PUBLIC HEALTH ASSESSMENT
Elizabeth Copper Mine
(a/k/a Elizabeth Mine)
Strafford, Orange County, Vermont
CERCLIS NO. VTD988366621
August 23, 2004
The Vermont Agency of Natural Resources (VTANR) started investigating the site in 1991. Since then, the Environmental Protection Agency (EPA), VTANR, and the U.S. Geological Survey (USGS) have sampled and tested private drinking water wells, groundwater, surface soil, surface water, sediments, ambient air, residential dust (bulk and wipe), and/or biota (fish) to identify possible site-related contamination. Sampling data identified metals and/or organics in each of these media. EPA identified acid mine drainage as a source of contamination and, in March 2002, released a Proposed Plan outlining remedial action alternatives for controlling the release of acid mine drainage. The EPA is also performing additional investigations of site contamination and is in the process of completing a Remedial Investigation (RI) for the site.
In 2000, the Agency for Toxic Substances and Disease Registry (ATSDR) received petition letters from community members concerned about possible health effects associated with exposures to site-related contaminants. In 2000, EPA also requested that ATSDR review soil sampling data collected near the site. To address the community concerns and the EPA request, ATSDR produced three health consultations examining exposure to drinking water from private wells, contacting on-site and residential soil, and inhaling airborne contaminants; the box on page 3 and Appendix C summarizes conclusions from these health consultations.
In this public health assessment (PHA), ATSDR evaluated additional site-related data that were gathered after the release of the health consultations and exposure pathways that were outside the scope of those documents, including:
- Drinking water from residential wells in the vicinity of the site.
- Using streams and surrounding areas for recreational purposes.
- Consuming fish caught in rivers downstream of the site.
After reviewing and evaluating all the available data pertaining to private drinking water well, surface water, sediment, and biota data for this PHA and reviewing the evaluations of on-site and residential surface soil, dust, and air data for the health consultations, ATSDR determined that no harmful exposures currently exist at the Elizabeth Mine site. Past exposure to metals in a single private well, however, may have resulted in adverse health effects if chronic exposures occurred. This well has been closed to prevent chronic exposures. Because possible past health hazards related to exposures to the contaminants from the one well were addressed and existing contamination is below levels of concern according to an evaluation of possible exposure scenarios, ATSDR characterizes the Elizabeth Mine site as posing no apparent public health hazard. (See Appendix F for definitions of the different conclusion categories).
ATSDR classifies current and future exposures at the site as posing no apparent public health hazard. This classification is based on the assessment of available private well, surface soil, dust, surface water, sediment, air, and biota (fish) sampling data. And reflects EPA's planned cleanup actions. Sampling identified metals and/or organics in each of these media, above ATSDR's health-based comparison values (CVs), except for fish. As a result, ATSDR reviewed available data and considered plausible exposure scenarios and chemical toxicities and found that exposures are not expected to cause illness or adverse health effects. ATSDR recommended that children be discouraged from playing on the tailings piles located onsite. ATSDR also recommended monitoring blood lead levels in children under 6 years of age as a preventative measure. Lead was found in two bulk dust samples from one home at 430 and 1,600 parts per million (ppm). These levels exceed the EPA screening level for lead in surface soil (400 ppm). ATSDR evaluated the data for children exposed to these levels of lead in dust in a 2001 health consultation. ATSDR concluded that routine exposure to the highest lead levels could cause adverse health effects for children; however, the elevated lead detections did not appear to be representative of overall lead levels in that home. Therefore, blood lead level monitoring in children living in this home was recommended based on the best available public health practices. ATSDR will continue to review the newest data for the Elizabeth Mine site as they become available and will issue new documents to address the community concerns listed above as well as other community concerns that may be expressed as part of the public comment period of the PHA process. The EPA is in the process of releasing a Remedial Investigation that will contain a great amount of data for ATSDR to review and will enable ATSDR to prepare future documents for the Elizabeth Mine community.
ATSDR characterized past exposures at the Elizabeth Mine site as posing a public health hazard because sampling data detected concentrations of aluminum, cadmium, copper, manganese, and iron in one private well. ATSDR concluded that prolonged daily consumption of water from residential well #3 could pose a public health hazard on the basis of exposure to the maximum detected concentrations of aluminum, cadmium, and copper. The residence served by the well experienced problems with septic system contamination. The land owner assisted the resident in finding alternate housing and also removed the trailer home from the property prior to ATSDR's recommendation to close well #3. In assessing past exposures to metals and/or organics found in surface soil, dust, surface water, sediment, air, and biota, ATSDR considered available site data as representative of past exposures because no actions were taken to remove contaminants from these media before sampling was conducted. Although sampling found metals and/or organics above CVs in each of these media, except fish, a review of possible exposures and chemical toxicities found that exposures would not be expected to cause illness or adverse health effects.
| Summary of ATSDR's Health Consultations |
During 2000 and 2001, ATSDR released three health consultations on the Elizabeth Copper Mine.
Health Consultation: An Evaluation of Residential Drinking Water Wells Adjacent to the Elizabeth Copper Mine Site, Strafford, Orange County, Vermont. October 24, 2000.
ATSDR completed three health consultations in 2000 and 2001 to address community concerns about drinking water from private wells, contacting soil impacted by mining activities, and breathing dust and air from the site. These health consultations are summarized in the box on page 3 and Appendix C. In preparing the PHA, ATSDR addressed specific community health concerns. ATSDR re-evaluated potential exposures to drinking water from private wells using additional data and considered whether site contamination could be responsible for a number of adverse health effects community members experienced, such as seizures, epilepsy, respiratory and digestive problems, skin irritation, and kidney problems. ATSDR also evaluated site conditions and available environmental data to identify other potential exposure pathways, including contacting on-site surface soil during trespassing, contacting surface water and sediment during recreational activities, and consuming fish caught in downstream water bodies. In determining whether adverse health effects are possible, ATSDR considered plausible exposure scenarios, environmental data, chemical toxicity information, and remedial actions planned to reduce, prevent, or further investigate possible exposures. This PHA evaluates additional site-related data that were gathered after the release of the health consultations (drinking water) or exposure pathways that were outside of the scope of the health consultations (surface water, sediment, and biota).
- Site Description and History
The Elizabeth Mine site is located in the towns of Strafford and Thetford in east-central Vermont, approximately 1.9 miles southeast of the village of South Strafford, on the eastern flank of Copperas Hill. The site is approximately 15 miles north of White River Junction, and 9 miles west of the Connecticut River (Appendix A, Figure 1) (EPA 2002). Old Mine Road runs to the northwest from the northern tip of the Elizabeth Mine site. Three families live on Old Mine Road, a dirt road located adjacent to and to the west of the site. The closest home is 150 feet from the northern boundary of the Elizabeth Mine site.
The site contains open pit mines (two open cuts), extensive underground workings (mine shafts and adits), three tailings areas, several buildings, and a satellite area (South Mine) with tailings and a shaft. Underground mines drain to surface water through the Air Vent, a 1-foot diameter iron pipe located south of the Ompompanoosuc River. Tailings Pile 1 (TP1, 30 acres) and Tailings Pile 2 (TP2, 2 acres) are located in the northeastern portion of the site. The tailings piles consist of fine-grained tailings from a flotation mill that operated on-site from 1943 to 1958 (USGS 2000). A local landowner previously covered parts of TP1 with 6 inches of topsoil in order to grow vegetation and reduce wind-blown dust. Some trees and sparse vegetation grew in those areas. Tailings Pile 3 (TP3, 6 acres), located in the southwestern corner of the site, consists of coarser mine spoils from earlier mining operations (USGS 2000); it has little vegetation except for a few small birch and white pine trees. All three tailings piles are within 0.5 mile of the nearest residences.
Most of the immediate area is barren, but dense trees grow nearby. Multiple small streams, some very wide and some very narrow, run through the site, along mine cuts or alongside steep hills of tailings piles. Copperas and Lords Brooks pass through the site and flow into the West Branch of the Ompompanoosuc River (WBOR) north of the site. Access to some portions of the site is restricted by a fence. An unpaved dirt road cuts across another portion of the site (TP3). The site is private property and the land owner has posted private property signs; however, EPA has not posted any additional signs. EPA has documented that loggers and recreational users (such as all-terrain vehicle riders) use the unpaved road (EPA 2003b).
Elizabeth Mine opened in 1793 when a large sulfide ore deposit was discovered southeast of South Strafford. Pyrrhotite (iron ore and iron sulfate) was mined to produce copperas. Copperas is used for sulfuric acid production, as a disinfectant and sheep dip, as an astringent medicine, as a drier in the manufacturing of ground pigment, and as blackening and coloring for leather. Large scale production of copperas began in 1810 and continued until the 1880s. Copper mining began in 1830, when the Strafford Copper Works was formed. Copper mining continued until 1930, when the mine closed temporarily. The mine remained closed until 1942, when it reopened to provide copper for World War II use. Most of the underground copper mining at the Elizabeth Mine site took place between 1942 and 1958, when the mine was closed permanently (EPA 2002).
Investigations to identify if the Elizabeth Mine site was a source of pollution to the West Branch of the Ompompanoosuc River (WBOR_ began in the 1970s. In 1999, the Vermont Department of Environmental Conservation (VTDEC) requested that the U.S. Environmental Protection Agency (EPA) assist in conducting additional assessments of the site (EPA 2002). In 2000, VTDEC and EPA conducted investigations and collected samples at the site. VTDEC and EPA collected drinking water, surface soil, air, and indoor dust and wipe samples from residential homes near the site on Old Mine Road. The U.S. Geological Survey (USGS) collected composite waste dump and tailings soil samples from the site. EPA collected surface water, sediment, and fish tissue samples in 2000 and 2001.
On the basis of the data obtained from analyzing the samples, EPA proposed a phased cleanup for the Elizabeth Mine site, that included early cleanup of the most obvious sources of contamination, followed by cleanup of remaining areas of contamination as identified by a planned remedial investigation and feasibility study (RI/FS). EPA began the RI/FS in 2000 and anticipates completion in 2003, depending on available funding. Additional groundwater sampling is proposed as part of the RI/FS (EPA 2003a). The RI/FS is intended to determine the need and scope of any additional cleanup actions. The early cleanup plan consists of diverting clean surface water and groundwater flow around the tailings piles, capturing and treating acid mine drainage flowing from one tailings pile and from the toe of another tailings pile using a combination of natural treatment systems, to preserve a portion (up to 100%) of the copper waste rock and copperas heap leaching piles adjacent to the North Open Cut, and covering two tailings piles with a cover system to limit infiltration (EPA 2002). Appendix C details the operational and regulatory history of the Elizabeth Mine site.
- Demographics and Land Use
Elizabeth Copper Mine is located in Orange County, along the Strafford-Thetford city line in east-central Vermont, near White River Junction and close to the Connecticut River. The mine site is surrounded by rural/industrial areas. Approximately 28,000 people live in Orange County (http://quickfacts.census.gov/qfd/states/50/50017.html). Census data indicate that 272 people live within a 1-mile radius of the site, Appendix A, Figure 2 provides additional information about area demographics.
ATSDR staff conducted a site visit in January 2004 to observe changes in the site conditions; however, the snowy conditions prevented access to the site during the visit. ATSDR staff and representatives from VTANR, VTDEC, and the Vermont Department of Health (VTDOH) conducted a site visit to document site conditions on October 24, 2001. Staff were able to observe that access to the site is restricted by a gate; however, there was evidence of all-terrain vehicle tracks on the site. Staff also noted bullet holes on some of the signs and several "No hunting" signs on TP3. Moose and deer tracks were observed around TP1. The DEC reported that local university students swim in the mine cut, which is full of water; ATSDR did not observe evidence of this activity during this visit. There are several dilapidated buildings on the site. At the top of the site there are two open-cut mines with steep drop-offs. There are several adits (horizontal mine openings) that lead to underground shafts.
Three tailing piles cover the majority of the site. TP3 is located close to the mine cuts, upgradient from the other two piles (TP1 and TP2). TP3 consists of remnants of mining operations from the 1800s through the early 1900s. Numerous mounds of red, brown, and yellow coarse mine tailings make up approximately 6 acres of TP3. TP1 and TP2 are from operations that occurred in the early to mid-1900s. TP2 is a 2-acre flat mound of finer grain, sandy-brown material located immediately below TP1. TP2 overlaps TP1, which forms the northeastern portion of the site and covers approximately 30 acres of the property. TP1 is covered by some vegetation, mostly grasses and small birch trees. The nearest residence is located approximately 150 yards from TP3. Other residents line Mine Road down to the town of Stafford.
Copperas and Lords Brooks originate beyond site boundaries and flow northerly through the site before discharging into the WBOR, north of the site. During the site visit, staff observed the confluence of Cooperas Book and the WBOR, approximately 3/4 mile north of the site. The Copperas Brook flows north and receives drainage from the site. At the time of the visit, the water was discolored. These brooks may be used for recreation, such as wading, by trespassers on the site; however, no evidence of this activity was identified during the site visit. Union Village Dam is located approximately 6 miles downstream of the mines. The WBOR merges with the Connecticut River 5 to 6 miles further downstream. The WBOR and Connecticut rivers are used for limited recreation (such as boating and fishing), although the weather in Vermont limits water-related recreation, as well as contact with surface water and sediment in these water bodies, to the warmer summer months. In January, February, and March, the average high temperature is below 30 degrees Fahrenheit (F). Only in the summer months (July and August) does the average high temperature exceed 75 F (Weather Underground 2003).
The town of Strafford has no local public water supply. Strafford residents rely on individual water supplies, such as springs and wells (dug or drilled). Approximately 1,400 people within 4 miles of the mine site rely on groundwater as a drinking water source. VTDEC identified nine private drinking water wells along Old Mine Road and within 0.5 mile of the mine and the mine tailings. The area that contained two private drinking water wells (residential wells #3 and #3A) is currently uninhabited. The wells are no longer used; however, it is not known whether the wells have been capped. The land owner assisted the resident in relocating from this home because of septic system problems occurring in 2000. The well locations are shown in Appendix A, Figure 3.
- ATSDR Involvement
In 2000 and 2001, ATSDR prepared and released three health consultations, assessing drinking water, residential soil, mine tailings, indoor air and dust (the box on page 3 and Appendix C provide more information). The first health consultation, An Evaluation of Residential Drinking Water Wells Adjacent to the Elizabeth Copper Mine Site (2000), reviews results of samples collected from nine private drinking wells between March and May 2000. Eight of these wells were used as drinking water sources and one well was located on an empty lot. Samples were analyzed for volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), polychlorinated biphenyls (PCBs), and metals. The sampling data reported aluminum, cadmium, chromium, cobalt, copper, iron, and manganese above health-based comparison values (CVs). ATSDR concluded that well #3 contained cadmium, copper, and aluminum at levels that could pose a public health hazard following prolonged daily consumption. Manganese and iron levels in well #3A were elevated, but this well was no longer active. The previous resident had problems with contamination in the septic system. The landowner assisted this resident in relocating and then removed the mobile home from the site.) Metal levels found in other wells (chromium in well #9 and manganese in wells #1, #3, #4 and #5) posed no hazard from prolonged daily consumption (ATSDR 2000a).
In 2000, EPA requested that ATSDR review the results of soil samples collected at three homes along Old Mine Road. ATSDR prepared a second health consultation, Residential Soil and Mine Tailings, Elizabeth Copper Mine Site, and evaluated the results from three surface soil samples collected from each of these homes, as well as USGS samples collected from the on-site tailings piles (ATSDR 2000b). Samples were analyzed for metals. Elevated levels of metals were found in residential yards and on site. After evaluating data, ATSDR identified no acute or chronic hazards from dermal exposure or ingestion of residential soil (ATSDR noted that data had not been validated and thus may be inaccurate). ATSDR also evaluated plausible on-site exposure scenarios, and concluded that direct exposure, including exposure via ingestion and dermal contact, to metals in the on-site tailings piles was not expected to result in adverse health effects.
In 2001, ATSDR prepared a third public health consultation as a follow-up to questions raised in a previous health consultation regarding potential exposures to contaminants through indoor dust and ambient air. Residential Soil, Indoor Dust, and Ambient Air reviewed results from surface soil, indoor dust, and ambient air sampling conducted at three homes on Old Mine Road in November 2000 (ATSDR 2001). On the basis of available data, ATSDR concluded that metals detected in surface soil from residential yards were not expected to cause adverse health effects. Lead detected in indoor dust was determined to be a potential health concern. Other metals detected in indoor dust posed neither an acute nor a chronic health hazard from inhalation, dermal contact, or ingestion. Metals found in ambient air posed neither an acute nor a chronic health hazard from inhalation, dermal contact, or ingestion.