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PUBLIC HEALTH ASSESSMENT

HELENA CHEMICAL COMPANY LANDFILL
FAIRFAX, ALLENDALE COUNTY, SOUTH CAROLINA


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

Data presented in this section are from the final Remedial Investigation Report and FeasibilityStudy (RI/FS) completed in December 1992. These documents represent the latest available datafor the HCC site. Data were generated in three phases (Phase II-A, II-B, and III) of fieldinvestigations and monitoring from June 1990 through December 1991.

The tables in this section list the contaminants of concern. We evaluate these contaminants in thesubsequent sections of the public health assessments and determine whether exposure to them haspublic health significance. SCDHEC and ATSDR select and discuss these contaminants basedupon the following factors:

1. Concentrations of contaminants on and off the site.

2. Field data quality, laboratory data quality, and sample design.

3. Comparison of on-site and off-site concentrations with public health assessment comparison values for (1) non-carcinogenic endpoints and (2) carcinogenic endpoints.

4. Community health concerns.

In the data tables that follow under the On-site Contamination and Off-site Contaminationsubsections, the listing of a contaminant does not mean that it will cause adverse health effectsfrom exposures. Instead, the list indicates which contaminants will be evaluated further in the public health assessment.

    The data tables and narrative include the following abbreviations:
  • CREG
  • = Cancer Risk Evaluation Guide
  • EMEG
  • = Environmental Media Evaluation Guide
  • RMEG
  • = Reference Dose Media Evaluation Guide
  • RfD
  • = Reference Dose
  • ppm
  • = parts per million, milligrams per kilogram in soil (mg/kg)
  • ppb
  • = parts per billion, micrograms per liter in water (g/kg)

    Comparison values for public health assessments are contaminant concentrations in specific mediathat are used to select contaminants for further evaluation. These values include EMEGs,CREGs, and other relevant guidelines. CREGs are estimated contaminant concentrations basedon a one excess cancer in a million persons exposed over a lifetime. CREGs are calculated fromEPA's cancer slope factor. EMEGs are derived from ATSDR Minimal Risk Level (MRL), theestimate of a daily human exposure to a chemical likely to be without an appreciable risk ofnon-carcinogenic adverse effects, generally for a period of year or longer. EPA's RfD is anestimate of the daily exposure to a contaminant that is unlikely to cause adverse health effects. RMEGs are media-specific comparison values derived from RfDs and are used to selectcontaminants of concern at hazardous waste sites.

    Toxic Chemical Release Inventory (TRI)

    TRI is developed by the U.S. Environmental Protection Agency from chemical releaseinformation provided by certain industries. The chemical release information is based oncontaminants found in air, surface water, groundwater, or soil.

    Project staff conducted a search of EPA's Toxic Chemical Release Inventory (TRI) for the yearsof 1987, 1988, 1989, 1990, and 1991. The search included a 1-mile radius around the HCC site. As the site was not active in these years, TRI does not provide a listing for the site. TRI did notinclude any other facilities within a 1-mile radius of the site.

    A. On-site Contamination

    For the purpose of this evaluation, we define "on-site" as the areas within the Helena ChemicalCompany property boundary (Figure 2). Sampling data from the final Remedial Investigation(RI) report indicate that on-site shallow subsurface soil, subsurface soil, and groundwater contain high levels of polychlorinated pesticides, some metals, and volatile organic compounds.

    Shallow On-site Subsurface Soil

    The RI defines surface soil as soil collected from 1 to 3 feet (') in depth; however, this definitiondoes not meet the definition of surface soil by ATSDR standards. ATSDR defines surface soil assoil collected from 0 to 3 inches (") in depth. ATSDR considers this depth of sampling indetermining the realistic extent within which people could become exposed to contaminants in thismedia. Therefore, this public health assessment will present the RI data of soil from 1' to 3'intervals as shallow subsurface soil samples.

    Approximately 111 soil samples were analyzed during the three phases of the RI to characterizethe areal extent of shallow subsurface soil contamination. The varied distribution of shallowsubsurface soil sampling locations are presented in Figure 4. The sample locations wereconcentrated within the previous operations areas that were used in the formulation of liquidpesticides and waste disposal practices. Higher concentrations of pesticides in on-site shallowsubsurface soil were detected in the area north of the former liquid formulation warehouse. TheRI found DDT and its decomposition products, BHC and its isomers, dieldrin, and toxaphene asthe frequently occurring pesticides in this media. Low levels of volatile and semi-volatilecompounds were also detected in on-site shallow subsurface soil samples. Contaminants ofconcern identified for this medium are presented in Table 2.

    Table 2.

    Contaminants of Concern -- Concentrations in On-site Shallow Sub-Surface Soil* (1 to 3 feet in depth)
    ContaminantConcentration
    Range -
    ppm
    Location
    of
    Maximum
    Value
    Comparison Value
    ppmSource
    Alpha-Hexachlorocyclohexane0.002-1.8SS-16-10.1CREG
    Beta-Hexachlorocyclohexane0.005-6.2SS-16-10.4CREG
    Delta-Hexachlorocyclohexane0.004-0.02SS-14-1
    No Value
    Dieldrin0.004-44SS-18-10.04CREG
    4,4'-DDT0.005-220 DSS-16-12CREG
    4,4'-DDE0.0007-15SS-15-12CREG
    Disulfoton0.097-30SS-17-130RMEG
    4,4'-DDD0.006-60DSS-16-13CREG
    Endosulfan Sulfate0.002-22SS-16-11000Chronic EMEG
    Endrin Ketone0.005-1.2 JSS-13-2
    No Value
    Toxaphene0.17-350SS-15-10.6CREG
    LeadU-0.005SS-1-3
    No Value

    * = Data Source: Ensafe Environmental Consultants Remedial Investigation (1992)
    U = Not Detected
    J = Estimated Value
    D = Identified in an analysis at a secondary dilution factor

    The RI presents isocons displaying the relative distribution of total and individual pesticides atintervals of 1, 2, and 3-foot of depths in soil. Isocons for pesticides indicate that the levels ofcontamination reduce with depth of soil. Because these samples do not represent ATSDRdefinition of surface soil, the data presented in the RI may underestimate the levels ofcontamination found within the top 3 inches of soil. This public health assessment recommendsthat soil samples from 0" to 3" in depth be collected to better characterize the extent of on-sitesurface soil contamination and to evaluate potential health effects from exposures to site relatedcontaminants to on-site workers.

    On-site Subsurface Soil

      A. Soil Borings

    As part of the RI, ten soil borings were sampled during the three phases to determine the presenceor absence of soil and groundwater contamination on the site. Soil boring samples were collectedfrom 2 to 19.5 feet depth. Some of these soil boring were later completed as groundwatermonitoring wells and are discussed in section B of this sub-heading.

    Between 1990 and 1991, 18 on-site subsurface soil borings samples were collected from 9different locations. Soil borings samples were collected from the landfill or around the landfillarea, and from the southeast corner of the site (Figure 5). The samples were collected andanalyzed to determine the possible subsurface soil contamination on the HCC site. The RIindicates that the highest concentrations of pesticides were detected in this media in one samplecollected from within the former landfill area. Contaminants identified as being of concern for thismedium are presented in Table 3.

      B. Monitoring Well - Borings

    During the three phases of the RI, some of the soil boring locations were sampled and latercompleted as monitoring wells. Additionally, new monitoring wells were installed for on-sitelocations to assess the extent of site-related contaminant migration in groundwater beneath thesite. These monitoring wells were completed as shallow or deep wells. Subsurface soil sampleswere collected from shallow monitoring well borings (2' to 22' in depth) and deep monitoring wellborings (38' to 98' depth) - Figure 5. Contaminants of concern identified for this medium arepresented in Table 4.

      C. Trench Excavations

    In June 1990, as a part of Phase II-A of the RI, Ensafe and HCC excavated five trenches in thenorth corner of the property to search for buried containers; these trenches were 25-100 feet long,3 feet wide, and 3 feet deep. Phase II-A also included the excavation of two trenches in the areanext to the south warehouse; these trenches were 25-100 feet long, 3 feet wide, and 6 feet deep. In September 1991, as part of Phase III of the RI, EPA and Ensafe, in an attempt to locate theseptic system used by the facility decided to excavate an additional four trenches(HCTR-8,9,10,&11) around the north warehouse (Figure 6). EPA and HCC discovered sixdrums at sample location HCTR-7; all were rusted and partially crushed, one drum containedliquid.

    Ensafe collected eleven on-site trench samples. 4,4'-DDD was the only contaminant of concernidentified in this media at sample location HCTR-7 at concentrations ranging from 0.024 ppm to 3 ppm.

    Table 3.

    Contaminants of Concern -- Concentrations in On-site Sub-Surface Soil* Soil Borings (2 to 19.5 feet in depth)
    ContaminantConcentration
    Range - ppm
    Location
    of
    Maximum
    Value
    Comparison Value
    ppmSource
    Alpha-Hexachlorocyclohexane0.014-390 JDHCB-9-30.1CREG
    Beta-Hexachlorocyclohexane0.008-270 JDHCB-9-30.4CREG
    Gamma-Hexachlorocyclohexane0.37D-220 JDHCB-9-3200RMEG
    Delta-Hexachlorocyclohexane0.013-210 JHCB-9-2
    No Value
    Aldrin0.014-800 JDHCB-9-220Chronic EMEG
    Heptachlor 0.05-68 JHCB-9-20.2CREG
    Dieldrin0.048-96 JHCB-9-340Chronic EMEG
    4,4'-DDT0.04-2,800 JDHCB-9-22CREG
    4,4'-DDE0.052-21 JHCB-9-22CREG
    4,4'-DDD0.01-750 JDHCB-9-33CREG
    Endrin KetoneU-9.2 JHCB-9-3
    No Value
    Toxaphene0.32-2,700 JHCB-9-20.6CREG
    NaphthaleneU-3.6HCB-2-8
    No Value
    PhenanthreneU-1.4HCB-2-8
    No Value
    2-Methyl NaphthaleneU-12 DHCB-2-8
    No Value
    Disulfoton0.06-430 DHCB-9-330RMEG
    Lead0.0027-0.024HCB-1-1
    No Value

    * = Data Source: Ensafe Environmental Consultants Remedial Investigation (1992)
    U = Not Detected
    J = Estimated Value
    D = Identified in an analysis at a secondary dilution factor
    JD = Estimated value at a secondary dilution factor

    Table 4.

    Contaminants of Concern -- Concentrations in On-Site Sub-Surface Soil* (Monitoring Well Borings)
    ContaminantConcentration
    Range - ppm
    Location
    of
    Maximum
    Value
    Comparison Value
    ppmSource
    4,4'-DDT0.016-42 CM-12-12CREG
    Aldrin1.4-130 CM-12-10.04CREG
    Endrin KetoneU-4.6 CM-12-1
    No Value
    Alpha-ChlordaneU-9.6 CM-12-10.5CREG
    Gamma-ChlordaneU-14 CM-12-10.5CREG
    HeptachlorU-2.7 CM-12-10.2CREG
    Di-n-OctylphthalateU-0.059 JM-6-9
    No Value
    LeadU-0.011M-14-1
    No Value

    * = Data Source: Ensafe Environmental Consultants Remedial Investigation (1992)
    U = Not Detected
    J = Estimated Value
    D = Identified in an analysis at a secondary dilution factor
    C = Pesticide concentration confirmed by Gas Chromatography/Mass Spectrometry

    On-Site Groundwater

    Ensafe conducted a hydrogeological assessment to characterize the contaminant migration ingroundwater beneath the HCC site. As part of the remedial investigation, twenty two monitoringwells were installed in the upper Eocene Aquifer System of the region. Ensafe and HCC installedmonitoring wells in clusters; each cluster was comprised of one shallow and one deep monitoringwell. The deep wells are identified with an odd number and the shallow wells are identified withan even number. The monitoring well locations are presented in Figure 5. Contaminants ofconcern identified for this medium are presented in Table 5.

    Piezometer readings indicate that the direction of groundwater flow in the shallow and deepaquifers vary seasonally. As part of the RI, piezometer readings were collected in August 1990 toApril 1991. The RI concluded that the shallow groundwater flow in August 1990 was to thesouth and southwest and in April 1991 is was to the south, east, and southeast (Figures 7 & 8);and that the deep groundwater flow in August was to the southwest and in April it was to thesouth and southeast (Figures 9 & 10).

    A number of contaminants identified in the on-site groundwater media were detected inmonitoring well M-4. M-4 is located adjacent to the drainage pipe that originates in thenorthwest of the warehouse. This pipe is suspected to have been used prior to the HCC'soccupancy to discharge effluent onto the ground surface.

    The RI detected pesticides, volatile and semi-volatile compounds, and some metals in on-site groundwater. The RI presented the possibility that chlorinated pesticides may have moved togroundwater through diffusion and mass transport mechanisms. Considering the past liquidpesticide formulation process, the RI suggested that organic solvents when mixed withresidualpesticides may have accelerated the rate of pesticide movement into groundwater. The level ofcontamination detected in the shallow aquifer was higher than that found in the deep aquifersamples.

    On-Site Surface Water and Sediments

    An intermittent stream flows around the west and northeast sides of the landfill and runs into aswampy area. A surface water drainage ditch transects the north end of the site and flows paralleltoward the northwest of the site. This drainage ditch discharges into Dutch Creek, a tributarylocated northwest of the property. Dutch Creek flows into the Coosawatchie River located to thewest of the HCC site. Surface water and sediment sample locations are presented in Figure 11.

    EnSafe and HCC collected and analyzed one on-site surface water sample and one sedimentsample. Contaminants of concern identified in these media are presented in Table 6 and 7respectively.

    Air Monitoring

    Ensafe conducted on-site air monitoring throughout phases II-A and II-B of the remedialinvestigation. During the RI, an air particulate meter was installed on the HCC site. Nocontaminants of concern were identified in this medium.

    Table 5.

    Contaminants of Concern -- Concentrations in On-site Groundwater*
    ContaminantConcentration
    Range-ppb
    Location
    of
    Maximum
    Value
    Comparison Value
    ppbSource
    Alpha-Hexachlorocyclohexane0.2-31M-60.006CREG
    Beta-Hexachlorocyclohexane1.2-31M-4 D*0.02CREG
    Delta-Hexachlorocyclohexane0.02-9.2 DM-4 D*
    No Value
    Aldrin0.08-2.3 DM-40.002CREG
    Dieldrin2.4-5.5M-60.002CREG
    ToxapheneU-80M-40.03CREG
    Endrin Ketone0.17-15DM-4 D*
    No Value
    Butyl PhosphorotrihioateU-49JM-151Chronic RMEG
    Benzene5-37M-141CREG
    4,4'-DDE0.05J-2.0M-40.1CREG
    4,4'-DDD0.074J-2.1M-120.1CREG
    4,4'-DDTU-1.2M-120.1CREG
    Arsenic1.4BJ-30M-200.02CREG
    Chromium3.9B-415M-20200RMEG
    Lead1.3B-44M-2015EPA Action
    Aluminum194-292,000M-19
    No Value
    Beryllium1-5M-200.008CREG
    Cobalt41-100M-20
    No Value
    Manganese1.5-666M-23200RMEG
    Iron11B-115,600M-20
    No value
    Vanadium7.9-394M-20100IntermediateEMEG

    * = Data Source: Ensafe Environmental Consultants Remedial Investigation (1992)
    U = Not Detected       J = Estimated Value       D = Identified in an analysis at a secondary dilution factor       B = Possible contamination       BJ = Possible contamination and estimated value       D* = Duplicate Samples collected on pesticides only

    Table 6.

    Contaminants of Concern -- Concentrations in On-site Surface water*
    ContaminantConcentration
    Range - ppb
    Location
    of
    Maximum
    Value
    Comparison Value
    ppbSource
    Beta-Hexachlorocyclohexane0.57-1.2SW-10.02CREG
    Delta-HexachlorocyclohexaneU-0.28SW-1
    No-Value
    Dieldrin0.41-6.2DSW-12Chronic EMEG
    4,4'-DDD0.045J-0.23SW-10.1CREG
    4,4'-DDTU-1.2SW-10.1CREG
    Endrin Ketone0.35-1.4SW-1
    No Value
    Arsenic15.6J-16.7JSW-110Chronic EMEG

    * = Data Source: Ensafe Environmental Consultants Remedial Investigation (1992)
    U = Not Detected
    J = Estimated Value
    D = Identified in an analysis at a secondary dilution factor
    B = Possible Contamination

    Table 7.

    Contaminants of Concern -- Concentrations in On-site Sediment*
    ContaminantConcentration
    Range - ppm
    Location
    of
    Maximum
    Value
    Comparison Value
    ppmSource
    Beta-HexachlorocyclohexaneU-0.5 CHCSD-20.4CREG
    4,4'-DDD0.018-3.4 CHCSD-23CREG
    Toxaphene0.078-42 CHCSD-20.6CREG
    4,4'-DDT0.005-5.7 CHCSD-22CREG
    Lead0.011-0.0675HCSD-2
    No Value

    * = Data Source: Ensafe Environmental Consultants Remedial Investigation (1992)
    U = Not Detected
    C = Pesticide Concentration confirmed by Gas Chromatography/Mass Spectrometry

    B. Off-site Contamination

    This Public Health Assessment (PHA) identified contaminants of concern for off-site soil,groundwater, and sediment. EPA and Ensafe collected and analyzed off-site samples in thesemedia to determine the extent of off-site migration of site-related contaminants. In general, thelevels of contamination in off-site soil, groundwater, and sediment are considerably less than thosedetected on the site.

    Off-site Shallow Subsurface Soil

    As part of the RI, twelve off-site shallow subsurface soil samples were collected. These locationswere selected east of the site boundary, between the landfill and the south end of the propertyalong the CSX railroad line (Figure 4). Toxaphene was the only contaminant of concernidentified (sample location SS-56) at concentrations that ranged from 0.34 ppm to 8.1 ppm.

    Off-Site Subsurface Soil

    During the three phases of the RI, soil borings and monitoring wells were installed to delineate theextent of soil and groundwater contamination. Ensafe collected and analyzed samples from sixoff-site locations to evaluate the extent of site-related contaminants to have migrated off-site(Figure 5). Aluminum was detected in M-10-1 at concentrations ranging from 1.42 ppm to 6.46ppm; delta-hexachlorocyclohexane was found at M-25-1 at concentrations ranging from notdetected to 0.01 ppm.

    Off-Site Groundwater

    During the RI, 6 monitoring wells were installed to determine the extent of groundwatercontamination in off-site locations. The wells were installed hydraulically upgradient anddowngradient of groundwater flow (Figure 5). The RI detected high levels of site-related contaminants, primarily pesticides and metals in M-10 and M-18 (Table 8).

    The municipal water supply well, located less than 200 feet west of the site, is a major source ofdrinking water for the town of Fairfax. It is 344 feet deep and is screened in the TertiaryLimestone, a major aquifer in the area. Ensafe and HCC conducted two aquifer communicationtests to determine if the aquifer supplying water to Fairfax is separated from the shallow aquiferbeneath the site. The tests were inconclusive because identifiable trends did not occur from theshort duration of pumping. However, the data represented in the RI did not identify site-relatedcontaminants in the municipal water supply well.

    Table 8.

    Contaminants of Concern -- Concentrations in Off-Site Groundwater*
    ContaminantConcentration
    Range-ppb
    Location
    of
    Maximum
    Value
    Comparison Value
    ppbSource
    Alpha-HexachlorocyclohexaneU-0.92M-180.006CREG
    Beta-HexachlorocyclohexaneU-2.6M-100.02CREG
    AldrinU-0.88M-100.002CREG
    Endrin KetoneU-18M-10
    No Value
    ChromiumU-79M-1850RMEG Child
    AluminumU-14,200 JM-18
    No Value
    ToxapheneU-36M-100.03CREG

    * = Data Source: Ensafe Environmental Consultants Remedial Investigation (1992)
    U = Not Detected
    J = Estimated Value

    Off-Site Surface Water and Sediments

    A surface water drainage ditch transects the site at the north end of the property and from tworemote locations to the east and west of the site. Ensafe collected one off-site surface watersample (SW-2) and eight off-site sediment samples (Figure 11). Samples were collected todetermine the possibility that site-related contaminants may have migrated off-site. Carbondisulfide was detected; however, we believe this contaminant is a laboratory artifact. Contaminants of concern are presented in Tables 9 and 10 respectively.

    Table 9.

    Contaminants of Concern -- Concentrations in Off-site Surface Water*
    ContaminantConcentration
    Range-ppb
    Location
    of
    Maximum
    Value
    Comparison Value
    ppbSource
    Carbon DisulfideU-1100ESW-21000RMEG Child
    Manganese110-121SW-250RMEG Child

    * = Data Source: Ensafe Environmental Consultants Remedial Investigations (1992)
    U = Not Detected
    E = Estimated value exceeded the upper calibration range of the GC/MS

    Table 10.

    Contaminants of Concern -- Concentrations in Off-Site Sediment*
    ContaminantConcentration
    Range - ppm
    Location
    of
    Maximum
    Value
    Comparison Value
    ppmSource
    Lead0.018-0.014HCSD-10
    No Value
    Phenanthrene U-0.14HCSD-6
    No Value
    ChryseneU-0.15JHCSD-6
    No Value
    Benzo(b)Fluoranthene0.0059-0.17JHCSD-6
    No Value
    Benzo(a)PyreneU-0.15JHCSD-60.1CREG
    Benzo(g,h,i)PeryleneU-0.15JHCSD-6
    No Value
    Aluminum0.918-10.3HCSD-10
    No Value

    * = Data Source: Ensafe Environmental Consultants Remedial Investigation (1992)
    U = Not Detected
    J = Estimated Value

    C. Quality Assurance and Quality Control (QA/QC)

    The data in this section are from the 1992 RI Report and represent the latest available informationfor this site. Quality Assurance and Quality Control (QA/QC) conclusions drawn for this PublicHealth Assessment are determined by the validity of the analysis and conclusions made and theavailability and reliability of the referenced information.

    SCDHEC assumes that adequate quality assurance and quality control measures were followedwith regard to chain-of-custody, laboratory procedures, and data reporting. Overall, the dataappears to be reliable. All data have undergone a quality assurance review. The followingdescribes some inconsistencies and corrective actions for data validation noted in the RIpertaining to soil and groundwater samples at the HCC site.

    During Phase II-B of the RI, 11 shallow subsurface soil samples were resampled from the SS-12, SS-13, SS-15, and SS-20 locations because their volatile analysis holding times had beenexceeded. The RI also states that groundwater samples collected from monitoring wells # 5, 8,10, 12, 12D, and 14 during Phase II-B of the investigation exceeded holding times for volatilefraction of the samples. A second set of samples from those monitoring wells were analyzed forvolatile fraction only. During Phase III of the RI, the laboratory encountered difficulties inanalyzing pesticide fraction of the samples collected from monitoring wells # 16, 19, 21, and 22 and suspected that these samples may have been cross contaminated; they were resampled toavoid data uncertainty.

    Acetone and methylene chloride were detected as the most common volatile organic compoundsin soil and groundwater. The results of QA/QC samples suggests that these are laboratoryartifacts. Bis(2-ethylhexyl) phthalate and carbon disulfide were also detected in soil andgroundwater samples respectively and were identified in the QA/QC samples as laboratoryartifacts.

    D. Physical and Other Hazards

    Several physical hazards were noted during the 1992 site visit. Project staff noted that theremains of an old house is overgrown with heavy vegetation and is littered with concrete blocksand other debris material. Wood pallets, mounds of unknown material covered by black plastic,and various other debris were noted around the back and north sides of the northern warehouse. A swamp area located in the center of the site was not properly posted. The small pit and framedboxes in this area contained standing water. Staff noted a nitrogen gas cylinder, two plasticcontainers, a metal drum, and discarded wood materials on the site. Entry into the southwarehouse is not restricted; this building is in a deteriorating condition and entry into it may resultin physical harm. The heavy vegetation along the western border of the site and the swampyconditions to the west and north of the landfill also represent physical hazards. Project staff alsonoted the remains of five rusted drums on the landfill. These drums may pose a physical hazard to on-site workers or anyone who may wander onto the site.

    PATHWAYS ANALYSES

    To determine whether nearby residents are exposed to contaminants migrating from the site,ATSDR evaluates the environmental and human components that lead to human exposure. Exposure pathways consist of five elements: a source of contamination, transport through anenvironmental medium, a point of human exposure, a route of exposure, and an exposedpopulation.

    An exposure pathway can be eliminated if at least one of the five elements is missing and willnever be present. We categorize exposure pathways that are not eliminated as either completedor potential. For completed pathways, all five elements exist and exposure to a contaminant hasoccurred, is occurring, or will occur. For potential pathways, at least one of the five elements ismissing, but could become completed. For potential pathways, exposure to a contaminant couldhave occurred, could be occurring, or could occur in the future.

    Table 11 presents the potential exposure pathways for the site. The discussion that followsincorporates only those pathways that are relevant to the site. We also discuss the exposurepathways that have been eliminated.

    A. Completed Exposure Pathways

    Currently, there are no known past or present human exposures occurring at the HCC site. Therefore, no completed exposure pathways were identified in this public health assessment. On-site workers may have been exposed to contaminants in the past; however, no data areavailable from the past to evaluate the length of exposure, the concentrations of contaminationfound, or the health effects associated with exposures.

    B. Potential Exposure Pathways

      Soil Pathway

    ATSDR defines surface soils as 0" to 3" in depth; this is representative of the depth at which mostpeople would normally be exposed. Surface soil samples were not collected as part of Ensafe'sRI; therefore, the potential for human exposures to concentrations of contaminants found inon-site and off-site surface soil samples cannot be evaluated.

    During the 1992 site visit, project staff were informed that the landfill area was excavated theprevious summer and filled with soil from other areas of the site. If the soil was clean, those areasalong with areas covered by vegetation would be less likely to contribute to exposure thanuncovered contaminated soil. However, this anecdotal information does not represent samplingdata from this area that would enable our staff to evaluate the extent of surface soilcontamination, if any, remaining in this area of the site.

    The RI collected shallow subsurface soil samples, soil boring samples, and trench excavationsamples to evaluate the extent of soil contamination in and around the HCC site. The

    Table 11.

    Potential Exposure Pathways
    Exposure Pathway ElementsTime
    SourceEnvironmental
    Medium
    Point of
    Exposure
    Route of
    Exposure
    Exposed
    Population
    HCCSoilOn-Site
    Off-Site
    Ingestion
    Dermal Contact
    Adults
    Workers
    Past
    Present
    Future
    HCCGroundwaterOn-Site
    Off-Site
    Ingestion
    Inhalation
    Dermal Contact
    Children
    Adults
    Workers
    Past
    Present
    Future
    HCCSurface Water
    and Sediment
    On-Site
    Off-Site
    Ingestion
    Dermal Contact
    Children
    Adults
    Workers
    Past
    Present
    Future

    shallow sub-surface soil samples were collected at depths from 1' to 3' in one foot intervals, soilboring sample depths varied from 2' to 19.5' in depth, and the trench excavations samples werecollected at 3' and 6' depths. These sampling depths do not represent a potential for humanexposures to site-related contaminants on or around the site. However, the RI identifiedcontaminants of concern in on-site and off-site shallow subsurface soil and subsurface soil. Therefore, exposures to soil contamination at these depths could occur in the future if the site isexcavated and the on-site workers could be exposed to contaminated soil at concentrations ofconcern through accidental inhalation or ingestion of the soil or through dermal contact with the contaminated media.

    The Record of Decision addresses the issues that concern our health assessors in regards to soil contamination at the HCC site. If the remediation is completed as proposed in the ROD and the soil is remediated to the levels that will not pose adverse human health effects, the soil pathway will be re-evaluated and may be eliminated at this site.

    In the past, exposures to concentrations of contaminants in soil at levels of concern may haveoccurred to on-site workers or to anyone who may have wandered onto the site. However, nodata are available to evaluate the length of exposure or the health effects associated with past exposures to on-site soil.

    Surface soil (0" to 3" in depth) samples need to be collected from on-site and off-site locations tobetter characterize the extent of surface soil contamination and to assess the potential adversehealth effects associated with exposures to the contaminated soil. Additional surface soil samplesshould be collected and analyzed from the areas north and northwest of the site, to furthercharacterize the extent of site-related contaminants migration.

      Groundwater Pathway

    Pesticides and volatile organic compounds (VOCs) present in soil may have leached intogroundwater as a result of different physical, chemical, and biological processes. Once ingroundwater, contaminants are transported in the direction of groundwater flow, but at a lowerrate than groundwater. The RI reported that the shallow and deep aquifer groundwater flowpatterns vary seasonally. The RI states that the shallow groundwater flow pattern in Augustflows to the south and southwest and that in the spring it flows to the south, east, and southeast. Deep aquifer flow patterns are to the southwest in August and to the south and southwest in thespring. However, this study was conducted only in the fall and spring months of one year andmore data is needed to better assess groundwater patterns beneath the site.

    Past, current, and future exposure pathways may result from exposures to contaminated on-siteand off-site groundwater at several points of exposure: residential private drinking wells,undeveloped areas, and the site. On-site workers or local residents could be exposed to siterelated contaminants through inhalation, ingestion, or through dermal contact with thecontaminated media.

    In the past, groundwater at the HCC site was not utilized as a drinking water source and a pastexposure pathway does not exist for the site. Additionally, no past exposure pathways can beidentified for off-site locations. The RI did not include residential well sampling in the area;therefore, this PHA cannot evaluate whether local residents who utilized private wells in the pastor are presently utilizing these wells were exposed in the past or are currently being exposed tosite-related contaminants. The RI data indicates that off-site groundwater has been impacted bysite-related contaminants.

    Based upon the available information, groundwater is not currently used as a potable water supplyat the site; therefore, no exposures are known to be occurring. In the future, this pathway couldbecome completed if groundwater at the site were to be used as a potable water supply or if aprivate well is installed in an off-site area of groundwater contamination. Exposures could occurthrough ingestion, inhalation, or dermal contact with the contaminated groundwater.

      Surface Water/Sediment Pathway

    Surface water drainage on the site flows to the north and northwest toward Dutch Creek. Thecreek is located north of the site and could be affected by storm water runoff or by contaminants migrating from the site.

    As part of the RI, one surface water sample and one sediment sample were collected from theHCC site; one surface water sample and eight sediment samples were collected from off-sitelocations. The RI did not collect surface water or sediment samples from Dutch Creek and thispathway cannot be evaluated without sampling data. The sediment samples collected fromlocations along the water way/drainage ditch identified site-related contaminants of concern as faras 400 feet from the site. As no surface water samples were collected from these locations, thesediment data implies that surface water at these locations may also be impacted. The drainageditch discharges into Dutch Creek and then into the Coosawatchie River.

    Past, current, and future exposure pathways may result from exposures to contaminated on-siteand off-site surface water and sediments. The Record of Decision (ROD) proposed for the HCCsite includes regrading of the site's ground surface to prevent and abate surface water runoff. Asthis process is completed, the potential for soil contaminants to migrate off the site will be greatlyreduced. Off-site surface water samples are needed to determine the extent of contamination inthis media. Exposures to the contaminated media may result at the HCC site and Dutch Creek. Exposures could occur to on-site workers who work around the contaminated on-site mediathrough incidental ingestion, inhalation, or through dermal contact with the contaminated media. Local residents could be exposed to site-related off-site contaminants through ingestion,inhalation, or dermal contact with the contaminated media.

    PUBLIC HEALTH IMPLICATIONS

    A. Toxicological Evaluation

    Introduction

    In this section, we will discuss the health effects in persons exposed to specific contaminants,evaluate state and local health databases, and address specific community health concerns. Toevaluate health effects, ATSDR has developed Minimal Risk Levels (MRL) for contaminantscommonly found at hazardous waste sites. The MRL is an estimate of daily human exposure to acontaminant below which non-cancer, adverse health effects are unlikely to occur. MRLs aredeveloped for each route of exposure, such as ingestion and inhalation, and for the length ofexposure, such as acute (less than 14 days), intermediate (15 to 364 days), and chronic (greaterthan 365 days). ATSDR presents these MRLs in Toxicological Profiles. These chemical-specificprofiles provide information on health effects, environmental transport, human exposure, andregulatory status.

    Aldrin and Dieldrin

    Aldrin and dieldrin are similar chemical compounds that are man-made and exist as a white to tanpowder. Beginning in the 1950s, aldrin and dieldrin were used extensively as insecticides oncrops until the U.S. Department of Agriculture stopped this practice in 1970. The EPA approvedthe use of aldrin and dieldrin for killing termites from 1972 until 1987. These chemicals will bediscussed together because aldrin readily changes to dieldrin once it enters the body or theenvironment (ATSDR, April 1993).

    This public health assessment identified potential exposure pathways for aldrin and dieldrin. Human exposures may occur in the future if on-site groundwater, surface water, or subsurfacesoil and off-site groundwater are inhaled, ingested, or come into contact with the skin.

    The health effects from exposure to aldrin and dieldrin are similar; therefore, we evaluated the toxicological literature based on the combined dose a person would receive from exposure tothese chemicals. We then compared the combined dose to the MRL for dieldrin.

    ATSDR established a chronic MRL of 0.00005 milligrams per kilogram per day (mg/kg/day) fordieldrin. ATSDR established the MRL based on animal studies where dogs ingested 0.05mg/kg/day of dieldrin over a two year period (ATSDR, April 1993). The increased levels of liverenzymes in blood indicated that exposure to dieldrin had a mild affect on the dogs' liver. TheMRL established by ATSDR does not imply that these effects will occur in humans who areexposed to dieldrin, but is designed to be protective of human health. In addition, adultvolunteers who ingested as much as 0.003 mg/kg/day of dieldrin for a period of 18 months did not experience increased levels of liver enzymes in the blood (Hunter and Robinson, 1967).

    The estimated dose of dieldrin from incidental ingestion of on-site contaminated groundwater, andsoil would exceed the chronic MRL. Children who ingest off-site groundwater contaminated byaldrin and dieldrin would be exposed to levels of aldrin and dieldrin greater than the MRL. However, these exposure levels are less than levels known to cause adverse health effects inhumans or animals. More studies are needed to evaluate what health effects, if any, will occur in humans from exposure to low levels of aldrin and dieldrin.

    Dermal exposure to the levels of aldrin or dieldrin at the HCC site are not anticipated to cause adverse health effects.

    Arsenic

    Arsenic is a naturally-occurring element in the earth's crust. Pure arsenic is a gray metal-like material, but this form is not common in the environment. Most arsenic compounds arewhite or colorless powders that have no smell or special taste. Arsenic is used as a woodpreservative and in several types of insect killers and weed killers (ATSDR, April 1993).

    This PHA identified potential exposure pathways for arsenic. Past and future exposures to on-sitegroundwater and surface water may occur through inhalation, incidental ingestion or dermalcontact with the contaminated media.

    ATSDR has established a chronic oral MRL of 0.0003 mg/kg/day for inorganic arsenic. ThisMRL was derived from a study of a large Taiwanese population that was exposed to 0.0008mg/kg/day of arsenic in their drinking water supply (Tseng et al. 1968).

    The estimated exposure dose from incidental ingestion of on-site groundwater and surface waterslightly exceeds the chronic MRL for inorganic arsenic. Ingestion of inorganic arsenic at a doseof 0.01 mg/kg/day can cause gastrointestinal irritation, including nausea, vomiting, diarrhea, andabdominal pain (ATSDR, April 1993). The levels of arsenic present in on-site groundwater andsurface water are sufficient to cause a pattern of the skin changes that include corns on the palmsand soles, and areas of hyperpigmentation interspersed with small areas of hypopigmentation onthe face, neck, and back. However, there is no indication that humans have been exposed toarsenic in on-site groundwater or surface water; therefore, these health effects are not anticipated to occur.

    EPA has classified inorganic arsenic as a known human carcinogen on the basis of sufficient data from human studies. Incidental ingestion of contaminated on-site groundwater will result in a no increased risk of developing cancer.

    Benzene

    Benzene is a colorless liquid with a sweet odor. Benzene is manufactured but also occursnaturally in the environment. Various industries used benzene to make other chemicals, such asstyrene (for styrofoam and other plastics) and cyclohexane (for nylon and synthetic fibers).Benzene is also used for the manufacturing of some types of rubber, lubricants, dyes, detergents,drugs, and pesticides. It is also a natural part of crude oil and gasoline (ATSDR, April 1993)The PHA identified potential exposure pathways for benzene. Past and future human exposuremay occur through inhalation, ingestion, or dermal contact with on-site groundwater.

    ATSDR has not established an oral MRL for benzene and the EPA has not established a referencedose for benzene. Adverse immunological effects in animals occur from both inhalation and oralexposure for acute, intermediate, and chronic durations (ATSDR, April 1993). However, thelevel of potential exposure at the HCC site is less than levels known to cause adverse healtheffects in humans or animals. More studies are needed to evaluate what health effects, if any, will occur in humans from exposure to low levels of benzene.

    Dermal exposure to benzene at the HCC site can cause skin irritation for humans or animals. EPA has classified benzene as a known human carcinogen based on sufficient data from humanepidemiological studies. However, the estimated amount of human exposure to benzene at theHCC site is so low that there is no apparent increased risk of developing cancer from incidental ingestion of on-site groundwater.

    Chromium

    Chromium is a naturally occurring element, found in the environment in three different formsincluding: chromium 0, chromium III (trivalent chromium), and Chromium VI (hexavalentchromium). Chromium III is an essential nutrient required by the human body to promote theaction of insulin in body tissues. Chromium is used to make steel and other alloys, bricks formetallurgical furnaces, for chrome plating, in the manufacture of pigments, for tanning leather,wood treatment, and water treatment for industrial applications (ATSDR, April 1993). In ourdiscussion, we will refer to chromium VI as the possible site-related contaminant because it isconsidered to be the most toxic form of the compound. This PHA identified potential exposure pathways for chromium VI. Past and future exposure mayoccur through inhalation, incidental ingestion, or dermal contact with on-site and off-sitegroundwater.

    The EPA has established a chronic oral reference dose (RfD) of 0.005 mg/kg/day for chromiumVI. The RfD is based on animal studies where rats were exposed to 2.4 mg/kg/day of chromiumVI in their drinking water for 1 year.

    The estimated exposure dose from incidental ingestion of on-site groundwater would exceed thechronic oral reference dose (RfD) of chromium VI. A few studies were located regarding theadverse health effects of acute, intermediate or chronic oral exposure of chromium VI. However,these limited studies indicate that the adverse health effects following chromium VI exposureswould occur at levels higher than those detected in groundwater at the HCC site. Availablestudies do not suggest that adverse health effects from dermal exposure to low levels ofchromium at the site are expected.

    EPA has classified chromium VI as a known human carcinogen on the basis of sufficient datafrom human studies. However, this Public Health Assessment could not evaluate the possiblecancer risk for chromium VI because EPA has not defined an estimate of carcinogenic potency ofchromium VI.

    4,4'DDT, 4,4'DDD, 4,4'DDE

    DDT was one of the most commonly used chemicals for controlling insects on agricultural cropsand controlling insects that carry diseases such as malaria and typhus. It is a colorless orwhite/off-white powder, odorless or has a slight aromatic odor. DDD and DDE were also used aspesticides. The manufacture and use of DDT, DDD, and DDE have been banned in the USA(ATSDR, October 1992).

    The RI PHA identified a potential exposure pathway through inhalation, ingestion, or dermalcontact with on-site sediments, surface water, groundwater, and subsurface soil. No off-sitemedia have been impacted.

    ATSDR has established a chronic oral MRL of 0.0005 mg/kg/day for DDT, DDD, and DDE. Since these substances are chemically similar, we have evaluated the combined doses of all threeof these substances in environmental media at the HCC site. However, human exposure tocombined doses of DDT, DDD, and DDE at the HCC site do not exceed the chronic MRL. Adverse health effects from site-related exposure to these contaminants are not expected.

    Sufficient studies are not available to indicate whether adverse health effects in humans or animals may occur through dermal exposure to the levels of DDT, DDD, DDE at the HCC site.

    The EPA has classified DDT, DDD, and DDE as a probable human carcinogens based on datafrom animal studies. However, there is no apparent risk of developing cancer from exposure tothese contaminants at the HCC site.

    Hexachlorocyclohexane (HCH) - Alpha, Beta, and Delta

    Hexachlorocyclohexane is a man-made chemical that exists in eight chemical forms called isomers. Alpha, beta, and delta HCH are three isomers of hexachlorocyclohexane and are present as whitepowder with a musty odor. Lindane, another form of hexachlorocyclohexane similar tobeta-HCH, was manufactured in the United States until 1977 as a pesticide for use on fruit,vegetables, and forest crops. Lindane was also used at one time as a medical treatment forscabies, a contagious skin disease caused my mites (ATSDR, October 1992).

    This public health assessment identified potential exposure pathways for HCH. Exposures mayoccur through inhalation, ingestion, or dermal contact with on-site subsurface soil, groundwater, surface water, and sediments and with off-site groundwater.

    ATSDR has established an intermediate MRL of 0.0005 mg/kg/day for beta-HCH. The MRL isbased on the results from animal studies. The studies concluded that rats exposed to 0.5mg/kg/day of beta-HCH developed liver cancer (ATSDR, October 1992). The MRL establishedby ATSDR does not imply that these effects will occur in humans who are exposed at this level to beta-HCH, but is designed to be protective of human health.

    The estimated dose of HCH from incidental ingestion of on-site contaminated groundwater wouldexceed the intermediate MRL; however, this dose is significantly less than levels known to causeadverse health effects in humans or animals. More studies are needed to evaluate what healtheffects, if any, will occur in humans from exposure to low levels of beta-HCH. Ingestion ofon-site surface water and sediment, and off-site groundwater would not exceed the intermediateMRL.

    Dermal exposure to low levels of beta-HCH at the HCC site are not anticipated to cause adverse health effects in humans or animals.

    Butyl Phosphorotrihioate

    Butyl Phosphorotrihioate is an organic phosphorus pesticide commonly known as DEF. It is acolorless to pale yellow liquid. It is most frequently used as a defoliant of cotton

    This PHA identified potential exposure pathways for butyl phosphorotrihioate. DEF was detectedin on-site groundwater and exposures could occur through ingestion, inhalation, or throughdermal contact with this contaminant. However, groundwater is not currently used as a potablewater supply on the HCC site and exposures are considered unlikely.

    EPA has established a chronic oral reference dose (RfD) of 0.00003 mg/kg/day for butylphosphorotrihioate. The estimated exposure dose through groundwater at the HCC site wouldexceed the reference dose (RfD) for butyl phosphorotrihioate. One study indicates that breedinghens receiving 20 to 80 mg/kg/day of merphos oxide, another form of butyl phosphorotrihioateexperienced weight loss and delayed neurotoxic effects. However, adverse health effects fromexposure to low levels of butyl phosphorotrihioate of on-site groundwater are unlikely.

    Iron

    Iron is an essential metal in the human diet. The Recommended Daily Allowance (RDA) for ironestablished by the Committee on Dietary Allowances of the Food and Nutrition Board is 10 to 15mg/kg/day. However, excess of iron in the diet may result in adverse health effects. Ingestion oflarge amount of iron may cause vomiting, liver damage, and renal failure. Also, excess iron in thediet over time may lead to the accumulation of iron in the liver, disturbance of liver function, andeven cardiovascular effects (Klassen 1986). Some individuals may be genetically sensitive to iron(e.g., Wilson's disease).

    Past and future human exposures to iron may occur through inhalation, ingestion, or dermalcontact with on-site groundwater. The estimated exposure dose to the concentrations found inon-site groundwater through ingestion exceeds the Recommended Daily Allowance (RDA). However, adverse health effects from exposure to iron on the HCC site are not anticipated.

    Lead

    Lead is a naturally occurring element that can be found in most environmental media. It has a wide range of uses including storage batteries (automobile batteries), solders, pipes, various chemicals, and gasoline additives (ATSDR, April 1993).

    This PHA identified potential exposure pathways for lead. Past and future human exposures mayoccur through inhalation, ingestion, or dermal contact with on-site subsurface soil, groundwater,and sediments, and off-site sediments.

    Although lead may cause both acute and chronic effects, major concern has focused on theneurotoxicity of lead in children that may manifest itself as learning disorders. Lead toxicity inadults may contribute to hypertension, particularly in middle-aged males (ATSDR, April 1993).

    ATSDR has not established an MRL for lead. The EPA has not defined a reference dose (RfD)for lead. Although exposure to lead salts has been associated with an increased rate of cancer inlaboratory animals; however, EPA has not defined an estimate of carcinogenic potency of lead. The cancer risk from exposure to lead from this site is unknown.

    Manganese

    Manganese is a naturally occurring substances found in many types of rock. Manganese does notoccur in the environment as the pure metal. Manganese is an essential element, required fornormal growth and maintenance of health. It is mixed with iron to make various type of steel. Some manganese compounds are used in the production of pesticides, fertilizers, and in dietarysupplements (ATSDR, July 1992).

    This PHA identified potential exposure pathways for manganese. Past and future humanexposures may occur through inhalation, ingestion, or dermal contact with on-site groundwaterand off-site surface water. Incidental human ingestion of on-site groundwater contaminated with manganese would exceed the chronic oral reference dose (RfD) for manganese.

    ATSDR has defined a chronic MRL of 0.005 mg/kg/day for manganese. However, human andanimal studies suggests that adverse health effects are unlikely from exposure to the levels ofmanganese detected at the HCC site.

    Polycyclic Aromatic Hydrocarbons (PAHs)

    Polycyclic Aromatic Hydrocarbons (PAHs) are a group of chemicals that are formed during theincomplete burning of coal, oil and gas, garbage, or other organic substances. Completecombustion of PAHs results in carbon dioxide and water. PAHs are man-made or occurnaturally. They are found throughout the environment and are used in medicines and to makedyes, plastics, and pesticides (ATSDR, October 1993). Benzo(b)fluoranthene, benzo(a)pyrene,benzo(g,h,i)perylene, and chrysene are PAHs detected at the HCC site.

    This Public Health Assessment identified a potential exposure pathway for PAHs. Past and futureexposures may occur through inhalation, ingestion, or dermal contact with contaminated off-sitesediments.

    ATSDR has not established an MRL for PAHs. The MRL is designed to identify the minimumrisk of non-cancerous health effects when exposed to a chemical. According to the toxicologicalprofile, the only significant health effects demonstrated in humans following low-level exposure toPAHs is cancer. Although animal studies have indicated that non-cancerous health effects mayoccur; however, these have not been adequately documented.

    Studies indicate that animals ingesting PAHs have developed tumors. Available animal studiesalso indicated that mice have developed tumors following dermal exposure to PAHs. Animalstudies suggested that mice fed with high doses of benzo(a)pyrene during pregnancy had difficultyin reproducing (ATSDR, October 1993). However, the levels of PAHs resulting in these healtheffects are not known. More studies are needed to evaluate what health effects, if any, will occur in humans from exposure to low levels of PAHs.

    The EPA has classified PAHs as probable human carcinogens. Probable human carcinogens arechemicals for which there is sufficient evidence of carcinogenicity in animals, but inadequateevidence or no data from human epidemiologic studies.

    Toxaphene

    Toxaphene is an insecticide. It was used primarily in the Southern United States to control insectpests on cotton and other crops. The EPA banned most uses of toxaphene since 1982 except useon livestock, disinfecting buildings, and some limited uses. It is a yellow-to-amber,waxy solid that smells like turpentine (ATSDR, December 1990).

    This public health assessment identified potential exposure pathways for toxaphene. Past andfuture exposures may occur through inhalation, ingestion, or dermal contact with on-sitesediments and groundwater and off-site groundwater and subsurface soil.

    ATSDR has established an intermediate MRL of 0.00005 mg/kg/day for toxaphene. ATSDRderived the chronic intermediate MRL from mild behavioral effects noted in rats exposed to 0.05mg/kg/day of toxaphene (ATSDR, December 1990). The MRL established by ATSDR does notimply that these effects will occur to humans who are exposed to dieldrin, but is designed to beprotective of human health. Ingestion of on-site surface soil or groundwater by on-site workerswould result in exposure to toxaphene at levels slightly above the MRL. However, the level ofexposure the workers would receive is less than levels known to cause adverse health effects inhumans or animals. More studies are needed to evaluate what health effects, if any, will occur in humans from exposure to low levels of toxaphene.

    Dermal exposure to toxaphene at the HCC site are not anticipated to result in adverse healtheffects in humans and animals.

    The EPA has classified toxaphene as a probable human carcinogen based on data from animalstudies. The surface soil and groundwater concentrations at HCC site are so low, that there is no apparent risk of developing cancer.

    Vanadium

    Vanadium is a naturally occurring element in the earth's crust. It is a white to gray metal, oftenfound as crystals. In the environment, it is usually combined with other elements such as oxygen,sodium, sulfur, or chloride. The forms of vanadium most likely to be found at waste sites are notwell known. One man-made form, vanadium oxide, is most often used by industry to make steel(ATSDR, July 1992).

    The PHA identified potential exposure pathways for vanadium. Past and future exposures mayoccur through inhalation, ingestion, or dermal contact with on-site groundwater.

    ATSDR has established an intermediate MRL of 0.003 mg/kg/day for vanadium. This MRL isbased on animal studies where rats were exposed to 0.3 mg/kg/day of vanadium in their drinkingwater for 3 months (ATSDR, July 1992). Incidental ingestion of on-site groundwater could resultin human exposure to vanadium above the intermediate MRL. However, the levels of exposurethat humans could receive is considerably less than levels known to cause adverse health effects in humans or animals.

    No studies are available regarding adverse health effects in humans or animals from dermalexposure to vanadium. However, adverse health effects through dermal exposure to vanadium atthe HCC site are unlikely to occur.

    Subsurface Soil Contaminants (greater than 1 foot in depth)

    Contaminants identified in subsurface soil (greater than one foot in depth) are not considered tobe a likely route of human exposure. Human exposure to contaminants in soil is most likely tooccur at depths ranging from zero to three inches below the land surface. The contaminantsidentified in subsurface soil have been grouped together for us to discuss possible health effects associated with human exposure to them.

    The only potential exposure pathway identified for chlordane, di-n-octyl phthalate, disulfoton,endosulfan sulfate, heptachlor, gamma-hexachlorocyclohexane, 2-methylnaphthalene, andnaphthalene is through human ingestion or dermal contact with on-site subsurface soil. Exposuresto these contaminants is not known to have occurred and future human exposure to thesecontaminants is unlikely; however, these conditions may change if the site is excavated. SCDHECwill continue to review the sampling data for the HCC site and will revise these evaluations ifnecessary.

    Chlordane is a man-made chemical used as a pesticide and for termite control. Alpha-chlordaneand gamma-chlordane are two major compounds of chlordane. ATSDR has not established anoral MRL for chlordane; however, EPA has established a chronic oral reference dose (RfD) of0.00006 mg/kg/day for chlordane. The levels of chlordane found at the HCC site do not exceedthe RfD. Therefore, adverse health effects are not anticipated from ingestion or dermal exposure to chlordane.

    Di-n-octyl phthalate (DOP) is used in manufacturing plastic products. ATSDR has notestablished an MRL for this compound and EPA has not established a reference dose (RfD) forDOP. Nausea is a common symptom after ingestion of DOP. Effects from dermal exposure withthis compound may cause mild irritation to the skin and eyes. However, the concentrations ofDOP found at the HCC site are not expected to cause adverse health effects from exposures.

    Disulfoton is a manufactured pesticide used to protect vegetable crops. ATSDR has establishedan intermediate oral MRL of 0.00005 mg/kg/day for disulfoton. Animal studies suggest thatneurological effects may result after oral exposures to this chemical. Disulfoton was detected inon-site subsurface soils and exposures to these soils are not anticipated; therefore, no adversehealth effects are anticipated at this time.

    Endosulfan sulfate is a metabolite of endosulfan and exhibits similar toxicological effects. Endosulfan is a man-made insecticide used on food and non-food crops. It is also used as a woodpreservative. ATSDR has established a chronic MRL of 0.002 mg/kg/day for endosulfan. Theestimated exposure levels calculated for endosulfan at the HCC site do not exceed the MRLvalue; therefore, no adverse health effects are anticipated.

    Heptachlor is a synthetic chemical that was used for killing insects in homes, buildings, and onfood crops until 1988. Heptachlor is both a breakdown product and a component of the pesticidechlordane. ATSDR has not established an oral MRL for this chemical. EPA has established achronic oral reference dose (RfD) of 0.0005 mg/kg/day for heptachlor. The concentrations of thischemical found at the HCC site do not indicate adverse health effects from exposures to thischemical. However, available data is limited and more studies are needed to evaluate what healtheffects, if any, will occur in humans from oral or dermal exposure to low levels of heptachlor.

    Hexachlorocyclohexane (HCH) is a man-made chemical that exists in eight chemical forms calledisomers. Gamma-HCH is one of the isomers of hexachlorocyclohexane and was used as aninsecticide on fruit, vegetables, and forest crops. ATSDR has established an acute MRL of 0.003mg/kg/day for gamma-HCH. The estimated levels of exposure to this compound at the HCC sitedo not exceed the MRL value.

    Naphthalene is a white solid known as mothballs, mothflakes, white tar, and tar camphor. It has astrong, but not unpleasant smell. 2-Methylnaphthalene is a naphthalene-related compound used tomake chemicals such as dyes and resins. ATSDR has not established an MRL and EPA has notestablished a reference dose (RfD) for naphthalene. However, naphthalene was only detected inon-site subsurface soil and adverse health effects from oral or dermal exposures are notanticipated.

    Contaminants Not considered of Public Health Concern

    We have determined that several of the contaminants detected at the HCC site are not of publichealth concern at this time. These include aluminum, beryllium, carbon disulfide, cobalt, endrinketone, and phenanthrene. SCDHEC will continue to review sampling data for the HCC site andwill revise this information as needed.

    B. Health Outcome Data Evaluation

    As no health outcome data exists for the Helena Chemical Company site, there is no furtherdiscussion at this time.

    C. Community Health Concerns Evaluation

    The local residents have not expressed community health concerns regarding the site. Wecontacted the Health District offices for information regarding documented health concerns; these offices did not have health data for this area.

    As part of EPA's community relations plan, local residents were interviewed to gather communityhealth concerns. The EPA held a public meeting on May 27, 1993; the primary concerns of theresidents was the possibility that the municipal water well was contaminated. During the RI, themunicipal water supply well was monitored periodically. Monitoring results indicated that themunicipal water supply well was not impacted by site-related contaminants.



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