PUBLIC HEALTH ASSESSMENT

NAVAL SURFACE WARFARE CENTER
INDIAN HEAD DIVISION (NSWC-IHDIV)
(a/k/a INDIAN HEAD NAVAL SURFACE WARFARE CENTER)
INDIAN HEAD, CHARLES COUNTY, MARYLAND

SUMMARY

The Navy has conducted munitions-related activities at the Naval Surface Warfare Center-Indian Head Division (NSWC-IHDIV) continuously since the base was established in 1890. These activities have evolved from the historical testing of guns, gunpowder, and otherexplosives to current activities in the manufacture and testing of propellants and propulsionsystems for missiles and other weapons. Located approximately 35 miles south ofWashington, D.C., in Charles County, Maryland, the base is comprised of the Naval SurfaceWarfare Center, which occupies the Cornwallis Neck peninsula, and two tenant organizationsthat occupy the Stump Neck Annex on the nearby Stump Neck peninsula.

The NSWC-IHDIV was designated in 1995 by the U.S. EPA as a NationalPriorities List (NPL) hazardous waste site. Wastes generated from base operations have included wastepropellants, explosives, acids, paints, solvents, and metals: the NPL listing was driven bymercury contamination of surface waters on the base. Forty-eight (48) areas havebeenidentified for characterization and potential clean-up under the Department of DefenseInstallation Restoration Program (IRP). Although several clean-up actions have beencompleted, the majority of the sites are currently entering the Remedial Investigation phaseof the process in which more in-depth sampling and evaluation are conducted.

ATSDR evaluated the environmental information for NSWC-IHDIV and identified threesituations where people are currently exposed to contaminants, havebeen potentiallyexposedto contaminants in the past, or may be exposed in the future. We determined that a fourthsituation does not pose a concern for public health. Summaries and ATSDR's public healthevaluation of these situations are provided below.

Public Health Hazard
Exposure toResidential Lead Sources: ATSDR has concluded that residential sources of leadat NSWC-IHDIV currently pose a public health threat because exposures to lead are takingplace at concentrations thatmay cause adverse health effects in children and women of child-bearing age. The sources of leadinclude exterior and interior paints, foundation soils, andhousehold dusts, at the on-base and off-base residential units. Calculations using lead datafrom foundation soils demonstrate the potential for blood lead levels of resident children toincrease above the CDC public health standard of 10 micrograms per deciliter (µg/dL). ATSDR has recommended that actions be taken to improve the voluntary lead screeningprogram at the base to ensure coordination of educational efforts, blood lead testing, reportingand tracking, and an action plan in the event that blood lead levels > 10 µg/dL areidentified.

Potential (Indeterminate) Public Health Hazards
Two situations were identified in which exposures to contaminant levels of health concerncould occur in the future or may have occurred in the past.

Mercury in Buildings 101 and 102: Spills of mercury impacted laboratory andgeneral useareas of Buildings 101 and 102, potentially placing civilian employees in these buildings at riskof mercury exposure. Using historical mercury vapor data and limited medicalmonitoring data,ATSDR has tentatively concluded that past mercury exposures may have occurred in Buildings101 and 102 at levels of health concern. However, potential past exposure of civilians workingin these buildings between 1981 and 1991 does not place these individuals at an increasedrisk for reproductive problems, nor is it likely to shorten their expected life spans. Anyneurological effects associated with chronic low-level exposureto the mercury vapor wouldhave ended after the exposure stopped and would not be evident today. However, becauseno environmental or medical monitoring records are available for review, ATSDR cannoteliminate the possibility that the pre-1981 employees of these buildings were exposed athigher levels. ATSDR has requested the retrieval of additional medical monitoring files foremployees who worked in these buildings through 1991 for our evaluation.

Fish in Mattawoman and Chicamuxen Creeks: Concentrations of cadmium,mercury, and zincin Mattawoman Creek fish tissue are below levels of health concern and do not pose a threatto public health through ingestion. However,ATSDR recommends that sampling and analysisfor lead, silver, chromium, and copper be performed to determine if these metals are enteringthe food chain in Mattawoman and Chicamuxen Creeks and bioaccumulating to concentrationsthat require consumption limits to protect the health of people eating the fish.

No Public Health Hazard

Drinking Water Supply: Actions have been taken by the NSWC-IHDIV to ensureprotection ofthe deep groundwater resources that serve as the water supply for the base and the region. The NSWC-IHDIV wellhead protection program, currently being developed by the base inconjunction with the Maryland Department of the Environment, will ensure that the network ofgroundwater wells at the base does not serve as a future conduit for the migration of theshallow contaminated groundwater at the base to the deeper aquifer.

BACKGROUND

The NSWC-IHDIV is located approximately 35 miles south of Washington, D.C., in CharlesCounty, Maryland. The Navy has conducted munitions-related activities on the propertycontinuously since 1890. These activities have evolved from the historical testing of guns,gunpowder, and other explosives to current activities in the manufacture and testing ofpropellants and propulsion systems for missiles and other weapons ⁽¹⁾.

The base occupies approximately 3,500 acres on two discrete land areas in the Potomac Riverdrainage basin (Figure 1). The Naval Surface Warfare Center (NSWC) is located onapproximately 2,500 acres on the Cornwallis Neck peninsula ⁽²⁾. Thebase is bordered on thenorth and east by the Potomac River, and on the south and west by Mattawoman Creek. Thetown of Indian Head lies immediately outside the baseentrance to the northwest.

The remaining acreage is located at the Stump Neck Annex on the Stump Neck peninsula. The Annex lies south of the NSWC and is occupied by tenant organizations⁽²⁾. The mission ofthe Naval Explosive Ordnance Disposal Technology Division at Stump Neck is to developprocedures for rendering safe weapons, missiles, and munitions. The Naval School, ExplosiveOrdnance Disposal, provides training in methods and procedures for recovery, evaluation,rendering safe, and disposal, of explosive ordnance (surface, underwater, conventional andnuclear types) ⁽³⁾. The Stump Neck Annex is bordered on the northand east by MattawomanCreek. Chicamuxen Creek and a sparsely populated area of Charles County lay to the southand west. Information on the demographic make-up of the base and surrounding community isprovided in Appendix A.

Spills, disposal, and routine releases of chemical contaminants have occurred on both parts ofthe base ^(3,4,5) resulting in the U.S. EPA 1995 listing the Naval SurfaceWarfare Center-IndianHead Division as a National Priorities List (NPL) site for clean-up. Wastes from baseoperations have included waste propellants, explosives, acids, paints, solvents, and metals⁽⁶⁾:the NPL listing was driven by mercury contamination of surface waters (creeks, drainageditches) at the base^(6). Forty-eight (48) areas at the NSWC have beenidentified forcharacterization and potential clean-up under the Department of Defense InstallationRestoration Program (IRP). Although several clean-up actions have been completed, themajority of the sites are currently entering the Remedial Investigation phase of the process inwhich more in-depth sampling and evaluation are conducted. A summary of ATSDR'sevaluation of these sites is provided in Appendix B.

To date, characterization and environmental clean-up activities at the Stump Neck Annexhaveprogressed under the authorities of the EPA's Resource Conservation and Recovery Act(RCRA) Corrective Action program ⁽³⁾. However, U.S. EPA hasrecently determined that theStump Neck Annex is included in the NPL listing for the NSWC-IHDIV (Appendix B). Thisinterpretation does not affect the scope of ATSDR's public health assessment activities: sincechemical contaminants from both NSWC and the Stump Neck Annex have impacted localcreeks, ATSDR evaluated the potential health effects associated with environmental conditions at both locations in support of public health assessment goals.

Figure 1. Site Location Map

ATSDR Involvement: ATSDR visited the NSWC-IHDIV base on November18-21, 1996. Thepurpose of the visit was to collect the information necessary to identify any public health issuesrelated to potential exposure to environmental contamination at the facility, to identifycommunity health concerns, and to rank the NSWC-IHDIV among other Department ofDefense (DOD) installations according to its potential public health hazard.

During our tour of the site to observe the environmental conditions at the base, we met withNavy personnel and representatives from the federal and state agencies with knowledge of thebase. Our discussions addressed the nature and extent of chemical contamination at theNSWC-IHDIV, the proximity of chemically contaminated areas to on and off-base populations,and the types of human activities that could lead to exposures to the contamination. Thisinformation has been integrated with our review of environmental sampling data to draw the conclusions about public health issues at NSWC-IHDIV that are presented in this Public HealthAssessment document.

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