activities: • UST and contaminated soil were removed as allowable by structural constraints. • RAO submitted in May 1998. Current Status: • No further remedial action is planned.	Soil: Past exposures to the public were unlikely due to access restrictions. The UST and contaminated soil were removed, thereby preventing present and future exposures.
#3-15379 Building 24 (Medical)	During removal of a fuel oil UST, elevated VOC vapors in soil were detected. The Navy notified the MADEP on August 13, 1997.	Soil: Soil screening detected VOC vapors. Confirmatory soil samples after excavation showed contamination was reduced to below MCP cleanup levels.	Corrective Activities: • UST and contaminated soil were removed as allowable by structural constraints. • IRA completed. Current Status: • Navy will propose an AUL for soil beneath the boiler building foundation. • RAO projected for November 1999.	Soil: Past exposures to the public were unlikely due to access restrictions. Accessible contaminated soil was removed. Present exposure is unlikely because remaining contaminated soil is inaccessible. An AUL on the remaining inaccessible contaminated soil will prevent future exposure.
#3-15516 Building 116	During removal of gasoline USTs, elevated VOC vapors in soil were detected. The Navy notified the MADEP on September 11, 1997.	Soil: Soil screening detected VOC vapors.	Corrective Activities: • USTs and approximately 1,000 cy of contaminated soil were removed. • RAO submitted in September 1998. Current Status: • No further remedial action is planned.	Soil: Past exposures to the general public were unlikely due to access restrictions. USTs and contaminated soil were removed, thereby preventing present and future exposures.
#4-13224 Building 77 (Old Tower)	During removal of a UST, elevated VOC vapors in soil were detected. The Navy submitted written notification to the MADEP on September 25, 1997.	Soil: Soil screening detected VOC vapors. Confirmatory soil samples after excavation showed contamination was reduced to below MCP cleanup levels.	Corrective Activities: • UST and contaminated soil were removed and disposed of off site. The excavation was backfilled. • RAO submitted December 1997. Current Status: • No further remedial action is planned.	Soil: Past exposures to the general public were unlikely due to access restrictions. The UST and contaminated soil were removed, thereby preventing present and future exposures.
#3-15816 Quarters F	During removal of a 500- gallon No. 2 fuel oil UST, elevated VOC vapors in soil were detected. The Navy notified the MADEP in December 1997.	Soil: Soil screening detected VOC vapors. Groundwater: Free product encountered during the excavation operations.	Corrective Activities: • Free product recovery was set up during excavation operations. Current Status: • Free product recovery system operating. • UST and contaminated soil will be removed and disposed of off site under IRA in process. • RAO projected for December 2000.	Soil: Past exposures to the general public were unlikely due to access restrictions (the tank was underground). Present and future exposures are unlikely because access is still limited and future remedial activities will likely achieve cleanup goals.
#3-15822 Quarters B	During removal of a 500- gallon No. 2 fuel oil UST, elevated VOC vapors in soil were detected. The Navy notified the MADEP in December 1997.	Soil: Soil screening detected VOC vapors.	Corrective Activities: • UST and contaminated soil were removed in December 1997 and disposed of off site. • RAO submitted February 1998. Current Status: • No further remedial action is planned.	Soil: Past exposures to the general public were unlikely due to access restrictions (the tank was underground). The UST and contaminated soil were removed, thereby preventing present and future exposures.
#3-15823 Quarters G	During removal of a 500- gallon No. 2 fuel oil UST, elevated VOC vapors in soil were detected. The Navy notified the MADEP in December 1997.	Soil: Soil screening detected VOC vapors.	Corrective Activities: • UST and contaminated soil were removed in December 1997 and disposed of off site. • RAO submitted February 1998. Current Status: • No further remedial action is planned.	Soil: Past exposures to the general public were unlikely due to access restrictions (the tank was underground). The UST and contaminated soil were removed, thereby preventing present and future exposures.
#3-15829 Barracks 115	During removal of a heating fuel UST, elevated VOC vapors in soil were detected. The Navy notified the MADEP in December 1997.	Soil: Soil screening detected VOC vapors.	Corrective Activities: • UST and contaminated soil were removed in December 1997 and disposed of off site. • RAO submitted February 1998. Current Status: • No further remedial action is planned.	Soil: Past exposures to the general public were unlikely due to access restrictions (the tank was underground). The UST and contaminated soil were removed, thereby preventing present and future exposures.
#3-16598 Jet Fuel Pipeline	During excavation of a 550-gallon holding tank and 4,200 feet of piping, soil contaminants were identified. The Navy notified MADEP in March 1998.	Soil: Twenty-four post excavation samples were collected and screened for TPH. Soil contamination was limited to the subsurface. Groundwater: Four samples were analyzed for TPH.	Corrective Activities: • UST and 1,000 cy of contaminated soil were excavated and disposed of off site. • IRA Plan was submitted in May 1998. • Phase I Site Investigation Report was submitted in March 1999. Current Status: • Additional investigations are planned.	Soil: Past exposures were unlikely because contamination was limited to the subsurface. The Navy removed contaminated soil to prevent present and future exposures. Groundwater: No production wells are located in this area; therefore, there were no past or present exposures to groundwater. Remedial activities should reduce contaminants in groundwater to levels that are protective of human health for any future uses.
#3-17527 Building 14	During excavation of an oil/water separator and floor drains, soil contaminated with fuel components was identified. The Navy notified MADEP in November 1998.	Soil: Subsurface soil samples contained TPH and methyl tertiary-butyl ether. Groundwater: No groundwater sampling has been completed.	Corrective Activities: • Limited Removal Action was completed to remove 91 cy of contaminated soil. • An additional 260 cy of contaminated soil were removed under a RAM Plan. Current Status: • Groundwater sampling is planned. • Additional soil investigations and removals, if necessary, are planned.	Soil: Past exposures were unlikely because contamination was limited to the subsurface. The Navy removed contaminated soil and is planning additional actions, if necessary, to prevent present and future exposures. Groundwater: No production wells are located in this area; therefore, there were no past or present exposures to groundwater. Remedial activities should reduce contaminants in groundwater to levels that are protective of human health for any future uses.
#3-18110 Building 82	During excavation and cleaning of floor drains, contaminated soil was identified. The Navy notified MADEP in March 1999.	Soil: Ten soil borings were collected and TPH was detected. Groundwater: No groundwater sampling has been completed.	Corrective Activities: • In September 1998, an oil/water separator was removed; floor drains and manholes were cleaned; and sewer connections were sealed. Current Status: • Investigation and remediation is ongoing.	Soil: Past exposures were unlikely because contamination was limited to the subsurface. The Navy will conduct remedial actions to prevent present and future exposures. Groundwater: No production wells are located in this area; therefore, there were no past or present exposures to groundwater. Remedial activities should reduce contaminants in groundwater to levels that are protective of human health for any future uses.
MCP SITES LOCATED AT SQUANTUM GARDENS
#3-11322 Squantum Boiler Room UST	The now defunct Boiler Room/Heating Plant Building contained an abandoned 8,700-gallon UST, possibly dating back to the 1950s.	Soils: No soil sampling occurred. Groundwater: No groundwater sampling occurred.	Corrective Activities: • MADEP was notified of the UST on September 29, 1994. • The UST was removed in June 1995. Current Status: • No further remedial action is planned.	Soil: No known soil contamination exists because the release occurred within a boiler room. Past exposure to the general public is unknown. Current and future exposures do not pose a public health hazard because the UST has been removed and the building has been demolished. Groundwater: No known groundwater contamination exists. There are no known private drinking water wells in the area. Past, current, and future exposures are unlikely.
#3-12562 Squantum 2,700- Gallon UST	An abandoned 2,700- gallon UST was discovered in the area south of the Administration/ Maintenance Building on June 9, 1995. It was removed to prevent or limit future gasoline releases.	Soil: Volatile organic vapors were detected at greater than 200 ppm in the soil in the immediate vicinity of the UST. Groundwater: No groundwater sampling has occurred.	Corrective Activities: • The 2,700-gallon UST was removed in June 1995 and the surrounding area was excavated. • Subsurface soil borings and wells have been installed to characterize the site. Current Status: • No further remedial action is planned.	Soil: Access to the site is restricted and past exposures to the general public were therefore highly unlikely. Groundwater: Although no known private drinking water wells are in the area, no groundwater sampling has occurred to evaluate this exposure pathway.
#3-14078 Squantum Gardens	The Navy notified the MADEP when samples of excavated soil from Squantum Gardens indicated contamination above reportable concentrations.	Soil: SVOCs and metals were detected in soil samples.	Corrective Activities: • Some contaminated soil was excavated. • An AUL was recorded. • RAO submitted in June 1998. Current Status: • No further remedial action planned.	Soil: Past exposures to the general public were unlikely due to access restrictions (soil contamination was below ground surface). Present and future exposures are unlikely because access is still limited and future remedial activities will likely achieve cleanup goals.

APPENDIX B: Evaluation of Potential Public Health Hazards Associated With the USCG Buoy Depot

Parcel	Site Description/Waste Disposal History	Environmental Monitoring Results	Corrective Activities and Current Status	ATSDR's Evaluation of Public Health Hazards
1: Depot building	Paints, thinners, and oils have been used in and adjacent to this building. There is no evidence of a release.	No monitoring has been conducted because there is no evidence of a release.	Corrective Activities: • None. Current Status: • No further remedial action is planned.	The site poses no public health hazard because there is no evidence of a release.
2: Septic tank	This is an active septic system currently used at the depot. Unknown hazardous wastes may have been discharged to this septic system.	Soil: Two subsurface soil samples were analyzed and did not contain contaminants above comparison values. Groundwater: One well was sampled and contained PAHs and lead slightly above comparison values	Corrective Activities: • None. Current Status: • Additional sampling and site investigations are planned.	Soil: The site poses no apparent public health hazard because any potential contamination appears to be limited to within the fenceline and below the ground's surface. Groundwater: The site poses no apparent public health hazards because groundwater is not flowing toward private wells and contamination is minimal.
3: Suspected former septic tank	Existence of this tank is uncertain. Unknown hazardous wastes may have been disposed of in this tank.	Soil: Four subsurface soil samples were analyzed and did not contain contaminants above comparison values. Groundwater: Two wells were sampled and contained cadmium, lead, and methylene chloride slightly above comparison values. The methylene chloride is likely the result of laboratory contamination. Subsurface Survey: No evidence of the former septic tank or leaching field was identified.	Corrective Activities: • None. Current Status: • Additional sampling and site investigations are planned.	Soil: The site poses no apparent public health hazard because any potential contamination appears to be limited to within the fenceline and below the ground's surface. Groundwater: The site poses no apparent public health hazards because groundwater is not flowing toward private wells and contamination is minimal.
4: Sand blast residues piles	During the Phase I EBS, residue from sandblasting buoys was observed beneath a dust collector located along the southwest corner and to the west of the depot building.	Soil: Surface soil sampling detected lead below comparison values. Groundwater: No groundwater monitoring has been conducted in this area.	Corrective Activities: • None. Current Status: • Additional sampling and site investigations are planned.	The site poses no apparent public health hazard because no contaminants have been detected above comparison values and any potential contamination appears to be limited to within the fenceline. ATSDR will evaluate additional sampling data when it becomes available.
5: Dust collection system	During the Phase I EBS, staining was observed around the dust collection system. An operational malfunction caused residues around the dust collection system.	Soil: Surface soil sampling detected lead above comparison values in one sample. Groundwater: No groundwater monitoring has been conducted in this area.	Corrective Activities: • None. Current Status: • Additional sampling and site investigations are planned.	The site poses no apparent public health hazard because contamination appears to be limited to within the fenceline. ATSDR will evaluate additional sampling data when it becomes available.
6: MCP Spill #3-15182 Soil remediation area	Diesel fuel was released over time from 55-gallon drums of diesel fuel used to fuel equipment. MADEP was notified on July 28, 1997. Fuel drums are no longer used.	Soil: Soil screening detected VOC vapors. Confirmatory soil samples after excavation showed contamination was reduced to below MCP cleanup levels.	Corrective Activities: • 115 cy of soil were removed. • RAO submitted. Current Status: • No further remedial action is planned.	Soil: Past exposures to the general public were unlikely due to access restrictions. Contaminated soil was removed. No current or future exposures exist.
7: Septic leach field	Unknown potential discharges including discharges from floor drains. (Floor drains have been plugged for 10 years.)	Soil: Four subsurface soil samples were analyzed and did not contain contaminants above comparison values. Groundwater: One well was sampled and contained lead and methylene chloride above comparison values. The methylene chloride is likely the result of laboratory contamination.	Corrective Activities: • None. Current Status: • Additional sampling and investigations are planned.	Soil: The site poses no apparent public health hazard because any potential contamination appears to be limited to within the fenceline and below the surface. Groundwater: The site poses no apparent public health hazards because groundwater is not flowing toward private wells and contamination is minimal.
8: Equipment and scrap metal storage area	This area is used for storage of scrap metal and buoys by the USCG. Past aerial photographs indicate that the Navy used this area to store scrap metal before construction of the USCG Buoy Depot.	Soil: Surface soil sampling detected lead above comparison values in one sample. Groundwater: One well was sampled and contained lead and methylene chloride above comparison values. The methylene chloride is likely the result of laboratory contamination.	Corrective Activities: • None. Current Status: • Drums will be removed. • Additional sampling and investigations are planned.	Soil: The site poses no apparent public health hazard because any potential contamination appears to be limited to within the fenceline. Groundwater: The site poses no apparent public health hazards because groundwater is not flowing toward private wells and contamination is minimal.

APPENDIX C: Comparison Values

The conclusion that a contaminant exceeds the comparison value does not mean that it will cause adverse health effects. Comparison values represent media-specific contaminant concentrations that are used to select contaminants for further evaluation to determine the possibility of adverse public health effects.

Cancer Risk Evaluation Guides (CREGs)
Estimated contaminant concentrations that would be expected to cause no more than one excess cancer in a million (10^-6) persons exposed over a 70-year life span. ATSDR's CREGs are calculated from EPA's cancer potency factors.

Environmental Media Evaluation Guides (EMEGs)
EMEGs are based on ATSDR minimal risk levels (MRLs) and factors in body weight and ingestion rates. An EMEG is an estimate of daily human exposure to a chemical (in mg/kg/day) that is likely to be without noncarcinogenic health effects over a specified duration of exposure.

Reference Media Evaluation Guides (RMEGs)
ATSDR derives RMEGs from EPA's oral reference doses (RfDs). The RMEG represents the concentration in water or soil at which daily human exposure is unlikely to result in adverse noncarcinogenic effects.

Maximum Contaminant Level (MCL)
The MCL is the drinking water standard established by EPA. It is the maximum permissible level of a contaminant in water that is delivered to the free-flowing outlet. MCLs are considered protective of public health over a lifetime (70 years) for people consuming 2 liters of water per day.

Risk-Based Concentration (RBC)
The RBCs were developed by EPA Region III. RBCs for tap water, air, and soil were derived using EPA RfDs and cancer potency factors combined with standard exposure scenarios, such as ingestion of 2 liters of water per day, over a 70-year life span. RBCs are contaminant concentrations that are not expected to cause adverse health effects over long-term exposures.

Soil Screening Level (SSL)
Generic SSLs were derived by EPA for nation-wide application to sites used for residential areas. SSLs are an estimate of contaminant concentrations that would be expected to be without noncancer health effects over a specified duration of exposure or to cause no more than one excess cancer in a million (10^-6) persons exposed over a 70-year life span.

APPENDIX D: Glossary

Activity Use Limitation (AUL): Under the Massachusetts Contingency Plan, in cases when a chemical release cannot be cleaned to MCP standards (e.g., contaminated soil found under a building that cannot be removed), the responsible party may place an AUL on the contaminated area. This AUL is a deed restriction that prohibits unsafe usage of property by current or future owners.

Background Level: A typical or average level of a chemical in the environment. Background often refers to naturally occurring or uncontaminated levels
Carcinogen: Any substance that may produce cancer.
CERCLA: The Comprehensive Environmental Response, Compensation, and Liability Act of 1980, also known as Superfund. This is the legislation that created ATSDR.
Comparison values: Estimated contaminant concentrations in specific media that are not likely to cause adverse health effects, given a standard daily ingestion rate and standard body weight. The comparison values are calculated from the scientific literature available on exposure and health effects.
Concentration: The amount of one substance dissolved or contained in a given amount of another. For example, sea water contains a higher concentration of salt than fresh water.
Contaminant: Any substance or material that enters a system (the environment, human body, food, etc.) where it is not normally found.
Dermal: Referring to the skin. Dermal absorption means absorption through the skin.
Dose: The amount of substance to which a person is exposed. Dose often takes body weight into account.
Environmental contamination: The presence of hazardous substances in the environment. From the public health perspective, environmental contamination is addressed when it potentially affects the health and quality of life of people living and working near the contamination.
Exposure: Contact with a chemical by swallowing, by breathing, or by direct contact (such as through the skin or eyes). Exposure may be short term (acute) or long term (chronic).
Hazard: A source of risk that does not necessarily imply potential for occurrence. A hazard produces risk only if an exposure pathway exists, and if exposures create the possibility of adverse consequences.
Ingestion: Swallowing (such as eating or drinking). Chemicals can get in or on food, drink, utensils, cigarettes, or hands where they can be ingested. After ingestion, chemicals can be absorbed into the blood and distributed throughout the body.
Inhalation: Breathing. Exposure may occur from inhaling contaminants because they can be deposited in the lungs, taken into the blood, or both.
Immediate Response Action (IRA): Under the MCP, an IRA can be any of a number of assessments or actions performed quickly to address a sudden chemical release.
Massachusetts Contingency Plan (MCP): The MCP is the Massachusetts Department of Environmental Protection regulation for reporting, assessing, and cleaning up releases of oil and hazardous material.
Media: Soil, water, air, plants, animals, or any other parts of the environment that can contain contaminants.
National Priorities List: The Environmental Protection Agency's (EPA) listing of sites that have undergone preliminary assessment and site inspection to determine which locations pose immediate hazard to persons living or working near the release. These sites are most in need of cleanup.
No Apparent Public Health Hazard: Sites where human exposure to contaminated media is occurring or has occurred in the past, but the exposure is below a level of health hazard.
Plume: An area of chemicals in a particular medium, such as air or groundwater, moving away from its source in a long band or column. A plume can be a column of smoke from a chimney or chemicals moving with groundwater.
Potentially Exposed: The condition where valid information, usually analytical environmental data, indicates the presence of contaminant(s) of a public health concern in one or more environmental media contacting humans (i.e., air, drinking water, soil, food chain, surface water), and there is evidence that some of those persons have an identified route(s) of exposure (i.e., drinking contaminated water, breathing contaminated air, having contact with contaminated soil, or eating contaminated food).
Public Health Assessment: The evaluation of data and information on the release of hazardous substances into the environment to assess any current or future effects on public health, develop health advisories or other recommendations, and identify studies or actions needed to evaluate and mitigate or prevent human health effects; also, the document resulting from that evaluation.
Public health hazard: Sites that pose a public health hazard as the result of long-term exposures to hazardous substances.
Release Abatement Measure (RAM): Under the MCP, a RAM is an action that may be taken by the responsible party to limit or localize a chemical release until a more comprehensive remedial action can be taken.
Response Action Outcome (RAO): Under the MCP, when cleanup of a chemical release is complete the responsible party submits an RAO to the MADEP. The RAO classifies the disposal site as posing no significant risk.
Risk: In risk assessment, the probability that something will cause injury, combined with the potential severity of that injury.
Route of exposure: The way in which a person may contact a chemical substance. For example, drinking (ingestion) and bathing (skin contact) are two different routes of exposure to contaminants that may be found in water.
Superfund: Another name for the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), which created ATSDR.
Superfund Amendments and Reauthorization Act (SARA): The 1986 legislation that broadened ATSDR's responsibilities in the areas of public health assessments, establishment and maintenance of toxicologic databases, information dissemination, and medical education.
Total petroleum hydrocarbons: The total cumulative concentration of hydrocarbons associated with a petroleum product containing 10 or more carbon atoms.
Volatile organic compounds (VOCs): Substances containing carbon and different proportions of other elements such as hydrogen, oxygen, fluorine, chlorine, bromine, sulfur, or nitrogen; these substances easily become vapors or gases. A significant number of the VOCs are commonly used as solvents (paint thinners, lacquer thinner, degreasers, and dry cleaning fluids).

APPENDIX E: Responses to Public Comments

The Agency for Toxic Substances and Disease Registry (ATSDR) received the following comments/questions during the public comment period (March 4 to April 19, 1998) for the SWNAS Public Health Assessment (PHA) (March 4, 1998). For comments that questioned the validity of statements made in the PHA, ATSDR verified or corrected the statements. The list of comments does not include editorial comments concerning such things as word spelling or sentence syntax.

General

Comment: Sampling data used to conclude that there are no public health hazards should be included in the report. Specifically, results of on-site, perimeter, and off-site well sampling; surface water and sediment sampling with reference to the sampling source (e.g., stream or standing water); and surface and subsurface soil sampling from the Remedial Investigation (RI) for the seven Installation Restoration Program (IRP) sites should be provided. Data from investigations of the United States Coast Guard (USCG) sites should be identified and included. Did contaminant concentrations detected in these data sets exceed ATSDR health-based comparison values? Without the raw data, the assessment is not a comprehensive technical document and is difficult to review as such.
Response: The Navy sampled South Weymouth Naval Air Station (SWNAS) under a RI completed in January 1997. ATSDR relied on sampling results from this investigation to conduct the public health evaluation. To keep the document concise and easily accessible to the public, ATSDR does not include the raw data as an appendix to the PHA. The RI, including the raw data, are available at public repositories (Abington, Hingham, Rockland, and Weymouth libraries and the Navy Caretaker Office at SWNAS). Additional site sampling and analysis is ongoing under a Phase II Environmental Baseline Survey (EBS) and Phase II RI. ATSDR will evaluate new data as they relate to public health issues.
No samples were collected from the USCG Buoy Depot under the Phase I RI, but soil and groundwater sampling was conducted under the Phase II EBS completed for the Buoy Depot in September 1998. These data were reviewed and incorporated into the PHA. ATSDR did not identify any apparent public health hazards associated with contaminants detected at the depot. Additional sampling is planned, and ATSDR will evaluate these data as they relate to public health issues.
For all site-related data evaluated for this PHA, ATSDR compared concentrations of contaminants detected in site media against health-based comparison values. Tables 2 through 11 of the PHA summarize by IRP site those contaminants found above comparison values, specifically groundwater data from IRP sites, perimeter well data, and surface water and sediment data from French's Stream and Old Swamp River. Comparison values are derived assuming extremely conservative assumptions (protective of public health) about the amount, the frequency, and the duration of potential exposures to a contaminant. The presence of contaminants above their comparison values indicates that further evaluation should be conducted, rather than indicating that adverse health effect will occur. When a contaminant exceeds it comparison value, ATSDR examines potential exposure variables, such as how often and how long a person may contact contaminated media, and contaminant toxicity under site-specific conditions to assess the potential for adverse health effects.
Comment: Ongoing investigations are being conducted at SWNAS. This should be clearly stated in the PHA and new data should be evaluated and considered once available.
Response: The Remedial and Regulatory History section of the PHA lists the investigations and documents that will be completed in the future. When possible, the estimated completion date is included. ATSDR will review additional data as they relate to public health issues. ATSDR will take appropriate public health actions as needed.
Comment: Is it appropriate to draw a conclusion of no apparent public health hazards based on assumptions of risk management actions, assumed remediation, or limited data? Assumptions used to reach this conclusion should be clarified.
Response: ATSDR reaches a conclusion about the potential for site contamination to pose a public health hazard based on an evaluation of potential exposures, as detailed in Figure 5. The first step in this evaluation process is to determine if exposures may occur under past, current, and future site uses. It is reasonable to conclude that no future exposures will occur if risk management actions and planned remediation activities will prevent or limit exposures. ATSDR added a recommendation to the PHA to re-evaluate the potential for public health hazards if changes in land use, remedial activities, or risk management actions may lead to future exposures.
With regard to past and current exposures, sufficient data are available to draw a conclusion of no apparent public health hazards. The Navy collected and analyzed groundwater, surface water, sediment, and surface soil samples during the Phase I RI. These samples contained low levels of contaminants. Additional data are being collected during the Phase II EBS and the Phase II RI to further characterize site conditions. ATSDR evaluated the potential for adverse health effects based on detected contaminant concentrations and likely exposures and found that contact with low levels of contaminants in site media is unlikely to result in adverse health effects. The evaluation process and factors considered to draw this conclusion are more clearly discussed in the groundwater, surface water and sediment, and soil exposure sections of the PHA.
Comment: Toxicological data, specifically for contaminants of concern at the site, are not presented in the PHA and would be useful in providing a better understanding of hazards. Of specific concern was the use of the arsenic Maximum Contaminant Level (MCL) because the EPA water standards for arsenic have not changed since 1942.
Response: The MCL for arsenic is provided for information purposes. The comparison value used for arsenic was the ATSDR-derived cancer risk evaluation guide (CREG). The CREG is based on current toxicological data and was most recently re-evaluated by ATSDR in 1993.
In addition, the potential health effects that are detailed in the toxicological data are relevant only if people are exposed to a contaminant often enough and for long enough for health effects to occur. Because no potential exposures were identified that might result in adverse health effects at SWNAS, providing toxicological data might cause unnecessary community alarm. However, toxicological profiles are available on the ATSDR Web site (www.atsdr.cdc.gov) if more information is wanted.
Comment: Several rare cancers have been found to be prevalent in Weymouth. Cancer of the pancreas was found to be 200% greater in Weymouth than the State average. The cause remains a mystery.
Response: In 1996, the Massachusetts Department of Public Health (MADPH) completed an evaluation of cancer incidence data for 10 cancer types from 1982 to 1996 for the four communities surrounding SWNAS. Based on the cancer incidence data, MADPH found no clear pattern of elevations of any one primary site of cancer across all four communities. MADPH, however, is continuing to study this concern and the results of an ongoing evaluation should be available for review. In addition, ATSDR's evaluation of SWNAS has not shown that people are exposed to contaminants at levels of health concern.
Comment: What potential future land uses were considered? What are the potential future exposures to contamination in soil, groundwater, surface water, and sediment? Redevelopment of the site is progressing, and the current reuse plan has been approved by the three towns occupied by SWNAS.
Response: The South Shore Tri-Town Development Corporation (SSTTDC) was formed to evaluate potential reuse options and to execute redevelopment. The current redevelopment plan calls for a mixed use of the site, including commercial, residential, and recreational/conservation areas. As proposed, none of the residential areas are located within the boundaries of IRP sites.
The PHA considered that the site would be redeveloped for a mixture of commercial and residential uses, which encompasses possible future land use under redevelopment plans being considered by the SSTTDC. Potential exposures to contamination in soil, groundwater, surface water, and sediment are discussed in the "Evaluation of Environmental Contamination and Potential Exposure Pathways" section of the PHA.
Comment: Since release of the PHA, have more Massachusetts Contingency Plan (MCP) sites been established? If so, will these be evaluated? Which MCP sites were included in the assessment and why were these sites omitted from the Potential Exposure Pathway Table?
Response: In June 1999, ATSDR conducted a search of the MADEP database listing MCP sites and identified four additional MCP sites that have been reported since the release of the public comment release of the PHA. These sites have been included in Appendix A.
In addition to the seven IRP sites at SWNAS, investigations also identified a total of 27 MCP sites at SWNAS and 3 MCP sites at Squantum Gardens. ATSDR evaluated each of these sites to assess the potential for public health hazards. Generally, the MCP sites consist of small leaks or spills of petroleum products which were addressed quickly with remedial actions to remove contaminants from affected media. Most of these spills also occurred in restricted portions of SWNAS. Past exposures would have been limited to site workers. Past exposures also would have been infrequent and of short duration because they remediated the sites quickly. Based on evaluations of potential exposures and remedial actions, ATSDR concluded that the MCP sites pose no apparent health hazard. Appendix A provides details regarding the evaluation of potential health hazards associated with each MCP site. MCP sites were excluded from the Potential Exposure Pathway Table as potential sources because these sites are either undergoing remediation or remediation is completed and they are no longer ongoing sources of contamination. Therefore, these sites do not represent complete exposure pathways.
Comment: Who is responsible for performing recommended actions?
Response: ATSDR is a non-regulatory agency. Therefore, recommended actions were discussed with the Navy and regulatory agencies to determine appropriate actions and to assign responsibility. At SWNAS, recommended actions include reviewing new data if investigations indicate that potential adverse health may occur or if land use, remedial activities, or risk management actions change. ATSDR is responsible for reviewing data and re-assessing potential public health hazards at SWNAS. This PHA also recommends removal of physical hazards, which will be addressed by the Navy.

Groundwater

Comment: The assumptions used to conclude that groundwater does not pose an apparent health hazard need to be clarified. Driving assumptions used to reach this conclusion are that the groundwater will not be used as a drinking water source and contaminants have not migrated off site. The conclusion of no apparent public health hazard could be misinterpreted if this assumption is not clearly presented.
Response: The evaluation process and factors considered to draw conclusions were more thoroughly discussed in the groundwater exposure section of this PHA. Although groundwater underlying SWNAS is not used as a drinking water supply, future reuse may include developing this resource. Investigations of groundwater quality and potential yield will be required should this occur. These investigations would be conducted with regulatory oversight to ensure the continued protection of the public and the safety of the municipal water supply. ATSDR added a recommendation to the PHA that, if groundwater is developed as a drinking water supply in the future, ATSDR will assess future exposures.
On-site data indicate that groundwater around portions of SWNAS is flowing from surrounding neighborhoods toward discharge points in either French's Stream or Old Swamp River. To date, groundwater sampling has not identified contaminant plumes at any of the IRP sites. A small plume of tetrachloroethylene (PCE) was detected at a MCP site located near Building 81, however, this plume is entirely contained within SWNAS boundaries. In 1998, the Navy excavated and disposed of off site approximately 1,250 cubic yards of contaminated soil identified as the source of the PCE in groundwater. The Navy is continuing to assess potential groundwater remediation alternatives to treat groundwater and prevent plume migration. Based on this information, ATSDR concluded that contamination is not migrating off site. This information is more thoroughly discussed in this PHA.
Comment: The PHA states that groundwater contamination has not migrated off site, however, only perimeter wells have been sampled. These perimeter wells only evaluate shallow groundwater and have not been monitored to track seasonal variations. No off-site wells have been monitored. In addition, groundwater flow direction, flow rate, and their affect on contaminant movement should be provided. Does SWNAS serve as a recharge area for the underlying aquifers? Is it possible that contamination originating at the West Gate Landfill is affecting the Hingham Street Reservoir? Off-site wells should be sampled.
Response: During the Phase I RI, the Navy installed and sampled groundwater wells located around the perimeter of SWNAS and within each of the seven IRP sites. The intent of groundwater sampling was to assess groundwater flow direction and to identify potential groundwater contamination. Groundwater was found to flow toward discharge points within French's Stream and Old Swamp River. Therefore, in most locations, groundwater is flowing on site from surrounding neighborhoods and is unlikely to transport contaminants off site.
Surface water bodies, such as wetlands and ponds, and precipitation are the sources of recharge to aquifers that underlie SWNAS and surrounding communities. Based on groundwater flow directions, it is unlikely that groundwater at SWNAS is affecting the Hingham Street Reservoir located east of SWNAS.
Additional groundwater sampling under the Phase II EBS and the Phase II RI includes installing and sampling monitoring wells in the deep overburden and bedrock aquifers. The intent of additional groundwater sampling is to further characterize groundwater flow and potential contaminant migration. If off-site contaminant migration is identified during these investigations, potential exposures to contaminants in private wells should be further assessed.
Comment: Only shallow groundwater wells (3-15 feet below ground surface [bgs]) have been installed at the IRP sites and background locations. In ATSDR's experience is this standard procedure for a Phase I investigation at a site like the SWNAS?
Response: The majority of the monitoring wells installed during the Phase I RI sampled groundwater from 3 to 20 feet bgs, however, four wells sampled groundwater from 20 to 38 feet bgs. The intent of the Phase I RI was to characterize the nature and extent of contamination at the seven IRP sites and to assess risk to human health under the EPA risk assessment process. The information from the Phase I RI is then used to identify the next appropriate steps for addressing contamination at each site. Often, as is the case with SWNAS, the next step is to conduct additional sampling. The Phase II RI includes sampling deeper groundwater wells (greater than 15 feet bgs) and bedrock wells. The results of the Phase II RI will be used to further assess remedial action needs.
Comment: The term "plume" should be defined and how plumes are identified should be described. The PHA states that no plumes have been identified on site, however, a small area of PCE contamination and some areas of floating product (gasoline) exist.
Response: A definition of "plume" and a brief description how plumes are identified was added to the PHA. The PHA has also been revised to address the area (approximately 50 feet wide and 200 feet long) of PCE contamination and floating product, also referred to as light non-aqueous phase liquid (LNAPL).
Comment: One of the recommendations was to conduct a well inventory of Rockland because this town does not have a database of private wells. This inventory could be expanded to Weymouth, Hingham, and Abington to generate a more complete listing than the databases currently available. New wells are being installed frequently, especially in Weymouth. Therefore, it is especially important to have an accurate record of private wells. Should these more thorough well inventories be conducted before or after more data on groundwater contamination is gathered?
Response: The Boards of Health from Abington, Hingham, Rockland, and Weymouth have identified private wells located proximate to SWNAS. In Abington, Hingham, and Weymouth, the Boards of Health maintain records of private wells that are updated regularly and they provided these records to ATSDR. The Hingham Board of Health conducted a survey in November 1998 to update information for property located proximate to SWNAS. In February and March 1999, the Rockland Board of Health conducted a survey of the neighborhoods proximate to SWNAS to identify homes with private wells and their uses. As a result of the records review and survey, 53 active private wells were identified in the four surrounding communities at properties proximate to the site. Of these 53 wells, 8 are used as a drinking water supply, 35 are used for non-potable purposes (irrigation and monitoring), and 10 wells have unidentified uses. This information was incorporated into the PHA. ATSDR recognizes that some wells may be omitted from the well records. Therefore, if off-site contaminant migration is found, ATSDR recommends that local, state, and federal regulators and organizations coordinate to confirm well locations and uses.
Comment: The Swamp River Aquifer was not addressed.
Response: The Swamp River Aquifer underlies the Old Swamp River drainage basin. Abington, Rockland, and Weymouth water supplies do not access groundwater within the Swamp River Aquifer for their municipal water supplies. Hingham pumps drinking water from groundwater wells that may access this aquifer, however, the supply wells are located over 1 mile away from the site. Information regarding the Swamp River Aquifer was added to the groundwater exposure evaluation section of the PHA.

Surface Water and Sediment

Comment: The PHA indicates that surface water and sediment samples were collected at each of the seven IRP sites. Is there really surface water and sediment at each of these sites?
Response: Under the Phase I RI, the Navy collected surface water and sediment from Old Swamp River and/or associated wetlands at the Rubble Disposal Area and background locations. The Navy also collected surface water and sediment from French's Stream, associated wetlands, and/or drainage ditches discharging to the stream at the West Gate Landfill, Fire-Fighting Training Area, Tile Leach Field, Sewage Treatment Plant, Abandoned Bladder Tank Storage Area, and background locations. The PHA was revised to reflect this information. Contaminants detected above comparison values in French's Stream and Old Swamp River are presented in Tables 10 and 11, respectively.
Comment: Several contaminants (e.g., antimony) were detected above comparison values in surface water and/or sediment, however, the PHA concluded that there were no apparent public health hazards. The assumptions used to make this conclusion should be clearly stated. What is the potential source of the high concentration of antimony in the upstream sample from Old Swamp River? How can the PHA conclude that antimony does not present a health hazard when the water department does not test for antimony under their monitoring program? Contaminants in Old Swamp River may affect people using the Weymouth municipal water supply.
Response: The evaluation process and factors considered to reach the conclusion of no apparent public health hazard are more thoroughly discussed in the surface water and sediment exposure evaluation section of the PHA. Two metals (antimony and manganese) were detected in Old Swamp River above comparison values. The source of elevated antimony in the one upstream sample is unknown. No antimony was detected above its comparison value in downstream samples. Manganese was also detected in upstream and downstream samples above its comparison value. Comparison values are derived assuming extremely conservative assumptions (protective public health) about the amount, the frequency, and the duration of potential exposures to a contaminant. When a contaminant exceeds its comparison value, ATSDR examines potential exposure variables, such as how often and how long a person may contact contaminated media, and contaminant toxicity under site-specific conditions to assess the potential for adverse health effects. Within Old Swamp River, antimony concentrations will likely remain stable or decrease between SWNAS and the Weymouth water supply. Current sampling found antimony above its comparison value in the upstream sample from SWNAS, but antimony decreased to concentrations below its comparison value at the downstream sample. Water from Old Swamp River is combined with water from other sources and treated prior to distribution. These processes likely decrease the antimony and manganese concentrations below that detected in on-site samples. Comparison values also consider that a person is using water with the detected antimony and manganese concentrations as their primary drinking water supply. No water supply intakes are located immediately adjacent to the sample location and Old Swamp River only supplies a small portion of the total water supply to the Weymouth community. Currently no more than 10% and historically only 20% of the total water supply was provided by Old Swamp River. Therefore, even though Weymouth does not test their water supply for antimony or manganese, ATSDR concluded that these metals pose no apparent public health hazards.
Comment: Polychlorinated biphenyls (PCBs) were manufactured until the 1970s and it is likely that PCBs were used at SWNAS prior to this. Annual flooding could transport PCBs in soil on the banks of Old Swamp River to the river. Is it possible that, over time, PCBs have migrated downstream in the sediment? PCB-contaminated soil should be removed.
Response: The Phase II EBS and Phase II RI sampling programs include analyzing soil and sediment for multiple contaminants, including PCBs. To account for potential migration through flooding, sampling includes locations at the downstream site boundary. If contaminants are detected at levels of concern, the Navy will conduct appropriate remedial actions to prevent contaminant migration and protect public health. The U.S. Environmental Protection Agency (EPA) and Massachusetts Department of Environmental Protection (MADEP) are the regulatory authorities that approve and enforce remedial actions to ensure public health is protected.
Comment: Does the SWNAS drainage system collect groundwater from heavily contaminated areas and discharge this contaminated water to Old Swamp River and French's Creek. If so, filters that remove contamination should be installed on the drainpipes prior to discharge.
Response: Drainage at SWNAS eventually discharges to either Old Swamp River or French's Stream. The Phase I RI investigations included sampling drainage ditches, Old Swamp River, and French's Stream at the IRP sites, as well as up and downstream of SWNAS, to identify contamination that may have migrated to surface water through the drainage system. Only three contaminants (arsenic, iron, and manganese) have been detected above comparison values, but below levels of health concern, in downstream surface water and sediment samples from French's Stream and Old Swamp River, as discussed in the "Evaluation of Surface Water and Sediment Exposure Pathway" section of this PHA. The Phase II EBS and Phase II RI investigations include additional surface water and sediment sampling within catch basins, drainage outlets, Old Swamp River, and French's Stream. Based on investigation results, the Navy will conduct appropriate remedial actions to prevent future migration of contamination and protect public health. While industrial operations were active at the site, discharge was regulated by a National Pollution Discharge Elimination System (NPDES) permit that calls for regular sampling for oil and grease, settleable solids, suspended soils, and pH at the drainage outlets. Currently, sampling under this permit has been suspended because industrial activities have ceased.
Comment: Additional information was provided about the path surface water follows when leaving SWNAS via Old Swamp River. Old Swamp River flows from SWNAS to Whitman's Pond. Water is then pumped from Whitman's Pond to Great Pond, which is South Weymouth's primary drinking water supply. The PHA estimated that less than 10% of Weymouth's water supply comes via Old Swamp River to Whitman's Pond South Cove. How was this estimate reached? During winters that have heavy rains or snow, water is not pumped from Whitman's Pond South Cove. In the summer, Whitman's Pond South Cove supplies close to 40% of the Weymouth water supply. An average of 22-30% of Weymouth's yearly water supply is provided by Whitman's Pond South Cove. In addition, several municipal wells, specifically the Libby Park Well, are shown on Weymouth town maps as being located adjacent to Old Swamp River. How might these wells be influenced by contaminants in the river?
Response: ATSDR included additional information about Old Swamp River and the Weymouth water supply to the surface water and sediment exposure evaluation section of the PHA. Estimates regarding the percent of water from Old Swamp River that is used to supply water to Weymouth were based on previous studies of the water supply systems and discussions with the Weymouth water supply facility managers. A review of maps of the Weymouth water supply system and discussions with the Weymouth water supply facility manager did not identify groundwater supply wells along Old Swamp River. The four groundwater supply wells used by Weymouth are located along Mill River.
Comment: Information about the pathway French's Stream follows after leaving SWNAS was provided. The headwaters of French's Stream originate on the site, then flow southerly through Rockland and Hanover. During and after heavy rain, French's Stream floods over its banks throughout Rockland. There are several businesses along French's Stream that may be potential sources of additional contamination.
Response: Additional information regarding French's Stream was included in the PHA. Other potential contamination sources beyond the boundaries of SWNAS are also located along French's Stream. Businesses that may produce hazardous waste are regulated by state and federal regulations to ensure proper storage and disposal. If a release of hazardous materials or petroleum products does occur, the business owner or operator is required under state regulations to report this release to MADEP. MADEP then oversees necessary response actions and remedial activities. Unknown releases and contamination of the environment are mitigated by these regulations.
Comment: Old Swamp River is open for public recreational uses and may be stocked for fishing. A community member reports that fish are caught and eaten in large numbers. How might the high concentrations of antimony affect the fish population and humans consuming fish? Recreational exposures should be evaluated in more detail.
Response: ATSDR considered recreational use of Old Swamp River, including wading, canoeing, and fishing. Information about fish stocking was added to the PHA. Because no comparison values are available for surface water and sediment, drinking water and soil comparison values are used for evaluating these pathways. Drinking water and soil comparison values are derived using very conservative assumptions (protective of public health), such as assuming daily exposures. Actual exposures to surface water and sediment are expected to be much less frequent and of shorter duration. This information has been added to the evaluation of recreational exposures presented in the "Evaluation of Surface Water and Sediment Exposure Pathway" section of the PHA. No fish tissue samples were collected during the Phase I EBS and Phase I RI investigations. However, contaminants, specifically antimony, were detected in surface water and sediment above comparison values in only a small number of the samples collected. Fish are not expected to spend their entire life cycle within these contaminated areas. Therefore, bioaccumulation is not likely to be significant. The Phase II RI investigations include collecting and analyzing fish tissue samples. ATSDR will review these data, as necessary, when they become available.
Comment: ATSDR estimated that 50 people are likely to be exposed to surface water and sediment from Old Swamp River and French's Creek. This number seems low because Old Swamp River contributes to the Weymouth water supply. How was this estimate reached?
Response: ATSDR estimated that 50 to 500 people would potentially have direct and frequent contact with surface water and sediment while wading or canoeing in French's Stream and Old Swamp River. The actual number is expected to be closest to 50 people. Although Old Swamp River provides a portion of drinking water, drinking water is routinely tested for many contaminants based on the safe drinking water act. ATSDR reviewed potential exposure scenarios for people using French's Stream and Old Swamp River and concluded that the contaminants (arsenic, iron, and manganese) found above comparison values (health protective values) in surface water and sediment are below levels that may result in potential adverse health effects. This evaluation is presented in detail in the "Evaluation of Surface Water and Sediment Exposure Pathway" section of this PHA. To estimate the potentially exposed population, ATSDR evaluated the population density along Old Swamp River and French's Stream and the likely frequency and duration of stream use under site-specific conditions. ATSDR will also review new sampling data as becomes available.

Soil

Comment: If soil removal occurs and sale of this soil to the public is allowed, what measures will be taken to prevent exposure to hazards?
Response: The state regulations and the MCP outline strict guidelines that must be met for reuse of soil from potentially contaminated sites. These guidelines establish health-based standards for acceptable contaminant concentrations based on reuse at either industrial or residential sites. MADEP enforces these guidelines to ensure protection of public health and the environment.

Air

Comment: Although air quality was not listed as a community concern, there is strong community concern about air exposures from jets and airplanes flying overhead and from engine testing programs conducted at SWNAS.
Response: In response to concerns about past exposures to emissions from overhead aircraft and aircraft engine testing (flights by overhead aircraft and engine testing no longer occur at SWNAS.), ATSDR contacted EPA to obtain information about air emissions. EPA has performed extensive studies characterizing the emissions from aircraft engines and other related emissions sources at airports and military bases. Their studies include evaluations of the airport/military base specific impacts on human health and the environment. EPA estimates that aircraft engines contribute about 2 percent of nitrogen oxides (NOx) and carbon monoxide (CO) emitted by mobile source. However, in some airport areas, aircraft can contribute up to 4 percent of mobile source emissions. SWNAS was not one of EPA's study sites. At SWNAS, past aircraft flight practices and engine testing activities were conducted under standard operating procedures and federal and state permits required at that time. ATSDR has notified EPA's national contact for Aviation (aircraft) Emissions, Bryan Manning of community concerns regarding past exposure to engine emissions. Mr. Manning is available to answer questions and may be contacted at (734) 214-4832. Information on aircraft emission standards and other mobile sources is also available electronically on the Internet at EPA's Office of Mobile Sources website (http://www.epa.gov/OMSWWW). Additional information may also be obtained by mail at the following address:
Comment: Did ATSDR consider indoor air quality issues with regard to MCP sites? Many of the MCP sites have contaminants in groundwater that flow beneath buildings.
Response: In order to fully remediate a site under the MCP process, potential exposures to harmful levels of contamination must be prevented, including exposure to contaminants migrating to indoor air from the subsurface. At several MCP sites, petroleum products were released to soil located beneath a building foundation and the Navy was unable to remove the contaminated soil without compromising the building's integrity. At these locations, the Navy implemented Activity Use Limitations (AULs) with approval and oversight by MADEP. An AUL is a remediation tool under the MCP that specifies what future actions may be conducted at the site and what safety measures are required to prevent exposure. When implementing an AUL, the MCP requires that the Navy consider indoor air quality. Although indoor air quality data are not available, ATSDR believes that the MCP process and MADEP oversight are sufficient to prevent exposures through contaminant migration to indoor air from the subsurface.

Site History

Comment: The site history incorrectly states that the Squantum facility was previously at the current location of SWNAS. No marinas or seaplanes were present at SWNAS. What other jets and helicopters were stationed at SWNAS?
Response: The text has been revised to accurately reflect the historic flight use. During active operations from 1941 through 1997, various aircrafts were stationed at SWNAS, including blimps, piston-engine airplanes, turbo-propeller patrol airplanes, fighter jets, and helicopters.
Comment: Residents near West Gate Landfill report that this landfill also received medical wastes.
Response: Site records indicate that the West Gate Landfill received only incinerator ash from domestic waste. If the landfill did receive medical wastes, however, physical hazards would pose the greatest potential health hazards. ATSDR recommended that the Navy address physical hazards located throughout the site as part of redevelopment.
Comment: If PCBs were not manufactured until after SWNAS began operation in 1941 and DDT was widely applied before the 1960s, how can it not be known if background levels of metals, PCBs, pesticides, and semivolatile organic compounds (SVOCs) are a result of site operations or not?
Response: Many chemicals are ubiquitous in the environment and are considered to be present at background concentrations. These chemicals may be present from natural sources, such as metals in soil. Man-made or anthropogenic sources may also contribute to background concentrations. For example, pesticides were often applied over large areas of forests and swamps for pest control. Polyaromatic hydrocarbons, a class of SVOCs, are often the byproducts of combustion, including forest fires and vehicle exhaust. Chemicals may also be brought to a site in fill material. When evaluating potential health hazards at a site, ATSDR assesses exposures to all contaminants detected above comparison values, whether or not the contaminant was detected below background.
Comment: The land was a pristine wooded marshland before the SWNAS was constructed. Historical maps showing land use prior to SWNAS were provided to the groups conducting studies at the site.
Response: The PHA was modified to include this information.

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