PUBLIC HEALTH ASSESSMENT
NORTHSIDE SANITARY LANDFILL
ZIONSVILLE, BOONE COUNTY, INDIANA
The tables in this section list the contaminants of concern. We evaluatethese chemicals in the subsequent sections of this public health assessmentand determine whether exposure to them has public health significance.ATSDR selects and discusses a chemical as a contaminant of concern basedupon the following factors:
- the chemical has no comparison value and/or may be toxic to humans at specifiedlevels;
- the comparison of on-site and off-site concentrations with health assessmentcomparison values for (1) noncarcinogenic endpoints and (2) carcinogenicendpoints;
- an evaluation of the field data quality, laboratory data quality, and sampledesign;
- community health concerns related to a particular chemical.
Comparison values for this public health assessment are contaminantconcentrations in specific media that are used to select contaminants forfurther evaluation. Sample data provided are documented in the Final RIreport.
|CREG||=||Cancer Risk Evaluation Guide. CREGs are estimated contaminantconcentrations based on a one excess cancer in a million persons exposedover a lifetime. They are calculated from EPA's cancer slope factors.|
|LTHA||=||Lifetime Health Advisory (for drinking water). The LTHAis derived from the Drinking Water Equivalent Levels for noncarcinogens.For noncarcinogenic organic and inorganic compounds, LTHAs are 20% and10% respectively of the DWEL. For possible carcinogens, the LTHA is dividedby an additional factor of 10.|
|MCL||=||Maximum Contaminant Level (for drinking water). MCLs representcontaminant concentrations that EPA deems protective of public health (consideringthe 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 bythe NAS, that where water supplies contain more than 20 ppm, dietary restrictionto 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 containsinformation on chemical releases of industries in the United States. Itis 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 withinthe City of Zionsville (zipcode = 46077). The data did not show any industrieswith chemical releases in Zionsville, Indiana, during 1987 to 1991.
All chemicals found in sampled media have been assessed for adversehealth effects and are listed in the tables in the appendices at the endof this public health assessment. These tables also include the depth ofsoil samples, the location of all samples, and each chemical's sample concentrationrange.
Surface Soil - Phase I
On-site surface soil samples listed in the RI report were collectedin December 1984. All samples were collected at a depth of 2 inches (seeFigure 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. Twosamples, NSL-SL020-01 and SL021-01, were collected from the southwest sideof the landfill. Contamination was detected in the surface soils at onelocation, remote from the landfill, where the owner allegedly sprayed leachatepumped from the leachate collection tanks. Two organic chemicals, acetoneand methylene chloride, were found in samples SL020-01 and SL02201. Theyare not considered contaminants of concern because of the low levels foundand/or laboratory contamination of the samples.
Inorganic chemicals were detected in the surface soil samples. Aluminumis not considered a contaminant of concern as it is one of the most commonnatural constituents of soil, and because it was found at levels much lowerthat the average adult daily intake, as well as lower than the levels normallyfound in eastern United States soil.
Calcium, copper, magnesium, and potassium are considered to be essentialhuman nutrients and are generally not believed to be toxic. These fourinorganic chemicals are not considered to be contaminants of concern inthis or any other medium sampled from this site.
The contaminants of concern in the on-site surface soil are listed inTable 1.
Table 1. Contaminants of Concern in On-Site Surface Soil Samples,Phase I.
Range - ppb
- * No comparison value available
The hydrogeologic investigation which included subsurface soil samplingwas conducted at the NSL site from December 1984 through January 1985.A total of 39 subsurface samples were collected from 11 boreholes. Sampledepth 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 roundedto the nearest whole number. (EPA Remedial Investigation Report)
Fifteen monitoring wells were proposed for installation at locationsalong the perimeter of the NSL site (Figure 3, Appendix A). Eleven of the15 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 alsois a shallow borehole.
The area of greatest contamination in the sand and gravel water-bearingunits was southwest of the landfill at NSL12 and NSL13.
Subsurface soils in the glacial till showed contamination at all samplinglocations. The greatest contamination in glacial till subsurface soil wasin the southwest corner of the site, at NSL13, NSL12, NSL14, and NSL8S,and on the east side of the landfill at NSL11S. Lesser concentrations ofcontaminants 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.
- * No comparison value available
Glacial till is a mixture of clays, silts, sand, and gravel, and existsaround the NSL site from the surface or just below the loess to depthsup to 40 feet. A layer of sand and gravel exists at the NSL site belowthe glacial till and ranges in thickness from approximately 2 to 23 feet.
No strata below the sand and gravel were studied in the RI. Resultsfrom the ECC RI, however, suggest that the following strata exist at theNSL site:
|Lower Glacial Till||-||Glacial till consisting of very hard, silty clays approximately 120feet thick.|
|Lower Sand & Gravel||-||A sand and gravel layer about 15 feet thick at a depth of about 150to 165 feet below surface grade.|
The wells were installed in four well nests consisting of two wellsper nest. Each nest consisted of a shallow well screened in the first groundwaterencountered, and a deeper well screened in the first coarse-grained, water-bearingunit. Four other shallow wells were installed in proximity to deeper historicalmonitoring wells. Shallow wells ranged from 11.5 feet to 24.5 feet, anddeep wells ranged from 31 to 39.5 feet below surface grade.
In February and April 1985 the following samples were collected: 19samples from new and existing monitoring wells, one soil boring piezometersample (SBP), two groundwater duplicate samples, two groundwater fieldblank samples, and one matrix spike duplicate sample (Figure 3, Appendix A). A total of 51 monitoring wells and SBPs have been installed at theNSL site. The wells samples consisted of seven existing monitoring wells(MW1 through MW7), two SBPs (65 and 77), and 14 RI monitoring wells fora 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 theorganic analysis and metals fraction of the inorganic analysis was collectedfrom monitoring well NSL10S. Monitoring wells NSL8S and NSL8D were notsampled because they had been destroyed by a landfill vehicle in February1985. In April 1985 EPA returned to the NSL site to sample monitoring wellsNSL8SA and NSL8DA, which replaced the two demolished wells. Two monitoringwell samples and one groundwater field blank sample were collected. A secondeffort was made to sample SBP77, but due to its slow recharge, samplingwas unsuccessful. In May 1985 Phase II groundwater samples were collectedconcurrent with the Phase II surface water, bottom sediment, and residentialwell water samples. Samples were collected within the glacial till andthe sand and gravel water bearing units (Figure 3, Appendix A).
The 23 monitoring wells sampled during this effort were selected bythe EPA and its contractor, and the ISDH. The wells sampled consisted ofseven existing monitoring wells, MW1 through MW7 (sand and gravel waterbearing units), installed in December 1979; two SBPs, SBP65 and SBP77 (sandand gravel water bearing units), installed in 1982; and 14 RI monitoringwells (glacial till, and sand and gravel water bearing units), installedin December 1984 and January 1985.
Contamination was found in the glacial till groundwater on all sidesof 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 cornerof the NSL site. Lower levels of contamination were found in the sand andgravel water-bearing unit along the south side of the site.
All chemicals detected during the Phase I and II sampling are listedin Appendix B. The highest chemical concentration found in either PhaseI 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 arelisted in Table 3.
|Chemical||Glacial Till Water Bearing Zone||Sand & Gravel Water Bearing Zone||Comparison Value|
Range - ppb
Range - ppb
- * - No comparison value available
1 - Classified as a known human carcinogen by the NationalToxicology 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 leachatesamples were collected on the east side of the NSL site at the dischargepoint of a culvert located under the landfill roadway, approximately 460feet west of monitoring well MW5. Two liquid leachate samples were collectedfrom the drainage ditch constructed by the landfill owner. The third leachatesediment sample was collected at the surface of the southwest corner ofthe landfill, north of monitoring well MW2.
Leachate sediment samples collected on all sides of the landfill showedcontamination. The sample from the southwest portion of the site revealedthe highest contamination, including pesticides. Minimal contaminationwas found in leachate liquid.
A background soil sample was collected at the northeast side of NSLand is identified as NSL-SL028-01. The sample was collected approximately125 feet north of the landfill road along the fence and tree line.
The contaminants of concern in the liquid and solid leachate samplesare listed in Table 4.
|Chemical||Leachate Liquid||Leachate Solid||Comparison Value|
Range - ppb
Range - ppb
- * - 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 withthe Phase II groundwater, surface water, and bottom sediment sampling investigation.
Prior to collecting samples, existing wells in the vicinity of the NSLsite were inventoried. In April 1985 a door-to-door survey of the residentialhomes south and southwest of the site was conducted in order to gatherinformation regarding their wells.
Well locations were determined, and when possible, the depth of thewell was obtained either through knowledge of the owner or from availablerecords.
From the survey it was determined that most of the homeowners only knewthe approximate depth of their wells; therefore, a file search at the ISDHwas conducted. Well logs for wells within a 1-mile radius of the NSL sitewere 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 (122feet), and NSL-RW007-01 (blank).
Sodium was the only contaminant of concern found in private wells (Table 5).
Range - ppb
Surface Water and Bottom Sediment
In December 1984 (Phase I) and May 1985 (Phase II), surface water andsediment samples were collected from eight locations in Finley Creek andthe unnamed ditch (Figure 4, Appendix A). It was discovered that the landfillowner re-channeled Finley Creek to a location farther south of the NSLsite in 1980. Sample NSL-SW/SD004-01 was collected in this former sectionof the creek.
Ten surface water and ten sediment samples, including two duplicateand field blank samples, were collected from downstream to upstream. Surfacewater samples were collected from the center of the creek or ditch, andprior to the collection of the sediment samples to avoid sediment finesin the water samples. A bottom sediment sample was collected at each surfacewater sample location in an area along the bank where there was evidenceof sediment deposits along the creek or ditch bank, or below the surfacewater sampling point.
Sample locations for both phases were as follows: one sample upstreamof the site in Finley Creek, one sample upstream of the site in the unnamedditch, four samples in Finley Creek adjacent to the landfill, one samplebetween the former ECC and the landfill in the unnamed ditch, and one sampledownstream of the site and the confluence of Finley Creek. Phase II sampleswere collected in the same general area as Phase I, except for NSL-SW/SD0011-02.
The greatest number and highest concentrations of contaminants foundin surface water and sediments were detected at sampling point SD008/SD009,downstream of the confluence of the unnamed ditch and Finley Creek. Abovethe confluence, sediments showed contamination in Finley Creek at SD006and 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 ofthe landfill). The pesticide dieldrin was detected at SD011 in Finley Creekin the southeast portion of the site.
The contaminants of concern in the Phase I and II surface water andsediment samples are listed in Table 6.
|Chemical||Surface Water||Sediment||Comparison Value|
Range - ppb
Range - ppb
|Organic Chemicals, Phase I|
|Inorganic Chemicals, Phase I|
|Organic Chemicals, Phase II|
|Inorganic Chemicals, Phase II|
* No comparison value available
Two studies, a bioaccumulation study on freshwater mussels and a biologicalassessment of stream ecosystems, have been performed in the vicinity ofNSL.
In the first study, the ISDH suspended live freshwater mussels, (Lampsilisradiata siluoides) in wire baskets at four locations (two upstreamand 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-rinsedaluminum foil, and kept frozen until analyzed. Each sample consisted offive mussels.
The second study was performed by the Department of Zoology, DepauwUniversity, from 1978 to 1980 as part of a larger biological monitoringprogram of fish populations and benthic macroinvertebrates. One of theareas studied was the Eagle Creek watershed, including Finley Creek. Fishwere collected using an electric seine. Samples were collected both upstreamand downstream (Figure 7, Appendix A). Sampling normally took place oncea month in May, June, July, August, and October in 1978, 1979 and 1980.
Results from the mussel bioaccumulation study showed that arsenic wasthe only contaminant found downstream at levels higher than upstream ofthe NSL site.
Results of the biological monitoring program assessment of fish populationreported that the fish population is much less downstream of the site thanupstream. 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 thesetwo media.
In preparing this health assessment, the ISDH relies on the informationprovided in the referenced documents and assumes that adequate qualityassurance 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 phthalateswere detected in the laboratory and field blanks and may be laboratoryand/or field contaminants.
The surface water samples contained phthalates, acetone, and methylenechloride, which were detected in several samples, but were also detectedin field blanks and are considered likely laboratory or field contaminants.Mercury was detected in a number of samples but was also detected in thefield 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 fieldsamples and in the laboratory or field blanks, limiting the use of thisdata. Butyl benzyl phthalate, pyrene, and di-n-butyl phthalate were alsoidentified in the field samples and in the laboratory blanks, limitingthe use of the data.
Acetone, 2-butanone, and methylene chloride were identified in the on-sitegroundwater, and in the laboratory blanks limiting the use of this data.Di-n-butyl phthalate was also detected in the laboratory and field blanksthus 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 thanthe 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 laboratoryblank and are considered to be present due to laboratory possible/probablecontamination.
The values for 2-butanone and phenol were estimated and, therefore,are considered not valid or usable.
The on-site leachate contains chemicals which could cause burns uponcontact. Another threat or hazard from the site is exposure of site workersto uncovered garbage. The cap on the top of the landfill mound has forthe most part eroded, exposing domestic garbage. The garbage poses a fallor trip hazard where in an individual could fall landing on sharp edgesresulting in cuts and abrasions. The remediation of the site includes soil\gasventing. Venting mechanisms are already in place; therefore, hazards frombuild up of gas to explosive levels is limited.
To determine whether nearby residents are exposed to contaminants migratingfrom the site, ATSDR evaluates the environmental and human components thatlead to human exposure. This pathways analysis consists of five elements:a source of contamination, transport through an environmental medium, apoint of exposure, a route of human exposure, and an exposed population.
ATSDR categorizes an exposure pathway as a completed or potential exposurepathway if the exposure pathway cannot be eliminated. Completed pathwaysrequire that the five elements exist and indicate that exposure to a contaminanthas occurred in the past, is currently occurring, or will occur in thefuture. Potential pathways, however, require that at least one of the fiveelements is missing, but could exist. Potential pathways indicate thatexposure to a contaminant could have occurred in the past, could be occurringnow, or could occur in the future. An exposure pathway can be eliminatedif 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 specifichealth and safety plan, thus they are not considered as exposed populations.
Table 7 identifies the completed exposure pathways, and Table 8 identifiesthe potential exposure pathways. The discussion that follows these twotables incorporates only those pathways that are important and relevantto the site. We also discuss some of those exposure pathways that havebeen eliminated.
Off-Site Groundwater - Private Wells
Results of the hydrogeologic investigation have shown the existenceof four hydrogeologic units in the area, a shallow saturated zone, a shallowsand and gravel aquifer, a clayey silt and silty clay zone, and a deepconfined aquifer. Possible groundwater contaminant sources at the NSL siteinclude solid and liquid leachate, and the contaminated sub-surface soil.Migration of soil contaminants to the shallow saturated zone has occurredon-site as evidenced by high levels of contaminants in well NSL16. Furtherleaching of soil contaminants to the saturated zone is expected to be sloweddue to the presence of a compacted silty-clay cap on the entire site. Contaminationof the shallow sand gravel aquifer may have occurred, however, by migrationthrough the silty clay.
The residents surrounding the NSL site all use private residential wellsfor their water supply. Sampling data of these wells indicate a high, possiblysite related sodium contamination in this water. High levels of sodiumwere also found in the on-site groundwater and liquid leachate samplesindicating the site as the possible source of sodium. Adverse health effectscould occur in individuals using private wells as their primary sourcefor drinking water. Inhalation and dermal contact are not exposure routesfor 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 chemicalswhich were found in the on-site monitoring wells but not in the privatewells. If the groundwater in either the glacial till or sand and gravelwater-bearing units is consumed as a potable water supply in either a residential,commercial, or industrial setting, there is a potential for adverse healtheffects including cancer.
While organic chemicals do not appear to have migrated to the residentialwells, it must be assumed they have a potential of doing so because ofthe groundwater flow migrating from northeast to southwest. Migration ofcontaminants to the nearest residential wells surrounding the site is notindicated, 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 thicksequence of low permeability soils that act as a confining layer. Futuremigration of on-site contaminants to the deep aquifer is highly unlikelydue to the upward vertical hydraulic gradient. The most probable pathwaysfor contaminant transport in the groundwater are through migration fromthe shallow saturated zone or from the shallow sand and gravel aquiferto the unnamed ditch or Finley Creek.
All chemicals found in the off-site groundwater at levels of healthconcern will be evaluated for their health effects in the Toxicological Evaluation subsection of this public health assessment.
|EXPOSURE PATHWAY ELEMENTS||TIME|
|POINT OF |
|ROUTE OF |
|Ingestion||Child and adult|
High concentrations of contaminants were not found in leachate liquids.The presence of contaminants in leachate sediments, however, indicatesthat past discharges of contaminants from NSL have occurred, and couldrecur in the future.
Based on surface drainage patterns, only the contamination south ofthe landfill can be attributed exclusively to releases from NSL. Contaminationin the unnamed ditch and downstream of the confluence with Finley Creekcould 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 adversehealth 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 FinleyCreek at higher than upstream concentrations indicates that contaminants are presently being released to the unnamedditch.
The location of the westward-trending gully beneath the NSL and the presence of contaminants in the surface water inthe unnamed ditch and the groundwater in the southwest side of the landfill indicates that the gully may be a conduitfor contaminants migrating from the landfill. The portions of the old Finley Creek overlain by the south side of theNSL 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 betransported downstream to Big Eagle Creek and eventually the Eagle Creek Reservoir. Individuals may be exposedby wading in the creek, incidentally ingesting contaminated water during recreational activities, or ingesting fishwhich 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 sedimentsmay 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 recreationalactivities, and they could potentially be exposed by dermal contact and less significantly by inhalation to site relatedchemicals found in the off-site stream sediment. It is important to note, however, that because the exposure to siterelated chemicals would not be for an extended period of time, this medium is not considered a main source ofcontaminant exposure to humans.
Because of the protective cap and vegetation on-site, the exposure through surface soil would be minimal. Surfacesoil samples of less than 3 inches have been taken. In seasonal dry conditions during pass and present on-siteactivities, contaminated windblown dust could travel to neighboring residences. As noted during the site visit, thereare areas of exposed garbage on top of the landfill. Routes of exposure to residents surrounding the NSL site areinhalation, 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 thisexposure pathway.
As mentioned in the sediment pathway, both the unnamed ditch and Finley Creek receive groundwater and surfacewater runoff from the NSL site. Once contaminants enter the surface water, they will either volatilize or absorb tosediment, 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 sedimentsor in surface water. The levels of contaminants found in the bioaccumulation study in mussels may be indicative ofthe 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 exposedindirectly to site related contaminants by eating fish caught in Finley Creek. To adequately characterize the extent offish contamination in Finley Creek, additional fish sampling is needed.
| PATHWAY |
|EXPOSURE PATHWAY ELEMENTS||TIME|
|SOURCE|| ENVIRONMENTAL |
| POINT OF |
|ROUTE OF |
|Leachate||Northside Landfill||Leachate||Finley Creek, Unnamed Ditch||Ingestion, |
|Resident||Past Present |
|Surface Water & Sediment||Northside Landfill||Water||Finley Creek, Unnamed Ditch|| Incidental |
Ingestion, Inhalation, Dermal Contact
|Residents|| Past |
|Surface Soil||Northside Landfill||Soil||Yards|| Ingestion, |
|Residents|| Past |
|Fish|| Northside |
|Fish||Finley Creek||Ingestion||Residents who eat fish||Past Present Future|
In this subsection we will discuss the health effects of persons exposed to specific chemicals, evaluate state and localhealth data bases, if available, and address any existing community health concerns.
ATSDR has developed toxicological profiles on several chemicals that have been found at this site. These profilesprovide 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 healtheffects from ingestion of the maximum concentrations for sodium will be discussed later. A toxicological profile forsodium has been provided below along with a toxicological profile for each of the contaminants of concern found inthe off-site groundwater, although off-site groundwater is at present not a completed pathway.
Long-term ingestion of high concentrations of sodium are believed to be associated with the development ofhypertension and would complicate clinical treatment of hypertensive patients on salt-restricted intakes. Sodium wasfound 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-sitegroundwater 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 containmore than 20 ppm, dietary restriction to less than 1 g is difficult to achieve and maintain. (NAS, Drinking Water andHealth)
Inorganic arsenic has been determined to be a cancer-causing agent. The single most characteristic effect of long-termoral exposure to inorganic arsenic is a pattern of skin changes. This includes a darkening of the skin and theappearance of small "corns" or "warts" on the palms, soles, and torso. While these skin changes are not considered tobe a health concern, a small number of the corns may ultimately develop into skin cancer. (ATSDR DraftToxicological Profile for Arsenic)
Despite all the adverse health effects associated with inorganic arsenic exposure, there is some evidence that a smallamount of arsenic in the normal diet (0.01- 0.05 ppm) may be beneficial to your health. Arsenic levels found here arehigher than the EPA chronic oral RfD for this chemical. Possible health effects associated with the ingestion of thelevels of arsenic found here are irritation of the stomach and intestines with symptoms such as pain, nausea, vomitingand diarrhea. This chemical is currently only a potential contaminant of residential wells.
Benzene is a naturally-occurring substance produced by forest fires and is present in many plants and animals, butbenzene is also a major industrial chemical made from coal and oil. How benzene affects health depends on the leveland 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 wascalculated. The value was considerably lower than 5 ppb, the maximum contaminant level in drinking water for thischemical. Benzene is a proven cancer-causing agent in humans. Based on the estimated daily ingestion dose, there isno apparent risk of cancer increase due to the exposure of this chemical at the specified levels. This chemical iscurrently only a potential contaminant of residential wells.
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 bodyfrom food, water, or air is taken up into the blood from the lungs and intestines. Small amounts may also enter thebody by skin contact.
Most of what is known about the health effects of DEHP comes from animal studies, especially studies of rats andmice. Because DEHP appears to affect rats and mice differently than humans and other animals, it is difficult topredict the health effects in humans using information from animal studies. There have been no studies of workersexposed 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 movevery far away from where it was released. It dissolves very slowly in water. DEHP does not evaporate easily, andthus very little will be present in the air even near sources of production. An estimated daily exposure dose wascalculated. The value was much less than the chronic oral RFD for this chemical. At present this chemical is only apotential contaminant of the residential wells.
Chloroethane, which is also called ethyl chloride, is a manmade compound. Human activities are responsible foralmost all the chloroethane released into the environment. Most chloroethane released into the environment ends upas a gas in the atmosphere, but small amounts may enter groundwater as a result of filtration through soil. Once in theatmosphere, 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 throughcontaminated drinking water. It is not known if chloroethane produces cancer in humans. There is currently no oralchronic Minimal Risk Level (MRL) for this chemical but, there is an intermediate inhalation MRL. The MRLs areestimates of levels posing minimal health risk to humans. They include adjustments to reflect human variability andextrapolation of data from laboratory animals to humans (ATSDR Toxicological Profile for Chloroethane). Airmonitoring has not been done for this site, unfortunately, thus an estimated daily inhalation dose exposure cannot becalculated.
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 towater 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 is found in the earth's crust as a naturally occurring metal. Due to human activities (use of leaded gasoline) leadhas 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 portionswill 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 exposureinclude possible decrease in memory; weakness in the fingers, wrists, or ankles; and anemia. Children are moresensitive to the effects of lead than adults. Lead can cause premature birth, smaller babies, decreased intelligentquotient 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 couldoccur if residential wells become contaminated by migration of site contaminants. The wells were not contaminatedwith lead at the last monitoring date.
The short- and long-term health effects caused by exposure to 2-methylnaphthalene have not been studied. Thissubstance is a solid at room temperature. It is used to make other chemicals that are used as pesticides. There is noinformation about the release of this chemical into the environment or what happens to this substance after it isreleased. (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 orchronic duration exposure to 2-methylnaphthalene in humans or animals. There is also no information on thecarcinogenic potential of 2-methylnaphthalene in humans or animals. There are no regulations or advisories for thischemical at this time. This chemical is a potential contaminant of residential wells.
Naphthalene is a white solid substance with the characteristic odor of tar or mothballs. It is released into the air fromthe burning of fuels such as coal and oil, and from the use of mothballs containing naphthalene. Naphthaleneevaporates 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 HemolyticAnemia (a condition involving the breakdown of red blood cells). These effects can occur from either breathing oreating naphthalene. Cancer has not been seen in humans or animals exposed to naphthalene. (ATSDR ToxicologicalProfile for Naphthalene/2-Methylnaphthalene)
Naphthalene was found in the on-site groundwater at 110 ppb. The lifetime health advisory for this chemical is 20ppb. The estimated daily ingestion of this chemical in drinking water is considerably less than the level of the lowestobserved serious adverse health effects in humans and animals. This chemical is a potential contaminant of residentialwells surrounding the NSL site.
Trichloroethylene is a man-made chemical that does not occur naturally in the environment. It is mainly used as asolvent to remove grease from metal parts.
Trichloroethylene can easily enter the body through ingestion, inhalation, or dermal contact. This chemical is notlikely to build up in the body. Exposure to high levels of trichloroethylene can cause dizziness, sleepiness, anddamage to some of the nerves of the face. It has caused rashes in some individuals who were exposed dermally. It isnot known if this chemical causes cancer or will affect human reproduction. (ATSDR Draft Toxicological Profile forTrichloroethylene)
The intermediate MRL for trichloroethylene is 100 g/kg/day, which assumes exposure for longer than 14 days, butless than 1 year. The estimated daily ingestion dose is considerably lower than the intermediate MRL. TCE was notfound in the last sampling of the residential wells. This chemical is a potential contaminant of private residentialwells.
As discussed in the Health Outcome Data subsection, cancer mortality data on Boone County, Indiana, and the UnitedStates are available by race, gender, and year (1950-1979). The cancer rates of Boone County were compared toIndiana 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 stateand U.S. rates for all race/gender groups.
- Are both the NSL and ECC sites being addressed for cleanup together orseparately?
Cleanup for the NSL and ECC sites will be addressed separately.
- 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 ofdrinking 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 ofhypertension and would complicate clinical treatment of hypertensive patients on salt-restricted diets.
- 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 iscorrosive to all tissues and can cause serious burns. This chemical should be biodegraded, however, to someextent in the ground and should be degraded further by microorganisms upon exposure to open air. Theambient conditions in Finley Creek and the unnamed ditch would have to be just right for this chemical to bereleased in the air. To assess the long-term health effects of this leachate, an evaluation of the cancer data forBoone County was done. Results show that there has not been a significant increase of cancer in the pastforty years.
- 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 maybe/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 duringthe residential well sampling.
- 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.