PUBLIC HEALTH ASSESSMENT ADDENDUM
FORT LAWN, CHESTER COUNTY, SOUTH CAROLINA
This section is based on the data generated in the Phase I andPhase II Remedial Investigation (RI). These investigationsrepresent the most recent and complete set of data. Samplingresults relevant to public health implications are also presentedhere. A complete analysis of historical data may be found in theAugust 1988 Health Assessment.
The tables in the section list the contaminants of concern. Weevaluate these contaminants in the subsequent sections of thisPublic Health Assessment and determine whether exposure to themhas public health significance. This Public Health Assessmentselects and discusses these contaminants based upon the followingfactors:
- Concentrations of contaminants on and off the site.
- Field data quality, laboratory data quality, and sample design.
- Comparison of on-site and off-site concentrations with background concentrations, if available.
- Comparison of on-site and off-site concentrations with comparison values for (1) noncarcinogenic endpoints and (2) carcinogenic endpoints.
- Community health concerns.
In the data tables that follow under the On-site Contaminationsubsection and the Off-site Contamination subsection, listing acontaminant does not mean that it will cause adverse healtheffects from exposures. Instead, the list indicates whichcontaminants will be evaluated further in this Public HealthAssessment. When selected as a contaminant of concern in onemedium, that contaminant will be reported in all media.
The data tables include the following acronyms:
|= Cancer Risk Evaluation Guide|
= Environmental Media Evaluation Guide
= EPA Maximum Contaminant Level Goal
= EPA Maximum Contaminant Level
= EPA Proposed MCLG
= EPA Proposed MCL
= EPA Reference Dose
Comparison values are contaminant concentrations in specificmedia that are used to screen and select contaminants for furtherevaluation. These values include EMEGs, CREGs, and other relevant guidelines. CREGs are estimated contaminantconcentrations based on a one excess cancer in a million personsexposed over a lifetime. CREGs are calculated from EPA's cancerslope factors. EPA's MCLG is a drinking water health goal. EPAbelieves that the MCLG represents a level that no known oranticipated adverse effects on the health of persons should occurwhich allows an adequate margin of safety. PMCLGs are MCLGs thatare being proposed. MCLs represent contaminant concentrationsthat EPA deems protective of public health (considering theavailability and economics of water treatment technology) over alifetime (70 years) at an exposure rate of 2 liters of water perday. While MCLs are regulatory concentrations, PMCLGs and MCLGsare not. EPA's RfD is an estimate of the daily exposure to acontaminant that is unlikely to cause adverse health effects.
Toxic Chemical Release Inventory (TRI)
The Carolawn Company ceased operation before the initiation ofthe EPA Toxic Chemical Release Inventory (TRI). Therefore, noTRI records are available for this site. Additionally, 1988 TRIrecords do not list any other facilities within a 1-mile radius between latitudes 34º 40' 10" and 34º 42' 10" north andlongitudes 80º 55' 24" and 80º 57' 36" west.
Groundwater - Monitoring Wells
Figure 3 shows the location of the monitoring wells andresidential wells. The Phase I RI collected groundwater samplesfrom four monitoring wells and four off-site residential wells inJuly 1986, and from the four monitoring wells and two residentialwells in December 1986. The residential wells will be discussedin the off-site contamination section.
Phase II sampling analyzed all groundwater monitoring wells and aresidential well for volatile organic compounds (VOCs). Thefirst round of samples were taken in late August and earlySeptember, 1988. The second round were taken in October 1988. The laboratory analyzed all samples for VOCs. The samples fromMW-5 and MW-6 were also analyzed for Base/Neutral/Acid (BNA)extractable compounds, PCBs and Pesticides, Metals, and Cyanide.
Table 1 summarizes groundwater data for the contaminants ofconcern detected in the monitoring wells. The RI notes thatgroundwater samples were neither filtered nor decanted in eitherthe field or laboratory. In the 1986 sampling results of Phase Iof the RI, concentrations of several heavy metal concentrationsexceeded EPA Maximum Contaminant Levels (MCL). In the 1988 PhaseII's first round of sampling, only chromium and leadconcentrations exceeded their MCLs; no heavy metals exceededtheir MCLs in the second round of Phase II sampling. The RIattributes this to the amount of purging of the wells which inthe later sampling rounds resulted in sediment-free samples. VOCs were detected in both sampling rounds in excess of theirMCLs.
PCBs and Pesticides were not detected in on-site groundwatersamples.
|ND - 0.022||***||0.01|
|CHROMIUM (VALENCE UNKNOWN)|
|ND - 0.12||***||0.05|
|ND - 0.08||***||0.005|
|ACETONE||ND - 31||ND - 9.2||1.0 RfD|
|ND - 0.009 B||ND - ND||0.005|
|ND - 0.170||ND - 0.016||0.007|
|ND - 0.467||ND - 0.47||0.07|
|ND - 1.2||ND - 0.62||0.003|
|ND - 0.35||0.003|
ND - Not Detected
B - Compound was also detected in the associated laboratoryblank. This detection may represent a laboratoryartifact.
* - DETECTED IN ONLY ONE SAMPLE
** - THE MCL AND MCLG FOR TRANS-1,2-DICHLOROETHYLENE IS 0.1 MG/L.
***- REMEDIAL INVESTIGATION DID NOT INCLUDE FULL METALS DATA FOROFF-SITE MONITORING WELLS.
The Phase I RI collected "surface" and subsurface soil samples(Tables 2 and 3). Composite "surface" soil samples came fromfour zones within the fenced area and on-site zones outside ofthe fenced area to the west and north; the RI does not indicatethe depth of the composite "surface" soil samples. Therefore,this Public Health Assessment will refer to these as shallow soilsamples; this will distinguish these samples from surface soilsamples taken from the upper three inches of soil. The highestconcentrations of several contaminants occurred in compositesample CLSS-101E in an area immediately west of the fence.
Subsurface soil samples came from seven soil borings: four withinthe fenced area, one west of the fenced area, and two north ofthe fenced area.
During the week of December 10, 1990, EPA collected 21 subsurfacesoil samples from nine soil borings from the areas west and northof the fenced area. Samples were taken at the former drum sites. All samples were analyzed for purgeable organics and metals. Five of the samples were also analyzed for extractable organiccompounds.
Organic compounds detected included low levels of acetone, 1,2-dichloroethylene, 2-butanone, toluene, xylene, and miscellaneousextractable compounds. Surface soil samples were not taken. Asthe concentrations of these organic compounds were very low,organic compounds in this sampling round will not be consideredfurther.
Groundwater - Private Wells
This section details groundwater data from the four nearbyresidential wells. Table 4 summarizes the VOCs detected in thesefour residential wells. Table 1 also summarizes data from off-site monitoring wells; these monitoring wells are not being usedas a source of potable water.
Residential well RW-1 was the earliest well to show contaminationand consistently shows the highest concentration of contaminants. This well is considered to be within the contaminant plume. Thewell owner stated in August 1984, that it was no longer in use. However, as both the Phase I and Phase II RI were able to samplethe well, it has obviously not been abandoned. (In this PublicHealth Assessment, abandoning a well means properly removing andsealing a well according to applicable laws.)
|ARSENIC||3.2 - 7.5||2 - 700||EMEG|
|CHROMIUM||ND - 93||10 - 3000||EMEG|
|LEAD||ND - 160||250||ATSDR|
|ACETONE||ND - 0.021 B||200 - 70,000||RfD|
|DICHLOROMETHANE||0.0080 B - 0.051 B||93||CREG|
|1,1-DICHLOROETHYLENE||ND||20 - 7,000||RfD|
|trans-1,2-DICHLOROETHYLENE||ND||40 - 14,000||RfD|
|BIS(2-ETHYLHEXYL)PHTHALATE||ND - 55||50||CREG|
ND - NOT DETECTED
B - COMPOUND WAS ALSO DETECTED IN THE ASSOCIATED LABORATORY BLANK. THIS MAY INDICATE THAT THIS DETECTION WAS A LABORATORY ARTIFACT.
|ARSENIC||7.9 - 29||SB-4||2.8 - 6.8|
|CHROMIUM||3.0 - 28||SB-1||3.0 - 4.4|
|LEAD||1.6 - 7.0|
|DICHLOROMETHANE||ND - 0.01||SB-2||3.0 - 5.9|
|BIS(2-ETHYLHEXYL)PHTHALATE||ND - 0.33||SB-4||3.0 - 6.3|
ND - NOT DETECTED
As these soil depths are not directly accessible to the public,no comparison values are listed. If these soils should bedisturbed, the comparison values would be the same as listed inTable 2.
|ND - 0.016||RW1, 07/86||0.05|
|ND - 0.02||RW1, 07/86||0.005|
|ND - 0.007B||RW1, 12/86||0.005|
|ND - 0.005||RW1, 12/86||0.007|
|ND - 0.84||RW1, 12/86||0.1|
|ND - 0.32||RW4,08-09/88||0.003|
B - Compound was also detected in the associated laboratoryblank. This suggests that the detection of this compoundmay have been a laboratory artifact.
ND - Not Detected
* - For the factors enumerated in the text, the detection oftrichloroethylene probably actually occurred in well RW1.
Residential well RW-2 sits south of the site. The December 1982sampling results for metals and VOCs did not show the presence ofsite-related contaminants. Zinc was detected at a concentrationof 30 mg/L. April 1985 sampling showed low concentrations ofdichloromethane (0.0022 mg/L) and tetrachloroethylene (0.0025mg/L). VOCs were not detected in the July, 1986 samples. Problems with quality control place doubt on analyses of December1986.
According to a telephone interview with a local resident, RW-2 isnot presently used as a drinking water source because they tiedon to municipal water in 1985. However this well has not beenproperly abandoned since samples were able to be collected fromthis well. The RI stated that the pump could not be removed fromthis well.
RW-3 sits southwest of the site. In a telephone interview, aresident stated that this house has not tied on to municipalwater. December, 1982 sampling results for metals and VOCs didnot show the presence of site-related contaminants. April, 1985sampling results showed the presence of benzene (0.0012 mg/L),methylene chloride (0.0039 mg/L), and chloroform (0.0036 mg/L). As these concentrations were below applicable standards andlaboratory data included questionable Quality Assurance andQuality Control, the owners of RW-3 elected not to tie-on tomunicipal water in 1985. The July, 1986 sampling results did notdetect the presence of VOCs in this well.
Because RW-3 continued to be used as a source of household water,the EPA sampled this well on September 28, 1989. The sample wasanalyzed for inorganic elements, purgeable organic compounds,extractable organic compounds, and pesticides. Becausechlordane-related compounds were detected, a second sample fromDecember 15, 1989 was analyzed for pesticides (see Table 5). Other detected compounds were not of public health concern.
RW-4 sits approximately 0.6 miles west of the site. December,1981 and July, 1986 sampling results of this well for metals andVOCs did not show the presence of site-related contaminants. Thehouse associated with this well burned down in approximately1988. The Remedial Investigation indicates thattrichloroethylene was detected at a concentration of 270 mcg/Lduring Phase II sampling. However, the narrative indicates thatonly well RW-1 was sampled; the laboratory reports only denotethat this was a residential well. Because of the lack of aplausible environmental pathway to RW-4, confusion arising fromthe frequent changes in the well numbering scheme between varioushistorical reports, and the presence of this contaminant at asimilar concentration at well RW-1 and nearby monitoring wells,we believe the specimen was probably mislabelled.
Since this well no longer serves a residence, we will notconsider health implications from any contaminants in this well. However, since it has not been properly abandoned, we may need toreconsider this opinion should it be used as a household watersource in the future.
|ALPHA-CHLORDANE||0.014 J||0.013 J|
Data in micrograms per liter (mcg/L, parts per billion, ppb)
ND = Not Detected
J = Estimated Value
N = Presumptive Evidence of the Presence of the Material
No off-site soil data has been located. Sampling of soil outsideof the fenced area but on the original site property is containedin the above section on on-site soil contamination.
The Phase I RI collected surface water samples from theintermittent stream leading away from the site, Fishing Creekupstream of the site, and Fishing Creek downstream of the site. Upstream and downstream samples contained comparableconcentrations of metals. Low levels of dichloromethane, i.e.,0.003 mg/L, appeared in the samples from Fishing Creek downstreamof the site. However, dichloromethane is also a commonlaboratory contaminant; the detection of dichloromethane insurface water may have been spurious.
The Phase II RI collected surface water samples from FishingCreek both upstream and downstream of the site. They wereanalyzed for VOCs listed on the Target Compound List (TCL). Onlylow levels of acetone were detected (0.091 mg/L). Acetone wasnot detected in the laboratory duplicate. Groundwater samplesshow much larger concentrations of acetone. Therefore, thedetection of acetone may represent a true detection.
The Phase I RI collected stream sediments from the drainagecourses leaving the site, from the intermittent stream and fromFishing Creek. The sediments were assayed for EPA PriorityPollutants. Metal concentrations within these samples werewithin natural background levels. Both dichloromethane (0.0061to 0.021 mg/kg) and acetone (0.0059 to 0.045 mg/kg) were alsodetected in the associated laboratory blanks; therefore thedetection of these compounds may represent normal laboratoryerror. However, the detection of acetone may also represent atrue detection for the factors enumerated in the above paragraph. No other compounds were detected.
The Remedial Investigation Report, Appendix F, contains theConestoga-Rovers & Associates Phase II validation reports. TheRound I groundwater monitoring report cited the use of arelatively small number of blanks and a lack of a surrogatecompound for Pesticide and PCB analysis. However, it concludedthat the data were acceptable and complete. The Round IIgroundwater monitoring report concluded that the data hadexcellent precision and accuracy. However, metals were found inthe method blanks at levels high enough to interfere with thereporting of metals in the associated samples.
Also, the data validation reports do not mention the highdetection limits for many volatile organic compounds ingroundwater samples. Because of the high detection limits, othercompounds could have been present but not detected.
The RI Report does not explicitly define the depth from whichshallow soil samples were taken. In determining the probablehealth effects which may occur at this site, people are mostlikely to come into contact with soils from the upper few inchesof soil. Also, contaminants in the superficial soil are mostlikely to be spread via surface runoff or airborne depositionsshould the site surface be disturbed.
The appearance of trichloroethylene in RW-4 needs furtherinvestigation. Specifically, this well lies approximately 0.7miles west of the site. This is away from the direction ofgroundwater flow. This sample may have actually been drawn fromwell RW-1 (see above).
In preparing a public health assessment, ATSDR and SCDHEC rely onthe accuracy, precision, and completeness of the supplied data. It is assumed that standard protocols were followed for chain ofcustody, laboratory procedures, and data reporting.
In general, the site consists of a forest and a fenced fieldcovered with weeds. Access to the fenced area is easily gainedthrough the bent southern gate, spaces between the southeasternfence and the ground, and the spaces both under and between thetwo arms of the northern gate.
Naturally-occurring physical hazards consist of the flora andfauna indigenous to and/or established in the area. Thisincludes fire ants and other stinging insects, snakes, and poisonivy.
Man-made physical hazards include the remaining incinerationequipment, discarded industrial trash, and rectangular ponds ofapproximately 6 inches in depth and 5 feet in length.
To determine whether nearby residents and workers are exposed tocontaminants migrating from the site, ATSDR evaluates theenvironmental and human components that lead to human exposure. This pathway analysis consists of five elements: a source ofcontamination, transport through an environmental medium, a pointof exposure, a route of human exposure, and an exposed individualor population.
ATSDR identifies exposure pathways as completed, potential, oreliminated. For a completed pathway to exist, all five elementsmust exist and exposure to a contaminant must have occurred inthe past, is presently occurring, or will occur in the future. For a potential pathways to exist at least one of the fiveelements is missing, but could exist. Potential pathwaysindicate that exposure to a contaminant could have occurred,could be occurring, or could yet occur. A pathway is eliminatedwhen at least one of the five elements is missing and will neverbe present. The following discussion is limited to pathwaysimportant and relevant to the site.
At the Carolawn Site, environmental sampling data document thatpast waste storage and disposal activities have contaminated soiland groundwater. It is possible that past disposal activitiesmay have also led to atmospheric contamination; however, thisroute of exposure cannot be assessed due to a lack ofenvironmental data. There are currently no completed exposurepathways at this site. Considering the contaminated media, theextent of contamination, and the area demographics, no personsare currently exposed to site-related contaminants.
The major potential routes of future human exposure include theingestion of on-site soil and ingestion of groundwater. There isthe potential for exposures to occur by trespassing on the siteand through the ingestion of chlordane-related compounds fromwell RW-3. Due to the potential for exposure, three scenarioswill be considered in the Public Health Implications section ofthis report. First, the ingestion of water from well RW-3 whichis occurring. Secondly, because of the possibility of futuredevelopment at this site, the ingestion of maximally contaminatedsoil can be anticipated to occur in the future. Third, thelikely ingestion of maximally contaminated groundwater. Thisexists because of the possibilities for contamination of well RW-3, the use of well RW-1 for ingestion, and the installation of anew residential well in the contaminated area. Although currentevidence indicates that well RW-1 is not being used, this thirdscenario conservatively estimates the risk of either using wellRW-1 or any other future wells within the path of contaminantmigration. A fourth scenario could be exposure through the foodchain, however, since exposure is unlikely, this scenario willnot be discussed in the Public Health Implications section.
|EXPOSURE PATHWAY||Ingestion of groundwater at residence RW-3 (chlordane).|
|Time Component||Present and Future|
|1. Source of contamination||Unknown|
|2. Environmental media and transport||Groundwater|
|3. Point of exposure||Well RW-3|
|4. Route of exposure||Household use of Water containing Chlordane (ingestion, inhalation,dermal contact)|
|5. Receptor Population||Residents using RW-3|
|EXPOSURE PATHWAY||Inhalation of vapors from groundwater|
|Time Component||Past, Present, and Future Potential|
|1. Source of contamination||Carolawn|
|2. Environmental media and transport||Groundwater|
|3. Point of exposure||Residence using RW-1|
|4. Route of exposure||Inhalation of organic vaporsarising from contaminated groundwaterunderlying the residence.|
|5. Receptor Population||Residents using RW-1 or living at house|
NOTE: RW-1 sits above the plume of contaminated groundwater. Indoor air monitoring data are not available.
|EXPOSURE PATHWAY||Household use of contaminated groundwater|
|Time Component||Past Completed and Future Potential|
|1. Source of contamination||Carolawn|
|2. Environmental media and transport||Groundwater|
|3. Point of exposure||Residence at RW-1, -2, and -3|
|4. Route of exposure||Household Use of Contaminated Water (ingestion, inhalation, dermal exposure)|
|5. Receptor Population||Residents of RW-1, -2, and -3|
Residences at RW-1 and RW-2 currently use municipal water. Thisroute of exposure is considered potential because of theuncertainties in the area hydrogeology and the lack ofinstitutional controls against the drilling of new wells.
The site is located in an area known to geologists as the easternCharlotte Belt of the Piedmont Physiographic Province of SouthCarolina. The Charlotte Belt consists of high-grade metamorphicrocks which have weathered to saprolite. The saprolite thicknessvaries from a few feet to approximately 150 feet.
Surficial soil observed at the site consists of brown silty sandand clay. The soil thickens toward Fishing Creek with a maximumobserved thickness of 15.7 feet along the creek, southeast of thesite.
Saprolite, formed by the weathering of bedrock, lies beneath thesoil. The saprolite observed at this site is primarily a clayey,silty sand. The thickness of saprolite varies across the sitefrom less than 5 feet to approximately 30 feet.
The depth of bedrock at this site varies from 4.5 feet below theland surface (bls) to 38.5 feet bls. The bedrock consists ofgranodiorite, a granite-like rock, intruded by a number of dikes. Within the bedrock, two major sets of joints and three sets offractures have been identified. Both the joints and fracturesappear to have approximately vertical dips. These featuresindicate that local groundwater flow may be complex within thebedrock.
Groundwater beneath the site occurs in the bedrock along jointsand fractures. Water levels are less than 10 feet below theground surface (bls) near Fishing Creek and deeper than 40 feetbls at the site area. Based on three rounds of water-levelmeasurements, groundwater generally flows in an eastwarddirection beneath the site, with southeast and northeastcomponents of flow toward Fishing Creek. Calculations, based onfield data, estimate that the groundwater flows at a rate of 204feet per year. However, joints and fractures may create localdeviations from this general groundwater flow direction and rate.
Discharge of groundwater into Fishing Creek appears to occur. This is based on the fact that water levels decrease steadilytoward Fishing Creek from the site area.
Groundwater sampling shows the presence of contaminants in on-site monitoring wells, off-site monitoring wells, and off-siteprivate wells. Available data indicates that only one privatewell remains in use as a potable water source although all fourwells remain operational.
Currently available data indicate that the contaminatedgroundwater moves towards the northeast, southeast, and east. This plume moves under private residence RW-1.
Data prior to 1985 indicate the sporadic presence of volatileorganic contaminants in the other private wells RW-2, -3, and -4. This may also indicate laboratory error and/or samplingtechnique.
Residential well RW-1, southeast of the site, has consistentlyshown high levels of contamination with significantconcentrations of volatile organic compounds (VOCs). The ownerof this well stated in August 1984 that he gets his drinkingwater from a well away from the site. Recent studies used RW-1for sampling. The well has not been abandoned. Should this wellbe used in the future, exposure from this source would have to bereassessed.
A December 23, 1986 ATSDR memorandum stated, "The mostsignificant human health threat posed by this site is from thechronic consumption of contaminated groundwater. EPA's 1985extension of city water lines to the three affected wells haseliminated this exposure pathway for the three families livingnear the site." However, this conclusion is not completelycorrect in that one family elected not to use municipal water.
Original data indicated that all three residences and also RW-4had connected to the municipal water supply in 1985. Yet, in1989, one of the residents stated that they still used their wellas a sole source of household water. Subsequent retesting ofthis well only showed the presence of chlordane-related compoundswhich appeared unrelated to the site (see Off-SiteContamination). However, fractured bedrock underlies the site. Fractures may direct contaminated groundwater in directionsdifferent than the superficial groundwater flow. Therefore, thepossibility of future contamination with site-relatedcontaminants in the residential well RW-3 cannot be ruled out.
As stated in the section on QA/QC, the appearance oftrichloroethylene in RW-4 warrants further investigation. Forthe reasons listed in the Off-Site Contamination section, thissample may have actually been drawn from well RW-1. In eitherevent, the house that was served by well RW-4 no longer exists. Local residents state that noted well is not in use. Therefore,a route of exposure does not exist for this well and will not beconsidered further in this report.
Besides ingestion, exposures to VOCs in groundwater can alsooccur through dermal contact (such as in bathing), and throughinhalation (such as in showering and cooking). Becausecontaminated groundwater underlies the residence at RW-1, VOCscould volatilize into the house. Data are not available for theevaluation of these other pathways of exposure.
|Time Component||Past, Present and Future Potential|
|1. Source of contamination||Carolawn|
|2. Environmental media and transport||Soil|
|3. Point of exposure||On-site: subsurface soil data available. Off-site: concentrations unknown.|
|4. Route of exposure||Ingestion and Dermal Contact|
|5. Receptor Population||Trespassers on-site. Persons living in residences adjoining site but nottrespassing.|
Both on-site shallow soil samples and on-site subsurface soilsamples have shown the presence of contamination. The RI Reportdoes not indicate the depth from which the shallow soil sampleswere taken. In general, a person is only likely to come intocontact with the upper 3 inches of undisturbed soil; therefore,only this upper soil layer is relevant to the current publichealth implications at a site.
Off-site soil samples and background soil samples are notavailable. The thick cover of weeds over the site would tend tolimit the spread of soil by wind. Therefore, off-siteconcentrations of soil contaminants are likely to be less thanon-site concentrations. Past agricultural practices may havecaused increased concentrations of lead and arsenic throughoutthe area. Both of these speculations remain unconfirmed.
Because subsurface soil samples are below the ground's surface,people are unlikely to be currently exposed. Contaminants insubsurface soils, however, may be monitored to follow themovement of contaminants through the soil, may serve as sourcesof continued contamination, and may become relevant to publichealth in the future should activities disturb the soils at thissite.
Erosion, which SCDHEC staff observed in the northeast corner ofthis site, could lead to the spread of both surface andsubsurface soils into the neighboring creek system. Sampling ofthe nearby creek system, however, has not indicated that this isor has been occurring in significant amounts.
The incidental ingestion of soil is an important route ofexposure, particularly for children less than six years old (EPAExposure Factor Handbook). Young children ingest significantamounts of soil as a result of their normal hand-to-mouthactivities. Adults and older children ingest less. Because aperson could easily gain access to the site, ingestion of on-siteshallow soil will be considered. However, since toys and othersigns of children were not noted in the residences adjacent tothe site and SCDHEC staff have not noted definitive signs oftrespass on the site, this pathway is not likely to be occurringand will be considered a potential pathway.
|EXPOSURE PATHWAY||Ingestion of contaminated biota|
|Time Component||Future Potential|
|1. Source of contamination||Carolawn|
|2. Environmental media and transport||Discharge of contaminated groundwater to fishing creek with subsequent fish contamination|
|3. Point of exposure||Fishing creek|
|4. Route of exposure||Ingestion of fish|
|5. Receptor Population||Fishermen, families and associates|
NOTE: Current data does not show contamination of Fishing Creek. However, hydrogeologic data that contamination is a possibilityin the future.
|Time Component||Past, Present and Future Potential|
|1. Source of contamination||Carolawn soil, surface water, and groundwater.|
|2. Environmental media and transport||Uptake of contaminants by plants|
|3. Point of exposure||Ingestion of Plants|
|4. Route of exposure||Persons ingesting plants.|
|5. Receptor Population||Not documented at present.|
Citizen complaints specifically mentioned concerns about gardensexposed to smoke and debris in November 1979. Use of groundwaterfor irrigation is possible. Ecologic data for Fishing Creek arenot available. Hunting and fishing activities are unknown. Staff noticed various edible plants and animals during the sitevisit.
In this section we will discuss the health effects which mayimpact on people exposed to site-related contaminants. Toevaluate health effects which may result from an exposure, ATSDRhas developed Minimal Risk Levels (MRLs). MRLs estimate anexposure which is not likely to cause deleterious health effects;exposure to even lower amounts would be even less likely to causeadverse health effects. MRLs are specific to the route ofexposure and the length of exposure. Routes of exposure mayinclude ingestion (eating and drinking), inhalation (breathing),and dermal absorption (absorption through the skin). Theduration of exposure is commonly classified as acute (less than14 days), intermediate (15 to 364 days), and chronic (greaterthan 365 days) exposures.
ATSDR developed MRLs to assess the possible toxicity of compoundsto body organs. MRLs do not include information on the potentialof compounds to cause cancer. In general, we assume that aperson exposed to small amounts of a carcinogenic compound willincur a small increase in the statistical probability ofdeveloping cancer. A person exposed to larger doses of thecompound will incur a larger increase in the statisticalprobability of developing cancer.
This Public Health Assessment expresses the additionalprobability of developing cancer as a result of an exposure to achemical in terms of no increased risk, no apparent increasedrisk, a low increased risk, a moderate increased risk, and a highincreased risk. EPA has developed a mathematical methodology forestimating the extreme maximum probability that a person willdevelop cancer as a result of exposure to a chemical. The EPARisk expresses estimates in the corresponding terms of less thanone-in-a-million risk, one-in-one-hundred-thousand risk, one-in-ten-thousand risk, one-in-one-thousand risk, and one-in-one-thousand risk.
ATSDR also develops Toxicological Profiles on chemicalcontaminants commonly found at hazardous waste sites. Thesedocuments provide information on health effects, environmentaltransport, human exposure, and regulations affecting thesesubstances.
The human exposure pathways section of this Public HealthAssessment lists the routes by which site-related contaminantsmay enter the human body. As stated above, an evaluation ofthese hazards relies on an accurate estimation of the amount ofthese chemicals to which a person may be exposed. This estimatewill use several standardized assumptions.
We will assume that an adult weighs 70 kilograms (154 pounds) anda child weighs 10 kilograms (27 pounds). An adult ingests 2liters of water per day (2 L/day, the same as a 2-liter sodabottle). A child drinks half that amount (1 L/day). During thecourse of the day, adults typically ingest 50 to 100 milligramsof soil per day (mg/day); this occurs by both inhaling small soilparticles carried in the air and by placing soiled hands andother objects in the mouth. Because small children typicallyplace objects in their mouths, it is assumed that they ingest agreater amount of soil, typically 200 mg/day.
Because neither off-site soil sampling data nor on-site surfacesoil data are available, the ingestion of on-site subsurface soilwill be used to represent an extreme "worst-case" scenario.
The following discussions of chemicals rely on the preceding assumptions combined with the information in the ExposurePathways section.
Arsenic is a naturally occurring element in the earth's crust. The main use for arsenic in the United States is as a pesticide. This was very common in South Carolina during the first half ofthis century. The combustion of fossil fuels and the smelting ofmetals also release a significant amount of arsenic to theatmosphere.
Ingestion of arsenic may lead to irritation of thegastrointestinal tract, toxicity of the nervous system, changesin the number of blood cells, and damage to the liver and kidney. Arsenic intake may lead to characteristic skin changes. Arsenicconsumption has been reported to increase the risk of cancer ofthe skin, liver, bladder, kidney, and lung.
At the Carolawn site, sampling detected arsenic in shallow andsub-surface on-site soils. Sampling did not detect arsenic ingroundwater. As no off-site exposures are currently documented,no health effects are expected at the present time.
If future situations should lead to contact with on-site soil,the standard assumptions listed in the Public Health Implicationssection introduction may be used to calculate a maximum doseresulting from the ingestion of subsurface soil. Comparing thisdose to Figure 2.5 of the ATSDR Toxicological Profile forArsenic, this hypothetical dose is less than the ATSDR MinimalRisk Level (MRL). Therefore, no significant health threat isanticipated, other than an increased cancer risk. Additionally,this dose would result, at most, in a low increased risk ofcancer over the course of a lifetime.
Chromium is a naturally occurring element found in threedifferent valence states: chromium 0, chromium III (trivalentchromium), and chromium VI (hexavalent chromium). In nature,most chromium is trivalent. Chromium is used to make steel andother alloys, bricks for metallurgical furnaces, chrome plating,pigments, leather tanning, wood treatment, and water treatment.
Chromium III is an essential nutrient that helps to maintainnormal metabolism of glucose (sugar), cholesterols, and fat inhumans. The National Academy of Sciences Drinking Water andHealth (Volume 3, page 367) states: "Compounds of chromium in thetrivalent state have no established toxicity. When taken bymouth they do not give rise to local or systemic effects and arepoorly absorbed. No specific effects are known to result frominhalation. In contact with the skin they combine with proteinsin the superficial layers, but do not cause ulceration."
Chromium VI is irritating to the skin and nasal passages. In thebody it attacks the liver, kidney, and central nervous system. Inhalation of high levels of hexavalent chromium has beenassociated with an increased risk of lung cancer in humans.
At Carolawn, sampling has not determined if the chromium ispresent in the trivalent or hexavalent state. Because of thedifferences in health effects between chromium III and chromiumVI, no further statement may be made about the probable healtheffects resulting from chromium at this time.
Lead is a naturally occurring element which may be found in mostenvironmental media. Lead has a wide range of uses includingstorage batteries (automobile batteries), solders, pipes, variouschemicals, and gasoline additives.
Although lead may cause both acute and chronic effects, majorconcern has been focused on two chronic effects of lead toxicity. Chronic lead toxicity is associated with irreversible centralnervous system and peripheral nervous system damage in children; this may express itself as difficulty in learning. Lead exposuremay also be associated with anemia. Lead toxicity is alsoassociated with hypertension in adult males, although studiesdisagree as to whether this effect is more pronounced in white orblack males.
ATSDR has not set an MRL for lead. EPA has not set a referencedose (RfD) for lead. Although exposure to lead salts has beenassociated with an increased rate of cancer in laboratoryanimals, EPA has not set an estimate of the carcinogenic potencyof lead.
Private well RW-3 is used as a potable water source. Sampling ofthis well does not show the presence of lead in excess of healthbased standards. Therefore lead toxicity is not reasonablyexpected at the present time from the ingestion of this water.
Concentrations of lead found in groundwater monitoring wellsexceed the EPA action level. Therefore the future use of privatewell RW-1, the future installation of a private well in thecontaminated area, or the migration of contaminants to currentlyused private well RW-3 could be expected to lead to thedevelopment of nervous system toxicity in children, anemia, andpossibly high blood pressure in adults.
Chlordane and Related Compounds
Sampling of private well RW-3 showed the presence of low levelsof chlordane in off-site groundwater. The Phase I RemedialInvestigation (RI) did not show the presence of chlordane inpesticide samples from on-site monitoring wells. Therefore thepresence of chlordane may be unrelated to the Carolawn site.
According to the ATSDR Toxicological Profile for Chlordane,Chlordane is a pesticide. It is a mixture of various relatedchemicals. It is used mostly to protect houses from termites andto protect corn and other crops from insects. (The owners ofwell RW-3 state that their house was last treated for termitesaround 1968. A small field sits across the road from well RW-3. Both of these could be the source of the detected chlordane.)
Although EPA canceled registration of chlordane for all usesabove the ground in 1983, any chlordane that had already beenbought or was still on the store shelves could be used above theground until April 1988. Beginning in the fall of 1987,chlordane could only be used outside of buildings to controltermites.
Laboratory animals ingesting low amounts of chlordane for aprolonged time period have developed changes in the liver,kidneys, and digestive tract. As RW-3 represents both the onlyhome not using municipal water and the only detection ofchlordane, exposure to chlordane appears limited to thishousehold. The total concentration of chlordane relatedcompounds in this water was 0.0019 mg/L. Ingestion of this waterresults in a dose which is less than the ATSDR Minimal Risk Levelfor chlordane (ATSDR Figure 2.2). An adult ingesting this waterwould receive a dose less than the EPA oral Reference Dose (RfD). A child would receive a dose only slightly above the RfD. Therefore, no increased health risk to the body organs would beexpected to occur as a result of ingesting this water.
Oral exposure to high levels of chlordane for a prolonged periodof time was associated with an increased rate of hepatocellularcarcinomas in mice. Studies in rats have not shown an increasedrate of cancer. Mutagenicity tests have generally not showndamage to DNA. Studies of humans working in the manufacture ofchlordane have not shown an increased rate of cancer. Therefore,EPA classifies chlordane as a probable human carcinogen. Basedon animal studies, the ingestion of water containing 0.0019 mg/Lof chlordane for a lifetime could result in a low increased riskof developing cancer (ATSDR Figure 2.2). As it is unlikely thatthe residents have ingested this compound for a lifetime, theactual risk to these two people would be even less.
Acetone is a clear, colorless liquid with a characteristic fruityodor. It is a natural part of the human body's chemistry as wellas a natural substance in other animals, plants, and insects. Industrially, acetone is a solvent used in a wide variety ofapplications.
Acetone's toxicity is similar to the toxicity of ethyl alcohol. High concentrations of vapors may irritate the eyes and nasalpassages. Systemic symptoms of acute exposure to high levels ofacetone simulate ethyl alcohol intoxication. Exposure to lowerlevels for 90 days has produced damage to the liver and kidneysof rats.
ATSDR has not authored a Toxicological Profile for Acetone. EPAhas set an oral Reference Dose (RfD) of 0.1 mg/kg/day, citingdamage to the liver and kidneys of rats as the most sensitiveeffect of acetone toxicity.
At Carolawn, sampling detected acetone in shallow soil andgroundwater. The trace amounts of acetone detected in soil arebelow levels which would indicate a public health concern. Additionally, available evidence indicates that the area ofcontaminated groundwater is not currently used as a potable watersource. Both of these facts indicate no likelihood that healtheffects from acetone are occurring at the present time. However,as acetone is highly volatile and the area of contaminatedgroundwater underlies a residence, the possibility of acetonevapors in this residence should be considered. Air data frominside this home is not available.
Ingestion of contaminated groundwater can be considered as afuture possibility. This is possible in the event that extantprivate well RW-1 should be again used as a private water source,another potable well is placed within the contaminated area, orthe unlikely event that on-site contaminants migrate to thecurrently used well (RW-3). An adult ingesting water containing31 mg/L of acetone would receive a dose approximately ten timesthe EPA RfD. A child ingesting the same water would receive adose thirty times the RfD. Damage to the liver and kidneys couldresult.
1,1-Dichloroethylene (1,1-DCE) is a chemical used to make variousother chemicals such as plastics (e.g., SARAN wrap) and flame-retardant fabrics. It is a clear, colorless liquid with a mild, sweet smell.
For the most part, information on the human toxicology of 1,1-DCEdoes not exist; the probable toxic effects in humans are derivedfrom both the toxicology of similar compounds and from animaldata. Exposure to 1,1-DCE has caused damage to the liver,kidney, heart, lungs, and central nervous system in animals. There are few medical reports to prove that human exposure to DCEaffects health. In one study, animals exposed to 1,1-DCEdeveloped an increased rate of cancer. Although 1,1-DCE has notbeen shown to cause cancer in humans, a cautious approachconsiders that 1,1-DCE may cause an increased risk of cancer inhumans because of this one suggestive study.
At Carolawn, Phase I and Phase II sampling found 1,1-DCE in bothmonitoring wells and private residential wells; the highestlevels appeared in RW-1 and MW-6. Sampling did not detect 1,1-DCE in soils. Currently, available evidence does not indicatethe presence of 1,1-DCE in private well RW-3. As this is theonly residential well in use, the ingestion of 1,1-DCE ingroundwater is not currently causing health effects.
1,1-DCE is highly volatile. As the maximum detectedconcentration of 1,1-DCE occurred in private well RW-1, it isreasonable to assume that volatilization of 1,1-DCE from thecontaminated groundwater may move through the unsaturatedsaprolite and enter this residence. As no air sampling frominside this house is available, this pathway cannot be furtherevaluated at the present time.
The future potable use of well RW-1, the use of another wellwithin the contaminated area, or the unlikely migration of on-site contaminants to well RW-3 could lead to an increased risk ofboth carcinogenic and non-carcinogenic effects.
The maximum concentration of 1,1-DCE detected in groundwater,0.170 mg/L, could lead to doses approximately twice the ATSDRchronic oral MRL in children. Because ATSDR used a safetyfactors of 1,000 in the derivation of this MRL, the maximumexpected dose of 1,1-DCE at the Carolawn site is still below thedoses which have caused adverse health effects in animals. It isnot certain that these doses would cause health effects inhumans. If health effects were to occur, animal studies indicatethat the most likely effects would include damage to the liverand kidneys (ATSDR Toxicological Profile for 1,1-Dichloroethene). The presence of other similar compounds, such astrichloroethylene, however, may tend to interact with thetoxicity of 1,1-DCE and increase the probability of theseeffects.
On the basis of Figure 2-2 of the ATSDR Toxicological Profile, ahypothetical adult ingesting maximally contaminated water over alifetime would incur a moderate increased risk of developingcancer as a result of this exposure. However, carcinogenesis of1,1-DCE has been observed in only one strain of mice afterinhalation of high levels of the compound. The significance ofthis finding to humans remains debatable.
1,2-Dichloroethylene, also called 1,2-DCE, refers to two closelyrelated chemicals: cis-1,2-dichloroethylene and trans-1,2-dichloroethylene. In general, these two chemicals occurtogether. It is used to make other chemicals and it is used as asolvent.
The inhalation of high levels of 1,2-DCE have caused irritationof the eyes, central nervous system depression, and damage to theliver, kidneys, lungs, and heart. Although air sampling remainsunavailable at the Carolawn site, the probable concentrations ofthis compound are unlikely to cause these effects. As withsimilar compounds at this site, volatilization from contaminatedgroundwater with subsequent exposure to the residence RW-1 cannotbe evaluated on the basis of current data.
As previous testing of private well RW-3 did not show thepresence of 1,2-DCE, RW-3 is the only well currently in use nearthe site, and superficial soil analyses did not reveal thepresence of 1,2-DCE, no health effects are expected from theingestion of 1,2-DCE at the current time. However, ifcontaminated groundwater should be used for ingestion, anexposure and the possible development of health effects wouldoccur. The use of RW-1 for a water supply or the installation ofanother well in the contaminated area could lead to the ingestionof contaminated groundwater, the inhalation of contaminants, andthe dermal absorption of contaminants. This would also occur inthe unlikely but possible event that contaminated groundwatermigrated to the currently used well RW-3.
The chronic ingestion of 1,2-DCE by animals has resulted in adecreased number of red blood cells (anemia). The ingestion ofmuch higher levels has caused central nervous system depression. EPA's Integrated Risk Information System Database (IRIS) cites a90-day mouse drinking water study. In this study, the male miceshowed increases in serum alkaline phosphatase; this may indicatedamage to the liver.
The maximum dose of 1,2-DCE is less than the acute andintermediate MRL (ATSDR Toxicological Profile for 1,2-Dichloroethene). However, this dose is greater than EPA'sReference Dose. Therefore, the chronic future consumption andother household uses of contaminated groundwater may lead to anincreased incidence of liver damage and anemia. The presence ofseveral closely related compounds at this site may increase theprobability of toxicity. These effects, however, would not occurunless contaminated groundwater is used for a household supply.
Trichloroethylene, TCE, is a colorless liquid with an odorsimilar to chloroform. it is mainly used as a solvent anddegreasing agent. Common household products containing TCEinclude some typewriter correction fluids, paint removers, glues,and spot removers. TCE may also be altered to form otherchemicals.
Animal studies indicate that the liver and kidney are theprincipal targets of oral TCE toxicity. However, the ingestionof groundwater from this site would not contribute a dose largeenough to damage these organs (ATSDR Toxicological Profile forTrichloroethylene, Figure 2.4).
Also based on animal studies, trichloroethylene may cause anincreased incidence of various forms of cancer. Currently, noindividuals are ingesting groundwater at the site with theexception of private well RW-3. TCE was not detected in thiswell in its last sampling. Therefore, there is no current routeof exposure indicated. However, the ingestion of contaminatedgroundwater may be considered as a future possibility. This ispossible should extant private well RW-1 be used again as a watersource, another potable well be placed within the contaminatedarea, or the unlikely event that on-site contaminants migrate tothe currently used well (RW-3). In these cases, an adultingesting maximally contaminated groundwater would incur a low tomoderate increased risk of developing cancer as a result of thisexposure.
Bis-(2-EthylHexyl)Phthalate, a.k.a. Di-EthylHexyl-Phthalate orDEHP, is a liquid used to make plastic more flexible. Theseplastics are widely used in consumer products such as imitationleather, rainwear, footwear, upholstery, flooring, tablecloths,shower curtains, food packaging materials, and children's toys. DEHP is also used as a hydraulic fluid and as a dielectric fluidin electrical capacitors.
According to ATSDR, there are essentially no studies on thehealth effects of DEHP in humans. In laboratory animals, highdoses of DEHP may produce liver damage, produce damage to themale reproductive system, affect reproduction, and produce birthdefects. DEHP has been shown to cause an increased incidence ofcancer in rats and mice. None of these effects has beendocumented in humans. Based on an increase in the weights oflivers in female guinea pigs, ATSDR has set an oral chronic MRLof 0.019 mg/kg/day.
Currently, recent sampling has not detected DEHP in well RW-3. As this is the only currently plausible exposure pathway, nohealth effects from DEHP are expected at the current time.
Similarly, the incidental ingestion of soils would only expose anindividual to insignificantly small doses of DEHP.
However, under worst case conditions, any future ingestion ofcontaminated groundwater would present a dose which slightlyexceeds the MRL for a child. It is therefore possible that theingestion of DEHP from this site would cause injury to the liver.
Comparing the adult dose to ATSDR's Toxicological Profile forDi(2-EthylHexyl)Phthalate (Figure 2.4), an individual ingestionmaximally contaminated groundwater for a lifetime would receive,at most, a low to moderate increased risk of developing cancer asa result of this exposure.
The State of South Carolina does not currently have animplemented database or registry dealing with health effects inthe vicinity of this site. Therefore, no evaluation may be madeof health outcome data.
In group discussions, area residents listed specific concerns. These will be evaluated in this section.
1. Does the use of private well RW-3 pose a threat to the healthof the people using this well?
As explained in the above sections, thorough testing of well RW-3has shown only low levels of chlordane-related compounds. Theamount of chlordane is below the EPA MCL; this water could belegally used as a public water source. Additionally, availabledata do not indicate when this exposure began. Considering theuncertainty in the length of exposure and the small populationinvolved, it appears highly unlikely that ingesting the currentconcentration of chlordane-related compounds in well RW-3 wouldresult in significant health effects.
2. Could private well RW-3 become contaminated in the future?
Water from wells RW-1 and RW-2 have shown contamination at levelsunsuitable for human consumption. Well RW-3 has not shown suchcontamination. Additionally, data from on-site and off-sitemonitoring wells and regional topography indicate thatgroundwater flows towards the northeast and southeast of thesite. Thus, it appears unlikely that well RW-3 will becomecontaminated.
However, because of the uncertainties inherent in the localgeology, it cannot be absolutely stated that well RW-3 will notbecome contaminated. Additionally, future projections ofchlordane-related compounds in this well cannot be made fromavailable data. Therefore, this recommends the yearly samplingof well RW-3 for VOCs and pesticides.
3. Could fishing and swimming in Fishing Creek lead to healtheffects?
Sampling of water and sediments for the Remedial Investigationindicate that the Carolawn site has not adversely affectedFishing Creek. However, the site groundwater discharges toFishing Creek and tributaries lead from the site to FishingCreek. Future contamination is possible. Therefore, this recommends a regular schedule of sampling of Fishing Creek forVOCs.
4. Will the presence of this site affect the sale of myproperty?
The reviewers are not qualified to discuss this question.