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PUBLIC HEALTH ASSESSMENT
BELVIDERE MUNICIPAL LANDFILL #1
BELVIDERE, BOONE COUNTY, ILLINOIS

ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

The tables in this section list the contaminants of concern that are associated with the Belvidere site. These contaminants will be further evaluated in the remaining sections of this public health assessment to determine if they pose a threat to public health. The listing of a contaminant in 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 public health assessment comparison values for both carcinogenic and noncarcinogenic endpoints (discussed further below).
  4. Community health concerns

Comparison values for public health assessment are media-specific chemical concentrations that are used to select contaminants for further evaluation. These values, prioritized 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, then it will be investigated further in the remaining sections of the health assessment to determine if it poses a significant threat to public health.

Environmental Media Evaluation Guides are comparison values developed for chemicals that are potentially hazardous, 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 are not cut-off levels, but rather comparison values. They do not consider carcinogenic effects, chemical interactions, multiple routes of exposure, or other media-specific routes of exposure, and are very conservative concentration values.

Cancer Risk Evaluation Guides are estimated contaminant concentrations based on one excess cancer in a million persons exposed to a chemical over a lifetime. These are also very conservative values designed to protect sensitive members of the population.

Reference Doses Media Evaluation Guides are comparison values based on USEPA reference doses. Reference doses are estimates of a daily oral exposure to a certain chemical that is not likely to produce any noncarcinogenic adverse health effects over a lifetime. These numbers have been adjusted to protect sensitive members of the population.

Lifetime Health Advisories are concentrations an individual can be exposed to 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 is available for the chemical.

Maximum Contaminant Levels have been established by USEPA for public water supplies to reduce the chances of adverse health effects from contaminated drinking water. These standards reflect the best achievable levels considering the occurrence, relative source contribution factors, monitoring capabilities, cost of treatment, available technology, and health effects. They are enforceable limits that public water supplies must meet. These values are only considered if no EMEG, CREG, RMEG, or LTHA is available for the chemical. Proposed Maximum Contaminant Levels (PMCL) are also sometimes used in the absence of MCLs. These are proposed standards under consideration by the USEPA.

Compounds for which none of the above health comparison values exist will be considered as contaminants of concern and will be assessed in the remainder of the health assessment. Known or suspected human carcinogens will also be included if no cancer comparison value exists.

A. ON-SITE CONTAMINATION

RI field activities were conducted over a 15 month period (from December 1985 to April 1987). Media sampled in this investigation included area groundwater, on-site surface soils, surface water and sediments from the East and West ponds and the Kishwaukee River, leachate samples from around the landfill, and fish samples from the ponds and Kishwaukee River. The purpose of the RI was to characterize and locate site-related contaminants and to determine appropriate remedial actions.

Environmental sampling was also conducted during the remedial action for this site. This sampling included groundwater monitoring, limited soil sampling, and fish sampling. These results are summarized after the RI discussion in each media section.

Groundwater

Twenty six monitoring wells were installed at 20 locations on and adjacent to the landfill during the RI. Twenty five of these were installed in the upper aquifer and one in the lower aquifer. Three rounds of sampling were conducted in February, March, and September of 1986. See Figure 4 for monitoring well locations. Three of the monitoring wells are considered to be background wells in reference to the site. These wells are hydraulically upgradient of the landfill and have been installed in the upper aquifer. Groundwater flow is southwest toward the Kishwaukee River (Figures 8-11).

Many contaminants were detected in area groundwater above comparison values (Table 1) (Figures 12-19). Several contaminants detected have also been included as contaminants of concern since no health comparison values exist for them. No volatile organic compounds (VOCs) or polynuclear aromatic hydrocarbons (PAHs) were detected in upgradient background wells. One heavy metal, zinc, was detected above comparison values in background wells (Table 2).

Groundwater sampling was again conducted in May 1990. Many contaminants previously detected during the RI were not detected during this sampling event (Table 3). The main contaminants of concern during the 1990 sampling were the three VOCs benzene, ethylbenzene, and xylene. Three heavy metals, antimony, arsenic, and beryllium were also detected in concentrations above comparison values.

Soil

Soil samples were collected during two sampling rounds from 29 locations throughout the site (Figure 20) during the RI. The majority of these were collected around the landfill slopes. Four were collected in the drum disposal area; three within a 50-yard radius and one west of the drum disposal area to serve as a background sample. Composite samples were taken from 0-3 inch and 1-6 inch depths.

PCBs were the main contaminants of concern in surface soils during the RI, however, concentrations detected were low. PCBs were detected in both the landfill and drum disposal areas (Figures 14-18). Concentrations, while slightly above comparison values, were very low in the landfill area (Table 4), but substantially higher in the drum disposal area (Table 5). Several polynuclear aromatic hydrocarbons were also detected in sub-part per million concentrations in the landfill and drum disposal areas, and the area around the West Pond (Table 6) and have been included as contaminants of concern since no comparison values exist for them. Low levels of PCBs and one PAH (benzo(k)fluoranthene) were also detected in the background soil sample (Table 7). In the summer of 1990, all on-site soil with PCB concentrations above 10 ppm, mainly in the drum disposal area, was removed and replaced with clean fill (9).

A soil gas survey was also conducted at the landfill from May 13-22, 1986. The purpose of the survey was to identify VOCs in the landfill based on the assumption that volatile contaminants would migrate upward through the sandy cover materials and give indicator surface gas readings of the types of waste materials located below that location. See Figures 26-29 for survey locations and results.

Surface Water

Surface water samples were collected at eight on-site locations. Four from the Kishwaukee River, three from the West Pond, and one from the East Pond (Figure 30). No organic compounds were detected above levels of public health concern in any surface water samples. Several organic compounds were detected in samples from both ponds, however, concentrations were below levels of public health concern.

Leachate

Leachate/ponded water samples were collected at three locations on the landfill (Figure 31). Leachate seeps had been reported along the north and south faces of the landfill, but were not observed during the RI. The leachate samples collected were taken from ponded water along the western side of the landfill in an area that had previously been used as a borrow pit during landfill operations. Visual signs of contamination were not observed during sampling (16). No organic compounds were detected in leachate samples, however, several inorganic compounds were detected in these samples. Four inorganic compounds; lead, manganese, nickel, and vanadium, were detected above background levels.

Sediments

Sediment samples were collected at 10 locations corresponding to surface water sample locations (Figure 32). Six sediment samples were collected from the Kishwaukee River, eight from the West Pond, and two from the East Pond.

No VOCs or inorganic compounds were detected in any sediment samples above levels of public health concern (Figures 33-36). Several polynuclear aromatic hydrocarbons (PAHs) were detected at very low levels in samples of the West Pond (Table 8) and the Kishwaukee River (Table 9). One compound, 4-nitrophenol, was also detected at very low concentrations in both ponds and the river (Tables 8-10). Since no health comparison values exist for these compounds they have been included as contaminants of concern and will be further evaluated in this health assessment.

Fish and Invertebrate Biota

Fish and invertebrate samples were collected from several locations in both the Kishwaukee River and the West Pond adjacent to the landfill during the RI. The smaller East Pond was not sampled at this time. Twenty six fish samples and six invertebrate samples were collected and analyzed from areas upstream, downstream and adjacent to the landfill as well as from the West Pond. Ten different species were collected from three levels of the aquatic food chain; bottom feeders, pelagic feeders, and predators. The invertebrate samples, crayfish and mussels, were collected in six samples from the West Pond and the Kishwaukee River. All of these samples were analyzed for PCBs and pesticides. Three compounds, heptachlor and 4,4'-DDE (pesticides), and Aroclor 1254 (a PCB isomer) were detected in 7 of the 32 samples. No contaminants were detected in the invertebrate samples. These compounds were detected at concentrations below instrument detection limits and are, therefore, estimates of the actual extent of contamination (16). All sample concentrations were below the Food and Drug Administration's (FDA) action limits for fish. These are contaminant concentrations above which fish cannot be sold on the market due to the possibility of adverse health effects from prolonged consumption. The action limits for PCBs, heptachlor, and 4,4'-DDE are 2 parts per million (ppm), 0.3 ppm, and 5 ppm respectively. No significant difference was detected in the location of the fish samples in the river (upstream, downstream, or adjacent to the landfill). Only one sample from the West Pond (a carp) contained low levels of heptachlor (0.02 ppm) and PCBs (0.7 ppm).

Fish from the East pond, West pond and the Kishwaukee River were again analyzed for PCBs in November of 1989. While PCBs were detected in all of the samples, the concentrations were well below the FDA action limit of 2 ppm. Concentrations were generally higher in river fish samples, however, no significant difference was detected in the location of the fish samples from the river (upstream, downstream, or adjacent to the landfill).

B. OFF-SITE CONTAMINATION

Groundwater

Ten private well samples from the upper aquifer were collected from six residences along Appleton Road, three hand pump wells in Spencer Park, and from a well supplying the BCCD administration office (Figure 5) in January 1986. None of these wells is in the path of groundwater flow from the landfill and, therefore, would not be expected to be affected by it. There are no private wells within a mile downgradient of the landfill. No organic compounds were detected above levels of health concern in the residential wells, however, one compound, trichloroethylene (TCE), was detected slightly above comparison values in two of the three wells sampled at Spencer park (Table 11). Nitrite was detected slightly above comparison values in all private wells sampled during the RI. Recent sampling of the same six residential wells by IDPH, however, demonstrated no nitrite in these wells. On both sampling dates, levels of nitrates were below those of public health concern. It is unlikely that the landfill is the source of this contamination since these wells are not in the expected path of groundwater flow from the landfill. Cadmium was also detected slightly above comparison values in the well that supplies the administration building (Table 11).

C. TOXIC CHEMICAL RELEASE INVENTORY

The Toxic Chemical Release Inventory (TRI) is a series of files for the reporting years of 1987 through 1992 which contain information on estimated annual releases of toxic chemicals to the environment (air, water, land, or underground injection) and is based on data collected by the United States Environmental Protection Agency (USEPA). The information in Table 12 is taken from TRI files for records within the zip code of 61008 in Boone County. All values are given in estimated pounds of compound released per year.

D. QUALITY ASSURANCE/QUALITY CONTROL (QA/QC)

All samples were collected in accordance with IEPA and USEPA guidance, and conform to QA/QC procedures specified in the Quality Assurance Project Plan (16). Methylene chloride, acetone, and 2-butanone were detected in all matrices sampled during the RI including surface soils, groundwater, surface waters, and sediments. These compounds are recognized as common laboratory contaminants and were also detected in water field trip blanks. These contaminant concentrations were deleted from all data tables since their presence is most likely due to laboratory contamination and the concentrations at which they were detected play no role in determining the ultimate outcome of the RI.

E. PHYSICAL HAZARDS

No physical hazards were observed on-site during the August 1992 or October 1994 site visits. The landfill area is surrounded by a high fence and access is restricted by a locked gate. Several "No Swimming" signs are posted to avert visitors from swimming in the ponds. The entire BCCD property seems to be well kept, clean, and mowed.

PATHWAYS ANALYSES

To determine whether nearby residents are exposed to contaminants migrating from the site, IDPH evaluates the environmental and human components that lead to human exposure. This pathways analysis consists of five elements: a source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and an exposed population.

IDPH categorizes an exposure pathway as a completed or potential exposure pathway if the exposure pathway cannot be eliminated. Completed pathways require that the five elements exist and indicate that exposure to a contaminant has occurred in the past, is currently occurring, or will occur in the future. Potential pathways indicate that exposure to a contaminant could have occurred in the past, could be occurring now, or could occur in the future. An exposure pathway can be eliminated if at least one of the five elements is missing and will never be present. Table 13 identifies the completed exposure pathways and Table 14 identifies the potential exposure pathways. The discussion that follows these two tables incorporates only those pathways that are important and relevant to the site. IDPH will also discuss some of those exposure pathways that have been eliminated.

A. COMPLETED EXPOSURE PATHWAYS

Surface Soils

Past exposure pathways are possible from contamination of on-site surface soils. Past exposures have probably occurred in the landfill disposal areas and the drum disposal area on-site. Exposures may have also occurred via dermal contact with soils contaminated by leachate seeps.

Site workers and trespassers may have been exposed to site-related contaminants by incidental ingestion, inhalation or direct skin contact with on-site surface soils during normal landfill operations. Present and future exposures to on-site surface soils are unlikely due to remedial activities at the site including the installation of a multi-layer cap and soil removal.

A multi-layer cap has been installed on the site which includes a levelling layer, a low permeability layer, a vegetative cover, and a gas venting system. In addition to the cap, surface soils contaminated with PCBs were removed to an approximate depth of 1 foot in the drum disposal area and replaced with clean fill. Future exposure is possible if the cap is disturbed or surface soils become contaminated by leachate seeps.

Fish

Past, present, and future exposure pathways are possible from contamination of fish in the West Ponds and the Kishwaukee River. Due to past surface water runoff and groundwater discharge to these bodies of water, sediments, and possible surface water, have been contaminated. Remediation of the landfill has eliminated present and future contamination via surface water runoff. Groundwater discharge has also been addressed by the installation of a plume barrier groundwater extraction system. This system has been installed downgradient of the landfill, between it and the river. The system consists of a 1,200 foot linear array of 40 extraction wells positioned about 100 feet from the river. Future contamination may be possible if the landfill cap is compromised exposing subsurface soils, leachate, or debris.

Past fish sampling of the East and West ponds and the Kishwaukee River has detected only slight fish contamination. The contaminants detected include PCBs, heptachlor, and 4,4'-DDE. All sample concentrations were below FDA action limits for fish. Exposures are also estimated to be minimal, since these bodies of water are relatively small and fishing is not a major activity in this area. Remedial activities at the site should reduce present and future contamination of fish. Since past fish sample concentrations were below FDA action levels and contamination is not expected to increase in the future, this pathway will not be discussed further in this health assessment.

Surface Water

Future exposure pathways are possible from contaminated surface water in the Kishwaukee River and ponds. Ingestion and skin contact are routes of exposure that may occur in these bodies of water in the future, if contamination is detected in surface water. To date, contamination has not been detected in surface water samples collected from the river or the ponds above levels of public health concern. Remedial activities should eliminate possible contamination of these surface waters. Past exposures are not expected to have been significant since recreational activities (swimming) in the area have been reported as infrequent and no contamination has been detected in the past.

Private Wells from Non-Site-Related Source

Off-site groundwater sampling has not detected contamination consistent with on-site groundwater sampling. Low levels of VOCs (1,1,1-trichloroethane, tetrachloroethane, and trichloroethene) have been detected in one residential well and in all three wells in Spencer Park. TCE, cadmium, and nitrites were detected above ATSDR comparison values. TCE was not detected in on-site monitoring wells. The source of these contaminants is questionable and may be related to an old plating lagoon identified 1/2 mile east of Spencer Park.

B. POTENTIAL EXPOSURE PATHWAYS

Private wells from Site-Related Source

Past, present, and future exposure pathways are unlikely, but possible from site-related groundwater contamination at the Belvidere Landfill site. Groundwater has been contaminated by past landfilling operations and contaminants detected in on-site monitoring wells include benzene, ethylbenzene, toluene, PAHs, and PCBs. Future use of this groundwater may result in exposure to site-related contaminants by ingestion, inhalation, or skin contact.

Groundwater flow in the area is reportedly south to southwest towards the Kishwaukee River. Residents living southwest of the river are not expected to become exposed to contaminated groundwater in the future due to the installation of the plume barrier groundwater extraction system. A long-term groundwater monitoring program has also been designed to detect possible future migration. Off-site groundwater samples have indicated that past exposures to site-related contaminants were unlikely.

Public Wells

Future exposures from the contamination of the public water supply are possible, but unlikely. Public water wells are located north-northeast of the landfill (approximately 1 mile). Since these wells are located upgradient from the site and migration of contaminants are historically south-southwest, future contamination of these wells from the landfill is not likely.

Sediments

Past, present, and future exposure pathways are possible from contamination of sediments at several points of exposure near the site. Sediment samples from the Kishwaukee River and the two ponds have detectable concentrations of PAHs. Sediment contamination may have occurred as a result of surface water runoff from the landfill. Due to the low levels of contaminants detected on-site and the infrequent recreational use of the river and ponds, exposure to sediments is expected to be minimal. "No Swimming" signs are posted around the East and West Ponds and the Conservation District enforces this regulation. Swimming in the Kishwaukee River is not a frequent occurrence according to conservation personnel. Local residents may be exposed during other recreational activities (fishing or wading), but these exposures would be limited to direct skin contact and are considered to be minimal.

Remediation activities performed at the site should eliminate the future contamination of off-site sediments. Past exposures to sediments are not considered significant. ATSDR does not currently have comparison values for PAHs, but the concentrations detected in off-site sediments are comparable to concentrations typically encountered in agricultural soils and are lower than concentrations commonly detected in urban soils. Since these concentrations are comparable to background soil concentrations and recreational activities are infrequent in the area, sediments will not be discussed further in this health assessment.

Air

Past and future exposures are possible from the contamination of ambient air at the site, however, IDPH is unable to estimate past exposures to contaminants through the ambient air pathway. Since the site has been capped and is well vegetated, these exposures are expected to be minimal or non-existent in the future. Past exposures may have occurred due to landfilling operations. On-site landfill workers were probably the population at greatest risk. Future disturbance of on-site soils may create an exposure hazard in the future. Volatilization from leachate seeps in erosion channels would not be expected to result in hazardous ambient air concentrations. Constant maintenance of the landfill cap should provide adequate protection from the inhalation of site contaminants.

PUBLIC HEALTH IMPLICATIONS

A. TOXICOLOGICAL EVALUATION

The following toxicological evaluation section briefly describes the health effects associated with site-related contaminants of concern. To evaluate health effects, ATSDR has developed a Minimal Risk Level (MRL) for several contaminants commonly found at hazardous waste sites. The MRL is an estimate of daily human exposure to a contaminant below which non-cancer, adverse health effects are unlikely to occur. MRLs are developed for each route of exposure (ingestion, inhalation, and dermal exposure) and for the length of exposure, such as acute (<14 days), intermediate (15-365 days), and chronic (>365 days).

The main site-related contaminants of concern are polychlorinated biphenyls (PCBs). Trichloroethylene (TCE), cadmium, and nitrite have been detected in private wells above comparison values, however, these wells are not in the projected path of groundwater flow from the landfill. This implies that the source of these contaminants is not the Belvidere landfill. Health effects associated with exposure to these compounds at levels detected will be discussed below.

Exposure to PCBs may have occurred via contact with contaminated soils at the former drum disposal and landfill areas. PCBs were also detected in fish samples from the Kishwaukee River and on-site ponds, but will not be addressed since concentrations were very low and exposure has been determined to be minimal.

Health effects due to exposure to these chemicals may be divided into acute and chronic effects. Acute effects result from a short exposure (minutes to hours) to very high levels of a compound, while chronic effects result from a much longer exposure (months to years) to lower levels. Acute effects are usually associated with occupational exposure or accidental releases of large amounts of chemicals. Chronic exposure to low levels of contaminants is the main concern for residents around the Belvidere site.

PCBs

Polychlorinated biphenyls are a family of man-made chemicals that include over 200 individual compounds. There are no known natural sources of PCBs in the environment. These chemicals are released into the environment as mixtures and are usually oily liquids or solids that are colorless to light yellow in color and have no distinct smell or taste. Because PCBs are good insulators and don't burn easily, they have been used widely throughout industry as coolants and lubricants in transformers, capacitors, and other electrical equipment since the 1930s. Some of the PCBs that are manufactured in the United States are known as Aroclors and are labeled according to the number of carbon atoms and the amount of chlorine present in the compound (e.g., Aroclor 1260 = 12 carbon atoms and 60% chlorine content). The manufacture of PCBs in the United States stopped in October 1977 because of evidence that they are very persistent (do not readily breakdown) and can accumulate and concentrate in animals and may cause harmful effects to animals (including man). Consumer products that may still contain PCBs are old fluorescent light ballasts, certain electrical devices, and some old appliances with capacitors.

Based on the following assumptions, the chronic MRL for PCBs was not exceeded for children or adults exposed to contaminated soil in the former drum disposal area before remediation. For exposure through ingestion of contaminated soil, it has been estimated that young children (weighing approximately 10 kg) ingest about 200 milligrams (mg) of soil per day while adults (weighing approximately 70 kg) ingest approximately 100 mg of soil per day. This is an overestimate for most individuals. Children who have pica, or a tendency to eat non-food items such as dirt or sand, may ingest as much as 5,000 mg of soil per day or more. Of this total soil ingested, it is assumed that about 50% would be absorbed by the gastrointestinal (GI) tract. It is further assumed that exposure to on-site soil would only occur 60 days out of the year.

Inhalation of PCB contaminated soil particles and dermal contact with PCB contaminated soils present two more potential exposure pathways to PCBs. In estimating exposure via dermal absorption it is assumed that the average person in the area had skin contact with soil only with their hands. It is further assumed that approximately 2.7 milligrams per square centimeter (mg/cm2) would stick to the exposed skin and 1% of the PCBs in that soil would be absorbed through the skin. The average surface area for the hands of a typical child and adult are 410 and 820 cm2 respectively.

In estimating exposure via inhalation, it is assumed that the average adult breathes approximately 20 m3 of air per day and that all of the PCBs on particles less than 10 microns in size small enough to be respired will be absorbed by the lungs and circulated in the blood. It is further assumed, based on the 1990 total air particulate average, that there are approximately 25 ug/m3 of dust particulates less than 10 microns in size in the air in Boone County (11).

Estimated exposure doses prior to remediation of on-site soils also suggest that past exposures to PCB contaminated soils have not increased the risk of cancer from PCBs. PCBs are considered to be probable human carcinogens based on animal studies and limited human studies. However, to date, PCBs have not been definitively linked to cancer in humans, and some evidence, in fact, suggests that PCBs at the environmental levels observed are unlikely to be human carcinogens. Many occupational studies have been performed on PCB exposure and cancer, but they have reported conflicting results. Until more conclusive data become available, PCBs are considered a possible human carcinogen based on animal studies and limited human data.

Trichloroethylene

TCE is a member of the chlorinated solvents, a group of organic chemical compounds that contain the element chlorine. These chemical compounds are often used as industrial solvents, and exhibit similar physical and chemical properties. Physical properties include a sweet odor, colorless in both liquid and gas phases, and a high rate of volatilization or vaporization. These chemicals are also commonly included in a group of volatile compounds known as volatile organic compounds (VOCs) because of their high rate of volatilization. Chlorinated solvents are man-made compounds that do not occur naturally in the environment.

TCE was detected in two wells in Spencer Park at levels above health comparison values, however, based on the following assumptions, no acute or chronic health effects would be expected from drinking water from the TCE contaminated wells at Spencer Park. It has been assumed that the average child (10 kg) and adult (70 kg) drinks 1 and 2 liters of water per day respectively. These consumption rates are over-estimates since it is unlikely that a person would consume that much water during a day at the park. Dose calculations using these assumptions were far below ATSDR's intermediate MRL and also below levels at which long-term health effects would be expected. No increased risk of cancer from drinking water contaminated with TCE at the concentrations detected in the three wells would be expected.

Health professionals have much to learn about how TCE might affect people exposed chronically to low levels. However, it is generally believed that the chances of toxic effects occurring at low levels are small. The main concerns associated with low-level chronic exposure to this compound are generally adverse reproductive outcome, and neurotoxicity.

Cadmium

Cadmium is a metal that occurs naturally in the earth's crust. It is used extensively in industry for such products as Nickel-Cadmium batteries (Ni-Cad), paint pigments, welding materials, and galvanizing agents. Cadmium is also present in cigarette smoke, which is responsible for the majority of human exposure. Once in the body, cadmium has no known physiological function.

Cadmium was detected in the well that supplies the BCCD administration building above health comparison values, however, based on the following assumptions, no acute or chronic health effects would be expected from consumption of this water. It has been assumed that only adults would consume substantial amounts of water from this well and that exposure would occur five days a week, 50 weeks out of the year. It has been further assumed that only 1 liter of water would be consumed per day. Calculated exposure doses using these conservative assumptions were below ATSDR's chronic MRL.

Nitrates and Nitrites

Nitrates (NO3-) and nitrites (NO2-) are naturally occurring compounds that are part of the nitrogen cycle. In agricultural areas, nitrogen-based fertilizers are a major source of groundwater contamination for shallow aquifers that provide drinking water for area residents. A 1990 USEPA survey found that approximately 1.2% of community wells and about 2.4% of rural private wells had nitrate levels in excess of federal drinking water standards (2). Nitrate levels may also fluctuate in rural areas as agricultural practices vary throughout the year; nitrate levels would be expected to be the highest during the spring and early summer months when fertilizers are applied to crops. Other sources of nitrate contamination in groundwater include animal wastes (e.g., feed lots and farms), human waste contamination from septic systems, and natural plant and animal biodegradation processes.

Nitrates are reduced to form nitrites in the body which are the toxic agents. Unless favorable conditions exist for reducing nitrates to nitrites, ingested nitrate is metabolized and excreted without producing apparent adverse effects (2). The effects of nitrite are the same whether they are ingested as nitrite or ingested as nitrate and reduced to nitrite in the gut.

Nitrites were detected in all of the private wells sampled during the RI, including the residential wells. However, no nitrite and low levels of nitrates were detected in recent sampling of the six residential wells conducted by IDPH. Based on the assumptions that a child (10 kg) and adult (70 kg) consume 1 and 2 liters of water per day respectively, exposure to nitrites may have occurred above USEPA's chronic reference dose (RfD). This value, similar to ATSDR's MRL, is a concentration at which no adverse noncarcinogenic health effects would be expected from a daily exposure over a 70 year lifetime. No adverse health effects in children older than six months or adults would be expected from levels detected in private wells during the RI.

Infants to 6-months old may have experienced minimal health effects if the water was used to mix baby formula. The principle mechanism of toxicity involves hemoglobin, the agent responsible for transporting oxygen in the blood. Nitrite transforms the iron in hemoglobin so that it cannot reversibly bind oxygen or transport circulating oxygen (2,13). This transformed hemoglobin is referred to as methemoglobin. The resulting condition is oxygen deprivation or methemoglobinemia (also referred to as blue baby syndrome), which may lead to cyanosis, cardiac irregularities, circulatory failure, and central nervous system depression. By the time an infant reaches 6 months of age, he/she will have developed sufficient levels of an enzyme (methemoglobin reductase) to be protected from nitrite toxicity. Minimal methemoglobinemia may have resulted in infants from consumption of this water; however, no cases have been reported to the Boone County Health Department.

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, it will be reviewed and included in this document.

C. COMMUNITY HEALTH CONCERNS EVALUATION

IDPH has addressed the community health concerns associated with this site as follows:

  1. Will private wells in the area of Belvidere site become contaminated? Can wells be developed in the future in the area of this site?

    Off-site private well sampling has not revealed extensive contamination. Residential wells located to the southwest of the Kishwaukee River are in the direction of groundwater flow from the landfill. The installation of the plume barrier groundwater extraction system should intercept groundwater between the landfill and the river, ensuring that contaminants do not migrate to residential wells. Monitoring wells installed at the Belvidere site should also detect the migration of site-related contaminants before residential wells become affected. Residential wells could be installed in the area of the site in the future after contaminant migration plumes and non-site related nitrate plumes have been accurately identified and remediated.

  2. Can people drink the water from the wells located in Spencer Park?

    TCE has been detected in the Spencer Park wells. IDPH estimated an exposure dose and a cancer risk from drinking the water from these wells with the concentrations of TCE reported in the laboratory analysis. The estimated exposure dose is below ATSDR's intermediate MRL for TCE. The cancer risk associated with drinking water from the Spencer Park wells was estimated to be no apparent increased risk. At this time, no adverse health effects would be expected from drinking water from the Spencer Park wells. This may change in the future if concentrations of TCE increase or other contaminants are detected in these wells.

  3. Is it safe to eat the fish from the Spencer Park ponds or the Kishwaukee River?

    The concentrations of contaminants detected in fish samples collected from these bodies of water are below FDA action levels. IDPH does not anticipate adverse health effects from the consumption of fish from these waters. Adverse health effects may occur in the future if these waters become contaminated above levels of public health concern, but this is not expected due to previous remedial activities conducted at the site.


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