PUBLIC HEALTH ASSESSMENT
BELTSVILLE AGRICULTURAL RESEARCH CENTER
BELTSVILLE, PRINCE GEORGE'S COUNTY, MARYLAND
The Beltsville Agricultural Research Center (BARC) is a large agricultural research complex operated by the Agricultural Research Service, a research agency of the U.S. Department of Agriculture. Research areas at BARC include natural resources, crops, livestock and poultry, and nutrition. The facility is located on about 6,600 acres in Beltsville, Maryland, in northwest Prince George's County. Adjacent to BARC are the cities of College Park and Greenbelt, Maryland. Washington, D.C. is about 5 miles away. Operations at the facility occur within five sections of the property: South Farm, North Farm, Linkage Farm, Central Farm, and East Farm. The facility is divided by the railroad right-of-way that bisects Linkage Farm into BARC-West and BARC-East.
Portions of BARC are enclosed by fences, but public access to BARC is possible via a number of public roadways that pass through the facility. Public access for recreational purposes to Central and North Farms is allowed at pre-determined times, but public access to BARC areas of concern (AOCs) is prohibited at all times. Approximately 36 privately-owned housing units, most of which are near Edmonston Road, are completely surrounded by BARC property. A few on-site housing units are owned by BARC and occupied by employees.
Contamination resulting from past activities at BARC is present at dump sites; chemical storage areas and burial sites; a burial site for material contaminated with low levels of radiation; and pesticide and herbicide mixing, application, and washdown areas. In 1994, BARC was added to the U.S. Environmental Protection Agency's National Priorities List because a former landfill, known as the Biodegradable Site, appeared to be contaminating nearby surface water in Indian Creek. Metals and semi-volatile organic compounds have been detected in groundwater, surface water, sediment, and soil at BARC; volatile organic compounds have been detected in groundwater, soil, and surface water; radionuclides and pesticides have been detected in groundwater, soil, and sediment; and polycylic aromatic hydrocarbons have been detected in soil and sediment. In addition, tetrachloroethylene (PCE) originating from the Beltsville Industrial Center is contaminating groundwater near Linkage Farm. The PCE plume results from the operation of a former dry cleaning supplier, W.P. Ballard & Company. Plans for W.P. Ballard to remediate the source of contamination are being developed.
The Agency for Toxic Substances and Disease Registry (ATSDR) prepared this public health assessment to evaluate past, current, and potential future exposures to contaminants originating at BARC. Based on two site visits, meetings with BARC representatives, information from site-related documents, and information provided by local government agencies, ATSDR identified and evaluated the following possible exposure pathways at BARC: groundwater, soil, surface water and sediment, fish, and physical hazards.
ATSDR concludes that the BARC water supply poses no apparent past, current public health hazard. The BARC water supply is not expected to pose a future public health hazard. Although various areas of groundwater contamination have been identified, BARC's water supplies are not contaminated at levels that would be expected to cause a public health hazard. BARC-West drinking water is provided by the Washington Suburban Sanitary Commission (WSSC); the water is drawn from rivers upstream of BARC and is treated according to state and federal regulations before being supplied to customers. BARC-East drinking water is provided by an on-site water supply system drawing groundwater from at least 150 feet below ground surface in the Patuxent Aquifer. This water supply system has been monitored since 1990, and measured constituents in the water it distributes have always met Safe Drinking Water Standards. Based on the locations and extent of site contamination and the fact that few removal actions have been conducted, ATSDR does not believe that levels of contamination in the Patuxent Aquifer would have been higher before 1990, when water supply monitoring began. ATSDR recommends that monitoring of the BARC water supply be increased, as a precautionary measure, to ensure the future safety of the water from migrating contamination. In addition, BARC production wells #9 and #10 should be sealed to prevent contaminant migration into the water distribution system, and production well #4 should be sampled for radiological parameters due to its proximity to a source of radiological contamination.
ATSDR considers past, current, and future exposure to drinking water from private wells in the immediate vicinity of BARC an indeterminate public health hazard based on the lack of information on private well use. Therefore, ATSDR recommends sampling private wells at residences within BARC's boundaries that might be in the path of future contaminant migration, as the extent of possible exposure and the potential for public health hazard is not fully defined. Areas in which utility pipelines intersect groundwater contamination should also be characterized. BARC and WSSC are coordinating to determine whether pipelines are located in affected areas. If there are any areas where small diameter water pipes (8" or less) pass through groundwater contamination, ATSDR recommends that taps served by such pipes be sampled.
ATSDR considers that off-site surface water and sediment exposure pathways, as well as fish consumption, pose an indeterminate public health hazard given the limited available sampling and exposure data. However, ATSDR also concluded that contamination could have migrated off site and affected surface water, sediment, and fish in Indian Creek. Contact with these media is prohibited within BARC. No environmental or use data from locations immediately downstream of BARC were available to evaluate potential off-site exposures. Additionally, the potential for contamination originating from sources other than BARC is not well defined. Therefore, the possibility for exposure to contaminants in off-site surface water, sediment, and fish is not fully defined and we recommend a use survey be conducted to determine whether appropriate sampling should be conducted.
Soil contamination at BARC does not pose a public health hazard, as it is limited to BARC areas of concern (AOCs) where public access is restricted. Any past or ongoing public exposure to the soil within contaminated areas would be expected to be infrequent, incidental, and of short duration. Adverse health effects are not expected to result from exposures to detected levels of contaminants at AOCs.
Physical hazards at BARC pose a possible hazard, as it may be possible for trespassers to encounter physical hazards that are not fenced or marked by signs, such as in-ground metal frames at ENTECH R5, within 200 feet of a playground. ATSDR recommends that BARC take all necessary measures to prevent access by the public, especially children, to AOCs containing physical hazards.
The Beltsville Agricultural Research Center (BARC) is the largest and most diversified agricultural research complex in the world. It is operated by the Agricultural Research Service (ARS), a research agency of the U.S. Department of Agriculture (USDA). The facility is located on about 6,600 acres in Beltsville, Maryland, in northwest Prince George's County. BARC property is not entirely contiguous, and most of its boundaries are convoluted. Most of the facility is east of Interstate 95, west of Telegraph Road, north of Interstate 495 and Maryland Route 193 (Greenbelt Road), and south of Sellman, Odell, and Powder Mill Roads. U.S. Route 1 and the Baltimore-Washington Parkway transect the property. Adjacent to BARC are Beltsville and the cities of College Park and Greenbelt, Maryland. Washington, D.C. is about 5 miles away. Figure 1 shows BARC's location and regional context.
BARC property is a mixture of fields, pastures, orchards, forests, animal facilities, and buildings. There are almost 800 structures on the property, ranging from office buildings, laboratories, and greenhouses to shops and barns (ENTECH 1999a). There are four on-site research programs: the Plant Science Institute, the Livestock and Poultry Science Institute, the Natural Resources Institute, and the Beltsville Nutrition Research Center. Operations at the facility occur within five sections of the property: South Farm, North Farm, Linkage Farm, Central Farm, and East Farm. Figure 2 depicts South, North, and Linkage Farms and the sites under investigation within the three areas. Figure 3 depicts Central and East Farms and associated features.
Historically, the facility was divided into BARC-West, where most research was related to plants, and BARC-East, where most work was related to animals and related crop growth. The dividing line was the B&O Railroad right-of-way that still passes through the facility, bisecting Linkage Farm. This right of way is now owned by CSX Corporation, and part of it serves as track for the Washington Metropolitan Area Transit Authority (WMATA) Metrorail.
BARC originated as a 475-acre farm in Beltsville, purchased by USDA in 1910. At that time, the facility was named the Experiment Farm of the Dairy and Animal Husbandry Divisions. The Dairy Division used 190 acres of the property, and the remainder was used by the Animal Husbandry Division. The farm grew in size throughout the 1920s. In 1933, USDA purchased land on the west side of Baltimore Avenue which its Bureau of Plant Industry had started to use the previous year under a lease. During the 1930s, major development on the property occurred. The Civilian Conservation Corps occupied several camps on the grounds of the facility and performed extensive improvements to the site, including building bridges, roads, and parking areas, as well as installing sewer and water lines (Bernard Johnson Young 1996).
After it reached its peak size of 12,000 acres, portions of BARC were transferred to other federal agencies. In these areas, the U.S. Department of Interior's Patuxent Research Refuge, Goddard Space Flight Center, the U.S. Secret Service's J. J. Rowley Training Center, and other facilities were created (Bernard Johnson Young 1996). Various federal agencies have also been tenants at BARC, including the U.S. Environmental Protection Agency (EPA), the U.S. Food and Drug Administration (FDA), the Department of Defense, the Department of Justice, and National Aeronautics and Space Administration (NASA). Currently, the only remaining tenant agencies at BARC are NASA (occupying two parcels on East Farm), the Agricultural Marketing Service, and the University of Maryland (using land in the southeast corner of East Farm) (Schoppet 1999b). Research at Hayden Farm, a parcel used by the University of Maryland, focuses on agronomic crops, integrated pest management, and environmental protection. The area, also known as the Beltsville Facility of the Central Maryland Research and Education Center, serves as an assembly site for research activities and as a field laboratory for agronomy and entomology students (CMREC n.d.). The University of Maryland also conducts turf grass research within South Farm (Schoppet 1999e).
Contamination identified at BARC has resulted from the handling and disposal of chemicals, including pesticides and radioactive agents, used in research and other activities conducted at the facility. Sources of contamination include landfills and dump sites, chemical storage areas, chemical burial sites, a burial site for material contaminated with low levels of radiation, and pesticide and herbicide mixing, application, and washdown areas. When pesticides or herbicides are sprayed on the site, warning signs are posted nearby, in accordance with the Federal Insecticide, Fungicide, and Rodenticide Act (Schoppet 1999a).
BARC is also affected by a plume of groundwater contamination, containing tetrachloroethylene (PCE) and other chlorinated solvents, near its border with the Beltsville Industrial Center. The plume results from the off-site operation of a former commercial dry cleaning supplier, W.P. Ballard & Company, located less than 1 mile northwest of a BARC area of concern (AOC) referred to as BARC 6, the Biodegradable Site, in Linkage Farm. Efforts are underway to ensure that the Ballard facility will be remediated to eliminate the source of the contamination. It is not currently known how far the plume extends off the Ballard property (Mortensen Engineering 1996).
EPA Region III first identified the BARC facility as a potential hazardous waste site in January 1980. In February 1988, BARC was added to the Federal Facilities Docket, pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and the National Oil and Hazardous Substances Pollution Contingency Plan. Placement on the Docket required that a Preliminary Assessment/Site Investigation (PA/SI) be conducted. In May 1991, BARC's PA/SI Report was submitted to EPA. The PA/SI identified 44 potential AOCs. In February 1993, EPA's Environmental Photographic Interpretation Center (EPIC) analyzed historical aerial photographs of the site, taken from the 1930s through 1992, and identified another 48 potential AOCs.
In May 1993, EPA proposed BARC for inclusion on the National Priorities List (NPL) because a former landfill, known as the Biodegradable Site, was contaminating nearby surface water in Indian Creek (ENTECH 1999a). In May 1994, BARC was officially placed on the NPL. USDA-ARS entered into a Federal Facilities Agreement with EPA, effective April 1998, that requires investigative methods be used to determine the AOCs at which Remedial Investigation/Feasibility Studies should be conducted (FFA 1998).
An additional 74 potential AOCs were identified after BARC was placed on the NPL, bringing the total number of potential AOCs at BARC to 166. The CERCLA process calls for AOCs identified as potentially contaminated to be designated "further action" sites. Based on data review and personnel interviews, 59 of the 166 potential AOCs were designated further action sites (ENTECH 1999a). Under the Site Screening Process (SSP), a risk screening must be conducted for each further action site to determine whether it will be subject to a Remedial Investigation/Feasibility Study (RI/FS). Under the SSP, Human Health Risk Assessment reports are being drafted for 54 AOCs, a number of which have been designated no further action sites. RI/FSs are in progress or planned for the Biodegradable Site (BARC 6), the Chemical Disposal Pits (BARC 12), the Low-Level Radiation Burial Site (BARC 18), the College Park Landfill (BARC 22), and Beaverdam Road Landfill (BARC 27) (ENTECH 1999e, Franklin 2001).
In September 1995, the Agency for Toxic Substances and Disease Registry (ATSDR) conducted an initial site visit and met with BARC representatives, ARS community relations staff, EPA and state regulators. In March 1999, ATSDR conducted another site visit to obtain an update on current site conditions and the status of remedial actions, as well as to collect site-related documents and environmental data. During the visit, ATSDR again met with representatives of BARC and the ARS community relations office.
At the time of the 1990 U.S. Census, there were 21,843 persons in district 1 of northern Prince George's County, which is 18.3 square miles in area. The District held a total of 8,064 households, and 12.5% of the population was were under the age of 10. The majority (68%) of homes were owner-occupied. Northern Prince George's County District 10 is 17.7 square miles in area and was inhabited, in 1990, by 48,231 persons in 19,579 households. 48% of homes were owner-occupied and 14.2% of inhabitants were children under the age of 10. Both Districts were more than 70% white and about 18% black. In district 1, 8% of the population were over the age of 65; in district 10, 6% of the population were over the age of 65 (Census of Population and Housing 1990).
According to the 1990 U.S. Census, the population of Beltsville was 14,476, the population of Greenbelt was 21,096, and the population of the College Park, excluding the University of Maryland community, was 23,714. There are about 32,000 undergraduate and graduate students at the University of Maryland-College Park and about 8,000 staff (USDA-ARS-BARC 1996).
Currently, the number of BARC employees ranges from 1,450 to 3,000, with the variation due to the large numbers of seasonal workers, interns, visiting researchers, and other temporary staff (Schoppet 1999a). It is estimated that about 5,000 employees worked at the facility in the mid-1950s. The National Agricultural Library, located within the confines of BARC, was built in 1968. As of 1996, it employed about 150 people (Bernard Johnson Young 1996). In 1998, a USDA Office Complex, with 1,500 employees, opened within the confines of the Beltsville Area. However, the land upon which the Office Complex was built has officially been transferred to USDA. This complex is not formally a part of BARC. There are also about 10 individuals who work in the Agricultural Marketing Service's on-site offices (Schoppet 1999c).
BARC land is shielded from development by both state and federal law. Maryland law designates BARC property as "agricultural open space" and prohibits the Prince George's County Council from changing that designation (Pierre 1993). In addition, Congressional approval is required before any BARC property is sold or transferred.
Much of the land use surrounding the facility is residential, commercial, or transportation-related. The Washington Metropolitan Area Transit Authority (WMATA) Storage and Inspection Yard is located along the eastern edge of Linkage Farm. Most commercial development is near the U.S. Route 1 corridor and north of Sunnyside Avenue, in the Beltsville Industrial Center. Residential developments associated with Beltsville, College Park, and Greenbelt are located along the western, southwestern, and, to a lesser extent, northwestern perimeters of BARC. A federal courthouse is outside the southwestern boundary of the facility. Around the northeastern, eastern, and southeastern boundaries of BARC are other federal facilities, such as the Patuxent Research Refuge; the National Plant Materials Center, operated by USDA's Natural Resource Conservation Service; the U.S. Army's Fort George G. Meade Military Installation; and NASA's Goddard Space Flight Center (ENTECH 1999a; Bernard Johnson Young 1996). Certain areas along the northwestern and southwestern boundaries of BARC, especially those along creeks, are publicly-owned. Many are made available to the public by the Maryland-National Capital Park and Planning Commission (M-NCPPC) for recreational use.
Although portions of BARC are enclosed by fences, public access is possible as a number of public roadways pass through the facility. Limited public access to the facility is allowed pursuant to federal regulations that permit pedestrians, pets on leashes, bicycles, and photographers. Prohibited, among other things, are fishing, camping, horseback riding, nuisances, and damaging or removing BARC property (7 CFR Part 502 1999). Currently, BARC allows access only to Central Farm and North Farm on Sundays from 6:30 a.m. until dusk and Monday through Friday from 6:30 a.m. until 3:30 p.m. (Real Property Section n.d.). Warning signs are posted in various locations throughout the facility advising individuals that unauthorized use of BARC grounds is prohibited (BARC 1999).
Formerly, individuals requesting permission to access the site for recreation were issued a USDA-ARS Revocable Permit and an information packet. The information packet contained a map and fact sheets for the facility and its AOCs and made clear that the public is forbidden to access research and foliage fields, restricted areas, roads closed by gates or posted closed, and AOCs under investigation by the facility (Real Property Section n.d.). Approximately 50 to 75 permits were issued per year for the roughly 10-year period they were used (Bynum 1999). In April 1999, BARC stopped requiring recreational users of the facility to hold a permit. BARC now gives information packets to individuals who inquire about using the site for recreation. The Real Property Section does not maintain records of the names and addresses of those individuals (Bynum 1999).
To control the deer population at BARC, a wildlife management plan for the facility was implemented in 1995. The plan allows the public to hunt deer in 25 designated areas of BARC east of the Baltimore-Washington Parkway--none of them near residences or other buildings--from October through January. None of the designated areas is open to the public for any other type of use. Members of the public wishing to participate in the hunt must apply to BARC and must possess a hunting license, must have completed a hunting safety course, and must pass a proficiency test administered by BARC. Public hunts have occurred annually since 1995, but employee hunts have been ongoing for longer. Current wildlife management policies also allow selected BARC employees to hunt deer in designated areas west of the Baltimore-Washington Parkway. These individuals also must pass safety and proficiency tests and are advised how many deer to take (USDA-ARS-BARC 1995a, b, and c).
There are currently approximately 36 privately-owned housing units completely surrounded by BARC property (known as "residential inholdings"), all of them located within BARC-East. One residence is located on the eastern side of Central Farm, off Powder Mill Road and east of Bicontrol Road, not far from the Baltimore-Washington Parkway. Two residences are located in East Farm, on adjacent lots. These lots are just north of Beaver Dam Road and just east of the Baltimore-Washington Parkway (McGuire 1999). The remainder of the residential inholdings are close to Edmonston Road, the boundary between Linkage and Central Farms. Specifically, residences are located on Edmonston Road near its intersection with Beaver Dam Road, on Rosedale Lane, and on Beaver Dam Road in the vicinity of Rosedale Lane (BARC 1999).
An estimated 18 on-site housing units are owned by BARC (Bernard Johnson Young 1996). BARC employees previously lived in some or all of these residences. Some of these employees reportedly raised families in these residences (McGuire 1999). Currently, only three or four of the housing units are occupied, and it is not expected that a larger number of BARC-owned residences will be occupied in the future (Schoppet 1999a; McGuire 1999). Reportedly, children are currently living in one of the occupied residences (McGuire 1999). There are no schools, elderly housing units, or hospitals at BARC. There are no playgrounds on BARC itself, but Sunnyside Neighborhood Playground is adjacent to BARC, about 300 feet south of an AOC in Linkage Farm known as ENTECH R5.
An on-site daycare center, run by the employees' association, serves 21 children (Schoppet 1999a). The center has operated in a remodeled house in North Farm since the late 1970s (Schoppet 1999d). While the center is located near an AOC (EPIC 11, an area formerly known as the Atomic Energy Greenhouse), children do not play outside the center's fenced playground, as required by the center's license (BARC 1999; Schoppet 1999c). A childcare facility is also slated to open at the USDA Office Complex, not far from BARC 6 (BARC 1999).
Located within Central Farm is the College Park Landfill, operated by the city of College Park until 1978. After the landfill closed, four baseball/softball diamonds were created on the site. Use of two of these fields was discontinued after the summer of 1997 (Schoppet 1999a).
BARC lies within the Atlantic Coastal Plain Province, in an area of rolling terrain with broad valleys. Elevations within the facility range from about 60 feet above mean sea level (msl) to about 265 feet above msl. In general, higher elevations and steeper slopes occur in the northern and western parts of BARC, in North and South Farms. Agricultural fields are prevalent in western areas, while wooded tracts predominate in the central and eastern portions of the facility (Bernard Johnson Young 1996; ENTECH 1997c).
There are a number of streams, wetlands, and surface water bodies within BARC, many of which are located in the southern and western parts of the facility. Figure 4 depicts the major surface water features on the site. The largest streams flowing through BARC property are Beaver Dam Creek, Indian Creek, Little Paint Branch, and Paint Branch. Beaver Dam Creek flows westward from East Farm through Central Farm; it joins Indian Creek, a southward flowing stream, on the west side of Edmonston Road, just inside Linkage Farm. Little Paint Branch flows southward through North Farm, and Paint Branch runs southeast through South Farm. Little Paint Branch joins Paint Branch approximately 1,000 feet from the southeast corner of South Farm. All of the streams eventually feed the Anacostia River, which empties into the Potomac River. All surface water bodies within BARC have been designated by the Maryland Department of the Environment (MDE) as subject to water quality standards appropriate for "Use I"--suitable for fishing, water sports, supplying water for agricultural and industrial uses, and supporting most types of aquatic life and wildlife (Galli 1999; MDE 1999b).
On-site wetlands are common near most of the surface water drainages within BARC. There is a small man-made ornamental pond outside the National Agricultural Library that is the home to ducks and other wildlife during certain portions of the year. There is a large pond in the southeastern portion of the site, near Goddard Space Flight Center, which was probably created by damming Beck Brook, a tributary of Beaver Dam Creek (ENTECH 1997c). While BARC has two wastewater treatment plants , operating under National Pollutant Discharge Elimination System (NPDES) permits, the facility does not manage storm water runoff (Schoppet 1999b).
Use of the water bodies within BARC property for fishing, swimming, or other recreational activities is prohibited (Bynum 1999). No evidence exists that any members of the public are trespassing on the site to access the creeks. In many areas, access is further impeded by dense underbrush (BARC 1999). There is, however, recreational use of the creeks off-site on parcels managed by the M-NCPPC (M-NCPPC n.d.).
M-NCPPC owns land along Little Paint Branch immediately downstream of BARC's North Farm, known as Cherry Hill Road Community Park. A Hiker/Biker/Equestrian (H/B/E) Trail known as Paint Branch Trail, constructed in approximately 1997, begins at this park and runs along Little Paint Branch (Nivera 1999). M-NCPPC also owns land adjacent to Little Paint Branch north of North Farm, off Sellman Road. This area, known as Little Paint Branch Park, hosts the Beltsville Community Center and associated facilities, including an exercise trail. M-NCPPC is considering a future arrangement with BARC to link Cherry Hill Road Community Park and Little Paint Branch Park with a trail running through existing roads in North Farm (Nivera 1999). M-NCPPC regulations state that boating is not allowed on its property except by permit, swimming is allowed only in areas designated for such use, and recreational fishing is allowed in designated areas in compliance with Maryland State Angler's license requirements (M-NCPPC 1987).
According to the Mounted Unit of the Maryland-National Capital Park Police, which patrols M-NCPPC parks, boating does not occur near the Paint Branch Trail because there is not sufficient stream flow. In addition, the water is mostly too shallow for swimming, and any swimmers spotted in the water by officers are asked to leave the water. Wading is allowed and occasionally occurs, often in conjunction with recreational fishing (Vasco 1999).
Little Paint Branch and Paint Branch contain game fish, including brown trout, in the vicinity of BARC. Indian Creek does not support appreciable fish populations, and although Beaver Dam Creek does, it does not contain the kinds of fish that would make it attractive to anglers (Galli 1999; 2000). See Figure 4 for the locations of these streams. Also, the area within a mile downstream of the confluence of Beaver Dam and Indian Creeks is difficult to access (Galli 1999; Nivera 1999). Some recreational fishing reportedly occurs in old washponds located near BARC, but these ponds do not support edible fish (Finch 1999).
Along the eastern edge of Indian Creek, south of Greenbelt Road and over a mile southwest of where Indian Creek leaves BARC property, is an M-NCPPC park known as Indian Creek Park and a H/B/E trail known as Indian Creek Trail. Although inconsistent with M-NCPPC rules, it has been reported that children sometimes swim in Indian Creek near Berwyn Heights Neighborhood Playground (Nivera 1999). This area is over a mile and a half from the point at which Indian Creek leaves BARC property.
The land along Indian Creek between the Capital Beltway and Greenbelt Road is owned by WMATA. Part of the property has been developed into the Greenbelt Metrorail Station and its associated parking lots and service areas. The southern portion of the WMATA property is not yet developed. In this area, the channel of Indian Creek is shallow and braided and hosts many rare species; any future development will be planned in a manner to protect these species. It is possible that the Indian Creek Trail may be extended north of Greenbelt Road to allow public access to the area. A trail connecting the USDA Office Complex to the Greenbelt Metrorail Station was proposed by USDA; whether or not such a trail is built will depend, in part, on CSX Corporation's plans for its property (Nivera 1999).
In preparing this public health assessment, ATSDR reviewed and evaluated information provided in the referenced documents. Documents prepared for the CERCLA and Resource Conservation and Recovery Act programs 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 document are from BARC reports, including investigations of AOCs, as well as from information provided by MDE about the Ballard site and about fish sampling downgradient of BARC. Based on our evaluation, ATSDR determined that the quality of environmental data available in site-related documents is adequate to make public health decisions.
In this section, ATSDR evaluates environmental information to determine whether contamination poses hazards to people having access to or living near the BARC facility. ATSDR's public health assessments are driven by exposure to (contact with) contaminated media. In evaluating exposure pathways, ATSDR determines whether exposure to contaminated media has occurred, is occurring, or will occur through ingestion, dermal (skin) contact, or inhalation of contaminants. When exposure to contaminated media occurs, the exposure pathway is regarded as "complete." To determine whether completed pathways pose a potential health hazard, ATSDR compares contaminant concentrations to health-based comparison values (CVs). CVs are calculated by ATSDR toxicologists, using available scientific literature on exposure and health effects. These values, which are derived for each of the different media, reflect the estimated contaminant concentration for a given chemical that is not expected to cause health effects, given a standard daily ingestion rate and standard body weight for specified periods of time. Contaminants detected above the CVs do not automatically present a public health hazard. If contaminant concentrations are above CVs, ATSDR further analyzes exposure and the toxicology of the contaminant to determine whether a public health hazard could occur. See Figure 5 for a depiction of ATSDR's exposure evaluation process.
ATSDR reviewed available data from environmental monitoring at BARC. Table 1 presents ATSDR's site-by-site evaluation of BARC AOCs at which sampling data have been collected. Table 2 presents a description of AOCs at which no samples have been collected to date, but sampling is planned. ATSDR identified and evaluated the following possible exposure pathways at BARC: groundwater; soil; surface water and sediment; fish; and physical hazards. The following sections present an evaluation of potential exposure pathways, which are also summarized in Table 3. To acquaint readers with terminology and methods used in this report, Appendix A provides a glossary of terms and Appendix B describes ATSDR's comparison values.
The BARC site is underlain by formations primarily from the Lower Cretaceous Period. These unconsolidated Lower Cretaceous sediments have been identified as the Potomac Group. From older to younger, the Potomac Group consists of the Patuxent, Arundel, and Patapsco Formations. Geologic maps indicate that the Patuxent Formation (the deepest of the three) and the Arundel Formation underlie BARC, whereas the Patapsco Formation may only be present in the eastern reaches of the BARC facility (ENTECH 2000a). The Patuxent and Patapsco Formations are predominantly sand and gravel materials and contain groundwater, while the intervening Arundel Formation is predominantly clay. The formations dip to the southeast, the general direction of regional groundwater flow.
The Patuxent Formation outcrops in the western portion of BARC, approximately as far east as Edmonston Road (the eastern boundary of Linkage Farm). Investigations around BARC 6 reveal that the Patuxent outcrop extends through the BARC 6 site. Geologic and lithologic data collected during the RI indicate that the BARC 6 site is underlain by approximately 10 to 20 feet of alluvial materials and approximately 120 feet of the Patuxent Formation. The alluvium occurs in a narrow area along Indian Creek. In the central portion of BARC, the Patuxent Formation is overlain by the Arundel Formation. In the eastern portion of BARC, these two formations may be overlain by the Patapsco Formation. Where it overlies the Patuxent Formation, the Arundel Formation minimizes vertical migration of groundwater from the Patapsco Aquifer to the Patuxent Aquifer. Generally speaking, water in the deeper Patuxent aquifer is separated from water in the shallow Patapsco aquifer by the intervening Arundel Formation. However, in the vicinity of the BARC 6 site, the barrier created by the Arundel Formation is not present, as the site sits directly on top of alluvial fill material and the Patuxent Formation outcrop. The Patapsco Aquifer is recharged by the infiltration of precipitation. The Patuxent Aquifer is recharged by water moving through outcrops such as those in the western portion of BARC (ENTECH 1997c).
Hydraulically, the alluvium and underlying Patuxent Formation are interconnected. The BARC 6 site is located in an area of groundwater discharge, and there are wetlands east of the site. This condition may help prevent groundwater contamination from moving further downgradient or off site of the BARC property. Localized groundwater flow direction around the BARC 6 site was determined to be southeasterly, and flow velocity within the Patuxent Formation was determined to be on the order of 20 to 120 feet per year (ENTECH 2000a).
All water used on BARC-East currently and in the past has been provided by the BARC water distribution system (Brabon 1999a; McGuire 1999). The first BARC production well was apparently completed in 1911. More wells were drilled in Central and East Farms over time. According to well completion reports submitted for BARC wells, as compiled by the state of Maryland, all BARC wells were screened in the Patuxent Aquifer and were designed to draw groundwater from at least 150 feet below ground surface (Maryland Geological Survey 1983). Most of these wells were drawing from the portion of the Patuxent Aquifer underlying the Arundel Formation, which may serve as a confining layer where it exists (Brabon 1999a).
From 1910 through the mid-1940s, four separate water systems evolved on BARC-East, each centered around a water tower (Brabon 1999a). In the late 1940s, however, a new water distribution system was completed. The system drew water from up to 11 BARC production wells and piped the water to a new BARC water treatment plant, serving as a core distribution center (Cassell 1999a; Brabon 1999a). Over time, production wells used to supply the BARC-East water system were replaced or redrilled. BARC's most recent water system assessment and rehabilitation project lasted from 1996 to 1999. The project resulted in drilling one new well (#1) and redrilling three old wells (#5, #6, and #7). Each of these wells has received or will receive a Certificate of Potability (COP) from the state of Maryland. After COPs are obtained, the wells will be put into service. Older wells do not require such certification (Cassell 1999a; Brabon 1999a).
Figure 6 shows the locations of the BARC-East water supply wells. Wells #2, #3, and #4 have been active since the mid-1970s or earlier. Well #1 is a new well, installed in 1997, that has only been operating for the last few years. The former well #1, less than 0.5 miles west of new well #1, was taken out of service in the 1970s. Well #6, also redrilled in 1997, has received its COP and is back in use. Wells #5 and #7, redrilled in 1999, have only been operating since that time. Wells #8 and #11 are secondary wells, operated only intermittently. Wells #9 and #10, in the Animal Parasitology Unit (APU), were taken out of service prior to 1993 and are not expected to be redrilled at this time (BARC Information Repository 1993; Cassell 1999a). The water system is designed so that, at any given time, at least three wells are used to supply water to the treatment plant. In the future, the system may rely solely on well #1 in the event of a power failure because it is the most recently installed well, has a suitable yield, and is adjacent to monitoring and treatment infrastructure (Brabon 1999a).
As explained above, on-site groundwater is treated at the BARC water treatment plant before being distributed to BARC-East. The plant has been upgraded periodically to incorporate new treatment technologies. According to the operator of the water treatment plant, the average daily use of water from the plant ranges from about 350,000 to 650,000 gallons of water. After the water is treated, it is regularly tested at the plant to ensure that it meets all applicable drinking water quality standards (BARC 1999).
In general, water testing is performed according to a sampling schedule set by MDE. Until recently, the BARC water system was designated a Community Water Supply, a designation that applies to water systems serving 25 or more year-round residents. In May 1998, MDE changed the designation of the water system to a Non-Transient/Non-Community Water Supply, defined as a system that serves more than 25 people for 6 or more months per year, such as a workplace (Poreda, 1999). The sampling schedule set by MDE for BARC's water supply is based on the assumption that the water is drawn from a confined aquifer (Poreda, 1999). MDE currently requires BARC to sample drinking water according to the following schedule:
- test iron levels in the plant effluent every week;
- draw four bacteriological samples each month;
- monitor concentrations of arsenic, fluoride, and metals every 3 years;
- measure gross alpha levels every 4 years;
- test levels of volatile organic compounds (VOCs) every 6 years;
- monitor levels of nitrate annually;
- no nitrite samples have been required since sampling for nitrite in 1993, and
- no additional rounds of sampling for synthetic organic compounds are required.
(Cassell 1999a; Seekins 1999; Poreda, 1999)
The Washington Suburban Sanitary Commission (WSSC), a water and sewer agency established for Montgomery and Prince George's Counties in 1918, provides water to BARC-West (WSSC n.d.a.; BARC 1999). It is believed that WSSC has provided water to the buildings on BARC-West since they were first built (McGuire 1999). Wastewater created on BARC-West, like that created on BARC-East, is managed by the facility itself. For irrigating fields, BARC-West also uses surface water from Little Paint Branch, within the limits of two permits issued by the state of Maryland's Department of Natural Resources (Cassell 1999a).
Drinking water for most of Prince George's County and neighboring areas is currently provided by WSSC. WSSC draws water from the Patuxent and Potomac Rivers. The Potomac River intake is greater than 15 miles upstream of BARC (Laufer 1999; Schoppet 1999e). Water from the Patuxent River is pumped from the T. Howard Duckett reservoir, north (upstream) of BARC. Before being provided to customers, water collected is treated at either the Patuxent or the Potomac water filtration plants. Customers in Beltsville, College Park, and Greenbelt receive a blend of water processed at both the Patuxent and Potomac Water Filtration Plants (WSSC n.d.b.).
Research associated with BARC's SSP, conducted by a BARC contractor, suggested that there might be off-site private drinking water wells serving certain residences north of Central and East Farms (ENTECH 1999a), but this information has not been confirmed. There is no documentation to verify the extent to which people might have relied upon wells in the past. WSSC water is currently available to the private residences located within BARC near Edmonston Road; no private wells are in use in that area (BARC 1999; Wise 1999). However, the three other residential inholdings within BARC have private wells (McGuire 1999).
Nature and Extent of Groundwater Contamination
Shallow groundwater contamination is associated with some of the AOCs at BARC. (See Table 1 for detailed information.) Based on sampling to date, the most notable groundwater contamination appears to be associated with BARC 6, BARC 12, BARC 18, and BARC 22. In addition, BARC is affected by a plume of chlorinated VOC contamination from the adjacent Ballard CERCLA site. Radionuclides have been detected at BARC 41 and EPIC 11, but the extent of radiological contamination near these two sites has not yet been determined.
BARC 6, known as the Biodegradable Site, is a former landfill east of Edmonston Road, within Linkage Farm. The site is located in the eastern portion of Linkage Farm, where the Patuxent Formation outcrops. About 10 to 20 feet of alluvial materials overlie the Patuxent Formation at the site. Groundwater flow at the site is to the southeast and shallow groundwater is thought to discharge to Indian Creek. VOCs and metals have consistently been found above CVs in shallow and deep groundwater (ENTECH 1998b, c, h, 1999b). In addition to contaminants attributed to the BARC 6 site, the site is also affected by a plume of contaminated groundwater originating from the upgradient Ballard site. The Ballard plume consists primarily of PCE and its breakdown products, including trichloroethylene (TCE). Samples from BARC 6 collected at depths of 40 to 90 feet contained higher levels of chlorinated VOCs and lower levels of metals than samples collected from shallow depths. In 1998, Geoprobe® sampling indicated that groundwater contamination, including contaminants from BARC 6, was still some distance from the nearest BARC production well. This well, located approximately 3/4 of a mile southeast of BARC 6, is not currently in service and not expected to be put back into service (ENTECH 1998c,h, 2000).
The W.P. Ballard & Company hazardous waste site is located in the Beltsville Industrial Center, which is adjacent to Linkage Farm, north of Sunnyside Avenue and west of the B&O Railroad right-of-way. W.P. Ballard was a former dry-cleaning supplier that operated from 1965 to 1988. PCE was stored and distributed at the site, and, in 1988, there was a release of several hundred gallons of PCE from an aboveground storage tank. PCE has been found at high concentrations in shallow groundwater under the site. TCE and dichloroethylene (DCE), which are breakdown products of PCE (ATSDR 1997), have also been found. The site sits atop the Patuxent Formation outcrop; groundwater flow is to the southeast (Mortensen Engineering 1996). In 1997 samples from groundwater monitoring wells located on the Ballard site, concentrations of PCE reached 140,000 micrograms per liter (µg/L); in off-site samples, concentrations reached 47,000 µg/L (Mortensen Environmental 1997). The extent of off-site contamination has not been fully characterized, and the schedule for characterization, remediation, and source removal is uncertain. Concentrations of chlorinated solvents in downgradient groundwater are expected to increase until the source has been removed.
Groundwater contaminants entering the Patuxent Formation, such as PCE, TCE, and other chlorinated compounds, may serve as persistent sources of downgradient plumes of contaminated groundwater. When these compounds are released in their pure form, dense non-aqueous phase liquids (DNAPLs) are formed. DNAPL contaminants are heavier than water and sink to the bottom of aquifers or permeable formations, settling into a pool at a low point or on top of a clay or bedrock formation. DNAPLs exist in a separate phrase from groundwater and slowly dissolve into it. DNAPL pools, if not removed, will serve as sources for persistent groundwater contamination. At the BARC site, the bottom of the Patuxent Formation is nearly 130 feet below ground surface. Given the tendency for chlorinated compounds to sink, it is important to analyze groundwater samples from the bottom of the formation in this area.
BARC 12 is a site formerly used for surface dumping and burning, as well as chemical disposal. The site is located in the northeast portion of Central Farm, near an unnamed stream that lies just off of BARC property. The Arundel Clay Formation underlies the site; some fill materials and sand are found above this formation (ENTECH 1998g). Shallow groundwater flows northeast toward the stream (ENTECH 1998b). VOCs, metals, and pesticides have been found above CVs in shallow groundwater (ENTECH 1998b,g). No BARC production wells are located east of the AOC. Furthermore, the layer of Arundel Clay acts as a hydraulic barrier above the Patuxent Formation.
BARC 18 is a site at BARC-West where low-level radioactive waste was buried. The Patuxent Formation is at the surface at the site. A plume of contamination is migrating southeast from the site in the Patuxent Aquifer. Principal plume contaminants are low levels of chloroform, tritium, Ra226 and Ra228, and C14. December 1998 sampling indicated that the plume had not left BARC property (ENTECH 1999d). The site is in the western portion of BARC-West and there are no BARC production wells in the vicinity.
BARC 22 is a former municipal solid waste landfill also known as the College Park Landfill, located in Central Farm, near its border with Linkage Farm. Beaver Dam Creek flows along the southern perimeter of the AOC. BARC 22 is situated overtop of the Arundel Formation, just east of the edge of the outcropping of the Patuxent Formation. Geologic layers underlying the landfill are fill materials, followed by sand and gravel, followed by clay. VOCs, semi-volatile organic compounds (SVOCs), and some metals were found above CVs in shallow groundwater in the vicinity of the landfill. However, the clay layer is believed to act as a natural liner for the landfill, limiting the downward migration of shallow groundwater. Former BARC production wells located southeast of the site are not thought to have been impacted by groundwater contamination coming from BARC 22 (ENTECH 1998g, 1999e).
BARC 41 contains a building, B-312, that housed boxes and drums marked with radiation warning labels. Sampling was conducted at the AOC in late 1998 and early 1999. Five groundwater samples were analyzed for gross alpha, non-volatile beta, and several radionuclides, which were detected at concentrations exceeding screening values. BARC production well #4 is 25 to 50 feet northeast of B-312 and has not been sampled for radiological parameters.
EPIC 11 was used by the Atomic Energy Commission to investigate the effects of small quantities of radioactive contamination on plants in the 1950s and 1960s. In 1999, three groundwater samples were analyzed for selected radiological parameters. Radium-226 and gross alpha levels exceeded screening values. The site is in North Farm, and there are no BARC production wells in the area.
Sampling of the BARC water supply to date has resulted in only sporadic, low-level detections of contaminants. In 1994, production well #6 was tested for pesticides by MDE; none were detected (BARC Information Repository 1995a). In July 1998, in connection with applying for a COP, a full round of sampling was performed at the redrilled well #6, and all parameters analyzed were within regulatory limits. Subsequently, new well #1 underwent the same tests. 1,2-Dichloropropane was detected at 7.8 µg/L, slightly exceeding the EPA's Maximum Contaminant Level (MCL) for drinking water (5 µg/L). Before bringing well #1 online, BARC will submit a plan to MDE to ensure that levels of the compound in the water distributed by the plant are always below the MCL (Brabon 1999a).
Information provided to ATSDR by BARC and MDE indicates that sampling of the water distributed by BARC for hazardous constituents began in 1990. From 1990 to 1996, the BARC water treatment plant influent was sampled three times for metals, three times for VOCs, twice for nitrate/nitrite, and once for radon. Plant effluent was sampled once for radon and once for gross alpha (BARC Information Repository 1995a,b; Poreda, 1999). According to MDE records, all samples of water distributed by the BARC water treatment plant met Safe Drinking Water Act standards (Seekins 1999; BARC Information Repository 1995a,b).
BARC sampled all its production wells (except #9 and #10, which are closed) for VOCs, SVOCs, pesticides, polychorinated biphenyls (PCBs), and metals during the summer and fall of 1999 (Brabon 1999b). At the same time, it also analyzed samples from its water supply plant before treatment, after aeration, and after filtration. No SVOCs, pesticides, or PCBs were detected in any of the samples. Several metals and VOCs were detected at levels below health concern in individual wells, but the only contaminants detected at concentrations exceeding MCLs were lead (74.2 µg/L in well #5), TCE (6.4 µg/L in well #5), and 1,2-dichloropropane (8.96 µg/L in well #1). No VOCs or metals were detected in water treatment plant samples at levels of health concern, and all parameters were within regulatory limits (ENTECH 2001a, b).
Sampling conducted to date does not indicate that groundwater contamination originating from BARC has migrated off of BARC property. However, samples have not been collected from all potentially-affected areas (including at the residential inholdings within the BARC perimeter using private wells). Therefore, further sampling is recommended at some sites. See Table 1 for additional details.
Evaluation of Potential Public Health Hazards
Water distributed to BARC-West by WSSC is sampled regularly according to the requirements of the Safe Drinking Water Act. Since the inception of the BARC water supply system in the late 1940s, the drinking water it supplies to BARC-East has been treated according to applicable standards of the day. Since 1990, the BARC water supply has been sampled at regular intervals for contaminants. This sampling has revealed very low levels of organic contaminants in some BARC production wells. Lead was also detected in a 1999 sample from one well. However, water from all production wells is mixed and treated at the BARC water treatment plant before being distributed, and samples from the plant have not contained any contaminants at concentrations of health concern. Based on the locations and extent of site contamination and the fact that few removal actions have been conducted, ATSDR believes that past levels of contamination in the Patuxent Aquifer would have been similar to levels detected since 1990, when water supply monitoring began. Thus, ATSDR concludes that the BARC water supply poses no apparent past, current, or future public health hazards.
Contaminants originating from the Ballard site, BARC 6, and other BARC AOCs, as well as surface contamination located in the area where the Patuxent Aquifer outcrops, can impact groundwater quality in the Patuxent Aquifer, from which the BARC water supply system draws. Because of the potential for contaminant migration, ATSDR recommends increased monitoring of the BARC-East water supply system for parameters identified at BARC AOCs and the Ballard site.
According to information received from the foreman of the BARC water plant, production wells #9 and #10 were not properly sealed after their use was discontinued (Brabon 2000). In order to eliminate the possibility of contamination from the vicinity of these two wells reaching the BARC water supply, ATSDR recommends that the wells be properly sealed. ATSDR further recommends that production well #4, which is located less than 50 feet from a source of radiological contamination, be tested for radiological parameters.
Shallow wells potentially downgradient of groundwater contamination, on private property inside and surrounding BARC may have been used as a source of drinking water in the past. Data about the use of these wells are incomplete and information on the extent to which they may have been contaminated is unavailable. Although WSSC water is now available in most areas near BARC, a small number of wells may be in use near BARC and at residential inholdings within BARC. Information about these potential wells is also incomplete (Wise 1999; Brabon 1999b; McGuire 1999). A resident living off Sunnyside Avenue, adjacent to the new USDA Office Complex, reported relying upon well water in 1993. This well was tested in March 1993 and all parameters except thallium were below regulatory standards. Thallium, which exceeded the regulatory standard only slightly, is not thought to be associated with BARC activities and may be naturally occurring (Roe 1993).
Based on the lack of information on private well use, ATSDR considers past, current, and future exposure to drinking water from private wells in the immediate vicinity of BARC an indeterminate public health hazard. ATSDR recommends that BARC sample private wells at the three residential inholdings located near the Baltimore-Washington Parkway. If the ongoing groundwater characterization efforts suggest that groundwater contamination might reach any of the other residential inholdings or any off-site private residences, ATSDR recommends that a comprehensive survey of private well use be performed and that any potentially affected wells be sampled.
Nature and Extent of Contamination
Various areas of surface and subsurface soil contamination have been found at BARC AOCs that have undergone sampling. (See Table 1 for detailed site-by-site information.) Soil samples have not yet been collected at numerous other AOCs, described in Table 2. Contaminants measured in surface and/or subsurface soils above CVs include PCBs, polycyclic aromatic hydrocarbons (PAHs), pesticides, and metals. Levels of VOCs and SVOCs exceeding CVs have only been detected in the subsurface soil samples collected from former disposal areas.
Evaluation of Potential Public Health Hazards
The public is not currently allowed to access any BARC AOCs, and much of the soil contamination is located in subsurface soil that is inaccessible. Remediation plans indicate that BARC will conduct appropriate remedial actions at AOCs to prevent public exposure in the future. Information collected to date indicates that any public exposure to the soil within contaminated areas has been or would be infrequent, incidental, and of short duration. ATSDR does not expect that exposures to the levels of contaminants found and expected to be found would cause adverse health effects. Thus, soil contamination at BARC poses no apparent past, current, or future public health hazard. ATSDR will evaluate any additional sampling data that becomes available as it is submitted to us.
Nature and Extent of Contamination
Surface water and sediment sampling has been conducted at certain BARC AOCs. (Refer to Table 1 for a summary of each site with existing data and Table 2 for information about sites where sampling is planned. Refer to Figure 4 for locations of surface water.) Since many investigations are pending, complete information about the extent to which the facility has impacted surface water and sediment is unavailable. Findings to date are summarized below. 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 CVs are used as a conservative screening method and assume long-term daily exposure. For recreational uses of streams, exposure is expected to occur significantly less frequently than assumed by the CVs. Moreover, the surface water bodies in question are not used for drinking water.
The only off-site surface water or sediment samples are surface water samples collected by MDE in the Northeast Branch of the Anacostia River, into which Paint Branch, Little Paint Branch, Indian Creek, and Beaver Dam Creek flow. The nearest downstream sampling location utilized by MDE is more than 4 stream miles below BARC, just south of East West Highway (Forrest 2000). Surface water samples collected so far downstream of BARC would not provide any information about BARC-related contamination.
Paint Branch and Little Paint Branch Watershed
The only surface water and sediment samples collected in portions of BARC that drain to Paint Branch or Little Paint Branch were associated with BARC 18, the Low-Level Radiation Burial Site, although sampling activities at other AOCs are pending. In 1997, four surface water and sediment samples from locations downgradient of BARC 18 were analyzed. Two of the samples were collected from a tributary to Little Paint Branch, and two were collected from drainage ditches in research fields. None of the samples contained evidence of site-related contaminants (ENTECH 1999d).
Indian Creek and Beaver Dam Creek Watershed
Sediment and surface water samples collected from Indian Creek contained metals and VOCs at levels exceeding CVs. Some of this contamination is attributable to an off-site source, the W.P. Ballard & Company site, being addressed under Maryland's Voluntary Cleanup Program. Twenty surface water samples have been collected between 1992 and the present and analyzed for VOCs in connection with investigations of the Ballard site. A number of the samples in which VOCs were detected were collected from within BARC property, north of Sunnyside Avenue. In three 1992 samples, the concentration of PCE reached only 12 µg/L. However, in four June 1993 samples, PCE levels reached 46,000 µg/L. TCE (reaching 120 µg/L), 1,1,1,2-tetrachloroethane (reaching 64 µg/L), and vinyl chloride (reaching 77 µg/L) were also detected in the June 1993 samples. In one August 1993 sample, PCE (1,535 µg/L), chloroform (5.1 µg/L), TCE (29 µg/L), and methyl tert-butyl ether (258 µg/L) were detected. Three 1995 samples and three 1997 samples contained only PCE (at 13 µg/L in 1995 and 1.5 µg/L in 1997). Finally, in six 1999 samples, PCE (20 µg/L) was detected in one sample, collected south of Sunnyside Avenue (BARC Information Repository 1992; Mortensen Engineering 1996; Mortensen Environmental 1997; ATC Associates 1999; Dietz 2000).
The possibility that some surface water and sediment contamination in Indian Creek may have originated at BARC 6, the Biodegradable Site, led to BARC's initial listing on the NPL. Runoff flows and groundwater discharges from the site to the creek. In addition, Indian Creek receives storm water discharge from areas north of BARC, including the Beltsville Industrial Center and development along U.S. Route 1. During the RI for BARC 6, seven surface water and sediment samples were collected, as were eight background samples (collected from the creek upgradient of the site). While levels of chlorinated solvents, metals, bis(2-ethylhexyl)phthalate (a possible laboratory contaminant), heptachlor epoxide, and two PAHs exceeding applicable CVs have been detected in surface water and sediment from Indian Creek, the contaminants detected in 1998 samples only slightly exceeded CVs and were detected at similar concentrations in background samples (Apex 1991, 1994b; BARC 1999; ENTECH 1998c, 2000).
Surface water and sediment samples from Beaver Dam Creek were collected during the investigation of BARC 22, the College Park Landfill, which is adjacent to the creek. The maximum concentrations of arsenic (6.0 milligrams per kilogram [mg/kg]) and of iron (35,500 mg/kg) detected in the five sediment samples exceeded soil CVs. In the five surface water samples, the only contaminant to exceed its drinking water CV was manganese, detected at a maximum concentration of 932 mg/L (ENTECH 1999e).
Other available surface water and sediment samples from the Beaver Dam Creek watershed were collected from locations less likely to be accessed: drainage ditches at four AOCs in Central Farm and from a tributary to Beaver Dam Creek that is near BARC 11. In the surface water samples, the maximum detected levels of antimony (4.4 µg/L), cadmium (14.7 µg/L), manganese (831 µg/L) and bis(2-ethylhexyl)phthalate (240 µg/L) were above drinking water CVs. In the sediment samples, the following contaminants were detected above soil CVs at the indicated maxima: arsenic (5.3 mg/kg), cadmium (10.7 mg/kg), chromium (338 mg/kg), and iron (43,000 mg/kg) (ENTECH 1998g).
Sediment samples collected from wetland areas in the vicinity of the former BARC airfield (in East Farm) which drain to Beaver Dam Creek contained levels of an SVOC, two pesticides, and a PAH above CVs. The contaminants and their maximum detected concentrations were: hexachlorobenzene, 1 mg/kg; dieldrin, 0.53 mg/kg; 4,4'-DDE, 3.4 mg/kg;, and benzo(a)pyrene, 0.48 mg/kg. The only surface water sample from the airfield area to be analyzed was obtained from an inundated borrow pit. In this sample, the pesticide aldrin was measured at a concentration of 0.7 mg/kg, which exceeds the drinking water CV (ENTECH 1998d, 1999f). While analytical data from these sampling events were recently released, the SSP Investigation Report for the AOCs is not yet available. Investigations of other AOCs in this watershed are pending. (See Tables 1 and 2.)
BARC Wastewater Treatment Plants
BARC has two wastewater treatment plants, recently upgraded, that discharge to Little Paint Branch and to Beaver Dam Creek, respectively. Formerly, these plants were out of compliance with their NPDES permits. Reportedly, however, violations were related to conventional water quality parameters, not to toxins. A consent order in place in the mid-1990s to address these violations has been lifted, and BARC is now in compliance with its NPDES permits (Cassell 1999b). Information about whether and to what extent the wastewater facilities previously impacted surface water and sediment on and off site is unavailable.
Evaluation of Potential Public Health Hazards
Although detected levels of certain contaminants in surface water and sediment samples from Indian Creek, Beaver Dam Creek, drainage ditches, and wetlands associated with AOCs exceeded CVs, the public is not exposed to contaminants because recreational use of surface water bodies is not allowed within BARC. CVs are not available for dermal exposures to surface water and sediment. Therefore, analytical results for these media are compared to drinking water and surface soil CVs, respectively. Based on the currently available data for Indian Creek and Beaver Dam Creek, even if people were exposed to the levels of contaminants reported to date, exposure would occur significantly less frequently than assumed by the CVs. Therefore, adverse health effects are not expected to result from exposure to on-site surface water and sediment.
It is expected that appropriate measures will be taken by W.P. Ballard & Company, under regulatory oversight of MDE, to mitigate sources of chlorinated VOCs. MDE plans to require the company to collect samples from the location where the highest levels of solvent-contaminated groundwater discharge from the site to Indian Creek (MDE 1998, 1999a).
In order to verify that contaminant levels are below those that might present possible public health hazards, ATSDR recommends that surface water and sediment samples be analyzed from locations immediately downstream of BARC in areas that people might frequent. Subsequently, it may be desirable to collect more conclusive information on the extent of downstream surface water use than is currently available. Given that there is little sampling and exposure data, ATSDR considers the off-site surface water and sediment exposure pathways an indeterminate public health hazard.
Nature and Extent of Contamination
No fish tissue samples were collected within BARC. The only available samples were collected by MDE from the Northeast Branch of the Anacostia River at the same location from which surface water samples were drawn, more than 4 stream miles below BARC (Forrest 2000). The samples were analyzed for metals from 1985 to 1995 and for organic constituents from 1980 through 1987. Available samples contained concentrations of inorganic arsenic (the maximum concentration was 0.035 mg/kg), chlordane (0.934 mg/kg), DDE (0.0968 mg/kg), and PCBs (0.42 mg/kg) above EPA's Risk-Based Concentrations (RBCs), used as screening values. The mercury level (0.164 mg/kg) also slightly exceeded the RBC in one sample; other samples contained levels of mercury below the screening value.
Fishing is not allowed within BARC. While little fishing is thought to occur immediately downstream of BARC, there is thought to be more significant use of the Northeast Branch for fishing in the vicinity of the sampling station. While the number of gamefish large enough to eat is thought to be low, local residents may sometimes consume the fish they catch (Galli 2000).
Evaluation of Potential Public Health Hazards
To evaluate whether occasional consumers of locally-caught fish might be exposed to harmful levels of contaminants, ATSDR estimated ingestion doses based on the maximum levels of arsenic, chlordane, DDE, and PCBs detected in fish collected from the MDE sampling station on the Northeast Branch of the Anacostia River. ATSDR assumed people consume 6.5 grams of fish per day over the course of a year. This equals 1 to 2 fish meals (of 4 to 8 ounces) per month (EPA 1997). ATSDR assumed that all locally-caught fish consumed contained the maximum levels of contaminants detected in the available samples.
Estimated doses did not exceed ATSDR Minimal Risk Levels (MRLs) for any contaminants except PCBs. The dose of total PCBs (0.00004 mg/kg/day) slightly exceeded the MRL for PCB-1254 (0.00002 mg/kg/day). ATSDR concludes that consuming fish containing the detected levels of contaminants would not cause adverse health effects. ATSDR based its conclusions on the following considerations. Dose levels below MRLs are considered safe. The estimated PCB dose is lower than levels showing effects in published scientific studies (0.005 mg/kg/day). Furthermore, the concentration of PCBs was calculated from a whole fish sample, which is expected to be higher than the level that would be found in the fish fillet, the part people generally eat.
Only limited conclusions can be drawn, however, because of the scarcity of available fish data. Only one sample was analyzed for PCBs (in 1987), and it is not known if the detected level is representative of levels that would be found in other fish in the vicinity of the sampling location. Furthermore, the sample only indicates the level of contaminants present at the time it was collected, and concentrations may have been higher or lower at other times. The available fish samples collected more than 4 stream miles downstream of BARC provide information about concentrations to which people might be exposed at that location, may not represent contaminant concentrations in fish closer to BARC. It is unknown to what extent, if any, BARC activities (or activities upstream of BARC) affect possible fish contamination. It should be noted, however, that relatively low levels of contaminants likely to bioaccumulate in fish have been detected in surface water samples collected within BARC. Several other potential sources of stream contamination are located both upstream and downstream of the facility (ARI 1996). Larger concerns regarding environmental contamination, including possible contamination of fish in the Anacostia River, are being addressed by the cooperative Anacostia River Initiative, spearheaded by the U.S. EPA.
Given the limited data and limited conclusions that can be drawn from them, ATSDR concludes that fish consumption poses an indeterminate public health hazard. ATSDR recommends that a use survey be conducted to determine whether fish are regularly caught and consumed from Indian Creek immediately downstream from BARC. If people are regularly consuming fish they catch from creeks immediately downstream of BARC, ATSDR recommends that fish samples be analyzed from these locations to verify whether contaminant levels might present a possible public health hazard.
Nature and Extent of Physical Hazards
When ATSDR visited the site in September 1995, agency personnel were concerned that the discarded drums, cylinders, canisters, glassware, and other debris discarded in numerous locations throughout the site represented a physical hazard to people who came across them. At that time, ATSDR recommended that BARC install further institutional controls (such as fences and signs) to restrict access to and provide a warning of potential hazards. ATSDR also advised BARC to take appropriate measures, including coordination of its efforts with State regulators, to remove the hazards as quickly as possible (ATSDR-DHAC 1999a, b).
After the 1995 ATSDR site visit, at which the agency was accompanied by the EPA Remedial Project Manger for the site, EPA Region III proposed that BARC undertake a removal action at BARC 9, the Dump Off Odell Road. The boundaries of BARC 9 encompass BARC 26 and ENTECH R3. In 1997, a CERCLA removal action conducted at the AOC removed surface debris from the roughly 70-acre site to mitigate any immediate threat of potential exposure to hazardous substances. In addition, non-CERCLA surface debris removals occurred at the following BARC AOCs in 1997 and 1998: BARC 1, BARC 2, BARC 11, BARC 12, BARC 17, BARC 22, BARC 30, BARC 31, BARC 34, BARC 34A, BARC 35, BARC 36, BARC 44, EPIC 16, EPIC 31, EPIC 34, EPIC 39, FDA 1, FDA 2, ENTECH 7, ENTECH M12, ENTECH M22, ENTECH R1, ENTECH R15, ENTECH R23, and some of the no further action sites. Laboratory bottles, drums, and other containers that may have contained chemicals or other hazardous substances were removed, in addition to metal and construction debris that posed physical hazards.
During the 1999 site visit, ATSDR observed that the amount of on-site surface debris had been dramatically reduced since the 1995 trip (BARC 1999). The only apparent potential physical hazard identified was the AOC ENTECH R5. The AOC, which is not fenced, consists of a generally overgrown wooded area, containing construction rubble, the foundation of an old building used until the 1960s, in-ground metal frames, and other debris. A BARC employee reported that chemicals might have been dumped nearby prior to the abandonment of the building, but the history of the site is not well documented. Sampling to characterize environmental media at the site was conducted in 1999. A removal of remaining debris will occur after sampling results become available. There is currently a public playground (Sunnyside Neighborhood Playground) about 200 feet south of this AOC.
Evaluation of Potential Public Health Hazards
It is currently possible for individuals to trespass on ENTECH R5 unimpeded. No signs warn the public of the possible physical hazards it contains. As a precautionary measure, ATSDR recommends that BARC place a fence around the site until it is remediated. Remediation is reportedly planned (Schoppet 1999e). Additionally, it may be possible for trespassers to encounter physical hazards at other BARC AOCs, as they are not all fenced or marked by signs. Access controls are particularly important in areas that might be accessible to children. Therefore, ATSDR recommends that BARC take all necessary measures to prevent access by the public, especially children, to AOCs containing physical hazards. ATSDR concludes that the potential for harm coming to the public from exposure to physicals hazards remains.
ATSDR identified the following community health concerns through contact with local officials, local agencies, and BARC representatives, as well as its review of site documents, including the Community Relations Plan prepared by the ARS:
- Could utility workers be exposed to contaminants while working within BARC property?
- Could contaminants related to BARC operations enter water or sewer pipes?
- Could contamination enter pipelines and be transported to the buildings the pipelines serve?
- Could subsurface contamination potentially migrate along pipeline bedding?
- Is the cancer rate in the part of Greenbelt closest to BARC higher than the average rate across the State, and, if so, is this related to exposure to pesticides or Agent Orange (a defoliant used during the Vietnam War), which is rumored to have been tested at BARC?
- Were there any adverse effects from an incident in April 1994 when 2,4-D and another herbicide, Banvil, were sprayed on fields adjacent to Greenbelt and a change in the weather transported the chemicals to off-site locations?
- Does BARC take any steps to reduce the odor caused by spreading manure on fields?
VOCs, SVOCs, pesticides, PCBs, and metals have been detected in soil and groundwater at AOCs near water and sewer lines. However, it is not known whether contamination might affect specific areas that workers would contact. ATSDR has facilitated communication between WSSC and BARC and recommends that all interested parties continue to work together to determine if there are any such areas. After this determination is made, if requested, ATSDR will assist in evaluating whether sufficient contamination exists to present a potential public health hazard in specific areas and whether protective measures are advisable. Information about the types of personal protective equipment that could be used by personnel working in areas of contamination is available from the National Institute for Occupational Safety and Health.
Water and/or sewer lines are located close to numerous BARC AOCs. However, whether any contamination related to these sites is co-located with pipelines is not well understood at this time. ATSDR has facilitated communication between WSSC and BARC so that the two parties can better identify any such areas. ATSDR recommends that BARC remedial project managers coordinate with BARC public works managers to determine if any BARC pipelines intersect contamination. If it is determined that contaminants might affect pipes, ATSDR will, upon request, assist in evaluating sampling data that reflect contaminant concentrations in these areas to determine whether there are potential public health hazards.
ATSDR has not received any information about the locations of BARC pipelines. The only groundwater contamination plumes ATSDR has identified near WSSC pipelines are in the vicinity of BARC 6, BARC 22, and EPIC 16, as well as a plume of PCE and its breakdown products thought to originate from the Ballard site (near EPIC 16 and BARC 6). Detected concentrations of PCE at BARC 6 have been below 375 µg/L, except in an April 1998 sample that contained 5,100 µg/L of PCE (ENTECH 2000a). WSSC sewer lines are east and west of the AOC, and there are water lines to the west. A WSSC sewer line is about 500 feet north of BARC 22, and a water line is about 800 feet to the west (Schoppet 2000). Groundwater flow is to the southeast, towards Beaver Dam Creek flow adjacent to the creek may be southwestward and therefore possibly toward the WSSC lines. Although sampling was conducted at EPIC 16 in 1999, validated results are not yet available. There are water pipes west of EPIC 16 and sewer pipes to the north, east, and south.
The highest concentrations of chlorinated solvents have been detected in a plume associated with the Ballard property and extends through the Beltsville Industrial Center (BIC), across the B&O Railroad right-of-way, and onto the BARC property. Using conservative theoretical assumptions and limited information concerning actual contaminant levels in groundwater downgradient of the Ballard site, ATSDR evaluated concentrations of a contaminant that could theoretically be found within pipelines, then calculated the minimum mass transport rate that could yield contaminant concentrations above health-based guidelines. This evaluation indicated that, under ATSDR's conservative scenario, the potential exists for some contaminants to reach concentrations exceeding health-based guidelines within water supply pipes within the BIC. A more detailed discussion of this evaluation is provided in Appendix C.
The actual mass transport rates into water pipes for PCE and TCE may or may not exceed the levels calculated by ATSDR. To substantiate conclusions drawn from this evaluation, ATSDR recommends that WSSC coordinate with BARC and MDE (which is overseeing remedial activities at the Ballard site) to determine mass transport rates for PCE and TCE into the water lines. This evaluation is highly dependent on the characteristics of the pipes and the properties of their gasket materials. ATSDR also recommends samples of water from these lines be collected and analyzed to determine the levels of contamination present so that appropriate measures can be taken to protect people from any potential public health hazard posed by this contamination. Finally, ATSDR recommends that samples be collected from any taps served by small diameter water lines that are located in areas of groundwater contamination.
Because levels of contaminants immediately adjacent to pipes are for the most part unknown, ATSDR cannot fully evaluate the potential public health hazard posed by the subsurface contamination. However, ATSDR is available to assist, if requested, with the evaluation of any sampling results submitted to us from areas where contamination might affect pipelines.
Exposure to contaminants that enter sewer pipes is not expected to pose a public health hazard. Sewer pipes do not convey water to homes or businesses, and organic vapors are not expected to be transported through sewer lines into nearby homes, offices, or businesses. The mechanisms that prevent sewer gases from backing up into buildings would be expected to prevent all vapors, including those from organic contaminants, from reaching buildings through sewer pipes.
The potential exists for contamination to enter water pipelines and be carried to nearby buildings, but the contaminant concentrations reached under these circumstances is unknown. As discussed in Appendix C, contaminant levels in pipes would reach the highest concentrations in areas where pipes of small diameter directly contact groundwater contamination. In the absence of data revealing levels of contaminants present in water lines or taps serving buildings near such areas, ATSDR cannot fully evaluate the potential public health hazard. If samples are collect to assess these levels, ATSDR will assist, if requested, in their evaluation.
If groundwater contamination directly intersects buried pipelines, there may be preferential migration of contaminants within the bedding material. ATSDR recommends that BARC remedial project managers work with WSSC and BARC public works managers to determine if there are any such areas. If they exist, ATSDR recommends that air and water samples be taken from the bedding material. If sampling results are provided to ATSDR, we will help assess any potential public health hazard.
BARC investigated this concern and found no evidence in support of it. According to Dr. Sharin DeSilva, Acting Director of the Maryland Office of Environmental Health, the average cancer rate in Greenbelt (based on cancer reports for the 20770 ZIP code from 1989 through 1991) is the same as the national average and actually slightly lower than the average for the state of Maryland as a whole. Nevertheless, Dr. DeSilva indicated that, if residents of Greenbelt remain concerned, they may request a "cancer cluster study" for an area smaller than a ZIP code by contacting the Prince George's County Health Department. This offer was communicated by ARS to those who had expressed the concern, as well as to the Office of the Mayor of Greenbelt (USDA-ARS-BARC 1996).
Further, an extensive investigation during the early and mid-1990s showed that Agent Orange was never tested or applied in any manner at BARC. The rumors about Agent Orange at BARC arose from an article in the Summer 1989 issue of Maryland magazine. The author of the article later confirmed that he was not asserting that Agent Orange was used at BARC; rather, he was referring to the herbicide 2,4-D, a commonly available, over-the-counter product that is still used. Agent Orange is a mixture of several herbicides, only one of which is 2,4-D, and the significant health problems attributed to Agent Orange were attributed to its dioxin component, not to 2,4-D. The only testing at BARC related to these chemicals was conducted within laboratories during the 1970s, under strict exposure controls and with no field testing, of products other than Agent Orange to determine if they contained the same dioxin impurity found in Agent Orange (USDA-ARS-BARC 1996).
Since there is no evidence at the present time that the part of Greenbelt adjacent to BARC experiences a higher cancer rate than the rest of the state, it follows that there currently is no evidence that a higher rate is related to pesticide use at BARC. With regard to pesticide use, BARC meets or exceeds all MDE standards. Furthermore, the facility has made "integrated pest management," a strategy designed to keep pesticide use to a minimum, a high priority in its operations. Precautions designed to prevent airborne drift and to prevent exposure to outside receptors are also followed.
ATSDR has been advised that in 1994, as a result of an unexpectedly quick rise in temperature, the chemicals that BARC had sprayed on its fields--2,4-D and Banvil--apparently changed from their liquid state to a vapor and were carried by a breeze to a nearby section of Greenbelt. A temperature inversion then caused the chemicals to be deposited on approximately 500 trees, causing their leaves to curl.
BARC representatives met with citizens concerned about their trees and with a representative from the Office of Congressman Steny Hoyer shortly after this incident and again the following spring. In addition, representatives of the manufacturers of the chemicals, as well as independent arborists, examined the damage and their consensus was that the trees probably would be fine. As an extra measure of care, they recommended that property owners temporarily give the affected trees an inch of water a week. BARC also arranged for an arborist to deep feed the trees at the appropriate time later in the year. Finally, BARC assumed all costs associated with the incident and an examination of the trees the next year found them healthy and without any signs of damage (USDA-ARS-BARC 1996; BARC 1999).
It is ATSDR's understanding that no residents raised concerns about their health due to this incident and that concern was related instead to damage to trees near BARC (BARC 1999). No human health issues are likely to have resulted from this incident.
In part to keep the use of chemicals to a minimum, BARC recycles animal wastes generated at the research center as fertilizer for grass and crop lands. BARC nevertheless is doing everything it believes reasonable to accommodate community concerns. For example, BARC is using a new high-tech bacteria digester to reduce manure odors to an absolute minimum before composting. In addition, if there are areas where resident complaints continue, BARC plans to maintain a buffer zone on which no compost will be spread (USDA-ARS-BARC 1996). Humans can detect odors when very low concentrations of certain elements are present; ATSDR has not identified any evidence that odors on the site represent a matter of public health concern.
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 may 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 are also 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 BARC, as part of the ATSDR Child Health Initiative.
ATSDR has attempted to identify populations of children in the vicinity of BARC and any completed exposure pathways to these children. Roughly 9,580 children under the age of 10 lived in Districts 1 and 10 in northern Prince George's County in 1990, according to the U.S. Census. There is a small childcare center at BARC, and a childcare center is slated to open at the USDA Office Complex. At both facilities, however, outdoor play is supervised and children are expected to remain within fenced playgrounds.
ATSDR has evaluated the likelihood of children being exposed to contamination at BARC at levels of health concern. On the basis of available data, ATSDR has not identified site contamination that would pose a unique health hazard for children.
Based on currently available information, ATSDR did not identify a potential hazard to individuals, including children, who consume groundwater on site. However, no information about whether children might currently or might have in the past consumed groundwater from private wells off site is available. ATSDR recommends sampling of the wells at the residential inholdings and other private wells identified near the site to confirm that no exposure has occurred at levels of health concern to individuals reliant on off-site wells. ATSDR also recommends sampling of any taps in the area served by small diameter water supply pipes that intersect groundwater contamination. ATSDR will evaluate new groundwater data as they are made available to us.
Information about child exposure to surface water and sediment downgradient of the site is incomplete. ATSDR recommends that levels of BARC-related contaminants in surface water and sediment immediately downstream of the facility be measured. If contaminants of concern are identified, ATSDR also recommends that not only the locations used by the public, but also the nature and frequency of exposures, be fully characterized. To evaluate the public health implications of sampling data, it will be necessary to understand not only the locations of exposure, but also the nature and frequency of exposures.
Like adults who live at or in the vicinity of BARC, some children may access certain areas of the site. In general, ATSDR did not find evidence that children are regularly accessing the BARC AOCs (where soil contamination and physical hazards may be present). Therefore, soil contamination and physical hazards are not expected to pose a health hazard to children. As previously stated, however, ENTECH R5 is near a neighborhood playground. This unfenced AOC contains debris that could pose a physical hazard to trespassers. As a precautionary measure, ATSDR recommends that a fence be placed around ENTECH R5 until physical hazards are removed.
Access controls are particularly important in areas that might be accessed by children, and not every AOC at BARC is fenced. ATSDR further recommends that BARC evaluate access controls at all AOCs where public access is likely.