PUBLIC HEALTH ASSESSMENT
KALAMA SPECIALTY
BURTON, BEAUFORT COUNTY, SOUTH CAROLINA
ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
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:
In the data tables that follow under the On-site Contamination and the Off-site Contamination subsections, the listed contaminant does not mean that it will cause adverse health effects from exposures. Instead, the list indicates which contaminants will be evaluated further in this Public Health Assessment.
The data tables include the following acronyms:
| CREG | = | Cancer Risk Evaluation Guide |
|
EMEG |
= | Environmental Media Evaluation Guide |
| RMEG | = | Reference Dose 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 |
Comparison values for health assessment are contaminant concentrations in specific media that are used to select contaminants form further evaluation. These values include EMEGs, CREGs, and other relevant guidelines. CREGs are estimated contaminant concentrations based on 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 effect on the health of persons should occur which allows an adequate margin of safety. PMCLGs are MCLGs that are being proposed. MCLs represent contaminant concentration 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 liter 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.
In gathering environmental monitoring information for the Remedial Investigation, PBS&J collected environmental samples from soil, surface water, sediment and groundwater (Figures 4, 5 and 6). Soil samples were collected only in on-site locations during sampling events in July 1989, March 1990 and September to October 1991. Groundwater samples were obtained in on-site and off-site areas during four sampling rounds: October 1989, December 1989, February 1990 and October 1991. In the same four sampling rounds plus another sampling event in November 1991, surface water and sediment samples were collected from the L-shaped ditch at both on-site and off-site portions. All samples were analyzed for organic and inorganic compounds (12).
Groundwater samples were obtained from monitoring wells, local residential wells and industrial wells. Monitoring wells were installed within the water table aquifer (designated as MW wells) and the limestone aquifer at a depth of approximate 100 feet (LW wells). Water table wells were completed at several depths: approximate 10, 25, 30, 40, 60 and 80 feet. Monitoring wells can be constructed as a single well or a well cluster. A well cluster contains more than one well. At KSCI as seen in the Figure 6, a well cluster contains 2 or 3 wells and is designated as, for instance, MW-46,A,B, with MW-46 be the deepest well and MW-46B the shallowest well. Based on groundwater flow patterns, historical sampling results and potential contamination source areas, PBS&J selected, with consent of the EPA and SCDHEC, 53 monitoring wells, 3 industrial wells (CW, CW-DRINK and CW-PROD) and 3 local wells (GR, MAS and MASL) to obtain groundwater samples during the Remedial Investigation (Figure 6) (12).
Toxic Chemical Release Inventory (TRI)
Project staff searched the Toxic Chemical Release Inventory (TRI) data within a 1-mile radius of KSCI using geographic coordinates and area zip codes.
TRI is a database managed by the EPA since 1987. The inventory contains information on the annual estimated releases of over 300 toxic chemicals into the environment (air, water and land) by industry.
Mandated by federal regulations, Title III of the Superfund Amendments and Reauthorization Act (SARA) of 1986, facilities with 10 or more full-time employees are required to report to the EPA on releases of any of those 300 toxic chemicals during their business activities. Based on these reports, a database has been established and is updated annually. The database records the names and addresses of facilities which manufacture, process, or use these toxic chemicals, and amounts released to environment or transferred to waste sites.
The TRI search reported no releases of toxic substances by operating facilities in the KSCI area. However, the TRI database does not completely cover all toxic substances used in this area, especially those used by some companies that terminated their operations before the existence of the TRI program, such as KSCI. Table 2 (Appendix B) shows the raw materials and products handled at the site from 1976-1983.
Air
No ambient air samples were taken in the on-site area.
Soil
Two common methods can be employed to obtain a soil sample: discrete or composite method. In the discrete method, a sample is obtained from a single depth at one location. While a composite sample is a mixture of several samples collected either from several different depths at a single location (depth-composition), from the same depth at multi-locations (location-composition), or from multi-depths at different locations (full-composition). These methods were used to collect soil samples during the RI at KSCI.
85 soil samples were collected in four sampling rounds during the RI. Seventeen of the 85 samples were obtained from the depth interval of 0 to 12 inches with depth-composition method. Another 26 location-composition samples were collected from grid A at depths of 1 and 3 feet, and from each grid of grids B through I at depths of 1, 3 and 5 feet (Figures 4 and 5). The remainder are discrete samples collected from subsurface approximately 1 and 6 feet below the ground surface (12). No soil samples were taken from the depth of 0-3 inches. ATSDR defines surface soil as 0-3 inches since persons are most likely to be exposed to soil at that depth.
Shallow subsurface soils in the area immediately west of the operator pad and north of the tile field (B5A, grids A and B, Figure 4) contained the highest contamination with several organic compounds including benzene, 1,2-dichloroethane, ethylbenzene and methylene chloride. Elevated levels of lead and mercury were also detected in the vicinity of the operations area (Table 3, Appendix B). Soil samples from various areas across the site detected less compounds and lower concentrations (12).
In general, concentrations of organic compounds detected at depth interval of 0 to 12 inches were lower, but levels of mercury and lead are generally higher than the respective concentrations detected in the samples obtained from depths greater than 1 foot. Contamination also decreases with increasing distances from the vicinity of the operations area.
Groundwater
78 on-site groundwater samples were collected from 38 monitoring wells during four sampling rounds. Samples were analyzed for organic and inorganic compounds (Results are in Table 4, Appendix B). Metal sampling analyses were based on non-filtered samples as required by the EPA (12).
Analytical data indicate that more contaminants with higher concentrations are distributed in the water table aquifer in areas north and northwest of the operations area. Generally, contamination decreases with increasing depths and increasing distances from the operations area.
Surface Water and Sediments
In 1987, KSCI sampled surface waters from two locations in the L-shaped ditch, two oxidation ponds in the former mobile home park, and a wet weather depression in KSCI property (Figure 6). Several volatile organic compounds (VOCs) were detected in samples from the ditch (Table 4, Appendix B). No VOCs were detected in the pond samples (12).
In an effort to assess the source of odors that were detected near the L-shaped ditch, SCDHEC collected surface water samples from the ditch in 1988. Benzene and 1,2-dichloroethane were detected in the samples at levels of 6.6 µg/L and 50.4 µg/L, respectively. These levels were considered insufficient to account for the odors.
During the five sampling events conducted from October 1990 to November 1991, PBS&J collected five surface water samples (SW-1 through 5) and two sediment samples (SD-2 and SD-3, Figure 6). Sampling results indicate the presence of several organic compounds and elevated levels of lead and mercury. The highest concentrations occurred in the surface water sample SW-2 and the sediment sample SD-2 (Table 3, Appendix B) (12).
Air and Soil
PBS&J did not collect air or soil samples from off-site areas during the RI.
Groundwater
During the Remedial Investigation, PBS&J collected 40 groundwater samples from fifteen off-site monitoring wells and six local wells located to the north (well GR), east (MASL and MAB) and southwest (CW, CW-PROD and CW-DRINK - Figure 6). Wells CW and CW-PROD are screened in the limestone aquifer and are located approximately 700 feet to the southwest from well cluster MW-46, from which the highest levels of groundwater contamination were detected. Groundwater flow within the limestone aquifer beneath the site is toward the southwest as indicated by water level measurements during the RI. Therefore, the presence of 1,2-DCA at these two wells may be the result of contaminant migration from the site (12).
Low levels of acetone (ND-170 µg/L) and methylene chloride (ND-14 µg/L) were detected at several off-site monitoring wells and local wells (Table 4, Appendix B). However, these two compounds were also detected in the associated laboratory blanks. Therefore, the detection of acetone and methylene chloride in off-site groundwater samples may be attributed to laboratory contamination (12).
C. Quality Assurance and Quality Control
PBS&J conducted field work and sampling activities under Standard Operating Procedures (SOP) approved by EPA. All the samples were analyzed by Ecoter LSI, a member of the EPA Contract Laboratory Program (CLP). These procedures are required to be employed in all environmental investigation activities to ensure that samples are collected and analyzed accurately. SCDHEC assumes that adequate quality assurance and quality control measures were followed with regard to chain of custody, laboratory procedures, and data reporting.
Results of the analytical data present fair consistency between different sampling rounds and different media. However, high quantification limits for benzene, carbon tetrachloride, 1,1-dichloroethene, ethylbenzene (500 µg/L), and vinyl chloride (1,000 µg/L), utilized to groundwater sample MW-46A may mask the possible presence of those compounds in the sample. Similar findings were reported for soil and sediment sample analyses.
Additionally, the frequent detections of acetone, methylene chloride and bis(2-ethylhexyl)phthalate in blanks and samples may be indicative of possible laboratory contamination.
The ditch in the former mobile home park and the abandoned old operation house present a
physical hazard. People who enter the site may fall into the ditch or the hole in the floor of the
operation house.
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 include all 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
Because we could not define a receptor population, we do not believe that exposures have occurred, are occurring, or will occur. Therefore, no completed exposure pathways exist for the KSCI site at this time.
B. Potential Exposure Pathways
Table 5 summarizes the potential exposure pathways that exist at KSCI.
Soil Pathway
Past, present, and future exposures to contaminated soil are possible at the KSCI site. In the past, exposure to contaminants at the KSCI site could have occurred to anyone who may have wandered onto the site or to on-site workers. No data are available concerning the possible exposures and/or length of exposures; therefore, adverse health effects from past exposures to on-site soils cannot be evaluated. The routes of exposure could have been dermal contact with, ingestion of, or inhalation of soil particles.
Currently, exposure to contaminants in soil may occur to anyone who enters site. However, we feel that the likelihood of exposure to on-site soil contaminants is minimal because the site is vegetated. Frequent trespass onto the site is unlikely because the access to the site is restricted by the wooded area partially surrounding the site. Site vegetation and the surrounding forest are expected to prevent the migration of soil contaminants due to the effects of the wind. Therefore, exposures to the on-site soil contaminants through inhalation is not a concern at the present time. Soil contamination detected off-site may lead to exposure through ingestion or dermal contact with contaminants. However, there is currently to off-site surface soil data with which to evaluate this pathway.
In the future, potential exposure pathways could become completed if the site is developed. In particular, if future commercial or residential development of the property occurs, exposures to contaminated soil could occur if the soil is disturbed through construction or other activities.
Groundwater Pathway
Current and future exposure pathways for groundwater could exist. Available data do not indicate that past exposure to contaminants in groundwater is likely.
Currently, 1,2-DCA has been detected in wells CW and CW-PROD. Because these wells are only used for production purposes by the concrete company and not as a drinking water supplies, exposures through ingestion should not occur. However, the possibility of exposure through inhalation of 1,2-DCA vapors and through skin contact may exist. We have no data to confirm that exposures are occurring. Current and future human exposures may occur through inhalation or dermal contact with other contaminants in groundwater. Inhalation exposure is only likely to occur if the following conditions are met:
Sediment Pathway
Past, current, and future exposures to contaminated sediment are possible. Contaminated sediments detected in the ditch in the former mobile home park area present a potential for exposure through ingestion and skin contact to the people who enter the site and/or the ditch. However, we do not consider this to be a probable exposure scenario.
Surface Water Pathway
Past, present, and future exposures to contaminants in surface water are possible. In the past, exposure to contaminants may have occurred to anyone who ingested or had skin contact with contaminated surface water in the L-shaped ditch.
Currently, there are no known completed routes of human exposure associated with surface water. Several contaminants have been detected in the surface water samples collected from the L-shaped ditch. The ditch ultimately connects with a state highway drainage ditch and is not directly connected with a classified water body of the State. Because the ditch is not utilized for drinking water supplies, agricultural, industrial, or recreational purposes, the only potential for public exposure to the contaminated surface water would be through accidental ingestion and skin contact.
This potential exposure pathway could become completed in the future. Anyone who ingests or
has skin contact with contaminated surface water may be exposed to the identified contaminants.
However, this would not appear to be a significant pathway.
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-hundred risk.
ATSDR also develops Toxicological Profiles for 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.
The following discussions of chemicals rely on the preceding assumptions combined with the information in the Pathways Analyses section.
Benzene
Benzene is a naturally occurring substance produced by volcanoes and forest fires and is present in many plants and animals. It is also a major industrial chemical made from coal and oil and is found in gasoline, adhesives, household cleaning products, and art supplies (3).
No completed human exposure pathway exists for benzene; therefore, no adverse health effects are occurring at the present time. However, potential pathways could become completed in the future.
If the contaminated groundwater migrates off site and reaches private wells, ingestion of groundwater from those wells could lead to doses of benzene approximately five times EPA's 1-day and 10-day Health Advisories. ATSDR has not developed acute, intermediate, and chronic MRLs for benzene due to insufficient human and animal data studies. According to the ATSDR Draft Toxicological Profile for Benzene, levels of benzene approximately twenty-times greater than those at the KSCI have led to detrimental changes in the blood of exposed rats (3).
Exposure to benzene is associated with the development of cancer in humans and laboratory animals (3). The lifetime (70 years) ingestion of maximally contaminated groundwater would lead to an "moderate increased risk" of developing cancer. Doses received from other media would contribute much lower doses and could increase this risk by lower amounts.
1,2-Dichloroethane
1,2-Dichloroethane is a clear liquid that is not found naturally in the environment. It is used to make other chemicals, as a component in several solvents, and is a former ingredient in some pesticides (5).
Currently, no completed exposure pathway exists for this chemical. However, potential exposure pathways identified for 1,2-dichloroethane may become completed in the future.
Children who ingest maximally contaminated groundwater may experience adverse health effects. In mice, acute oral doses similar to those in groundwater have caused a decreased immune response. However, levels of 1,2-dichloroethane in groundwater are significantly less than levels that have caused a decrease in the number of white blood cells, serious effects on the immune system, liver damage, and death (3).
The ingestion of 1,2-dichloroethane from private wells if the highest levels found in on-site groundwater migrated to those wells, would not cause adverse, non-cancerous health effects in an adult. However, the theoretical, lifetime ingestion of maximally contaminated groundwater could lead to a highly significant risk of developing cancer.
1,1-Dichloroethylene
1,1-Dichloroethylene (DCE) is a chemical used to make other chemicals, such as some plastic wrap (6).
No completed exposure pathway exists for this chemical. However, potential pathways may become completed in the future if contaminated groundwater is ingested or if it comes into contact with skin.
A child who ingests contaminated groundwater would receive a dose four times greater than ATSDR's MRL. However, adverse health effects from exposure to the levels of DCE in groundwater are not anticipated to result in adverse health effects due to the wide variance in contaminant concentrations detected at the KSCI site and because of the safety factors used in deriving the MRL.
Some evidence suggests that DCE may cause cancer in laboratory animals (6). EPA lists DCE as a possible human carcinogen. Because of the lack of human data, the paucity of animal data, and the lack of a plausible chronic exposure pathway, we cannot address the risk of cancer at this site from future exposures.
Ethylbenzene
No completed exposure pathway was identified for ethylbenzene. Therefore, no adverse health effects are anticipated at the present time. However, potential pathways identified for this chemical may become completed in the future.
An infant exhibiting soil pica behavior (ingesting large amounts of soil) and ingesting maximally contaminated groundwater would receive a dose of ethylbenzene approximately ten times EPA's reference dose. ATSDR has not established an MRL for ethylbenzene. The December 1990 Toxicological Profile indicates that little human and animal toxicity is available. However, animal data suggest that the liver, kidney, and blood system may be adversely affected from exposure to ethylbenzene (7). However, these effects have not be documented in humans.
Methylene chloride
Methylene chloride is a commonly used solvent and paint stripper. Because many laboratories commonly use methylene chloride, it often appears as a contaminant in laboratory samples (10). Because the laboratory also detected methylene chloride in the associated laboratory blanks, this Health Assessment cannot assess the possible future health effects which may result from this compound at KSCI.
Vinyl chloride
Vinyl chloride is also known as monochloroethylene is mainly used to make polyvinyl chloride (PVC). PVC is used to manufacture a variety of plastic and vinyl products including pipes, wires and cable coatings, packaging materials, wall coverings and automotive parts (11).
No completed exposure pathways for vinyl chloride were identified. However, potential exposure pathways may be completed in the future if contaminated sediment is ingested or if it comes into contact with skin.
A child who ingests maximally contaminated sediment would receive a dose of vinyl chloride equal to ATSDR's chronic MRL. Therefore no adverse health effects are anticipated.
Because vinyl chloride appeared in a limited number of samples from only one specific medium, chronic exposure to this chemical appears highly unlikely. Therefore, carcinogenic effects will not be discussed.
Lead
Lead is a naturally occurring element found in most environmental media. It has a wide range of uses including storage batteries (automobile batteries), solders, pipes, various chemicals, and, formerly, gasoline additives (8).
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; it is also associated with hypertension in some adult males (8).
ATSDR has not established an MRL for lead and the EPA has not established a reference dose for lead. Although exposure to certain lead salts have been associated with an increased rate of cancer in laboratory animals, EPA has not estimated the carcinogenic potency of lead.
At KSCI, current exposure to lead is not currently of concern. Similarly, the lead levels are not of concern as long as the site remains vacant or industrial. However, if the site should become residential, the ingestion of lead from soil and possibly the limited ingestion of stream sediments would be of concern.
Mercury
Mercury is a chemical element that occurs naturally in several forms. The most familiar is the silvery liquid metal used in some thermometers and other common products. Mercury also occurs in combination with other elements. One form of mercury, methylmercury, can accumulate in certain fish (9). Analyses at KSCI did not differentiate between organic and inorganic mercury.
The levels of mercury found at the site are not of concern unless the site should become residential in the future. Even then, the levels of mercury would be of concern for a young child exhibiting soil pica behavior who ingests maximally contaminated soil. In this case, the child would receive a dose ten times the ATSDR's chronic MRL. Because testing did not show a widespread presence of mercury and because surface soil (0-3") samples were not analyzed as part of the remedial investigation, the actual dose may be much less than "the worst case" models. Therefore, mercury will not be considered of concern at the present time.
Sodium
Sodium is commonly found in nature combined with other chemicals. Sodium and chloride form table salt. Sea water contains large amounts of sodium.
Because of medical conditions, some people need to limit their sodium intake. For example, some people with high blood pressure often benefit from a low salt diet and should consult with their physician before ingesting groundwater containing the levels of sodium found at this site.
B. Health Outcome Data Evaluation
As there are no completed pathways, and no health outcome data exists for the KSCI site, health outcome data were not evaluated at this time.
C. Community Health Concerns Evaluation
SCDHEC records document citizen complaints' of "noxious odors" emanating from the site. These complaints began in 1973 and continued until KSCI closed in 1983. SCDHEC and PBS&J investigations could not determine the origin of the odors. We cannot address this issue at this time because of a lack of data. No other community health concerns were documented.
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