PUBLIC HEALTH ASSESSMENT
GAFFNEY, CHEROKEE COUNTY, SOUTH CAROLINA
Data in this section are from the February, 1991 Final Remedial Investigation Report. This representsthe latest information for this site. However, these data have not been through the standard reviewprocess. Any changes in these data will necessarily lead toward a reassessment of this section andthe Public Health Implications section of this document.
Contaminants identified as being of concern are presented in table form in this section. We evaluatethese contaminants in the subsequent sections of this public health assessment and determine whetherexposure to them has public health significance. SCDHEC and ATSDR select and discuss these contaminants based upon the following factors:
- 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.
- Community health concerns
In the data tables that follow under the On-site and the Off-site Contamination subsections, the listed contaminant does not mean that it will cause adverse health effects from exposures. Instead, the list indicates which contaminants will be evaluated further in the public health assessment.
| ||= Cancer Risk Evaluation Guide|
|= Environmental Media Evaluation Guide|
| ||= Maximum Contaminant Level Goal|
| ||= Maximum Contaminant Level|
| ||= Proposed Maximum Contaminant Level Goal|
| ||= EPA Maximum Contaminant Level|
| ||= Reference Dose|
| ||= Lifetime Health Advisory|
| ||= parts per million|
| ||= parts per billion|
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 based on one excesscancer in a million persons exposed over a lifetime. CREGs are calculated from EPA's cancer slopefactors. EPA's MCLG is a drinking water health goal. EPA believes that the MCLG represents alevel at which "no known or anticipated adverse health effect on human health occurs which allowsan adequate margin of safety." PMCLGs are MCLGs that are being proposed. MCLs representcontaminant concentration that EPA deems protective of public health (considering the availabilityand economics of water treatment technology) over a lifetime (70 years) at an exposure rate of 2liters of water per day. While MCLs are regulatory concentrations, PMCLGs and MCLGs are not. EPA's RfD is an estimate of the daily exposure to a contaminant that is unlikely to cause adversehealth effects.
Toxic Chemical Release Inventory (TRI)
The Toxic Chemical Release Inventory (TRI) is a database managed by the EPA since 1987. Theinventory contains information on the annual estimated releases of over 300 toxic chemicals into theenvironment (air, water and land) by industry. Mandated by federal regulations, Title III of theSuperfund Amendments and Reauthorization Act (SARA) of 1986, facilities with 10 or more full-timeemployees are required to report to the EPA on releases of any of those 300 toxic chemicals duringtheir business activities. Based on these reports, a database has been established and continuouslybeen updated annually. The database records the names and addresses of facilities whichmanufacture, process, or use these toxic chemicals, as well as amounts released to environment ortransferred to waste sites.
We searched TRI data for the area within a 1-mile radius of the Medley site using both geographiccoordinates and area zip codes. The TRI data search did not contain any information on toxicchemical release in the area around the Medley site.
Groundwater - Monitoring Wells
The groundwater investigation conducted during the RI was intended to determine the nature andextent of groundwater contamination resulting from previous site activities and to characterize thenature of groundwater contamination in the underlying aquifers. The RI was also intended to providegeologic and hydrogeologic information about the site. Hydrogeologic data indicate thatgroundwater flow on the site is primarily to the southeast towards Jones Creek. Jones Creek and itstributaries serve as zones for groundwater discharge from the site (10).
Twenty one on-site groundwater monitoring wells were installed during phase one and phase two ofthe site investigations conducted for the preparation of the RI/FS (Figure 2). Three wells (BW1,BW2, and BW3) were constructed in the bedrock aquifer (BW), three wells (SW1, SW3, and SW4)were constructed in the saprolite (or shallow) aquifer, and one water level piezometer well (PZ1) wasconstructed for water level measurement only (PZ) during Phase I of the RI. Fourteen additionalmonitoring wells and one additional piezometer well were installed during Phase II of the RI, Figure 2. (Seven of these wells were installed in the saprolite wells, and seven were constructed in thebedrock aquifer).
Contaminants detected in this media consisted of volatile organic compounds (VOCs) from thesaprolite and bedrock wells. The saprolite (shallow) aquifer generally serves as a porous medium ofgroundwater flow. The groundwater in the bedrock (deep) aquifer at the site is under semi-confinedto confined conditions and is not conducive to groundwater flow. The saprolite wells have anaverage depth of 33 feet, while the bedrock wells have an average depth of 100 feet. The highestconcentrations of VOCs were found directly beneath the source area. No VOCs were detected insamples SW1, BW1-2, BW3-2, BW4-1, and BW4-2. No groundwater plume has been identified toindicate that contaminant migration has reached Jones Creek (10). Table 2 presents the contaminantsidentified as being of concern in this media. There are no private wells on-site.
|Methylene Chloride||38 BJ||SW106-4||110 D||BW2-1||PMCL||5|
|1,1,1-Trichloroethane||3300 E||SW4-1||310 D||BW2-1||MCL||200|
µg/L = micrograms per liter
B = Compound detected in corresponding blank.
D = Sample diluted for this analysis.
E = Estimated value. Analyte concentration exceeded the calibration range. These values are approximate.
J = Estimated value. Analyte concentration below the calibration range. The concentration andidentification of the compound are tentative.
* The comparison values used in this Table are lifetime exposure levels set by the Drinking WaterHealth Advisories. They are based on a lifetime (70 years) at an exposure rate of 2 Liters of waterconsumption per day.
PMCL = EPA Proposed MCL
MCL = EPA Maximum Contaminant Level
CREG = Cancer Risk Evaluation Guide
The soil investigation conducted during the RI was performed to determine the nature and extent ofsoil contamination attributable to former disposal activities at the site. The RI concluded that on-sitecontaminants were present in the immediate vicinity of the disposal area. Contaminants were detectedprimarily in shallow soil. Contamination appears to be localized to the former disposal areas. Thehighest contaminant concentrations were detected in samples from the former lagoon areas.
During the RI, soil borings and test pits were positioned to investigate suspected lagoon and drumdisposal areas (Figure 5). The test pit program was designed to determine the potential presence andremaining concentrations of residual chemicals, if any, at the previous disposal and storage areas. Thesoil borings were drilled to investigate the vertical and horizontal extent of residual chemicals in thesoils.
The RI also included a series of sampling rounds (referred to as "surface soil" in the RI) of the toptwelve inches of soil. The referenced "surface soil" in the RI does not represent surface soil samplesas defined by ATSDR. Surface soil is defined by ATSDR to be soil from the top three inches of soilbecause this soil is considered the most likely depth that people would normally be exposed to. Thispublic health assessment has evaluated all the data presented in the RI and the sampling locations for"surface soils" is presented in Figure 6.
The primary contaminants found in this media were chlorinated aliphatic compounds (CACs) andsemi-volatile organic compounds (SVOCs). No vertical patterns of contaminant distribution areapparent. Elevated chemical concentrations were generally found in samples collected from depthsless than 17 feet (10). The 1983 site clean-up removed an unidentified amount of surface soil and isbelieved to have removed a major portion of the source material and contaminated soils. Table 3presents contaminants identified as being of concern in this media.
|Contaminant||Test Pits||Soil Borings||Comparison |
|Chloroethylene**||ND - 0.5 E||TP 3-1||ND||1 EMEG|
|Tetrachloroethene||ND - 61 E||TP 3-1||ND - 0.012||SB7|
|1,2,4-Trichlorobenzene||ND - 710 D||TP 3-1||ND - 12||SB3|
|ND - 161||TP 5-1||ND - 1.7||SB6|
|Contaminant||0 - 1 Foot Samples||Comparison|
|Chloroethylene**||ND - 0.21||HA-3||1 EMEG|
|Tetrachloroethene||ND - 0.69||HA-6||10,000EMEG|
|1,2,4-Trichlorobenzene||ND - 1.2||HA-11||500 RMEG|
|ND - 33 D||HA-6||50 CREG|
|PCB-1254||ND - 1.9||HA-8||10 EMEG|
** Selected due to the contaminant's cancer classification
D Sample diluted for this analysis
E Estimated Value. Analyte exceeded the calibration range. These values are approximate.
ND Not Detected
Groundwater - Private Wells
In June 1983, EPA detected methylene chloride (Figure 3) in four private wells (Wells 2, 3, 5, and6) in levels ranging from 10.9 to 16.2 µg/L (micrograms per liter). In July 1984, methylene chloride(678 µg/L) and 1,2-dichloroethane (2.51 µg/L) were detected in Well 2 which is approximately 125feet upgradient from the site. No contaminants were detected in wells 3, 5, and 6 at that time. In the1989-90 sampling, however, a monitoring well located between the site and Well 2 did not reveal thepresence of contaminants (10).
Hydrogeologic data indicate that the presence of compounds in Well 2 does not appear related to theMedley site because the well is upgradient of the site and no contaminants were detected in amonitoring well and two background wells located between Well 2 and the site. Water levelmeasurements in Well 2, the background wells (SW1 and BW1), and the piezometer locatednorthwest of the source area indicate that Well 2 and the background wells are hydraulicallyupgradient and have therefore not been impacted by the Medley site. SCDHEC has advised theprivate well owner that the well should not be used; the owner now uses municipal water. Privatewells have not been sampled since 1984.
No off-site soil samples were collected during the RI. Therefore, no data are available for review.
Surface Water and Sediments
Jones Creek serves as a discharge area of the Medley Farm site. No site-related contaminants weredetected in surface water samples or sediment samples from Jones creek. Sampling includedcollections of upstream and downstream sediments and surface water. Surface water was collectedprior to collecting stream sediment samples to avoid suspended sediments in the water samples. Downstream samples were taken first to avoid any potential impact from collecting the upstreamsamples (10).
The data in this section are from the February 1991 RI/FS. The conclusions drawn in this publichealth assessment are based on the assumption that the data and information presented in the RI/FSare reliable and valid. SCDHEC assumes that adequate quality assurance and quality controlmeasures were followed with regard to chain-of-custody, laboratory procedures, and data reporting.
The monitoring wells currently in use at the Medley site appear to be constructed according toSCDHEC standards to allow collection of representative groundwater samples.
We saw some abandoned vehicles and appliances behind the property owner's residence during the1988 and 1992 site visits, but these were not easily accessible to persons other than the residents. We noted no other hazards.
To determine whether nearby residents are exposed to contaminants migrating from the site, ATSDRevaluates the environmental and human components that lead to human exposure. This pathwaysanalysis consists of five elements: A source of contamination, transport through an environmentalmedium, a point of exposure, a route of human exposure, and an exposed population.
ATSDR categorizes an exposure pathway as a completed or potential exposure pathway if theexposure pathway cannot be eliminated. Completed pathways have all five elements and indicate thatexposure to a contaminant has occurred in the past, is currently occurring, or will occur in the future. Potential pathways, however, have at least one of the five elements missing, but it could exist. Potential pathways indicate that exposure to a contaminant could have occurred in the past, couldbe occurring now, or could occur in the future. An exposure pathway can be eliminated if at leastone of the five elements is missing and will never be present.
A past completed exposure pathway was identified for a private well user near the Medley site. Contaminants detected in this well were not considered to be site related. Potential exposurepathways have been identified for this site. In this section, we will discuss the potential for humanexposures to contaminants found in these media.
A past completed exposure pathway has been identified from a private well user in proximity to thesite. In 1983, SCDHEC advised the private well users to discontinue use of this well; they havecomplied. Contaminants detected in Well 2 are not considered to be related to previous activities atthe Medley site. Hydrogeologic data and the site topography indicate that groundwater flow on thesite is primarily to the southeast toward Jones Creek. This contamination is not considered to be siterelated. The length of exposure to contaminants from this source is not known and cannot beestimated; therefore, this past exposure pathway cannot be evaluated further.
|Exposure Pathway Elements||Time|
Exposure to groundwater off-site is not a pathway of concern at this time because the groundwaterplume containing site-related chemicals is presently confined to the site and local residents are notutilizing groundwater as a drinking water supply. Methylene chloride and 1,2-dichloroethane weredetected in Well 2; however, the owner was informed of this contamination, advised to discontinuewell use and has complied. Therefore, no exposures to contaminants from this well are currentlyoccurring or are anticipated to occur in the future. The contaminants detected in Well #2 are notconsidered to be site-related because topographic data indicate that the well is located upgradient ofthe site and hydrogeological data indicate that groundwater flow is to the southeast toward Jonescreek and not toward Well 2. Additionally, samples collected from monitoring wells located betweenWell 2 and the site do not show contamination. We recommend that other sources of contaminationin the area be characterized.
Hydrogeologic data presented in the RI indicate the contaminated groundwater plume does notunderlie any existing residential buildings. Samples collected in 1984 did not include contaminantsof concern. However, private well samples have not been collected since 1984 and this pathwaycannot be evaluated further at this time.
This potential exposure pathway could become a completed exposure pathway if the site becomesfurther developed and a private well is drilled and utilized on the site property. Exposures couldoccur through ingestion, inhalation of water vapors while bathing or cooking, and through dermalcontact with the contaminated groundwater from a private on-site well. We recommend thatSCDHEC restrict the issuance of well drilling permits for drinking water wells in this area.
Surface Water and Sediment Pathway
In 1990, very low levels of several contaminants were found in Jones Creek. The contaminantsdetected did not exceed ATSDR comparison values and are not considered to be of concern to thepublic at this time. Because the creek is not used as a drinking water source or for agricultural orindustrial purposes, the only potential for public exposure to surface water would be throughaccidental ingestion and skin contact. In the future, if contaminant levels in surface waters increase,adverse health effects may occur; however, this possibility is considered very unlikely at this time. Additional sampling data will be evaluated to better ascertain the possibility of exposures to thepublic.
Past, current, and future exposures to contaminated soil may have resulted at the Medley site. Whilethe future development of the site could lead to exposure pathways, we believe that only on-site areasrepresent likely points of exposure.
The migration of the residual chemicals in soil is insignificant on the site due to the site topography,limited access to the site, dense forests surrounding the site, the vegetative cover of the site, andlimited mobility of chemical residuals. There is no concern of soil erosion at this time due to thevegetative cover on the site and the dense forests that surround the site.
Topographic analyses indicate that surface soil contaminants could enter Jones Creek through runoffduring rain storms. However, sampling shows that no site-related contaminants have reached JonesCreek and no point of exposure exists from this medium.
Exposure to contaminants in soil is unlikely since these contaminants were detected in localized areasat depths greater than 1 foot and at 15 to 17 feet respectively. A number of contaminants have beendetected in shallow (0-1 foot) soil samples. There is no data available to indicate the concentrationof contaminants found within the top 3 inches of soil. Since most of the site is covered with weedsand grasses, with small areas of bare soil, exposures to these contaminants would be unlikely. Peoplemost likely to be exposed include the property owner's family (if they spend time on the site),trespassers, and hunters who may stray onto the property. The only possible route of humanexposure may be inhalation of chemical vapors during soil excavation activities. This is unlikely asthere are no excavation activities on site at this time.
No air monitoring data is available for review. Contaminants attached to soil particles could becarried by the wind. However, dust generation is unlikely because the site is surrounded by foreston three sides and there are few areas of exposed surface soil. In addition, there are no homes otherthan that of the property owner immediately adjacent to the site. Therefore, no evidence for transportof site-related contaminants through air exists.
Food Chain Pathway
Any potential exposures to site-related contaminants due to ingestion of blackberries or wild gamefound on site is unlikely. The site is covered by clean fill; and plants growing on clean fill should notbe able to access any site-related chemicals. Additionally, the site is not readily accessible to thegeneral public because of its remote location.
Jones Creek does not appear to be large enough for fishing. Contaminants have not been detectedin the creek at levels of concern.
Hunting is popular in the vicinity of the site, but substantial accumulation of contaminants in wildlifeis not likely. Wild game do not feed exclusively on the site. Surface clean-up has been thorough andsignificant surface water contamination has not been detected. Site-related contaminants are unlikelyto be transported via this pathway.
In this section we will discuss the health effects in persons exposed to specific contaminants, evaluatestate and local health databases, and address specific community health concerns.
To evaluate 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 therespective contaminant below which non-cancer, adverse health effects are unlikely to occur. MRLsare developed for each route of exposure, ingestion, inhalation and dermal contact, and for threedifferent lengths of exposure, acute (less than 14 days), intermediate (15 to 365 days) and chronic(greater than 365 days). ATSDR presents these MRLs in Toxicologic Profiles. These chemical-specific profiles provide information on health effects, environmental transport, human exposure, and regulatory status.
A past completed exposure pathway has been identified for one private well user located upgradientfrom the site. This contamination is not considered to be site related, the length of exposures is notknown, there are no data available for review, and the private well user has discontinued use of thewell; therefore, this pathway cannot be evaluated for past exposures and no current exposures areknown to be occurring.
Currently available data show no completed pathways to be occurring at the present time. Exposuresto contaminated groundwater could occur in the future if private wells are drilled on the site propertyor in the vicinity of Well #2. The future residential development of the site should be monitored toprevent exposures to contaminants in the future. If the future residential development is notrestricted, persons may be exposed to contaminated drinking water. Therefore, this section explainsthe health implications of ingesting contaminants at the maximum concentrations detected in soil,groundwater, surface water and sediments. Because this is a hypothetical exposure based onassumptions of groundwater movement and human activities at the site, the discussion is brief.
The information provided in this section is based on estimated doses that are derived followingseveral standardized assumptions. These estimated doses are computed estimations of the amountof chemicals a person can be exposed to. The computations are based on the assumptions that anadult weighs 70 kilograms (154 pounds) and a child weighs 10 kilograms (27 pounds). An adultingests 2 liters of water per day, and a child drinks half that amount. During the course of the day,adults typically ingest 50 to 100 milligrams of soil per day (mg/day); by inhalation of small soilparticles carried in the air, and by placing soiled hands and other objects in the mouth. We assumethat small children ingest a greater amount of soil, typically 200 mg/day, because they generally tendto place objects in their mouths.
These assumptions and the respective exposure scenarios are used to determine the estimated dosesfor each chemical. The estimated doses will be compared to health guidelines and the availablescientific literature to determine if health effects are likely to occur.
No exposures to benzene are occurring at the present time; therefore, no health effects are expected. If on-site groundwater is used as a drinking water source, the amount of benzene that would beconsumed would result in an increased risk of developing cancer. The EPA classifies benzene as aknown human carcinogen (1).
Chlorinated Aliphatic Compounds (CACs)
This class of chemicals includes methylene chloride, chloroform, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1-dichloroethylene, and trichloroethylene (Table 2).
As these compounds exhibit similar toxicologic and chemical properties, one may assume that amixture of these compounds is at least as toxic as the effects of each compound. Evidence inlaboratory animals indicates that, for some limited combinations of these compounds, the toxicity ofthe mixture is greater than would be expected from the toxicity of each compound (2,3,4,5,6).
The ingestion of small amounts of these compounds over a prolonged period of time may lead todamage of the liver and kidneys. The compounds whose names contain "ethane" appear less likelyto produce kidney damage. The EPA classifies several compounds in this class as probable humancarcinogens (Group B2). A Group B2 classification is used to characterize a chemical for which thereis sufficient evidence of carcinogenicity in animals but inadequate evidence or no data from humanepidemiological studies (2,3,4,5,6). These include methylene chloride and chloroform. The EPAclassifies 1,1,2-trichloroethane as a possible human carcinogen (5).
If on-site groundwater was used as a drinking water source, the amount of each contaminantconsumed would exceed ATSDR minimal risk levels. Hypothetically, individuals consuming thiswater could develop noncarcinogenic health effects (that is, liver, kidney, and possibly nervous systemdamage).
Since these compounds are mainly probable human carcinogens, individuals who consume this waterwould have an increased risk of developing cancer. However, currently there is no consumption ofon-site water and based on available information there is no exposure to this group of contaminants.
Semi-Volatile Organic Compounds
1,2,4-Trichlorobenzene was found at a concentration of 710 mg/kg (milligrams per kilogram) insamples of the test pits. This concentration however, has been diluted for this analysis. Thiscompound was also found in soil borings of 15-17 feet at a maximum concentration of 12 mg/kg ofsoil. In addition, 1,2,4-trichlorobenzene was found in the samples taken from 0-1 feet range at aconcentration of 1.2 mg/kg (10).
Since exposures to this compound are unlikely to occur, it is not considered a health threat at thistime. Available information on the toxicological properties and the long-term health impact ofexposure to 1,2,4-trichlorobenzene is limited (11). EPA has not classified this chemical as to humancarcinogenicity.
As no health outcome data exists for the Medley site, health outcome data cannot be evaluated at thistime.
The community expressed concern about possible contamination of their water supplies and the healtheffects that may occur from this contamination. We responded to these concerns by sampling thewater supply wells in 1984. The only well that showed contamination is Well 2 locatedapproximately 125 feet upgradient of the site (Figure 3). Groundwater monitoring conducted in 1989- 1990 of a monitoring well located between the well of concern and the site showed nocontaminants. Well 2 contamination is not considered site-related as it is located upgradient of thesite and a monitoring well located between the well and the site showed no contaminants. The ownerof Well 2 was advised to discontinue use of the well and is now using municipal water.
Since the other private wells showed no contaminants of concern, they are not considered to be ahealth risk at this time. Municipal water supply lines are now available to the community and nofurther concerns have been expressed.