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1. ATSDR > Public Health Assessments & Consultations

PUBLIC HEALTH ASSESSMENT

NAVAL AIR WARFARE CENTER
[a/k/a NAVAL AIR DEVELOPMENT CENTER (8 WASTE AREAS)]
WARMINSTER TOWNSHIP, BUCKS COUNTY, PENNSYLVANIA

CONCLUSIONS

On the basis of its evaluation of available environmental information, ATSDR concluded that exposures to contaminants in groundwater, surface soil, surface water, and sediment at NAWC are below levels that cause adverse health effects. Because exposure to low levels of contamination is possible, ATSDR has categorized this site as no apparent public health hazard. In evaluating exposures to contaminants found in one off-site municipal water supply system and exposures to lead in paint, dust, and soil in homes, ATSDR concluded that these exposures posed an indeterminate health hazard (definitions of categories are provided in the glossary in Appendix E). Conclusions regarding media- and site-specific exposures are as follows.

1. Using site-specific exposure assumptions, ATSDR determined that no public health hazards are associated with exposures to contaminants in groundwater from NAWC water supply wells or off-site municipal wells. In each instance, no adverse health effects to adults or children would be expected because the contaminant exposure concentrations have been too low. Possible health effects resulting from exposures to contaminants found in one off-site municipal water supply system prior to 1979, however, were indeterminate because information about contaminants and concentrations leading to well closures are unknown. Since contaminants were detected in groundwater in 1979, measures, such as installation of treatment systems on supply wells and installation of groundwater treatment systems at source locations, have been taken to reduce or eliminate exposure. In accordance with the RODs for NAWC, the Navy also conducts regular monitoring.



2. Based on a review of available data, ATSDR has concluded that past, current, and future exposures to contaminants through use of private wells by adults or children in neighborhoods surrounding NAWC are too low to result in illness or other adverse health effects. Since contaminants were first detected in private wells in 1993, measures to reduce or eliminate exposures have been implemented. These measures included installation and operation of treatment systems in homes and connection of homes to municipal water supplies.



3. No public health hazards were identified when assessing the potential for subsurface contamination to migrate from the Site 5 landfill to housing units in Shenandoah Woods. Groundwater, soil gas, and indoor air samples contained contaminants at levels below health concern. In Casey Village, VOCs in groundwater may migrate to indoor air. EPA and PADEP are conducting ongoing investigations in this neighborhood and may be contacted for additional information.



4. No public health hazards are associated with exposures to surface soils at NAWC. Surface-soil contamination was investigated at eleven sites located throughout NAWC. Ten sites were located near research and industrial facilities or airfields where access was restricted to base personnel. Base personnel were expected to wear long pants, work gloves, and work boots to further prevent past exposures. One site, Site 5, is located in an on-base housing complex, Shenandoah Woods. ATSDR evaluated exposures at this site and considered concentrations detected, exposure parameters, and toxicity information. Doses estimated during this exposure assessment were below levels reported in the toxicology literature as likely to result in adverse health effects to adults and children. For each of the areas of soil contamination, the Navy has signed RODs selecting necessary remedial actions to prevent current and future exposures based on current land use and proposed redevelopment plans.



5. Considering concentrations detected, exposure parameters, and toxicity information, ATSDR determined that exposures to contaminants in surface water and sediment from streams draining NAWC pose no public health hazards. Doses estimated during this exposure assessment were below those reported in the toxicology literature as likely to result in adverse health effects. Exposures via wading or playing are expected to be infrequent and of short duration as the streams are intermittent. These streams do not support a fish population viable for human consumption. The Navy completed remedial actions for groundwater and soil to remove potential contamination sources. The Navy also monitors groundwater wells and operates groundwater treatment systems to track contaminant movement and prevent future exposures, including exposure through groundwater discharge to surface water. Under RODs for NAWC, the Navy will conduct ongoing monitoring in Areas A and B. No further action is planned for Area C.



6. Based on a detailed evaluation of possible adverse health effects from past, current, and future exposures to lead in on-base housing, ATSDR concluded that past exposure to lead was not expected to result in adverse health effects in all homes except one. In one home, lead exposures could have resulted in increased blood lead levels, however, possible adverse health effects are indeterminate because it is unknown if children and pregnant women lived in this home when lead was accessible.

RECOMMENDATIONS

ATSDR recommends that the following actions be taken to ensure continued protection of public health at NAWC and in surrounding communities.

1. If data from groundwater and water supply monitoring identifies increased chemical concentrations, new chemicals, or new potential source areas, ATSDR requests that the Navy, EPA, and PADEP notify ATSDR and PADOH. If, after evaluation, the information changes the current PHA findings, ATSDR will then make appropriate public health recommendations.



2. As a prudent public health measure, ATSDR recommends that private well users periodically test (every 1 to 2 years) their wells because groundwater conditions can change over time and unidentified sources may exist in the area. Regular maintenance and testing of private wells with treatment systems is especially important to ensure proper operation of these systems. As a general health consideration, private wells users should also regularly sample their wells for bacteria content, particularly at the point of use.



3. ATSDR requests Navy notification if, in operation and maintenance of the Shenandoah Woods housing complex, the Navy identifies concerns about gases released from the Site 5 landfill or if information regarding contamination at Shenandoah Woods changes. ATSDR also requests that EPA and PADEP inform ATSDR about the results of ongoing investigations in Casey Village and other areas.



4. ATSDR conducted evaluations of surface soil exposures based on past, current, and proposed future land uses. However, if proposed land uses and potential exposures change, the likelihood of human exposure should be re-evaluated by the Bucks County Health Department, PADEP, EPA, Navy, or ATSDR.



5. If new data from stream monitoring conducted under the RODs identifies increased chemical concentrations or new chemicals, ATSDR requests that the Navy, EPA, and PADEP notify ATSDR and PADOH. If, after evaluation, the information changes the current PHA findings, ATSDR will then make appropriate public health recommendations.



6. ATSDR will seek information from the Navy about occupants of Quarters A during the time lead was accessible to further evaluate possible lead exposures.

PUBLIC HEALTH ACTION PLAN

The Public Health Action Plan (PHAP) for NAWC contains a description of actions taken and those to be taken by the ATSDR, Navy, EPA, PADEP, and Bucks County Health Department at and in the vicinity of the base subsequent to the completion of this PHA. The purpose of the PHAP is to ensure that this PHA not only identifies potential and ongoing public health hazards, but provides a plan of action designed to mitigate and prevent adverse human health effects resulting from exposure to hazardous substances in the environment. The public health actions that are completed, being implemented, or planned are listed below.

Completed Actions

Groundwater

1. Use of on-base wells with contamination was discontinued when contamination was first discovered in 1979. In 1993, the Navy identified and sampled municipal, commercial, and residential wells in the vicinity of NAWC. As a result of sampling, affected homes and potentially affected homes were connected to municipal water supplies or wells were connected to treatment systems. As part of the site remediation, groundwater treatment systems have been installed at source locations.

Soil

2. The Navy removed contaminated soil and debris at Site 4 between December 1996 and July 1997. The area was backfilled with clean material. The Navy also completed removal actions for contaminated soil at Sites 1, 2, 3, and 6 in 1998 and at Site 8 in 1999. In all instances, the Navy disposed of contaminated soil in a permitted off-site disposal facility.

Lead Paint

3. The Navy completed removal and abatement actions at homes containing lead paint, including homes in the officer housing area, Quarters A, and Quarters B. Lead paint was either removed or encapsulated, lead paint chips found at the foundation of residences were removed, and areas where lead concentrations in soil exceeded standards were remediated.

Ongoing and Planned Actions

Groundwater

1. The Navy operates groundwater treatment systems to remove VOCs at source locations and monitors groundwater throughout NAWC to track contaminant movement. Treatment systems and monitoring were selected as the most appropriate interim remedial actions under RODs for OUs 1, 3, and 4. Ongoing treatment and monitoring will likely be selected as the final remedial action. In addition to ongoing treatment, the ROD for OU4 includes institutional controls to prevent supply well use and installation without proper treatment systems and approval by state and local authorities.



2. NAWC and surrounding municipalities regularly sample their water supply wells to ensure the safety of the drinking water supply.



3. Several municipal drinking water supplies surrounding NAWC have been affected by regional groundwater contamination and off-base sources. PADEP and EPA continue to investigate potential sources and address the regional groundwater contamination problem. Local municipalities and PADEP monitor water supplies to ensure that contamination does not compromise public health.



4. The Navy plans to organize and map available groundwater data, including chemical contamination locations and pressures and levels of ground and surface water. This information, combined with information from other potentially responsible parties, will be shared with area stakeholders, such as PADEP, PADOH, EPA, water suppliers, and residential well owners, to support wellhead protection programs, to increase the understanding of groundwater contamination, and to ensure continued protection of public health.

Surface Water/Sediment

5. Under RODs for NAWC, the Navy will monitor streams in Areas A and B to track contaminant movement and ensure that no elevated contaminant levels leave the base.

PREPARERS OF REPORT

This report was prepared under the direction and supervision of the following individuals:

Charles Grosse, M.S., REM
Environmental Health Scientist
Federal Facilities Assessment Branch
Division of Health Assessment and Consultation

Gary Campbell, Ph.D.
Environmental Health Scientist
Federal Facilities Assessment Branch
Division of Health Assessment and Consultation

Assistance in the preparation of this report was provided by:

Thomas R. Stukas
Regional Representative
ATSDR Regional Office (Region III)

Sarah N. Dun, M.S.
Public Health Scientist
Eastern Research Group, Inc.

REFERENCES

Agency for Toxic Substances and Disease Registry (ATSDR). 1992. Draft Site Summary Report, Naval Air Development Center (NADC), Warminster, Pennsylvania from the Health Assessment Activities at the Department of Defense National Priorities List Sites for FY91 (Draft). March 1992.

ATSDR. 1997a. Toxicological profile for polychlorinated biphenyls. Atlanta, GA: Agency for Toxic Substances and Disease Registry. September 1997.

ATSDR. 1997b. Toxicological profile for tetrachloroethylene. Atlanta, GA: Agency for Toxic Substances and Disease Registry. September 1997.

ATSDR. 1997c. Toxicological profile for trichloroethylene. Atlanta, GA: Agency for Toxic Substances and Disease Registry. September 1997.

ATSDR. 1998a. Toxicological profile for arsenic. Atlanta, GA: Agency for Toxic Substances and Disease Registry. August 1998.

ATSDR. 1998b. Toxicological profile for chromium. Atlanta, GA: Agency for Toxic Substances and Disease Registry. August 1998.

ATSDR. 1999a. Health Consultation, Derewal Property, Warminster, Bucks County, Pennsylvania, CERCLIS No. PA0000076224. May 5, 1999.

ATSDR. 1999b. Toxicological profile for lead. Atlanta, GA: Agency for Toxic Substances and Disease Registry. July 1999.

Ambler Laboratories. 1979. Correspondence to the Warminster Municipal Township Authority Re: Well 26 TCE Contamination. September 28, 1979.

Ames, T. 1998. Personal communication with Thomas Ames, Base Environmental Coordinator, NAWC Warminster. May 7, 1998, July 30, 1998, and November 20, 1998.

Ames, T. 1999. Personal communication with Thomas Ames, Base Environmental Coordinator, NAWC Warminster. February 18, 1999 and March 10, 1999.

Ames, T. 2000. Personal communication with Thomas Ames, Base Environmental Coordinator, NAWC Warminster. April 18, 2000 and May 3, 2000.

Analytical Laboratories, Inc. 1997. Correspondence to the Warminster Municipal Township Authority Re: Well 26 Sample Analysis Report. January 1997.

Brown & Root Environmental Corporation (Brown & Root). 1996a. Site 6 Removal Evaluation Report, Naval Air Warfare Center, Warminster, Pennsylvania. July 1996.

Brown & Root. 1996b. Interim Remedial Investigation Report for Operable Unit 4, NAWC Warminster. October 1996.

Brown & Root. 1996c. Phase III Remedial Investigation Report (Media Other Than Groundwater), NAWC Warminster. November 1996.

1990 Census of Population and Housing. 1991. Summary Tape Files 1A and 1B (Pennsylvania) [machine-readable data files]. Prepared by the Bureau of Census. Washington, DC: The Bureau [producer and distributor], 1991.

2000 Census of Population and Housing. 2000. Summary Tape Files 1 (Pennsylvania). Prepared by the Bureau of Census. Washington, DC, 2000.

Department of the Navy. 1993. Record of Decision, Naval Air Development Center (OU1). September 30, 1993.

Department of the Navy. 1994. NAWC Warminster Fact Sheets No. 1 to 5. March 1994-July 1996.

Department of the Navy. 1995. Record of Decision, Naval Air Development Center (OU3). March 9, 1995.

Department of the Navy. 1996. Draft Environmental Impact Statement, Disposal and Reuse, Naval Air Warfare Center, Aircraft Division, Warminster, Pennsylvania. December 1996.

Department of the Navy. 1997a. Lead Management Plan, Senior Enlisted Quarters, Naval Air Station Joint Reserve Base Willow Grove. January 1997.

Department of the Navy. 1997b. Record of Decision, Naval Air Development Center (OU4). September 30, 1997.

Department of the Navy. 1997c. Consensus Document, No Further Action For Site 4, Draft. October 1997.

Department of the Navy. 1999. Record of Decision for OU5 (Site 8). September 1999.

Department of the Navy. 2000a. Record of Decision for OU6 (Soil, Surface Water, and Sediment Associated with Site 4). April 2000.

Department of the Navy. 2000b. Record of Decision for OU7 (Soil ans Waste at Sites 6 and 7). June 2000.

Department of the Navy. 2000c. Record of Decision for OU8 (Soils in Area D). June 2000.

Department of the Navy. 2000d. Record of Decision for OU9 (Area A Soils, Surface Water, and Sediment). June 2000.

Department of the Navy. 2000e. Record of Decision for OU10 (Site 5 Soils and Area B Surface Water and Sediment). September 2000.

EA Engineering, Science, and Technology, Inc. (EA Engineering). 1995. Basewide Environmental Baseline Survey, Naval Air Warfare Center, Aircraft Division, Warminster, Pennsylvania, Final. March 25, 1995.

Feeney, J. 2000. Personal communication with James Feeney, EPA Remedial Project Manager for Fischer & Porter Company site. October 20, 2000.

Fischer & Porter Company. no date. Record of Decision, Fischer & Porter Company Site, Decision Summary.

Foster Wheeler Environmental Corporation (Foster Wheeler). 1998. Close-Out Report, Various Source Removal Sites, Naval Air Warfare Center. August 1998.

Gold, P. 1999. Personal communication with Pete Gold, EPA Site Assessment Manager for Casey Village. May 26, 1999.

Halliburton NUS. 1992. Phase II Remedial Investigation Report, NAWC Warminster. November 1992.

Halliburton NUS. 1993a. Phase II Remedial Investigation Report for Operable Unit 1, NAWC Warminster. April 1993.

Halliburton NUS. 1993b. Off-base Well Inventory and Sample Analysis Report for NAWC Warminster. September 1993.

Halliburton NUS. 1994a. Community Relations Plan for Naval Air Warfare Center Aircraft Division, Warminster. March 1994.

Halliburton NUS. 1994b. Remedial Investigation Report for Operable Unit 3, NAWC Warminster. August 1994.

Halliburton NUS. 1995. Site 4 Engineering Evaluation and Cost Analysis Report for NAWC, Warminster, Pennsylvania.

Hunter, M. 1998. Personal communication with Mike Hunter, Base Environmental Engineer, NAWC Warminster. May 7, 1998.

NUS Corporation. 1985. Preliminary Assessment and Site Inspection of the Naval Air Development Center. June 7, 1985.

Ostrauskas, D. 1999. Personal communication with Darius Ostrauskas, EPA Remedial Project Manager for NAWC. June 1 and December 9, 1999.

Ostrauskas, D. 2000. Personal communication with Darius Ostrauskas, EPA Remedial Project Manager for NAWC. October 13, 2000.

Pennsylvania Department of Health (PADOH). 1981. Warminster Area Birth Defects Within Normal Levels. January 27, 1981.

PADOH. 1999. Health Consultation, Fischer & Porter Company. Completed under a Cooperative Agreement with ATSDR. March 15, 1999.

Pursel, A. 1998. Personal communication with Atwood Pursel, Jr., Manger at the Upper Southampton Municipal Water Authority. October 22, 1998.

Pursel, A. 1999. Personal communication with Atwood Pursel, Jr., Manager at the Upper Southampton Municipal Water Authority. June 16, 1999.

Smith, G. 1998. Personal communication with Geoff Smith, Manager at the Warminster Municipal Water Authority. October 19, 1998.

Smith, G. 1999. Personal communication with Geoff Smith, Manager at the Warminster Municipal Water Authority. June 16, 1999 and December 6, 1999.

Szamborski, N. 1998. Personal communication with Nancy Szamborski, Housing Director, NAWC Warminster. May 5, 1998.

Szamborski, N. 1999. Personal communication with Nancy Szamborski, Housing Director, NAWC Warminster. March 10 and 31, 1999.

Tetra Tech NUS, Inc. 1999a. Remedial Investigation Operable Unit 7 (OU7) Soils and Waste at Sites 6 and 7, Former Naval Air Warfare Center, Warminster, Pennsylvania. November 1999.

Tetra Tech NUS, Inc. 1999b. NAWC Warminster Environmental GIS Layer, Release 2.0. December 1999.

Tetra Tech NUS, Inc. 2000a. Restoration Advisory Board (RAB) Meeting Minutes, Former Naval Air Warfare Center (NAWC) Warminster, Pennsylvania. August 5, 1999 through February 3, 2000.

Tetra Tech NUS, Inc. 2000b, Record of Decision (ROD) for Operable Unit 6 (OU6), Former Naval Air Warfare Center, Warminster, Pennsylvania. April 2000.

Tetra Tech NUS, Inc. 2000c, Remedial Investigation/Feasibility Study (RI/FS) for Operable Unit 9 (OU9) (Area A Media Other Than Groundwater) for Naval Air Warfare Center, Warminster, Pennsylvania. April 2000.

U.S. Environmental Protection Agency (EPA). 1999. Safe Drinking Water Act Information System search at http://www.epa.gov/enviro/html/sdwis/sdwis_query.html . March 1999.

United States Geological Survey (USGS). 1998. Geohydrology and Distribution of Volatile Organic Compounds in Groundwater in the Casey Village Area, Bucks County, Pennsylvania. 1998.

Warminster Township. 1999. Zoning Map, Warminster Township, Bucks County, Pennsylvania. November 1999.

TABLES

Table 1: Population and Housing Data Table

Population Data	Site Area*	Bucks County
Total persons	28.937	597,635
Total area, square miles	19.99	607.64
Persons per square mile	1,448	984
Percent male	48.9	49.1
Percent female	51.1	50.9
Percent white	90.7	92.5
Percent black or African American	3.3	3.3
Percent American Indian, Alaska Native or Aleut	0.1	0.1
Percent Asian, Native Hawaiian, or other Pacific Islander	2.2	2.3
Percent other races or two or more races	3.6	1.8
Percent Hispanic origin	4.9	1.8
Percent under age 10	14.5	13.6
Percent 65 and older	12.5	12.4

Source: Census of Population and Housing, 2000: Summary File 1 (Pennsylvania)

* Census tracts 1016.03, 1016.05, 1016.07, 1016.08, 1016.09, 1017, 1049.02 and 1050.08 in Bucks County, Pennsylvania

Table 1: Population and Housing Data Table

Housing Data	Site Area*	Bucks County
Households	10,418	218,725
Persons per household	2.76	2.69
Percent households owner-occupied	72.8	77.4
Percent households renter-occupied	27.2	22.6
Percent households mobile homes #	0.1	2.8
Percent persons in group quarters	0.8	1.5
Median value, owner-occupied households #	147,600	140,000
Median monthly rent, renter-occupied households #	449	524

Source: Census of Population and Housing, 2000: Summary File 1 (Pennsylvania)

# From U.S. Census Bureau, 1990 Census of Population and Housing, 1990: Summary Tape File 1 (Pennsylvania)

* Census tracts 1016.03, 1016.05, 1016.07, 1016.08, 1016.09, 1017, 1049.02 and 1050.08 in Bucks County, Pennsylvania

Table 2: Completed Exposure Pathways at NAWC Warminster

	Exposure Pathway Elements
Pathway Name	Contaminant	Environmental Medium	Point of Exposure	Route of Exposure	Time of Exposure	Exposed Population	Comments
Groundwater (On-base NAWC water supply wells)	volatile organic compounds (VOCs) (primarily tetrachloro-ethylene [PCE] and trichloro-ethylene [TCE])	groundwater	Naval Air Warfare Center (NAWC) water supply system	ingestion, inhalation, dermal (skin) contact	past, current, future	On-base workers and residents (In the past, as many as 3,300 workers and 25 residents were at NAWC. Currently, 500 workers and 25 residents are at NAWC.)	Past: No public health hazards were identified. The Agency for Toxic Substances and Disease Registry (ATSDR) assessed potential exposure doses based on the maximum detected contaminant concentrations and conservative assumptions about how often and how long a person might contact contaminants. The estimated exposure doses were below those reported in the toxicology literature to result in potential adverse health effects. Current/Future: No public health hazards were identified. The three NAWC wells with contamination are no longer used as a drinking water supply. In addition, the Navy implemented source control measures (groundwater treatment and soil removal) and monitors contaminant migration.
Groundwater (Off-base municipal supply wells and off-base private wells)	VOCs (primarily PCE and TCE) and arsenic	groundwater	Well 26 of the WMWA supply system and private wells in Ivyland/Kirk Road neighborhood	ingestion, inhalation, dermal (skin) contact	past, current, future	Off-base residents (WMWA serves 40,000 area residents. An estimated 155 people in Ivyland/ Kirk Road use private well water.)	Past: No public health hazards were identified. ATSDR assessed potential exposure doses based on the maximum detected contaminant concentrations and conservative assumptions about how often and how long a person might contact contaminants. The estimated exposure doses were below those reported in the toxicology literature to result in potential adverse health effects. Current/Future: No public health hazards were identified. The Navy connected homes to municipal water supplies or installed groundwater treatment systems. WMWA installed a treatment system on Well 26. In addition, the Navy implemented source control measures (groundwater treatment and soil removal) and monitors contaminant migration.
Surface soil (Soil contamination sites in restricted areas)	polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dioxins, and metals	surface soil	Restricted Areas of NAWC Area A (Sites 1, 2, 3, and Impoundment Area), Area B (Sites 6 and 7), and Area C (Sites 4, 8, Maintenance Area, and Tile Field)	incidental ingestion and dermal (skin) contact	past	On-base workers (In the past, as many as 3,300 workers were at NAWC. Currently, 500 workers are at NAWC.)	Past: No contamination above comparison values (CVs) was detected at Site 7 and the Tile Field. Infrequent and incidental contact with contaminants in surface soil is unlikely to pose a public health hazard. In addition, workers are expected to have worn proper protective equipment, such as long pants, work gloves, and work boots. Current/Future: NAWC was closed under the Base Realignment and Closure (BRAC) program in 1996 and is no longer accessed daily by site workers. Removal actions have been completed at Sites 1, 2, 3, 4, and 6. The Navy is remediated other sites as necessary to prevent future exposures.
Surface Soil (Soil contamination sites located in the Shenandoah Woods housing complex)	Aroclor-1254, benzo(a)pyrene, cadmium, and lead	surface soil	Shenandoah Woods housing complex Area B (Site 5)	incidental ingestion and dermal (skin) contact	past, current, and future	On-base residents (An estimated 550 residents live in this housing complex.)	Past/Current/Future: Sampling detected contaminants above CVs in only a small number of samples collected. Incidental contact with these contaminants is unlikely to pose a public health hazard based on an evaluation of potential exposures.
Surface water and sediment (Areas A, B, and C)	chloromethane, PCE, PAHs, and metals in surface water PAHs, PCBs, pesticides, and metals in sediment	surface water and sediment	drainage channels and tributaries in Areas A, B, and C associated with Little Neshaminy Creek and Southampton Creek	incidental ingestion and dermal skin contact	past, current, and future	on- and off-base residents (There are an estimated 575 on-base and 8,500 off-base residents.)	Past/Current/Future: Infrequent exposure during recreational use by residents is unlikely to pose a public health hazard based on an evaluation of exposure doses. Streams and drainage channels at NAWC and immediately down stream have insufficient flow to support a fish population.
Lead paint (Officer Housing Units and Quarters A and B)	lead	paint, dust, and soil	Officer Housing units and Quarters A and B	incidental ingestion	past, current, and future	NAWC residents (Quarters with lead paint house 25 residents.)	Past: Damaged lead paint was found in less than 10% of the inspection points in each of eight homes found containing lead paint. Lead exposure would have been infrequent. Only Quarters A had lead in dust and soil samples above standards. Lead exposures in this home could have resulted in increased blood lead levels. It is unknown, however, if children or pregnant woman (the most vulnerable populations) resided in these homes. Possible adverse health effects, therefore, are indeterminate. Current/Future: The Navy completed remedial actions at the officer housing area and Quarters A and B to prevent current and future exposures.

Table 3: Completed Exposure Pathways from Water Supplies Affected by Off-Base Sources

	Exposure Pathway Elements
Pathway Name	Contaminant	Environmental Medium	Point of Exposure	Route of Exposure	Time of Exposure	Exposed Population	Comments
Groundwater (Off-base municipal wells affected by off-base sources)	volatile organic compounds (VOCs) (primarily tetrachloro-ethylene [PCE] and trichloro-ethylene [TCE])	groundwater	Upper Southampton Municipal Water Authority (SMWA) and Hatboro Water Authority (HWA) municipal water supply wells	ingestion, inhalation, dermal (skin) contact	past, current, future	Off-base residents (SWMA supplies water to 13,000 people and HWA supplies water to18,900 people.)	Past: The Agency for Toxic Substance and Disease Registry (ATSDR) determined that concentrations detected in the SMWA wells were unlikely to cause harmful effects. ATSDR was unable to evaluate past exposures to contaminants in the HWA wells because necessary information was unavailable. Current/Future: No health hazards were identified. The municipal water authorities regularly monitor the water supply under state and local regulations.
	VOCs (primarily PCE and TCE)	groundwater	WHDC municipal water supply wells	ingestion, inhalation, dermal (skin) contact	past, current, future	Off-base residents (WHDC supplies water to 3,100 people.)	The Pennsylvania Department of Health (PADOH) completed a Health Consultation in March 1999. They conclude that while past exposures occurred, the wells no longer pose a public health hazard because WHDC wells are treated and monitored under state and local regulations. PADOH also concluded that no increase in risk for cancer exists due to exposure to VOCs in the contaminated water supply.
Groundwater (Off-base private wells affected by off-base sources)	VOCs (primarily PCE and TCE)	groundwater	Private wells in Speedway, Flying Heels, and Casey Village	ingestion, inhalation, dermal (skin) contact	past, current, future	Off-base residents (An estimated 130 people in Speedway, 240 people in Flying Heels use private well water. In the past, 215 Casey Village residents used private well water; these homes are now connected to the municipal supply.	Past: No public health hazards were identified. ATSDR determined that concentrations detected are unlikely to cause harmful effects. Current/Future: No public health hazards were identified. The Navy connected homes to municipal water supplies or installed groundwater treatment systems. In addition, the Navy monitors contaminant migration to prevent future contamination of wells.

Table 4: NAWC Past and Current Water Supply Wells

Well	Use	Comments
1 and 2	Fire Protection	Wells 1 and 2 contributed to the main drinking water supply system from the early 1940s until 1979 and were blended with water from Wells 3, 4, and 10. Wells 1 and 2 were closed in 1979 due to VOC contamination.
3, 4, and 10	Active	These wells supply the majority of the potable water at NAWC. Water from these wells is pumped into a large holding tank and blended prior to distribution. After base closure, Well 10 will be incorporated into the Warminster municipal water supply.
5	Closed	Well 5 provided drinking water to the officers quarters located along Jacksonville Road. Well 5 was closed in 1979 due to VOC contamination. This well is no longer used for any purpose.
6 and 7	Inactive	Well 6 is an inactive well that served Building 80, which is no longer in use. Well 7 is an inactive well that served Quarters A, which currently receives water from the municipal water supply. Both Wells 6 and 7 could be reactivated if needed.
8 and 9	Active	Wells 8 and 9 are currently active and serve Quarters B and Building 115, respectively.

Source: NUS Corporation 1985; Halliburton NUS 1992; EA Engineering 1995; Ames 1999; Smith 1999.

Table 5: Summary of Past Data That Exceeded Comparison Values in Off-Base and On-Base Drinking Water Wells

Chemical	Range of Detected Concentrations (ppb)1	Frequency of Detection2	Comparison Value (ppb)	Source
On-Site Supply Wells 1, 2, and 5   Halliburton NUS 1993a
PCE	36	unknown	5	MCL
TCE	293	unknown	5	MCL
Off-Site Municipal Supply Wells, WMWA Well 26 Halliburton NUS 1993a; Ambler Laboratories 1979
PCE	17	1/1	5	MCL
TCE	67.8	1/1	5	MCL
Arsenic	3.7	1/1	0.02 50	CREG MCL
Off-Site Private Wells, Area 1 North (Ivyland/Kirk Road) Halliburton NUS 1993a, 1993b
PCE	0.2 - 31	14/51	5	MCL
Arsenic	4.6	1/1	0.02 50	CREG MCL3

Sources: Halliburton NUS 1993a, 1993b; Ambler Laboratories 1979.

Notes:

¹The listed concentrations were detected when the wells were active. A single value is presented when the range of detections is unknown or the contaminant was detected in only one sample.
²Frequency of detection is the times sought/times detected
³EPA is currently considering lowering the MCL for arsenic to between 10 and 20 ppb.

Table 6: Summary of Data that Exceed Comparison Values for Water Supplies Affected by Off-Base Sources

Chemical	Range of Detected Concentrations (ppb)1	Frequency of Detection2	Comparison Value (ppb)	Source
Off-Site Private Wells, Area 1 South (Speedway)
PCE	0.3 - 6	3/37	5	MCL
TCE	46	1/37	5	MCL
Off-Site Private Wells, Area 2 West (Flying Heels)
TCE	3 - 6	3/73	5	MCL
Off-Site Private Wells, Area 2 East (Casey Village)
PCE	0.1 - 480	30/74	5	MCL
TCE	0.1 - 1,200	34/74	5	MCL
1,1-DCE	0.1 - 19	20/74	7	MCL
cis-1,2-DCE	0.4 - 530	21/74	70	MCL
Carbon tetrachloride	6.9 - 8.7	2/74	5	MCL

Sources: Halliburton NUS 1993b

Notes:

¹The listed concentrations were detected when the wells were active. A single value is presented when the contaminant was detected in only one sample.
²Frequency of detection is the times sought/times detected.

Table 7: Summary of Surface Soil Data That Exceed Comparison Values

Chemical	Range of Detected Concentrations (ppm)1	Frequency of Detection2	Comparison Value (ppm)	Source
OU1, Area A, Site 2
Benzo(a)pyrene	0.3 - 3.4	44/64	0.1	CREG
Antimony	0.19 - 842	52/106	300	RMEGadult
Arsenic	0.88 - 22.8	56/56	0.5	CREG
Lead	8 - 80,800	112/112	400	EPA SSL
OU1, Area A, Site 3 (burn pit)
Benzo(a)pyrene	0.052 - 3.4	25/31	0.1	CREG
OU1, Area C, Site 4 (north runway landfill)
Benzo(a)anthracene	0.079 - 0.87	13/144	0.87	RBC
Benzo(a)pyrene	0.046 - 0.7	6/144	0.1	CREG
Benzo(b)fluoranthene	0.058 - 1.1	18/144	0.87	RBC
Dibenzo(a,h)anthracene	0.069 - 0.088	2/144	0.087	RBC
OU1, Area B, Site 5 (south runway landfill and Shenandoah Woods housing complex)
Aroclor-1254	0.02 - 24	19/36	1	EMEGchild
Benzo(a)pyrene	0.067 - 0.27	3/29	0.1	CREG
Cadmium	0.63 - 10.5	18/34	10	EMEGchild
Lead	7.5 - 1,020	36/36	400	EPA SSL
OU3, Area B, Site 6 (disposal pits and trenches)
Aroclor-1260	0.013 - 1	6/29	0.4	CREG
Benzo(a)anthracene	0.042 - 13	5/29	7.8	RBC
Benzo(a)pyrene	0.045 - 11	5/29	0.1	CREG
Benzo(b)fluoranthene	0.054 - 13	6/29	7.8	RBC
Dibenzo(a,h)anthracene	0.044 - 1.2	3/29	0.78	RBC
Arsenic	4.6 - 15.1	29/29	0.5	CREG
Chromium	13.2 - 2,760	29/29	2,000	RMEGadult
Lead	8.3 - 634	20/20	400	EPA SSL
Mercury	0.05 - 25.6	11/29	23	EPA SSL
OU3, Area B, Site 8 (fire-fighting training area)
Benzo(a)pyrene	0.079 - 0.93	10/18	0.1	CREG
Arsenic	2 - 33.4	38/38	0.5	CREG
Lead	9.4 - 999	41/41	400	EPA SSL
Dioxins3	0.06	13/13	0.05	ATSDR guidance

Sources: Brown & Root 1996b; Department of the Navy 1999, 2000a-e; Halliburton NUS 1995; Tetra Tech NUS, Inc. 1999a, 2000b, 2000c.

Notes:

¹A single value is presented when the contaminant was detected in only one sample.
²Frequency of detection is the times sought/times detected.
³The concentration reported for dioxins is the toxicity equivalent (TEQ) calculated using ATSDR's Dioxin and Dioxin-Like Compounds in Soil Interim Policy Guidance. Under this guidance, concentrations for multiple dioxin congeners are summed and expressed as a TEQ for the most toxic form of dioxin. To calculate a TEQ for dioxin congeners at NAWC, ATSDR used the maximum detected concentrations for each congener.

Table 8: Summary of Surface Water Data That Exceed Comparison Values

Chemical	Range of Detected Concentrations (ppb)1	Frequency of Detection2	Comparison Value3 (ppb)	Source
OU1, Area A
Chloromethane	4	1/13	1.5	RBC
PCE	1	1/13	0.7	CREG
Benzo(a)anthracene	0.1	1/8	0.092	RBC
Benzo(b)fluoranthene	0.2	1/8	0.092	RBC
Cadmium	2.5	1/16	2	EMEGchild
Lead	2.9 - 28.5	5/15	15	MCL action level
Manganese	15.1 - 486	15/16	50	RMEGchild
Thallium	2	1/15	0.4	LTHA
OU1, Area B
Thallium	4.9	1/4	0.4	LTHA
OU3, Area C
Lead	1.1 -22.7	5/7	15	MCL action level
Manganese	156	1/1	50	RMEGchild

Sources: Brown & Root 1996b.

Notes:

¹A single value is presented when the contaminant was detected in only one sample.
²Frequency of detection is the times sought/times detected
³Comparison values for drinking water are presented because media-specific comparison values for surface water are not available. Drinking water comparison values may be considered overly conservative for use with surface water because these values are derived assuming daily ingestion. Surface water is present only part of the year, making daily ingestion impossible. In addition, surface water from NAWC is not used as a drinking water supply.

Table 9: Summary of Sediment Data That Exceed Comparison Values

Chemical	Range of Detected Concentrations (ppm)1	Frequency of Detection2	Comparison Value3 (ppm)	Source
OU1, Area A
Benzo(a)anthracene	0.39 - 20	19/19	0.87	RBC
Benzo(a)pyrene	0.36 - 17	19/19	0.1	CREG
Benzo(b)fluoranthene	0.54 - 25	19/19	0.87	RBC
Benzo(g,h,i)perylene	0.29 - 13	19/19	5	PADEP standard
Benzo(k)fluoranthene	0.21 - 20	19/19	8.7	RBC
Dibenzo(a,h)anthracene	0.13 - 5.3	10/19	0.087	RBC
Indeno(1,2,3-c,d)pyrene	0.24 - 14	19/19	0.87	RBC
Aldrin	0.0021 - 0.0785	5/21	0.04	CREG
Aroclor-1248	1.5	1/21	0.4	CREG
Aroclor-1260	0.16 - 1.5	3/21	0.4	CREG
Arsenic	2 - 14.05	25/25	0.5	CREG
Chromium	13.7 - 224	27/27	200	RMEGchild
Iron	10,800 - 115,500	27/27	23,000	RBC
Lead	23.9 - 404	27/27	400	EPA SSL
Manganese	115 - 11,400	27/27	7,000	RMEGchild
OU1, Area B
Benzo(a)anthracene	0.53 - 5.2	2/2	0.87	RBC
Benzo(a)pyrene	0.45 - 4.4	2/2	0.1	CREG
Benzo(b)fluoranthene	0.69 - 7.1	2/2	0.87	RBC
Benzo(g,h,i)perylene	0.36 - 2	2/2	5	PADEP standard
Indeno(1,2,3-c,d)pyrene	0.32 - 2.4	2/2	0.87	RBC
Aroclor-1260	0.27 - 1.9	4/5	0.4	CREG
OU3, Area C
Benzo(a)pyrene	0.27 - 0.66	5/9	0.1	CREG
Benzo(b)fluoranthene	0.3 - 0.9	3/7	0.87	RBC
Dibenzo(a,h)anthracene	0.08 - 0.14	3/9	0.087	RBC
Arsenic	12 - 8.5	11/11	0.5	CREG
Iron	16,200 - 25,400	3/3	23,000	RBC

Sources: Brown & Root 1996b, Tetra Tech NUS, Inc. 2000b.

Notes:

¹A single value is presented when the contaminant was detected in only one sample.
²Frequency of detection is the times sought/times detected
³Comparison values for surface soil are presented because media-specific comparison values for sediment are not available. Soil comparison values may be considered overly conservative for use with sediment because these values are derived assuming daily contact. A resident is unlikely to use the stream for recreation every day.

FIGURES

Figure 1. Vicinity Map

Figure 2. NAWC, Area Designations, and Surrounding Neighborhoods

Figure 3. Demographic Statistics (1990)

Figure 3. Demographic Statistics (2000)

Figure 4. ATSDR's Exposure Evaluation Process

Figure 5. Fracture Trace Location Map

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