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PUBLIC HEALTH ASSESSMENT

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


TABLES

Table 1.

Potential Exposure Pathways
Pathway NameSource of
Contamination
Environmental
Medium
Point of Exposure Route of
Exposure
Potentially Exposed Population Comment
Groundwater in the vicinity of SWNAS WGL
RDA
SL
FFTA
TLF
STP
ABTFSA
Background

(1,2-DCE, pesticides, and metals)

Groundwater Off-site private wells or future on-site wells Ingestion
Inhalation
Dermal
People using off-site private wells. It is not known how many people are using private wells or if any wells are contaminated.

Number of persons potentially exposed = 255 (based on 85 private wells within a 4 mile radius x 3 people living in each household.)

Past:
•The site has used municipal water since its inception. Thus, on-site exposure did not present a public health hazard. Levels of off-site exposures, if any, are unknown since there is no off-site sampling data and private well usage is unknown. It is doubtful that contamination is migrating off-site because only a small PCE plume has been found within site boundaries. This plume is located in the central portion of the site and no drinking water wells are or have been located within or proximate to the plume boundaries. The Navy is conducting remedial actions to treat groundwater and prevent further migration.

Present:
• The site uses municipal water, thus current on-site exposures do not present a public health hazard. At total of 53 active and 4 inactive private wells were identified within approximately 0.25 miles of SWNAS during ATSDR's review of town records and surveys. Of the active wells, 8 are potable, 11 have unknown uses, and the remaining 34 are non-potable (irrigation or monitoring). Available sampling data did not identify groundwater contamination migrating toward these private wells, however, private wells have not been sampled. Further environmental characterization of groundwater is ongoing.

Future:
• It is unlikely that future on-site exposures will pose a health hazard because regulations would require further investigations before the SWNAS aquifer can be considered a potential drinking water source.

Surface water and sediment in the vicinity of SWNAS Sediment:
WGL
RDA
FFTA
TLF
STP
ABTFSA
Background

(SVOCs, pesticides, and metals)

Surface water:
RDA
FFTA
TLF
STP
ABTFSA
Background

(SVOCs, pesticides, and metals)

Surface water and sediment
(French's Stream and Old Swamp River)
On-site and off-site surface water bodies Ingestion
Dermal
Town of Weymouth uses drinking water supplied by Old Swamp River. Trespassers using on-site surface water for recreation. Nearby residents using off-site surface water for recreation.
Number of potentially exposed persons = 50 to 500
Past:
• Although it is unknown whether any one was exposed to these surface water bodies and, if so, at what frequency and duration, if exposure did occur at current contaminant levels, it is unlikely to have resulted in adverse health outcomes.

Present:
• Exposures through recreational use are likely to be infrequent and of short duration both on and off site. Contaminant levels are not expected to present health hazards.
• Based on the overall lack of contaminants found in surface water from Old Swamp River and given that Old Swamp River supplies only a small percentage of Weymouth's total drinking water, exposure through the municipal water supply poses no apparent public health hazards.

Future:
• It is unlikely that future exposures will pose a health hazard because remedial activities should prevent future exposures. Therefore, no potential public health hazards were identified.

On-site surface and subsurface soil WGL
RDA
SL
FFTA
STP
ABTFSA
Soil On-site surface and subsurface soil Ingestion
Dermal
Current site residents and trespassers.

Numbers of potentially exposed persons = 50 to 500

Past:
• Trespassing at the air station was extremely limited because of security restrictions. On-site workers may have been in areas of contamination; however, remediation workers have proper protective equipment.
• Residents on the site were unlikely to contact the sources of contamination because the sites are located in restricted areas far from the Naval housing units.

Present:
• Although trespassing has increased since the site closed, access is still relatively limited. In addition, most soils at the sites are covered with natural vegetation. Exposures to soil are therefore likely to be infrequent and of short duration. Contaminant levels are not expected to present health hazards.
• Subsurface soil does not present a public health hazard because exposure to contamination below ground surface is unlikely.

Future:
• It is unlikely that future on-site exposures will pose a health hazard because remedial activities and/or use restrictions should prevent exposure to contamination.



WGL West Gate Landfill RDA Rubble Disposal Area
SL Small Landfill FFTA Fire Fighting Training Area
TLF Tile Leach Field STP Sewage Treatment Plant
ABTFSA Abandoned Bladder Tank Fuel Storage Area 1,2-DCE 1,2-dichloroethene
SVOC semivolatile organic compound    

Background locations are locations that have not been impacted by site contamination. Samples from background locations contain contaminants, such as metals, that are naturally occurring.

Table 2.

West Gate Landfill - Summary of Groundwater Monitoring Well Data That Exceed Comparison Values
Contaminant Frequency Detected
Above Comparison
Value1
Range of Detected
Concentrations
(ppb)
Drinking Water Comparison
Value (ppb)
child/adult Source
Metals
Arsenic 2/13

2.8 - 21.5

0.02
3/10
50
CREG
EMEG (Chronic)
MCL
Beryllium2 1/13 5 0.008
20/70
4
CREG
RMEG
MCL
Chromium 1/13 2.8 - 233 50/200 RMEG
Lead 1/13 2 - 61.2 15 EPA Action Level
Manganese 9/13 5.3 - 5,430 50/200 RMEG
Vanadium 1/13 2.5 - 174 30/100 EMEG
(Intermediate)

The data on Tables 2 through 11 are from Brown and Root, 1997. ATSDR also reviewed and considered additional data received in 1998 inelectronic format that includes additional CERCLA and MCP sites. This data confirmed but did not change ATSDR's conclusions about potential exposures and adequacy of safeguards to protect people identified in this report. ATSDR will review data from new sampling events in 1999, 2000 and 2001. Based on future data, ATSDR will evaluate if potential exposures remain safer than levels that would be expected to cause health effects and take steps necessary to work with stakeholders to protect public health.

Note: The following list of abbreviations applies to Tables 2 through 11.
CREG = Cancer Risk Evaluation Guide
EMEG = Environmental Media Evaluation Guide
LTHA = Lifetime Health Advisory for drinking water (EPA)
MCL = Maximum Contaminant Level
MCLG = Maximum Contaminant Level Goal
ppb = parts per billion
ppm = parts per million
RBC = Risk-Based Concentration
RMEG = Reference Dose Media Evaluation Guide

1 Number of samples with contaminant detected above comparison value / number of samples analyzed for the contaminant
2 Since the release of the public comment draft of this PHA, EPA withdrew the cancer slope factor for beryllium, which was used to derive the CREG. Therefore, ATSDR has also withdrawn the CREG. The previous CREG has been included in this PHA to maintain consistency with the public comment draft.

Note: The data presented in Tables 2 through 9 represent contaminant concentrations in samples collected from groundwater monitoring wells. These monitoring wells are for site characterization purposes only. Water from these wells is not used as drinking water and these data are not intended to represent concentrations that may be ingested from use of private wells.

Table 3.

Rubble Disposal Area - Summary of Groundwater Monitoring Well Data That Exceed Comparison Values
Contaminant Frequency Detected
Above Comparison
Value1
Range of Detected Concentrations
(ppb)
Drinking Water Comparison Value
(ppb)
child/adult Source
SVOCs
Bis(2-ethylhexyl)
phthalate
1/8

27

3 CREG
Metals
Arsenic 2/8 3.6 - 10.8 0.02
3/10
50
CREG
EMEG (Chronic)
MCL
Beryllium2 1/8 2.1 0.008
20/70
4
CREG
RMEG
MCL
Lead 1/8 1.9 - 43.4 15 MCL Action Level
Manganese 8/8 220 - 14,100 50/200 RMEG
Vanadium 1/8 50.5 30/100 EMEG (Intermediate)
Zinc 2/8 22.6 - 40,800 3,000/10,000 EMEG (Chronic)

Table 4.

Small Landfill - Summary of Groundwater Monitoring Well Data That Exceed Comparison Values
Contaminant Frequency Detected
Above Comparison
Value1
Range of Detected
Concentrations
(ppb)
Drinking Water Comparison Value
(ppb)
child/adult Source
Pesticides
Heptachlor epoxide

1/7

0.0061 0.004
0.1/0.5
0.2

CREG
RMEG
MCLG

Alpha Chlordane 1/7 0.033 0.03
6/20
0.2
CREG
EMEG (Chronic)
MCLG
Gamma Chlordane 1/7 0.032 0.03
6/20
0.2
CREG
EMEG (Chronic)
MCLG
Metals
Arsenic 1/7 2.6 0.02
3/10
50
CREG
EMEG (Chronic)
MCL
Beryllium2 5/7 0.31 -0.56 0.008
20/70
4
CREG
RMEG
MCL
Manganese 5/7 28.2 - 733 50/200 RMEG
Thallium 1/7 4.8 0.4 LTHA
Zinc 1/7 56 - 3,560 3,000/10,000 EMEG (Chronic)

Table 5.

Fire Fighting Training Area - Summary of Groundwater Monitoring Well Data That Exceed Comparison Values
Contaminant Frequency Detected
Above Comparison
Value1
Range of Detected
Concentrations
(ppb)
Drinking Water Comparison Value
(ppb)
child/adult Source
Metals
Antimony 3/9 23.7 - 27 4/10
6
RMEG
MCL
Arsenic 2/9 3.1 - 4.6 0.02
3/10
50
CREG
EMEG (Chronic)
MCL
Beryllium2 1/9 0.39 0.008
20/70
4
CREG
RMEG
MCL
Manganese 9/9 109 - 16,400

50/200

RMEG
Zinc 1/9 27.9 - 3,990 3,000/10,000 EMEG (Chronic)

Drinking Water Comparison Value
(ppb)

Table 6.

Tile Leach Field - Summary of Groundwater Monitoring Well Data That Exceed Comparison Values
Contaminant Frequency Detected
Above Comparison
Value1
Range of Detected
Concentrations
(ppb)
child/adult Source
Metals
Arsenic 3/4 3.2 - 15.3 0.02
3/10
50
CREG
EMEG (Chronic)
MCL
Beryllium2 4/4 0.98 - 5.7 0.008
20/70
4
CREG
RMEG
MCL
Lead 3/4 4.8 - 111 15 MCL Action Level
Manganese 4/4 108 - 1,110 50/200 RMEG
Vanadium 3/4 10.4 - 122 30/100 EMEG (Intermediate)

Table 7.

Sewage Treatment Plant - Summary of Groundwater Monitoring Well Data That Exceed Comparison Values
Contaminant Frequency Detected
Above Comparison
Value1
Range of Detected
Concentrations
(ppb)
Drinking Water Comparison Value (ppb)
child/adult Source
Metals
Manganese 3/3 108 - 4,270 50/200 RMEG

Table 8.

Abandoned Bladder Tank Fuel Storage Area - Summary of Groundwater Monitoring Well Data That Exceed Comparison Values
Contaminant Frequency Detected
Above Comparison
Value1
Range of Detected
Concentrations
(ppb)
Drinking Water Comparison Value
(ppb)
child/adult Source
Metals
Arsenic 1/4 3.6 0.02
3/10
50
CREG
EMEG (Chronic)
MCL
Beryllium2 4/4 0.68 - 1.2 0.008
20/70
4
CREG
RMEG
MCL
Manganese 4/4 56.2 - 533 50/200 RMEG
Vanadium 1/4 5.1 - 33.7 30/100 EMEG (Intermediate)

Table 9.

Perimeter Monitoring Well Summary Data
Contaminant Frequency Detected
Above Comparison
Value1
Range of Detected
Concentrations
(ppb)
Drinking Water Comparison Value (ppb)
child/adult Source
Metals
Aluminum 1/6 267 - 39,500 37,000
50
RBC
Secondary MCL
Arsenic 3/6 3.9 - 7.8 0.02
3/10
50
CREG
EMEG (Chronic)
MCL
Beryllium2 4/6 0.33 - 2.40 0.008
20/70
4
CREG
RMEG
MCL
Iron 2/6 341 - 36,600 11,000
300
RBC
Secondary MCL
Lead 2/6 1.7 - 24.50 15 MCL Action Level
Manganese 4/6 30.1 - 1,790 50/200
50
RMEG
Secondary MCL
Vanadium 2/6 6.3 - 71.1 30/100 EMEG (Intermediate)

Table 10.

Summary of Surface Water and Sediment Data From French's Stream That Exceed Comparison Values
Contaminant Frequency
Detected Above
Comparison Value1
Maximum
Detected
Concentration
Location of
Maximum
Concentration
Comparison Value (ppb)
child/adult Source
SURFACE WATER
SVOCs (ppb)
Bis(2-ethylhexyl)phthalate 2/20 6.0 FFTA 3 CREG
Pesticides (ppb)
4,4'-DDD 1/20 0.78 STP 0.1 CREG
4,4'-DDT 1/20 0.20 STP 0.1 CREG
Aroclor-1254 1/20 0.78 STP 0.2/0.7 RMEG
Metals (ppb)
Arsenic 3/21 3.2 STP 0.02 CREG
Beryllium2 2/21 14.7 ABTFSA 0.008
20/70
CREG
RMEG
Cadmium 1/21 3.4 ABTFSA 2/7 EMEG (Chronic)
Iron 2/21 272,000 ABTFSA 11,000 RBC
Lead 1/21 113.0 ABTFSA 15 MCL Action Level
Manganese 17/21 1,670 ABTFSA 50/200 RMEG
Vanadium 2/21 228 ABTFSA 30/100 EMEG (Intermediate)
SEDIMENT
SVOCs (ppb)
Benzo(a)anthracene 3/26 3,100 FFTA 870 RBC
Benzo(a)pyrene 7/26 2,600 FFTA 100 CREG
Benzo(b)fluoranthene 4/26 1,300 FFTA 870 RBC
Dibenz(a,h)anthracene 3/26 220 STP 87 RBC
Indeno(1,2-c,d)pyrene 1/26 940 FFTA 870 RBC
Pesticides (ppb)
Dieldrin 2/26 560 STP 40 CREG
Metals (ppm)
Arsenic 26/27 22 STP 0.5 CREG
Beryllium2 7/27 1.4 FFTA 0.008
100/1000
CREG
RMEG
Iron 2/27 44,900 WGL 23,000 RBC

Table 11.

Summary of Surface Water and Sediment Data From Old Swamp River That Exceed Comparison Values
Contaminant Frequency
Detected Above
Comparison Value1
Maximum
Detected
Concentration
Location of
Maximum
Concentration
Comparison Value (ppb)
child/adult Source
SURFACE WATER
Metals (ppb)
Antimony 1/13 17.5 Background 4/10 RMEG
Arsenic 1/13 1.8 RDA 0.02 CREG
Iron 1/13 16,600 RDA 11,000 RBC
Manganese 13/13 3,570 RDA 50/200 EMEG (intermediate)
Thallium 1/13 5.2 RDA 0.4 LTHA
SEDIMENT
SVOC (ppb)
Benzo(a)anthracene 3/13 1,500 RDA 870 RBC
Benzo(a)pyrene 9/13 1,600 RDA 100 CREG
Benzo(b)fluoranthene 5/13 2,400 RDA 870 RBC
Dibenz(a,h)anthracene 3/13 230 RDA 87 RBC
Pesticide
Dieldrin 1/7 55 RDA 40 CREG
Aroclor-1260 1/7 23,000 RDA 400 CREG
Metals (ppm)
Arsenic 12/13 8.9 Background 0.02 CREG
Iron 4/13 45,500 RDA 23,000 RBC



FIGURES


Figure 1. Site Map and Demographics


Figure 2. SWNAS, SNAS, and Nomans Land Island Relative Location Map


Figure 3. IRP and MCP Site Locations


Figure 4. USCG Site Locations


Figure 5. ATSDR's Exposure Evaluation Process


Figure 6. Weymouth, Hingham, Rockland,
and Abington Boards of Health Survey of Wells


Figure 7. Weymouth, Hingham, Rockland,
and Abington Townships Orthophoto



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