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PUBLIC HEALTH ASSESSMENT

SAVAGE MUNICIPAL WATER SUPPLY
MILFORD, HILLSBOROUGH COUNTY, NEW HAMPSHIRE

ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

To identify possible facilities that could contribute to the air, surface water, and soil contamination near the Savage Water Supply site, ATSDR searched the 1997, 1988, and 1989 Toxic Chemical Release Inventory (TRI). TRI is developed by EPA from the chemical release (air, water, and soil) information provided by certain industries. Within the town of Milford, the 1988 and 1989 TRI indicated that Hitchiner released trichloroethane into ambient air at a rate of about 50,000 and 110,906 lbs/year, respectively.

A. ON-SITE CONTAMINATION

Appendix III summarizes the levels of contamination present in on-site media. On-site contamination consists of contaminants and contaminant sources situated on the properties of the four PRPs (Hendrix, Hitchiner, NESFAB, and OK Tool) as previously indicated. These four industries have been identified by EPA as potential sources of contaminants detected in the Savage Municipal Well and in the immediate vicinity of the site. Contaminants that have been detected are VOCs, acid and base/neutral extractable compounds (ABNs), metals, PAHs, and PCBs. These contaminants have been found in groundwater, surface water, sediment, and soil located on-site. Ambient air sampling was also conducted on-site in 1988 to determine if VOCs were being released to the air from the site. Sampling of surface water and groundwater by the NH WSPCC indicated that contamination was widespread throughout the area of the site.

On-site sampling has been conducted in conjunction with the RI and the NH WSPCC hydrogeological investigation. High concentrations of the VOCs 1,1-dichloroethane, 1,2-dichlo-roethylene, 1,1,1-trichloroethane, tetrachloroethylene, and trichloroethylene have been detected in on-site groundwater with maximum levels totaling over 9,000 ppb. Elevated levels of 1,1,1-trichloroethane, benzene, and tetrachloroethylene have been found in surface water on-site. Sediment samples taken on-site contained elevated levels of PAHs, PCBs, and metals including chromium (total) and lead. Soil samples were taken in thirteen areas located on-site in July of 1989. High concentrations of PCBs, 1,1-dichloroethylene, 1,2-dichloroethylene, 1,1,1-trichlo-roethane, tetrachloroethylene, and trichloroethylene were found in these samples. Elevated levels of the metals arsenic, chromium (total), and lead were also detected. Ambient air was sampled on-site between August 1988 and November 1988 with only slightly elevated concentrations of VOCs being present.

B. OFF-SITE CONTAMINATION

Appendix IV summarizes the levels of contaminants present in off-site media. Off-site contamination consists of contaminants detected in the areas surrounding the site and included VOCs, ABNs, metals, PAHs, and PCBs. These contaminants were found in groundwater, surface water, sediment, and soil located off-site. Ambient air sampling for VOCs was conducted in 1988. Sampling of groundwater and surface water by the NH WSPCC indicated that contamination was widespread throughout the areas surrounding the site.

Off-site sampling was conducted in conjunction with the RI and the NH WSPCC hydrogeological investigation. Contaminants and maximum concentrations detected in the Savage Municipal Well in February 1983 were tetrachloroethylene (greater than 3,981 ppb), 1,1,1-trichloroethane (1,720 ppb), 1,2-dichloroethylene (280 ppb), and trichloroethylene (244 ppb). Similar levels were detected at this time in a well serving the Milford Mobile Home Park. Contamination has been detected in groundwater monitoring wells, 1,100 feet east (downgradient) of the Savage Municipal Well. Contamination has also been detected in the Keyes Municipal Well, another well serving the Town of Milford, located approximately two and a half miles east of the Savage Municipal Well. The Savage Municipal Water Supply Site is not believed to be the source of this contamination.

High concentrations of 1,1-dichloroethylene, benzene, 1,2-dichlo-roethylene, 1,1,1-trichloroethane, tetrachloroethylene, trichloroethylene, vinyl chloride, bis(2-ethylhexyl)phthalate, arsenic, chromium, and lead have been detected in off-site groundwater. Elevated levels of 1,2-dichloroethylene, 1,1,1-trichloroethane, and tetrachloroethylene have been found in surface water off-site. Sediment samples taken off-site contained elevated levels of PAHs and metals including arsenic and lead. High concentrations of PCBs and chromium (total) were found in soil samples taken off-site. In August of 1988, VOCs were detected at concentrations above background levels, in ambient air samples taken off-site along portions of the Hitchiner-Hendrix discharge stream.

Appendix V summarizes the levels of contaminants that were detected in six private residential drinking water supply wells. This contamination was reported in the NH WSPCC hydrogeological investigation and included 1,2-dichloroethylene, tetrachloro-ethylene, and trichloroethylene at maximum concentrations totaling over 3,600 ppb in these water supply wells (4). No known sampling of residential wells for metals has been performed to date.

C. QUALITY ASSURANCE AND QUALITY CONTROL

This interim public health assessment is based on data contained within the 1985 hydrogeological investigation (4) and the 1989 draft RI (1). It is assumed that the samples generated in these investigations were handled properly and the resulting analytical data have been validated by a QA/QC review. The accuracy of the conclusions and recommendations contained within this interim public health assessment is determined by the availability and reliability of the data.

D. PHYSICAL AND OTHER HAZARDS

The only physical hazards identified on-site are the buildings situated on the properties of the four industries and a small open discharge pond located on the Hitchiner property, south of Route 101A, at the beginning of the Hitchiner-Hendrix discharge stream.

PATHWAYS ANALYSES

A. ENVIRONMENTAL PATHWAYS (FATE AND TRANSPORT)

As a result of past disposal practices by the four industries identified by EPA as PRPs, there are numerous potential sources of on-site contamination (see Background Section). Based on the available monitoring data and disposal records, the current principal sources of on-site contamination are:

  1. Past disposal of liquid wastes into the drain system and on the ground outside of the Hendrix facility. Discharge of contact cooling water to the Hitchiner-Hendrix discharge stream, prior to March 1990, when a closed loop water system was instituted at Hendrix.
  2. A vapor degreaser and two dip tanks, in which VOCs were used, located near floor drains and connected to the surface water discharge system at the Hitchiner facility. Discharge of non-contact cooling and process water into the Hitchiner- Hendrix discharge stream, prior to 1980, when Hitchiner instituted a pretreatment program for its wastewater discharge.
  3. Past discharge of several thousand gallons of a mixture of VOCs and paint sludges from an inground storage tank to a gravel area behind the NESFAB facility.
  4. Past discharge of VOCs, including tetrachloroethylene, from a vapor degreasing tank to a floor drain at the OK Tool facility. Disposal of oily and liquid wastes onto the grounds on the north side of the OK Tool property. Discharge of process cooling water from OK Tool into the Souhegan River.

The principal pathways of contaminant migration from the site include:

  1. Direct discharge of contaminants to the soil (via building floor drains) and the Hitchiner-Hendrix discharge stream from both the Hitchiner and Hendrix facilities.
  2. Leaching of contaminants from soils near the OK Tool and NESFAB facilities into groundwater around the site.
  3. Discharge of contaminated groundwater to the Souhegan River, migration of contaminated surface discharge to the Souhegan River, and uptake of contaminated groundwater by agricultural crops.
  4. Release of vapors and fugitive dusts from on-site soils to ambient air.

GROUNDWATER

The major pathway for movement of contaminants from the site is by groundwater migration. Groundwater in the area of the site flows in an easterly direction past the OK Tool, Hitchiner, and Hendrix properties, and towards the Savage Municipal Well (see Appendix VI). A numerical model was used by the NH WSPCC in their hydrogeologic study to simulate the pumping of the Savage Municipal Well. Their results indicated that the well would draw in groundwater from thousands of feet away from the west and southwest. The Savage Municipal Water Supply Site lies in the Souhegan River drainage basin and is underlain by an extensive unconfined high yield sand and gravel aquifer. Two tributaries to the Souhegan River in the site area are Tucker Brook and the Hitchiner-Hendrix discharge stream. This discharge stream is perched and recharges the groundwater in its vicinity. The Souhegan River recharges the aquifer in the western portion of the site near the OK Tool property and the river receives groundwater from the aquifer further downstream. The operation of production wells at the Hitchiner and Hendrix facilities has a significant effect upon the groundwater flow of the aquifer in the immediate site vicinity. Groundwater flow in the area is also influenced to some degree by the two active Milford Fish Hatchery production wells located on the north side of the Souhegan River. The groundwater west of the Milford Drive-In Theater access road and north of Route 101A flows in an east/southeast direction due to the recharging of the Souhegan River and the two industrial production wells. On the east side of the Drive-In Theater access road the groundwater changes flow to a northeasterly direction toward the Souhegan River.

VOC contamination has been detected in groundwater down to bedrock. Migration of contaminants in groundwater has been determined from the properties of the four PRPs eastward along Route 101A and northward to the Souheagan River. The extent of contaminant migration along the eastern portion of the contaminant plume is still being determined, with the sampling of additional monitoring wells, which were installed in 1989. The highest concentrations of VOCs in groundwater have been detected in monitoring wells located to the east and immediately downgradient of the OK Tool property (see Appendix I). The predominant VOC contaminants at the Savage Municipal Water Supply Site are 1,2-dichloroethylene, 1,1,1-trichloroethane, tetrachlo-roethylene, and trichloroethylene. In general, these compounds are colorless, highly volatile, heavier than water and moderately to highly soluble in water. These VOCs would be expected to have a high mobility in the groundwater due to their low molecular weight and solubility. These compounds usually move through the soils with little attenuation and have a moderate to low persistence.

SURFACE WATER

Much of the study area lies within the flood plain of the Souhegan River and is designated within Zone A, the area of 100-year flood, on the National Flood Insurance Program Flood Insurance Rate Map (1). The three principal surface water features that traverse the site are: 1) the Souhegan River, 2) the Hitchiner-Hendrix discharge stream, and 3) Tucker Brook and related wetland areas.

The Souhegan River flows from west to east through the northern portion of the site study area. In the western portion of the site, the flow gradient along the Souhegan River and the hydraulic gradient of the aquifer are relatively steep and the river appears to lose water to the groundwater system on the south side of the river. Through the central portion of the site, as the flow gradient decreases, there is a transition zone where no clear hydraulic gradient exists between the river and the groundwater, and finally, in the eastern portion of the site, the river appears to gain water from the groundwater system. Some heavy metals have been detected in the Souhegan River with levels being higher downstream of the mouth of the Hitchiner- Hendrix discharge stream than upstream.

The Hitchiner-Hendrix discharge stream receives process water discharges from outfall pipes at the Hitchiner, and previously at the Hendrix, facility and flows southwest to northeast across the central portion of the site and into the Souhegan River. There is a discharge pond area on the northern edge of the Hitchiner property where the NPDES permitted discharge from the Hitchiner facility originates. It appears that the central portion of the discharge stream both receives flow from, and discharges to, the groundwater, dependent on fluctuations in groundwater and surface water levels. The downstream portion of the stream consistently discharges to the groundwater and the uppermost portion of the stream also appears to discharge to groundwater. In general, the discharge stream as a whole can be characterized as discharging to the groundwater. Elevated levels of the VOCs 1,1,1-trichloro-ethane and tetrachloroethylene, ABNs, and heavy metals have been detected in the discharge stream, stream sediments, and discharge pond. The discharge stream flows through a portion of the site that is farmland used to grow feed corn.

Tucker Brook flows from the southwest corner of the site, through the southern portion of the site where it is associated with several wetland areas, and eventually discharges into the Souhegan River at the eastern end of the site. There is limited hydrogeologic information available on Tucker Brook and the surrounding wetland areas. No detectable levels of VOCs were found in these areas and only trace amounts of heavy metals and of a single ABN compound, di-n-butylphthalate, were present in Tucker Brook.

SOIL AND SEDIMENT

The stratified deposits that make up the soils in and around the site generally overlay two distinct types of glacial till. The lower till is a compact, poorly sorted mixture of clay, silt, sand, gravel, and boulders. The upper till is a noncompact mixture similar to the lower till with a greater percentage of sand and lesser amounts of silt and clay. Analysis of soil and soil gas samples taken from thirteen areas throughout the site indicated the presence of VOCs in ten of these areas, with the highest concentrations detected in the area between the OK Tool property and the Souhegan River. Soil samples were taken from surface soils and soils down to approximately ten feet in depth. The VOCs detected included 1,1-dichloroethylene, 1,2-dichloro-ethylene, 1,1,1-trichloroethane, tetrachloroethylene, and trichloroethylene. Elevated levels of PCBs were detected in surface and subsurface soils in the vicinity of the OK Tool property and in a soil sample collected adjacent to the Hitchiner-Hendrix discharge stream. Relatively high levels of metals including arsenic, chromium (total), and lead were present in site area soils. Unlike the VOCs, metals and PCBs do not tend to migrate readily through soil or groundwater except under certain environmental conditions. Contaminated soils could potentially be transported off-site via fugitive dusts or by surface runoff (stormwater).

Sediment samples were taken from the Hitchiner-Hendrix discharge stream and the Souhegan River. Low levels of VOCs were detected in sediment samples. PCBs were detected only in discharge stream sediments immediately adjacent to the Hitchiner outfalls, at concentrations up to 6.5 parts per million (ppm). Elevated levels of PAHs were present in sediment samples taken both on- and off-site. Relatively high levels of arsenic, chromium (total), and lead were present in discharge stream sediments immediately adjacent to the Hitchiner outfalls.

AIR

Ambient air monitoring for VOCs was conducted at a location upwind of the site and in three areas located on- and off-site. Low levels of acetone and 1,1,1-trichloroethane were detected at levels slightly above background along the Hitchiner-Hendrix discharge stream. Dichloromethane was detected at one on-site sampling station near the Hendrix facility in 1988 at concentrations exceeding the current NH Ambient Air Guideline (AAG) of 2.0 ug/m3. However, the results from this air sampling episode were suspect as the instruments used during sampling had malfunctioned (1) (13). Tetrachloroethylene was also detected at a sampling station along the Hitchiner-Hendrix discharge stream at levels in excess of the current NH AAG of 0.02 ug/m3 during this sampling round. The release of VOCs from the site to ambient air does not seem to be a major environmental contaminant pathway. Transport of fugitive dusts off-site could be another possible pathway, but has not been monitored to date.

BIOTA

To date, no biological sampling data is available for aquatic biota or agricultural crops in the immediate vicinity of the site. This data would be useful in determining if bioaccumulation of contaminants from the site is occurring in the food chain. Both arsenic and cadmium bioaccumulate in plants and animals (16) (17). Chromium and PCBs can bioaccumulate in fish (18) (19). Nickel tends to bioaccumulate in some aquatic biota (18).

B. HUMAN EXPOSURE PATHWAYS

The exposure pathways of concern at the Savage Municipal Water Supply Site include ingestion, inhalation, and direct contact with contaminants. Groundwater, on-site soils, surface water, and sediments are potential sources for human exposure.

GROUNDWATER

The groundwater in the Savage Municipal Well, the well serving the Milford Mobile Home Park, the Keyes Well, and area private residential wells were found to be unfit for human consumption in 1983 by the NH WSPCC and were subsequently shutdown. The Town of Milford and the mobile home park now derive their water supplies from alternative sources. The only well in the area still in use as a drinking water source is the dug well used by the Milford Drive-In Theater, which is used seasonally and only on a limited basis. At present, human exposure to contaminated water supplies is not of concern. However, past exposure to contaminated groundwater from municipal and private water supply wells is of concern, as the consumers of these water supplies may have been exposed to a variety of carcinogenic (tetrachloroethylene) and noncarcinogenic (1,2-dichloro- ethylene and 1,1,1-trichloro-ethane) VOCs for a number of years. The contaminants present in area groundwater could also migrate through soils and into surface waters, with dermal exposure to contaminants being another potential human exposure pathway. Workers at the three industries still in operation on-site could be potentially exposed to contaminants in groundwater, via inhalation, through industrial process waters where VOCs may volatilize into ambient air.

SURFACE WATER

The detection of VOCs in surface water within the site study area was mainly limited to samples collected from the Hitchiner- Hendrix discharge stream. The VOCs of concern present in area surface waters were: benzene, 1,2-dichloroethylene, 1,1,1-tri-chloroethane, and tetrachloroethylene. Contaminated surface waters have discharged into other surface water bodies, groundwater, and into area soils. Skin contact to contaminated surface water is considered the primary route of human exposure for this pathway. Incidental ingestion of contaminated surface water is another potential exposure pathway of concern. These exposures could occur by accidental exposure to the discharge stream surface waters.

SOIL AND SEDIMENT

The majority of contaminated soils have been found on-site near the properties of the four industries comprising the site. Exposure to elevated levels of VOCs, PAHs, PCBs, and metals present in soils by direct contact is the main pathway of concern for this media. Other potential human exposure pathways are incidental ingestion of contaminated soils and inhalation of contaminated fugitive dusts in the vicinity of the site.

Contaminated sediments have mainly been found in discharge stream sediment samples. Low concentrations of VOCs have been detected, but elevated levels of PAHs, PCBs, and metals were found in surface water sediments. The only potential exposure pathways for sediments are via dermal contact by people wading in area surface waters and via uptake of sediments by aquatic biota. Exposure to contaminated sediments does not seem to be a major exposure pathway of concern.

AIR

Ambient air monitoring in 1988 detected levels of VOCs that were slightly above background levels along the Hitchiner-Hendrix discharge stream. This included the presence of tetrachloro-ethylene at concentrations in excess of the current NH AAG of 0.02 ug/m3. Dichloromethane was detected on-site near the Hendrix facility at concentrations exceeding the current NH AAG of 2.0 ug/m3 in 1988. However, the results of this air sampling episode were suspect as the instruments used during sampling had malfunctioned (1) (15). The release of VOCs from the site to the ambient air does not seem to be a major human exposure pathway. Inhalation of fugitive dusts from the site is a potential exposure pathway of concern if on-site subsurface soils were to be disturbed. No particulate air sampling has been conducted on- or off-site to date.

BIOTA

The Souhegan River is used for recreational fishing. Consumption of fish from the river could be a potential source of contaminant exposure as a result of bioaccumulation of contaminants, such as heavy metals.

However, since metals do not tend to migrate readily through soil or groundwater, this would not be a pathway of major concern.

PUBLIC HEALTH IMPLICATIONS

A. TOXICOLOGICAL EVALUATION

Populations potentially affected by contaminants from the Savage Municipal Water Supply Site are off-site residents, trespassers on-site, and both on- and off-site workers. As discussed in the Environmental Contamination and Other Hazards and Pathways Analyses Sections, residents near the site which had contaminated water supplies may have been exposed to 1,2-dichloroethylene, 1,1,1-trichloroethane, tetrachloroethylene, and trichloroethylene via ingestion of drinking water, dermal contact with water, or inhalation of these compounds from water in the form of vapors. Since these contaminated water supplies are no longer in use, they do not presently pose a risk by ingestion to off-site residents, however, past exposure to carcinogenic and noncarcinogenic VOCs in these contaminated water supplies is still of concern, as these residents may have been exposed to these compounds for a number of years before contaminants were discovered in their water supplies. Area residents may also be exposed to contaminated soils by direct contact and by inhalation of fugitive dusts from the site. Potential exposure by off-site residents to contaminated surface waters by direct contact and incidental ingestion of these waters is also of concern. Children playing on-site would be a population at increased risk of exposure by these routes. Trespassers on-site could also potentially be exposed to contaminated soil and surface water on-site. Workers at the facilities of the three industries still operating on-site are potentially exposed to contaminant areas on-site. Workers who would be involved in any remedial activities at the site would also be potentially exposed to contaminants by oral, dermal, or inhalation routes of exposure. A population of workers potentially exposed to on-site soils would be the construction workers who would be working on the vacant State-owned land next to the OK Tool property, on which the NH DOT is constructing a bridge.

The Savage Municipal Water Supply Site consists of numerous on-site contaminant sources (see Site Description and History Section) and is contaminated with a variety of VOCs, heavy metals, PCBs, and PAHs. Multiple human exposure pathways, both on- and off-site, have been identified. The public health implications for each of these human exposure pathways are detailed below:

  1. Potential past oral, dermal, and inhalation exposure to contaminants in water supply wells as a result of contaminant plume migration.

    As indicated in Appendices III, IV, and V, groundwater both on- and off-site is contaminated with a variety of VOCs and heavy metals. As further indicated, contaminants had been detected in both municipal wells and private residential wells in February 1983, however, all affected residences have since been placed on alternate drinking water sources or other municipal water supplies. The length of previous exposure to contaminated groundwater is not possible to determine, since it is not known exactly when contamination of groundwater may have begun. The health effects resulting from this potential past exposure would be associated primarily with oral exposure (drinking water) and inhalation of vapors from contaminated water. These effects are detailed below. It is important to note that the effects listed below are normally associated with a much higher dose than would be expected to have occurred at the site.

    VOC Contaminants

    Benzene, dichloromethane, tetrachloroethylene, and vinyl chloride are all carcinogens by the oral exposure route; being classified as either human carcinogens or probable human carcinogens by the EPA. These chemicals, including trichloroethylene, also produce a variety of noncarcinogenic toxic effects (primarily neurological and hepatic effects) by oral and inhalation exposure (15). The maximum concentrations detected in groundwater for these chemicals are indicated in Appendices III, IV, and V. These compounds have been found at levels which exceeded EPA's Maximum Contaminant Level (MCL) or Proposed Maximum Contaminant Level (PMCL): benzene (MCL 5 ppb) tetrachloroethylene (PMCL 5 ppb), trichloroethylene (MCL 5 ppb), and vinyl chloride (MCL 2 ppb). The noncarcinogenic VOCs 1,1-dichloroethylene (MCL 7 ppb), 1,2-dichloroethylene (PMCL 100 ppb), and 1,1,1-trichlo-roethane (MCL 200 ppb) have been detected at levels in excess of their MCL or PMCL as indicated in Appendices III, IV, and V. These VOCs may produce neurological and hepatic toxic effects.

    Heavy Metal Contaminants

    As indicated in Appendix IV, the metals arsenic (MCL 0.05 ppm), chromium (MCL 0.05 ppm), and lead (MCL 0.05 ppm) were detected in off-site groundwater at levels above their MCL. Arsenic is classified as a human carcinogen by the EPA. There is evidence that chronic oral exposure to elevated levels of arsenic increase the risk of skin cancer, while inhalation of arsenic is associated with lung cancer. Symptoms of arsenic intoxication include fatigue, anemia, and nerve damage. Inorganic arsenic exists in various chemical and physical states and the effect that this toxic metal has on biological systems is dependent on the available chemical species (16). Chromium is an element that, like arsenic can exist in several different forms. The most common forms are the trivalent, Cr (III), and the hexavalent, Cr (VI) form. Trivalent chromium is the most stable and the most common. Hexavalent chromium occurs rarely in nature because it is easily changed to trivalent chromium in the presence of organic matter. Hexavalent chromium has been implicated in human lung cancer and is classified by the EPA as a human carcinogen, via the inhalation route only (17). The major biological systems affected by lead exposure are the blood, the nervous system, and the kidneys. Symptoms of chronic lead poisoning include malaise, loss of appetite, anemia, and reproductive and kidney dysfunction. Lead is classified as a probable human carcinogen by the EPA (23).

    Manganese, nickel, and vanadium were also present in groundwater at elevated levels. Manganese exists in various forms with the divalent, Mn (II), and the tetravalent, Mn (IV) forms being the most common. Chronic exposure to manganese affects the central nervous system and symptoms from exposure include apathy, anorexia, insomnia, and headache (15). Nickel occurs in many chemical states, but the most prevalent form in the environment is the divalent, Ni (II) form. Nickel is relatively non-toxic when ingested orally. Dermal exposure is one of the most common causes of acute contact dermatitis. Inhalation of Ni (II) over long periods of time has been associated with an asthmatic condition and rhinitis. Nickel is classified as a human carcinogen by EPA, via the inhalation route only (20). Vanadium generally occurs in nature in the trivalent state, V (III). Exposure to vanadium affects the respiratory system and may cause skin and eye irritation. Symptoms of acute exposure include wheezing and chest pain. Chronic respiratory symptoms may include coughing and bronchitis (15).

  2. Dermal, oral (incidental ingestion), and inhalation (vapors and fugitive dusts) exposure to contaminants in surface soils by persons engaged in on-site activities (workers, cleanup personnel, trespassers) and off-site activities (area residents).

    Persons engaged in both on-site and off-site activities have a potential for exposure by multiple routes to a variety of VOCs, heavy metals, and PCBs in surface and subsurface soils. The public health implications of these various exposures are detailed below.

    VOC Contaminants

    1,2-Dichloroethylene, 1,1,1-trichloroethane, tetrachlo-roethylene, and trichloroethylene were among the VOCs found in on-site soil samples. These chemicals volatilize readily and there is a potential health concern for exposure from VOCs vaporizing from these soils to the ambient air. Although elevated levels of VOCs were detected in on-site soils, ambient air monitoring for VOCs in 1988 did not detect elevated levels of VOCs in these samples. The release of VOCs from the site to ambient air does not seem to be a major public health concern. Personnel engaged in cleanup (remediation) activities would most probably be exposed to higher levels of these contaminants, but the use of proper safety procedures and protective equipment should lower the risk of any significant health effects.

    Heavy Metal Contaminants

    The metals arsenic, chromium (total), lead, manganese, nickel, and vanadium were found in on-site and off-site soil samples at concentrations above expected background levels. The health effects resulting from exposure to these metals have been discussed previously (see #1 above). Cadmium was also detected in soil samples at elevated concentrations. Cadmium exists mainly in the divalent, Cd (II) form. Affected organs for chronic exposure include the kidneys, liver, lung, and heart. Cadmium tends to accumulate in the kidneys and liver, being retained in the body for long periods of time. Chronic inhalation exposure may produce pulmonary emphysema and anemia may also result from prolonged exposure. Cadmium is classified as a probable human carcinogen by the EPA, via the inhalation route only (17). Populations potentially exposed to these contaminants in soil include children playing in the vicinity of the site and workers near the former OK Tool facility, where high levels of metals have been found in soil.

    PCB Contaminants

    The PCBs Aroclor 1254 and Aroclor 1260 have been detected in surface and subsurface soil samples both on- and off-site and in on-site sediment samples at elevated levels. These PCBs were found on the grounds of the former OK Tool facility and at one location along the Hitchiner-Hendrix discharge stream. The same populations as mentioned in the heavy metal contaminants section above could be potentially exposed via the oral and dermal routes. PCBs are diverse in both structure and toxic effect. Some toxic effects from exposure in humans are eye irritation, skin problems, and gastro-intestinal dysfunction (19). PCBs are classified as probable human carcinogens by the EPA with long-term exposure to contaminated soils and sediments posing a potential threat to public health.

  3. Oral (incidental ingestion), inhalation, and dermal exposure of persons engaged in recreational activities in the Souhegan River and other area waterways to contaminated surface water and sediment.

    Relatively low levels of the VOCs dichloromethane, tetrachloroethylene, and 1,1,1-trichloroethane were detected in surface water on- and off-site. Very low levels of VOCs were found in sediment samples taken in area waterways. Health effects from exposure to VOCs in these media would appear to be minimal. Heavy metals found in on- and off-site surface water samples were at relatively low concentrations. Elevated levels of heavy metals were detected in sediment samples on- and off-site. The health effects from exposure to these metals have been discussed previously (see #1 above). As prolonged exposure to sediments is not likely to occur, this is not a major human exposure pathway of concern. PCBs were detected at elevated levels in on-site sediment samples only. These PCBs were found in densely vegetated areas with shallow, intermittent flow near the sources of the Hitchiner-Hendrix discharge stream (15). Access to this area is limited and potential for exposure is expected to be minimal. Elevated levels of PAHs were detected in sediment samples on- and off-site. The class of compounds known as PAHs contain many structurally similar compounds which have been shown to be carcinogenic by all routes of exposure. Exposure to PAHs can result in irritation of the skin and respiratory tract (15). The potential exists for a number of adverse health effects to occur from exposure to PAHs in sediment, particularly if prolonged contact should occur.

B. HEALTH OUTCOME DATA EVALUATION

The latest available data from the NH DPHS from 1988 (21) indicated that there is no known increase in the incidence rate for all cancers combined for the Town of Milford, NH at this point in time (22). This is based on data which has been age-adjusted to the 1970 U.S. population.



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