PUBLIC HEALTH ASSESSMENT
ZIONSVILLE, BOONE COUNTY, INDIANA
The tables in this section list the contaminants of concern. We evaluate these chemicals in thesubsequent sections of this public health assessment and determine whether exposure to them haspublic health significance. ATSDR selects and discusses a chemical as a contaminant of concernbased upon the following factors:
- the chemical has no comparison value and/or may be toxic to humans at specified levels;
- the comparison of on-site and off-site concentrations with health assessment comparison values for (1) noncarcinogenic endpoints and (2) carcinogenic endpoints;
- an evaluation of the field data quality, laboratory data quality, and sample design; and
- community health concerns related to a particular chemical.
In the data tables that follow under the On-site Contamination and Off-site Contamination subsections, the listed chemical does not mean that it will cause adverse health effects fromexposures. Instead, the list indicates which chemicals will be evaluated further in the public health assessment.
Comparison values for this public health assessment are contaminant concentrations in specificmedia that are used to select contaminants for further evaluation. Sample data provided aredocumented in the Final RI report. Any data that is estimated or below its detection limit is notused in this report. Please note that all data used has been qualified under the Quality Assuranceand Quality Control section of this document.
|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. |
|=||Environmental Media Evaluation Guide. EMEGs are media-specific comparison values that are used to select contaminants of concern at hazardous waste sites. They are derived from the minimal risk level. |
|=||Lifetime Health Advisory (for drinking water). The LTHA is derived from the Drinking Water Equivalent Levels for noncarcinogens. For noncarcinogenic organic and inorganic compounds, LHAs are 20% and 10% respectively of the DWEL. For possible carcinogens, the LHA is divided by an additional factor of 10. |
|=||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. |
|=||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. |
|=||Parts per billion. |
|=||Reference Dose. EPA's estimate of the daily exposure to a contaminant that is unlikely to cause non-cancerous adverse health effects.|
The Toxic Chemical Release Inventory (TRI) is an EPA database that contains information onchemical releases of industries in the United States. It is used to determine the potential sourcesof contamination near NPL sites. A computer search was conducted of all available toxic releaseinventory (TRI 87-90) data to determine the number of industries near the site within the City ofZionsville (zipcode = 46077). The data did not show any industries with chemical releases inZionsville, Indiana during 1987 to 1991.
All chemicals found in sampled media have been assessed for adverse health effects and arelisted in the tables in Appendix B at the end of this public health assessment. These tables alsoinclude the depth of soil samples (depths have been rounded), the location of all samples, andeach chemical's sample concentration range.
Subsurface Soil/Soil Boring
In Phase I (May 1984), soil borings were made at 15 locations and surficial samples werecollected at 20 locations. Borings were not advanced more than 2½ feet below ground surfacebecause of rocks and other debris. Surficial samples were generally no deeper than 6 to 8 inchesbelow ground surface. The ATSDR definition of surface soil is samples taken at less than 3inches. Because the samples taken at this site are a composite of 0-8 inches, these surface soilsamples will be considered as subsurface.
Eleven borings were advanced in the north drum storage area to assess the depth andconcentration of VOCs. Four borings were also advanced on the perimeter of the concrete pad,which served as the south drum storage area. Twelve subsurface soil samples (AA through AL)were collected on the large embankment along the north and northwest sides of the site. Threesamples were collected in the polymer pit area (Pits N, DC, 6 and S). Three samples (AM-SW,AO-SE, and AP-SE) were also collected adjacent to the south concrete storage pad. One surfacecomposite sample (N of C) was collected from the drum storage area between the concrete pad and the lagoon.
No inorganic analyses were run on the samples collected in May.
In the Phase II (October 1984) soil sampling effort, nine soil borings were advanced through thesouth concrete pad to a maximum depth of 12½ feet (Figure 3, Appendix A). Intermediateboring depths ranged from 2 to 5 feet, while deep boring depths ranged from 5 to 9 feet.
Inorganic contamination of the soil is apparently greatest in the near surface (0-3 feet) soil innorthern portions of the site. This contamination extends to depths of at least 5 feet, although itis less widespread than observed in the overlying shallow soil.
Organic contaminants at the site are VOCs and phthalates. Organic contamination decreaseswith depth in the variety of compounds and their associated concentrations. They were detected,however, at the maximum depth of sample analysis (8½ feet).
A contaminant of concern was selected from Phase I or II based on the highest concentrationfound in either Phase. The contaminants of concern in the subsurface soil/soil borings are listedin Table 1.
Range - ppb
|aldrin (SB)||1||AN - B6||10-210||41||CREG|
|aroclor-1016 (PCB) (SS)||N/A||N of P||10,800||*|
|aroclor-1232 (PCB) (SS)||N/A||N of P||16,200||*|
|aroclor-1248 (PCB) (SS)||N/A||N of P||10,800||*|
|1,4-dichlorobenzene (SS)||0-1 (AO-SE only)||AO-SE & N of P||33,700-570,000||*|
|4,4-DDD (SB)||1-2||AE-AG & D7||1,080-5,900||2,900||CREG|
|4,4-DDT (SB)||1-2||An - D7||40-36,000||2,100||CREG|
|dimethyl phthalate (SB)||1||AE-AG||25,400||*|
|di-n-butyl phthalate (SS)|
|AD-SE - N of PD D7|
|di-n-octyl phthalate (SS)|
AE-AH - B6
|endosulfan sulfate (SS)|
|N of PD - N of P |
|endrin aldehyde (SB)||2||D7||20,000||*|
|gamma-BHC (lindane) (SS)|
|N of PD|
B6 - D7
|2-hexanone (SB)||2-4||SB-04 & SB-08||70-1,600||*|
|0-1 (AM-SW only)|
|AM-SW - N of P |
AE-AH - B6
|0-1 (AO-SE only)|
|AO-SE - N of P|
|0-1 (AM-SW only)|
|AM-SW - N of PD |
|0-1 (AO-SE only)|
|AO-SE - N of PD |
AE-AH - B6
|phenanthrene (SB)||1-2||AE-AH & D7||4,600-8,000||*|
|1-2||D7 - B6||6-8||*|
|AO-SE - AM-SW |
AE-AH - D7
|toxaphene (SS)||N/A||N of P||10,800||640||CREG|
|0-1 (AO-SE only)|
|AO-SE -N of P |
AN - B6
|0-1 (AL only)|
|AL - N of P|
AN - B6
SB-05 & SB-09
|SB-09 & SB-08|
SB-05 & SB-01
- * No comparison value available
Groundwater - Monitoring Wells
A three-phased groundwater sampling program was conducted at the ECC site. During the firstphase sampling effort, two on-site monitoring wells (MW-1A and MW-2A) were found to becovered with concrete and were inaccessible. During the phase two sampling effort, these twowells were again inaccessible. Additional monitoring wells were installed. All monitoring wellswere installed off-site, however, except monitoring well 8A (Figure 4, Appendix A). This wellwas installed in the shallow aquifer at a depth of approximately 30 feet. Chemicalcontamination in monitoring well 8A was detected during Phase III of the sampling program. Samples were analyzed for organic and inorganic chemicals.
Contaminants of concern in this on-site groundwater monitoring well are listed in Table 2.
Range - ppb
- * No comparison value available
Surface Water and Sediment
Surface water and sediment samples were collected in July 1983 from Finley Creek, EagleCreek, and an unnamed ditch east of the site.
The scope of the surface water and sediment sampling effort included the following: fivesurface water samples, one surface water duplicate sample, one surface water field blank, sixsediment samples, one sediment duplicate sample, and one sediment field blank. Surface watersample numbers included SW-001, -002, -003, -004-001, and duplicate sample 004-002 (Figure 5, Appendix A). Sediment sample numbers included SD-001, -002, -003, -004-001, duplicate-004-002, -005, and -006 (Figure 6, Appendix A).
Contaminants of concern in the off-site surface water and sediment samples are listed in Table 3.
|Chemical||Surface Water||Sediment||Comparison Value|
- * No comparison value available
A EPA Action Level
Groundwater - Residential Wells
The residential well sampling effort was performed in May 1983. The general well selectionstrategy was to select residential wells that would adequately characterize water quality in theshallow drinking water aquifer (40 feet or less) in the immediate vicinity of the site. Availablehydrogeologic information, well construction details and well logs were reviewed prior toselection of the residential wells sampled during this effort. The residential well sampling effortat the site included the following samples: five residential well samples ECC-RW003, RW006,and RW007 (downgradient of the site), RW004 (upgradient of the site), RW005 (west of thesite); one residential well duplicate sample (RW005-002); and one field blank (ECC-RW001-001). (Figure 7, Appendix A)
All wells were pumped for 20 to 30 minutes prior to sampling. Samples were collected at thefaucet closet to the wellhead, and upstream of any water conditioning devices (e.g., watersoftener, iron filter, etc.). Samples were collected by filling the sample bottles directly from thefaucet. Distilled water for the field blank sample was obtained from the ISDH.
Organic analysis of residential well water samples failed to detect any of the chemicals sampledfor. Contaminants of concern in the residential wells are listed in Table 4.
Range - ppb
Groundwater - Monitoring Wells
A three-phased groundwater sampling program was conducted during 1983 and 1984 at the ECCsite: (I) July 1983, (II) November 1983, (III) December 1984.
The scope of the Phase I effort at the site included the following: twelve groundwatermonitoring well samples, two groundwater duplicate samples, and one groundwater field blank. Monitoring well (MW) numbers included ECC-1A, 1C, 2A, 2B, 2C, 3A, 3C, 4A, 4C, 5A, 6A,7A, 9A, 10A, 11A; and MW-1A and MW-2A (Figure 4, Appendix A).
During the first phase sampling effort, only nine wells were sampled. One well (ECC-4A) wasnot sampled because of oil contamination.
The scope of the Phase II groundwater sampling effort included the following: 13 groundwatermonitoring well samples, two groundwater duplicate samples, and one groundwater field blank.
During the second phase of the sampling effort only 11 wells were sampled. The sampled wellsincluded the nine wells sampled in Phase I and two new wells (ECC-6A and ECC-7A) along theeastern boundary of the site. The well (ECC-4A) found to be contaminated during the firstphase sampling effort was not included in the scope of work for Phase II groundwater sampling.
The scope of the Phase III groundwater sampling effort included the following: ten groundwatermonitoring well samples, one groundwater duplicate sample, and one groundwater field blank.
During the third phase of the sampling effort, only the wells in the shallow aquifer weresampled. This included the six shallow wells sampled in Phase II and four wells installed inOctober and November 1984. Due to the slow recharge to the wells, only organic chemicalsamples were obtained from ECC-9A and ECC-11A.
Additional monitoring wells have been installed off-site as observed during the site visit thatwere not a part of the Final RI report.
The contaminants of concern in the groundwater monitoring wells are listed in Table 5.
- * No comparison value available
Two studies, a bioaccumulation study on freshwater mussels and a biological assessment ofstream ecosystems, have been performed in the vicinity of ECC.
In the first study, the ISDH suspended live freshwater mussels, (Lampsilis radiata siluoides) inwire baskets at four locations (two upstream and two downstream of the site) on April 24, 1981,(Figure 8, Appendix A). On June 9, 1981, mussels were taken out of the stream, wrapped insolvent-rinsed aluminum foil, and kept frozen until analyzed. Each sample consisted of fivemussels.
The second study was performed by the Department of Zoology at Depauw University from1978 to 1980 as part of a larger biological monitoring program of fish populations and benthicmacroinvertebrates. One of the areas studied was the Eagle Creek watershed, including FinleyCreek. Fish were collected using an electric seine. Samples were collected both upstream anddownstream (Figure 9, 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 the only contaminant found downstream at levels higher than upstream of the ECC site was arsenic.
Results of the biological monitoring program assessment of the fish population showed that thefish population downstream is smaller than upstream of the site. Samples taken downstream alsoconsistently ranked lower in density, biomass, or number of families than upstream samples.
Environmental Data Gaps
Due to the lack of off-site surface soil samples and ambient air monitoring, it is not possible tocharacterize the extent of contamination found in these media. It is also difficult to characterizethe site as the source of groundwater contamination, as only one on-site monitoring well isfunctional.
In preparing this public health assessment, the ISDH relies on the information provided in thereferenced documents and assumes that adequate quality assurance and quality control measureswere followed with regard to chain-of-custody, laboratory procedures, and data reporting. Thevalidity of the analysis and conclusions drawn from this public health assessment are determinedto be complete and comprehensive except for the following noted contaminations and detectionsof chemicals below quantification limits that were deemed unacceptable for use.
Sub-Surface Soil and Soil Borings
The laboratory was only able to estimate the levels of benzoic acid in the subsurface soil and soilboring samples. The chemicals di-n-butyl phthalate, beryllium, cobalt, and vanadium werefound below the laboratory quantifiable levels in the soil samples. These chemicals will not beevaluated further as contaminants of concern in this medium.
Groundwater - Monitoring Wells
Methylene chloride was found in nearly all samples and field blanks. It was used in preparatorycleaning of the vials used for the samples. Acetone also was found in numerous samples as wellas field blanks. Reagent grade acetone was used for equipment decontamination. Tetrachloroethene and trichloroethene were detected in wells 1A, 2A, and 5A at levels less thanthe laboratory quantification limit during the November 29-30 sampling events. Chrysene wasalso detected below the laboratory quantifiable limit. The values for the following chemicalswere estimates only: benzene, thallium, tin, vanadium and magnesium. The chemical 2-butanone was found in the associated laboratory blank and is considered a laboratorycontaminant.
Results indicate the reliability of the inorganic analysis to be strongly suspect and not considereduseable. Previous analysis of residential well samples did not find inorganic chemicalsexceeding water quality standards with the exception of one sample (RW005). Organiccontamination was not found in any residential wells although acetone was reported in onesample, which was likely introduced during sampling. Reagent grade acetone was used forequipment decontamination. It was found in numerous samples as well as field blanks. Qualityassurance data indicate that boron analyses are invalid because of contamination in thepreparation blank.
Surface Water and Sediment
Mercury was found at SW-003 and SW-004 though detection in the field blank indicates it to bea sampling or laboratory contaminant. Beryllium, methylene chloride, o-xylene, andtetrachloroethene were detected in surface water samples; however, concentrations were belowlaboratory quantifiable limits. Contamination of samples by methylene chloride is probably dueto sample bottle contamination. Bis(2-ethylhexyl)phthalate was also detected in the upstreamsample SW-002, but only in concentrations below the laboratory quantifiable limit.
As mentioned in the Site Visit subsection, the site is only accessible through the main entrance. Because methane gas is vented at Northside Sanitary Landfill (borders the ECC site on the eastside), the potential hazards from buildup of gas to explosive levels is limited. Possible physicalhazards present on-site are drums and two old buildings, which are in a deteriorating state. These buildings, however, are scheduled to be removed during the remediation of the site.
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 throughan environmental medium, a point of exposure, a route of human exposure, and an exposedpopulation.
ATSDR categorizes an exposure pathway as a completed or potential exposure pathway if theexposure pathway cannot be eliminated. Completed pathways require that the five elementsexist 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 fiveelements is missing, but could exist. Potential pathways indicate that exposure to a contaminantcould have occurred in the past, could be occurring now, or could occur in the future. Anexposure pathway can be eliminated if at least one of the five elements is missing and will neverbe present. We assume that all individuals working on-site follow the site specific health andsafety plan, thus they are not considered as exposed populations.
Table 6 identifies the completed exposure pathways, and Table 7 identifies the potentialexposure pathways. The discussion that follows these two tables incorporates only thosepathways that are important and relevant to the site. We also discuss some of those exposurepathways that have been eliminated.
Off-Site Groundwater/Residential Wells
Results of the hydrogeologic investigation have shown the existence of four hydrogeologic unitsin the area, a shallow saturated zone, a shallow sand and gravel aquifer, a clayey silt and siltyclay zone, and a deep confined aquifer. Possible groundwater contaminant sources at the ECCsite include the cooling water pond, and the surface storage areas and spill areas around the bulktanks. Migration of soil contaminants to the shallow saturated zone has occurred on-site asevidenced by high levels of contaminants in well 11A. Further leaching of soil contaminants tothe saturated zone is expected to be slowed due to the presence of a compacted silty-clay cap onthe northern half of the site, and the continued existence of the concrete pad on the south half ofthe site.
The shallow sand and gravel aquifer has been shown to be contaminated with inorganic andorganic chemicals in well 7A and lesser amounts of organics in wells 8A and 10A. Thegroundwater is locally confined in this aquifer with the hydrologic gradient being verticallyupward. Because of the close proximity of the NSL site east of ECC, it cannot be definitivelystated that the source of contamination in wells 3A and 7A is ECC, although the contaminantsare consistent with those found on-site. Organic contamination in wells 8A and 10A is likelydue to on-site soil at ECC since those wells are directly downgradient of ECC contaminated soiland not NSL.
Contamination of the shallow sand gravel aquifer may have occurred either via migrationthrough the silty clay till on-site, or through contaminated water and sediment in the formercooling water pond. The cooling pond intersects the shallow sand and gravel aquifer.
The residents surrounding the ECC site all use private residential wells for their water supply. Sampling data on these wells indicate a high sodium contamination in this water. Adversehealth effects could occur in individuals using private wells as their primary source of drinkingwater.
These private wells are also a potential pathway for residents to ingest, inhale, or be dermallyexposed to site-related organic chemicals, which were found in the off-site monitoring wells, butnot in the private wells. While these organic chemicals (Table 5) do not appear to have migratedto the residential wells, it must be assumed they have a potential of doing so because of thegroundwater flow migrating from northeast to southwest.
Groundwater flow beneath the site is, in general, toward the south and discharges into FinleyCreek. It flows in an easterly direction toward the unnamed ditch along the eastern edge of thesouthern half of the site.
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. Contaminationof the deep confined aquifer is unlikely because of the thick sequence of low permeability soilsthat act as a confining layer. Future migration of on-site contaminants to the deep aquifer ishighly unlikely also due to the upward vertical hydraulic gradient. The most probable pathwaysfor contaminant transport in the groundwater are through migration from the shallow saturatedzone 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 fortheir health effects in the Toxicological Evaluation subsection of this public health assessment.
|EXPOSURE PATHWAY ELEMENTS||TIME|
| POINT OF|
| ROUTE OF|
Off-Site Surface Soil/Dust Pathway
Although the ECC site was covered with a clay cap upon completion of surface cleanupactivities, samples from ponding surface water indicated the presence of organic chemicals. Theclay that was used to cap the ECC site was obtained from burrowed areas at NSL.
As part of the emergency response effort, one soil sample of the burrow material was analyzedfor volatile organic priority pollutants and heavy metals. Low levels of inorganic chemicalswere identified (below background concentrations) and extremely low levels of benzene, carbontetrachloride, ethylbenzene, and toluene were detected in samples of the cap material. Theconcentrations of these chemicals in the cap material were below health comparison values andare not of concern. Below the cap, heavily contaminated soil could be a risk to receptorpopulations since any future excavation might bring contaminants to the surface.
Transport of contaminants from on-site soils is also likely to occur through leaching. As waterinfiltrates through the contaminated soil, it will desorb many compounds and eventually leachinto the groundwater in the shallow saturated zone. This is presently the case as the groundwatersamples from the shallow saturated zone were found to be contaminated with VOCs.
Because of the protective cap and vegetation on-site, the exposure through surface soil would beminimal. Surface soil samples of less than 3 inches have not been taken. In seasonal dryconditions during past and present on-site activities, contaminated windblown dust could travelto neighboring residences. Routes of exposure to residents surrounding the ECC site areinhalation, incidental ingestion, and dermal contact.
The extent of off-site surface soil contamination due to on-site accumulation and unauthorizeddischarge of contaminated storage water, poor management of drum inventory, unapprovedburning of chlorinated hydrocarbons and other solvents, and several spills, is not known. Off-site surface soil sampling will be necessary to further evaluate this exposure pathway.
Off-Site Surface Water
A well-developed drainage pattern exists in the area surrounding the ECC site. The principalsurface drainage areas are Finley Creek and its associated tributary, and Eagle Creek. Twominor surface drainage areas are adjacent to the site. The site is located outside the 100-yearflood plain.
Natural surface water runoff from the area surrounding the site flows toward the unnamedtributary of Finley Creek, or toward Finley Creek. Surface water runoff from the northern partof the site largely flows south where a berm along the edge of the concrete pad redirects runoffwest to the ditch. Runoff from the concrete pad flows south and is routed through a pipe at thesoutheast corner of the site and to the unnamed ditch. Before capping, runoff was directed to thecooling pond and occasionally overflowed to the unnamed ditch.
Inorganic contamination of surface water does not appear to be occurring off-site in the vicinityof ECC. In the vicinity of ECC, inorganic sediment contamination is limited to lead in theunnamed ditch. Organic contamination of off-site surface water is limited to location SEW-004. ECC site records and chemical analysis data are consistent with the ECC site as the source of organic contaminants detected in location SW-004. Organic contamination ofsediments possibly resulting from the ECC site was found at SD-005 (bis[2-ethylhexyl]phthalate) in the unnamed ditch and SD-004 in Finley Creek (4-methylphenol).
Individuals wading or participating in recreational activities in Finley Creek could potentially beexposed by dermal contact and less significantly by inhalation to site-related chemicals found inthe off-site surface water. 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 amain source of contaminant exposure to humans.
Both the unnamed ditch and Finley Creek receive groundwater and surface water runoff fromthe ECC site. Contaminants in the surface water may volatilize, precipitate, or adsorb insediments, or remain in solution and be transported downstream to Big Eagle Creek andeventually the Eagle Creek Reservoir. Individuals may be exposed by wading in the creek,incidentally ingesting contaminated water, or ingesting aquatic life which have bioaccumulatedcontaminants.
Contaminants in stream sediment may dissociate and re-enter the surface water. Thecontaminants can then be re-suspended during high water flow and carried downstream. Duringlow water flow periods, contaminated sediments may be exposed along the stream banks andmay be transported as dust.
Aquatic Life Pathway
As mentioned in the sediment pathway, both the unnamed ditch and Finley Creek receivegroundwater and surface water runoff from the ECC site. Once contaminants enter the surfacewater, they will either volatilize, adsorb to sediment, or experience large dilutions beforereaching the Eagle Creek Reservoir.
Mussels are bottom dwellers and feeders; therefore, they are likely to bioaccumulatecontaminants found on sediments or in surface water. The levels of contaminants found in thebioaccumulation study in mussels may be indicative of the levels of contamination found inother aquatic life in Finley Creek.
Analysis results for contaminants found in mussels included lead, mercury, and arsenic. Leadand mercury were detected at levels below the Food and Drug Administration permissible levels. Arsenic was the only contaminant found downstream at levels higher than upstream. PCBs,dieldrin, and chlordane were not detected in the sample analysis. Individuals could be exposedindirectly to site-related contaminants by eating aquatic life caught in Finley Creek.
|EXPOSURE PATHWAY ELEMENTS||TIME|
| POINT OF|
| ROUTE OF|
|Aquatic life||ECC||Aquatic life||Finley Creek||Ingestion||Residents||Past|
|ECC||Surface Water||Finley Creek||Ingestion,|
surrounding ECC site
In this section 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 communityhealth concerns.
This subsection of the public health assessment assesses the public health implication ofcontaminants that are associated with an exposure pathway that have not been eliminated in thePATHWAYS ANALYSES section.
ATSDR has developed toxicological profiles on several chemicals that have been found at thissite. These profiles provide information on health effects, environmental transport, humanexposure, and regulatory status.
Sodium was the only chemical measured in drinking water wells above its comparison value. Therefore, possible adverse health effects from ingestion of the maximum concentration ofsodium will be discussed later. A toxicological profile for sodium has been provided belowalong with a toxicological profile for each of the contaminants of concern found in the on-sitegroundwater.
Calcium, cobalt, iron, magnesium, and potassium are considered to be essential human nutrients. They can, however, exhibit toxic properties at high levels of exposure. The levels of thesechemicals in the groundwater would not pose any health concern.
Aluminum is not considered a contaminant of concern in the soil as it is one of the mostcommon natural constituents of soil; and, because it was found at levels much lower than theaverage adult daily intake, as well as lower than the levels normally found in soil in the easternUnited States.
The concentrations of aluminum in off-site groundwater, however, could cause adverse healtheffects to individuals using: (1) existing residential wells in the future should they becomecontaminated at comparable levels, or (2) any newly installed residential wells. If personsshould install a well into the contamination zone containing the maximum concentrations ofaluminum, these persons could be exposed to an estimated dose greater than the EPA proposedSecondary Maximum Contaminant Level for drinking water (.05 ppm), but considerably lowerthan the level at which adverse health effects have been observed in research. (ATSDR Toxicological Profile for Aluminum).
It is important to note, however, that aluminum has not been shown to cause cancer in animals. Also, when aluminum is taken orally, very little goes from the stomach into the bloodstream. Most aluminum leaves the body quickly in the feces. The small amount that does enter thebloodstream leaves in the urine. This chemical is a potential contaminant of residential wells.
Long-term ingestion of high concentrations of sodium are believed to be associated with thedevelopment of hypertension and would complicate clinical treatment of hypertensive patientson salt-restricted intakes. Because intake restrictions of sodium are often part of hypertensivetherapy, the levels of sodium in the off-site residential wells could represent a significant healthconcern to residents who use private wells as their primary source of drinking water.
Typically, prescribed low-sodium diets attempt to limit sodium intake from food and water toeither 2.0, 1.0, or 5.0 grams (g) in a 24-hour period. It has been suggested by the NationalAcademy of Sciences (NAS) that, where water supplies contain more than 20 ppm, dietaryrestriction to less than 1.0 g is difficult to achieve and maintain. (NAS 1977)
Antimony is a soft metal insoluble in water and organic solvents. It was found in off-sitegroundwater at 4 ppb. This chemical was not found in the residential wells. Antimony isprimarily considered a skin irritant. The RfD for antimony is 0.4 µg/kg/day. The levels ofantimony typically found in soil in the eastern United States, however, is 9,000 ppb. Adversehealth effects are not expected from exposure to this chemical at the specified levels. (Sittig.Handbook of Toxic & Hazardous Chemicals)
Chloroethane is also called ethyl chloride. Most chloroethane released into the environmentends up as a gas in the atmosphere, but small amounts may enter groundwater as a result offiltration through soil. Once in the atmosphere, chloroethane breaks down fairly quick byreacting with substances in the air.
Chloroethane will most often enter the body through inhalation, although it may also enter thebody through contaminated drinking water. It is not known if chloroethane produces cancer inhumans. There is no oral chronic Minimal Risk Level (MRL) for this chemical but there is anintermediate inhalation MRL. Unfortunately, air monitoring has not been done for this site, thusan estimated daily inhalation dose exposure cannot be calculated. The MRLs are estimates oflevels posing minimal health risk to humans. They include adjustments to reflect humanvariability and extrapolation of data from laboratory animals to humans. (ATSDR ToxicologicalProfile for Chloroethane)
Chloroethane was found at 120 ppb in the off-site groundwater. The possible routes of exposureare 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 potentialcontaminant of private wells surrounding the ECC site.
Chloromethane is a naturally occurring chemical that is made in large amounts in the oceans andis produced by some plants and rotting wood, and when materials such as grass, wood, charcoal,and coal are burned. Since chloromethane is continuously released into the atmosphere fromoceans and biomass, a very low concentration will always be present.
The health effects resulting from short- or long-term exposure of humans to water containingspecific levels of chloromethane are not known. (ATSDR Toxicological Profile forChloromethane)
Chloromethane was found in off-site groundwater at 100 ppb. A chronic health guideline foringestion of this chemical, such as an MRL, has not been determined. There is a chronicinhalation MRL of chloromethane. An estimated daily inhalation dose cannot be calculatedbecause of the lack of air monitoring data for this site. Based on the sampling data, there iscurrently no one exposed to this chemical through the residential private wells.
The chemical 1,1-dichloroethane is a manmade liquid. It evaporates quickly at roomtemperature and has an odor like ether. It is used to remove grease, and to dissolve othersubstances such as paint, varnish, and finish removers. (ATSDR Toxicological Profile for 1,1-Dichloroethane)
This chemical was found in the off-site groundwater at 96 ppb. It was selected as a contaminantof concern because reliable information on how this chemical affects human health is notavailable. There are no regulatory standards or advisories for 1,1-dichloroethane. It is importantto note that this chemical is only a potential contaminant of residential wells near the ECC site. No one is currently exposed to this chemical.
Trichloroethylene, or TCE, is a manmade chemical that does not occur naturally in theenvironment. It is mainly used as a solvent to remove grease from metal parts.
TCE can easily enter the body through ingestion, inhalation, or dermal contact. This chemical isnot likely to build up in the body. Exposure to high levels of trichloroethylene can causedizziness, sleepiness, and damage to some of the nerves of the face. It has caused rashes in someindividuals who were exposed dermally. It is not known if this chemical causes cancer or willaffect human reproduction. (ATSDR Draft Toxicological Profile for Trichloroethylene)
The intermediate MRL for trichloroethylene is 100 µg/kg/day, which assumes exposure forlonger than 14 days, but less than 1 year. The estimated daily ingestion dose is considerablylower than the intermediate MRL. TCE was not found in the last sampling of the residentialwells. This chemical is a potential contaminant of private residential wells.
Almost all vinyl chloride is manmade. Most of the vinyl chloride produced in the United Statesis used to make polyvinyl chloride (PVC). PVC is used to make a variety of plastic productsincluding pipes, wire and cable coatings, and packaging materials. (ATSDR Toxicological Profile for Vinyl Chloride)
Exposure to vinyl chloride is most likely to occur by inhalation. Vinyl chloride does not enterthe body by passing through the skin. Most of the vinyl chloride is gone from the body a dayafter it has been inhaled or swallowed. The liver, however, makes some new substances that donot leave the body as rapidly. A few of these substances are more harmful than vinyl chloridebecause they react with chemicals inside of the body and interfere with the way the body uses orresponds to these chemicals. It takes more time for the body to get rid of these changedchemicals, but eventually the body will remove them as well.
Based on animal and human studies, it has been determined that vinyl chloride is a knownhuman carcinogen. Studies of long-term exposure in animals show that increases in cancer mayoccur at very low levels of vinyl chloride in the air.
Vinyl chloride was found in the off-site groundwater at 86 ppb. An estimated daily ingestiondose was calculated. The results were much higher than the chronic oral MRL for this chemical. At this level of exposure cancer has been observed in humans; however, no one is presentlyexposed to this chemical at the specified levels.
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. The cancer rates ofBoone County were compared to Indiana and U.S. cancer rates (1950-1979). The organs thatare affected by site-related chemicals are the central nervous system, liver, lungs, heart, andkidneys. The cancer rates for Boone County for this system and these organs are comparable tostate and U.S. rates for all race/gender groups.
- How about toluene, methyl ethyl ketone, trichloroethene, or something of that nature; do you see those at the site?
These three chemicals were found in the on-site surface soil and soil borings. Trichloroethene, or TCE, was the only one of the three chemicals found in the on-site groundwater. This chemical was not found in the residential wells, but it wasfound in the off-site groundwater monitoring wells. It is important to note,however, that there is no population currently exposed to this chemical except forremedial workers.
- What is the depth of contamination at the site?
Soil borings were taken up to 12½ feet below the on-site surface soil. The lowestlevel at which contamination was found was 9 feet. The primary contaminantsfound at this level were inorganic chemicals.
In 1985 the entire site was capped and seeded. Below the cap, heavilycontaminated soil could be a risk to receptor populations since any futureexcavation might bring contaminants to the surface.
Transport of contaminants from on-site soils is also likely through leaching. Aswater infiltrates through the contaminated soil, it will desorb many compoundsand eventually leach into the groundwater in the shallow saturated zone. This ispresently the case as the groundwater samples from the shallow saturated zonewere found to be contaminated with volatile organic chemicals.
Because of the protective cap and vegetation on-site, the exposure tocontaminants found in the subsurface or surface soil would be minimal. There isa potential, however, for individuals to be exposed to these contaminants throughcontaminated groundwater.