PETITIONED PUBLIC HEALTH ASSESSMENT
BASKET CREEK SURFACE IMPOUNDMENT
BASKET CREEK DRUM DISPOSAL
DOUGLASVILLE, DOUGLAS COUNTY, GEORGIA
Contaminants of concern are contaminants found on or off site at concentrations that might pose a threat to public health. The presence of a contaminant on or off site does not imply that a health threat exists. This petitioned public health assessment will evaluate all contaminants of concern at the Basket Creek sites in an effort to determine if there is any threat to public health. ATSDR selects and discusses contaminants using the following information:
- concentrations of contaminants on and off the site;
- field data quality, laboratory data quality, and sample design;
- comparison of on-site and off-site concentrations with public health assessment comparison values for (1) noncarcinogenic endpoints and (2) carcinogenic endpoints; and
- community health concerns.
In this section, comparison values used in ATSDR public health assessments will be compared to contaminant concentrations in specific media (e.g., air, soil, groundwater) used to select contaminants for further evaluation. ATSDR and other agencies developed the comparison values to provide guidelines for estimating the media concentrations of a contaminant that are unlikely to cause adverse health effects, given a standard daily ingestion rate and a standard body weight. However, the fact that the concentration of a chemical exceeds a given comparison value does not imply that it is likely to produce adverse health effects. See Appendix C for a description of the comparison values used in this petitioned public health assessment.
ATSDR examines the Toxic Chemical Release Inventory (TRI) to determine if there is any information on sources of potential contamination in the vicinity of the site or sites under investigation. The TRI contains information on estimated annual releases of toxic chemicals to the environment (via air, water, soil or underground injection) that are voluntarily reported to EPA by the companies that release the chemicals. The TRI data give a general idea of environmental emissions occurring at or near a site. TRI data also may be used to determine whether ongoing emissions from reporting facilities might be contributing additional environmental contamination at the site.
ATSDR searched the TRI and found no reports of facilities releasing chemicals in the Basket Creek area. The nearest reported chemical releases were in the city of Douglasville, approximately 15 miles from the sites (TRI 1992).
The quality of on-site groundwater cannot be evaluated because there are no wells on either site. Likewise, there are no on-site surface water bodies from which surface water or sediment samples could be taken. Occasionally, surface water and sediment are collected from pools of precipitation (e.g., rain or snow) in order to evaluate runoff. However, no on-site samples of that type have been taken from the Basket Creek sites.
The Georgia Department of Natural Resources sampled subsurface soil at the surface impoundment in 1985. EPA sampled subsurface soil at both sites as early as 1990. No surface soil samples have been taken, primarily because backfill material covers both sites. However, some drums were protruding from the surface of the drum disposal area, indicating that surface soil may have been contaminated.
In further evaluating soil contamination, ATSDR will first discuss sampling results at the drum disposal area. ATSDR will discuss the sampling chronologically, beginning with sampling that occurred prior to removal actions, followed by sampling that was conducted after removal actions (post sampling). Post sampling includes sampling of the fill dirt and the final confirmation sample (sampling that shows the condition of the surface soil after the fill dirt was regraded). Lastly, ATSDR will discuss sampling conducted at the surface impoundment.
Sampling conducted by EPA in March 1990 and September 1991 at the drum disposal area revealed concentrations of arsenic, beryllium, polychlorinated biphenyls (PCBs), trichloroethene, and tetrachloroethene that exceeded ATSDR comparison values (EPA 1990; CWMI 1991b). Aluminum, iron, and lead were detected in subsurface soil at the drum disposal site and will be evaluated as contaminants of concern (although no ATSDR comparison values are currently available) (EPA 1990; CWMI 1991b). Methyl ethyl ketone will not be evaluated as a contaminant of concern for the drum disposal area due to invalid results (see the Quality Assurance and Quality Control subsection of this petitioned public health assessment for more information). Aluminum, arsenic, beryllium, and iron are naturally occurring elements and the concentrations at which they were detected are within background concentration ranges for U.S. soil (ATSDR 1988, 1989a, 1992m). A summary of contaminants detected or analyzed for at the drum disposal area prior to removal actions is shown in Table 1 (Appendix B).
The removal action at the drum disposal area was completed by sections or areas (three areas); the affected soil was removed, the bottom of the excavated area was sampled, and then the excavated areas were backfilled by covering them with soil from a nearby location. Post-removal action sampling was conducted at Area One during October 1991; it revealed only low levels of metals. However, there was no analysis of some of the contaminants (ethylbenzene, tetrachloroethene, toluene, and trichloroethene) that were previously detected in soil at the drum disposal area. Prior to removal actions, trichloroethene and tetrachloroethene in subsurface soil had exceeded comparison values (CWMI 1992a). Area Two post-removal action sampling (May 1992) found 1,1,2,2-tetrachloroethane, di(2-ethylhexyl)phthalate (DEHP), PCB aroclor 1242, PCB aroclor 1248, and some metals below comparison values. The concentration of PCB aroclor 1242 in one sample was slightly above its comparison value. Two other samples show concentrations of arsenic well above comparison values (71.3 and 89.8 mg/kg) (CWMI 1992b). Analysis of post-removal action samples from Area Three (January 1992) found xylene, DEHP, PCBs (aroclor 1248 and 1254), and three metals at levels below comparison values. One sample contained PCB aroclor 1248 at a level slightly greater than the comparison value; two samples contained PCB aroclor 1254 at levels slightly greater than the comparison value (CWMI 1992c). The contaminant levels for each area met the cleanup standards that were pre-established by ATSDR for the Emergency Removal Phase of EPA operations (see ATSDR Record of Activity for 10/30/91 and 4/6/92 in Appendix D).
The fill dirt was sampled in May 1992 and no contaminants exceeded comparison values. Lead, a naturally occurring element was detected at low levels (ranging from 9.7-46.3 mg/kg) in the fill soil and at each of the three areas (CWMI 1992d). The drum disposal area was covered with soil at an average depth of 10 feet. A final surface soil composite sample was taken by EPA in July 1992. One contaminant, beryllium, was detected at a concentration (2.6 mg/kg) exceeding an ATSDR comparison value. However, beryllium is a naturally occurring element and is found naturally in U.S. soil at levels higher than that value. Based on that information and the fact that the composite sample is local fill soil, it would appear that beryllium is natural at the levels detected in the soil for this area of Douglas County. Therefore ATSDR will not evaluate beryllium as a contaminant of concern for soil in this petitioned public health assessment. The results of the sampling are summarized in Table 2 (Appendix B). The drum disposal site removal action was completed, as required and specified by EPA; a Letter of Completion was sent to Chem-Nuclear Systems, Inc., on August 21, 1992 (ATSDR 1992g).
Subsurface soil samples have been collected at the surface impoundment by the Georgia Environmental Protection Division and EPA on three different occasions, beginning in October 1985; the most recent samples, prior to removal actions, were collected in January 1992. Acetone, arsenic, benzene, DEHP, ethylbenzene, mercury, PCB aroclor-1260, tetrachloroethene, toluene, selenium, and trichloroethene exceeded their respective comparison values (EPD 1985f; EPA 1990; EPA 1992a). Some contaminants (aluminum, iron, lead, and methyl ethyl ketone), for which no comparison values are available, will also be evaluated as contaminants of concern. The concentration at which aluminum was detected at the surface impoundment was within the natural background concentration range for U.S. soil; however, iron and lead concentrations are above the natural background concentration range for U.S. soil (ATSDR 1992m). A summary of subsurface soil samples at the surface impoundment is shown in Table 3.
EPA constructed a temporary building around the surface impoundment to control volatile chemicals during excavation. On November 22, 1992, EPA began removal operations by excavating contaminated soil throughout the impoundment in 10 x 10 foot grids. Contaminated soil was excavated from the impoundment at depths ranging from 6-12 feet. Soil from the bottom and walls of each grid was sampled and backfilled, although bedrock was reached in some areas and samples could not be obtained. Based on sampling results, two areas had to be re-excavated in March and April 1993, to meet pre-established cleanup levels (see health consultation 12/11/92 in Appendix D).
Contaminated soil was stockpiled within the building and ventilated to remove vapors to a thermal oxidation unit which burned the vapors outside the building. Contaminated soil from the surface impoundment was transported to an industrial waste landfill in Buford, Georgia.
Once the building and equipment was removed from the site, additional fill material was brought in to reduce the slope during regrading and landscaping. Final site activities were concluded on September 16, 1993 (EPA 1993a).
The Georgia Department of Natural Resources analyzed air samples when the drum disposal site caught fire in March 1985. The analysis showed unspecified concentrations of carbon monoxide, trichloroethene, and chloroform (EPD 1985g).
Air monitoring and sampling were conducted during removal activities at the drum disposal area. The air monitors provide immediate readings of the total VOCs detected in the air, while air sampling is conducted for a period of time (hours) to capture a sample of the contaminants that are later analyzed by a laboratory. Hourly monitoring for organic vapor readings and particulates was conducted at 10 locations around the perimeter of the exclusion zone. EPA reported no high readings at the site perimeter; on a couple of occasions, contaminants detected were slightly greater than background levels (ATSDR 1992h).
Air sampling (time-weighted) was conducted in the exclusion zone. According to a summary of the air monitoring procedures, target compounds that were tested for included toluene, xylene, benzene, naphthalene, o-dichlorobenzene, p-dichloro-benzene, 1,2-dichloroethene, and 1,1,2-trichloroethane. Of those compounds, only toluene and xylene had been detected in the soil at the drum disposal area. Trichloroethene and tetrachloroethene must have later been included in the testing because they were included in the report of the site analyses. The time-weighted average sample pump was attached to the trackhoe (excavation equipment) to evaluate the air in the exclusion zone for worker safety purposes. ATSDR reviewed air sampling reports, for the exclusion zone, dating from September 18, 1991, through December 19, 1991. Toluene, xylene, trichloroethene, and tetrachloroethene were detected; however, no contaminants exceeded the Occupational Safety and Health Administration's Permissible Exposure Limit (see the November 19, 1991, Health Consultation for other information on air monitoring and sampling at the drum disposal area)(CWMI 1991c).
Air sampling and monitoring on site at the surface impoundment began during the trial burn of EPA's thermal oxidation system (October 21-22, 1992) and continued throughout the soil excavation and vapor extraction process. Monitoring included real-time air monitoring in and around the building. Air was monitored in the building to ensure that low oxygen or high VOC levels were not a threat to workers or to the public. The monitoring was also conducted for the presence of mercury vapor. Oxygen and contaminant levels and excavation operations in the building were maintained in accordance with the site safety and contingency plans (OHM 1992; Weston 1992a). Air monitoring around the outside perimeter of the building was conducted every hour during excavation to ensure that no VOCs were escaping the building or duct work outside of the building. ATSDR staff worked closely with EPA and were on site during most of the excavation activities (see health consultations 10/13/92 and 11/18/92 in Appendix D for additional information). Based on data reviewed by ATSDR, monitoring did not reveal elevated levels of VOCs in air outside of the building (Weston 1992b).
During October 1985, two off-site soil samples were collected, one at a depth of 3 feet from approximately 100 feet downslope of the surface impoundment and one from an area to the north, uphill of the site, at an unspecified depth (EPD 1985f). No contaminants were detected at concentrations greater than detection limits. Lead and mercury were not analyzed for by a dry weight analysis.
In February 1992, two subsurface soil samples were taken downgradient of the surface impoundment. One sample was a composite of several grab samples taken from a test trench excavated in the dam face below the surface impoundment. The other was a composite from four test pits, which were dug to a depth of two feet. The test pits were in an area below the dam where empty, rusted drums had been seen on the surface. No contaminants detected in the samples exceeded comparison values (ATSDR 1992g).
EPA conducted additional investigations to search for other possible waste burial sites. The area investigated was an open trench identified in 1974 and 1976 aerial photographs. The EPA Technical Assistance Team conducted an informal geophysical survey of the suspected burial area on October 27, 1991. On May 18, 1992, seven test trenches were dug in the suspected burial area; household trash and debris were found in three trenches. An Organic Vapor Analyzer was used to analyze air quality in and around the test trenches. No readings greater than background levels were detected. Because no hazardous materials were excavated, or indicated visually or by air monitoring, the investigation was concluded (Weston 1992c).
Table 4 (all tables are in Appendix B) was developed by making a list of the different contaminants of concern as found in all media (soil, groundwater, etc.) and reporting the maximum concentration detected in the private wells for each contaminant. The groundwater contaminants of concern (aluminum, beryllium, iron, lead, molybdenum, trichloroethene, and zinc) are those that were detected in groundwater and exceed comparison values or those for which no comparison values are available. Those groundwater contaminants of concern for each private well are shown in Table 5. Tables 4 and 5 are used to assist the following discussion of off-site groundwater contamination.
The earliest well water sampling took place in October 1985 at well number 14 (refer to Figure 4, Appendix A, for well locations). Analyses were conducted for volatile organic compounds, PCBs, and metals; no comparison values were exceeded (EPD 1985f).
Samples were taken from two wells (numbers 3 and 14) during March 1990 and analyzed for contaminants similar to those noted previously. The results showed DEHP (in both wells) and trichloroethene (in well number 3) exceeding comparison values. However, the DEHP sample was invalidated due to contamination of the laboratory blank (see the Quality Assurance and Quality Control subsection of this petitioned public health assessment for more information) and therefore will not be evaluated as a contaminant of concern in groundwater (EPA 1990).
Since 1990, 19 private wells within a 1-mile radius of the Basket Creek sites have been sampled. The locations of those wells are shown in Figure 3 (Appendix A). Each well has been sampled at least twice since 1990; some wells have been sampled as many as five times. A few rounds of samples were analyzed only for metals and VOCs, but usually analyses for semi-volatile organic compounds, pesticides, PCBs, and special analyses (usually cyanide) were also conducted. Based on a review of those results, metals, many of which are found naturally in groundwater, were detected in every well. In addition, two VOCs were detected in one private well (EPA 1992b). Filtering samples usually results in lower levels of metals being detected; however, none of the water samples were field filtered (ATSDR 1992i).
From the 19 wells sampled, concentrations of beryllium, lead, zinc, molybdenum, and trichloroethene exceeded comparison values in the off-site groundwater. There are no drinking water comparison values for iron and aluminum, which were also detected in off-site groundwater; however, they also will be evaluated further in the Public Health Implications section as contaminants of concern.
Based on all of the off-site groundwater sampling, volatile organic compounds (cis-1,2-dichloroethene and trichloroethene) were detected in only one well -- number 3 -- the only well downslope and downgradient of the surface impoundment. The presence of VOCs in the well suggests that it might have been contaminated with waste from the surface impoundment. Mercury, a site-related contaminant, also was detected in well number 3. It was detected only once, and the concentration was less than its comparison value, but greater than typical background levels. Analysis of samples from the well closest to the surface impoundment (number 14), which is approximately 75 feet upgradient of the surface impoundment, did not show any contaminants at concentrations greater than drinking water comparison values (EPD 1985f; EPA 1990; EPA 1992b).
Again, based on all off-site groundwater sampling, analysis of samples from some of the private wells further from the site, yet within the 1-mile radius, showed metals in varying concentrations. Many of the metals detected occur naturally in the groundwater or have other sources and may or may not be site-related. Lead was detected seven times in four different private wells. In some instances, water samples were collected from household water fixtures; that could indicate that lead is leaching into the water supply from piping or solder. For example, lead was found in a sample from well number 8 at 66 µg/L; the sample came from a water spigot outside the house rather than from the well head. However, no lead was detected in two previous samples taken from the well or in two subsequent samples (one taken from the well and one from the kitchen tap). During a site visit on February 24, 1992, ATSDR staff examined plumbing in this home and discovered the use of lead solder on the copper plumbing (see Appendix D for 2/24/92 Trip Report). The high lead value (66 µg/L) found in the water at that home is likely to have resulted from lead leaching from the solder.
Beryllium was detected in only one sample from one well (EPA 1992b). Beryllium is sometimes found naturally in drinking water at levels similar to the one reported (1.2 µg/L). Based on the information available, the source of beryllium in the water cannot be determined for certain, but it is likely to be naturally occurring.
The levels of aluminum detected in the private wells are much greater than those typically found in groundwater with a neutral pH. However, groundwater that has a low pH or an area that receives acid rain and other acidic precipitation may have concentrations of aluminum close to the upper range of those detected near this site (ATSDR 1991c). The pH at the wells sampled ranged from 5.8 (slightly acidic) to 7.0 (neutral); the average pH was 6.4 (ATSDR 1992i).
Levels, well above comparison values, of zinc were found in three samples from two different private wells (wells 1 and 2). Based on U.S. studies, the levels of zinc detected in those private wells are much greater than those typically detected in groundwater, but are within U.S. surface and groundwater ranges (ATSDR 1989b). Samples from wells 1 and 2, which are approximately three quarters of a mile to a mile from the sites, revealed levels of molybdenum and zinc that exceeded comparison values.
In October 1985, water from a seep (approximately 600 feet downgradient of the surface impoundment) was sampled. The sample was analyzed for metals, unspecified PCBs, and VOCs. Mercury which was detected at elevated levels at the surface impoundment was not analyzed for in surface water. No contaminants exceeded comparison values (EPD 1985f).
On March 29, 1993, EPA conducted surface water sampling downgradient of the surface impoundment. Two samples were collected, one just below the surface impoundment and the other approximately one quarter mile downstream (EPA 1993a). Both samples were analyzed for volatile and semi-volatile organic compounds, pesticides, PCBs, metals (including mercury), and cyanide. No contaminants exceeded comparison values (EPA 1993b).
A spring downgradient of the drum disposal area was sampled in March 1990. No contaminants (with valid results) exceeded comparison values; however, aluminum and iron will be evaluated further since they have no comparison values. Mercury, although at low concentrations, was detected at the drum disposal area and at the spring, possibly indicating migration of this contaminant. Other contaminants might have been present at both locations, but could not be evaluated because of problems with the subsequent analyses (see the Quality Assurance and Quality Control subsection of this petitioned public health assessment for more information)(EPA 1990). Table 6 summarizes findings related to the spring sample.
One sediment sample was taken from the spring downgradient of the drum disposal area in March 1990. The sediment had a beryllium concentration of 0.78 milligrams per kilogram (mg/kg), which exceeds the CREG (comparison value) of 0.16 mg/kg. However, beryllium concentrations (in soil) up to 2.6 mg/kg is regarded as local natural background and will not be evaluated further in this petitioned public health assessment. No comparison values are available for aluminum, iron, and lead and although they are likely to be naturally occurring at the concentrations detected, they will be evaluated further as contaminants of concern. Methyl ethyl ketone will not be evaluated as a contaminant of concern in sediment due to invalid results (see the Quality Assurance and Quality Control subsection of this petitioned public health assessment for more information). Table 7 summarizes findings related to the sediment sample.
One air monitor (time-weighted sampling) was placed off site close to the residence nearest the drum disposal site. Samples were taken during removal activities. The contaminants found at the highest concentrations in on-site soil at the drum disposal area are believed to have been analyzed, (see the previous discussion of on-site ambient air); however, an analysis was not conducted for all site-related contaminants. ATSDR reviewed air sampling reports dating from September 18, 1991, through December 19, 1991; no contaminants were detected at concentrations greater than detection limits (CWMI 1991c).
Eight-hour to ten-hour, time-weighted air sampling was conducted at four locations off site near the surface impoundment. This sampling began during the trial burn of EPA's thermal oxidation system (October 21-22, 1992) and continued throughout the excavation and treatment process, which began on November 20, 1992. Three of the monitors were permanently located in approximate northerly, southerly, and westerly directions. The monitors to the north and south were at nearby residences. The fourth monitor was occasionally moved to different locations around the area. No contaminants were detected at concentrations greater than detection limits at any of the sampling locations; contaminant concentrations greater than detection limits were found in one set of laboratory results that are suspected to have been contaminated in the laboratory or involve laboratory error (see the Quality Assurance and Quality Control subsection of this petitioned public health assessment for more information) (Weston 1992b).
Since VOCs were not found to migrate off site, sampling later in the project was reduced to semi-weekly in the upwind and downwind directions. No elevated levels were reported (Weston 1992b; EPA 1993a)
During preparation of this petitioned public health assessment, ATSDR relied on the information provided in the referenced documents and assumed that adequate quality assurance and quality control (QA/QC) measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The validity of the analyses and conclusions in this petitioned public health assessment are determined by the completeness and reliability of the referenced information.
QA/QC review of EPA's March 1990 data revealed contaminant concentrations in the laboratory blank at levels that invalidated the results for methyl ethyl ketone and acetone in the sediment, water samples, and in soil samples at the surface impoundment; and for DEHP in the water samples and a soil sample from the drum disposal area. Aroclor 1254 and five pesticides were among the chemical constituents analyzed for; however, because of contamination of surrogate and spike data, the results were invalidated.
Groundwater at the Basket Creek site has been analyzed on a number of occasions. Arsenic, a contaminant of concern in soil at the drum disposal area, was not detected in any of the groundwater analyses; however, the minimum quantifiable level of 6 µg/L is somewhat greater than the comparison value of 0.02 µg/L. Therefore, levels of potential concern may not have been detected through the analyses.
Air sampling at the drum disposal area during the removal action was not totally sufficient to evaluate possible effects on public health. Air samples taken at the site were reported to have been analyzed (per the air monitoring plan) for eight volatile organic compounds; only two were detected in on-site soil samples. Review of the data analyses show two additional site-related contaminants reported in air sampling results. In order to accurately evaluate air quality, all compounds detected in the soil should have been analyzed for in the air samples. Because metals also were discovered in on-site soil, inorganic volatile compounds and particulates should have been analyzed for to determine whether off-site migration was taking place. Those recommendations and other public health issues were addressed in an ATSDR health consultation written on November 19, 1991 (see health consultation in Appendix D for additional information).
A set of laboratory results, reported for off-site time-weighted air samples collected during the surface impoundment removal activities, are suspected to have been contaminated in the laboratory. The EPA Technical Assistance Team reported proper chain-of-custody and handling procedures. However, the Technical Assistance Team also investigated laboratory procedures and reported the following findings: 1) The laboratory analyzed a highly contaminated sample before analyses of the time-weighted off-site samples; 2) no laboratory blanks were analyzed between samples to verify that the laboratory equipment was free of contamination; and 3) the times reported between samples were too close together to allow for analysis of blanks. Because of the deficiencies in the information provided, ATSDR did not evaluate that data set.
ATSDR staff saw no physical hazards at the Basket Creek sites. During soil removal at the drum disposal area, the site was separated into zones. The actual work area -- the contaminated or exclusion zone -- was restricted and taped off. The zone outside of that -- the clean support zone -- was monitored and access to it was controlled during work hours. ATSDR received no reports of unauthorized people gaining access to the site; nonetheless, people could have trespassed after work hours. Personnel and visitors signed in and out on the site log (CWMI 1991a).
The work site at the surface impoundment was restricted on three sides by an 8-foot fence.
During excavation and vapor extraction activities, the surface impoundment was enclosed in a
building. The contaminated soil was excavated and stored inside the building. Site safety and
contingency plans were in place to protect the community and on-site personnel from hazardous
conditions. Airflow within and leaving the building (through duct work) was regulated by fans
and monitored for explosive levels of VOCs to prevent explosion and fire hazards. People who
worked inside the building were required to wear "level B" protective equipment; workers in the
area immediately surrounding the building were required to wear "level D" protective equipment.
Personnel monitored operations on site 24 hours a day. Access to the site was controlled; people
who worked at or visited the site signed in and out on the site log book (OHM 1992; Weston 1992a).
To determine human exposure, ATSDR evaluates the pathways by which people may be exposed (from the source of contamination to the exposed population). ATSDR recognizes a "completed" pathway when five elements exist: (1) a source of contamination; (2) transport through an environmental medium; (3) a point of exposure to the human body; (4) a route of entry into the human body; and (5) an exposed population. A completed pathway may currently exist, may have existed in the past, or may be likely to exist in the future. A potential pathway is missing at least one element, but that element could have existed in the past, could currently exist (undocumented), or may exist in the future. A pathway is eliminated when at least one of the elements doesn't exist, and was unlikely to have existed in the past or to exist in the future.
The soil at the site is the dense red soil of the Madison soil series, which is characterized by a low infiltration rate (EPD 1986). The dense red clay grades down into partially weathered rock (saprolite) that overlies metamorphic bedrock (EPA 1991a).
Groundwater flow at specific sites has not been characterized, but some information is known about the area. The Brevard Fault runs through the site northeast to southwest. The fault is intersected by 90-degree joint sets, resulting in a rectangular drainage pattern. Evidence suggests that parallel fractures run parallel to the Brevard Fault and could further diversify groundwater flow directions. Groundwater flow in the area is considered fractured flow because the water tends to follow the fractured bedrock and weathered structuring.
The pumping action of wells typically creates a relatively uniform and symmetrical hydraulic influence on the groundwater surrounding them. In a fractured flow system, the pumping action of wells has a narrower, elongated hydraulic influence because water is pulled down the fractures in an almost channel-like flow. That pattern could result in groundwater being pulled into wells from a distance greater than normal.
Contaminants exceeding drinking water comparison values were detected in 11 of the 19 private wells sampled. Only five of those wells contained contaminants, other than aluminum and iron, that exceeded comparison values. Aluminum and iron are naturally abundant in soil and can leach into groundwater.
Other contaminants detected in the groundwater were beryllium, lead, molybdenum, and zinc. Beryllium was detected in only one well; the level was similar to maximum concentrations found naturally in a study of a number of water systems (ATSDR 1988). Therefore, beryllium found in the drinking water is not likely to be site related. Low concentrations of lead also naturally occur in soil, but most lead is strongly retained by soil. Some forms of lead and lead compounds, such as those formed at hazardous waste sites, are soluble in water and can leach through the soil (ATSDR 1990a). However, the highest concentration of lead found in the drinking water at Basket Creek was detected in water taken from the spigot at a house where lead solder is used in the plumbing. The source of lead in drinking water at three other homes, with maximum concentrations of 8.5, 13, and 24 µg/L, has not been determined. Zinc and molybdenum were not among the metals analyzed for in the on-site soil samples. From the available data, and the lack of groundwater characterization, none of the contaminants found in the private well water samples can be directly linked to the Basket Creek sites.
Well number 3, from which samples showed low concentrations of trichloroethene and cis-1,2-dichloroethene, is the only well believed to have been affected by site contaminants. The potential for further contamination of well number 3 and other wells cannot be determined without groundwater characterization or continued sampling.
Although the source or sources of contamination in groundwater near the Basket Creek sites cannot be confirmed, the private wells have been used for drinking and other domestic purposes (cooking, bathing) in the past; as a result, people were exposed in the past through dermal contact, ingestion, and inhalation. Douglas County supplied temporary drinking water to the community in July 1991; in August 1992, all homes in the area were connected to county water lines. Therefore, residents should no longer be exposed to contaminants through groundwater use (ATSDR 1992j, 1992k). An estimated 27 persons may have been exposed to contaminated drinking water at the residences in the past.
Molybdenum and zinc were detected at levels exceeding comparison values in well numbers 1 and 2. Those wells are located at a corporate-owned retreat facility. People using water from those wells are considered the receptor population. The number of people who may have used water at the retreat facility is not known.
Soil was contaminated at both sites. People may have been exposed to site-contaminated soils at the surface impoundment before it was backfilled in 1976, or at the drum disposal area, where drums were not completely covered with backfill and may have released contaminants to the surface soil. No surface soil was sampled at either waste site; therefore, contamination of surface soil and possible exposures resulting from contact with surface soil cannot be determined.
The greatest potential for exposure would have been while the impoundment was uncovered; to date, there have been no reports of exposure. Sometime in the mid-1980s, a teenager planted a small garden in the soil above the surface impoundment (ATSDR 1992l). Prior to site cleanup the depth of soil covering the impoundment was reported to be one foot (EPA 1990). The teenager and others who may have worked in the garden could have been exposed to contaminants through dermal contact, ingestion, and inhalation, depending upon the type and depth of the digging.
The surface impoundment was well vegetated, but relatively free of overgrowth during ATSDR site visits in late 1991. A Georgia Department of Natural Resources' trip report in 1985 described the site as being surrounded by young pines and covered with a thick growth of briars. Before the removal action began, the drum disposal area also was covered with scrub vegetation and briars. That type of ground cover would probably inhibit frequent activity at the sites. Access to the sites was never restricted before removal actions began; if surface soil was contaminated, people may have had dermal contact with and may have incidentally ingested contaminants. The possibility of past exposure and the number of potentially exposed persons cannot be determined. Since removal actions have been completed at both sites, no future exposure to site-related contaminants should occur.
Contaminants may have migrated from the sites and contaminated soil downgradient of either of the sites. Rusting drums, that may have previously contained waste materials, could also contaminate off-site soil. However, only very low concentrations of contaminants were found during subsurface soil sampling that was conducted downgradient of the surface impoundment and beneath rusting drums. The most recent samples of surface water, downslope of the impoundment, did not indicate any apparent site-related contamination. Results from surface water and sediment samples downslope of the drum disposal area also revealed only low levels of contamination, which should further diminish with time, since removal actions have been taken.
Although no surface soil has been sampled downgradient of either site, based upon available environmental data and the fact that removal actions have been conducted, significant contamination of surface soil is not believed to exist. The areas downhill from both sites are wooded, and the ground cover consists of leaves and sparse undergrowth, but show no signs of distressed vegetation. People, who may have dug beneath the leaves or in some other way have used the downgradient areas, may have been exposed to contaminants through dermal contact or incidental ingestion of potentially contaminated soil. The possibility of significant exposure appears unlikely and the number of potentially exposed persons cannot be determined.
The small garden planted in the soil above the surface impoundment could have resulted in exposure for people who ate vegetables from the garden. Uptake of metals from contaminated soil is usually greater in leafy vegetables, such as lettuce, than in tomatoes or peppers (fruit-like vegetables) (EPA 1991b).
Tomato and pepper plants were grown in the garden. According to reports, the produce did not grow well; perhaps only six tomatoes were harvested. A family of three ate the vegetables from the garden and therefore would have also ingested any contaminants in the vegetables (ATSDR 1992l).
Off-site Sediment and Surface Water
People may have been exposed to contaminants in off-site sediment and surface water from the seeps and springs downgradient of the drum disposal and surface impoundment areas. Analysis of samples from the spring downgradient of the drum disposal area showed low levels of site-related contaminants (particularly mercury) in the sediment and low levels of mercury in the surface water. No contamination, above comparison values, was found in the seep downgradient of the surface impoundment. It is possible that either of the springs could have been affected in the past by their respective upgradient sites through groundwater or surface runoff. The surface water and sediment might have been ingested by hunters or passersby who either drank, or took water, from the spring. Although springs are occasionally used as drinking water sources by hunters and hikers, that pathway of exposure is not very likely. The number of such potentially exposed persons cannot be determined.
Ambient air at both sites is a past pathway by which people may have been exposed to site-related contaminants. In March 1985, the drum disposal site caught fire and burned for approximately a week. The wind in the area is typically out of the north/northeast; the nearest homes are scattered from the northwest to east of the drum disposal site (CWMI 1991c). People near the burning site or downwind could have inhaled contaminants during the fire. In addition, wind patterns at the time could have been such that people outside nearby homes could have been exposed.
The surface impoundment also burned (for an unknown length of time) in 1975, and people may have been exposed as a result. Most of the homes close to the surface impoundment were not yet built in 1975. The surface impoundment, as is the drum disposal area, is generally downwind of the nearby homes. People, who were outside near the impoundment or at home within the smoke plume, may have been exposed via inhalation of airborne contaminants.
People may have been exposed by inhalation to contaminants at both sites in the past. The exposure potential would have been greatest to people who were in the area during dumping of waste because, according to reports, odors were detected miles from the site (EPD 1976). The potential for inhalation exposure should have decreased significantly when both sites were covered with soil. When soil was disturbed, such as during removal operations, the release of VOCs and the potential for exposure would have again increased. However, precautions were taken during removal actions at the surface impoundment to prevent the release of VOCs into the community. The residents living in the house closest to the drum disposal area were relocated during removal actions at that site.
VOCs in soil not only escape directly into the air, but also are able to move through the soil; in that form, they are soil gases. As soil gases, contaminants can move through the soil and enter nearby homes through basements, cellars, or even a crawl space. Soil gas also can accumulate in basements.
Although soil gas sampling was conducted at the surface impoundment to determine the extent of contamination, no sampling was conducted to determine whether soil gas was migrating to nearby homes (EPA 1993a). Likewise, no indoor air sampling has been conducted.
Populations, potentially exposed to VOCs at both sites, include nearby residents and people who worked near or visited the sites. The number of such potentially exposed persons cannot be determined. No current or future exposures to airborne contaminants from the sites are expected.
An esitmated 50 on-site workers at the sites could have been exposed to contaminants through inhalation of contaminated air, ingestion of contaminated soil, and skin contact with contaminated soil during past removal actions. It is unlikely that such exposures would occur or be at levels of concern if appropriate work practices, as defined by state or federal regulatory agencies or by permitting authorities, such as the Occupational Safety and Health Administration, have been followed. Such practices include worker education, certification of hazardous waste operations and emergency response training, supervision and training, and use of personal protective equipment.
This section discusses possible health effects in people who may have been exposed to specific contaminants at the two Basket Creek sites, findings from state and local health databases, and specific community health concerns. For residents who live near the Basket Creek Drum Disposal and Surface Impoundment sites, the most likely pathways of exposure to contaminants of concern were: 1) drinking water, 2) the surrounding air, and 3) soil.
The evaluation of health effects involves estimating the amount (or dose) of those contaminants that a person might contact on a daily basis. The estimated exposure dose is then compared to established health-based guidelines developed by ATSDR and other agencies (see Appendix C). People who are exposed for a specified length of time to contaminants of concern, at levels greater than established guidelines, are more likely to have an associated illness or disease. ATSDR discusses many health guidelines in its Toxicological Profiles, which also provide chemical-specific information about health effects, environmental transport, and human exposure.
The main toxicological issue at the Basket Creek sites is whether or not there was access or exposure in the past (before protective remediation measures began) to the contaminants measured in subsurface soil. Because of the presence of relatively high concentrations of certain metals (at the surface impoundment and drum disposal sites) and organic solvents in subsurface soil (at the surface impoundment site), concerns about possible migration to the surface or the air are warranted. Relevant data on surface soil and ambient air (in the past when exposures might have occurred) at the surface impoundment site are not available; therefore, concerns about exposures in the past cannot be evaluated without considerable uncertainty.
Trace Elements and Metals - Private Well Water
Several trace elements and metals (i.e., aluminum, beryllium, iron, lead, molybdenum, and zinc), that are routinely found in raw water supplies and soil in the United States, were found in the Basket Creek private well water samples (Table 5). Note that because those trace elements and metals are commonly found in soil (at background levels), their presence in well water cannot be directly associated with contamination at the drum disposal and surface impoundment sites.
In the past, residents using private well water may have been regularly exposed to those compounds by ingestion of drinking water and by dermal (skin) contact during bathing and washing. Because the skin does not readily absorb trace elements, skin contact with private well water or subsurface soil contaminated with trace elements or metals is not considered a public health threat.
At low levels, iron, molybdenum, and zinc are essential trace elements in the diet and are vital to several enzyme systems in the human body. The maximum levels of iron and zinc found in the private wells were higher than one expects to find in drinking water, but were not greater than levels of public health concern. However, water with excessive levels of iron (greater than 300 µg/L) and zinc (greater than 5,000 µg/L), as were found in several wells, may impart an undesirable taste.
Unlike the essential trace elements discussed previously, aluminum, beryllium, and lead are not known to have any beneficial nutritional effects. Aluminum was found in one well at 17,000 µg/L. If it is assumed that an adult consumes 2 liters of private well water per day, then 34,000 µg of aluminum would be ingested each day. In addition, that amount would be added to the estimated average daily intake of aluminum (from all sources) of 30,000 - 50,000 µg/day (HSDB 1992). Despite the widespread presence of aluminum in foods and drinking water, there is little indication that it is toxic by the oral route. Although it is by no means conclusive evidence, aluminum is one of several factors that has been associated with Alzheimer's disease in drinking water studies (ATSDR 1991c). In addition, skin rashes have been reported in people in England who consumed unknown levels of aluminum sulfate in drinking water, which also contained elevated levels of copper and lead (ATSDR 1991c). It is also important to note that only one private well had very high levels of aluminum (see Table 5).
Beryllium was detected in one of the private wells (at 1.2 µg/L), a level similar to naturally occurring maximum concentrations found in an analysis of 1,577 drinking water samples (ATSDR 1988). Health concerns related to beryllium involve airborne occupational exposure and the possibility of respiratory disease and cancer. There is no evidence that beryllium causes cancer by the ingestion route either in the diet or in drinking water (ATSDR 1988).
The highest level of lead found in private well samples was 66 µg/L. That level is greater than the EPA action level of 15 µg/L for drinking water. Heightened concern about the health effects of lead has resulted in increased public health efforts to minimize environmental exposures. Concerns about lead stem from evidence that children and developing fetuses are especially sensitive to its effects. Excess exposure to lead can induce impaired mental and physical development in infants and children (e.g., learning deficits, impaired hearing, and low birth weight) (ATSDR 1990a). Note that no children were living at the residence with the private well with excess lead levels.
Trace Elements and Metals - Subsurface Soil
Aluminum, arsenic, beryllium, iron, and zinc were found at elevated levels in subsurface soil at the drum disposal site (Table 1). The possibility of exposures to subsurface soil is minimized because of the presence of backfill material (i.e., a clay cover). Additionally, because the skin does not readily absorb trace elements, skin contact with subsurface soil contaminated with trace elements or metals is not considered a public health concern.
The potential for people with access to the site to be exposed (by ingestion or inhalation of dust) to the elevated concentrations found in the subsurface soil is not known with certainty. However, even if it is conservatively assumed that adults ingest 50-100 mg/day of the maximum amount of trace elements or metals found in the drum disposal subsurface soil (Table 1), five days a week for 20 years, there still would be no associated adverse health effects. For children with pica behavior (excessive ingestion of nonfood items), who may inadvertently eat 1,000 times more soil than adults, the likelihood of adverse health effects is very low. It should be emphasized that those risk estimates are conservative because they assume direct access to (subsurface) soil on a regular basis.
Aluminum, beryllium, iron, lead, mercury, selenium, and zinc were detected at elevated levels in subsurface soil at the surface impoundment site (Table 3). Of those compounds, there would be public health concern regarding the possibility of exposure to the amounts of lead (9,400 mg/kg) and mercury (3,553 mg/kg) measured. However, the toxic effects of lead and mercury (e.g., damage to kidneys and neurologic effects) in soil depend upon the amount (dose) received and the duration of exposure, which are not expected to have occurred due to the presence of a clay soil cover.
ATSDR received reports that a garden was briefly maintained near the surface impoundment site, and that tomatoes were harvested. No adverse health effects are expected from the consumption of the garden tomatoes. Studies have shown that some metals (e.g., zinc, cadmium, manganese, selenium) are taken up, to some extent, by plants; other metals (e.g., lead, mercury) may not be taken up because they are typically immobilized or tightly bound in soil, depending on the soil's acidity. Uptake of some metals may be considerable in lettuce, spinach, and other leafy vegetables, but uptake of metals has been reported to be low in tomatoes (EPA 1991b). Furthermore, it is extremely unlikely that plant roots would penetrate several feet to the depth of subsurface soil contamination.
Trace Elements and Metals - Surface (Spring) Water and Sediment
People (and pets) are potentially exposed to contaminants (i.e., aluminum, iron, lead, and mercury) in surface water and sediment downgradient of the drum disposal area (Tables 6 and 7). Aluminum levels in the spring water and sediment were not elevated and are not of public health concern. Iron was detected at very high levels in the surface water. However, humans are not known to suffer harmful effects from drinking water containing iron. Furthermore, iron imparts a strong taste to water at low levels, which very likely makes the spring water unpalatable. Contaminant levels in the spring water and sediment suggest that low levels of mercury may have migrated off site, but not at levels of public health concern. Migration of contaminants off site should diminish in the future because of the remedial efforts that have been undertaken to remove contaminants at the two Basket Creek sites.
Organic Solvents - Surface Water and Private Well Water
Surface water downgradient of the drum disposal area and private well water did not contain elevated levels of organic solvents. Trichloroethene (TCE) was detected at a low level (5 µg/L) in one private well (Table 5) that did not exceed the Maximum Contaminant Level of 5 µg/L, which represents the contaminant concentration that EPA deems protective of public health over a lifetime at an exposure rate of 2 liters of water per day. The level measured slightly exceeded the ATSDR Cancer Risk Evaluation Guide (CREG) value, but the level is not regarded to be of public health concern.
Organic Solvents - Subsurface Soil
Drum disposal subsurface soil did not contain elevated levels of organic solvents. However, organic solvents (i.e., acetone, benzene, methyl ethyl ketone, tetrachloroethene, trichloroethene, and toluene) were found at elevated levels in the surface impoundment subsurface soil samples; those levels significantly exceeded available environmental comparison values (Table 3).
Acetone, methyl ethyl ketone, and toluene are highly volatile, flammable solvents; after prolonged exposures, those substances may depress the central nervous system, irritate mucous membranes, and cause skin dermatitis. The potential toxic effects of those organic solvents depend upon the amount (dose) received and the duration of exposure. The possibility of sustained exposures to subsurface soil was minimized because of the presence of backfill material (i.e., a clay cover).
Benzene, tetrachloroethene, and trichloroethene are other organic solvents that were detected at relatively high levels in the surface impoundment subsurface soil (Table 3). The main public health concern related to exposures to those solvents is the potential for cancer that has been demonstrated in animal studies (and in workers for benzene) (ATSDR 1989c, 1989i, 1990b). Once again, the possibility of sustained exposures to subsurface soil was minimized because of the presence of covering backfill material. Even if it is assumed that adults were able to ingest 50-100 mg/day of the maximum amount of benzene, tetrachloro-ethene, and trichloroethene found in subsurface soil, five days a week for 20 years, there would not be a significant increased risk of cancer. Inhalation exposures to benzene, tetrachloroethene, and trichloroethene cannot be evaluated because the concentrations that volatilized from the soil into the air, from the surface impoundment site, are not known.
Polychlorinated Biphenyls and Di(2-ethylhexyl)phthalate
Polychlorinated biphenyls (PCBs), also known as aroclors, were found at somewhat elevated levels in subsurface soil at the drum disposal site (Table 1) and at the surface impoundment site (Table 3). Di(2-ethyl-hexyl)phthalate (DEHP) was found at somewhat elevated levels at the surface impoundment site (Table 3).
DEHP is a residue of plastics that is widespread in the environment and has low systemic toxicity. DEHP has been shown to cause liver cancer when rats or mice have received sufficiently high doses over their lifetimes (ATSDR 1989d). At the highest concentrations detected in subsurface soil at the Basket Creek sites, DEHP is not of public health concern.
Unlike DEHP, the class of compounds known as PCBs (and aroclors) has considerable toxicity potential. Long-term ingestion of PCB-contaminated soil could have adverse reproductive effects and increase the risk of cancer (ATSDR 1989g). However, PCB exposure would only be of health concern at the two Basket Creek sites, if the contaminated subsurface soil was ingested in unusual amounts, as would be the case in children with pica behavior with access to subsurface soil. In light of remedial activities, those exposures are no longer conceivable.
Medical services were provided to Basket Creek residents by the ATSDR Division of Health Studies, through a contract with Emory University (DHS/EU). Those services included physical examinations and laboratory testing of the blood and urine of 25 current residents and 12 former residents of the Basket Creek community. The blood testing included function tests of the liver, kidney, and hematopoietic and immune systems. The blood of the residents also was tested for VOCs commonly and not commonly found. Residents with any questionable or abnormal test results were counseled or referred to personal physicians for appropriate medical follow-up.
Results of the DHS/EU medical services revealed levels of trichloroethene, trans 1,2-dichloroethene, and chlorobenzene in the blood of a few Basket Creek residents greater than or equal to the 95th percentile of a control group. Those three compounds are relevant because they were contaminants found in on-site subsurface soil (Table 3). The levels of trans 1,2-dichloroethene and chlorobenzene are relatively low compared to trichloroethene (Table 3), but definitive assertions about the possible migration of those contaminants in air cannot be made because of the lack of monitoring data. Besides the potential air pathway, trichloroethene was also found in very low concentrations (5 µg/L) in the groundwater from well number 3. However, ingesting trichloroethene in drinking water at 5 µg/L would not lead to elevated blood TCE levels. Furthermore, the residents using private well number 3 were relocated several months before blood sampling.
In some residents, benzene, ethylbenzene, methylene chloride, and toluene also were detected in blood at levels greater than or equal to the 95th percentile of respective control samples; however, those compounds were found as frequently in residents who had moved away from the Basket Creek sites as in current residents. To delineate whether the presence of those compounds in current and past residents is related to the Basket Creek sites, factors such as the duration of possible exposure (length of residency in the Basket Creek communities), location of residence related to the site, occupational history, and personal activity patterns should be determined. It is important to recognize that nearly everyone, either at work or in the home, is exposed to VOCs (solvents and vapors). Common exposures result from pumping gas, changing oil, shoe repair, furniture manufacture, auto body repair, household cleaners, painting, and gluing. Most VOCs are metabolized and eliminated from the blood within a few days, which suggests that former residents, who had detectable levels of VOCs in their blood, were not exposed to site-related contaminants.
During the investigations by ATSDR health assessors and during the medical examinations by DHS/EU, the community members living near the Basket Creek sites expressed concerns that adverse health effects, such as mouth sores, rashes, and respiratory problems, were related to the Basket Creek sites. As was discussed in the Toxicological Evaluation section, prolonged exposure to high levels of VOCs (that could have been present in the past) has been associated with those types of symptoms. Primarily due to the lack of air monitoring data, ATSDR can not positively determine whether residents were exposed to site-related VOCs in the past. In terms of recent exposures, the evaluation of test results for VOCs in the blood did not indicate that Basket Creek residents were exposed to site-related VOCs.
1. Is the water currently safe to drink?
The Basket Creek residents are now receiving drinking water from the Douglasville-Douglas County Water and Sewer Authority. Samples from two private wells had elevated lead levels and the water from those wells is considered unsafe to drink. Lead could remain a health concern for those households, if their plumbing contains lead piping or solder.
Samples from other private wells had elevated levels of trace elements. Elevated levels of those compounds may impart a bad taste to the water. In addition, aluminum was found at an elevated level in the water of one private well. Some very limited evidence suggests that Alzheimer's disease and rashes are potential health effects of chronic exposure to aluminum in water (at unknown concentrations). In general, it would not be prudent to drink water with excessive amounts of those trace elements for long periods of time.
2. Will the water be safe to drink in the future?
Without proper groundwater characterization, it is not possible to evaluate whether groundwater around the Basket Creek sites will be safe to drink in the future. On-site groundwater sampling has not been conducted. In addition, site-specific geology and groundwater have not been characterized in order to define groundwater flow patterns and the extent of potential contamination.
3. Would the residents' health be affected during cleanup?
From the public health actions taken, it is not likely that any adverse health effects resulted from the removal activities. Specific actions were taken to protect the health of residents near the waste sites during cleanup. During the drum removal, the family living in the house nearest the site was relocated. The family living nearest the surface impoundment was also relocated during removal operations at that site, in addition to the burning of vapors during removal of contaminated soil to prevent their release into the community. Air sampling and monitoring was conducted during remedial activities at both sites.
4. Could mouth sores, rashes, and respiratory problems be related to the site?
The source of aluminum in groundwater is probably naturally occurring, although that has not been documented. Regardless of the source, it is conceivable that rashes could be caused by ingestion of (or skin contact while bathing with) elevated levels of aluminum (i.e., 17,000 µg/L) from drinking water detected in one well. Mouth sores are probably not related to the site. Prolonged exposure to high levels of volatile organic solvents (found in subsurface soil) could be associated with respiratory problems. However, no data on ambient air exist to assess past exposures.
5. Do children in the neighborhood have high blood lead levels resulting from the sites?
Based on results of the personal medical exams conducted through the ATSDR Division of Health Studies' case series, no children in the neighborhood revealed high blood lead levels.
6. Could the residents' health problems over the years be a result of the two sites?
If residents have been exposed for some critical length of time to underlying subsurface soil, or to volatile organic emissions from soil, some health problems could be a result of exposure to the sites. However, this is considered to be unlikely.
7. Did the previous fires adversely affect the residents health?
There are no air data available indicating the concentrations of contaminants present in the air, particularly near the homes and residents that were living in the Basket Creek area at the time that the fires took place. Such information would be needed to accurately evaluate what adverse health effects might have resulted.
8. Will children, pets, or hunters be affected by potential future spring water contamination?
People (and pets) are potentially exposed to contaminants (i.e., aluminum, iron, and mercury) in surface water downgradient of the drum disposal area. Aluminum levels in the spring water were not elevated and are not of public health concern. Iron was detected at very high levels in the surface water. However, humans are not known to suffer harmful effects from drinking water containing iron. Furthermore, iron imparts a strong taste to water at low levels, which very likely makes the spring water unpalatable. Contaminant levels in the spring water suggests that low levels of mercury may have migrated off site, but not at levels of public health concern. Migration of contaminants off site should diminish in the future because of the remedial efforts that have been conducted to remove contaminants at the two Basket Creek sites.
9. Has waste been buried in the Basket Creek area, other than that being removed from the surface impoundment and drum disposal area?
There is no evidence of any additional hazardous waste sites in the Basket Creek area. In an effort to address concerns regarding the presence of additional hazardous waste sites, EPA conducted further investigations. However, no additional hazardous waste sites were found in the Basket Creek area.