PUBLIC HEALTH ASSESSMENT ADDENDUM
CAROLAWN
FORT LAWN, CHESTER COUNTY, SOUTH CAROLINA
ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
This section is based on the data generated in the Phase I and Phase II Remedial Investigation (RI). These investigations represent the most recent and complete set of data. Sampling results relevant to public health implications are also presented here. A complete analysis of historical data may be found in the August 1988 Health Assessment.
The tables in the section list the contaminants of concern. We evaluate these contaminants in the subsequent sections of this Public Health Assessment and determine whether exposure to them has public health significance. This Public Health Assessment selects and discusses these contaminants based upon the following factors:
In the data tables that follow under the On-site Contamination subsection and the Off-site Contamination subsection, listing a contaminant does not mean that it will cause adverse health effects from exposures. Instead, the list indicates which contaminants will be evaluated further in this Public Health Assessment. When selected as a contaminant of concern in one medium, that contaminant will be reported in all media.
The data tables include the following acronyms:
| CREG EMEG MCLG MCL PMCLG PMCL RfD |
= 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 specific media that are used to screen and select contaminants for further evaluation. These values include EMEGs, CREGs, and other relevant guidelines. CREGs are estimated contaminant concentrations based on a one excess cancer in a million persons exposed over a lifetime. CREGs are calculated from EPA's cancer slope factors. EPA's MCLG is a drinking water health goal. EPA believes that the MCLG represents a level that no known or anticipated adverse effects on the health of persons should occur which allows an adequate margin of safety. PMCLGs are MCLGs that are being proposed. MCLs represent contaminant concentrations that EPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an exposure rate of 2 liters 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 adverse health effects.
Toxic Chemical Release Inventory (TRI)
The Carolawn Company ceased operation before the initiation of the EPA Toxic Chemical Release Inventory (TRI). Therefore, no TRI records are available for this site. Additionally, 1988 TRI records do not list any other facilities within a 1-mile radius between latitudes 34º 40' 10" and 34º 42' 10" north and longitudes 80º 55' 24" and 80º 57' 36" west.
Groundwater - Monitoring Wells
Figure 3 shows the location of the monitoring wells and residential wells. The Phase I RI collected groundwater samples from four monitoring wells and four off-site residential wells in July 1986, and from the four monitoring wells and two residential wells in December 1986. The residential wells will be discussed in the off-site contamination section.
Phase II sampling analyzed all groundwater monitoring wells and a residential well for volatile organic compounds (VOCs). The first round of samples were taken in late August and early September, 1988. The second round were taken in October 1988. The laboratory analyzed all samples for VOCs. The samples from MW-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 of concern detected in the monitoring wells. The RI notes that groundwater samples were neither filtered nor decanted in either the field or laboratory. In the 1986 sampling results of Phase I of the RI, concentrations of several heavy metal concentrations exceeded EPA Maximum Contaminant Levels (MCL). In the 1988 Phase II's first round of sampling, only chromium and lead concentrations exceeded their MCLs; no heavy metals exceeded their MCLs in the second round of Phase II sampling. The RI attributes this to the amount of purging of the wells which in the later sampling rounds resulted in sediment-free samples. VOCs were detected in both sampling rounds in excess of their MCLs.
PCBs and Pesticides were not detected in on-site groundwater samples.
TABLE 1
CONTAMINANTS OF CONCERN
GROUNDWATER MONITORING WELLS
REMEDIAL INVESTIGATION REPORT, 1986 AND 1988
CAROLAWN SITE, FORT LAWN, SOUTH CAROLINA
| Concentration On-Site |
Range (mg/L) Off-Site |
Comparison Value |
|
| INORGANIC COMPOUNDS | |||
| ARSENIC EMEG |
ND - 0.022 | *** | 0.01 |
| CHROMIUM (VALENCE UNKNOWN) EMEG |
ND - 0.12 | *** | 0.05 |
| LEAD PMCL |
ND - 0.08 | *** | 0.005 |
| ORGANIC COMPOUNDS | |||
| ACETONE | ND - 31 | ND - 9.2 | 1.0 RfD |
| DICHLOROMETHANE CREG |
ND - 0.009 B | ND - ND | 0.005 |
| 1,1-DICHLOROETHYLENE MCLG |
ND - 0.170 | ND - 0.016 | 0.007 |
| 1,2-DICHLOROETHYLENE MCL** |
ND - 0.467 | ND - 0.47 | 0.07 |
| TRICHLOROETHYLENE CREG |
ND - 1.2 | ND - 0.62 | 0.003 |
| BIS(2-ETHYLHEXYL)PHTHALATE* CREG |
ND - 0.35 | 0.003 |
ND - Not Detected
B - Compound was also detected in the associated laboratory
blank. This detection may represent a laboratory
artifact.
* - 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 FOR
OFF-SITE MONITORING WELLS.
Soil
The Phase I RI collected "surface" and subsurface soil samples (Tables 2 and 3). Composite "surface" soil samples came from four zones within the fenced area and on-site zones outside of the fenced area to the west and north; the RI does not indicate the depth of the composite "surface" soil samples. Therefore, this Public Health Assessment will refer to these as shallow soil samples; this will distinguish these samples from surface soil samples taken from the upper three inches of soil. The highest concentrations of several contaminants occurred in composite sample CLSS-101E in an area immediately west of the fence.
Subsurface soil samples came from seven soil borings: four within the fenced area, one west of the fenced area, and two north of the fenced area.
During the week of December 10, 1990, EPA collected 21 subsurface soil samples from nine soil borings from the areas west and north of 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 organic compounds.
Organic compounds detected included low levels of acetone, 1,2-dichloroethylene, 2-butanone, toluene, xylene, and miscellaneous extractable compounds. Surface soil samples were not taken. As the concentrations of these organic compounds were very low, organic compounds in this sampling round will not be considered further.
Groundwater - Private Wells
This section details groundwater data from the four nearby residential wells. Table 4 summarizes the VOCs detected in these four residential wells. Table 1 also summarizes data from off-site monitoring wells; these monitoring wells are not being used as a source of potable water.
Residential well RW-1 was the earliest well to show contamination and consistently shows the highest concentration of contaminants. This well is considered to be within the contaminant plume. The well 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 sample the well, it has obviously not been abandoned. (In this Public Health Assessment, abandoning a well means properly removing and sealing a well according to applicable laws.)
TABLE 2
CONTAMINANTS OF CONCERN
SHALLOW SOIL ANALYSES
CAROLAWN SITE, FORT LAWN, SOUTH CAROLINA
| RANGE (MG/KG) |
COMPARISON VALUE |
||
| INORGANIC COMPOUNDS | |||
| ARSENIC | 3.2 - 7.5 | 2 - 700 | EMEG |
| CHROMIUM | ND - 93 | 10 - 3000 | EMEG |
| LEAD | ND - 160 | 250 | ATSDR |
| ORGANIC COMPOUNDS | |||
| 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 |
| TRICHLOROETHYLENE | ND | 63 | CREG |
| 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.
TABLE 3
CONTAMINANTS OF CONCERN
SUBSURFACE SOIL ANALYSES
CAROLAWN SITE, FORT LAWN, SOUTH CAROLINA
| RANGE (MG/KG) |
LOCATION OF MAXIMUM |
DEPTH OF SAMPLE (FEET) |
|
| INORGANIC COMPOUNDS | |||
| 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 | ||
| ORGANIC COMPOUNDS | |||
| ACETONE | ND | ||
| DICHLOROMETHANE | ND - 0.01 | SB-2 | 3.0 - 5.9 |
| 1,1-DICHLOROETHYLENE | ND | ||
| trans-1,2-DICHLOROETHYLENE | ND | ||
| TRICHLOROETHYLENE | ND | ||
| 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 be
disturbed, the comparison values would be the same as listed in
Table 2.
TABLE 4
CONTAMINANTS OF CONCERN
PRIVATE RESIDENTIAL WELLS
PHASE I AND PHASE II REMEDIAL INVESTIGATION
CAROLAWN SITE, FORT LAWN, SOUTH CAROLINA
| Concentration Range (mg/L) |
Occurrence of Maximum |
Comparison Value |
|
| INORGANIC COMPOUNDS | |||
| ARSENIC EMEG |
ND | 0.01 | |
| CHROMIUM EMEG |
ND - 0.016 | RW1, 07/86 | 0.05 |
| LEAD PMCL |
ND - 0.02 | RW1, 07/86 | 0.005 |
| ORGANIC COMPOUNDS | |||
| ACETONE | ND | 1.0 RfD | |
| DICHLOROMETHANE CREG |
ND - 0.007B | RW1, 12/86 | 0.005 |
| 1,1-DICHLOROETHYLENE MCLG |
ND - 0.005 | RW1, 12/86 | 0.007 |
| trans-1,2-DICHLOROETHYLENE MCLG |
ND - 0.84 | RW1, 12/86 | 0.1 |
| TRICHLOROETHYLENE* CREG |
ND - 0.32 | RW4,08-09/88 | 0.003 |
| BIS(2-ETHYLHEXYL)PHTHALATE CREG |
ND | 0.003 | |
Residential well RW-2 sits south of the site. The December 1982 sampling results for metals and VOCs did not show the presence of site-related contaminants. Zinc was detected at a concentration of 30 mg/L. April 1985 sampling showed low concentrations of dichloromethane (0.0022 mg/L) and tetrachloroethylene (0.0025 mg/L). VOCs were not detected in the July, 1986 samples. Problems with quality control place doubt on analyses of December 1986.
According to a telephone interview with a local resident, RW-2 is not presently used as a drinking water source because they tied on to municipal water in 1985. However this well has not been properly abandoned since samples were able to be collected from this well. The RI stated that the pump could not be removed from this well.
RW-3 sits southwest of the site. In a telephone interview, a resident stated that this house has not tied on to municipal water. December, 1982 sampling results for metals and VOCs did not show the presence of site-related contaminants. April, 1985 sampling 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 and laboratory data included questionable Quality Assurance and Quality Control, the owners of RW-3 elected not to tie-on to municipal water in 1985. The July, 1986 sampling results did not detect 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 was analyzed for inorganic elements, purgeable organic compounds, extractable organic compounds, and pesticides. Because chlordane-related compounds were detected, a second sample from December 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 and VOCs did not show the presence of site-related contaminants. The house associated with this well burned down in approximately 1988. The Remedial Investigation indicates that trichloroethylene was detected at a concentration of 270 mcg/L during Phase II sampling. However, the narrative indicates that only well RW-1 was sampled; the laboratory reports only denote that this was a residential well. Because of the lack of a plausible environmental pathway to RW-4, confusion arising from the frequent changes in the well numbering scheme between various historical reports, and the presence of this contaminant at a similar 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 not consider health implications from any contaminants in this well. However, since it has not been properly abandoned, we may need to reconsider this opinion should it be used as a household water source in the future.
TABLE 5
CHLORDANE-RELATED COMPOUNDS DETECTED IN RESIDENTIAL WELL RW-3
SEPTEMBER AND DECEMBER OF 1989
| 09/28/89 | 12/15/89 | |
| CHLORDANE | 0.014 | 0.012 |
| ALPHA-CHLORDANE | 0.014 J | 0.013 J |
| BETA-CHLORDANE | ND | 0.062 |
| GAMMA-CHLORDANE | 0.12 N | 0.12 |
| 1-HYDROXYCHLORDENE | 1.1 N | 0.84 |
| GAMMA-CHLORDANE | 0.24 J | 0.19 |
| TRANS-NONACHLOR | 0.073 | 0.062 |
| ALPHA-CHLORDANE | 0.17 J | 0.17 |
| CIS-NONACHLOR | 0.020 J | ND |
| OXYCHLORDANE | 0.13 N | ND |
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
Soil
No off-site soil data has been located. Sampling of soil outside of the fenced area but on the original site property is contained in the above section on on-site soil contamination.
Surface Water
The Phase I RI collected surface water samples from the intermittent stream leading away from the site, Fishing Creek upstream of the site, and Fishing Creek downstream of the site. Upstream and downstream samples contained comparable concentrations of metals. Low levels of dichloromethane, i.e., 0.003 mg/L, appeared in the samples from Fishing Creek downstream of the site. However, dichloromethane is also a common laboratory contaminant; the detection of dichloromethane in surface water may have been spurious.
The Phase II RI collected surface water samples from Fishing Creek both upstream and downstream of the site. They were analyzed for VOCs listed on the Target Compound List (TCL). Only low levels of acetone were detected (0.091 mg/L). Acetone was not detected in the laboratory duplicate. Groundwater samples show much larger concentrations of acetone. Therefore, the detection of acetone may represent a true detection.
Stream Sediments
The Phase I RI collected stream sediments from the drainage courses leaving the site, from the intermittent stream and from Fishing Creek. The sediments were assayed for EPA Priority Pollutants. Metal concentrations within these samples were within natural background levels. Both dichloromethane (0.0061 to 0.021 mg/kg) and acetone (0.0059 to 0.045 mg/kg) were also detected in the associated laboratory blanks; therefore the detection of these compounds may represent normal laboratory error. However, the detection of acetone may also represent a true detection for the factors enumerated in the above paragraph. No other compounds were detected.
C. Quality Assurance and Quality Control
The Remedial Investigation Report, Appendix F, contains the Conestoga-Rovers & Associates Phase II validation reports. The Round I groundwater monitoring report cited the use of a relatively small number of blanks and a lack of a surrogate compound for Pesticide and PCB analysis. However, it concluded that the data were acceptable and complete. The Round II groundwater monitoring report concluded that the data had excellent precision and accuracy. However, metals were found in the method blanks at levels high enough to interfere with the reporting of metals in the associated samples.
Also, the data validation reports do not mention the high detection limits for many volatile organic compounds in groundwater samples. Because of the high detection limits, other compounds could have been present but not detected.
The RI Report does not explicitly define the depth from which shallow soil samples were taken. In determining the probable health effects which may occur at this site, people are most likely to come into contact with soils from the upper few inches of soil. Also, contaminants in the superficial soil are most likely to be spread via surface runoff or airborne depositions should the site surface be disturbed.
The appearance of trichloroethylene in RW-4 needs further investigation. Specifically, this well lies approximately 0.7 miles west of the site. This is away from the direction of groundwater flow. This sample may have actually been drawn from well RW-1 (see above).
In preparing a public health assessment, ATSDR and SCDHEC rely on the accuracy, precision, and completeness of the supplied data. It is assumed that standard protocols were followed for chain of custody, laboratory procedures, and data reporting.
In general, the site consists of a forest and a fenced field covered with weeds. Access to the fenced area is easily gained through the bent southern gate, spaces between the southeastern fence and the ground, and the spaces both under and between the two arms of the northern gate.
Naturally-occurring physical hazards consist of the flora and fauna indigenous to and/or established in the area. This includes fire ants and other stinging insects, snakes, and poison ivy.
Man-made physical hazards include the remaining incineration
equipment, discarded industrial trash, and rectangular ponds of
approximately 6 inches in depth and 5 feet in length.
To determine whether nearby residents and workers are exposed to contaminants migrating from the site, ATSDR evaluates the environmental and human components that lead to human exposure. This pathway analysis consists of five elements: a source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and an exposed individual or population.
ATSDR identifies exposure pathways as completed, potential, or eliminated. For a completed pathway to exist, all five elements must exist and exposure to a contaminant must have occurred in the past, is presently occurring, or will occur in the future. For a potential pathways to exist at least one of the five elements is missing, but could exist. Potential pathways indicate that exposure to a contaminant could have occurred, could be occurring, or could yet occur. A pathway is eliminated when at least one of the five elements is missing and will never be present. The following discussion is limited to pathways important and relevant to the site.
A. Completed Exposure Pathways
At the Carolawn Site, environmental sampling data document that past waste storage and disposal activities have contaminated soil and groundwater. It is possible that past disposal activities may have also led to atmospheric contamination; however, this route of exposure cannot be assessed due to a lack of environmental data. There are currently no completed exposure pathways at this site. Considering the contaminated media, the extent of contamination, and the area demographics, no persons are currently exposed to site-related contaminants.
B. Potential Exposure Pathways
The major potential routes of future human exposure include the ingestion of on-site soil and ingestion of groundwater. There is the potential for exposures to occur by trespassing on the site and through the ingestion of chlordane-related compounds from well RW-3. Due to the potential for exposure, three scenarios will be considered in the Public Health Implications section of this report. First, the ingestion of water from well RW-3 which is occurring. Secondly, because of the possibility of future development at this site, the ingestion of maximally contaminated soil can be anticipated to occur in the future. Third, the likely ingestion of maximally contaminated groundwater. This exists because of the possibilities for contamination of well RW-3, the use of well RW-1 for ingestion, and the installation of a new residential well in the contaminated area. Although current evidence indicates that well RW-1 is not being used, this third scenario conservatively estimates the risk of either using well RW-1 or any other future wells within the path of contaminant migration. A fourth scenario could be exposure through the food chain, however, since exposure is unlikely, this scenario will not be discussed in the Public Health Implications section.
Groundwater Pathway
| 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 vapors arising from contaminated groundwater underlying 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. This route of exposure is considered potential because of the uncertainties in the area hydrogeology and the lack of institutional controls against the drilling of new wells.
The site is located in an area known to geologists as the eastern Charlotte Belt of the Piedmont Physiographic Province of South Carolina. The Charlotte Belt consists of high-grade metamorphic rocks which have weathered to saprolite. The saprolite thickness varies from a few feet to approximately 150 feet.
Surficial soil observed at the site consists of brown silty sand and clay. The soil thickens toward Fishing Creek with a maximum observed thickness of 15.7 feet along the creek, southeast of the site.
Saprolite, formed by the weathering of bedrock, lies beneath the soil. The saprolite observed at this site is primarily a clayey, silty sand. The thickness of saprolite varies across the site from less than 5 feet to approximately 30 feet.
The depth of bedrock at this site varies from 4.5 feet below the land surface (bls) to 38.5 feet bls. The bedrock consists of granodiorite, a granite-like rock, intruded by a number of dikes. Within the bedrock, two major sets of joints and three sets of fractures have been identified. Both the joints and fractures appear to have approximately vertical dips. These features indicate that local groundwater flow may be complex within the bedrock.
Groundwater beneath the site occurs in the bedrock along joints and fractures. Water levels are less than 10 feet below the ground surface (bls) near Fishing Creek and deeper than 40 feet bls at the site area. Based on three rounds of water-level measurements, groundwater generally flows in an eastward direction beneath the site, with southeast and northeast components of flow toward Fishing Creek. Calculations, based on field data, estimate that the groundwater flows at a rate of 204 feet per year. However, joints and fractures may create local deviations 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 steadily toward Fishing Creek from the site area.
Groundwater sampling shows the presence of contaminants in on-site monitoring wells, off-site monitoring wells, and off-site private wells. Available data indicates that only one private well remains in use as a potable water source although all four wells remain operational.
Currently available data indicate that the contaminated groundwater moves towards the northeast, southeast, and east. This plume moves under private residence RW-1.
Data prior to 1985 indicate the sporadic presence of volatile organic contaminants in the other private wells RW-2, -3, and -4. This may also indicate laboratory error and/or sampling technique.
Residential well RW-1, southeast of the site, has consistently shown high levels of contamination with significant concentrations of volatile organic compounds (VOCs). The owner of this well stated in August 1984 that he gets his drinking water from a well away from the site. Recent studies used RW-1 for sampling. The well has not been abandoned. Should this well be used in the future, exposure from this source would have to be reassessed.
A December 23, 1986 ATSDR memorandum stated, "The most significant human health threat posed by this site is from the chronic consumption of contaminated groundwater. EPA's 1985 extension of city water lines to the three affected wells has eliminated this exposure pathway for the three families living near the site." However, this conclusion is not completely correct in that one family elected not to use municipal water.
Original data indicated that all three residences and also RW-4 had connected to the municipal water supply in 1985. Yet, in 1989, one of the residents stated that they still used their well as a sole source of household water. Subsequent retesting of this well only showed the presence of chlordane-related compounds which appeared unrelated to the site (see Off-Site Contamination). However, fractured bedrock underlies the site. Fractures may direct contaminated groundwater in directions different than the superficial groundwater flow. Therefore, the possibility of future contamination with site-related contaminants in the residential well RW-3 cannot be ruled out.
As stated in the section on QA/QC, the appearance of trichloroethylene in RW-4 warrants further investigation. For the reasons listed in the Off-Site Contamination section, this sample may have actually been drawn from well RW-1. In either event, 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 be considered further in this report.
Besides ingestion, exposures to VOCs in groundwater can also occur through dermal contact (such as in bathing), and through inhalation (such as in showering and cooking). Because contaminated groundwater underlies the residence at RW-1, VOCs could volatilize into the house. Data are not available for the evaluation of these other pathways of exposure.
Soil Pathway
| EXPOSURE PATHWAY | Soil |
| 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 not trespassing. |
Both on-site shallow soil samples and on-site subsurface soil samples have shown the presence of contamination. The RI Report does not indicate the depth from which the shallow soil samples were taken. In general, a person is only likely to come into contact with the upper 3 inches of undisturbed soil; therefore, only this upper soil layer is relevant to the current public health implications at a site.
Off-site soil samples and background soil samples are not available. The thick cover of weeds over the site would tend to limit the spread of soil by wind. Therefore, off-site concentrations of soil contaminants are likely to be less than on-site concentrations. Past agricultural practices may have caused increased concentrations of lead and arsenic throughout the 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 in subsurface soils, however, may be monitored to follow the movement of contaminants through the soil, may serve as sources of continued contamination, and may become relevant to public health in the future should activities disturb the soils at this site.
Erosion, which SCDHEC staff observed in the northeast corner of this site, could lead to the spread of both surface and subsurface soils into the neighboring creek system. Sampling of the nearby creek system, however, has not indicated that this is or has been occurring in significant amounts.
The incidental ingestion of soil is an important route of exposure, particularly for children less than six years old (EPA Exposure Factor Handbook). Young children ingest significant amounts of soil as a result of their normal hand-to-mouth activities. Adults and older children ingest less. Because a person could easily gain access to the site, ingestion of on-site shallow soil will be considered. However, since toys and other signs of children were not noted in the residences adjacent to the site and SCDHEC staff have not noted definitive signs of trespass on the site, this pathway is not likely to be occurring and will be considered a potential pathway.
Food Chain
| 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 possibility
in 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 gardens
exposed to smoke and debris in November 1979. Use of groundwater
for irrigation is possible. Ecologic data for Fishing Creek are
not available. Hunting and fishing activities are unknown.
Staff noticed various edible plants and animals during the site
visit.
Introduction
In this section we will discuss the health effects which may impact on people exposed to site-related contaminants. To evaluate health effects which may result from an exposure, ATSDR has developed Minimal Risk Levels (MRLs). MRLs estimate an exposure which is not likely to cause deleterious health effects; exposure to even lower amounts would be even less likely to cause adverse health effects. MRLs are specific to the route of exposure and the length of exposure. Routes of exposure may include ingestion (eating and drinking), inhalation (breathing), and dermal absorption (absorption through the skin). The duration of exposure is commonly classified as acute (less than 14 days), intermediate (15 to 364 days), and chronic (greater than 365 days) exposures.
ATSDR developed MRLs to assess the possible toxicity of compounds to body organs. MRLs do not include information on the potential of compounds to cause cancer. In general, we assume that a person exposed to small amounts of a carcinogenic compound will incur a small increase in the statistical probability of developing cancer. A person exposed to larger doses of the compound will incur a larger increase in the statistical probability of developing cancer.
This Public Health Assessment expresses the additional probability of developing cancer as a result of an exposure to a chemical in terms of no increased risk, no apparent increased risk, a low increased risk, a moderate increased risk, and a high increased risk. EPA has developed a mathematical methodology for estimating the extreme maximum probability that a person will develop cancer as a result of exposure to a chemical. The EPA Risk expresses estimates in the corresponding terms of less than one-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 chemical contaminants commonly found at hazardous waste sites. These documents provide information on health effects, environmental transport, human exposure, and regulations affecting these substances.
The human exposure pathways section of this Public Health Assessment lists the routes by which site-related contaminants may enter the human body. As stated above, an evaluation of these hazards relies on an accurate estimation of the amount of these chemicals to which a person may be exposed. This estimate will use several standardized assumptions.
We will assume that an adult weighs 70 kilograms (154 pounds) and a child weighs 10 kilograms (27 pounds). An adult ingests 2 liters of water per day (2 L/day, the same as a 2-liter soda bottle). A child drinks half that amount (1 L/day). During the course of the day, adults typically ingest 50 to 100 milligrams of soil per day (mg/day); this occurs by both inhaling small soil particles carried in the air and by placing soiled hands and other objects in the mouth. Because small children typically place objects in their mouths, it is assumed that they ingest a greater amount of soil, typically 200 mg/day.
Because neither off-site soil sampling data nor on-site surface soil data are available, the ingestion of on-site subsurface soil will 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 Exposure Pathways section.
INORGANIC COMPOUNDS
Arsenic
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 of this century. The combustion of fossil fuels and the smelting of metals also release a significant amount of arsenic to the atmosphere.
Ingestion of arsenic may lead to irritation of the gastrointestinal tract, toxicity of the nervous system, changes in the number of blood cells, and damage to the liver and kidney. Arsenic intake may lead to characteristic skin changes. Arsenic consumption has been reported to increase the risk of cancer of the skin, liver, bladder, kidney, and lung.
At the Carolawn site, sampling detected arsenic in shallow and sub-surface on-site soils. Sampling did not detect arsenic in groundwater. 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 Implications section introduction may be used to calculate a maximum dose resulting from the ingestion of subsurface soil. Comparing this dose to Figure 2.5 of the ATSDR Toxicological Profile for Arsenic, this hypothetical dose is less than the ATSDR Minimal Risk Level (MRL). Therefore, no significant health threat is anticipated, other than an increased cancer risk. Additionally, this dose would result, at most, in a low increased risk of cancer over the course of a lifetime.
Chromium
Chromium is a naturally occurring element found in three different valence states: chromium 0, chromium III (trivalent chromium), and chromium VI (hexavalent chromium). In nature, most chromium is trivalent. Chromium is used to make steel and other alloys, bricks for metallurgical furnaces, chrome plating, pigments, leather tanning, wood treatment, and water treatment.
Chromium III is an essential nutrient that helps to maintain normal metabolism of glucose (sugar), cholesterols, and fat in humans. The National Academy of Sciences Drinking Water and Health (Volume 3, page 367) states: "Compounds of chromium in the trivalent state have no established toxicity. When taken by mouth they do not give rise to local or systemic effects and are poorly absorbed. No specific effects are known to result from inhalation. In contact with the skin they combine with proteins in the superficial layers, but do not cause ulceration."
Chromium VI is irritating to the skin and nasal passages. In the body it attacks the liver, kidney, and central nervous system. Inhalation of high levels of hexavalent chromium has been associated with an increased risk of lung cancer in humans.
At Carolawn, sampling has not determined if the chromium is present in the trivalent or hexavalent state. Because of the differences in health effects between chromium III and chromium VI, no further statement may be made about the probable health effects resulting from chromium at this time.
Lead
Lead is a naturally occurring element which may be found in most environmental media. Lead has a wide range of uses including storage batteries (automobile batteries), solders, pipes, various chemicals, and gasoline additives.
Although lead may cause both acute and chronic effects, major concern has been focused on two chronic effects of lead toxicity. Chronic lead toxicity is associated with irreversible central nervous system and peripheral nervous system damage in children; this may express itself as difficulty in learning. Lead exposure may also be associated with anemia. Lead toxicity is also associated with hypertension in adult males, although studies disagree as to whether this effect is more pronounced in white or black males.
ATSDR has not set an MRL for lead. EPA has not set a reference dose (RfD) for lead. Although exposure to lead salts has been associated with an increased rate of cancer in laboratory animals, EPA has not set an estimate of the carcinogenic potency of lead.
Private well RW-3 is used as a potable water source. Sampling of this well does not show the presence of lead in excess of health based standards. Therefore lead toxicity is not reasonably expected at the present time from the ingestion of this water.
Concentrations of lead found in groundwater monitoring wells exceed the EPA action level. Therefore the future use of private well RW-1, the future installation of a private well in the contaminated area, or the migration of contaminants to currently used private well RW-3 could be expected to lead to the development of nervous system toxicity in children, anemia, and possibly high blood pressure in adults.
ORGANIC COMPOUNDS
Chlordane and Related Compounds
Sampling of private well RW-3 showed the presence of low levels of chlordane in off-site groundwater. The Phase I Remedial Investigation (RI) did not show the presence of chlordane in pesticide samples from on-site monitoring wells. Therefore the presence 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 related chemicals. It is used mostly to protect houses from termites and to protect corn and other crops from insects. (The owners of well RW-3 state that their house was last treated for termites around 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 uses above the ground in 1983, any chlordane that had already been bought or was still on the store shelves could be used above the ground until April 1988. Beginning in the fall of 1987, chlordane could only be used outside of buildings to control termites.
Laboratory animals ingesting low amounts of chlordane for a prolonged time period have developed changes in the liver, kidneys, and digestive tract. As RW-3 represents both the only home not using municipal water and the only detection of chlordane, exposure to chlordane appears limited to this household. The total concentration of chlordane related compounds in this water was 0.0019 mg/L. Ingestion of this water results in a dose which is less than the ATSDR Minimal Risk Level for chlordane (ATSDR Figure 2.2). An adult ingesting this water would 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 be expected to occur as a result of ingesting this water.
Oral exposure to high levels of chlordane for a prolonged period of time was associated with an increased rate of hepatocellular carcinomas in mice. Studies in rats have not shown an increased rate of cancer. Mutagenicity tests have generally not shown damage to DNA. Studies of humans working in the manufacture of chlordane have not shown an increased rate of cancer. Therefore, EPA classifies chlordane as a probable human carcinogen. Based on animal studies, the ingestion of water containing 0.0019 mg/L of chlordane for a lifetime could result in a low increased risk of developing cancer (ATSDR Figure 2.2). As it is unlikely that the residents have ingested this compound for a lifetime, the actual risk to these two people would be even less.
Acetone
Acetone is a clear, colorless liquid with a characteristic fruity odor. It is a natural part of the human body's chemistry as well as a natural substance in other animals, plants, and insects. Industrially, acetone is a solvent used in a wide variety of applications.
Acetone's toxicity is similar to the toxicity of ethyl alcohol. High concentrations of vapors may irritate the eyes and nasal passages. Systemic symptoms of acute exposure to high levels of acetone simulate ethyl alcohol intoxication. Exposure to lower levels for 90 days has produced damage to the liver and kidneys of rats.
ATSDR has not authored a Toxicological Profile for Acetone. EPA has set an oral Reference Dose (RfD) of 0.1 mg/kg/day, citing damage to the liver and kidneys of rats as the most sensitive effect of acetone toxicity.
At Carolawn, sampling detected acetone in shallow soil and groundwater. The trace amounts of acetone detected in soil are below levels which would indicate a public health concern. Additionally, available evidence indicates that the area of contaminated groundwater is not currently used as a potable water source. Both of these facts indicate no likelihood that health effects from acetone are occurring at the present time. However, as acetone is highly volatile and the area of contaminated groundwater underlies a residence, the possibility of acetone vapors in this residence should be considered. Air data from inside this home is not available.
Ingestion of contaminated groundwater can be considered as a future possibility. This is possible in the event that extant private well RW-1 should be again used as a private water source, another potable well is placed within the contaminated area, or the unlikely event that on-site contaminants migrate to the currently used well (RW-3). An adult ingesting water containing 31 mg/L of acetone would receive a dose approximately ten times the EPA RfD. A child ingesting the same water would receive a dose thirty times the RfD. Damage to the liver and kidneys could result.
1,1-Dichloroethylene
1,1-Dichloroethylene (1,1-DCE) is a chemical used to make various other 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-DCE does not exist; the probable toxic effects in humans are derived from both the toxicology of similar compounds and from animal data. 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 DCE affects health. In one study, animals exposed to 1,1-DCE developed an increased rate of cancer. Although 1,1-DCE has not been shown to cause cancer in humans, a cautious approach considers that 1,1-DCE may cause an increased risk of cancer in humans because of this one suggestive study.
At Carolawn, Phase I and Phase II sampling found 1,1-DCE in both monitoring wells and private residential wells; the highest levels appeared in RW-1 and MW-6. Sampling did not detect 1,1-DCE in soils. Currently, available evidence does not indicate the presence of 1,1-DCE in private well RW-3. As this is the only residential well in use, the ingestion of 1,1-DCE in groundwater is not currently causing health effects.
1,1-DCE is highly volatile. As the maximum detected concentration of 1,1-DCE occurred in private well RW-1, it is reasonable to assume that volatilization of 1,1-DCE from the contaminated groundwater may move through the unsaturated saprolite and enter this residence. As no air sampling from inside this house is available, this pathway cannot be further evaluated at the present time.
The future potable use of well RW-1, the use of another well within the contaminated area, or the unlikely migration of on-site contaminants to well RW-3 could lead to an increased risk of both 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 ATSDR chronic oral MRL in children. Because ATSDR used a safety factors of 1,000 in the derivation of this MRL, the maximum expected dose of 1,1-DCE at the Carolawn site is still below the doses which have caused adverse health effects in animals. It is not certain that these doses would cause health effects in humans. If health effects were to occur, animal studies indicate that the most likely effects would include damage to the liver and kidneys (ATSDR Toxicological Profile for 1,1-Dichloroethene). The presence of other similar compounds, such as trichloroethylene, however, may tend to interact with the toxicity of 1,1-DCE and increase the probability of these effects.
On the basis of Figure 2-2 of the ATSDR Toxicological Profile, a hypothetical adult ingesting maximally contaminated water over a lifetime would incur a moderate increased risk of developing cancer as a result of this exposure. However, carcinogenesis of 1,1-DCE has been observed in only one strain of mice after inhalation of high levels of the compound. The significance of this finding to humans remains debatable.
trans-1,2-DICHLOROETHYLENE
1,2-Dichloroethylene, also called 1,2-DCE, refers to two closely related chemicals: cis-1,2-dichloroethylene and trans-1,2-dichloroethylene. In general, these two chemicals occur together. It is used to make other chemicals and it is used as a solvent.
The inhalation of high levels of 1,2-DCE have caused irritation of the eyes, central nervous system depression, and damage to the liver, kidneys, lungs, and heart. Although air sampling remains unavailable at the Carolawn site, the probable concentrations of this compound are unlikely to cause these effects. As with similar compounds at this site, volatilization from contaminated groundwater with subsequent exposure to the residence RW-1 cannot be evaluated on the basis of current data.
As previous testing of private well RW-3 did not show the presence of 1,2-DCE, RW-3 is the only well currently in use near the site, and superficial soil analyses did not reveal the presence of 1,2-DCE, no health effects are expected from the ingestion of 1,2-DCE at the current time. However, if contaminated groundwater should be used for ingestion, an exposure and the possible development of health effects would occur. The use of RW-1 for a water supply or the installation of another well in the contaminated area could lead to the ingestion of contaminated groundwater, the inhalation of contaminants, and the dermal absorption of contaminants. This would also occur in the unlikely but possible event that contaminated groundwater migrated to the currently used well RW-3.
The chronic ingestion of 1,2-DCE by animals has resulted in a decreased number of red blood cells (anemia). The ingestion of much higher levels has caused central nervous system depression. EPA's Integrated Risk Information System Database (IRIS) cites a 90-day mouse drinking water study. In this study, the male mice showed increases in serum alkaline phosphatase; this may indicate damage to the liver.
The maximum dose of 1,2-DCE is less than the acute and intermediate MRL (ATSDR Toxicological Profile for 1,2-Dichloroethene). However, this dose is greater than EPA's Reference Dose. Therefore, the chronic future consumption and other household uses of contaminated groundwater may lead to an increased incidence of liver damage and anemia. The presence of several closely related compounds at this site may increase the probability of toxicity. These effects, however, would not occur unless contaminated groundwater is used for a household supply.
Trichloroethylene
Trichloroethylene, TCE, is a colorless liquid with an odor similar to chloroform. it is mainly used as a solvent and degreasing agent. Common household products containing TCE include some typewriter correction fluids, paint removers, glues, and spot removers. TCE may also be altered to form other chemicals.
Animal studies indicate that the liver and kidney are the principal targets of oral TCE toxicity. However, the ingestion of groundwater from this site would not contribute a dose large enough to damage these organs (ATSDR Toxicological Profile for Trichloroethylene, Figure 2.4 ).
Also based on animal studies, trichloroethylene may cause an increased incidence of various forms of cancer. Currently, no individuals are ingesting groundwater at the site with the exception of private well RW-3. TCE was not detected in this well in its last sampling. Therefore, there is no current route of exposure indicated. However, the ingestion of contaminated groundwater may be considered as a future possibility. This is possible should extant private well RW-1 be used again as a water source, another potable well be placed within the contaminated area, or the unlikely event that on-site contaminants migrate to the currently used well (RW-3). In these cases, an adult ingesting maximally contaminated groundwater would incur a low to moderate increased risk of developing cancer as a result of this exposure.
Bis-(2-EthylHexyl)Phthalate
Bis-(2-EthylHexyl)Phthalate, a.k.a. Di-EthylHexyl-Phthalate or DEHP, is a liquid used to make plastic more flexible. These plastics are widely used in consumer products such as imitation leather, 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 fluid in electrical capacitors.
According to ATSDR, there are essentially no studies on the health effects of DEHP in humans. In laboratory animals, high doses of DEHP may produce liver damage, produce damage to the male reproductive system, affect reproduction, and produce birth defects. DEHP has been shown to cause an increased incidence of cancer in rats and mice. None of these effects has been documented in humans. Based on an increase in the weights of livers in female guinea pigs, ATSDR has set an oral chronic MRL of 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, no health effects from DEHP are expected at the current time.
Similarly, the incidental ingestion of soils would only expose an individual to insignificantly small doses of DEHP.
However, under worst case conditions, any future ingestion of contaminated groundwater would present a dose which slightly exceeds the MRL for a child. It is therefore possible that the ingestion of DEHP from this site would cause injury to the liver.
Comparing the adult dose to ATSDR's Toxicological Profile for Di(2-EthylHexyl)Phthalate (Figure 2.4), an individual ingestion maximally contaminated groundwater for a lifetime would receive, at most, a low to moderate increased risk of developing cancer as a result of this exposure.
B. Health Outcome Data Evaluation
The State of South Carolina does not currently have an implemented database or registry dealing with health effects in the vicinity of this site. Therefore, no evaluation may be made of health outcome data.
C. Community Health Concerns Evaluation
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 health of the people using this well?
As explained in the above sections, thorough testing of well RW-3 has shown only low levels of chlordane-related compounds. The amount of chlordane is below the EPA MCL; this water could be legally used as a public water source. Additionally, available data do not indicate when this exposure began. Considering the uncertainty in the length of exposure and the small population involved, it appears highly unlikely that ingesting the current concentration of chlordane-related compounds in well RW-3 would result 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 levels unsuitable for human consumption. Well RW-3 has not shown such contamination. Additionally, data from on-site and off-site monitoring wells and regional topography indicate that groundwater flows towards the northeast and southeast of the site. Thus, it appears unlikely that well RW-3 will become contaminated.
However, because of the uncertainties inherent in the local geology, it cannot be absolutely stated that well RW-3 will not become contaminated. Additionally, future projections of chlordane-related compounds in this well cannot be made from available data. Therefore, this recommends the yearly sampling of well RW-3 for VOCs and pesticides.
3. Could fishing and swimming in Fishing Creek lead to health effects?
Sampling of water and sediments for the Remedial Investigation indicate that the Carolawn site has not adversely affected Fishing Creek. However, the site groundwater discharges to Fishing Creek and tributaries lead from the site to Fishing Creek. Future contamination is possible. Therefore, this recommends a regular schedule of sampling of Fishing Creek for VOCs.
4. Will the presence of this site affect the sale of my property?
The reviewers are not qualified to discuss this question.
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