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PRELIMINARY PUBLIC HEALTH ASSESSMENT

NATIONAL SOUTHWIRE ALUMINUM COMPANY
HAWESVILLE, HANCOCK COUNTY, KENTUCKY


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

Sampling data and supporting site-related information suggestthat contaminants have been released to the air, groundwater,surface and subsurface soils, surface water, and sediment on siteand off site. The narrative and tables presented in this sectionidentify several contaminants of concern that have been selectedfor further evaluation in subsequent sections of this PublicHealth Assessment to determine whether exposure to them haspublic health significance. Identifying contaminants in thissection does not imply that exposure will result in adversehealth effects.

Contaminant selection considers the following factors:

  1. Concentrations of contaminants on site and off site.
  2. Sampling plan design, field data quality, and laboratory data quality.
  3. Relationship of on-site and off-site concentrations to Public Health Assessment Comparison Values for noncarcinogenic health endpoints and for carcinogenic endpoints, and also to other selection values.
  4. Community health concerns.

ATSDR also conducted a search of the EPA Toxic Chemical ReleaseInventory (TRI) for chemical release information about NSA andother facilities in the vicinity. The TRI shows NSA reports airreleases of aluminum, chlorine, copper, and hydrogen fluoride, inaddition to releases of copper and sulfuric acid to the OhioRiver. Several major industries are reported in TRI for theKentucky side of the river. However, all those reported are atleast 4 to 5 miles from NSA and are unlikely to contribute anysubstantive concentrations of contaminants of concern to the NSAlocation. A few relatively small industries are listed in theTRI at Tell City, Indiana. These report air releases of volatileorganic chemicals, which are not chemicals of concern for the NSAfacility.

The several contaminants of concern selected to be addressedfurther in this public health assessment are listed in Table 1.


Table 1.

Contaminants of Concern in One or More Media
AluminumArsenicCobaltCyanideFluoride
LeadManganeseNickelPolychlorinated
biphenyls

Data tables include several abbreviations for identifying sourcesand for clarifying information:

Comparison Values Abbreviations
* RfDGReference Dose-based Guide
* LTHALifetime Health Advisory
* MCLMaximum Contaminant Level
* TLVGThreshold Limit Value Guide

Clarifying Abbreviations
* ppmparts per million
* ND contaminant not detected
* NAcontaminant not analyzed for
* NIno information about contaminant
* N.F.D.contaminant not further defined
* Jestimated value
* Npresumed evidence of material
* <less than
* NTPNational Toxicology Program

RfDG comparison concentrations are based on EPA's estimates ofthe daily exposure to a contaminant that is unlikely to causeadverse health effects. LTHAs represent contaminant levels indrinking water at which EPA believes adverse noncarcinogenichealth effects will not occur. MCLs represent contaminantconcentrations in drinking water that EPA deems protective ofpublic health. The TLVG represents an estimated air contaminantselection value, which for this assessment is set equal to1/420th of the industrial work-place health guideline valuedeveloped for that contaminant by the American Conference ofGovernmental Industrial Hygienists

Specific information about contamination is presented infollowing sections and in tables in Appendix B. Note thatcontaminants detected in any one medium are listed in tables forall media--including those media for which the contaminant wasnot detected, or not analyzed for, or no contaminant informationwas obtained.

A. ON-SITE CONTAMINATION

Waste Material

    Electrostatic Precipitator Particles

Wastes captured by the precipitator system have been disposed ofin on-site ponds. Laboratory analyses for several of thecontaminants of concern showed that the materials containsubstantive levels of aluminum, fluoride, and nickel. Specificcontaminant data are provided in Table 2, of Appendix B.

    Process Water Discharges

Many samples of process waste water have been analyzed incompliance with NSA's waste water permit. Some waste water isdischarged to the drainage ditch system west of the process areaand some is released directly to the river along the eastproperty line. Most of the contaminants of concern--aluminum,cyanide, fluoride, lead, manganese, nickel--have been detected inthe waste water. Specific contaminant data are provided inTable 3, of Appendix B.

    Pond Sediment

Lead and arsenic were detected in a sample of sediment from anunidentified on-site pond. Specific contaminant data areprovided in Table 4, of Appendix B. Since particles capturedfrom the air control system are also disposed of in ponds,aluminum, fluoride, and nickel--as reported in Table 2--are expected to be present at one or more of the pond locations.

    Pond Water

Analyses of a single sample of water taken from an unidentifiedon-site pond detected cyanide. Specific contaminant data areprovided in Table 5, of Appendix B.

Air Quality

NSA has been monitoring ambient air quality for fluoride on sitefor several years. NSA also reports releasing aluminum toambient air, but no aluminum data are known to be available. Since May 1991, NSA has conducted periodic fluoride monitoringwithin the potroom. Specific air contaminant data are providedin Table 6, of Appendix B.

Soils

Laboratory analyses of several samples of on-site surface soils(sample length and depth not described) and subsurface soilstaken principally by waste management units and other plantcomponents show that all of the contaminants of concern, exceptcyanide, have been detected. Specific contaminant data areprovided in Table 7, of Appendix B.

Groundwater

    Drinking Water Wells

Cyanide has been detected in many samples of groundwater from twowells that have been used as a source of potable water, sinceoperations began, for the employees at NSA and Southwire-KentuckyDivision and for persons at the adjacent airport. These wellsdraw from the thick zone of alluvium that blankets the sitevicinity. When cyanide levels increased in the well initiallyused, the second well was converted from industrial water supplyto potable water supply. Fluoride and manganese were detected inone sample. Specific contaminant data are provided in Table 8,of Appendix B.

    Process Water Supply Wells and Monitoring Wells

Many samples have been taken of groundwater from monitoring wellsand wells used solely for process water supply. These wells drawfrom the thick zone of alluvial soils that blanket the site area. Sample analyses have detected all of the contaminants of concern,except for PCBs. In general, groundwater contaminant levels seemto be greatest in the vicinity of the ponds and in the areabetween the ponds and the river. Specific contaminant data areprovided in Table 9, of Appendix B.

Surface Water--Drainage Ditch

Analyses of several water samples taken from on-site areas of thedrainage ditch detected most of the contaminants of concern;including aluminum, arsenic, cyanide, fluoride, lead, manganese,and nickel. Specific contaminant data are provided in Table 10,of Appendix B.

Sediment--Drainage Ditch

Several samples of sediment taken from the on-site area of thedrainage ditch were analyzed. Analyses showed that the sedimentscontained all of the contaminants of concern, except PCBs. Specific contaminant data are presented in Table 11, of Appendix B.

Vegetation

NSA analyzes grassy vegetation on site for fluoride. Samples aretaken from several locations during each month of the growingseason. Specific contaminant data are presented in Table 12, ofAppendix B.

B. OFF-SITE CONTAMINATION

Ambient Air

Samples of ambient air taken daily for several years from onenearby off-site monitoring station to the north of the site inKentucky and from four stations in the vicinity of Tell City andTroy Indiana have been analyzed for fluoride. The data indicatefluorides in air are well distributed throughout the area beingmonitored. NSA releases fluorides to ambient air and alsoreports releasing aluminum, but no sampling data are known to beavailable for aluminum. The Big Rivers electric station,adjacent to NSA, is likely to emit some fluorides from itscoal-fired boilers. Specific fluoride data for off-site ambientair are presented in Table 13, of Appendix B.

Soils

Laboratory analyses of two samples of off-site surface soils(sample length and depth not described) taken from 100 to 700feet west of the site show that all of the contaminants ofconcern, except cyanide, lead, and PCBs, have been detected. Natural soils usually contain inorganic constituents of the typenoted. Specific contaminant data are provided in Table 14, of Appendix B.

Groundwater

    Monitoring Wells

A groundwater sample was taken from each of two off-sitemonitoring wells 100 to 700 feet west of the site perimeter, inan apparently upgradient direction with respect to groundwaterflow. The wells draw from the thick alluvium that blankets thesite vicinity. The analyses showed that all of the contaminantsof concern were present in the groundwater at those locations,except for cyanide, fluoride, and PCBs. Natural groundwaterusually contains constituents of the type noted. Specificcontaminant data are shown in Table 15, of Appendix B.

    Public Water Supply Wells

Water quality data were obtained from a few samples of untreatedand treated groundwater from the public water systems that supplythe nearby communities of Hawesville Kentucky and Tell City,Cannelton, and Troy Indiana. These well systems are located onthe banks of the Ohio River and draw from the thick zone ofalluvial soils that blanket the river area. Therefore, thegroundwater drawn is likely to consist of some river water thatenters the alluvial zone and some aquifer groundwater that flowsto the wells from higher elevations. Data are also available forLewisport and East Daviess public water systems. The plausiblenatural or man-related sources of contaminants detected in publicsupply wells have not been compiled. The analyses results showthat one or more of the samples contained several contaminants ofconcern; including arsenic, fluoride, lead, and manganese. Specific contaminant data are shown in Tables 16, 17, 18, 19, and20, respectively, of Appendix B.

    Private Wells

Several private wells have been sampled at residences andbusinesses, predominantly close to the south and southwest edgesof the site. The wells probably draw from the alluvial soils,but information is not available to confirm this. The plausiblenatural or man-related sources of contaminants detected inprivate wells have not been compiled. Analyses of groundwatersamples showed that three contaminants of concern were detected--arsenic, fluoride, and lead. Specific contaminant data are shownin Table 21, of Appendix B.

Surface Water

    Ohio River

Two samples of river water taken at nearby upstream anddownstream locations have been analyzed. The plausible naturalor man-related sources of contaminants detected in river waterhave not been compiled. Results show that all the contaminantsof concern were detected, except for cobalt and PCBs--andpossibly cyanide. It is unclear whether cyanide was actuallypresent at a low level because of the manner in which the cyanideresult was reported (<0.030 ppm). Specific contaminant data areshown in Table 22, of Appendix B.

    Public Water Supply--Evansville, Indiana

Evansville, Indiana, about 60 miles downstream from the site usesthe river as the source of its municipal water supply. A limitedamount of analytical data have been obtained for raw river waterand also for treated water at the treatment plant. The plausiblenatural or man-related sources of contaminants detected in riverwater and finished water have not been compiled. The data showthat aluminum, arsenic, fluoride, and manganese were atdetectable levels. It is noteworthy that all the contaminantsdetected occur at low levels. Specific contaminant data areshown in Table 23, of Appendix B.

    Drainage Ditch

In one sample of ditch water taken at the upgradient edge of thesite, by the property line, three contaminants of concern weredetected. Those were cyanide, fluoride, and manganese. Specificcontaminant data are shown in Table 24, of Appendix B.

Sediment--Drainage Ditch

One sample of sediment was taken from the ditch at the upgradientedge of the site, by the property line; all contaminants ofconcern were detected, except for PCBs. Specific contaminantdata are shown in Table 25, of Appendix B.

Vegetation

During each month of the growing season, NSA analyzes fluoridecontent of grassy-type vegetation samples taken along roadsidesacross a network of about 50 stations off site--at distancesranging up to 8 miles from the property. The plausible naturaland man-related sources of the fluoride have not been compiled. Specific contaminant data are shown in Table 26, of Appendix B.

Fish in River

KDEP and other agencies have sampled various species of fish atmany locations in the Ohio River and have found some species tocontain elevated levels of PCBs, a contaminant of concern, andalso chlordane. The plausible sources of these contaminants havenot been compiled. Sample data for fish taken from the vicinityof the Cannelton Lock and Dam, about 5 miles upstream of thesite, are summarized in Table 27, of Appendix B.

C. QUALITY ASSURANCE AND QUALITY CONTROL

Reference documents contain limited quality assurance informationfor investigations, sampling, and laboratory analyses. Inpreparing this assessment, ATSDR has presumed that protocols andresults are valid and has used the information in itsevaluations. The completeness and reliability of the informationcould affect the validity of ATSDR's conclusions.

D. PHYSICAL AND OTHER HAZARDS

ATSDR's observations of the site suggest that there are nophysical or other hazards beyond those normally associated withthe aluminum reduction process and its associated activities.


PATHWAYS ANALYSES

ATSDR identifies human exposure pathways by examiningenvironmental and human components that might lead to contactwith contaminants. A pathway analysis considers five elements: asource of contamination, transport through an environmentalmedium, a point of exposure, a route of human exposure, and anexposed population. Completed exposure pathways are those forwhich the five elements are evident and indicate that exposure toa contaminant has occurred in the past, is currently occurring,or will occur in the future. Potential exposure pathways arethose for which one or more of the elements is not clearlydefined but could be present. Potential pathways indicate thatexposure to a contaminant could have occurred in the past, couldbe occurring now, or could occur in the future.

Pathway analyses for the site area indicate that there areseveral completed pathways associated with surface water, air,groundwater, and soils. The completed pathway elements aresummarized on Table 28, in this section.

Several potential exposure pathways--associated with surfacewater, sediment, wastes at the dump pad, garden produce, air, andfish--could also exist. The potential pathway elements aresummarized on Table 29, in this section.

Table 30 estimates the number of exposed persons associated withcompleted exposure pathways and the number of potentially exposedpersons for potential exposure pathways

A. COMPLETED EXPOSURE PATHWAYS

Air Pathways

Data from NSA's several air ambient monitoring stations show thatfluoride is present in ambient air on and near the site and inthe Troy/Tell City vicinity. NSA reports aluminum is alsoreleased to ambient air, however none of the contaminants ofconcern--except fluoride--are being analyzed for in that program. The coal-fired Big Rivers electric station, adjacent to NSA, isalso likely to be a source of airborne fluoride. KDEP personnelreport that the electric company's stack sampling program doesnot include analyzing for any of the contaminants of concern, sothe suspected fluoride releases from coal burning and, possibly,coal storage cannot be confirmed. Some of the other industriesin the area also release contaminants to ambient air, but dataare not available to confirm whether any of the contaminants ofconcern are included. Work-place sampling also has shownfluoride is present in the potroom.

Releases of fluoride and aluminum to ambient air at NSA fromstacks or through fugitive emissions from their process orhandling areas result in past, current, and future inhalationexposure by workers on site and by workers and residents in thesurrounding area, including nearby towns. Fluoride releases inthe potroom pose similar exposures to workers at that location.

Wind will tend to re-suspend airborne contaminants that had beendeposited on the ground surface--resulting in transport andinhalation exposure to workers on site, workers off site, and toarea residents. The extent of inhalation exposure andcontaminant uptake through wind resuspension cannot be evaluatedseparately from exposure through inhalation of ambient air.



Table 28.

COMPLETED EXPOSURE PATHWAYS (Page 1 of 2)
PATHWAY NAMEEXPOSURE PATHWAY ELEMENTS TIME
SOURCE MEDIUM POINT OF
EXPOSURE
ROUTE OF
EXPOSURE
EXPOSED
POPULATION
Ambient air,Work placeairNSA
Big Rivers
Electric
AirOn site andVicinityInhalation Workers andResidentsPast
Present
Future
NSA private
well
NSA (ditch and pond water)
Natural
River
GroundwaterTwo plantsand Airport Ingestion
Inhalation
Workers andAirportusersPast
Present
Future
Privatewells
(off site)
Uncertain
(possiblynatural,
river, NSA)
GroundwaterOff-siteprivate wellsIngestion
Inhalation
Workers andResidentsPast
Present
Future
Public watersupply(local area)Uncertain
(possiblynatural orriver)
GroundwaterArearesidences &businesses Ingestion
Inhalation
System users Past
Present
Future
Public watersupply
(Evansville)
Uncertain(dischargesto river)Surface water
(Ohio River)
Evansville
residences &
businesses
Ingestion
Inhalation
System usersPast
Present
Future





Table 28.

COMPLETED EXPOSURE PATHWAYS(Page 2 of 2)
PATHWAY NAMEEXPOSURE PATHWAY ELEMENTS TIME
SOURCE MEDIUM POINT OF
EXPOSURE
ROUTE OF
EXPOSURE
EXPOSED
POPULATION
Ohio Riverwater (localarea)Many unknown
dischargers
and NSA
Surface waterOhio RiverIngestionSwimmers
Skiers
Past
Present
Future
Soil
(local area)
NSA
Natural
SoilOn site
Off site
properties
Ingestion
Inhalation
Workers
Farmers
Residents
Past
Present
Future




Table 29.

OTENTIAL EXPOSURE PATHWAYS
PATHWAY NAMEEXPOSURE PATHWAY ELEMENTS TIME
SOURCE MEDIUM POINT OF
EXPOSURE
ROUTE OF
EXPOSURE
EXPOSED
POPULATION
Waste water
(plant
wastes)
NSASurface water
(wastes)
NSA processarea, ditchsystemIngestionNSAworkers,contractorsPast
Present
Future
Pond andditchsediment
(plant
wastes)
NSASediment
(wastes)
Pond and ditchsystemIngestionRemedialworkersPast
Future
Pond andditch water
(plant
wastes)
NSASurface water
(wastes)
Pond and ditchsystemIngestionRemedialworkers Past
Future
Dump pad
(plant
wastes)
NSAAirDump padInhalation
Ingestion
NSA workersPast
Present
Future
VegetationNSA, naturalGardenproduceLocalresidencesIngestionLocalresidentsPast
Present
Future
FishUnknowndischargers,
possibly NSA
FishResidencesIngestionFishermen
andfamilies
Past
Present
Future



Page 1 of 3

Table 30.

ESTIMATED POPULATION FOR COMPLETED AND POTENTIAL EXPOSURE PATHWAYS
Estimated Exposed Populations and
(Potentially Exposed Populations)
Affected by a Completed Exposure Pathway or (Potential Exposure Pathway)* :
Exposure to Contaminants**
LocationNumber Al As Co Cn Fl Pb Mn NiPCB
Workers; NSA800ai----pwpw
ai
--pw----
Workers; NSAUnknown--------ws--------
Workers; Southwire
Kentucky Division
and airport
100ai----pwpw

ai

--pw----
Workers; other nearbyindustries200aipws----pwsaipwspws----
Other workers; anothernearby industry10aipw----pw
ai
pw------
Some nearby residents,
in Kentucky
12aipw----pw
ai
pw------
Other nearby residents,in Kentucky6 aipws----pwsaipwspws----
NSA and nearby workers,nearby residentsUnknownsososo--sososososo
* Refer to Tables 27 and 28 for summary of completed and potential exposure pathways.
** Refer to Page 3 of 3 for explanation of alpha code information.





Table 30.

TABLE 30 ESTIMATED POPULATION FOR COMPLETED AND POTENTIAL EXPOSURE PATHWAYS (Continued) Page 2 of 3
Estimated Exposed Populations and (Potentially Exposed Populations)Affected by a Completed Exposure Pathway or (Potential Exposure Pathway)* :
Exposure to Contaminants**
LocationNumber Al As Co Cn Fl Pb Mn NiPCB
Other residents in
Kentucky and Indiana
15,000ai------pws
ai
--pws----
Other residents in
Kentucky and Indiana
14,000--pws--------------
Other residents in
Kentucky and Indiana
3,000----------pws------
Additional residents inKentucky and IndianaUnknownai------ai
pw
--------
Nearby swimmers, skiersUnknownswsw--sw?swswswsw--
Users, Evansville watersupply140,000pwspws----pws--pws----
(NSA workers, remedialworkers); NSA waste water,ditch, ponds, dump pad(Un-
known)
wswswswswswswsws--
(Area residents withgardens)(Un- known)--------gp--------
(Area fishermen &
families)
(Un-
known)
----------------fi
* Refer to Tables 27 and 28 for summary of completed and potential exposure pathways.
** Refer to Page 3 of 3 for explanation of alpha code information.



Table 30.

ESTIMATED POPULATION FOR COMPLETED AND POTENTIAL EXPOSURE PATHWAYS (Continued) Page 3 of 3
Contaminant Codes Pathway Codes
Al Aluminum pw Private well
As Arsenic pws Public water supply
Co Cobalt so Soil
Cn Cyanide ai Ambient air
Fl Fluoride sw Surface water
Pb Lead ws Wastes
Mn Manganese p Garden produce
Ni Nickel fi fish
PCB Polychlorinated
biphenyls
   

NSA Private Well Pathways

Analyses have shown that three contaminants of concern--cyanide,fluoride, and manganese--are present in NSA's potable water,which it has obtained over the years from two of its threegroundwater supply wells. The wells are reported by NSA toextend about 130 feet into the zone of alluvial soils thatunderlies the site and surrounding area. After cyanideconcentrations rose in Well #1 in 1985, NSA's representativereports they began using Well #3 for potable water. Cyanide andfluoride concentrations reported in groundwater across the siteare at relatively higher levels at the disposal ponds, in thehydraulically downgradient area between the ponds and the river,and at the dump pad building; suggesting that the ponds and dumppad have been primary sources of releases. Pumping at NSA'spotable water well and its industrial supply wells depress thegroundwater level locally. This depression creates a flowgradient pattern that under certain conditions (possiblyseasonal) might draw more contaminated groundwater (such asexists beneath the waste disposal areas) toward the industrialand potable well locations. Intermittent movement ofcontaminated river water toward NSA's water supply wells alsoseems plausible. Analytical data for the municipal well systemsshow that fluoride and manganese are naturally occurring elementsin area groundwater and show that cyanide is not. ATSDRconcludes that NSA's spent potliners are probably the singlesource of the cyanide, and also a portion of the fluoride, foundin groundwater beneath its property. Information is notsufficient to decide whether NSA contributes manganese to itsunderlying groundwater.

NSA uses its private well system for potable water (and processwater) and also provides potable water to the adjacentSouthwire-Kentucky Division and county airport. Therefore,persons using water at these locations for potable purposes havebeen exposed in the past to low levels of cyanide, fluoride, andmanganese principally through ingestion and inhalation(aerosols/showering), are being exposed now, and will be exposedin the future.

Off-site Private Wells Pathways

Several of the private wells serving nearby Hancock Countyresidents and workers have been sampled. A few contaminants ofconcern--fluoride, arsenic, and lead--have been detected, but atlow concentrations that are within the range that have beenobserved to occur naturally in some groundwater aquiferselsewhere in the country. ATSDR's review of local well locationsin relation to hydrogeologic conditions suggests that theseprivate wells are not likely to be affected by groundwatercontamination that originates at NSA. However, information isnot sufficient to confirm this. All private off-site wells arein what would normally be hydraulically upgradient orcrossgradient directions. Normal groundwater flow direction isapproximately eastward, toward the river--except during floodstage, when some temporary flow direction reversal is likelyalong the bank area. No private wells exist between the site andthe river. Also, there are no private wells westward of the pondand process areas for a distance of about ¾ miles. One of theprivate wells is very close to the river and therefore mightreceive some inflow of contaminated river water.

River water that enters the lowlands beyond NSA's property atflood stage contains dissolved contaminants and contaminatedparticles. Some of these contaminants may subsequently enter thegroundwater system and affect water quality at some privatewells. The flood-water's contribution to the chemical burden inprivate well water cannot be realistically estimated.

Persons using groundwater from the private wells that were testedhave been exposed in the past to low levels of fluoride, lead,and arsenic principally through ingestion and inhalation(aerosols/showering), are being exposed now, and will be exposedin the future.

Public Water Supply Pathways--Local Area

Sampling of raw or finished water for the local public watersystems at Hawesville, Kentucky, and at Cannelton, Tell City, andTroy, Indiana, shows that several contaminants of concern havebeen detected; including arsenic, fluoride, lead, and manganese. Fluoride has been shown to be present in the public systems atLewisport, and East Daviess, Kentucky, whose wells are fartheraway. The contaminant concentrations detected are in the rangeof the natural levels that have been recorded in groundwatersystems elsewhere.

ATSDR believes it is extremely unlikely that the groundwaterserving these public water supply systems is affected bycontaminants that originate at NSA. Wells for the nearestsystems--Tell City (½ mile), Hawesville (3 miles), Cannelton(3 miles), and Troy (3 miles)--are constructed in alluvial soilsalong the river bank and are likely to be fed by river water thatenters the alluvial zone and by aquifer groundwater that flows tothe wells from higher elevations. Although the alluvial soilzone extends beneath the ½-mile expanse of river and across bothriver banks, even the nearest wells at Tell City--which areimmediately across from the site--do not appear likely to drawany contaminated groundwater that originates beneath the sitearea. Site groundwater is believed to discharge into the river. The Tell City wells are expected to obtain their water both fromthe intervening river--which would dilute contaminants receivedby groundwater discharge from NSA--and from the Indiana area ofthe alluvial aquifer.

Persons using groundwater from the public systems have beenexposed in the past to low levels of arsenic, fluoride, lead,manganese, and nickel principally through ingestion andinhalation (aerosols/showering), are being exposed now, and willbe exposed in the future.

Ohio River/Public Water Supply Pathways--Evansville Indiana.

Evansville, Indiana, approximately 60 river-miles downstream fromthe site draws its municipal water supply from the river. Potential sources of contaminants in river water are varied andinclude at least industrial discharges, municipal discharges,vessel discharges, groundwater inflow, and surface water runoffin the total watershed upstream of the city. Thus, the specificchemicals and their concentrations are likely to vary with time,and any chemicals detected cannot be directly associated with anyspecific source. Levels of contaminants of concern detected inboth raw and finished water (aluminum, arsenic, fluoride, andmanganese) are low.

Persons using river water received through the public system havebeen exposed in the past to low levels of aluminum, arsenic,fluoride, and manganese principally through ingestion andinhalation (aerosols/showering), are being exposed now, and arelikely to be exposed in the future.

Other Ohio River Water Pathways

Sources of contaminants in the river water are varied and cannotbe directly associated with any specific source. The specificchemicals and their concentrations are likely to vary, to someextent, with time.

Low, to relatively low, levels of several of the contaminants ofconcern are present in the Ohio River waters; including aluminum,arsenic, fluoride, lead, manganese, and nickel. The analyticalresults for cyanide in 1986 are not reported in sufficientlyprecise terms to decide whether that compound was actuallydetected. Samples taken in 1989 did not detect any cyanide.

The river is used for recreation. Therefore, swimmers and waterskiers, and to some extent fishermen, have been exposed in thepast to low levels of contaminants in river water (includingaluminum, arsenic, fluoride, lead, manganese, and nickel)principally through ingestion, are being exposed, and are likelyto be exposed in the future.

The nearest downstream user of river water for drinking water isEvansville, Indiana; this exposure pathway was described earlier.

River water probably is used for crop irrigation and for farmanimals, which, in turn, can lead to human exposure to chemicalsthrough consumption of farm products. For the levels of thechemicals of concern that have been detected, this use of riverwater is not likely to be a substantive pathway. Hence, it isnot discussed further in this assessment.

Soil Pathways

Essentially the same contaminants of concern were detected insurface soils on and off site. Potential sources of thecontaminants of concern off site include, at least, the naturallyoccurring chemical constituents in soil, constituents in flooddeposits in low-lying areas, chemicals in farm pesticide andfertilizer applications, and also constituents of airbornedeposition from NSA or other sources. Arsenic, cobalt,manganese, and nickel were present in both on- and off-sitesurface soils at low levels and within a range of values at whichthey have been found to occur naturally in soils elsewhere. Leadwas present at similarly low levels in on-site surface soils andwas not detected in off-site samples. Both aluminum and fluoridewere present at substantially greater concentrations in surfacesoils on site, which suggests a contribution to on-site surfacesoils through NSA activities. However, even these higher on-sitevalues for aluminum and fluoride are within the range at whichthey have been found to occur naturally elsewhere in the country. PCBs were detected only on site, which suggests that NSA is thesource. PCBs were found at low levels in surface soils--exceptin the field where NSA temporarily stored some excavated soils.

In subsurface soils, contaminants were not at extraordinaryconcentrations, except for some high levels of PCBs found in adeep foundation excavation and at the dump pad location.

Exposure to soil contaminants has occurred in the past, isoccurring, and will occur in the future. On site, propertymaintenance or construction workers are the principal populationsthat are likely to be exposed, primarily through ingestion andinhalation of contaminated particles. Exposures to contaminantsin surface soils are likely to occur with relative frequency forsome workers and may, therefore, be of greater importance thaninfrequent exposure to contaminants in the subsurface zone. Offsite, the principal exposed populations include workers at otherfacilities, farmers working fields and mowing equipmentoperators--primarily through inhalation of contaminatedparticles, and, to some extent, area residents--through ingestionand inhalation of contaminated particles.

B. POTENTIAL EXPOSURE PATHWAYS

Waste Water Pathways (plant wastes)

Process waste water being discharged to the ditch system on siteand to the river has been shown to contain low levels of some ofthe contaminants of concern. Those include aluminum, cyanide,fluoride, lead, manganese, and nickel. Comparing the samplingdata available for the waste water discharge with data forgroundwater from the industrial wells that supply the productionprocesses suggests that the plant processes add littlecontaminant load to the water being discharged.

Workers and contractors may sometimes encounter waste water inthe process area or at its discharge points to the river andditch system. Therefore, those people are potentially exposed inthe past, present, and future to the aluminum, cyanide, fluoride,lead, manganese, and nickel contained in the waste waters. Exposure would be primarily through incidental ingestion.

Pond and Ditch Sediment Pathways (plant wastes)

Waste disposal and waste water and surface runoff discharges havedeposited contaminants as sediment in the ponds and in the ditchsystems. A limited set of data for pond sediment shows thatarsenic and lead are present at low levels. Reference documentsdo not indicate whether other contaminants of concern are presentin pond sediments. However, analyses of particles captured bythe air control system--which, together with scrubber residue,are the predominant wastes currently being disposed of on site--indicate that relatively high levels of aluminum and fluoride arelikely to be present in some ponds. Analyses of sediment samplestaken from the drainage ditch show that all of the contaminantsof concern were detected, except for PCBs. The concentrations ofaluminum, arsenic, fluoride, manganese, and nickel detected inthe on-site samples are substantively higher than were detectedin a single sample obtained upgradient in the area of the ditchthat is just beyond the property line. NSA reports thatsediments were removed from the ditch system in 1990 and 1991. Thus, fewer contaminants, or lower concentrations, might bepresent in the ditch bottom at this time; sampling data are notavailable to confirm current conditions.

Past and future remedial workers are the principal populationpotentially exposed to pond and ditch sediments, ingestion beingthe primary exposure route.

Pond and Ditch Water Pathways (plant wastes)

Waste disposal and waste water and surface runoff have dischargedcontaminated water to ponds and to the ditch system. A limiteddata set for water taken from North Pond before its closure in1986 shows that cyanide was present at elevated levels. No otherinformation about contaminants is available for water in any ofthe ponds. Low levels of all of the contaminants of concern werereported for ditch water on site, except for PCBs which were notdetected. Fluoride was especially elevated. For one off-sitesample taken upgradient at the south property line, onlyfluoride, manganese, and cyanide were detected at low levels. The presence of cyanide at that location may result from pondingof plant effluent or site runoff because the ditch bottom hasessentially no gradient.

Past and future remedial workers are the principal populationpotentially exposed to pond and ditch water; the primary exposureroute being ingestion.

Dump Pad Building Pathways

The potliners brought into the dump pad building for demolitionand subsequent off-site disposal reportedly contain elevatedlevels of cyanide and possibly other metals. No information isavailable in reference documents to evaluate constituents andconcentrations. During potliner demolition and building cleanup,contaminated particles are expected to be released into theair--whereupon some particles will redeposit within the buildingand some will be removed by the air system and disposed of in awaste pond. Before enclosing the pad, airborne contaminantswould have deposited on the ground beyond the pad area.

Past, present, and future workers who demolish the potliners,load the materials for disposal, and clean up the dump pad arethe principal populations potentially exposed to contaminants. Potential exposure routes are inhalation and incidentalingestion.

Vegetation Pathway

NSA samples and analyzes grassy-type vegetation for fluoride atmore than 50 stations on and off site in response to regulationsthat address potential adverse fluoride effects on ruminant (cud-chewing) animals. Off-site samples are taken at the edges ofroadways. Specific fluoride levels in vegetation are influencedby several factors that might include the absorptive capabilityof various vegetation species, the concentration of naturallyoccurring fluoride in soil, soil chemistry, and external fluoridesources. ATSDR examined the laboratory data for an indicationwhether an external source, such as stack or fugitive airemissions, is a probable contributor to vegetation fluoridelevels. During this examination, it was noted that higherdetected fluoride levels--above 10 ppm--were observed invegetation at the greatest rate on site and within 1 mile. Theobservation suggests, but does not confirm, that NSA's airemissions could contribute to elevated fluoride levels in thegrasses.

The presence of apparently elevated fluoride levels in somegrassy vegetation suggests there is a potential for humanexposure--past, present, future--to elevated fluoride inconsumable vegetation, for example, garden produce, soy beans,corn. Garden produce raised and consumed by local residents isof greatest concern because of ingestion frequency. However,information is not available to determine whether local gardenproduce contains fluorides.

Fish Pathway

Advisories have been in effect for several years for selectedgame fish species for the Ohio River within Kentucky/Indiana (andalso for other reaches) for PCBs, a contaminant of concern, andfor chlordane. The nearest sampling station is the CanneltonLock and Dam, about 5 miles upstream from the site. The closestdownstream sampling station is about 120 miles away. Manyplausible sources of these contaminants exist within the river'sextensive watershed. There does not appear to be a definablelink between the PCBs in soils at NSA and fish contamination, andchlordane has not been shown to be a contaminant at NSA.

Fishermen--past, present, and future--and their familiespotentially are exposed to contaminants of concern throughingestion of fish taken from the river. However, if fishermenheed the fish advisories, exposure should not occur.


PUBLIC HEALTH IMPLICATIONS

A. TOXICOLOGICAL EVALUATION

Introduction

This section discusses health issues for persons exposed tospecific contaminants (for completed pathways), discusses healthoutcome data, and addresses specific community health concerns. To evaluate noncancer health effects, ATSDR has developed aMinimal Risk Level (MRL) for certain contaminants commonly foundat hazardous waste sites. The MRL is an estimate of daily humanexposure to a contaminant below which non-cancer adverse healtheffects are unlikely to occur. MRLs are developed for routes ofexposure and for the length of exposure - acute (less than 14days), intermediate (15 to 364 days), and chronic (equal to orgreater than 365 days). ATSDR presents these MRLs inToxicological Profiles. These chemical-specific profiles provideinformation on health effects, environmental transport, humanexposure, and regulatory status. If an ATSDR MRL is notavailable, then EPA's Reference Dose (RfD) is used. The RfD isan estimate of daily human exposure to a contaminant for alifetime below which (noncancer) health effects are unlikely tooccur. Therefore, the mere presence of a chemical does not implythat harm will result from exposure. A contaminant at aconcentration lower than that chemical's MRL or RfD should poseno appreciable public health hazard with respect to noncancerousadverse health effects.

Cancer is a group of diseases characterized by uncontained growthand spread of abnormal cells. Cancer cells multiplyuncontrollably, destroying normal cells, and can spread fromtheir site of origin to other parts of the body. A chemicalcapable of causing damage leading to cancer is called acarcinogen. The latency period, or amount of time betweenexposure and development of disease, ranges from a few years todecades. ATSDR estimates cancer risks by using the EPA's cancerpotency factor. That method assumes that animal data gatheredunder high dose exposure conditions can be used to estimate therisk of low dose exposures in humans. The method also assumesthat there is no safe level of exposure. There is littleexperimental evidence to confirm or refute those two assumptions. Lastly, the method assumes the 95% upper bound for the risk,rather than the average risk. In other words, there is a 95%chance that the risk of cancer is actually lower, perhaps byseveral orders of magnitude.

Since ATSDR has no methodology to determine the amount ofabsorption of chemicals through the skin, ATSDR does not haveMRLs for skin exposure. For this reason, it is difficult todetermine the health effects from skin exposure.

Health Issues by Contaminant

Aluminum

Aluminum exposure has occurred and is occurring in maintenanceand any construction or remedial workers on site and in nearbyindustries, and in swimmers and residents who live in theimmediate vicinity of the site and much farther away inEvansville, Indiana (Table 31). To estimate exposure fromdrinking water, ATSDR used the intake rate of 2 L/day for adults




Table 31.

Comparison of Estimated Exposed Dose to Health Guidelines for Aluminum
ContaminantExposure
Pathway
Health Guideline for Ingestion
(mg/kg/day)
ValueSourceExceeded byEstimated
Exposure Dose
AluminumOn-siteSurfaceSoil1RfDNo
AluminumOff-siteSoil1RfDNo
Yes (Pica Child)
AluminumPublic
WaterSupply,
E*
1RfDNo
AluminumSurfaceWater(OhioRiver)
E,H*
1RfDNo
* E = The City of Evansville, Indiana; H = Hawesville, Kentucky.

and 1 L/day for children. For soils, ATSDR used the intake rateof 100 mg/day for adults, 200 mg/day for children, and 5,000mg/day for pica children (compulsive ingestion). While ATSDRdoes not have MRLs for aluminum, the ingestion exposures inworkers from soil on site and in residents at Hawesville andEvansville from drinking water do not exceed EPA's provisionaloral Reference Dose (RfD) for aluminum (Table 31). However, theingestion exposure from surface soil in pica children living inthe immediate site area far exceeds the RfD (Table 31).

The highest concentration of aluminum (130,000 ppm = 13%) foundin surface soil on site is not substantially greater than the 8%(80,000 ppm) aluminum naturally found in soil (21). Some authorshave suggested that aluminum competes with fluoride forabsorption in the intestines (22, 23), so it is possible thatadults and children who are exposed to aluminum (Table 31) andwho also have higher than normal levels of fluoride in thedrinking water (Table 34) would absorb less aluminum.

Some people experience skin rashes from small amounts of aluminumin antiperspirants. Also, some children are sensitive to smallamounts of aluminum on their skin when injected with childhoodvaccines that contain aluminum (22, 23). Although there islittle information on long term exposure to small amounts ofaluminum in humans, non-carcinogenic health effects are notlikely to occur for workers and residents who are exposed toaluminum in soil, and drinking water, respectively (Table 31). However, levels of aluminum in off-site soil within the immediatesite area could cause some problems for pica children; although,it is not known which health effects are likely to occur for thevery small number of children (age 1 - 3 years) who usuallypractice pica. This is plausible because of the mediumconfidence in the provisional RfD. In addition, very littlealuminum (0.1 - 0.5%) is absorbed following oral ingestion (22), and the form of aluminum is not known.

Arsenic

Arsenic exposure through soil and water ingestion and skincontact has occurred and is occurring in maintenance and anyconstruction workers or remedial workers on site and in residentsand swimmers off site (Table 32).

While ATSDR does not have a chronic MRL for arsenic, EPA has anoral RfD. Because the arsenic exposure in these workers on sitedoes not appear to exceed EPA's RfD, workers are unlikely toexperience any non-carcinogenic health effects due to arsenicexposure on site. Adults who live near the NSA site and inHawesville are unlikely to experience health effects from arsenicexposure from soil or drinking water. Even though arsenicingestion from water by Hawesville children slightly exceeds theRfD, because of the uncertainty factor built into the RfD, it isstill unlikely that children will experience any adverse healtheffects. Arsenic exposure in pica children who live in theimmediate vicinity of the site exceeds EPA's oral RfD foringestion (Table 32). However, that level is approximately 100times lower than the levels that have been found to causeneurological effects in pigs (24). Also, the estimated dose insoil-pica children is based on the highest arsenic level and maynot be representative of typical daily doses. In addition,probably only very small number of children (aged 1-3 years) eatlarge quantities of soil. It is therefore highly unlikely thatsoil-pica children will experience any non-carcinogenic adversehealth effects.

Although the International Agency for Research on Cancer (IARC)and the EPA have determined that arsenic is a human carcinogen,the excess cancer risk is insignificant.



Table 32.

Comparison of Estimated Exposed Dose to Health Guidelines for Arsenic
ContaminantExposurePathwayHealth Guideline for Ingestion
(mg/kg/day)
ValueSourceExceeded by
Estimated
Exposure Dose
Arsenic On-site
surface
Soil
0.0003RfDNo
ArsenicOff-site
Surface
Soil
0.0003RfD Yes (Pica Child)
ArsenicOff-site
PrivateWell
0.0003RfDNo
ArsenicPublic
WaterSupply,
H*
0.0003RfDYes (Children)
Arsenic Public
Water
Supply,TC*,C*,E*
0.0003RfDNo
Arsenic SurfaceWater(OhioRiver)0.0003RfDNo
* H = Hawesville, Kentucky; TC = Tell City, Indiana; C =Cannelton, Indiana; E = Evansville, Indiana.

Cobalt

Maintenance and any construction or remedial workers on site, andresidents within the immediate vicinity of NSA have been and arebeing exposed to cobalt through soil ingestion and skin contact. Although cobalt salts are well absorbed, about 80% of ingestedcobalt is excreted in the urine while most of the remainingcobalt is excreted through feces (23, 25). Even in the absenceof any health guidelines, health effects are unlikely to occurfor workers and residents because the estimated ingestion dose issome 1,000,000 times lower than doses that caused skin problemsin animals. In addition, the concentrations of cobalt in soilson and near the site are similar to that found to naturally occurin soils (25).

Cyanide

Cyanide exposure through skin contact with and ingestion of waterhas occurred and is occurring in workers on site and through skincontact in swimmers off site (Table 33). While ATSDR does nothave MRLs for cyanide, the ingestion exposure for NSA workers onsite does not exceed EPA's oral RfD for cyanide. Adverse healtheffects are unlikely to occur for workers and residents who drankwater containing low levels of cyanide.

In addition, amenable cyanide is a cyanide-containing salt ormetal complex, which releases its cyanide component whenchlorinated under controlled procedures. Therefore, measurementof amenable cyanide is not useful in estimating the dose ofcyanide. Total cyanide represents a measure of all forms ofcyanide, including complexes in which the cyanide is tightlybound such as in iron cyanide.




Table 33.

Comparison of Estimated Exposed Dose to Health Guidelines for Cyanide
ContaminantExposure
Pathway
Health Guideline for Ingestion
(mg/kg/day)
ValueSourceExceeded by
Estimated
Exposure Dose
Cyanide,
Total
On-site
Private
Well
0.02RfDNo
Cyanide,Amenable On-sitePrivateWell0.02RfDNo
Cyanide,N.O.S*On-sitePrivateWell0.02RfDNo
Cyanide,N.O.S*SurfaceWater(OhioRiver)0.02RfDNo
* N.O.S = Not otherwise specified

Most forms of cyanide when present in water will form hydrogencyanide and evaporate from the water, while others aretransformed into less harmful chemicals by microorganisms in thewater or by forming a complex with metals such as iron. Theunspecified form of cyanide is absorbed if ingested in drinkingwater; however, the estimated dose is still lower than the RfD(Table 33). Therefore, adverse health effects are unlikely to occur.

Fluoride

The levels of fluoride naturally occurring in soils range from200 to 300 ppm, although mineral-rich soils may contain higheramounts. Surface water such as rivers, streams, and lakesusually contain between 0.01 and 0.3 ppm of fluoride. Fluoridelevels in groundwater are usually higher than those in rivers,streams, and lakes and range from 0.02 to 1.5 ppm. The levels insea water are however generally higher, ranging from 1.4 to 1.5ppm. The average intake of fluoride is 0.2 - 0.3 mg/day in thiscountry (27).

On-site workers were exposed and are being exposed to fluoridethrough several pathways (Tables 6 and 34). Exposure hasoccurred to all workers who drink water from the facility'swells. Some fluoride exposure also occurs to workers and arearesidents through inhalation; although, this exposure is smallcompared to the other pathways because of the small amounts offluoride in ambient air (0.000012 - 0.0053 ppm and 0.00014-0.00082 ppm as daily and monthly ranges, respectively). TheAmerican Conference of Governmental Industrial Hygienists (ACGIH)has set 2.5 mg/m3 (1.25 ppm) as a threshold limit value (TLV). This is similar to the time-weighted average (TWA) recommended bythe National Institute for Occupational Safety and Health(NIOSH), and to the permissible exposure limit (PEL) regulated bythe Occupational Safety and Health Administration (OSHA).

Most of the fluoride exposure to workers has occurred fromaccidental ingestion of fluoride-contaminated surface soil. Thisexposure would be greatest for maintenance and any remedial orconstruction workers whose activities put them in close contactwith contaminated soil. Exposure from ingesting just thefluoride contaminated drinking water is unlikely to cause adversehealth effects because the amount of exposure from drinking 2liters of water per day (the typical amount of fluid ingestedeach day by most American adults) is well below EPA's RfD of 0.12mg/kg/day. EPA developed this RfD to protect against the mostsensitive effect of fluoride exposure in adults. For most




Table 34.

Comparison of Estimated Exposed Dose to Health Guidelines for Fluoride.
ContaminantExposure
Pathway
Health Guideline for Ingestion (mg/kg/day)
ValueSourceExceeded by EstimatedExposure Dose
FluorideOn-siteSurface
Soil
0.12RfDYes (Adult)
FluorideOff-siteSurface
Soil
0.06
0.12
RfD
RfD
No (Child < 8 yr)
No (Adult & Child > 8yr)
FluorideOn-sitePrivateWell0.12RfDNo
FluoridePublicwater
Supply,
H*
0.06
0.12
RfD
RfD
Yes (Child < 8yr)
No
FluoridePublicWaterSupply,TC*0.06
0.12
RfD
RfD
Yes (Child < 8yr)
No
FluoridePublicWaterSupply, C*0.06
0.12
RfD
RfD
Yes (Child < 8yr)
No
FluoridePublicWaterSupply, T*0.06
0.12
RfD
RfD
No
No
FluoridePublicWaterSupply, L, D*0.06
0.12
RfD
RfD
Yes (child < 8yr)
No
Fluoride PublicWaterSupply, E*0.06
0.12
RfD
RfD
Yes (Child < 8yr)
No
FluorideSurfaceWater(OhioRiver)0.06
0.12
RfD
RfD
Yes (Child < 8yr)
No
* H = Hawesville, Kentucky; TC = Tell City, Indiana; C = Cannelton, Indiana; T = Troy, Indiana; L = Lewisport, D = Daviess, Kentucky; E = Evansville,Indiana.

workers on the site, the amount of exposure to fluoride from allpathways (air, drinking water, and soil ingestion) is unlikely tobe great enough to cause skeletal problems. However, ifmaintenance and any construction or remedial workers havecontinuous close contact with surface soil for between 10 and 20years, and their exposure to waste water and sediments wouldexceed EPA's RfD of 0.12 mg/kg/day, their exposure to fluoridemight be great enough to cause skeletal problems. Workers in thepotroom were and are being exposed to fluoride through inhalationof indoor air (Table 6B). However, the amount of fluoridedetected in the potroom air (0.081 - 0.26 ppm or 0.096 - 0.211mg/m3) is far lower than 2.5 mg/m3, which is the REL set byNIOSH, the TLV set by the ACGIH and the PEL set by OSHA. Whileexposure to this low amount of fluoride alone is not likely tocause any skeletal problems even after exposure for between 10and 20 years, some of those workers might also be exposed tofluoride in soil or wastes which could increase the body burden. Therefore, NSA should follow the urinary fluoride monitoringprogram recommended by NIOSH to adequately assess the fluoridebody burden of workers throughout the year.

The estimated amount of fluoride exposure in adults who use thewater systems in Hawesville, Tell City, Cannelton, Troy, EastDaviess, and Evansville does not exceed EPA's RfD of 0.12mg/kg/day that is protective from development of skeletalfluorosis in adults and children 9 years and older (Table 34). Although the estimated fluoride in drinking water at Hawesville,Tell City, Cannelton, Lewisport/ East Daviess, and Evansvilleexceeds EPA's RfD of 0.06 mg/kg/day that is protective fromdevelopment of teeth mottling in children under 8 years old, mostlevels of fluoride in the drinking water do not exceed the 1 ppmlevel at which no adverse effects are observed.

The possibility of people accidentally swallowing river water asthey swim and the small amounts of water accidentally ingested byadults and children from the Ohio River are unlikely to causeeither teeth mottling or skeletal problems.

Lead

Lead exposure has occurred and is occurring in residents in thesite area who have private wells. This is also true forresidents in Hawesville, and, farther away, in Evansville who usepublic water supply, or who swim in the Ohio river.

The exposure to lead from private well water within the vicinityof NSA (0.005 ppm), from the public groundwater water supply atHawesville (0.002 ppm) and from the Ohio River (surface water),is lower than EPA's action level guide of 0.015 mg/L. ATSDR hasno MRLs and EPA has no RfD for lead. Inhaling or ingesting morethan 500 - 1,000 micrograms of lead per gram of soil was a levelpreviously considered by the CDC that could cause elevated bloodlead levels in children. The CDC has since withdrawn thisguideline because of the seriousness of lead exposure amongchildren.

Lead exposure can cause slow growth and learning problems forinfants and young children. Lead exposure is particularlydangerous for unborn children because of the great harm it doesto the developing fetus. Pregnant women exposed to lead can passlead to the unborn children, causing premature birth, low birthweight, and miscarriages. At high levels, lead can damage thebrain and kidneys, raise blood pressure in men, and causeinfertility. Lead acetate and lead phosphate have beendetermined by the National Toxicology Program (NTP), anorganization within the Department of Health and Human Services,to cause cancer in humans. However, that conclusion is based onanimal studies (23, 28). The level of lead in the blood ofexposed people is not known. In the absence of health guidelinesfor comparison, it is not possible to determine whether adversehealth effects could occur even at these low exposure levels.

Manganese

On-site workers at other industries, as well as nearby residentsin Hawesville, Tell City, Cannelton, and Troy, and farther awayin Evansville were exposed and are being exposed to low levels ofmanganese from soil or water (Table 35). While ATSDR has no MRLsfor manganese, the levels of exposure in workers and in residentsdid not exceed EPA's oral RfD for manganese (Table 35). Inaddition, manganese taken orally is only absorbed to a very lowdegree, 3%. However, in iron deficient humans, manganeseabsorption is increased to 7.5%. Alcohol has also been shown toincrease manganese absorption in rats (29). However, manganesefrom the drinking water supplies is unlikely to cause adversehealth effects.

Nickel

Nickel exposure has occurred and is occurring in maintenance andany construction or remedial workers on site and at nearbyindustries and in residents in the NSA vicinity and those whoswim in the Ohio River. While ATSDR has no intermediate andchronic MRLs for nickel, the levels of exposure do not exceedEPA's oral RfD for nickel (Table 36). Moreover, consequences oflong-term exposure to low levels of nickel are not apparent (23, 30). It is therefore unlikely that adverse non-carcinogenic health effects will occur for workers and residents because of




Table 35.

Comparison of Estimated Exposed Dose to Health Guidelines for Manganese
ContaminantExposurePathwayHealth Guideline for Ingestion (mg/kg/day)
ValueSourceExceeded by
Estimated
Exposure Dose
Manganese On-site
SurfaceSoil
0.1RfDNo
ManganeseOff-site
SurfaceSoil
0.1RfDNo
ManganeseOn-site
Private
Well
0.1RfDNo
ManganesePublicWater
Supply,H*, TC*,
C*, T*
0.1RfDNo
ManganesePublicWaterSupply,E*0.1RfDNo
ManganeseSurface
Water(OhioRiver)
0.1RfDNo
* H = Hawesville, Kentucky; TC = Tell City, Indiana; C =Cannelton, Indiana; T = Troy, Indiana; E = Evansville, Indiana.

exposure to low levels of nickel. IARC and the EPA considernickel to be a human carcinogen. However, there is aninsignificant cancer risk associated with the exposure levels.




Table 36.

Comparison of Estimated Exposed Dose to Health Guidelines for Nickel.
ContaminantExposurePathwayHealth Guideline for Ingestion (mg/kg/day)
ValueSourceExceeded byEstimatedExposure Dose
NickelOn-site
SurfaceSoil
0.02 RfDNo
NickelOff-site
SurfaceSoil
0.02RfDNo
NickelSurfaceWater(OhioRiver)0.02RfDNo

Polychlorinated Biphenyls (PCBs)

Maintenance and construction or remedial workers on site havebeen exposed and are being exposed to PCBs from surface andsubsurface soils (Table 37).

The estimated PCB exposure in maintenance and any construction orremedial workers from typical surface soils on site does notexceed ATSDR's chronic MRLs for PCBs. Because of the low levelsof exposure, noncarcinogenic adverse health effects are unlikelyto occur in workers on site. The estimated soil-related PCBexposure in workers that might be in the temporary soil storagearea for a period of 365 days or more would exceed ATSDR's MRLfor PCBs. But the ingestion dose for such an exposure is some1,000 times lower than PCB doses that caused immunologicaleffects in monkeys after 270 days of continuous exposure, andfrom which the chronic MRL is derived (31). However, this estimate is based on the worst case scenario of the maximum levelof PCBs in four samples that NSA said exceeded 10 ppm out of atotal of 19 samples analyzed. In addition, NSA has cordoned thearea and posted signs that warn workers and visitors to stay awayfrom the temporary soil storage area. It is therefore unlikelythat any significant amounts of PCB-contaminated soil havemigrated from the excluded temporary soil storage area. Therefore, workers on site are not likely to suffer any adversehealth effects from exposures.


Table 37.

Comparison of Estimated Exposed Dose to Health Guidelines for PCBs
ContaminantExposurePathwayHealth Guideline for Ingestion(mg/kg/day)
ValueSourceExceeded byEstimatedExposed Dose
PCBsOn-siteSurfaceSoil a 0.000005ChronicMRLNo
PCBsOn-siteSurfaceSoil b0.000005ChronicMRLYes
PCBsOn-siteSubsurface Soil c 0.004Acute MRLYes (Barely)
a = Surface soils elsewhere on site
b = Surface soils in the temporary soil storage area
c = Subsurface soils in foundation excavation at the cooling tower area

The PCB ingestion exposure in the 3-person excavation crew insoils from the foundation excavation at the cooling toweroccurred between January 9, 1992 and February 3, 1992. However,because of some interruptions, the excavation process probablylasted between 2 and 3 weeks. Based on the highest concentrationof PCBs in the excavated soil (Table 7), the acute ingestionexposure in the three persons barely exceeded ATSDR's Acute MRLfor PCBs (Table 37). In addition, the estimated ingestion doseis some 10,000 times lower than PCB doses that caused stomachulcers in experimental pigs after daily exposures for 11 days. The estimated ingestion dose for the three persons is alsoapproximately 100,000 times lower than experimental PCB dosesthat caused 13% decreased survival among experimental rats duringintermediate/subchronic exposure lasting between 2½ weeks (31). It is therefore unlikely that the three persons would suffer anynoncarcinogenic adverse health effects from exposure.

Although the EPA and IARC consider PCBs to be probable humancarcinogens, ATSDR estimates that workers exposed to PCBs insoils from the different locations on site (Table 37) may have noapparent or no increased risk of developing cancer over alifetime.

The potential exposure in the future to PCBs in subsurface soilsat the Dump Pad could be eliminated if any remedial workers orcontractors wear appropriate personal protective equipment andcomply with applicable health and safety guidelines.

B. HEALTH OUTCOME DATA EVALUATION

Health outcome data were not evaluated for this site because ofinsufficient health databases as described in the health outcomedata subsection. In addition, no previous health studies on thepopulation near the site were identified.

C. COMMUNITY HEALTH CONCERNS EVALUATION

We have addressed each of the community concerns about health:

  1. Are the few cases of autoimmune disease (especiallymultiple sclerosis and lupus) reported by one residentwho also suffers from mild form of multiple sclerosis,caused by site-related chemicals?

Although little is currently known about the relationship betweenenvironmental chemicals and autoimmune disease, evidence isgrowing that there is a possible association between the two. Toxicologic evidence shows that several chemicals and drugs(e.g., certain antihypertensives, antiarrhythmics,anticonvulsants, and antimicrobials) and metals (e.g., goldsalts, mercury compounds, and cadmium [in experimental animals])may cause autoimmune responses. For example, patients treatedwith one of the antimicrobials, penicillamine, have developedsyndromes resembling a type of systemic lupus. The toxicologicevidence of a possible association between autoimmune disease andthe salts or compounds of gold, mercury, and cadmium is mainlyexperimental and has been demonstrated only in laboratoryanimals. However, toxicologic evaluation by ATSDR ofcontaminants at the NSA site does not indicate that chemicalsfound there can cause autoimmune disease. Currently, ATSDR isunable to confirm the presence of a cluster of autoimmunediseases in the Hawesville area.

  1. Is it safe to drink water from private and public wellsin the site area?

Sampling of private wells serving nearby Hancock County residentsand workers, as well as sampling of raw or finished water in thelocal public water systems at Hawesville and nearby cities shows low concentrations of contamination within the range seennaturally in some groundwater aquifers elsewhere in the country. In addition, toxicologic evaluation of available data indicatethat adverse health effects are not likely to be seen in peoplewho use those water supplies because of the low levels to whichthey would be exposed. ATSDR believes it is extremely unlikelythat the groundwater serving these private and public watersupply systems is affected by contaminants originating from NSA. However, because some private wells might receive contaminatedflood water or some inflow of contaminated river water, ATSDRrecommended all private wells within one half mile of the siteboundary on the Kentucky side of the river to be sampled at leastannually to verify water quality.

  1. Is it safe to eat meat from livestock and produceraised on farms in the NSA area?

Some contaminants of concern were detected in surface soils offsite. Potential sources of those contaminants include thenaturally occurring chemical constituents in soil, constituentsin flood deposits in low-lying areas, chemicals in farmpesticide/fertilizer applications, and constituents transportedby air from NSA or other sources. However, the contaminants weredetected at low levels and within the range of values detectedelsewhere. Therefore, plant uptake or animal ingestion of soilcontaminants would be expected to be low and not likely to poseany public health threat to residents who eat locally raised meatand produce. However, ATSDR recommended off-site surface soilsto be extensively sampled, especially those adjacent to nearbyresidences and those from fields used for agriculture.

During each month of the growing season, NSA analyzes fluoridecontent of grassy-type vegetation samples taken from alongroadsides across a network of about 50 off-site stations, atdistances ranging up to 8 miles from the property. ATSDRpersonnel examined the laboratory data and discovered that thehighest detected fluoride levels were in vegetation within 1 mileof the site. The presence of apparently elevated fluoride levelsin some grassy vegetation suggests there is a potential for humanexposure. Garden produce raised and consumed by local residentsis of the greatest concern because of the frequency with whichsuch produce would be ingested. However, information is notavailable to determine whether such produce contains fluorides. Therefore, ATSDR recommended garden produce in the immediate sitevicinity to be sampled and analyzed for fluoride and othercontaminants.

  1. Is it safe to live in the NSA area?

The residence nearest the NSA site was observed by ATSDRpersonnel to be about 200 feet southwest of the site perimeter. Three additional homes are within ½ mile west and south of thesite, and up to a dozen more homes were seen within 1 mile--mostly to the west and northwest. In addition, schools, ahospital, a nursing home, and the towns of Cannelton andHawesville are about 1¼ to 3 miles of the site. In order todetermine whether exposure to contaminants in nearby off-siteareas has any public health significance, ATSDR evaluatedavailable environmental data. Samples of surface soils andgroundwater taken from within 100 to 700 feet of the site showedcontaminants within the range of values at which they are foundnaturally in soils and groundwater elsewhere. In addition,exposure to fluoride in ambient air is expected to be low becauseof the small amounts of fluoride detected during the daily andmonthly monitoring of off-site areas. Toxicologic evaluation ofavailable data also indicates that past and current exposures donot pose any public health threat. However, if additional dataand information become available, ATSDR personnel will reevaluateboth the on-site and off-site exposures for any public healthsignificance.


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