PUBLIC HEALTH ASSESSMENT
NAVAL CONSTRUCTION BATTALION CENTER
(a/k/a DAVISVILLE NAVAL CONSTRUCTION BATTALION CENTER)
DAVISVILLE, WASHINGTON COUNTY, RHODE ISLAND
The Naval Construction Battalion Center (NCBC), Davisville is a decommissioned military installation located in the towns of North Kingstown and East Greenwich, Rhode Island, that once occupied 1,284 acres. Activities at NCBC, Davisville began in 1942. During its years of operation, NCBC, Davisville was used primarily as a training facility for construction operations, and as an area for construction material storage and freight yards. At one point, the facility housed as many as 15,000 enlisted personnel and 350 officers. North Kingstown contains several large businesses and industrial firms. East Greenwich is primarily a residential area with some light manufacturing.
NCBC, Davisville was added to the U.S. Environmental Protection Agency's National Priority List on November 15, 1989, because of contamination at Calf Pasture Point and Allen Harbor Landfill. At the request of the Navy, the Agency for Toxic Substances and Disease Registry (ATSDR) visited Allen Harbor Landfill at NCBC, Davisville, on April 13, 1994, to determine whether Allen Harbor Landfill was safe for future use by nondefense organizations. In October 1995, ATSDR released a health consultation for NCBC, Davisville, which addressed these safety issues and recommended consumption restrictions for shellfish in Allen Harbor. On its site visits in November 1998 and August 1999, ATSDR identified no immediate public health hazards.
ATSDR reviewed and evaluated groundwater data for NCBC, Davisville. Past and current exposures to contamination have been avoided because contamination is either downgradient of identified public and private wells, or wells are too far away to be affected by site contaminants. Future exposure to groundwater contamination at Calf Pasture Point (Site 07) and Allen Harbor Landfill (Site 09) is not expected since deed restrictions should prevent groundwater use at these sites. For these reasons, ATSDR concludes that groundwater contamination from NCBC, Davisville poses no public health hazard.
Navy property is affected by groundwater contamination coming from the former Nike Battery Site, which is not part of NCBC, Davisville. The U.S. Army Corps of Engineers (USACE) is conducting environmental investigations of this site. The volatile organic contaminants in deep groundwater also extend into a residential area to the north. Residential well samples indicated that most private wells have not been impacted. However, one private well was found to be contaminated with low levels of volatile organic contaminants. Drinking water containing these low levels is not anticipated to cause adverse health effects. ATSDR supports USACE in their continuation of investigations with special focus on determining the likelihood of future private well contamination from the former Nike Battery Site. We also support the USACE and Navy measures to prevent future exposure to contaminated groundwater at the former Nike Battery Site and beneath the Navy property through source remediation and land use restrictions.
ATSDR also reviewed available surface soil data. Areas with elevated levels of lead and polychlorinated biphenyls (PCBs) have been remediated and had limited accessibility in the past. This includes the Calf Pasture Point Area which has been transferred to the Town of North Kingstown through the Department of the Interior's Federal Lands to Parks Program. Soil contamination was also found at Allen Harbor Landfill, but access to the landfill has been and continues to be restricted by fencing. The town of North Kingstown is also in the process of acquiring this land. The landfill is capped to prevent contact with contaminated soils, and appropriate deed and land use restrictions are in place to prevent excavation or disturbances of the landfill cap. For these reasons, ATSDR concludes that soil contamination at NCBC, Davisville poses no public health hazard.
ATSDR reviewed surface water and sediment data from Allen Harbor and other surface water bodies at or near NCBC, Davisville. A few chemicals were detected in surface water and sediment at levels that slightly exceeded ATSDR's health-based comparison values for drinking water and soil, respectively. People do not swim in local streams or ponds, but do swim in the entrance channel area to Allen Harbor and along local shoreline beaches. Exposure to the few contaminants detected in Allen Harbor surface water and sediment likely occurs infrequently and for short durations. Such limited dermal contact and incidental ingestion exposure to the low levels of contaminants detected is not expected to cause adverse health effects. ATSDR concludes that surface water/sediment contamination from NCBC, Davisville poses no public health hazard.
ATSDR reviewed data from the 1990s on chemical contaminants in shellfish collected from Allen Harbor and Narragansett Bay. The data indicate the shellfish in these areas have accumulated elevated levels of contaminants, including PCBs, polycyclic aromatic hydrocarbons (PAHs), pesticides, and metals. ATSDR concludes that shellfish contamination from NCBC, Davisville posed a public health hazard prior to 1984, when the Rhode Island Department of Environmental Management (RIDEM) instituted a shellfishing ban in Allen Harbor due to bacteriological contamination. Shellfish data collected in the 1990s indicated a chemical hazard driven primarily by methylmercury, and to a lesser extent by PCBs. Although the original ban was based on bacteriological contamination, ATSDR concludes that a current and future public health hazard could exist from chemical contamination in shellfish if the ban is not continued or adhered to. ATSDR supports the shellfishing ban for Allen Harbor and advises people to adhere to it. We also recommend that sources contributing to mercury in shellfish in the NCBC, Davisville area be identified, if possible.
No edible fish tissue data have been found for review. ATSDR recommends that state agencies responsible for fish toxicity issues (i.e., RIDEM and the Rhode Island Department of Health) collect edible fish tissue samples from Allen Harbor and Narragansett Bay waters and analyze the samples for PCBs, PAHs, pesticides, and metals.
Although the land of the former Navy facility will be developed further in the future, it will not be used for residential areas. Because there are no known current or future public health hazards associated with the Naval Construction Battalion Center (NCBC), Davisville, ATSDR classifies this site as no apparent public health hazard (exposures may occur but not at levels expected to cause adverse health effects).
Table 1. Exposure Hazards Summary--NCBC, Davisville
| Exposure Scenario | Time Frame | Exposure Yes/No |
Hazard | Actions Taken/Recommended |
| Exposure to groundwater in the NCBC, Davisville vicinity. | Past Current Future |
No for past and current. Future exposures to the Nike plume are possible. | No past or current hazard. Future hazard possible due to Nike plume. | • The plumes will continue to be monitored and deed restrictions will prevent any future use of contaminated water for potable purposes at Sites 07 and 09. ATSDR supports USACE and the Navy in their continued investigations of the Nike Battery site contamination. |
| Dermal contact with surface soil at NCBC, Davisville sites. | Past Current Future |
No | No hazard | • The Navy has conducted removal actions to excavate and
dispose of contaminated on-site soils. • The Navy has or will initiate final and interim remedial actions at: Site 05, Site 06, Site 08, Site 10, Site 11, Site 12, Site 13, Site 14, and Study Area 15. • Additional investigations at the former Nike Battery Site will be conducted by the U.S. Army Corps of Engineers and by the Navy for IRP Site/Study Areas 01, 02, 03, 04, and 16. |
| Dermal contact with surface water and sediment in the NCBC, Davisville vicinity. | Past Current Future |
Minimal--local residents do not drink local surface water and swimming is limited. | No hazard | • As a precautionary measure, ATSDR should review any future data. |
| Consumption of fish found in the NCBC, Davisville vicinity. | Past Current Future |
Yes, exposure is likely. | No data on edible fish were found for review. | • No data are currently available to characterize contaminant uptake in fish found near NCBC, Davisville. Because fish are migratory and may be accumulating contaminants from multiple sources, ATSDR recommends that the RIDEM and RIDOH (the lead state agencies responsible for fish toxicity issues) sample fish near NCBC, Davisville. |
| Consumption of shellfish found in the NCBC, Davisville vicinity. | Past Current Future |
Yes (Minimal, if any exposure, since the 1984 shellfishing ban). | Public health hazard prior to the ban in 1984. No hazard since 1984 if the shellfishing ban continues and is adhered to. |
• Exposure estimates, based on 1991 data, show that consumption
of contaminated shellfish in the past posed an increased risk of adverse
health effects. No data are available prior to 1991. • Exposure estimates, based on data from the mid-1990s, show that consumption of contaminated shellfish still poses an increased risk of adverse health effects. The risk is driven primarily by mercury contamination. Although the original shellfishing ban was issued based on bacterial contamination, ATSDR supports a shellfishing ban for Allen Harbor due to chemical contamination in shellfish. |
Site Description and Operational History
The Naval Construction Battalion Center (NCBC), Davisville is a decommissioned military installation located approximately 18 miles south of Providence, Rhode Island (Figure 1). The former facility lies in the towns of North Kingstown and East Greenwich with a large portion adjacent to Narragansett Bay (TRC 1991). The facility once occupied 1,284 acres and contained three distinct areas (Figure 2): the Main Center (839 acres), the West Davisville Storage Area (70 acres), and Camp Fogarty (375 acres) (TRC 1991; Ecology and Environment 1994; Stone & Webster 1998). NCBC, Davisville currently occupies approximately 750 acres (Navy 2000a). Just south of the facility lies the decommissioned Naval Air Station Quonset Point.
The history of NCBC, Davisville is tied to the history of Quonset Point. In 1939, the Navy acquired Quonset Point to establish a Naval Air Station (EA 1997a). Operations at Quonset Point expanded in 1942 with the establishment of the Advance Base Depot (ABD), Davisville. In late 1942, the Naval Construction Training Center, called Camp Endicott, was established at ABD, Davisville. During the first 3 years of operation, Camp Endicott trained more than 100,000 military personnel, officially nicknamed "Seabees." After World War II, the majority of Seabee activities were relocated to NCBC, Port Hueneme, California, and the number of active duty Seabees at NCBC, Davisville was greatly reduced (Navy 1994). Unlike Quonset Point, ABD, Davisville was inactive between World War II and the Korean War. In 1951, ABD, Davisville became the Headquarters, Construction Battalion Center, which trained military personnel and loaded ships for the Korean and Vietnam Wars (EA 1997a).
The number of mobile construction battalions increased during the 1960s. In 1968, NCBC, Davisville was the home port of 10 battalions (approximately 8,500 military personnel) and employed approximately 1,200 civilians. During the 1970s, manpower reductions at NCBC, Davisville resulted in the relocation of Davisville Seabee Battalions to other facilities. In the late 1970s and 1980s, the Naval Construction Force and Seabee Reserves used NCBC, Davisville (Navy 1994).
All Navy activities were decommissioned at Quonset Point in 1974. In 1980, the Navy sold Quonset Point and the two Davisville piers to the Rhode Island Port Authority (now the Rhode Island Economic Development Corporation) (TRC 1991). NCBC, Davisville was approved for closure under the Department of Defense Base Realignment and Closure Program in October 1991 (Navy 1998b). The Navy transferred Camp Fogarty, the only portion of the facility located in East Greenwich, to the U.S. Department of the Army in December 1993. Camp Fogarty currently belongs to the Rhode Island National Guard (Stone & Webster 1998). On March 25, 1994, NCBC, Davisville was decommissioned and on April 1, 1994, it was officially closed. Northern Division, Naval Facilities Engineering Command currently serves as the facility caretaker (EA 1997a).
While NCBC, Davisville was active, it primarily served as a construction operations training facility, and as freight yards and storage for construction materials (Stone & Webster 1996). Some operations and waste disposal practices at the facility contaminated the groundwater, soil, sediment, and shellfish in the area. Paint thinners, solvents, asphaltic material, transformer and waste oils, calcium hypochlorite, non-corrosive decontamination agents, and photographic wastes were either poured onto the ground or buried in ditches. Also, transformers containing polychlorinated biphenyl (PCB)-contaminated oil leaked onto the ground. The Allen Harbor Landfill received various types of wastes from both NCBC, Davisville and NAS Quonset Point from 1946 to 1972 (EA 1997a).
Remedial and Regulatory History
The Navy Assessment and Control of Installation Pollutants (NACIP) program conducted the first investigation into waste disposal practices at NCBC, Davisville. The first phase of the NACIP program was the initial assessment study (IAS), involving personnel interviews and a records review. The IAS, completed in 1984, identified 14 potentially contaminated sites. The second phase of the NACIP program was a confirmation study to investigate 13 of the 14 IAS sites (Site 01 was not investigated). The first part of the confirmation study, a semi-quantitative verification step, sampled surface soil, groundwater, marine surface water, and harbor sediments and clams to confirm or deny the presence of contamination (TRC 1987, 1991).
In 1988, the NACIP Program was modified and renamed the Installation Restoration Program
(IRP). The Navy then initiated a remedial investigation/feasibility study (RI/FS). In November
1989, NCBC, Davisville was added to the U.S. Environmental Protection Agency's (EPA) 
National Priorities List because of contamination at Calf Pasture Point and Allen Harbor Landfill
(EPA 1999d). The Phase I remedial investigation report, released in May 1991, included 10 of
the 13 sites investigated during the verification step of the confirmation study (TRC 1991). The
Navy, EPA, and Rhode Island Department of Environmental Management (RIDEM) agreed that
sites not investigated as part of the Phase I remedial investigation would be designated study
areas and investigated under a Study Area Screening Evaluation (SASE) program.
In March 1992, the Navy, EPA, and RIDEM entered into a Federal Facilities Agreement (FFA). The FFA delineated each agency's investigation and cleanup responsibilities at NCBC, Davisville (Stone & Webster 1998). The Navy requested a modification of the FFA schedule in September 1998 (Navy 1998b).
Under the FFA, three Phase II reports were produced for NCBC, Davisville in 1994: a Site 08 report; a Site 09 report; and a report for Sites 02, 03, 06, 07, 10, 11, and 13 (Site 05 was not investigated after Phase I). A supplemental Phase II remedial investigation included additional information on Sites 03, 07, and 09. In the same year, the SASE program issued SASEs for the following areas: Study Area 01, Study Area 04, Study Area 15, and the Calf Pasture Point munitions bunkers.
The Navy also conducted three major Phase III remedial investigations and published results in reports for Site 09; Site 07; and Sites/Study Areas 01, 02, 03, and 04. The RIs for Sites/Study Areas 01, 02, 03, and 04 included an investigation of the groundwater underneath the nearby Nike Battery Site. The Nike Battery Site, a former Army facility, is not part of NCBC, Davisville, but is addressed in this public health assessment document because of underlying groundwater contamination and community concerns about the site.
Environmental Baseline Survey (EBS) investigations began in 1994. These investigations were designed to determine if hazardous substances or petroleum products had been disposed of or released into the environment. The information gathered has and will be used to support environmental restoration activities and to make decisions about the suitability of transferring NCBC, Davisville property (EA 1998b). On February 8, 1999, EPA proposed further investigation of one EBS area (EBS Review Item 28) (EPA 1999a). In March 3, 1999, this EBS site was officially designated Study Area 16 and then upgraded to Site 16 in August 1999. Site 16 includes the Former Creosote Dip Tank and Fire Fighting areas (EPA 1999b; Navy 2000a). A remedial investigation is planned to be completed for this site in September 2002 (EPA 2000a).
The IRP at NCBC, Davisville currently contains 13 sites (Figure 3) and 3 study areas (Figure 4) (Figure 4). Table 1 contains summary information for the off-site Nike Battery Site and all sites and study areas under the NCBC, Davisville IRP. Remedial investigations have been completed at Sites/Study Areas 05, 06, 07, 08, 10, 11, 12, 13, 14, and 15. Remedial actions have also been completed at Sites/Study Areas 02, 04, 09, and 16. Record of Decision (ROD) documents have been issued for the following sites: Sites 07, 09, 12, and 14; the soil at Site 05; and the soil and groundwater at Sites 06, 08, 10, 11, and 13. A draft final ROD and responsiveness summaries for Study Areas 01 and 04 and Sites 2 and 3 are scheduled for release in July 2001 (Navy 1998b, EPA 2000a, 2000c).
The remediation at the Allen Harbor Landfill (Site 09) is complete (Navy 2000a). As part of the remediation efforts, a cap has been placed over the landfill to prevent public exposure to landfill contents. The Navy may re-vegetate the landfill area to prevent erosion. Erosion if left unchecked could compromise the integrity of the soil cap beneath the surface of the landfill (RIDEM 2000). The Navy and EPA recently agreed on a long-term monitoring for the groundwater beneath the site (Navy 2000a). The Allen Harbor Landfill will be transferred to the town of North Kingstown in the near future. Deed restrictions and institutional controls accompanying the transfer will prevent land uses that could disturb the integrity of the landfill cap.
The Agency for Toxic Substances and Disease Registry (ATSDR) visited the Allen Harbor Landfill at NCBC, Davisville, on April 13, 1994, at the request of the Navy. ATSDR was asked to determine whether Allen Harbor Landfill is safe for future use by nondefense organizations.
In October 1995, ATSDR released a health consultation for NCBC, Davisville (ATSDR 1995). If Allen Harbor is ever reopened for shellfishing, ATSDR recommended rates for shellfish consumption and that oysters not be consumed (see Evaluation of Food Chain Exposure Pathway in this report). At the time the health consultation was prepared, the landfill was considered a potential hazard to trespassers, building and construction workers, and future residents because of soil contamination and physical hazards. ATSDR concluded that no structure should be built on the landfill and that the physical hazards be rendered safe. Although levels of volatile organic compounds (VOCs) in groundwater under the landfill were of health concern, at the time of the health consultation (and to date) no one was drinking (or currently drinks) the groundwater (ATSDR 1995).
On November 18-19, 1998, ATSDR conducted a second site visit. During the visit, ATSDR toured the facility and met with Navy representatives, state and federal regulators, the technical assistance grant recipient, and community members (ATSDR 1998). Due to a change in technical staff, ATSDR visited the site again on August 18, 1999.
In 1942, the NCBC, Davisville facility housed 15,000 enlisted personnel and 350 officers (EA 1997b). In 1968, NCBC, Davisville employed approximately 8,500 military personnel and 1,200 civilians (Navy 1994). On-base family housing was located in subparcel 31 near Narragansett Bay. The barracks were located in subparcel 7A in the Administrative Triangle section of the Main Center (Navy 1999b).
NCBC, Davisville is located in the towns of East Greenwich and North Kingstown. At the time of the 1990 U.S. census, 11,865 people lived in East Greenwich and 23,786 people lived in North Kingstown (EA 1997b). The estimated residential population living within one mile of the facility is 10,339 (Figure 5). Figure 5 provides additional demographic information.
Land Use and Natural Resources
The town of North Kingstown contains several large businesses and industrial firms. East Greenwich is primarily a residential area with some light manufacturing (EA 1997b).
NCBC, Davisville is on the Seaboard Lowland coastal belt of the New England physiographic province (EA 1998f). The portion of NCBC, Davisville in North Kingstown is relatively flat, while Camp Fogarty has more relief (TRC 1991). Sandhill Brook, Mill Creek, and Hall Creek flow through NCBC, Davisville. Davol and Frys Ponds are located to the east of the Main Center, while Saw Mill and Sandhill Ponds are located off site in a residential area northwest of the Main Center (TRC 1991).
A significant portion of Allen Harbor, an estuary of Narragansett Bay, is bordered by Navy property (TRC 1991). Allen Harbor is a shallow marine harbor which contains two boating marinas. Shellfishing in Allen Harbor was banned in 1984 due to bacteriological (fecal coliform) contamination. To the north of Allen Harbor lies Calf Pasture Point and then Mountview residential area. North Kingstown once managed a beach at Calf Pasture Point, a peninsula located in the northeastern portion of NCBC, Davisville (EA 1997b). Two softball fields located in the Main Center east of building C-107 have been used by residents of North Kingstown (TRC 1991).
RIDEM classifies Narragansett Bay surface water in the NCBC, Davisville vicinity as Class SC sea water, defined as water which supports:
During its site visits, ATSDR observed people swimming in the entrance channel area to Allen Harbor and along local shoreline beaches. Local brooks, creeks, and ponds are not used for swimming.
NCBC Reuse
In January 1994, the Comprehensive Reuse Plan for NCBC, Davisville was issued to assist the Base Reuse Committee in making decisions on how to best utilize the former Navy facility. The document included a preferred development plan (Maguire Group 1994). The development plan focuses primarily on general and light industrial, institutional/office, and open space/conservation uses (Navy 1994). None of the land from the former Navy facility will be developed in the future as residential areas. In fall 1998, a portion of NCBC, Davisville was transferred to the Bayside Medical Center (1.3 acres) (EA 1998e). More recently, the Pier Support Area (96 acres), Administrative Triangle (125 acres), and West Davisville (70 acres) were transferred to the Rhode Island Economic Development Corporation (RIEDC). Calf Pasture Point was transferred to the town of North Kingstown, through the Department of Interior's Federal Land to Parks Program (RAB 2001). Additional land transfers will include the transfer of Allen Harbor Landfill to the Town of North Kingstown (RAB 2001) and additional land to RIEDC (EPA 1999c).
Current land use restrictions exist at Calf Pasture Point (Site 07), where well drilling and groundwater use have been prohibited. And following the transfer of Allen Harbor Landfill (Site 09) to the town of North Kingstown, restrictions will include a prohibition on digging and dirt biking to protect the remedial cap and groundwater use as a source of drinking water (Navy 2000a; EPA 2000a).
Quality Assurance and Quality Control
In preparing this public health assessment (PHA), ATSDR reviewed and evaluated information provided in the referenced documents. Documents prepared for the Comprehensive Environmental Response, Compensation, and Liability Act 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 PHA are from Navy remedial site investigations, EBSs, and SASEs for study areas. In addition, selected shellfish data from a Risk Assessment Pilot study that were not part of the remedial investigations at NCBC, Davisville were used. Based on our evaluation, ATSDR determined that the quality of environmental data available in most site-related documents for NCBC, Davisville is adequate to make public health decisions. ATSDR did not rely on NCBC, Davisville data from the verification step of the Confirmation Study due to the semi-quantitative analytical methods used.
EVALUATION OF ENVIRONMENTAL CONTAMINATION AND POTENTIAL EXPOSURE PATHWAYS
In this section, exposure pathways are evaluated to determine whether people accessing or living near NCBC, Davisville could have been, are, or will be exposed to facility-related contaminants. 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 from available scientific literature on exposure and health effects. These values, which are defined for each of the different media, reflect the estimated maximum contaminant concentration for a given chemical that is not likely to cause adverse health effects, given a standard daily ingestion rate and standard body weight. If contaminant concentrations are above CVs, ATSDR further analyzes exposure variables (for example, duration and frequency) and the toxicology of the contaminant. It should be noted that because CVs do not represent thresholds of toxicity, exposure to contaminant concentrations above CVs will not necessarily produce health effects. In fact, ATSDR CVs are designed to be many times lower than levels at which no adverse health effects were observed in experimental animals or epidemiological studies. A public health hazard exists only if people come in contact with, or are otherwise exposed to harmful levels of contaminated media. The exposure evaluation process is summarized in Figure 6 and an evaluation of public health hazards is presented in Table 2.
After an initial review of potential health hazards at NCBC, Davisville, ATSDR identified the groundwater, soil, surface water/sediment, and food chain pathways as requiring further evaluation. Following the strategy mentioned 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 3 and describes them in more detail in the sections that follow. To acquaint readers with terminology used in this report, a list of CVs and a glossary are included in Appendices A and B, respectively. In addition, Appendix C presents methods and assumptions used to estimate exposures and support some of the public health assessment conclusions for the food chain pathway.
Evaluation of Groundwater Exposure Pathway
Regional Hydrogeology and Groundwater Use
Bedrock underneath most of NCBC, Davisville is part of the Pennsylvanian Rhode Island Formation (TRC 1991). Camp Fogarty, however, is located above bedrock from the Precambrian Blackstone Formation. Depth to bedrock in the vicinity of NCBC, Davisville ranges from ground surface to 90 feet. Well yields from bedrock aquifer formations are low; therefore, bedrock is not the principal source of water for the area.
The primary source of potable water in the NCBC, Davisville area is the Potowomut-Wickford Aquifer. This aquifer is generally found in the glacial deposits located above the bedrock. The groundwater beneath NCBC, Davisville is unconfined--that is, the upper zone of saturated groundwater is not restricted by an impermeable layer (TRC 1994c). All sites and study areas except the Camp Fogarty Disposal Area (which overlies a crystalline aquifer) overlie the Potowomut-Wickford Aquifer (TRC 1991). The groundwater in this aquifer in the NCBC, Davisville vicinity generally flows west to east, towards Narragansett Bay (TRC 1991).
Three hydrogeological zones are generally used when classifying groundwater at NCBC, Davisville. These include the shallow groundwater zone (usually at the water table), deep groundwater zone (usually the region above competent bedrock), and bedrock groundwater zone.
No drinking water wells are located on NCBC, Davisville property. A total of seven public water supply wells are located near NCBC, Davisville, and provide some of the water used by NCBC, Davisville, North Kingstown, and East Greenwich (TRC 1991). These wells range from 61 to 118 feet deep and draw from the Potowomut-Wickford Aquifer. Public water supply wells are located upgradient (north and west) of NCBC, Davisville, and water from the wells meets all state and federal drinking water standards (TRC 1994c). Each of the seven public water supply wells lies at least 1 mile away from the nearest NCBC, Davisville IRP site. In addition, none of the NCBC, Davisville IRP Sites/Study Areas are located in wellhead protection zones or groundwater capture zones for these wells (TRC 1994c). Furthermore, the only site potentially upgradient from a water supply well is the Camp Fogarty Disposal Area (Site 10) (TRC 1991, 1994c).
Some residents in the towns of North Kingstown and East Greenwich rely on private wells to supply water for drinking and domestic uses. Of the private wells identified in North Kingstown, eight wells are located northeast and upgradient of Sites/Study Areas 01, 02, 03, and 04 (Navy 1998c). No private wells in North Kingstown are located downgradient of NCBC, Davisville sites or study areas. The exact number and locations of private wells in East Greenwich have not been determined; therefore, we lack accurate information on whether private wells exist south and west, or downgradient, of the Camp Fogarty area (TRC 1991). Nevertheless, private wells in this area would draw from protected groundwater capture zones in the Potowomut-Wickford Aquifer and not the crystalline aquifer that underlies the Camp Fogarty area.
Nature and Extent of Groundwater Contamination
Groundwater contamination was detected at 12 sampled IRP Sites/Study Areas.(1) Only a small amount of contamination was detected in the groundwater at Sites 06, 08, 11, and 13. Sites 06, 08, 11, 13, and 16 are located downgradient of and/or away from public water supply wells and private wells. For these sites, the only chemicals (if any) that exceeded CVs by a significant amount were metals; in most cases metals that exceeded CVs were detected below background levels (EA 1998f).
Preliminary findings from recent investigations at Site 16 detected VOC contamination at depth in groundwater (EPA 1999f, Navy 2000a). The Navy has expanded their investigations to examine sediment and groundwater in the deep bedrock beneath Site 16. The EPA recommends further investigations of Building 41 for potential sources of groundwater contamination. Building 41, located southwest of Site 16, is believed to have been used for degreasing and metal preservation (Navy 2000a; EA 2000a, EA 2000b).
Groundwater contamination at the Camp Fogarty Disposal area (Site 10); Calf Pasture Point (Site 07) and Allen Harbor Landfill (Site 09); and Sites/Study Areas 01, 02, 03, 04, and the Nike Battery Site are discussed in more detail below.
Camp Fogarty Disposal Area (Site 10)
Camp Fogarty (Site 10), located in the town of East Greenwich, is currently owned by the Army and assigned to the Rhode Island National Guard. Groundwater samples were collected at the Camp Fogarty Disposal area during the Phase I and Phase II remedial investigations. During Phase II, groundwater sampling used a low flow sampling technique considered to be more representative of Camp Fogarty Disposal area contaminant concentrations than concentrations detected during Phase I. Levels of arsenic, chromium, lead, and manganese in the groundwater at Camp Fogarty were detected above ATSDR CVs for drinking water. All of these metals, except lead, were detected below established background levels for NCBC, Davisville (EA 1998f) and are not site-related contamination. During Phase I, lead was detected at 140 parts per billion (ppb), above EPA's action level of 15 ppb. However, only one Phase II sample exceeded the EPA's action level for lead (detected at 16.5 ppb). Debris, a potential source of groundwater contamination at Site 10, was removed in late 1996 and disposed of off site. A no further action ROD was issued in June 1998 for both soil and groundwater at Site 10.
Regional groundwater flow in the vicinity of NCBC, Davisville shows that the Camp Fogarty Disposal area is the only IRP site potentially upgradient of a public water supply well (TRC 1991, 1994c). The public drinking water well closest to Site 10 is approximately 1 mile away, and the well's wellhead protection area and groundwater capture zone do not encompass Site 10 (TRC 1991, 1994c). No private drinking water wells lie downgradient of Camp Fogarty.
Calf Pasture Point (Site 07) and Allen Harbor Landfill (Site 09)
The two areas with the most groundwater contamination at NCBC, Davisville are Calf Pasture Point (Site 07) and Allen Harbor Landfill (Site 09). At Calf Pasture Point, VOC plumes have been identified in the shallow, deep, and bedrock hydrogeological zones. The major contaminants in these plumes include 1,2-dichloroethene, 1,1,2,2-tetrachloroethane, and trichloroethylene (TCE). The source of the plumes appears to be a former trench at Calf Pasture Point that was used to dispose of 3-gallon cans of decontaminating agent non-corrosive solution. Elevated levels of metals have also been detected at Calf Pasture Point. These metals are not present in plumes and no source has been identified. In general, groundwater at Calf Pasture Point flows toward Allen Harbor or Narragansett Bay (EA 1998d).
Under the Allen Harbor Landfill, groundwater contamination is present in numerous areas; however, specific plumes have not been identified. Metals, VOCs, semi-volatile organic compound (SVOCs), dieldrin, 4,4'-DDD and, PCBs have all been detected above CVs (Tables 2 and 4). In general, groundwater in the vicinity of the landfill flows towards Allen Harbor. Some of the shallow groundwater also flows west toward Sanford Road (EA 1996). The Navy will continue long-term groundwater monitoring following the transfer of the site to the town of North Kingstown.
Sites/Study Areas 01, 02, 03, and 04, and the Nike Battery Site
Sampling data from 1995, 1996, and 1998 revealed elevated levels of VOCs in both the deep and bedrock aquifers beneath NCBC, Davisville. VOCs, including TCE (up to 6,800 ppb) and vinyl chloride (up to 5 ppb), found in the deep aquifer exceed their respective ATSDR CV or EPA MCL of 5 ppb for TCE and 0.02 ppb for vinyl chloride. Similarly elevated levels of TCE ( up to 3,400 ppb) and vinyl chloride (up to 17 ppb) have been detected in the bedrock aquifer (EA 1998f). VOC concentrations decrease with distance from western boundary of this area.
The Phase II remedial investigation for NCBC, Davisville found that the concentrations of VOCs in the groundwater at the off-site Nike Battery Site upgradient and west of Sites 02 and 03 were even higher than the levels detected underneath the two sites. In 1955, the U.S. Army Corps of Engineers (USACE) built a Nike Missile battery (three underground missile silos) at this site for missile assembly, testing, and launch. The site was deactivated in 1962, and the RIEDC currently owns the area. The Nike Battery Site has been investigated by the USACE under the Formerly Used Defense Sites program (EA 1998f). In general, groundwater from the Nike Battery Site flows easterly toward NCBC, Davisville property, near Sites/Study Areas 01, 02, 03, and 04.
The Navy's Phase III Comprehensive RI Report for Sites/Study Areas 01, 02, 03, and 04 included an investigation of the former Nike Battery Site. It was determined that the major subsurface source of the VOC plume extending under Navy property (including Site/Study Areas 01, 02, 03, and 04) was located in the deep groundwater zone just east of the missile silos at the Nike Battery Site. Navy groundwater investigations have also identified three other minor source areas beneath the Navy property, as well as lead and arsenic contamination not attributed to the Nike facility.
VOCs were also found in some of the monitoring wells located north of the Nike missile silos (Table 5). In response to this finding, seven of the private wells in this area were tested on May 6, 1997. The monitoring detected the VOCs tetrachloroethylene (0.7 ppb) and 1,1,1-trichloroethane (1 ppb) in samples collected from one private well, but at levels below CVs. No other VOCs were detected in any of the tested private wells (Navy 1998c).
The Navy continues to characterize the nature and extent of the VOC plume in the bedrock aquifer at property overseen by the Navy, including Sites/Study Areas 01, 02, 03, and 04 (USACE 1999). Although the extent of the VOC plume in the bedrock aquifer has not been fully characterized, it is believed that the direction of groundwater flow in that aquifer is from the Nike Battery Site easterly towards NCBC, Davisville (EA 1998f).
The USACE continues to investigate the off-site plume associated with the Nike facility. The EPA recommends the Navy initiate interim remedial actions (e.g., monitoring and groundwater use restrictions) on their property after the USACE completes a plan to control the off-site plume (EA 2000b; EPA 2000c, 2000d). The Navy will eventually transfer the property after the remedy for the off-site plume originating at the Nike battery Site is operating properly and successfully. Following the transfer, the Navy will continue to monitor groundwater through a long-term monitoring program. Institutional controls will be in place to restrict the use of groundwater as a source of drinking water.
Evaluation of Potential Public Health Hazards
Sites 06, 08, 11, 13, and 16 are all downgradient of public water supply wells and therefore do not pose a past, current, or future health hazard. Camp Fogarty Disposal area (Site 10) is potentially upgradient of a public water supply well. The groundwater at Camp Fogarty is not considered a past, current, or future health hazard, however, because (1) the few contaminants that exceeded CVs--except lead--were detected below background levels, (2) Phase II data showed that the maximum detected concentration for lead was only slightly above the CV, (3) the closest public water supply well is located approximately 1 mile away, and (4) the well's wellhead protection area and groundwater capture zone do not contain Site 10.
No public water supply wells are located downgradient of Calf Pasture Point and Allen Harbor Landfill so there is no past or current completed exposure pathway. The RODs for both of these sites include deed restrictions to prevent human exposure to contaminated groundwater since groundwater will not be directly remediated at either site (EA 1997a, 1999b). As long as these restrictions are in place, there will be no future exposure to contaminated groundwater at these sites.
Investigations of the VOC plume under the Nike Battery Site and NCBC, Davisville are ongoing. The USACE, the lead agency for investigations at non-Navy property, is investigating conditions at Nike Battery Site and residential property to the northeast. (The Navy has and continues to provide the USACE with groundwater data for downgradient Navy property.) The residential well sampling done north of the Nike Battery Site and Navy property showed that only one residential well contained VOC contamination--but at levels well below ATSDR CVs. Drinking water from this well should not cause ill health. ATSDR supports continued investigations with special focus on determining the likelihood of further private well contamination in the future.
No public water supply wells or private wells are currently located in or downgradient from the VOC contamination at the Navy property; therefore, no exposures to VOCs in groundwater have occurred in the past or are occurring now. Navy-owned property affected by the plume will be transferred in the future. Exposure of future owners, occupants, or workers to potentially unhealthy levels of contaminants should be prevented through remediation of source areas and institutional controls to restrict the use of groundwater as a source of drinking water. ATSDR concludes that groundwater contamination at NCBC, Davisville poses no past or current public health hazards. No public health hazards are likely to occur in the future as long as the VOC-contaminated groundwater is not used.
Evaluation of Soil Exposure Pathway
Nature and Extent of Soil Contamination
Soil samples collected from every site and study area at NCBC, Davisville contained contaminants, including metals, SVOCs, VOCs, and pesticides/PCBs, at levels above CVs. In most cases, these levels were only slightly above CVs(2). Arsenic was detected above its CV at almost every site. For all sites--except for Allen Harbor Landfill--the maximum detected concentration of arsenic was below the maximum background concentration of 8.1 ppm (TRC 1994c). In a few cases, chemicals were detected in areas at levels that exceeded CVs by more significant amounts; these areas are discussed below.
Building 56 (Study Area 15)
Building 56 (Study Area 15) was located in a supply area in the Administrative Triangle portion of the Main Center of NCBC, Davisville; hazardous materials were used and stored there (Navy 1994). Former barracks are located at least 900 feet away from the area and two softball fields are located at least 1,200 feet away from the area (EA 1998a; EPA 1999e). Investigations at Building 56 detected elevated levels of lead in the soil near the building. The suspected source of the contamination was lead-based paint on the building. Two samples taken 2 and 5 feet from the building contained lead levels of 2,600 ppm and 510 ppm, respectively. All other samples taken near the building contained lead at levels below EPA's interim guidance level of 400 ppm (EA 1998c). The building was demolished and surrounding soil (up to six inches below grade) was removed in 1997. Follow-up sampling confirmed that the elevated lead soil contamination had been removed to levels of 89 ppm (EA 1998c).
Waste Disposal Area North of Buildings W-3 and W-4 (Site 13)
The Waste Disposal Area north of Buildings W-3 and W-4 (Site 13) is a grassy field that was used to dispose of waste oils. The site is located in the warehouse area of the Main Center at NCBC, Davisville. During the Phase I RI, the highest detected soil concentration of PCB-1260 was 12,000 ppm (detected in 2 of 10 samples). During the Phase II RI, the maximum detected concentration of PCB-1260 was 0.6 ppm (detected in 17 of 34 samples). Only 2 of the 17 Phase II detections (12%) exceeded the CV for PCBs. Furthermore, a Phase II sample collected less than 60 feet away from the location of the maximum Phase I concentrations did not contain detectable levels of PCB-1260.
Allen Harbor Landfill (Site 09)
Allen Harbor Landfill (Site 09) was used for the disposal of NCBC, Davisville and NAS Quonset Point wastes. Wastes included municipal-type waste, asbestos, construction debris, sewage sludge, rubble, PCB oil, paint thinners, degreasers, preservatives, ash, and waste fuel oil. A number of chemicals have been detected above soil CVs: arsenic, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, cadmium, copper, dibenzo(a,h)anthracene, indeno(1,2,3-cd)pyrene, iron, lead, and PCBs.
Evaluation of Potential Public Health Hazards
Lead-contaminated soil at Building 56 was localized; lead levels beyond 5 feet from the building were below EPA's interim guidance level. Furthermore, the building was located in a supply area several hundred feet from both the former barracks and two softball fields. Because of the localized area of contamination and the distance that existed between the site and the barracks/fields it is unlikely that lead-contaminated soil represents a past public health hazard to recreational users of the fields or barrack residents. In 1997, Building 56 was demolished and the lead-contaminated soil was removed from the area (EA 1998c), therefore, no current or future exposure pathways exist.
PCB-contaminated soil at Waste Disposal Area north of Buildings W-3 and W-4 (Site 13) did not pose a health hazard in the past because the site is located in a warehouse area where people are not known to frequent. Moreover, the contamination appeared to be localized. PCB-contaminated soil was removed from Site 13 in 1996 and 1997 and the area was backfilled with clean fill and seeded. The excavated contaminated soil was disposed of at an off-base location (Navy 2000a). A No Further Action ROD for soil at this site was issued in September 1998. Therefore, there is no current or future exposure to PCB-contaminated soil.
Remediation of the Allen Harbor Landfill (Site 09), which includes a landfill cap, is complete (EA 1999a, Navy 2000a). Recently discovered PCB-contaminated soil at the site was removed and disposed of at an off-base location (Navy 2000a). Exposure to contaminated soil at Allen Harbor Landfill was not likely to occur in the past, nor is it likely to occur now, due to restricted access at the site. The transfer of the land to the town of North Kingstown includes deed restrictions that will prohibit certain uses (e.g., no digging and no dirt biking) that could disturb the landfill cap. A fence will demarcate the area of deed restrictions and signs will be posted to limit access to pedestrian traffic only. These measures should be sufficient to prevent future exposure to any contaminants in the soil.(3)
ATSDR concludes that exposure to contaminated soils at NCBC, Davisville has been minimal, if it occurs at all, and therefore on-site surface soil poses no past, current, or future health hazards.
Evaluation of Surface Water/Sediment Pathway
Nature and Extent of Surface Water/Sediment Contamination
The Navy collected sediment and surface water samples from several Allen Harbor shoreline areas and from streams and ponds in the NCBC, Davisville vicinity. Few chemicals (e.g., metals) in sediment and surface water were detected at levels that exceeded CVs, and then by less than an order of magnitude. Table 2 contains site-specific surface water and sediment sampling results.
The Navy investigated the potential for shallow groundwater near the shore at Allen Harbor Landfill (Site 09) to leach chlorinated VOCs into Allen Harbor. Detected organic contaminants in Site 09 shallow groundwater include tetrachloroethene detected up to 670 ppb and TCE detected up to 74 ppb (see Table 4) (EA 1997a). Largely due to natural biodegradation, chlorinated VOCs and other contaminants detected in shallow groundwater underlying Site 9 are unlikely to discharge into Allen Harbor in the future (TRC 1993).
Evaluation of Potential Public Health Hazards
No one drinks local surface waters. Streams and ponds at or near NCBC, Davisville do not support swimming (they are either too shallow or not accessible). During its August 1999 site visit, ATSDR observed swimmers at the entrance channel to Allen Harbor. People also swim periodically along shoreline beaches in the NCBC, Davisville vicinity. No signs are posted to prevent or deter swimmers. Due to the infrequent use of the area for swimming purposes, exposure to the few chemicals detected in Allen Harbor surface water and sediment likely occurs infrequently and for short durations. Limited dermal contact and incidental ingestion exposure to the low levels of contaminants detected is not expected to cause adverse health effects. Given the low levels of contaminants currently detected, ATSDR believes it is safe to periodically swim in the NCBC, Davisville vicinity. If local surface water and sediment quality degrades in the future, ATSDR may reassess its conclusion. However, future water quality degradation appears unlikely due to the natural biodegradation of detected contaminants. Based on current available information, ATSDR concludes that surface water/sediment in and around NCBC, Davisville poses no past, current, or future health hazards.
Evaluation of Food Chain Exposure Pathway
Consumption of Shellfish and fish
Shellfishing in Allen Harbor was banned in 1984 because of bacteriological contamination. Chemical contamination from several sources, including the Allen Harbor Landfill, was also suspected (EA 1997b). Data were collected in 1991 and confirmed chemical contamination in shellfish (ATSDR 1995). The current ban on shellfish harvesting activities at the Harbor reduces public health hazards by deterring consumption of potentially contaminated shellfish. Although it is impossible to conclusively state that no one is trespassing and violating the ban, signs are posted to inform people of the ban in the area.
In October 1995, ATSDR released a health consultation for NCBC, Davisville (ATSDR 1995). Based on 1991 chemical contaminant data for shellfish from Allen Harbor, ATSDR concluded that citizens should be advised not to consume oysters harvested from areas abutting the landfill if the harbor is ever reopened for shellfishing; however, other shellfish could be consumed. ATSDR also stated that women who are pregnant or are planning to become pregnant should not consume quahogs (hard-shell clams) or soft-shell clams from Allen Harbor. ATSDR recommended limits (as consumption rates) for shellfish consumption in the event that the harbor is reopened. Based on the data and analyses in this health consultation, ATSDR is classifying shellfish consumption prior to the 1984 shellfishing ban as a public health hazard.
In addition to the 1991 samples, shellfish, including hard-shelled clams, soft-shelled clams, and oysters, were sampled for chemical contamination in the mid-1990s. These samples were taken to see whether and to what extent site-related contaminants have affected shellfish in Allen Harbor (especially in areas near Sites 07 and 09). In the discussion that follows, ATSDR summarizes whether shellfishing in this area would pose a public health hazard if the ban were not in place. Uncleaned shellfish samples were excluded from the evaluation because it is assumed that people rinsed and/or soaked shellfish before consumption. Also, ribbed mussel samples were excluded since they are not generally eaten due to their unpleasant taste. Since ATSDR does not have shellfish tissue CVs, maximum contaminant concentrations detected in the samples were compared to EPA Region III Risk-Based Concentration (RBC) values.(4) Contaminants detected below EPA's RBCs were not analyzed further.
Table 6 presents the results of the shellfish sampling in the mid-1990s. As the table indicates, metals, polycyclic aromatic hydrocarbons (PAHs) (as benzo(a)pyrene), and PCBs have been detected in shellfish harvested from the harbor at levels above EPA's RBC. Lead was also detected in a few samples, but an RBC currently does not exist for this metal.
In evaluating potential health hazards from eating shellfish from the harbor containing these chemical contaminants, ATSDR calculated exposure doses for people who consume average amounts of fish (about 8 ounces for an adult and 4 ounces for a child per month) using contaminants detected above EPA's RBCs and lead (no RBC available). ATSDR has very limited information concerning who harvested the shellfish along the harbor. Anyone harvesting shellfish in the past could have gained access to the harbor through Navy-owned property, North Kingstown-owned property, or by boat (Navy 2000b). Exposure doses were calculated based on conservative assumptions for ingestion rates and exposure frequencies (see Appendix C).
ATSDR compared the estimated doses with available health guidelines (such as ATSDR's minimal risk levels [MRL] and EPA's reference doses), cancer guidelines, and data from available toxicologic studies. (The health guidelines provide a conservative estimate of daily exposures to a chemical that are not likely to result in adverse health effects, even for the most sensitive members of a community [e.g., pregnant women, nursing mothers, children]).
Based on this analysis, ATSDR found that consumption of chemically-contaminated shellfish could pose an increased risk of adverse health effects, even for people consuming average amounts of shellfish (about 8 ounces for an adult and 4 ounces for a child per month) harvested from Allen Harbor, primarily because of concerns about methylmercury levels in the shellfish. Mercury in shellfish and fish exists primarily as the organic form methylmercury. The doses for adult and child exposures to mercury exceed the corresponding ATSDR MRL (for methylmercury), suggesting that exposure could result in harmful effects. Exposure to high levels of methylmercury in fish has been associated with an increased risk of developing mercury-related adverse health effects such as neurological problems (EPA 2000e). The developing fetus and young children are also particularly sensitive to the effects of methylmercury because it can cause damage to the developing nervous system. Signs and symptoms of neurotoxicity in adults and children may include difficulty with peripheral vision or blindness, sensory disturbances, incoordination, impairment of walking, and slurred speech (EPA 1999g). Persons consuming more than average amounts of shellfish, such as subsistence fishermen or Native Americans, may have been exposed to higher doses of mercury. Based on these findings, ATSDR supports the current shellfishing ban at Allen Harbor.
Remedial measures including a landfill cap should help prevent future contamination of shellfish in the harbor. Most importantly, the ban is in place to prevent public exposure to these contaminants now and in the future. Still, despite the ban, however, anecdotal information suggests that certain ethnic groups from the urban areas are coming to the harbor for grass shrimp harvesting (RIDOH 2000). If people are consuming grass shrimp, then EPA and/or the Navy should also consider sampling this shellfish for contaminant uptake.
ATSDR recommends that edible fish in Allen Harbor also be sampled. Currently, there is no ban or restriction on fish consumption. Unlike other contaminants, mercury is found primarily in the edible portion (muscle) of most adult fish (EPA 1999g). Therefore, special food preparation methods, such as skinning or trimming the fish, will not reduce the amount of contaminants in a fish meal. In fact, cooking the fish may increase the concentration because of moisture loss (EPA 1999g).
ATSDR recognizes that infants and children may be more sensitive to exposures than adults in communities faced with contamination of 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. For example, children may come into contact with and ingest soil particles at higher rates than do adults; also some children with a behavior trait known as "pica" are more likely than others to ingest soil and other nonfood items. Children are shorter than adults, which means they can breathe dust, soil, and any vapors close to the ground. Also, they 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. Because children depend completely on adults for risk identification and management decisions, ATSDR is committed to evaluating their special interests at sites such as NCBC, Davisville, as part of the ATSDR Child Health Initiative.
ATSDR has attempted to identify populations of children in the vicinity of NCBC, Davisville and any completed exposure pathways to these children. Children could have been exposed to harmful levels of methylmercury if they ate shellfish harvested from Allen Harbor. The developing fetus is at greater risk from methylmercury exposure than are adults. Infants may be exposed to methylmercury though breast milk. Children are considered to be at increased risk of methylmercury exposure by virtue of their greater food consumption as a percentage of body weight and because they may have a more difficult time eliminating mercy from their bodies (EPA 1999g). As stated, children are best protected from potentially harmful exposures to mercury by adhering to the ban and avoiding consumption of shellfish from Allen Harbor. This exposure pathway is discussed in greater detail in the previous section on the evaluation of environmental contamination and potential exposure pathways.
ATSDR did not find any other harmful exposures at NCBC, Davisville that are specific to children. Children do not have access to most contaminated areas and contaminated media are not located near the former family housing area where children lived and played. In addition, the two softball fields at NCBC, Davisville used by the town of North Kingstown are located at least 1,200 feet from the closest known contaminated area which has been remediated. Exposure to contaminated sediment and surface water is minimal. There is no swimming in local streams and ponds and infrequent swimming in the Allen Harbor vicinity. None of the drinking water supplied to NCBC, Davisville or the surrounding areas has been contaminated by NCBC, Davisville (information on the former Nike Battery Site has been provided in previous sections).
A Technical Review Committee (TRC) was established in 1988 by the Navy to provide direction for the IRP at NCBC, Davisville. The public began participating in TRC meetings in mid-1993. The TRC eventually became a subcommittee of the Restoration Advisory Board (RAB). The RAB holds bimonthly meetings open to the public that serve to promote community awareness and understanding of NCBC, Davisville environmental investigations (EA 1997b).
Community interest and involvement at NCBC, Davisville has generally been low since the initial investigation results were released in 1984. However, ATSDR did identify some community concerns, although some did not involve issues of public health. For example, residents asked about the future implications of redevelopment plans and land use restrictions to the local community. Other concerns addressed the process, implications, and use of an ATSDR public health assessment.
Through conversations with community members, review of the Navy's 1997 Community Relations Plan, and participation in the NCBC, Davisville RAB meetings, ATSDR identified several community concerns that involved issues of public health. Specifically, ATSDR found that the community had health concerns about groundwater contamination, Allen Harbor, a Navy Yacht Club Area, the former Camp Avenue Dump, Calf Pasture Point, and local incidences of cancer.
The public comment period for this document was held from October 13 through November 13, 2000. A newspaper article on the public comment version was printed by the North East Independent on November 9, 2000 (NE Independent 2000). The article listed ATSDR contact information. During the public comment period, no comments from the general public were received. Additionally, the status of the ATSDR public health assessment work was announced to the RAB during their regularly scheduled meetings.
Could underlying contaminated groundwater result in adverse human health effects for residents of neighboring communities or for former residents, employees, or visitors of NCBC, Davisville? Have the Navy's contaminant plume investigations and monitoring efforts of local private wells been sufficient to ensure the safety of public health?
Ongoing investigations continue to characterize the extent and nature of groundwater plumes in the Nike Battery Site and NCBC, Davisville vicinity. Based on available data, however, ATSDR concluded that groundwater at NCBC, Davisville is unlikely to pose a public health hazard. Public water supply wells are located upgradient (north and west) of the plumes and meet all state and federal drinking water standards. Residential well sampling in the town of North Kingstown indicates that private wells have not been impacted by harmful levels of site-related contaminants. ATSDR supports USACE in their continuation of investigations with special focus on determining the likelihood of private well contamination in the future from the former Nike Battery Site. We support the proposed measures, such as source remediation and land use restrictions, that will prevent future exposure to contaminated groundwater beneath the former Nike Battery Site and the Navy property. ATSDR also recommends that the Navy provide future land owners with information on the locations of contaminated groundwater at NCBC-Davisville. In particular, the Navy should make future owners of Sites/Study Areas 01, 02, 03, and 04 aware of the deep VOC contamination that has migrated to these sites from the Nike Battery Site (non-Navy) property. Future owners should also know that new wells installed at these sites could accelerate the movement of contamination from the Nike Battery Site. We will review additional data as they become available. For a more detailed review of ATSDR's analysis and findings, see the Evaluation of Groundwater Exposure Pathway section of this report.
How safe is Allen Harbor for boaters? Is it safe to go fishing/shellfishing and to consume locally-caught fish/shellfish?
Exposure to Allen Harbor surface water and sediment is expected to be minimal during boating and fishing activities, so ATSDR concluded that there are no past, current, or potential future health hazards for local residents from such recreational activities. No restrictions currently exist to deter local swimming because contaminant concentrations in surface water will not cause ill health (EA 1996). ATSDR concludes that shellfish are not safe to eat and that edible fish need to be sampled for mercury and other contaminants. Although the original ban was based on concerns about bacteriological contamination, ATSDR supports the Allen Harbor shellfishing ban (due to findings of chemical contamination) and advises people to adhere to it. Given the presence of elevated levels of chemical contaminants in shellfish, past consumption of locally-caught shellfish (prior to the 1984 shellfishing ban in Allen Harbor) could have adversely impacted human health. Anecdotal information suggest that grass shrimp from the harbor may be harvested for consumption. EPA and/or the Navy should consider sampling grass shrimp for contamination if indeed people are consuming this shellfish. The EPA has recently sampled tissue from fish collected from the Harbor as part of a nationwide survey. The results of the sampling, which are anticipated in mid-2001, will help determine whether any further actions (e.g., sampling, consumption restrictions) are needed in regards to the harbor fish population. For a more detailed review of ATSDR's analysis and findings, see the Evaluation of Surface Water/Sediment Contamination, Evaluation of Food Chain Exposure Pathway, and Appendix C sections of this report.
How safe is the Yacht Club area for boaters and fishermen? Is it safe to go fishing and to consume fish caught in the area?
ATSDR observed people fishing off of their boats in the Yacht Club area. No signs are posted to deter people from fishing and no fish or shellfish advisories currently exist in this vicinity (the Allen Harbor shellfishing ban does not extend to the Yacht Club area) (Navy 2000c). To date, no edible fish tissue samples from the Yacht Club area or other areas in Allen Harbor have been analyzed for chemical contaminants. Available ecological quality information indicates that water and sediment contaminant levels in the Yacht Club area are unlikely to contaminate fish (ERLN 1993). However, fish could migrate to contaminated areas and then to the Yacht Club area. ATSDR recommends that edible fish in Allen Harbor be sampled by RIDEM and RIDOH. ATSDR believes that the Yacht Club area is safe for boaters but does not know if local fish are safe for human consumption.
Persons interested in reducing exposures to contaminants in fish can find useful information,
including a list of Rhode Island's fish advisories, on the RIDOH web site at www.doh.state.ri.us .
A shellfish closure map for Rhode Island, based on bacteriological contamination, can be found
at the RIDEM website www.state.ri.us/dem/shellchz.htm . Additional information can be found
at EPA's website at http://www.epa.gov/ost/fish . This website lists a statewide advisory for Rhode Island coastal waters due to PCB contamination.
Does the former Camp Avenue Dump pose a public health hazard for students of the nearby elementary school?
No. NCBC, Davisville investigation sites or areas of concern lie in the former Camp Avenue Dump area. The Navy did not identify any potentially harmful debris or evidence of contamination in this part of the former Quonset Point base. ATSDR concludes that the former Camp Avenue Dump poses no public health hazard for local students.
Will future use and deed restrictions in the Calf Pasture Point area be protective of public health?
Future use and deed restrictions in the Calf Pasture Point area (Site 07) will protect public health, provided that the town of North Kingstown abide by the future use and deed restrictions. Use restrictions include the prohibition of well drilling and groundwater use. In the finalized Record of Decision for this site, the Navy determined that Calf Pasture Point will become conservation land with a limited potential for recreational development (EA 1999d). Under this scenario, soil and surface water are not a public health concern because contaminant concentrations in these media are below ATSDR comparison values and/or exposure to the contamination is infrequent and of short duration. Similarly, groundwater at Calf Pasture Point will not be used as potable drinking water in the future (it is saline and has a low recharge rate), so there will be no future exposure to underlying groundwater plumes. Public exposure to contaminants from the ingestion of local shellfish will continue to be prohibited by the Allen Harbor shellfishing ban (EA 1999d).
Will it be safe to access the Allen Harbor Landfill in the future?
We do not expect that the public will come in contact with waste in the Allen Harbor Landfill. As part of the remediation efforts, a protective cap was added to the landfill. The cap prevents the exposure of the public to materials or contaminants within the landfill. As long as the cap on the landfill is undisturbed, we do not anticipate any public exposure to the materials contained within the landfill in the future. Additionally, use restrictions (e.g., no digging and dirt biking) are in place to limit activities that could threaten the integrity of landfill cap. A fence and posted signs will help limit access to pedestrian traffic only.
Landfills can emit gases, such as methane, created from decomposing waste. The landfill will be vented and the Navy will routinely sample the offgas at the vents for methane and hydrocarbons. Because of the age of the landfill, we anticipate that the landfill will generate just small amounts of gas, if any. The Navy will control and treat gases exceeding air quality requirements to reduce potential safety and health hazards.
Have any health studies been done in the NCBC, Davisville vicinity and are there elevated incidences of cancer in the local communities?
Based on the contaminants present in the local environment and on the estimated levels of public exposure, there is no risk for increased cancer incidences. For a more detailed review of ATSDR's analysis and findings, see the Appendix C section of this report. We are not aware of any health studies for the Davisville vicinity. If site-related data become available that indicate an increased risk for cancer, ATSDR will review any pertinent available local health studies.
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