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PUBLIC HEALTH ASSESSMENT
ACME SOLVENT RECLAIMING, INC.
WINNEBAGO, WINNEBAGO COUNTY, ILLINOIS


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

The tables in this section list the contaminants of concern. These contaminants will be further evaluated in the remaining sections of this health assessment to determine if they pose a threat to public health. The listing of a contaminant on the following tables does not necessarily mean that the contaminant poses a threat to public health. The selection of these contaminants is based on the following factors:

  1. Concentrations of contaminants on and off the site.
  2. Data quality, both in the field and in the laboratory, and the sampling plan design.
  3. Comparison of contaminant concentrations and background concentrations with health assessment comparison values for both carcinogenic and noncarcinogenic endpoints (discussed further below).
  4. Community health concerns

Comparison values for health assessment are levels that are used to select contaminants for further evaluation. These values, prioritized and described below, include Environmental Media Evaluation Guides (EMEGs), Cancer Risk Evaluation Guides (CREGs), Reference Dose Media Evaluation Guides (RMEGs), Lifetime Health Advisories (LTHAs), and Maximum Contaminant Levels (MCLs). If a site-related contaminant is discovered at levels above any of these comparison values or if no comparison values exist for the chemical, it will be investigated further in the remaining sections of the health assessment to determine if it poses a significant threat to public health. Known or suspected human carcinogens for which no carcinogenic comparison value exists will also be listed as a contaminant of concern and will be evaluated in the remaining sections of this health assessment.

EMEGs are comparison values developed by ATSDR for chemicals that are relatively toxic, frequently encountered at NPL sites, and present a potential for human exposure. They are derived to protect the most sensitive members of the population (e.g., children and the elderly) and are not cut-off levels, but rather comparison values. They do not consider carcinogenic effects, chemical interactions, multiple route exposure, or other media-specific routes of exposure, and are conservative concentration values designed to protect the public.

CREGs are estimated contaminant concentrations based on a one excess cancer in a million persons exposed to a chemical over a lifetime (70 years). These are also conservative values designed by ATSDR to protect sensitive members of the population.

RMEGs are ATSDR comparison values based on USEPA's RfDs or Reference Concentrations (RfCs). These values are estimates of a daily oral or inhalation exposure to a particular chemical that is not likely to produce any noncarcinogenic adverse health effects over a lifetime. These numbers may be adjusted to protect sensitive members of the population.

USEPA's LTHAs are concentrations to which an individual can be exposed through drinking contaminated water for 70 years without experiencing any noncarcinogenic health effects. These numbers contain a margin of safety to protect sensitive members of the population. These values are only considered if no EMEG, CREG, or RMEG values are available for the chemical.

MCLs have been established by USEPA for public water supplies to reduce the chances of adverse health effects from contaminated drinking water. These standards are well below levels for which health effects have been observed and take into account the financial feasibility of achieving specific contaminant levels. These are enforceable limits that public water supplies must meet. These values are only considered if no EMEG, CREG, RMEG, or LTHA values are available for the chemical.

A. On-Site Contamination

Two environmental investigations have been performed at this site since its proposed inclusion on the NPL in 1982. A Remedial Investigation (RI) was conducted in 1984-85 and demonstrated on-site soil and area groundwater contamination with several organic compounds. Following the RI in 1986 some on-site soil remediation was performed by the PRPs without IEPA or USEPA's oversight. These activities included the removal and disposal of approximately 46,800 tons of contaminated soil. Since no USEPA oversight was sought, a Supplemental Technical Investigation/Endangerment Assessment (Supplemental Investigation) was performed after the soil remediation. This investigation, conducted 1987-89, demonstrated some remaining soil contamination as well as continued area groundwater contamination. An estimated 4,000 tons of contaminated soil and two tanks containing contaminated liquids and sludges still remain on-site.

Soil: During the RI in 1984, on-site soils were sampled for metals and organic compounds including PCBs, VOCs, and pesticides. The wastes found on-site were generally confined to eight areas (Figure 3). These areas were the locations of the former lagoons where sludges, wastes, and drums were buried. Three compounds, however, isophorone, naphthalene, and bis(2-ethylhexyl)phthalate were found widely distributed in soils throughout the site. PCB contaminated soil was discovered on-site, the majority of which was found in buried sludges near the southwestern edge of the site. Lead was also detected in several samples. Since no comparison value exists for lead in soil, it will be considered as a contaminant of concern. See Table 1 for a complete list of contaminants of concern detected in on-site soils in 1984.

In 1986, remediation work began to remove contaminated soils for off-site disposal. A diagram of the waste deposition areas at ACME is shown on Figure 3. This diagram was taken from a report prepared by Environmental Resources Management (1986) detailing the progress of cleanup activities at ACME by representatives of the PRPs in 1986. Included in this diagram is an approximation of the amount of contaminated soils removed from each area and an estimate of the amount of contamination that remained on-site. Cleanup activities halted soon after the issuance of this progress report. According to IEPA, 10 percent of the original contamination currently remains on-site.

During the Supplemental Technical Investigation (1987-1989) conducted by the PRPs with IEPA and USEPA oversight, soils within and surrounding the excavated mounded areas were sampled in order to determine the extent of the soil contamination remaining on-site. A summary of the results is shown in Table 2. Several organic compounds were detected at low levels during the Supplemental Investigation. Most of the contamination on-site was confined to two sample locations, and depths of 7-12 feet, near the southwest edge of the site. Of the compounds detected, 1,1,1-trichloroethane, 4-methyl-2-pentanone,benzo(b)-fluoranthene, 2-methylnaphthalene, and phenanthrene will be considered as contaminants of concern since no comparison values currently exist for these chemicals in soil. PCBs and bis(2-ethylhexyl)phthalate were again detected above levels of concern and appear to be the main contaminants of concern remaining in on-site soil. Lead was detected in all of the soil samples taken during the Supplemental Investigation. Since no comparison value exists for lead in soil, it will be considered as a contaminant of concern.

The IEPA performed a CERCLA Screening Site Inspection (CSSI) at the Acme site during May 1993. A summary of the results of the on-site soil sampling is shown in Table 3. Most of the organic contaminants were either detected in the three soil samples collected inside the Acme building in the trench cut in the concrete floor or in the sample taken about 8 feet east of the building and about 10 feet south of the loading ramp (X-107, Figure 5). The inorganic compounds detected were below or near background levels.

In October of 1993, further on-site soil remediation was begun by USEPA's general contractor (Westinghouse). Their job was to decontaminate identified areas of contaminated soil. The contaminated areas were excavated, reportedly in some areas down to 10 feet, the soil was then run through a large furnace and the fumes were collected and run through carbon scrubbers. The soil was then placed back into the original excavation. All process water was treated and recycled. In the year that they have been on site, they have processed over 6,000 tons of contaminated soil (5).

Groundwater: Contaminants were detected in on-site monitoring wells during the RI (1984), Supplemental Investigation (1987-89), and CSSI (1993). See Tables 4, 5, and 6 respectively for sample results. The chemicals most frequently detected in the groundwater are the chlorinated organic compounds. These compounds have been detected in a total of 43 groundwater monitoring wells surrounding ACME and Pagel's Pit. The highest level of contamination has been found near the southern and western edges of the ACME site. Several of these compounds, vinyl chloride, 1,2-dichloroethane, 1,2-dichloroethylene, tetrachloroethylene, trichloroethylene, and 1,1,2-trichloroethane appear to be the main contaminants of concern in groundwater around the ACME site. Organic contaminants were also detected in monitoring wells located on and around Pagel's Pit.

On October 27, 1994, an ECI representative indicated that as part of the groundwater remediation project ECI will be drilling 16 extraction wells and constructing a water treatment facility (16). The treated water will be discharged to a surface ditch. The length of time the treatment facility will remain operational will depend on the extent of groundwater contamination.

Surface Water: Surface water draining from the site flows toward an intermittent creek that runs along the southern boundary of the site (Figure 4). During the E.C. Jordan RI, four surface water and sediment samples were collected from points along the creek. These samples were analyzed for metals, cyanides, sulfides, and volatile and semi-volatile compounds. The metals were detected at concentrations within the established background levels and cyanides and sulfides were not present at or above the laboratory detection limits (only data summary available). In addition, no organic compounds were detected in the surface water or sediment samples.

Air: Air sampling was performed prior to and during RI invasive work. Air samples were collected and analyzed using an organic vapor analyzer (OVA) to identify volatile organic compounds. Several organic compounds were detected during both sample times at concentrations below public health concern. No compounds were detected above the threshold limit values (TLVs) established by the American Conference of Governmental Industrial Hygienists (ACGIH). TLVs are concentrations at which no adverse health effects would be expected from exposure in an occupational setting eight hours a day, forty days a week. One compound, tetrachloroethylene (.1-1.10 parts per million (ppm)), was detected above the EMEG for air (.009 ppm) before and during the invasive work.

Also, several air samples were collected from barrel vapors and soil headspace in areas of contamination. The levels of total VOCs detected in these samples ranged from 1.1 to 5,685 ppm.

In addition to the above mentioned groundwater remediation project, ECI will also be constructing a soil vapor extraction system (16). In a 40,000 square foot area, identified by USEPA, a series of three trenches will be constructed. These trenches will be placed under vacuum and the vapors will be treated with carbon filters.

B. Off-Site Contamination

The major contaminants of concern in area groundwater appear to be several of the chlorinated solvents (Table 5). The contamination of several residential wells near the ACME site was discovered in 1981 by the WCHD. The WCHD sampled 11 private wells surrounding ACME for VOCs. The sample results showed that five of these wells were contaminated with varying levels of several VOCs.

The locations of the five contaminated wells are shown on Figure 4, and are identified by the letters E-H, and P. Soon after the contamination was discovered, the owners of Pagel's Pit drilled a new well to replace contaminated wells F and P (owned by Pagel's Pit). No remedial action was taken on the three remaining contaminated wells.

In 1984, the private wells were resampled as part of the E.C. Jordan RI activities. Results of the sample analyses showed that only wells E, F, and G had detectable levels of VOCs. In addition, the average levels of contaminants appeared to have decreased since the 1981 sample period.

In 1986, the PRPs agreed to provide whole-house carbon filter units for residential wells G-L. According to the IEPA, the PRPs have been routinely sampling the residential wells for VOCs since they were installed in February 1987. A summary of the available residential well data is shown in Table 7. As the table shows, the average level of contamination in the residential wells appears to have decreased since sampling began in 1981. These wells are located and are identified in Figure 4. Three homes on Lindenwood Road are currently using the whole-house carbon filter units. In addition, three other residential wells are being monitored. Sample results from these monitored wells have indicated trace levels of VOCs. According to IEPA, only one violation of an MCL for either TCE or PCE has been reported during the well monitoring and that resident was notified.

At the request of the USEPA, ATSDR reviewed the residential water-supply well analytical data for the quarterly sampling from August 1991 to November 1993 (3). ATSDR reported that the concentrations of sodium in water from several carbon filter units exceeded USEPA's Drinking Water Equivalent Level of 20 ppm. Although sodium was detected at levels ranging from 147 - 442 ppm, no other contaminants were detected at levels of public health concern. ATSDR recommended that the residents be warned that sodium in their drinking water is of particular concern to hypertensive individuals and to those persons who are on sodium restricted diets (3). According to USEPA, it has been determined that all homes that have home carbon treatment units are being provided with bottled drinking water by the PRPs (18). Reportedly, the problems with sodium have been discussed with the PRPs and they are considering various options to address them.

C. Quality Assurance and Quality Control

In preparing this public health assessment, IDPH relies on the information provided in the referenced documents and assumes that adequate quality assurance and quality control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. Inadequate information was provided by Harding Lawson Associates to IEPA and USEPA during and following the August through December 1986 site soils remediation according to IEPA file records. The validity of the analysis and conclusions drawn for this health assessment is determined by the availability and reliability of the referenced information. Quality Assurance and Quality Control documents were unavailable to IDPH reviewers at the time this Health Assessment was prepared.

D. Physical and Other Hazards

ACME Solvent is located in an area surrounded by heavily wooded fields. There is a locked gate at the entrance road leading onto the site. Although, the site is surrounded by a barbed wire farm fence, the site is easily accessible by foot. There are no apparent physical hazards on-site.

E. Toxic Chemical Release Inventory

Since the reporting of toxic chemical releases began in 1987, the USEPA has collected information on estimated annual releases of toxic chemicals by industry to the environment (air, water, land, or underground injection). This data is compiled and retrievable through the on-line database, Toxic Chemical Release Inventory (TRI). The reporting years of 1987, 1988, 1989, and 1990 are currently available for review.

The TRI records were reviewed for reporting industries in the vicinity of the site. No industries within a 3-mile radius reported releases of chemicals to the environment. This was anticipated since land use around the site is primarily agricultural or residential.

PATHWAYS ANALYSES

In order to determine whether or not residents around a hazardous waste site have been, are being, or may be exposed to hazardous chemicals migrating from the site, IDPH evaluates the surrounding environmental conditions and local human activities that may lead to exposure. Generally, this information is evaluated for five criteria which represent the parts of an exposure pathway. These five criteria include:

  1. a contaminant source,
  2. an environmental transport pathway (e.g., groundwater),
  3. a point of potential exposure (e.g., private well),
  4. a route of exposure (e.g., ingestion of contaminated groundwater), and
  5. a receptor population or people who may be exposed.

An exposure pathway is considered as complete, potential, or incomplete based on the status of the above criteria. If all five criteria exist for a particular exposure pathway, then it is considered to be complete and indicates that exposure to contaminants has occurred, is occurring, or will occur in the future. A potential exposure pathway is one in which at least one of the five criteria is absent, but could exist. This indicates that past exposure may have occurred, may be occurring now, or may occur in the future. Incomplete pathways include those for which one of the above criteria is absent and will never be present. An exposure pathway can be eliminated if the pathway is considered incomplete.

The estimated population for completed and potential exposure pathways is confined to the 24 residences (60-70 people) living within a 1/2-mile radius around the site and an unknown number of past ACME employees, remediation workers, and individuals which have or may gain access to ACME property and Killbuck Creek. The site began operation in 1960 and operated until 1973. Soil contamination was partially remediated by 1986. Completed and potential exposure pathways that are important and relevant to the site are listed in Tables 8 and 9 respectively and are discussed below in detail.

A. Completed Exposure Pathways

Surface Soils

Based on the soil sampling conducted in 1987 by Harding Lawson Associates, remaining contaminated soil is confined primarily to the southwest edge of the site at depths of 7-12 feet. Prior to the 1986 site remediation on-site soils were contaminated with numerous inorganic and organic compounds (Table 1). These contaminated soils were a likely source of the contaminated groundwater, since VOCs move through most soils with little retardation. The most recent soil sampling data shows that contaminants still remain in the on-site subsurface soils, these soils will continue to be a source for the release of contaminants into the groundwater.

Prior to the 1986 remediation activities, ACME workers and site-trespassers may have been exposed to contaminated surface soils through dermal contact with the contaminated soils, inhalation of wind-blown contaminated dust, and incidental ingestion of contaminated soils. Human exposure to contaminated soil may also have occurred to on-site workers during the 1986 remediation activities. Although the site, currently, is easily accessible (trespassers, children, etc.), the surface soil is not a public health concern. Most of the contamination is associated with buried sludge/waste. These wastes are confined to soils at depths ranging from 7-12 feet. In addition, as mentioned previously, the site surface soils have a heavy vegetative covering, limiting direct contact with soil.

Groundwater

The most significant route of human exposure at the ACME site is domestic use of contaminated groundwater. Based on the available information, the flow of groundwater from ACME is providing a transport pathway for the release of contaminants off-site. A contaminant plume migrating from ACME has been identified and is moving to the south-southwest with the flow of groundwater.

The locations of the nearby residential wells are shown on Figure 4. The 1981 residential well sample results showed that several wells were contaminated with total VOCs in excess of 400 parts per billion (ppb). However, subsequent sampling data collected since 1981 has shown a continual decline in the levels of contaminants in the residential wells. Table 7 shows sampling dates, compounds found, concentrations detected, and comparison values. The residential well sampling data from 1987-1989 have shown that contaminants are present in two wells that had not previously shown contamination. These sampling data suggest the contaminant plume may be migrating further to the south.

With the exception of vinyl chloride, 1,1-dichloroethylene, chrysene, and benzo(a)anthracene, the average levels of contaminants detected in the most recent residential well sample analyses are below current public health standards and guidelines. However, these sample results do indicate two potential changes in the groundwater contamination pattern. First, as discussed previously, the contaminant plume appears to be migrating further south and could potentially affect homes not previously contaminated. Second, new contaminants of potential public health concern; vinyl chloride, 1,1-dichloroethylene, benzo(a)anthracene, and chrysene were detected in one of the residential wells. Although vinyl chloride may be a primary site-related contaminant, it is also generally believed that vinyl chloride may be the ultimate product formed in the degradative pathway of chlorinated ethylenes in groundwater.

The investigation of the groundwater contamination problem in the area is confounded by the presence of the Pagel's Pit Landfill. Many of the same contaminants found at ACME have also been detected in Pagel's Pit monitoring wells and leachate samples. Based on the available information, it is likely that both Pagel's Pit and ACME Solvent are contributing to the groundwater contamination problem in the area.

Domestic use of contaminated water results in human exposure to VOCs. There are various household activities which contribute to an individual's overall exposure to these compounds. Exposure to contaminated water can include: ingestion of contaminated water while drinking and cooking with the water; dermal contact and absorption while bathing, showering, or general water use; and inhalation of aerosolized or volatilized contaminants during showering or during other uses of the contaminated water.

The primary food crops grown in the area are soy beans and corn. It is generally believed that area groundwater is not used for crop irrigation. However, even if area crops are irrigated, contamination of the food chain by site-related contaminants does not appear to be a significant pathway for exposure. At the levels found in private wells, plant uptake of volatile compounds to levels of public health concern is not likely to occur. These compounds generally would not persist in surface soils and they do not bioaccumulate in plant or animal tissues.

Air: Based on the available information, contaminants at ACME are associated with sludge/waste in soils. Prior to the 1986 remediation activities, release of contaminants into the air could occur through volatilization and generation of dusts containing adsorbed contaminants. The VOCs are the compounds most likely to be released into the air through volatilization. Air sampling performed prior to and during the 1984 RI invasive work detected several VOCs in the ambient air. The metals and semi-volatile compounds on-site are more likely to be released into the atmosphere through fugitive dust generation.

The site has remained undisturbed since the remediation activities of 1986. The majority of remaining contaminants are found primarily at depths of 7-12 feet. Heavy vegetation currently covers the site, which should act to keep dust generation to a minimum, thereby restricting the release of remaining metals and semi-volatile compounds into the atmosphere. This heavy vegetation should also help to keep volatilization of compounds to a minimum. However, during remedial activities, particularly excavation of contaminated soils, there is the potential for contaminant release through increased generation of dusts.

As discussed previously, VOCs were detected in air monitoring samples collected during 1984 RI activities. However, air monitoring stations located outside of the ACME site boundaries failed to detect significant levels of VOCs. The nearest home is located a quarter of a mile outside of the ACME site boundaries. Given this distance and the level of VOCs that have been detected in air samples, it is unlikely that air is a significant route of exposure to nearby residents. Although the site is easily accessible (trespassers, children, etc.), human exposure to contaminated soil is not likely to occur to a significant degree. Most of the contamination is associated with buried sludge/waste. In addition, as mentioned previously, the site surface soils have a heavy vegetative covering, limiting direct contact with soil.

B. Potential Exposure Pathways

Subsurface Soils: Based on the soil sampling conducted in 1987 by Harding Lawson Associates, remaining contaminated soil is confined primarily to the southwest edge of the site at depths of 7-12 feet. Subsurface soil samples collected from areas previously excavated in 1986 showed sporadic detections of several VOCs and semi-volatile compounds. These compounds were primarily detected in one soil sample taken from section 4 of the site (shown on Figure 3). Given the depth of contamination and the heavy vegetative covering, the release of these compounds into the atmosphere is not likely to occur to a significant degree.

The most likely environmental transport pathway from remaining contaminated soils is the movement of these contaminants into the groundwater. VOCs move through most soils with little retardation, and therefore, would be expected to infiltrate into the groundwater. Since the most recent soil sampling data shows that contaminants still remain in the on-site soils, these soils will continue to be a source for the release of contaminants into the groundwater.

Human exposure to contaminated soil would most likely occur to on-site workers during remediation activities. Although the site is easily accessible (trespassers, children, etc.), human exposure to contaminated soil is not likely to occur. Most of the contamination is associated with buried sludge/waste. These wastes are confined to soils at depths ranging from 7-12 feet. In addition, as mentioned previously, the site surface soils have a heavy vegetative covering, limiting direct contact with soil.

Surface Water/Sediment: Surface water runoff from the site flows to the south, toward the intermittent creek located along the southern boundary of ACME. Prior to the 1986 remediation activities, metals and semi-volatile contaminants adsorbed to soils could be carried off-site with the flow of surface water. However, in 1984, surface water/sediment samples taken at points along the Killbuck Creek failed to detect metals at levels above the calculated background ranges. In addition, no organic compounds were detected in these samples. Therefore, surface water runoff does not appear to be a significant transport pathway for the release of contaminants off-site.

Contaminants were not detected in surface water and sediment samples taken from the intermittent creek running along the southern boundary of ACME. This creek is a tributary of the Killbuck Creek, located approximately one mile west of the site. The Killbuck Creek is used primarily for sport fishing, but not as a potable water supply. According to the hydrogeological information gathered during the supplemental RI (Harding Lawson Associates), Killbuck Creek receives some discharge from the upper sand and gravel aquifer, although the majority of the groundwater is shunted under the river. Therefore, it is possible that contaminants in the groundwater could enter the Killbuck Creek through groundwater discharge. Although it is not likely that contaminants would have a significant impact on the creek, humans could potentially come in contact with small amounts of the compounds through incidental ingestion of creek water, inhalation of volatilized compounds, and dermal contact with creek water.

Aquatic Biota. According to the hydrogeological information gathered during the Supplemental Technology Investigation, Killbuck Creek receives some discharge from the upper sand and gravel aquifer, although the majority of the groundwater is shunted under the river. Therefore, it is possible that contaminants in the groundwater could enter the Killbuck Creek through groundwater discharge. Given the distance from the site, small percentage of aquifer discharge to Killbuck Creek, and other dilutional mechanisms available, it is not likely that the contaminated groundwater would have a significant impact on the creek's aquatic biota.

PUBLIC HEALTH IMPLICATIONS

A. Toxicological Evaluation

As concluded in the previous Pathways Analyses Section, the most significant route of human exposure at the ACME site is the domestic use of contaminated groundwater. Exposure to contaminated groundwater has been documented through monitoring residential private wells. Other completed exposure pathways of importance, primarily from past exposure by ACME employees or remediation workers, include on-site contaminated soils and air. However, remediation workers were likely to wear personal protection gear sufficient to provide adequate protection against exposure. Potential exposure pathways of minor importance, primarily to very low-levels of contaminated media, include surface water and aquatic biota.

Although a variety of inorganic and organic compounds have been detected, the toxicological evaluations can be divided into concern from acute exposure (employees, remediation workers, and trespassers) for which most of the sources of exposure have been removed, and concern from chronic or longer term exposure to low-levels of contaminants in residential private wells.

The chemicals of health concern found in site-related contaminated media are primarily VOCs and semi-volatiles. These chemicals are all readily absorbed when inhaled or ingested. Dermal absorption is poor in contrast. However, the toxicity of each chemical is associated with the chemical-specific rate of biotransformation, and varies with species, strain, and sex.

To evaluate potential health effects, the estimated human exposure doses to site-related compounds have been compared with health effects information in the ATSDR Toxicological Profiles. ATSDR and USEPA have developed chemical-specific guidelines by which to evaluate the potential for adverse health effects from exposure to these chemicals in soil, air, and water. ATSDR has developed Minimal Risk Levels (MRLs) to evaluate non-cancer health effects. A MRL is an estimate of the daily human exposure to a contaminant below which non-cancer, adverse health effects are unlikely to occur. The exposure is expressed as milligrams of chemical per kilogram of body weight per day (mg/kg/day). MRLs are developed for the oral and inhalation routes of exposure, and for the length of exposure, such as acute (14 days or less), intermediate (15 to 365 days), and chronic (greater than 365 days). An USEPA Reference Dose (RfD) for non-carcinogens is an estimate of a daily exposure (mg/kg/day) to the general public that is likely to be without an appreciable risk of deleterious effects during a lifetime. The USEPA also has developed health advisories for exposure to contaminated drinking water for periods of one-day, ten-day, longer-term and lifetime exposures to non-carcinogens. The USEPA also evaluates a chemical's potential to cause carcinogenic (cancer) effects by estimating the risk of developing cancer over a lifetime. The USEPA has estimated cancer slope factors (CSF) for certain chemicals. These CSFs are estimates of the potency of a chemical to cause cancer and are used in conjunction with the exposure dose to estimate the cancer risk. Maximum Contaminant Levels (MCLs) are drinking water quality regulatory standards established by the USEPA for public water supplies to reduce the chances of adverse health effects from contaminated drinking water. These standards are well below levels for which health effects have been observed and take into account the financial feasibility of achieving specific contaminant levels. These are enforceable limits which public water supplies must meet.

The chemical-specific discussions which follow are limited to potential health effects that may occur at exposure levels similar to those found at this site. Estimations of exposure doses via ingestion in this assessment assume that adults drink 2 liters of tap water per day and children drink 1 liter of tap water per day. For noncarcinogens, ingestion assumptions for children were used because children receive a larger exposure dose since they ingest more liquid per body weight than adults. Inhalation of volatilized VOCs during showering, etc., is assumed to be equivalent to ingestion exposure. Estimation of exposure doses to contaminants in air and soil assume that workers were exposed five days a week, eight hours per day.

1. Chlorinated Solvents

Chloroethane

Chloroethane was detected in groundwater monitoring wells. It was not detected in residential wells. There are currently no health guidance levels for this chemical in food or water and the toxicological information on chloroethane is primarily limited to levels near or at those which produce anesthesia.

Limited evidence suggests that chloroethane is a fetotoxin when inhaled by mice at relatively high concentrations. Neurological symptoms have been observed in human case-studies in instances of chloroethane abuse. In animals it has been demonstrated to be a cardiac sensitizer, and cause liver enlargement and liver dysfunction, lowered blood pressure, and thickening of the lung lining.

Chloroform

Chloroform was detected in groundwater monitoring wells at levels below the intermediate MRL as calculated for a child. Chloroform is often a bi-product of chlorination of water. Results of studies in humans who drank chlorinated drinking water have shown a possible link between the chloroform in water and the occurrence of cancer of the colon and urinary bladder. The USEPA has labeled chloroform as a probable human carcinogen based on the inadequate human and sufficient animal data available. Even if residential wells become contaminated with chloroform at current monitoring well levels, lifetime consumption of the water would result in no apparent increased cancer risk from chloroform exposure.

1,1-dichloroethane

1,1-Dichloroethane was detected in groundwater monitoring wells and unremediated on-site soils at levels above the USEPA RfD. It has not been detected in residential wells. Toxicological information on 1,1-dichloroethane is very limited. Health effects via ingestion is limited to animal studies at high exposures. The available cancer studies in animals have been inconclusive due to study limitations and errors. A 1977 National Cancer Institute (NCI) study suggested that 1,1-dichloroethane can cause tumors in blood vessels, mammary glands, and uterus of rats and mice. Information on health effects via inhalation have only been at very high levels.

1,2-dichloroethane

1,2-Dichloroethane was detected in groundwater monitoring wells at levels above ATSDR's screening comparison values; however, it has not been detected in residential wells. Most of the available toxicological information on this chemical describes acute, high dose effects. Chronic, low dose animal studies have involved principally liver and kidney effects. Liver tumors have developed in rats following ingestion of low levels of 1,2-dichloroethane. The USEPA classifies it as a probable human carcinogen for both oral and inhalation routes of exposure.

1,1-dichloroethylene (DCE)

DCE was detected in unremediated on-site soils and the most recent residential well sampling and exceeded a screening comparison value for the compound in drinking water. The liver is the primary target organ of this chemical. The drinking water comparison value is way below the corresponding MRL which is based on the lowest observed adverse effect level of 9 mg/kg/day, corresponding to a concentration of 50,000 ppb in water. The effect was a minimal amount of liver cellular swelling and an increase in cellular liver fat. At higher doses an increase in serum enzymes, indicating liver dysfunction, may be seen. There is some evidence in animals that poor nutritional status increases DCE liver toxicity.

DCE is classified by the USEPA as a possible human carcinogen. This classification applies to chemicals for which there is limited evidence of carcinogenicity in animals. Contaminant levels seen in recent residential wells, consumed for a lifetime, may possibly result in a low increased risk of cancer.

There is no data to evaluate dermal contact or inhalation of vapors from soils. An intermediate inhalation MRL of 0.02 ppm has been developed from an animal study reporting a decrease in liver weight and fatty changes in the liver. The limited information on human exposure indicates that DCE is probably toxic to the human liver, although effective exposure doses are unknown.

USEPA has derived a cancer slope factor for inhalation of 1.2 (mg/kg/day)-1 based on an animal study reporting an increase in total mammary tumors. The lowest dose producing tumors (Cancer Effect Level) was 10 ppm. The study had a number of limitations, therefore, the evidence for carcinogenicity from inhalation exposure is considered to be inconclusive.

Health effects through dermal exposure cannot be estimated from the available information.

cis-1,2-dichloroethylene and trans-1,2-dichloroethylene

1,2-Dichloroethylene (no isomer identified in data) was detected in residential and monitoring wells at levels above the USEPA LTHA for this compound in drinking water. At detected levels, the estimated exposures for children would not exceed ATSDR's intermediate oral MRL for cis-1,2-dichloroethylene or USEPA oral RfD for trans-1,2-dichloroethylene. No other long-term health guidelines are available. Health effects through dermal exposure cannot be estimated from the available information.

1,2-dichloropropane

This compound was detected in both on- and off-site monitoring wells during the 1993 CSSI sampling at levels at and above the MCL for drinking water. It was not detected in the residential wells. 1,2-Dichloropropane can be absorbed after dermal contact, inhalation, or ingestion. After absorption, it is quickly eliminated from the body in breath, urine, and feces. Exposure by consumption of on- or off-site shallow groundwater would not exceed the chronic oral MRL, so no noncancerous health effects would be expected via this route. There is no cancer slope factor for this compound, so cancer risks cannot be evaluated. Mammary cancer has been observed in rats, and liver cancer occurred in mice after oral exposure to this chemical. However, the toxicological data are insufficient to estimate human cancer risks from specific exposures.

Methylene chloride

Methylene chloride was detected in unremediated on-site soils at levels up to 216 times above the ATSDR CREG and seven times greater than the calculated MRL for children, but not for an adult. Methylene chloride commonly affects the skin, respiratory system, and nervous system. Methylene chloride has been shown to cause an increased incidence of tumors in rats and mice. To date there is no evidence that methylene chloride causes cancer in humans. The USEPA considers the evidence provided by the animal studies sufficient to rank methylene chloride as a probable human carcinogen.

Information on dermal exposure to methylene chloride is limited to dermal/ocular effects in humans and animals from exposure as a vapor or liquid which causes burns at high levels.

Tetrachloroethylene (PCE)

PCE was detected in residential and groundwater monitoring wells at levels which exceeded the USEPA MCL. However, the levels do not exceed the oral MRL or the USEPA's oral RfD for either children or adults. In experimental animals, the liver is the primary target organ of PCE via ingestion. The lowest observed adverse effect level of 100 mg/kg/day has resulted in increased liver weight in mice. Higher levels will begin to cause liver necrosis and an increase in certain serum enzymes. The kidney is also a target organ for PCE but less sensitive than the liver.

The International Agency for Research on Cancer (IARC) has classified PCE soil as a possible human carcinogen. The USEPA does not currently have a cancer slope factor or a cancer classification for PCE. NCI conducted a carcinogenicity bioassay of rats and mice. No increases in tumor incidence were observed for the treated rats. Statistically significant increases in liver tumors occurred in the mice, however, the study had a number of limitations. These limitations included, a small control group, numerous dose adjustments during the study, early mortality, and pneumonia. The cancer potential of PCE remains a data gap.

Health effects through dermal exposure cannot be estimated from the available information.

1,1,1-trichloroethane

1,1,1-Trichloroethane has been detected in groundwater monitoring wells and remediated and unremediated on-site soils above levels of concern. Although not found in residential wells, levels in monitoring wells have exceeded the USEPA LTHA for the compound in drinking water. No other health guidelines are currently available for this compound. Toxicological information on 1,1,1-trichloroethane is limited, but existing studies indicate that high levels are required to produce adverse health effects. Slight to moderate reversible skin irritation has been seen in animal studies.

1,1,2-trichloroethane

1,1,2,-Trichloroethane was detected in residential and groundwater monitoring wells at levels above the ATSDR CREG. Monitoring well data indicates levels above the oral RfD for children, but not adults. There is no information on the health effects of exposure to 1,1,2-trichloroethane in water in humans. Animals exposed to high doses indicate that it might affect the liver, kidney, and digestive tract. There does not appear to be any evidence of birth or developmental defects.

There is no evidence for carcinogenicity of 1,1,2-trichloroethane in humans and only limited evidence in animals. The USEPA considers it as a possible human carcinogen.

Trichloroethylene (TCE)

TCE has been detected in residential wells, monitoring wells, and unremediated on-site soils above levels of concern. Both residential and groundwater monitoring wells have historically exceeded the USEPA regulatory standard (MCL) of 5 ppb. At the residential well levels, an estimated exposure for children would not exceed ATSDR's intermediate (15-365 days) oral MRL. No other long-term health guidelines are available.

Animal studies of intermediate length have shown some liver toxicity. The MRL is based on an increase in liver weight in mice. Long-term animal studies have not shown non-cancer liver lesions at low levels. TCE has been shown to cause liver tumors in mice.

Kidney damage has been shown in long-term animal studies, but not in studies of short or intermediate length. Kidney tumors were also reported in these same studies, however, the studies are considered to be flawed because of a poor survival rate and procedural problems.

Currently, the USEPA does not have a cancer classification or a cancer slope factor for TCE. IARC has classified TCE as "Not Classifiable as to Human Carcinogenicity". The National Institute for Occupational Safety and Health (NIOSH) recommends that TCE be treated as a potential human carcinogen via inhalation.

Health effects through dermal exposure cannot be estimated from the available information.

Vinyl chloride

Vinyl chloride was detected in residential and groundwater monitoring wells and unremediated on-site soils. The levels in groundwater (both residential and monitoring) exceeded ATSDR's EMEG for both children and adults. The liver is the primary target of this chemical. The EMEG is based on the intermediate MRL for vinyl chloride which is in turn based on the lowest-observed-adverse-effect-level of 0.018 mg/kg/day which caused an increase in certain types of cellular nuclei. At slightly higher doses, animals have been shown to experience increased blood coagulation and an increase in skin collagen.

Vinyl chloride is classified as a human carcinogen by USEPA and IARC. Long-term cancer studies have shown vinyl chloride to cause liver tumors in experimental rats and mice. The MCL of 2 ppb has not been exceeded in residential wells, but has been exceeded in monitoring wells.

Health effects through dermal exposure cannot be estimated from the available information.

2. Other Organic Compounds

Benzene

Benzene was detected in groundwater monitoring wells and unremediated on-site soils. The highest values found in the soils and groundwater exceeded the respective CREGs. Benzene levels in residential wells did not exceed health guidelines. Long-term exposure to benzene can disrupt normal blood production and cause a decrease in important blood components. Benzene is a known human carcinogen. Leukemia is associated with long-term benzene exposure. Even if residential wells become contaminated with benzene at current monitoring well levels, lifetime consumption of the water would result in no apparent increased cancer risk from benzene exposure.

Ethylbenzene

Ethylbenzene was detected in on-site soil samples and in on- and off-site monitoring wells during the 1993 CSSI sampling. However, ethylbenzene has not been detected in any of the residential wells. No reliable data could be found concerning the effects in humans after eating, drinking, or breathing ethylbenzene or following direct exposure to the skin. The health effects of long-term exposure of animals to water containing specific levels of ethylbenzene are not known. USEPA's Office of Drinking Water (ODW) recommends 680 ppb as the acceptable exposure concentration of ethylbenzene in drinking water for an average weight adult. This value is for lifetime exposure and is not expected to increase the chance of experiencing (noncancer) health effects. No MRL has been established for this chemical.

bis-(2-ethylhexyl)phthalate and di-n-butylphthalate

Bis-(2-ethylhexyl)phthalate (DEHP) and di-n-butylphthalate were detected in unremediated and remediated on-site soils and groundwater monitoring wells. The concentrations of bis-(2-ethylhexyl)phthalate exceeded the CREG values in both media. In 1981, bis-(2-ethylhexyl)phthalate was also found in residential wells exceeding the CREG values. Recent residential well samples did not detect DEHP. The concentration of di-n-butylphthalate was above the pica child RMEG comparison value in the unremediated (1984) on-site soil samples, but was below all comparison values in the remediated (1987) on-site soil samples and in the groundwater monitoring well samples.

These phthalate esters are commonly found in the environment, and are the two most abundantly produced plasticizers. They generally have a low acute toxicity. Very limited evidence of adverse health effects in humans exists, but animal data show effects on the liver, testes, kidneys, thyroid, and pancreas as well as some effects on the development of the fetus.

Bis-(2-ethylhexyl)phthalate has been recently shown to cause liver cancer in rats and mice. The USEPA considers DEHP as a probable human carcinogen. Because DEHP appears to affect rats and mice differently than humans and other animals it is, however, difficult to predict health effects in humans from animal studies. Its carcinogenic mechanism has not adequately been demonstrated.

2-hexanone

2-Hexanone was detected in groundwater monitoring wells, but not in on-site soils or residential wells. No health comparison values have been established for 2-hexanone. The principal health effect associated with 2-hexanone exposure in animals and humans is neuropathy, generally accompanied by changes in body weight. Peripheral neuropathy has been associated with occupational exposure. Although the data are scant respective to hematological effects, there is evidence to indicate that the substance greatly enhances the hepatotoxicity of other chemicals. Based on animal studies, immunological, reproductive, and neonatal development effects may be of potential concern for humans under chronic exposure to 2-hexanone. In the male, semen production and fertility may be of concern. No animal or human data on genotoxicity or carcinogenicity exist.

2-butanone (MEK)

This contaminant was detected in on-site soils and in both on- and off-site monitoring wells during the 1993 CSSI sampling. However, it was not detected in residential wells. 2-Butanone can be absorbed after inhalation, ingestion, or dermal contact. There is no MRL, RfD, or cancer slope factor for this compound. It can cause irritation of the eyes and nose, dizziness, headaches, and vomiting; however, these symptoms may or may not occur at the concentrations found on-site. Very little information is available on health in people or animals following exposure to 2-butanone.

2-methylphenol (o-Cresol)

During the 1993 CSSI sampling, this contaminant was found in one on-site soil sample. None has been detected in off-site soils or in residential or monitoring wells. Studies in animals have described nervous effects, such as loss of coordination and twitching of muscles, that are produced by low levels of cresol. It is not known whether low levels cause such effects in humans, or whether cresols cause birth defects, affect reproduction, or cause cancer in humans.

Toluene

The 1993 CSSI sampling detected toluene in on-site soils and in both on- and off-site monitoring wells. Toluene has not, however, been detected in residential wells. There are limited animal data on the effects of oral exposure to toluene. No studies were located regarding reproductive, genetic, or carcinogenic effects in animals following oral exposure to toluene. Only one study was located regarding health effects in humans after oral exposure to toluene. This case study supplied limited data pertaining to effects other than death. Most studies involve the inhalation pathway. Exposure via inhalation to moderate levels of toluene has been associated with central nervous system depression. At lower exposure levels, subtle behavioral and neurological effects have been reported. Because of the amounts and locations of the contaminant on-site, such exposure is not likely.

Isophorone

Isophorone levels in unremediated on-site soils exceeded the CREG value as did the concentrations in groundwater monitoring wells. The levels in unremediated on-site soils exceeded ATSDR's intermediate (15-365 days) oral MRL for children but not for adults. The MRL has been derived from animal long-term exposure data for isophorone in food, which is 7 parts per million (ppm). The health effects which result from exposure to the chemical in water over the long-term (greater than 14 days) are not known. A harmful exposure to the chemical by breathing contaminated air is unlikely as it quickly dissipates. The only reported effects from human exposure to isophorone are eye, nose, and throat irritation, and fatigue and malaise. Possible synergistic interactions with other solvents can produce greater than additive toxicity. This has been demonstrated with tetrachloroethylene, propylene glycol, morpholine, ethyl alcohol, ethyl acetate, carbon tetrachloride, acrylonitrile, acetonitrile, and acetone.

Inconclusive studies with animals suggest that isophorone may have caused birth defects and growth retardation in the offspring of rats and mice that breathed the vapors during pregnancy. It is not know whether it causes birth defects in humans. A National Toxicology Program (NTP) study concluded that there is "some evidence of carcinogenicity" in male rats exposed orally to isophorone.

4-methyl-2-pentanone (methyl-isobutyl-ketone)

4-Methyl-2-pentanone was found in remediated on-site soils, and in groundwater monitoring wells both on- and off-site. It was not found in residential wells. Health comparison values for this compound are unavailable. The majority of the human toxicity data is workplace inhalation and dermal exposure, where the vapors are irritating to the skin, eyes, and nasal membranes. Gastrointestinal discomfort and central nervous system disturbances have also been noted from occupational inhalation exposures. 4-Methyl-2-pentanone is readily absorbed through intact skin.

The limited animal data available is insufficient to classify 4-methyl-2-pentanone as either a mutagen or carcinogen. It is not neurotoxic, but animal studies show that it can affect the kidney, liver, and cardiovascular system.

Naphthalene and 2-methylnaphthalene

Naphthalene has been detected in unremediated on-site soils. 2-Methylnaphthalene was detected at very low levels in remediated on-site soils between 7-12 feet deep along the southwest edge of the site. No health-based soil comparison values exist for these chemicals. Naphthalene and 2-methylnaphthalene belong to a group of chemicals called polycyclic aromatic hydrocarbons (PAHs) which will be discussed below. They do not rapidly volatilize and are considered semivolatile organic compounds (sVOCs). Naphthalene has been associated with hemolytic anemia, which is a disease which degrades the red blood cells. Ingestion has also been known to cause nausea, vomiting, and diarrhea. Cancer has not been seen in humans or animals exposed to naphthalene.

Xylene (total)

Xylene was detected in on- and off-site monitoring wells during the 1993 CSSI sampling. It was not detected in any of the residential wells. Xylenes can be absorbed after dermal contact, inhalation, or ingestion. There is no chronic oral MRL, RfD, or cancer slope factor for xylenes. Short-term exposure of humans to high levels of xylene can cause irritation of the skin, eyes, nose, and throat; difficulty in breathing; impaired function of the lungs; delayed response to a visual stimulus; impaired memory; stomach discomfort; and possible changes in the liver and kidneys. Both short- and long-term exposure to high concentrations of xylene can also cause a number of effects on the nervous system, such as headaches, lack of muscle coordination, dizziness, confusion, and changes in one's sense of balance. There is no present exposure to xylenes at this site because of the contaminant location and no exposure seems likely in the near future.

Polychlorinated Biphenyls (PCBs)

PCBs (Arochlor 1242, 1254, and 1260) have been detected in unremediated and remediated on-site soils. The highest value obtained greatly exceeded the ATSDR CREG, while other values were substantially lower. No PCBs were detected in residential or groundwater monitoring wells. PCBs are a group of chemicals which contain 209 individual compounds, known as congeners. The manufacture of PCBs was banned in l977 in the United States. Commercial mixtures of PCBs are generally known by their industrial trade name, Arochlor.

The health effects of these compounds are difficult to evaluate. As a group, PCBs are considered to be probable human carcinogens based on animal data. Insufficient data, relative to individual mixtures of PCB formulations, are presently available. Therefore, it is assumed that any composition of PCBs is potentially carcinogenic, but this assumption is presently unverified.

Hepatic, dermal, and ocular effects have been well established in occupational settings. Although reports of respiratory, gastrointestinal, hematological, muscular, and skeletal effects of exposure exist, the evidence is inconclusive. Occupational studies suggest increased incidence of liver and gastrointestinal cancer. In limited animal studies of dermal exposure, adverse hepatic, renal, dermal, immunological, and body weights effects were observed. The respiratory tract is a target in human inhalation exposures. Arochlor-induced gastric lesions occurred in monkeys, gastric ulcers occurred in mink and pigs, and intestinal metaplasia and adenocarcinomas occurred in the stomachs of rats following chronic oral exposure.

Polycyclic Aromatic Hydrocarbons (PAHs)

Benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, benzo((ghi)perylene, acenaphthene, indeno(1,2,3,-c,d)pyrene, chrysene, fluorene, pyrene, and phenanthrene belong to a group of chemicals called polycyclic aromatic hydrocarbons (PAHs). Some of the PAHs are thought to be carcinogenic.

All the PAHs listed above were detected in on-site soils. No health comparison values exist for these PAHs in soil. Benz(a)anthracene and chrysene were detected in residential wells. Proposed maximum contaminant levels (PMCLs) exist for benz(a)anthracene and chrysene in water. The concentration of these PAHS exceeded the PMCLs in residential wells by five and ten-fold. Benz(a)anthracene, benzo(b)fluoranthene, and benzo(k)fluoranthene were detected in an off-site monitoring well near the Acme facility in 1993. Benzo(b)fluoranthene and benzo(k)fluoranthene also have PMCLs. The concentration of these three PAHs exceeded the PMCLs by ten-fold or more.

The major target organ systems affected by PAHs are the hematopoietic and lymphoid systems in animals. The respiratory system may be a target system in noncancerous health effects. The PAHs have particular affinity for rapidly proliferating tissues. Evidence suggests that PAHs may contribute to atherosclerosis in humans. Although the evidence is slight, oral exposure may produce adverse gastrointestinal effects. Some evidence of hematopoietic toxicity in humans and animals exists. Dermal contact at high levels can cause skin problems. Some PAHs are immunotoxic.

Chronic exposure to several of the PAHs has caused cancer in animals, thought to result from biotransformation. Evidence suggests that cancers in humans arise in the lungs following inhalation and in the skin following dermal contact. Benz(a)anthracene may be carcinogenic through the oral route. Benz(a)anthracene, benzo(b)fluoranthene and chrysene have demonstrated tumorigenicity in rats and mice following dermal exposure. Benz(a)anthracene and chrysene have demonstrated mutagenicity. Benzo(a)anthracene, benzo(b)fluoranthene and chrysene may be genotoxic.

Vinyl Acetate

Vinyl acetate was detected in groundwater monitoring wells, but not in soils or residential wells. No health comparison values exist for vinyl acetate. Reduced body weight and retarded growth have been shown in some animals following inhalation and oral exposures. Acute human exposure can cause irritation of the nose and throat, but concentrations below 10 parts per million in prolonged occupational exposures produced no adverse respiratory effects in humans.

An increase in some tumors has been observed in rats after chronic inhalation or drinking water exposure. Vinyl acetate's mutagenicity has been demonstrated in vitro and the results suggest damage occurs at the chromosome level. Vinyl acetate is metabolized to acetaldehyde, which is an animal carcinogen. IARC considers vinyl acetate as not classifiable due to inadequate evidence or information available.

Dermal contact results in skin lesions and irritation in animals and humans. Although no adverse hepatic effects have been shown in humans, animal studies suggest that the liver may be a primary target organ.

Endrin

This pesticide was detected in two on-site soil samples during the 1993 CSSI sampling. It was not detected in any of the other on- or off-site media that were sampled. The use of endrin was strongly curtailed by the USEPA in the 1960s. In 1979, endrin was canceled for all but a few uses. Studies in animals indicate that endrin effects mainly the nervous system. Studies of workers exposed to endrin indicate such symptoms as headache, convulsions, dizziness, nervousness, and confusion. In studies of animals, endrin did not produce cancer. No increased incidence of cancers have been found in exposed factory workers. Only one soil sample had levels exceeding a screening health comparison value and that value was for chronic exposure to a pica child. Since this soil sample was found on-site and the site is restricted, chronic (long-term) exposure is highly unlikely.

Endosulfan

Endosulfan is a man-made insecticide and is also used as a wood preservative. It was detected in several on-site soil samples during the 1993 CSSI sampling. The chronic health effects on humans is not known. No information could be located on effects on human reproduction or birth defects. It is also not known if it causes cancer in humans. Results from animal studies show that exposure to very large amounts of endosulfan for short periods of time can cause adverse nervous system effects (such as hyperexcitability, tremors, and convulsions) and death. Also, harmful effects on the stomach, blood, liver, and heart were observed in animals exposed to high-levels of endosulfan. The kidney, testes, and possibly the liver are the only organs in laboratory animals affected by long-term exposure to low levels of endosulfan. Studies in animals have not shown evidence that endosulfan causes cancer in animals.

3. Inorganics

Arsenic

Arsenic was detected in groundwater monitoring wells at levels approximately three times the USEPA Rfd. No arsenic was detected in residential wells. There is mounting evidence from human and animal data that arsenic causes cancer by the oral route and is considered by USEPA to be a known human carcinogen by the inhalation route. Inhalation may produce lung cancer, respiratory irritation, nausea, and skin problems. The levels found were not above the MCL for arsenic in public water supplies. The USEPA has not calculated a cancer slope factor by which to estimate the increased risk from arsenic exposure.

In humans, oral exposure to levels of arsenic at least eight times higher than found in the monitoring wells is known to cause gastrointestinal irritation, nausea, vomiting, diarrhea, peripheral neuropathy, vascular lesions, anemia, and skin disorders, including skin cancer. Chronic oral exposure can cause circulatory problems, an extreme example being "Blackfoot disease" and gangrene. Hepatic changes, thought to be related to vascular effects have been shown from limited oral exposure data.

In animals, the data suggest that inorganic arsenic is a developmental toxicant, however, the fetus is not easily susceptible and doses required to produce toxic effects are toxic or fatal to the female mouse.

Lead

Lead is present in remediated and unremediated on-site soils. No health comparison values or minimum risk levels have been established for lead. Although lead is found naturally in soil, it is considered a no-threshold hazardous substance. Exposure to lead both orally and inhaled is considered detrimental to health, particularly to a fetus's or child's developing nervous system. It affects every organ and system in the body, but is most detrimental to the nervous, hematopoietic, and cardiovascular systems. Evidence suggests that the kidney and immune systems are also affected.

Nickel

Nickel was found as a contaminant in two of three on-site monitoring wells during the 1993 CSSI sampling. This element can be absorbed after ingestion, inhalation, and a small amount can be absorbed after dermal contact. Most ingested nickel is not absorbed, but is eliminated in the feces. After absorption, most nickel is transported to the kidneys and is eliminated in the urine. There is no MRL or cancer slope factor for this chemical. There is no information about cancer in people after oral exposure. Oral and dermal exposure to levels similar to those on-site can cause allergy. Sensitized individuals then exhibit skin dermatitis after being exposed to nickel.

Nitrate

Nitrate was detected in groundwater monitoring wells at levels slightly above the USEPA MCL for this compound. Nitrate has not been detected in residential wells. Children less than four months of age who are fed formula diluted with nitrate containing water are particularly susceptible to nitrate, which can cause symptomatic methemoglobinemia ("blue baby syndrome") at levels above the MCL. In severe cases, hypotension, shock, and cardiac arrhythmias may occur as well as instances of metabolic acidosis. Infants would be at particular risk should levels in residential well water reach those of the monitoring wells.

Zinc

Zinc was detected in groundwater monitoring wells at approximately three times the USEPA LTHA value. A secondary maximum contaminant level (SMCL) of 5 parts per million (ppm) has been established, based on taste considerations, which was slightly exceeded. No zinc contamination was found in residential wells. Zinc is a necessary nutrient for human health, and the Recommended Daily Allowance (RDA) is 15 milligrams per day for human males (0.21 mg/kg/day) and 12 milligrams per day for females. Levels above the RDA are necessary for pregnant and lactating females. Oral ingestion of zinc and zinc compounds has resulted in gastrointestinal and hematopoietic effects in humans and animals. Levels above the RDA can impair the immune and inflammatory response mechanisms. Data relative to adverse effects from dermal exposure is lacking. Very limited data exist regarding the development of cancer from zinc ingestion.

B. Health Outcome Data Evaluation

No state or local health outcome data have been reviewed for this health assessment. The population involved is too small for evaluation through state cancer, mortality, and adverse pregnancy outcome registries.

Members of the community around ACME are participating in ATSDR's TCE Exposure Registry and are being contacted at yearly intervals concerning their health status. Future health assessments that are prepared for the site will include an evaluation of available health outcome data as it becomes available.

C. Community Health Concerns Evaluation

Each of the community concerns have been addressed below.

Health problems associated with chronic exposure to contaminated groundwater:

Although it is not possible to say what health effects will occur as a result of the past exposure, the toxicological evaluation discusses the known effects based mainly on animal studies and some limited human health effects information. A number of the contaminants exceeded health guidelines and as a mixture are of public health concern for chronic exposure. A goal of the TCE Exposure Registry is to try and more accurately predict health effects from chronic, low-level exposures.

Concern about wells becoming contaminated without detection:

Until such time as the extent of groundwater contamination can be adequately defined, private wells in the vicinity of the study area should be evaluated for potential risk from site-related contamination. High risk wells should have the water tested at least quarterly to ensure early detection of plume migration.


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