PUBLIC HEALTH ASSESSMENT
ELECTROSONICS/SPOFFORD PLACE (FORMER)
CHESTERFIELD, CHESHIRE COUNTY, NEW HAMPSHIRE
The former Electro-Sonics facility is located on Main Street (NH Route 9A) in Spofford Village (Chesterfield), New Hampshire. The facility manufactured electronic circuit boards from December 1966 until February, 1984, when it moved to Vermont. The facility is currently inactive, although three small businesses still use Building No. 2, on the northern parcel of the facility.
On December 19, 1999, the New Hampshire Department of Environmental Services (DES) released a report summarizing environmental conditions at the former Electro-Sonics site. On April 30, 2001, DES released a supplemental site investigation at the site. Due to high levels of contamination in both soil and groundwater, the New Hampshire Department of Health and Human Services (DHHS) completed this Public Health Assessment under its cooperative agreement with ATSDR.
What kind of contamination has been found at the site?
At the former Electro-Sonics facility, circuit boards were machined and etched; Buildings No. 1, No.
2 and No. 3 were used to complete this process as well as store raw materials and waste.
Wastewater 
from electroplating, etching and rinsing of circuit boards was dumped into an earthen
basement in Building No. 2 until 1968. At this point, the New Hampshire Water Supply and
Pollution Control Commission (WSPCC), the antecedent to the Department of Environmental
Services, required Electro-Sonics to discharge waste into a subsurface leach field between Building
Nos. 1 and 4, on the northern parcel of the site. This leach field disposal system ultimately proved
inadequate for the volume of wastewater, which resulted in subsurface breakout and overflow of
effluent into Partridge Brook. Between approximately 1968 and 1974, numerous complaints were
made to the WSPCC about discoloration and other visual impacts to the brook (Sanborn 2001).
During this same period, the New Hampshire Department of Fish and Game ceased stocking the
brook since high mortality of stocked fish was observed (DES Personal Communication 2002).
Discharge into Partridge Brook is alleged to have occurred into the 1980s, at which point it was
regulated as a generator of hazardous waste by the U.S. Environmental Protection Agency and the
New Hampshire DES.
The main contaminants at the site are chromium, copper, lead, chlorinated volatile organic compounds (VOCs) and petroleum-related compounds. Chromium, copper and lead were used to plate and etch circuit boards while chlorinated VOCs were used in the cleaning and degreasing process. Petroleum products found on the site are related to reoccurring spills of fuel oil from above-ground storage tanks and fuel line breakage.
Due to the chemical properties of many chlorinated VOCs, large amounts of several types of these chemicals have been found in local groundwater, including the site supply well, on-site test wells and off-site residential supply wells. All nearby wells were tested in 1998 through the present. Residential wells found to be contaminated were supplied with point-of-entry filtration systems.
In addition to waste generated by industrial processes, three documented oil releases occurred in 1984, 1988 and in 1989. These spills released 25, 400 and 600 gallons of fuel oil, respectively. All of these releases reportedly were released into Partridge Brook and into soils on the northern parcel.
How might I be exposed to chemical contamination on the site?
Wading or playing in Partridge Brook is the only way that people can currently be exposed to chemicals related to the site.
There are three ways that people could have been exposed to chemicals in the past:
There are four ways that people could potentially be exposed to chemicals, although one or more of the elements of exposure are not certain:
What health effects might result from exposure to chemical contamination at the site?
None of the current exposures at the site are expected to cause adverse health effects. Therefore, DHHS has categorized current conditions at the site as No Apparent Public Health Hazard according to ATSDR's hazard classification system. However, site remediation is needed because, in the future, changes in the land use could increase exposures to levels that could potentially cause adverse health effects.
In the past, there were exposures to multiple VOCs in several private wells near the site. Contamination in all but two wells were low enough that adverse health effects are not expected to have occurred. The most serious exposures occurred in Residential Well Nos. 1 and 2 where exposure to trichloroethylene, 1,1-dichloroethylene and vinyl chloride could potentially cause a low to moderate theoretical risk of cancer. For the other wells, the known exposures were unlikely to result in adverse health effects. It is not known whether any residents lived there long enough, or if the contamination began early enough for such long-term exposures to occur.
Could current or past exposures to chemical contamination at the site have caused an increased rate of cancer in the community?
Due to the small population of the area around the site, health outcome data were not analyzed. However, two of the residential wells near the site had extremely high levels of contaminants (several wells had contaminants above the detection limits, although most of these contaminants were below levels in which health effects are possible). Theoretically, exposure to these contaminants could have created an increased risk of cancer from exposures over several years.
Is the site being cleaned up?
From December 1999 to April 2001, the New Hampshire Department of Environmental Services (DES) performed an environmental characterization of the site and affected areas off-site. Residential wells with contamination had point-of-entry water filtration systems installed. In September 2000, DES covered the area between Building Nos. 1 and 2 with a layer of gravel, due to concerns about odors of VOCs (these odors were noted during digging of test pits). Drinking water was provided in the buildings where businesses currently reside. Current workers have been warned about the contaminants in the on-site supply well.
EPA is currently working with DES on a cleanup strategy for the rest of the contamination at the site.
Where can I get more information?
The text and appendices of the Public Health Assessment contain more information about the health issues discussed in this summary. To ask questions about this Public Health Assessment or to obtain extra copies of this document, please contact Dennis Pinski in the DHHS Bureau of Environmental and Occupational Health at (603) 271-4664 or (800) 852-3345 ext. 4664 (toll-free in N.H.). You can also send an e-mail to the Bureau at healthrisk@dhhs.state.nh.us to request a copy of the document. Additional copies of this Public Health Assessment will be available at the Chesterfield Town Library at 524 Route 63, Chesterfield, NH, 03443-3607 (603) 363-4621.
If you would like more information on the site cleanup efforts, please contact John F. Liptak, site project manager, of the New Hampshire DES at (603) 271-1169.
Between December 1999 and April 2001, the New Hampshire Department of Environmental Services (DES) performed an environmental characterization of the site and affected areas off-site. Due to apparent contamination of various media (including drinking water), DHHS performed this Public Health Assessment. A Public Health Assessment is a triage tool used to determine if any actions are needed to protect the community surrounding a hazardous waste site, and to determine if follow-up health activities (e.g., health studies, medical surveillance) should be done. To achieve this goal, this assessment contains three types of evaluations: (1) the identification of pathways of exposure to site contaminants and an evaluation of their public health implications; (2) a summary of relevant and available health outcome data (i.e., cancer registry data); and (3) an evaluation of specific community health concerns about the site.
The New Hampshire Department of Health and Human Services (DHHS) completed this Public Health Assessment under its cooperative agreement with ATSDR.
(A) Site Description and History
The former Electro-Sonics facility is located on Main Street (NH Route 9A) in Spofford Village (actually located in the town of Chesterfield), New Hampshire, in an area of mostly residential development. The site consists of two separate one-acre plots. The northern parcel, on the north side of Main Street, contains Building Nos. 1, 2 and 4, while the southern parcel, on the south side of Main Street, contains Building Nos. 3 and 5. While there are records of storage of hazardous materials on the southern parcel, there is no indication of chemical use on this section of the site. The facility produced electronic circuit boards from 1966 through 1984.
Machining, etching and cleaning of circuit boards resulted in the production of waste-waster containing metals such as chromium and copper, as well as chlorinated VOCs. These contaminants were sometimes stored, but often they were dumped into an earthen basement in Building No. 2. In 1968, the practice of dumping into the basement ceased and Electro-Sonics began draining all waste material into a subsurface leach field between Building Nos. 1, 2 and 4. This leach field frequently overflowed, and by the 1980s, waste was being discharged into Partridge Brook on a regular basis.
Partridge Brook wraps around the north and west edges of the northern parcel and along the south edge of the south parcel. Building No. 2 is within a few feet of the brook.
There are no barriers to access (e.g., fences) on any part of the property.
There are two businesses that occupy space in Building No. 2. Although waste was dumped in the earthen basement of this building, the basement is not accessible to the employees of the current businesses; the employees of the businesses also do not need to be in the area of the leach field or alleyway to access their work.
Following the environmental characterization of the site, DES assessed the affected areas off-site. 25 residential wells were tested for contamination. Residential wells with contamination had filtration systems installed. These filters were installed at the "point-of-entry", i.e., all water entering the house is filtered. In September 2000, DES covered an area between Building Nos. 1 and 2 with a layer of gravel, due to concerns about observed odors after the digging of test pits. Workers in Building No. 2 were advised not to drink water from the site supply well. Current workers have been warned about the contaminants in the on-site supply well.
EPA is working with DES on a cleanup strategy for the site.
DHHS began work on a Public Health Assessment in May 2002. DHHS staff have performed site visits and conducted outreach activities with the community. Highlights of DHHS involvement to date are provided below.
DES and DHHS, as well as their predecessor agencies, WSPCC and the Division of Public Health Services (DPHS) have been active in enforcing regulations, characterizing site conditions and providing information to Spofford Village residents. DES and EPA are currently working on a cleanup strategy for the site. Highlights of involvement are provided below.
Spofford Village is located within the town of Chesterfield, New Hampshire. According to the 2000 Census, 316 people live within an approximate half-mile radius of the site. The town of Chesterfield has a population of 3,542. Children less than 5 years old and adults over 65 years old accounted for 16% of the population. The age distribution for the population of the town of Chesterfield is summarized in Table 1.
More than half of Chesterfield residents have lived in their current homes for less than 10 years (Table 2). However, the DHHS Needs Assessment survey indicated that for the residents living near the site who responded to the survey, three respondents have lived at their current address for less than 5 years (Appendix D).
(E) Quality Assurance/Quality Control (QA/QC)
In preparing this document, DHHS relied on the information provided in the referenced documents. Only data collected using appropriate sampling and laboratory methods were considered in this analysis. Data with demonstrated QA/QC problems were excluded from summary tables or exposure analysis unless they provided unique and relevant information. DHHS has confidence in the data for the site because the tests were performed by certified laboratories. Measurements of exposure point concentrations were taken directly from laboratory data sheets to avoid transcription errors.
The health outcome data used in this evaluation were also checked for quality control purposes and measures were taken to ensure that these data were appropriate.
III. ENVIRONMENTAL CONTAMINATION
An integral element of every public health assessment is a review of environmental contamination on the site. In the following section, the results from environmental testing at the former Electro-Sonics Site are summarized for each media (e.g., waste, groundwater, soils, etc.).
Concentrations of chemicals in each of the media have been compared to media-specific health-based comparison values to decide whether any of the compounds need further evaluation. Health-based comparison values are derived using information on the toxicity of the chemical and assuming frequent opportunities for exposure to the contaminated media (e.g., a residential setting). For non-cancer toxicity, DHHS typically uses ATSDR Minimal Risk Levels or EPA Reference Doses, which are estimates of daily human exposure to a contaminant that is unlikely to cause adverse non-cancer health effects over a lifetime. Cancer risk comparison values are based on EPA chemical-specific cancer potency factors and an estimated excess lifetime cancer risk of one in one million.
If the concentration of a chemical is less than its comparison value, it is unlikely that exposure would result in adverse health effects, and further evaluation of exposures to that chemical is not warranted. If the concentration of a chemical exceeds a comparison value, adverse health effects from exposure are not necessarily expected, but potential exposures to that chemical at the site should be evaluated. As a result, the following summary of environmental data highlights the chemicals that have been found on the site at concentrations above health-based comparison values. Please see Appendix E for more information on health comparison values.
In the Discussion section later in this document, there will be an evaluation of the public health implications of exposure to contaminants with concentrations greater than health comparison values.
(A) Site Conceptual Model - An Overview of the Former Electro-Sonics Site
A site conceptual model is a general description of the processes and the conditions that have been observed at a particular site. It is meant to provide the reader with an overview of the site so that the detailed information provided in the following sections can be taken in context.
At the site, a printed circuit board manufacturing business was in operation from 1966 through 1984. Wastewater used in the etching and cleaning of the circuit boards contained VOCs and metals. For much of the facility's operation, this waste was discharged either directly or indirectly into Partridge Brook and a subsurface leach field. Manufacturing waste was also dumped on the dirt floor of the basement in Building No. 2.
The main chemicals of interest at the site are metals such as chromium, lead and copper, and chlorinated VOCs. Metals are used in the etching and plating of the circuit boards. VOCs were used as cleaning/degreasing agents. Chlorinated VOCs are chemicals that have chlorine atoms attached to the molecule.
Electro-Sonics documents indicate that several of these compounds were used. In this Public Health Assessment, several VOCs are mentioned; this is due to the parent compounds (in the waste produced by Electro-Sonics) breaking down into various daughter compounds. Chlorinated VOCs are generally not very soluble in water. They are frequently found in soil and groundwater at contaminated waste sites. Once released into soil, they assume 'dissolved phase' and can quickly reach the groundwater. Once in the groundwater, they form a dense layer at the bottom of the aquifer that can be extremely difficult to remove.
(1) Northern Parcel - Former Subsurface Leach field and Alleyway
Contaminated soil has been found in the area surrounded by Building Nos. 1, 2 and 4, where wastewater drained (the subsurface leach field). The results of 11 soil gas samples and 3 test pits are presented in Tables 3 and 4. The chemicals of interest are VOCs and hydrocarbons related to previous oil spills.
The chemical concentrations in soil gas cannot be compared to health comparison values for two reasons: First, soil gas measurements examine compound levels that exist in the air spaces between soil particles. These values do not represent what would be inhaled in the air. Second, test pit measurements were taken at depths well below the level of soil that a person would be exposed to (i.e., subsurface soil). Therefore, DHHS evaluated these compounds of interest in a qualitative fashion.
Tables 3 and 4 show high levels of several types of chlorinated compounds and several petroleum-related VOCs. A wide variety of chemicals are listed, especially for chlorinated compounds, which could be the result of degradation of one or more compounds.
(2) Southern Parcel
Although there has been limited soil testing onsite, there have been scores of test pits and borings to identify the areas of waste disposal. Very limited contamination was encountered in the 2 borings taken in the southern parcel (Sanborn 2001). All contaminants in the soil borings were below their respective comparison values. Moreover, wastes were not handled or disposed of on the southern parcel. Therefore, no health effects from soil contamination are expected on the southern parcel.
(C) Partridge Brook Surface Water
In August 1999, surface water samples were collected from four locations in Partridge Brook. Sampling locations were selected to assess water quality conditions both upstream and downstream from the site. Surface water samples were analyzed for total metals, VOCs, cyanide and natural attenuation parameters (pH, conductivity, etc.).
All chemicals from all samples were below the detection limits. This indicates that while spills and discharge may have occurred in the past, there are no chemicals that are still affecting the water.
In 1999, two sediment samples were collected from Partridge Brook, adjacent to the northern parcel, where most spills are believed to have occurred. Sediment samples were analyzed for metals (arsenic, cadmium, chromium, copper, lead, mercury, nickel and zinc), VOCs and total cyanide (Table 5).
For cadmium, the concentrations (2.9 and 3.0 ppm) were higher than the established background level (1.9 ppm). The concentrations are below the comparison value for cadmium (10 ppm). Therefore, the average cadmium concentrations in the brook appear to be below levels of health concern.
Levels of copper (1,200 and 1,300 ppm) were also well above established background levels (22 ppm). However, due to the relative high toxicity threshold of copper, these levels were below the comparison value (3,100 ppm). Therefore, the average copper concentrations in the brook appear to be below levels of health concern.
Levels of lead (150 and 230 ppm) were also above its established background level (54 ppm). These levels were below the comparison value of 400 ppm. Therefore, the average lead concentrations in the brook appear to be below levels of concern.
One of the samples showed a level of zinc (120 ppm) above its established background level (98 ppm). This level was also below the comparison value (1,000 ppm). Therefore, the average zinc concentrations in the brook appear to be below levels of health concern.
No polycyclic aromatic hydrocarbons (PAHs, a group of potentially cancer-causing substances) were detected in the sediment samples. Low levels of 1,1,1-trichloroethane (0.16 ppm) were found in both samples. These levels are far below the comparison value (22,000 ppm). Trichloroethylene was also detected in one sample (0.08 ppm). This level was well below its comparison value (2 ppm). Therefore, the average concentrations for these VOCs appear to be below levels of health concern.
The levels of chromium (340 and 3,900 ppm) were higher than the established background level. It is likely that releases of wastewater from Electro-Sonics resulted in high levels of chromium in the stream sediments. Even though no laboratory tests were conducted to determine the type of chromium in Partridge Brook, it is expected to be mostly in the hexavalent form since this type of chromium is most associated with plating/etching operations (ATSDR 2000). If left over time, hexavalent chromium is reduced to trivalent chromium, which is less toxic (ATSDR Personal Communication 2002). As a conservative measure, comparison values for hexavalent chromium were used. Both sediment samples had chromium levels above the comparison value (230 ppm). The maximum detected value was nearly twenty times higher than the comparison value.
In 2000, DES analyzed 5 additional sediment samples from partridge brook, along the northern parcel of the facility (Table 6). One sample contained 1,2,4-trimethylbenzene (0.26 ppm) and 1,3,5-trimethylbenzene (0.19 ppm) and p-isopropyltoluene (0.14 ppm). All of these compounds were below their comparison values (3,900 ppm, 3,900 ppm and 73,000 ppm, respectively).
Beneath the site, the water table occurs at approximate depths of between 3-6 feet. Under the northern parcel of the site, groundwater flow is in a north to northwest direction, toward Partridge Brook. Under the southern parcel, groundwater flows south, again toward Partridge Brook.
Several VOCs were detected above their comparison values in groundwater samples from the former Electro-Sonics site supply well (Tables 7a & 7b). The VOCs included were chloroethane (130 ppb), 1,1-dichloroethane (5,200 ppb), 1,2-dichloroethane (7 ppb), 1,1-dichloroethylene (570 ppb), cis-1,2-dichloroethylene (660 ppb), dichloropropane (1.5 ppb), methylene chloride (12 ppb), tetrachloroethylene (200 ppb), 1,1,1-trichloroethane ( 3,300 ppb), 1,1,2-trichloroethane (6 ppb), trichloroethylene (1,100 ppb) and vinyl chloride (300 ppb). Several other VOCs were detected at concentrations below their respective comparison values in groundwater samples.
The majority of chemicals detected in wells are more dense than water. Once released into the ground, these chemicals are not stopped by layers of groundwater, and continue migrating downward until they are stopped by the aquitard (a layer of rock which confines the flow of groundwater).
(G) Off-Site Residential Supply Wells
All residences in Spofford Village obtain their water from private wells. Water supply wells were tested based on the probable hydrogeology of the site (i.e., a house whose well is upgradient from the site was not tested, while a very deep well downgradient was tested). A total of twenty-eight wells were sampled, including the Electro-Sonics site supply well, twenty-six residences, and a day care center. Wells were sampled from two to five times over a two-year period. Samples from these wells were tested for VOCs and petroleum-related compounds. DES installed point-of-entry charcoal filtration systems on contaminated residential wells. Twenty wells showed no signs of contamination, including the day care center. The site supply well, as well as Residential Wells Nos. 1, 2, 3, 4, 12, 15, and 27 (well locations are represented by numbers to ensure confidentiality) had detectable levels of VOCs.
Several wells showed similar types of chlorinated VOCs. Most commonly seen in residential wells were 1,1-dichloroethylene, trichloroethylene, and vinyl chloride. These compounds are similar (but not the same, due to degradation of compounds) to the compounds used in the cleaning and degreasing of circuit boards, making it likely that the contamination emanated from the former Electro-Sonics facility.
(1) Residential Well No. 1
Multiple VOCs were detected above their comparison values in groundwater samples from Residential Well No. 1 (Table 8). The VOCs included were 1,1-dichloroethane (1,600 ppb), 1,1-dichloroethylene (51 ppb), cis-1,2-dichloroethylene (180 ppb), trichloroethylene (53 ppb) and vinyl chloride (53 ppb). Several other VOCs were detected at concentrations below respective comparison values in groundwater samples.
(2) Residential Well No. 2
Several VOCs were detected above their comparison values in groundwater samples from Residential Well No. 2 (Table 9). The VOCs included were 1,1-dichloroethylene (9.1 ppb), trichloroethylene (51 ppb) and vinyl chloride (35 ppb). Several other VOCs were detected at concentrations below respective comparison values in groundwater samples.
(3) Residential Well No. 3
Three VOCs were detected above their comparison values in groundwater samples from Residential Well No. 3 (Table 10). The VOCs included were 1,1-dichloroethylene (0.55 ppb), trichloroethylene (0.66 ppb) and vinyl chloride (0.62 ppb). Two other VOCs were detected at concentrations below respective comparison values in groundwater samples.
(4) Residential Well No. 4
In Residential Well No. 4, only benzene (0.71 ppb) was detected above its comparison value (Table 11). Chloroform was also present, although it was below its comparison value. It is not certain whether these two compounds are related to the site since they have not been detected in other wells.
(5) Residential Well Nos. 12 and 15
In Residential Well Nos. 12 and 15, chloroform was detected (at 3 ppb and 4 ppb, respectively). These levels were below the comparison value of 6 ppb. Chloroform may be present in these wells due to prior well disinfection with chlorine.
(6) Residential Well No. 27
In Residential Well No. 27, chloroform and toluene were detected (at 4.3 ppb and 0.75 ppb, respectively). These levels were below the respective comparison values of 6 ppb and 2,000 ppb. Again, chloroform may be present due to prior disinfection with chlorine. Toluene is most likely a site related chemical; it is present at levels 2000-fold less than the comparison value.
Prior to the installation of the subsurface leach field, waste was commonly dumped in the earthen basement of Building No. 2. Chemicals were also stored in this area. Three businesses still occupy the floor above the basement.
Two samples of the ambient air in the basement showed elevated levels of VOCs. The maximum level of 1,1-dichloroethylene (0.77 µg/m3) was above its comparison value of 0.036 µg/m3 (Table 12). This level was also above the Cancer Risk Evaluation Guide (CREG), an estimated contaminant concentration that would be expected to cause no more than one additional excess cancer in a million persons exposed over a lifetime.
Two samples from the surface soil in the basement indicate elevated levels of lead, arsenic and benzo[a]pyrene (Tables 13a & 13b). The maximum values were above the respective comparison values of 400, 0.05 and 0.1 parts per million, respectively. The maximum level of lead was 75 times higher than its comparison value.
Soil contamination was most likely limited to the alleyway and subsurface leach field between Building Nos. 1, 2 and 4. The topography of the site is such that any runoff would go into Partridge Brook.
Downstream from Electro-Sonics, Partridge Brook runs north into the town of Westmoreland, where it continues in a northwest direction, ultimately draining into the Connecticut River. While the sections of the brook adjacent to the two parcels of the site have been tested, there has been no sampling of the surface water or sediment in its downstream section.
It is unlikely that the chemicals found adjacent to the site would be found in higher concentrations downstream. Additionally, the chemicals that were found above background levels or above comparison values are metals with relatively small potential for bioaccumulation in fish (e.g., trout and bass) (ATSDR 2000; ATSDR 1999a; ATSDR 1999b; ATSDR 1994; ATSDR 1990a).
(J) Physical and Other Hazards
No physical hazards were apparent at the site. The buildings are secured from trespassers, especially the basement of Building No. 2. While some refuse is visible in the site, no remaining equipment or other potential physical hazards were observed during the site visit.
IV. PATHWAYS OF HUMAN EXPOSURE
To determine whether nearby residents are exposed to contaminants from the site, ATSDR and DHHS evaluated the environmental and human components that lead to human exposure. This pathways analysis consists of five elements: (1)a source of contamination; (2) transport of contaminants through an environmental medium;(3) a point of human exposure; (4) a route of human exposure; and, (5) a receptor population. ATSDR classifies exposure pathways into three groups: (1) completed pathways; i.e., those in which exposure is reasonably likely to have occurred, to occur, or to occur in the future; (2) potential pathways; i.e., those in which exposure might have occurred, may be occurring, or may yet occur; and, (3) eliminated pathways; i.e., those that can be eliminated from further analysis because one of the five elements is missing and will never be present, or in which no contaminants of concern can be identified.
After the pathways are designated as completed, potential, or eliminated, ATSDR usually follows a two-step methodology to comment on public health issues related to exposure pathways at hazardous waste sites. First, ATSDR obtains representative environmental monitoring data for the site of concern and compiles a list of site-related contaminants. ATSDR compares this list of contaminants to health-based comparison values (HCVs) to identify those contaminants that do not have a realistic possibility of causing adverse health effects. These comparison values are conservative, because they include ample safety factors that account for the most sensitive populations. ATSDR typically uses HCVs as follows: if a contaminant is never found at levels greater than its comparison value, ATSDR concludes the levels of corresponding contamination are not at levels of public health concern. If, however, a contaminant is found at levels greater than its HCV, ATSDR designates the pollutant as a contaminant of concern and examines it further in the assessment. Because HCVs are based on conservative assumptions, the presence of concentrations greater than a HCV does not necessarily suggest that adverse health effects will occur among the exposed population. More information on the comparison values can be found in Appendix G.
For the remaining contaminants, ATSDR evaluates site-specific conditions to determine what exposure scenario is realistic for a given exposure pathway. Given this exposure scenario, ATSDR determines a dose and compares this dose to scientific studies to determine whether the extent of exposure indicates a public health hazard.
(A) Completed Exposure Pathways
Environmental contamination cannot affect a person's health unless he or she comes into contact with it. Likewise, human contact with environmental contamination is only possible when a completed exposure pathway exists. A completed exposure pathway exists when all five of the following elements are present: (1) a source of contamination; (2) transport through an environmental medium; (3) a point of exposure; (4) a route of human exposure; and (5) an exposed population. For the former Electro-Sonics site, the completed exposure pathways are listed in the following table.
Completed Exposure Pathways
| Name | Source | Environmental Transport and Media | Exposure Point | Exposure Route | Exposed Population | Time Frame |
| Partridge Brook Sediment Pathway | Etching Waste | Stream Sediment | Partridge Brook | Ingestion Dermal |
Waders | Past Present Future |
| Basement Ambient Air Pathway | Solvent Waste | Ambient Air Odors | Basement, Building No. 2 | Inhalation | Former Workers | Past |
| Basement Soil Pathway | Etching Waste | Basement Soil | Basement, Building No. 2 | Dermal Ingestion |
Former Workers | Past |
| Residential Supply Wells Pathway | Solvent Waste | Private Wells | Tap Water | Ingestion Dermal Inhalation |
Residents in this community | Past |
In the following sections, each of these completed exposure pathways of exposure will be outlined in more detail. The public health implications of the exposures will be evaluated in the Discussion section.
(1) Partridge Brook and Sediments Pathway
During the facility operations, wastewater was discharged into Partridge Brook. As a result, elevated concentrations of chromium have been detected in the brook sediments. Therefore, children or adults periodically wading in the brook near the site could have been exposed to contaminants that accumulated in the sediments. The route of exposure would have been ingestion of small amounts of sediment that stuck to a person's hands, ingestion of small amounts of water, and, to a lesser extent, absorption of chemicals through bare skin.
(2) Ambient Air Pathway, Building No. 2 Basement (Past Exposure Only)
Exposure to airborne chemicals represents past exposures only. During past facility operations, wastewater was also discharged into the earthen basement of Building No. 2. During this time, it is presumed that workers were present for some duration in the basement. Therefore, workers in the basement could have been exposed to the VOCs detected in the ambient air.
(3) Metals Exposure, Building No. 2 Basement (Past Exposures Only)
Exposure to metals in the soil represent past exposures only. Metals in the dumped wastewater accumulated in the earthen floor of the basement of Building No. 2. During this time, it is presumed that workers were present in the basement. Therefore, workers in the basement could have been exposed to metals. The route of exposure would have been ingestion and dermal contact.
(4) Residential Supply Wells (Past Exposure Only)
Contaminated water from twenty-seven private wells located near the site represents past exposures only. Since most of the wastes were discharged directly into the onsite soil and the stream, it is highly likely that the contamination of the private wells, and the overburden aquifer, is related to the site. Filtration systems were installed in wells that showed contamination. There are no known water supply wells that have been contaminated that have not had point-of-entry filtration systems installed.
Based on the available sampling data of surrounding private wells, DHHS estimates that approximately three households, prior to April 1999, were exposed to VOCs at levels above their comparison values. Exposure to VOCs occurs by ingestion, through consumption of water, and by dermal contact, through showering or running water. Since those contaminants evaporate into the air from water during showers or baths, people are also exposed through the route of inhalation. Since there are no other known sources of contamination in the area, it is possible to estimate the duration of exposure during the past.
The businesses in Building No. 2 were notified of the contaminants in the site supply well and were advised against drinking water from the tap.
(B) Potential Exposure Pathways
Potential exposure pathways are routes along which exposure could be possible except that one or more of the five critical elements is missing. In some cases, this means that the exposure is not possible now but may be possible if conditions change in the future. In other cases, an exposure may be possible but cannot be confirmed because data are not available. The potential exposure pathways that exist at the former Electro-Sonics site are summarized in the following table.
Potential Exposure Pathways
| Name | Source | Environmental Transport and Media | Exposure Point | Exposure Route | Exposed Population | Time Frame |
| Onsite Trespasser Pathway | Leach field Waste | Contaminated Soil | Onsite, in contaminated soil | Ingestion Dermal Inhalation |
Trespassers on the site | Past Present Future |
| Future Flood Pathway | Solvent, Metals, Petroleum Waste | Partridge Brook | Onsite, in contaminated soil | Ingestion Dermal |
Residents downstream during a flood | Future |
| Onsite Worker Pathway | Solvent Waste | Contaminated Well Water | Onsite, Building No. 2 | Dermal, Inhalation |
Workers at businesses on the site | Past Present Future |
| Future Residential Use Pathway | Solvent Waste | Private Wells | Tap Water | Ingestion Dermal Inhalation |
New Residents | Future |
(1) Future Residential Use Pathway
Areas around the site are zoned for residential use. The site is abutted by residential properties. If new housing were built on nearby properties, the future residents could be exposed to chemicals in the groundwater.
(2) Onsite Worker Pathway
Two businesses currently occupy space in Building No. 2 on the site. Even though employees are supplied with an alternate source of drinking water, it is still possible that exposure could occur if employees use well water while working or when they wash their hands. Therefore, it is not known whether or not contamination is currently affecting people in the building.
(3) Onsite Trespasser Pathway, in Former Leach Field and Alleyway
In the alleyway and leach field, a lens of gravel was used to cover contaminated soil. During the site visit, erosion of the gravel was observed. Footprints were also seen in this area. This indicates that the gravel cover could erode to the point where contaminated soil is exposed. Trespassers could then be exposed to the chemicals in the soil.
(4) Future Flood Pathway
The soil contamination in the leach field and alleyway is less than 100 feet from Partridge Brook. A major flood could push these contaminants into the brook, which would contaminate the stream sediments. Soils in the downstream floodplain of the brook could also become contaminated as a result.
(C) Eliminated Exposure Pathways
DHHS considered four other pathways of concern as eliminated exposure pathways. Exposures through these pathways are not possible. Therefore, these pathways were eliminated from further evaluation.
(1) Private Well Pathway (Present and Future Exposures)
Contaminated water supply wells were fitted with aerated charcoal filtration systems. Wells were re-tested after installation. None of the wells with filtration systems showed any chemical contamination after installation.
Residents with shallow wells or wells upgradient from the site should not be exposed to contaminated groundwater. DES tested several wells in Spofford Village. These wells showed no sign of contamination.
(2) Basement of Building No. 2, Ambient Air and Soil Pathway
Metals and chemicals in the air are still present in the basement of Building No. 2. Access to the basement from inside and outside of the building has been blocked. Therefore, people cannot enter this area to be exposed to contamination.
Eliminated Exposure Pathways
| Name | Source | Environmental Transport and Media | Exposure Point | Exposure Route | Exposed Population | Time Frame |
| Private Well Pathway, Future | Solvent Waste | Private Wells | Tap Water | Ingestion Dermal Inhalation |
Residents in this community | Present Future |
| Basement Soil Pathway | Etching Waste | Basement Soil | Basement, Building No. 2 | Dermal Ingestion |
Present Workers, Trespassers | Present Future |
| Onsite Worker Pathway | Solvent Waste | Contaminated Well Water | Onsite, Building No. 2 | Ingestion | Workers at businesses on the site | Present Future |
| Southern Parcel Pathway | Soil Waste | Contaminated Soil | Onsite, in contaminated soil | Ingestion Dermal |
Trespassers on the site | Past Present Future |
(3) Site Supply Well, Drinking Water Pathway Only
Workers from the businesses in Building No. 2 were provided with a supply of bottled drinking water. Therefore, workers should not be exposed to contaminated groundwater through ingestion.
(4) Southern Parcel, All Areas
Although there has been limited soil testing onsite, no sludge or waste was encountered in the soil borings from the southern parcel. Moreover, while it is known that some chemicals were stored in the buildings on the south parcel, there is no record that wastes were handled or disposed on this area of the site. Therefore, no soil contamination is expected on the southern parcel.
V. DISCUSSION - ADULT AND CHILDREN'S HEALTH ISSUES
Based on the review of environmental data and conditions at the site, there are several completed and potential pathways by which people could be or could have been exposed to chemicals from the site. In the following sections, the public health implications of these exposures will be discussed.
In Section A, the actual or potential exposures to these chemicals will be evaluated using estimates of exposure and the toxicological and epidemiological data available for these chemicals. As part of the ATSDR Child Health Initiative, the susceptibility of young children to the chemical exposures will be a large component of the toxicological review.
Health questions from the community are answered in Section B.
These evaluations provide the weight of evidence to support the DHHS determinations regarding public health hazards associated with exposures.
(A) Public Health Implications of Exposure
In this subsection, we discuss the known adverse health effects that have been associated with the types of exposures that are or were possible at this site. To understand how adverse health effects could be caused by a specific chemical, it is helpful to review factors related to how the body processes such a chemical. Those factors include the exposure concentration (how much), the duration of exposure (how long), the route of exposure (breathing, eating, drinking, and/or skin contact), and the multiplicity of exposure (combinations of contaminants). Once exposure occurs, a person's individual characteristics such as age, gender, diet, general health, lifestyle, and genetics, influence how the body absorbs, distributes, metabolizes, and excretes the chemical. Together these factors determine the potential health effects that can be caused by the chemical.
To evaluate potential health effects, ATSDR has developed Minimal Risk Levels (MRLs) for contaminants commonly found at hazardous waste sites. The MRL is an estimate of daily human exposure to a contaminant that is likely to be without a measurable risk of adverse, non-cancerous effects. MRLs are developed for oral and inhalation exposure routes, and for different durations of exposure (acute: 14 days or fewer; intermediate: 15-364 days; chronic: 365 days or more). Acute MRLs are typically higher than chronic MRLs because of the shorter duration of exposure.
ATSDR publishes MRLs in its series of chemical-specific documents called Toxicological Profile documents that describe health effects, environmental transport, human exposure, and regulatory status of a chemical. The preparers of this Public Health Assessment have reviewed the most recent profiles for the contaminants of concern at the site.
DHHS may also use EPA's chemical specific Reference Doses (RfDs) to determine if non-cancer health effects are possible. RfDs, which are analogous to ATSDR's MRLs, are estimates of daily human exposure to a contaminant that is unlikely to result in adverse non-cancer health effects over a lifetime. For chemicals that are considered to be known, probable, or possible human carcinogens, DHHS uses EPA's chemical-specific cancer potency values to determine a theoretical estimate of excess lifetime cancer risk associated with exposure to the contaminant.
In the following subsections, the completed and potential pathways of exposure will be evaluated in detail.
(1) Completed Exposure Pathways
There are four completed pathways of exposure at the site. These are ways that people have been or are being exposed to contaminants at the site.
(i) Partridge Brook Sediment Pathway
According to the DHHS survey (Appendix D), none of the respondents reported having family members who play or wade in Partridge Brook.
People who wade or play in Partridge Brook could be exposed to site contaminants in sediments. Disturbing the sediment would contaminate the surface water, resulting in further exposure. Someone playing in the brook could be exposed to contaminants in sediment by ingesting small amounts of contaminated sediment on their hands. To a lesser extent, some of the chemicals could also be absorbed through the skin. Adolescents are the most likely population to play or wade in the brook. Therefore, DHHS used exposure parameters for adolescents from EPA and DES guidance documents to estimate their exposure (DES 1998; EPA 1991). These exposures were assumed to occur over a 10-year period of adolescence.
The only chemical of potential concern for people who play or wade in the brook is chromium. For the other chemicals in the sediment, typical exposures would have been less than levels thought to be without risk of adverse effects (e.g., Minimal Risk Levels from ATSDR or Reference Doses from EPA). Table 5 lists a summary of estimated exposures to each contaminant compared to health comparison values.
(a) Chromium
The maximum concentration of chromium detected on the site (3,900 ppm) is buried in the sediments in the area of the brook adjacent to the northern parcel of the site. Exposure to this concentration of chromium would result in an exposure of 1.67x10-5 milligrams per kilogram per day (mg/kg/day), which is well below ATSDR's Minimal Risk Level of 3.0x10-3 mg/kg/day.
Moreover, much of this chromium has probably been reduced from its original hexavalent state to the trivalent state. While the majority of electroplating/etching waste is the hexavalent form (ATSDR 2000), it degrades (a process known as 'reduction') into the less toxic trivalent form (ATSDR Personal Communication 2002). Trivalent chromium has a much higher reference dose and thus it takes a larger dose for a person to experience adverse health effects.
Additionally, hexavalent chromium is not carcinogenic when ingested or absorbed on the skin (ATSDR 2000). Thus, cancer effects as a result of exposure to chromium in Partridge Brook sediments are not expected.
Therefore, people who come in contact with chromium in the sludge while playing or wading in Partridge Brook are not likely to experience any adverse health effects.
(ii) Basement Ambient Air Pathway
(a) 1,1-dichloroethylene
People who worked in the basement of Building No. 2 may have been exposed to VOCs at levels that were similar to levels detected in 1999 (Table 12). People who worked frequently in the basement could have been exposed to VOCs in the air (inhalation). Someone working in the basement could breathe these gases, resulting in exposure. However, these air measurements were taken in 1999, and are used in lieu of a lack of actual air data in the basement while Electro-Sonics was in operation.
The maximum detected level of 1,1-dichloroethylene was above its comparison value (0.036 µg/m3). Inhalation MRLs are expressed in air concentrations (rather than dose). The intermediate MRL for 1,1-dichloroethylene is approximately 79 µg/m3. The maximum detected concentration is nearly 100 times lower than the MRL.
1,1-dichloroethylene is a colorless substance that evaporates at room temperature. It can enter the air as a result of improper waste disposal. Available information indicates prolonged exposure can induce adverse neurological effects and it is possible associated with liver and kidney damage in humans (ATSDR 1996).
This level is above the Cancer Risk Evaluation Guide (0.02 µg/m3). This compound is a Class C, or possible, human carcinogen. There is no direct evidence that 1,1-dichloroethylene causes cancer in humans, although animal studies have shown that increased exposure leads to increased rates of cancer. Mice who inhaled elevated levels of 1,1-dichloroethylene for one year developed kidney cancer.
If a worker spent every day working in the basement of Building No. 2 inhaling the maximum concentration listed in Table 12, it would result in an exposure of 3.32x10-5 mg/kg/day. Using EPA's cancer slope factor, the theoretical cancer risk from inhalation exposure to 1,1-DCE is very small.
Additionally, this exposure scenario is extremely conservative and may not reflect a realistic exposure. It assumes that a worker spent his/her entire workday, continuously for several years, in the basement of Building No. 2, inhaling 1,1-dichloroethylene at the maximum concentration shown in Table 12. Actual exposures may have been much lower.
Therefore, exposures to 1,1-dichloroethylene in the air of the basement of Building No. 2 were unlikely to have resulted in any long-term, serious, adverse health effects in workers in the past. Since these conditions are likely to persist in the future, DHHS recommends that access to the basement continue to be controlled.
(iii) Basement Soil Pathway
People who worked frequently in the basement could have been exposed to chemicals in the soil through ingestion of small amounts of contaminated soil. To a lesser extent, some of the chemicals could also have been absorbed through the skin.
(a) arsenic
Arsenic exceeded its cancer risk comparison value (0.05 ppm). However, the measured concentrations are essentially equal to background levels for these compounds. In New Hampshire, the background concentration of arsenic in soil is 12 ppm (DES 1998). The average arsenic concentration in the surface soil of the basement of Building No. 2 was 10.2 ppm.
(b) benzo[a]pyrene
Benzo[a]pyrene is part of a family of chemicals known as the PAHs. These chemicals comprise a group of over 100 different chemicals that are formed during the incomplete burning of coal, oil, gas, garbage, and other organic substances as diverse as tobacco or charbroiled meat. The background level for total PAHs (i.e., the sum of the individual PAH compounds) is 25 ppm for urban areas in New England (Bradley et al. 1994). The maximum concentration of total PAHs in the basement was lower than this background level.
(c) lead
The maximum concentration of lead (30,000 ppm) was above the EPA's industrial screening level (750 ppm). As well, the average concentration of lead in the basement soil (2,706 ppm) exceeded this screening level. Using EPA's Adult Lead Model, it is estimated that a typical adult exposed at this level would have a greater than 18% probability of having blood lead levels greater than 10 micrograms per deciliter (µg/dL) of blood. This model includes inhalation of lead-contaminated soil.
Lead is a compound that cannot be broken down and persists in the body. Shortly after lead enters the body, it travels in the blood to the "soft tissues" (such as the liver, kidneys, lungs, brain, spleen, muscles, and heart). After several weeks, most of the lead moves into the bones and teeth. In adults, about 94% of the total amount of lead in the body is contained in the bones and teeth. Some of the lead can be stored in bones for decades; however, some lead can leave the bones and reenter the blood and organs under certain circumstances. For example, lead can re-enter the blood during pregnancy and periods of breast feeding, after a bone is broken, and during advancing age.
The main target for lead toxicity is the nervous system, both in adults and in children. Long-term exposure of adults to lead at work has resulted in decreased performance in some tests that measure functions of the nervous system. Lead exposure may also cause weakness in fingers, wrists, or ankles. Some studies in humans have suggested that lead exposure may increase blood pressure, though the evidence is inconclusive. Lead exposure may also cause anemia, a low number of blood cells. The connection between the occurrence of some of these effects (e.g., increased blood pressure, altered function of the nervous system) and low levels of exposure to lead is not certain. At high levels of exposure, lead can severely damage the brain and kidneys in adults or children. In pregnant women, high levels of exposure to lead may cause miscarriage. High-level exposure in men can damage the organs responsible for sperm production.
There is little evidence that lead causes cancer in humans. Kidney tumors have developed in rats and mice given large doses of lead. These results of these high-dose studies are not sufficient to predict whether lead may cause cancer in humans. ATSDR has determined that lead acetate and lead phosphate may reasonably be expected to be capable of causing cancer, based on sufficient evidence from animal studies, but there is also inadequate evidence from human studies. Neither of these lead compounds (lead acetate and lead phosphate) were detected in soil samples taken from the basement of Building No. 2.
Again, this model for worker lead exposure is very conservative since it assumes that a worker spends his/her entire workday, continuously for several years, in the basement of Building No. 2. Actual exposures may have been much lower since it is likely that workers were not exclusively in the basement. Therefore, it is unlikely that spending small amounts of time in the basement would have resulted in long-term, adverse health effects.
(iv) Residential Supply Wells
Currently, plumes of groundwater contamination in the vicinity of the site are not impacting any private residential drinking water wells. Since 2000, all susceptible wells in the area have been routinely tested by DES, and contaminated wells have been fitted with filtration systems.
It is not known when exposure to chlorinated VOCs in Residential Well Nos. 1, 2 and 3 (the wells with chemicals above the comparison values) began. No well sampling data were available before initial tests in 1998. Upon discovery of the contamination in residential wells, DES provided the residents of affected wells with aerated charcoal filtration systems. This action stopped exposure to chlorinated VOCs at concentrations of as high as 1,600 ppb.
Since there are no data on VOC contamination in the residential wells before 1998, exposures to VOCs earlier than this date are unknown. To account for this uncertainty, DHHS used very conservative assumptions about VOC concentrations and duration in its evaluation of past exposures to TCE in the residential water supplies:
While there are uncertainties about exposures before 1998, DHHS chose to be protective of public health by making conservative assumptions about the ways people may have been exposed in the past. These conservative assumptions likely overestimated actual exposures to VOCs. DHHS compared the estimated exposure levels with available health guidelines, comparison values and information from the scientific literature regarding the health effects from exposure to VOCs to assess the likelihood of adverse health effects.
DHHS methodology is consistent with the approach used by other public health agencies in its estimation of exposures to hazardous substances. To be more concise for the general public, a detailed explanation of the assumptions and calculations used to estimate exposures and determine the likelihood of adverse health effects is not presented in this document, but is available upon request.
(a) Duration and Levels of Exposure - Residential Wells
Four wells had levels of VOCs above the initial comparison values. To determine the extent of exposure, DHHS developed a model that accounts for all pathways of exposure (oral, skin and inhalation). Again, DHHS assumes very conservative assumptions about the factors (e.g., duration) that account for the amount of exposure. When calculating a dose for a particular well, the maximum documented level of contamination was used. DHHS assumed that these levels of contamination were present since 1966, when use of VOCs on the site began.
Not all residents were exposed to contaminated well water for the presumed maximum duration of exposure (assumed to be 35 years, from 1966 through 2001). To account for exposures for those residents who may have moved to or away from Spofford Village during this 35 year period, DHHS used 9 years as the alternative duration of exposure (the median time in one residence; EPA 1997). Additionally, DHHS listed two separate exposures for both the 9-year and 35-year scenarios: One is to reflect exposure in adults and the other is to reflect exposure in children. In the 35-year scenario for children, the model was adjusted to take into account that exposure as a child could only take place for the first 17 years of exposure. The estimated exposures for these residential wells can be found in Tables 14a and 14b.
Additionally, if a compound is a carcinogen, DHHS evaluated the possibility of increased cancer risk.
(b) 1,1-dichloroethane - Residential Well Pathway
Although there are no studies in humans, there is limited data available in most animals indicating that it is less toxic than other chlorinated VOCs (ATSDR 1990b). The available data in animals suggest that inhaled 1,1-dichloroethane (1,1-DCA) may be toxic to the kidneys. However, this finding is limited to one species (cats) and was not observed in three other species tested under the same conditions. Additionally, these toxic effects on the kidneys were only observed after lethal doses were given (Plaa and Larson 1965). Another effect observed in animals but not humans following inhalation exposure to 1,1-DCA is fetotoxicity, or adverse effects on developing fetuses (ATSDR 1990b).
ATSDR has not developed any comparison values for 1,1-dichloroethane. However, EPA has derived an RfD of 0.1 mg/kg/day. This was based on a 13-week inhalation study in rats (Hofman et al. 1971). A 1,000-fold safety factor has been applied to account for extrapolation from animal to human exposures. The "no effect" level is 115 mg/kg/day (RAIS 1994), over 1,000-fold higher than the reference dose and 10,000-fold higher than the highest dose seen in Residential Well No. 1 (0.0138 mg/kg/day). Therefore, it is unlikely that these exposures to 1,1-dichloroethane will result in adverse health effects.
There is inconclusive evidence that 1,1-DCA is carcinogenic in humans. Results of a drinking water study in mice indicated that 1,1-DCA is not carcinogenic (Klaunig et al. 1986). Another experiment using human cells also yielded negative results in terms of cancer (Herren-Freund and Pereira 1986). Therefore, there is no theoretical cancer risk from exposures to 1,1-DCA in Residential Well Nos. 1, 2 or 3.
(c) 1,1-dichloroethylene - Residential Well Pathway
Limited information is available on the human health effect following exposure to 1,1-dichloroethylene (1,1-DCE). In humans, chronic exposure to 1,1-DCE is associated with liver and kidney toxicity (ATSDR 1994b).
Groups of people who should be specifically cautioned against exposure to 1,1-dichloroethylene include the very young, the elderly, pregnant women, those who ingest alcohol, people using phenobarbital (or possibly other hepatic enzyme-inducing drugs), people who are fasting, and those with organ (heart, liver, kidney and central nervous system) dysfunctions (ATSDR 1994b).
An MRL of 0.009 mg/kg/day has been derived for chronic-duration oral exposure to 1,1-DCE. This MRL is based on changes in the livers of rats exposed to 9 mg/kg/day (Quast et al. 1983). Since the highest estimated exposure (0.000441 mg/kg/day) is 20-fold lower than the MRL calculated with a 1,000-fold uncertainty factor, it is unlikely that anyone would experience adverse non-cancer health effects from the levels of 1,1-DCE in Residential Well Nos. 1, 2 and 3.
The evidence for 1,1-DCE carcinogenicity is inadequate in humans and is limited in animals. EPA's cancer slope factor for this chemical was derived from a study in which rats were exposed to 1,1-DCE in drinking water. A 10-fold uncertainty factor was used, meaning that a high-dose exposure is more likely to produce carcinogenic effects than a low-dose exposure. Regardless, using EPA's cancer slope factor derived from the high-dose study, the theoretical cancer risk from exposure to 1,1-DCE is a low for Residential Wells Nos. 1 and 2. The theoretical risk from exposure to 1,1-DCE for Residential Well No. 3 appears to be near background levels.
(d) cis-1,2-dichloroethylene - Residential Well Pathway
The most significant effects of cis-1,2-DCE exposure are on the blood and the liver. ATSDR has derived an MRL for cis-1,2-DCE for intermediate exposures, 0.2 mg/kg/day. This was based on a laboratory study that observed changes in the proportions of cell types in the blood of rats and liver effects in mice at doses as low as 97 mg/kg/day. No effects were observed in the animals at 17 mg/kg/day. Other organs and endpoints were an order of magnitude less sensitive (ATSDR 1996). The estimated exposure to 1,2-DCE from Residential Well No. 1 was 100 times less than the level at which no effect was observed in the animal studies.
EPA has derived an RfD for cis-1,2-DCE of 0.01 mg/kg/day. This is based on the same study that ATSDR used for the intermediate MRL and differs only in that an additional 20-fold safety factor has been applied to account for extrapolation from intermediate to chronic exposures. The estimated exposures were also less than this RfD but still were more than 100 times less than the "no effect" level from the study on which it is based. Therefore, it is unlikely that these exposures will result in adverse health effects.
Tests on the ability of cis-1,2-DCE to damage genetic material, which could initiate cancerous growths, have been predominantly negative. Federal and international agencies have given 1,2-dichloroethylene a non-cancer rating or a "not classifiable" rating in terms of carcinogenicity (ATSDR 1996).
(e) trichloroethylene - Residential Well Pathway
Most of the information regarding the effects of TCE in humans comes from case studies and experiments describing the effects of TCE after inhalation exposure. These studies indicate that the primary target of TCE in humans is the central nervous system (ATSDR 1997a). Speech impairment, hearing impairment, and stroke have been observed to be more prevalent among people enrolled in ATSDR's National Exposure Sub-registry for TCE (ATSDR 1999b; Burg and Gist 1999).
ATSDR has not derived an MRL for chronic exposures to TCE because suitable studies are not available. However, 0.2 mg/kg/day have been established as the MRL for acute exposures (fewer than 14 days). This MRL is based on a study where mouse pups were exposed to TCE and exhibited behavioral changes later in life. The lowest exposure at which this effect was observed was 50 mg/kg/day (ATSDR 1997a). Estimated exposures to TCE in the drinking water wells fell in the range of 0.00000571-0.00145 mg/kg/day, which are a 1000- to 100,000-fold lower than the level at which non-cancer effects were observed in the animal studies.
Animal studies indicate that effects of the liver are also possible following TCE exposure. In the liver, TCE is broken down to different metabolites, including trichloracetic acid, which can damage the liver tissues (Lash et al. 2000). A recent reassessment of non-cancer toxicity of TCE suggests that an exposure level that would be without effects on the liver would be in the range of 0.06-0.12 mg/kg/day (Barton and Clewell 2000). The estimated exposures from the drinking water wells are below this range.
NTP recently classified TCE as being reasonably anticipated to be a human carcinogen (NTP 2000). Moreover, a recent analysis of TCE carcinogenicity suggests a stronger association between occupational exposures to TCE and liver and kidney cancer than previous analyses (Wartenberg et al. 2000). The review also suggests associations between TCE and both Hodgkins disease and non-Hodgkins lymphoma. Laboratory studies with animals have observed similar cancer primary sites as in humans (e.g., kidney and liver).
EPA's cancer slope factor for this chemical was derived from animal studies. However, using the latest available cancer slope factor for TCE, it appears that there would be a low theoretical risk of developing cancer from this drinking water exposure in Residential Well Nos. 1 and 2. The theoretical risk for Residential Well No. 3 appears to be much lower than the risk associated with wells No. 1 and No. 2.
(f) Vinyl Chloride - Residential Well Pathway
Vinyl chloride was detected in December 1999 in several drinking water wells near the site. Residential Well Nos. 1, 2 and 3 contained levels of vinyl chloride (53.0, 35.0 and 0.62 ppb) above the cancer and non-cancer comparison values (30 and 0.05 ppb, respectively). The date that this vinyl chloride contamination began is uncertain. The concentrations in these three wells showed no pattern of increasing or decreasing over the period that they were monitored by DES.
Workers who have been exposed to vinyl chloride at high concentrations developed signs and symptoms of intoxication such as dizziness, drowsiness, and/or headache. These high level exposures may also produce lung and kidney irritation and inhibition of blood clotting. Long-term exposure of humans in occupational settings has been associated with the development of a number of other toxic effects. The most sensitive effects are changes in the tissues of the liver (ATSDR 1997c).
ATSDR has derived a chronic MRL for vinyl chloride of 0.00002 mg/kg/day. This is based on a study that observed changes in the liver cells of rats at an exposure dose of 0.018 mg/kg/day (ATSDR 1997c). All estimated exposures from Residential Well Nos. 1 and 2 are higher than the MRL and they approach the level at which effects were observed in animals. Given that effects on the liver have been demonstrated in humans and animals, there is little evidence for large differences between the species in terms of toxicity (ATSDR 1997c). Therefore, these exposures, if they lasted as long as possible (35 years), could cause effects on the liver for some people who drank and used water from Residential Well Nos. 1 and 2. Exposures to the levels observed in Residential Well No. 3 were much lower and no adverse effects are expected.
A large number of occupational studies have reported a greater than expected incidence of a rare type of cancer, angiosarcoma of the liver, among workers exposed to vinyl chloride. Other types of cancer that have shown a statistically significant increase in incidence among vinyl chloride workers, at least in some studies, include cancer of the brain and central nervous system, the lung and respiratory tract, and the lymphatic/hematopoietic system. Angiosarcoma has also been observed in laboratory studies with animals. Therefore, vinyl chloride is considered a known human carcinogen, with angiosarcoma of the liver as the primary site of concern (ATSDR 1997c). For a person exposed to Residential Well Nos. 1 and 2, for 35 years (the longest assumed duration of exposure for a resident), there would be an increased theoretical risk of developing cancer (an increased risk of 1:1,000). Cancer risk for the 9-year exposure model is somewhat lower (1:10,000), but still represents a moderate risk. For Residential Well No. 3, levels of vinyl chloride are significantly lower (0.62 ppb) than Nos. 1 and 2, and the risk increased theoretical risk drops down to levels where it is barely above background levels. (1:1,000,000)
Data suggest that the following subsets of the human population may be more susceptible to the toxic effects of vinyl chloride: fetuses; infants; young children; people with liver disease, irregular heart rhythms, impaired peripheral circulation, or systemic sclerosis. Other factors that may exacerbate the effects of vinyl chloride are exposure to organochlorine pesticides, consumption of alcoholic beverages, and the use of barbiturates (ATSDR 1997c).
The exposure calculations, as well as the estimation for the lifetime elevated risk of cancer, take into consideration all possible pathways of exposure to the contaminated well water (including drinking, inhaling and skin contact) and assumes upper bound estimates for exposure factors (e.g., amount of water consumed daily, duration of showers). This calculation is not an indication of a real-life increase in cancer to those who were exposed to vinyl chloride, it is evidence of a potential added risk, suggesting a difference between the cancer incidence under the exposure conditions and the background incidence in the absence of exposure (EPA 1993). The actual risk for any one person getting cancer is probably lower than the calculated risk.
(g) Combined Effects of Chemicals with Similar Toxicological Properties - Residential Well Pathway
The five chemicals for which there was exposure from contaminated wells can be grouped into two subsets with similar toxicological properties.
TCE and 1,2-DCE are metabolized by the body in much the same way. For low-level exposures, they break down to trichloroacetic acid and dichloroacetic acid, which are thought to induce effects on the liver. TCE is detoxified by the glutathione transferase pathway at higher exposures. Metabolites from this pathway (e.g., S-[1,2-dichlorovinyl]-L-cysteine or DCVC) have been associated with kidney tumors.
One well contained both TCE and 1,2-DCE above comparison values. The combined exposure for an adult for 35 years, from both chemicals, was 0.00638 mg/kg/day. The lowest RfD or MRL for both compounds is the RfD for 1,2-DCE of 0.01 mg/kg/day. This combined exposure to TCE and 1,2-DCE was not greater than the RfD for 1,2-DCE. These comparison values are commonly derived from animal studies. Humans are less likely to experience these effects than laboratory animals due to a different metabolism. Therefore, the combined exposures to TCE and 1,2-DCE are not likely to result in adverse health effects in humans.
Regarding cancerous effects, TCE appears to be carcinogenic based on animal studies. 1,2-DCE is not considered carcinogenic. Therefore, the theoretical excess risks of developing cancer should not increase when these chemicals are mixed.
Vinyl chloride has unique toxicological properties but can also be influenced by the toxic effects of other chemicals. For example, since it is the metabolites of vinyl chloride that are toxic, the effects of vinyl chloride can be increased by speeding up its metabolism. The metabolic pathway responsible for breaking down vinyl chloride is inducible by exposures to organochlorine pesticides and Arochlor 1254 (PCBs) (ATSDR 1997c). Therefore, someone who is exposed to vinyl chloride and pesticides may experience greater effects than someone who is exposed to vinyl chloride alone. It is possible that exposures to other solvents that are metabolized by this pathway (e.g., tetrachloroethylene, TCE, 1,2-DCE) could have a similar effect. However, 1,2-DCE metabolites have been shown to inhibit metabolic activity (ATSDR 1996). Therefore, the combined effects of other solvents with vinyl chloride are equivocal.
(h) Children's Susceptibility - Residential Well Pathway
Children differ from adults in their physiology (e.g., respiratory rates relative to body weight), pharmacokinetics (i.e., distribution, absorption, metabolism, and excretion of a chemical), and pharmacodynamics (i.e., susceptibility of an organ to the exposure) (Pastino et al. 2000). Therefore, when evaluating chemical exposures, it is important to consider whether children would be more or less susceptible to the effects of the exposure than adults.
For TCE and 1,2-DCE, there is evidence that children are more susceptible to exposures than adults. The most sensitive stage of childhood appears to be in utero (i.e., during pregnancy) and during the first year of life. During this time, the primary enzyme that breaks TCE as well as 80 other chemicals down to its toxic metabolites (the CYP2E1 isoform of cytochrome P-450) may be active, but other systems of detoxification and excretion are still developing (Pastino et al. 2000). This could result in higher internal doses of the toxic intermediates at the target organs for children than adults.
In addition to the toxicological evidence, recent epidemiological studies suggest that exposures to TCE or 1,2-DCE during pregnancy could result in adverse health effects for the developing fetus. One study in New Jersey found that maternal residence during pregnancy in areas with perchlorethylene (PCE), TCE, or DCE-contaminated drinking water was associated with an increased risk of birth defects of the CNS, the neural tube, and the oral cleft (Bove et al. 1995). An ATSDR study of the U.S. Marine Corps Base at Camp LeJeune in North Carolina reported significantly decreased mean birth weight for babies born following maternal exposures to VOCs during pregnancy (ATSDR 1997b). A study of childhood leukemia conducted in Woburn, Massachusetts, concluded that the incidence of childhood leukemia was associated with the mother's potential for exposure to water from specific wells contaminated with PCE and TCE, particularly exposure during pregnancy (MDPH 1997). Another study in New Jersey found a statistically elevated rate of childhood leukemia in towns served by community water supplies contaminated with TCE and tetrachloroethylene in the years 1979 to 1987, compared to towns without a history of such contamination (Cohn et al. 1994). Finally, a study in Arizona observed an increase in the proportion of live births with congenital heart defects following maternal exposure to TCE in drinking water (Goldberg et al. 1990). Overall, the associations drawn from these limited epidemiological studies of humans are suggestive, yet inconclusive, that exposure to these VOCs (TCE and DCE) through drinking water may cause birth defects or childhood leukemia in children exposed while a fetus.
Vinyl chloride has the potential to affect fetuses and young children more seriously than adults for the same reasons that TCE and 1,2-DCE are of concern for very young children. Vinyl chloride can cross the placental barrier and enter the blood of the fetus (ATSDR 1997c). Animal studies have shown that subjects exposed before adolescence or during pregnancy may have a greater death rate and increased likelihood of developing cancer than adult animals exposed for similar periods. However, this may simply reflect that younger animals have a longer time for the effects of the exposure to be manifested, not increased sensitivity (ATSDR 1997c).
The susceptibility of children to toxic chemicals is a new field of research so precise estimates of increased risk for developmental effects are not available. If young children or pregnant women resided in the homes with contaminated wells, there is a chance that exposures to TCE, and 1,2-DCE and vinyl chloride could have affected the health of the children or developing fetuses. The homes with the highest contamination and, hence, the greatest risk were Well Nos. 1 and 2.
(2) Potential Exposure Pathways
DHHS has identified three potential pathways of exposure at the site. These are ways that people might be or might have been exposed to contaminants; however, either conclusive evidence of exposure is lacking or the exposure has not yet occurred.
(i) Onsite Trespasser Pathway
One-third of the community members who completed the DHHS survey indicated that they walk on the former Electro-Sonics site (Appendix E).
Someone walking (trespassing) on the site could be exposed to contaminants in soil by ingesting small amounts of contaminated soil or waste on their hands. To a lesser extent, some of the chemicals could also be absorbed through the skin. Adolescents are the most likely population to trespass on the site.
While there is evidence of trespassing, there is no evidence of contamination in the surface of the soil. Previous oil spills may have contaminated the soil around the site. The test pits (Table 4) and soil gas samples (Table 3) from the area of the subsurface leach field and alleyway indicate contamination below the surface of the soil. As a protective measure, DES placed a layer of gravel over this area. It is unlikely that this layer of gravel will serve as a permanent barrier to exposure. During the site visit, there were signs of gullying and erosion of the gravel.
Therefore, trespassing on the site could become a public health concern if the chemicals in the soil became uncovered.
(ii) Future Flood Pathway
The contamination in the former subsurface leach field and adjacent alleyway is less than 50 feet from Partridge Brook. Previous oil spills may have contaminated the soil around the site. If a flood were to occur, the contaminated soil could be washed into the brook. This would lead to increased exposures to contaminants in the sediments and water. Also, contamination would be deposited in presently uncontaminated areas across the floodplain.
Therefore, a future flood event could create a public health concern in flood waters uncover or redistribute contamination.
(iii) Onsite worker pathway
Two known businesses, with at least 6 workers, occupy Building No. 2. The site supply well contained many chemicals above their respective drinking water comparison values. Although exposure through drinking water from the site supply well is not a completed exposure pathway, it is not clear if workers engage in other activities that may expose them to the chemicals from this well.
Using a hand-washing model developed by EPA, DHHS determined the dose from all 13 chemicals that were above their respective drinking water comparison value. This model estimates how much of a chemical is absorbed through the skin during a routine hand washing. These doses were then compared to the corresponding MRL. Although the MRL accounts for health effects from oral exposure (i.e., drinking), the MRL can still be used and is a more conservative value (ATSDR Personal Communication 2002).
According to the hand washing model, doses from all chemicals of concern from the site supply well were below the corresponding MRLs (Tables 7a & 7b). Although there is some exposure to these chemicals, the dose is extremely low since exposure duration is brief and a relatively small amount of skin is exposed to the chemicals.
Therefore, exposure to chemicals through the washing of hands is not expected to result in adverse health effects.
It is not known if workers in Building No. 2 use the site supply water for purposes other than hand washing. DES has informed the site owner and workers in the building of contamination, so it is possible that employees avoid use of this water supply altogether.
Excessive use of water from the site supply well could result adverse health effects.
(3) ATSDR Child Health Initiative
Children are at a greater risk than adults from certain kinds of exposure to hazardous substances released from waste sites. They are more likely to be exposed for several reasons (e.g., they play outdoors more often than adults, thus increasing the likelihood that they will come into contact with chemicals in the environment). Due to their smaller stature, children may breathe dust, soil, and heavy vapors close to the ground. Children are also smaller, resulting in higher doses of chemical exposure per body weight. The developing body systems of children can sustain permanent damage if certain toxic exposures occur during critical growth stages. Most importantly, children depend completely on adults for risk identification and management decisions, housing decisions, and access to medical care.
At the former Electro-Sonics site, children are more likely to be exposed to contaminants because children, not adults, are more likely to trespass on the site. To account for this, DHHS used exposure factors for children/adolescents when estimating exposure for people who trespass on the site or who play in Partridge Brook near the site.
Child exposure was also considered when evaluating past exposure to VOCs in residential wells. Children are smaller, and their bodyweight is less than that of an adult. Also, since children are smaller than adults, they tend to drink less water. These factors were taken into consideration when estimating exposures.
When performing any public health assessment, DHHS gathers health concerns from people living in the vicinity of the site. The health concerns that people express are then used to direct the focus of the Public Health Assessment so that questions from the community are answered. At the former Electro-Sonics site, DHHS accomplished this task through four activities:
Based on responses from the written survey and the availability session, the key findings of the community outreach program were:
A Public Health Assessment contains information on: (1) the site contaminants and possible exposure routes; (2) the extent of contamination; and (3) the adverse health effects that have been associated with exposures to the types of chemicals present.
The following is a list of questions from the written survey and public availability session on other topics not already addressed in the document. Since health concerns shared in either the survey or availability session is considered confidential, all comments have been paraphrased to protect the identity of the respondent.
(1) List of Other Health Concerns or Questions
1. Can exposure to the chemicals on the site cause depression, skin rashes or hives?
While these issues are important, in general they are considered symptoms of many other types of conditions and not specific disease in themselves. The effects of exposure from site contaminants cannot be evaluated separately from the other causes of these general symptoms.
2. Can the oil spill that occurred 3 to 5 years ago cause people harm?
According to discussions with DES, it is unlikely that people were actually exposed to oil when it was released to the brook from the site several years ago. The public health assessment evaluates the risk to human health associated with contaminants present at the site and in Partridge Brook surface water and sediment. One of the Public Health Assessment's conclusions is that current exposure to contaminants in Partridge Brook does not present a significant health risk.
3. In the future, will well water be contaminated?
DES' hydrogeological investigation at the former Electro-Sonics facility, which included sampling of some 26 residential bedrock drinking water wells, indicated that the contaminated groundwater plume appears to be stationary and is not moving. In addition, it appears that the levels of contaminants present in the groundwater are decreasing with time. The DES Site Manager can provide additional information about this concern.
4. Will our water supply be continually monitored?
DHHS recommends occasional monitoring of the groundwater, especially affected private wells or wells with the potential to become contaminated. We provide our recommendations to regulatory agencies and the responsible party, but have no authority to require that they be implemented.
5. Will the site be cleaned up? When?
New Hampshire Department of Environmental Services (DES) and the U.S. Environmental Protection Agency are currently planning a strategy to clean up the site. For information on this process and on proposed plans for the site, we recommend that you contact John F. Liptak at 603-271-1169.
6. Will the buildings on the site be protected because of historical significance if the site is cleaned up?
When petitioned to do so by concerned individuals/groups, the EPA takes historical buildings into consideration.
There is widespread contamination underneath Building No. 2. Due to its age and state of disrepair, this building will likely be removed once a removal action takes place.
Health outcome data were not evaluated for this site because the population of concern is very small. Large study populations are usually necessary to provide significant health outcome statistics. As a result, it would be very unlikely that any health effects associated with the site could be detected through a health outcome data review.
The State of New Hampshire maintains a cancer registry for cancer incidences. Information from the New Hampshire State Cancer Registry is available for the years 1987 through 1999. The 1999 Cancer in New Hampshire Report is available to the public and can be obtained by contacting DHHS (Appendix H).
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