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1. ATSDR > Public Health Assessments & Consultations

PUBLIC HEALTH ASSESSMENT
LINEMASTER SWITCH CORPORATION
WOODSTOCK, WINDHAM COUNTY, CONNECTICUT

ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

The majority of the sampling that was performed at the Linemaster Switch site was included in the 1987 report from the NUS Corporation Field Investigation Team (1), and the 1992 Fuss and O'Neill Inc., Draft Remedial Investigation and Feasibility Study (4,7). During site investigations, ground water, private wells, soil, surface water, and air sampling were conducted.

The following discussion and data tables present the contaminants of concern. Contaminants are presented by the media (soil, ground water, air, and etc.) in which they were found. The contamination is also divided into on-site and off-site. On-site refers to sampling points within the boundaries of the Linemaster Switch property and off-site refers to sampling points not within these boundaries.

These contaminants will be evaluated in subsequent sections of this public health assessment to determine whether exposures to them has public health significance. These contaminants were selected based upon the following factors:

1. Concentrations of contaminants on-site and off-site.



2. Field data quality, laboratory data quality, and sample design.



3. Comparison of on-site and off-site concentrations with health assessment comparison values for non-carcinogenic and carcinogenic end points.



4. Community health concerns.

The listing of a contaminant does not mean that it will cause adverse health effects from exposure. The list indicates which contaminants will be discussed further in the public health assessment.

Comparison values for health assessments are contaminant concentrations in specific media that are used to select contaminants for further evaluation. These values include Environmental Media Evaluation Guides (EMEGs), Cancer Risk Evaluation Guides (CREGs), and other relevant guidelines. EMEGs are calculated from Minimal Risk Levels (MRLs). An MRL is an estimate of daily human exposure to a chemical that is likely to be without appreciable risk of an adverse, non-carcinogenic risk. CREGs are estimated contaminant concentrations based on one excess cancer in a million people similarly exposed over a lifetime. Reference Dose Media Evaluation Guides (RMEGs) are used when EMEGs or CREGs are not available for a specific medium. RMEGs are calculated from the EPA Reference Dose (RfD) which are estimates of the daily exposure to a contaminant that is unlikely to cause adverse health effects. A concentration is calculated from RfDs making certain assumptions about human intake of water or ambient air. Maximum Contaminant Levels (MCLs) represent concentrations that the EPA deems protective of public health (considering the availability and economics of water treatment technology) over a 70 year period of exposure drinking two liters of water per day. A Lifetime Health Advisory (LTHA) is a concentration the EPA has determined to be protective of public health over a lifetime at an exposure rate of two liters of water per day.

A. ON-SITE CONTAMINATION

Preliminary investigations at the site located four potential contaminant source areas; Zone 1, the area of the former dry well and former paint settling booth; Zone 2, the former facility wastewater disposal system; Zone 3, the residential leaching field of the former site owner, and Zone 4, the paint shed area (4). The Zone 1 area east of the facility building was considered a potential source area because it contains the dry well where waste solvents were disposed of from 1969 to 1979. Zone 2 contains the facility wastewater disposal system which was suspected as a potential source area since water obtained from the facility's contaminated production well was discharged into the system. Zone 3 contains the owner's contaminated private water supply well which discharged into this resident's leaching field. Zone 4 contains the paint shed which was used to store solvents and other manufacturing chemicals, this area also was considered a potential source.

The contamination identified in these 4 areas are discussed in this section by medium.

Ground Water

Ground water occurs in unconsolidated overburden till and in shallow bedrock and deep bedrock formations. Ground water flows radially outward in till and shallow bedrock units from the central topographic high where the facility is located.

Ground water flow in the deep bedrock is partially radial and is controlled by fractures and supply-well pumping. Ground water migrates vertically downward from the unconsolidated overburden to the bedrock in the central area of the site. Ground water also migrates vertically upward from the bedrock to the overburden along the site boundaries.

Ground water monitoring data indicate VOCs are present at the highest concentrations in the Zone 1 area and are migrating primarily to the east-northeast in the overburden and bedrock formations.

Metals have been detected in ground water samples and some may be naturally-occurring in the overburden and bedrock formations.

Ground Water Monitoring Wells

Forty-six monitoring wells were installed in till, shallow bedrock, and deep bedrock in 1987, 1989, 1991, and 1992 by the RI/FS consultants (4,7). Ground water samples were collected from monitoring wells by Fuss and O'Neill, in September and October of 1987 and February of 1988 prior to the RI/FS. Additional ground water sampling rounds were conducted in July of 1990 and December of 1990, June and August of 1991 and January and April of 1992, as part of Phase 1 and 2 of the RI/FS. The round 1 sampling of Phase 3, conducted in June, July, and August of 1991, included sampling from: till, shallow bedrock, and deep bedrock wells.

In June of 1992, the Interim Removal Treatment System (IRTS) was initiated for the purpose of recovering and treating VOC contaminated ground water. After six months of operation of the IRTS, the levels of VOCs decreased in seven deep bedrock monitoring wells on-site. However, when the data (through December of 1992) was evaluated, the levels of VOCs in till and shallow bedrock wells had remained relatively unchanged after six months of operation of the IRTS.

Table 1 lists the contaminants detected during these sampling events above comparison values (4,7).

TABLE 1
GROUND WATER CONTAMINATION IN ON-SITE MONITORING WELLS (4,7)
(PRE-REMEDIAL LEVELS)

CREG - Cancer Risk Evaluation Guide
EMEG - Environmental Media Evaluation Guide
LTHA - Lifetime Health Advisory
ND - none detected
ppb - parts per billion
RMEG - Reference Dose Media Evaluation Guide

Ground Water - Private Non-Potable Wells

There are seven water supply wells located on the Linemaster Switch Property. Three are used for drinking and are discussed in the next section. The four other wells are used for production and landscaping. The wells used for landscaping, production etc., are monitored quarterly (March, June, September, and December). VOCs were detected in four private, non potable water wells on-site. These include: the facility's backup well and leaching field landscaping well, the Bald Hill Restaurant's landscaping well, and a well located in a private home used to supply water to two swimming pools. The Linemaster Switch backup production well had the highest levels of VOCs detected above comparison values. Concentrations of TCE have ranged from 5,100 ppb to 59,000 ppb. In addition, sampling in 1986 detected naturally occurring arsenic and lead concentrations above comparison values in the Linemaster Switch backup well.

After four months of the initiation of the IRTS, the levels of VOCs had decreased in the facility backup well from 2,601 ppb (prior to the initiation) to 464 ppb. The VOC levels in the other deep bedrock private wells on-site (e.g. GW-08db and GW-12db; see Figures 2-1 and 2-2 in Appendix C) did not change. Table 2 lists the contaminants detected in on-site non-potable water wells above comparison values.

TABLE 2
ON-SITE PRIVATE NON-POTABLE WATER WELLS (4,7)

CREG - Cancer Risk Evaluation Guide
EMEG - Environmental Media Evaluation Guide
LTHA - Lifetime Health Advisory
MCLG - Maximum Contaminant Level Goal
ND - none detected
ppb - parts per billion
RMEG - Reference Dose Media Evaluation Guide

Groundwater - Private Potable Wells

There are three drinking water supply wells located on the Linemaster Switch Property. These include two private residential wells and one well located at the Bald Hill Restaurant. TCE concentrations were detected above comparison values in all three of these wells. One residence received their water from GW-12 only until 1992 when the IRTS was initiated. Currently, that residence shares a treated water-supply well with the manufacturing facility (GW-08).

The sampling of 1986 also detected arsenic concentrations above comparison values in one private residential well located on-site. Arsenic occurs naturally in the soils and bedrock in the area.

The drinking water wells are monitored bi-monthly (February, April, June, August, October, and December). As noted earlier, these wells have GAC filters. Table 3 lists the contaminants detected, at levels above comparison values, during these sampling events and prior the installation of GAC filters. The concentration of TCE (10,327) was detected in a supply well (GW-12) that is not currently being used.

TABLE 3
ON-SITE PRIVATE DRINKING WATER WELLS (4,7)

CREG - Cancer Risk Evaluation Guide
EMEG - Environmental Media Evaluation Guide
LTHA - Lifetime Health Advisory
MCLG - Maximum Contaminant Level Goal
ND - none detected
ppb - Parts Per Billion
RMEG - Reference Dose Media Evaluation Guide

Subsurface Soil Gas

Soil gas screening surveys were conducted in June of 1987 and December of 1991, at the site. This type of investigation can help identify whether volatile compounds are present beneath the surface. There were four areas of concern which were selected: Zones 1, 2, 3, and 4.

The results of these surveys indicate that VOCs were present in the soil gas in the vicinity of the paint booth, and the former dry well area. TCE was only detected in one gas sample from the private residence's leaching field.

The soil gas screening surveys consisted of field measurements for total VOCs and sampling of vapors for laboratory analysis. Soil gas samples were collected by driving a hollow probe 2 to 3 feet into the subsurface. The field measurements and laboratory samples were taken in soil borings at depths of 0 to 30 feet.

At depths of 0 to 30 feet, VOC gases were detected in Zones 1, 2, 3, and 4. At depths of 0 to 5 feet, Zone 1 had the highest field gas readings ranging from 0 to 71,000 ppb. The highest of these gas readings were found along the east side of the manufacturing building, in the dry well area, and areas directly east of the dry well area. VOC readings detected at depths of 5 to 15 feet ranged from none detected to 210,000 ppb, with the highest gas measurements in the dry well area. At depths of 15 to 30 feet, the highest field gas measurements were 51,590 ppb.

The most common VOC gas detected by laboratory analyses was TCE. It was detected in 67 of 106 samples collected, and all four Zones. Toluene and xylene were found in Zones 1, 2, and 4. Soil gas samples collected beneath the manufacturing building had TCE concentrations ranging from none detected (at 9 to 10 feet) to 5,400 ppb (at 19 to 20 feet). Tetrachloroethylene (PCE) was the second most common VOC detected and was present in a total of five samples collected from Zone 1. In general the highest concentrations were detected in the dry well area. It appears that VOCs have moved under the building toward the northwest, possibly due to ground water transport (4,7). No VOCs were detected on the west side of the manufacturing building, or west of Zone 1.

TABLE 4
LABORATORY SOIL GAS RESULTS(4,7)

ND - None detected
ppb - Parts per billion

Subsurface Soil

Approximately 100 soil samples were collected by Fuss & O'Neill between 1987 and 1992 and analyzed for VOCs, semivolatile organic compounds (SVOCs), and metals (4,7). The samples were taken at depths ranging from 0 to 47 feet. VOCs were detected in soils taken from Zones 1, 2, and 4. The highest concentrations of VOCs were found in soils at Zone 1 indicating this zone as the primary source area for contamination at the site. TCE was detected in 13 out of 41 samples at a minimum depth of 1 to 2 feet and a maximum depth of 15 to 16 feet. Other VOCs detected are PCE, toluene, and xylene at depths of 3 to 15 feet.

There were no VOCs detected in soil samples collected in Zone 3.

In general, the highest VOC concentrations were detected in samples collected from below the water table in the area adjacent to the former dry well location (Zone 1). The lowest VOC concentrations were detected in the soil samples taken on the western side of the manufacturing facility. The soil investigation indicates that the contaminants are migrating underneath the building in Zone 1.

Arsenic and cadmium were detected in Zone 1, (in the vicinity of the former dry well) and in Zone 2, (at the brick dry well area). Table 5 lists the contaminants detected during these sampling events above comparison values.

TABLE 5
SOIL CONTAMINATION (4,7)

CREG - Cancer Risk Evaluation Guide
ND - None detected
ppm - parts per million
EMEG-C - Environmental Media Evaluation Guide for Children
RMEG-C - Reference Dose Media Evaluation Guide for Children

Sewage Sludge

Sludge samples were collected from the sewage settling tank, and from a trench in the vicinity of the sewage holding tanks in Zone 2, and the area in the vicinity of the brick dry well. The brick dry well was sampled because this area received most of the facility sewage. Low levels of VOCs were found in the sludge samples collected from the trench area. TCE was the primary compound found. It is believed that this contamination resulted from ground-water transport.

Surface Water

In December of 1985, February of 1986, and March of 1987, NUS collected 9 surface water samples from 6 locations on-site. These sampling locations were at a wetland area at the northwest corner of the site, Pond 1, Pond 2, Pond 3, and from an unnamed stream located along the southeastern property boundary which crosses Route 171. In July of 1990, Fuss & O'Neill collected 8 surface water samples from these same water bodies. Surface water samples were collected from Pond 3 in December of 1990, March of 1991, April of 1991, June of 1991, and May of 1992 (7).

Arsenic and TCE were detected in Pond 1 at 1.8 ppb and 6.7 ppb respectively. There was no TCE detected in Pond 2, but Arsenic was detected at 1.6 ppb, and chloroform was detected at an estimated value of 2 ppb. Arsenic and TCE were detected in Pond 3 at 3.7 ppb and 10 ppb respectively.

Sediment

In December of 1985, and February of 1986, NUS/FIT collected sediment samples. The samples were obtained from the wetland area at the northwest corner of the site, Pond 1, Pond 2, Pond 3, and from an unnamed stream located along the southeastern property boundary. This stream crosses Route 171. No contaminants were detected above health comparison values (1).

Indoor Air

According to the NUS/FIT 1987 report, the Occupational Safety and Health Administration (OSHA) performed air monitoring inside the factory building near the painting booths and the TCE vapor degreaser. No contaminants were detected in the breathing zone.

Ambient Air

No ambient air sampling was performed during the RI/FS. However, as part of the RI/FS, Fuss and O'Neill performed Air Dispersion Modeling starting with the meteorologic year of 1972 to present. The model is an estimate of potential contaminant concentrations from exposure points. The point sources modeled in this study fall into three categories: a point source consisting of an ongoing manufacturing process producing air emission, a point source from the exhaust of the existing air stripping column that treats contaminated ground water, and the emissions from a contaminated soil source located in Zone 1. The model was used to predict potential ground-level concentrations of TCE on an annual basis. The maximum ground-level concentrations predicted for TCE along the property boundary are above health comparison values.

However, the results of the modeling are not based on actual ambient air sampling data but extrapolations and interpretations of data from other media (soil and ground water). Thus, the reader should recognize that models contain assumptions that influence the validity of the predictions derived from this model. The ATSDR policy states that modeling cannot serve as proxy for actual measurement of existing conditions when determining public health implications. Table 6 lists the range of contaminant concentrations derived from the ambient air model.

Table 6
Range of Contaminant Concentration of Modeled Ambient Air(4,7)

ug/m³ - microgram per cubic meter
CREG - Cancer Risk Evaluation Guide

B. OFF-SITE CONTAMINATION

Ground Water - Private Wells

There are 51 private residential drinking water wells located along the periphery of the site that supply water to approximately 130 people (see Figures 2-1 and 2-2 in Appendix C).

In December of 1985, and February and June of 1986, NUS sampled a total of 13 off-site residential wells to assess what wells may have been impacted by contaminants migrating off-site. These wells are located northeast on Route 169 and southeast on Route 171. The initial two rounds of sampling detected TCE above comparison values in three private residential wells, and at the Woodstock Town Hall drinking water well.

As part of the RI/FS (4,7) 26 off-site residential wells have been tested by Fuss and O'Neill. A total of fourteen wells located north and south of the site have been found to contain TCE.

There is another source of private drinking water well contamination in the area not related to the Linemaster Switch site. Eight wells located along Frog Pond Road and Wainwright Drive have been contaminated with benzene and MTBE above comparison values from a leaking underground fuel storage tank located at the Woodstock Public School. In 1993, TCE was detected in three of the eight wells. The wells are located approximately 400 feet northeast of the Linemaster Switch property boundary. All the wells that have been identified as contaminated were initially provided with bottled water and subsequently with granulated activated carbon filters.

During sampling conducted in July of 1990, concentrations of arsenic were detected above health comparison values in private drinking water wells GW-21 and GW-34db. In January of 1993, a third private well GW-69db (see Figures 2-1 and 2-2 in Appendix C), had arsenic detected at levels above health comparison values. Because this well is not contaminated with site-related compounds, a filter system has not been provided for them. Although the residents treat their water with a water softener to lower the arsenic levels, the arsenic levels after treatment are still above comparison values. As noted above, these arsenic levels are not related to Linemaster Switch, but are naturally occurring.

Table 7 lists those contaminants detected in off-site private wells above comparison values (prior to treatment).

TABLE 7
OFF-SITE GROUND WATER CONTAMINATION IN PRIVATE WELLS(4,7,25)

CREG - Cancer Risk Evaluation Guide
LTHA - Lifetime Health Advisory
MCLG - Maximum Contaminant Level Goal
ND - none detected
ppb - parts per billion

After six months of the initiation of the IRTS, the TCE levels at GW-06db, GW-09db, GW-53, GW-55 and GW-57 were reduced to below 5 ppb.

C. QUALITY ASSURANCE AND QUALITY CONTROL

There are two consulting firms that have conducted analyses of soil, ground water, surface water, and sewage leachate (1,4,7). The Quality Assurance-Quality Control (QA-QC) procedures used by these consultants were not evaluated by the CT DPHAS. The QA/AC summary procedures were not obtained from the EPA in the RI/FS data. Therefore, the conclusions drawn for this health assessment are determined by the availability and reliability of the referenced information and it is assumed that adequate quality assurance and quality control measures were followed with regard to chain of custody, laboratory procedures, and data reporting.

D. TOXIC RELEASE INVENTORY

To identify possible facilities that could contribute to contamination near the site, Toxic Release Inventory (TRI) was searched for the years: 1987, 1988, 1989, 1990, and 1991. The TRI contains information on total releases of chemicals from certain industries. There were no releases reported in Woodstock, CT, for the years 1987, 1988, 1989, 1990, or 1991.

E. PHYSICAL AND OTHER HAZARDS

No physical or other hazards were identified during the site visit or data investigation.

PATHWAYS ANALYSES

To determine whether nearby residents have been or are being exposed to contaminants migrating from the site, the CT DPHAS and the ATSDR evaluate the environmental and human exposure and an exposed population. The pathway analysis consists of five elements: a source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and an exposed population. The exposure pathways discussed here are ground water and soil. The ATSDR categorizes exposure pathways as either completed or potential pathways. For an exposure pathway to be completed all five elements of the pathway must be present. Potential pathways are those where there is not sufficient evidence to show that all the elements are present now, could be present in the future, or were present in the past.

A. COMPLETED EXPOSURE PATHWAYS

People on-site and off-site who drank or used water from contaminated wells were exposed to volatile organic compounds and metals. These exposures ceased after bottled water was provided and water filtration units were installed. Table 8 depicts the location, type of property and estimated number of persons exposed to PCE or TCE above the comparison values.

Table 8
ESTIMATED NUMBER OF PERSONS EXPOSED TO DRINKING WATER CONTAMINATED WITH PCE ABOVE 0.7 OR TCE ABOVE 3.0

Ground Water

Contamination Source: Linemaster
Exposure Location: On-site
Exposed Population(s): Workers and residents

People who worked at Linemaster Switch, the Woodstock Town Hall, the Woodstock Fire Station, the Bald Hill Restaurant, and residents living on the Linemaster Switch site were exposed to contaminated water for an unknown period of time between 1969 and 1986. Private well water was contaminated with volatile organic compounds including TCE which was used at the Linemaster Switch facility. Exposures occurred through ingestion and skin contact with contaminated water, as well as through inhalation of chemicals that enter the air during water usage. These exposures stopped in 1986 at which time the water filtration devices were installed.

Ground Water

Contamination Source: Linemaster
Exposure Location: On-site
Exposed Population(s): Residents using on-site swimming pools

People who used one or more of the swimming pools located on the Linemaster Switch site were exposed to contaminated water for an unknown period of time between 1960 and 1986. These pools were supplied with water containing TCE and PCE. However, because of the volatility of the compounds detected in the ground water, the actual presence of VOCs in the on-site swimming pools is questionable.

Ground Water

Contamination Source: Linemaster
Exposure Location: Off-site
Exposed Population(s): Residents

Private drinking water wells from nine residences and two apartment buildings located off-site were contaminated with volatile organic compounds including TCE which was used at the Linemaster Switch facility. These residents were exposed to contaminated water for an unknown period of time between 1969 and 1986. Exposures occurred through ingestion and skin contact with contaminated water, as well as through inhalation of chemicals that enter the air during water usage. These exposures stopped in 1986 at which time the water filtration devices were installed.

Ground Water

Contamination Source: Woodstock School
Exposure Location: Off-site
Exposed Population(s): Residents

Residents who used wells located on Davis Drive, Frog Pond Road, and Wainwright Road found to be contaminated, were exposed to MTBE and benzene contaminated water for an unknown period of time prior to 1992. Exposures occurred through ingestion and skin contact with contaminated water, as well as through inhalation of chemicals that enter the air during water usage. Private well water was contaminated with MTBE and benzene from underground fuel tanks that were removed from the Woodstock School in November of 1988.

Eight wells were contaminated with benzene and MTBE above comparison values. Sampling performed by the CT DEP detected the contamination between January of 1991 and November of 1992. Present and future exposures to benzene, MTBE, and other VOCs are unlikely since GAC treatment devices are installed and monitoring is being conducted. However, if individual filters fail to function properly, then future exposures are possible from water contaminated with benzene and MTBE.

Bottled water was initially provided by the CT DEP in 1992. Granulated activated carbon (GAC) filtration systems were subsequently installed in all eight wells in the vicinity of the Woodstock School in 1992 and 1993.

Ground Water

Contamination Source: Plumbing-based lead
Exposure Location: On-site and Off-site
Exposed Population(s): Residents

People were and may continue to be exposed to lead from drinking water contaminated with lead. Lead was detected in two private wells on-site and five wells off-site. The source of lead is believed to be from the plumbing fixtures⁴ in the individual homes since lead was not detected in monitoring wells. Therefore the potential exists for persons to be exposed to lead through ingestion. While lead can be ingested, inhalation of lead during showering is unlikely.

Ground Water

Contamination Source: Naturally occurring arsenic
Exposure Location: Off-site
Exposed Population(s): Residents

Arsenic occurs naturally in the overburden and bedrock aquifers in the town of Woodstock. Arsenic was identified above comparison values in twenty-five off-site private wells. Therefore, the potential exists for a large portion of the population to be exposed to levels of arsenic above comparison values. These persons would be exposed to arsenic through ingestion and skin contact. While arsenic can be ingested, inhalation of arsenic during showering is unlikely.

B. POTENTIAL EXPOSURE PATHWAYS

Ground Water - Private Well Pathway

Present and future ingestion, inhalation, and dermal exposures to ground water contaminated with VOCs are unlikely to occur for residents with private wells in the area. The levels of TCE have been decreasing in those wells located directly north and south of the site since the ground water recovery system was installed. Moreover, the CT DEP in cooperation with the EPA have setup an extensive groundwater monitoring program designed to monitor on-site and off-site potable and non-potable wells. The monitoring program, in addition to the granulated activated filter installations and the IRTS installation, would reduce the possibility that residents in the area could be exposed to TCE through ingestion, inhalation or dermal contact. Such exposure would occur only if the monitoring and treatment systems in place do not function as designed. The monitoring system has been effective at detecting contaminant migration. For example, TCE was detected in the Spring of 1993 in wells located to the northeast of the site.

Soil Pathway

Inhalation exposures of airborne soil particulates is unlikely since the site is heavily vegetated and landscaping of the soil areas is very well maintained. In addition, Zones 1 and 4 have been capped with a plastic cover. However, future ingestion, inhalation, and dermal exposures to VOCs could occur if the soil were excavated for landscaping, construction or road work purposes on-site and in the surrounding areas where contaminated ground water has been identified (to the south, north, and northeast of the site).

Indoor Air Pathway

Present and future inhalation exposures are possible in on-site and off-site residential basements where VOC contaminated ground waters were detected.

PUBLIC HEALTH IMPLICATIONS

A. TOXICOLOGICAL EVALUATION

Completed and potential exposure pathways have been identified for ground water. In this section, the health effects associated with exposure to contaminants of concern will be discussed.

To evaluate health effects, the ATSDR has developed a Minimal Risk Level (MRL) for contaminants commonly detected at hazardous waste sites. The MRL is an estimate of daily human exposure to a contaminant below which non-cancer, adverse health effects are unlikely to occur. MRLs are developed for each route of exposure such as ingestion, inhalation, and dermal absorption and for the length of exposure, such as acute (less than 15 days), intermediate (15 to 364 days), and chronic (greater than 364 days).

We used the ATSDR Toxicological Profiles in our review of the health effects associated with site contaminants. The ATSDR Toxicological Profiles are chemical-specific profiles which provide information on health effects, environmental transport and human exposures (8, 9, 10, 12, 13, 14; 23, 24; 26, 27, 28, 29, 30, 31, 32, 33).

Trichloroethylene (TCE)

Exposure to TCE occurred in the past to persons who drank water from contaminated private wells for 19 years. The maximum concentration of TCE detected in potable wells located on-site was 10,327 ppb. The maximum concentration of TCE detected in off-site wells was 220 ppb. We will be calculating two different exposure scenarios. One utilizing the maximum TCE detected on-site (10,327 ppb), and one utilizing the maximum TCE detected off-site (220 ppb).

The amount of TCE ingested per body weight was calculated for adults and children. This value is commonly represented as a mass of contaminant per mass of body weight per day. The mass of contaminant is often listed in milligrams (mg). There are one thousand mg in one gram. The mass of body weight is often listed as kilograms (kg). One kg equals one thousand grams. The mass of contaminant per mass of body weight per day is thus written as follows: mg/kg/day. This number is defined as an ingestion exposure. These values are then compared to a minimal risk level (MRL). The MRL represents a level of exposure of a chemical to a person that is likely to be without adverse health effects for a given period of exposure. Many compounds have three MRL values that represent three exposure durations: acute (less than 15 days), intermediate (15 to 364 days), and chronic (greater than 364 days). There is only one MRL for TCE, namely the intermediate value which equals 0.7 mg/kg/day.

Calculations Based On Maximum TCE Detected On-Site
Non-cancerous Effects

The ingestion exposure calculated for adults is 0.295 mg/kg/day and for children is 1.03 mg/kg/day. The ingestion exposure calculated for an adult does not exceed the intermediate MRL, therefore adverse health effects would not be anticipated in adults who drank this water for up to one year. This maximum concentration does, however, exceed the intermediate MRL for children. Since chronic MRLs for other compounds, when available, are always equal to or smaller than the intermediate MRLs, we conclude that non-cancerous adverse effects are possible for children who drank water containing 10,327 ppb TCE from on-site wells for as long as 19 years⁵. We are unable to conclude if non-cancerous adverse effects are possible for adults who drank water containing 10,327 ppb TCE from on-site wells for as long as 19 years.

Calculations Based On Maximum TCE Detected Off-Site
Non-cancerous Effects

Using the highest TCE concentrations detected in the off-site wells (220 ppb) the ingestion exposure calculated for adults is 0.006 mg/kg/day, and for children is 0.02 mg/kg/day. Neither value exceeded the ATSDR intermediate MRL of 0.7 mg/kg/day. Therefore, non-cancerous adverse health effects are unlikely to occur in children or adults who drank TCE from off-site wells for up to one year.

Inhalation and ingestion studies indicate that the bone marrow, CNS, liver, and kidney are principal targets of TCE in animals and humans. CNS effects are related primarily to narcosis. Effects on the liver and kidney include organ enlargement and biochemical changes. Less adequately characterized effects include impaired blood component production. Other blood changes have been observed in rats exposed to TCE by inhalation. The use of TCE as an anesthetic agent has been associated with cardiac arrhythmias. When pregnant rats were exposed to very high concentrations of TCE there is evidence that the offspring born exhibited a reduced birth weight (9).

One investigation conducted in Michigan examined the relationship between human consumption of water contaminated by solvents, (including: benzene, TCE, and PCE among others), and the incidence of low birth weight. This investigation concluded, among other things, that there was an association between consumption of water contaminated with solvents and the incidence of low birth weight (34).

Inhalation studies with rats and mice indicate that TCE is a developmental toxicant. Toxicity to the fetus is observed primarily as skeletal alterations, and other effects consistent with delayed maturation. Oral studies with rats and mice showed no TCE-related effects on fertility or other indicators of reproductive performance. Commercial grade TCE may be weakly mutagenic (ability to alter DNA) in humans.

Carcinogenicity Classification:
TCE was classified as a probable human carcinogen (EPA group B2). Currently, however, this classification has been withdrawn, and a review of this compound is being conducted by the EPA (9). Although the review is not yet complete, we calculated cancer risks for adults and children using available information from the Environmental Criteria and Assessment Office of the U.S. EPA (37). The longest period of time children and adults may have been exposed to TCE is 19 years. Consequently, we utilized this value in our estimates. The cancer risks listed below, were based on worst case scenarios. The actual risks may be lower, perhaps even zero.

Calculations Based On Maximum TCE Detected On-Site
Cancerous Effects

These calculations were based on the maximum concentration of TCE detected on-site, 10,327 ppb. On the basis of our conservative estimates, children and adults who drank and bathed in water containing TCE at the maximum concentration detected in on-site wells of 10,327 ppb for 19 years, may have a moderate increased risk for developing cancer.

Calculations Based On Maximum TCE Detected Off-Site
Cancerous Effects

These calculations were based on the maximum concentration of TCE detected off-site, 220 ppb. On the basis of our conservative estimates, children and adults who drank and bathed in water containing TCE at the maximum concentration detected in off-site wells of 220 ppb for 19 years, have a low increased risk for developing cancer.

There are various occupational investigations that examined workers who have been exposed to TCE. Many investigations have concluded that workers exposed to TCE do not have higher rates of cancer when compared to workers who were not exposed to TCE (9).

There were two investigations examining populations exposed to TCE in their drinking water. One study examined populations exposed to TCE and PCE from two municipal wells in Woburn, Massachusetts. An increase in childhood leukemia was observed in this community (19). A second study of New Jersey communities found an increase in leukemia in females exposed to TCE (19). The scientific community has raised concern over the reliability of this evidence. Consequently, the conclusions drawn from these studies are irresolute (9).

Brief Description of Chemical:
TCE is a non-flammable liquid that has a sweet odor. This man-made compound is not detected naturally in the environment. TCE is used as a metal degreaser, paint thinner, spot remover and in the manufacture of adhesives.

1,1,2,2-Tetrachloroethane

Exposure to 1,1,2,2-tetrachloroethane occurred in the past to persons who drank from contaminated private wells for 19 years. Using the highest 1,1,2,2-tetrachloroethane concentration detected in the wells (2.1 ppb) the ingestion exposures calculated for adults (0.00006 mg/kg/day) and children (0.00021 mg/kg/day) do not exceed the ATSDR chronic MRL (0.3 mg/kg/day). Therefore, non-cancerous adverse health effects are unlikely to occur in those who drank water contaminated with 1,1,2,2-tetrachloroethane for over one year.

Carcinogenicity Classification:
1,1,2,2-Tetrachloroethane has been classified by the EPA as a possible human carcinogen (group C). Chemicals classified as group C carcinogens generally lack sufficient information to calculate cancer risk estimations. Moreover, these compounds are in a category in which the information available is equivocal and generally inadequate.

Brief Description of Chemical:
1,1,2,2-Tetrachloroethane is a colorless, synthetic liquid that has no natural sources. This compound has a penetrating sweet smell, and historically has been used to clean and degrease metals. Additionally, 1,1,2,2-tetrachloroethane has been used in the production of paints and pesticides.

1,1-Dichloroethylene (1,1-DCE)

Exposure to 1,1-dichloroethylene occurred in the past to persons who drank from contaminated private wells for 19 years. Using the highest 1,1-dichloroethylene concentration detected in the wells (29 ppb) the ingestion exposures calculated for adults (0.00083 mg/kg/day) and children (0.0029 mg/kg/day) do not exceed the ATSDR chronic MRL (0.009 mg/kg/day). Therefore, non-cancerous adverse health effects are unlikely to occur in those who drank water contaminated with 1,1-dichloroethylene for over one year.

Carcinogenicity Classification:
1,1- Dichloroethylene has been classified by the EPA as a possible carcinogen (group C). There is insufficient information to calculate cancer risk estimates for individuals potentially exposed via contaminated drinking water.

Brief Description of Chemical:
1,1-Dichloroethylene is a colorless, synthetic liquid that has no natural sources. This compound may be detected in groundwater as a breakdown product of TCE and PCE.

1,2-Dichloroethane

Exposure to 1,2-dichloroethane occurred in the past to persons who drank from contaminated private wells. The duration of exposure was 19 years. Using the highest 1,2-dichloroethane concentration detected in the wells (1.3 ppb) the ingestion exposures calculated for adults (0.000037 mg/kg/day) and children (0.00013 mg/kg/day) do not exceed the ATSDR intermediate MRL (0.2 mg/kg/day). Therefore, non-cancerous adverse health effects are unlikely to occur in those who drank water contaminated with 1,2-dichloroethane for up to one year. For exposures beyond one year, we lack sufficient information to conclude if health effects may occur. The maximum concentration is below the EPA established Maximum Contaminant Level (MCL) for 1,2-dichloroethane of 5 ppb. MCLs represent contaminant concentrations that EPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an ingestion rate of two liters of water per day. Consequently, if the maximum level detected in private wells was detected in a public water supply these levels would be permitted for all drinking, cooking, and bathing needs.

Carcinogenicity Classification:
1,2-Dichloroethane has been classified by the EPA as a probable human carcinogen (group B2). The estimated cancer risks were calculated using the highest 1,2-dichloroethane concentration detected (1.3 ppb). The cancer risk estimates were calculated for children and adults for a nineteen year period indicate that there is an insignificant risk for developing cancer.

Brief Description of Chemical:
1,2-Dichloroethane is a man-made liquid not detected naturally in the environment. This compound has a mild odor. 1,2-Dichloroethane has been used as a solvent to remove grease from metals parts.

1,2-Dichloroethylene

Exposure to 1,2-dichloroethylene occurred in the past to persons who drank from contaminated private wells for 19 years. This compound exists in two forms, one known as cis-1,2-dichloroethylene, the other as trans-1,2-dichloro-ethylene. Since there are two forms of this compound, the most toxic form (trans-1,2-dichloroethylene) will be used as a worst case assumption for exposure dose calculations.

Using the highest 1,2-dichloroethylene concentration detected in the wells (3558 ppb) the ingestion exposures were calculated for adults (0.10 mg/kg/day) and children (0.36 mg/kg/day). Since there is no chronic MRL, the calculated dose from the maximal concentration of 3558 ppb has been compared to a reference dose. The reference dose (RfD) is an estimated daily intake of a chemical that is likely to be without an appreciable risk of health effects, and has been developed by the EPA. Using the RfD as a comparison the non-carcinogenic health risks for an adult exposed to trans-1,2-dichloroethylene may be characterized as low. The risks for a child are potentially higher.

There is little information in the scientific literature about the effects of oral exposure to 1,2-dichloroethylene in humans. There is evidence that suggests when animals were exposed to very high concentrations of this compound depressed breathing and decreased activity were observed. Additionally, adverse toxic effects included liver damage (increase in liver enzymes), and kidney damage (an increase in kidney weight) (24).

Carcinogenicity Classification:
There is insufficient information regarding human carcinogenicity for both cis,1,2-dichloroethylene and trans-1,2-dichloroethylene.

Brief Description of Chemical:
1,2-Dichloroethylene is a flammable, colorless liquid with a pungent odor. This compound is man made, and has no natural sources. This compound is also a breakdown product of trichloroethylene and tetrachloroethylene.

Arsenic

Arsenic was detected in twenty-seven private residential wells, the Woodstock School well, a well serving an apartment, and two wells serving a restaurant. The levels measured in all the wells ranged from ND to 57.3 ppb. This is not related to the Linemaster site.

Exposures to arsenic may have occurred in the past, and could be occurring presently to persons who drink water from arsenic contaminated private wells. We will be calculating two different exposure scenarios. One utilizing the maximum arsenic detected on-site (288 ppb), and one utilizing the maximum arsenic detected off-site (57.3 ppb).

Calculations Based On Maximum Arsenic Detected On-Site
Non-cancerous Effects

Exposures to arsenic may have occurred in the past, and could be occurring presently to persons who drink water from arsenic contaminated on-site private wells. Using the highest arsenic concentration detected in raw well water (288 ppb) the ingestion exposures calculated for adults (0.0082 mg/kg/day) and children (0.0288 mg/kg/day) do exceed the ATSDR chronic MRL (0.0003 mg/kg/day).

Chronic ingestion investigations in humans indicate that the lowest observable adverse effect level (LOAEL) for skin effects is approximately 0.019 mg/kg/day. Because certain individuals may be more sensitive to arsenic exposures, the possibility exists for skin irritations or darkening of skin color to occur to people who consume drinking water contaminated with arsenic at the maximally detected concentration of 288 ppb. Additionally, people exposed to arsenic at levels of 288 ppb for extended periods of time may experience abdominal pain or irritation.

These non-cancerous health effects were based on the highest arsenic concentration. The actual concentration of arsenic people may have been exposed to from drinking contaminated water may have been lower or perhaps even zero. We assume that adults drink 2 liters (66 ounces) of tap water each day for one year and weigh 70 kg (154 pounds) and children drink one liter (33 ounces) of tap water each day for a year and weigh 10 kg (22 pounds).

Calculations Based On Maximum Arsenic Detected Off-Site
Non-cancerous Effects

Exposures to arsenic may have occurred in the past, and could be occurring presently to persons who drink water from arsenic contaminated off-site private wells. Using the highest arsenic concentration detected off-site in well water (57.3 ppb) the ingestion exposures were calculated for adults (0.00164 mg/kg/day) and children (0.00573 mg/kg/day) and are above the chronic MRL of 0.0003 mg/kg/day. However, this level did not exceed the LOAEL for skin effects (0.019 mg/kg/day). Consequently, non-cancerous adverse health effects are not likely to occur in persons who drink arsenic contaminated water for more than one year.

Carcinogenicity Classification:
Arsenic has been classified by the EPA as a known human carcinogen (EPA group A). When people are exposed to high levels of arsenic through drinking water over extended durations (many years), there is an increased risk for developing skin cancer.

Calculations Based On Maximum Arsenic Detected On-Site
Cancerous Effects

Because arsenic is a known human carcinogen (EPA group A), the estimated cancer risks were calculated using the highest arsenic concentration detected on-site (288 ppb). The cancer risk estimates calculated for children and adults for a nineteen year period indicate that there is a high increase risk for developing skin cancer.

Calculations Based On Maximum Arsenic Detected Off-Site
Cancerous Effects

The cancer risk estimates using the highest arsenic concentration detected off-site (57.3 ppb) for children and adults for a nineteen year period indicate that there is a moderate increased risk for developing skin cancer.

Brief Description of Chemical:
Inorganic arsenic is a naturally-occurring element found in higher concentrations in the overburden and bedrock in the Woodstock area. This is apparently the source of contamination of local wells.

Benzene

Benzene was detected at the well serving the Woodstock Public School (2.6 ppb) and in eight private residences at levels ranging between none detected to 250 ppb. This is not related to the Linemaster Switch site. The duration of potential exposure is likely to have been four years from 1988 through 1991.

Carcinogenicity Classification:
Benzene has been classified by the EPA as a known human carcinogen (EPA group A). When people are exposed to high levels of benzene over extended durations (many years), there is an increased risk for developing leukemia.

The cancer risks were calculated for residents who drank from wells contaminated by the Woodstock School underground storage tank. We used the maximum benzene concentration (250 ppb), and conclude that there is a low increased risk for developing leukemia (10).

Brief Description of Chemical:
Benzene is a colorless liquid with a sweet odor. This compound dissolves in water easily and evaporates readily into the air. Benzene is a highly flammable liquid and is a component of gasoline.

Bromodichloromethane (BDCM)

Exposure to BDCM occurred in the past to persons who drank from contaminated private wells. The duration of exposure was 19 years. Using the highest BDCM concentration detected in the wells (5.1 ppb) the ingestion exposures calculated for adults (0.00015 mg/kg/day) and children (0.00051 mg/kg/day) do not exceed the ATSDR chronic MRL (0.02 mg/kg/day). Therefore, non-cancerous adverse health effects are unlikely to occur in those who drank water contaminated with BDCM for over one year.

Carcinogenicity Classification:
BDCM has been classified by the EPA as a probable human carcinogen (EPA group B2). The cancer risk estimates calculated for children and adults for a nineteen year period indicate that there is no apparent risk for developing cancer.

Brief Description of Chemical:
BDCM is a man-made compound used as a solvent and was used as a flame retardant. This compound is an intermediate for other chemical processes. BDCM is also formed as a by product of water chlorination.

Bromoform

Exposure to bromoform occurred in the past to persons who drank from contaminated private wells for 19 years. Using the highest bromoform concentrations detected in the wells (889 ppb) the ingestion exposures calculated for adults (0.0254 mg/kg/day) and children (0.0889 mg/kg/day) do not exceed the ATSDR chronic MRL (0.2 mg/kg/day). Therefore, non-cancerous adverse health effects are unlikely to occur in those who drank water contaminated with bromoform for over one year.

Carcinogenicity Classification:
Bromoform has been classified by the EPA as a probable human carcinogen (EPA group B2). Epidemiologic studies suggest an association between cancer (12) of the large intestine, rectum, and/or bladder in humans and the constituents of chlorinated drinking water. Bromoform is one of several volatile organic contaminants typically found in chlorinated drinking water that are considered to have carcinogenic potential. The cancer risk estimates calculated for children and adults for a nineteen year period indicate that there is a low increase risk for developing bladder cancer.

Brief Description of Chemical:
Bromoform is a colorless, heavy, nonflammable liquid with a sweetish odor. This compound has been used to dissolve dirt and grease. Bromoform is also a by product of water chlorination.

Cadmium

Exposure to cadmium occurred in the past to persons who drank from contaminated private wells. The duration of exposure was 19 years. Using the highest cadmium concentration detected in the wells (30 ppb) the ingestion exposures calculated for adults (0.00086 mg/kg/day) and children (0.003 mg/kg/day) do exceed the ATSDR chronic MRL (0.0007 mg/kg/day). Although the chronic MRL was exceeded, the health effects described in human studies indicate that the non-carcinogenic health risks for an adult exposed to cadmium are minimal, and the risks for a child may be characterized as low (28).

The main target of cadmium toxicity is the kidney. This specificity has been confirmed in animal studies examining rats, mice, and rabbits. These investigations have lead to a better understanding of cadmium toxicity. The toxic effect appears only to occur after a critical concentration is reached. In other words, low levels of cadmium may not cause damage. However, once the cadmium level has reached the critical value, kidney damage may continue subsequent to exposure cessation. This damage may alter the calcium balance in the body, and increase the risk for osteoporosis among women (28).

Carcinogenicity Classification:
Cadmium has been classified by the EPA as a probable human carcinogen (EPA group B1) by inhalation. However, there is insufficient evidence to ascertain whether cadmium is a carcinogen by ingestion. No cancer risk estimates were calculated for individuals potentially exposed via contaminated drinking water.

Brief Description of Chemical:
The element cadmium occurs naturally in the crust of the earth. The pure form is a soft, white-silver metal. Cadmium is used in many industrial and consumer products including metal coatings.

Chloroform

Elevated levels of chloroform were detected in the well serving the Tarr Apartments at levels ranging from ND to 111 ppb. Consequently, exposure to chloroform occurred in the past to persons who drank from contaminated private wells for 19 years. Using the highest chloroform concentration detected in the wells (111 ppb) the ingestion exposures were calculated for adults (0.003 mg/kg/day) and children (0.01 mg/kg/day). These values were compared to the ATSDR chronic MRL (0.01 mg/kg/day). Non-cancerous adverse health effects are unlikely for adults, and minimal for children who drank water contaminated with chloroform for over one year.

Carcinogenicity Classification:
Chloroform has been classified by the EPA as a probable human carcinogen (EPA group B2). The cancer risk estimates calculated for a nineteen year period indicate that there is no apparent risk for developing cancer.

Brief Description of Chemical:
Chloroform is a colorless liquid that has a pleasant odor, and a slightly sweet taste. Chloroform is used in the production of paper, and is a by product of water chlorination.

Chromium

Exposure to chromium occurred in the past to persons who drank from contaminated private wells for 19 years. The maximum concentration detected in on-site drinking water wells was 625 ppb. This element exists in several different forms, chromium(0), chromium(III), and chromium(VI) (30). The most toxic form is chromium(VI). Using the highest chromium concentration detected in the wells (625 ppb), the ingestion exposure was calculated for adults (0.018 mg/kg/day) and children (0.063 mg/kg/day). These values are usually compared to MRLs. However, there are no acute, intermediate, or chronic MRLs for chromium(VI) to compare with these ingestion exposures. The RfD for chromium(VI) is 0.005 mg/kg/day. This value was exceeded. Consequently, we reviewed human investigations examining the health effects of prolonged exposure to chromium in drinking water. The lowest level of human exposure to chromium in drinking water reported to result in an adverse effect was 0.57 mg/kg/day. Since this value is greater than either the adult or child ingestion exposures, non-cancerous adverse health effects are unlikely for adults or children who drank water contaminated with chromium at the maximum concentration.

Carcinogenicity Classification:
Chromium (VI) has been classified by the EPA as a known human carcinogen (EPA group A) by inhalation. However, there is insufficient evidence to ascertain whether chromium(VI) is a carcinogen by ingestion. No cancer risk estimates were calculated for individuals potentially exposed via contaminated drinking water.

Brief Description of Chemical:
Chromium is a element that occurs naturally in rocks and soil. This element exists in several different forms, chromium(0), chromium(III), and chromium(VI). None of these forms have any known taste or odor. Chromium compounds are used in the industrial manufacture of chrome plating, manufacture of dyes, and wood preserving.

Lead

Lead was detected in off-site wells as high as 19.8 ppb, and on-site as high as at 87.3 ppb.

There are no regulations for lead in private wells, however, the EPA has developed an action level of 15 ppb.

Lead in private drinking water is probably due to lead plumbing fixtures in individual homes and unlikely to be site-related. Although not likely to cause adverse health effects alone, long term exposure to lead in drinking water would contribute significantly to the overall body burden of lead. This could increase the lead exposure in individuals at risk for lead toxicity due to other sources (lead-based paint, food, and soil). Children under the age of six are at greatest risk for lead poisoning.

Studies indicate that long term exposure to low levels of lead can cause brain damage and lowered Intelligence Quotient (I.Q.). Lead exposure can increase blood pressure in middle-aged men. If a pregnant women is exposed to lead in drinking water it can be carried to the unborn child and may have an adverse effect on the mental development of the fetus.

Carcinogenicity Classification:
Lead has been classified by the EPA as a probable human carcinogen (EPA group B2). There is insufficient information to calculate cancer risk estimates for individuals potentially exposed via contaminated drinking water.

Brief Description of Chemical:
Lead is a naturally occurring gray metal detected in small quantities in the earth's crust. This compound has no taste or odor. Lead is used in the manufacture of batteries and in lead solder. However, as of 1986, the U.S. Congress banned the use of lead solder containing more than 0.2 percent lead. When water stays in pipes containing lead or lead containing plumbing systems for several hours the lead in the pipes or solder may dissolve into your drinking water.

Manganese

Exposure to manganese occurred in the past to persons who drank from contaminated private wells for 19 years. The maximum concentration detected was 530 ppb. Since there is no chronic MRL, the calculated dose from the maximal concentration of 530 ppb has been compared to a reference dose. Using the highest manganese concentration detected in the wells (530 ppb), the ingestion exposures were calculated for adults (0.015 mg/kg/day) and children (0.053 mg/kg/day). The RfD for manganese is 0.005 mg/kg/day. This value was exceeded. Consequently, we reviewed human investigations examining the health effects of prolonged exposure (50 years) to manganese in drinking water. From these studies, there is evidence to conclude that water contaminated with manganese at 530 ppb may represent an increase risk in non-cancerous adverse health effects. These risks may be characterized as low for adults, and moderate for children.

Investigations in humans and in animals indicate that neurologic effects may include: weakness, fatigue, tremors, ataxia (inability to coordinate muscle movement), and altered ability to walk (11, 31).

Carcinogenicity Classification:
Manganese is not currently classified by the EPA regarding its carcinogenicity.

Brief Description of Chemical:
Manganese is a naturally occurring compound detected in many rock formations. This element is similar in chemical and physical properties to iron. Manganese has numerous industrial uses including the formation of batteries and ceramics.

Methyl Tertiary Butyl Ether (MTBE)

MTBE was detected at levels in two private wells maximally at 250 ppb. The presence of MTBE is not related to the Linemaster Switch Site. MTBE exposure through ingestion and potentially through inhalation occurred in the past to persons who drank water from contaminated private wells.

Using the highest MTBE concentration detected in the wells (250 ppb), the ingestion exposures were calculated for adults (0.007 mg/kg/day) and children (0.025 mg/kg/day). There is no chronic MRL, however, the intermediate MRL for MTBE is 0.3 mg/kg/day. Since the intermediate MRL was not exceeded, non-cancerous adverse health effects are unlikely for adults or children who drank contaminated water for up to one year. The duration of exposure to MTBE is assumed to be similar to that of the benzene exposure duration of 4 years. The duration of potential exposure is likely to have been from 1988 through 1991. For exposures beyond one year, we examined the EPA longer-term health advisory. The longer-term health advisory is a concentration that both adults and children could be exposed to for up to seven years without any adverse health effects. Since the EPA longer-term health advisory was not exceeded, non-cancerous adverse health effects are unlikely for adults or children who drank water contaminated with MTBE at the maximum concentration for the entire exposure duration of four years.

Carcinogenicity Classification:
MTBE is categorized by the EPA as a group D chemical. A group D chemical in one which is not classifiable as to human carcinogenicity.

Brief Description of Chemical:
MTBE is a man made flammable liquid with an unpleasant odor. MTBE is now added to some gasoline formulations in an effort to reduce pollutants such as carbon monoxide. Additionally, this compound is used in medicine and industry.

Nickel

Exposure to nickel occurred in the past to persons who drank from contaminated private wells for 19 years. The maximum concentration detected on-site was 367 ppb. Using the highest nickel concentration detected in the wells (367 ppb), the ingestion exposures were calculated for adults (0.01 mg/kg/day) and children (0.037 mg/kg/day). These values are usually compared to MRLs. However, there are no chronic, intermediate, or acute MRLs for nickel to compare with these ingestion exposures. The RfD is 0.02 mg/kg/day. Although the RfD was exceeded slightly for children, the non-cancerous effects are low for children, and minimal for adults who drank water contaminated with the maximum nickel concentrations detected on-site (367 ppb).

Carcinogenicity Classification:
Nickel is categorized by the EPA as a group D chemical. A group D chemical in one which is not classifiable as to human carcinogenicity.

Brief Description of Chemical:
Nickel is a silver-white hard metal that is often combined in mixtures called alloys. Stainless steel, jewelry, and coins are important uses for nickel.

Tetrachloroethylene (PCE)

PCE exposure occurred in the past to people who drank water from contaminated private wells for 19 years. Using the highest PCE concentrations detected in the wells (430 ppb) the ingestion exposures calculated for adults (0.0123 mg/kg/day) and children (0.043 mg/kg/day) do not exceed the ATSDR intermediate MRL (0.1 mg/kg/day). Therefore, non-cancerous adverse health effects are unlikely to occur in those persons who drank PCE contaminated water for one year. For exposures beyond one year, we lack sufficient information to conclude if health effects may occur. The maximum concentration exceeds the EPA established MCL for PCE of 5 ppb. Consequently, if the maximum level detected in private wells was detected in a public water supply these levels would not be permitted for drinking or cooking.

Carcinogenicity Classification:
PCE was classified as a probable human carcinogen (EPA group B2). Currently, however, this classification has been withdrawn, and a review of this compound is being conducted by the EPA (9). Although the review is not yet complete, we calculated cancer risks for adults and children using available information from the Environmental Criteria and Assessment Office of the U.S. EPA (37). The longest period of time children and adults may have been exposed to PCE is 19 years. Consequently, we utilized this value in our estimates. When animals were exposed to very high levels of PCE there was an association with an increased incidence of liver cancer.

The estimated cancer risks were calculated using the highest PCE concentration detected (430 ppb). The cancer risk estimates calculated for a nineteen year period indicate that there is a moderate increased risk for developing cancer possibly including liver cancer.

Brief Description of Chemical:
PCE is a synthetic compound used as a metal degreaser and fabric dry cleaner. PCE is nonflammable liquid with a sweet odor. There are no natural sources of PCE.

Vinyl Chloride

Exposure to vinyl chloride occurred in the past to persons who drank from contaminated private wells for 19 years. Using the highest vinyl chloride concentration detected in the wells (0.89 ppb) the ingestion exposures calculated for adults (0.000025 mg/kg/day) and children (0.000089 mg/kg/day) do exceed the ATSDR chronic MRL (0.00002 mg/kg/day). Although the MRL was exceeded, the maximum concentration was below the EPA longer-term health advisory. For exposures beyond seven years, we lack sufficient information to conclude if health effects may occur. The maximum concentration is below the EPA established MCL for vinyl chloride of 2 ppb. Consequently, if the maximum level detected in private wells was detected in a public water supply these levels would be permitted for all drinking, cooking, and bathing needs.

Carcinogenicity Classification:
This compound is a known human carcinogen, (EPA group A). Most of the information about this compound has been obtained from inhalation exposures. Consequently, there is insufficient information to calculate cancer risk estimates for individuals potentially exposed via contaminated drinking water. When workers were exposed to this compound at high levels, there was a greater than expected incidence of liver cancer (33).

Brief Description of Chemical:
Vinyl chloride is a colorless vapor that has a sweet odor. This compound is man made and may be detected in groundwater as a result of the breakdown of TCE or PCE. Vinyl chloride is used in the formation of plastics such as polyvinyl chloride.

B. HEALTH OUTCOME DATA EVALUATION

The toxicologic evaluation of the ground water data suggest that persons who received ingestion exposures to water contaminated with TCE and arsenic, may be at an increased risk of developing cancer. The CT DPHAS conducted a review of cancer occurrence in Woodstock to assess if there was an increase in disease.

Information on the number of cancer cases in Connecticut and in Woodstock was obtained from the CT DPHAS, Tumor Registry. Information on the occurrence of cancer in Woodstock was obtained on the following tumor types: bladder, colon, kidney, leukemia, lung, melanoma, rectum, and all sites combined.

Since 1935, all tumors diagnosed to Connecticut residents are required by law to be reported to the Tumor Registry. Therefore, by reviewing data in the Tumor Registry we are able to make comparisons between the rates of cancer in specific towns with the rate of cancer in the State of Connecticut.

Age-specific cancer incidence rates were generated for Connecticut and Woodstock in five year periods for the thirty four year period from 1958 to 1991. The age-specific rates were calculated by dividing the number of cases identified during each five year period in an age group by the population in that age group according to the census (or an average for between census periods).

The standard incidence ratio (SIR) is an overall summary measure of the cancer risk. The SIR is calculated by multiplying the Connecticut cancer incidence rates by the population of the town to estimate an "expected" number of cancers in each age group. The actual (or observed) number of cases identified by the Tumor Registry are divided by the expected number to obtain the SIR. When the SIR is less than one (1.00) the risk of cancer is less than expected, when the SIR is greater than one the risk is more than expected. When the range of the 95% Confidence Interval (95% CI) does not include the number 1.00 then the results are considered to be statistically significant. This method allows for the inclusion of age as a risk factor in the analysis. Age is important to consider because, in general, the risk of cancer varies with age.

The rates of cancer incidence in Woodstock, CT are what would be expected based on State rates for the majority of the cancer sites studied. The overall rate of cancer (or total of all cancer types combined) and the rate of bladder cancer were actually lower in Woodstock than the state. The results are summarized in Table 9.

Table 9
CANCER INCIDENCE IN WOODSTOCK
IN COMPARISON TO CONNECTICUT 1958 TO 1991

* These Standard Incidence Ratios (SIR) are statistically significantly less than State rates for the same time period.

This review presents cancer rates in Woodstock in comparison with cancer rates for the State of Connecticut.

The overall rate of cancer in Woodstock was less than the State of Connecticut for the years 1958 to 1991. Bladder cancer also occurred less frequently than would be expected based on State rates. This type of data analysis does not gather information on any individual risk factors and does not allow any conclusions to be drawn regarding the cause of any specific types of cancer.

A review of birth records for Connecticut and Woodstock indicated that there is a lower incidence of low birth weight (defined as weighing below 2,500 grams at birth)in Woodstock in comparison to State rates. For the period 1979 to 1988, 20 of 624 births to Woodstock residents weighed below 2,500 grams for a rate of 4.6 per 100 births. For the same period the low birth weight rate among all races in Connecticut was 6.7 per 100, and approximately 5.5 per 100 among white Connecticut residents.

Eleven off-site residential wells were contaminated with TCE from Linemaster. This is too small a number of persons to conduct a more detailed evaluation of cancer or low birth weight in relations to exposure to TCE. A more complete study of cancer or birth weight would require acquisition of personnel records of Linemaster and Town Hall employees and crossing these records with the Tumor Registry and Vital Records from DPHAS. At this point in time a more extensive study of cancer incidence or the occurrence of low birth weight is not planned. See Table 8 for a depiction of the location, type of property and estimated number of persons exposed to PCE or TCE above the comparison values.

C. COMMUNITY HEALTH CONCERNS EVALUATION

We addressed the community concerns about health as follows:

1. Does itching skin after bathing indicate that the well is contaminated or has been re-contaminated?

Studies indicate that bathing with water contaminated with arsenic and TCE can cause itching and other skin ailments. These symptoms are more likely to occur at contamination levels higher than those identified in the private water wells. TCE is currently being filtered out of the water. Certain individuals may be more sensitive to the effects of arsenic and their itching skin may be the result of exposures to this element.

2. Could dizziness, fainting, and a feeling of weakness be related to exposures connected with the Linemaster Switch site?

The contaminants evaluated in this health assessment occur at levels that would not cause dizziness, fainting or a feeling of weakness in the general population. However, some people are more sensitive to chemicals than others. We recommend that you see a physician about the symptoms expressed above.

3. Is it safe for farm animals such as cattle to drink water contaminated by the Linemaster Switch or the water that was contaminated by the Woodstock school leaking fuel tank?

Currently we have no evidence that livestock in the area are being exposed to contaminated water. However, if a well that is used for livestock is found to be contaminated, the CT DPHAS recommends the installation of a water treatment system.

4. Are the levels of arsenic in some wells safe? What are the health effects of arsenic in drinking water?

As previously discussed in the Public Health Implications section, levels of naturally occurring (not related to Linemaster Switch) arsenic have been detected in private wells above health comparison values and non-cancerous health effects are possible. Persons exposed to high arsenic levels in drinking water may be at an increased risk of developing cancer.

Therefore, we recommend to those residents whose wells have been found to have arsenic levels above the recommended health values to treat their well water to remove the arsenic.

5. Could Grave's disease result from exposures to the contaminants found in the drinking water?

A review of the literature (15, 16, and 17) on the causes of Grave's disease indicates that it is an autoimmune thyroid disease caused by: a genetic predisposition; the presence of thyroid-stimulating immunoglobulin; and in some cases the cause may be uncertain. Stress is believed to play a major role (15,17). In some cases the onset of the disease follows a frightening episode in the patients life, or the loss of a loved one.

Because Grave's disease is an autoimmune disease, we reviewed the immunological effects of those contaminants found in drinking water wells more closely. The immunological effects in humans related to ingestion exposures to the contaminants identified in the drinking water wells have been reported and are controversial. Benzene has been found to effect the immune system of laboratory animals at levels much higher than those identified in the benzene contaminated drinking water wells. In addition, there is evidence that chronic exposure to mixed solvents (including TCE and PCE) in drinking water can produce some autoimmune effects (18,19). This is supported by a study in mice exposed to a mixture of solvents in drinking water (20).

6. Because of the on-site ground water recovery system wells residents are concerned that their wells may run dry.

Two wells in the area have run dry. The CT DEP and Linemaster Switch have responded in a timely manner to correct the situation. One resident's well was replaced. The other resident's well needed a new sediment filter.

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