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1. ATSDR > Public Health Assessments & Consultations

PRELIMINARY PUBLIC HEALTH ASSESSMENT

PARA-CHEM SOUTHERN, INC.
SIMPSONVILLE, GREENVILLE COUNTY, SOUTH CAROLINA

The tables in this 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. SCDHEC and ATSDR select and discuss these contaminants based upon the following factors:

1. Concentrations of contaminants on and off the site.

2. Field data quality, laboratory data quality, and sample design.

3. Comparison of on-site and off-site concentrations with public health assessment comparison values for (1) non-carcinogenic endpoints and (2) carcinogenic endpoints.

4. Community health concerns

In the data tables that follow under the On-site and the Off-site Contamination subsections, the listed contaminant does not mean that it will cause adverse health effects from exposures. Instead, the list indicates which contaminants will be evaluated further in the public health assessment.

Comparison values for public health assessments are contaminant concentrations in specific media that are used to 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 the EPA's cancer slope factors. The EPA's MCLG is a drinking water health goal. The 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 concentration that the 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. The EPA's RfD is an estimate of the daily exposure to a contaminant that is unlikely to cause adverse health effects. RMEGs are media-specific comparison values derived from the EPA reference doses and are used to select contaminants of concern at hazardous waste sites.

The maximum concentrations of contaminants, both on- and off-site, are given in Table 1. Organic compounds and metals are listed.

Toxic Chemical Release Inventory (TRI)

We conducted a search of the EPA's Toxic Chemical Release Inventory (TRI) for the years 1988, 1989 and 1990. The search included a 1-mile radius from the site. TRI is developed by the EPA from chemical release information provided by certain industries. The chemical release information is based on contaminants found in air, surface water, groundwater, or and/soil.

TRI reports that PCS released 19 chemicals into the environment during this time period. These releases occurred: 1) as non-point releases, such as leakage around valve fittings and other joints; 2) through a scrubber with 75% efficiency; and, 3) in treated wastewater to an unnamed tributary of Durbin Creek. TRI also reports that PCS shipped wastes to waste disposal facilities and that Woodside Mills, a facility to the south of the site, had a non-point release of acetone into the environment in 1988. Based on our review of this data, we do not believe that there will be any significant impact on the environment.

A. On-site Contamination

Subsurface Soil

No soil samples meeting ATSDR's definition of surface soil were collected during preliminary investigations. ATSDR defines surface soil samples as those collected from 0"-3"; ATSDR considers that humans are most likely to be exposed to contaminants in soil at this depth.

The PCS site is located on a topographic high with elevations ranging from a high of 882 feet mean sea level (MSL) in the central portion of the site to a low of 826 feet MSL along a stream near the eastern boundary of the site.

In 1986, RMT performed an on-site electromagnetic survey and established the boundaries of three on-site locations that PCS had used to bury drums. RMT estimated that: 1) Area 1 was 15 feet wide and 100 feet long; 2) Area 2 was 15 feet wide and 140 feet long; and, 3) Area 3 contained two burial trenches, one that was 15 feet wide by 100 feet long and the other that was 15 feet wide by 22 feet long. Between March 1987 and July 1987, the GSX Corporation removed and disposed of wastes and associated soils from all three areas.

Table 2 presents the concentrations of contaminants of concern for on-site subsurface soil. The following data represent sampling from preliminary investigations.

Groundwater

Groundwater occurs in the saprolite and bedrock units at the site. The depth to the water table ranges from less than one foot adjacent to the stream near the site's eastern border, to approximately 21 feet deep near the central portion of the site. Groundwater flow patterns within deeper saprolite zones and bedrock have not been fully determined.

Degradation of groundwater has occurred in three different areas of the PCS site (Figure 3): 1) near the disposal areas and the two lagoons in the eastern portion of the site; 2) near the disposal area in the western portion of the site; and, 3) near the storage tanks west of the facility buildings in the central portion of the site. Several chlorinated hydrocarbon compounds appear to be the most widespread contaminants. The distribution of other organic compounds including 2-butanone, tetrahydrofuran, and toluene appears to be less extensive.

The highest concentrations of organic compounds have been detected in shallow groundwater in the eastern portion of the site (Figure 3). Available data indicate that these compounds have migrated north, east, and south of these source areas (Figure 3), impacting groundwater in the area south of the stream (tributary of Big Durbin Creek) from monitoring well 35-A (south of the disposal areas) north to the property boundary and beyond. Contaminant concentrations in shallow groundwater generally decrease with distance from the source areas, although some compounds are present over this entire area at levels exceeding the EPA's Maximum Contaminant Levels (MCLs).

Table 3 presents the concentrations of contaminants of concern for on-site groundwater. The following data represent sampling from preliminary investigations.

Surface Water

Surface water data were not available for review. This information will be examined as it becomes available.

Air

No air monitoring data were available for review; however, it does not seem likely that contamination would be a problem. We will reevaluate this medium should data become available. The EPA investigated odor complaints from residents but did not detect any air-release violations.

B. Off-site Contamination

Groundwater

Available data indicate that contaminants from PCS have migrated as far as 300 feet north of the northern site boundary. As observed in some on-site locations, contaminant concentrations are greater in groundwater within the deeper bedrock zone than in shallow groundwater.

Table 4 presents the concentrations of contaminants of concern for off-site groundwater. The following data represent sampling from preliminary investigations.

Table 5 presents the concentrations of contaminants of concern for off-site private wells. The following data represent sampling from preliminary investigations.

Air

No air monitoring data were available for review. The EPA investigated odor complaints from residents but did not find any air-release violations.

C. Quality Assurance and Quality Control

Quality Control and Quality Assurance (QA/QC) 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.

A number of laboratories, including SCDHEC, generated data for this site. Full QA/QC information has not been provided, although data generated by private contract laboratories appear to be consistent with those generated by SCDHEC laboratories.

The monitoring wells currently in use at the PCS site appear to be constructed according to SCDHEC standards and allow collection of representative groundwater samples. The procedures used to sample cannot be evaluated because a sampling and analysis plan is not available.

In the analysis of groundwater, it is possible that the detection limits for some highly contaminated wells (MW-21, MW-13, and MW-13A) may have been set too high by the contract laboratory used by PCS. Thus, the concentrations of some compounds could have been falsely reported at non-detectable levels.

D. Physical and Other Hazards

Project staff did not observe any significant physical hazards to the public or surrounding community during site visits. Points of entry to the plant site are restricted by a security building where visitors must gain access. The plant property is enclosed by a chain link fence at accessible points, although the north and east boundaries are not fenced. Security guards are present 24 hours a day and make walking rounds of the plant property. According to the president of PCS, vandalism has not been a problem and current security measures at the plant seem adequate.

To determine whether nearby residents are exposed to contaminants migrating from the site, ATSDR evaluates the environmental and human components that lead to human exposure. This pathways 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 population.

ATSDR categorizes an exposure pathway as a completed or potential exposure pathway if the exposure pathway cannot be eliminated. Completed pathways have all five elements and indicate that exposure to a contaminant has occurred in the past, is currently occurring, or will occur in the future. Potential pathways, however, have at least one of the five elements missing, but could become completed. Potential pathways indicate that exposure to a contaminant could have occurred in the past, could be occurring now, or could occur in the future. An exposure pathway can be eliminated if at least one of the five elements is missing and will never be present. The discussion that follows incorporates only those pathways that are important and relevant to the site. We also discuss some of those exposure pathways that have been eliminated.

A. Completed Exposure Pathways

In 1988, contaminants were detected in private drinking water wells at two residences along Howard Drive. However, the contamination has not been conclusively linked to the PCS site. Private well-use patterns in this area have not been examined adequately. Therefore, no conclusive indication of public exposure to site-related contaminants currently exists. However, exposures could potentially occur in the future via off-site, contaminated groundwater by ingestion, dermal (skin) exposure, or inhalation.

B. Potential Exposure Pathways

Groundwater Pathway

Groundwater presents the most likely environmental transport medium for the contaminants of concern. Sampling indicates that contaminants have migrated from the site. Exposures may occur if humans ingest or have dermal contact with contaminated groundwater.

Soil

No surface soil data are available for review. Subsurface soil contamination was detected on-site; however, the depth of these contaminants are not considered to be a pathway of concern. Although subsurface soil contamination may provide a continuing source of groundwater contamination, direct contact with subsurface soil contaminants is unlikely. Visitors and workmen do not appear to be at risk for exposure. Exposures through accidental ingestion and/or dermal contact with contaminated soil may occur in the future if the site is excavated.

Air

Industrial air releases for this facility are regulated by SCDHEC through the Bureau Of Air Quality Control. Currently, there is no indication of atmospheric contamination from non-plant operations.

A. Toxicological Evaluation

Introduction

In this section, we will discuss the health effects in persons exposed to specific contaminants, evaluate state and local health databases, and address specific community health concerns. To evaluate health effects, ATSDR has developed a Minimal Risk Level (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, such as ingestion and inhalation, and for the length of exposure, such as acute (less than 14 days), intermediate (15 to 364 days), and chronic (greater than 365 days). ATSDR presents these MRLs in Toxicological Profiles. These chemical-specific profiles provide information on health effects, environmental transport, human exposure, and regulatory status.

Analyses of environmental sampling data, demographic data, and plausible environmental pathway data show groundwater migration to be the most likely mechanism in which off-site populations may be exposed to the contaminants of concern. It is also possible, although somewhat unlikely, that significant windborne migration of contaminated dirt may occur.

Currently available evidence does not conclusively demonstrate exposures to any individual or group of individuals from site-related contaminants. Since no individuals are currently known to be exposed to contaminants, there are no health effects expected at the present time. However, the following discussion of health effects is presented using a "worst-case scenario," that is, individuals consuming water containing contaminants at concentrations equivalent to the maximally-contaminated, on-site groundwater.

Lead

Lead is a naturally occurring element that is 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 1993a).

Lead is a cumulative toxin. Chronic ingestion of low levels of lead by children may result in various neurobehavioral deficits, decreased growth, and alterations in enzyme activities. ATSDR has stated that blood lead levels of 10 to 15 micrograms per deciliter (µg/dL) (or possibly lower) may be associated with neurobehavioral deficits. ATSDR has defined preschool-age children and fetuses as groups at special risk. White males between 40 and 59 years of age appear to be at risk to the hypertensive effects of lead. Lead acetate and lead phosphate have been demonstrated to be animal carcinogens, although the evidence for similar effects in humans is inadequate (ATSDR 1993a).

Lead was detected in on-site groundwater and monitoring wells on adjacent, off-site property at concentrations exceeding federal drinking water levels. ATSDR has not set an MRL for lead. The EPA has not set a reference dose (Rfd) for lead. However, the EPA has established an action level of 15 ppb for lead in drinking water.

Sulfate

Ingestion of high levels of sulfate in water and infant formula have caused diarrhea and dehydration in animals and humans, with infants showing a greater sensitivity. In adult humans, individuals have become acclimated to high sulfate levels in a short period of time, resulting in a cessation of ill effects. Infants appear to be more sensitive to the toxic effects of sulfate than adults; several cases of diarrhea and gastroenteritis have been reported in human infants, ages 5 months to 12 months old, consuming formula prepared with water containing 630,000 to 1,150,000 ppb. The effects ceased when this high-sulfate water was no longer used (55 FR 30370).

Ingestion of drinking water containing sulfates at the concentrations reported from on-site wells could produce diarrhea, especially in infants. Sulfate concentrations exceed federal drinking water limits.

Benzene

Benzene is present in a wide variety of common products, including gasoline. Benzene is a highly flammable, colorless liquid with a sweet odor. Benzene is man-made but also occurs naturally in the environment (ATSDR 1993b).

The primary health concerns from long-term exposure to low concentrations of benzene are potential chromosomal damage, bone marrow depression, and the development of leukemia in a significant number of exposed individuals. The EPA classifies benzene as a human carcinogen on the basis of sufficient human epidemiologic evidence (ATSDR 1993b).

Human exposure to benzene could occur in the future if contaminated, on-site groundwater is used for drinking water purposes; however, this is unlikely. Therefore, there is no reason to suspect exposure to benzene at the present time. Benzene concentrations in on-site subsurface soil range up to 173 ppm. Surface soil data are not available.

Toluene

Toluene is a clear, colorless liquid with a sweet smell. It is a gasoline additive and is used for making other fuels from crude oil. It is also used in making coke from coal, and as a by-product in the manufacture of styrene. It is used in the making of paints, lacquers, adhesives, rubber, paint thinners, and in some printing an leather tanning processes (ATSDR 1993c).

The EPA has proposed an MCL of 2,000 ppb for the protection against adverse effects for exposures occurring over a lifetime. The maximum concentration of toluene in on-site groundwater is 16,000 ppb. Toluene concentrations of up to 65 ppm were detected in on-site subsurface soil.

Acute exposure to high levels of toluene in animals results in central nervous system depression and effects on the lungs, liver, and kidney. Toxic effects following chronic exposure are similar to those seen following acute exposure. Although toluene is chemically similar to benzene, test animal exposure to toluene has not been associated with the development of cancer.

Chlorinated Aliphatic Compounds

Chlorinated aliphatic compounds share similar toxicologic, chemical, and environmental properties. This class of chemicals includes chloromethane, methylene chloride, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1-dichloroethylene, trichloroethylene, and tetrachloroethylene.

Ingestion of these compounds produce, to varying degrees, toxicity of the liver, kidney, and central nervous system. In the case of dichloroethylene, trichloroethylene, and tetrachloroethylene, significant renal toxicity is not a predominant effect.

The EPA has derived a methodology for a series of Drinking Water Health Advisories. Health Advisories describe nonregulatory concentrations of drinking water contaminants at which adverse health effects would not be anticipated to occur over specific exposure durations. The possible toxic effects from ingesting "worst-case" groundwater contaminants may be assessed by comparing the maximal on-site concentrations to the relevant Health Advisories or limits. Because of the conservative assumptions included in the Health Advisories, ingestion of water containing contaminant concentrations up to and slightly above the Health Advisory are not likely to cause organ damage. However, as the concentration increases, the likelihood of organ damage also increases.

At this site, concentrations of 1,1-dichloroethylene exceed the one-day health advisory for a 10 kilogram child. Additionally, the maximum concentrations of methylene chloride, carbon tetrachloride, 1,1,1-trichloroethane, and tetrachloromethane range from 42% to 60% of their respective one-day health advisories. Therefore, ingestion of on-site groundwater and the future possibility of contaminant migration to off-site wells represents a potential public health concern.

The EPA has classified both 1,1-dichloroethylene and 1,1,2-trichloroethane as possibly carcinogenic to humans (Group C). This classification includes chemicals in which there is limited evidence for animal carcinogenicity in the absence of human data.

On the basis of laboratory animal data, the EPA has classified methylene chloride, chloroform, carbon tetrachloride, 1,1-dichloroethane, trichloroethylene, and tetrachloroethylene as probable human carcinogens (Group B2). This classification includes chemicals in which there is sufficient evidence for carcinogenicity in animals but insufficient evidence in humans.

Methyl Ethyl Ketone

Methyl Ethyl Ketone (MEK) is a colorless liquid with a sweet, but sharp odor. ATSDR has not established an MRL and the EPA has not established a reference dose for this chemical.

The maximum on-site concentrations of MEK was found to be 140,000 ppb which exceeds both the lifetime and one-day health advisories. Therefore, ingestion of drinking water containing maximally contaminated on-site groundwater may result in dizziness and/or vomiting.

Tetrahydrofuran and Methylcyclopropane

Inadequate toxicologic data are available for the evaluation of tetrahydofuran or methylcyclopropane.

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 1985, residents living near the site expressed concerns about odors from the PCS site. EPA air sampling did not reveal a need for any action beyond the ongoing cleanup.

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