PUBLIC HEALTH ASSESSMENT
CASSWOOD TREATED PRODUCTS
BEARDSTOWN, CASS COUNTY, ILLINOIS
In this section of the public health assessment, we describe environmental sampling previously conducted at the site and identify contaminants of concern found in specific environmental media. We evaluate the contaminants selected as being of concern and present our findings in subsequent sections of the public health assessment. We determine whether exposure to the selected contaminants has public health significance. The contaminants of concern are listed in the attached tables in Appendix B. We select contaminants of concern in an environmental medium by evaluating the following factors:
- Concentrations of contaminants.
- Data quality, both in the field and in the laboratory, and the sampling plan design.
- Comparison of contaminant concentrations and background concentrations with health assessment comparison values for both carcinogenic and noncarcinogenic end points (discussed further below).
- Community health concerns.
Comparison values used for a public health assessment are contaminant levels in specific environmental media used to select contaminants for further evaluation. These values include environmental media evaluation guides (EMEGs), reference dose media evaluation guides (RMEGs), cancer risk evaluation guides (CREGs), lifetime health advisories (LTHAs), and maximum contaminant levels (MCLs). If a site-related contaminant is found at levels above any of these comparison values or if no comparison value exists for the contaminant in a specific medium (air, water, or soil), the contaminant is referred to as a contaminant of concern and is evaluated for public health significance if people are exposed to the contaminant. Known or suspected human carcinogens with no carcinogenic comparison value are also listed as contaminants of concern and are evaluated further in this public health assessment.
EMEGs are comparison values developed from minimal risk levels (MRLs) for chemicals that are relatively toxic, frequently encountered at National Priorities List (NPL) sites, and present a potential health problem if people are exposed to the contaminant under certain conditions. EMEGs are derived as conservative comparison values that are protective of the most sensitive members of the population. EMEGs are chemical-specific values without consideration for carcinogenic effects, chemical interactions, multiple route exposures, or other media-specific exposures.
CREGs are estimated contaminant concentrations based on cancer slope factors (CSFs), which are estimates of one excess cancer in a million people exposed to a chemical over a lifetime (70 years). CREGs are also very conservative values designed to protect sensitive members of the population.
RMEGs are estimates based on reference doses (RfDs) of the daily oral or inhalation exposure dose to a particular chemical that is unlikely to produce any noncarcinogenic, adverse health effects over a lifetime of exposure. They are conservative values designed to protect sensitive members of the population.
LTHAs are estimated water contaminant concentrations an individual can drink for 70 years without experiencing noncarcinogenic, adverse health effects. These numbers contain a margin of safety to protect sensitive members of the population. These values are considered only if no EMEG, CREG, or RMEG is available as a comparison value for the contaminant.
The U.S. Environmental Protection Agency (EPA) established MCLs for public water supplies to reduce the chances of adverse health effects from use of contaminated drinking water. These standards are well below levels associated with health effects 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 considered only if no EMEG, CREG, RMEG, or LTHA is available for the chemical.
On August 6, 1986, site investigators performed a multi-method geophysical investigation to identify anomalous subsurface conditions and to define possible buried metallic objects at the site. One buried underground tank was found along the east property boundary. This underground fuel storage tank was removed on September 21, 1988 (AWE, 1990).
On-site wastes and potential contaminants were sampled in September 1988 to determine contaminant sources. Building wipe samples, tank samples, sump pit samples, and concrete slab samples were collected. Since all of these entities have been removed from the site, except for the concrete slabs, the results have not been included in this report. The concrete slab samples contained no contaminants above detection limits (AWE, 1990).
The laboratory results for air and soil data do not indicate the type of chromium found at the site. The type of chromium present is important because certain types of chromium may cause adverse health effects at different environmental levels if people are exposed to the chromium.
Numerous investigations have been conducted by various contractors and governmental agencies. A chronology of these investigations and other site actions are presented in the following discussion.
On June 30, 1986, Air, Water, Environment (AWE) performed an initial air quality survey with a photoionization detector. No readings were recorded above background levels. AWE collected three ambient air samples for heavy metal analysis in August 1986 (AWE, 1990). Lead and total chromium were present at levels above comparison values (Table 1). No comparison values exist for lead or chromium in air. The levels used for comparison purposes were obtained from the Agency for Toxic Substances and Disease Registry's (ATSDR) toxicological profile for each chemical. We found no other air monitoring data collected after 1987.
Site investigators defined surface soil as the soil collected from a depth less than or equal to 1 foot from the soil's surface. This differs from the ATSDR definition of surface soil as a depth of 0 to 1 inch, the depth that we feel people are most likely to touch or that is likely to become airborne. Of the samples collected, the Illinois Environmental Protection Agency took nine samples from the dirt floor of the treatment building. EP-toxicity tests were used for metals analyses. Most of the samples were collected in areas where chromated-copper-arsenate (CCA) product was observed on the soil floor. In 1986, Mathes collected 10 surface soil samples and analyzed the samples for dioxins. No dioxins were detected above the detection limits of the analyzing equipment. AWE collected the 1990 soil samples from the road surface that traverses the site. Samples were analyzed for metals only because pentachlorophenol (PCP), the organic contaminant of concern, is typically not present in surface soils because of its rapid photodegradation when exposed to ultraviolet light (AWE, 1990). The soil silt fraction and the less than 10 micron soil fractions were defined for the 1990 samples. These fractions represent the particle sizes that could potentially become airborne, disperse off site, and upon exposure, be absorbed by the human body.
In most of the investigation reports, the site is divided into different sampling areas. These areas are the lagoon area, treatment building area, seep area, and other on-site locales. The sampling location maps clearly display the areas. Figures 3 to 5 indicate the 1985 IEPA surface soil sampling locations, the 1986 Mathes sampling locations, the 1988/1989 Ott sampling locations, and the 1990 AWE sampling locations. Table 2 displays the contaminants of concern, their concentration ranges, and their comparison values.
On-site soil samples did not contain any organic contaminants above their detection limits. Heavy metals (arsenic, chromium, copper) were found at levels above either comparison values or background levels. These metals were found at the highest concentration in the silt and in the less than 10 micron fractions. Also, chromium VI was found in two samples collected by AWE in the less than 10 micron fraction. PCP (M/H, 1993) and two polycyclic aromatic hydrocarbons (PAHs) were also found above comparison and background values, although PCP is not likely to be found within the top 3 inches of the soil at appreciable levels.
Subsurface soil samples were collected from a depth greater than 1 foot. Sampling depths varied from 1.2 feet to more than 10 feet. Figures 3 and 4 depict most of the subsurface sampling areas. Table 3 lists the on-site subsurface soil contaminants, their concentration ranges, and their comparison values. The same contaminants of concern, including the same PAHs, were found in subsurface soils as were found in surface soils.
On-site monitoring well water was collected and analyzed. Approximately 8 on-site monitoring wells have been installed since 1988, and approximately 20 samples have been collected from those wells. Figure 5 shows the monitoring well locations. Monitoring well water contained chromium VI, PCP, dibenzofuran, fluoranthene, and pyrene at levels exceeding comparison values (Table 4).
We do not have data for off-site air. Airborne particulates may be deposited on neighboring properties and may be inhaled and ingested by people on adjacent property.
Approximately 50 off-site soil samples have been collected since 1987. Some were collected for background purposes, and others were collected to monitor or detect migration of contaminants off-site. Ott collected the 1987 soil samples to define background soil conditions. Ott collected two samples from the surface soil and two samples from subsurface soils. Figure 5 indicates the locations where background samples (BL-1 and BL-2) were collected. Sample location BL-3 was from an excavation designed to aid visual characterization of the soil. In 1988, Ott collected samples from the well auger borings drilled during installation of their eight monitoring wells. Figure 5 shows the locations of off-site wells (OW-1,7,8) where soil samples were collected.
In 1990, AWE collected five off-site soil samples for background information. Sample analyses results were used to refine the risk assessment model for dispersion of contaminated soil particulates through air emissions from the site. One composite soil sample (R-6) was collected from the yard of the site's nearest downwind residence. Sample R-7 was collected from the back lot of the Mascoutan Motel (Figure 6). These off-site soil samples were analyzed for the silt fraction and for the fraction equal to or less than 10 microns in diameter. No test was run to determine the presence of PCP. Sample R-4 contained the highest copper levels in all fractions, but all of the background samples contained copper in the less than 10 micron fraction at levels well above the Illinois maximum background soil concentration (IEPA, 1994). The highest arsenic and chromium concentrations were also found in sample R-4. Soil sample B-1 (Figure 7) was collected far north of the property as was another background sample. The smaller fractions were not analyzed in this sample, but tests for PCP were performed. The PCP concentration was well below the comparison value (AWE, 1990). In 1994, McLaren/Hart Environmental Engineering Corporation (M/H) collected 12 soil samples. M/H collected the samples from the former Pennington Crossarms property west of the site (Figure 8) (M/H, 1995). Those data are included in Tables 5 and 6.
Approximately 20 surface soil samples have been collected since 1987. Arsenic, chromium (total), copper, and PCP were the only contaminants detected above the comparison values or the Illinois maximum background soil concentration (Table 5).
The off-site subsurface soil samples contained the following contaminants at levels above comparison values or national maximum background soil concentrations: arsenic, PCP, phenanthrene, and chrysene. Table 6 lists the contaminants, their concentrations and ranges, and comparison values.
Groundwater samples were collected and analyzed from numerous off-site monitoring wells, a few private wells, and one municipal well.
Approximately 31 monitoring wells have been installed off-site to monitor groundwater contaminant levels and to determine the contaminant migration direction. In 1988, different companies began installing the wells. Figure 5 shows the Ott well locations. Figures 6 and 7 show the Woodward-Clyde Consultants (WCC) and M/H monitoring well locations. Figure 9 shows all the monitoring wells in the area, including Bohn Aluminum's monitoring wells. In 1994, M/H sampled the four extraction or recovery wells along Kent Feed Road, which is northwest of the site. Those samples were collected to help assess the area's groundwater quality and the recovery system's efficiency. Numerous contaminants were found in the water samples at levels above their comparison values. Table 7 lists the contaminants, their ranges and frequencies, and their comparison values.
Only three private wells were sampled in conjunction with this site. The wells are on the former Oscar Mayer Company property (now EXCEL). These wells are not in the direction of the groundwater flow. IEPA collected those samples on September 8, 1986. No contaminants were found at levels above the detection limits. An Illinois State Water Survey representative states that numerous private residential wells are located in the surrounding area and should be sampled. One private well is downgradient of the site, but we do not know whether the well is used. IEPA sampled the well on April 26, 1989, but the data report is not available. No other residential or commercial wells were found in the path of the groundwater flow from the site.
Only one municipal well (#4) was sampled in conjunction with the Casswood site investigations. WCC collected the sample in 1990. The sample was tested for PCP and heavy metals, and no contaminants were present at levels above comparison values. IEPA monitors public water supplies regularly. IEPA monitoring includes analyses for volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) every 3 months and analyses for inorganic compounds every 3 years. All of the site contaminants of concern, except dibenzofuran and copper, are included in IEPA's standard analyses. We reviewed the last 5 years of IEPA data for the Beardstown municipal water supply and did not find the presence of any contaminants at levels above comparison values. The water treatment plant in operation at the Casswood site is designed to capture all constituents of the contaminant plume (inorganic compounds, VOCs, and SVOCs) before they reach the municipal wells. The monitoring well data show that SVOCs (such as dibenzofuran) have migrated no further than approximately 200 feet off site and that inorganic compounds (such as copper) migrate at an even slower pace.
4. Surface Water
In 1990, the only known surface water sample was collected and analyzed for PCP and heavy metals. No contaminants were detected above their detection limits. This sample was collected from the ditch in the vicinity of the monitoring well OW-24 (Figure 10).
5. Separate Phase Hydrocarbons or Nonaqueous Phase Liquids
Two separate sampling events were performed to develop an understanding of floating, separate phase hydrocarbons (also called nonaqueous phase liquids) on the water table, of their recoverability, and of their chemical concentrations. On April 30, 1989, a composite oil sample was collected from monitoring wells OW-8 and OW-16 and submitted for PAH and PCP analyses. On April 3, 1992, hydrocarbon samples were taken from monitoring wells OW-6 and OW-8. The samples were analyzed for VOCs, SVOCs, cyanide, metals, polychlorinated biphenyl (PCB)/pesticides, and dioxins/furans. Table 8 lists the contaminants, their concentrations, and their comparison values. Drinking water comparison values were used for evaluation purposes even though the uppermost layer of the water table will not likely be drawn into the well pump and distributed as drinking water.
6. Toxic Chemical Release Inventory
Industries must report their air, water, and land emissions to EPA. EPA established a reportable quantity for each of these compounds in emissions. This information is available through a database, the Toxic Chemical Release Inventory (TRI). For TRI data from 1992 to 1994, only one industry in Beardstown (ZIP Code 62618) released reportable quantities of toxic substances to the environment (Table 9).
The numerous investigation reports included quality assurance/quality control (QA/QC) data. Sample handlers followed acceptable QA/QC procedures for chain of custody, blanks, and laboratory procedures. Specific procedures were applied to all phases of analysis, from sample receipt through the final reporting of results. Also, data were evaluated and monitored for appropriateness of analytical processes for ensuring that the quality control systems were performing effectively. EPA-approved methods were used for laboratory analyses.
In the Mathes investigation (1986), a significant number of analyses failed to meet quality control measures. Analyses for metals failed approximately 52 times. Ninety-three samples were collected and were analyzed for five metals, PCP, and PAHs. No reason was given for the failed analyses. Also, various detection limits were used during the numerous investigations. A few detection limits, especially those discussed in the older reports, were greater than the comparison values. Therefore, some contaminants may have been undetected or have been present at levels above the comparison values.
Overall, the Illinois Department of Public Health (IDPH) relied on the information provided in the investigation documents. IDPH assumed that adequate QA/QC measures were followed regarding chain-of-custody, laboratory procedures, and data reporting. The analyses, conclusions, and recommendations in this public health assessment are valid only if the referenced documents are complete and reliable.
The physical hazards on the site include the two Browning Ferris Industries dumpsters in the lagoon area, a large tank that has two holes which provide access inside the tank, remaining barrels, and general debris. As we noted on site visits, trespassers use the site frequently.
To determine whether nearby residents are exposed to contaminants migrating from the site, the Illinois Department of Public Health (IDPH) evaluates the environmental and human components that lead to human exposure. A hazardous chemical can affect people only if they come in contact with the contaminant at sufficient concentrations and for a long enough period to cause a toxic effect. For an exposure to occur, a source of contamination, an environmental transport medium, a route of exposure, and an exposed population must all be present. An exposure pathway is complete if all these components were present in the past, are currently present, or will be present in the future. If any component of an exposure pathway is absent, then we classify the exposure pathway as potential if past, present, or future exposure is possible. If any exposure pathway component is missing and will never be present, then we eliminate the exposure pathway from further evaluation.
On-site workers and trespassers are assumed to be exposed to contaminants in on-site surface soil. People are exposed by dermal contact, incidental ingestion, or inhalation of contaminants in soil and dust. Because site access is not restricted, people have been, are, and will continue to be exposed to surface soil contaminants until site access is restricted or surface soils are remediated. On-site workers can reduce their exposure by using personal protective equipment.
Elevated levels of arsenic, pentachlorophenol (PCP), and two polycyclic aromatic hydrocarbons (PAHs) were found in one residential yard sample and in a sample taken from the yard of a motel. Residents and people working and staying at the motel are assumed to have some contact with the contaminants found in the soils of these yards. As with persons on the site, those people touching the soil, ingesting the soil, or inhaling dust particles are exposed to the contaminants. The levels of PCP found within the top 3 inches of soil are expected to be much lower than the levels found in the 0 to 1 foot samples because of rapid photodegradation and oxidation of PCP when it is exposed to sunlight. Samples taken at greater distances from the site contained lower levels of contaminants and do not likely pose a significant risk of exposure.
For the Casswood site, people are more likely to be exposed to contaminated, airborne particulates than to volatile organic compounds. Those exposures were previously discussed. Some lighter components of PAHs are more volatile than others and may be released if the site is excavated. Remedial workers can minimize their risk of exposure by using personal protective equipment.
Groundwater at the site is contaminated, and some contamination may have migrated from the site before the recovery well system was installed. One downgradient private well has been identified and sampled, but we could not find the data for that well. We are unsure whether the well is being used. The municipal well field is downgradient of the site, but no contaminants have been found in any of the wells to date. The Illinois Environmental Protection Agency (IEPA) monitors the system routinely. No contamination is expected to reach the municipal wells as long as the site recovery well system is working. However, we are not sure that all private wells in the area have been identified and tested.
3. Surface Water
The one off-site surface water sample analyzed did not contain contaminants, but more surface water samples should be tested to determine if site-related contaminants have reached Hard Road Park pond, which is used for recreational fishing. If contaminants have reached the pond, people could contact contaminants in the water through wading and through some incidental ingestion.
People are not likely to be exposed to contaminated food products. However, some people in the area do have gardens. Legumes, such as soy beans, can take up arsenic in edible portions of the plants, although soil conditions play an important role in how much arsenic is absorbed by the plants. Washing plants before eating them should eliminate ingesting any contaminants present in soil on the plants. Some metals may accumulate in fish, too. However, we have no data to indicate that fish in the area are contaminated.
To evaluate potential health effects, the estimated exposure doses to site-related compounds were compared with health effects information in the literature, primarily to the Agency for Toxic Substances and Disease Registry's (ATSDR) toxicological profiles. These chemical-specific profiles provide information on health effects, environmental transport, human exposure, and regulatory status. ATSDR and the U.S. Environmental Protection Agency (EPA) have developed chemical-specific guidelines for evaluating the potential for adverse health effects of chemicals in air, water, and soil. ATSDR has developed minimal risk levels (MRLs) to evaluate noncancerous health effects. An MRL is an estimate of the daily human exposure to a contaminant below which noncancerous adverse health effects are unlikely to occur. MRLs are developed for both the oral and inhalation routes of exposure. They are also developed for different lengths of exposure, such as acute (14 days or less), intermediate (15 to 365 days), and chronic (more than 365 days). An EPA reference dose (RfD) is an estimate of the daily exposure to the general public that is likely to be without an appreciable risk of deleterious noncancerous effects during a lifetime. EPA has also developed health advisories for exposure to drinking water for periods of 1-day, 10-day, longer-term, and lifetime exposures to noncarcinogens.
EPA also evaluates the potential of a chemical to cause carcinogenic effects over a lifetime. The agency has estimated cancer slope factors for certain chemicals with sufficient toxicological information on cancerous effects. These cancer slope factors are estimates of the potency of a chemical to cause cancer and are used to estimate the cancer risk of specific doses. These cancer risk estimates are very conservative and are meant to protect susceptible members of the population.
EPA has established a classification system for carcinogens based on the adequacy and consistency of the available human and animal data. Group A compounds are known human carcinogens. Group B1 compounds are probable human carcinogens based on limited human data. Group B2 compounds are probable human carcinogens based on sufficient evidence in animals, but inadequate or no evidence in humans. Group C compounds are possible human carcinogens based on limited data. Group D compounds are not classifiable as to human carcinogenicity because of inadequate or no data. For Group E compounds, evidence exists that they do not cause cancer.
The following were used for exposure estimate calculations: For drinking water consumption, 1 liter per day for children and 2 liters per day for adults; for soil ingestion rates, 200 milligrams per day for children and 100 milligrams per day for adults; and for body weight, 10 kilograms for children and 70 kilograms for adults.
1. Organic Chemicals
Pentachlorophenol (PCP) is a chemical of concern that was found in on- and off-site surface and subsurface soil and in on- and off-site groundwater monitoring wells. EPA has classified PCP as a B2 carcinogen. Short exposures to large amounts of PCP can cause harmful effects on the liver, kidneys, skin, blood, lungs, nervous system, immune system, and gastrointestinal tract. PCP can cause death in humans if large amounts enter the body. The lengths of exposure and the levels that cause harmful effects have not been well defined. Studies in animals have shown that long-term, low-level exposure to PCP can affect the liver, kidney, nervous system, and the immune system (ATSDR, 1992a).
Oral or dermal exposure to PCP found in surface soils on- or off-site would not be a concern for cancerous or noncancerous effects. Lifetime consumption of groundwater with the maximum detected PCP concentration found in the on- and off-site monitoring wells would result in a very high to high increased cancer risk. Also, noncancerous health effects could be possible if people were exposed to PCP at this concentration over a lifetime. Fortunately, the groundwater treatment system is actively treating the groundwater to help prevent these high levels of PCP from entering private and public wells. Also, the absorption of PCP onto the organic carbon component of soils will retard the migration of PCP in the groundwater. This has been observed at Casswood (AWE, 1990). Public water supplies are required to be monitored, but private wells are not. Whether PCP is present in some nearby private water wells is not known.
b. Polycyclic Aromatic Hydrocarbons (PAHs)
PAHs (common combustion products) were found in on-site surface and subsurface soils, off-site subsurface soil, and on- and off-site groundwater. PAHs can be absorbed after inhalation, ingestion, or dermal contact. Many of the PAHs are classified as probable human carcinogens (Group B2) by EPA. PAHs are present naturally in the environment. PAHs in general do not easily dissolve in water. Most stick to solid particles and settle to the bottoms of rivers and lakes. PAHs are not stored in the body for long periods; most PAHs that enter the body are excreted within a few days through urine and feces. PAHs can cause harmful effects to the skin, body fluids, and the body's system for fighting disease after both short- and long-term exposures (ATSDR, 1992b).
The main routes of exposure to PAHs on and off the site are inhalation of PAH-contaminated dust, ingestion of contaminated water, and skin contact with contaminated dust or water. Trespassers and area industrial workers would be the most likely people to be exposed to the PAH-contaminated dust, which can be easily stirred up by vehicular traffic.
EPA has developed a cancer slope factor for benzo(a)pyrene (BaP), as well as relative potency factors for the other carcinogenic PAHs. We used these numbers to calculate an estimate of the cancer risk as a result of lifetime consumption of on-site and off-site surface and subsurface soil. Consumption of the highest concentration of PAHs found on the site would not result in an apparent increased risk of developing cancer. If subsurface soil was exposed and people consumed levels found in the subsurface soil, the estimated risk would increase slightly; however, that scenario is unlikely to occur. The PAHs found in the soil were phenanthrene and chrysene. The cancer slope factor used for the calculations was based on the BaP cancer slope factor. BaP is one of the most potent PAHs. Phenanthrene and chrysene's estimated relative carcinogenic potency is low to marginal when compared with that of BaP. Noncancerous health effects are not expected to occur with daily ingestion or inhalation of PAH-contaminated soils.
PAH levels found in monitoring well water could pose a significant cancer risk if those levels ever reached a drinking water supply and people drank the water daily for a long period. The recovery well system should prevent future migration of PAHs from the site, and municipal water supplies are periodically monitored for contamination. We do not have data to evaluate the safety of all private drinking water wells in the area; however, only one private well has been identified as downgradient of the site. The well has been sampled, but the data was not available.
Dibenzofuran was found only in the groundwater at levels above comparison values. Dibenzofurans are a family of chemicals known as chlorinated dibenzofurans. This family contains 135 individual compounds (congeners) with varying harmful health and environmental effects. EPA classifies dibenzofurans as possible human carcinogens. Large doses have caused adverse health effects (ATSDR, 1991b). Individuals exposed orally to the maximum dibenzofuran level found in the groundwater for a lifetime could experience adverse health effects. Dibenzofurans have not been detected in the public water well supply. Private water supplies have not been sampled for dibenzofurans.
Di-n-butylphthalate was detected in one sample collected in 1988 from a groundwater monitoring well. This synthetic chemical is used mostly to help make plastics soft and flexible. People exposed to di-n-butylphthalate have not reported any adverse health effects. Animals that ingested large amounts of di-n-butylphthalate have had their ability to reproduce affected. There is no evidence that di-n-butylphthalate causes cancer, but this has not been thoroughly studied (ATSDR, 1989b). The level found in the monitoring well may cause adverse health effects to individuals if they ingested the contaminated water daily over a lifetime. We do not know if any private wells in the area contain di-n-butylphthalate.
2. Inorganic Chemicals
Arsenic was found in the soil (on- and off-site surface and subsurface) and in groundwater. Arsenic can be absorbed after inhalation or ingestion. While large amounts are harmful, small quantities of arsenic may be beneficial. Inhalation of arsenic increases the risk of lung cancer, and oral exposure of arsenic has been linked to increased incidences of skin cancer (ATSDR, 1991a). EPA has classified arsenic as a known human carcinogen (Group A). EPA developed a cancer slope factor for arsenic that can be used to estimate the risk of cancer from ingestion or inhalation of specific doses. Lifetime inhalation and ingestion exposure to the maximum arsenic level found in the on-site surface soils would present a low increased risk of cancer to those exposed. Exposure would most likely be to trespassers and to persons driving through the site. Therefore, the actual exposure would be less since those accessing the site would not be continous contact for a lifetime. The risk of noncancer health effects is high because of the levels found, but consistent exposure would not realistically take place. If inhaled or ingested, off-site surface soils containing arsenic would present a low increased cancer risk to children. The noncancer risk also is a concern for small children exposed to these levels of arsenic. Further sampling is necessary to verify actual exposure potential.
Exposure to groundwater over a lifetime with the maximum level of arsenic found would pose a low increased risk of cancer for adults and a moderate risk of cancer for small children. Since the public water wells are tested routinely, exposure by this route is unlikely. Private water supplies, however, may be a concern.
Total chromium was detected at levels of concern in the on-site surface and subsurface soils and in off-site surface soil. Chromium VI was found in the groundwater monitoring wells at levels exceeding comparison values. Chromium is present in the environment in several different forms, and these different forms can affect the body in different ways. Long-term exposure to high levels of chromium has been associated with lung cancer. EPA lists chromium as a Group A carcinogen (ATSDR, 1991c). However, exposure to the contaminated soil either on or off the site by inhalation or ingestion would create no apparent increased risk of cancer. The risk of noncancerous health effects is not increased for inhalation or ingestion of chromium-contaminated soil at the maximum level found. Since specific chromium types were not analyzed, further sampling could be more characteristic by delineating the type of chromium found. Exposure to the chromium-contaminated groundwater would not be expected to cause any adverse health effects.
Copper was found in the soil (except in the off-site subsurface soil) at levels above the maximum Illinois background soil concentration (IEPA, 1994). Copper is very common in the environment. It is necessary for good health; however, very large single or daily intakes of copper can harm your health. Copper is not known to cause cancer and is not classified as a carcinogen. No health guidelines were found to compare with environmental levels; therefore, they are compared with background levels. Exposure would be through ingestion or inhalation of contaminated dirt or dust by those trespassing or working at the site. The copper levels found would not be expected to cause adverse health effects (ATSDR, 1989a).
The Illinois Department of Public Health did not find any site-specific health outcome data that would be helpful in evaluating exposures at the site. No health studies have been performed on people around the Casswood site. We found no evidence that people have been exposed to hazardous chemicals at the site at doses that could result in adverse health effects. Although we assume that trespassers and workers in the area have been exposed to site contaminants, we believe their exposure would not result in a dose that would result in adverse health effects.
One citizen concern is the possible future contamination of municipal and private wells. The Beardstown municipal well field is approximately 1,000 feet north of the site and groundwater flows in that general direction, as does the contaminant plume. The municipal wells should not be contaminated by the site because of the groundwater treatment system that was installed. Routine monitoring of the municipal water supply also aids in detecting any contamination before the water is distributed for use. We do not know enough about private wells in the area at this time to evaluate potential exposures through use of private well water. Therefore, people who are using a private well supply that is downgradient, (within one-half mile of the site), should notify us of the well location so that steps can be taken to have the well tested.
Another citizen concern is the ease of accessibility of the site and the potential hazards that it presents to those trespassing. This is a valid concern because trespassers are exposed to on-site soil contamination, and injuries could occur from the physical hazards that are present.
We know of two other concerns pertaining to this site. One concern was about the economic issues of converting the site and surrounding area into a useful development. The other concern pertained to the potential installation of a municipal waste incinerator in the area of the Casswood site. The incinerator proposal has since failed.