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The tables for this section list the contaminants that exceed comparison values (Appendix B). These contaminants are evaluated further in the remaining sections of this public health assessment to decide if they pose a threat to public health. The listing of a contaminant in the 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. Concentration of contaminants in all media;
  2. Data quality in the field and laboratory and design of sampling plan;
  3. Comparison of contaminant concentrations and background concentrations with environmental media comparison values for both carcinogenic and noncarcinogenic endpoints; and
  4. Community health concerns.

Comparison values are used to select contaminants for further evaluation. These values 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 greater than 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 public health assessment to decide 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 for further investigation and will be evaluated in the remaining sections of this public health assessment.

EMEGs are comparison values developed for chemicals that are 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). They do not consider carcinogenic effects, chemical interactions, multiple route exposures, or other media-specific values designed to protect the public.

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

RMEGs are comparison values based on USEPA's Reference Doses (RfDs) or Reference Concentrations (RfCs). These values are estimates of a daily oral or inhalation exposure to a particular chemical that is unlikely to cause any noncarcinogenic adverse health effects. These numbers may be adjusted to protect sensitive members of the population.

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

USEPA has established MCLs for public water supplies to reduce the chances of adverse health effects from ingesting contaminated drinking water. Secondary MCLs (SMCLs) are set for aesthetic purposes, such as the taste or color of drinking water. These standards are much lower than levels for which health effects have been observed and take into account the financial feasibility of achieving specific contaminant levels. MCLs and SMCLs are enforceable limits that public water supplies must attain. These values are considered if no EMEG, CREG, RMEG, or LTHA values are available for a chemical.

The following section characterizes the waste constituents present, based on data available to IDPH, on or near the H.O.D. Landfill.

A. On-site Contamination


Testing Service Corporation (TSC) conducted a soil investigation in 1973, in which they constructed 25 borings and installed 6 groundwater monitoring wells (WMI wells) at H.O.D. The inorganic analysis of the groundwater was summarized in a "Trends Analysis Report" prepared by IEPA for samples collected between November 1974 and December 1981 from six on-site monitoring wells (Ecology and Environment, 1989). References about consistently high concentrations of iron, residue on evaporation, and zinc were allegedly in the report; however, the report was not found, and this cannot be confirmed. In 1981, TSC drilled 26 soil borings at the site, and a hydrogeological report was completed in response to the proposed northern expansion of the landfill.

USEPA requested that a Preliminary Assessment be done by Ecology and Environment's Field Inspection Team. The report was completed on February 11, 1983, and data gaps were identified that included the actual waste quantities and groundwater and surface water contamination (Ecology and Environment, 1989). Because of these identified data gaps, USEPA requested a site investigation, which was completed on July 10, 1984. Groundwater samples were taken which revealed the presence of elevated concentrations of zinc, lead, and cadmium. High zinc levels were attributed, by WMI, to a deteriorating galvanized pipe in monitoring well G103. The well was subsequently replaced with well R103 on October 31, 1985.

The Dames and Moore hydrogeological report (Ecology and Environment, 1989) summarized and compared the results of inorganic analyses for chloride, zinc, and total dissolved solids. The data were from three samples: a water sample from municipal well number 4 collected on April 19, 1982; a sample from monitoring well G103 collected on April 9, 1984; and a leachate sample from the landfill collected on April 9, 1984. The groundwater and municipal water samples contained no significant contamination. However, organic analyses of the leachate reportedly revealed the presence of low levels of methylene chloride, benzene, toluene, trans-1,2-dichloroethylene, 1,2-dichloropropane, and ethyl benzene. As this report was not found, this cannot be confirmed.

Subsequently, groundwater samples were collected by Ecology and Environment's Field Investigation Team in three sampling rounds: Round 1 (August 10-12, 1987); Round 2 (April 18-19, 1987); and Round 3 (May 19, 1988). Round 1 samples were collected from 15 monitoring wells and 8 drinking water wells (7 residential wells and municipal well number 4). The Round 2 samples were taken from 10 monitoring wells. Volatile organic compounds (VOCs) were the only contaminants measured in this round of sampling. The Round 3 samples were collected from five monitoring wells and were also analyzed for VOCs. Figure 5 shows the locations of the groundwater (and soil) sampling.

WMI collected groundwater samples from 10 of the monitoring wells on July 25 and 26, 1990. They were analyzed for selected organics, metals, and groundwater indicator parameters (Warzyn, 1992). The company also supplied IDPH with a data compilation of five on-site groundwater monitoring wells (G11D, G11S, G14D, R103, and G102). Figure 4 shows the location of the groundwater monitoring wells.

Table 1 lists the contaminants found in the on-site groundwater monitoring wells since 1985 at levels greater than comparison values. It also includes data from a groundwater hydropunch sample taken on May 4, 1990, 10 feet north of well S4S, at approximately 20 feet below the ground surface. The frequencies of detection given in Table 1 vary per chemical as do the numbers of samples collected and reported, due to incomplete data profiles, dry wells, and variability in analytical reporting.


Leachate, collected on April 9, 1984, in association with the 1985 Dames and Moore report, was analyzed. On June 28, 1990, leachate samples were taken from the "new" landfill and analyzed for organics. Samples were taken from temporary piezometers on the "old" landfill on July 27, 1990, and on August 10, 1990. These samples were analyzed for organics, metals, and groundwater quality indicator parameters. Table 2 lists the components of the H.O.D. leachate. The values in Table 2 are not represented by frequencies of detection or numbers of samples. Comparison values are not appropriate for selecting contaminants in leachate because leachate is a concentrated source of contaminants and the public is not expected to have direct contact with it.

Subsurface Soils

Forty-nine subsurface soil boring samples were collected from May 26 to July 16, 1987, for analysis by Ecology and Environment. Thirteen samples were taken on-site. Sample depths varied from 22 to 71.5 feet among the soil borings. Background soil samples (not shown in Table 3) were collected off-site and upgradient of the site and were designated as S37, S38, S39, S40, (taken from soil boring GW5D) and S48 (taken from soil boring GW7S). Table 3 presents the contaminant levels that exceeded comparison values or for which no comparison values exist. Figure 5 shows the soil boring locations.

The background sample analyses are not included in Table 3. Of the organic compounds, di-n-butyl-phthalate was also detected in background samples at 450-1,100 parts per billion (ppb). Phthalates were also found in the laboratory blank. Neither chrysene, di-n-octyl-phthalate, nor 2-methylnaphthalene were detected in background samples.

With respect to inorganics, arsenic was detected in only one background sample at 15 ppm. Beryllium was detected in trace amounts (0.66-0.89 ppm) in four of five samples. Chromium, cobalt, copper, lead, manganese, and nickel were detected in all five background samples at levels similar to the on-site samples. Vanadium was present from 13-22 ppm in the background samples, but was detected at up to 65 ppm in the on-site samples. A data gap is identified in that soil samples were not taken closer to the surface than 22 feet.

B. Off-site Contamination


IDPH reviewed files in the Maywood IEPA office for the years 1970-1979 and found documentation that unspecified contamination was in one deep and one shallow aquifer. A sample taken on April 19, 1982, from municipal well number 4 contained no significant levels of inorganic contaminants. The well was also sampled by IEPA on September 1, 1982, and no VOCs were detected in the sample (Ecology and Environment, 1989). On January 9, 1986, IEPA collected groundwater samples from four residential wells that were east of the H.O.D. Landfill. The samples were analyzed for nitrates, organic compounds, and trace metals. No maximum allowable concentrations of trace metals were exceeded, and no organic compounds were detected.

Groundwater samples were collected in three sampling rounds: Round 1 (August 10-12, 1987); Round 2 (April 18-19, 1988); and Round 3 (May 19, 1988) (Ecology and Environment, 1989). Round 1 samples were collected from 15 monitoring wells and 8 drinking water wells (7 residential wells and municipal well number 4). The Round 2 samples were taken from 10 monitoring wells and were measured for VOCs only. The Round 3 samples were collected from five monitoring wells and analyzed for VOCs (Figure 5). Table 4 presents the off-site groundwater monitoring well contaminants that exceeded comparison values.

As additional state statutory requirements for public water supply monitoring became effective in 1989, IEPA has regularly monitored the Village of Antioch's public water supply wells for greater numbers of inorganic and organic contaminants than was previously the case. Data spanning the years 1982 through 1996 were provided to IDPH from IEPA's Public Water Supplies Division. Table 5 presents the contaminants detected above comparison values in the Village of Antioch's public water supply for the periods 1982 through 1996. The frequencies of detection given in Table 5 vary per chemical as do the numbers of samples collected and reported, due to an incomplete data set and variability in analytical reporting.

The public supply well closest to the site, municipal well number 4, contained arsenic, boron, lead, sodium, thallium, tetrachloroethylene, and vinyl chloride. However, because the contaminant levels were low and within the established MCLs for a public water supply, the well was not in violation of State drinking water regulatory standards. Also, most of the contaminants in the IEPA file data were reported from raw, versus finished water treated to remove contaminants. As previously discussed, comparison values given in this public health assessment, if exceeded, show which chemicals should be evaluated further, while MCLs are enforceable levels that public water supplies must meet for selected contaminants. MCLs are set below levels thought to be harmful to human health and consider the economic feasibility of treating water to reduce contamination to that level. Therefore, a chemical may exceed a comparison value, yet meet water quality regulatory standards and not pose a threat to human health, depending on the circumstances of the actual exposure.

Private Wells

Private well samples were collected from seven private drinking water wells on August 13, 1987, by Ecology and Environment (Figure 3). Routine residential well sampling undertaken by the Lake County Health Department historically showed the presence of excess iron and total dissolved solids, but these were attributed to natural causes and conditions in Lake County (Lake County Health Department, files). Table 6 lists the contaminants detected above comparison values in the sampled private wells.

Surface Water

Periodic surface water sampling of Sequoit Creek in the 1970s at H.O.D. Landfill by the Lake County Health Department showed the presence downstream of excess phosphorus, chloride, nitrate, zinc, iron, ammonia, sulfates, specific conductivity, total dissolved solids, chemical oxygen demand, boron, and hardness. Downstream increases in pH, chromium, copper, iron, lead, nickel and zinc were also noted (Lake County Health Department, files). However, IEPA records and the 1989 Ecology and Environment expanded site investigation suggested that no creek contamination had occurred (IEPA files, 1985). The lack of current surface water sampling data of Sequoit Creek and the wetlands represents a data gap.


Methane is generated by the site. High organic vapor analyzer readings at groundwater wells near the southern area of the "old" landfill (Wells US6S, US6D, R103, US4S, US4D, and G102) suggest methane is present in the soils at the site perimeter. The dates of the organic vapor analyzer sample collection and analyses are unknown. The gas is presently vented and flared. No other gas or air sampling data were found.

Subsurface Soils

Thirty-six off-site deep subsurface soil boring samples were collected from May 26 to July 16, 1987 (Ecology and Environment, 1989). Figure 5 shows the locations of the soil borings. Table 7 lists the contaminants detected above comparison values or those for which no comparison values exist for off-site subsurface soil samples.

Table 7 does not include background sample analyses that are discussed here. Of the off-site subsurface soil contaminants listed in Table 7, di-n-butylphthalate and bis(2-ethylhexyl) phthalate were also detected in background samples at 450-1,100 ppb and 180-730 ppb, respectively. The bis(2-ethylhexyl) phthalate values were estimated, and the compound was also detected in the laboratory blank. None of the other organic compounds detected in the off-site samples was present in the background samples. Of the inorganic compounds detected, all were detected in the background samples at similar concentrations to the off-site sample values listed in Table 7. No soil samples or wetlands and Sequoit Creek sediment samples, which represents a data gap, have been collected and analyzed.

Contaminants Selected for Further Evaluation

As previously stated, although selected chemicals may have been detected on-site and near the H.O.D. Landfill, they do not necessarily pose a threat to human health. Chemicals may be listed in tables that are not discussed in this section because the levels, although above comparison values, are not likely to cause adverse health effects or are not part of a human exposure pathway, such as contaminants in subsurface soil. If additional data are forthcoming, or if site conditions change, this public health assessment will be modified. A brief discussion follows about the contaminants whose levels show little increased risk of adverse health risks and are not considered contaminants that need further evaluation.

Arsenic was detected in the Village of Antioch's public water supply (at a peak concentration of 5 ppb), and in the private wells, groundwater monitoring wells, and subsurface soils. The Antioch municipal water supply currently meets water quality standards. The MCL for arsenic is 50 ppb, or 10 times the level detected. Arsenic levels of 5 ppb are not uncommon in public water systems, and health effects have not been reported for people who consume naturally occurring arsenic at that level.

Manganese was detected above comparison values in on- and off-site groundwater monitoring wells and subsurface soils. Manganese is an essential dietary component ingested in trace amounts. Because homeostasis regulates manganese uptake and elimination, wide dietary ranges are considered safe. However, newborn children may be at increased risk of toxicity because of higher gastrointestinal uptake. In adults, manganese is considered among the least toxic of the trace elements because 3 to 10% of the ingested manganese is generally absorbed through the diet. Epidemiologic studies of humans who have ingested manganese in drinking water encountered much higher exposures than those detected at H.O.D. The World Health Organization (WHO) concluded, from studies of adult diets, that up to 8-9 mg manganese/day is "perfectly safe." Given the low levels present in the monitoring wells and subsurface soils (which approximate typical soil values), IDPH does not expect the manganese in the groundwater to cause adverse health effects.

Sulfate was detected in on-site groundwater monitoring wells. Sulfates are a very common constituents of drinking and surface waters. Inhalation of high concentrations of sulfate ions, with other indoor air pollutants, has been implicated in altered upper airway function and irritation. A proposed MCL of 400,000 ppb for sulfate in water exists, which was exceeded twofold in the groundwater monitoring wells (ATSDR, 1994). Since on-site groundwater is not consumed and drinking water wells did not contain sulfate, it is not expected to cause adverse health effects in the population.

Lead was detected at low levels in the public water supply, groundwater wells, and subsurface soils. No comparison values or minimum risk levels have been established for lead. USEPA's action level for lead in drinking water is 15 ppb, which was slightly exceeded in the public water supply. This is the level at which corrective engineering action is recommended. Lead affects every organ and system in the body, but it is most detrimental to the nervous, hematopoietic, and cardiovascular systems. Lead is a cumulative and persistent toxicant. Although it has shown carcinogenic effects in animals, and may also be a human carcinogen, its effects upon the nervous system, especially in young children, are the main concern. Other factors such as a child's nutritional and health status affect lead absorption and its detrimental effects on the body (ATSDR, February 1992). Because of the limited occurrence of lead in the public water, and relatively low concentrations, IDPH does not expect the lead to cause adverse health problems in residents using the public water supply.

Cadmium has been detected in low levels (up to 6 ppb) on three occasions in on- and off-site groundwater monitoring wells. It was not detected in the public or private drinking water wells. Cadmium is a naturally-occurring metal used extensively in industry. It is present in tobacco, which accounts for most human exposures. Animal studies of cadmium oral exposure have not shown a carcinogenic response (ATSDR, October 1991). Insufficient evidence exists to evaluate the potential carcinogenicity by oral or dermal routes. Persons who inhale cadmium for a long time have an increased chance of getting lung cancer. Because of its limited occurrence at low levels in on-site groundwater monitoring wells and because it is not present in drinking water wells, it is not expected to cause adverse health effects in residents using the public water supply or private well water.

Zinc was detected in on-site groundwater monitoring wells at concentrations above adult and child long-term health advisory levels. This was attributed to a deteriorating galvanized well pipe, which was replaced. However, it has been detected in well G11D at levels approaching the SMCL of 5 ppm as recently as 1992. Zinc is an abundant, naturally-occurring element. It is a necessary element to human health, and the Recommended Daily Allowance (RDA) is 15 milligrams per day for males and 12 milligrams per day for females. Zinc ingestion above the RDA is advisable for pregnant or lactating females, but levels significantly above the RDA can affect the body's immune/inflammatory mechanisms. Very little data with respect to dermal exposure or carcinogenic effects presently exist (ATSDR, October 1992). It is not expected to cause adverse health effects at the levels encountered in the groundwater wells. Table 8 lists the contaminants selected for further evaluation at H.O.D. Landfill.

Toxic Chemical Release Inventory

Besides the review of currently available data on the contamination around the site, the USEPA Toxic Chemical Release Inventory (TRI) was searched for the site and local area. This database contains information on environmental releases from active industrial facilities and is used to find out the emissions from surrounding manufacturing and industrial facilities that may be contributing an additional environmental burden to a potential population of concern. The TRI for areas within a 3-mile radius of the site listed no facilities reporting emissions into the air, water, or land.

No emissions or industries in the Sequoit Industrial Park, next to H.O.D. Landfill, were identified in the TRI. A narrative that delineates the companies/sources of possible area contamination in the industrial park and their production and disposal of contaminants, as identified by WMI, is presented in Appendix A. This information is based on a 1988 environmental audit by Patrick Engineering, Inc. A map of the Industrial Park in relation to the site is presented in Figure 6.

C. Quality Assurance and Quality Control

In preparing this public health assessment, no complete quality assurance/quality control report was found. Therefore, IDPH relied on information provided in the referenced documents. The analyses and conclusions reached in this public health assessment are only valid given that the information used is complete and reliable.

Data were gathered by different agencies and companies. The sampling parameters were not always clear and did not always correspond with data previously collected from the same point. Therefore, the data must be considered as discrete sample points rather than as frequency distributions.

Groundwater samples were collected in phases in August 1987, April 1988, and May 1988, but samples were not collected from monitoring wells constructed of polyvinyl chloride. Nine monitoring well samples were reanalyzed for semi-volatile organic compounds (SVOCs) (Ecology and Environment, 1989). Data from temporary leachate piezometers, presented in the groundwater monitoring sections of the Warzyn data reports, were leachate, not groundwater, analyses. The on-site groundwater monitoring well data compilation supplied to IDPH by WMI for the period February 1985 through April 1992 did not reflect all of the data points given in the data set produced by Warzyn, Inc.

Bis(2-ethyl-hexyl)phthalate was detected at high concentrations in groundwater monitoring wells on-site, but was also detected in the laboratory blank. This compound is a common lab contaminant. Data collected before October 31, 1985, from Well G103 must be considered in light of the fact that it was replaced with well R103 after high zinc concentrations were discovered from well samples. WMI contended that a deteriorating, galvanized steel protector pipe caused the observed zinc release to the environment, which contributed, in part, to the NPL score. However, groundwater monitoring well G11D analyses have since demonstrated the presence of high zinc concentrations in groundwater. Further, a malfunctioning pump oiling mechanism that reportedly leaked up to l00 gallons (or more) of oil into municipal well 4 was discovered during video logging. Analysis of the oil showed it contained toluene, xylenes, and ethyl benzene (Warzyn, 1992).

The on- and off-site parameters given in the ATSDR Preliminary Health Assessment may be suspect due to lab qualifier and data quality control problems. No concentrations were given for off-site thallium and arsenic in the ATSDR document. Thallium concentrations noted in municipal well 4 and the private wells may be suspect because there may have been a lab matrix problem and the element was also detected in the blank.

D. Physical and Other Hazards

Newspaper reports of testimony given in public hearings opposing the site mentioned that several fires occurred in the 1970s (IEPA files, Maywood office, 1970-79). Flammable, ignitable, highly volatile, and explosive substances may have been buried at H.O.D. (IEPA files, 1979). Therefore, the potential for spontaneous combustion may exist. However, the HRS package showed there was no threat of fire or explosion that could be documented (IEPA files, 1985). The 6-foot high chain link fence that surrounds the site should restrict site access to trespassers.


To decide whether the residents near the H.O.D. site have been or are being exposed to contaminants in the landfill, IDPH evaluates the environmental and human elements that result in human exposure to chemicals. This pathway analysis consists of five elements: a contaminant source, transport of contaminants through an environmental medium, a point of human exposure, a route of human exposure, and an exposed population.

Exposure pathways are either completed or potential. Completed exposure pathways have all five pathway elementst. Completed pathways suggest that exposure to a contaminant has occurred, is occurring, or will occur. In potential pathways, at least one of the five elements is missing but could exist. Potential pathways signify that an exposure to a hazardous chemical might have occurred, might be occurring, or might occur in the future. Suspected or potential pathways can be eliminated if the site's characteristics make past, current, or future exposures unlikely.

The possibilities for human exposure to the contaminants near H.O.D. Landfill are discussed here. Table 9 describes the completed exposure pathways, and Table 10 identifies the potential exposure pathways associated with the site.

A. Completed Exposure Pathways

Public Wells

Contaminated municipal drinking water is the principal completed pathway of concern at H.O.D. Landfill. Tetrachloroethylene, vinyl chloride, arsenic, aluminum, boron, cobalt, lead, sodium, and thallium have been detected above comparison values. However, vinyl chloride, thallium, and sodium are considered the contaminants that need further evaluation. Vinyl chloride is the contaminant of most concern in the groundwater at this site.

Human exposure to contaminants in the water from municipal well number 4 through ingestion, inhalation, and dermal contact has occurred in the past, is occurring, and will continue to occur with the use of the water from this well. Of the six municipal wells, well number 4 is the major supply well and is the closest drinking water well to the H.O.D. Landfill.

The total population on the municipal supply system is about 4,400 people. The public wells, screened in the deep sand and gravel aquifer, pump in alternate cycles. Wells 1 and 4 operate simultaneously, as do Wells 2 and 3 (Warzyn, 1992). No aeration treatment system exists for the Antioch municipal wells that would disperse the volatile contaminants (Personal Communication, IEPA, Public Water Supplies).

The number of residents exposed to the contaminants in the well number 4 is difficult to determine. Those residents closest to the entry point of the distribution line of a particular well would likely be exposed to the highest concentration of contaminants. However, the concentrations at the taps should be lower than those detected at the well head. Figure 7 provides a map of the Village of Antioch's public water supply distribution system. Antioch residents have been using municipal well number 4 as a drinking water and household source since 1965. However, it is being considered for decommissioning as a public water supply source.

Because contaminants have also been detected in on- and off-site groundwater monitoring wells, the potential for their migration to the downgradient public supply wells exists, particularly municipal well number 4, and to municipal wells 3 and 5. The potential for the buried channel of the former route of Sequoit Creek to carry groundwater contaminants to drinking water wells is also a consideration. Testing is unclear whether the creek channel in the southern portion of the landfill carries contaminants to drinking water supplies downgradient of the site. Data gaps with respect to groundwater contaminants limit better characterization of this pathway. There is also the potential for the contaminants (phthalates, polynuclear aromatic hydrocarbons, and inorganics) in the deep subsurface soil samples to migrate throughout the site and to percolate to the aquifers. Additional and more complete water quality analysis of the public supply wells and groundwater monitoring wells is critical to better evaluate the potential for future municipal water supply contamination.

Private Wells

Seven residential private wells surrounding the landfill were sampled in 1987. The contaminants present above comparison values were arsenic, sodium, and thallium. Sodium and thallium are considered the contaminants requiring further evaluation. Because the residents using the sampled private wells had no other household water source, this exposure pathway is complete. Past exposures to the contaminants occurred through ingestion of the contaminated water. Future exposures are possible because use of the private well water supply for showering, bathing, cooking, and other household uses may continue. There is the remote possibility that the contaminants in the deep subsurface soils may affect the groundwater. Contaminants have been detected in on- and off-site groundwater monitoring wells, so the potential exists for chemicals to migrate to the private wells.

B. Potential Exposure Pathways


No wetlands water or sediment sampling has been done, so possible uptake of contaminants by the biota cannot be quantified. If the wetlands receive runoff and chemicals migrate from the landfill, the ingestion of its biota is a past, present, and a future potential exposure pathway for fishermen, hunters, and recreational users of the area. Ingestion of the biota from Sequoit Creek requires additional creek data to characterize. However, Sequoit Creek and the wetlands area appear not to be heavily used by hunters or recreational users. Therefore, the possibility of human consumption of contaminated biota is small. Contaminants could also migrate to the Fox River or Lake Marie where subsequent uptake by biota might occur, and area fishermen, hunters, and recreational users could ingest the contaminated biota. Although theoretically possible, the migration of contaminants in Sequoit Creek or the wetlands to the Fox River and Lake Marie and the subsequent uptake by the biota is unlikely given their respective distances from the landfill.

Surface Water

Due to inadequate surface water sampling and hydrogeological data, and the possibility of contaminant migration in groundwater, exposure to contaminants in surface water is considered a potential pathway. Since on- and off-site groundwater monitoring wells contain contaminants, Sequoit Creek and the wetlands may be vulnerable to chemical contamination. Although remote, the potential exists for chemicals to migrate from the deep subsurface soils to the groundwater and surface waters.

Surface water runoff from the landfill into Sequoit Creek and surrounding areas and wetlands may have occurred in the past, may be occurring, and may occur in the future. Surface runoff into the creek could result in erosion of site soils and downstream deposition of contaminated soils. However, the potential for substantial site erosion, although plausible in the past, is unlikely now since a four-foot clay cap and vegetation covers the site. Fishermen, hunters, and recreational users of Sequoit Creek and the wetlands may potentially be exposed through ingestion of or dermal contact with contaminated water. However, the extent of recreational use and hunting and fishing in Sequoit Creek and the wetlands appears to be small, which limits any potential exposures.


No sediment sampling data could be found, which limits characterization of this potential exposure pathway. As previously discussed, the possible contamination of Sequoit Creek, and subsequent contamination of sediments is a potential pathway for fishermen, hunters, recreational users, and site remediation personnel. However, as previously suggested, the extent of recreational use and hunting appears to be small or nonexistent, which limits potential contact with the sediments. Site personnel may contact the sediments during landfill investigation and remediation.

Soil Gas

Residents nearest to the site and employees in area commercial establishments may have encountered past, present, and future potential exposures to methane gas or other VOCs. The methane gas emitted from the landfill probably depends on the decomposition of the landfill's soil constituents and the off-gassing resulting from anaerobic decomposition of stored wastes. VOCs could also be emitted as gases or in condensate, and they may migrate off site and expose downwind populations. Future exposure of nearby residents, remediation workers, or trespassers is, therefore, a possibility. However, the methane gas is flared and dispersed throughout the atmosphere. The absence of air monitoring data near the site limits the complete characterization of this pathway.


People are not likely to come into contact with the contaminants detected in the deep subsurface soils (phthalates, polynuclear aromatic hydrocarbons, and inorganics). However, if building, excavation, or remediation occurs near the depth of the shallow soil samples (22 feet) or deeper, dermal or inhalation exposures could occur, particularly among remediation personnel. However, this is a remote possibility and is unlikely to occur in the future.


IDPH and ATSDR recognize that children can be especially sensitive to some chemicals. For that reason, IDPH evaluates children's exposures to contaminants found at the site, when appropriate. The following section of this document discusses possible health implications of exposure to contaminants from the site. Children's health issues were evaluated as part of this process.


A. Toxicological Evaluation

Vinyl chloride is the main contaminant of concern at H.O.D. Landfill. Although no increased risk appears to exist from the potential ingestion of benzene at present levels in the groundwater monitoring wells, it is discussed here because it is a known human carcinogen. The other contaminants selected for further evaluation are less problematic. Bis(2-ethyl-hexyl)phthalate is a common laboratory contaminant and was present in the blank. Thallium was also found the laboratory blank sample.

Vinyl Chloride

Vinyl chloride has been detected in municipal well number 4. The highest level noted was 6.7 ppb. The MCL for vinyl chloride is 2 ppb, and this level was exceeded in eight of the analyses. Vinyl chloride was also detected in a hydropunch groundwater sample at 188.4 ppb. Vinyl chloride may migrate from the landfill to the public or private water supply wells. It is also possible that vinyl chloride in the groundwater comes from another source; however, there is no evidence to support this possibility. Vinyl chloride has not been detected in well number 4 during the past 6 years.

Studies involving humans in occupational settings and animal studies implicate vinyl chloride as a known human carcinogen. The risk assessment for lifetime exposure carcinogenicity is currently under review (IRIS, 1993). The liver is the primary target organ. Long-term animal studies have revealed the development of hepatic neoplasms. Acute high-level exposures cause dizziness in humans, lack of consciousness, cardiac arrhythmias, liver degeneration, or death. Autopsy results show that lung and kidney irritation and inhibition of blood clotting can also occur in high exposures. Vinyl chloride disease is similar to systemic sclerosis. Hepatic angiosarcoma has been identified in workers who inhale or ingest high levels of vinyl chloride. Evidence suggests cancers of the central nervous system, respiratory tract, and lymphatic and hematopoietic systems can occur in humans following inhalation exposures.

The ingestion of water from municipal well number 4 at the maximum level of vinyl chloride detected presents a low increased risk of developing cancer. This assumes that a 70-kilogram adult drinks 2 liters of water containing 6.7 ppb vinyl chloride a day. No appreciable carcinogenic risk was added when accounting for exposures resulting from showering with water containing 6.7 ppb vinyl chloride. Since the vinyl chloride in the water is diluted throughout the system by the five other public supply wells, persons on the distribution system are not expected to ingest vinyl chloride at the concentrations detected in the analyses. It is unlikely that the level of vinyl chloride reaching Antioch residents is greater than the MCL.


Benzene has been detected in a groundwater monitoring well near the site at 8 ppb, which exceeds the CREG of 1 ppb. Its presence off-site suggests that it could possibly migrate to the public or private water supply wells. Benzene is a known human carcinogen. In occupational settings over time, changes in blood forming tissues and blood disorders have occurred. Leukemia has been associated, in many studies, with long-term benzene exposure in humans. An association with myelocytic anemia, thrombocytopenia, and acute myelogenous and monocytic leukemia has been shown in humans. Chromosomal abnormalities in bone marrow cells and white blood cells have been shown in workers exposed to high levels of benzene. The cumulative occupational exposure standard is 10,000 ppb over 40 years (IRIS, 1993). One study found a much higher risk of leukemia at lower cumulative exposure levels. Inhalation of 700 to 3,000 parts per million (ppm) can cause drowsiness, dizziness, headaches, or loss of consciousness, which quickly abate when the exposure ends.

Animal studies have shown increased cancers irrespective of sex or species of rat. However, animal and occupational studies have examined the health effects that resulted from levels up to 100 times the maximum concentration found in H.O.D. groundwater wells. The benzene level in the off-site groundwater monitoring well exceeds the MCL of 5 ppb, which is set for public water supplies. Therefore, if the benzene detected in the off-site monitoring well migrated to the public or private wells without dilution, and reached the drinking water in the same concentration (8 ppb), no increased lifetime risk of developing cancer would be expected for adults consuming the water, and no apparent increased lifetime risk would be expected in children who consume the water. No other adverse, noncarcinogenic health effects would be expected.


Thallium was detected in the public water supply at 8.91 ppb and in all private wells except one at concentrations up to 5.76 ppb. This compound was also detected in the blank and duplicate samples. Limited data on human and animal acute exposures by ingestion implicates the nervous system as the target organ. Human studies have shown cardiovascular and hepatic effects and reversible hair loss from oral exposures. Insufficient evidence exists to implicate thallium as a developmental toxin, and no data exist about its reproductive effects. However, animal data suggest thallium may affect the male reproductive system. Animal and bacterial studies implicate thallium as a genotoxin.

No data on chronic oral exposures were available nor any studies found with respect to the carcinogenicity of thallium from inhalation, oral, or dermal exposures. Human and animal studies of oral exposure suggest that thallium compounds such as thallium oxide and thallium sulfate are lethal at doses as low as 1 gram.

The concentrations of thallium detected in municipal well number 4 and six of the sampled private wells, assuming a 70-kg adult drinking 2 liters of water per day, would yield a dose of thallium that exceeds the minimal risk level. A 10-kg child, drinking 1 liter of water per day would be at a greater increased risk of noncarcinogenic adverse health effects. Dilution of the public water supply, depending on the pumping schedules, would most likely diminish the concentration of thallium in municipal well number 4.


Bis(2-ethylhexyl)phthalate, or DEHP, is an ester commonly found in the environment and is used in the plastics industry. It was found eight times in on-site groundwater wells, once at a very high level. However, it was also detected in the laboratory blank and is a common laboratory contaminant. Its maximum level of detection at 4,100 ppb greatly exceeds all comparison values.

Very limited evidence with respect to human health effects from DEHP exists, although it is considered a probable human carcinogen by USEPA. Animal studies have shown fetotoxicity and teratogenicity. Additionally, animals that ingested high doses had significant increases in liver tumor responses in both sexes of rats and mice (ATSDR, 1991).

If DEHP migrated to the public or private wells at the maximum concentration detected in monitoring wells, adults and children would be at significant risk for adverse, noncarcinogenic health effects. A moderate increased lifetime risk of developing cancer would also exist for adults and children. Migration at this level is highly unlikely due to groundwater dilution. The high level of DEHP detected may not even be accurate, given that the compound was detected only once at this level and was also present in the laboratory blank.


Sodium was detected in the public and private water supply wells and on- and off-site groundwater monitoring wells. USEPA generally recommends that persons suffering from hypertension or heart disease or those on salt-free diets should not drink water containing more than 20,000 ppb sodium. However, there are no public notification requirements if sodium levels in drinking water exceed this guidance level. The drinking water from municipal well number 4 should be diluted throughout the system, according to the well pumping schedules. Residents who drink undiluted water from private wells containing elevated sodium levels can aggravate an existing health condition. This is a remote possibility and must be considered in light of all the other dietary sources of sodium that they may also ingest.

B. Health Outcome Data Evaluation

There was no site specific health outcome data identified or generated that was appropriate for this site. If data should become available in the future, IDPH will review the data and include it in any future work done for the site.

C. Community Health Concerns Evaluation

IDPH has addressed each of the community health concerns identified at the H.O.D. Landfill as follows:

  1. Aren't there limitations inherent in risk assessment?

In doing a risk assessment of a person's chemical exposure, which is incorporated into IDPH health assessments, the assessor must rely on the best available research studies, assumptions, and hypotheses that are, by nature, extremely conservative and protective against adverse health effects in a population. National information databases and reference texts are used for the most current toxicological information. The risk assessment and public health assessment are carefully reviewed by toxicologists and other scientific professionals in state and federal agencies before they are released to the public. Any new information regarding a particular chemical or the site is added to the public health assessment, which is a dynamic document, subject to review and scrutiny. While a public health assessment cannot predict health outcomes, it can make recommendations for the protection of human health.

  1. Are there adequate quality control and technical oversight of the contractual laboratory and risk assessment work done by the potentially-responsible persons or other contractual entities?

In writing a public health assessment, IDPH assumes that the appropriate quality control and quality assurance checks and chain-of-custody procedures have been followed. The quality assurance review of the contract laboratories' analytical results is an integral and standardized component of the regulatory agencies' oversight.

  1. What contaminants at what concentrations exist in the H.O.D. Landfill, and what is the potential for their migration to the public and private drinking water wells?

Although we do not know for certain what was disposed at H.O.D. Landfill, we believe the analyses were adequate for most environmental media to say the tables in Appendix B are illustrative of the chemical contamination. Continuing investigations by IEPA seek to learn all of the contaminants involved at the site. However, people are not presently believed to be exposed to chemicals from the site at levels that are thought harmful. Exposure to higher levels is possible in the future. We cannot predict with certainty whether or not these chemicals will migrate to the private or public wells in the future.

  1. Are there radioactive materials in the H.O.D. Landfill?

No records or analyses have shown the presence of radioactive materials in the landfill.

  1. Is it safe to drink water from the public wells, particularly municipal well number 4?

Given the present levels of contamination, it is safe to drink the municipal water. The residents of Antioch have been drinking from municipal well number 4 for the past several years without apparent incident. The main contaminant of concern is vinyl chloride, which was detected in low amounts. Vinyl chloride has not been detected in the well for the last 6 years, and the water met the State's safe drinking water regulations. However, the well should be monitored regularly for evidence of further contamination and appropriate action taken in the event the contamination persists at levels above health-based standards.

  1. Will there be additional sampling done of the public and private drinking water wells?

The state monitors public water supply wells quarterly to assure the water meets regulatory standards. Additionally, private entities will monitor the wells to find if contamination exists. The appropriate agencies will periodically review the well data to decide if additional sampling is warranted.

  1. Aren't groundwater flow and fluctuations in the earth's surface mysteries, and, therefore, isn't it difficult to assess which wells will become contaminated?

Regular monitoring of wells for pollutants and a hydrogeological characterization of the site area can assess contaminant flow patterns and show which wells become contaminated over time.

  1. Shouldn't all concerned residents have their drinking water tested for contaminants?

Currently, this is unnecessary because the public wells meet state regulatory requirements for pollutants. Regulatory agencies monitor public water supplies quarterly, and agencies and private parties sample groundwater monitoring wells periodically to detect any movement of contaminants into the aquifers. Presently, no statutory water quality requirements exist for private water wells. Private well sampling conducted in the area by WMI and the Lake County Health Department have not found site-related contaminants at elevated levels. If you are concerned, you may contact IDPH, and we will let IEPA know of your concern. Whether your well is tested will depend on the proximity of the well to the site and the direction of the well from the site.

  1. How can government and private entities know which contaminants to look for in drinking water wells when the composition of the landfill is unknown?

Several compounds are commonly found at hazardous waste sites, and laboratories generally monitor for a full scan or an expanded list of contaminants in water. The state also monitors public water supplies for pollutants as mandated by law. Additionally, IDPH had access to the historical records of waste disposal at the landfill. The most toxic compounds likely to be found at a municipal landfill, even one that accepted hazardous waste, are on the list of compounds routinely checked.

  1. Is it safe to breathe the air around the landfill?

Yes. Although no air monitoring data exist, methane gas is believed to be the primary gas emanating from the site. It is likely that dispersion of the gas through the atmosphere would occur, and exposures at residences would be small. Future investigations may entail air, surface soil, or water sampling if warranted, which will help to characterize the contamination of these environmental media.

  1. Weren't all the priority pollutants found at high levels on the H.O.D. Landfill site?

No. The contaminants of concern and their respective concentrations are listed in this public health assessment.

  1. How can the municipal well number 4 contaminants occur sporadically?

Many factors dictate chemical migration through soil, water, or air, and levels can fluctuate over time. It is possible that the contaminants have already flowed through the aquifer or are no longer moving through the soil. Further monitoring will help to assess the situation.

  1. Have other Antioch municipal drinking water wells shown contamination?

Not at levels that are a health concern. All of Antioch's public water supply wells meet State regulatory limits.

  1. Isn't it unsafe to shower with water that has shown chemical contamination?

Showering in water that contains volatile organic contaminants such as vinyl chloride can expose persons to equal or greater amounts as would drinking contaminated water from the same source. Given the low vinyl chloride concentrations detected in well number 4, additional adverse health effects would not be expected from showering with this water.

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