PUBLIC HEALTH ASSESSMENT
NORFOLK NAVAL BASE
(a/k/a SEWELLS POINT NAVAL COMPLEX)
NORFOLK, NORFOLK CITY COUNTY, VIRGINIA
Naval Station Norfolk (NSN) is the largest naval base in the United States. Its mission is to provide fleet support and readiness for the U.S. Atlantic Fleet. The base is comprised of the two installations previously known as Naval Air Station Norfolk and Naval Station Norfolk, both established in 1917. NSN is located on 4,631 acres on the Sewells Point peninsula in northern Norfolk, Virginia. Willoughby Bay is to the north and the Elizabeth River is to the west. Mason Creek forms a portion of NSN's eastern border. Residential, commercial, and industrial areas are to the east and south, as well as being inset into the southwestern portion of the base. This part of Norfolk, which includes the Glenwood Park community, is surrounded by the base on three sides and the Elizabeth River to the west. NSN is fenced, and public access is not allowed.
Activities conducted at NSN include defueling, refueling, painting, paint stripping, equipment cleaning, engine maintenance, sandblasting, metal plating, and loading and unloading of products used aboard vessels. In 1983, efforts began to identify site-related contamination resulting from the handling and disposal of products used at the base. Twenty-two sites were identified under the U.S. Department of Defense's Installation Restoration Program (IRP). On April 1, 1997, the U.S. Environmental Protection Agency (EPA) added the base to the National Priorities List. Since then, 20 other potentially-contaminated areas identified as solid waste management units have been designated areas of concern (AOCs) or site screening areas (SSAs). An investigation of each IRP site, AOC, and SSA has been completed or is under way. Based on the results at each site, appropriate actions that are protective of human health will be selected.
The Agency for Toxic Substances and Disease Registry (ATSDR) visited NSN in 1998 and 2000 to collect information about how people on and off site might be exposed to environmental contamination, to obtain environmental sampling data, and to learn about community health concerns. ATSDR obtained additional information from the city of Norfolk, Norfolk Department of Public Health, Virginia Department of Health, Virginia Department of Environmental Quality (VDEQ), and EPA. ATSDR prepared this public health assessment to evaluate past, current, and potential future exposures to contaminants originating at NSN. We evaluated exposures to on-site and off-site drinking water and to fish and shellfish from Willoughby Bay. We also addressed the community's concerns, including those about potential public health effects to the Glenwood Park community and to children in the vicinity of the Camp Allen Elementary School. ATSDR concluded that these potential exposures would be too low to cause any adverse health effects.
NSN has identified groundwater contamination in both the shallow and deep aquifers underlying the base. The contamination extends north and west of Area A of the Camp Allen Landfill and southeast of Area B of the landfill. A groundwater treatment system has been installed in the Camp Allen Landfill area. Low levels of volatile organic compounds (VOCs) were detected in a few isolated instances in Glenwood Park wells in 1991. The detected levels of contaminants would not be expected to result in adverse health effects and are not thought to be related to groundwater contamination originating from NSN.
The city of Norfolk provides drinking water to properties within the city, including NSN, from lakes, rivers, and wells more than 2 miles from NSN. The only identified wells located near the base that draw shallow groundwater are in the Glenwood Park community and are not used for drinking water. Because no one drinks water from the shallow aquifer, no public health hazard exists. There are no wells drawing drinking water from the deep aquifer downgradient of site-related contamination. Thus, deep groundwater poses no public health hazard.
In response to a request made at a NSN Restoration Advisory Board meeting in 1998, ATSDR evaluated available data relating to NSN drinking fountains and faucets. Some locations have been sampled for lead and copper, which can leach into water from water distribution pipes. Both the city and the Navy take measures to reduce the potential for exposure to metals from pipes. Most available samples contained concentrations of lead and copper that would not be expected to result in adverse health effects under infrequent exposure scenarios. The only location where ATSDR found a recent pattern of lead concentrations exceeding regulatory limits was a faucet at Building Z-103. ATSDR recommends that the Navy verify that this faucet is not routinely used for drinking water. If the Navy determines that it is, ATSDR recommends that the faucet be resampled. If contaminant levels exceed safe limits, the Navy should take appropriate measures to ensure that people are not exposed to these levels of contaminants.
ATSDR reviewed all available surface water, sediment, and fish and shellfish samples collected from Willoughby Bay, as well as available information about potential fish and shellfish consumption patterns. A limited number of fish and shellfish samples collected between 1971 and 2001 contained slightly elevated levels of some metals, but most of these metals were not present at levels that would pose a potential public health hazard. Detected levels of zinc in some samples, however, could have caused temporary and reversible acute effects (gastrointestinal distress or short-term decreases in cortisol, a hormone produced by the body in response to stress). These zinc levels will not result in any long-term adverse health effects. Because the small number of samples analyzed precluded a definitive evaluation, ATSDR recommended in spring 2001 that VDEQ collect a variety of seafood species from Willoughby Bay and analyze them for arsenic and zinc, among other metals. VDEQ adopted these recommendations. ATSDR reviewed the sampling results in summer 2002 and determined that the contaminant levels in these samples (including zinc levels) would not result in any long-term adverse health effects.
As a part of our exposure evaluation and in response to community concerns, ATSDR evaluated potential exposures to children in the vicinity of the Camp Allen Elementary School. Elevated concentrations of a few contaminants have been detected near the school (southeast of NSN's Camp Allen Landfill) in groundwater, soil, and drainage ditch surface water and sediment. Because the detected concentrations are relatively low and exposures are expected to be limited and incidental, contact with contaminants would not be expected to result in adverse effects to children. Indoor air samples collected in 1992 from the school and the nearby base brig did not contain levels of contaminants that would result in adverse health effects. If future groundwater monitoring indicates that substantial groundwater contamination is migrating beneath the school or other areas where people live or work, ATSDR recommends the Navy evaluate the appropriateness of collecting additional indoor air samples.
The largest naval installation in the country, Naval Station Norfolk (NSN) provides facilities and support for Navy vessels, aircraft, and other activities of the United States Atlantic Fleet. NSN is located on 4,631 acres. It is in the northern portion of Norfolk, about 90 miles southeast of Richmond, Virginia, and 185 miles south of Washington, D.C. (see Figure 1). The base is sited on a peninsula known as Sewells Point. Willoughby Bay is to the north. The Elizabeth River is to the west, and the tidal basin at the confluence of the Elizabeth and James Rivers, known as Hampton Roads, is to the northwest. Mason Creek forms a portion of NSN's eastern boundary. Norfolk lies east and south of the base. A part of Norfolk also is inset into the southwestern portion of the base, along the Elizabeth River. This area, which includes the Glenwood Park community, is surrounded by the base on three sides. The surrounding land use is primarily industrial, mixed with commercial and residential areas. Shipping facilities are located in the waterfront area south of the base, and there are some residential areas to the south and east (CH2MHILL 1997a, 1999; FFA 1999).
Effective February 1999, the installations then known as Naval Station Norfolk and Naval Air Station Norfolk were merged into a single installation called Naval Station Norfolk. The naval base was originally established on 474 acres known as Sewells Point Naval Complex in June 1917, to support the war effort. Naval facilities were commissioned as the Hampton Roads Naval Operating Base in October 1917. The Naval Air Station (originally named Naval Air Detachment, Curtiss Field, Newport News) started training aviators in May 1917. Five months later, it was moved across the James River adjacent to Hampton Roads Naval Operating Base. Planes were stationed in Norfolk to patrol the Atlantic Coast, and the site also housed a training center. Significant expansion occurred during and after World War II by dredging and filling operations and land acquisition (EDAW 1995; Naval Station Norfolk n.d.a.).
The mission of the base is to provide fleet support and readiness for the Atlantic Fleet. Approximately 105 ships are stationed at the base. There are approximately 260 tenants supporting Navy activities on site (Naval Station Norfolk n.d.a.; ATSDR-DHAC 1998a). Maintenance and repair work conducted at NSN include defueling, refueling, utilities hook-up, painting, paint stripping, patching, cleaning, engine maintenance, sandblasting, and metal plating. Fuels, oils, and other products used aboard vessels are also loaded and unloaded at the base (ATSDR-DHAC 1998a). The majority of contamination identified at the base has resulted from the handling and disposal of products used at the facility over time, including solvents, corrosives, paints, electroplating wastes, petroleum products, oils, and lubricants (EPA 1999).
In February 1983, an initial assessment study of the base was completed. Available records, site reconnaissance, and interviews with employees resulted in the identification of 18 possible areas (termed Sites 1 through 18) where contaminants might have affected the environment and the recommendation that six of the areas be investigated further. Subsequent confirmation studies evaluated the extent of contamination at and the possibility of chemical migration from the six sites of concern (Sites 1 through 6). The other sites were recommended for no further action, although cleanup activities were conducted at some of them (Sites 11, 14, 15, 16, and 17) (Baker 1993; CH2MHILL 1999a). (See Appendix A, which summarizes available information about sites that have been or will be investigated.)
In April 1986, a fire started at building V-60 and spread to building V-90. Transformers containing polychlorinated biphenyls (PCBs) ruptured from the heat, resulting in the spread of PCB contamination. This area was designated Site 19, and cleanup of the site was completed in 1991. By May 1993, three other areas had been added to the list of sites to be investigated under the Department of Defense's Installation Restoration Program (IRP) and designated Sites 20 through 22. (See Figure 2, which depicts the IRP sites.)
In 1996, the Navy and U.S. Environmental Protection Agency (EPA) identified 148 potentially contaminated sites on the basis of an EPA Resource Conservation and Recovery Act (RCRA) facility assessment, aerial photography provided by EPA's Environmental Photographic Interpretation Center, and field inspections. Sampling has been performed at selected sites and reported in two relative risk ranking data collection sampling and analysis reports released in 1996. On the basis of these sampling results, 25 solid waste management units (SWMUs) were initially recommended for additional evaluation. Another 8 SWMUs were added in 1997 and 1998. A removal action was conducted at SMWU 1 as part of the sediment removal at the CD Landfill in 1997, and the SMWU was recommended for no further action. SMWU 37 and other potentially contaminated sites that contain underground and aboveground storage tanks are being addressed in accordance with applicable Commonwealth of Virginia regulations. The base stormwater drainage system, designated SWMU 36, is undergoing an assessment and rehabilitation project, and no further investigation of the site as a SWMU is planned.
On April 1, 1997, pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), EPA added the base to the National Priorities List (NPL). That summer, a groundwater extraction and treatment system and a soil vapor extraction system began operating at the Camp Allen Landfill (Site 1). Drums containing waste solvents and contaminated soil have been excavated from the landfill area and disposed of off site. In 1998, groundwater treatment systems and soil vapor extraction systems began operating at Site 3 (Q-Area Drum Storage) and Site 20 (Building LP-20), contaminated soil was removed from Site 22 (Camp Allen Salvage Yard), and a record of decision (ROD) was signed for Site 6 (CD Landfill). The ROD for the CD Landfill requires it to be capped, groundwater to be monitored, and nearby contaminated sediment to be excavated. In 1999, the CD Landfill cap was installed. Soil was also removed from Site 5 (Pesticide Disposal Site) in 1999, and a sediment removal and soil paving/cover was conducted at Site 2 (NM Slag Pile). In 2000, work on a facility-wide background study and an ecological study of Bousch Creek began (LANTDIV 2000; CH2MHILL 2000d).
The Navy entered into a Federal Facilities Agreement (FFA) with EPA, effective February 1999, governing investigation and remediation activities at NSN. EPA and the Navy agreed that no further action was necessary at Sites 7 through 18, and 10 SWMUs were recommended for no further action. The FFA also grouped five SWMUs into four site screening areas (SSAs) and 15 SWMUs into eight areas of concern (AOCs) (FFA 1999). Table 1 lists the SSAs and AOCs and the SWMUs each comprises, and Figure 3 depicts the SWMUs. SSAs are subject to the site screening process to determine whether contamination has been released to the environment from them. Site investigations were completed for each SSA in 1998 or 1999, and further plans for each SSA will be determined after the results of a facility-wide background study become available. AOCs undergo review to determine whether they should be converted to SSAs or they require no further action. In May 2000, the Navy determined that no further action was required at the sites that had been designated AOCs 1, 3, 7, and 8. The Navy plans to further investigate AOCs 2, 4, 5, and 6 (CH2MHILL 2000d).
In July 1998, the Agency for Toxic Substances and Disease Registry (ATSDR) conducted an initial site visit and met with representatives of Naval Station Norfolk, the Atlantic Division of the Naval Facilities Engineering Command, and the Naval Environmental Health Center, as well as representatives of other interested governmental agencies. ATSDR also attended a Restoration Advisory Board (RAB) meeting to solicit community concerns about the base (ATSDR-DHAC 1998a). On October 29, 1998, ATSDR released a health consultation containing a summary of potential public health issues at Naval Station Norfolk.
During the July 1998 site visit, ATSDR observed that the fence around the Camp Allen Salvage Yard (Site 22) was not intact. Since the salvage yard is not within the fenced part of NSN and is not far from the Camp Allen Elementary School, ATSDR recommended that it be repaired to prevent access by trespassers. Removal of contaminated surface soil at the site began 2 weeks after ATSDR's visit, and the fence was repaired in October 1998 (ATSDR-DHAC 1998b; Heaney 1999). The Navy is committed to keeping the fence intact (Naval Station Norfolk 2000).
In May 2000, ATSDR conducted another site visit to gain an understanding of current site conditions and of the status of remedial actions, as well as to collect site-related documents and environmental data.
As a part of other work in the Hampton Roads area, ATSDR will be reviewing studies by other agencies on the capture, consumption patterns, and potential exposure of recreational and subsistence fishers, and consumers of local seafood to contaminants present in area waters. Potential sources of contamination to seafood include various federal government and private industrial NPL sites, as well as associated regional and local point and non-point sources from surrounding residential, urban, and industrial areas. It is not a goal of this review to identify where and how seafood species come into contact with environmental contaminants. The goal is to understand how to provide adequate guidance to prevent exposures to concentrations of chemicals in the local seafood that could cause adverse health effects.
Additionally, ATSDR realizes that a number of stakeholders (local private citizens; environmental groups; community groups; local, state, and federal agencies; academia; and industries) have actively been looking at seafood issues in the Elizabeth River watershed for decades. As a part of this regional study, ATSDR will be consulting with stakeholders to identify and discuss issues, as well as to share and evaluate additional information, relating to possible seafood contamination in the region.
At the time of the 1990 U.S. Census, the total population within 1 mile of the site was 74,409. Of these people, about 71% were white, about 23% were black, and the remaining individuals were of other racial origins. The population included 6,978 children under the age of six; 5,049 adults over the age of 65; and 13,628 females of reproductive age (15 - 44 years).
In 1997, there were 58,175 military employees and 12,657 civilian employees associated with the base (Naval Base, Norfolk n.d.). NSN supports the largest military population of any base in the world (Naval Station Norfolk n.d.a.). Most military employees spend only 2 to 4 years stationed at the base (Naval Station Norfolk 2000). There are approximately 20 piers, 4,000 buildings, and an airfield on site (CH2MHILL 1999a).
The nearest residences to the base are in the Glenwood Park community, a residential neighborhood of 3,600 people (ATSDR-DHAC 1998a). There are houses in Glenwood Park as close as 200 feet west of the Camp Allen Landfill (Site 1), although a dense woods divides the home from the landfill. Also near the Camp Allen Landfill and Camp Allen Salvage Yard are the Capehart Navy Military Housing Area, the Camp Allen Elementary School (which opened in 1970), and the Camp Elmore U.S. Marine Corps barracks (Baker 1993). While there are several Navy family housing areas near the base, there are only 109 on-base housing units. As of December 2000, there were 92 military personnel and 229 dependents living in on-base housing (Bridges 2000).
Camp Allen Elementary School is the only school within NSN. It is less than 1,000 feet southeast of Site 22, the Camp Allen Salvage Yard (Baker 1993). Other schools within 1 mile of the site include Willoughby Elementary School to the northeast, Northside Middle School to the east, Granby High School to the south, and Sewells Point Elementary School near the southwestern corner of the base.
Access to NSN is restricted to military personnel, civilian employees, and authorized visitors. The base is surrounded by a perimeter fence. People entering the facility must pass through guarded entrance gates. Within base boundaries, the following contaminated sites are fenced: Sites 3, 5, 6, 21, and 22. Also, within the Camp Allen Landfill area, Area B is fenced, but Area A is not (Naval Station Norfolk 2000; Baker 1993).
NSN elevation ranges from sea level at the northern and western edges to about 15 feet above sea level in the center of the site. Most surface water drains to Mason Creek to the east or to the area formerly occupied by Bousch Creek. The main channel of Bousch Creek was filled and replaced by a network of drainage ditches, channels, and culverts during the development of the installation. Mason Creek and the remnant tributaries to Bousch Creek are tidal and drain to Willoughby Bay, which discharges to the Chesapeake Bay. Some surface water runoff from the base flows to the Elizabeth River (CH2MHILL 1997a). As previously noted, the NSN stormwater drainage system is undergoing comprehensive inspection and rehabilitation. The base has also implemented a program to monitor its discharges to the Hampton Roads Sanitation District (FFA 1999). No drinking water intakes are downstream of the site.
The Elizabeth River hosts a great deal of shipping traffic with extensive industrial activity along its banks. Norfolk Naval Shipyard, the largest naval shipyard in the world, also an NPL site, is located adjacent to the river. Contamination from point sources and runoff resulted in the river being designated a Region of Concern by EPA's Chesapeake Bay Program in 1993. Various cooperative committees studying the river advise against swimming in the river near its shores. However, the river is used for other types of recreation, including boating and fishing in some areas (Alliance for the Chesapeake Bay n.d.; EPA Chesapeake Bay Program 1999; Elizabeth River Project 1996).
Boating, fishing, and crabbing are popular in Willoughby Bay. There are several marinas and numerous piers from which fishing is allowed along the bay. There are several public and community beaches west of the base along the Chesapeake Bay, separated from the Willoughby Bay by Willoughby Spit (LeBleu 1996). There are no designated swimming areas on the Willoughby Bay or the Elizabeth River in the immediate vicinity of NSN (Baker 1993).
In preparing this public health assessment, ATSDR reviewed and evaluated information provided in the referenced documents. Documents prepared for the IRP program must meet specific standards for adequate quality assurance and control measures for chain-of-custody procedures, laboratory procedures, and data reporting. The environmental data presented in this public health assessment are from Navy sampling reports, including investigations of the IRP sites, AOCs, and SSAs, as well as sampling of water from drinking fountains and faucets; Virginia Department of Health (VDOH) and Virginia Department of Environmental Quality (VDEQ) databases; EPA reports and databases; and city of Norfolk water quality sampling reports. The limitations of these data have been identified in the associated reports.After evaluating the data, ATSDR determined that the quality of environmental data available in most site-related documents for NSN is adequate to make public health decisions. Data validation was not available for the majority of samples collected from Willoughby Bay, except 1995 samples collected by EPA's Chesapeake Bay Program and 1998 samples collected by VDEQ.
In this section, ATSDR evaluates whether community members have been (past), are (current), or could be (future) exposed to harmful levels of contaminants in the environment. Figure 4 describes the conservative exposure evaluation process used by ATSDR. As the figure indicates, ATSDR considers how people might come into contact with, or be exposed to, contaminated media. Specifically, ATSDR determines whether an exposure could occur through ingestion, dermal (skin) contact with contaminated media (e.g., soil or groundwater), or inhalation of vapors. ATSDR also considers the likely length (duration) and frequency of the exposure.
If exposure was or is possible, ATSDR then considers whether contaminants were or are present at levels that might be harmful to people. ATSDR does this by screening the concentrations of contaminants in an environmental medium (e.g., soil or groundwater) against health-based comparison values (CVs). CVs are contaminant concentrations that health scientists have determined are not likely to cause adverse effects, even when assuming very conservative exposure scenarios. Because CVs are not thresholds of toxicity, environmental levels that exceed comparison values would not necessarily produce adverse health effects. If a contaminant is found in the environment at levels exceeding its corresponding CVs, ATSDR examines potential exposure variables and the toxicology of the contaminant. ATSDR emphasizes that regardless of the level of contamination, a public health hazard exists only if people come in contact with, or are otherwise exposed to, harmful levels of contaminants in site media.
After an initial review of potential health hazards at NSN, ATSDR identified the drinking water and biota exposure pathways as requiring further evaluation. Following the strategy outlined above, ATSDR examined whether human exposure to harmful levels of contaminants via these pathways existed in the past, exists now, or could potentially exist in the future. ATSDR summarizes its evaluation of potential exposure pathways in Table 2 and describes it in more detail in the discussion that follows. To acquaint readers with terminology used in this report, a glossary is included as Appendix B. In addition, Appendix C presents the methods and assumptions used to estimate exposures and support some of the report's conclusions.
Has contaminated groundwater from Naval Station Norfolk moved off site, and does it impact any municipal or private wells in the vicinity? If so, is there a potential for it to result in adverse health effects?
ATSDR reviewed area hydrogeologic information, available information about wells in the vicinity of NSN, and information about the nature and extent of groundwater contamination to assess the potential for adverse health effects to occur as a result of exposure to off-base drinking water. The city of Norfolk provides drinking water to Norfolk residents and businesses, including NSN, and requires that city water be used where it is available.
Water in the shallow Columbia Aquifer is not considered potable in the vicinity of NSN because it contains high concentrations of iron and manganese and has a low pH. In fact, the city of Norfolk prohibits using wells that draw shallow groundwater to provide drinking water. The only wells that ATSDR identified near the base that draw from this aquifer are in Glenwood Park and are used only for outdoor purposes, such as watering of gardens, not for drinking water. In addition, available information indicates that these wells are not expected to be affected by contamination originating from NSN. The low levels of a few contaminants detected in several wells would be unlikely to result in adverse health effects. Thus, exposure to shallow groundwater poses no public health hazard.
Contamination in the deep Yorktown Aquifer would not be expected to cause adverse health effects because there are no drinking water wells drawing water from this aquifer downgradient of site-related groundwater contamination. Therefore, deep groundwater poses no public health hazard.
The geologic formation that immediately underlies NSN is approximately 60 feet deep and is known as the Columbia Group. The upper 20 to 40 feet of the formation, consisting of unconsolidated silt and fine sand, holds groundwater and is known as the shallow (or Columbia) aquifer. Hydraulic conductivity in the shallow aquifer is relatively low because groundwater does not flow easily through the silt and fine sand. The depth to the water table is usually less than 8 feet. This aquifer discharges to Mason Creek, the Elizabeth River, and the James River at Willoughby Bay (CH2MHILL 1999a; Kearney 1990).
The lower 20 to 40 feet of the Columbia Group are relatively impermeable and are made up of silt, clay, and sandy clay. Underlying the Columbia Group is the Yorktown Formation, which is approximately 90 to 100 feet thick in this area. There is a clay layer in the upper portion of this formation, and below this layer are moderately coarse sand, gravel, and shell fragments that hold groundwater. The water-bearing zone is known as the Yorktown Aquifer and is semiconfined by the overlying clay layer (CH2MHILL 1999a). Confining beds are thought to be absent in some areas, including the Camp Allen area, allowing groundwater to migrate from the shallow aquifer to the Yorktown Aquifer (Kearney 1990).
The city of Norfolk provides drinking water to Norfolk (including NSN), Chesapeake, and Virginia Beach. This water is drawn from the Blackwater River, the Nottoway River, and nine lakes, six of them at least 2.75 miles southeast of the base and the other three more than 15 miles southwest of the base. These surface water sources are sometimes supplemented by four wells drawing deep groundwater. All four wells are more than 5 miles southwest of NSN; three are located in Suffolk, and the other is in Isle of Wight County. Before being distributed, water is treated at either the Moores Bridge or 37th Street water treatment plant (Rosenthal 2001; City of Norfolk 2001). Since 1992, the city of Norfolk has required properties within the city to be connected to the public water supply if they are located on streets where public water supply lines are available. In these areas, alternative water supplies (e.g., private wells) may be used only for heating and cooling, irrigation, and other outdoor uses (Norfolk City Code 1995). Reportedly, a city of Norfolk ordinance also prohibits any use of the shallow aquifer for drinking water due to high concentrations of iron and manganese, as well as a low pH (CLEAN 1999).
In the past, there was no comprehensive requirement for individuals to register their wells with the state, county, or city when they were drilled. However, wells designed to draw more than 300,000 gallons of water per month were required to obtain groundwater withdrawal permits from the VDEQ (Newton 2001). In 1990, a requirement to register all private wells with the Department of Public Health came into effect (Graves 2001). ATSDR contacted VDEQ and the Department of Public Health to request information about recorded wells in the vicinity of the site. Neither agency had records of any residential drinking water wells within 1 mile of the site.
VDEQ records, supplemented by information collected by the Navy, indicate that there are two industrial wells located about ¼ mile southwest of the CD Landfill, east of Hampton Boulevard, which formerly served Global Technology Systems (formerly Sheller-Globe) and three additional wells used by the Lone Star cement plant in its industrial process, located about ½ mile west of the Global Technology Systems wells. VDEQ records also indicate that a well drawing from the deep aquifer was drilled at the Mercury Roller Rink (later Olympic Skateway), at the intersection of Granby Street and Interstate 564, about 1,000 feet southeast of the southeastern corner of NSN. VDEQ did not have any additional information about the use of this well. NSN reports reveal that a well at building MCA-600 drawing from the deep aquifer was used until 1991 for lawn watering. This well, located about 500 feet east of Camp Allen Landfill Area B, was sampled in the 1980s and reportedly did not contain contamination. Finally, there are some wells drawing from the shallow aquifer in the Glenwood Park community, west of Area A of the Camp Allen Landfill, but the water drawn from them is used outdoors and is not used for drinking water. None of these wells are thought to be downgradient of NSN (Baker 1994b, 1995b, 1996b; VDEQ-RS 2000, 2001; Graves 2001).
Nature and Extent of Contamination
ATSDR reviewed available NSN groundwater samples collected on the base and in nearby off-site areas in connection with investigations of IRP sites, AOCs, and SSAs, as well as information about NSN groundwater treatment systems. ATSDR focused on the nature and extent of contamination that has extended or might extend off site and to areas where people live, work or go to school. These data are described in the following two sections, which address shallow groundwater and deep groundwater separately. In some areas, the two aquifers are connected, as the confining layer between them is discontinuous. On-site sampling data are presented in Appendix A.
The only shallow (Columbia Aquifer) groundwater contamination that is known to extend off site is located in the Camp Allen area. The CD Landfill is unlikely to be the source of off-site groundwater contamination. Shallow groundwater flow near the CD Landfill is generally to the east (and slightly to the south), and the base boundary is more than 1,000 feet to the southwest (CH2MHILL 2001b).
Volatile organic compounds (VOCs) are present near the boundary of NSN in the Camp Allen Landfill Area A. Two areas of groundwater contamination within Area A have been identified and labeled Area A1 and Area A2. Area A1 includes the brig area and the southern portion of Area A, while Area A2 is in the northern part. Figure 5 depicts the Camp Allen area, including Areas A1 and A2. In general, shallow groundwater in Area A flows radially outward from the brig, in the central part of Area A. It flows towards a drainage ditch that begins at the Camp Allen Elementary School and runs just outside of the boundary of Area A, within the NSN property line. Water in this ditch flows northward along the western boundary of Area A, where it is joined in Area A2 by a smaller ditch that runs along the northern portion of the site. The ditches, located between Camp Allen Landfill Area A and the NSN property line, are tidally-influenced and thought to serve as a hydrogeologic boundary between the Camp Allen area and off-site areas to the west. Groundwater flow in the shallow aquifer is relatively low because the aquifer is thin and has a low hydraulic conductivity (Baker 1994b; CH2MHILL 2001b).
Two extraction wells drawing shallow groundwater were installed in Area A2 in the late 1990s as part of the groundwater treatment system. The wells are located south of the smaller drainage ditch. Because groundwater does not flow easily through the silt and fine sand that makes up the shallow aquifer, the extraction wells capture only contaminated groundwater in their immediate vicinity (i.e., within several feet). Few shallow groundwater samples have been analyzed from the monitoring wells north of the extraction wells. One sample collected in 2001 did not contain any VOCs, except a trace of one VOC well below its CV.
A third shallow groundwater extraction well was drilled in Area A1, just west of the brig and east of the larger drainage ditch. This extraction well is no longer in use because shallow and deep groundwater are hydraulically connected in the area (because the confining layer between them is discontinuous) and deep extraction wells can capture shallow groundwater. There are three deep groundwater extraction wells nearby, as well as a deep extraction well about 600 feet further to the south, southeast of the terminus of Glenview Avenue (CH2MHILL 2001b).
Shallow groundwater contamination from the Camp Allen Landfill would not be expected to extend beyond the drainage ditch west of Area A1 because the ditch serves as a hydrogeologic barrier preventing shallow groundwater contamination from moving off site. One off-base monitoring well west of the drainage ditch contained very low levels of several VOCs in 1991 (1 microgram per liter [µg/L] benzene, 1 µg/L tetrachloroethylene [PCE], 1 µg/L toluene, 2 µg/L xylene, 10 µg/L acetone, and 10 µg/L methylene chloride). The methylene chloride concentration exceeds the drinking water CV of 5 µg/L, but this VOC is a possible laboratory contaminant. The benzene concentration also slightly exceeded its CV of 0.6 µg/L. The same well was resampled in 1992 and 1993, and no VOCs were present at measurable concentrations. No samples have been collected from off-site wells drawing from the shallow aquifer in this area since 1993, but a few samples from the deep aquifer are available. Shallow groundwater is hydraulically connected to deep groundwater in the region. Deep groundwater is discussed further in the next section (Baker 1994b, CH2MHILL 2001b, Johnson 2001).
In Camp Allen Area B, there are thought to be several sources of groundwater contamination, in both the northern and southern parts of the site. Shallow aquifer contamination (primarily metals and VOCs that are found in solvents, fuel, and fuel oil) is migrating to the southeast. Southeast of the northern part of Area B is the Camp Elmore Marine Corps Barracks and C Street, which runs perpendicular to the boundary of Area B. South of C Street is the Camp Allen Elementary School. Since 1998, seven extraction wells have been pumping and treating contaminated groundwater southeast of Area B. The lateral extent of the capture zones is less than 800 feet in Area B. Figure 6 depicts Area B and vicinity, as well as the locations of extraction wells and shallow monitoring wells (Baker 1994b, CH2MHILL 2001b).
Table 3 presents the highest levels of VOCs detected at Area B and off site (that is, outside of the IRP site). Fourteen metals have also been detected at concentrations exceeding their drinking water CVs in shallow groundwater near Area B (see Appendix A), but the metals are thought to be present in soil suspended in groundwater, not in the groundwater itself. In addition, north of C Street, the pesticides dieldrin (reaching 0.94 µg/L) and gamma-hexachlorocyclohexane (0.15 µg/L) were detected at concentrations exceeding their CVs (0.002 µg/L and 0.1 µg/L, respectively) (Baker 1994b, c, d; CH2MHILL 1998b, 2000e, 2001b).
Detected levels of most contaminants in shallow groundwater have been higher north of C Street than south of it. VOCs extend as far as a drainage ditch about 150 feet south of the Camp Allen Elementary School, which is believed to serve as a hydrogeologic barrier, as it receives shallow groundwater discharge. Although the drainage ditch is thought to serve as a hydrogeologic barrier to the southward migration of groundwater contamination, 1991 sampling activities revealed shallow groundwater contamination south of the drainage ditch, at the northern end of Bright Street. This area is within the Capehart Military Housing Area, part of which os within NSN. Geoprobe sampling for trichloroethylene (TCE), 1,2-dichloroethene (1,2-DCE), and benzene conducted as part of the remedial investigation (RI) for the Camp Allen Landfill revealed concentrations of TCE reaching 79 µg/L (above the CV of 5 µg/L) and concentrations of 1,2-DCE reaching 36 µg/L (below the CV) in this area in 1991. A seepage area associated with the contamination was identified at that time on the southern bank of the drainage ditch that is south of the Camp Allen Elementary School. The source of the contamination is not known, but it is not thought to be associated with Camp Allen Landfill or Salvage Yard (Baker 1994b, c).
After the contamination was detected, the Navy installed several monitoring wells within and near the Capehart Military Housing Area to better characterize the nature of contamination. In samples collected from two monitoring wells just north of the drainage ditch behind the school, six VOCs have been detected at concentrations exceeding CVs: vinyl chloride (780 µg/L), TCE (510 µg/L), 1,1-dichloroethene (1,1-DCE, 51 µg/L), 1,2-dichloroethane (1,2-DCA, 120 µg/L), total 1,2-DCE (418 µg/L), and benzene (20 µg/L). For the most part, concentrations were highest in samples collected in 1992 and have declined in samples collected in subsequent years. The absence of VOCs in a monitoring well between the drainage ditch and groundwater contamination emanating from Area B of the Camp Allen Landfill indicates that the landfill is not the source of contamination. A shallow aquifer monitoring well south of the drainage ditch did not contain detectable levels of VOCs when it was sampled in 1992 and 2001. The houses in the Capehart Military Housing Area are south of the drainage ditch, and there are no known wells in the area. Shallow groundwater would be expected to migrate away from the houses and towards the drainage ditch to the north. Any shallow groundwater contamination that reaches the deep aquifer is expected to be captured by the deep extraction wells in Camp Allen Area B (Baker 1994b; Johnson 2002; CH2MHILL 1998b, 2000e, 2001b).
At the CD Landfill, deep groundwater in the Yorktown Aquifer is thought to flow (on the basis of data from the Camp Allen Landfill) to the north or northwest. No off-site groundwater samples have been collected near this site. Only one well at the CD Landfill site itself was screened in the deep aquifer, and when it was sampled in 1993, only two metals were detected at concentrations slightly exceeding their CVs: arsenic (detected at 2.8 µg/L, compared to its drinking water CV of 0.02 µg/L) and lead (detected at 16.9 µg/L, compared to its CV of 15 µg/L) (Baker 1995b). These levels, however, might be naturally occurring and would not result in adverse health effects to people with limited exposure to them.
Deep groundwater contamination originating from Camp Allen Landfill Area A extends west and north of the site, in both Area A1 and Area A2. Sampling data suggest that the deep groundwater contamination in Area A2, north of Area A, is about 1,000 feet from the nearest wells, which were used by Global Technology Systems, but are reportedly no longer in use. In the 1980s, when the two wells were still being used for industrial purposes, a deep monitoring well was installed near them to determine if contaminants from the Camp Allen Landfill were affecting these wells. Results from three samples collected from the monitoring well in 1983, 1984, and 1986 did not indicate that contamination originating in the Camp Allen area had reached this area. Only the 1983 sample contained detectable levels of any VOCs. In that sample, methylene chloride was detected at a concentration of 17 µg/L, which exceeds its CV (5 µg/L), and toluene was detected at a concentration of 18 µg/L, less than one-tenth of its CV (200 µg/L). Cadmium (30 µg/L), lead (140 µg/L), and thallium (100 µg/L) were also detected at concentrations exceeding their CVs (2 µg/L, 15 µg/L, and 0.5 µg/L, respectively) in the 1983 and 1986 samples (Pirnie 1988; CH2MHILL 2001b).
VOCs and metals were detected at levels exceeding CVs in the deep aquifer monitoring wells in Area A2 during the RI for the Camp Allen Landfill. In samples north of the site, the metals found at levels exceeding CVs and their maximum detected concentrations were: arsenic (26.7 µg/L, CV = 0.02 µg/L), iron (62,400 µg/L, CV = 11,000 µg/L), lead (15.3 µg/L, CV = 15 µg/L), manganese (1,010 µg/L, CV = 500 µg/L), thallium (6 µg/L, CV = 0.5 µg/L), and vanadium (103 µg/L, CV = 30 µg/L). The VOCs detected at concentrations exceeding CVs in samples collected during the RI and in subsequent available samples collected through 2001 are summarized in Table 4. VOC concentrations have been declining over time.
Currently, VOC contamination also appears to extend approximately 500 to 750 feet west of Area A1. VOCs have been detected in several monitoring wells that draw deep groundwater from locations within Glenwood Park, east of Bousch Creek Avenue, as well as two locations north of these wells. There is an extraction well that pumps and treats contaminated groundwater from the deep aquifer between Area A1 and the drainage ditch to its west, as well as an extraction well just south of the terminus of Beechwood Avenue. There are also two inactive extraction wells located between Area A1 and the drainage ditch. Sampling results indicate that concentrations of VOCs have been declining in this area since 1992, at least in part as a result of the Camp Allen Landfill groundwater treatment system (Baker 1994b, c, d; CH2MHILL 2001b). VOCs detected at concentrations exceeding CVs in locations west of Area A1 are summarized in Table 4.
VOC contamination in the deep aquifer is also present southeast of Camp Allen Landfill Area B. The source of VOCs is thought to be subsurface contamination in Area B in an area where the confining layer between the Columbia and Yorktown Aquifers is absent. The highest levels of VOCs in the deep Yorktown Aquifer have been detected along the southeastern portion of Area B. Three extraction wells east of Area B treat groundwater from the deeper aquifer. VOCs that have been detected southeast of Area B at concentrations exceeding CVs are presented in Table 4. Dieldrin was also detected at a concentration (0.009 µg/L) that exceeded its CV (0.002 µg/L) in an off-site sample collected east of Area B, north of C Street (Baker 1994b, c, d; CH2MHILL 2001b).
Evaluation of Potential Public Health Hazards
The only wells identified near the site that draw water from the shallow aquifer are in the Glenwood Park community. Water from these wells is used only for watering lawns and other outdoor uses, not for drinking water. Because there is a drainage ditch between the Camp Allen Landfill and the residential area that is thought to serve as a hydrogeologic barrier, and on the basis of one round of sampling, wells in Glenwood Park are not thought to be affected by contamination from the Camp Allen Landfill. Groundwater quality and use in Glenwood Park is discussed in further detail in the "Community Health Concerns" section of this public health assessment. Any past, current, or future exposures to contaminants are not expected to cause adverse health effects because the wells are not used for drinking water, sampling revealed very low levels of VOCs in only a few wells, and the area is not thought to be affected by Camp Allen Landfill groundwater contamination. The small amounts of VOCs detected would not accumulate in any vegetables grown in backyard gardens. Therefore, exposure to shallow groundwater poses no public health hazard.
The only wells drawing from the deep aquifer potentially downgradient of NSN groundwater contamination are used only for industrial purposes. Additionally, these wells are not currently affected by hazardous levels of groundwater contaminants. Sources of deep groundwater contamination are being remediated. Thus, exposure to deep groundwater poses no public health hazard.
Does exposure to fish and shellfish from Willoughby Bay pose a public health hazard?
ATSDR reviewed all available surface water, sediment, and aquatic biota (i.e., fish and shellfish) samples collected in Willoughby Bay, analyzed from 1971 to 2001. ATSDR also reviewed available information about potential fish and shellfish consumption patterns. ATSDR then estimated the potential doses using very conservative assumptions that would most likely overestimate the levels of actual exposure. On the basis of these calculations, ATSDR concludes that exposures to levels of contaminants detected in samples of fish and shellfish from Willoughby Bay would not be expected to result in adverse health effects. Although data gaps reflecting past seafood consumption patterns and past concentrations of contaminants to which people may have been exposed make it difficult to draw definite conclusions about past exposure, sampling conducted in 2001 by VDEQ indicated that levels of contaminants in fish and shellfish species to which people are exposed do not present a current or future public health hazard. Appendix C provides a detailed explanation of the evaluation process used to make this determination.
Wastewater and stormwater management requirements are expected to reduce contaminant levels reaching the bay over time. Available samples suggest that levels of most contaminants detected at concentrations above screening values are declining, except arsenic and zinc. Finally, ATSDR concurs with the recommendation of EPA's Chesapeake Bay Program for further study of contamination in Willoughby Bay.
Willoughby Bay Use
Fishing and crabbing reportedly are popular in Willoughby Bay and the Norfolk area in general. Fish species that are abundant in the bay include croaker and spot, among others. Most edible fish in the bay reportedly migrate within the Chesapeake Bay watershed, if not across an even wider area. This characterization does not apply to eel or shellfish (O'Reilly 2000). Beginning in 1975, people were not allowed to fish in Willoughby Bay due to a ban on fishing in the James River from Richmond to the Hampton Roads Bridge-Tunnel, north of Willoughby Bay. The ban resulted from the illegal dumping of kepone (an insecticide) in the James River in Hopewell, which is more than 50 miles from NSN. The ban on sportfishing was lifted in 1980. Restrictions on the commercial harvesting of individual fish species were lifted, beginning in 1981, and the ban was lifted in its entirety in 1988 (Alliance for the Chesapeake Bay 1995; Barron 2001a). On July 1, 1988, the following fish advisory was issued for the area that had previously been affected by the fishing ban, "Kepone may be hazardous to your health. A fish-eating advisory exists for those who consume fish from these waters on a daily basis" (VDOH-DHHC 1988). ATSDR did not observe any signs publicizing this advisory during its site visits.
Locations from which people fish and crab in the bay include a marina near the southwestern tip of Willoughby Spit and a small pier about ½ mile east of the marina (LeBleu 1996). The Virginia Marine Resources Commission (VMRC) requires people who plan to catch finfish or shellfish in the tidal waters of Virginia to purchase licenses for their gear, which they must renew annually. For certain species, there are restrictions on the minimum size and/or the maximum number an angler may take. In addition to licenses, permits are required to commercially harvest several marine species (including crabs) or to use certain types of gear (VMRC n.d.).
Since 1973, the VMRC has collected data on the number of pounds and the dollar value of the commercial seafood harvest in Willoughby Bay. From 1973 to 1992, reporting by dealers was voluntary. Hence, data are not complete. Since 1993, fishermen have been required to report this information about their catch. The VMRC indicates that between 10,000 and 60,000 pounds of blue crabs from Willoughby Bay have been reported harvested annually since 1976. The 1999 blue crab harvest was almost 45,000 pounds. The fish most commonly commercially harvested from Willoughby Bay, according to VMRC data, is grey seatrout. However, the number of pounds of grey seatrout commercially harvested annually has varied since 1994 from less than 50 pounds to more than 1,200 pounds. In a few years, there have been commercial spot and alewife harvests; the highest number of pounds of spot harvested in a year was about 1,325 in 1996 and of alewife was about 2,250 in 1997 (VMRC 2001).
Shellfishing is prohibited along the entire length of the Elizabeth River and its tributaries, including Willoughby Bay, due to concerns about bacteriological contamination (Virginia Department of Health 1997). This prohibition does not apply to blue crabs. Furthermore, hard clams (also called quahogs) and oysters may be harvested from Willoughby Bay and waters within the shellfish condemnation area if the shellfish are relayed to an uncontaminated location for a minimum of 15 days. That is, shellfish may be collected from Willoughby Bay, moved by parties with permits from the VMRC in approved containers to uncontaminated areas for 15 or more days, then washed and processed for sale (VMRC 2000). According to VMRC data, the annual hard clam harvest from Willoughby Bay has ranged from 700 pounds to 3,300 pounds, except in 1996, when no hard clams were harvested. However, no commercial harvest of oysters from Willoughby Bay has been reported for any year since 1973 (VMRC 2001).
During its 1998 site visit, ATSDR observed several people fishing from the bulkheads (sea wall) near the confluence of Bousch Creek and Willoughby Bay (at the intersection of Aircraft Tow Way and Bellinger). In this area, the Virginia Department of Health had posted signs allowing fishing, but banning shellfish harvesting (ATSDR-DHAC 1998a). Fishing in this area, apparently by civilian employees of the NSN, was also observed in 1995 (Baker 1996a). There reportedly is a fishing pier on the eastern (Willoughby Bay) side of the northwestern tip of the base. Also, the Norfolk Naval Sailing Center rents motorboats, which may be used for fishing in Willoughby Bay, to military personnel and their families (Norfolk Naval Sailing Center 2000).
In 1997, the Navy reportedly opened a park in the northeast corner of the base, opposite the aircraft carrier piers. The park, referred to as "Salt Marsh Park," was designed to manage stormwater, attract wildlife, and provide recreational opportunities, and it includes about 1 acre of wetlands. Military and civilian personnel who fish at the park reportedly can catch fish, including bluefish and flounder, in the lagoon, which opens into Willoughby Bay (Army Corps of Engineers 1998).
Nature and Extent of Contamination
Contaminants from IRP sites, on-base industrial areas, spills, and groundwater contamination from NSN have been transported to Willoughby Bay, since runoff and drainage from much of the base discharges to Bousch Creek and Mason Creek, which both empty into the bay. In the past, industrial wastewater from the base was also discharged to the storm sewer system, which discharged to Willoughby Bay. In the mid-1970s, most of the industrial wastewater was rerouted to the NSN Industrial Wastewater Treatment Plant, which discharges to the Hampton Roads Sanitation District sewage treatment plant. The remaining discharges from the storm sewer system to Willoughby Bay are permitted and monitored (Baker 1993). Prior to the permitting of discharges to Willoughby Bay, contaminants entering the bay were not monitored. Moreover, the levels of contaminants contributed to the bay by other activities at NSN are unknown.
Other potential sources of contamination within Willoughby Bay include petroleum products from boats and ships and creosote from wood preservatives in pilings (Swihart 2000). Storm drains from Willoughby Spit might also discharge to Willoughby Bay. Water quality in the bay is also thought to be significantly influenced by water from Hampton Roads (the confluence of the James and Elizabeth rivers), which is carried into Willoughby Bay by outgoing tides (Boon 2001). Since there are significant sources of contamination in both rivers, the contribution to surface water contamination in Willoughby Bay from NSN, as opposed to other sources, would be difficult to determine. ATSDR also notes that many edible fish in Willoughby Bay reportedly migrate within the Chesapeake Bay watershed, if not across a wider area (O'Reilly 2000).
In 1999, an EPA Chesapeake Bay Program report characterizing the tidal rivers that flow into the Chesapeake Bay designated the lower tidal portion of the James River as an "Area of Emphasis, with special concern for Willoughby Bay." This designation indicates that living resources (including fish and shellfish) in the lower James River and in Willoughby Bay might be affected by chemical contamination, primarily from metals. Laboratory tests showed that surface water and sediment from Willoughby Bay caused adverse effects to living organisms and was more detrimental than surface water and sediment from most of the 46 other stations in the tidal rivers from which samples were drawn. As previously noted, the Chesapeake Bay Program had designated the Elizabeth River a "Region of Concern" in 1993, indicating that it was an area where there was a probable chemical contaminant-related problem (EPA Chesapeake Bay Program 1999).
In order to assess the quality of Willoughby Bay and the potential human health effects of any contamination, ATSDR collected and reviewed all the surface water, sediment, and edible aquatic biota sampling data from the bay that could be located. For initial screening, concentrations of contaminants in biota samples were compared to CVs for fish. Available surface water and sediment data were compared to drinking water and surface soil CVs, respectively, because no surface water or sediment CVs are available. These comparison values are used as a conservative screening method. Recreational exposures to surface water and sediment in Willoughby Bay would occur much less frequently than the long-term daily exposure assumed by the CVs. Moreover, Willoughby Bay is not used for drinking water and incidental ingestion of water from Willoughby Bay would result in exposure doses significantly lower than those assumed by drinking water CVs.
ATSDR identified 18 surface water samples collected from Willoughby Bay between 1972 and 1984, as well as a 1995 sample. Most of the samples were drawn from the center of the mouth of Willoughby Bay, but several were drawn from locations near the eastern end of IRP Site 13, the Past Industrial Wastewater Outfalls. Most of the samples were analyzed for metals, and several metals were detected at concentrations slightly exceeding drinking water CVs in the samples from the mouth of Willoughby Bay (see Table 5). Several of the samples were also analyzed for pesticides, and two of the samples were analyzed for PCBs. Neither pesticides nor PCBs were detected in these samples (EPA Chesapeake Bay Program 1998; STORET 2001).
ATSDR identified 17 sediment sampling events conducted in Willoughby Bay, most of which occurred prior to 1988. Samples were analyzed for polycyclic aromatic hydrocarbons (PAHs), PCBs, selected pesticides, and metals. Several sets of samples were collected along IRP Site 13 (where the highest levels of most contaminants were found). Four samples were collected adjacent to Site 12, an alleged mercury disposal site, and others were collected farther from shore. No pesticides were detected at concentrations above soil CVs. PAHs, PCBs, and metals detected at concentrations exceeding their CVs are listed in Table 5 (Baker 1996a, c; EPA Chesapeake Bay Program 1998; MAIA 1997; STORET 2001; VDEQ-CBP 1981; VDEQ-WDG 1987; VDEQ-WQS 1998).
Two sediment samples and three surface water samples from the lagoon adjacent to Willoughby Bay (now part of Salt Marsh Park) were collected in the mid-1990s. In the sediment samples, benzo(a)pyrene (1.2 milligrams/kilogram [mg/kg]), benzo(b)fluoranthene (2.1 mg/kg), and arsenic (8.6 mg/kg) were present at concentrations exceeding their CVs (0.1 mg/kg, 0.87 mg/kg, and 0.5 mg/kg, respectively). In the surface water samples, three metals were present at concentrations exceeding their CVs: cadmium (7.6 µg/L, CV = 2 µg/L), iron (14,700 µg/L, CV = 11,000 µg/L), and lead (145 µg/L, CV = 15 µg/L) (Baker 1996c).
Over the last 30 years, VDEQ and VDOH's Division of Shellfish Sanitation (VDSS) have collected and analyzed fish and shellfish samples from several locations in Willoughby Bay. In summer 2001, VDEQ conducted a round of sampling during which it analyzed composite samples of blue crab, croaker and spot (edible fish), oyster, and hard clam tissue. VDEQ analyzed composite samples for PAHs, pesticides, PCBs, and selected metals (arsenic, cadmium, chromium, mercury, lead, selenium, thallium, and zinc). Prior to 2001, most fish and shellfish samples had been analyzed for a more limited range of contaminants, and many of the past sampling events were focused on oysters, rather than other seafood species that people are thought to be more likely to consume. The results of all identified fish and shellfish sampling events (from both VDSS and VDEQ) are summarized in Table 6 (EPA Chesapeake Bay Program 1999; STORET LDC 2001; VDEQ-CBP 1987; VDEQ-WQS 1998, 2001; VDOH-DSS 2000).(1) Some of the data are presented below.
Oyster samples (most comprised of 10 individual oysters) have been analyzed for metals by VDSS at least biannually since 1974. These samples are collected south of the eastern end of Willoughby Spit. Results from VDSS oyster samples suggest that cadmium, chromium, and lead levels have decreased over time. Virtually all oyster samples collected since 1985 have contained levels of these metals below 1 mg/kg. (One 1987 sample contained 3.1 mg/kg of cadmium; two 1986 and two 1998 samples contained 1.3 mg/kg, 2.1 mg/kg, 10.3 mg/kg, and 74 mg/kg of chromium, respectively; and a 1990 and 1993 sample each contained 2 mg/kg of lead, while one 1986 and two 1987 samples contained <1.9 mg/kg, <2.5 mg/kg, and <2 mg/kg of lead, respectively.) VDEQ biota samples collected in summer 2001 from the center of Willoughby Bay also contained very low levels of cadmium, chromium, and lead. For the 2001 oyster sample, results were reported as <0.01 mg/kg cadmium, <0.05 mg/kg chromium, and 0.13 mg/kg lead. Levels of these three metals in samples from other seafood species (clams, crabs, and fish) have also been relatively low (VDOH-DSS 2000; VDEQ-WQS 1998, 2001).
Arsenic levels in VDSS samples have ranged from an average of 1.2 mg/kg between 1985 and 1989, to an average of 1.4 mg/kg between 1990 and 1994, to an average of 1.71 between 1995 and 2000. These concentrations are all below levels of public health concern. A 2001 VDEQ oyster sample contained <0.5 mg/kg of arsenic. The 2001 VDEQ samples from other species also contained <0.5 mg/kg of arsenic, as did a 1998 VDEQ spot sample. A 1998 VDEQ crab sample contained 1.1 mg/kg of lead (VDEQ-WQS 1998, 2001). Average copper levels have also consistently been below levels of health concern (reaching only 48 mg/kg in VDSS samples). Zinc levels in Willoughby Bay oysters have ranged from an average detected concentration of zinc was 608 mg/kg in samples collected from 1971 through 1980, to an average of 635 mg/kg in samples collected from 1981 to 1990, to an average of 728 mg/kg in samples collected from 1991 to 2000 (VDOH-DSS 2000). In a 2001 oyster sample, VDEQ measured 208 mg/kg of zinc (VDEQ-WQS 2001). This concentration would not be expected to cause any adverse health effects. Furthermore, there has been no known oyster harvesting in Willoughby Bay since 1972 (VMRC 2001).
Other sampling events include the analysis of sixteen blue crab claw samples (from up to five individual crabs) between 1978 and 1980 by VDEQ for 4,4'-DDE. Between 1971 and 1974 and in 1986 and 1987, VDEQ analyzed several samples from oysters and hard clams for metals, PCBs, selected PAHs, and selected pesticides, as well as two spot samples and a blue crab sample for metals. These samples were collected from locations near the eastern end of IRP Site 13. The most recent sampling events were the 1998 collection, by VDEQ, of a blue crab and a composite spot sample near the center of Willoughby Bay (and analyzed them analysis of these samples for PAHs, pesticides, PCBs, and six metals) and the 2001 sampling event previously described (EPA Chesapeake Bay Program 1999; STORET LDC 2001; VDEQ-CBP 1987; VDEQ-WQS 1998, 2001; VDOH-DSS 2000).
Evaluation of Potential Public Health Hazards
Levels of contaminants in Willoughby Bay would be expected to have been highest prior to the mid-1970s, when industrial wastewater from NSN drained directly to Willoughby Bay. The institution of wastewater and stormwater management measures would be expected to result in a decline in levels of contaminants reaching the bay in subsequent years. For the most part, available fish and shellfish samples have shown a decline in contaminant levels over time. VDEQ conducted its most recent round of sediment and biota sampling in summer 2001. In response to ATSDR's recommendations, VDEQ sampled crabs, fish, clams, and oysters. All biota samples were analyzed for organics and metals, including arsenic, thallium, and zinc. (VDEQ-WQS 2001).
To evaluate whether health hazards might be associated with exposure to fish and shellfish, ATSDR estimated potential doses from consuming fish and shellfish using very conservative assumptions that will tend to overestimate the levels of actual exposure. These assumptions, ATSDR's methods, and the estimated doses are further described in Appendix C. The only available samples that reflect past concentrations of zinc in seafood samples other than oysters, which are thought to be harvested from Willoughby Bay, are four samples of crab, clam, and spot, three collected in 1971 and one in 1986. These samples contained levels of zinc that might cause short-term, reversible effects--temporary and reversible gastrointestinal distress or decreases in levels of serum cortisol(2)--under acute exposure scenarios. The small number of samples analyzed 15 to 30 years ago and the limited information on past fish and shellfish consumption patterns are not sufficient for a definitive evaluation of the likelihood that past levels of zinc in fish and shellfish might have caused adverse health effects. On the basis of our calculations using conservative assumptions, ATSDR concludes that, with the exception of the possibly elevated zinc levels, no adverse health effects would be expected to result from exposures to the levels of contaminants detected in fish and shellfish samples from Willoughby Bay. In the most recent samples that ATSDR evaluated, only oysters were found to contain zinc levels sufficiently high to cause adverse health effects (VDEQ-WQS 2001). Since there is no known oyster harvest from Willoughby Bay, there is no apparent public health hazard from current or future consumption of Willoughby Bay fish and shellfish. ATSDR concurs with the Chesapeake Bay Program's recommendation for further study of contamination in Willoughby Bay.
A community relations plan for NSN provides guidance for keeping the community informed about site-related activities and involving the community and other interested parties in the decision-making process for selecting remedial alternatives. Public meetings are held to inform citizens of ongoing remedial activities and to solicit their input. Navy officials also have given community presentations and are available to discuss any concerns that community members have. The public may review site-related documents, including RI reports and correspondence relating to cleanup activities, at a repository at:
Kirn Memorial Branch
Norfolk Public Library
301 East City Hall Avenue
Norfolk, VA 23510
A RAB composed of representatives of the Navy, EPA, the Commonwealth of Virginia, local agencies, and community groups meets regularly to discuss and review ongoing activities at NSN. Two concerns were conveyed to ATSDR during the July 1998 RAB meeting: discolored drinking water from a cooler at an on-base hangar and flooding of a residential yard in Glenwood Park. ATSDR evaluated available information about drinking water from on-base fountains and coolers, which is supplied by the city of Norfolk, and concluded that the discoloration was a short-term occurrence that would not be expected to pose a public health hazard. ATSDR and Navy personnel visited the flooded yard, which was receiving water overflowing from a nearby pond, and agreed that the cause of the flooding should be identified to avert any possible safety hazard. A subsequent assessment indicated that localized flooding occurred in many parts of Norfolk as a result of a major storm that hit the area (Bridges, 2001).
Through meetings, contact with officials and the public, and its review of site documents, ATSDR has identified the following community health concerns:
- Is the cancer rate in Glenwood Park elevated?
- Is groundwater contamination originating from NSN affecting private wells in Glenwood Park?
- Does discolored drinking water from a drinking water cooler at one of the base hangars or metals in other on-base sources of drinking water pose a health hazard?
- Are on-base residents exposed to lead-based paint or asbestos?
- What are the public health implications of exposure to emissions from former incinerators, open burning areas, boilers, and/or smelters?
- Do exposures to children in the vicinity of the Camp Allen Elementary School pose a public health hazard?
According to an analysis of all reported cancer-related deaths and illnesses performed by the Virginia Department of Health's Office of Epidemiology, the death rate from all cancers in Glenwood Park was lower than that in three Norfolk communities studied for comparison. A subsequent analysis of specific cancer deaths, based on names of Glenwood Park residents reported to have had cancer, indicated that there were not an excess number of cancer cases in Glenwood Park, nor were there any "cancer clusters" (i.e., groupings of related cancer incidents) in the neighborhood (Woolard 1990, 1991; Baker 1993).
Samples from groundwater monitoring wells at the Camp Allen Landfill have contained VOCs at levels exceeding safe drinking water standards. Although homes in Glenwood Park receive drinking water from the city of Norfolk, there are at least 58 homes with private wells used for watering lawns and gardens, filling pools, and/or other outdoor uses. These private residential wells reportedly draw water from the shallow aquifer. The Navy sampled 57 of the wells for VOCs (55 in 1991 and two in 1992) and planned to sample the 58th well, but could not because its pump was broken.
Low levels of VOCs were found in five of the private well samples, but each detection appears to be an isolated incident. Each of the five wells was adjacent to other wells that did not contain detectable levels of VOCs. Two of the 1991 samples contained 2-butanone (also known as methyl ethyl ketone) at concentrations of 10 µg/L and 76 µg/L, respectively. Another sample contained 4 µg/L of acetone, which might have been a laboratory contaminant, since acetone was detected in the blank sample, but not a duplicate sample from the same location. The levels of 2-butanone and acetone that were detected were well below ATSDR's comparison values.
One well sample contained 10 µg/L of PCE, a concentration equal both to the laboratory detection limit for the sample and its drinking water CV. Another sample contained 38 µg/L 1,2-DCA, a concentration that exceeds its CV of 0.4 µg/L (Baker 1994b). PCE is a common byproduct of dry cleaning and industrial metal cleaning or finishing operations. It also can leach into water from the vinyl liners of some types of water pipelines. 1,2-DCA can be found in plastics, rubber and synthetic textile fibers, certain solvents, and is used in making other organics, among other products (EPA 1998).
While the detected concentrations of PCE and 1,2-DCA in two private wells in Glenwood Park exceed certain drinking water screening values, the screening values are based on the assumption that people drink 2 liters of contaminated water per day. Wells in Glenwood Park are not used for drinking water. Thus, residents would be expected to have incidental, infrequent skin contact with contaminated water, which would not be expected to cause adverse health effects at the detected levels.
The Navy has sampled a shallow monitoring well it installed at the eastern end of Glenwood Park, between the terminus of Beechwood Avenue and the drainage ditch to its east. A March 1991 sample from this well contained between 1 and 2 µg/L of total xylenes, toluene, PCE, and benzene. It also contained less than 10 µg/L of acetone and methylene chloride, both detected in the sample blanks and possible laboratory contaminants. Of these detections, only the benzene level and the methylene chloride level exceeded CVs (0.6 µg/L and 5 µg/L, respectively). June 1992 and December 1993 samples from the same location did not contain detectable levels of VOCs (Baker 1994b, c).
Additional samples from monitoring wells drawing shallow groundwater west of the drainage ditch are not available. Any contamination present in Glenwood Park wells is not expected to be attributable to the Camp Allen Landfill because there is a drainage ditch between the landfill and the residences that is thought to serve as a hydrogeologic barrier. Samples from several monitoring wells located between the landfill and Glenwood Park do not show a connection between groundwater contamination in the two areas. Furthermore, shallow and deep groundwater are thought to be hydraulically connected in the area, and concentrations of VOCs in deep monitoring wells in the area have declined since the Camp Allen Landfill groundwater treatment system began operating. Therefore, the groundwater treatment system appears to be successfully drawing any VOCs from the shallow aquifer to the deeper aquifer and eastward towards the extraction wells (Baker 1994b, 1995a; CH2MHILL 2001b; Johnson 2002).
At the July 1998 RAB meeting that ATSDR attended, a base employee inquired about discolored drinking water at building SP-31, a hangar. Base personnel, like other water system users, have sometimes observed discolored water coming from water coolers or faucets. Drinking water is provided to the base from the city of Norfolk's 37th Street Plant. Water samples are analyzed regularly at the plant before the water is distributed, in compliance with the Safe Drinking Water Act (SDWA). No violations of SDWA standards occurred in 1999 or 2000 (City of Norfolk 2001).
If the Navy Public Works Center receives any complaints of discolored drinking water, it advises people to first flush the water in their taps. If the problem persists, Public Works personnel investigate and address the source of the problem (Din 2000). Similarly, when the city of Norfolk's Department of Utilities is notified of discolored water in city lines, it identifies the source of the problem and addresses it.
According to the city of Norfolk's Division of Water Quality, water discoloration commonly results from particles resting on the bottom of pipes being picked up by water traveling through pipes and carried along with the water. This might occur after a water line disturbance, such as water line maintenance, or any other circumstance that causes water to travel through pipes at a higher velocity than normal. Discolored drinking water typically is not considered to pose a health risk, but the city of Norfolk recommends that users not drink temporarily discolored water until it is clear again (City of Norfolk 2001; EPA 1992).
Lead, copper, and other metals present in water distribution systems can leach into drinking water. Several measures have been implemented to reduce the potential for exposure to metals in drinking water. Since approximately 1990, the city of Norfolk has added zinc orthophosphate to the water it distributes. This compound creates a protective film along the walls of pipes, reducing the potential for corrosion (which allows metals to leach into water) (Land 2000). In the early 1990s, the Navy implemented a program to measure lead levels in a sample from each on-base water fountain or cooler located in a "priority area" (base housing, food preparation area, or medical facility). The program required that measures be taken to address any elevated lead levels found, such as the replacement of the affected fountains (Office of the Chief of Naval Operations 1994). In addition, old water mains throughout the base that might have contained lead joints are being replaced over time (Din 2000).
The Navy provided ATSDR with the results of lead sampling conducted at drinking fountains at base hangars. Fifty-four of the 60 samples ATSDR reviewed contained levels of lead below 15 µg/L, EPA's action level and ATSDR's drinking water CV. The other six samples were collected from hangars LP-14 and LP-4. Lead levels exceeding the CV were detected in four of the ten 1994 samples from LP-14 (17 µg/L, 72 µg/L, and 160 µg/L in samples collected on the same day from one fountain and 38 µg/L in a sample from another fountain). When the fountain where elevated levels were detected in three samples was resampled the following day, the lead level was only 12 µg/L. Samples collected in 1989 from fountains in the building had not contained lead levels exceeding the CV. LP-14 was demolished in 1996. The detections of lead in the water from LP-14 fountains are unlikely to have resulted in adverse health effects, as exposures to base employees would have been limited. Two of 12 samples collected from fountains at LP-4 in 1989 and 1991 contained levels of lead less than three times the CV. These levels would not be expected to cause adverse health effects under the expected exposure scenarios (Heaney 1999).
No sampling data from fountains or coolers at hangar SP-31, about which the employee had expressed concern in July 1998, were provided to ATSDR. In addition, the Public Works Department does not have records of any complaints received about fountains or coolers at the hangar in question around that time (Navy Public Works Center 2000). Thus, ATSDR expects that the discolored drinking water present in building SP-31 was a short-term occurrence and did not pose a public health hazard. As noted earlier in this document, the Navy and the city of Norfolk take measures to protect the quality of drinking water provided to base employees and their families.
The Navy also provided ATSDR with data from sampling it conducted in compliance with the EPA's Lead and Copper Rule, which requires that the concentration of each metal exceed the appropriate EPA action level in less than 10% of samples analyzed. This sampling program targets faucets in Navy facilities, which would not be expected to be common sources of drinking water, not drinking fountains or coolers. Taps from 60 locations throughout the base were sampled biannually from 1992 to 1998; during each sampling event, levels of lead and copper exceeded EPA action levels in fewer than 10% of samples, in compliance with the Lead and Copper Rule. Thus, annual monitoring has been reduced to 30 locations. NSN's 1999 and 2000 sampling also complied with the rule. However, since 1992, there have been sporadic instances in which lead and copper levels in individual samples have exceeded CVs (Navy Public Works Center 2000; NSN n.d.b.; VDOH-OWP 2000). In most locations, these instances were isolated, and any exposures to elevated levels of lead and copper in water from these faucets would be sufficiently infrequent that they would not result in adverse health effects.
The only building where lead or copper levels seem to regularly exceeded CVs (15 µg/L for lead and 1,300 µg/L for copper) is Building Z-103. The lead level in the first sample collected from the faucet, in 1992, was 114 µg/L. Two 1993 samples contained 35 µg/L and 65 µg/L lead, respectively. In subsequent samples collected biannually from 1994 to 1998, samples collected between January and June contained levels of lead below the CV, but samples collected between July and December contained levels of lead ranging from 16 µg/L to 34 µg/L. While no samples were collected from this faucet in 1999, a sample collected in the second half of 2000 contained only 2 µg/L lead. Copper levels measured in this location have consistently been below the CV.
While lead and copper levels exceeded CVs from 1993 to 1996 at the location sampled in the Marine Corps Exchange (MC-1), concentrations measured in samples collected since 1996 have been below levels of health concern. The levels of lead and copper did not exceed CVs in one sample collected in 1992. Lead levels ranged from 78 to 105 µg/L in four 1993 and 1994 samples, dropped to 14 µg/L in a winter 1995 sample, rose to 208 µg/L in a summer 1995 sample, then dropped to 36 µg/L in winter 1996 and 5 µg/L in summer 1996. Copper levels in samples from the faucet at MC-1 exceeded the CV in 7 of 8 samples collected from 1993 to 1996. Concentrations during the eight sampling events were as follows: 3,450 µg/L; 1,680 µg/L; 20 µg/L; 3,060 µg/L; 6,000 µg/L; 3,600 µg/L; 1,700 µg/L; and 2,620 µg/L. A sample collected each year from 1997 to 2000 did not contain concentrations of either metal at levels of health concern (Navy Public Works Center 2000; NSN n.d.b.; VDOH-OWP 2000).
Faucets are not expected to be regular, frequent sources of drinking water at NSN. Under short-term and infrequent exposure scenarios, the detected levels of lead and copper would not be expected to cause adverse health effects. However, as a precautionary measure, ATSDR recommends that the Navy verify that the faucet sampled at Z-103 is not commonly used for drinking water. If the Navy determines that it is, ATSDR recommends that it be resampled. If levels of lead exceed CVs, ATSDR recommends that the Navy take appropriate measures to ensure that people are not exposed to these concentrations, either by remediating the sources of lead and/or copper or ensuring that the faucet is not used for drinking water.
During its 1998 site visit, ATSDR investigated the ways in which the Navy protects on-base residents from exposure to lead-based paint and asbestos. In accordance with its lead and asbestos management plans, the Navy has surveyed its housing units and identified those that contain lead-based paint or asbestos. Educational materials about exposure to lead paint are distributed to people moving into base housing. The Navy has affixed labels to crawl spaces and attics in base housing warning residents that these areas may contain asbestos and that residents should avoid breathing airborne asbestos fibers (Bridges 2000). Pediatricians serving the children of base personnel follow the Centers for Disease Control and Prevention's recommendations for screening the blood lead levels of young children. The results of 1999 and available 2000 blood lead screening did not show any children living in on-base housing with elevated blood lead levels (Olesen 2000). Because the Navy takes measures to ensure that there is no exposure to friable asbestos in housing and provides information to on-base residents about the potential risks of exposures to lead-based paint, ATSDR expects any residential exposures to be limited.
Several activities at NSN formerly generated air emissions. Air emissions were not regulated prior to the 1970s, and little information is available about these past sources (Johnson 2000). Site-related documents indicate that smelting and incineration at the Camp Allen Salvage Yard, incineration and open burning at the Camp Allen Landfill, burning of salvage fuel and other waste in a boiler, and aluminum smelting in the naval magazine (NM) area of the Naval Air Station were formerly conducted. ATSDR did not identify any ambient air samples collected at the times these activities were under way. Therefore, ATSDR focused its review on available information about the emissions sources.
In the southeast corner of the Camp Allen Salvage Yard, a smelter operated for about 30 years in the vicinity of Building CA220. Aluminum and lead were smelted, and debris from the smelter was usually transported to Area A of the Camp Allen Landfill for disposal. A small incinerator, reportedly used to burn insulation from copper wiring for reuse, was adjacent to the smelter (Baker 1994a). Because it has been some years since the smelter and incinerator operated, no additional information about the operations of these facilities is available (CLEAN 1999). During the preliminary assessment/site investigation for the Camp Allen Salvage Yard, one soil sampling location was selected to assess potential soil contamination at the former smelter and incinerator site. Neither the surface soil sample (0-6 inches) nor the subsurface soil sample (30-36 inches) contained detectable levels of most contaminants. Arsenic, detected at 1.9 mg/kg in surface soil and 3.8 mg/kg in subsurface soil, was the only contaminant detected at concentrations exceeding its soil CV (0.5 mg/kg). However, the arsenic concentrations detected in these samples were lower than concentrations measured in most other samples from the Salvage Yard area collected from corresponding depths, as were concentrations of other metals (Baker 1994a; CLEAN 1999).
An incinerator built in the southern portion of Camp Allen Landfill Area A in the mid-1940s operated until the mid-1960s. It was used to burn a variety of combustible wastes. Materials too bulky for the incinerator were burned in Area A. No records offering more detailed information about these activities are available. Incineration and open burning were relatively common practices at that time and were not regulated (Baker 1994c). Soil samples from Area A of the Camp Allen Landfill in 1992 contained three metals at concentrations exceeding CVs: arsenic (70 mg/kg, CV = 0.5 mg/kg), cadmium (89 mg/kg, CV = 10 mg/kg), and lead (683 mg/kg, CV = 400 mg/kg). Some samples also contained Aroclor-1260 (0.42 mg/kg, CV = 0.32 mg/kg) and benzo(a)pyrene (0.31 mg/kg, CV = 0.1 mg/kg). Aroclor-1260, a PCB, is unlikely to be associated with air emissions from burning activities. Benzo(a)pyrene was only detected after the landfill removal action and is a common contaminant that can be attributable to vehicle emissions. The elevated metals levels could be from past incineration activities (or from soil from nearby borrow pits used for landfill capping) (Baker 1994b), although there is no way to confirm this and the soil data do not permit estimates of past air emissions.
Documents generated during investigations of the NM Slag Pile indicate it received slag in the 1950s and 1960s that had been generated by aluminum smelting operations conducted in the NM area of the Naval Air Station (CH2MHILL 1997b). ATSDR did not identify any additional information about these operations. A unit known as the Salvage Fuel Boiler Plant operated from 1967 until 1986 in Building Z-309, northwest of the intersection of Admiral Taussig Boulevard and Virginia Avenue. It generated steam by burning salvage fuel, supplemented with residential and office waste. Although the plant ceased operating in September 1986, apparently due to violations of its state of Virginia air permit, it was reportedly upgraded in 1976 with electrostatic precipitators to meet air pollution control standards. AOC 1 includes the area where ash from the boiler was managed, as well as an adjacent area where oils and lubricants were stored. AOC 1 has been investigated by the Navy and determined not to require further action. Appendix A lists the metals and PAHs detected in surface soil in this area. These data, however, do not provide information about the concentrations of pollutants present in air when the boiler was operating (Kearney 1990; CH2MHILL 1999a).
The Navy has quantified current on-base sources of air emissions and applied for an operating permit for these sources pursuant to the Clean Air Act (CAA) (Naval Base Norfolk Environmental Department 1998). CAA permits are designed to minimize emissions and protect public health. The public will have the opportunity to review and comment on the draft permit before it is finalized.
People who are or were near operating sources of air emissions might be or have been exposed to airborne contaminants as they disperse, but the nature and extent of these exposures cannot be quantified. ATSDR has not identified any evidence of health concerns related to air emissions of base personnel or their families, or of members of the surrounding community. In the absence of data characterizing the amounts of contaminants released, ambient air concentrations to which people were or are exposed, and exposure frequency and duration, ATSDR cannot assess the public health implications of exposures to air emissions. In the future, emissions will be limited by pollution control equipment and the requirements of the CAA permit, and these measures are expected to keep emissions to levels that would not be of health concern.
In 1992, as part of the RI for the Camp Allen Landfill, soil, surface water, sediment, and air samples were collected in the vicinity of the Camp Allen Elementary School. Levels of environmental contaminants detected in this area are not expected to result in adverse public health effects.
Contaminants detected during these sampling events at concentrations exceeding CVs are presented in Table 7. Three soil samples collected northwest of the school were analyzed for metals. Arsenic, cadmium, and chromium were present at concentrations that exceeded CVs. The Navy reported that the detected concentrations of arsenic and chromium were probably naturally occurring and does not plan any follow-up sampling.
RI sampling activities included the collection of two surface water samples and three sediment samples from a drainage ditch near the school. The drainage ditch is not large enough to be used for swimming or fishing and goes dry periodically. Two sampling locations were used, one about 200 feet south of the school and the other more than 1,000 feet west of the school. The surface water sample collected south of the school contained only arsenic at a concentration exceeding its CV. The other surface water sample contained arsenic at a slightly higher concentration, as well as antimony, iron, lead, and manganese at concentrations exceeding their CVs. Two shallow and one deep sediment samples (collected from the same locations as the surface water samples) were analyzed for metals. In these samples, only arsenic was detected at concentrations exceeding its CVs (Baker 1994b, 1995a).
The Camp Allen Elementary School is partially fenced (Baker 1994c). Soil sampling locations were between the school and Area B of the Camp Allen Landfill. Children would not be expected to have regular and extended exposures to soil in these areas. Exposures to surface water and sediment in the drainage ditch would be expected to be infrequent and of short duration. ATSDR expects that infrequent exposures of short duration to the detected concentrations of metals in soil, surface water, and sediment would not result in adverse health effects.
Fifteen air samples were collected within the school in 1992. The only contaminants present at concentrations exceeding air CVs were benzene and hexachlorobutadiene. Benzene was present in all 15 samples from the school and from 15 samples collected near the landfill, at concentrations ranging from 0.4 µg/m3 to 0.7 µg/m3. Hexachlorobutadiene was present at a concentration of 0.3 µg/m3 in four samples (from three locations). The same concentration of the VOC also was detected in four of 15 ambient air samples collected in 1992 near the Camp Allen Landfill (Baker 1994b, 1995a).
Tobacco smoke, motor vehicle exhaust, and industrial emissions are sources of benzene, as well as vapors from products that contain benzene, including paints, glues, and detergents. Hexachlorobutadiene is produced from the synthesis of certain chlorinated hydrocarbons and is used in the production of rubber compounds. The maximum detected concentrations of benzene and hexachlorobutadiene in air samples were lower than levels reported in the scientific literature as causing adverse health effects. In addition, background levels of benzene are commonly more than five times higher than levels detected at the Camp Allen Elementary School (ATSDR 1994a, 1997).
At the time the air samples were collected, groundwater contamination was not thought to extend beneath the elementary school. If any future groundwater monitoring data indicate that substantial groundwater contamination is migrating underneath the school or other areas where people live, work, or go to school, ATSDR recommends the Navy evaluate the appropriateness of collecting additional indoor air samples.
If people have other concerns to share with ATSDR, they can call us at 1-888-42-ATSDR or write to: Chief, Program Evaluation, Records, and Information Services Branch, Agency for Toxic Substances and Disease Registry, 1600 Clifton Road (E-56), Atlanta, GA 30333.
ATSDR recognizes that infants and children might be more sensitive to exposures than adults in communities with contamination in their water, soil, air, or food. This sensitivity is a result of a number of factors. Children are more likely to be exposed to soil or surface water contamination because they play outdoors and often bring food into contaminated areas. Children are shorter than adults, which means they can breathe dust, soil, and any vapors close to the ground. Children also are smaller, resulting in higher doses of chemical exposure per body weight. The developing body systems of children can sustain permanent damage if toxic exposures occur during critical growth stages. Most importantly, children depend completely on adults for risk identification and management decisions, housing decisions, and access to medical care. Therefore, ATSDR is committed to evaluating their special interest at sites such as NSN, as part of the ATSDR Child Health Initiative.
ATSDR has attempted to identify populations of children in the vicinity of NSN and any completed exposure pathways to these children. As previously noted, approximately 6,700 children under the age of 6 live within 1 mile of NSN. There are no on-site childcare facilities, but the Camp Allen Elementary School is within NSN, directly southeast of Camp Allen Landfill Area B. Several other schools are located near the base.
ATSDR has evaluated the likelihood of children being exposed to contamination at NSN at levels of health concern. On the basis of available data, ATSDR has not identified site contamination that would pose a health hazard for children.
ATSDR has not identified any private wells used for drinking water near the site that draw from either the shallow or the deep aquifer that might be affected by groundwater contamination. ATSDR will evaluate new groundwater and drinking water data as they are made available to us.
Swimming in the Elizabeth River near shore is not recommended, and swimming in Willoughby Bay is thought to be uncommon, as the only nearby public beaches are located on the Chesapeake Bay. Because any exposures to surface water and sediment in the marine waters adjacent to the base would be limited, such exposures pose no apparent public health hazard to children. ATSDR evaluated child exposures to fish and shellfish harvested from Willoughby Bay. We reviewed available data on concentrations of contaminants present in fish and shellfish, available information on fish and shellfish consumption patterns, and toxicological literature about the potential for health effects from exposure to the contaminants detected. There has been no known harvest of oysters from Willoughby Bay since 1972, and past data reflecting contaminant concentrations in species other than oysters are limited. Furthermore, site-specific data about children's seafood consumption patterns is not available. However, available data indicate that temporary decreases in serum cortisol levels and short-term reversible gastrointestinal distress might have been possible in the past, if oysters with these levels of zinc were consumed. It should be stressed that these effects would have been short-term and reversible. ATSDR evaluated the potential for health effects to occur currently and in the future, based on the 2001 sampling results. Our evaluation concluded that current and future exposures to zinc from consuming fish and shellfish from Willoughby Bay would not be expected to cause any adverse health effects, since the only species that contained zinc levels sufficiently high to possibly cause these short-term, reversible health effects was the oyster, and oyster harvesting is not thought to occur. Appendix C provides a detailed explanation of ATSDR's evaluation process.
Children might occasionally come into contact with surface water and sediment contamination in drainage ditches that are affected by site-related contamination, such as the one south of the Camp Allen Elementary School. These drainage ways, however, are too small to permit swimming or fishing. ATSDR reviewed contaminant levels in drainage ditches where children might be exposed and concluded that these contaminants would not be expected to pose a public health hazard to children because of the limited exposures that would be anticipated. Children who live in on-base housing or who trespass on the base might access soil and debris at certain areas of the site. However, ATSDR did not find evidence that children are regularly accessing the sites under investigation within NSN. Children might have incidental contact with off-site soil, but the levels of contaminants detected in off-site samples are too low to cause adverse health effects in such situations. Therefore, soil contamination associated with NSN is not expected to pose a health hazard to children.
1. In Spring 2001, ATSDR had recommended (on the basis of the data then available) that VDEQ's summer 2001 biota samples include crabs, fish, clams, and oysters and that these samples be analyzed for organics and metals, including arsenic, thallium, and zinc. These new data have been incorporated into Table 6.
2. Cortisol is a hormone produced by the adrenal cortex that plays a role in regulating blood pressure, cardiovascular function, and the body's use of proteins, carbohydrates, and fats. Cortisol levels normally rise and fall during the day and are usually at their highest in the early morning and at their lowest around midnight. Cortisol is also produced in response to stress (either physical or psychological) to help the body deal with stressors, and cortisol levels may increase after meals (MEDLINEplus 2001; Stöppler n.d.).