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
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 other explosives to current activities in the manufacture and testing of propellants and propulsion systems for missiles and other weapons. Located approximately 35 miles south of Washington, D.C., in Charles County, Maryland, the base is comprised of the Naval Surface Warfare Center, which occupies the Cornwallis Neck peninsula, and two tenant organizations that 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 National Priorities List (NPL) hazardous waste site. Wastes generated from base operations have included waste propellants, explosives, acids, paints, solvents, and metals: the NPL listing was driven by mercury contamination of surface waters on the base. Forty-eight (48) areas have been identified for characterization and potential clean-up under the Department of Defense Installation Restoration Program (IRP). Although several clean-up actions have been completed, the majority of the sites are currently entering the Remedial Investigation phase of the process in which more in-depth sampling and evaluation are conducted.
ATSDR evaluated the environmental information for NSWC-IHDIV and identified three situations where people are currently exposed to contaminants, have been potentially exposed to contaminants in the past, or may be exposed in the future. We determined that a fourth situation does not pose a concern for public health. Summaries and ATSDR's public health evaluation of these situations are provided below.
Public Health Hazard
Exposure to
Residential Lead Sources: ATSDR has concluded that residential sources of lead
at NSWC-IHDIV currently pose a public health threat because exposures to lead are taking
place at concentrations that
may cause adverse health effects in children and women of child-bearing age. The sources of lead
include exterior and interior paints, foundation soils, and
household dusts, at the on-base and off-base residential units. Calculations using lead data
from foundation soils demonstrate the potential for blood lead levels of resident children to
increase 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 screening
program at the base to ensure coordination of educational efforts, blood lead testing, reporting
and tracking, and an action plan in the event that blood lead levels > 10 µg/dL are
identified.
Potential (Indeterminate) Public Health Hazards
Two situations were identified in which exposures to contaminant levels of health concern
could occur in the future or may have occurred in the past.
Mercury in Buildings 101 and 102: Spills of mercury impacted laboratory and general use areas of Buildings 101 and 102, potentially placing civilian employees in these buildings at risk of mercury exposure. Using historical mercury vapor data and limited medical monitoring data, ATSDR has tentatively concluded that past mercury exposures may have occurred in Buildings 101 and 102 at levels of health concern. However, potential past exposure of civilians working in these buildings between 1981 and 1991 does not place these individuals at an increased risk for reproductive problems, nor is it likely to shorten their expected life spans. Any neurological effects associated with chronic low-level exposure to the mercury vapor would have ended after the exposure stopped and would not be evident today. However, because no environmental or medical monitoring records are available for review, ATSDR cannot eliminate the possibility that the pre-1981 employees of these buildings were exposed at higher levels. ATSDR has requested the retrieval of additional medical monitoring files for employees who worked in these buildings through 1991 for our evaluation.
Fish in Mattawoman and Chicamuxen Creeks: Concentrations of cadmium, mercury, and zinc in Mattawoman Creek fish tissue are below levels of health concern and do not pose a threat to public health through ingestion. However, ATSDR recommends that sampling and analysis for lead, silver, chromium, and copper be performed to determine if these metals are entering the food chain in Mattawoman and Chicamuxen Creeks and bioaccumulating to concentrations that 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 ensure protection of the 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 in conjunction with the Maryland Department of the Environment, will ensure that the network of groundwater wells at the base does not serve as a future conduit for the migration of the shallow contaminated groundwater at the base to the deeper aquifer.
The NSWC-IHDIV is located approximately 35 miles south of Washington, D.C., in Charles County, Maryland. The Navy has conducted munitions-related activities on the property continuously since 1890. These activities have evolved from the historical testing of guns, gunpowder, and other explosives to current activities in the manufacture and testing of propellants and propulsion systems for missiles and other weapons (1).
The base occupies approximately 3,500 acres on two discrete land areas in the Potomac River drainage basin (Figure 1). The Naval Surface Warfare Center (NSWC) is located on approximately 2,500 acres on the Cornwallis Neck peninsula (2). The base is bordered on the north and east by the Potomac River, and on the south and west by Mattawoman Creek. The town of Indian Head lies immediately outside the base entrance 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 of the Naval Explosive Ordnance Disposal Technology Division at Stump Neck is to develop procedures for rendering safe weapons, missiles, and munitions. The Naval School, Explosive Ordnance Disposal, provides training in methods and procedures for recovery, evaluation, rendering safe, and disposal, of explosive ordnance (surface, underwater, conventional and nuclear types) (3). The Stump Neck Annex is bordered on the north and east by Mattawoman Creek. Chicamuxen Creek and a sparsely populated area of Charles County lay to the south and west. Information on the demographic make-up of the base and surrounding community is provided in Appendix A.
Spills, disposal, and routine releases of chemical contaminants have occurred on both parts of the base (3,4,5) resulting in the U.S. EPA 1995 listing the Naval Surface Warfare Center-Indian Head Division as a National Priorities List (NPL) site for clean-up. Wastes from base operations have included waste propellants, explosives, acids, paints, solvents, and metals (6): the NPL listing was driven by mercury contamination of surface waters (creeks, drainage ditches) at the base(6). Forty-eight (48) areas at the NSWC have been identified for characterization and potential clean-up under the Department of Defense Installation Restoration Program (IRP). Although several clean-up actions have been completed, the majority of the sites are currently entering the Remedial Investigation phase of the process in which more in-depth sampling and evaluation are conducted. A summary of ATSDR's evaluation of these sites is provided in Appendix B.
To date, characterization and environmental clean-up activities at the Stump Neck Annex have progressed under the authorities of the EPA's Resource Conservation and Recovery Act (RCRA) Corrective Action program (3). However, U.S. EPA has recently determined that the Stump Neck Annex is included in the NPL listing for the NSWC-IHDIV (Appendix B). This interpretation does not affect the scope of ATSDR's public health assessment activities: since chemical contaminants from both NSWC and the Stump Neck Annex have impacted local creeks, ATSDR evaluated the potential health effects associated with environmental conditions at both locations in support of public health assessment goals.
ATSDR Involvement: ATSDR visited the NSWC-IHDIV base on November 18-21, 1996. The purpose of the visit was to collect the information necessary to identify any public health issues related to potential exposure to environmental contamination at the facility, to identify community health concerns, and to rank the NSWC-IHDIV among other Department of Defense (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 with Navy personnel and representatives from the federal and state agencies with knowledge of the base. Our discussions addressed the nature and extent of chemical contamination at the NSWC-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. This information 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 Health Assessment document.
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