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1. ATSDR > Public Health Assessments & Consultations

The tables in this section list the contaminants of concern. We evaluate these chemicals in the subsequent sections of this public health assessment and determine whether exposure to them has public health significance. ATSDR selects and discusses a chemical as a contaminant of concern based upon the following factors:

1. the chemical has no comparison value and/or may be toxic to humans at specified levels;
2. the comparison of on-site and off-site concentrations with health assessment comparison values for (1) noncarcinogenic endpoints and (2) carcinogenic endpoints;
3. an evaluation of the field data quality, laboratory data quality, and sample design;
4. community health concerns related to a particular chemical.

Comparison values for this public health assessment are contaminant concentrations in specific media that are used to select contaminants for further evaluation. Sample data provided are documented in the Final RI report.

The data tables include the following acronyms:

CREG	=	Cancer Risk Evaluation Guide. CREGs are estimated contaminant concentrations based on a one excess cancer in a million persons exposed over a lifetime. They are calculated from EPA's cancer slope factors.
LTHA	=	Lifetime Health Advisory (for drinking water). The LTHA is derived from the Drinking Water Equivalent Levels for noncarcinogens. For noncarcinogenic organic and inorganic compounds, LTHAs are 20% and 10% respectively of the DWEL. For possible carcinogens, the LTHA is divided by an additional factor of 10.
MCL	=	Maximum Contaminant Level (for drinking water). MCLs represent contaminant concentrations that EPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an exposure rate of 2 liters of water per day.
NAS	=	National Academy of Sciences. It has been suggested by the NAS, that where water supplies contain more than 20 ppm, dietary restriction to less than 1 g is difficult to achieve and maintain.
ppb	=	Parts per billion

The Toxic Chemical Release Inventory (TRI) is a EPA database that contains information on chemical releases of industries in the United States. It is used to determine the potential sources of contamination near NPL sites. A computer search was conducted of all available toxic release inventories (TRI 87-90) data to determine the number of industries near the site within the City of Zionsville (zipcode = 46077). The data did not show any industries with chemical releases in Zionsville, Indiana, during 1987 to 1991.

All chemicals found in sampled media have been assessed for adverse health effects and are listed in the tables in the appendices at the end of this public health assessment. These tables also include the depth of soil samples, the location of all samples, and each chemical's sample concentration range.

A. On-site Contamination

Surface Soil - Phase I

On-site surface soil samples listed in the RI report were collected in December 1984. All samples were collected at a depth of 2 inches (see Figure 2).

Three grab samples of soil were taken from the landfill. One sample, NSL-SL022-01, was collected on the east side of the landfill surface. Two samples, NSL-SL020-01 and SL021-01, were collected from the southwest side of the landfill. Contamination was detected in the surface soils at one location, remote from the landfill, where the owner allegedly sprayed leachate pumped from the leachate collection tanks. Two organic chemicals, acetone and methylene chloride, were found in samples SL020-01 and SL02201. They are not considered contaminants of concern because of the low levels found and/or laboratory contamination of the samples.

Inorganic chemicals were detected in the surface soil samples. Aluminum is not considered a contaminant of concern as it is one of the most common natural constituents of soil, and because it was found at levels much lower that the average adult daily intake, as well as lower than the levels normally found in eastern United States soil.

Calcium, copper, magnesium, and potassium are considered to be essential human nutrients and are generally not believed to be toxic. These four inorganic chemicals are not considered to be contaminants of concern in this or any other medium sampled from this site.

The contaminants of concern in the on-site surface soil are listed in Table 1.

Table 1. Contaminants of Concern in On-Site Surface Soil Samples, Phase I.

* No comparison value available

The hydrogeologic investigation which included subsurface soil sampling was conducted at the NSL site from December 1984 through January 1985. A total of 39 subsurface samples were collected from 11 boreholes. Sample depth categories consisted of shallow (> 3 inches to 5 feet), mid (5 feet to 13 feet), and deep (13 to 30 feet). The depths have been rounded to the nearest whole number. (EPA Remedial Investigation Report)

Fifteen monitoring wells were proposed for installation at locations along the perimeter of the NSL site (Figure 3, Appendix A). Eleven of the 15 boreholes were sampled. The four un-sampled boreholes (NSL8S, NSL9S, NSL10S, and NSL11S) were in close proximity to the deeper boreholes (NSL8D, NSL9D, NSL10D, NSL11D, NSL12D, NSL13D, NSL14D, NSL15D, and NSL17S respectively) and only the deeper boreholes were sampled except for NSL17S, which also is a shallow borehole.

The area of greatest contamination in the sand and gravel water-bearing units was southwest of the landfill at NSL12 and NSL13.

Subsurface soils in the glacial till showed contamination at all sampling locations. The greatest contamination in glacial till subsurface soil was in the southwest corner of the site, at NSL13, NSL12, NSL14, and NSL8S, and on the east side of the landfill at NSL11S. Lesser concentrations of contaminants were found along the north, south, and west sides of the landfill.

The contaminants of concern in the subsurface soil are listed in Table 2.

Table 2. Contaminants of Concern in On-Site Subsurface Soil Samples, Phase I.

* No comparison value available

Glacial till is a mixture of clays, silts, sand, and gravel, and exists around the NSL site from the surface or just below the loess to depths up to 40 feet. A layer of sand and gravel exists at the NSL site below the glacial till and ranges in thickness from approximately 2 to 23 feet.

No strata below the sand and gravel were studied in the RI. Results from the ECC RI, however, suggest that the following strata exist at the NSL site:

Lower Glacial Till	-	Glacial till consisting of very hard, silty clays approximately 120 feet thick.
Lower Sand & Gravel	-	A sand and gravel layer about 15 feet thick at a depth of about 150 to 165 feet below surface grade.

The wells were installed in four well nests consisting of two wells per nest. Each nest consisted of a shallow well screened in the first groundwater encountered, and a deeper well screened in the first coarse-grained, water-bearing unit. Four other shallow wells were installed in proximity to deeper historical monitoring wells. Shallow wells ranged from 11.5 feet to 24.5 feet, and deep wells ranged from 31 to 39.5 feet below surface grade.

In February and April 1985 the following samples were collected: 19 samples from new and existing monitoring wells, one soil boring piezometer sample (SBP), two groundwater duplicate samples, two groundwater field blank samples, and one matrix spike duplicate sample (Figure 3, Appendix A). A total of 51 monitoring wells and SBPs have been installed at the NSL site. The wells samples consisted of seven existing monitoring wells (MW1 through MW7), two SBPs (65 and 77), and 14 RI monitoring wells for a total of 23.

Monitoring wells NSL10S and SBP77 were bailed dry and were slow in recovering; therefore, no sample was collected at SBP77 and only enough water for the organic analysis and metals fraction of the inorganic analysis was collected from monitoring well NSL10S. Monitoring wells NSL8S and NSL8D were not sampled because they had been destroyed by a landfill vehicle in February 1985. In April 1985 EPA returned to the NSL site to sample monitoring wells NSL8SA and NSL8DA, which replaced the two demolished wells. Two monitoring well samples and one groundwater field blank sample were collected. A second effort was made to sample SBP77, but due to its slow recharge, sampling was unsuccessful. In May 1985 Phase II groundwater samples were collected concurrent with the Phase II surface water, bottom sediment, and residential well water samples. Samples were collected within the glacial till and the sand and gravel water bearing units (Figure 3, Appendix A).

The 23 monitoring wells sampled during this effort were selected by the EPA and its contractor, and the ISDH. The wells sampled consisted of seven existing monitoring wells, MW1 through MW7 (sand and gravel water bearing units), installed in December 1979; two SBPs, SBP65 and SBP77 (sand and gravel water bearing units), installed in 1982; and 14 RI monitoring wells (glacial till, and sand and gravel water bearing units), installed in December 1984 and January 1985.

Contamination was found in the glacial till groundwater on all sides of the landfill. Monitoring well NSL16 on the northeast corner of the site, had the greatest number and highest concentrations of contaminants.

The majority of the contaminants were found near the southwest corner of the NSL site. Lower levels of contamination were found in the sand and gravel water-bearing unit along the south side of the site.

All chemicals detected during the Phase I and II sampling are listed in Appendix B. The highest chemical concentration found in either Phase I or II was used as the criteria for selecting a contaminant of concern. Contaminants of concern for Phases I and II in on-site groundwater are listed in Table 3.

Table 3. Contaminants of Concern in On-Site Groundwater Samples, Phases I & II.

* - No comparison value available
¹ - Classified as a known human carcinogen by the National Toxicology Program.
² - Classified as a probable human carcinogen by the EPA.
A - EPA Action Level

In May 1985 three leachate sediment (LS) and two leachate Liquid (LL) samples were collected (Figure 4, Appendix A). Sediment and liquid leachate samples were collected on the east side of the NSL site at the discharge point of a culvert located under the landfill roadway, approximately 460 feet west of monitoring well MW5. Two liquid leachate samples were collected from the drainage ditch constructed by the landfill owner. The third leachate sediment sample was collected at the surface of the southwest corner of the landfill, north of monitoring well MW2.

Leachate sediment samples collected on all sides of the landfill showed contamination. The sample from the southwest portion of the site revealed the highest contamination, including pesticides. Minimal contamination was found in leachate liquid.

A background soil sample was collected at the northeast side of NSL and is identified as NSL-SL028-01. The sample was collected approximately 125 feet north of the landfill road along the fence and tree line.

The contaminants of concern in the liquid and solid leachate samples are listed in Table 4.

Table 4. On-Site Leachate (Liquid and Solid) Sample Results, Phase II.

* - No comparison value available
¹ - Classified as a probable human carcinogen by the EPA.

Groundwater - Private Wells

In May 1985 residential well samples were collected concurrent with the Phase II groundwater, surface water, and bottom sediment sampling investigation.

Prior to collecting samples, existing wells in the vicinity of the NSL site were inventoried. In April 1985 a door-to-door survey of the residential homes south and southwest of the site was conducted in order to gather information regarding their wells.

Well locations were determined, and when possible, the depth of the well was obtained either through knowledge of the owner or from available records.

From the survey it was determined that most of the homeowners only knew the approximate depth of their wells; therefore, a file search at the ISDH was conducted. Well logs for wells within a 1-mile radius of the NSL site were collected.

A total of seven samples were collected (see Figure 5, Appendix A). The sample number and well depths for the private wells are NSL-RW001-01 (52 feet), NSL-RW002-01 (40 feet [on-site well]), NSL-RW003-01 (40-60 feet), NSL-RW004-01 and NSL-RW006-01 (duplicate) (47 feet), NSL-RW005-01 (122 feet), and NSL-RW007-01 (blank).

Sodium was the only contaminant of concern found in private wells (Table 5).

Table 5. Contaminants of Concern in Off-Site Private Well Samples, Phase II.

Surface Water and Bottom Sediment

In December 1984 (Phase I) and May 1985 (Phase II), surface water and sediment samples were collected from eight locations in Finley Creek and the unnamed ditch (Figure 4, Appendix A). It was discovered that the landfill owner re-channeled Finley Creek to a location farther south of the NSL site in 1980. Sample NSL-SW/SD004-01 was collected in this former section of the creek.

Ten surface water and ten sediment samples, including two duplicate and field blank samples, were collected from downstream to upstream. Surface water samples were collected from the center of the creek or ditch, and prior to the collection of the sediment samples to avoid sediment fines in the water samples. A bottom sediment sample was collected at each surface water sample location in an area along the bank where there was evidence of sediment deposits along the creek or ditch bank, or below the surface water sampling point.

Sample locations for both phases were as follows: one sample upstream of the site in Finley Creek, one sample upstream of the site in the unnamed ditch, four samples in Finley Creek adjacent to the landfill, one sample between the former ECC and the landfill in the unnamed ditch, and one sample downstream of the site and the confluence of Finley Creek. Phase II samples were collected in the same general area as Phase I, except for NSL-SW/SD0011-02.

The greatest number and highest concentrations of contaminants found in surface water and sediments were detected at sampling point SD008/SD009, downstream of the confluence of the unnamed ditch and Finley Creek. Above the confluence, sediments showed contamination in Finley Creek at SD006 and the unnamed ditch at SD010.

Polychlorinated biphenyls (PCBs) were detected in sediment samples SD008/SD009, and at SD004 (in a former segment of Finley Creek on the south side of the landfill). The pesticide dieldrin was detected at SD011 in Finley Creek in the southeast portion of the site.

The contaminants of concern in the Phase I and II surface water and sediment samples are listed in Table 6.

Table 6. Contaminants of Concern in Off-Site Surface Water and Sediment Samples, Phases I & II.

* No comparison value available

Aquatic Biota

Two studies, a bioaccumulation study on freshwater mussels and a biological assessment of stream ecosystems, have been performed in the vicinity of NSL.

In the first study, the ISDH suspended live freshwater mussels, (Lampsilis radiata siluoides) in wire baskets at four locations (two upstream and two downstream of the site) on April 24, 1981 (Figure 6, Appendix A). On June 9, 1981 mussels were taken out of the stream, wrapped in solvent-rinsed aluminum foil, and kept frozen until analyzed. Each sample consisted of five mussels.

The second study was performed by the Department of Zoology, Depauw University, from 1978 to 1980 as part of a larger biological monitoring program of fish populations and benthic macroinvertebrates. One of the areas studied was the Eagle Creek watershed, including Finley Creek. Fish were collected using an electric seine. Samples were collected both upstream and downstream (Figure 7, Appendix A). Sampling normally took place once a month in May, June, July, August, and October in 1978, 1979 and 1980.

Results from the mussel bioaccumulation study showed that arsenic was the only contaminant found downstream at levels higher than upstream of the NSL site.

Results of the biological monitoring program assessment of fish population reported that the fish population is much less downstream of the site than upstream. Samples taken downstream also consistently ranked lower in density, biomass or number of families than upstream samples.

Environmental Data Gaps

Due to the lack of off-site surface soil sampling and ambient air monitoring, it is not possible to characterize the extent of contamination in these two media.

C. Quality Assurance and Quality Control

In preparing this health assessment, the ISDH relies on the information provided in the referenced documents and assumes that adequate quality assurance and quality control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting.

In the surface soil samples, methylene chloride, 2-butanone, and phthalates were detected in the laboratory and field blanks and may be laboratory and/or field contaminants.

The surface water samples contained phthalates, acetone, and methylene chloride, which were detected in several samples, but were also detected in field blanks and are considered likely laboratory or field contaminants. Mercury was detected in a number of samples but was also detected in the field blank and is considered to be a laboratory or field contaminant.

In the subsurface soil, ethylbenzene, 1,1,1-trichloroethane, xylenes, methylene chloride, 2-butanone, and acetone were identified in the field samples and in the laboratory or field blanks, limiting the use of this data. Butyl benzyl phthalate, pyrene, and di-n-butyl phthalate were also identified in the field samples and in the laboratory blanks, limiting the use of the data.

Acetone, 2-butanone, and methylene chloride were identified in the on-site groundwater, and in the laboratory blanks limiting the use of this data. Di-n-butyl phthalate was also detected in the laboratory and field blanks thus limiting the use of the data.

Methylene chloride, acetone, and 2-butanone were laboratory/field contaminants. The values for acetone and 2-butanone, however, were 10 times higher than the associated laboratory and field blanks in the solid leachate sample. These values will be considered valid, and useable.

The off-site private well samples contained methylene chloride, 2-butanone, and phenol. Methylene chloride and 2-butanone were found in the laboratory blank and are considered to be present due to laboratory possible/probable contamination.

The values for 2-butanone and phenol were estimated and, therefore, are considered not valid or usable.

D. Physical and Other Hazards

The on-site leachate contains chemicals which could cause burns upon contact. Another threat or hazard from the site is exposure of site workers to uncovered garbage. The cap on the top of the landfill mound has for the most part eroded, exposing domestic garbage. The garbage poses a fall or trip hazard where in an individual could fall landing on sharp edges resulting in cuts and abrasions. The remediation of the site includes soil\gas venting. Venting mechanisms are already in place; therefore, hazards from build up of gas to explosive levels is limited.

To determine whether nearby residents are exposed to contaminants migrating from the site, ATSDR 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.

ATSDR 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, however, require that at least one of the five elements is missing, but could exist. 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. We assume that all individuals working on-site follow the site specific health and safety plan, thus they are not considered as exposed populations.

Table 7 identifies the completed exposure pathways, and Table 8 identifies the potential exposure pathways. The discussion that follows these two tables incorporates only those pathways that are important and relevant to the site. We also discuss some of those exposure pathways that have been eliminated.

A. Completed Exposure Pathways

Off-Site Groundwater - Private Wells

Results of the hydrogeologic investigation have shown the existence of four hydrogeologic units in the area, a shallow saturated zone, a shallow sand and gravel aquifer, a clayey silt and silty clay zone, and a deep confined aquifer. Possible groundwater contaminant sources at the NSL site include solid and liquid leachate, and the contaminated sub-surface soil. Migration of soil contaminants to the shallow saturated zone has occurred on-site as evidenced by high levels of contaminants in well NSL16. Further leaching of soil contaminants to the saturated zone is expected to be slowed due to the presence of a compacted silty-clay cap on the entire site. Contamination of the shallow sand gravel aquifer may have occurred, however, by migration through the silty clay.

The residents surrounding the NSL site all use private residential wells for their water supply. Sampling data of these wells indicate a high, possibly site related sodium contamination in this water. High levels of sodium were also found in the on-site groundwater and liquid leachate samples indicating the site as the possible source of sodium. Adverse health effects could occur in individuals using private wells as their primary source for drinking water. Inhalation and dermal contact are not exposure routes for adverse health effects from water containing high levels of sodium.

These private wells are also a potential pathway for residents to ingest, inhale, or be dermally exposed to site related organic and inorganic chemicals which were found in the on-site monitoring wells but not in the private wells. If the groundwater in either the glacial till or sand and gravel water-bearing units is consumed as a potable water supply in either a residential, commercial, or industrial setting, there is a potential for adverse health effects including cancer.

While organic chemicals do not appear to have migrated to the residential wells, it must be assumed they have a potential of doing so because of the groundwater flow migrating from northeast to southwest. Migration of contaminants to the nearest residential wells surrounding the site is not indicated, however, by the results of the residential well sampling.

The deep confined aquifer below the site has not been found to be contaminated. Contamination of the deep confined aquifer is unlikely because of the thick sequence of low permeability soils that act as a confining layer. Future migration of on-site contaminants to the deep aquifer is highly unlikely due to the upward vertical hydraulic gradient. The most probable pathways for contaminant transport in the groundwater are through migration from the shallow saturated zone or from the shallow sand and gravel aquifer to the unnamed ditch or Finley Creek.

All chemicals found in the off-site groundwater at levels of health concern will be evaluated for their health effects in the Toxicological Evaluation subsection of this public health assessment.

B. Potential Exposure Pathways

Leachate

High concentrations of contaminants were not found in leachate liquids. The presence of contaminants in leachate sediments, however, indicates that past discharges of contaminants from NSL have occurred, and could recur in the future.

Based on surface drainage patterns, only the contamination south of the landfill can be attributed exclusively to releases from NSL. Contamination in the unnamed ditch and downstream of the confluence with Finley Creek could be from ECC or NSL, or both.

This medium is considered a potential pathway through ingestion, inhalation, and dermal contact. Current risk to public health is negligible, however, since long-term ingestion, inhalation, and dermal contact is highly unlikely. Leachate seeps, however, represent the potential for future release of contaminants which could result in adverse health effects for humans.

Off-Site Surface Water and Sediment

The presence of contamination in surface water in the unnamed ditch and downstream of the confluence with Finley Creek at higher than upstream concentrations indicates that contaminants are presently being released to the unnamed ditch.

The location of the westward-trending gully beneath the NSL and the presence of contaminants in the surface water in the unnamed ditch and the groundwater in the southwest side of the landfill indicates that the gully may be a conduit for contaminants migrating from the landfill. The portions of the old Finley Creek overlain by the south side of the NSL may also be a conduit for contaminant migration from the landfill.

Contaminants in the surface water may volatilize, precipitate, or adsorb in sediments, or remain in solution and be transported downstream to Big Eagle Creek and eventually the Eagle Creek Reservoir. Individuals may be exposed by wading in the creek, incidentally ingesting contaminated water during recreational activities, or ingesting fish which have bioaccumulated contaminated sediments.

Contaminants in stream sediment may dissociate and re-enter the surface water. The contaminants can then be re-suspended during high water flow and carried downstream. During low water flow periods, contaminated sediments may be exposed along the stream banks and may be transported as dust.

Although the water in Finley Creek is very shallow, individuals (particularly children) may participate in recreational activities, and they could potentially be exposed by dermal contact and less significantly by inhalation to site related chemicals found in the off-site stream sediment. It is important to note, however, that because the exposure to site related chemicals would not be for an extended period of time, this medium is not considered a main source of contaminant exposure to humans.

Surface Soil

Because of the protective cap and vegetation on-site, the exposure through surface soil would be minimal. Surface soil samples of less than 3 inches have been taken. In seasonal dry conditions during pass and present on-site activities, contaminated windblown dust could travel to neighboring residences. As noted during the site visit, there are areas of exposed garbage on top of the landfill. Routes of exposure to residents surrounding the NSL site are inhalation, incidental ingestion, and dermal contact.

The extent of off-site surface soil contamination due to on-site failure to cover refuse, past surface burning, underground fires, and leachate is not known. Off-site surface soil sampling will be necessary to further evaluate this exposure pathway.

Aquatic Life

As mentioned in the sediment pathway, both the unnamed ditch and Finley Creek receive groundwater and surface water runoff from the NSL site. Once contaminants enter the surface water, they will either volatilize or absorb to sediment, or experience large dilutions before reaching the Eagle Creek Reservoir.

Mussels are bottom dwellers and feeders; therefore, they are likely to bioaccumulate contaminants found on sediments or in surface water. The levels of contaminants found in the bioaccumulation study in mussels may be indicative of the levels of contamination found in some fish in Finley Creek.

Analyses results for contaminants found in mussels included: lead, mercury, PCBs, arsenic, dieldrin, and chlordane. Arsenic was the only contaminant found at higher levels downstream than upstream. Individuals could be exposed indirectly to site related contaminants by eating fish caught in Finley Creek. To adequately characterize the extent of fish contamination in Finley Creek, additional fish sampling is needed.

PUBLIC HEALTH IMPLICATIONS

In this subsection we will discuss the health effects of persons exposed to specific chemicals, evaluate state and local health data bases, if available, and address any existing community health concerns.

A. Toxicological Evaluation

ATSDR has developed toxicological profiles on several chemicals that have been found at this site. These profiles provide information on health effects, environmental transport, human exposure, and regulatory status.

Sodium was the only chemical measured in drinking water wells above comparison values; therefore, adverse health effects from ingestion of the maximum concentrations for sodium will be discussed later. A toxicological profile for sodium has been provided below along with a toxicological profile for each of the contaminants of concern found in the off-site groundwater, although off-site groundwater is at present not a completed pathway.

Sodium

Long-term ingestion of high concentrations of sodium are believed to be associated with the development of hypertension and would complicate clinical treatment of hypertensive patients on salt-restricted intakes. Sodium was found in elevated levels in the on-site surface water, off-site groundwater, and private well water.

Because intake restrictions of sodium are often part of hypertensive therapy, the levels of sodium in the off-site groundwater could represent a significant health concern to past residents who used private wells. Typically, prescribed low-sodium diets attempt to limit sodium intake from food and water to either 2, 1, or 5 grams (g) in a 24-hour period. It has been suggested by the National Academy of Sciences (NAS) that, where water supplies contain more than 20 ppm, dietary restriction to less than 1 g is difficult to achieve and maintain. (NAS, Drinking Water and Health)

Arsenic

Inorganic arsenic has been determined to be a cancer-causing agent. The single most characteristic effect of long-term oral exposure to inorganic arsenic is a pattern of skin changes. This includes a darkening of the skin and the appearance of small "corns" or "warts" on the palms, soles, and torso. While these skin changes are not considered to be a health concern, a small number of the corns may ultimately develop into skin cancer. (ATSDR Draft Toxicological Profile for Arsenic)

Despite all the adverse health effects associated with inorganic arsenic exposure, there is some evidence that a small amount of arsenic in the normal diet (0.01- 0.05 ppm) may be beneficial to your health. Arsenic levels found here are higher than the EPA chronic oral RfD for this chemical. Possible health effects associated with the ingestion of the levels of arsenic found here are irritation of the stomach and intestines with symptoms such as pain, nausea, vomiting and diarrhea. This chemical is currently only a potential contaminant of residential wells.

Benzene

Benzene is a naturally-occurring substance produced by forest fires and is present in many plants and animals, but benzene is also a major industrial chemical made from coal and oil. How benzene affects health depends on the level and duration of exposure. (ATSDR Toxicological Profile for Benzene)

Benzene was detected at 110 ppb in the on-site groundwater. An estimated daily ingestion exposure dose was calculated. The value was considerably lower than 5 ppb, the maximum contaminant level in drinking water for this chemical. Benzene is a proven cancer-causing agent in humans. Based on the estimated daily ingestion dose, there is no apparent risk of cancer increase due to the exposure of this chemical at the specified levels. This chemical is currently only a potential contaminant of residential wells.

Di(2-ethylhexyl)phthalate

Bis or di(2-ethylhexyl)phthalate (DEHP) is a manmade chemical that is added to plastics to make them flexible. DEHP can enter the body by contaminated food, water, or air. Almost all of the DEHP that enters the body from food, water, or air is taken up into the blood from the lungs and intestines. Small amounts may also enter the body by skin contact.

Most of what is known about the health effects of DEHP comes from animal studies, especially studies of rats and mice. Because DEHP appears to affect rats and mice differently than humans and other animals, it is difficult to predict the health effects in humans using information from animal studies. There have been no studies of workers exposed to DEHP that indicate it causes cancer in humans. (Draft Toxicological Profile for Di(2-ethylhexyl)Phthalate)

DEHP was found at 26 ppb in the on-site groundwater. When DEHP is released into soil, it usually does not move very far away from where it was released. It dissolves very slowly in water. DEHP does not evaporate easily, and thus very little will be present in the air even near sources of production. An estimated daily exposure dose was calculated. The value was much less than the chronic oral RFD for this chemical. At present this chemical is only a potential contaminant of the residential wells.

Chloroethane

Chloroethane, which is also called ethyl chloride, is a manmade compound. Human activities are responsible for almost all the chloroethane released into the environment. Most chloroethane released into the environment ends up as a gas in the atmosphere, but small amounts may enter groundwater as a result of filtration through soil. Once in the atmosphere, chloroethane breaks down fairly quick by reacting with substances in the air.

Chloroethane will most often enter the body through inhalation, although it may also enter the body through contaminated drinking water. It is not known if chloroethane produces cancer in humans. There is currently no oral chronic Minimal Risk Level (MRL) for this chemical but, there is an intermediate inhalation MRL. The MRLs are estimates of levels posing minimal health risk to humans. They include adjustments to reflect human variability and extrapolation of data from laboratory animals to humans (ATSDR Toxicological Profile for Chloroethane). Air monitoring has not been done for this site, unfortunately, thus an estimated daily inhalation dose exposure cannot be calculated.

Chloroethane was found at 24 ppb in the on-site groundwater. The possible routes of exposure are through ingestion, dermal contact, and inhalation. The health effects resulting from short- or long-term human ingestion or exposure to water containing chloroethane are not known. This chemical was not found in the residential wells. At present, chloroethane is a potential contaminant of private wells surrounding the NSL site.

Lead

Lead is found in the earth's crust as a naturally occurring metal. Due to human activities (use of leaded gasoline) lead has spread to the air, drinking water, rivers, lakes, oceans, dust, soil, and thus animals and plants.

Lead can enter the body through inhalation (lead dust), ingestion (lead contaminated foods), and only small portions will absorb through the skin. Lead is partitioned first in the soft tissues (liver, kidneys, lungs, brain, spleen, muscles, and heart). After several weeks, it travels to and is stored in bone and teeth. Symptoms associated with lead exposure include possible decrease in memory; weakness in the fingers, wrists, or ankles; and anemia. Children are more sensitive to the effects of lead than adults. Lead can cause premature birth, smaller babies, decreased intelligent quotient scores (IQ) and reduced post-natal growth. (Draft ATSDR Toxicological Profile for Lead).

ATSDR has not derived an MRL for lead. A reference dose (RfD) does not exist for lead because no thresholds have been demonstrated for the most sensitive effects in humans. The RfD is an estimate of daily human exposure to a contaminant for a lifetime below which health effects (non-cancer) are unlikely to occur. A quantitative estimate of lead carcinogenic risk from oral and inhalation exposure has not been determined. Quantifying the cancer risk for lead involves many uncertainties, some of which may be unique to lead. Age, health, nutritional state, body burden, and exposure duration influence the absorption, release, and excretion of lead.

Lead was found at 50 ppb in the on-site groundwater. The EPA's Action Level for lead in drinking water is 15 ppb. Because there is no known thresholds for the most sensitive effects in humans, adverse health effects in children could occur if residential wells become contaminated by migration of site contaminants. The wells were not contaminated with lead at the last monitoring date.

2-Methylnaphthalene

The short- and long-term health effects caused by exposure to 2-methylnaphthalene have not been studied. This substance is a solid at room temperature. It is used to make other chemicals that are used as pesticides. There is no information about the release of this chemical into the environment or what happens to this substance after it is released. (ATSDR Toxicological Profile for Naphthalene/2-Methylnaphthalene)

This chemical was found at 110 ppb in the on-site groundwater. There is currently no data on the effects of acute or chronic duration exposure to 2-methylnaphthalene in humans or animals. There is also no information on the carcinogenic potential of 2-methylnaphthalene in humans or animals. There are no regulations or advisories for this chemical at this time. This chemical is a potential contaminant of residential wells.

Naphthalene

Naphthalene is a white solid substance with the characteristic odor of tar or mothballs. It is released into the air from the burning of fuels such as coal and oil, and from the use of mothballs containing naphthalene. Naphthalene evaporates easily. When it is released into the air, humidity and sunlight cause it to break down within a few hours.

The primary health concern for humans exposed to naphthalene for either short or long periods of time is Hemolytic Anemia (a condition involving the breakdown of red blood cells). These effects can occur from either breathing or eating naphthalene. Cancer has not been seen in humans or animals exposed to naphthalene. (ATSDR Toxicological Profile for Naphthalene/2-Methylnaphthalene)

Naphthalene was found in the on-site groundwater at 110 ppb. The lifetime health advisory for this chemical is 20 ppb. The estimated daily ingestion of this chemical in drinking water is considerably less than the level of the lowest observed serious adverse health effects in humans and animals. This chemical is a potential contaminant of residential wells surrounding the NSL site.

Trichloroethylene

Trichloroethylene is a man-made chemical that does not occur naturally in the environment. It is mainly used as a solvent to remove grease from metal parts.

Trichloroethylene can easily enter the body through ingestion, inhalation, or dermal contact. This chemical is not likely to build up in the body. Exposure to high levels of trichloroethylene can cause dizziness, sleepiness, and damage to some of the nerves of the face. It has caused rashes in some individuals who were exposed dermally. It is not known if this chemical causes cancer or will affect human reproduction. (ATSDR Draft Toxicological Profile for Trichloroethylene)

The intermediate MRL for trichloroethylene is 100 g/kg/day, which assumes exposure for longer than 14 days, but less than 1 year. The estimated daily ingestion dose is considerably lower than the intermediate MRL. TCE was not found in the last sampling of the residential wells. This chemical is a potential contaminant of private residential wells.

B. Health Outcome Data Evaluation

As discussed in the Health Outcome Data subsection, cancer mortality data on Boone County, Indiana, and the United States are available by race, gender, and year (1950-1979). The cancer rates of Boone County were compared to Indiana and U.S. cancer rates. The organs that are affected by site related chemicals are the central nervous system, liver, lungs, heart, and kidneys. The cancer rates for Boone County for this system and organs are comparable to state and U.S. rates for all race/gender groups.

C. Community Health Concerns Evaluation

1. Are both the NSL and ECC sites being addressed for cleanup together or separately?

Cleanup for the NSL and ECC sites will be addressed separately.

2. Does the site present a public health hazard?

The site presently poses a health hazard to individuals who use private wells as their primary source of drinking water. Sodium was found in elevated levels in the off-site groundwater, and private well water. Long-term ingestion of high concentrations of sodium are believed to be associated with the development of hypertension and would complicate clinical treatment of hypertensive patients on salt-restricted diets.

3. What would be the long-term health effects of hazardous waste leachate?

Leachate from the Northside Landfill contains various chemicals including 4-methylphenol. This chemical is corrosive to all tissues and can cause serious burns. This chemical should be biodegraded, however, to some extent in the ground and should be degraded further by microorganisms upon exposure to open air. The ambient conditions in Finley Creek and the unnamed ditch would have to be just right for this chemical to be released in the air. To assess the long-term health effects of this leachate, an evaluation of the cancer data for Boone County was done. Results show that there has not been a significant increase of cancer in the past forty years.

4. How dangerous are the contaminants of concern at the site?

There are various toxic chemicals found on the site. The chemicals become dangerous when humans may be/are exposed through inhalation, ingestion, or dermal contact. Access to this site, however, is restricted. Currently, the only chemical that poses a health threat to the community is sodium, which was found during the residential well sampling.

5. What is the direction of groundwater flow at the site?

Regional groundwater flow is from the northeast to the southwest with a regional discharge at Eagle Creek.

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