PUBLIC HEALTH ASSESSMENT
PALMETTO WOOD PRESERVING, INC.
CAYCE, LEXINGTON COUNTY, SOUTH CAROLINA
ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
Data in this section are from the 1987 Remedial Investigation report and Feasibility Study. This represents the latest information for this site.
The tables in this section list the contaminants of concern. We evaluate these contaminants in the subsequent sections of the 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:
Contaminants that are listed in the data tables for this section should not be interpreted to mean that they will cause harmful health effects. Rather, the list identifies contaminants that need to be evaluated further in later sections of the public health assessment.
The data tables include the following acronyms:
| CREG | = Cancer Risk Evaluation Guide |
| EMEG | = Environmental Media Evaluation Guide |
| MCLG | = EPA Maximum Contaminant Level Goal |
| MCL | = EPA Maximum Contaminant Level |
| PMCLG | = EPA Proposed MCLG |
| PMCL | = EPA Proposed MCL |
| RfD | = EPA Reference Dose |
| LTHA | = EPA Lifetime Health Advisory |
Contaminants requiring further evaluation are selected by using medium-specific, comparison values. These values include EMEGs, CREGs, and other relevant guidelines. CREGs are estimated contaminant concentrations based on the probability that one additional cancer case may occur in excess of the number that will be expected to occur among one million persons (assuming they have been exposed to the contaminant for 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 at which "no known or anticipated adverse health effect on human health occurs 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 over a lifetime (70 years) at an exposure rate of 2 liters of water per day; however, in deriving these levels the EPA takes into consideration the technical feasibility and economics of water treatment. 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)
TRI is developed by the U.S. Environmental Protection Agency (EPA) from the chemical release information provided by certain industries. The chemical release information is based on contaminants found in air, surface water, groundwater, or soil.
Project staff conducted a search of EPA's Toxic Chemical Release Inventory (TRI) for the years 1988, 1989, and 1990. The search included a 1-mile radius from the plant. As the site was not active in these years, TRI does not provide a listing for this site. TRI did not include any other facilities within a 1-mile radius of the site.
Sampling data from the 1987 RI indicate that soil and groundwater contain elevated levels of arsenic, chromium, and copper. In addition to these metals, a number of organic compounds have been identified at the site.
Soil
The soil samples collected on-site range from 0' to 3' and represent four major areas: (1) the drip shed; (2) the narrow gauge railway; (3) the storage yard; and (4) surface water pond areas near the eastern boundary of the site (Figures 7-1 to 7-4). The highest concentrations of contaminants were found in the drip shed and narrow gauge railways areas. Samples were collected from fifty locations.
Soil analyses showed that the metal concentrations found decreased with depth, with the contamination principally confined to the upper 10 feet of soil. The highest concentrations of contaminants found in subsurface soil samples were associated with the drip shed, narrow gauge, and storage tank areas. Subsurface soil sampling depths for the RI varied from 0 to 27.5 feet.
Arsenic, chromium, and benzo(a)pyrene were detected in on-site soil and found to exceed the comparison values for soil. Contaminants detected in on-site soil are listed in Tables 2 and 3.
Soil remediation on the PWP site is complete. Additional soil samples are needed to better characterize the extent of
contamination found on-site after remediation.
Table 2: Contaminants of Concern -- Concentration in Soil On-site*
| Contaminant | Concentration Range - ppm |
Location Of Maximum Value |
Comparison Value | |
| ppm | Source | |||
| Arsenic | 2.4 - 6200J | NG16 DS02 |
210 | Rfd(Adult) |
| Chromium | ND - 6200 | DS02 | 3500 | Rfd(Adult) |
| Copper | ND - 3600 | DS02 | No Value | |
| Sodium | ND - 960J | NG03 | No Value | |
| Benz(A)Anthracene | ND - 1.2 | NG01 | No Value | |
| Chrysene | 0.045J - 1.2 | NG01 | No Value | |
| Benzo(B and/or K) Fluoranthene |
0.2J - 0.9 | DS02 | No Value | |
| Benzo(a)pyrene | 0.062J - 0.66 | DS02 | 0.12 | CREG |
| Indeno(1,2,3-cd)pyrene | 0.25J - 0.38J | DS02 | No Value | |
| Dibenz(A,H)Anthracene | 0.13J - 0.15J | DS02 | No Value | |
| Benzo(ghi)Perylene | 0.068J - 0.32 | DS02 | No Value | |
| Contaminant | Concentration Range - ppm |
Location of Maximum Value |
Comparison Value | |
| ppm | Source | |||
| Arsenic | ND - 520 | SB17 | 210 | Rfd(Adult) |
| Copper | 3.7 - 620 | SB17 | No Value | |
Groundwater
Samples from six clusters of twelve permanent monitoring wells and twenty-one temporary wells were taken during the RI. Arsenic, chromium, vanadium, and 1,1-dichloroethene were found to exceed the comparison values for groundwater. Iron was also detected in groundwater samples but does not have a comparison value (Figure 10). The RI concluded that the extent of contamination in water is principally confined to the shallow unconfined aquifer.
Groundwater remediation on-site has not been completed. Additional on-site samples are needed to better characterize
the extent of groundwater contamination. As the groundwater remediation is completed, additional samples will be needed
to determine the degree of contamination on the PWP site.
| Contaminant | Concentration Range - ppb |
Location of Maximum Value |
Comparison Value | |
| ppb | Source | |||
| Arsenic | ND - 170J | MW08 | 3 | Rfd(Child) |
| Chromium | 18 - 1,150 | MW12 | 50 | Rfd(Child) |
| Vanadium | 34 - 36 | MW08 | 20 | LTHA |
| Iron | ND - 13,000 | MW04 | No Value | |
| 1,1-Dichloroethene | 1J ** | MW01 | 0.058 | CREG |
Groundwater - Temporary Wells
Twenty-one temporary wells were drilled during the RI (15 were drilled on-site) to evaluate potential contaminant migration in the shallow unconfined aquifer and to determine if contaminants have migrated off-site.
On-site groundwater concentrations of arsenic, chromium, and copper were found to exceed comparison values (Figure 11). Contaminants found in temporary wells are included in Table 5.
Data gaps exist in temporary well samples on-site. Data was not reported for all temporary wells and concentrations
reported indicate that soil contamination of the wells may have resulted. Additional sampling is needed to characterize
the contaminants found in on-site temporary wells.
Table 5: Contaminants of Concern -- Concentration in Temporary Wells On-site*
| Contaminant | Concentration Range - ppb |
Location of Maximum Value |
Comparison Value | |
| ppb | Source | |||
| Arsenic | ND - 1,600 | GW03 GW04 |
3 | Rfd(Child) |
| Chromium | 95 - 110,000 | GW10 | 50 | Rfd(Child) |
| Copper | 24 - 2,000 | GW10 | 1,300 | MCL |
| Sodium | 3,500 - 160,000 | GW05 | No Value | |
Air
The investigative team for the RI used air monitoring equipment prior to the site visit, and during the initial site visit. During the RI, the air was continuously monitored. Results of air monitoring on-site indicated no readings of organic vapors that exceeded action levels.
The on-site soil remediation has been completed, making the possibility of soil becoming airborne and resulting in air contamination very unlikely. However, if the area should become further developed, additional monitoring should to be conducted and this conclusion may change.
Soil
No surface soil data exist for this site. Surface soil is defined by ATSDR to be from 0" - 3" of soil.
During the RI, soil samples were taken and analyzed to characterize the type and extent of vertical soil contamination. A total of twenty-one boreholes were drilled at/or near the site. The soil boring sampling locations were in the main process/narrow gauge railway and drip shed areas (Figure 8).
Two laboratories collected samples to evaluate migration patterns of contaminants from the PWP site; one an on-site laboratory, the other a contracted laboratory. The on-site laboratory analyzed soil samples for chromium, copper, and PCP. The contracted laboratory detected arsenic and benzo(a)pyrene at levels exceeding comparison values. Table 6 lists contaminants of concern for soil off-site.
Subsurface soil samples were taken in the same manner as on-site subsurface soil samples. Arsenic and chromium were detected at levels that exceeded the comparison values. Copper, which has no comparison value, was also detected. Table 7 presents contaminants of concern found in subsurface soil samples.
The on-site soil remediation has been completed; however, we have no current data to evaluate contaminant levels found
on-site or off-site. When this data becomes available, we may better evaluate the current concentrations of contaminants
found. Surface soil samples (ATSDR definition - 0 - 3") are needed to better characterize the extent of contamination and
to better determine the possibility for exposures to surface soil by local residents.
Table 6: Contaminants of Concern - Concentration in Soil Off-site*
| Contaminant | Concentration Range - ppm |
Location of Maximum Value |
Comparison Value | |
| ppm | Source | |||
| Arsenic | 3.6 - 32 | NG15 | 15 | Rfd(Child) |
| Benz(A)Anthracene | 0.087J - 0.18J | SWP11 | No Value | |
| Chrysene | 0.19J - 0.3J | SWP11 | No Value | |
| Benzo(B and/or K) Fluoranthene |
0.21J - 0.31J | SWP11 | No Value | |
| Benzo(a)pyrene | 0.16J | SWP10 SWP1 |
0.12 | CREG |
| Lead | 1 - 280 | SWP07 | No Value | |
| Dibenz(A,H)Anthracene | 0.15J - 0.15J | SWP07 | No Value | |
Table 7: Contaminants of Concern - Concentration in Subsurface Soil Off-site*
| Contaminant | Concentration Range - ppm |
Location of Maximum Value |
Comparison Value | |
| ppm | Source | |||
| Arsenic | ND - 970 | SB10 | 15 | Rfd(Child) |
| Chromium | 4 - 1400 | SB09 | 250 | Rfd(Child) |
| Copper | 3.7 - 1100 | SB10 | No Value | |
Groundwater
Samples from six clusters of twelve monitoring wells and twenty-one temporary wells were taken during the RI. Chromium, copper, and vanadium concentrations exceeded comparison values. Iron, which has no comparison value, was also detected in off-site groundwater. Table 8 presents the contaminants of concern found in groundwater off-site.
Site topography shows three water drainage patterns and the groundwater flow through the PWP site (Figure 6). Additional monitoring wells are needed to better ascertain the extent of contaminant migration from the site.
Three of the four contaminants of concern were detected in one sample cluster. This sample cluster is on the same
property but at different locations and varying depths (Figure 10). These samples give an accurate reading of contaminant
migration from the site to that area; however, the property has been abandoned and more sampling locations and additional
data are needed to determine contaminant migration to the southwest and southeast of the site.
Table 8: Contaminants of Concern - Concentration in Groundwater Off-site*
| Contaminant | Concentration Range - ppb |
Location of Maximum Value |
Comparison Value | |
| ppb | Source | |||
| Chromium | 13 - 7,800 | MW10 | 50 | Rfd(Child) |
| Copper | ND - 2,700 | MW16 | 1300 | MCL |
| Vanadium | ND - 79 | MW04 | 20 | LTHA |
| Iron | 400 - 24,000 | MW04 | No Value | |
Groundwater - Temporary Wells
Temporary wells were drilled to evaluate potential contaminant migration in the shallow unconfined aquifer and to determine if contaminants have migrated off-site.
Arsenic, nickel, lead, vanadium, and manganese concentrations exceeded comparison values. Several other contaminants, see Table 9, were also detected but no comparison values were available.
Data reported for off-site temporary wells included only one temporary well and cannot be considered an adequate
representation of migration from the site; therefore, a significant data gap exists in assessing the site's public health
implications. Additional sampling of off-site temporary wells is needed to better characterize the extent of contaminant
migration.
Table 9: Contaminants of Concern -- Concentration in Temporary Wells Off-site*
| Contaminant | Concentration Range - ppb |
Location of Maximum Value |
Comparison Value | |
| ppb | Source | |||
| Arsenic | 2,200 ** | GW08 | 3 | Rfd(Child) |
| Nickel | 200 ** | GW08 | 100 | LTHA |
| Lead | 270 ** | GW08 | 50 | MCL |
| Vanadium | 890 ** | GW08 | 20 | LTHA |
| Manganese | 2,600 ** | GW08 | 1,000 | Rfd(Child) |
| Iron | 320,000 ** | GW08 | No Value | |
| Sodium | 23,000 ** | GW08 | No Value | |
Groundwater - Private Wells
Nine private wells were sampled in the vicinity of the PWP site to indicate the extent of contaminant migration via groundwater and to assess potential health hazards to neighboring residents (Figure 5).
Only one well (PW01) showed contamination by chromium in excess of comparison values (Table 10). PW01 is located southeast of the site and is no longer used. When contamination was detected, the homeowners were supplied with well water and later with municipal water.
Groundwater remediation for the PWP site is not complete and current private well sampling is needed to characterize the
extent of contaminant migration from the site to local residential wells.
Table 10: Contaminants of Concern -- Concentration in Private Wells Off-site*
| Contaminant | Concentration Range - ppb |
Location of Maximum Value |
Comparison Value | |
| ppb | Source | |||
| Chromium | ND - 8,600 | PW01 | 50 | Rfd(Child) |
Surface Water and Sediment
Surface water and sediment samples were collected to investigate the possibility that surface water runoff represents a migratory pathway for contaminant movement off-site. Areas sampled consisted of a discharge point at the pond located approximately 150 feet southwest of the site, a swampy area located approximately 3,000 feet northeast of the site, a drainage area approximately 1,500 feet southeast of the site, an unnamed creek exiting the swampy area located approximately 7,000 feet east of the site, and a discharge feature from the swampy area approximately 6,000 feet northeast of the site (Figure 9).
Surface water samples were collected in compliance with EPA protocol. Samples were analyzed for extractable (semivolatiles - compounds which do not readily evaporate) and volatile organic compounds (VOCs), pesticides, metals, and cyanide. Surface water samples detected arsenic, vanadium, manganese, and bis(2-ethylhexyl)phthalate at levels that exceed the comparison values. Table 11 presents contaminants of concern for surface water.
Sediment sampling detected arsenic at a level that exceeded the comparison value. No organic compounds were detected in these samples. At this time, there are no plans to remediate surface water and sediments. Table 12 presents contaminants of concern for sediment.
More current sampling data and more sampling locations are needed to determine the extent of contamination in these media.
Table 11: Contaminants of Concern -- Concentration in Surface Water Off-site*
| Contaminant | Concentration Range - ppb |
Location of Maximum Values |
Comparison Value | |
| ppb | Source | |||
| Arsenic | ND - 78 | SW01 | 3 | Rfd(Child) |
| Vanadium | ND - 36 | SW02 | 20 | LTHA |
| Manganese | 180 - 8,200 | SW04 | 1000 | Rfd(Child) |
| Iron | 1100 - 77,000 | SW01 | No Value | |
| Sodium | 3100 - 16,000 | SW03 | No Value | |
| Bis(2-Ethylhexyl) Phthalate |
ND - 5,500 | SW02 | 2.5 | CREG |
Table 12: Contaminants of Concern -- Concentration in Sediment Off-site*
| Contaminant | Concentration Range - ppm |
Location of Maximum Value |
Comparison Value | |
| ppm | Source | |||
| Arsenic | ND - 33 | SD01 | 15 | Rfd(Child) |
Air
The investigative team for the RI used air monitoring equipment during the initial site visit and throughout the remedial investigation. Results of the monitoring off-site indicated no readings of organic vapors above EPA action levels. However, should the area be further developed the air should be monitored again to confirm these conclusions.
C. Quality Assurance and Quality Control (QA/QC)
The data in this section are from the 1987 Remedial Investigation/Feasibility Study. Thus, this report contains the latest data for this site. Quality Control and Quality Assurance conclusions drawn for this public health assessment are determined by the validity of the analysis and conclusions made and the availability and reliability of the referenced information. SCDHEC assumes that adequate quality assurance and quality control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting.
Analyses of different media for chromium obtained data on only total chromium. Therefore, no analytical information exists on the state/form of chromium in the sampled media. In this public health assessment, we have assumed that chromium in the environment exists in the Chromium VI state.
At the end of each medium discussion in the preceding subsections of On-site and Off-site Contamination, we have explained whether the information is sufficient to make an assessment of the levels of contaminants to which persons are or might be exposed. Overall, the data appears to be reliable; however, data reported for temporary wells, both on-site and off-site, do not present reliable information and will not be evaluated further in this public health assessment.
The site is secured by an 8-foot high chain-link fence with barb wire on top and evidence does not indicate trespassing
has occurred or will occur in the future. There are high weeds and an abandoned old truck in the southwestern border of
the site. There are several wood piles on the former manufacturing company located next to the site. These conditions
potentially present a physical hazard to anyone who may wander into the area.
To determine whether nearby residents are exposed to contaminants migrating from the site, SCDHEC evaluates the environmental and human components that lead to human exposure. Pathway analyses consist of the following five elements: a source of contamination, transport through an environmental media, a point of exposure, a route of human exposure, and ultimately the exposed population.
SCDHEC identifies exposure pathways as completed, potential, or eliminated. Completed pathways are those that meet the five elements listed above. Potential pathways indicate that exposure to a contaminant may have occurred, may be occurring, or may occur in the future. A potential pathway exists when one of the above listed five elements is missing, but could exist. An eliminated pathway occurs when at least one of the five elements is missing and will never be present.
A. Completed Exposure Pathways
Groundwater
Past, current, and future exposure pathways may result from contamination of groundwater at several points of exposure: residential wells, undeveloped areas, and the site. While several points of exposure could occur in the future, we believe that only residential wells and undeveloped areas represent likely points of exposure.
The RI sampling data show that contaminants have migrated off the PWP site. Contaminants exceeding the comparison values were detected in off-site monitoring wells and one private drinking well (PW01). PW01 (Figure 5) is located southeast of the site. A past exposure pathway exists for people who used PW01 by ingestion of groundwater and dermal contact. The owner of PW01 was advised to discontinue use of the well. No data are available from the past to evaluate length of exposure or health effects to people who used PW01; however, sampling conducted during the RI detected chromium levels in excess of the comparison values and municipal water was made available to this resident.
We believe contamination of this well may have occurred due to the site topography and drainage patterns for this site (Figure 6). There are three major drainage pathways for the site. The PWP site slopes from the northwest toward several residences located to the southeast of the site. A small swamp is located approximately 300 feet from the southwest corner of the site, across South Carolina Road 129. This pond discharges into a small drainage area located approximately 250 feet south of the property boundary of the adjacent manufacturing site.
B. Potential Exposure Pathways
Table 13: Potential Exposure Pathways
| Exposure Pathway Elements | Time | ||||
| Source | Environmental Medium |
Point of Exposure |
Route of Exposure |
Exposed Population |
|
| PWP | Soil | Off-Site | Ingestion Dermal Contact |
Children Adults Workers |
Past Present Future |
| PWP | Groundwater | On-Site Off-Site |
Ingestion Dermal Contact |
Children Adults Workers |
Past Present Future |
| PWP | Surface Water and Sediment |
Off-Site | Ingestion Dermal Contact |
Children Adults Workers |
Past Present Future |
| PWP | Air | On-Site Off-Site |
Inhalation | Children Adults Workers |
Past Future |
Soil
In the past, exposure to contaminants at the PWP site could have occurred prior to the removal of the contaminated soil, and prior to the site being secured by an 8-foot high chain-link fence. This past exposure could have happened to anyone who wandered onto, worked on, or to children who played on the site. The routes of exposure could have occurred through dermal contact, ingestion of soil, or inhalation of soil particles. However, because soils were not sampled prior to the site closing and because the area is sparsely populated, this past exposure pathway cannot be evaluated in this public health assessment.
The results of on-site soil sampling conducted in 1986 indicated several metals and extractable semivolatile organic compounds. In 1989, approximately 12,685 cubic yards of contaminated soil were excavated, treated, solidified, and placed under a concrete pad to eliminate off-site contaminant migration.
The on-site soil remediation has been completed; however, we have no data to evaluate contaminant levels currently found on-site or to evaluate off-site contaminant migration. Therefore, this pathway will be considered a potential pathway in this public health assessment.
Off-site sampling conducted during the RI showed contaminants in the southern corner of the site. Residents may be exposed to contaminants from the PWP site through dermal contact, ingestion of soil, or inhalation of soil particles. When additional data becomes available, we may better evaluate the concentrations of contaminants found and determine the degree of off-site migration.
Soil surveys produced by the United States Department of Agriculture, Soil Conservation Service (SCS, 1976) indicates two types of surface soil in the area of the PWP site. These are the Lakeland soils and Pelion loamy sand. In a representative profile, the surface layer is very dark gray sand approximately three inches thick. This material is underlain to a depth of 90 approximate inches and is sandy. Runoff is slow but permeability is rapid with a very low available water capacity. The pelion loamy sand is typically sandy loam underlying a stratified sand or clay subsoil which extends to a depth of up to 40 inches. Runoff is moderate on this soil and in places bonds briefly after rains. Permeability is moderate in the upper soils and slow in the deeper soils (LETCO, 1983). Based on this information and due to the vegetative cover on the site, the possibility for soil contamination to migrate extensively off-site is not likely.
Groundwater
Past, current, and future exposure pathways may result from contamination of groundwater from private drinking wells. Contamination was detected in PW01 prior to the RI; however, no data are available as to length of exposure prior to sampling of this well. No contamination was found that exceeded the comparison values in other private wells sampled during the RI; therefore, no health effects were predicted for well users at that time.
One home in the southeastern border of the site showed chromium contamination that exceeded the comparison values in 1982. At that time, this home was supplied with well water, and municipal water was made available to this area. The home has since been abandoned and there is a possibility that the new owners may utilize private wells in the future.
Other residents in the area are still utilizing private wells as the source for drinking, bathing, and cooking. Groundwater remediation is not complete on this site and the site topography and water drainage patterns reflect the possibility that migration of contaminants could extend to local residential wells affected by groundwater flow.
Since we have no current sampling data for residential wells, we cannot assume that contaminants have migrated to these wells. Because PW01 showed contamination exceeding the comparison value, groundwater at this location represents a potential future exposure pathway to residents through ingestion of water or from dermal contact.
Access to the site is restricted to the public; therefore, no exposures to contaminants are known to be occurring from on-site sources. The levels of contaminants found on-site during the RI were not considered to be of concern; however, current sampling data need to be evaluated to determine on-site contaminant levels. On-site workers may be exposed to groundwater contamination through ingestion or dermal contact.
As a groundwater treatment plant is being constructed to remediate the groundwater contamination on the site, we do not foresee this to be a pathway of concern.
Surface Water/Sediments
The surface water and sediment sampling performed during the RI indicated contaminants of concern. Samples were collected to investigate the possibility that surface water runoff represents a migratory pathway for contaminant movement off-site. Samples taken to determine stream flow in the vicinity of the site are monitored at three locations: the Congaree River, Gills Creek, and Big Beaver Creek.
Surface water runoff from the site drains to the Congaree River, which is one of the major tributary rivers in the Santee-Cooper River Basin. Drainage to the Congaree River occurs by two major routes, Dry Creek and Congaree Creek, which flow northeastwardly and southeastwardly from the site to the Congaree River, respectively. The Congaree River is formed by the confluence of the Saluda and Broad Rivers near northeast Columbia. Much of the Congaree river and lower portions of its tributary streams blend with swampland.
Stream flow on the Congaree River is affected by regulated discharges from hydroelectric power plants on the Saluda and Broad Rivers and several flood control and recreational impoundments along Gills Creek. Except for occasional water quality problems, physical, chemical, and biological water quality data indicate that current conditions in the main stem river are generally good. Upstream and downstream samples from this River are needed to better ascertain contaminant migration from the PWP site.
If additional sampling shows contamination, there is a potential for exposure via ingestion or dermal contact with contaminants; however, this route of exposure is considered unlikely. Available data are not adequate to estimate any future concentrations or exposures.
Air
Air monitoring conducted during the RI for the PWP site indicated no readings of contaminants above action levels. At this time, the RI concludes that exposure to contaminants transported in air is not likely. Therefore, this pathway will not be evaluated further.
This pathway may be of concern in the future if contaminants from the PWP site become airborne. At that time, air on
the site may serve as a vehicle for contamination and allow workers on-site to inhale contaminants or transport
contaminants off-site where they may be inhaled by local residents.
In this section we will discuss the health effects in persons exposed to specific contaminants. To evaluate health effects, ATSDR has developed Minimal Risk Levels (MRL) for contaminants commonly found at hazardous waste sites. The MRL is an estimate of daily human exposure to a contaminant below which non-cancer, adverse health effects are unlikely to occur. MRLs are developed for each route of exposure and for the length of exposure.
When a MRL is not available, ATSDR refers to EPA's Reference Dose (RfD). The RfD is an estimate of daily human exposure to a contaminant for a lifetime below which (non-cancer) health effects are unlikely to occur.
The calculated doses are estimations of the amount of chemicals a person can be exposed to. The computations are based on the assumptions 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, and a child drinks half that amount. Adults typically ingest 50 to 100 milligrams of soil per day (mg/day) by inhalation of small soil particles carried in the air, and by placing soiled hands and other objects in the mouth. We assume that small children ingest a greater amount of soil, typically 200 mg/day, because they generally tend to place objects in their mouths.
These assumptions and the respective exposure scenarios are used to determine the estimated doses for each chemical. The estimated doses will be compared to health guidelines and the available scientific literature to determine if health effects are likely to occur.
Arsenic
Arsenic is a naturally-occurring element in the earth's crust. Pure arsenic is a gray metal-like material, but this form is not common in the environment. Arsenic is usually found combined with other elements. Most arsenic compounds are white or colorless powders that do not evaporate. They have no smell, and most have no special taste. Thus, you usually cannot tell if arsenic is present in food, water, or air (ATSDR 1989a).
The main use of arsenic in the United States is as a preservative for wood to make it resistant to rotting and decay. It is also used in different types of pesticides like insect killers and weed killers. The use of arsenic as a pesticide has contributed to elevated levels of arsenic in several areas within the southeastern United States (ATSDR 1989a).
Arsenic was not detected in off-site private wells and no completed exposure pathway currently exists for arsenic. However, if potential exposure pathways become completed pathways, people could be exposed to arsenic by ingestion of or dermal contact with contaminated soil or surface water. In the future, arsenic migration in groundwater and/or the installation of new private wells may lead to exposure and adverse health effects associated with arsenic.
ATSDR has not established an MRL for arsenic; however, EPA has established a reference dose of 0.0003 mg/kg/day. The following discussion on possible health effects is based on a comparison of site related doses to the EPA reference dose.
Ingestion of arsenic over many years (typically 10 years or more) may lead to irritation of the gastrointestinal tract, including nausea, vomiting, diarrhea, and abdominal pain. Other effects may include a decreased production of red and white blood cells, abnormal heart function, blood-vessel damage, and impaired nerve function causing a "pins and needles" sensation in hands and feet. The single most characteristic effect of long-term oral exposure to inorganic arsenic is a pattern of skin changes including the darkening of the skin and the appearance of small "corns" or "warts" on the palms, soles, and torso (ATSDR 1989a).
Direct skin contact with arsenic compounds may cause the skin to become irritated with some redness and swelling. However, it does not appear that skin contact with arsenic is likely to lead to any serious internal effects.
Exposure to arsenic is not anticipated to result in acute (immediate) health effects at the PWP site.
Bis(2-Ethylhexyl)Phthalate
Bis(2-Ethylhexyl)Phthalate, also known as Di(2-Ethylhexyl)Phthalate or DEHP, is a liquid used to make plastic more flexible. These plastics are used in a variety of consumer products such as imitation leather, rainwear, footwear, upholstery, flooring, tablecloths, shower curtains, food packaging materials, and children's toys. It is also used as a hydraulic fluid and as a dielectric fluid in electrical capacitors (ATSDR A989d).
DEHP was not detected in private wells and no completed exposure pathway for DEHP currently exists. However, if potential exposure pathways become completed pathways, people could be exposed to DEHP by ingestion of or dermal contact with contaminated surface water from a swamp area northeast of the site.
The EPA reference dose for DEHP is 0.02 mg/kg/day. Most of what is known about the health effects of DEHP comes from animal studies, especially studies in rats and mice. Because DEHP appears to affect rats and mice differently than it affects humans and other animals, it is difficult to predict health effects in humans using information from animal studies.
DEHP is classified by the EPA as a probable human carcinogen. A probable human carcinogen is a chemical for which there is sufficient evidence of carcinogenicity in animals, but inadequate evidence or no data from human epidemiologic studies. DEHP has also been shown to cause an increased incidence of cancer in rats and mice. Exposure to the levels of DEHP related to the PWP site represent an "insignificant risk" of cancer.
While human studies are not available, laboratory animals exposed to high doses of DEHP have experienced liver damage and male reproductive system damage. Reproduction in these animals was affected and birth defects were more likely. However, none of these effects have been documented in humans. Human absorption of DEHP in the body is different from that of rodents (ATSDR 1989d). Therefore, many of the effects seen in animals after exposures to DEHP may not occur in humans.
Chromium
Chromium is a naturally occurring element which is found in three different states: chromium 0, chromium III (trivalent chromium), and chromium VI (hexavalent chromium). Chromium is used to make steel and other alloys, bricks for metallurgical furnaces, for chrome plating, in the manufacture of pigments, for leather tanning, wood treatment, and water treatment for industrial applications (ATSDR 1989b).
Chromium was detected in one off-site private well (PW01) and a past completed exposure pathway exists for chromium. In addition, potential exposure pathways may also become completed pathways with people becoming exposed to chromium by ingestion of or dermal contact with contaminated groundwater or soil. In the future, chromium migration in groundwater and/or the installation of new private wells may lead to exposure and adverse health effects associated with chromium.
Sampling has not determined if chromium is present in the trivalent (chromium III) or hexavalent state (chromium VI) at the PWP site although hexavalent chromium is used in the wood preserving process.
Chromium VI has an EPA chronic reference dose of 0.005 mg/kg/day and Chromium III has an EPA chronic reference dose of 1 mg/kg/day; however, potential exposure doses estimated for all media at the PWP site did not exceed the reference dose for chromium III. However, since chromium VI may be reduced to chromium III, possible health effects from chromium III exposure will be mentioned as well.
Health effects associated with ingestion of or dermal contact with chromium VI contaminated water from private well PW01 over many years may lead to the enhancement of dermatitis. Dermal contact with water from this well may cause reddening of the skin. Other health effects that may occur from exposure to chromium at these levels have not been well characterized. Recent evidence has suggested that exposure to chromium III may caused decreased spermatogenesis in mice; however, this has not been shown to occur in humans (ATSDR 1989b).
A potential soil pathway for chromium was also identified. Long-term ingestion of contaminated soil may result in the enhancement of dermatitis. However, it is not likely that a person would ingest the amount of soil necessary to result in adverse health effects.
Copper
Copper occurs naturally in rock, soil, water, sediment, and air. The U.S. penny, electrical wiring, and some water pipes are made with copper (ATSDR 1990f).
Potential exposure pathways were identified for copper. Exposure to copper may occur in the future through the ingestion of or dermal contact with contaminated groundwater or soil; however, no current exposures to copper are known to have occurred or to be occurring.
Copper is necessary for good health; it is an essential element for all living organisms, including man. However, the estimated dose a person would receive from the levels of copper associated with the PWP site exceed the lowest observed adverse effect level (LOAEL) of 0.056 mg/kg/day. Therefore, ingestion of maximally contaminated soil or groundwater may cause vomiting, diarrhea, stomach cramps, and nausea.
Studies have shown that some individuals may show signs of allergic contact dermatitis from skin contact with materials containing copper. However, neither the dose nor the duration of exposure necessary to produce this effect was available (ATSDR 1990f).
1,1-Dichloroethene
1,1-Dichloroethene (DCE) is a chemical used to make certain plastics such as packaging materials and flame-retardant fabrics. It is a clear, colorless liquid that evaporates quickly at room temperature and has a mild, sweet smell like chloroform (ATSDR 1989c).
Potential exposure pathways were identified for DCE. Exposure to DCE may occur in the future through the ingestion of or dermal contact with private well water if it becomes contaminated; however, no current exposures to DCE are known to have occurred or to be occurring.
Limited information is available regarding the systemic effects of human exposure to DCE. High amounts of DCE in animal studies have caused liver, kidney, heart, and lung damage and have also caused nervous system disorders and death after short exposures. The amount of damage depends on the level of exposure and the length of time exposed. However, the oral dose from exposure to DCE in groundwater on the PWP site is not expected to result in adverse systemic health effects.
No studies were located regarding health effects in humans or animals following dermal exposure to DCE.
DCE is classified as a possible human carcinogen. A possible human carcinogen is a category for which there is limited evidence from animal studies and no human studies. The oral dose from exposure to DCE on-site is expected to cause no apparent increased cancer risk.
Iron
Iron is an essential metal in the human diet. The Recommended Daily Allowance for iron in the diet is 10-18 mg/day. However, excess iron in the diet may result in adverse health effects. Ingestion of large doses of iron may cause vomiting, liver damage, and renal failure. Excessive iron in the diet over time may lead to the accumulation of iron in the liver, disturbance of liver function, and even cardiovascular effects (Klaassen 1986).
Potential exposure pathways were identified for iron. Exposure to iron may occur in the future through the ingestion of or dermal contact with contaminated groundwater or surface water; however, no current exposures to DCE are known to have occurred or to be occurring.
Some individuals may be genetically sensitive to iron (e.g. Wilson's disease). Individuals should consult with their physician before ingesting water containing high levels of iron.
The levels of iron in water associated with the PWP site may make the water taste bad should exposure to iron occur in the future; however, the levels of iron in groundwater do not exceed the Recommended Daily Allowance and no adverse health effects are expected.
Lead
Lead is a naturally-occurring element which may be found in most environmental media. It has a wide range of uses including storage batteries (automobile batteries), solders, pipes, various chemicals, and gasoline additives (ATSDR 1990d).
Potential exposure pathways were identified for lead. Exposure to lead may occur in the future through the ingestion of or dermal contact with soil; however, no current exposures to lead are known to have occurred or to be occurring.
Although lead may cause both acute and chronic effects, major concern has focused on the neurotoxicity of lead in children which may manifest itself as learning disorders. Lead toxicity in adults may contribute to hypertension, particularly in middle-aged males (ATSDR 1990d).
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 carcinogenic potency of lead.
Manganese
Manganese is a naturally-occurring element. Small amounts of manganese are an essential part of the human diet. Some manganese compounds are used in the production of batteries, and as a component of some ceramics, pesticides, fertilizers, and nutritional supplements (ATSDR 1990a).
Potential exposure pathways were identified for manganese. Exposure to manganese may occur in the future through the ingestion of or dermal contact with surface water; however, no current exposures to manganese are known to have occurred or to be occurring.
The EPA reference dose for manganese is 0.1 mg/kg/day for chronic (a year or more) exposure. A child's estimated oral dose for manganese in surface water monitored near the PWP site is higher than the reference dose. However, adverse health effects in humans who ingest higher than normal amounts of manganese are not well characterized. Some data suggest that ingestion of higher than normal amounts of manganese may have limited neurological effects (ATSDR 1990a). This data is not conclusive and other factors may be necessary for the effects to occur.
No studies were located regarding health effects resulting from skin exposure to manganese.
Polycyclic Aromatic Hydrocarbons (PAHs) - Carcinogenic
Polycyclic aromatic hydrocarbons are a group of chemicals that are formed during the incomplete burning of coal, oil and gas, garbage, or other organic substances. PAHs can be man-made or occur naturally. PAHs are found throughout the environment and are used in medicines and to make dyes, plastics, and pesticides. Benzo(a)anthracene, benzo(b and/or k) fluoranthene, benzo(ghi)perylene, benzo(a)pyrene, chrysene, and indeno(1,2,3-cd)pyrene are PAHs detected at the Palmetto Wood Preserving site (ATSDR 1990e).
Potential exposure pathways were identified for PAHs. Exposure to PAHs may occur in the future through the ingestion of or dermal contact with soil; however, no current exposures to PAHs are known to have occurred or to be occurring.
In evaluating the potential human carcinogenicity of chemicals, EPA uses the approach given in "Guidelines for Carcinogenic Risk Assessment" (51 FR 33992, September 24, 1986). The EPA has classified PAHs as probable human carcinogens. Probable human carcinogens are chemicals for which there is sufficient evidence of carcinogenicity in animals, but inadequate evidence or no data from human epidemiologic studies.
Laboratory animals that ingest PAHs have developed tumors. These animals also developed tumors after PAHs were applied to their skin or after they had inhaled them over a long period of time. Reports in humans show that individuals exposed by breathing or skin contact for a long period of time to mixtures of other compounds and PAHs can also develop cancer (ATSDR 1990e).
Mice fed high levels of benzo(a)pyrene during pregnancy had difficulty reproducing and so did their offspring. Birth defects were also more likely to occur. While similar effects may be seen in humans, no evidence is available to support this assumption (ATSDR 1990e).
An estimate of the carcinogenic potency of PAHs is under review; this public health assessment will be updated when this information becomes available.
Sodium
Sodium is a component of table salt (sodium chloride). Is also found in salt water. Evidence indicates that an increased intake of sodium may worsen high blood pressure in some sensitive individuals. Additionally, people taking some medicines may need to limit their intake of sodium.
Potential soil and surface water pathways were identified for sodium. However, no reliable evidence suggests that people working on or living near the site are currently exposed to excess sodium.
Vanadium
Vanadium is a white to gray metal and is a natural element in the earth. Vanadium is also found naturally in fuel oils and coal. These compounds are used in the making of steel, rubber, plastics, ceramics, and certain other chemicals.
Potential exposure pathways were identified for vanadium. Exposure to vanadium may occur in the future through the ingestion of or dermal contact with contaminated groundwater or surface water; however, no current exposures to DCE are known to have occurred or to be occurring.
The ATSDR MRL for vanadium is 0.003 mg/kg/day. The oral dose for vanadium in groundwater and surface water on or near the PWP site slightly exceeds the MRL. Animals studies have shown various adverse health effects after consuming high levels vanadium in water. For example, rats who ingested water with 4000 ppb of vanadium in it for 3 months had minor changes in the cells in their kidneys and lungs. However, the dose that these rats received is much greater than humans would receive from vanadium at the PWP site; therefore, adverse health effects from oral exposure to vanadium at levels associated with the PWP site are not expected.
B. Health Outcome Data Evaluation
As no health outcome data exists for the Palmetto Wood Preserving site, there is no further discussion at this time.
C. Community Health Concerns Evaluation
The first concern expressed about this site was possible drinking water contamination of PW-01 in 1983 (Figure 5). The well was tested and showed high levels of chromium and the owner was advised to discontinue use of the well. Water was provided for this household and it utilized municipal water. All private wells within the vicinity of the site were tested at that time and contamination was not found. Since these wells showed no contaminants, they were not considered to be a health risk.
As the site has been closed since 1985 and site access is restricted by an 8-foot high chain-link fence, there are no known exposures to contaminants on-site. Municipal water is now available to local residents; however, residents in the southeastern corner of the site are still utilizing private wells. Conversations with these residents during the 1992 site visit indicated the citizens are still concerned about groundwater contamination. We cannot address this issue at this time because of lack of recent sampling data.
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