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PETITIONED PUBLIC HEALTH ASSESSMENT
FALLS TOWNSHIP GROUNDWATER CONTAMINATION
(a/k/a CORCO CHEMICAL, PARASCIENTIFIC, MEENAN OIL)
FALLS TOWNSHIP, BUCKS COUNTY, PENNSYLVANIA


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

A. CONTAMINATION

ATSDR must rely upon sampling and analysis data developed by others, such as facility ownersand state and federal agencies, for evaluating the nature and extent of contamination. ATSDRhas received sample and analyses information primarily for the Corco Chemical and Meenan Oilrecovery areas and for private wells in the vicinity. No sampling investigations have beenconducted around the building Para Scientific Company leases, except for some soil gasevaluations conducted there by Corco Chemical as a part of its property evaluations. Most of thesampling information received was developed between 1982 and 1985; data for 1986 and laterare quite limited. Essentially all sample analyses were for VOCs. The contaminants mostfrequently detected are several chlorinated compounds: trichloroethane (TCA), TCE, PCE, andchloroform.

Sampling data that provide the framework for the evaluations in this public health assessment aresummarized in discussions that follow. Groundwater, soil, and soil gas data also are summarizedin Tables 1A, 1B, and 1C in Appendix A, along with comparison values ATSDR considered inits evaluation. Sampling data are presented in greater detail in Tables 2-6 (Appendix A). Comparison values for a public health assessment are contaminant concentrations in specificmedia that are used solely to select contaminants for exposure and public health evaluation. Thepresence of a contaminant in a table or its presence at a concentration greater than thecomparison values in Tables 1A, 1B, or 1C does not mean that it will cause adverse healtheffects through exposure. The health significance of contaminants and exposure is described in alater section (Public Health Implications).

Country Lane Trailer Park Water Supply Well

Sample data for groundwater once used for the residents' potable water supply are shown inTable 2 (Appendix A) (9). Chlorinated VOC compounds [TCA, TCE, PCE, dichloroethene(DCE), and chloroform (maximum concentrations from 19-308 ppb)] were detected in thesample as were nonchlorinated VOC compounds like benzenes, xylene, and naphthalenes (25-242 ppb). Five of the compounds were found to be at levels that exceed ATSDR's comparisonvalues for drinking water.

Area-Wide Groundwater

Information about several contaminants found most frequently and at the highest concentrationsat selected private wells within the area is summarized here and in Table 3 (Appendix A).

    Private Wells

Private wells in the study area north of Penn Valley Road are primarily in the followinglocations: on Cedar Lane, on Old Tyburn Road, on the northern portion of Corbin Lane, onBristol Pike, and on the portion of Penn Valley Road east of Bristol Pike. South of Penn ValleyRoad, groundwater users are along or near Bristol Pike. Immediately south of the study area,private wells are along Wheatsheaf Road and near the intersection of Wheatsheaf Road andBristol Pike, south of the canal.

ATSDR has examined one or more sets of groundwater data for 29 private wells in the study areathat were sampled between 1982 and 1992 (2, 3, 9, 10, 11, 12, 13, 14, 15). During the 1990 site visit,ATSDR was shown approximately 40 residences and 15 businesses in the study area that werenot being served with public water. ATSDR assumes most of those locations were being servedby private wells. Thus, it appears not all the wells in the study area have been sampled. By1992, county health personnel report that owners of about 14 of the 29 wells had connected to thepublic water supply, use bottled water, or installed a filter system. However, the effectiveness ofthe treatment systems have not been confirmed. The health department reports that the dataATSDR examined were for untreated well water, except for one treated sample taken in 1990 at aresidence on Corbin Lane.

Most of the 29 wells sampled are north of Penn Valley Road. A few other private wells weresampled along Bristol Pike between Penn Valley Road and the canal. Sampling data also wereobtained south of the study area in 1992 for eight of the private wells that are along WheatsheafRoad and also along Bristol Pike within about 1,500 feet of its intersection with WheatsheafRoad (15).

TCA, TCE, PCE, and chloroform were the principal VOC compounds detected in private wells. The concentrations of those chlorinated compounds in several geographic groups of wells arereported in Table 3. ATSDR's evaluation of the data shows that, of the substantively potentchemicals present, PCE and TCE typically occur together, are the most prevalent, and can beconsidered the primary--but not exclusive--indicators of groundwater quality for this publichealth assessment.

The available data show that the groundwater contamination varies with respect to concentration,location, and time. Sampling conducted between in 1982, 1985, and 1987 for 26 private wellssuggests that well water is least contaminated on Cedar Lane, along Tyburn and Old TyburnRoads, and at the northern end of Bristol Pike. Data also suggest that private well water is mostcontaminated near the intersection of Bristol Pike and Penn Valley Road, an area not close toeither Corco Chemical or the Meenan Oil release locations. More moderate concentrations werenoted in groundwater samples from wells on Corbin Lane and elsewhere on Bristol Pike. Analyses of water from those private wells, excluding the previously described Country LaneTrailer Park well (no longer in use), have shown substantive levels of TCA (625 ppb), TCE(1,400 ppb), and PCE (175 ppb). Eighteen of the 26 wells sampled showed one or more of thosecompounds at levels greater than ATSDR's comparison values for drinking water. Sixteen of thewells contained two or more of those chemicals above comparison values. Chloroform (8 ppb)was also found in a few wells above its comparison value. Nonchlorinated VOC compoundswere detected in only one private well (benzene; 0.9 ppb), except as noted previously for theCountry Lane Trailer Park well.

Sampling was conducted in the study area in 1989, 1990, or 1992 for nine wells. Five of thenine wells contained PCE (20 ppb) or TCE (49 ppb). Three of those five had PCE or TCE atlevels greater than comparison values. The residence at which the greatest concentrations werefound has a filter system; hence, if the filter is performing satisfactorily, the quality of filteredwater should be substantially better than reported for the raw water sample. PCE was present inone of the other two wells at a level of 3.4 ppb, and TCE was present in both at levels as much as13.8 ppb.

Contamination variation over time was reviewed using information for six wells on Corbin Laneand East Penn Valley Road that were sampled one or more times during 1982-1987 and also1989-1992. Those data show that maximum total TCE and PCE concentrations present in eachof those wells during the 1982-1987 period were substantially lower during the 1989-1992period. Examples of total TCE and PCE decrease over time include; 29 ppb decreased to notdetected, 32 ppb decreased to 0.7 ppb, and 1,575 ppb decreased to 69 ppb. Many of the other 26wells sampled during 1982-1987 were not resampled later and, hence, provide no insight tocontamination variation with time. The 1982-1987 data showed some wells that were notresampled contained no TCE or PCE, some contained TCE or PCE below ATSDR's comparisonvalues, and some contained TCE or PCE at levels greater than comparison values.

ATSDR also reviewed the latest available sampling data for each of the 29 wells tested toidentify current water quality at wells that continue to be used for potable water. Results of thisevaluation suggest 4 wells in use contained contaminants, when last tested, at levels that exceedATSDR's comparison values; 1 well in use contains contaminants that would exceed ATSDR'scomparison values if the filter system does not function properly, and 1 well containscontaminants that exceed comparison values but current use of the well is not known.

The areal distribution of contaminants shown in well data was evaluated to assess whether theexisting sampled well locations might adequately circumscribe and characterize groundwatercontamination within the study area and provide confidence about water quality at locations thathave not been sampled. This evaluation provided two examples from the 1985 and 1987sampling data that show that evidence of acceptable water quality at one private well locationdoes not necessarily mean that water quality at an adjacent well can be assumed to be acceptable;1) One deep well near East Penn Valley Road showed no contamination, while two nearbyshallow wells showed substantially elevated levels, and 2) two deep wells on Bristol Pikeshowed no contamination, while a nearby well (depth unknown) between the two showedunacceptable levels of contamination. From this information, ATSDR concludes that thecharacter of groundwater identified at the specific wells sampled may not be indicative ofgroundwater quality nearby or elsewhere in the study area.

    Non-drinking Water Wells

Groundwater data are available for the Corco Chemical monitoring wells (Tables 3 and 4) andfor the Meenan Oil recovery well system (Tables 3 and 5) (2, 3, 4, 12, 14, 16, 17, 18, 19, 24, 26). Several contaminants were found at levels that exceed ATSDR's comparison values for drinkingwater. Elevated concentrations of the principal chlorinated VOCs [TCA (350 ppb), TCE(3,700 ppb), PCE (1,200 ppb), and chloroform (1,880 ppb)] were detected in groundwater at theMeenan Oil fuel recovery well system near Cedar Lane. The compounds also were detected atCorco Chemical monitoring wells. Levels were low at the Corco wells in earlier years, but,according to the most recent data, concentrations have increased [TCA (25 ppb), TCE (214 ppb),PCE (431 ppb), and chloroform (77 ppb)]. Groundwater at the Meenan Oil recovery well systemalso was found to contain elevated, nonchlorinated VOCs [benzene (778 ppb) and toluene(356 ppb)]. Nonchlorinated VOC levels at the Corco Chemical monitoring wells are much lower[benzene (3 ppb), toluene (6 ppb), xylene (17 ppb)]. Lead (50 ppb) also was reported ingroundwater at one Corco monitoring well during one sampling. Low levels of carbontetrachloride (10 ppb) and dichloroethane (DCA) (5 ppb) were detected at both locations.

Corco Chemical Samples

Detailed sampling data for Corco Chemical are shown in Table 4 (Appendix A). Groundwaterinformation was summarized previously in the Area-Wide Groundwater section of this publichealth assessment. Analyses of samples from the company's potable water supply well through1985 showed low levels of VOCs (3, 14). TCE (5 ppb in 1982; <1 ppb in 1985) had the highestconcentration; the TCE level reported in 1982 slightly exceeds ATSDR's comparison value fordrinking water; the concentration in the 1985 sample is below its comparison value. The countyhealth department reports that well is still in use.

Analyses of lake water west of the plant property showed low levels of two chlorinated VOCs(TCA and TCE); TCA was of greater magnitude (2 ppb) (3, 14, 19). TCE (1.6 ppb) was present atvalues slightly below ATSDR's comparison value for drinking water.

The cooling water effluent that discharges into the lake east of Cedar Lane was analyzedfrequently through early 1990. Many contaminants have been detected in the effluent. Somerange greatly in magnitude over time; the highest levels generally occurred in the earlier years(3, 20). The highest concentrations were noted for chlorinated VOCs, such as TCE (>1000 ppb),PCE (>500 ppb), and chloroform (>500 ppb); those levels are well above ATSDR's comparisonvalues for drinking water. Nonchlorinated compounds included xylene (120 ppb). Now thatdrains have been disconnected from the cooling water system, contaminant levels in its effluentprobably are minimal. However, sampling data are not available to confirm that.

Water samples taken at the lake east of Cedar Lane showed low levels of three chlorinated VOCs[TCE (2.9 ppb), PCE (3.4 ppb), and chloroform (1.1 ppb)] and a nonchlorinated VOC, toluene(4 ppb) (4, 14, 21). Lead also was detected (3.0 ppb). Of these, the PCE level exceeds itscomparison value for drinking water, and TCE was about equal to its comparison value. Analyses of sediments from the lake showed low levels of four VOCs. DCE was at the highestlevel (10 ppb), and TCE and PCE also were present (21). Now that the cooling water effluent nolonger contains drain discharge, lake contaminant levels might be lower than shown by theavailable data.

Soil gas analyses were conducted in 1989 at shallow depth below ground at the plant area, nearthe building leased by Para Scientific Company, on the east edge of Cedar Lane, and east ofCedar Lane near the landfill (22). At the plant area, the principal chemicals detected includedTCE, PCE, benzene, and toluene at levels ranging from 130,000-340,000 ppb, by volume. At theeast edge of Cedar Lane and by the Para Scientific building, TCE and PCE were the primary soilgas constituents at levels of 50,000 ppb, by volume. By the landfill, PCE was detected at a levelof 300 ppb, by volume. The concentrations of benzene, PCE, and TCE exceed ATSDR'scomparison values for chronic exposure in ambient air. Benzene, PCE, TCA, and toluene levelsexceed comparison values for acute exposure in ambient air. Sampling data are not available foroutdoor ambient air or for interior air (businesses and residences).

Surface soil (depth to 12 inches) was sampled at the plant area (21, 26). VOCs were essentiallyabsent in the soils, but several other contaminants were detected, including polychlorinatedbiphenyls (PCBs) (5,300 ppb), bis(2-ethylhexyl)phthalate (1,200 ppb), and low- andhigh-molecular-weight polynuclear aromatic hydrocarbons (PAHs) (1,154-1,674 ppb). Theconcentration of PCBs exceeds ATSDR's comparison value for incidental soil ingestion. Analysis of a background soil sample showed PAHs at slightly lower concentrations than thoseof samples taken on the property.

A solvent trap and junction box were sampled several times before the system was disconnected(22, 23). The trap was removed, and the box was cleaned. Sampling in 1989 showed manycontaminants, including TCA, TCE, PCE, and chloroform (8,647-12,334 ppb) and acetone(107,801 ppb). The level of PCE exceeds ATSDR's comparison value for incidental ingestion.

Meenan Oil Recovery System Samples

Detailed sample data for the Meenan Oil recovery system are shown in Table 5 (Appendix A). Groundwater analyses associated with this system are summarized previously in the Area-WideGroundwater section of this public health assessment.

Effluent from the recovery system that discharged groundwater to Warner Lake, south of PennValley Road, also showed elevated levels of chlorinated compounds (TCE, PCE, chloroform,DCE, and DCA [1,600 to 4,500 ppb]) (4, 19, 24). Sampling showed that the effluent alsocontained benzene (778 ppb). Several compounds exceed ATSDR's comparison values fordrinking water.

Analysis of a water sample from Warner Lake taken in 1986 while effluent was being receivedshowed chlorinated compounds were present, but at much lower concentrations (16-153 ppb)than were found in the recovery well effluent (4). The greatest concentrations were of DCE,DCA, and PCE. Nonchlorinated compounds, benzene (191 ppb) and toluene (2.4 ppb), also werepresent. Several compounds were at levels that exceed ATSDR's comparison values for drinkingwater. Water quality in the lake is likely to be substantially better now that the recovery activitieshave terminated. However, recent sampling data are not available to confirm that.

Samples of surface soils from the vicinity of the recovery well and from elsewhere withinPennwood Crossing were analyzed; no organic compounds were detected (4).

K-Mart Samples

Data for several samples of water that pooled on the K-Mart property and in ditches in 1982during attempts to put out the K-Mart fire are shown in Table 6 (Appendix A) (10). VOCs weredetected in only one sample. Primarily chlorinated compounds, including TCA (330 ppb), werepresent; benzene (30 ppb) also was detected. The concentrations of both compounds exceedATSDR's comparison values for drinking water.

The results of groundwater monitoring at K-Mart in 1983 also are shown in Table 6 (25). Analyses were not performed for VOCs. Pesticides and PCBs, the only organic compoundsanalyzed for, were not detected.

B. QUALITY ASSURANCE AND QUALITY CONTROL

ATSDR has received little quality assurance information for laboratory analyses and none forfield sampling. In preparing this assessment, ATSDR has presumed that appropriate protocolswere followed and that analytic results are valid. The completeness and reliability of availableinformation could affect the validity of ATSDR's conclusions.

C. PHYSICAL AND OTHER HAZARDS

ATSDR observed nothing in the area of concern that should pose a usual type of physical hazardto the public. Soil gases could be hazardous if VOCs are released below ground fromcontaminated groundwater or subsurface chemical wastes, migrate into buildings, andaccumulate at explosive levels. Ambient air monitoring data are not available, and informationabout soil gases is not sufficient to fully evaluate whether a hazard exists.

PATHWAYS ANALYSES

A. ENVIRONMENTAL PATHWAYS (FATE AND TRANSPORT)

Chemicals can enter the environment from a source as a result of a planned or permitted releaseor an accidental release to the ground, air, surface water or sediment, groundwater, and,sometimes, plants and animals. In an active workplace, contaminants can be transported byproduction and maintenance activities, vehicle traffic, or construction. Workers may transportcontaminants on their clothing and skin. Once in the environment, contaminants may begin todegrade or migrate depending on climatic factors, physical factors associated with the releasesetting, chemical factors associated with the contaminant, and factors associated with thereceiving environmental media. VOCs, which were detected primarily in groundwater, surfacewater and soil gas at the Falls Township site, are highly volatile, and most are relatively mobilein soil and water. The phthalate, PAHs, and PCBs found in soils at Corco Chemical, are onlyslightly volatile and relatively immobile in soil and water. Substantial sampling and analytic datausually are required to confirm the actual source(s) of contaminants and the environmental mediathat are important transport pathways.

Information about several potential sources of the observed groundwater contamination havebeen considered in the course of this public health assessment: Corco Chemical, Para ScientificCompany, the Meenan Oil fuel leak, the landfill, the K-Mart fire, septic system cleaners, andtrucking companies. The absence of comprehensive sampling over time and uncertainty aboutgroundwater flow patterns probably preclude identifying any primary, or dominant, source ofeither the chlorinated or nonchlorinated VOCs. For example, available data show the highestlevels of chlorinated VOCs have been found in private wells near the junction of Penn ValleyRoad and Bristol Pike. Those findings suggest that either a separate unknown source in thevicinity released contaminants to groundwater, or a mass of more highly contaminatedgroundwater from another source migrated there.

Groundwater is relatively shallow (10-20 feet), and water levels in the lakes probably reflect theapproximate groundwater table elevation throughout the area of concern. Soils beneath the areaare primarily sand and gravel and extend well below the groundwater table. Because soils aresandy, the permeability and groundwater flow rate in some soil zones could be relatively high. The general direction of groundwater flow in the region is likely to be toward the DelawareRiver, which is within about a mile to the east of the area and somewhat farther away to thesoutheast and south. Some investigators suggest that flow direction in the immediate area is eastand southeast, toward Van Sciver Lake (2). However, the specific effects of local topography,geology, and the temporary fuel oil recovery activities on groundwater flow across the area arenot defined.

VOCs possibly migrated to groundwater by percolating downward through soils following spills,leaks, septic tank discharge, and pooling of water used to put out the K-Mart fire. Surface waterin the lake east of Corco, which receives the chemical company's effluent, probably is a source ofgroundwater recharge; therefore, some contaminants released by Corco to the lake could enterthe groundwater system. Also, VOCs or other contaminants that might be in landfilled materialsor oil reclamation residues next to the lake might enter area groundwater by percolation throughsoil or by runoff into lake water. Surface runoff from Corco Chemical into the lake to its westcould also transport contaminants that would subsequently enter the groundwater throughrecharge by lake waters. The layer of fuel oil that floated on groundwater at the Meenan Oil fuelleak prior to cleanup undoubtedly resulted in direct migration of some nonchlorinated VOCs, andprobably soluble fractions of non-VOCs, to groundwater. Information is insufficient to showwhether any VOCs contributed by the fuel oil release to groundwater migrated to any privatewells. Clean-up operations included discharge of contaminated groundwater to Warner Lake,where some portion of the diluted discharge might enter the groundwater system throughrecharge by lake water. Runoff from the K-Mart fire might have transported chemicals fromthere to the Delaware River via a creek that passes well west of the area of concern.

VOCs in contact with ambient air tend to volatilize and migrate as a gas to surrounding areas. The principal sources of airborne VOCs are likely to be from workplaces and from spills ordisposal on the ground. Volatilization could also occur readily from contaminated water in arealakes. If chemical releases lessen or stop, continued volatilization usually decreases theconcentrations of source chemicals on the ground and in lakes. VOCs present below the groundsurface because of waste burial or percolation and VOCs transported by groundwater also willvolatilize. The resulting soil gas occupies voids in the soil matrix and may move along verticalor horizontal paths toward areas of lower pressure. Some soil gas may exit the ground surfaceand become diluted in ambient air; it also may exit to buildings where gases could accumulate inenclosed space.

Non-VOCs (for example, phthalate and biphenyls) detected in soil at Corco Chemical tend tosorb strongly to the soil. Therefore, if contaminated soil erodes and runs off to the adjacent lake,the compounds could become part of the sediment. Another migration mechanism for thecompounds may be suspension of contaminated particles by wind, vehicle, or worker activity andsubsequent wind transport and deposition elsewhere to the groundwater or lake waters.

If non-VOC compounds detected in soils at Corco Chemical are in water or sediments in theadjacent lake, they may bioaccumulate in fish. The VOCs known to have been in area lakewaters do not bioaccumulate substantively in fish. Likewise, VOCs found in groundwater wouldnot tend to be taken up in garden produce irrigated with contaminated water.

B. HUMAN EXPOSURE PATHWAYS

ATSDR identifies completed and potential human exposure pathways by examiningenvironmental and human components that lead to contact with contaminants. A pathwayanalysis considers five elements: a source of contamination, transport through an environmentalmedium, a point of exposure, a route of human exposure, and an exposed population. Acompleted exposure pathway exists when all five elements are evident and indicates thatexposure to a contaminant has occurred, is occurring, or will occur. A potential exposurepathway exists when one or more of the five elements is not clearly defined but could be present. Potential pathways indicate that exposure to a contaminant is plausible and could have occurred,could be occurring, or could occur.

ATSDR's pathway analyses indicate that residents' and workers' use of contaminatedgroundwater is a completed exposure pathway in portions of the study area. Analyses also showthat residents' or workers' activities associated with surface water, sediment, air, soil gas, and soiland their workplace are plausible potential exposure pathways.

Completed Exposure Pathway

    Groundwater

Available information about groundwater sampling and well use indicates that during the early1980s some of the persons in the study area that have relied on private wells for their potablewater supply were exposed to substantive concentrations of VOCs in the groundwater. In 1990,ATSDR was shown the locations of approximately 40 residences and 15 businesses in the studyarea that relied on groundwater. The sampling data for 29 wells shows that most, but not all ofthe wells tested had contaminated water. Review of the latest available test data for each of the29 wells that are still used for potable water suggests that 4 contain VOCs that exceed ATSDR'scomparison values for selecting contaminants for exposure and public health evaluation and 1contains VOCs that would exceed comparison values if the filter system malfunctions. Anadditional well contains VOCs that exceed comparison values, but current use of the well isuncertain. ATSDR believes the available data cannot be extrapolated with confidence tocharacterize water quality at unsampled well locations; hence groundwater for some other pastand currently used wells in the study area that have not been sampled might also be contaminatedat levels that exceed ATSDR's comparison values.

The water authority reports that by the end of 1992 more private well users in the study area hadconnected to the public water supply.

The primary exposure routes of concern for well users are ingestion of contaminated groundwater(drinking water and food) and inhalation (showering, bathing, and cooking). In residences wherecontaminated water is used for domestic purposes, such as showering and cooking, as well asdrinking, the amount of exposure to VOCs through inhalation can be about as great as theexposure that occurs from drinking. Dermal contact is a less important exposure route.

Potential Exposure Pathways

    Groundwater Pathway

Workers at the Meenan oil recovery well might have been exposed to VOCs while installing orremoving equipment or from recovered groundwater and oil, primarily through inhalation anddermal contact.

    Surface Water and Sediment

People who swim, boat, or fish in nearby lakes might be exposed intermittently to VOCS,probably at low concentrations, primarily through incidental ingestion and inhalation if the waterhas been contaminated by chemicals in groundwater influent or by chemicals in industrial-typedischarges. Potential exposure issues cannot be fully evaluated because sampling data either arenot available, are too old, or are of insufficient quantity to determine whether water at any of thelakes presently contains contaminants at levels of concern. PADER reported to ATSDR theycontacted various agencies in 1992 and could not determine whether nearby lakes are used forrecreation--except for Van Sciver Lake which is used for swimming, boating and fishing. Anarea resident reported to ATSDR in 1990 that swimming and fishing had been observed in thepast in the lake east of Corco Chemical and swimming had been observed in Warner Lake. Warner Lake is well posted in 1992 and appears to be quite shallow; thus, that lake may beunattractive for recreation in the future.

Two lakes that received industrial-type discharges are of primary interest. Relatively highconcentrations of VOCs had been discharged over time from Corco Chemical to the lake to itseast and from the Meenan Oil recovery well to Warner Lake. The reported lake waterconcentrations are much lower than the concentrations in the discharged materials because of thediluting effect of the large volume of receiving water and because of their continuingvolatilization from the receiving water. Also, the major contaminant sources have beeneliminated; Corco Chemical eliminated key sources of VOCs from its cooling water discharge,and Meenan Oil stopped its oil recovery operations. Very low levels of VOCs also have beenrecorded in the lake water west of Corco Chemical, the company's source of cooling water. Thus, the cooling water discharge is likely to transfer those VOCs unabated to the lake east ofCorco.

Investigators suggest that locally, groundwater flows east and southeast toward Van Sciver Lake. Sampling information is not available for Van Sciver or lakes other than those previouslydescribed. However, contaminant levels would likely be low in Van Sciver Lake, and at any lakeinto which contaminated groundwater discharges, because of dilution and through volatilizationof VOCs from the water to the atmosphere. The same would hold for any lake into whichcontaminated groundwater might discharge. However, actual water quality in the lakes has notbeen confirmed. The large lake that is west and southwest of the lake from which Corco drawsits cooling water is posted along Penn Valley Road, which may inhibit its use for recreation.

Swimmers or waders may be exposed intermittently to contaminants in sediments in some lakesduring such activities, primarily through incidental ingestion. Also, if sand and gravel removal isre-initiated at an affected lake, workers could be exposed intermittently to contaminantsprimarily through incidental ingestion and inhalation of contaminated particles. Sedimentsamples, obtained only at the lake east of Corco Chemical, contained low levels of VOCs. Sediments at Warner Lake could contain some VOCs because of the Meenan Oil discharge. Because the major contaminant sources at those two lakes have been eliminated, the currentconcentrations of VOCs in sediments may not be consequential. Sediments at Warner Lake alsomay be contaminated with non-VOC compounds from the Meenan Oil recovery operation, andthe lake sediments west of Corco Chemical may be contaminated with PAHs or PCBs fromrunoff at that property. Runoff from the landfill to the lake east of Corco also may have releasednon-VOC contaminants to the sediments. Sampling data are not available to confirm whethersuch contamination exists.

Water used to put out the K-Mart fire produced water shown by analysis to contain low levels ofa few VOCs. No pesticides or herbicides were detected. Because of the diversity of productsstored, however, some non-VOCs probably also were contained in and transported by runoff,principally as residue of the burned materials or bound to soil particles. Runoff waters werecarried from the area by a drainage system that ultimately discharges into the Delaware River. Runoff may have deposited chemicals as sediment along the drainage route and discharged othersinto the river.

The brief exposures that might have occurred to the low levels of VOCs in runoff water areunlikely to have been a health concern. Data are not available to evaluate what types of non-VOCs may have been in the runoff water; hence, exposure effects of non-VOCs, if any, cannotbe evaluated. Therefore, the K-Mart runoff water is not addressed further in this public healthassessment.

    Air and Soil Gas

People could be exposed by inhalation to VOCs in ambient air in the workplace, and, possibly, inresidences, but such exposure is less likely outdoors, where substances are rapidly diluted. In theworkplace and at the landfill, people also might be exposed by inhalation to airbornecontaminated particulates. Issues potentially associated with ambient air and soil gas cannot befully evaluated because air monitoring data are not available, and soil gas and groundwater dataare too limited.

VOCs in contaminated groundwater will tend to volatilize when well water is used in residencesand businesses and will accumulate in indoor ambient air. Occupants at such locations would beexposed through inhalation. ATSDR's experience also shows that soil gas released from VOCsin contaminated groundwater and soil can enter residential and business structures andaccumulate. Sampling near Corco Chemical has shown high concentrations of soil gas belowground on their property and diminished levels at the landfill, the farthest location evaluated. Ifsoil gas does enter buildings, occupants would be exposed to contaminants through inhalation. At high concentrations, some types of gases conceivably might explode and cause physical harm.

    Soil

Workers outdoors at Corco Chemical, potentially have been exposed intermittently tocontaminants in soil, primarily through incidental ingestion or inhalation of contaminatedparticles. If soil contamination found around the Corco buildings extends as far as the ParaScientific building, any workers outside that building potentially could be exposed intermittentlyto contaminants in that medium. Likewise, if soils around the landfill contain contaminants,former workers there potentially were exposed intermittently through incidental ingestion andinhalation. Results of sampling conducted throughout the Pennwood Crossing area show that theMeenan Oil recovery operations did not contaminate surface soils. Thus, residents there shouldnot be exposed to the chemicals of concern through the soil medium.

The K-Mart fire could have resulted in substantial residual soil contamination. If so,construction workers for the new building and grounds and maintenance workers potentially havebeen exposed intermittently, primarily by incidental ingestion or inhalation. No soil samplingdata are available to evaluate those issues. Therefore, the K-Mart soil is not addressed further inthis public health assessment.

    Biota

Residents who consume garden produce irrigated with contaminated groundwater are not likelyto be substantively exposed to the chemicals of concern because plants generally do notbioaccumulate VOCs. Although fish generally do not bioaccumulate VOCs in surface watereither, they can bioaccumulate some non-VOCs through water and the foodchain. Thus,compounds such as the PCBs found at low levels in surface soils at Corco Chemical might havereached lake water and sediments west of the plant and been taken up by fish. Therefore, personswho consume fish from that lake might be exposed intermittently to selected non-VOCs thathave bioaccumulated in edible tissue. Information about non-VOCs in that lake (and other lakes)and about fish consumption are not available to fully evaluate potential exposures.

    Chemicals and Oil in the Workplace

Past and current workers at Corco Chemical, if they have not been adequately protected, mayhave been exposed intermittently through inhalation, dermal contact, or incidental ingestion tocontaminants while processing or re-packaging chemicals. Para Scientific workers are not likelyto be exposed in the workplace unless a substantive breakage occurred. Worker's safety- andhealth-related activities at active facilities like Corco Chemical and Para Scientific Company aresubject to regulation by the U.S. Occupational Safety and Health Administration. Workers at theMeenan Oil recovery well and the closed landfill and possibly its oil reclamation unit also mighthave been exposed intermittently to a variety of chemical compounds in oil or in wastes. Truckmaintenance workers also may have been exposed intermittently to contaminants from oil andvarious chemicals. Unless workers have exercised exceptional care, some chemicals could havebeen transported to their homes via clothing, and, in turn, family members may have beenexposed intermittently by dermal contact, inhalation, or incidental ingestion. Information aboutpast or present work practices and related sampling data for the locations identified are notadequate for determining whether potential exposures are of concern.

PUBLIC HEALTH IMPLICATIONS

Some citizens may be or may have been exposed to hazardous substances in groundwater at theFalls Township study area. Exposures may result from ingestion of contaminated water used fordrinking or cooking; from inhalation of and dermal contact with contaminated water used forshowering or bathing; or a combination of these routes. Contaminants of concern in thegroundwater include PCE, TCE, and chloroform. As is further discussed in the Health EffectsBy Contaminant section of the Toxicologic Evaluation section below, chronic (long-term)exposures to those contaminants through drinking water may be a public health hazard; acute(short-term) exposures via drinking water pose no apparent public health hazard. Exposure to1,1,1-trichloroethane through drinking water is at a level below public health concern. Exposureto benzene through drinking water is at a level below public health concern, but exposure to anyhuman carcinogen such as benzene should be limited.

In addition, persons who use lakes (for swimming, boating, wading and fishing) to whichgroundwater has transported contaminants might also intermittently have been exposed, byincidental ingestion, inhalation, and dermal contact to 1,2-dichloroethane (1,2-DCA). Individuals who have swum regularly (more than once per week) in the lakes may have beenexposed to 1,2-DCA at a level of public health concern. Without additional information aboutfish consumption habits and levels of contaminants in fish, ATSDR cannot evaluate the healthrisk associated with fish consumption, although VOCs such as 1,2-DCA are not expected tobioaccumulate in fish. Using the reference dose developed by EPA for contaminants, ATSDRstaff members have determined that there is no apparent public health hazard to people using thelakes for other activities.

Workers at Corco Chemical may have been exposed to polycyclic aromatic hydrocarbons (PAHs)and polychlorinated biphenyls (PCBs) in soil around the facility. Further characterization ofcontaminant location in relation to occupational activities is necessary to identify whether anexposure of health significance is occurring or may have occurred.

Because Corco Chemical property is an occupational rather than a residential setting, the public'saccess to the soil may be limited. Based on the information provided, any current exposuresassociated with the soil do not appear to represent a health threat based on short-term exposure. The level and extent of soil contamination, as well as worker activity patterns, must be evaluatedto determine whether there is a health hazard based on long-term exposure. Therefore, workerspotentially exposed to contaminants in soil around Corco Chemical are not discussed further inthis public health assessment.

A. TOXICOLOGIC EVALUATION

ATSDR staff have examined the available scientific literature on various adverse health effectsassociated with exposure to site-related contaminants. The adverse health effects are broadlygrouped as cancer and non-cancer. Following is a brief discussion of adverse health effects ingeneral followed by discussions of health effects associated with exposures to specificcontaminants of concern by way of potential and completed pathways.

Cancerous and Non-cancerous Health Effects

Cancer is a group of diseases characterized by uncontained growth and spread of abnormal cells. Cancer cells multiply uncontrollably, destroying normal cells, and can spread from their site oforigin to other parts of the body (27). A chemical capable of causing damage leading to cancer iscalled a carcinogen. The latency period, or amount of time between exposure and developmentof disease, ranges from a few years to decades (28). One contaminant of concern at the FallsTownship study area, benzene, has been classified as a human carcinogen, a designation given tochemicals for which sufficient experimental evidence indicates its ability to cause cancer inhumans. Several contaminants of concern, including PCE, chloroform, and 1,2-DCE, have beenclassified as probable human carcinogens--chemicals shown experimentally to cause cancer inanimals. There is inadequate evidence on their human carcinogenicity; but, based on a lifetimeexposure, they are suspected of causing cancer in people. One other contaminant of concern,TCE, has inconclusive evidence of causing cancer in animals or people. ATSDR estimatescancer risks by using the EPA's Cancer Potency Factor. That method assumes that animal datagathered under high-dose exposure conditions can be used to estimate the risk of low-doseexposures in humans (29). The method also assumes that there is no safe level of exposure (30). There is little experimental evidence to confirm or refute those two assumptions. Lastly, themethod computes 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 by several orders ofmagnitude (31).

Chemical exposure may result in adverse health effects other than cancer. Those effects may beacute (resulting from a short-term exposure of less than 14 days), intermediate (resulting from anexposure of more than 14 but less than 365 days), or chronic (resulting from an exposure of atleast a year's duration). ATSDR has developed Minimal Risk Levels (MRLs) for use as healthcomparison guidelines of contaminant exposure. An MRL is an estimate of daily humanexposure to a chemical likely to be without an appreciable risk of deleterious non-cancerouseffects over a specified duration (acute, intermediate, or chronic) of exposure. The merepresence of a contaminant does not imply that harm will result from exposure. A contaminant ata concentration lower than that chemical's MRL should pose no appreciable public health hazardwith respect to non-cancerous adverse health effects.

Health Effects by Contaminant

Tetrachloroethylene (PCE)

Contaminated well water users may ingest tetrachloroethylene (PCE) and inhale PCE which hasvolatilized. The maximum level detected at this study area was 175 ppb (in a private well). PCEis a probable human carcinogen because animal studies indicate it is an animal carcinogen;however, available information is not adequate to determine whether exposure to PCE may beassociated with cancer in people (32). ATSDR estimated the cancer risk associated withexposure to tetrachloroethylene at the Falls Township study area. We have determined that thereis a low to moderate increased cancer risk, depending on the level of contamination in the welland on the length of time residents drank the contaminated water. Recent information indicatesthat PCE levels may have declined significantly in some private wells and is no longer adding tothe cancer risk. However, other wells in the area have not been sampled and may contain levelsof PCE that could be increasing the risk of cancer.

The maximum PCE concentration detected in the well water is below the ATSDR MRL forintermediate exposure via ingestion. Therefore, noncancerous adverse health effects would notbe expected. ATSDR has not developed an MRL for chronic ingestion of PCE.

Limited information about the effects of acute exposure to PCE in people indicates that thecentral nervous system, liver, and kidney may be affected (32). Information on the exposurelevels associated with those effects is inadequate, however, those levels are several orders ofmagnitude higher than those associated with the study area.

Indoor air concentrations of PCE were not measured. They are likely to be significantly lowerthan levels experimentally shown to be associated with adverse health effects in humans andanimals (32). Inhalation exposure could contribute to an individual's total exposure to PCE.

Trichloroethene (TCE)

Contaminated well water users may ingest trichloroethene (TCE) and inhale TCE which hasvolatilized. The maximum level detected at this study area is 1,400 ppb (in a private well).

TCE is considered a possible to probable human carcinogen; EPA has not conclusivelydetermined TCE's cancer classification.

Increased incidences of tumors have been observed in some animals experimentally exposed toTCE by ingestion or inhalation. Some laboratory studies indicate that some mice exposed toTCE by ingestion developed liver cancer. Additional studies in mice suggest that inhalation mayresult in liver and lung cancer. Some of the TCE studies use questionable methods and haveinconclusive results, making it difficult to determine TCE's "true" carcinogenicity (33). ATSDRused available data to estimate the increased cancer risk associated with exposure to TCE at theFalls Township study area. We have determined that there is a low to moderate increased cancerrisk, depending on the level of contamination in the well and on the length of time residentsdrank the contaminated water. Recent information indicates that TCE levels may have declinedsignificantly in some private wells and is no longer adding to the cancer risk. However, otherwells in the area have not been sampled and may contain levels of TCE that could be increasingthe risk of cancer.

The maximum TCE concentration detected in well water at the study area is below the ATSDRMRL for intermediate exposure by ingestion. Therefore, noncarcinogenic adverse health effectswould not be expected. ATSDR has not developed an MRL for chronic ingestion of TCE.

Indoor air concentrations of TCE were not measured. They are likely to be significantly lowerthan levels experimentally shown to be associated with adverse health effects in humans andanimals (33). Inhalation exposure could contribute to an individual's total exposure to TCE.

Chloroform

Contaminated well water users may ingest and inhale chloroform. The maximum level detectedat the study area was 142 ppb (in a private well).

Epidemiologic studies indicate a possible relationship between exposure to chlorinated drinkingwater and cancer of the bladder and large intestine and rectum in people (34). Chloroform is oneof several VOCs frequently found in chlorinated drinking water that is considered to havecarcinogenic potential, but it has not been identified as the sole or primary cause of excess cancerrates associated with chlorinated drinking water. Although available information is not adequateto determine whether exposure to chloroform may be associated with cancer in people,chloroform is a probable human carcinogen because animal studies indicate it is an animalcarcinogen (34). Mouse studies indicate that ingestion of chloroform may result in liver cancer. Additional studies in rats suggest that ingestion may result in cancer of the kidney. ATSDRestimated the cancer risk of exposure to chloroform at the Falls Township study area. Themaximum levels of chloroform found here may represent a slightly increased risk of cancer foranyone ingesting the water regularly for many years. Long-term oral exposure to chloroformmay cause damage other than cancer to the liver and kidney.

The maximum chloroform concentration detected in the well water is below the ATSDR MRLfor chronic exposure by ingestion. Therefore, noncancerous adverse health effects would not beexpected.

Indoor air concentrations of chloroform were not measured. They are likely to be significantlylower than levels experimentally shown to be associated with adverse health effects in humansand animals (34). Inhalation exposure could contribute to an individual's total exposure tochloroform.

Benzene

Contaminated well water users may ingest benzene and may inhale benzene which hasvolatilized. The maximum level detected at the study area was 18 ppb (in a private well). Because numerous studies indicate that occupational exposure to benzene may be associated withan elevated incidence of leukemia, benzene has been classified as a human carcinogen (35). Those studies involved inhalation exposures; no studies have been found of cancer effects inpeople after oral exposure to benzene. Animal studies indicate oral exposure to benzene maycause cancer (35). ATSDR estimated the risk of cancer from benzene ingestion at this studyarea and concluded that the maximum levels of benzene found may represent a slightly increasedrisk of cancer for anyone ingesting the water contaminated at this level over a lifetime. Sincerecovery wells closed approximately 10 years after the spill was detected, ATSDR estimated therisk of cancer from benzene ingestion over a 10 year period and found no increased risk ofcancer.

Studies addressing adverse health effects in people who have been chronically exposed to thelevels of benzene associated with the study area were not found. Clinical effects associated withpeople who ingested benzene once have been reported (35, 36). In those reports, theconcentrations of benzene were not noted, but estimated exposure doses were several orders ofmagnitude (an order of magnitude is 10 times) higher than exposure doses estimated to resultfrom ingestion of benzene-contaminated water at the Falls Township study area. Effectsfollowing ingestion included coughing, stomach pain, nausea, vomiting, and adverse centralnervous system effects. Additionally, studies with rats and mice indicate that chronic exposureto low levels of benzene is associated with adverse immunologic effects (35). Although thebenzene levels in those experiments were low, they were still several orders of magnitude higherthan levels associated with this study area. ATSDR does not expect adverse health effectsrelated to benzene exposure at this study area.

1,2-Dichloroethane

Frequent swimmers in contaminated lakes may intermittently ingest and inhale 1,2-dichloroethane. The maximum level detected at the study area was 109 ppb (in lake water).

1,2-Dichloroethane (1,2-DCA) is a probable human carcinogen. Available information isinadequate to determine whether long-term exposure to 1,2-DCA in people may cause cancer(37). Mouse and rat studies indicate several tumor types were associated with exposure to 1,2-DCA (38). Cancers in experimental animals were noted at dosages several orders of magnitudehigher than most persons using contaminated water in Falls Township would be expected toreceive or have received. Swimmers may have been exposed during contact with the water ofWarner Lake; however, ATSDR is not aware of any individuals who swim in Warner Lakeregularly. In addition, not enough samples have been analyzed to determine the spatial andtemporal patterns of lake water contamination. Because of the lack of information, health effectsassociated with swimming exposures cannot be evaluated, but ATSDR expects those exposuresto be below levels of health concern. Individuals using the lake for other purposes (e.g., boating)would not have received a significant exposure.

B. HEALTH OUTCOME DATA EVALUATION

ATSDR has identified health outcome data (cancer incidence and mortality rates) for BucksCounty and the state of Pennsylvania; ATSDR also has identified an investigation of a reportedcancer cluster in Falls Township being conducted by the State Cancer Control Program. Finally,ATSDR has received and reviewed medical records from individuals and/or their legalrepresentatives. Those data are discussed in the following paragraphs.

Cancer Incidence and Mortality Rates, Bucks County

The community has expressed concern about elevated incidence of cancer, particularly cancers ofthe breast, lung, and stomach. Cancer mortality data are available from 1970 through 1986. Theonly years for which final county-specific cancer incidence data in Pennsylvania are available are1985 and 1986. Neither cancer incidence in nor mortality of Bucks County residents in 1985were significantly higher in any categories of community concern than for all residents ofPennsylvania and, in some cases, were significantly lower. Rates reported to ATSDR by thePennsylvania Cancer Control Program are in Table 7.

Although evaluating county cancer levels may constitute a first look at the community's health,because the exposed population consists of only a fraction of the county, county rates are aninaccurate proxy for community rates. In addition, it is possible that cancers that may result fromexposure to site-related contaminants might not be detectable as of 1985 because of the latencyof cancer development.

Review of Residence Information from Cancer Incidence Data for Falls Township in BucksCounty, Pennsylvania

The Cancer Control Program at the Bureau of Epidemiology and Disease Prevention,Pennsylvania Department of Health, has investigated a possible cancer cluster in Falls Townshipas identified by members of two citizen groups, Bucks People United to Restore the Environment(B-PURE) and the Delaware Valley Toxics Coalition (DVTC), with the assistance of thePennsylvania Department of Health. The groups analyzed available cancer incidence data for1985 and 1986. An incidence rate measures the number of people who develop cancer ascompared to the number of people in the community. The Cancer Control Program staffmembers reviewed the data, paying special attention to possible inaccuracies in residenceinformation. They found no significant increase in cancer incidence rates in Falls Township. The review concluded that the apparent increase in cancer rates in Falls Township originallyfound by the citizen groups may be attributed to significant misassignments of residence, and thatthe overall risk of developing cancer in Falls Township is not significantly different from theCounty (39).

Medical Records

ATSDR received medical records from individuals and/or their legal representatives. ATSDRreviewed medical records or medical record summaries of five children who live, or have lived,in the study area. Physical exams indicated enlarged and tender livers, rashes, and, in one case,failure to thrive; bloodwork indicated elevated liver enzyme levels; and complaints includedabdominal pain. ATSDR also reviewed medical records or medical record summaries of 15adults who live, or have lived, in the Falls Township study area. General complaints includedstomach problems, diarrhea, poor liver function, rashes, headaches, and joint stiffness. Twopatients suffered from heart disease, two from hypertension, and one had a confirmed diagnosisof breast cancer. As was discussed in the Community Health Concerns section, residentsreported concern about several additional types of cancer.

Individuals' adverse health conditions are of concern, and many of the symptoms noted in themedical records and summaries or brought to ATSDR's attention by individuals are knowneffects of exposure to chemicals contaminating the groundwater at the Falls Township study area. It cannot be established that those noncancer health effects could have resulted from estimatedexposures associated with the study area because current findings in the literature indicate thatthe levels are too low to cause health effects. In addition, because of low contaminant levels andthe long latency period of cancer, it cannot be established that the reported cancers are a result ofexposures to site-related chemicals.

Further activities have been recommended to investigate adverse health effects in the community. Refer to the Public Health Actions section for more information.

C. COMMUNITY HEALTH CONCERNS EVALUATION

Some community health concerns were evaluated in the Health Outcome Data Evaluationsection. Remaining concerns are about birth defects and miscarriages.

The causes of individual birth defects are often difficult to identify. ATSDR staff are not awareof any studies indicating that the contaminants of concern identified in this PHA cause birthdefects. In addition, if exposure to contaminants ceased before conception, unless exposurecaused damage to the egg, the defects cannot be attributed to exposure. ATSDR medical staff arenot aware of any studies which associate exposure to the contaminants of concern with eggdamage. This does not mean that the birth defects are certainly unrelated to exposure; it meansonly that ATSDR cannot determine whether they are associated.

The birth defects described could all possibly have genetic components. Genetic testing of thesisters by their physicians could confirm or rule out that component. In addition, exposure of themother to other insulting chemicals, such as alcohol or cigarette smoke, can affect thedevelopment of the fetus. Likewise, exposure of the father to chemicals affecting sperm canaffect fetal development. Major birth defects are not uncommon; they occur in 6%-7% of livebirths (40). Similarly, miscarriages are common in the population--approximately 15% in thepopulation of otherwise healthy mothers (40, 41). There are a variety of reasons for miscarriages,including aspects of the mother's health status which are unrelated to exposure (e.g.endometriosis). In conclusion: ATSDR cannot determine whether the birth defects andmiscarriages are related to exposure because other common causes of birth defects andmiscarriages have not been ruled out.


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