PUBLIC HEALTH ASSESSMENT
TIBBETTS ROAD
BARRINGTON, STRAFFORD COUNTY, NEW HAMPSHIRE
The Tibbetts Road National Priorities List site is a former residential property where the owner possessed at least 337 55-gallon drums of which 201 drums contained various materials. Initial sampling of the contents of these drums indicated the presence of acetone, benzene, toluene, xylenes, trichloroethene, and 4-methyl-2-pentanone. Subsequent sampling of these drums indicated high concentrations of polychlorinated biphenyls (PCBs). It is believed that the owner brought the barrels to his residence (the site) during the period of 1948-1953. The owner mainly used these materials as a fuel supplement for burning in automobile engines. In addition, the materials were used to burn the upholstery from the interior of automobiles on his property that were intended for salvage. Thirty to forty junk automobiles originally at the site have been removed. Because of past disposal and other activities at the site, about 10 former residents and children were exposed in the past to on-site contaminants. In addition, groundwater contamination at the site has resulted in past exposure of about 30 individuals through their use of private well water.
Based on information reviewed, the ATSDR has concluded that the Tibbetts Road site is a public health hazard primarily because of past exposure to hazardous substances at levels that may cause adverse health effects. Former residents of the building on the site, especially children who once played on the site, were exposed to PCBs and PCE through ingestion from either contaminated surface water or soil at levels that could cause neurological signs, blood problems and suppression of immunological functions. In addition, PCE and PCBs in soils on the site could result in a slightly low to high increased risk of cancer. The site currently represents a no apparent public health hazard.
Residents who used the residential well water one-half mile from the site were exposed to acetone (may be partly site-related), manganese (may not be site-related), and propylene glycol (probably not site-related) at levels that could cause adverse health effects. Based on animal studies, less serious anemia, liver and kidney problems could occur after less than one year of continuous exposure to acetone, and mild neurological signs and diminished brain function could occur after one to 50 years of continuous exposure to manganese. In addition, mild skin rashes could occur in infants and young children after acute/short duration of exposure to propylene glycol. These residents have been provided a permanent alternate water supply by the United States Environmental Protection Agency (EPA).
Ingestion, inhalation, and skin contact exposure to benzene and TCE, through the past use of residential well water, within the immediate vicinity of the site is unlikely to result in any non-carcinogenic adverse health effects. However, we estimate that exposure to benzene through use of the most contaminated well within the immediate vicinity of the site may result in a low increased risk of cancer. Workers and campers who used the Len-Kay Campground well water are unlikely to suffer adverse health effects because of the low levels and short duration of past exposure to TCE in the well water. However, long term use of the Len-Kay Campground Well should be reconsidered because continuous exposure to even low levels of a suspect carcinogen should be avoided. The campground has been provided a permanent alternate water supply by the EPA.
Citizens raised several health concerns related to past exposure to site contaminants on-site and through the past use of contaminated private well water. Detailed answers to these concerns appear in the Public Health Implications section and the Response to Public Comments of this Public Health Assessment.
The Agency for Toxic Substances and Disease Registry
(ATSDR) made
recommendations to reduce and prevent exposure to contaminants.
The Environmental Protection Agency's (EPA) selected remedial
alternative (cleanup method), once implemented, will be protective
of public health. ATSDR's Health Activities Recommendation Panel
(HARP) has determined that persons exposed to TCE and/or benzene
contaminated drinking water be considered for inclusion in the
subregistries for those contaminants and that further community
involvement may be needed if public comments indicate an ongoing
need for persons who have been exposed to understand their
exposure. ATSDR has reviewed public comments and determined that
additional education is needed for the residents of one household,
that was exposed to manganese and acetone (may not be site-related), and their physician. This
education will be provided by
the New Hampshire Division of Public Health Services (NHDPHS). The
New Hampshire Department of Environmental Services and the NHDPHS
will continue to monitor drinking water wells and will provide
health information to private well owners in the area,
respectively. The EPA plans to identify potentially affected
private wells in the area, establish regular monitoring programs,
and implement institutional controls to restrict the use of
contaminated well water in the area.
The Agency for Toxic Substances and Disease Registry (ATSDR) will evaluate the public health significance of the Tibbetts Road Hazardous Waste site. More specifically, ATSDR will determine whether health effects are possible and will recommend actions to reduce or prevent possible health effects. ATSDR, located in Atlanta, Georgia, is a federal agency within the U.S. Department of Health and Human Services and is authorized by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as amended, to conduct public health assessments at hazardous waste sites. The CERCLA legislation is commonly called "Superfund".
A. SITE DESCRIPTION AND HISTORY
The Tibbetts Road site is in the Town of Barrington, Strafford County, New Hampshire about eight miles west of the City of Dover, New Hampshire (1). On July 10, 1986, the site was finalized for inclusion on the U.S. Environmental Protection Agency's (EPA) National Priorities List of uncontrolled hazardous waste sites (2).
On the basis of a complaint, the New Hampshire Division of Public Health Services (NHDPHS) investigated the site in April and May of 1982. The owner of a residence on Tibbetts road possessed at least 337 55-gallon drums of which 201 drums contained various materials. Initial sampling of the contents of these drums indicated the presence of acetone, benzene, toluene, xylenes, trichloroethene, and 4-methyl-2-pentanone. Subsequent sampling of these drums indicated high concentrations of polychlorinated biphenyls (PCBs). It is believed that the owner brought the barrels to his residence (the site) during the period of 1948-1953. The owner mainly used these materials as a fuel supplement for burning in automobile engines. In addition, the owner used the liquids to burn the upholstery from the interior of automobiles on his property that were intended for salvage (1). Thirty to forty junk automobiles originally at the site have been removed.
Analysis of residential wells in the vicinity of the site by the New Hampshire Water Supply and Pollution Control Commission (NHWSPCC) in June 1982 indicated the presence of contamination in one of these residential wells. After June 1982, monitoring of other nearby residential wells was continued on a quarterly basis. In January 1984 Volatile organic compounds (VOCs) were detected in a second residential well located about 250 feet north of the site. In 1987, EPA began construction of a water supply system to provide drinking water for the residents affected by the site. A nearby lake, Swains Lake, was selected to be the source of this alternate water supply (1). This water system was completed in the Fall of 1987. Between 1985 and 1987, bottled water was provided to those residents with contaminated wells (3).
In March 1984, the NHDPHS and the NHWSPCC collected soil and surface water samples for analysis from three areas containing drums, known as Areas A, B, and C (Appendix A, Figures 1 and 2). The results of the analysis of these samples prompted the NHDPHS to request the EPA to intervene in an emergency removal of all drums, which was completed by May 1984. The 221 drums were analyzed for compatibility and consolidated into 82 drums prior to off-site transport to a disposal site. During EPA's removal action, soil samples were collected from three drum storage areas to determine the presence of residual soil contamination. The analysis of these soil samples indicated the presence of total VOCs up to 2,179 parts per million (ppm). In addition, because of the presence of PCBs in soil samples obtained in October 1985, the EPA included analyses for dioxins and furans during extensive soil sampling between July and August 1985 (1). It is believed that dioxins and furans were formed as combustion by-products when the interior of the salvaged automobiles were burned using waste liquids that contained PCBs from the on-site drums (1).
In July 1985, the NHDPHS and the New Hampshire Department of Public Works and Highways placed a snow fence around the highest levels of soil contamination at the site. Also, a temporary tarp was placed over the areas of soil exhibiting PCB, dioxin, and furan contamination. In October 1985, the EPA assigned a 24-hour guard to the site to prevent trespassing (1).
After the site was secured, on-site soils and standing water exhibiting high concentrations of contaminants were excavated and disposed of off-site. The EPA and NHDPHS conducted a joint soil removal operation in March and April 1986. Additional sampling was performed by NHDPHS to insure the removal of all highly contaminated soils. Excavated areas were regraded with clean fill, then covered with an impermeable liner material. Loam and seed were spread over the regraded areas, and a chain-link fence was erected around the site. The PCB and dioxin contaminated soil were temporarily contained in a well secured dumpster. EPA then brought in a mobile incinerator to provide on-site thermal destruction of the PCB and dioxin contaminated soils (1).
After the excavation and disposal of soil were completed, about five gallons of a herbicide was spilled on-site. Sampling and analyses by EPA of a residue and soil sample collected after the herbicide spill revealed elevated concentrations of 2,4,5-T and 2,4-D (28,000 ppm 2,4,5-T and 54,270 ppm 2,4-D in the residue sample; and 1,470 ppm 2,4,5-T and 2,420 2,4-D in the soil sample). The contaminated soil and container were disposed of properly by the NHDPHS (4).
The site currently consists of an unoccupied single family residence in which the former owner of the site and his family once lived (2). The house located on-site has been partially destroyed by a fire that occurred in October 1982. This fire did not affect the drums that were stored on-site. Currently, there are no remedial or other activities at the site. Access to the site is restricted by an eight foot fence with barbed-wire around the top perimeter. See the Site Visit section below for more information on the current status of site.
Between 1984 and 1987, ATSDR or the Centers for Disease Control (CDC) performed six health consultations. On-site soil contamination and residential well contamination data, provided by EPA, were evaluated for their significance to public health. In addition, a brief health assessment, based on limited residential well data, was issued on January 7, 1986.
EPA issued a Remedial Investigation (RI) and Feasibility Study (FS) in June 1992. EPA signed a Record of Decision (ROD) for the site on September 28, 1992. EPA's selected cleanup alternative would include the following elements (5):
B. ACTIONS IMPLEMENTED DURING THE PUBLIC HEALTH ASSESSMENT PROCESS
The following actions were taken at the site while the public health assessment process was in progress:
On November 5, 1991, Gregory Ulirsch and Dr. Moses Kapu, ATSDR headquarters staff, and Susanne Simon and Edward Bazenas, ATSDR Region I Representatives, conducted a site visit of the Tibbetts Road site. The site visit was conducted with the EPA Remedial Project Manager (RPM). Also accompanying us on the visit were the Town Health Officer and Executive Administrator for Barrington, New Hampshire. About two hours were spent in the field conducting the visit.
The following observations and information were obtained during the site visit:
According to the EPA RPM, the site conditions have not changed appreciably since the 1991 site visit (personal communication, June 11, 1993).
D. DEMOGRAPHICS, LAND USE, AND NATURAL RESOURCE USE
Demographics
Based on 1990 census information (6), about 6,164 persons reside in the town of Barrington, New Hampshire. Within Barrington there exists 2,217 housing units; hence, the number of persons per occupied housing unit is 2.78. Based on the number of residences located within 200 feet and one-mile of the site (see Land Use below), 14 and 556 persons reside within 200 feet and one-mile, respectively, of the site. The population of Strafford County is about 104,233.
The 1.9 acre site is in an rural, moderately developed residential neighborhood. Five occupied, single family dwellings lie within 200 feet of the site. About 200 homes lie within a one mile radius of the site (2). Seasonal homes are located along Swains Lake.
Natural Resource Use
A drinking water supply system, installed in 1987 by the EPA and NHDES, supplies the residents of 46 of the approximately 70 homes within a one-half mile radius of the site. After the water supply system was established, all the residential wells that had been used were capped (1). All residents within one-quarter mile of the site receive their drinking water from this system. Prior to 1987, those residents received their drinking water from wells which draw water from either the bedrock or overburden aquifer wells. An aquifer consists of rock or rock materials that are sufficiently permeable to conduct groundwater and to yield sufficient quantities of water to wells or springs. Residences which still receive their drinking water from private wells (overburden and bedrock wells) are outside the one-quarter mile radius of the site. Some of these wells serve residences that abut Swains Lake on Hall Road, Stadig Road, and Acorn Point Road (2). These residences that abut Swains Lake have overburden (shallow) aquifer wells that draw primarily recharge water from the lake. The Len-Kay Campground has a bedrock (deep) aquifer well (7) that is no longer used as a source of water for the campground.
The closest major water body to the site is Swains Lake, which is about 900 feet north of the site. This lake serves as the source for the drinking water supply system. The State of New Hampshire has classified the Swain's Lake as "B", not suitable for drinking water without treatment (2). The Swains Lake is popular for recreational activities such as boating, fishing, swimming and is the headwaters for the Bellamy River which feeds a reservoir that serves as the water supply source for Portsmouth, New Hampshire (8) (Appendix A, Figure 3).
The site is on the drainage divide for Swains Lake and the Oyster River. The site, as well as surrounding residential properties are poorly drained, and ponding occurs locally following rain storms or in times of a high water table (e.g., in springtime). The site has no definitive stream channels. An intermittent unnamed stream is about 500 feet southwest of the site and flows towards Oyster River, which is about one mile away from the site. The flow in the intermittent stream varies seasonally with the largest flow occurring in the spring (1).
Health outcome data were not evaluated for this site because the
population of concern (about 40 persons) is a very small
population. Details of why they were not analyzed are presented in
the Public Health Implications--Health Outcome Data Evaluation Sub-section.
On November 4 and 5, 1991, ATSDR staff held two public availability meetings to gather community concerns. These sessions were held between 7-9 p.m. at the Barrington Elementary School. About 13 private citizens discussed community concerns with ATSDR staff. The availability sessions were announced through an ATSDR Press Release (10/21/91) and through the assistance of the Barrington Health Officer. In addition, this public health assessment has been placed for public comment. The details of this public comment period and ATSDR's response to comments are shown in Appendix B.
In general, citizens of Barrington who attended the meetings were concerned about health effects resulting from drinking contaminated well water, the presence of the old house on the site, and property values and taxes. A detailed description of their concerns is as follows:
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